\documentclass{book}%
% header.tex
% useful tricks:
% grep "\.eps>" cft.log > tmp
% ls -sa | sort -n
%
% better:
% showIncludes.p cft.log > tm
% source tm
% don't like [osf] - I got mixed numbers
%\usepackage[osf]{mathpazo}% GLOBAL FONT CHOICE -- see fonts and test.tex also ~/tex/fonts*pdf
%\usepackage{mathpazo}% GLOBAL FONT CHOICE -- see fonts and test.tex also ~/tex/fonts*pdf
\usepackage[sc]{mathpazo}% GLOBAL FONT CHOICE -- see fonts and test.tex also ~/tex/fonts*pdf
%\usepackage[sc]{mymathpazo}% GLOBAL FONT CHOICE -- see fonts and test.tex also ~/tex/fonts*pdf
% note the font has been modified as described in tex/inputs
% using the ``sc'' option increases the lead between lines and the spacing between words.
% it also loses the difference between {\sl} and {\em.}
\usepackage{refcount}% required in order to be able to use \pageref{} as a number (mynotes.sty)
%% ftp://ctan.tug.org/tex-archive/macros/latex/contrib/oberdiek/refcount.pdf
\usepackage{mynotes}% used to automate smart numbering of page references
\usepackage{myqa}% used in myths.tex
\usepackage{natbib}% citation style
\usepackage{colordvi}
%% see crop.tex
\usepackage{epsf}
\usepackage{epsfig}
\usepackage{paralist}% allows running lists
%% eg \begin{inparaenum}[\itshape a\upshape)]
\usepackage{wasysym}% provides dingbats (used for fullmoon symbol etc)
%\usepackage[greek]{babel}% to get {euro}
%\usepackage{textcomp}% provides euro
%\usepackage[T1]{fontenc} recommended to get other extended fonts
\usepackage[official,right]{eurosym}
% \usepackage{europs}% provides a symbol called \EURtm or \ppleuro (not installed)
\usepackage{graphicx}% provides ability to crop margins!
%\usepackage{hyperref} Seems to interfere with other packages
\usepackage{notes}% provides endnotes for chapters
\usepackage{cft10} % provides header and footer defns and page sizes
\usepackage{cents} % provides \cents
%\usepackage{chapternotes}% lots of assorted stuff
% \usepackage{ourbox2} %
\usepackage{mparhackright-209} % forces all marginpars onto the right column.
\usepackage{textcomp} % provides textdegree
\usepackage{fancybox}% Provides ability to put verbatim text inside boxes
\usepackage{boxedminipage}
\usepackage{myalgorith}% provides ``floatseq'' for labelling figs and tables
\usepackage{mycaption10}% defines ``\indented''and \@makecaption; and the notindented style used in figure captions
\usepackage{marginfig}% Defines many macros for making various styles of figure with captions, and framedalgorithms
%\usepackage{lsalike}% defines citation commands
\usepackage{booktabs}% makes nice quality tables
\usepackage{ragged2e}% provides \justifying
\usepackage{mycenter}% modifies center to reduce vertical space waste - useful for figures, etc.
\usepackage{mypartCFT}% modifies part to not cleardoublepage
\usepackage{prechapter10}% defines a chapter-like object Used for ``Preface'' and List Of Web Links
\usepackage{mychapter10}% defines chapter, including look of new chapter page See also mytoc
% also the look of the section and subsection commands
\usepackage{myheadingsCFT}% redefines the pagestyle `headings'
\usepackage{myindex}% overrides book definition of index was myindex4
\usepackage{makeidx}
%% from crckapb.sty
\usepackage[allowmove]{url}% see also texdefns which modifies the way url rendered
\usepackage{djcmurls}
\usepackage{whingelist}
\usepackage{multicol}% used in the bibliography
\usepackage{mybibliog}
\usepackage{myerrata}%% added for Errata.tex only
\usepackage{tocloft}% implements my look of table of contents
\usepackage{tocloftcomp2}% implements my look of table of contents (was toclo
\usepackage{mytoc}% suppresses the CONTENTS headings
\usepackage{layout}% requested by NMM
\usepackage{myfloat}% allows floating object like figure
% but with no number interference
%% tocloft has clash with hyperref. See page 2 of tocloft documentation
\makeindex
\renewcommand{\textfraction}{0.10}
\usepackage{seealso}
\usepackage{prelims}% dedication
% suggestions from NMM:
%\setcounter{topnumber}{5}
%\renewcommand\topfraction{1}%% was 0.7; changed as otherwise large screenshots go walkies
%\setcounter{bottomnumber}{5}
%\renewcommand\bottomfraction{1}%% was 0.5
%\setcounter{totalnumber}{10}
%\renewcommand\textfraction{0}
%\renewcommand\floatpagefraction{.5}
\setcounter{tocdepth}{0}
\pagestyle{headings}
% end of header10.tex
%\documentclass[11pt]{book}% see also mgp -O -U youfigure.mgp ... source DOY
%%% make cft.pdf
%%% make sewthamono.pdf
% \input{header.tex}
\begin{document}
\newcommand{\thedraft}{3.6.0}% 3.5.2 final version Dec 1 2009
% header2.tex
% .bst
\bibliographystyle{abbrvnatdjcm}% see mybibliog.sty CHANGE THIS ***
%\bibliographystyle{abbrvnat}% see mybibliog.sty CHANGE THIS ***
%\bibliographystyle{lsalikedjcmsc}%.bst
% To include this file use
% \include{/home/mackay/tex/newcommands1}
%\newcommand{\eR}{{^{\rm R}}{\bf e}}
%\newcommand{\eL}{{^{\rm L}}{\bf e}}
%
\newcommand{\onedelta}{{1}}
\newcommand{\kilobyte}{kilobyte}
\newcommand{\kilobytes}{{\kilobyte}s}
\newcommand{\bomegab}{{\bf \omega}}
\newcommand{\bomega}{\underline{\omega}}
%\newcommand{\curl}{\mbox{curl}\,}
\newcommand{\Div}{\mbox{div}\,}
\newcommand{\Grad}{\mbox{grad}\,}
\newsavebox{\leftDbox}
\savebox{\leftDbox}{%
\setlength{\unitlength}{0.01cm}
\begin{picture}(36,36)(14,-18)
\put(50,0){\makebox(0,0){\makebox[0in][r]{$\langle$}{\sc{d}}}}
\put(65,18){\line(-1,0){27}}
\put(65,-18){\line(-1,0){27}}
\put(65,18){\line(0,-1){36}}
\end{picture}
}
\newcommand{\leftD}{\usebox{\leftDbox}}
% was \cup, \cap
\newcommand{\convexsmile}{convex$\,\smile$}
\newcommand{\concavefrown}{concave$\,\frown$}
\newcommand{\Convexsmile}{Convex$\,\smile$}
\newcommand{\Concavefrown}{Concave$\,\frown$}
%%%%%%%%% the following are provided for error-correction
\newcommand{\convexfrown}{\concavefrown}
\newcommand{\concavesmile}{\convexsmile}
\newcommand{\perfectic}{raw bit content}
\newcommand{\Perfectic}{Raw bit content}
\newcommand{\essentialic}{essential bit content}
\newcommand{\Essentialic}{Essential bit content}
\newcommand{\eR}{{\bf e}_{\small{\sf R}}}
\newcommand{\eL}{{\bf e}_{\small{\sf L}}}
\newcommand{\eRa}{{\bf e}_{\small{\sf R}}^{(a)}}
\newcommand{\eLa}{{\bf e}_{\small{\sf L}}^{(a)}}
\newcommand{\eRb}{{\bf e}_{\small{\sf R}}^{(b)}}
\newcommand{\eLb}{{\bf e}_{\small{\sf L}}^{(b)}}
\newcommand{\fRa}{{\bf f}_{\small{\sf R}}^{(a)}}
\newcommand{\fLa}{{\bf f}_{\small{\sf L}}^{(a)}}
\newcommand{\fRb}{{\bf f}_{\small{\sf R}}^{(b)}}
\newcommand{\fLb}{{\bf f}_{\small{\sf L}}^{(b)}}
\newcommand{\gRa}{{\bf g}_{\small{\sf R}}^{(a)}}
\newcommand{\gLa}{{\bf g}_{\small{\sf L}}^{(a)}}
\newcommand{\gRb}{{\bf g}_{\small{\sf R}}^{(b)}}
\newcommand{\gLb}{{\bf g}_{\small{\sf L}}^{(b)}}
\newcommand{\bref}[1]{(\ref{#1})}
\newcommand{\eqref}[1]{equation~(\ref{#1})}
\newcommand{\eqsref}[2]{equations~(\ref{#1}--\ref{#2})}
\newcommand{\eqbref}[1]{(equation~\ref{#1})}
\newcommand{\Eqref}[1]{Equation~(\ref{#1})}
\newcommand{\algref}{algorithm~\ref}
\newcommand{\Algref}{Algorithm~\ref}
\newcommand{\boxref}{box~\ref}
\newcommand{\Boxref}{Box~\ref}
\newcommand{\figref}{figure~\ref}
\newcommand{\Figref}{Figure~\ref}
\newcommand{\figsref}{figures~\ref}
\newcommand{\Figsref}{Figures~\ref}
\newcommand{\tabref}{table~\ref}
\newcommand{\tablenoun}{table}
\newcommand{\Tabref}{Table~\ref}
\newcommand{\ind}[1]{#1\index{#1}}
\newcommand{\indexs}[1]{\index{#1|bold}}
\newcommand{\inds}[1]{#1\indexs{#1}}% special index entry
\newcommand{\indit}[1]{#1\index{#1|it}}% special index entry
%
% see also newcommands2.tex
% index entries: if I use \inds{blob}
% it is a special index entry that comes out
% \indexentry{alpha|bold}{1}
% which is then converted by makeindex into a bold page number
\newcounter{frompage}
\setcounter{frompage}{0}
%
% see itp/dvips_maker.p for ideas on this stuff:
%
% original idea: make dvips commands for making separate ps docs
% idea 2: use pstops to select pages from the mega document.
%
% current method: terminate chapters or spit out generic stuff using \dvips
% On special occasions add own label using \dvipsb
%
\newcommand{\dvipsspecial}[1]{\setcounter{frompage}{#1}}
\newcommand{\dvips}{\ifnum \arabic{frompage} < \arabic{page}
\typeout{\# dvips Chapter \arabic{chapter} }
\typeout{ dvips -p \arabic{frompage} -l \arabic{page} -o ps/\arabic{frompage}.\arabic{page}.ps }
\setcounter{frompage}{\arabic{page}}
\addtocounter{frompage}{1}
\else
\typeout{ Already printed to here}
\fi
}
\newcommand{\dvipsb}[1]{\ifnum \arabic{frompage} < \arabic{page}
\typeout{\# dvips #1}
% \typeout{#1}
\typeout{ dvips -p \arabic{frompage} -l \arabic{page} -o ps/\arabic{frompage}.\arabic{page}.ps }
\setcounter{frompage}{\arabic{page}}
\addtocounter{frompage}{1}
\else
\typeout{ Already printed to here}
\fi
}
\newcommand{\sfhead}[1]{\medskip
{\sf #1 }\\
}
\newcommand{\schead}[1]{\medskip
{\sc #1 }\\
}
\newcommand{\argmin}{{\mbox{argmin}}}
\newcommand{\linefrac}[2]{{#1}/{#2}}
\newcommand{\partl}[1]{ \frac{\partial}{\partial #1 } }
\newcommand{\ppartl}[2]{ \frac{\partial^2}{\partial #1 \partial #2 } }
\newcommand{\putoval}[3]{\put(#1){\oval(#2)}
\put(#1){\makebox(0,0){#3}}}
\newtheorem{pseudo}{Pseudo-theorem}
\newcommand{\PC}{{\bf PC}}
\newcommand{\trans}{{\rm\scriptscriptstyle T}}
\newcommand{\Psc}{\bf P_{\bf s \bf c}}
\newcommand{\PscC}{\bf P_{\bf s \bf c} \bf C}
\newcommand{\Pn}{\bf P_{\bf n}}
%\newcommand{\fN}{\frac{1}{N}}% replaced by fN in itprnnchapter.tex
\newcommand{\wrt}{with respect to}
\newcommand{\Xl}{\makebox{$X$}}
\newcommand{\mod}{\,\mbox{mod}\,}
\newcommand{\MCMC}{Markov chain Monte Carlo}
%\newcommand{\argmax}{\,\mbox{argmax}\,}
% http://www.theochem.kun.nl/tex/FAQ/english/texfaq_89.html
\newcommand{\argmax}{\mathop{\rm argmax}}
% If you want your subscripts and superscripts
% always placed to the right, do:
% \newcommand{\diag}{\mathop{\rm diag}\nolimits}
\newcommand{\diag}{\mathop{\rm diag}}
\newcommand{\Yl}{\makebox{$Y$}}
\newcommand{\Xo}{\makebox{$\bar{X}$}}
\newcommand{\Yo}{\makebox{$\bar{Y}$}}
%\newcommand{\Xl}{\makebox{$X\!=\!1$}}
%\newcommand{\Yl}{\makebox{$Y\!=\!1$}}
%\newcommand{\Xo}{\makebox{$X\!=\!0$}}
%\newcommand{\Yo}{\makebox{$Y\!=\!0$}}
\newcommand{\noprint}[1]{}
\newcommand{\struta}{\rule{0cm}{14pt}}
\newcommand{\strutb}{\rule{0cm}{12pt}}
\newcommand{\strutc}{\rule{0cm}{19pt}}
\newcommand{\strutd}{\rule[-9pt]{0pt}{29pt}}
\newcommand{\strutf}{\rule{0cm}{12pt}}% for supporting lines above fractions in tables (eg chap 5 of book)
\newlength{\xx}
\newlength{\xxx}
\newlength{\yy}
\setlength{\xx}{1.4in}%
\setlength{\xxx}{2.8in}%
\setlength{\yy}{4in}%
%\newcommand{\struta}{\rule{0cm}{2\baselineskip}}
%\newcommand{\strutb}{\rule{0cm}{3\baselineskip}}
\newcommand{\Trace}{\mbox{Trace}\,}
\newcommand{\ssN}{\scriptscriptstyle N}
\newcommand{\ssNN}{{\scriptscriptstyle N\!+\!1}}
\newcommand{\bssNN}{{\scriptscriptstyle (N\!+\!1)}}
\newcommand{\ssNM}{\scriptscriptstyle N\!-\!1}
\newcommand{\etal}{{\em et~al.}}
\newcommand{\chiD}{\chi^2_{\scriptscriptstyle D}}
\newcommand{\chiW}{\chi^2_{\scriptscriptstyle W}}
\newcommand{\bg}{{\bf g}}
\newcommand{\g}{{\bf g}}
\newcommand{\bu}{{\bf u}}
\newcommand{\bd}{{\bf d}}
\newcommand{\bD}{{\bf D}}
\newcommand{\bL}{{\bf L}}
\newcommand{\bl}{{\bf l}}
\newcommand{\Do}{ \Delta^{\! 0}}
\newcommand{\wo}{{\setminus}}
\newcommand{\FE}{\rm \scriptscriptstyle FE}
\newcommand{\MP}{\rm \scriptscriptstyle MP}
\newcommand{\ML}{\rm \scriptscriptstyle ML}
%\newcommand{\amp}{a^{\rm \scriptscriptstyle MP}}
\newcommand{\amp}{\alpha_{\rm \scriptscriptstyle MP}}
\newcommand{\aamp}{a_{\rm \scriptscriptstyle MP}}
\renewcommand{\d}{{\rm{d}}}% was \mbox{d}
\newcommand{\D}{{\cal D}}
\newcommand{\B}{{\cal B}}
\newcommand{\V}{{\cal V}}
\newcommand{\BC}{${\cal B \rightarrow C}$}
\newcommand{\C}{\cal C}
\newcommand{\G}{\cal G}
%%%%%%%
\font\blah=cmss8 at 7pt
\def\myT{{\blah T}}
%%%%%%%
\font\tinytt=cmtt8 at 6pt
\font\tinysf=cmss8 at 6pt
\def\T{\hspace*{-0.2mm}\mbox{\tinysf T}\hspace*{-0.2mm}}
%\def\T{\hspace*{-0.2mm}{\tinysf T}}
% \newcommand{\T}{\!\mbox{\tiny\sf T}}
% \newcommand{\T}{{\top}}
% \newcommand{\T}{\makebox[0in][r]{$\top$}}
% \newcommand{\T}{{\sf \scriptscriptstyle T}}
\newcommand{\N}{{\cal N}}
\newcommand{\Normal}{\mbox{Normal}}
\newcommand{\A}{{\cal A}}
\newcommand{\R}{{\cal R}}
\renewcommand{\S}{{\cal S}}
\newcommand{\Sa}{{{\cal S}_1}}
\newcommand{\Sb}{{{\cal S}_2}}
\newcommand{\F}{$\cal F$}
\newcommand{\FG}{$\cal F \rightarrow G$}
%\newcommand{\btheta}{{\bf \theta}}
% moved to 2e.tex
\newcommand{\bp}{{\bf p}}
\newcommand{\bw}{{\bf w}}
\newcommand{\bW}{{\bf W}}
\newcommand{\w}{{\bf w}}
\newcommand{\bm}{{\bf m}}
\newcommand{\sigW}{\sigma_{\scriptscriptstyle W}}
\newcommand{\wml}{{{\bf w}_{\rm \scriptscriptstyle ML}}}
\newcommand{\wmp}{{\bf w}_{\rm \scriptscriptstyle MP}}
\newcommand{\wmpa}{{\bf w}_{{\rm \scriptscriptstyle MP}|\alpha}}
\newcommand{\wmpam}{{\bf w}_{{\rm \scriptscriptstyle MP}|\alpha_{\MP}}}
\newcommand{\wmpabar}{{\bf w}_{{\rm \scriptscriptstyle MP}|\bar{\alpha}}}
\newcommand{\aeff}{\alpha_{\rm eff}}
\newcommand{\MAP}{MAP}
\newcommand{\snu}{\sigma_{\nu}}
\newcommand{\hb}{\hat{\beta}}
\newcommand{\ha}{\hat{\alpha}}
\newcommand{\p}{{\bf p}}
\renewcommand{\P}{{\cal P}}
\newcommand{\m}{{\bf m}}
\newcommand{\br}{{\bf r}}
\newcommand{\f}{{\bf f}}
\newcommand{\bff}{{\bf f}}
\newcommand{\fmp}{{\bf f}_{\MP}}
\newcommand{\bth}{\underline{\theta}}
%\newcommand{\bth}{{\bf \theta}}
\newcommand{\bQ}{{\bf Q}}
\newcommand{\bq}{{\bf q}}
\newcommand{\bB}{{\bf B}}
\newcommand{\ba}{{\bf a}}
\newcommand{\bbb}{{\bf b}}
\newcommand{\NB}{{\it N.B.}}
\newcommand{\eg}{{\it e.g.}}
\newcommand{\ie}{{\it i.e.}}
\newcommand{\cf}{{\it cf.}}% fixed Wed 31/12/03
\newcommand{\qb}{\bar{q}}
\newcommand{\barx}{\bar{x}}
\newcommand{\bP}{{\bf P}}
%\newcommand{\r}{\rho}% moved to 2.tex
\newcommand{\bJ}{{\bf J}}
\newcommand{\bk}{{\bf k}}
\newcommand{\bK}{{\bf K}}
\newcommand{\bC}{{\bf C}}
\newcommand{\bG}{{\bf G}}
\newcommand{\bH}{{\bf H}}
\newcommand{\bY}{{\bf Y}}
\newcommand{\bA}{{\bf A}}
\newcommand{\bF}{{\bf F}}
\newcommand{\bE}{{\bf E}}
\newcommand{\bT}{{\bf T}}
\newcommand{\bR}{{\bf R}}
\newcommand{\tR}{\tilde{R}}
\newcommand{\tF}{\tilde{F}}
\newcommand{\tW}{\tilde{W}}
\newcommand{\tD}{\tilde{D}}
\newcommand{\bSig}{{\bf \Sigma}}
\newcommand{\bAI}{{\bf A}^{\!\! -1}}
\newcommand{\bM}{{\bf M}}
\newcommand{\bN}{{\bf N}}
\newcommand{\bh}{{\bf h}}
\newcommand{\bX}{{\bf X}}
\newcommand{\sN}{\sqrt{N}}
\newcommand{\st}{\sqrt{3}}
\newcommand{\sm}{\sqrt{m}}
\newcommand{\bz}{{\bf z}}
\newcommand{\bn}{{\bf n}}
\newcommand{\bI}{{\bf I}}
\newcommand{\hn}{{\bf \hat{n}}}
\newcommand{\he}{{\bf \hat{e}}}
\newcommand{\var}{\mbox{var}}
\newcommand{\be}{{\bf e}}
\newcommand{\bc}{{\bf c}}
\newcommand{\xmx}{x_{\max}}
\newcommand{\xmn}{x_{\min}}
\newcommand{\bx}{{\bf x}}
\newcommand{\by}{{\bf y}}
\newcommand{\bv}{{\bf v}}
%\newcommand{\defeq}{\stackrel{\tiny \triangle}{=}}
\newcommand{\smalldfrac}[2]{\mbox{{\raisebox{1.7pt}{\tiny{#1}}}%
\hspace{-0.375mm}{\raisebox{0pt}{\footnotesize{/}}}\hspace{-0.3mm}%
{{\tiny{#2}}}}}
\newcommand{\dfrac}[2]{\mbox{{\raisebox{3pt}{\footnotesize{#1}}}%
\hspace{-0.4mm}{\raisebox{2pt}{\small{/}}}\hspace{-0.4mm}%
{{\footnotesize{#2}}}}}
\newcommand{\mdfrac}[2]{\mbox{{\raisebox{3pt}{\footnotesize{$#1$}}}%
\hspace{-0.4mm}{\raisebox{2pt}{\small{/}}}\hspace{-0.4mm}%
{{\footnotesize{$#2$}}}}}
\newcommand{\dfifth}{\dfrac{1}{5}}
\newcommand{\dtwofifth}{\dfrac{2}{5}}
\newcommand{\iid}{i.i.d.}
\newcommand{\dthird}{\dfrac{1}{3}}
\newcommand{\dsixth}{\dfrac{1}{6}}
\newcommand{\deighth}{\dfrac{1}{8}}
\newcommand{\dsixteenth}{\dfrac{1}{16}}
\newcommand{\dthirtytwoth}{\dfrac{1}{32}}
\newcommand{\dquarter}{\dfrac{1}{4}}
\newcommand{\dhalf}{\dfrac{1}{2}}
\newcommand{\half}{\frac{1}{2}}
\newcommand{\hf}{{1/2}}
\newcommand{\grad}{\nabla}
\newcommand{\lfrac}[2]{\left.{#1}\right/{#2}}
\newcommand{\ben}{\begin{enumerate}}
\newcommand{\een}{\end{enumerate}}
\newcommand{\beq}{\begin{equation}}
\newcommand{\eeq}{\end{equation}}
\newcommand{\beqa}{\begin{eqnarray*}}
\newcommand{\eeqa}{\end{eqnarray*}}
\newcommand{\beqan}{\begin{eqnarray}}
\newcommand{\eeqan}{\end{eqnarray}}
%\newcommand{\bt}{\begin{tabular}{c}}
\newcommand{\bt}{{\bf t}}
\newcommand{\btt}{\begin{tabular}}
\newcommand{\et}{\end{tabular}}
\renewcommand{\l}{\lambda}
% \newcommand{\dw}{{\w-\wml}}
\newcommand{\siguW}{\sigma^{\scriptscriptstyle w}}
\newcommand{\Q}{Q}
\newcommand{\q}{q}
\newcommand{\hw}{\hat{\bf w}}
\renewcommand{\b}{\beta}
\newcommand{\bo}{\beta_{\omega}}
\newcommand{\EDo}{E_{D(\omega)}}
\newcommand{\Bo}{{\bf B}_{\omega}}
\newcommand{\No}{N_{\omega}}
\newcommand{\go}{\gamma_{\omega}}
\newcommand{\gc}{\gamma_c}
\renewcommand{\a}{\alpha}
\newcommand{\Hs}{{\cal H}_{\bar{s}}}
\newcommand{\ws}{{\bf w}^{\MP}_{\bar{s}}}
% \newcommand{\bs}{{\bf e}_{s}}
\newcommand{\bs}{{\bf s}}
\newcommand{\bS}{{\bf S}}
\newcommand{\dw}{\Delta {\bf w}}
\newcommand{\bAs}{{\bf A}_{\bar{s}}}
\newcommand{\ns}{\bar{s}}
\newcommand{\wns}{{\bf w}_{\bar{s}}}
\newcommand{\bU}{{\bf U}}
\newcommand{\bV}{{\bf V}}
\newcommand{\kB}{{k_{\rm B}}}
\newcommand{\kb}{{k_{\rm B}}}
%
\newtheorem{thm}{Theorem}
%\newtheorem{ctheorem}{Theorem}[chapter]
% the above commented out because 2e doesn't like chapter
\newtheorem{prop}{Property}
\newtheorem{conj}{Conjecture}
\newcommand{\pf}{{\noindent\em Proof. }}
\newcommand{\epfsymbol}{\Box}%{\bullet}%% requries \usepackage{latexsym}
\newcommand{\eepf}{\eqno\epfsymbol }
\newcommand{\epf}{\hfill$\epfsymbol$ \\[0.15in]}
\renewcommand{\a}{\alpha}
\renewcommand{\b}{\beta}
\renewcommand{\R}{{\cal R}}
\renewcommand{\H}{{\cal H}}
\newcommand{\I}{{I}}%%%%%%%%%%%%%%%%% mutual information
\newcommand{\M}{{\cal M}}
\renewcommand{\C}{{\cal C}}
\newcommand{\pdxy}[2]{{{\partial #1}\over{\partial #2}}}
\newcommand{\Exp}{{\cal E}}% expectation
% \newcommand{\emph}[1]{{\em #1\/}}
% not needed in 2e ^^^^^
%
% sanjoy units method:
\def\unit#1{\,{\rm #1}}
\def\cm{\unit{cm}}
\def\kg{\unit{kg}}
\def\cm{\rm{cm}}
\def\kg{\rm{kg}}
%
% Page
\newcommand{\pref}[1]{\mbox{\pdot\pageref{#1}}}% produces page reference
\newcommand{\Pref}[1]{\mbox{\Pdot\pageref{#1}}}% produces page reference
\newcommand{\Pageref}[1]{\mbox{\Pdot\pageref{#1}}}% produces page reference
\newcommand{\pdotsmall}{p.\hspace{0.17mm}}
\newcommand{\pdot}{p.\hspace{0.25mm}}
\newcommand{\Pdot}{P.\hspace{0.25mm}}
%
\newcounter{mycounter}
\newcommand\leftmarginpar[1]{%
\stepcounter{mycounter}%
\label{leftmargin:\arabic{mycounter}}
\ifodd\mp@pageref{leftmargin:\arabic{mycounter}}
\begingroup
\reversemarginpar\marginpar{#1}%
\endgroup
\else
\marginpar{#1}%
\fi
}
%
% ensemblePaper.tex:
%
\newcommand{\Hfill}{\hfill\hfill\hfill\hfill\hfill\hfill}%% \stretch{100}}%%
\newcommand{\Dir}[3]{\mbox{$\mbox{Dirichlet}^{(#3)}(#1\,|\,#2)$}}
\newcommand{\Dirichlet}[2]{\mbox{$\mbox{Dirichlet}\left({#1};{#2}\right)$}}
\newcommand{\durlc}[1]{\begin{center}\url{#1}\end{center}}
\newcommand{\durl}[1]{\Hfill\linebreak[3]\hfill\url{#1}\par}
\newcommand{\durlp}[1]{\Hfill\linebreak[4]\hfill\url{#1}\par}
\newcommand{\svec}[1]{\underline{#1}}
\newcommand{\dvec}[1]{\underline{\underline{#1}}}
%
\newcommand{\dvA}{{\bf A}}
\newcommand{\dvB}{{\bf B}}
\newcommand{\svpi}{{\pi}}
\newcommand{\svp}{{\bf p}}
\newcommand{\svq}{{\bf q}}
\newcommand{\svU}{{\bf U}}
\newcommand{\svw}{{\bf w}}
\newcommand{\svm}{{\bf m}}
\newcommand{\sva}{{\bf a}}
%
\newcommand{\dvUA}{{\bf u}^{(A)}}
\newcommand{\dvUB}{{\bf u}^{(B)}}
\newcommand{\svUpi}{{\bf u}^{(\pi)}}
%
% jordan.tex:
%
\newcommand{\state}{\{i_l,j_l\}_1^L}
%
% sparsecodes.tex
\newcommand{\ldpc}{{low--density parity--check}}
\newcommand{\Ldpc}{{Low--density parity--check}}
\newcommand{\erf}{\Phi}
%
% for itp/book
\newcommand{\sixtoone}[2]{%
\begin{tabular}{c}
#1\\
\mbox{\psfig{figure=figs/sixtoone/#2.ps,width=1.1in,angle=-90}\hspace*{0.21in}}\\
\end{tabular}
}
%
% from gp.tex
\newcommand{\dCda}{{\frac{\partial \bC_{N}}{\partial \theta}}}
\newcommand{\cO}{{\cal O}}
\newcommand{\cR}{{\cal R}}
\newcommand{\cN}{{\cal N}}
\newcommand{\cG}{{\cal G}}
\newcommand{\bkNN}{{\bf k}}% \bk_{N+1}
\newcommand{\bxt}{{\tilde{\bf x}}}
\newcommand{\tNN}{t_{N+1}}
\newcommand{\tN}{t_{N}}
\newcommand{\bCN}{{\bf C}_{N}}
\newcommand{\bCNN}{{\bf C}_{N+1}}
\newcommand{\btN}{{\bf t}_{N}}
\newcommand{\btNN}{{\bf t}_{N+1}}
\newcommand{\byN}{{\bf y}_{N}}
\newcommand{\byNN}{{\bf y}_{N+1}}
\newcommand{\bXN}{{\bf X}_{N}}
\newcommand{\bXNN}{{\bf X}_{N+1}}
\newcommand{\tn}{t_{n}}
\newcommand{\bCinv}{{\bf C}^{-1}}
\newcommand{\bGinv}{{\bf \Gamma}^{-1}}
\newcommand{\bHinv}{{\bf H}^{-1}}
\newcommand{\Zinv}{Z^{-1}}
\newcommand{\cC}{{\cal C}}
\newcommand{\cD}{{\cal D}}
\newcommand{\cL}{{\cal L}}
%
% from GM
\newcommand{\ket}[1]{\ensuremath{\left | #1 \right \rangle}}
\newcommand{\bra}[1]{\ensuremath{\left \langle #1 \right |}}
\newcommand{\dd}[2]{\frac{\partial #1}{\partial #2}}
%\newcommand{\ij}{_{ij}}
%\renewcommand{\ij}{_{ij}}
\def\argmin{\mathop{\rm argmin}}
\def\argmax{\mathop{\rm argmax}}
\def\breakhere{\hskip 1sp}
% To include this file use
% \include{/home/mackay/tex/newcommands2}
%
% This file contains commands that are only acceptable in some
% documentstyles.
%
\newcommand{\bit}{\begin{itemize}}
\newcommand{\eit}{\end{itemize}}
%
\newtheorem{theorem}{Theorem}
\newtheorem{lemma}{Lemma}
% replaced in chapternotes.sty::::
%\newenvironment{example}[1]{\begin{quotation} \noindent
% {\sf Example: #1}\\[0.1in]
% }{\end{quotation}}
\newenvironment{keywords}{\begin{quotation}{\bf Keywords:} \noindent}{\end{quotation}}
% \newtheorem{example}{Example}
\newtheorem{corollary}{Corollary}
\newtheorem{ass}{Assumption}
\newtheorem{lem}{Lemma}
\newtheorem{res}{Result}
\newtheorem{cond}{Condition}
\newtheorem{defin}{Definition}
% \newtheorem{definc}{Definition}[chapter]
% used in pascal and nn2
% the above commented out of newcommands1.tex because of the llncs style
% complaining.
%
% useful for makeindex stuff
\newcommand{\bold}[1]{{\bf{#1}}}
% removed this Tue 7/1/03 because it conflicts with \usepackage{makeidx}
% \newcommand{\see}[2]{{{\it{see\/}} #1}}% note this ignores the second arg, which is a page number.
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% see also djcmurls.sty
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\@ifundefined{selectfont}{\def\UrlFont{\sf}}{\def\UrlFont{\small\ttfamily}}}
\def\url@leotinystyle{%
\@ifundefined{selectfont}{\def\UrlFont{\sf}}{\def\UrlFont{\tiny\ttfamily}}}
\def\url@leoscriptstyle{%
\@ifundefined{selectfont}{\def\UrlFont{\sf}}{\def\UrlFont{\scriptsize\ttfamily}}}
\def\url@leofootnstyle{%
\@ifundefined{selectfont}{\def\UrlFont{\sf}}{\def\UrlFont{\footnotesize\ttfamily}}}
\makeatother
%% Now actually use the newly defined style.
\urlstyle{leo}
% to make things even smaller,
% \urlstyle{leotiny}
% \urlstyle{leofootn}
%% from http://www.kronto.org/thesis/tips/url-formatting.html
% Black and White BW -> mono monochrome (not colour) bwed is mono{}{}
\newcounter{layouts}\setcounter{layouts}{0}%
\newcounter{monoed}\setcounter{monoed}{0}%
\newcounter{uked}\setcounter{uked}{1}%
\newcounter{lowresed}\setcounter{lowresed}{1}%
\newcounter{leveltwo}\setcounter{leveltwo}{0}% controls type of postscript
\newcommand{\mono}[2]{\ifnum \themonoed=1{#1}\else{#2}\fi}
\newcommand{\uk}[2]{\ifnum \theuked=1{#1}\else{#2}\fi}
%% example \uk{motorway}{freeway}
\newcommand{\lowres}[2]{\ifnum\thelowresed=1{#1}\else{#2}\fi}
\newcommand{\leveltwo}[2]{\ifnum\theleveltwo=1{#1}\else{#2}\fi}
\newcommand{\pkm}{p-km}
\newcommand{\ml}{ml}% cm$^3$
\newcommand{\tkm}{t-km}
\newcommand{\lesslead}{\baselineskip 10.65pt plus 1pt minus 0.5pt}
\newcommand{\frcol}[1]{{\DarkOrchid{#1}}} % freight intensity
\newcommand{\conccol}[1]{{\MidnightBlue{#1}}} % concrete and steel color
\newcommand{\pdcol}[1]{{\OliveGreen{#1}}} % power density color (per area) same as powerd
\newcommand{\eccol}[1]{{\frcol{#1}}} % energy consumption in transport
\newcommand{\tempcol}[1]{{\DarkOrchid{#1}}} % temperature difference
\newcommand{\leakcol}[1]{{\MidnightBlue{#1}}} % leakiness
\newcommand{\effcol}[1]{{\OliveGreen{#1}}} % efficiency of heater
\newcommand{\modcol}[1]{{\Red{#1}}} % building modifications
\newcommand{\moneycol}[1]{{\DarkOrchid{#1}}} % money colour in planM.tex
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% \newcommand{\leakcol}[1]{{\DarkOrchid{#1}}} % leakiness defined later
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% CMYK \textColor{.2 .3 .4 .1}
% old
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%\newcommand{\nqs}[1]{\sl\Mahogany{#1}}%% I would like a dark red
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\newcommand{\nW}{}% null Watt symbol
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% \newcommand{\mile}{{\rm{mile}}}
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% ---- FRENCH ----
\def\naive{na\"{\i}ve}
\def\Naive{Na\"{\i}ve}
\def\naively{na\"{\i}vely} % Okay, I know, this isn't French.
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\def\cafe{caf\'e}
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% ---- PORTUGESE (Hi Jorge!) ----
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\def\abs#1{\mathopen| #1 \mathclose|} % use instead of $|x|$
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\def\indic#1{\big[#1\big]} % indicator variable; Iverson notation
% % e.g., Kronecker delta = [x=0]
% --- Self-scaling delmiter pairs ---
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% \input{/home/mackay/tex/newcommands2e}
% textcomp provides textdegree
% Alternatively, you could use: \newcommand{\degrees}{\ensuremath{^{\circ}}}%
%\title{Cause for Terror}
\title{
Sustainable Energy --- without the hot air
% You figure it out --
% {Sustainable energy on the back of an envelope}
% {The sustainable energy crisis on the back of an envelope}
}%
%\author{David J.C.\ MacKay}
\author{David JC MacKay}%
%\date{\today\ -- Prepublication draft \thedraft}
\date{}%
\shortauthor{David J.C. MacKay}%
% end of header2.tex
% insert version controls here
\setcounter{monoed}{0}% MONOCHROME!
%\setcounter{uked}{1}%
\setcounter{lowresed}{0}% HI RES!
%\setcounter{leveltwo}{0}% controls type of postscript
\setcounter{frompage}{0}% this is used by newcommands1.tex dvips operator that helps make
% individual chapters.
% extent: (414 + NMM 2) = 416 = 12 * 32
% next target: (382 + NMM 2)
% now at 370. What's next? 350. Or 366.
%
%The extra space is because we're working to 235mm * 0.95 = 223,
%but in fact we can go to 233mm
%\newpage
\thispagestyle{empty}%
\pagenumbering{roman}%
\setcounter{page}{0}%
\makezerotitle
\thispagestyle{empty}
\setcounter{page}{1}%
%\input{fluff.tex}% for first printing
% \fulltextwidth 178mm
\thispagestyle{empty}\noindent%
% Top scientists
% used to be....
%\raisebox{39pt}[119mm]{\begin{tabular}{@{}p{84.5mm}@{\hspace*{8mm}}p{84.5mm}}
% on Tue 7/4/09 changed to...
\raisebox{39pt}[119mm]{\hspace*{0.45mm}\begin{tabular}{@{}p{83.3mm}@{\hspace*{8mm}}p{83.3mm}}
% Green activists
% \begin{tabular}{@{}p{85mm}@{\hspace*{8mm}}p{85mm}}
\mywcquote{
The quest for safe, secure and sustainable energy poses one of the most
critical challenges of our age. But how much energy do we need, and can we
get it all from renewable sources? David MacKay sets out to find the answer
through a forensic numerical analysis of what we use and what we can
produce. His conclusions starkly reveal the difficult choices that must
urgently be taken and readers interested in how we will power our society in
the future will find this an illuminating read. For anyone with influence on
energy policy, whether in government, business or a campaign group, this
book should be compulsory reading. This is a technically precise and
readable account of the challenges ahead. It will be a core reference on my
shelf for many years to come.
}{Tony Juniper}{Former Executive Director, Friends of the Earth}%
% {author of {\em{How many lightbulbs does it take to change a planet?}}}
% \mywcquote{ }{Prof Martin Rees PRS}&
\mywcquote{
This is a really valuable contribution to the continuing
discussion of energy policy.
The author uses a potent mixture of
arithmetic and common sense to dispel some myths and slay some sacred
cows.
%In lay language he systematically analyses the whole gamut of
%energy sources, sustainable and less so, and assesses their potential.
%The book has a superb bibliography and is an essential reference work
%for anyone with an interest in energy that goes deeper than the Sunday
%newspapers and who really wants to understand the numbers.
The book
% \ldots\
is an essential reference work
for anyone with an interest in energy
% \ldots\
who really wants to understand the numbers.
}{
Lord Oxburgh KBE FRS}{
% Ron Oxburgh
Former Chairman, Royal Dutch Shell}
\mywccquote{
% The climate is changing, and scientists are clear about why this is so.
This remarkable book from an expert in the energy field sets out, with
enormous clarity and objectivity, the various alternative low-carbon
pathways that are open to us. Policy makers, researchers, private sector
decision makers, and NGOs, all will benefit from these words of wisdom.
}{Sir David King FRS}{
Chief Scientific Adviser}{ to the UK Government, 2000--08
}
\mywcquote{
Started reading your book yesterday. Took the day off work today so that I
could continue reading it. It is a fabulous, witty, no-nonsense, valuable
piece of work, and I am busy sending it to everyone I know.
}{Matthew Sullivan}{Carbon Advice Group Plc}
%
\mywcquote{A total delight to read.
Extraordinarily clear and engaging.}{Chris Goodall}{Author of {\em{Ten Technologies to Save the Planet}}}
&
%%%%%% TOP RIGHT new column
\mywcquote{``Sustainable Energy -- without the hot air" makes clear the science behind the headlines on energy issues. It is a fine guide for both experts and beginners.
}{Prof Daniel Kammen}{Co-Director, Berkeley Institute of the Environment}
%% Founding Director, Renewable and Appropriate Energy Laboratory, UC Berkeley
%
\mywcccquote{
MacKay's book shows how, when it comes to energy, you too can do the simple arithmetic and learn the simple scientific facts needed to work out what energy you need and where it might come from.
}{Prof David Mumford}{Professor of Applied Mathematics}{
Brown University}{Member of the US National Academy of Sciences}%
\mywcccquote{Common sense, technology literacy, and a little calculation go a long way in helping the reader sort sense from nonsense in the challenges of developing alternatives to fossil fuels. MacKay has provided a high priority book on a high priority problem.
}{Professor William W. Hogan}{
Raymond Plank Professor of Global Energy Policy}{
John F. Kennedy School of Government}{
Harvard University}%
\mywccccquote{%
%% David MacKay's book on sustainable energy
This is a complete resource for assessing the many options for choosing between different energy options and for using energy more efficiently. Teachers, students, and any intelligent citizen will find here all the tools needed to think intelligently about sustainability.
This is the most important book about applying science to public problems that I have read this year.
}{Prof Jerry Gollub}{
Professor of Physics, Haverford College}{and University of Pennsylvania}{
Member of the US National Academy of Sciences}{
}
\mywcquote{MacKay's book is the most practical, solidly analytical, and enjoyable book on energy that I have seen. This heroic work gets the energy story straight, assessing the constraints imposed by physical reality that we must work within. }{Prof Tom Murphy}{
Associate Professor of Physics,
UC San Diego}
\medskip
\hfill {\textbf{\em{continued on next page}}}
\\
% MP ZONE
\end{tabular}}
\newpage\thispagestyle{empty}
\noindent%
\begin{tabular}{@{}l}%
\hspace*{0.3mm}\begin{tabular}{@{}p{83.3mm}@{\hspace*{8mm}}p{83.3mm}}
\mywccquote{David MacKay's book
% ``Sustainable Energy without hot air"
is an
intellectually satisfying, refreshing contribution to really
understanding the complex issues of energy supply and use. It debunks
the emotional claptrap which passes for energy policy and puts real
numbers into the equations. It should be read by everyone, especially
politicians.
}{
Prof Ian Fells CBE}{
%former
Founder
chairman of NaREC,}{the New and Renewable Energy Centre}
\mywcquote{
Preventing climate chaos will require sophisticated and well informed
social, economic and technological choices. Economic and social
`laws' are not immutable -- politicians can and should reshape
economics to deliver renewable energy and lead cultural change to save
energy -- but MacKay reminds us that even they ``canna change the laws
of physics"! MacKay's book alone doesn't have all the answers, but it
provides a solid foundation to help us make well-informed choices, as
individuals and more importantly as societies.
}{Duncan McLaren}{Chief Executive, Friends of the Earth Scotland}
\mywccquote{
By focusing on the metrics of energy consumption and production, in addition to the aspiration
we all share for viable renewable energy, David MacKay's book provides a welcome addition to
the energy literature. ``Sustainable Energy -- without the hot air" is a vast undertaking that
provides both a practical guide and a reference manual. Perhaps ironically for a book on
sustainable energy, MacKay's account of the numbers illustrates just how challenging replacing
fossil fuel will be, and why both energy conservation and new energy technology are necessary.
}{
Darran Messem}{
Vice President Fuel Development}{
Royal Dutch Shell}
\mywcquote{
This is a must read for anyone who wants to help heal our world.
}{
Carol Atkinson}{Chief Executive of BRE Global}
% pacifists and academics
\mywcquote{
Beautifully clear and amazingly
readable.
%Amazingly readable
}{Prof Willy Brown CBE}
{
%% Montague Burton Professor of Industrial Relations
% Faculty of Economics, University of Cambridge
}
&
\mywccquote{
At last a book that comprehensively reveals the true facts about
sustainable energy in a form that is both highly readable and
entertaining.
% David MacKay's technique of simplifying the analysis in a
% step-by-step approach cuts through the ``twaddle" he refers to which is
% often used to confuse, misdirect and distort by many that know better
% and by others who should know better.
A ``must read" for all those who
have a part to play in addressing our climate crisis.
}{
Robert Sansom}{
Director of Strategy and Sustainable Development}{
EDF Energy}
% Energy expert zone
\mywccccquote{
So much has been written about meeting future energy needs that it hardly
seems possible to add anything useful, but David MacKay has managed it.
His new book is a delight to read and will appeal especially to practical
people who want to understand what is important in energy and what is not.
Like Lord Kelvin before him, Professor MacKay realises that in many fields,
and certainly in energy, unless you can quantify something you can never
properly understand it. As a result, his fascinating book is also a mine
of quantitative information for those of us who sometimes talk to our
friends about how we supply and use energy, now and in the future.
}{
Dr Derek Pooley CBE}{
Former Chief Scientist at the Department of
Energy,}{Chief Executive of the UK Atomic Energy Authority}{ and Member of the
European Union Advisory}{Group on Energy}
\mywccquote{The need to reduce our dependence on fossil fuels and to find
sustainable sources of energy is desperate. But much of the
discussion has not been based on data on how energy is consumed and
how it is produced. This book fills that need in an accessible form,
and a copy should be in every household.}{Prof Robert Hinde CBE FRS FBA}{
Executive Committee, Pugwash UK}{
Department of Zoology, University of Cambridge}
\mywcquote{
MacKay brings a welcome dose of common sense into the discussion of
energy sources and use. Fresh air replacing hot air.
}{
Prof Mike Ashby FRS}{
% , Engineer
% Cambridge Engineering Design Centre
% \par \hfill
Author of {\em{Materials and the environment}}}
\mywCquote{
I took it to the loo and almost didn't come out again.}%
{Matthew Moss}
% Secretary to the Vice-Chancellor,
%University of Cambridge
%{}
\\
\end{tabular}\\
\end{tabular}
\clearpage
\thispagestyle{empty}
\maketitle
\makededication
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\chapter*{Preface}
%\input{draft.tex}
% Promotional taglines: Carol Vorderman meets Freakonomics?
\noindent
\section*{What's this book about?}
I'm concerned about cutting UK emissions of twaddle
-- twaddle about sustainable energy.
Everyone says getting off fossil fuels is important,
and we're all encouraged
to ``make a difference,'' but many of the things that allegedly
make a difference don't add up.
% (For example, switching off mobile phone chargers.)
Twaddle emissions are high at the moment because people get emotional
(for example about wind farms or nuclear power) and no-one talks about numbers.
Or if they do mention numbers, they select them to sound big, to make an
impression, and to score points in arguments, rather than to aid
thoughtful discussion.
This is a straight-talking book about the numbers.
%The aim is to equip the reader with the facts needed for
%a discussion of energy, and
The aim is to guide the reader
around the claptrap to actions that really make a difference and to
policies that add up.
\section{This is a free book}
I didn't write this book to make money.
I wrote it because sustainable energy is important.
If you would like to have the book for free for your own use,
please help yourself:
it's on the internet at {\tt{www.withouthotair.com}}.
This is a free book in a second sense:
you are free to use {\em{all}\/} the material in this book,
{\em{except}\/} for the cartoons and the photos with a named
photographer, under the
Creative Commons Attribution-Non-Commercial-Share-Alike 2.0 UK: England \& Wales Licence.
(The cartoons and photos are excepted
because the authors have generally given me permission only to
include their work, {\em not\/} to share it under a
Creative Commons license.)
You are especially welcome to use
my materials for educational purposes.
My website includes separate high-quality files for each of the
figures in the book.
% Please don't propagate poor-quality
% copies of my diagrams when high quality ones are available.
% Most of the figures have numbered captions, but sometimes I try to
% avoid clutter by omitting captions -- for example, from maps.
\newpage
\thispagestyle{plain}
\section{How to operate this book}
\marginpar{
\begin{center}
\begin{tabular}{@{}c@{}}
%% \lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Machine2S.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Machine2.jpg.eps}}}%
\\
\end{tabular}
\end{center}\label{Claire7}
% \caption[a]{ }
}%
Some chapters begin with a quotation. Please don't assume that
my quoting someone means that I agree with them;
% because I quote someone it means I agree with them
think of these quotes as provocations, as hypotheses
to be critically assessed.
Many of the early chapters (numbered 1, 2, 3, \ldots)
have longer technical chapters (A, B, C, \ldots)
associated with them. These technical chapters start on
page \pageref{appA}.
At the end of each chapter are further notes
and pointers to sources and references.
I find footnote marks distracting if they litter
the main text of the book, so the book has no
footnote marks. If you love footnote marks,
you can usefully
add them -- almost every substantive assertion in the text will
have an associated note at the end of its chapter giving sources or
further information.
The text also contains pointers to web resources.
% At the end of a book
%% \writetheurls
% Where possible, I give URLs to web resources.
When a web-pointer\index{web pointer}
is monstrously long, I've used the TinyURL\index{tinyURL}
service, and put the tiny code in the text like this --
[\url{yh8xse}] -- and the full pointer at the end of the book
on page \pageref{urllist}.
\url{yh8xse} is
a shorthand for a tiny URL, in this case:
\url{http://tinyurl.com/yh8xse}.
%
A complete list of all the URLs in this book
is provided at
% \url{http://www.inference.phy.cam.ac.uk/sustainable/book/tex/cft.url.html}
% which you can get to using the tiny URL
\url{http://tinyurl.com/yh8xse}.
% The full-length URLs are listed on
% page \pageref{urllist}.
% See also
% \url{http://www.inference.phy.cam.ac.uk/sustainable/book/tex/cft.url.html}
% for a clickable page with all URLs in this book.
% An electronic version of this book is available for free
% on the website \myurl{www.withouthotair.com}.
% This book used to be longer. The removed material
% (roughly 100 pages on carbon, climate change,
% and the many strategies people use to try to mislead
% or to win arguments) is available in draft form
% on the same website.
I welcome feedback and corrections.
I am aware that I sometimes make booboos, and in earlier
drafts of this book some of my numbers were off by a factor of two.
While I hope that the errors that remain are smaller than that,
I expect to further update some of the numbers in this book
as I continue to learn about sustainable energy.
How to cite this book:
% \nocite{WithoutHotAir}.
\begin{description}
\item[David~J.C. MacKay.]
\newblock \emph{Sustainable Energy -- without the hot air}.\\
\newblock UIT Cambridge, 2008.
\newblock ISBN 978-0-9544529-3-3.
\newblock Available free online from \url{www.withouthotair.com}.
\end{description}
\newpage
%% energy police
\mytableofcontents
\clearpage
\dvipsb{table of contents}
\dvipsspecial{1}% set the page to 1 (normally forbidden)
\thispagestyle{empty}
% SEWTHA some basic numbers
\cleardoublepage
%\clearpage
%\thispagestyle{empty}
% \input{favourite.tex}
%\clearpage
\pagenumbering{arabic}
\setcounter{page}{1} % set to current value
\bset\part{\bcol{Numbers, not adjectives}}\label{pone}
%\subchaptercontents
\bset\chapter{\bcol{Motivations}}
\label{ch.preface}
\myquote%
{We live at a time when emotions and feelings count more
than truth, and there is a vast ignorance of science.}
{\index{Lovelock, James}{James Lovelock}}
%\end{quote}
\marginfignocaption{
%\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=35mm\epsfbox{../../images/OutOfGas.eps}} \\[6pt]
%\mbox{\epsfxsize=50mm\epsfbox{../../images/OutOfGasBig.eps}} \\
%\mbox{\epsfxsize=35mm\epsfbox{../../solar/images/lomborgSE.ps}}\\
\end{tabular}
\end{center}
%\caption[a]
{David Goodstein's
{\em Out of Gas} (2004).\nocite{Goodstein2004}
% have asked for permissions from http://www.wwnorton.com/
% and
% http://www.cambridge.org/uk/information/rights/forms/permission.htm
}
}%
\marginfignocaption{
%\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
%\mbox{\epsfxsize=35mm\epsfbox{../../images/OutOfGas.eps}} \\[12pt]
%\mbox{\epsfxsize=50mm\epsfbox{../../images/OutOfGasBig.eps}} \\
\mbox{\epsfxsize=35mm\epsfbox{../../solar/images/lomborgSE.ps}}\\[6pt]
\end{tabular}
\end{center}
%\caption[a]
{
{Bj{\o}rn Lomborg}'s {\em{The Skeptical Environmentalist}\/}
(2001).\nocite{Lomborg2001}
% have asked for permissions from http://www.wwnorton.com/
% and
% http://www.cambridge.org/uk/information/rights/forms/permission.htm
}
}%
I recently read two books, one by a physicist, and one by
an \ind{economist}. In {\em\ind{Out of Gas}}, \ind{Caltech} \ind{physicist}
{David Goodstein}\index{Goodstein, David} describes an impending energy crisis
brought on by The
End of the Age of Oil.
% end of the age of oil.
This crisis\index{peak oil}
is coming soon, he predicts: the crisis will bite, not when the last
drop of oil is extracted, but when oil extraction can't meet demand
-- perhaps as soon as 2015 or 2025. Moreover, even if we magically
switched all our energy-guzzling to \ind{nuclear power}\index{peak nuclear}
right away, Goodstein says, the oil crisis would simply be replaced by a
{\em nuclear\/}
% {\em Uranium\/}
crisis in just twenty years or so,
as \index{uranium!reserves}{uranium reserves} also became depleted.
In {\em\ind{The Skeptical Environmentalist}},
{Bj{\o}rn Lomborg}\index{Lomborg, Bj{\o}rn}
paints a completely different picture. ``Everything is fine.''
Indeed,
``everything is getting better.''
Furthermore, ``we are not headed for a major energy crisis,'' and
``there is plenty of energy.''
How could two smart people come to such different conclusions?
I had to get to the bottom of this.
%\medskip
Energy made it into the British
% U.K.\
news in 2006. Kindled by tidings of
great climate change and a tripling in the price
of natural gas in just six years, the flames of debate are raging.
How should Britain
% the U.K.\
handle its energy needs?
And how should the world?
``Wind or nuclear?'', for example.
Greater polarization of views among smart people is hard to imagine.
During a discussion of
% the prospect of
the proposed expansion of nuclear power,
% see quotes
% http://www.bbc.co.uk/radio4/news/anyquestions_transcripts_20060127.shtml
Michael Meacher, former environment minister,
%% from 1997 till 2003
said\label{pageANYQ}
% see notes at end
``if we're going to cut
greenhouse gases by 60\% \ldots\
%% , as you rightly say,
by 2050 there is no
other possible way of doing that except through renewables;''
Sir Bernard Ingham, former civil servant,
speaking in favour of nuclear expansion,
said
%% ``It's a dream world'' and
``anybody who is relying upon
renewables to fill the [energy] gap is living in an utter dream
world and is, in my view, an enemy of the people.''
% Strong stuff!
Similar disagreement can be heard within the ecological movement.
All agree that {\em{something}\/} must be done urgently, but {\em{what?}}
Jonathon Porritt, chair of the \ind{Sustainable Development Commission},
% advises that
writes:\label{pagePorritt}\index{Porritt, Jonathon}
``there is no justification for bringing forward plans
for a new nuclear power programme at this time, and
%%% that
\ldots\
any such proposal would be incompatible with [the Government's]
sustainable development strategy;'' and
``a non-nuclear strategy could and should be sufficient to deliver
all the carbon savings we shall need up to 2050 and beyond,
and to ensure secure access to reliable sources of energy.''
\marginfignocaption{
\begin{center}
\begin{tabular}{@{}c@{}}
%% permission granted Wed 23/7/08
\mbox{\epsfxsize=35mm\epsfbox{../../images/revengeOfGaia.eps}} \\[6pt]
%\mbox{\epsfxsize=50mm\epsfbox{../../images/James_Lovelock.eps}} \\
\end{tabular}
\end{center}
%\caption[a]
{
{\em The Revenge of \ind{Gaia}:\index{Lovelock, James}
Why the earth is fighting back -- and how we can still save humanity.}
James Lovelock (2006). \copyright\ Allen Lane.
% Sent request to adultpermissions@penguin.co.uk
%% Photograph of James Lovelock with statue of Gaia. \copyright\ Comby Institute \url{www.comby.org}
%% Contacted The Institute they were happy for it to be used on wikipedia Fair Use of a Publicity Photo
%% http://en.wikipedia.org/wiki/Image:James_Lovelock.jpg
}
}%
In contrast,
% Prof.\ James Lovelock FRS,
environmentalist James Lovelock
% ``the founding historical and cultural
% leader of environmentalism''\label{pageLovelock}
% for environmentalists around the world.
% knocks both ``sustainable development'' and ``business as
% usual''
writes in his book, {\em The Revenge of Gaia}:
``Now is much too late to establish sustainable development.''
In his view, power from nuclear fission, while not recommended
as the long-term panacea for our ailing planet,
is ``the only effective medicine we have now.''
Onshore wind turbines are ``merely \ldots\ a gesture to
prove [our leaders'] environmental credentials.''
\medskip% BREATH
% recently removed section heading
% \section{Numbers, not adjectives}
This heated debate is fundamentally about numbers.
How much energy could each source deliver,
at what economic and social cost,
and with what risks? But actual numbers are
rarely mentioned. In public debates, people just say
% things like
% Ann Leslie said this (quotes)
% Malcolm Wicks, Minister for Energy, said (or was it another?)
% (Any Questions 11 Feb 2006 CHECK) Ann Leslie
``Nuclear is a money pit''
or
% Ann Leslie said this (quotes)
``We have a {\em{huge}\/} amount of wave and wind.''\label{AnnLeslie}
The trouble with this sort of language is that it's not
sufficient to know that something is huge: we need to know
how the one ``huge'' compares with another ``huge,'' namely {\em our huge
energy consumption}.
To make this comparison, we need numbers, not adjectives.
%
% NUMBERS, NOT ADJECTIVES
% Abundant and inexhaustible
Where numbers are used, their meaning is
% all too
often obfuscated by enormousness. Numbers are chosen to impress,
to score points in arguments, rather than to inform.
``\ind{Los Angeles} residents drive 142 million miles -- the distance from
Earth to Mars -- every single day.''\label{pageLA}
%% from page 34 of ``50 Simple THings You can do to save the earth''
% `Americans produce enough styrofoam cups
% every year to circle the earth 436 times'.
%% from page 44 of ``50 Simple THings You can do to save the earth''
% `Americans throw away 18 billion disposable diapers a year --
% enough to stretch to the moon and back seven times'.
%% from page 68 of ``50 Simple THings You can do to save the earth''
% `Every year, Americans throw away enough paper
% to build a wall 12 feet high, stretching from Los Angeles
% to New York City'.
%% from page 70 of ``50 Simple THings You can do to save the earth''
% `Americans produce 154 million tons of garbage every year --
% enough to fill the New Orleans Superdome from top to bottom, twice
% a day, every day'. [Why not from bottom to top?]
%% from page 72 of ``50 Simple THings You can do to save the earth''
``Each year, 27 million acres of tropical rainforest are destroyed.''
%% from page 74 of ``50 Simple THings You can do to save the earth''
``14 billion pounds of trash are dumped into the sea every year.''
%% from page 13 of ``50 Simple THings You can do to save the earth''
%% @book{FiftySimple,
%% title={50 Simple Things You Can Do to Save the Earth},
%% author={The Earth works Group},
%% publisher={The Earthworks Press},
%% address={Berkeley, California},
%% ISBN={0-929634-06-3}, year={1989}
%% }
% ``Using electricity to heat UK homes, instead of directly burning gas,
% wastes 280\,TWh of energy -- enough to boil a body of water 9 times the
% volume of Lake Windermere (2\,304\,000\,000 cubic metres)!''
``British people throw away 2.6 billion slices of bread per year.''
% source http://news.bbc.co.uk/1/shared/bsp/hi/pdfs/foodwewaste_fullreport08_05_08.pdf
%% \cite{FoodWaste}
``The waste \ind{paper} buried each year in the UK could fill 103\,448
\ind{double-decker bus}es.''
% ``Use a water-saving shower head and save 70\,000 litres of water over a decade.''
% www.greenbuildingstore.co.uk
If all the ineffective ideas for solving the energy crisis
were laid end to end, they would reach to the moon and back\ldots.
I digress.
The result of this lack of meaningful numbers and facts?
We are inundated with a flood of crazy innumerate codswallop.
% {\em [POLISHING WORK NEEDED HERE] }
The BBC doles out advice on how we can do our bit to
save the planet --
for example ``switch off your mobile phone charger
when it's not in use;'' if anyone objects that mobile phone chargers
are not {\em{actually}\/}
our number one form of energy consumption,
% ***
\amarginfignocaption{t}{\small
For the benefit of readers who speak American, rather than English,
the translation of ``every little helps'' into American is
``every little bit helps.''}%
% ***
the mantra ``\ind{every little helps}'' is wheeled out.
Every little helps?
% I'm sure some people realise a
A more realistic mantra is:
\begin{oldcenter}
{\em if everyone does a little, we'll
achieve only a little}.
\end{oldcenter}
%%If everyone does a little,
%%you'll get a little
Companies also contribute to the daily codswallop as
they tell us how wonderful they are, or how they can help
us ``do our bit.''\index{do your bit} \ind{BP}'s website,
for example,
% boasts that
% ``BP's advanced multigrade and synthetic lubricants
% are helping to reduce emissions of \COO\ by improving
% vehicle efficiency. A study in India estimated that the
% use of BP's multigrade lubricants by heavy goods vehicles
% in India reduced emissions by
% 0.8 million \tonnes\ \COO\ per year.''
% Now, that number itself is not codswallop, but if readers
% get the impression that this is a {\em{huge}\/}
% reduction, then BP have misled them.\label{pageBPmisled} Their
% website also
celebrates the reductions in
% \COO\
carbon dioxide (\COO)
pollution
they hope to achieve by changing the paint\index{ship!painting}
used for painting BP's ships.
Does anyone fall for this? Surely everyone will guess that it's
not the exterior paint job, it's
the stuff {\em inside\/} the tanker that
% BP is selling
deserves attention, if society's \COO\ emissions are to be
significantly cut?
BP also created a web-based carbon \ind{absolution} service,\index{offsetting}\index{carbon offset}\index{carbon neutralization}\index{neutralization, carbon}\index{myth!offsetting}
``\url{targetneutral.com},''\label{ptarget} which claims that they can ``neutralize''
all your carbon emissions, and that it ``doesn't cost the earth'' -- indeed,
that your \COO\ pollution can be cleaned up
for just \pounds40 per year.
% 4 pounds per ton of CO2 -- so 10 tons = 40 pounds
% On average its just £20 a year.
% This has to be a scam
How can this add up?
-- if
% climate change really is a problem,
% and radical change is required, how could
% a payment of just \pounds 40 per person make the problem go away?
% If this
the true cost of fixing climate change
were \pounds 40 per person
then the government
could fix it with the loose change in the \uk{\ind{Chancellor}}{{taxman}}'s pocket!\index{taxman}
%%% REDUCE THE BP RANT AND INSERT A POWERGEN GREEN TARRIF RANT?
Even more reprehensible are companies that exploit the current
concern for the environment by offering
``water-powered batteries,''
``biodegradable mobile phones,''
% http://news.bbc.co.uk/1/hi/england/coventry_warwickshire/4056687.stm
% http://www.hippyshopper.com/2005/12/biodegradable_p.html
% http://www.gearcrave.com/buyers-guide/features/news-features/linkcrave-biodegradable-mobile-phones-and-more/
``portable arm-mounted wind-turbines,''
% ``envi\-ron\-ment-friendly phone calls,''
and other pointless tat.
Campaigners also mislead.\index{presentation, misleading}
People who want to promote renewables
over nuclear,\index{nuclear power} for example, say ``offshore wind power
% renewables
could power all UK homes;''\nlabel{windNuke4}
% supply 80\% of our electricity'';
% \ldots
then they say
``new nuclear power stations
will do little to tackle climate change''
because 10 new nuclear stations would
``reduce emissions only by about 4\%.''
% nuclear power would only reduce our emissions by \ldots''
This argument is misleading because the playing field\index{magic playing field}
is switched half-way through, from the ``number of \ind{home}s powered''
to ``reduction of emissions.''
% Whenever the ``home'' is used
% as a measure of power, I suspect someone is being misled!
The truth is that the
amount of electrical power generated by the wonderful windmills
that
``could power all UK homes'' is {\em{exactly the same}\/} as
the amount that would be generated by the 10
% pathetic
nuclear power stations!
% that would
% ``reduce emissions only by about 4\%''!
``Powering all UK homes'' accounts for just 4\% of UK emissions.
Perhaps the worst offenders in the kingdom of
codswallop are the people who really should know
better -- the media publishers who
% devote pages
% to the
promote the codswallop -- for example,
% . A couple that spring to mind:
\ind{New Scientist} with their article about the
``water-powered car.''\Mahogany{$^*$}%
\amarginfignocaption{t}{
\small\raggedright
\Mahogany{$^*$}See this chapter's
notes (\pref{pnWaterCar}) for the awful details.
(Every chapter has endnotes giving references, sources, and
details of arguments.
To avoid distracting the reader, I won't include any more footnote marks
in the text.)
}\label{pageWaterCar}
In a climate where people don't understand the \ind{numbers},
newspapers, campaigners, companies, and politicians can get away with murder.
%\medskip% BREATH
%%% INSERT ``Motivations'' here?
% recently removed section heading
%\section{Meaningful numbers} factual
We need simple numbers, and we need the numbers to be comprehensible,
comparable, and memorable.
With numbers in place, we will be better placed to answer
questions such as these:
\begin{enumerate}
%\item is there an urgent need to reduce car travel
\item
Can a country like Britain conceivably
live on its own renewable energy sources?
\item
If everyone turns their \ind{thermostat}s one degree closer to the
outside temperature, drives a smaller car, and switches off
\ind{phone charger}s when not in use, will an energy crisis be averted?
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=52mm\epsfbox{../../images/LoveHateS.eps}}%
{\epsfxsize=52mm\epsfbox{../../images/LoveHate.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
This \ind{Greenpeace} leaflet arrived with my \ind{junk mail}
in May 2006. Do beloved windmills have the capacity
to displace hated cooling towers?\index{love}\index{hate}
}
\label{lovehate}
}%
\item
Should
the tax on transportation fuels be significantly increased? Should speed-limits
on roads be halved?
\item
Is someone who advocates windmills
over nuclear power stations ``an \ind{enemy of the people}''?
\item
If climate change is ``a greater threat than \ind{terrorism},''\label{pageDK}
should governments criminalize\index{climate change!greater threat than terrorism}
% pass legislation that makes `the glorification of travel' a crime?
``the \ind{glorification of travel}'' and
pass laws against
``\ind{advocating acts of consumption}''?\label{pageglory}
\item
Will a switch to ``advanced technologies'' allow us to
eliminate carbon dioxide pollution without changing our lifestyle?
\item
Should people be encouraged to eat more \ind{vegetarian} food?
\item
Is the population of the earth six times too big?\index{population reduction}
\end{enumerate}
%%% INSERT MOTIVATIONS HERE? then Whatever your motivation, ....
\section{Why are we discussing energy policy?}
\label{sec.why}
Three different motivations drive today's energy discussions.\index{motivations}
% worries.
\amarginfig{b}{
\begin{center}
\mbox{\epsfxsize=53mm%
{\epsfbox{../data/eia/NorthSOprice.eps}}%
}%
\\[0in]
\end{center}
\caption[a]{Are ``our'' fossil fuels running out?
Total {crude oil production}\index{crude oil!production} from the North Sea,\index{North Sea!oil}
and oil price
in 2006 dollars per barrel.\index{oil!price}\index{oil!North Sea}\index{data!oil price}\index{data!oil production}
% http://www.bp.com/productlanding.do?categoryId=6848&contentId=7033471
}\label{fig.NorthSO}
%fixed label error Mon 6/10/08
}%
First, \ind{fossil fuels} are a finite resource. It seems possible
that cheap oil (on which our cars and \uk{lorries}{trucks} run) and
cheap gas (with which we heat many of our buildings) will run out in
our lifetime. So we seek alternative energy sources. Indeed given
that fossil fuels are a valuable resource, useful for manufacture of
plastics and all sorts of other creative stuff, perhaps we should
save them for better uses than simply setting fire to them.
Second, we're interested in \ind{security of energy supply}.
Even if fossil fuels are
still
available somewhere in the
world, perhaps we don't want to depend on them if that
would make our economy vulnerable to the whims of
\ind{untrustworthy foreigners}\index{foreigners}.
(I hope you can hear my tongue in my cheek.)\index{fossil fuels!peaking of}
Going by \figref{fig.NorthSO},
it certainly looks as if ``our'' fossil fuels have peaked.\index{peak oil}
The UK has a particular security-of-supply problem looming,
known as the ``\ind{energy gap}.'' A substantial number of
old \ind{coal power station}s\index{power station!closures}\index{oil power stations} and%
\marginfig{
\begin{center}
\mbox{\epsfxsize=53mm\epsfbox{../data/EdFGap.eps}} \\
\end{center}
\caption[a]{The \ind{energy gap} created by UK \ind{power station} closures,
as projected by energy company \ind{EdF}.
This graph shows the predicted capacity of nuclear, coal, and oil
power stations, in kilowatt-hours per day per person.
The capacity is the maximum deliverable power of a source.
% This graph shows the % in kWh per day per person.
% and there's imports too. from france
}
\label{fig.Gap}
}
\index{nuclear!power station closures}{nuclear power stations}\index{data!power station closures}
will be closing down during the next decade
(\figref{fig.Gap}),
so there is a risk that electricity demand will sometimes exceed
electricity supply,\index{electricity!supply!energy gap}
if adequate plans are not implemented.
% At the same time, Britain's \ind{North Sea} fossil fuel supply is dwindling.
Third, it's very probable that
using fossil fuels changes the climate.\index{climate change}
Climate change is blamed on several human activities, but
the biggest contributor to climate change is the increase
in greenhouse effect produced
by carbon dioxide (\COO). Most of the carbon dioxide emissions come
from fossil-fuel burning. And the main reason we burn fossil fuels is
for energy.\index{greenhouse gas emissions}
So to fix climate change, we need to sort out a new way of getting energy.
The climate problem is mostly an energy problem.\index{climate change!is about energy}
% You don't have to believe in climate change to find
% this book useful.
Whichever of these three concerns motivates you,
we need energy numbers, and policies that add up.
The first two concerns are straightforward selfish motivations
for drastically reducing fossil fuel use. The\index{altruism}
third concern, climate change, is a more altruistic motivation -- the
brunt of climate change will be borne not by us
but by future generations over many
hundreds of years. Some people feel that climate change is not their
responsibility. They say things like ``What's the point
in my doing anything?
\ind{China}'s out of control!''
% And they're encouraged in this attitude by
% reprehensible journalists who peddle Dominic Lawson
So I'm going to discuss climate change a
bit more now, because while writing this book I learned some
interesting facts that shed light on these ethical questions.
If you have no interest in climate change, feel free to fast-forward
to the next section on page \pageref{rejoinHere}.
\section{The climate-change motivation}
The climate-change motivation\index{climate change} is argued in three steps:
one: human fossil-fuel burning causes carbon dioxide concentrations to
rise; two: carbon dioxide is a greenhouse
gas;\index{greenhouse effect}\index{carbon dioxide!greenhouse effect}\index{carbon dioxide!climate change}
three: increasing the greenhouse effect increases average global temperatures (and
has many other effects).
\begin{figure}
\figuremargin{
\begin{tabular}{@{}c@{}}%
\mono
{\epsfxsize=115.59mm\epsfbox{../../refs/carbon/mono/lawdome0.eps}}%
{\epsfxsize=115.59mm\epsfbox{../../refs/carbon/lawdome0.eps}}%
\\
\end{tabular}
}{
\caption[a]{Carbon dioxide\index{data!CO$_2$ concentrations}
(\COO) concentrations (in parts per million)\index{carbon dioxide!data}
for the last 1100 years, measured
from air trapped in \ind{ice cores} (up to 1977)
and directly in \ind{Hawaii} (from 1958 onwards).\smallskip
\par
I think {{something new}} may have happened between 1800\,AD and 2000\,AD.
I've marked the year 1769, in which James Watt\index{Watt, James}
patented his
\ind{steam engine}.
(The first practical
steam engine was invented 70 years earlier in 1698,
but Watt's was much more efficient.)
}
\label{fig.co2graph0}
}
\end{figure}
% Another, more local, thought. Log scale is not the
%way to get the message across. At least once, in the
%beginning, you should devote a whole page to a picture of
%an exp graph and emphasize that it blows up so fast that
%we would need to stretch the space 10m above the page, etc.
%Nowadays even science graduates cannot be trusted to have
%an instinctive appreciation of what log scale means.
We start with the fact that carbon dioxide
% (\COO)
concentrations are rising.
% The upper graph in
\Figref{fig.co2graph0} shows measurements of the
\COO\ concentration in the air from the year 1000\,AD to the present.
Some ``\ind{sceptic}s'' have asserted that the recent increase in \COO\ concentration
is a natural phenomenon.
%\begin{figure}
\marginfig{
\begin{center}
{\epsfxsize=53mm\epsfbox{../../data/EnglandL5a.eps}}%
% England.gnulps3, not
% England.gnulps2
\\
\end{center}
% }{
\caption[a]{
The history of\index{data!coal production}\index{data!oil production}
\ind{UK coal} production and \ind{world coal}
production from 1600 to 1910. Production
rates are shown in billions of
tons of \COO\ -- an incomprehensible unit, yes, but don't worry: we'll
personalize it shortly.
}
\label{fig.England5a}
}%
% See data/AllEmissions for total emissions and the calculation
% of 160ppm (emitted) and 97ppm (detected)
% caused by solar activity.
Does ``sceptic'' mean ``a person who has not even glanced at the data''?
% Just look: from 900\,AD to 1700\,AD, \COO\ concentrations never strayed
% outside the range $280\pm10$\,ppm. In 2004, the \COO\ concentration
% reached 377\,ppm.
%% http://cdiac.ornl.gov/pns/current_ghg.html
Don't you think, just possibly,
{\em{something}\/} may have happened between 1800\,AD and 2000\,AD?
Something that was not part of the natural processes present in the
preceding thousand years?
Something did happen, and it was called the \ind{Industrial Revolution}.
I've marked on the graph the year \ind{1769},
in which \index{Watt, James}{James Watt} patented his
\ind{steam engine}.
While the first practical steam engine was invented in \ind{1698},\nlabel{pHero}
Watt's more efficient steam engine really got the Industrial Revolution
going.
One of the steam engine's
main applications was the pumping of water out of coal mines.
\Figref{fig.England5a}
shows what happened to British \ind{coal production}
from 1769 onwards.
The figure displays coal production in units of billions of tons of \COO\
released when the coal was burned.
% 19cm * 34/4.8
In 1800, coal was used to make iron, to make ships, to heat buildings,
to power locomotives and other machinery, and of course to power the pumps that
enabled still more coal to be scraped up from
% deep
inside the hills of England and Wales.
Britain was terribly well endowed with coal:
when the Revolution started, the amount of carbon sitting in coal under
Britain was\index{coal!British resource}
roughly the same as the amount sitting in oil under \ind{Saudi Arabia}.
%%% England plot uses England.gnups data is in England
In the 30 years from 1769 to 1800, Britain's annual coal production doubled.
After another 30 years (1830), it had doubled again.
% , and the rate of
% growth itself increased:
The next doubling of production-rate
happened within {\em{20}\/} years (1850), and another doubling
within 20 years of that (1870).
% 1769est: 7.8 1800: 15 Mt 1830: 30 1850: 63 1870: 116 15-fold increase
This coal allowed Britain to turn the globe pink.
The prosperity that came to England and Wales was reflected in a century of
unprecedented \ind{population growth}:%
% , as \figref{fig.EnglandL1}
% the third graph in \figref{fig.co2graph} shows.
\index{world coal production}\index{population growth}
\medskip\\
\begin{center}
% as shown in \figref{fig.England3};
{\epsfxsize=115mm\epsfbox{../../data/EnglandL8a.eps}}%
\label{PopGrow}\medskip\\
\end{center}
% This rate of population growth may have been impressive, but the
% rate at which \ind{coal production}
% grew was even greater. As the middle graph
% shows, British coal production, which was essentially
% the same thing as \ind{world coal production}, doubled every 20 years.
\noindent Eventually other countries got in on the act too
as the Revolution spread.
\marginfig{
{\epsfxsize=53mm\epsfbox{../../data/EnglandL5b.eps}}%
\\
% }{
\caption[a]{
What happened next.
\smallskip\par
The history of\index{data!coal production}\index{data!oil production}
\ind{UK coal} production and \ind{world coal}
production from 1650 to 1960, on the same scale as
\protect\figref{fig.England5a}.
}
\label{fig.England5b}
%% gnuplot < England.gnulps
}%
% The middle graph
Figure \ref{fig.England5b} shows British coal production
and world coal production on the same scale as
\figref{fig.England5a}, sliding the window of history
50 years later.
British coal production peaked in \ind{1910}, but meanwhile
world coal production continued to double every 20 years.
It's difficult to show the history of coal production on a
single graph.
To show what happened in the {\em{next}\/} 50 years on the same scale,
the book would need to be one metre tall!
% scaled down
% 135cm 4.4 feet
To cope with this difficulty,
we can either scale down the vertical axis:\medskip\\
\begin{center}
% as shown in \figref{fig.England3};
{\epsfxsize=115mm\epsfbox{../../data/EnglandL8b.eps}}%
\medskip\\
\end{center}
\noindent
or we can squish the vertical axis in a non-uniform
way, so that small quantities and large quantities
can be seen at the same time on a single graph.
A good way to
squish the axis is called a \ind{logarithmic scale}, and that's what I've
used in the bottom two graphs of \figref{fig.co2graph}
(\pref{fig.co2graph}).
On a logarithmic scale, all ten-fold increases
(from 1 to 10, from 10 to 100, from 100 to 1000)
are represented by equal distances on the page.
On a logarithmic scale, a quantity that grows at a constant
percentage per year (which is called ``exponential growth'')
% doubles every 20 years
looks like a straight line. Logarithmic
graphs are great for understanding growth.
% ing quantities.
%\newpage%pagebreak[4]
\begin{figure}[htbp]
\figuremargin{
\hspace*{-4mm}%
\begin{tabular}{@{}c@{\hspace*{4mm}}}
\mono
{\epsfxsize=105.59mm\epsfbox{../../refs/carbon/mono/lawdome.eps}}%
{\epsfxsize=105.59mm\epsfbox{../../refs/carbon/lawdome.eps}}%
\\
\mono%
{\epsfxsize=105.59mm\epsfbox{../../data/mono/England.eps}}%
{\epsfxsize=105.59mm\epsfbox{../../data/England.eps}}%
\\
\end{tabular}
}{
\caption[a]{The upper graph shows carbon dioxide\index{data!CO$_2$ concentrations}
(\COO) concentrations (in parts per million)\index{carbon dioxide!data}
for the last 1100 years -- the same data that
was shown in \figref{fig.co2graph0}.\index{Watt, James}
\medskip
Here's a portrait of James Watt and his 1769
\ind{steam engine}.
% (The first practical
% steam engine was invented seventy years earlier in 1698,
% but Watt's was much more efficient.)
\medskip
\par
\begin{tabular}{@{}c@{}c@{}}
\lowres%
{\mbox{\epsfysize=26mm\epsfbox{../../images/JamesWattMedalFront1s.eps}}}%
{\mbox{\epsfysize=26mm\epsfbox{../../images/JamesWattMedalFront1.eps}}}%
&
\lowres%
{\mbox{\epsfysize=26mm\epsfbox{../../images/JamesWattMedalReverses.eps}}}%
{\mbox{\epsfysize=26mm\epsfbox{../../images/JamesWattMedalReverse.eps}}}%
\\
\end{tabular}
\medskip
\par
The middle graph shows (on a \ind{logarithmic scale}) the
history of\index{data!coal production}\index{data!oil production}
\ind{UK coal} production, \ind{Saudi oil} production, \ind{world coal}
production, world
oil production, and (by the top right point) the total of all greenhouse gas
emissions\index{greenhouse gas emissions} in the year 2000. All production rates
are expressed in units of the associated \COO\ emissions.\index{data!greenhouse gas emissions}
% All these production
% rates are shown in billions of
% tons of \COO\ -- an incomprehensible unit, yes, but don't worry: we'll
% personalize it shortly.
\medskip
\par
The bottom graph shows (on a logarithmic scale) some consequences
of the \ind{Industrial Revolution}: sharp increases in the
population of England,\index{population growth} and, in due course,
the world; and\index{data!population}
remarkable growth in
British \ind{pig-iron} production (in thousand tons per year);
and growth in the tonnage of British \ind{ship}s (in thousand tons).
\medskip
\par
In contrast to the ordinary graphs on the previous pages,
% \figref{fig.England3},
the logarithmic scale allows us to show both the population
of England and the population of the World on a single diagram,
and to see interesting
features in both.
}
\label{fig.co2graph}
\label{England}
\label{figKeeling}
}
\end{figure}
Whereas the ordinary graphs in the figures
on pages \pageref{fig.England5a}
% , \pageref{fig.England5b},
and \pageref{PopGrow} convey the messages that British and world
coal production grew remarkably, and that British and
world population grew remarkably, the relative growth rates
are not evident in these ordinary graphs. The logarithmic graphs
allow us to compare growth rates. Looking at the slopes of
the population curves, for example, we can see that the
world population's growth rate in the last 50 years
was a little bigger than the growth rate of England and Wales in 1800.
From 1769 to 2006, world annual coal production increased 800-fold.
Coal production is still increasing today.
% , a doubling that continued for a total of two hundred years.
%% world coal to 1913 in WorldCoal.txt and in SaudiOil.txt 2006: (7.33 / 3.6)*3.08=6200Mt
Other fossil fuels are being extracted too --
% \figref{fig.England3}
% the middle graph
% in
% and
the middle graph of
\figref{fig.co2graph} shows oil production for example -- but in terms of
\COO\ emissions, \ind{coal} is still king.\index{king coal}
The burning of fossil fuels is the principal reason why \COO\ concentrations
have gone up.
This is a fact, but, hang on:
% , do you hear what I hear?
I hear a persistent
buzzing noise coming from a bunch of
\ind{climate-change inactivists}.\index{sceptic}\index{inactivist}
% self-styled \ind{sceptics}.
What are they saying?
% Let's listen in on one.
Here's \index{Lawson, Dominic}{Dominic Lawson},\label{pSceptic}
a columnist from
the {\em\ind{Independent}}:
\begin{quote}
``The burning of fossil fuels sends
about \Red{seven \gigatonnes} of \COO\ per year into the atmosphere,
which sounds like a lot. Yet
the biosphere and the oceans send about
\OliveGreen{1900 \gigatonnes} and \MidnightBlue{36\,000 \gigatonnes}
of \COO\ per year into the atmosphere -- \ldots\ one reason why
some of us are sceptical about the emphasis put on the role
of human fuel-burning in the greenhouse gas effect. Reducing
man-made \COO\ emissions\index{greenhouse gas emissions}
is megalomania, exaggerating man's significance.
Politicians can't change the weather.''
\end{quote}
Now I have a lot of time for scepticism, and
not everything that sceptics say is a
\ind{crock of manure}\index{manure}\index{journalism, bad}
-- but \ind{irresponsible journalism} like
{Dominic Lawson}'s deserves a good flushing.
The first problem with Lawson's offering is that
{\em{all three numbers}\/} that he mentions (\Red{seven},
\OliveGreen{1900}, and \MidnightBlue{36\,000}) are {\em{wrong!}}
The correct numbers are
% \Red{7}, \OliveGreen{120}, and \MidnightBlue{90}. GtC
\Red{26}, \OliveGreen{440}, and \MidnightBlue{330}.
Leaving these errors to one side, let's address Lawson's main point,
the relative smallness of man-made emissions.
Yes, natural flows of \COO\ {\em{are}\/} larger than the
additional flow we switched on 200 years ago when we started
burning fossil fuels in earnest. But it is terribly misleading to
quantify only the large natural flows {\em{into}\/} the atmosphere,\index{greenhouse gas emissions!natural}
failing to mention the almost exactly equal flows {\em{out}\/} of the
atmosphere back into the biosphere and the oceans. The point is
that these {\em{natural}\/} flows in and out of the atmosphere
have been almost exactly in balance for millenia. So it's not
relevant at all that these natural flows are larger than human
emissions. The natural flows {\em{cancelled themselves out}}. So the
natural flows, large though they were, left the concentration of
\COO\ in the atmosphere and ocean {\em{constant}}, over the last
few thousand years. Burning fossil
fuels, in contrast, creates a {\em{new}\/} flow of carbon that,
though small, is {\em{not
cancelled}}.
Here's a simple analogy, set in
the passport-control arrivals
area of an airport. One thousand passengers
arrive per hour, and there are exactly enough clockwork officials
to process \MidnightBlue{one thousand passengers per hour}. There's a modest
queue, but because of the match of arrival rate to service rate,
the queue isn't getting any longer. Now imagine that owing to fog
an extra stream of flights is diverted here from a smaller
airport. This stream adds an extra \Red{50 passengers per hour}
to the arrivals lobby -- a small addition compared to the
original arrival rate of one thousand per hour.
Initially at least, the authorities don't
increase the number of officials, and the officials carry on processing just
one thousand passengers per hour. So what happens? Slowly but
surely, {\em the queue grows}.
% a supermarket where
% one thousand f day when thousands of
% lobby
% of Grand Central Station, where many trains arrive every hour at dozens
% of .
% People enter the lobby from the trains, mill around
% a little in the lobby, then queue up to leave the lobby by
% escalators.
% The escalators are close to their capacity.
% Many thousands of people pass through every hour. Now
Burning fossil fuels {{is}} undeniably increasing
the \COO\ concentration in the atmosphere and in the surface
oceans. No climate scientist disputes this fact. When
it comes to \COO\ concentrations, man {\em{is}\/} significant.
OK. Fossil fuel burning increases \COO\ concentrations significantly.
But does it matter? ``Carbon is nature!'', the
\ind{oilspinner}s remind us, ``Carbon is life!''
If \COO\ had no harmful effects, then indeed carbon emissions would not matter. However,
\nlabel{isaGHG}carbon dioxide is a
\ind{greenhouse gas}. Not the strongest greenhouse gas,
but a significant one nonetheless. Put more of it in the \ind{atmosphere}, and it
does what greenhouse gases do: it absorbs \ind{infrared} radiation (heat) heading
out from the \ind{earth} and reemits it in a random direction; the effect of this
random redirection of the atmospheric heat traffic is to
% slightly
impede\index{greenhouse effect}\index{global warming}\index{climate change}
the flow of \ind{heat} from the \ind{planet}, just like a \ind{quilt}.
% duvet
So carbon dioxide has a warming effect.\nlabel{pCWarm}
% impedes heat loss from
This fact is based
not on complex historical records of global temperatures
but on the simple physical properties
of \COO\ molecules. Greenhouse gases are a quilt, and \COO\ is one layer
of the quilt.
So, if humanity succeeds in doubling or tripling \COO\ concentrations (which is
where we are certainly heading, under business as usual), what
happens? Here, there is a lot of uncertainty. Climate science is
difficult. The climate
is a complex, twitchy beast, and
exactly how much warming \COO-doubling would produce is uncertain.
The consensus of the best climate models
seems to be that doubling the \COO\ concentration would have roughly the same effect as
increasing the intensity of the sun by 2\%, and
would bump up the global mean temperature by something like 3\degreesC.
This would be what historians call {{a \ind{Bad Thing}}}.
%% *** Seb says this grates.
I won't recite the whole \ind{litany}\nlabel{plitany}
of probable drastic effects, as I am sure you've heard it before.
% This is a nice short 2-page document:
The litany begins ``the \ind{Greenland icecap}
would gradually melt, and, over a period of a few 100 years,
sea-level\index{sea-level rise} would rise by about 7\,metres.''\index{sea-level rise}
The brunt of the litany falls on future generations.
Such temperatures have not been seen on earth for at least
100\,000 years,\nlabel{pPlioceneEemian}
% 3 million years,\nlabel{pPliocene}
and it's
conceivable that the ecosystem would be so significantly altered that the
earth would stop supplying some of the goods and services that we currently
take for granted.
%% *** MJB did not think this was funny
\vfillone
\pagebreak[4]
Climate modelling\index{climate modelling}
is difficult and is dogged by uncertainties.
% , and I doubt that any of the
% models yet made are accurate enough to give good predictions.
But \ind{uncertainty} about exactly how the
climate will respond to extra greenhouse gases is no justification
for inaction. If you were riding a fast-moving \ind{motorcycle} in \ind{fog}
near a cliff-edge, and you didn't have a good \ind{map} of the
\ind{cliff}, would the lack of a map justify {\em{not}\/} slowing the
bike down?
So, who should slow the bike down?
Who should clean up carbon emissions?
Who is responsible for climate change?
This is an ethical question, of course, not a scientific one, but
ethical discussions must be founded on facts.\index{ethics}
% So let's now explore
% the facts about present and past greenhouse gas emissions.
Let's now explore
the facts about greenhouse gas emissions.
First, a word about the units in which they are measured.
Greenhouse gases include carbon dioxide, methane, and nitrous oxide;
each gas has different physical properties;
it's conventional to express all gas emissions in ``equivalent
amounts of carbon dioxide,'' where ``equivalent'' means ``having the
same warming effect over a period of 100 years.''
One \ton\ of carbon-dioxide-equivalent may be abbreviated
as ``1\,t\,\COOe,'' and one \ind{billion} \tons\
(one thousand million \tons) as ``1\,Gt\,\COOe''
(one gigaton).
In this book $1\,$t means one metric ton (1000\,kg).
% often written as ``tonne.''
I'm not going to distinguish
imperial
% ``short'' and ``long''
tons, because they
% so nearly equal:
% 1 metric tonne = 1000\,kg;
% 1 long ton = 2240\,lb = 1016\,kg.)
differ by less than 10\% from the metric ton or tonne.
%\subsection{Ethics of pollution-reduction and pollution-cleanup}
In the year 2000, the world's greenhouse gas emissions\index{greenhouse gas emissions} were
about 34 billion \tons\ of {\COO-equivalent}\index{carbon dioxide!equivalent} per year.
% }
% \COO\ emissions
An incomprehensible number. But we can render it more
comprehensible and more personal by dividing by the
number of people on the planet, 6 billion, so as to obtain
the greenhouse-gas pollution {\em{per person}}, which is
about
% about 5 or 6
$5\dfrac{1}{2}$\,\tons\ \COOe\ per year per person.
We can thus represent the world emissions by a rectangle
whose width is the population (6 billion) and whose height is
the per-capita emissions.
\medskip\\
%\newpage
%% , which I'll round up to six tons per person.
%\subsection{Where the carbon's coming from}
\begin{wide}
\mbox{\epsfbox{cmetapost/worldCOO.1}}
\end{wide}
\smallskip
\vfillone
\clearpage
%\label{figGHG1}
% Six
% $5\dfrac{1}{2}$\,
% Five and a half
% \tons\ per year per person is equivalent
% to every person burning one and a half tons of coal
% per year.
%
Now, all people are created equal, but
% some are more equal than others.
we don't all emit
% six
$5\dfrac{1}{2}$\,\tons\ of \COO\ per year.
We can break down the emissions of the year 2000, showing
how the 34-billion-ton rectangle is shared between the regions of the world:
\medskip
\medskip
\\
\begin{wide}
\mbox{\epsfbox{cmetapost/regionsCOO.1}}%
\label{figGHG2}
\end{wide}
\medskip
%\caption[a]{
%Breakdown of world greenhouse gas emissions by region.
%}
%
% In this picture I've broken the world down into eight regions. Each rectangle represents
This picture, which is on the same scale as the previous one,
divides the world into eight regions. Each rectangle's area represents
the greenhouse gas emissions of one region.\index{greenhouse gas emissions!by region}\index{data!greenhouse gas emissions!by region}
The width of the rectangle is the population of the region, and the height
is the average per-capita emissions in that region.
% What you might pick up from this picture are the facts that
In the year 2000, Europe's per-capita greenhouse gas emissions were twice the world average;
and North America's were four times the world average.
We can continue subdividing, splitting each of the regions into countries.
% In principle
% we could subdivide the original rectangle into 6 billion rectangles, one for every one
% of us, showing . But I've only got
This is where it gets really interesting:
\vfillone
% \begin{figure}
% \figuredangle{
\begin{wide}
\mbox{\epsfbox{cmetapost/countriesCOO.1}}
\end{wide}
%}{
%\caption[a]{
%Breakdown of world greenhouse gas emissions by country.
%}
%\label{figGHG3}
% }
% \end{figure}
The major countries with the biggest per-capita emissions
are Australia, the USA, and Canada. European countries, Japan, and South Africa are
notable runners up. Among European countries, the United Kingdom is
resolutely average.\index{greenhouse gas emissions!by country}\index{data!greenhouse gas emissions!by country}
What about China, that naughty ``out of control'' country?
Yes, the area of China's rectangle is about the same as the USA's, but
% America's
the fact is that their per-capita emissions are {\em{below}\/}
the world average. India's per-capita emissions are less than {\em{half}\/} the world
average.
Moreover, it's worth bearing in mind that much of the industrial
emissions of China and India are associated with the manufacture
of {\em{\ind{stuff} for rich countries}}.
So, assuming that ``something needs to be done''
% about climate change, assuming that the world needs
to
reduce greenhouse gas emissions, who has a special responsibility to do something?
As I said, that's an ethical question. But I find it hard to imagine
any system of ethics that denies that the responsibility falls especially on
the countries to the left hand side of this diagram -- the countries whose emissions are
two, three, or four times the world average.
Countries that are most able to pay.
Countries like Britain and the USA, for example.
\subsection{Historical responsibility for climate impact}
% There's another factual foundation I'd like to explore.
If we assume that the climate has been damaged by human activity,
and that someone needs to fix it, who should pay? Some people say
``the polluter should pay.''\index{greenhouse gas emissions!historical}\index{data!greenhouse gas emissions!historical}
The preceding pictures showed who's doing the polluting today.
But it isn't the {\em{rate}\/} of \COO\ pollution that matters, it's
the cumulative {\em{total}\/} emissions; much of the emitted
carbon dioxide (about one third of it)
will hang around in the atmosphere for at least 50 or 100 years.
% So if there's damage that needs rectifying, it's not so important
% who are the biggest emitters today;
% we should hold responsible the people with the biggest historical
If we accept the ethical idea that ``the polluter should pay''\index{polluter pays}
\index{ethics!pollution}then we should
ask how big is each country's historical footprint.
The next picture\nlabel{pCAITCOO} shows each country's
% region's
cumulative
emissions of \COO, expressed as an average emission rate over the period 1880--2004. \smallskip
%\begin{figure}
% \figuredangle{
%\begin{wide}
%\mbox{\epsfbox{cmetapost/Cum/regionsCOO.1}}
%\end{wide}
%}{
%\caption[a]{
% Breakdown of world \COO\ emissions by region, averaged over the period 1880--2004.
%}
%\label{figGHG18802}
%5 }
% \end{figure}
% When we drill down to the country level, what do we find?
%\begin{figure}
% \figuredangle{
\begin{wide}
\mbox{\epsfbox{cmetapost/Cum/countriesCOO.1}}
\end{wide}
%}{
%\caption[a]{
%Breakdown of world \COO\ emissions by country, averaged over the period 1880--2004.
%}
%\label{figGHG18803}
% }
% \end{figure}
% Why am I going on about this?
% Because I sometimes meet British people who say ``there's no point
% in Britain doing anything''. But
Congratulations, Britain!\index{data!greenhouse gas emissions}
% As \figref{figGHG18803} shows,
The UK has made it onto the winners' podium. We may be only an
average European country today, but in the table of historical
emitters, per capita, we are second only to the USA.\nlabel{pCongUK}
%% I left out Luxembourg because they are too small to count
%% ABILITY TO PAY
OK, that's enough ethics. What do scientists reckon needs to be done,
to avoid a risk of giving the earth
a 2\degreeC\ temperature rise (2\degreeC\ being the rise above which they predict lots
of bad consequences)?
% over pre-industrial levels?
% In a nutshell, t
The consensus is clear.
We need to get off our fossil fuel habit, and we need to do so fast.
Some countries, including Britain, have committed to
%% ADDED
at least a
%% end ADDED
60\% reduction in
greenhouse-gas emissions by 2050,\nlabel{pB60}
% changed such to 60%
but it must be emphasized that 60\% cuts,
radical though they are, are unlikely to
cut the mustard. If the world's emissions
were gradually reduced by 60\% by 2050,
climate scientists reckon it's more likely
than not that global temperatures will rise
by more than 2\degreeC. The sort of cuts we need to aim for
are shown in \figref{figHighS}.
This figure shows two possibly-safe emissions scenarios
presented by \citet{HighStakes} in a report from the
Institute for Public Policy Research.
%From introduction to \cite{HighStakes}
%``We do not have decades in which to bend the global \COO\
%curve: we have less than ten years.''
%Simon Retallack
%Head of the Climate Change Team, ippr
%
%\begin{figure}\footnotesize
%\figuremargin{
%\begin{center}
%\begin{tabular}{cc}
%\mbox{\epsfxsize=57mm\epsfbox{../data/highstakes.G.eps}}&
\marginfig{
\noindent
\mbox{\epsfxsize=53mm\epsfbox{../data/highstakes.t.eps}} \\
%(a)&(b)\\
%}{
\caption[a]{%
Global emissions for two scenarios\index{greenhouse gas emissions}
considered by \index{Baer, Paul}{Baer} and \index{Mastrandrea, Michael}{Mastrandrea},\label{pBaer}
% not Maer, Baer!
% (a) Fossil fuel emissions expressed in GtC. (b) The same emissions,
expressed in tons of \COO\ per year per person, using a world
population of six billion. Both scenarios are believed to offer a
modest chance of avoiding a 2\degreeC\ temperature rise
above the pre-industrial level. }
\label{figHighS}
}%
%\end{figure}
The lower curve
% (their scenario I5)
assumes that a decline in
emissions started in 2007, with total global emissions falling
at roughly 5\% per year. The upper curve
% (their scenario D4)
assumes a brief delay in the start of
the decline, and a 4\% drop per year in global emissions.
Both scenarios are believed to offer a modest
chance of avoiding a 2\degreeC\ temperature rise
above the pre-industrial level.
In the lower scenario,
the chance that the temperature rise will {\em{exceed}\/} 2\degreeC\ is
estimated to be 9--26\%.
In the upper scenario, the chance of exceeding 2\degreeC\ is
estimated to be 16--43\%.
These possibly-safe emissions trajectories, by the way, involve significantly
sharper reductions in emissions than any of the scenarios
presented by the Intergovernmental Panel on Climate Change (IPCC),
or by the Stern Review (2007)\nocite{SternRev}\nocite{Socolow36}.
% , or by \cite{Socolow36}.
% Baer and Mastrandrea's conclusion:
% global greenhouse gas emissions must be made to fall by roughly 80\%
% by 2050. And under any equitable system for sharing
% this obligation, surely British emissions must fall by
% roughly 90\% by 2050.
These possibly-safe trajectories require global emissions to fall by
70\% or 85\% by 2050.
% These scenarios both call for steady reductions in emissions, so it may be
% misleading to pluck out the target emissions in 2050, as
What would this mean for a country like Britain? If
we subscribe
to the idea of ``\ind{contraction and convergence},'' which means that
all countries aim eventually to have equal per-capita emissions,
then Britain needs to aim for cuts greater than 85\%:
it should get down from its current 11 \tons\ of \COOe\
per year per person to roughly
\begin{figure}[bhtp]
\figuremargin{
\mbox{\epsfbox{../../data/GHG/ghg.1}}
}{
\caption[a]{{\Black{Breakdown of world greenhouse-gas emissions (2000)
by cause and by gas.\index{data!emissions} ``Energy'' includes
power stations, industrial processes, transport, fossil fuel
processing, and energy-use in buildings.
``Land use, biomass burning'' means changes in
land use, deforestation, and the burning of un-renewed biomass such as peat.
``Waste'' includes waste disposal and treatment.
The sizes indicate the 100-year global warming potential
of each source.
Source:
Emission Database for Global Atmospheric Research.
}}}\label{fig.GHG}
}
\end{figure}%
{\Red{1 \ton\ per year per person}} by 2050.
This is such a deep cut, I suggest the best way to think about it is
{\em{no more fossil fuels}}.
One last thing about the climate-change motivation:
while a range of human activities cause
greenhouse-gas emissions, the biggest cause by far is {\bf energy use}.
Some people justify not doing anything
about their energy use by excuses such as ``methane from burping cows causes
more warming than jet travel.'' Yes, agricultural by-products
contributed one eighth of greenhouse-gas emissions in the year 2000.
But energy-use contributed three quarters (\figref{fig.GHG}).
The climate change problem is principally an energy problem.
\section{Warnings to the reader}
OK, enough about climate change.\label{rejoinHere}
I'm going to assume we are motivated to get off fossil fuels.
Whatever your motivation,
the aim of this book is to help you figure out the numbers
and do the arithmetic so that you can evaluate policies; and to lay
a factual foundation so that you can see {\em{which proposals
add up}}.
I'm not claiming that the arithmetic and numbers in
this book are new; the books I've mentioned
by Goodstein, Lomborg, and Lovelock,
for example, are full of interesting numbers and
back-of-envelope calculations, and there are many other helpful
sources on the internet too (see the notes at
the end of each chapter).\label{pageRecom}
%\medskip
What I'm aiming to do in this book is to
% find a way to
make these numbers simple and memorable; to show you how you
can figure out the numbers for yourself;
and to make the situation
%% need for change
so
%% blindingly
clear that any thinking reader will
be able to draw striking
% figure out the
conclusions. I don't want to
feed you my own conclusions.
% My experience as a teacher has taught me this:
Convictions are stronger
% more strong and robust
if they are self-generated, rather than taught.
% by an%% omniscient authority-figure.
Understanding is a creative process.
When you've read this book I hope you'll have
reinforced the confidence
% knowledge
that you can figure anything out.
%\medskip% BREATH
% recently removed section heading
%\section*{Inaccuracy as an aid to understanding}
I'd like to emphasize that the calculations we will do are
%% consciously and
deliberately\index{imprecision, deliberate}
imprecise.\index{inaccuracy, deliberate}\index{deliberate inaccuracy}
Simplification is a key to \ind{understanding}.\index{simplification}
First, by rounding the numbers, we can make them easier
to remember.
Second, rounded numbers allow quick calculations.
For example, in this book, the population of the
United Kingdom
% U.K.\ is
is 60 million, and the population of the world is 6 billion.
% (One \ind{billion} is a thousand million.)
I'm perfectly capable of looking up more accurate figures, but
accuracy would get in the way of fluent thought. For example,
if we learn that
the world's greenhouse gas emissions in 2000
% fossil fuel emissions are currently
were 34\,billion \tonnes\ of \COO-equivalent
per year,
then we can instantly
note, without a calculator, that
the average emissions per person are
5 or 6
% $\dfrac{2}{3}$
\tonnes\ of \COO-equivalent per person per year.
This rough answer
% (34 divided by 6 is 5$\dfrac{1}{2}$)
% is not exact, but it's quick and it's good enough
is not exact, but it's accurate enough to inform interesting
conversations.\index{flight!emissions}\index{travel!emissions}
For instance, if you learn
that a\index{emissions!flight}\index{emissions!travel}
round-trip intercontinental flight\index{intercontinental flight!emissions}%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/cartoon/LowEMan.jpg.eps}}}\\
\end{tabular} \\
{\em{``Look -- it's Low Carbon Emission Man''}}
\end{center}
\caption[a]{
Reproduced by kind permission of PRIVATE EYE /
% Private Eye 1176. 19 January 2007.
Peter Dredge \url{www.private-eye.co.uk}.
}
}
% in a 747
emits nearly two \tonnes\ of \COO\ per passenger,\index{emissions!flying}\index{flight!emissions}\index{jet travel!emissions}
%% 1.83 tonnes for LHR to ZAMBIA, ``cost 11.91''
then knowing the average emissions
yardstick (5-and-a-bit \tonnes\ per year per person)
helps you realize that just one
such plane-trip per year corresponds to over a third
of the average person's carbon emissions.
% Similarly knowing that the population of the United Kingdom is one
% hundredth of the world, we can deduce what level of emissions
% would be fair for the U.K., either dividing :
% (By the way, I'm not going to distinguish
% between ``tonnes'' and ``tons,'' because they
%% so nearly equal:
%% 1 metric tonne = 1000\,kg;
%% 1 long ton = 2240\,lb = 1016\,kg.)
% differ by less than 10\%.)
% for the purposes of this book
% they can be considered equal.)
%
% We're getting ahead of ourselves. We'll come back to carbon pollution
% in chapter \ref{ch.coo}.
Because I round all the numbers when I write them down, sometimes
intermediate (rounded) numbers in a calculation don't exactly
match the final answer or total; the final answer (obtained without any
intermediate rounding) is more accurate.
These minor numerical disagreements don't affect any of the arguments in this book.
% Wherever possible
I like to base my calculations on
everyday knowledge rather than on trawling through impersonal
national statistics. For example, if I want to estimate the typical
wind speeds in Cambridge, I ask
``is my cycling speed usually faster than the wind?''
The answer is yes. So I can deduce that the wind speed in Cambridge
is only rarely faster than my typical cycling speed of
20\,km/h.
% (5.6\,m/s, or 12\,miles per hour).
% 12.4\,miles per hour).
I back up these everyday estimates with other peoples'
calculations and with official statistics. (Please
look for these in each chapter's end-notes.)
This book isn't intended to be a definitive store of
super-accurate numbers. Rather, it's intended to illustrate
how to use approximate numbers as a part of constructive
consensual conversations.
% aimed at consensual
% The goal is to replace confrontation and innumeracy by consensus
% founded on reality.
In the calculations, I'll mainly use the \ind{United Kingdom}
%% or England, or
and occasionally Europe, America, or the whole \ind{world}, but
you should find it easy to redo the calculations for
whatever country or region you are interested in.\index{countries}
% \medskip% BREATH
Let me close this chapter
% preface
with a few more warnings to the reader.
Not only will we make a habit of approximating the numbers
we calculate; we'll also neglect all sorts of details that investors,
managers, and economists have to attend to, poor folks.
If you're trying to launch a renewable technology,
just a 5\% increase in costs may make all the difference between
success and failure, so in business every detail must be tracked.
But 5\% is too
small for this book's radar.
This is a book about factors of 2 and factors of 10. It's about
physical limits to sustainable energy, not current
economic feasibility.
% Business decisions care about undercutting rivals by 5\%.
While economics is always changing, the fundamental limits won't
ever go away. We need to understand these limits.
% recently removed section heading
% www.defra.gov.uk/environment/climatechange/internat/pdf/avoid-dangercc.pdf
% www.defra.gov.uk/environment/climatechange/internat/pdf/avoid-dangercc-execsumm.pdf
% \section{Facts and ethics}
Debates about energy policy are often confusing and
emotional because people mix together
% factual and ethical assertions.
% A final note before we start: discussions about energy policy
% involve two sorts of claims:
{\em{factual}\/} assertions
and {\em{ethical}\/} {{assertions}}.\label{pageEthics}
Examples of {\bf\ind{factual assertions}} are
%% ``1\% of all deaths in America are caused by cars''; and
``global fossil-fuel burning emits
% emissions of \COO\ are
% 7 billion tons of carbon per year'';
34 billion tons of carbon dioxide equivalent per year;''
and ``if \COO\ concentrations are doubled
then average temperatures will increase by 1.5--5.8{\degrees}C
in the next 100 years;''
%% source - page 80 of Dessler and Parson
% above the 1990 level
% increased to 550\,ppm and were held constant'
and ``a temperature rise of 2{\degrees}C would cause
the Greenland ice cap to melt within 500 years;''
and ``the complete melting of the Greenland ice cap would
cause a 7-metre \ind{sea-level rise}.''
% Factual assertions are scientific assertions.
A factual assertion is either true or false; figuring out {\em{which}\/}
% it really is
may be difficult; it is a scientific question.
For example, the assertions I just gave
are either true or false. But we don't know whether they
are all true. Some of them are currently judged ``very likely.''
The difficulty of deciding which factual assertions are true leads to
debates in the scientific community. But given
sufficient scientific experiment and discussion,
the truth or falsity of most factual assertions can
eventually be resolved, at least ``beyond reasonable doubt.''
% As science progresses
Examples of {\bf\ind{ethical assertions}} are
``it's wrong to exploit global resources in a way that
imposes significant costs on future generations;'' and
``polluting should not be free;'' and
``we should take steps to ensure that it's unlikely that
\COO\ concentrations will double;'' and ``politicians
should agree a cap on \COO\ emissions;'' and ``countries
with the biggest \COO\ emissions over the last century have a duty
to lead action on climate change;''
% lead the way to a low-carbon future'';
and ``it is fair to share
\COO\ emission rights equally across the world's population.''
Such assertions are not ``either true or false.''
Whether we agree with them depends on our ethical judgment, on our values.
Ethical assertions may be incompatible with each other; for example,
Tony Blair's
% `New Labour'
government declared a radical policy on \COO\ emissions:
``the United Kingdom should reduce its \COO\ emissions by 60\% by 2050;''
% , and perhaps by 80\%'';
at the same time Gordon Brown, while Chancellor in
that government,
repeatedly urged oil-producing countries
to {\em{increase}\/} oil production.\label{pageGordon}
% p13 Tory document says 80% over the next 50 yrs (2057)
This book is emphatically intended to be about facts, not ethics.
I want the facts to be clear, so that people can have a meaningful
debate about ethical decisions.
I want everyone to understand how the facts constrain the options that are
open to us.
Like a good scientist,
I'll try to keep my views on ethical questions out of the way, though occasionally
I'll blurt something out -- please forgive me.
\marginfig{
\begin{center}
\begin{tabular}{p{50mm}}
%\mbox{\epsfxsize=50mm\epsfbox{../../images/DoNothing4.eps}} \\
\mbox{\epsfxsize=50mm\epsfbox{../../images/DoNothing5.eps}} \\
{\em{``Okay -- it's agreed; we announce -- `to do nothing is not an option!' then
we wait and see how things pan out\ldots''}} \\
\end{tabular}
\end{center}
\caption[a]{
Reproduced by kind permission of PRIVATE EYE /
% Lowe cartoon from Private Eye.
% No.\ 1156, 14 April 2006.
Paul Lowe \url{www.private-eye.co.uk}.
}
}
Whether it's {\em{fair}\/} for Europe and North America to hog the energy cake
is an ethical question;
% Mixed metaphors. Cake image used twice in slightly different meanings. (F. Stajano)
I'm here to remind you of the {\em{fact}\/}
that we can't have our cake and eat it too;
to help you weed out the pointless and ineffective policy proposals;
and to help you identify energy policies that are compatible with your personal values.
% and that will make a difference.
% For example, when people are
% debating whether we should expand wind power or nuclear power or both,
We need a plan that adds up!
\beginfullpagewidth
\small
\section*{Notes and further reading}
At the end of each chapter I note details of ideas
in that chapter, sources of data and quotes,
and pointers to further information.
\ENDfullpagewidth
%\beforenotelist
\small
\begin{widenotelist}
\item[page no.]
\item[\npageref{pageANYQ}]
{\nqs{``\ldots no
other possible way of doing that except through renewables''}};
{\nqs{``anybody who is relying upon
renewables to fill the [energy] gap is living in an utter dream
world and is, in my view, an enemy of the people.''}}
The quotes are from
{\em{Any Questions?}}, 27 January 2006,
BBC Radio 4
\tinyurl{ydoobr}{http://www.bbc.co.uk/radio4/news/anyquestions_transcripts_20060127.shtml}.
{\nqs{Michael Meacher}} was \UK\ environment minister
from 1997 till 2003.
{\nqs{Sir Bernard Ingham}}
was an aide to Margaret Thatcher
when she was prime minister, and
was Head of the Government Information Service. He is
secretary of Supporters of Nuclear Energy.
% {http://www.bbc.co.uk/radio4/news/anyquestions_transcripts_20060127.shtml}
% \durl{{http://www.bbc.co.uk/radio4/news/anyquestions\_transcripts\_20060127.shtml}}
% http://www.bbc.co.uk/radio4/news/anyquestions_transcripts_20060127.shtml
% http://tinyurl.com/ydoobr
%\medskip
\item[\npageref{pagePorritt}] {\nqs{Jonathon Porritt}} (March 2006).
{\em Is nuclear the answer?} Section 3. Advice to Ministers.
\myurlb{www.sd-commission.org.uk}{http://www.sd-commission.org.uk/}
%\medskip
%\item[\npageref{pageLovelock}]
% {\nqs{James Lovelock}}. {\myurl{http://www.ecolo.org/lovelock/}}\nocite{Lovelock2006}
%\medskip
\item[\npageref{AnnLeslie}]
{\nqs{``Nuclear is a money pit''}},
{\nqs{``We have a {\em{huge}\/} amount of wave and wind.''}}
Ann Leslie, journalist.
Speaking on {\em{Any Questions?}}, Radio 4, 10 February 2006.
\item[\npageref{pageLA}]
{\nqs{Los Angeles residents drive \ldots\ from Earth to Mars}} --
\cite[page 34]{FiftyThings}.
% from page 34 of ``50 Simple things you can do to save the earth''.
% {The Earth works Group} (1989), published by {The Earthworks Press},
% {Berkeley, California},
% ISBN: {0-929634-06-3}.
% %\medskip
\item[\npageref{ptarget}]
{\nqs{\url{targetneutral.com}}}
charges just \pounds4 per ton of \COO\ for their ``neutralization.''
(A significantly lower price than any other
``offsetting'' company I have come across.)
At this price, a typical Brit could have his 11 tons
per year ``neutralized'' for just \pounds44 per year!
Evidence that BP's ``neutralization'' schemes don't really add up
comes from the fact that its projects have not achieved the Gold Standard
\myurlb{www.cdmgoldstandard.org}{http://www.cdmgoldstandard.org/} (Michael Schlup, personal communication).
Many ``carbon offset'' projects have been exposed as worthless
by
% award-winning journalist Fiona Harvey
Fiona Harvey of the Financial Times
\tinyurl{2jhve6}{http://www.ft.com/cms/s/0/48e334ce-f355-11db-9845-000b5df10621.html}.
% , work for which she was named environmental journalist of the year.
% http://www.guardian.co.uk/environment/2007/nov/08/pressandpublishing
\item[\npageref{windNuke4}]
{\nqs{
People who want to promote renewables
over nuclear,\index{nuclear power} for example, say ``offshore wind power
could power all UK homes.''}}
%
At the end of 2007, the UK government
announced that they would allow the building of
offshore wind turbines ``enough to power all UK homes.''
Friends of the Earth's renewable energy campaigner,
Nick Rau, said the group welcomed the government's announcement.
%
``The potential power that could be generated by this industry is enormous," he said.
\tinyurl{25e59w}{http://news.bbc.co.uk/1/low/uk_politics/7135299.stm}.
From the Guardian
\tinyurl{5o7mxk}{http://www.guardian.co.uk/environment/2007/dec/10/politics}:
\index{Sauven, John}John Sauven,
the executive director of \ind{Greenpeace},
said that the plans amounted to a ``wind energy revolution."
``And \ind{Labour} needs to drop its obsession with \ind{nuclear power},
which could only ever reduce emissions by about 4\% at some time in the distant future."
\index{Friends of the Earth}%
%'s renewable energy campaigner,
Nick Rau\index{Rau, Nick}
said: ``We are delighted the government is getting serious about the potential for offshore wind, which could generate 25\% of the UK's electricity by 2020.''
A few weeks later, the government
announced that it would permit new nuclear stations to be built.
``Today's decision to give the go-ahead to a new generation of nuclear power stations \ldots\ will do little to tackle climate change,'' Friends of the Earth warned \tinyurl{5c4olc}{http://www.foe.co.uk/resource/press_releases/green_solutions_undermined_10012008.html}.
In fact, the two proposed expansions -- of offshore wind and
of nuclear -- would both deliver just the same amount
of electricity per year.
The total permitted offshore wind power of 33\,GW would on average
deliver 10\,GW, which is 4\,kWh per day per person;
and the replacement of all the retiring nuclear power stations
would deliver
10\,GW, which is 4\,kWh per day per person.
Yet in the same breath, anti-nuclear campaigners say that the
nuclear option would ``do little,'' while the wind option
would ``power all UK homes.''
% 21.1 million homes , 13 kWh/d per home, that's
The fact is, ``powering all UK homes'' and
``only reducing emissions by about 4\%'' are the same thing.
% Germany has 22 GW.
% Both would deliver 10\,GW on average.
\item[\npageref{pageWaterCar}]
{\nqs{``water-powered car''}}\label{pnWaterCar}
{\em New Scientist}, 29th July 2006, p.\,35.
This article, headlined ``Water-powered car might be available by 2009,'' opened thus:
``Forget cars fuelled by alcohol and vegetable oil. Before long, you
might be able to run your car with nothing more than water in its
fuel tank. It would be the ultimate zero-emissions vehicle.
``While water is not at first sight an obvious power source, it has a
key virtue: it is an abundant source of hydrogen, the element widely
touted as the green fuel of the future.''
%% http://environment.newscientist.com/channel/earth/energy-fuels/mg19125621.200-a-fuel-tank-full-of-water.html
The work {\tem{New Scientist}\/} was describing was not ridiculous --
it was actually about a car using {\em\ind{boron}\/}
as a fuel, with a boron/water reaction
as one of the first chemical steps.
Why did {\tem\ind{New Scientist}} feel the urge to turn this into
a story suggesting that water was the fuel? Water is not a fuel.
It never has been, and it never will be. It is already burned!
The first law of thermodynamics says you can't get energy for nothing;
you can only convert energy from one form to another.
% The second law of thermodynamics says,
The energy in any engine must come from somewhere.
%
Fox News peddled an even more absurd story
\tinyurl{2fztd3}{http://www.jalopnik.com/cars/
alternative-energy/
now-thats-some-high-quality-
h20-car-runs-on-water-177788.php}.
%http://tinyurl.com/2fztd3
%% alternate link to the video:
%% http://www.freeenergynews.com/Directory/BrownsGas/WaterFuel.wmv
\item[\npageref{pageDK}]
{\nqs{Climate change is a far greater threat to the world than
international terrorism}}.
Sir David King,
Chief Scientific Advisor to the \UK\ government,
% Friday 9th
January, 2004.
\tinyurl{26e8z}{http://news.bbc.co.uk/1/hi/sci/tech/3381425.stm}
%\durl{{http://news.bbc.co.uk/1/hi/sci/tech/3381425.stm}}
% http://tinyurl.com/26e8z
%\medskip
\item[\npageref{pageglory}] {\nqs{the glorification of travel}} -- an allusion to
the offence of ``glorification'' defined in the UK's Terrorism Act which came into force
on 13 April, 2006.
%% http://tinyurl.com/ykhayj
\tinyurl{ykhayj}{http://politics.guardian.co.uk/terrorism/story/0,,1752937,00.html}
%\durlp{{http://politics.guardian.co.uk/terrorism/story/0,,1752937,00.html}}
%\medskip
\item[\npageref{fig.NorthSO}]
{\nqs{Figure \ref{fig.NorthSO}}}.
This figure shows
production of \ind{crude oil} including lease condensate, natural gas plant
liquids, and other liquids,
and refinery processing gain.
Sources: EIA, and BP statistical review of world energy.
\item[\npageref{pHero}]
{\nqs{The first practical steam engine was invented in \ind{1698}}}.
In fact, Hero of Alexandria described a steam engine, but
given that Hero's engine didn't catch on in the following 1600 years,
I deem Savery's 1698 invention
the first {\em practical\/} steam engine.
% Aeolipile
\item[\npageref{fig.co2graph0}]% {figKeeling}]
{\nqs{\Figsref{fig.co2graph0} and \ref{figKeeling}:
Graph of \ind{carbon dioxide} concentration}}.
The data are collated from
\citet{Keeling2005} (measurements spanning 1958--2004);
% http://cdiac.ornl.gov/trends/co2/sio-mlo.htm
% C.D. Keeling and T. P. Whorf for records back to the late 1950s.
\citet{Neftel1994} (1734--1983);
% A. Neftel et al.;
% http://cdiac.ornl.gov/trends/co2/siple.htm
% 1734-1983
\citet{Etheridge1998} (1000--1978);
% D.M. Etheridge et al.;
%% http://cdiac.ornl.gov/trends/co2/lawdome.html
%% 1006 A.D.-1978 A.D.
%% Not J.M. Barnola et al.
%% 417,160 - 2,342 years BP
\citet{Siegenthaler2005} (950--1888\,AD); and
% Siegenthaler et al
% from 956AD to 1737AD and 958 to 1888
\citet{Indermuhle1999} (from 11\,000 to 450 years before present).%
\index{Keeling, C. D.}\index{Whorf, T. P.}\index{Neftel, A.}%
\index{Etheridge, D. M.}\index{Siegenthaler, Urs}\index{Indermuhle, A.}
This graph, by the way, should not be confused with
the ``hockey stick graph'', which
\index{hockey stick graph}shows
the history of global {\em{temperatures}}.
Attentive readers will have noticed that the climate-change
argument I presented
makes no mention of {\em{historical}\/} temperatures.
% , which don't have
% such a clear upward kink (yet).
{\nqs{\Figsref{fig.England5a}--\ref{figKeeling}:}}
% http://www.nber.org/databases/macrohistory/contents/chapter01.html
{\nqs{Coal production}} numbers are from
\citet{Jevons},
\cite{Malanima06},
\cite{hyde06},
\cite{NBER},
\citet{HatcherCoal},
\citet{FlinnV2},
\citet{ChurchV3},
\citet{SuppleV4},
\citet{AshworthV5}.
% http://www.mnp.nl/hyde/prod_data/coal/
Jevons was the first ``Peak Oil'' author.\index{peak oil}\index{Jevons, William Stanley}
In 1865, he estimated Britain's easily-accessible coal reserves,
looked at the history of exponential growth in consumption,
and predicted the end of the exponential growth
and the end of the British dominance of world industry.
``We cannot long maintain our present rate of increase of consumption. \ldots
the check to our progress must become perceptible within a century from the
present time. \ldots
the conclusion is inevitable,
that our present happy progressive condition is a thing of limited duration.''
Jevons was right. Within a century British coal production indeed peaked,
and there were two world wars.
%% the more rapid and continued our present expansion, the shorter must be its continuance.
\end{widenotelist}
%\ENDfullpagewidth
\small
\begin{notelist}
\item[\npageref{pSceptic}]
{\nqs{{Dominic Lawson}\index{Lawson, Dominic},
a columnist from the {\ind{Independent}}}}.
My quote is adapted from Dominic Lawson's
column in the {\em{Independent}},
% Friday
8 June, 2007.%
\amarginfignocaption{t}{
\begin{center}
\mbox{\epsfbox{metapost/sign.44}}
\end{center}
%\caption[a]
{
The weights of an atom of carbon and a molecule of \COO\
are in the ratio 12 to 44, because the carbon atom
weighs 12 units and the two oxygen atoms weigh 16 each.
$12+16+16 = 44$.
}
}
It is not a verbatim quote: I edited his words to make them briefer but
took care not to correct any of his errors.
% pungent
{\nqs{All three numbers he mentions are incorrect}}.
Here's how he screwed up.
First, he says ``carbon dioxide'' but gives numbers
for carbon: the
burning of fossil fuels sends {\em 26\/} gigatonnes of \COO\ per year into the
atmosphere (not 7 gigatonnes). A common mistake.
Second, he claims that the oceans send 36\,000 gigatonnes
of carbon per year into the atmosphere. This is a far worse
error: 36\,000 gigatonnes
is the {\em total amount\/} of carbon in the ocean! The
annual {\em{flow}\/} is much smaller -- about 90 gigatonnes of carbon
per year (330\,\GtCOO/y), according to
standard diagrams of the carbon cycle
% 120 land; 90 ocean
\tinyurl{l6y5g}{http://www.grida.no/climate/ipcc_tar/wg1/fig3-1.htm}
(I believe this 90\,\GtC/y
is the estimated flow rate, were the
atmosphere suddenly
to have
its \COO\ concentration reduced to zero.)
Similarly his ``1900 gigatonne'' flow from biosphere to atmosphere
is wrong. The correct figure according to the standard
diagrams is about 120 gigatonnes
of carbon per year (440\,\GtCOO/y).
\end{notelist}
%\beginfullpagewidth
\small
\begin{widenotelist}
\item[]
Incidentally, the observed rise in \COO\ concentration is nicely in line with what you'd
expect, assuming most of the human emissions of carbon remained in the atmosphere.
From 1715 to 2004, roughly
% 315 billion tons of carbon
1160\,Gt\,\COO\
have been released to the atmosphere from the consumption of fossil fuels and cement production
\citep{MarlandBA}. If {\em{all}\/} of this \COO\ had stayed in the atmosphere, the concentration
would have risen by 160\,ppm (from 280 to 440\,ppm). The actual rise has been about
100\,ppm
(from 275 to 377\,ppm). So roughly 60\% of what was emitted is now in the atmosphere.
% I calculated this in AllEmissions
\item[\npageref{pCWarm}]
{\nqs{Carbon dioxide has a warming effect}}.\index{carbon dioxide}
The over-emotional debate about this topic is getting quite tiresome,
isn't it? ``The science is now settled.'' ``No it isn't!'' ``Yes it is!''
I think the most helpful thing I can do here is direct anyone who wants
a break from the shouting to a brief report
written by \citet{NAP79}. This report's
% NAS
conclusions carry weight
because the \ind{National Academy of Sciences} (the US equivalent of the
Royal Society)
commissioned the report and selected its authors on the basis of their
expertise, ``and with regard for appropriate balance.''
The study group
% In response to a request from the Director of the Office of Science and
%Technology Policy, the President of the National Academy of Sciences
was convened
%a study group
``under the auspices of the Climate Research Board
of the National Research Council to assess the scientific basis for projection
of possible future climatic changes resulting from man-made releases of
carbon dioxide into the atmosphere.''
Specifically, they were asked:
``to identify the principal premises on which our current understanding
of the question is based,
to assess quantitatively the adequacy and uncertainty of our knowledge
of these factors and processes, and
to summarize in concise and objective terms our best present
understanding of the carbon dioxide/climate issue for the benefit of policy-makers.''
The report is just 33 pages long, it is free to download
\tinyurl{5qfkaw}{http://www.nap.edu/catalog.php?record_id=12181},
and I recommend it.
It makes clear which bits of the science were already settled in \ind{1979},
and which bits still had uncertainty.
Here are the main points I picked up from this report.
First, doubling the atmospheric \COO\ concentration
would change the net heating of the troposphere, oceans, and land by
an average power per unit area of roughly 4\,\Wmm,\nlabel{pKeyGW}
if all other properties of the atmosphere remained unchanged.
This heating effect can be compared with the average power absorbed
by the atmosphere, land, and oceans, which is 238\,\Wmm.
So doubling \COO\ concentrations
would have a warming effect equivalent to increasing the
intensity of the sun by $4/238 = 1.7$\%.
%% world power consumption is 15TW 510,065,600 km**2
%% 15TW/( 510,065,600 km**2 ) in W/square meter = 0.03 Wmm
%% That's very similar to natural geothermal!! 0.06 W/mm
Second, the consequences of this \COO-induced heating are hard to predict,
on account of the complexity of the atmosphere/ocean system,
but the authors predicted a global surface warming of between 2\degreesC\ and
3.5\degreesC,
with greater increases at high latitudes.
Finally, the authors summarize: ``we have tried but have been unable to find any overlooked
or underestimated physical effects that could reduce the currently estimated
global warmings due to a doubling of atmospheric \COO\ to negligible
proportions or reverse them altogether.''
They warn that, thanks to
the ocean, ``the great and ponderous flywheel of the global climate system,''
it is quite possible that the warming would occur sufficiently
sluggishly that it would be difficult to detect in the coming decades. Nevertheless
``warming will eventually occur, and the associated regional climatic changes
\ldots\ may well be
significant.''
The foreword by the chairman of the Climate Research Board,
Verner E. Suomi, summarizes the conclusions
% of ``this brief but intense investigation''
with a famous cascade of double negatives. ``If carbon dioxide continues to
increase, the study group finds no reason to doubt that climate changes will
result and no reason to believe that these changes will be negligible.''
% Refer to Hansen too. ***
\item[\npageref{plitany}]
{\nqs{The \ind{litany} of probable drastic effects of climate change --
I'm sure you've heard it before.}}
See
\tinyurl{2z2xg7}{http://assets.panda.org/downloads/2_vs_3_degree_impacts_1oct06_1.pdf}
if not.
\item[\npageref{figGHG2}]
{\nqs{Breakdown of world greenhouse gas emissions by region and by country}}.
Data source: Climate Analysis Indicators Tool (CAIT)
Version 4.0. (Washington, DC: World Resources Institute, 2007).
The first three figures show national totals of all six major greenhouse gases
(\COO, CH$_4$, N$_2$O, PFC, HFC, SF$_6$), excluding
contributions from
land-use change and forestry.
The figure on \pref{pCAITCOO} shows cumulative emissions of \COO\ only.
\item[\npageref{pCongUK}]
{\nqs{Congratulations, Britain!
\ldots in the table of historical
emissions, per capita, we are second only to the USA}}.
Sincere apologies here to \ind{Luxembourg}, whose historical per-capita
emissions actually exceed those of \ind{America} and \ind{Britain};
but I felt the winners' podium
should really be reserved for countries having both large per-capita and
large total emissions.
%% see sustainable/refs/carbon/Cum/europe
In total terms the biggest historical emitters are,
in order, USA (322\,\GtCOO), Russian Federation\index{Russia} (90\,\GtCOO),
\ind{China} (89\,\GtCOO), \ind{Germany} (78\,\GtCOO), \ind{UK}
(62\,\GtCOO), \ind{Japan} (43\,\GtCOO),
\ind{France} (30\,\GtCOO),
\ind{India} (25\,\GtCOO), and \ind{Canada} (24\,\GtCOO).
% ukraine poland italy next
The per-capita order is: Luxembourg, USA, United Kingdom,
\ind{Czech Republic},
\ind{Belgium},
\ind{Germany}, %6
\ind{Estonia}, %7
\ind{Qatar}, %8
and Canada.
%%% ADDED
\item[\npageref{pB60}]
{\nqs{Some countries, including
Britain, have committed to at least a 60\% reduction in
greenhouse-gas emissions by 2050}}.
Indeed, as I write, Britain's commitment is
being increased to an 80\% reduction relative to 1990 levels.
% Gordon Brown
% http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/09/23/eaco2123.xml
% CCC
% http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/10/06/eaemissions106.xml
\item[\npageref{pBaer}]
{\nqs{\Figref{figHighS}}}.
In the lower scenario, the chance that the temperature rise will exceed
2\degreeC\ is estimated to be 9--26\%; the cumulative carbon
emissions from 2007 onwards are 309\,\GtC; \COO\ concentrations reach
a peak of 410\,ppm, \COOe\ concentrations peak at 421\,ppm, and in
2100 \COO\ concentrations fall back to 355\,ppm. In the upper
scenario, the chance of exceeding 2\degreeC\ is estimated to be
16--43\%; the cumulative carbon emissions from 2007 onwards are
415\,\GtC; \COO\ concentrations reach a peak of 425\,ppm, \COOe\
concentrations peak at 435\,ppm, and in 2100 \COO\ concentrations
fall back to 380\,ppm.
%
% Figure 7-3 of Climate Change 2001 Synthesis report
% says that from 2001 to 2100, 714 GtC could be emitted
% and stabilize at 450 ppmv. Cost of doing this would
% be between 4 and 18 trillion 1990$.
%
See also \myurlb{hdr.undp.org/en/reports/global/hdr2007-2008/}{http://hdr.undp.org/en/reports/global/hdr2007-2008/}.
\item[\npageref{pageRecom}]
{\nqs{there are many other helpful
sources on the \ind{internet}}.}
I recommend, for example:
% \par
BP's {\em{Statistical Review of World Energy}\/}
\tinyurl{yyxq2m}{http://www.bp.com/genericsection.do?categoryId=93&contentId=2014442},
%\durlp{http://www.bp.com/genericsection.do?categoryId=93\&contentId=2014442}%,
the Sustainable Development Commission
\myurlb{www.sd-commission.org.uk}{http://www.sd-commission.org.uk/},
the Danish Wind Industry Association
\myurlb{www.windpower.org}{http://www.windpower.org/en/core.htm},
Environmentalists For Nuclear Energy
\myurlb{www.ecolo.org}{http://www.ecolo.org/},
Wind Energy Department, Ris{\o} University
\myurlb{www.risoe.dk/vea}{http://www.risoe.dk/vea/},
DEFRA\
\myurlb{www.defra.gov.uk/environment/statistics}{http://www.defra.gov.uk/environment/statistics/},
especially the book
{\em Avoiding Dangerous Climate Change\/}
\tinyurl{dzcqq}{http://www.defra.gov.uk/environment/climatechange/internat/pdf/avoid-dangercc.pdf},
the Pembina Institute \myurlb{www.pembina.org/publications.asp}{http://www.pembina.org/publications.asp},
and the DTI (now known as BERR)\ \myurlb{www.dti.gov.uk/publications/}{http://www.dti.gov.uk/publications/}.
%\medskip
\item[\npageref{pageEthics}]
{\nqs{{{factual}} assertions
and {{ethical}} {{assertions}}}\ldots }
Ethical assertions are also known as ``normative claims'' or ``value judgments,''
and factual assertions
are known as ``positive claims.''
Ethical assertions usually contain verbs like
``should'' and ``must,'' or adjectives like ``fair,'' ``right,'' and ``wrong.''
For helpful further reading
see \citet{DesslerParson}.
\item[\npageref{pageGordon}]
{\nqs{Gordon Brown}.}
% Saturday
On 10th September, 2005,
Gordon Brown\index{Brown, Gordon} said the high price of fuel
posed a significant risk to the European economy and to global growth,
and urged OPEC to raise oil production. Again, six months later, he said
``we need \ldots more production, more drilling, more investment,
more petrochemical investment'' (22nd April, 2006)
\tinyurl{y98ys5}{http://news.bbc.co.uk/1/hi/business/4933190.stm}.
%
Let me temper this criticism of Gordon Brown by
praising one of his more recent initiatives, namely the
promotion of electric vehicles and plug-in hybrids.
As you'll see later, one of this book's conclusions is that
electrification of most transport is a good part of a plan
for getting off fossil fuels.
%\item[\npageref{pPliocene}]
% {\nqs{
% Such temperatures have not been seen on earth for 3 million years.}}
% From \cite{SternRev}:
%``Near the middle of this range of warming (around 2--3\degreeC above today),
%the Earth would reach a
%temperature not seen since the middle Pliocene around 3 million years ago. This level of warming on a
%global scale is far outside the experience of human civilisation.''
% Tertiary was warmer than now. 65 to 2.6 My ago
% Quaternary period == ice ages == 2.6My ago to the present.
% Holocene = last 9000 years == human civilization
\end{widenotelist}
%\ENDfullpagewidth
\normalsize
\bset\chapter{\bcol{The balance sheet}}%{Introduction}
\label{ch.balance}
%\chapter{The Balance Sheet}%{Introduction}
% The balance sheet
%\begin{quote}
\myquote{Nature cannot be fooled.}
{Richard Feynman}
% spelling checked \/
% \end{quote}
%\section{The Balance Sheet}
% The first part of this book is
Let's talk about energy consumption and energy production.
At the moment, most of the energy the developed world
consumes is produced from fossil fuels; that's not sustainable.
Exactly how long we could keep living on fossil fuels
is an interesting question, but it's not the question we'll
address in this book.
I want to think about {\em living without fossil fuels}.
We're going to make two stacks.
\marginfignocaption{\small
\begin{center}
{\mbox{\epsfbox{metapost/stacks.231}}} \\
\makebox[1cm][r]{\sc consumption$\:\:$}\makebox[1cm][l]{$\:\:$\sc production} \\
\end{center}
}%
In the left-hand, red stack we will add up our energy consumption,
and in the right-hand, green stack, we'll add up sustainable energy production.
We'll assemble the two stacks gradually, adding items one at a time
as we discuss them.
% Chapters with red headings deal with
% consumption, and chapters with green headings deal with
% sustainable production.
% I'm going to assume that we're interested
% in life without fossil fuels.
The question addressed in this book is ``can we {\em{conceivably}\/}
live sustainably?'' So, we will add up all {\em{conceivable}\/}
sustainable energy sources and put them in the right-hand, green stack.
%
% \medskip% BREATH
% recently removed section heading
%\section{The consumption column}
In the left-hand, red
\ind{stack}, we'll estimate the consumption of a ``typical
moderately-affluent person;''\label{typicalaffluent} I encourage you to tot up an estimate
of your {\em{own}\/} \ind{consumption}, creating your own personalized
left-hand stack too. Later on we'll also
find out the current {\em{average}\/} energy consumption of Europeans
and Americans.
\medskip
\medskip
\par
\noindent
{\mbox{\epsfbox{metapost/blah.1}}}
\smallskip
\par
As we estimate our consumption of energy for
heating, transportation, manufacturing, and so forth,
the aim is not only to compute a number for the left-hand stack of
our balance
sheet, but also to understand what each number depends on,
and how susceptible to modification it is.\index{efficiency!scope for improvement}
%
% \medskip% BREATH
% recently removed section heading
% \section{The sustainable production column}
In the right-hand, green stack, we'll add up the sustainable
production estimates for the United Kingdom.
This will allow us to answer the question ``can the \UK\ conceivably
live on its own renewables?''
Whether the sustainable energy sources that we put in the
right-hand stack are {\em{economically}\/}
feasible is an important question, but let's leave that question
to one side, and just add up the two stacks first.
Sometimes people focus too much on economic feasibility and
they miss the big picture.
For example, people discuss ``is wind cheaper than nuclear?''
and forget to ask
% *** CAPS? How
``how {\em{much}\/} wind is available?''
or ``how {much} uranium is left?''
% cut text to blah.tex; see metapost/blah.mp for the live text
% \newpage
%\noindent
The outcome when we add everything up might look like this:
%\begin{figure}[htbp]
\begin{oldcenter}
\begin{tabular}{cc}
%{\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.121}}} \\
\end{tabular}
\end{oldcenter}
% \begin{center}
%\mbox{\epsfxsize=2.3in\epsfbox{crosspad/balance4.ps}}
% \end{center}
%\end{figure}
\noindent
If we find consumption is much less than conceivable sustainable
production, then we can say ``good, {\em maybe\/} we can live sustainably;
let's look into the economic, social, and environmental
costs of the sustainable alternatives,\index{economic costs}\index{social costs}\index{environmental costs of renewables}\index{sustainable energy!social costs}\index{sustainable energy!environmental costs}
and figure out which of them deserve the most research and development;
% or government support;
if we do a good job, there {\em might\/} not be an energy crisis.''
%\vfillone
%\newpage
On the other hand, the outcome of our sums might look like this:
%\begin{figure}[htbp]
\begin{oldcenter}
\begin{tabular}{cc}
%{\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.127}}} \\
\end{tabular}
\end{oldcenter}
% \begin{center}
%\mbox{\epsfxsize=2.3in\epsfbox{crosspad/balance3.ps}}
% \end{center}
%\end{figure}
\noindent
-- a much bleaker picture. This picture says ``it doesn't matter what
the economics of sustainable power are: there's simply {\em{not enough}\/}
sustainable power to support our current lifestyle; massive change
is coming.''
% A third possibility is that the total consumption and production figures
% might come out similar.
%\begin{figure}[htbp]
%\mbox{\epsfbox{crosspad/balance2a.ps}}
%\end{figure}
% Given this picture, it's quite likely that massive change
% is required. We need to do our
% calculations again carefully to figure out what to do.
% \medskip% BREATH
\section{Energy and power}
% recently removed section heading
%\section{Units}
Most discussions of energy consumption and production
are confusing because of the proliferation of {\em\ind{units}}
in which energy and power are measured, from
``\tonnes\ of oil equivalent'' to ``terawatt-hours'' (TWh) and ``exajoules''
(EJ).
Nobody but a specialist has a feeling for what ``a barrel of oil'' or ``a
million BTUs''
means in human terms. In this
% One of the main contributions of this book will be to
book, we'll express everything in
a single set of personal units that everyone can relate to.
% My units will be `per person'
The unit of {\bf energy} I have chosen is the kilowatt-hour (kWh).
This quantity is called ``one unit''
on electricity bills, and it costs a domestic user about 10p
in the UK in 2008.
As we'll see, most individual daily choices
involve amounts of energy equal to small numbers of
kilowatt-hours.
% The retail value of one unit is about 2.5p.
When we discuss {\bf powers} (rates at which we use or produce energy),
the main unit will be
the kilowatt-hour per day (kWh/d). We'll also
occasionally use the watt (40\,W $\simeq$ 1\,kWh/d)
and the kilowatt (1\,kW $= 1000$\,W $=$ 24\,kWh/d), as I'll explain below.
The kilowatt-hour per day
is a nice
% cuddly
human-sized unit: most personal energy-guzzling activities
guzzle at a rate of a small number of
kilowatt-hours per day.%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
%\mbox{\epsfxsize=53mm\epsfbox{../../images/Bulbs60.jpg.eps}} \\
%\mbox{\epsfxsize=53mm\epsfbox{../../images/Bulbs60b.jpg.eps}} \\
% this next pic includes the boxes
%\lowres{\epsfxsize=53mm\epsfbox{../../images/Bulbs60cS.jpg.eps}}%
%{\epsfxsize=53mm\epsfbox{../../images/Bulbs60c.jpg.eps}} \\
\lowres{\epsfxsize=53mm\epsfbox{../../images/Bulbs60dS.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/Bulbs60d.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{Distinguishing energy and power.
Each of these 60\,W light bulbs has a {\em{power}\/} of 60\,W
when switched on;
it doesn't have an ``energy'' of 60\,W\@.
The bulb uses 60\,W of electrical
{\em{power}\/}
when it's on; it emits 60\,W of {\em{power}\/} in the form
of light and heat (mainly the latter).
}\label{fig.bulb60}
}
% For example, an electrical device that uses
% power at one kilowatt has a power consumption of 24
% kilowatt-hours per day.
For example, one 40\,W lightbulb, kept switched on all the time,
uses {\bf{one}} kilowatt-hour per day.
Some electricity companies include graphs
in their electricity bills, showing energy consumption
in \ind{kilowatt-hour}s per day.
I'll use the same unit for all forms of power, not just electricity.
Petrol consumption, gas consumption, coal consumption: I'll
measure all these powers in {kilowatt-hours per day}.
Let me make this clear: for some people, the word ``power'' means
only {\em{electrical}\/} energy consumption. But this book concerns
{\em{all}\/} forms of energy consumption and production, and
I will use the word ``power'' for all of them.
One \ind{kilowatt-hour per day} is roughly the power you could
get from one human \ind{servant}. The number of kilowatt-hours per day
you use is thus the effective number of servants you have working
for you.
% \medskip% BREATH
% recently removed section heading restored Fri 18/4/08
People use the two terms \ind{energy} and \ind{power}
interchangeably in ordinary speech, but in this book we must stick
rigorously to their scientific definitions.\index{confusion!power and energy}
{\em Power is the rate at which something
uses\index{power!definition}
energy}.\index{energy!contrasted with power}
Maybe a good way to explain \energycolor{energy} and \powercolor{power} is by an \ind{analogy}
with \energycolor{water}
and \powercolor{water-flow} from \uk{taps}{faucets}.\index{tap}\index{faucet}
If you want a drink of \ind{water}, you want a
{\em\energycolor{\ind{volume}}\/} of water -- \energycolor{one litre}, perhaps
(if you're thirsty).%
\amarginfignocaption{c}{
\begin{center}
\small
\begin{tabular}{c@{\hspace*{2em}}c}
\energycolor{volume} & \powercolor{flow} \\
is measured in &
is measured in \\
\energycolor{litres} & \powercolor{litres per minute} \\[0.3in]
\energycolor{energy} & \powercolor{power} \\
is measured in &
is measured in \\
\energycolor{kWh} & \powercolor{kWh per day} \\
\end{tabular}
\end{center}
}
%% *** SIMPLIFY?
When you turn on a \uk{tap}{faucet}, you
create a {\em\powercolor{\ind{flow}}\/} of water -- \powercolor{one litre per minute},
say, if the \uk{tap}{faucet} yields only a trickle;
or 10 litres per minute, from a more
generous \uk{tap}{faucet}.
You can get the same \energycolor{volume} (one litre) either
by running the trickling \uk{tap}{faucet} for one minute, or
by running the generous \uk{tap}{faucet} for one tenth of a minute.
The {\em\energycolor{\ind{volume}}\/} delivered in a particular time is
equal to the {\em\powercolor{\ind{flow}}\/} multiplied by the {\timecolor{\em{time}}}:
\[
\mbox{\energycolor{volume}} = \mbox{\powercolor{flow}} \times \mbox{\timecolor{time}}.
\]
We say that a {\em{flow}\/} is a {\em{rate}\/} at which {\em{volume}\/} is delivered.
If you know the volume delivered in a particular time, you get the
flow by dividing the volume by the time:
\[
\mbox{\powercolor{flow}} = \frac{ \mbox{\energycolor{volume}} }{ \mbox{\timecolor{time}} }.
\]
Here's the connection to energy and power.
\energycolor{\em{Energy}\/}
is like water \energycolor{\em{volume}}:
\powercolor{\em{power}\/} is like water \powercolor{\em{flow}}.
%
For example, whenever a toaster is switched on, it starts to consume
% one kilowatt of {\em{power}}.
\powercolor{\em{power}} at a rate of one kilowatt.
It continues to consume one kilowatt until it is switched off.
To put it another way,
% it consumes one kilojoule {\em per second\/}
% (a kilojoule
% is a unit of {\em{energy}});
% equivalently,
the toaster (if it's left on permanently)
consumes one kilowatt-hour (kWh) of energy per hour; it also
consumes 24 kilowatt-hours per day.
\amarginfignocaption{t}{
\begin{center}
\small
\begin{tabular}{c@{\hspace*{3em}}c}
\energycolor{energy} & \powercolor{power} \\
is measured in &
is measured in \\
\energycolor{kWh} & \powercolor{kWh per day} \\
or & or \\
\energycolor{MJ} & \powercolor{kW} \\
& or \\
% \energycolor{}
& \powercolor{W} (watts) \\
& or \\
% \energycolor{}
& \powercolor{MW} (megawatts)\\
& or \\
% \energycolor{}
& \powercolor{GW} (gigawatts) \\
& or \\
% \energycolor{}
& \powercolor{TW} (terawatts) \\
\end{tabular}
\end{center}
}%
The longer the toaster is on, the more \energycolor{energy} it uses.
You can work out the energy used by a particular activity by multiplying
the power by the duration:
\[
\energycolor{\mbox{energy}} = \powercolor{\mbox{power}} \times \timecolor{\mbox{time}} .
\]
The \ind{joule} is the standard international unit of energy,
but sadly it's far too small to work with.
% That's why I chose kilowatt-hours.
The kilowatt-hour is equal to
% 3600 kilojoules (
3.6 million joules (3.6 megajoules).
% Electricity companies often charge for electricity in
% \units\ of kilowatt-hours.
% One \unit\ (one kWh) costs about 10p in the UK; 10\cents\ in the USA.
% If you are already familiar with \units\ of electricity,
% then switching to kWh per day should not be too difficult:
% one kWh per day is equal to `one \unit\ per day'.
% Niagara = 5,720 m³/s
% = 110,000 m³ per minute
% ??? 20 million m**3 per hour ,
% shower = 15 litres/minute, 0.25 litres per second, 900 litres per hour.
Powers are so useful and important, they have something
that water flows don't have: they have their own special
units. When we talk of a flow, we might measure it in ``litres per minute,''
``gallons per hour,''
or ``cubic-metres per second;'' these units' names make clear that the flow
is ``a volume per unit time.''
% But if you talked about flows a lot, you might get bored repeating
% these long phrases. You might be tempted
% to coin a shorthand for a unit of flow, one
% that has the `per hour' built in -- for example, you might
% decide to call a flow of 1000 litres per hour `one \ind{triton}'.
%% ; or you might call 10 million cubic metres per hour `one niagara'.
% (`Blimey,
% the dripping taps in this hotel are wasting three tritons!'
% `I'm switching my one-triton \ind{shower-head} for a quarter-triton head.')
% For flows, no such shorthands are in widespread use.
% But for powers, such a shorthand has been coined.
A power of
{\em{one joule per second}\/} is called {\em{one watt}}.
1000 joules per second is called one kilowatt.
Let's get the terminology straight: the toaster uses one kilowatt.
It doesn't use ``one kilowatt per second.'' The ``per second'' is
already built in to the definition of the kilowatt:
one kilowatt means ``one kilojoule per second.''\nlabel{perper}
%
% When I say `the amount of electrical power the UK generates, on average, is
% getting on for 50 gigawatts (50\,GW)',
% some people ask `is that 50 gigawatts per year, or per day, or what?'
% But the `per' is already built in.
Similarly we say ``a nuclear power station generates
one gigawatt.'' One gigawatt, by the way, is one
billion watts, one million kilowatts,
or 1000 megawatts. So one gigawatt is a million toasters.
And the ``g''s in gigawatt are pronounced hard,\index{pronunciation}
the same as in ``\ind{giggle}.'' And, while I'm tapping the blackboard,
we capitalize the ``g'' and ``w'' in ``\ind{gigawatt}''
only when we write the abbreviation ``\ind{GW}.''\index{capitalization}
Please, never, ever
say ``one kilowatt per second,''\label{dontsayper}
``one kilowatt per hour,'' or ``one kilowatt per day;''
none of these is a valid measure of power.
The urge that people have to say ``per something'' when talking about
their toasters is one of the reasons
I decided to use the ``kilowatt-hour per day'' as my unit of power.
I'm sorry that it's a bit cumbersome to say and to write.
% The national average for shower head flow rates is 2.2222 gpm
% US I guess . That is 504 litres per hour.
Here's one last thing to make clear:
if I say ``someone used a \ind{gigawatt-hour} of energy,'' I am simply telling
you {\em{how much}\/} energy they used, not {\em{how fast}\/} they used it.
\label{pGWh}Talking about a gigawatt-hour {\em{doesn't}\/} imply the energy was used
{\em{in one hour}}.
%% , for example.
You could use a gigawatt-hour of energy by
% getting one nuclear power station to power
switching on one million
toasters for one hour,
% ; but you could also use a gigawatt-hour
or
by switching on 1000 toasters for 1000 hours.
% (also known as 40 days and 40 nights).
% Just as the volume of one litre ...
As I said, I'll usually quote powers in kWh/d {\em{per person}}.
One reason for liking these personal units is that it
makes it much easier to move from talking about the UK to talking about
other countries or regions.
For example, imagine we are discussing \ind{waste incineration}
and we learn that UK waste incineration delivers
a power of 7\,TWh per year
% terawatt-hours
% \,TWh/y
% (250\,MW) 6.8 TWh
and that
\ind{Denmark}'s waste incineration delivers
10\,TWh per year.\marginfignocaption{
\small
1\,TWh (one terawatt-hour)
is equal to one billion kWh.
}
% kilowatt-hours).
% \,TWh/y.
% from EUROSTAT
% Incineration capacity of Denmark is 2310 thousand tons per year.
%# in 1998
%# 74% of MSW is incinerated, there are 31 incins
% UK: 3670 thousand tons per year, 8%, 31. (in 1998)
%% http://www.defra.gov.uk/environment/waste/wip/newtech/pdf/incineration.pdf
%% Raw MSW typically has an energy content of
%9 - 11MJ/kg, whereas a Refuse Derived Fuel (RDF) can have an
%energy content of 17MJ/kg. MAXIMUM elec effiency of
% electricity-only incinerator is 27% . Typical is 14-24%.
% Best heat recovery is 80% if heat-only
% see _balance.tex
%
%% this ref was useless:
%% http://www.risoe.dk/rispubl/reports/ris-r-1608_82-93.pdf
%% In Denmark 27% of the waste produced in 2004 was incinerated for heat and power
%% production. Of the remaining amounts, 64% was recycled and only 8% land filled. [1]
%% In Denmark the 34 Danish waste incineration plants contribute with 4% of the Danish
%% electricity production and 18% of the heat production. 75% of the waste resource
%% LHV of mixed waste is
%% 10.5 MJ/kg [7]
%% of organic waste 5.7 MJ/kg
%% Denmark: total waste is 10 TWh of energy (including heat , not just elec )
Does this help us say whether Denmark incinerates
``more'' waste
than the UK?
While the total power produced from waste in each country
may be interesting,
% and indeed Denmark's total is a little bigger,
I think that what we usually want to know is
the waste incineration {\em{per person}}.
% 5.17564 0.31311
(For the record, that is: Denmark, 5\,kWh/d per person;
UK, 0.3\,kWh/d per person. So Danes incinerate
about 13 times as much waste as Brits.)
To save ink, I'll sometimes abbreviate ``per person'' to ``/p''.
By discussing everything per-person from the outset, we
end up with a more transportable book, one that will hopefully
be useful for sustainable energy discussions worldwide.
\section{Picky details}
\beforeqa
\qa{{Isn't energy conserved?}
We talk about
% humans fundamental
``using'' energy, but doesn't one of the laws of nature say
that energy can't be created or destroyed?\index{laws of physics!conservation of energy}\index{physics!conservation of energy}\index{conservation of energy}\index{energy!conservation}}
Yes, I'm being imprecise. This is really a book about
{\em\ind{entropy}\/} --
a trickier thing to explain.
When we ``use up'' one kilojoule of energy, what we're really doing is taking
one kilojoule of energy in a form that has
{\em{low entropy}\/} (for example, electricity),
and {\em{converting}\/} it into an exactly equal amount of energy in another
form, usually one that has much higher entropy (for example, hot air
or hot water).
When we've ``used'' the energy, it's still
there; but we normally can't ``use'' the energy over and over again, because
only {\em{low entropy}\/} energy is ``useful'' to us.
Sometimes these different grades of energy are distinguished
by adding a label to the units: one \kWhe\ is one kilowatt-hour of electrical
energy -- the highest grade of energy. One \kWhth\ is one
kilowatt-hour of thermal energy -- for example the energy in ten litres of
boiling-\ind{hot water}.
%% 80 * 4.2 * 1000 * 10 J = 1 kWh
Energy lurking in higher-temperature things is more useful
(lower \ind{entropy}) than energy in \ind{tepid} things. A third grade of energy
is \ind{chemical energy}. Chemical energy is high-grade energy like electricity.
It's a convenient but sloppy shorthand to talk about the energy
rather than the entropy,
and that is what we'll do most of the time in this book.
Occasionally, we'll have to smarten up this sloppiness; for
example, when we discuss \ind{refrigeration}, \ind{power station}s,
\ind{heat pump}s, or
\ind{geothermal power}.
%, we'll have to talk about the entropic view of what's going on.
\qa{{Are you comparing apples and oranges?}
Is it valid to compare different forms of energy
such as the chemical energy that is fed into a petrol-powered
car and the electricity from a wind turbine?}
By comparing consumed energy with conceivable produced energy,
I do not wish to imply that all forms of energy are equivalent
and interchangeable. The electrical energy produced by a wind turbine is of
no use to a petrol engine; and petrol is no use if you
want to power a television. In principle, energy can be converted
from one form to another, though conversion entails losses.
Fossil-fuel power stations, for example, guzzle {\em{chemical energy}\/} and
produce {\em{electricity}\/} (with an efficiency of 40\% or so).
And aluminium plants guzzle {\em{electrical energy}\/}
to create a product with high {\em{chemical energy}\/}
-- aluminium (with an efficiency of 30\% or so).
% The theoretical minimum is 6.36 kWh/kg
% http://electrochem.cwru.edu/ed/encycl/art-a01-al-prod.htm
% In practice they use about 12 kWh per kg of electr. Hall-Heroult process
% (just the energy for the electrolysis)
% in stuff.tex I say 15 kWh/kg is the electrolysis cost and 3-4.4 extra of carbon
%
In some summaries of energy production and consumption,
all the different forms of energy are put into the same
units, but
multipliers are introduced, rating electrical energy
from hydroelectricity for example as being worth 2.5 times more
than the chemical energy in oil. This
bumping up of electricity's effective energy value can be justified
by saying, ``well, 1\,kWh of electricity is equivalent to 2.5\,kWh
of oil, because if we put that much oil into a standard power station
it would deliver 40\% of 2.5\,kWh, which is 1\,kWh of electricity.''
%
In this book, however, I will usually use a one-to-one conversion
rate when comparing different forms of energy. It is {\em{not}\/} the case
that 2.5\,kWh of oil is inescapably equivalent to 1\,kWh of electricity;
that just happens to be the perceived exchange rate
in a worldview where oil is used to make electricity.
% from the point of
% view of one present-day technology.
Yes, conversion of chemical energy to electrical energy
is done with this particular inefficient exchange rate.
But \ind{electrical energy} can also be converted
to \ind{chemical energy}.
In an alternative world (perhaps not far-off) with relatively plentiful
electricity and little oil, we might use electricity to make liquid fuels;
in that world we would
surely not use the same \ind{exchange rate} -- each kWh of gasoline
would then
cost us something like 3\,kWh of electricity!
I think the timeless and scientific
way to summarize and compare energies is to hold
1\,kWh of chemical
energy equivalent to 1\,kWh of electricity.
My choice to use this one-to-one conversion rate means that some of
my sums will look a bit different from other people's. (For
example, \ind{BP}'s {\tem{Statistical Review of World Energy}\/}
rates 1\,kWh of electricity as
equivalent to $100/38 \simeq 2.6$\,kWh of oil; on the other
hand, the government's {\tem{Digest of UK Energy Statistics}\/}
uses the same one-to-one conversion rate as me.)\nlabel{pDUKES}
% 2008 they assume 38% efficiency
And I emphasize again, this choice does not imply that I'm suggesting
you could convert either form of energy directly into the other.
Converting chemical energy into electrical energy always
wastes energy, and so does converting electrical into chemical energy.
\section{Physics and equations}
Throughout the book, my aim is not only to work out numbers
indicating our current energy consumption
and conceivable sustainable production, but also
to make clear {\em what these numbers depend on}.
Understanding what the numbers depend on is essential
if we are to choose sensible policies to change any of the
numbers.
Only if we understand the physics behind energy consumption
and energy production can we assess assertions such as
``cars waste 99\% of the energy they consume; we could redesign
cars so that they use 100 times less energy.''
Is this assertion true? To explain the answer, I
%% will
will need to use equations\index{energy!kinetic}
%% formulae
like
\[
\mbox{\ind{kinetic energy} $=\displaystyle \frac{1}{2} m v^2 $}.
\]
However, I recognize that to many readers, such formulae
are a foreign language.
So, here's my promise:
{\em I'll keep all this foreign-language stuff
in technical chapters at the end of the book.}
Any reader with a high-school/secondary-school qualification in
maths, physics, or chemistry should
% Maths, Physics, or Chemistry should be
% able to follow these arguments in detail.
enjoy these technical chapters.
The main thread of the book (from page \pageref{pone} to page \pageref{pENDone}) is intended to be
accessible to everyone who can
add, multiply, and divide.
It is especially aimed at our dear elected
and unelected representatives,
the Members of Parliament.
% BREATH
% \medskip
%\section{Should we discuss energy, or climate change?}
% {\em Move this para later?}
% In the current discussion of the global energy crisis,
% attention tends to focus on climate change and \COO\ emissions.
% In \partI, we focus on energy. One reason for focussing
%% spell???? SPELL???
% on energy
% is that even if the \COO\ problem went away, I feel we
% would still have a sustainable-energy problem.
% We'll come back to the topic of \COO\ in \partII.
%\section{One last point, before we begin}
{One last point, before we get rolling:}
%%% *** CRIT
% I'm not an expert in any of the topics in this book.
I don't know everything about energy.
I don't have all the answers, and the numbers I offer are
open to revision and correction. (Indeed I expect corrections
and will publish them on the book's website.)
%
The one thing I {\em{am}\/} sure of is that the answers to our sustainable
energy questions will involve {\em{numbers}}; any sane discussion of
sustainable energy requires numbers. This book's got 'em, and it shows
how to handle them. I hope you enjoy it!
%\newpage
%\small
\beginfullpagewidth\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
% \noindent
\item[page no.]
%\item[\pageref{pGWh}]
% {\sc Talking about a gigawatt-hour doesn't imply the energy was used
% {\em{in one hour}}.}
% I emphasize this point, because this energy/power distinction
% seems to confuse many people
% -- including energy consultants Deloitte--Touche!
% another example in today's Sun 9/12/07 Observer corrections --- they corrected
% 12 GW to 74 GW ``annually''
\item[\npageref{perper}]
{\nqs{The ``per second'' is
already built in to the definition of the kilowatt.}}
Other examples of
units that, like the watt, already have a ``per time'' built in are the knot
--
``our yacht's speed was ten knots!''
(a knot is one nautical mile {\em per\/} hour); the hertz
-- ``I could hear a buzzing at 50 hertz'' (one hertz is a frequency of
one cycle {\em{per}\/} second); the ampere
-- ``the fuse blows when the current is higher than 13 amps''
({\em{not}\/} 13 amps per second);
and the horsepower -- ``that stinking engine delivers
50 horsepower'' ({\em{not}\/} 50 \ind{horsepower} per second,
{nor} 50 horsepower per hour,
{nor} 50 horsepower per day,
just 50 horsepower).
\item[\npageref{dontsayper}]
{\nqs{Please, never, ever say ``one kilowatt per second.''}}
There are specific, rare exceptions to this rule.
% If you run a solar-power factory that manufactures
% solar power stations then it would be natural to describe your factory's output
% by saying `we produce one gigawatt per year'.
% Similarly, i
If talking about a growth in demand for power, we might say
``British demand is growing at one gigawatt per year.''
In \chref{ch.storage} when I discuss fluctuations in wind power,
I will say ``one morning,
the power delivered by Irish windmills fell at a rate of
84\,\MW\ per hour.'' Please take care! Just one accidental
syllable can lead to confusion:
for example, your electricity meter's reading
is in kilowatt-hours (kWh), {\em not} `kilowatts-per-hour'.\smallskip
\end{notelist}
% \pref{powergrid} and
I've provided a chart on \pref{endGrid} to help
you translate between kWh per day per person
and the other major units in which powers are discussed.
%\medskip
%\par
\normalsize
\ENDfullpagewidth
%\chapter{Cars}
%\newpage
%\noindent
%\mbox{\epsfbox{metapost/stacks.20}} %% usa or south africa
\rset\chapter{\rcol{Cars}}
%\chapter[Cars]{\mbox{\epsfxsize=4.3in\epsfbox{crosspad/cars.ps}}}
\label{ch.cars}\label{ch.car}
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
%\mbox{\epsfxsize=53mm\epsfbox{../../images/CarsBMWSpaceship4.jpg.eps}} \\
\lowres{\epsfxsize=53mm\epsfbox{../../images/CarsBMWSpaceship3S.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/CarsBMWSpaceship3.jpg.eps}} \\
%\lowres{\epsfxsize=53mm\epsfbox{../../images/CarElephantS.jpg.eps}}%
%{\epsfxsize=53mm\epsfbox{../../images/CarElephant.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
Cars. A red \ind{BMW} dwarfed by a \ind{spaceship}
from the \ind{planet Dorkon}.
}
}
For our first chapter on consumption, let's
study that icon of modern civilization:
% that symbol of
% individual freedom:
the \ind{car} with a lone person in it.
% invalid carriage.
% Invalid carriages give enhanced
% mobility to physically-disabled people.
% Invalid carriages are also popular with able-bodied people,
% who tend to call these one-tonne metal boxes `cars'.
% 50 km is 31 miles.
How much power does a regular car-user consume?
Once we know the conversion rates, it's simple arithmetic:
\beqa
\mbox{\begin{tabular}{@{}c@{}}energy used\\[-0.1mm]per day\end{tabular}} \!&\!=\!&\! \frac{
\mbox{distance travelled per day}
}{ \mbox{distance per unit of fuel }}
\,\times\, \mbox{energy per unit of fuel} .
% \\
\eeqa
For the {\bf{distance travelled per day}}, let's use 50\,\km\ (30 miles).\label{pageAveragecar}
% 60 miles = 96.56
% 100 kilometers = 62.1371192 miles 50 km is 31 miles
% 50 km/d is 18,000 km per y
For the {\bf{distance per unit of fuel}}, also known as the {\bf\ind{economy}}
of the car, let's use 33 miles per UK gallon (taken from an advertisement
for a\label{mileage}
% diesel-engined
family car):
%% in today's newspaper).
%% box this
\[
33\, \mbox{miles per imperial gallon}
%%% = 27.5 \,\mbox{miles per US gallon}
%% 27.478236
\simeq 12\,\km\ \per\ \litre.
\]
% 33 * (miles per Imperial gallon) = 11.6821994
(The symbol ``$\simeq$'' means ``is approximately equal to.'')
%% figure for motor gasoline: 44,000 kJ/kg (net cal value)
%% biodiesel 37,000 kJ/kg
What about the {\bf{energy per unit of fuel}}
(also called the {\bf{calorific value}} or {\bf{energy density}})?
Instead of looking it up,\index{calorific value!butter}
it's fun to estimate this sort of quantity
by a bit of lateral thinking. Automobile fuels (whether
diesel or petrol)\index{energy density!butter}\index{calorific value!fuel}
%% and aviation fuels
are all hydrocarbons;\index{energy density!fuel}\index{fuel!energy density}
and \ind{hydrocarbon}s can also be found on our breakfast table,
with the calorific value conveniently written on the side:
roughly 8\,kWh\index{butter!calorific value}\index{fuel!calorific value}
% 30\,000\,\kJ\
per \kg\ (\figref{fig.butter}).
\amarginfig{b}{
\begin{center}
\begin{tabular}{c}
\lowres{\epsfxsize=50mm\epsfbox{../../images/butterS.jpg.eps}}%
{\epsfxsize=50mm\epsfbox{../../images/butter.eps}} \\
%\mbox{\epsfxsize=50mm\epsfbox{../../images/butterNutrition2.eps}} \\
%\mbox{\epsfxsize=50mm\epsfbox{../../images/butter/energy2.eps}} \\
\lowres{\epsfxsize=50mm\epsfbox{../../images/butter/energy1S.jpg.eps}}%
{\epsfxsize=50mm\epsfbox{../../images/butter/energy1.eps}} \\
\end{tabular}
\end{center}
\caption[a]{%%% for BUTTER FLOATS figure see _cars.tex
Want to know the energy
in car fuel?
Look at the label on a pack of \ind{butter} or \ind{margarine}.
The \ind{calorific value} is 3000\,kJ per 100\,g,
or
% 30\,000\,\kJ\ per \kg.
about 8\,kWh per kg.
}
\label{fig.butter}
}%
%% energy density of gasoline
%% http://hypertextbook.com/facts/2003/ArthurGolnik.shtml
%% 12.7 kWh/kg or 8.76kWh/l
Since we've estimated the economy
of the car in miles per unit {\em{volume}\/} of fuel,
we need to express the
\index{energy density}\ind{calorific value} as an energy per unit {\em{volume}}.
To turn our fuel's ``8\,kWh
% 30\,000\,\kJ\
per \kg'' (an energy per unit
{\em{mass}})
into an energy per unit volume, we need to know the
density of the fuel.
What's the density of \margarine? Well, \margarine\ just\label{butter}
floats on water, as do fuel-spills, so its density must be a
little less than water's, which is 1\,\kg\ per litre.
If we guess a density of 0.8\,\kg\ per litre\label{pageDensity},
%% 0.7 is a better figure for gasoline
%% volume of one kilogram
% and assume \margarine\ and \ind{petrol} are the same,
we obtain
a \index{energy density}\ind{calorific value} of:
\[%beq
% 30\,000\,\kJ\,
8\,\kWh\ \per\ \kg \times 0.8\,\kg \ \per\ \litre
\simeq
% 24\,000\,\kJ
7\,\kWh\ \per\ \litre .
\]%eeq
% Putting this into our preferred energy unit, the kilowatt-hour
% ($1\,\kWh = 3600\,\kJ$),
% the calorific value of fuel is estimated to be about 7\,\kWh\,per\,litre.
Rather than willfully perpetuate an inaccurate estimate,
let's switch to the actual value, for petrol, of
% 8.8\,\kWh\,per\,litre. 9.7
10\,kWh per litre.\nlabel{pageFuel}
%
\beqa
\mbox{energy per day}\! &\!=\!& \!\frac{
\mbox{distance travelled per day} }
{ \mbox{distance per unit of fuel }}
\times \mbox{energy per unit of fuel}
\\
&\!=\!& \frac{ 50 \,\km / \uday }
{{ 12 \,\km / \litre }} \times 10 \,\kWh /\litre
\\
&\!\simeq\!& \Red{40 \,\kWh / \uday} .
\eeqa
% 80.8 accurate ; 83.3 is what you get from this calculation
%
Congratulations!
\amarginfig{b}{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}cc}
{\small\sc Consumption}& {\small\sc Production}\\
\mbox{\epsfbox{metapost/stacks.21}} & \\
%% {\mbox{\epsfbox{crosspad/cars3.ps}}} & ? \\
\end{tabular}
\end{center}
% }{
\caption[a]{Chapter \protect\ref{ch.car}'s conclusion:
a typical car-driver uses about 40\,kWh per day.
}\label{fig.carCon}
}%
% \end{figure}
We've made our first estimate of consumption.
% For ease of memorization, let's round this figure to
% 70\,\kWh\ per day.
I've displayed this estimate in the left-hand stack in \figref{fig.carCon}.
% Subsequent chapters will alternate add to the right-hand stack
The red box's height represents 40\,kWh per day per person.
This is the estimate for a typical car-driver driving a
typical car today. Later chapters will discuss
the {\em{average}\/} consumption of all the people in Britain, taking
into account the fact that not everyone drives. We'll also
discuss in Part II what the
consumption {\em could\/} be, with the help of other technologies
such as electric cars.
% come back to the question of the car's economy, asking:
Why does
the car deliver 33 miles per \uk{gallon}{imperial gallon}? Where's that energy going?
Could we manufacture cars that do 3300 miles per gallon?
If we are interested in trying to reduce cars' consumption,
we need to understand the \ind{physics} behind cars' consumption.
% We've not finished with cars yet. In a later chapter we'll
% These are questions that can be addressed with the
% help of a
%% *** TENSE CONSISTENCY?
These questions are answered in the accompanying
% appendix
technical chapter
\ref{ch.cars2} (\pref{ch.cars2}), which provides a
cartoon theory of cars' consumption.
I encourage you to read the
% appendices
technical chapters
if formulae
like $\frac{1}{2} m v^2$ don't give\index{formula!kinetic energy}
you medical problems.
% The appendices make use of formulae like $\frac{1}{2} m v^2$;
% I encourage you to read the appendices if such formulae don't give
% you medical problems.
Chapter \protect\ref{ch.car}'s conclusion:
a typical car-driver uses about 40\,kWh per day.
% Now we need to find out about sustainable production.
%
Next we need to get the sustainable-production stack going, so
we have something to compare this estimate with.
\section{Queries}
\qa{What about the energy-cost of {\em{producing}\/}
the car's fuel?}{
Good point.
When I estimate the energy consumed by a particular
activity, I tend to choose a fairly tight ``\ind{boundary}''
around the activity.
This choice makes the estimation easier, but I agree that
it's a good idea to try to estimate the full energy impact of an activity.
It's been estimated that making each unit of petrol
requires an input of 1.4 units of oil and other primary fuels
\citep{TreloarLoveCrawford}.
%% *** MJB says to check Shell for LCA on this. He predicts 10 or 15%
}
\qa{What about the energy-cost of {{manufacturing}}
the {\em{car}}?}{
Yes, that cost fell outside the boundary of this calculation too.
We'll talk about car-making in \chref{ch.stuff}.
}
% \newpage
% \newpage
%\beginfullpagewidth
\small
\section*{Notes and further reading}
\nopagebreak
\beforenotelist
\begin{notelist}
\item[page no.]
% In USA 77% of people drive to work
% Norfolk: 213k out of 359k working get to work by car or van
% In England and Wles 55% drive car or van to work. 6.3% are passengers in a car
% or van
\item[\npageref{pageAveragecar}]
{\nqs{For the {{distance travelled per day}}, let's use 50\,km.}}
This corresponds to 18\,000\,km (11\,000 miles) per year.
\amarginfig{b}{
\begin{center}
\mbox{\epsfxsize=53mm\epsfbox{../data/transportmode.eps}} \\
\end{center}
\label{fig.transportmode}
\caption[a]{
How British people \ind{travel} to work,\index{data!commuting}\index{commuting, data}
according to the 2001 census.
}
}%
Roughly half of the British population drive to work.
% Average distance travelled per person per year by car
% is 3660 miles as driver (2033 as passenger) 16km
The total amount of car travel in the UK
is 686 billion passenger-km per year,
% 2006
which
corresponds to an ``average distance travelled by car per
\ind{British person}''\index{average travel}\index{travel!average}
of 30\,km per day.
Source: Department for Transport
% 686 billion passenger km per year / 60e6 /365.25
% website the average distance travelled
%> in a car per year per person is about 5,500 miles (
% Section 2.4 of
%% http://www.dft.gov.uk/stellent/groups/dft_transstats/documents/page/dft_transstats_026290.hcsp
%% http://tinyurl.com/wqm2z
% this link has gone bad
% new link is
\tinyurl{5647rh}{http://www.dft.gov.uk/pgr/statistics/datatablespublications/tsgb/}.
% \tinyurl{wqm2z}{http://www.dft.gov.uk/stellent/groups/dft_transstats/documents/page/dft_transstats_026290.hcsp}.
% {\url{http://{\breakhere}www.{\breakhere}dft.{\breakhere}gov.{\breakhere}uk/{\breakhere}stellent/{\breakhere}groups/{\breakhere}dft\_transstats/{\breakhere}documents/{\breakhere}page/{\breakhere}dft\_transstats\_026290.hcsp}}
As I said on \pref{typicalaffluent},
I aim to estimate the consumption of a ``typical
moderately-affluent person'' -- the consumption that many people
aspire to.
Some people don't drive much. In this chapter,
I want to estimate the energy
consumed by someone who chooses to drive, rather than depersonalize
the answer by reporting the UK average, which mixes together the drivers
and non-drivers.
% If you'd prefer to use different figures, feel free.
If I said ``the average use of energy for car driving
in the UK is 13\,kWh/d per person,'' I bet
%%%% CORRECT 24 to 13 (at pump) or 18 (upstream primary energy cost)
%%%% source http://www.dft.gov.uk/pgr/statistics/datatablespublications/tsgb/
%%% see http://www.inference.phy.cam.ac.uk/wiki/sustainable/en/index.php/Chapter_3
%%% 21.68e6 tonnes per year * 13 kWh per kg / 60e6 in kWh per day
%%% 12.86 kWh per day per person (not including upstream costs)
%%% The total petroleum used by all road transport is 38.5 Million tonnes per year. (about 23 kWh per day per person).
some people would misunderstand and say: ``I'm a car driver
so I guess I use 13\,kWh/d.''
%% 2006: 511 billion vehicle km
%% from http://www.dft.gov.uk/pgr/statistics/datatablespublications/trends/current/transporttrends2007
%% of which cars:
%% 402 billion vehicle kilometres. (2006)
%% average car occupancy is 1.58 (2006)
%% average traffic speed in urban areas is 21 mph on peak, and 24 mph off peak.
%% in London, average traffic speed in urban areas is 15 mph morning peak, and 18 mph off peak.
%% there are 30 million private and light goods vehicles . and 33.3M total of all vehicles
%% 25% of households have no car
%% 30% of adults have no driving license
\setcounter{latestnotepage}{0}% hack to ensure page number given
\item[\npageref{mileage}]
{\nqs{\ldots\ let's use 33 miles per UK gallon.}}
In the European language, this is 8.6\,litres per 100\,km.
% 8.56.
% (I got this number
% from an advertisement
% for a family car).}
33 miles per gallon was the average for UK cars in 2005
\tinyurl{27jdc5}{http://www.dft.gov.uk/pgr/statistics/datatablespublications/
energyenvironment/
tsgb-chapter3energyandtheenvi1863}.
% edited this URL to fix problem (added -)
Petrol cars have an average fuel consumption of 31\,mpg; diesel cars, 39\,mpg;
new petrol cars (less than two
years old), 32\,mpg \citep{TSGB}.\label{tabCar80}
% Is this too low a figure?
% SMMT figures also show that the average Combined
% economy of all new registrations has risen from
% 42mpg in 2004 to 43.4mpg in 2006.
% For comparison,
% The website of
\ind{Honda}, ``the most fuel-efficient auto company in America,''
records that its fleet of new cars sold in 2005 has an average
top-level fuel economy of
% 29.2 miles per US gallon, which is
35 miles per UK gallon
%% which is 12\,\km \,\per\, \litre.
\tinyurl{28abpm}{http://corporate.honda.com/environmentology/}.
\item[\npageref{pageDensity}]
{\nqs{Let's guess a \ind{density} of 0.8\,kg\ per litre.}
} \Gasoline's density is 0.737.
Diesel's is 0.820--0.950
{\tinyurl{nmn4l}{http://www.simetric.co.uk/si_liquids.htm}}.
\item[\npageref{pageFuel}]
{\nqs{\ldots\ the actual value of
10\,kWh per litre}.}
ORNL \tinyurl{2hcgdh}{http://cta.ornl.gov/data/appendix_b.shtml} provide
the following \ind{calorific value}s:
\ind{diesel}: 10.7 kWh/l; \ind{jet fuel}: 10.4 kWh/l; \ind{petrol}\index{gasoline}:
9.7 kWh/l.
\marginpar{\small
%\margintab{
\begin{tabular}{cc}\toprule
\multicolumn{2}{c}{\sf{\index{energy density}\ind{calorific value}s}} \\
\midrule
petrol & 10\,\kWh\ per litre\\
diesel & 11\,\kWh\ per litre\\
\bottomrule
\end{tabular}
% \caption[a]{ Facts worth remembering: petrol and diesel. }
}
When looking up calorific values, you'll find ``gross calorific
value'' and ``net calorific value'' listed (also known
as ``\ind{high heat value}'' and ``\ind{low heat value}'').\index{calorific value!net}
These differ by only 6\%
for motor fuels, so it's not crucial to distinguish them here,
but let me explain anyway. The \ind{gross calorific value}\index{calorific value!gross}
is the actual
\ind{chemical energy}\index{energy!chemical}
released when the fuel is burned.
One of the products of \ind{combustion} is water, and in most engines
and power stations, part of the
energy goes into vaporizing this water.\index{energy!of vaporization}
The net calorific value measures how much energy is left over
assuming this energy of vaporization is discarded and wasted.
When we ask ``how much energy does my lifestyle consume?'' the
\ind{gross calorific value} is the right quantity to use.
The \ind{net calorific value},
on the other hand, is of interest to a power station \ind{engineer},
who needs to decide which fuel to burn in his power station.
Throughout this book I've tried to use gross calorific values.
A final note for party-pooping \ind{pedant}s who say ``\ind{butter} is not
a \ind{hydrocarbon}'':
OK, butter is not a {\em{pure}\/} hydrocarbon; but it's a good approximation
to say that the main component of butter is long hydrocarbon chains, just
like petrol.
The proof of the pudding is, this approximation got us within 30\% of the
correct answer. Welcome to \ind{guerrilla physics}.
% The gross calorific value of \ind{DERV} is 45.5\,GJ/tonne;
% of aviation fuel, 46.2; of motor spirit, 47\,GJ/tonne
%{\tinyurl{ybh97n}{http://www.cefic.be/sector/shared/ecoprofile/appendix/a04.htm}}.
% The net calorific value is 6\% smaller.
% Not that it makes any difference,
% but in these calculations I use the gross calorific value, since that's
% the energy guzzled.
% Thus the calorific value of \ind{petrol} is 10\,\kWh\,per\,litre.
% For easy memorization, I've rounded this figure to 9\,\kWh\,per\,litre.
%% gross cal value of gasoline is 45.85 MJ/kg; net cal val=42.95
%% ROUGHLY 12 kWh/ kg
%% 6% difference.
% Diesel's calorific value is slightly higher\index{diesel} -- about 11\,kWh\,per\,litre.
% Correction Tue 11/12/07:
% Wikipedia says petrol is 34.6 megajoules per litre, which is 9.61 kWh per litre.
% So I think petrol should be 10 and diesel (38.6 MJ/l) 11 kWh/l. (10.7)
% petrol : 44.4MJ/kg; diesel 45.4MJ/kg.
% This bumps up all my car figures by 10\%. DONE
% Wikipedia's source is \tinyurl{2hcgdh}{http://cta.ornl.gov/data/appendix_b.shtml}.
% diesel: 138700 Btu/gal ; jet fuel 135000 Btu/gal ; gasoline 125000 Btu/gal
% 10.74 kWh/l 10.45 kWh/l 9.7 kWh/l
% 10.7 kWh/l 10.4 kWh/l 9.7 kWh/l
% 37.6 MJ/l
\end{notelist}
\normalsize
\normalsize
%\ENDfullpagewidth
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm\epsfbox{../../images/ExhaustPipe.jpg.eps}} \\
\end{tabular}\label{Claire1}
\end{center}
% \caption[a]{ }
}
%Commute for an office
%
%For that Exeter branch of PF, their average commute per person per
%workday was 30 (averaged over 75 employees at the site, using
%post-codes from a travel survey), with 47 work weeks per year.
\gset\chapter{\gcol{Wind}}
\label{ch.wind}
%\chapter[Wind]{\mbox{\epsfxsize=4.3in\epsfbox{crosspad/wind.ps}}}
%% http://www.polmontweather.co.uk/windspd.htm
% The UK has the best and most geographically diverse wind resources in Europe,
\myquote{%
The UK has the best wind resources in Europe.
}{Sustainable Development Commission}
% page 12 of their wind document.
\myquote{%
Wind farms will devastate the countryside pointlessly.
}{{James Lovelock}}
% Monday Jan 27th, 2006.
%\end{quote}
% \noindent
How much \ind{wind} power could we plausibly generate?
%
\amarginfignocaption{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/AngleOnWindS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/AngleOnWind.jpg.eps}}} \\
\end{tabular}
\par\vspace{0pt}
\end{center}
% \caption[a]{}
\label{germanWindmill}
}
We can make an estimate of the
potential of {\em{on-shore}\/} (land-based)
wind in the United Kingdom by multiplying the average power per unit land-area of a
{\windfarm} by the \ind{area per person} in the \UK:
\[%beq
\mbox{power per person}
=
\mbox{\OliveGreen{wind power per unit area}}
\times \mbox{area per person} .
\]%eeq
% Appendix
Chapter \ref{ch.wind2} (\pref{ch.wind2})
explains how to estimate the power per unit area of a \ind{\windfarm} in
the \UK.\index{power density!wind farm}
If the typical windspeed
is 6\,m/s (13\,miles per hour, or 22\,km/h),
%% 13.4 mph
%% 21.6 kph
the power per unit area of \windfarm\ is about \OliveGreen{2\,\Wmm}.\par
\begin{figure}[hbtp]
\figuremargin{
\begin{center}
\mbox{\epsfxsize=\textwidth%
\mono{\epsfbox{../data/cambridge/mono/Cam2006.eps}}%
{\epsfbox{../data/cambridge/Cam2006.eps}}%
%%% made by load 'gnu'
}
\end{center}
}{
\caption[a]{Cambridge\index{data!wind!Cambridge} mean wind speed in metres per second, daily (red line),\index{wind!data}
and half-hourly (blue line) during 2006. See also \figref{fig.windhisto}.
% Thanks to Digital Technology Group, Computer Laboratory, Cambridge.
\medskip
\par
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/wind0.eps,angle=270}}% cairngorm and cambridge
}
\label{fig.camb.wind}
}
\end{figure}
\noindent
This figure of 6\,m/s is probably an over-estimate for
many locations in Britain.
For example,
%\marginpar{
%\begin{center}
%\end{center}
%\label{pwind0}
%}
\figref{fig.camb.wind}
shows daily \ind{average windspeeds}\index{windspeed!Cambridge} in Cambridge
during 2006.
%
The daily average speed reached 6\,m/s on only about 30 days
of the year -- see \figref{fig.camb.wind2} for a histogram.
But some spots do have windspeeds above 6\,m/s -- for example, the summit
of Cairngorm in Scotland (\figref{fig.cairngorm}).
Plugging in the British population density: 250 people per
square kilometre, or 4000 square metres per person, we find that
wind power could%
\begin{figure}[hbtp]
\figuremarginb{
\begin{center}
\mbox{\epsfxsize=\textwidth%
\mono%
{\epsfbox{../data/cairngorm/mono/CairngormWind2006.eps}}%
{\epsfbox{../data/cairngorm/CairngormWind2006.eps}}%
}%
\end{center}
}{
\caption[a]{Cairngorm\index{data!wind!Cairngorm} mean wind speed in metres per second,\index{wind!data}
% daily (heavy line),
% and half-hourly (light line),
during six months of 2006.
\index{windspeed!Cairngorm}
}
\label{fig.cairngorm}
\label{pwind0}
}
\end{figure}
generate
\[
% 2.2 \,\W/\m^2 \times 4000 \,\m^2/\person \:\simeq\:
% 9\,\kW \,\per\,\person,
2 \,\Wmm \times 4000 \,\m^2/\person \: = \:
8000\,\W \:\per\:\person,
\]
if wind turbines were packed
% at the maximum possible density
across the {\em{whole}\/} country, and assuming 2\,\Wmm\ is the correct power
per unit area.
Converting to our favourite power units,
that's 200\,{kWh/{d} per person}.
%\beqa
% \mbox{maximum conceivable wind power}
%% \lefteqn{ \mbox{Maximum conceivable wind power (assuming 6\,\m/s)} \hspace{2in} }\\
%& \simeq & 200\,\mbox{kWh/{d} per person}.
%% was 210 , then 192...
%\eeqa
Let's be realistic.
% Can we really imagine completely covering the country with windmills?
What fraction of the country can
we really imagine covering with windmills?
% filling densely
Maybe 10\%?
% Taking 10\% of the maximum
% conceivable wind power,
%% (still assuming 6\,\m/s),
% we obtain%
%\beqa
%\lefteqn{ \mbox{maximum conceivable wind power (assuming 2\,\Wmm} }
%\\
% \mbox{in 10\% of the UK)}
% & = \:\: \OliveGreen{20\,\kWh/\d\ \mbox{per person}}.&
%% used to be 21.
%\eeqa
% Incidentally, the number of windmills of the Wellington size
% if this plan were implemented
%%% square of size 125m, i.e. 8x8 is 64 per sq km
%%% total area 244 000 sq km
% would be 300\,000.
%% pr 60e6 * 21.0 / 1400 / 3.0
%% 300000.0
%% pr 64 * 244000.0 * 0.1
%% 1561600.0
%
\amarginfig{c}{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}cc}
{\small\sc Consumption}& {\small\sc Production}\\
\multicolumn{2}{@{}c}{\mbox{\epsfbox{metapost/stacks.22}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Chapter \protect\ref{ch.wind}'s conclusion:
the maximum plausible production from on-shore windmills
in the United Kingdom is 20\,kWh per day per person.
}
}%
% \end{figure}
Then we conclude: if we covered the windiest
%% most productive
10\% of the country with
windmills (delivering 2\,\Wmm), we would be able to generate
\OliveGreen{20\,kWh/d per person}, which is
{\bf\em half\/}
of the power used by driving an average fossil-fuel car
50\,\km\ per day.
Britain's onshore wind energy resource may be ``huge,'' but it's evidently not
as huge as our huge consumption.
We'll come to offshore wind later.
% AMMO ***
%\section{How audacious an assumption I'm making}
I should emphasize how generous
% audacious
an assumption I'm making.
Let's compare this estimate of
British wind potential with current installed wind power
worldwide.\label{pWorldWind}
The windmills that would be
required to provide the UK with 20\,kWh/d per person
amount to 50 times the entire wind hardware of \ind{Denmark};
7 times all the {\windfarm}s of \ind{Germany};
and double the entire fleet of all wind turbines in the world.
% 50 times the Danish fleet;
% and seven times the German fleet.
%%% wwindea.org
%%% world capacity = 74GW at end of 2006. Germany has 20.6GW, Spain and USA both 11.6. Denmark 3.1
%%% capacity required to get 20 kWh/d is 50GW average ie 150 GW peak
%%% 150 is 7 times germany and 50 times Denmark
% http://www.energinet.dk/en/menu/Frontpage.htm#
% cool danish site has live export display
% [ 50kWh/d is 375 GW peak ]
%
% \begin{center}
%{\mbox{\epsfbox{crosspad/wind6.ps}}}
% \end{center}
Please don't misunderstand me. Am
I saying that we shouldn't bother building {\windfarm}s? Not at all.
I'm simply trying to convey a helpful fact, namely that if we want
wind power to truly make a difference, the {\windfarm}s must cover
a very large area.
%\section{Calculate it again}
This conclusion%
\margintab{\small
% \begin{figure}
\begin{center}
\begin{tabular}{cc} \toprule
\multicolumn{2}{l}{\sc\OliveGreen{Power per unit area}}\\ \midrule
\windfarm & \OliveGreen{2\,\Wmm}\\
(speed 6\,m/s) \\
\bottomrule
\end{tabular}
\end{center}
% }{
\caption[a]{Facts worth remembering: {\windfarm}s.
%% , number 1
}
}
% Mean wind speeds in Dundee (\figref{fig.dundee}) never passed 3\,m/s.
-- that the
maximum contribution of onshore wind,
% most that onshore wind could add up to,
albeit ``huge,'' is much less
than our consumption -- is important, so let's
check the key figure, the assumed
power per unit area of {\windfarm} (2\,W$\!$/m$^2$),
against a real UK {\windfarm}.
% estimate what wind could
% offer in a second way.
% Let's go a to a real
%% state-of-the-art
% windfarm and find out what it generates.
% Let's go back to cars and try to understand them better.
% Whitelee windfarm on Eaglesham moor near Glasgow
The \ind{Whitelee \windfarm}\index{wind farm!Whitelee} being built
near \ind{Glasgow} in Scotland
% (a windier place than average in the UK) to come on stream mid 2009
has 140 turbines with a combined
{\em peak\/} \ind{capacity} of 322\,MW in an area of 55\,km$^2$.
That's 6\,\Wmm,
% 5.85\,\Wmm,
{\em peak}. The average power produced is smaller
because the turbines don't run at peak output all the time.
The ratio of the average power to the peak power is called
the ``\ind{load factor}''
or ``\ind{capacity factor},'' and it
varies from site to site, and with the choice of hardware
plopped on the site; a typical
factor for a {{good}\/} site with modern turbines
is $30\%$.\nlabel{pCapFacNotREFd}
% this label is not refd but the same fact is refd in wind2.tex ***
If we assume Whitelee has a \ind{load factor} of 33\%
% --40 (since winds are stronger in Scotland)
then the average power production per unit land area is
\OliveGreen{2\,\Wmm} --
%% --2.3
exactly the same as the power per unit area we
assumed above.
% *** these tables are not referred to
%% BIFURCATION POINT old version is in __wind.tex
\amargintab{b}{\small
% \begin{figure}
\begin{center}
\begin{tabular}{c@{\,$\leftrightarrow$\,}c} \toprule
\multicolumn{2}{c}{\sc Population density }\\
\multicolumn{2}{c}{\sc of Britain }\\ \midrule
250 per km$^2$ & 4000\,\m$^2$ per person \\
\bottomrule
\end{tabular}
\end{center}
% }{
\caption[a]{Facts worth remembering: \ind{population density}.
See page \pageref{pDensities}
% and \pageref{countriesD}
for more population densities.\index{population density}
%% , number 1
}
}
% estimated assuming a typical wind speed of 6\,m/s.
\vfill
\pagebreak[4]%%newpageone
%% see _wind.tex for further notes
\section{Queries}
\qa{Wind turbines are getting bigger all the time.
Do bigger \ind{wind turbine}s change this chapter's answer?
}{
% Appendix
Chapter \ref{ch.wind2} explains.
Bigger wind turbines deliver financial \ind{economies of scale}\index{economics!of wind},
% -- a good idea,
% financially
but they don't greatly increase the total power per unit land area,
because bigger windmills have to be spaced further apart.
A \windfarm\ that's twice as tall will deliver roughly
30\% more power.
% pr 2.0**(3.0/7.0)
% 1.34590019263236
% 2**(1.0/7) = 1.1041
}
\qa{Wind power fluctuates all the time.
Surely that makes wind less useful?
}{
Maybe. We'll come back to this issue
in \chref{ch.storage}, where we'll look
at wind's intermittency and discuss
several possible solutions to this problem, including energy storage
and demand management.
}
\begin{figure}[tbp]
\figuremargin{
\begin{center}
\begin{tabular}{c@{ \ \ \ \ }c}
\mono%
{\epsfxsize=2.05in\epsfbox{../data/cambridge/mono/DailyHist.eps}}%
{\epsfxsize=2.05in\epsfbox{../data/cambridge/DailyHist.eps}}%
&
\mono%
{\epsfxsize=2.05in\epsfbox{../data/cambridge/mono/HalfHourlyHist.eps}}%
{\epsfxsize=2.05in\epsfbox{../data/cambridge/HalfHourlyHist.eps}}%
\\[14pt]
{\footnotesize speed (m/s)}&
{\footnotesize speed (m/s)}\\
\end{tabular}
\end{center}
}{
\caption[a]{Histogram of Cambridge\index{data!wind!Cambridge} average\index{windspeed!Cambridge}
wind speed in metres per second: daily averages (left),
and half-hourly averages (right).\index{wind!data}
%% Mean wind speed was 2.7 m/s
% DO I NEED TO SAY WHAT VERTICAL AXIS IS?
}
\label{fig.camb.wind2}\label{fig.windhisto}
}
\end{figure}
\beginfullpagewidth\small
\section{Notes and further reading}
\nopagebreak
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{fig.camb.wind}]
{\nqs{\Figref{fig.camb.wind} and \figref{fig.camb.wind2}}}.
Cambridge wind data
are from
the Digital Technology Group, Computer Laboratory, Cambridge
\protect\tinyurl{vxhhj}{http://www.cl.cam.ac.uk/research/dtg/weather/}.
The weather station is on the
roof of the Gates building, roughly 10\,m high.
Wind speeds at a height of 50\,m are usually about 25\% bigger.
Cairngorm data ({\nqs{\figref{fig.cairngorm}}})
are from\index{wind!data}
Heriot--Watt University Physics Department
\tinyurl{tdvml}{http://www.phy.hw.ac.uk/resrev/aws/awsarc.htm}.
\item[\npageref{pWorldWind}]
{\nqs{The windmills required to
provide the UK with 20\,kWh/d per person
are 50 times the entire wind power of \ind{Denmark}}}.
Assuming a load factor of 33\%, an average power of
20\,kWh/d per person requires an installed capacity of 150\,GW\@.
At the end of 2006, Denmark had an installed capacity of 3.1\,GW;
% new numbers at end of 2007 3.125
\ind{Germany} had 20.6\,GW\@.
% 22.247
The world total was 74\,GW
% 93.849
(\myurl{wwindea.org}).
Incidentally, the load factor of the Danish wind fleet was 22\% in 2006,
and the average power it delivered was 3\,kWh/d per person.
% 5,468,120 denmark population
% 3.1GW ~=
% http://www.windpower.org/composite-1463.htm
%% In 2006, the turbines in Denmark produced 6,108 GWh.
% that is 0.697 GW That is 22.49% load factor
% [16.8 percentage of the electricity consumption in Denmark]
% per person, it's 6108e6 / 365 / 5468120
% 3.0603 kWh/d/p
\end{notelist}
\ENDfullpagewidth
\normalsize
%% http://news.bbc.co.uk/1/hi/uk/6969865.stm
%% Costing the Earth
\rset\chapter{\rcol{Planes}}%Air travel}
\label{ch.air}
\label{ch.planes}
\marginfignocaption{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/747/747FrontSideD.jpgS.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/747/747FrontSideD.jpg.eps}}}\\
\end{tabular}
\end{center}
%\caption[a]{
% A \ind{Boeing 747}\index{747}, yesterday.
% }
}
%% Typical Fuel Burn (on 3,450 statute-mile flight) (cf range 8430 miles)
%% 56,700kg.
%% 300lb or 409lb per passenger, depending on 747-400 or 747-100
%% (400 better because more passengers: 416 versus 366)
%% that's 136 kg per passenger; which at 46MJ/kg is
%% 1739 kWh one way, or 9.5 kWh per day for a round trip
%% from
%% http://gocalipso.com/aircraft/boeing747/spec.php
Imagine that you make one intercontinental trip per year by \ind{plane}.
How much energy does that cost?
% Let's get a quick estimate first; then,
% as with our investigation of
% cars, we'll visit this question with more careful
% attention, so as better to understand the cost of \ind{air travel}.
% A 747-400 that flies 3,500 statute miles (5,630 km) and carries 126,000 pounds (56,700 kg) of fuel will consume an average of five gallons (19 L) per mile.
%%% fun facts (url not needed)
%% http://www.boeing.com/commercial/747family/pf/pf_facts.html
A Boeing\label{Boeing} 747-400 with $240\,000$\,litres
of fuel carries 416
%% 216,847l is 57285 US gal
%% LA is 9000km.
%% cape town is 9671 km.
passengers about $8\,800$ miles ($14\,200\,\km$).
And fuel's calorific value is 10\,\kWh\ per litre. (We learned
that
%from
% remember the
% \margarine\
in \chref{ch.car}.)
So the energy cost of one full-distance
round-trip on such a plane, if divided equally among the passengers,
is
\[%beq
\frac{ 2 \times 240\,000\, \litre }{ 416\, \mbox{passengers} }
\times 10\,\kWh / \litre
\simeq 12\,000 \,\kWh \ \mbox{per passenger} .
\]%eeq 12058.
% using 10.4 from cars.tex
If you make one such trip per year, then
your average energy consumption per day is
\[%beq
\frac{ 12\,000 \,\kWh }
{ 365 \, \udays }
\simeq 33 \,\kWh/\uday .
\]%eeq
14\,200\,km is a little further than London to Cape Town (10\,000\,km)
%%% New York to London, England is 3471 miles (5585 km)
and London to Los Angeles (9000\,km), so I think we've slightly
overestimated
the distance of a typical long-range intercontinental trip; but
we've also overestimated the fullness of the plane, and
the energy cost per person is more if the plane's not full.
Scaling down by 10\,000\,km/14\,200\,km to get an estimate for Cape Town,
then up again by 100/80 to allow for the plane's being 80\% full, we arrive at
{{29\,kWh per day}}.
% 2*240000/416 * 10.4 /365.25 *10000/14200 * 100/80 = 28.921
For ease of memorization, I'll round this up to
{\Red{30\,kWh per day}}.
Let's make clear what this means.
Flying once per year has an energy cost slightly bigger than
leaving a 1\,kW electric fire on, non-stop,
24 hours a day, all year.
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{cc}
%{\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.23}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{
% Chapter \protect\ref{ch.air}'s conclusion:
Taking one intercontinental trip
% and two short-haul trips per year
% uses about 35\,kWh per day. (29 for the intercontinental trip, and
% at least 6 for the short-haul trips.
per year uses about 30\,kWh per day.
}
}
Just as \chref{ch.car}, in which we estimated consumption by cars,
%% invalid carriages,
was accompanied by \appref{ch.car2}, offering a model of where the energy
goes in cars,
%% invalid carriages,
this chapter's technical partner (\appref{ch.air2}, \pref{ch.air2}),
discusses where the energy goes in planes.
%%%% This discussion may interest you, because
% You'll be able to answer the question
% `if I take 30\,\kg\ less luggage with me on my trip,
% does that make any difference to the energy consumed by the
% plane?'
%
\Appref{ch.air2}
% This discussion
allows us to answer questions such as
``would air travel consume significantly less energy if
we travelled in slower planes?''
The answer is {\bf no}: in contrast to
wheeled vehicles, which {\em{can}\/} get more efficient the
slower they go, planes are
already almost as energy-efficient as they could possibly be.
Planes unavoidably have to use energy for two reasons:
they have to throw air down in order to stay up,
and they need energy to overcome air resistance.
No redesign of a plane is going to radically improve
its efficiency. A 10\% improvement? Yes, possible.\label{pRolls} A doubling
of efficiency? I'd eat my complimentary socks.
\section{Queries}
\beforeqa
\qa{Aren't \ind{turboprop} aircraft\index{plane!turboprop}\index{aircraft!turboprop}
{\em far\/} more energy-efficient?\label{pTurboprop}
}{
No. The ``comfortably greener'' \ind{Bombardier Q400} NextGen,
``the most technologically advanced turboprop in the world,''%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ph_bombardier_q400_07S.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ph_bombardier_q400_07.jpg.eps}}}%
\end{tabular}
\end{center}
\caption[a]{Bombardier Q400 NextGen.
% Photograph from
\myurl{www.q400.com}.
}
}
according to its manufacturers [\myurl{www.q400.com}],
uses 3.81 litres per 100 passenger-km (at a cruise speed of 667\,km/h),
which is an energy cost of \eccol{38\,kWh per 100\,p-km}.
% cruise speed 667 km/h
The full 747 has an energy cost of \eccol{42\,kWh per 100\,p-km}.
So both planes are twice as fuel-efficient as a single-occupancy car.
(The car I'm assuming here is the average European car that we discussed
in \chref{ch.cars}.)
%\begin{table}
% \figuremargin{
\margintab{
\begin{tabular}{ll}\toprule
\multicolumn{2}{r}{{energy per distance}}\\
\multicolumn{2}{r}{{(kWh per 100\,p-km) }} \\ \midrule
Car (4 occupants) & 20 \\
% Boeing 777 & 23 \\ % about 1 MJ per skm would be 27 ?
Ryanair's planes,\\
\ \ year 2007 & 37 \\ % corrected Sat 15/12/07
Bombardier Q400, full & 38 \\ % added Wed 6/8/08
747, full & 42 \\% corrected Sat 15/12/07
747, 80\% full & 53 \\% corrected Sat 15/12/07
Ryanair's planes,\\
\ \ year 2000 & 73 \\ % corrected Sat 15/12/07
Car (1 occupant) & 80 \\% corrected Sat 15/12/07
\bottomrule
\end{tabular}
% }{
\caption[a]{
Passenger transport efficiencies, expressed
as energy required per 100 passenger-km.
%% unit of transport.
%% 33 miles per imperial gallon is
%% 12\,km\ \per\ \litre.%%% 11.68
%% The SAX-40 design mission is to carry 215 passengers for 5000 nm.
%% assume payload is 240 lb per passenger.
}
}
%\end{table}
}
\qa{Is flying extra-bad for climate change in some way?}{
Yes, that's the experts' view, though uncertainty remains
about this topic
% (See
\tinyurl{3fbufz}{http://www.ipcc.ch/ipccreports/sres/aviation/004.htm}.
Flying creates
other greenhouse gases in addition to \COO, such as \ind{water}
and \ind{ozone},
and indirect greenhouse gases, such as \ind{nitrous oxides}.\index{flight!emissions}
If you want to estimate your
carbon footprint in \tonnes\ of \COO-equivalent, then you should
take the actual \COO\ emissions of your flights and bump them
up two- or three-fold.
% The precise factor depends on whether the flight is daytime or nighttime.
This book's diagrams don't include that multiplier because
here we are focusing on our {\em{energy}\/} balance sheet.
}
% \end{figure}
% no significant gains
% in the efficiency of planes are possible.]
% \section{Queries}
\myquote{The best thing we can do with environmentalists is shoot them.}%
{\index{O'Leary, Michael}{Michael O'Leary}, CEO of \ind{Ryanair}
\tinyurl{3asmgy}{http://news.independent.co.uk/uk/transport/article324294.ece}
}
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{Boeing}] {\nqs{Boeing 747-400}} --
data are from\index{transport!efficiency!plane}
\tinyurl{9ehws}{http://www.boeing.com/commercial/747family/technical.html}.
% Incidentally, using these figures we can obtain the
% \ind{fuel efficiency} of the completely-full 747.
%% pr (240000 * 10.45 ) / (416 * 142 )
% It works out to 42\,kWh per 100 passenger-km --
Planes today are not completely full.\index{fuel efficiency, plane}
Airlines are proud if their average
fullness is 80\%.
Easyjet planes are 85\% full on average.
(Source: {\tt{thelondonpaper}} Tuesday 16th January, 2007.)
% \tinyurl{2blc2w}{http://www.feedsfarm.com/article/ca2f7598ebd154927dada9e3b5bd81aaadeec28b.html}
An 80\%-full 747 uses about 53\,kWh per 100 passenger-km.
% See flight.tex for easyjet fact.
% Load factor of Easyjet up to 90\%.
% BBC News, Monday, 7 August 2006.
% \tinyurl{2oatgv}{http://news.bbc.co.uk/2/hi/business/5251546.stm}
% If we make our one intercontinental round-trip flight per year on
% an 80\%--full plane,
% this chapter's 30\,\kWh/d
% is bumped up to 35\,kWh/d. CORRECTED Sat 15/12/07
%EasyJet's current operations generate 97.5 grams of CO2 per passenger kilometer
%
% there is a sweet spot for a 747 at range of 6000 km when it can
% deliver 1.7 MJ/skm
%\qa
{What about short-haul flights?
}
%%% TODO
% Put numbers here, and express London--Rome in kWh/d too.
%% The \ind{737} burns approx 30\,kg per minute.
%% http://www.b737.org.uk/rulesofthumb.htm
%% An A300 with 270 pax needs about 5.000 kg for a 500 km sector.
%% For what its worth, a B757 with a (full) ZFW of 80000kg
%% will require about 7000kg on a 2 hour short sector, about 11000 on 3 hours.
%% http://www.pprune.org/forums/showthread.php?t=235790
In 2007, \ind{Ryanair}, ``Europe's greenest airline,''
delivered transportation at a cost of
% 3.5\,litres per 100 passenger-km (
\eccol{37\,kWh per 100\,p-km}
% 36.575
\tinyurl{3exmgv}{http://www.ryanair.com/site/EN/about.php?page=About&sec=environment}.
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/RyanairarpS.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Ryanairarp.eps}}}%
\end{tabular}
\end{center}
\caption[a]{Ryanair Boeing 737-800. Photograph by Adrian Pingstone.
% Ryanair Boeing 737-800 (registration EI-DCK) taking off from Bristol International Airport, Bristol, England.
% Photographed by Adrian Pingstone in December 2006 and released to the public domain.
}
}%
This means that flying across Europe with Ryanair has much the same
energy cost as having all the passengers drive to their destination
in cars, two to a car.
(For an indication of what other airlines might be delivering,
Ryanair's fuel burn rate in 2000, before their
environment-friendly investments,
was above
% 7\,litres per 100 passenger-km (
\eccol{73\,kWh per 100\,p-km}.)
% fixed Sat 15/12/07
%
London to Rome is 1430\,km; London to Malaga is 1735\,km.
So a round-trip to Rome with the greenest airline
has an energy cost of 1050\,kWh,
and a round-trip to Malaga
costs 1270\,kWh. If you pop over to Rome and to Malaga once per year,
your average power consumption is 6.3\,kWh/d with the greenest
airline, and perhaps 12\,kWh/d with a less green one.
% this or 2.4\,kWh/d if you make one trip per year;, or 3\,kWh/d.
% The decision to take one round-trip to Rome with the greenest airline
% is the same, in energy terms, as leaving a 1\,kW electric fire
% on for five weeks.
%\qa
{What about frequent flyers?}
{To get a silver frequent flyer card from an intercontinental
airline, it seems
% with Virgin Atlantic,
one must fly around 25\,000 miles per year in economy class.
% BA: each tier point is about 100 miles virgin require 15 tier points
% to move up , and a tier point is about 3000 miles.
% No, for new york, 7000 miles round trip gets you 4 tier
% points.
% pr 25000/8800.0 * 240000.0 / 416.0 * 10.45 / 365.25 / 0.8
That's about 60\,kWh per day, if we scale up the opening
numbers from this chapter and assume planes are 80\% full.
}
Here are some additional figures from the Intergovernmental Panel
on Climate Change\index{IPCC}
\tinyurl{yrnmum}{http://www.grida.no/climate/ipcc/aviation/124.htm}:
% 383 seats is standard in australia
a full 747-400 travelling 10\,000\,km with low-density seating (262 seats)
has an energy consumption of
% 1.8 MJ/seat km
\eccol{50\,kWh per 100\,p-km}.
In a high-density seating configuration (568 seats) and travelling
4000\,km, the same
plane has an energy consumption of
% 0.8 MJ/skm
\eccol{22\,kWh per 100\,p-km}.
A short-haul Tupolev-154 travelling 2235\,km with 70\%
of its 164 seats occupied consumes
% 2.9 MJ/pkm
\eccol{80\,kWh per 100\,p-km}.
% overall intensity of air travel, allowing for load factors:
% LINDEN 1999 says 1.75MJ of secondary energy per pkm
% which is 47kWh/100pkm for MODERN aircraft
% (ie excluding energy cost of extraction and refining and
% t ransport)
% BA and lufthansa say 56 and 52 kWh/100p-km
% Each take off and landing cycle increases
% consumption by 1000 MJ/passenger (280 kWh)
% standard CO2 factor for kerosene: 69g per MJ
% which is 248 g per kWh
% from http://www.channelviewpublications.net/jost/010/0114/jost0100114.pdf
% If you go to New Zealand and back then 40,000 km round trip, 20,000 km one way
% Jet fuel costs about 130$ per barrel
% 737-400 burns fuel at a rate of 2450 kg per hour
% 747-400 burns fuel at a rate of 10,000 kg per hour
% A 737-400 burns 825 kg per landing-takeoff
% A 747-400 burns 3400 kg per landing-takeoff
% from http://www.casa.gov.au/oar/download/EconomicValues.pdf
% 149 seats in a 737-400
\item[\npageref{pRolls}]
{\nqs{No redesign\index{efficiency!more-efficient planes}\index{plane!efficiency improvements}
of a plane is going to radically improve
its efficiency}.}
Actually, the
Advisory Council for Aerospace Research in Europe
(ACARE)\label{pPlaneTargets}
target is for an overall 50\% reduction in fuel
burned per passenger-km by 2020 (relative to a 2000 baseline), with
15--20\% improvement expected in engine efficiency.
As of 2006, \ind{Rolls Royce} is half way to this engine target
\tinyurl{36w5gz}{http://www.rolls-royce.com/community/downloads/environment04/products/air.html}.%
\marginfig{
\begin{center}
\begin{tabular}{c}
{\mbox{\epsfbox{metapost/stacks.303}} }\\
\end{tabular}
\end{center}
\caption[a]{Two short-haul trips \newlineone
on the greenest
short-haul airline: 6.3\,kWh/d. Flying enough to
qualify for silver frequent flyer status: 60\,kWh/d.}
}
Dennis Bushnell, chief scientist at
NASA's Langley Research Center, seems to agree with
my overall assessment of prospects for
efficiency improvements in aviation. The aviation industry
is mature. ``There is not much left to gain
except by the glacial accretion of a per cent here and
there over long time periods.'' (New Scientist, 24 February 2007, page 33.)
% I removed the word SAX-40 to prevent ORB
The radically reshaped ``Silent Aircraft''\index{SAX-40}\index{silent aircraft}
[\myurlb{silentaircraft.org/sax40}{http://silentaircraft.org/sax40/}], if it were built,
is predicted to be 16\% more efficient than a conventional-shaped plane
% page 52
% SAX site says (I translated)
% (19\,kWh per 100\,pkm, compared with 23\,kWh per 100\,pkm for the Boeing 777)
\citep{Nickol}.
%\myurl{http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080012497_2008011089.pdf}
If the ACARE target is reached, it's presumably going to be
thanks mostly to having fuller planes and better air-traffic management.
\end{notelist}
\normalsize
% > The SAX-40 (Cambridge-MIT) guesses 20-45 % fuel reduction.
% 149 passenger-miles per UK gallon of fuel (compared with about 121 for the best current aircraft in this range and size).
% http://silentaircraft.org/sax40/
% (10 (kWh per litre)) / (149 (miles per Imperial gallon)) = 0.189584599 kWh per km
% 19kWh/100km compared with 23.3kWh for the best current aircraft
% Boeing 777 does 103-121 pmiles per UK gal.
% That is 23.3-27.4 kWh per 100pkm
%% Propeller-driven planes achieve massive fuel benefits on shorter journeys,'' Kapil Kaul, of the Centre for Asia Pacific Aviation, said.
%%For a trip of less than 600 nautical miles, or about 90 minutes' flying time, a turboprob may use as much as 70 per cent less fuel than a similar-sized jet, he said.
%% http://business.timesonline.co.uk/tol/business/industry_sectors/transport/article3745007.ece
%% Bombardier Q400, one of the most advanced turboprops
%% http://www.q400.com/q400/en/home.jsp
%% ``the turboprop airliner for the twenty-first century''
%% 360 kt cruise speed
%% 300 nm trip: 5 US gallons per seat
%% 74 seats
%% max cruise power 3947 shp
%% baggaeg volume 14m3
%% max landing weight 28t.
%% max payload 8.7t
%% fuel capacity 6526l.
%% range, 70 passengers, 2522km
%% max cruise speed 667 km/h
%% 3.81 litres per 100 p-km
%% 74 passengers, sharing out 210l per 100km
%% 38 kWh per 100 p-km
\gset\chapter{\gcol{Solar}}
\label{chsolar}
\label{ch.solar}
We are estimating how our consumption stacks up against
conceivable sustainable production.
In the last three chapters we found car-driving
and plane-flying to be bigger than the plausible on-shore wind-power
potential of the United Kingdom.
Could \inds{solar power} put production back in the lead?
%As I've said before, we will focus attention on the {\bf{capacity}}
%of solar power, not its cost. The cost of solar is
%important, of course; but I'm focussing on how much solar energy there is.
% , even if solar panels could be made for free.
% \begin{figure}[htbp]
% \figuremargin{
\marginfig{
%\begin{center}
\begin{tabular}{@{}l@{}}
\mbox{\epsfbox{metapost/earth.15}}%crosspad/solar1.ps}}\epsfysize=35mm
\\
\end{tabular}
%\end{center}
%}{
% COLON
\caption[a]{%Left:
Sunlight hitting the earth at midday on a
spring or autumn day.
The density of sunlight per unit land area in Cambridge
(latitude $52\degrees$) is about 60\% of that at the \ind{equator}.
}\label{fig.equatCam}
}
%\end{figure}
The power\index{power density!sunshine} of raw \ind{sunshine} at midday on a cloudless day
is $1000\,\W$ per square metre.\index{power!of sunshine}\index{flux, sunlight}
% $\m^2$.
That's
$1000\,\W$ per $\m^2$
of area
oriented towards the sun,
not per $\m^2$
of land area.
To get the power per $\m^2$
of {\em land area} in Britain,
we must make several \MidnightBlue{corrections}.
We need to compensate for the tilt between the sun and the land, which
reduces the intensity of midday sun to
about \MidnightBlue{60\%} of its value at the equator
(\figref{fig.equatCam}).\nlabel{latitude}
% I'll call this the {\dem\ind{latitude factor}}.
% \begin{figure}
% \figuremargin{
We also lose out because it is not midday all
the time.
% It's a fair approximation to say that it's midday
% about $1/4$ of the time, and dark the other $3/4$.
% So we have a {\dem\ind{daylight factor}\/} of $1/4$.
% The {\dem\ind{daylight factor}\/} in March and September --
On a cloud-free day in March or September,
the ratio
of the {\em average\/} intensity to the midday intensity
is about \MidnightBlue{32\%}.
% [The area of sunlight intercepted by the earth
% is $\pi R^2$, and the surface area of the earth
% is $4 \pi R^2$.]
%% [The mean of [H is threshold] H(sin(t) ) is 0.31 ]
%
Finally, we lose power because of \ind{cloud cover}.
In a typical \UK\ location the sun shines
during just \MidnightBlue{34\%} of daylight hours.\nlabel{sunniness}
% we should include a {\dem\ind{sunniness factor}\/}
% of 0.34.\nlabel{sunniness}
% the sun shines perhaps one third of the time.
%
% pr cos(pi/2.0 * 52.0/90.0)
% 0.615661475325658
% pr cos(pi/2.0 * 52.2/90.0)
% 0.61
\marginfig{
\begin{center}
\begin{tabular}{@{}c}
\mbox{\epsfxsize=52mm%
{\epsfbox{../data/NASA.eps}}%
}
\\
\end{tabular}
\end{center}
% }{
\caption[a]{Average solar intensity
in London and Edinburgh
as a function of time of year.
The average intensity, per unit land area,
is 100\,\Wmm.\index{data!sunniness}\index{sunniness}
}
\label{fig.NASAsun}
}
The combined effect of these three factors and the additional
complication of the wobble of the seasons is that
the average raw power of sunshine per square metre
of south-facing roof in Britain is roughly 110\,\Wmm,
% see NASA.gnu
and the average raw power of sunshine per square metre
of flat ground is
roughly 100\,\Wmm.\nlabel{p100W}
% mean on solar panel facing at 54 deg: 2.4667 kWh/mm/d
% or at zero deg: 2.5 kWh/mm/d
% http://eosweb.larc.nasa.gov/cgi-bin/sse/grid.cgi?email=mackay%40mrao.cam.ac.uk&step=2&lat=54&lon=-4&num=177145&p=grid_id&p=swvdwncook&p=avg_dnr&p=ret_tlt0&p=day_cld&veg=17&hgt=+100&submit=Submit
% (100\,\Wmm\ sounds surprisingly
% large compared with the south-facing
% roof's 110\,\Wmm, but it is correct.)
We can turn this raw power into useful power in four ways:
\ben
\item
Solar thermal:\index{thermal, solar} using the sunshine for direct heating of buildings
or water.
\item
Solar \ind{photovoltaic}: generating electricity.
\item
Solar \ind{biomass}: using trees, bacteria, algae,
corn, soy beans, or oilseed to make energy fuels, chemicals, or building materials.
\item
Food:\index{food} the same as solar biomass, except we shovel
the plants into humans or other animals.
\een
(In a later chapter we'll also visit
a couple of other solar power techniques appropriate for use in deserts.)
%% CSP and thermal chimneys
Let's make quick rough estimates of the maximum plausible powers that
each of
these routes could deliver. We'll neglect their economic costs, and the
energy costs of manufacturing and maintaining the power facilities.
% http://www.viridiansolar.co.uk/Technology%203%20The%20Efficiency%20of%20Solar%20Panels.htm
% shows ``Advanced flat plate''
% 50% working efficiency when temp diff is 70 degrees above
% outside
\section{Solar thermal}
%\marginfig{
\begin{figure}
\figuremargin{
\begin{center}
\begin{tabular}{@{}cc@{}}
{\epsfxsize=59mm\epsfbox{../data/viridian.eps}}
&
\raisebox{1.5mm}{\epsfxsize=39mm\epsfbox{../../images/viridian.eps}}
\\
\end{tabular}
\end{center}
}{
\caption[a]{Solar power generated by a 3\,m$^2$
hot-water panel (green), and supplementary
heat required (blue) to make hot water
in the test house
of \ind{Viridian Solar}.
(The photograph shows a house with the same model of panel
on its roof.)
The average solar power from 3\,m$^2$ was \OliveGreen{3.8\,kWh/d}.
The experiment simulated the hot-water consumption
of an average European household -- 100 litres of
hot (60\degreesC) water per day.
% The green region shows the
% solar power generated, peaking at 6\,kWh/d
% in the Summer; t
The 1.5--2\,kWh/d gap between the total heat generated (black line, top)
% roughly 7\,kWh/d)
and the hot water used (red line)
is caused by heat-loss.
% from the hot water system.
The magenta line shows the electrical power required to
run the solar system.
The average power per unit area\index{power density!hot water panels}
of these solar panels is \OliveGreen{53\,\Wmm}.
}\label{viridian}
}%
\end{figure}
The simplest solar power technology is a panel making
hot water.
Let's imagine we cover {\em{all}\/}
south-facing roofs with solar thermal panels --
%
% a sensible assumption would be that half of domestic demand
% is met by 4m**2 of collectors (presumably for 2.5 people).
% And that half of hot water in offices would be covered too.
% xpdf EnglishPartnerships2003.pdf
%
that would be about
10\,m$^2$ of panels per person\nlabel{areaBuildings} -- and let's assume these are
50\%-efficient at
turning the sunlight's $110\, \Wmm$ into hot water (\figref{viridian}).\nlabel{p50solar}
%% this pointer no longer needed
Multiplying
\[
50\% \times 10\,\m^2 \times 110 \,\Wmm
% \times 24 \,\mbox{hours/day}
\]
we find \ind{solar heating} could deliver
\[
\OliveGreen{13\,\kWh \,\, \mbox{per day per person}}.
\]% 13.2
I colour this production box white in \figref{fig.thermalHW} to indicate
\amarginfig{t}{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}cc}
%{\small\sc Consumption}& {\small\sc Production}\\
\multicolumn{2}{@{}c}{\mbox{\epsfbox{metapost/stacks.24}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Solar thermal:
a 10\,m$^2$ array of thermal panels can deliver
(on average) about 13\,\kWh\ per day of thermal energy.
}\label{fig.thermalHW}
}%
% \end{figure}
that it describes production of \ind{low-grade energy}\index{energy!low-grade} --
hot water is
not as valuable as the high-grade electrical energy that
wind turbines produce. Heat can't be exported to the electricity grid.
If you don't need it,
% if it's too much,
then it's wasted.
We should bear in mind that much of this captured heat would
not be in the right place. In cities, where many people live,
residential accommodation has less roof area per person
than the national average. Furthermore, this power would be
delivered non-uniformly through the year.
% See ocean.tex for power density table.
% \input{solarth.tex}
\section{Solar photovoltaic}
Photovoltaic (PV) panels convert sunlight into electricity.
Typical solar panels have an efficiency of about 10\%;
expensive ones perform at 20\%.\nlabel{pv20}\index{photovoltaic}\index{solar photovoltaics}
(Fundamental physical laws limit the efficiency of
photovoltaic systems to at best 60\% with perfect concentrating mirrors
or lenses, and 45\% without concentration.
A mass-produced device with
efficiency greater than 30\% would be quite remarkable.\nlabel{pHopf})
% pr 0.94*0.85*0.75
% 0.59925
% gnuplot> pr 0.94*0.85*0.75 *0.75
% 0.4494375
The average power delivered by south-facing 20\%-efficient photovoltaic panels
in Britain would be\nlabel{pMythPV}
\[
20\% \times 110\,\Wmm = \pdcol{22\,\Wmm}.
\]
\Figref{fig.girton} shows data to back up this number.
Let's give every person $10\,\m^2$ of expensive (20\%-efficient) \ind{solar panels}
and cover all south-facing roofs.
These will deliver
% one fifth of the incoming energy,
% of the solar--thermal panels,
% namely
\[
\OliveGreen{5\,\kWh \,\, \mbox{per day per person}}.
\]
Since the area of all south-facing roofs is 10\,m$^2$
per person,
there certainly isn't space on our roofs for
these
% \end{figure}
% The girton chap gets 30kWh/day on a really sunny blue day in May 2006.
% That is from a 25 m**2 array, IIRC
photovoltaic panels as well as the
solar thermal panels of the last section.
So we have to choose whether to have the photovoltaic contribution
or the solar hot water contribution.%
\amarginfig{t}{
% \begin{figure}
% method: solar.gnu2
\begin{center}
\begin{tabular}{@{}c}
\mbox{\epsfxsize=53mm\epsfbox{../../girton/solarMR.eps}} \\% was solarM
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../girton/PanelsSmall.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../girton/PanelsMed.jpg.eps}}} \\
\end{tabular}
\end{center}
% }{
\caption[a]{Solar photovoltaics:\index{data!photovoltaics}
data from a 25-m$^2$ array in Cambridgeshire in 2006.
The peak power delivered by this array is about 4\,kW\@.
% ie efficiency 4 / 25 = 16%.
% On the best summer days, the panels deliver 30\,kWh/day.
The average, year-round, is 12\,kWh per day.
%% 3.7kW for one hour (1831+1883 Wh per hour) in June or July
That's \OliveGreen{20\,W per square metre of panel}.
}
\label{fig.girton}
}
But I'll just plop both these
on the production stack anyway.
% -- or, best of all,
% buy integrated photovoltaic/hot-water panels.
% A solar-panel company said that 7.5 square metres
% was the most they could fit on my 3-bedroom house.
% 6 panels each 1.25 m**2
% We should remember that this is high-grade energy: electricity.
Incidentally, the present
cost of installing such photovoltaic panels is about four times
the cost of installing solar thermal panels, but they
deliver only half as much energy, albeit
high-grade energy (electricity).
So I'd advise a family thinking of going solar to
investigate the solar thermal option first. The smartest solution,
at least in sunny countries, is to make combined systems that
deliver both electricity and hot water from a single installation.
This is the approach pioneered by \ind{Heliodynamics}\nlabel{pHelio},
who reduce the
overall cost of their systems by surrounding small
% expensive
high-grade \ind{gallium arsenide} photovoltaic units with
arrays of slowly-moving flat
\ind{mirror}s; the mirrors focus\index{concentrating solar power}
the sunlight onto the photovoltaic units, which deliver both
electricity and hot water;\index{solar power!concentrating}
the hot water is generated by pumping water past the back
of the photovoltaic units.
The conclusion so far:
covering your south-facing roof at home with photovoltaics may
provide enough juice to cover quite a big chunk of
your personal average electricity consumption; but
% it doesn't look like
roofs are not big enough to make a huge dent in
our total {\em{energy}\/} consumption. To do more with PV, we need to
step down to terra firma. The solar warriors in
\figref{fig.adelman} show the way.
% \marginfig{
\begin{figure}[hbtp]
\figuremarginb{
\begin{center}
\begin{tabular}{c}
{\epsfxsize=110mm\epsfbox{../../images/adelmans.eps}} \\
\end{tabular}
\end{center}
}{
\caption[a]{Two solar warriors
enjoying their photovoltaic system, which powers their electric cars and home.
% 36.7kW DC
The array of 120 panels (300\,W each, 2.2\,m$^2$ each) has an area of 268\,m$^2$,
% 36.7kW DC
% (120 rectangles, each 2.2\,m$^2$),
a peak output (allowing for losses in DC--to--AC conversion) of 30.5\,kW,
and an average output -- in California, near Santa Cruz
-- of 5\,kW (\OliveGreen{19\,\Wmm}).
% Kenneth and Gabrielle Adelman's huge backyard system in Corralitos, California
Photo kindly provided by Kenneth
% and Gabrielle
Adelman.\index{Adelman, Kenneth}\index{solar warrior}
{\myurl{www.solarwarrior.com}}
% The Adelmans' photovoltaic system in California. Has a 2,880 square foot array with a theoretical output of 30.5kW. That is 268 sq m. peak output 0.11 kW/m**2
% http://www.solarwarrior.com/ pv-array-and-house.jpg adelmans.jpg adelmans-medium.jpg
% production during 2007 (whole year)
% found by requesting graph by hour from 8am: 4000W, 8000W, 12400, 16000,17000,17000,16500,13500,10000,6000,2000 (at 18hrs)
% ok, I get 122kWh per day, taking average production which is same as 5.1kW
% ask for 2006 as well:
% 4,8,11,14,16.5,16.3,15.6,13,9.5.5,2 In 2006 is produced 115 which means 17.9 W/mm
}
\label{fig.adelman}
}
\end{figure}
\subsection{Fantasy time: solar farming}
If a breakthrough of solar technology\index{solar farm}
occurs\nlabel{pSolarfarming} and the cost of photovoltaics
came down enough that we could deploy panels all over the countryside,
what is the maximum conceivable production?
Well, if we covered 5\% of the UK with 10\%-efficient panels,
we'd have
\beqa
&10\% \times
100\,\Wmm \times 200\,\m^2\:\mbox{per person}
% \times \mbox{24 hours per day}
&\\
\simeq&
\OliveGreen{50\,\kWh/\uday/\person} .
\eeqa
% 0.05 * 400 * 24 * 0.1
I assumed only 10\%-efficient panels, by the way, because
I imagine that solar panels would be mass-produced
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}c}
\lowres{\epsfxsize=53mm\epsfbox{../../images/BavariaSolar2S.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/BavariaSolar2.eps}} \\
\end{tabular}
\end{center}
% }{
\caption[a]{A solar photovoltaic farm:\nlabel{pBavaria}
the 6.3\,MW (peak) \ind{Solarpark} in
\index{Muhlhausen@M\"uhlhausen}{M\"uhlhausen}, \ind{Bavaria}.
% $0.50 per kWh guaranteed
% part of it cost 4 million euro including tracking of sun
% The whole facility at this site cost 31 million euro expect to last 20 y?
% cost per kWh: 31e6 / ( 20 * 365.25 * 17e3 )
% ans = 0.25 euro
% 57,600 solar modules with 175 Wp each capacity '3000 households'
% income of $8000 per day???
Its average power per unit land area is expected to be about \pdcol{5\,\Wmm}.
Photo by SunPower.
}
\label{fig.bavaria}
}on such a scale only if they were very cheap, and it's the lower-efficiency
panels that will get cheap first.
The \ind{power density} (the power per unit area) of such a solar farm would be
\[
10\% \times 100\,\Wmm = \pdcol{10\,\Wmm}.
\]
This power density is twice that of the Bavaria
Solarpark (\figref{fig.bavaria}).
% Portugal
% Number of photovoltaic panels 376 632
%Area occupied by power station 130 ha
%Installed rated power 62 MWp
%Annual electricity generation 88 GWh
%Power transformers 22
%Inverters 214
%CO2 avoided 60 000 t per year
%Investment EUR 250 million
% 10MW average -- 7.7 Wmm ok, presumably a sunnier location
% cost 250 million euro 4 euro per watt peak 25 euro per watt average
%source http://www.min-economia.pt/document/Energias_Renov_PT.pdf
Could this flood of
solar panels co-exist with the army of windmills we imagined in
\chref{ch.wind}? Yes, no problem: windmills cast little shadow,
and ground-level solar panels have negligible effect on the wind.
How audacious is this plan? The solar power capacity required to
deliver\index{solar photovoltaics!world total}
this 50\,kWh per day per person in the UK is more than 100 times
all the photovoltaics in the whole \index{world solar power}world.\nlabel{worldPV}
% end of 2007, 10GW peak world. and build rate roughly 2GW per year
% this plan requires 125GW average production, which (at 10% load factor)
% requires 1250GW peak.
So
should I include the PV farm in my sustainable production stack?
I'm in two minds. At the start of this book I said I
wanted to explore what the laws of physics say about the limits of
sustainable energy, assuming money is no object. On those grounds, I
should certainly go ahead, industrialize the countryside, and push the
PV farm onto the stack.
At the same time, I want to
% make helpful comments for today's society, to
help people figure out what
we should be doing between {\em{now}\/} and 2050.
And today, electricity from solar farms would be
four times as expensive as the market rate.
% 190 pounds rather than 45 pounds per MWh
% equivalent CO2 cost: 400 pounds per tonne of CO2
So
% Maybe in a future edition of this book I'll include the PV farm in
% my sustainable production stack, but today
% I feel
I feel a bit irresponsible as I include this estimate in
% cost to get 17 kWh/d/p:
% 31\,000 euro
% cost to get 50 kWh/d/p: 91\,000 euro per person see solarnotes for more
the sustainable production stack in \figref{fig.stack25} --
% I relegate this estimate to the land of pipe-dreams.
% I can imagine solar panels on every building,
% but
paving 5\% of the UK with solar panels
seems beyond the bounds of plausibility in so many ways.\nlabel{pPVfarmImplaus}
% Perhaps as a compromise I could include a smaller amount corresponding to
% an area equal to all roads (60\,m$^2$ per person)?
% seems implausible
% need to include land price too?
% http://statistics.defra.gov.uk/esg/index/list.asp?i_id=034
% North East: 8620 pounds per ha
% North West: 6294
% all england 7654 in 2004.
% divided by grade of land: 1,2: 7256; 4,5: 6572 Not much diff! LAND ONLY 6213 per ha.
% so to buy the bavaria 25 ha would cost just 190,000 pounds.
% ok - the land is not a big cost.
% One ray of hope:
% in sunnier countries, perhaps \index{solar!farm}{solar farm}s would be feasible.
% We'll return to this idea in chapter \ref{ch.international}.
If we seriously contemplated doing such a thing, it would quite probably be better
to put the panels in a two-fold
%%## libya is 4.72 or 5.07 kWh per day per m**2 camb is 2.64,2.82
sunnier country and send some of the energy home by power
lines. We'll return to this idea in \chref{ch.international}.
%\begin{figure}
% \figuremargin{
\marginfig{
\begin{center}
%\begin{tabular}{c}
{\mbox{\epsfbox{metapost/solar.4002}}} \\
%\end{tabular}
\end{center}
% }{
\caption[a]{Land areas per person in Britain.}\label{landareas}
}
%\end{figure}
% Total world PV peak (2006) is 6000 MW. 6GW.
% Ratio of peak to average in the UK would be (1/(3*4)) Use 10%.
% So to deliver 50 kWh/d/p is 125 GW, which is 1250GWp
% what is the weight of all that stuff? A 210Wp panel weighs 15kg.
% So to make 1GWp requires 71,429 tonnes of stuff
% To make 1GW average requires 714,000 tonnes of stuff
% cf nuclear power station: 67,000 tonnes steel plus
% 520\,000 cubic meters of concrete 2.3 tons per cu m
% so that is 1million tons of concrete
% it takes more energy to produce photovoltaic cells than the cells will ever produce throughout their lifetime.
\subsection{Mythconceptions}
%% http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%236163%232007%23999889998%23628382%23FLA%23&_cdi=6163&_pubType=J&view=c&_auth=y&_acct=C000050024&_version=1&_urlVersion=0&_userid=994540&md5=b446f1efb6701beb5729f8eb4fe3fdbe
%\qa{``The energy required to make a solar panel is
% much bigger than the energy it'll deliver.''}{
\qa{Manufacturing a solar panel consumes more
energy than it will ever deliver.}{
{\em False.}
The {\sl\OliveGreen{\ind{energy yield ratio}}\/}
(the ratio of energy delivered by a system
over its lifetime,
to the energy required to make it)
of a roof-mounted, grid-connected
solar system in Central Northern Europe is
\OliveGreen{4},
for a system with a lifetime\index{energy yield ratio!solar PV}
of 20 years \citep{EnergyYieldRatio};
% could also cite {WEAch7} page 21 of 54 chapter7.pdf
% Bath people say 4752 MJ/sqm embodied
% payback: 20Wmm 4752MJ/20W = 7.5 y
and more than \OliveGreen{7} in a sunnier spot such as Australia.
% ranges from 4 to 11, depending on the details of the
% system and the location.
% assuming 1000 kWh/m**2/y in northern europe
% assuming 1825 kWh/m**2/y in australia
(An \ind{energy yield ratio} bigger than
one means that a system is A Good Thing, energy-wise.)
% The Energy Yield Ratio of a solar system with lead acid battery is 3.
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}cc}
%% {\small\sc Consumption}& {\small\sc Production}\\
\multicolumn{2}{@{}c}{\mbox{\epsfbox{metapost/stacks.25}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Solar photovoltaics:
a 10\,m$^2$ array of building-mounted south-facing
panels with 20\% efficiency
can deliver
about 5\,kWh per day of electrical energy.
If 5\% of the country were coated with 10\%-efficient
solar panels
(200\,m$^2$ of panels per person)
they would deliver 50\,\kWh/\uday/\person.
% I relegate the second estimate to the right-hand column because
% I feel panelling the countryside in this way
%% it is implausible.
% goes beyond the bounds of plausibility.
}\label{fig.stack25}
}%
% \end{figure}
%From Rydh:
%
%How to define efficiency of an energy storage system.
%Let $E_O$ be the total energy it delivers in its life;
%let $E_D$ be the direct energy input during operation;
%let $E_I$ be the indirect energy, that is, the energy required
%to produce and install the system.
%Then the direct energy efficiency is $E_O/E_D$
%and the overall energy efficiency is $E_O/(E_D+E_I)$.
%
%
%Are photovoltaic systems worth it, in energy terms?
%Yes.
%For example, a PV-Li-ion battery system will replace 10
%%9.8
%times more
%energy throughout its life time than the energy
%required for production of the PV-battery
%system.
%% (as long as it's transported to the site of use by truck, not plane)
%% page 50 of his thesis
%For a lead-acid system, the energy return factor is
%not so good, but it's still bigger than one: it's about 5
%(and it drops to about 2.5 at an operating temperature of
%40\degreesC).
%% other storage technologies do not have such a
%% big temperature dpendence as the lead-acid.
Wind turbines with a lifetime of 20 years have an
energy yield ratio
\index{energy yield ratio!wind}
of
% return factor
\OliveGreen{80}.
% (They pay for themselves quicker, in energy terms.)
}
\qa{Aren't photovoltaic panels going to get more and more efficient as
\index{efficiency!improvements}technology improves?}{I am sure that photovoltaic panels
will become ever {\em{cheaper}};
I'm also sure that solar panels will become ever less energy-intensive
to {\em{manufacture}}, so their energy yield ratio
will improve. But this chapter's photovoltaic estimates
weren't constrained by the economic cost of the panels,
nor by the energy cost of their manufacture.
This chapter was concerned with the maximum conceivable power delivered.
Photovoltaic panels with 20\% efficiency
are already close to the theoretical limit
(see this chapter's endnotes). I'll be surprised if this chapter's
estimate for roof-based photovoltaics ever needs a significant upward revision.
}
% Donnachadh McCarthy in London has a 1.2kW solar electric PV from Sundog energy (fitted 1997)
% produces 1000 kWh / y ( 3 kWh/d )
% Wind TUrbine was A FAILURE Independent Thursday 27 December 2007. (makes
% 2 pounds per year and cost 2700)
% Solar HW: 1000 kWh (est)
% He uses 609 kWh of gas and 6400 of wood.
% See also biodiesel.tex for further notes.
%
% http://re.jrc.ec.europa.eu/pvgis/countries/europe/g13y_uk_ie.png
% EC diagram shows UK maximum sunshine is 1000 kWh/m**2, Min 750;
% that min is 86 W/mm.
% for cambridge this map seems to show
% 950 kWh /y ie 108.375575 W per (sq meter)
%
%http://lightbucket.wordpress.com/2008/02/24/insolation-and-a-solar-panels-true-power-output/
%
%42W/sq m on the map, and
%94 or so in the table.
% http://www.solaspin.com/1fd3ea50.gif
% Fig 1.: map showing average solar radiation on a 30° incline facing due south
% 1000 kWh/sq m/y
% 1000 kWh per year in W 114W.
%% Photosynthesis is only 12% efficient per se in transforming radiant energy to chemical energy
%%http://www.physics.ohio-state.edu/~aubrecht/energyblurb.html
%% http://www.thisissouthwales.co.uk/displayNode.jsp?nodeId=161818&command=displayContent&sourceNode=161644&contentPK=20580583&folderPk=88499&pNodeId=161375
%% story about public opposition to 4 new biomass stations in Wales
%% Mr Hughes said the wood for his two proposed power stations would come from the UK, Bosnia, Portugal and the United States, while Prenergy bosses said its wood would come from sustainable sources in North America.
\section{Solar biomass}
% \end{figure}
\myquote{All of a sudden, you know, we may be in the energy business
by being able to grow \ind{grass} on the \ind{ranch}! And have it harvested
and converted into energy. That's what's close to happening.}{George W. Bush, February 2006\index{Bush, George W.}}
%\end{quote}
% http://news.bbc.co.uk/1/hi/world/americas/4672216.stm
% Britain's area is 244,820 km^2 i.e. 0.24e6 km**2 i.e. 24e6 ha??
% 18.5e6 ha used for agriculture.
\noindent
All available bioenergy solutions involve first growing green
stuff, and then doing something with the green stuff.
How big could
the energy collected by the green stuff
possibly be?
There are four main routes to get energy from solar-powered biological
systems:\label{pBioOptions}
\ben
\item
We can grow specially-chosen plants and burn them in a power station
that produces electricity or heat or both. We'll\index{energy crops}
call this ``\ind{coal substitution}.''
\item
We can grow specially-chosen plants
(oil-seed rape, sugar cane, or corn, say),
turn them into \ind{ethanol} or \ind{biodiesel},\index{biofuel}
and shove that into cars, trains, planes
% internal combustion engines,
or other places where such chemicals are useful.
Or we might cultivate genetically-engineered bacteria,
cyanobacteria, or algae\index{hydrogen!from bacteria}
that directly produce hydrogen, ethanol, or butanol, or even
electricity.
We'll call all such approaches
``\ind{petroleum substitution}.''
%% Jim Schwartz synechocystis -- unicellular freshwater bacterium
%% Alfred Spormann - filamentous cyanobacteria
%% Algae? Fritz Prince and A. Grossman: algae for electricity
\item
We can take by-products from other agricultural activities and
burn them in a power station. The by-products might
range from straw (a by-product of \uk{\ind{Weetabix}}{\ind{Wheaties}})
%% Wheaties
to chicken poo (a by-product of \ind{McNuggets}).\index{chicken poo}
% poultry litter: installed capacity 13MW
% at Eye, Suffolk; and 39MW at Thetford.
Burning by-products is \ind{coal substitution} again,
but using ordinary plants, not the best high-energy plants.
A power station that burns agricultural by-products won't deliver
as much power per unit area of farmland as
an optimized biomass-growing facility, but it has the advantage
that it doesn't monopolize the land.
Burning \ind{methane} gas from \ind{landfill}
sites is a similar way
of getting energy, but it's sustainable only as long as we have
a sustainable source of junk to keep
putting into the landfill sites.\index{household waste incineration}
(Most of the landfill methane comes from wasted food; people in Britain throw\index{food!waste}\index{waste food}
away about 300\,g of food per day per person.\nlabel{foodwaste})
% http://news.bbc.co.uk/1/low/uk/7389351.stm
% UK throws away 3.6m tonnes food per year. DON@T USE THAT FIGURE
% that is 60 kg per person per year. which is 164g per day.
% BIGGER FIGURE HERE: We buy 1kg food per day. We chuck 306g of food per day. (using the 6.7 figure)
% [If use the 5.9 figure instead, which is the muniwaste part, we get 270g per day.] So 300g is a nice round number
% UK households waste 6.7 million tonnes of food every year, around one third of the 21.7 million tonnes we
%purchase. Most of this food waste is currently collected by local authorities (5.9 million tonnes or 88%). Some
%of this will be recycled but most is still going to landfill where it is liable to create methane, a powerful
%greenhouse gas. The remaining 800,000 tonnes is composted by people at home, fed to animals or tipped
% down the sink.
% http://news.bbc.co.uk/1/shared/bsp/hi/pdfs/foodwewaste_fullreport08_05_08.pdf
% from xpdf ~/sustainable/refs/biofuels/foodwewaste.pdf
% leading types of chucked food.
% (total was 6700kt)
% 359kt potato
% 328kt bread
% 190kt apples
% 161kt meat
% NB: 19% of UK municipal waste is food \cite{FoodWaste} They say 5.9Mt is the total food waste in the municipal waste.
% So that means the total muni waste must be 1.4 kg per person? Sounds bigger than I thought
% OK, I had 400 kg per person per year (1.1 kg per day)
% But Dajnak and Lockwood says 490kg? Ah, that is PER URBAN inhabitant
% On my euro graph page 222, I have total of UK landfill and incin
% is 1.2kg per d per person. If there is some recycling/compost-muni going on
% then I guess the total could be 1.4kg/d/p.
Incinerating household waste is another slightly less roundabout way
\index{waste incineration}of
getting power from solar biomass.\index{incineration!waste}
\item
We can grow plants and feed them directly to energy-requiring
humans or other animals.
\een
For all of these processes, the first staging post for the energy
is in a chemical molecule such as a \ind{carbohydrate}\index{photosynthesis}
in a green plant.
We can therefore estimate the power obtainable from any and all
of these processes by estimating how much power could pass through
that first staging post. All the subsequent steps involving
tractors, animals, chemical facilities, landfill sites, or power stations
can only lose energy. So the power at the first staging post is an
upper bound on
the power available from all plant-based power solutions.
So, let's simply estimate the power at the first staging post.
%% *** TENSE CONSISTENCY?
(In \chref{ch.solar2}, we'll go into more detail,
estimating the maximum contribution of each
process.)
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=50mm\epsfbox{../../images/miscanthusS.jpg.eps}}}%
{\mbox{\epsfxsize=50mm\epsfbox{../../images/miscanthus.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{Some {\em{\index{miscanthus}{Miscanthus}}\/} grass enjoying the company of
Dr Emily Heaton, who is 5'4" (163\,cm) tall.\index{Heaton, Emily}
%% http://miscanthus.uiuc.edu/wp-content/uploads/2007/01/heaton_sri_symposium_2007.pdf
In Britain, {\em{Miscanthus}\/} achieves a power per unit area of 0.75\,\Wmm.
Photo provided by the University of Illinois.\index{power density!miscanthus}
% *** MJB says remove this calculation from the caption , just keep the answer. DONE
% Miscanthus yields with no nitrogen fertilizer: 24 t/ha. (in USA?)
% Heaton, Voigt & Long 2004 Biomass and Bioenergy, 27:21-30 2004
% http://www.defra.gov.uk/erdp/pdfs/ecs/miscanthus-guide.pdf
}\label{fig.Miscanth}
}%
% \subsection{A quick bound on the whole lot}
%
The average harvestable power of sunlight
in Britain\index{biomass} is 100\,\Wmm. The most efficient plants in \ind{Europe}
are about 2\%-efficient at turning solar energy into carbohydrates, which would
suggest that plants might deliver 2\,\Wmm;
however, their efficiency drops at higher light levels,
and the best performance of any energy crops in \ind{Europe}
is closer
% if they then use half of this captured energy to run their own metabolism
% then these plants could
to \pdcol{0.5\,\Wmm}.\label{pBestPlants}
Let's cover 75\% of the country
with quality green stuff.\nlabel{cover75}
% I disabled this note. It is in _solar.tex
That's
3000\,\m$^2$ per person
%% CUTTABLE
devoted to
bio-energy.
%%% end cuttable
This is the same as the
%
\begin{figure}[bhtp]
\figuremarginb{
\begin{center}
{\mbox{\epsfbox{metapost/plants.155}} }\\
\end{center}
}{
%% MJB says ``power density'' is confusing
\caption[a]{Power production, per unit area, achieved by various plants.
For sources, see the\index{power density!plants}
% chapter's
end-notes.
These power densities vary depending on irrigation
and fertilization; ranges are indicated for some crops,
for example wood\index{wood}\index{trees} has a range from 0.095--0.254\,\Wmm.
The bottom three power densities are for crops
grown in tropical locations. The last power density (tropical plantations\Mahogany{$^*$})
% is for crops such as eucalyptus,
assumes \ind{genetic modification},
\ind{fertilizer} application, and \ind{irrigation}.
In the text, I use 0.5\,\Wmm\ as a summary figure
for the best energy crops in NW Europe.
% Transport requirement for moving biomass over land:
% \cite{WEAch5} 0.5 MJ per tkm
% so 100km maximum
% 1e9 J / hectare / year is 0.00316887 W/m**2
% From \cite{WEAch5}: NET ENERGY YIELDS GJ/ha/y W/mm
% SRC (willow, poplar; USA, Europe) 190 240 0.60 0.76
% Miscanthus/switchgrass 190 240 0.60 0.76
% Wood (commercial forestry) 30 80 0.095 0.254
% Sugar beet (NW Europe) 30 170 0.095 0.54
% Rapeseed (NW Europe) 70 135 0.22 0.43
% Sugarcane (Brazil, Zambia) 400 500 1.27 1.58
% Tropical plantations, eg eucalyptus 30 180 0.095 0.57
% Tropical plantations,
% with genetic modification,
% fertilizer, and irrigation 340 550 1.08 1.74
}\label{fig.plants155}
}
\end{figure}%
British land area
currently devoted
to agriculture.
So the maximum power available, ignoring all the additional costs of
growing, harvesting, and processing the greenery, is
\beqa
{0.5\,\Wmm \, \times \, \mbox{3000\,\m$^2$ per person}}
% & = & 1500\,\mbox{\W\ per person} \\
& = & 36\,\mbox{kWh/d per person} .
\eeqa
Wow.
That's not very much, considering the outrageously generous
% and infeasible
assumptions we just made, to try to get a big number.
If you wanted to get biofuels for cars
or planes from the greenery, all the other steps in the chain
from farm to \ind{spark plug} would inevitably be inefficient.
I think it'd be optimistic to hope that the overall losses
along the processing chain would be as small as 33\%.
Even
% just setting fire to
burning dried wood in a good wood boiler\index{efficiency!of incineration}\index{incineration!efficiency}
loses 20\% of the heat up the chimney.\label{pBoil80}
So surely the true potential power from biomass and biofuels
cannot be any bigger than \OliveGreen{24\,kWh/d per person}.
% which would correspond to a loss of just 33\%\ of the energy
% in processing.
And don't forget, we want to use some of the greenery to make
food for us and for our animal companions.
Could \ind{genetic engineering} produce plants that convert
solar energy to chemicals more efficiently? It's conceivable; but
I haven't found any scientific publication predicting
that plants in Europe could achieve net power production beyond
1\,\Wmm.
% of the plants that are discussed as candidates
% for the next generation of energy crops are
I'll pop
24\,kWh/d per person onto the green stack, emphasizing that
I think this number is an over-estimate -- I think the true maximum
power that we could get from biomass will be smaller because of the
losses in farming and processing.
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{cc}
% {\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.26}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Solar biomass, including all forms
of biofuel, waste incineration, and food:
24\,kWh/d per person.
% 400\,m$^2$ per person of biomass production
% offers
% about 5\,units per day.
}
}%
% \end{figure}
%
% \Chref{ch.solar2} looks in a little
% more detail at specific bio-solar solutions.
I think one conclusion is clear: {\em biofuels can't add up} --
at least, not in countries like Britain, and not as a replacement for
all transport fuels.
Even leaving aside biofuels' main defects -- that
their production competes with
% puts biofuel in competition with
food, and that the additional inputs required for farming and processing
often cancel out most of the delivered energy (\figref{fig.biofueld}) --
biofuels made from plants, in a European country like Britain,
can deliver so little power, I think they are scarcely worth talking
about.
% notes
% in quotes
%
% xpdf EnglishPartnerships2003.pdf
% say:
% 1ha -> 10 odt wood (from short rotation cop)
% and 1 odt -> 5 MWh (which is 18GJ) 5kWh per kg
% 50000 kWh / ha / year in W/m**2
% 0.57 W/m**2
% Cellulosic ethanol.
% from science editorial vol 312 page 1277
% USA could produce 1.3 billion dry tons of biomass per year
% in addition to current agri and forestry
% theoretically possible to get 100 gallons of ethanol per ton of cellulosic
% biomass. So could get 130 b gall of fuel ethanol. (which is almost
% the current consumption of transport fuel)
% difficulties: lignin difficult to remove. Ethanol poisons microorg's.
% see also DOE/GO-102005-2135 perlack et al
%% http://news.bbc.co.uk/1/low/sci/tech/7136486.stm
% Decision-makers in the climate change field have little faith in biofuels as a low-carbon technology, the World Conservation Union (IUCN) says
%\subsection{New biofuel diagrams}
% \input{algae.tex} moved to appendix solar2.tex
% cow power: a blogger said cow manure can give 3 kWh per day
%% Lots of good notes in here:
%% \input{biodiesel.tex}
%% \input{BushOnGrass.tex}
%\beginfullpagewidth
\small
\section*{Notes and further reading}
\beforenotelist
\pagebreak[0]%% nopagebreak
% We'll discuss trees and plants more in the second part of the book.
%
\begin{notelist}
\item[page no.]
\item[\npageref{latitude}]
{\nqs{\ldots compensate for
the tilt between the sun and the land}}.
% by multiplying by a factor of 0.6 (the \ind{latitude factor})}}.
The latitude of \ind{Cambridge}
is $\theta = 52\degrees$;
the intensity of
midday sunlight is multiplied by $\cos \theta \simeq 0.6$.
The precise factor depends on the time of year, and varies
between $\cos (\theta +23\degrees)= 0.26$ and $\cos (\theta-23\degrees)=0.87$.
\item[\npageref{sunniness}]
{\nqs{In a typical \UK\ location
the sun shines
during one third of daylight hours}}.
% used to have the areas here
\marginfig{
% \begin{figure}
%%% made by c4.m
\begin{center}
\begin{tabular}{@{}c}
\mbox{\epsfxsize=50mm%
\mono%
{\epsfbox{../data/cambridge/mono/HoursSunshine3.eps}}%
{\epsfbox{../data/cambridge/HoursSunshine3.eps}}%
}
\\
\end{tabular}
\end{center}
% }{
\caption[a]{Sunniness of Cambridge:
the number of \ind{hours of sunshine} per year, expressed
as a fraction of the total number of daylight hours.\index{data!sunniness}\index{sunniness}
}
\label{fig.sunniness}
}
The Highlands get 1100\,h sunshine per year -- a \ind{sunniness} of 25\%.
\begin{figure}[tbp]
\figuremargin{
\hspace*{-4mm}%
\begin{tabular}{c}
{\mbox{\epsfbox{metapost/solar.12}}} \\
\end{tabular}
}{
\caption[a]{% From solar energy to bioenergy.
% A reminder of the
This figure illustrates the quantitative
questions that must be asked of any proposed biofuel.
What are the additional energy inputs required for
farming and processing?
What is the delivered energy? What is the {\em net\/} energy output?
Often the additional inputs and losses wipe out most of the energy
delivered by the plants.
}\label{fig.biofueld}
}
\end{figure}
The best spots in Scotland get 1400\,h per year -- 32\%.
Cambridge: $1500\pm130$\,h per year -- 34\%.
% London: 1500\,h per year -- 34\%.
South coast of England (the sunniest part of the \UK): 1700\,h per year -- 39\%.
\tinyurl{2rqloc}{http://www.metoffice.gov.uk/climate/uk/location/scotland/index.html}
%% Berlin: 1837\,h. 42%. [which is 26% better than a 33% baseline]
%
% data from
Cambridge data from \tinyurl{2szckw}{http://www.metoffice.gov.uk/climate/uk/stationdata/cambridgedata.txt}.
See also \figref{fig.sunworld}.
% and \tabref{tab.sun}.
\setcounter{latestnotepage}{0}% hack to ensure page number given
\item[\npageref{p100W}]
{\nqs{ The average raw power of sunshine per square metre
of south-facing roof in Britain is roughly 110\,\nWmm,
and of flat ground,
roughly 100\,\nWmm}}.
Source: NASA ``Surface meteorology and Solar Energy''
% \myurlb{eosweb.larc.nasa.gov}{http://eosweb.larc.nasa.gov/},
\tinyurl{5hrxls}{http://eosweb.larc.nasa.gov/cgi-bin/sse/sse.cgi?+s01}.
Surprised that there's so little difference between
a tilted roof facing south and a horizontal roof? I was. The difference really is
just 10\%
\tinyurl{6z9epq}{http://www.solarcentury.com/knowledge_base/images/solar_pv_orientation_diagram}.
\item[\npageref{areaBuildings}]
{\nqs{\ldots that would be about
10\,m$^2$ of panels per person}}.
I estimated the area of south-facing roof per person
by taking the area of land covered by buildings per
person (48\,m$^2$ in England -- \tabref{tabLandAreas}), multiplying by $\dfrac{1}{4}$ to get the south-facing
fraction, and bumping the area up by 40\% to allow for roof tilt.
This gives 16\,m$^2$ per person.
Panels usually come in inconvenient rectangles so some fraction of
roof will be left showing; hence 10\,m$^2$ of panels.
\item[\npageref{pMythPV}]
{\nqs{The average power delivered by photovoltaic panels\ldots}}
\marginfig{
\begin{center}
\begin{tabular}{@{}c}
\mbox{\epsfxsize=53mm\epsfbox{../../data/sanyo.eps}} \\
\end{tabular}
\end{center}
\caption[a]{Power produced by
the Sanyo HIP-210NKHE1
module as a function of light intensity
(at 25\degreesC, assuming an output
voltage of 40\,V). Source: datasheet,
% http://www.sanyo-component.com
\myurlb{www.sanyo-solar.eu}{http://www.sanyo-solar.eu/}.
% http://www.sanyo-solar.eu/download-center.html
% http://www.sanyo-solar.eu/uploads/media/SANYO_HIP-210_205NKHE1_EN_screen.pdf
}\label{fig.sanyo}}
%
\begin{figure}
\figuremargin{
\raisebox{-8mm}[\textheight]{\epsfbox{../../data/solar/insol2.1}}
}{
\caption[a]{Average power of sunshine falling on a horizontal
surface in selected locations in Europe, North America,
and Africa.}\label{fig.sunworld}\vspace{1.65cm}\par
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=53mm\epsfbox{../../images/SolarPanel2S.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/SolarPanel2.jpg.eps}} \\
\end{tabular}
\end{center}
}
\end{figure}
There's a \index{myth!solar panels}myth going around that states that
solar panels produce almost as much power in cloudy\index{solar panels!on cloudy day}
conditions as in sunshine. This is simply not true.\index{cloudy day}\index{overcast day}
%
On a bright but cloudy day, solar photovoltaic panels
and plants do continue to convert some energy, but much less:
photovoltaic production falls roughly ten-fold
when the sun goes behind clouds (because the intensity of the incoming
sunlight falls ten-fold).
% 12\%
%% based on my observation of gauges at Machynlleth on a sun/cloud day.
%
% I expect that my
% under-estimate of photovoltaic production in cloudy conditions is
% compensated for by
As \figref{fig.sanyo} shows, the power delivered
by \ind{photovoltaic panels}
is almost exactly proportional to the intensity
of the sunlight -- at least, if the panels are at 25\degreesC\@.
To complicate
things, the power delivered
depends on temperature too -- hotter panels have reduced power (typically
0.38\% loss in power per \ndegreeC) --
% source sunpower
but if you check data from real panels, \eg\ at {\url{www.solarwarrior.com}},
you can confirm the main point: output on a cloudy day is {\em{far less}\/}
than on a sunny day. This issue is obfuscated by some solar-panel promoters
who discuss how the ``efficiency'' varies with sunlight. ``The panels are
more efficient in cloudy conditions,'' they say; this may be true, but
\index{efficiency!of solar panels}efficiency should not
be confused with\index{confusion!power and efficiency}
delivered\index{power!confused with efficiency}
power.\index{efficiency!confused with power}
\item[\npageref{pv20}]
{\nqs{
Typical solar panels have an efficiency of about 10\%;
expensive ones perform at 20\%.}}
See \figref{plants99}. Sources: \cite{WEAch7}, Sunpower
\myurlb{www.sunpowercorp.com}{http://www.sunpowercorp.com/}, Sanyo
\myurlb{www.sanyo-solar.eu}{http://www.sanyo-solar.eu/},
Suntech.
\item[\npageref{pHopf}]
{\nqs{A device with
efficiency greater than 30\% would be quite remarkable}}.
This is a quote from \citet{HopfieldGollub1978},
who were writing about panels without concentrating mirrors or lenses.
The theoretical limit for a standard ``single-junction''
solar panel without concentrators,
the \ind{Shockley--Queisser limit}, says that at most 31\% of the energy
in sunlight can be converted to electricity \citep{SQ1961}.
%\marginfig{
\begin{figure}\small
\figuremargin{
\begin{center}
\begin{tabular}{cc}
\mbox{\epsfxsize=53mm\epsfbox{../../data/spectrum/Spec.eps}} &
\mbox{\epsfxsize=53mm\epsfbox{../../data/spectrum/SpecSQ.eps}} \\
{\small photon energy (eV) }
&
{\small photon energy (eV) }
\\
\end{tabular}
\end{center}
}{
\caption[a]{{\Black{}Part of Shockley and Queisser's explanation for
the 31\% limit of the efficiency of simple photovoltaics.
Left: the spectrum of midday sunlight.
The vertical axis shows the
power density in \Wmm\
% watts per square metre
per eV of spectral interval.
The visible part of the spectrum is indicated by the coloured section.
Right: the energy captured by a photovoltaic device with a
single band-gap at 1.1\,eV is shown by the tomato-shaded area. Photons
with energy less than the band-gap are lost. Some of the energy of photons
above the band-gap is lost; for example half of the energy of
every 2.2\,eV photon is lost.
Further losses are incurred because of inevitable radiation from
recombining charges in the photovoltaic material.
}}\label{fig.ShockExpl}% *** this figure not referred to.
}
\end{figure}
% reference: Science 8 Feb 2008 vol 319 page 718
(The main reason for this limit is that a standard solar material
has a property called its band-gap, which defines a particular energy of photon
that that material converts most efficiently. Sunlight contains photons with
many energies; photons with energy {\em{below}\/} the band-gap are not used at all;
photons with energy {\em{greater}\/} than the band-gap may be captured, but
all their energy in excess of the band-gap is lost.)
%
Concentrators (lenses or mirrors)
can both reduce the cost (per watt) of photovoltaic
systems, and increase their efficiency. The \ind{Shockley--Queisser limit}
for solar panels with concentrators is 41\% efficiency.
%% http://www.sunpowercorp.com/
%% claim 23%
% they did Bavaria and Nellis and Serpa and lots in Spain
%%http://www.sunpowercorp.com/For-Power-Plants/Case-Studies.aspx
The only way to beat the Shockley--Queisser limit is to make fancy photovoltaic
devices
that split the light into different wavelengths, processing each wavelength-range
with its own personalized band-gap. These are called \ind{multiple-junction photovoltaics}.
% theory: 68ish without concentration and 86ish with.
Recently multiple-junction photovoltaics
with optical concentrators
have been reported
to be about 40\% efficient.
\tinyurl{2tl7t6}{http://www.reuk.co.uk/40-Percent-Efficiency-PV-Solar-Panels.htm},
\myurlb{www.spectrolab.com}{http://www.spectrolab.com/}.
%http://www.spectrolab.com/com/news/news-detail.asp?id=172
% 25th July 2007
\amarginfig{c}{
% \begin{figure}
\begin{center}
{\mbox{\epsfbox{metapost/plants.99}} }\\
\end{center}
% }{
\caption[a]{Efficiencies of
solar photovoltaic modules available
for sale today.
In the text I assume that roof-top
photovoltaics are 20\% efficient, and that country-covering
photovoltaics would be 10\% efficient.
In a location where the average power per unit area of incoming
sunlight is 100\,\Wmm, 20\%-efficient panels deliver
\pdcol{20\,\Wmm}.\index{power density!photovoltaics}
}\label{plants99}
}%
% \end{figure}
%
In July 2007, the \index{Delaware, University of}University
of Dela\-ware reported 42.8\% efficiency with
20-times concentration
\tinyurl{6hobq2}{http://www.azonano.com/news.asp?newsID=4546},
\tinyurl{2lsx6t}{http://www.udel.edu/PR/UDaily/2008/jul/solar072307.html}.
In August 2008,
NREL reported 40.8\% efficiency with 326-times concentration
\tinyurl{62ccou}{http://www.nrel.gov/news/press/2008/625.html}.
Strangely, both these results were called world efficiency records.
%http://empoweringsolar.blogspot.com/2007/07/new-solar-cell-record-428-efficiency.html
%http://www.scienceagogo.com/news/20070625035707data_trunc_sys.shtml
%
% http://discoverpower.com/shop/SOLAR_ELECTRIC_PANEL_UNBREAKABLE_cheap.asp
What multiple-junction devices are available on the market?
Uni-solar sell a thin-film triple-junction 58\,W(peak) panel with
an area of
% 1.258*0.793
%ans = 0.99759
1\,m$^2$. That implies an efficiency, in full sunlight, of only
5.8\%.
% their PV laminates: http://www.uni-solar.com/interior.asp?id=102
% http://www.uni-solar.com/uploadedFiles/0.4.1_pvl_136_tech_data_sheet.pdf
% 2.16m**2 = 5.486 * 0.394, weight 7.7kg, delivers 136W peak (at 1000 Wmm)
% That's 6.3% efficient.
% and 105W at 800 Wmm that is 6% again
% they say it has a ``higher yield'' than crystalline by using the
% metric of kWh per kWp (845 kWh per kWp) (per yr presumably)
\item[\npageref{fig.girton}] {\nqs{\Figref{fig.girton}:
Solar PV data}}.
Data and photograph kindly provided by
Jonathan Kimmitt.
\item[\npageref{pHelio}]
{\nqs{Heliodynamics}} -- \myurlb{www.hdsolar.com}{http://www.hdsolar.com/}.
See \figref{fig.helio}.
A similar system is made by Arontis \myurlb{www.arontis.se}{http://www.arontis.se/}.
\item[\npageref{pBavaria}]
{\nqs{The
\ind{Solarpark} in
\index{Muhlhausen@M\"uhlhausen}{Muhlhausen}, \ind{Bavaria}}}.
On average this 25-hectare farm is expected to deliver 0.7\,MW
(17\,000\,kWh per day).
% BIPV in new york subway station
% 250,000 kWh / 7060 sq m / year is 4 Wmm
% source
New York's Stillwell Avenue subway station has
integrated amorphous silicon thin-film photovoltaics in
its roof canopy, delivering \pdcol{4\,\Wmm} \citep{solarReview}.
% http://www.optisolar.com/
% make solar pv farms (thin film) in north america
% no details of area or TWh
The Nellis solar power plant in Nevada was completed in December, 2007, on 140 acres, and
% It is the largest solar photovoltaic system built in North America and is located at Nellis Air Force Base in Clark County, Nevada. It includes approximately 70,000 solar panels and the peak power generation capacity of the plant will is approximately 15 megawatts.
% 24,000 tons COO/y $1M per y
% 25e6 kilowatt-hours / year / 140 acres in watts per m**2
% 5 Wmm
% 30e6 kilowatt-hours / year / 140 acres in watts per m**2
is expected to generate 30\,GWh per year.
% source:
% 30million from
That's \pdcol{6\,\Wmm}
\tinyurl{5hzs5y}{http://www.ens-newswire.com/ens/dec2007/2007-12-26-093.asp}.
%% http://www.prnewswire.com/cgi-bin/stories.pl?ACCT=ind_focus.story&STORY=/www/story/04-23-2007/0004571089&EDATE=MON+Apr+23+2007,+08:00+AM
%% this gave 5Wmm
% cost was 100M, and they will pay 2.2c per kWh and 25 million kilowatt-hours per yr
% and 14 MW peak.
% 7 dollars per watt
% income of 0.55 M per year.
%\item[] Further pointers for low-cost solar photovoltaics:
% \myurl{http://www.nanosolar.com/} claim 14% efficient printed cells
% they have one machine producing GW per y
% \myurl{http://www.amonix.com/}
% \item[\npageref{pSolarfarming}]
% {\nqs{solar farming}} --
%numbers from
Serpa Solar Power Plant, Portugal (PV),
``the world's most powerful solar power
plant,''\index{solar photovoltaics!biggest plant in world}
\tinyurl{39z5m5}{http://news.bbc.co.uk/1/hi/world/europe/6505221.stm}
\tinyurl{2uk8q8}{http://www.powerlight.com/about/press2006_page.php?id=59}
has sun-tracking panels occupying
60 hectares, i.e., 600\,000\,m$^2$ or 0.6\,km$^2$,
%`11MW'.
%`8000 homes' (so 1 home is 0.3 kW).
expected to generate
20 GWh per year, \ie,
% 2300\,kW average;
2.3\,MW on average. That's a power per unit area of \powerd{3.8\,\Wmm}.
% Cost \$75\,million. (\$33\,000 per kW.)
% 30,000 tonnes of GHG per year.
%% Serpa.png
%% (20 (GWh per year)) / (60 ha) = 3.80265176 W per (m ** 2)
%The same company did Bavaria Solar Park.
%`10\,MW capacity', 62 acres,
%25 ha of farmland. Expected to produce 10\,GWh per year.
%(27\,000\,kWh per day; 1.1\,MW).
% That's 4.6W/m**2 of land
%% pr 10000000/365.25 / 24.0 / 0.25e6 * 1e3
%Of which 6.3\,MW is in the picture
%BavariaSolar.png
% http://www.solarbuzz.com/news/NewsEUPR265.htm
%% http://www.solarbuzz.com/
%% cost of solar modules is currently $4.85 per watt peak.
%% solar electricity costs 21 cents per kWh
\item[\npageref{worldPV}]
{\nqs{
The solar power capacity required to
deliver 50\,kWh/d per person in the UK is more than 100 times
all the photovoltaics in the whole world}}.
To deliver 50\,kWh/d per person in the UK would require 125\,GW average
power, which requires 1250\,GW of capacity.\index{solar photovoltaics!world total}\index{world solar power}
At the end of 2007, world installed photovoltaics
amounted to
10\,GW peak; the build rate is roughly 2\,GW per year.
% this plan requires 125GW average production, which
\item[\npageref{pPVfarmImplaus}]
{\nqs{\ldots
paving 5\% of this country with solar panels
seems beyond the bounds of plausibility}}.
My
% QUERY - how come this caption is not coming out SMALL??? ***
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}c}
\mbox{\epsfxsize=52mm\epsfbox{../../images/hdsolar.eps}} \\
\end{tabular}
\end{center}
% }{
\caption[a]{A combined-heat-and-power photovoltaic
unit from
\ind{Heliodynamics}.
A reflector area of 32\,m$^2$
(a bit larger than the side of a
double-decker bus) delivers
%% cf 12ft. 5in. High. 6ft. 11in.
%% london bus. 3.8 high , 1.85m wide
%% and 10m long.
up to 10\,kW of heat and 1.5\,kW
of electrical power.
In a sun-belt country,
one of these one-ton devices could
deliver about \OliveGreen{60\,kWh/d} of heat
and \OliveGreen{9\,kWh/d} of electricity.
%% http://www.hdsolar.com/combined_heat_and_power.php
These powers correspond to
average fluxes of {80\,\Wmm} of heat
and {12\,\Wmm} of electricity (that's per square metre of
device surface); these fluxes
are similar to the
fluxes delivered by standard solar heating panels
and solar photovoltaic panels, but
Heliodynamics's concentrating
design delivers power at a lower cost,
because most of the material is simple flat glass.
For comparison, the total power consumption of
the average European person is \Red{125\,kWh/d}.
}\label{fig.helio}
}%
main reason for feeling such a panelling of the country would be implausible
is that Brits like using their countryside for farming and recreation rather than
solar-panel husbandry. Another concern might be price.
This isn't a book about economics, but here are a few figures.
Going by the price-tag of the Bavarian solar farm,
to deliver 50\,kWh/d per person would cost \euro91\,000 per person;
if that power station lasted 20 years without further expenditure, the wholesale cost of the
electricity would be \euro0.25 per kWh.
% [full ROC price including CCL: 47 pounds per MWh]
% that is 0.19 pounds per kWh... 190 pounds per MWh offshore wind is 90 pounds per MWh, right?
% cf 45 pounds per MWh which is 0.045 pounds which is 0.06 euro
% cut to _solar.
Further reading:
David Carlson, BP solar \tinyurl{2ahecp}{http://www.aps.org/meetings/multimedia/upload/ The_Status_and_Outlook_for_the_Photovoltaics_Industry_David_E_Carlson.pdf}.
% Reference: Science 8 Feb 2008 vol 319 page 718 ``Can the upstarts top silicon?''
% has cost per W: $22 in 1980, $6 in 1990 and $2.70 in 2005, all in 2002 dollars.
%%% end of PV notes
%% begin biomass notes
\item[\npageref{foodwaste}]
{\nqs{People in Britain throw
away about 300\,g of food per day.}}
Source: \cite{FoodWaste}.\index{waste food}\index{food waste}
\item[\npageref{fig.Miscanth}] {\nqs{\Figref{fig.Miscanth}}}.
In the USA, {\em{Miscanthus}\/} grown without nitrogen \ind{fertilizer} yields
about 24\,t/ha/y of dry matter.\index{plant yields}\index{biomass!yields}\index{yield}
In Britain, yields of 12--16\,t/ha/y are reported. Dry {\em{Miscanthus}\/} has
a net \ind{calorific value} of 17\,MJ/kg, so the British yield
% (could include a COST of 338MJ/t ie 0.338 MJ/kg
corresponds to a power per unit area of 0.75\,\Wmm.
% that is odt
% {\em{Miscanthus}\/} data are from
Sources:
\citet{Miscanth}
% Heaton, Voigt \& Long (2004) Biomass and Bioenergy, 27:21-30 2004
and
\tinyurl{6kqq77}{http://www.defra.gov.uk/erdp/pdfs/ecs/miscanthus-guide.pdf}.
The estimated yield is obtained only after three years of undisturbed growing.
\item[\npageref{pBestPlants}]
{\nqs{The most efficient plants are about 2\% efficient;
but the delivered power per unit area is about 0.5\,\nWmm}}.
% Actually,
{\em At low light intensities}, the best British plants
are 2.4\% efficient in well-fertilized fields
\citep{monteith77} but at higher light
intensities, their conversion efficiency drops.
According to \citet{WEAch7} and \cite{NatureWorldElec}, the conversion efficiency of solar to biomass energy
is less than 1\%.
%%% would like to go fullpagewidth here
%\end{notelist}
%\beginfullpagewidth
%\begin{notelist}
%\item[]
Here are a few sources to back up my estimate of {\nqs{0.5\,\nWmm}} for
vegetable power in the UK\@.
The Royal Commission on Environmental Pollution's estimate
of the potential delivered power per unit area
from energy crops in Britain is 0.2\,\Wmm\ \citep{RCEP}.
On page 43
% my page 49
of the Royal Society's biofuels document \citep{RSBio},
{\em\index{miscanthus}{Miscanthus}\/} tops the list, delivering about \pdcol{0.8\,\Wmm} of chemical power.
% 200\,GJ/ha/y of heat,
% low heating value
% which in my preferred units is 0.6\,\Wmm.
% Actually their figure for Miscanthus is a bit higher
% because they've allowed for a thermal efficiency of 80\%.
% So I should have said 0.8\,\Wmm. And this implies the efficiency is
% 1.6\% rather than 1\%.
% yield 28 t/ha/yr at 50\% moisture content. They cite Elsayed et al (2003).
% 0.634Wmm
% My figure of 0.5\,\Wmm\ is the average of these two.
In the World Energy Assessment published by the UNDP,
\citet{WEAch5} writes:
``Assuming a 45\% conversion efficiency to electricity and yields of 15 oven dry
\tonnes\ per hectare per year, 2\,km$^2$ of plantation
would be needed per megawatt of electricity of installed capacity
running 4,000 hours a year.''
That is a power per unit area of \pdcol{0.23\,\Wemm}. (1\,W(e) means 1 watt of electrical power.)
\citet{EnglishPartnerships2003} estimates that
\ind{short-rotation coppices} can deliver over 10 \tons\ of dry wood\index{wood}\index{trees}
per hectare per year, which
corresponds to a power per unit area of \pdcol{0.57\,\Wmm}. (Dry wood has a calorific
value of 5\,kWh per kg.)
According to \citet{Photosynth}\index{photosynthesis!efficiency},
the instantaneous efficiency of a healthy leaf in optimal
conditions can approach 5\%, but the long-term energy-storage
efficiency of modern crops is 0.5--1\%.
% \citet{Photosynth}
Archer and Barber suggest that by \ind{genetic modification}, it might be
possible to improve the storage efficiency of plants,
especially {\dem\ind{C4 plants}}, which have already
naturally evolved a more efficient\index{plants!C4}
photosynthetic pathway. C4 plants are mainly found in the \ind{tropics}
and thrive in high temperatures; they don't
grow at temperatures below 10\degreesC\@.
% so C3 trees are preferred in europe
Some examples of C4 plants
are \ind{sugarcane}, \ind{maize}, \ind{sorghum}, \ind{finger millet}, and \ind{switchgrass}.
% There's two classes of plants: C3 plants and C4 plants.
\citet{ZhuLongOrt} calculate that the theoretical limit for the
conversion efficiency of solar energy to biomass is 4.6\% for C3\index{C3 plants}\index{plants!C3}
photosynthesis at 30\degreesC\ and today's 380\,ppm atmospheric
\COO\ concentration, and 6\% for C4 photosynthesis.
% xpdf refs/solar/Long_eff_photosyn_08.pdf &
% They include a requirement for mitochondrial activity
% ``We assume 30% here as the
% minimum respiratory loss that might be achieved without
% otherwise adversely affecting plant growth.''
They say that the highest solar energy conversion efficiencies reported
for C3 and C4
crops are 2.4\% and 3.7\% respectively;
% across a full growing season
% 2, 21-23.
and, citing \citet{Boyer1982}, that the average conversion efficiencies of major crops in the US\index{USA!crops}
are 3 or 4
% three or four
times lower than those record efficiencies (that is, about 1\%
efficient).
% CHECK THIS TO GET MORE PRECISE THAN 1%
% http://www.sciencemag.org/cgi/content/abstract/sci;218/4571/443?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=+Boyer+JS+%22+Plant+productivity&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT
% reference 31.
% Boyer JS: Plant productivity and environment. Science 1982, 218:443-448.
One reason that plants
don't achieve the theoretical limit is that they have insufficient capacity
to use all the incoming radiation of bright sunlight.
% eg brighter than 25% or 50%
Both these papers \citep{ZhuLongOrt,Boyer1982}
discuss prospects for genetic engineering of more-efficient
plants.\index{plants!more efficient}\index{efficiency!of plants}
\item[\npageref{fig.plants155}]
{\nqs{\Figref{fig.plants155}}}.
The numbers in this figure are drawn from
\citet{WEAch5} (net energy yields of wood, rape, sugarcane, and tropical plantations);
\citet{BayerCropSci} (rape to biodiesel);
\citet{FrancisJatropha} and \citet{jatropha} (jatropha);
\citet{RisoBiofuels} (sugarcane, Brazil);
\citet{Schmer} (switchgrass, marginal cropland in USA); % 0.2Wmm
\citet{CornEthanolEnergyBalance} (corn to ethanol); % 0.02Wmm
\citet{RCEP};
\citet{RSBio};
\citet{EnglishPartnerships2003};
\citet{Photosynth};
\citet{Boyer1982};
\citet{monteith77}.
\item[\npageref{pBoil80}]
{\nqs{Even just setting fire to dried wood in a good wood boiler
loses 20\% of the heat up the chimney}.}
Sources: \cite{RSBio,RCEP}.
\end{notelist}
%\ENDfullpagewidth
%\input{notesalgae.tex}% moved to solar2.tex from solarnotes.tex
% cut
% \section{`Solar tower' in Manchester}
% _solar.tex contains notes from RHF lectures
\normalsize
\rset\chapter{\rcol{Heating and cooling}}
\label{ch.heating}
\marginfig{
%\begin{figure}
%\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
%%{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/housing1.eps}}} \\
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/houses2S.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/houses2.eps}}} \\
% removed this one Sun 24/8/08
%\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/houses3S.eps}}}%
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/houses3.eps}}} \\
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/houses5.eps}}} \\
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/houses4.eps}}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{A flock of new houses.}
% , yesterday.}
}
% \end{figure}
% Home is where the heart is.
% Home is also where over a third of our energy is expended.
% We spend about one third of our energy on
This chapter explores how much power we spend controlling the \ind{temperature}
of our surroundings -- at home and at work -- and on warming or cooling
our food, drink, \ind{laundry},\index{cooking} and dirty dishes.
\section{Domestic water heating}
% Let's estimate how much energy we might put into
% water-heating.
% One strategy is to identify the biggest contributor
% to the total, estimate it, then allow for all the other
% smaller contributors by beefing the estimate up
% a little -- by a factor of two, perhaps.
The biggest use of hot water in a house might be\index{hot water}\index{water!hot}
\ind{bath}s, \ind{shower}s, \ind{dishwashing}, or \index{clothes washing}{clothes-washing} -- it depends
on your lifestyle.
% Some people have one hot bath per day.
Let's estimate first
the energy used by taking a hot bath.
% Sun 19/10/08 my bath used 45.03-35.62 cuft of gas (or 45.03-35.09
% if we include the lost hot water in the pipes of the house)
% which is 3.2 kWh.
% my shower uses 1.3496 kWh SHOWER
\marginfig{
\begin{center}
{\mbox{\epsfxsize=53mm\epsfbox{inkscape/bath2.eps}}}
\end{center}
\caption[a]{The \ind{water} in a \ind{bath}.}
\label{fig.bath}
}
% \subsection{Bathing}
% For one
% a modest
% bath, t V \simeq
The volume of bath-water is $50\,\cm \times 15\,\cm \times 150\,\cm
\simeq 110\,\litre$.
% ; a generous bath might be twice that.
% Actually I measured my modest bath water and got 62.3\l.
% Sun 29/6/08 I did it again (data/bath) and got 55l. And the energy used was exactly 2.48kWh.
% So 5kWh for 110 l is grand.
%
% p 39 (bath at 55 C)
% Isn't this scalding hot? I wouldn't set foot in it...
Say the temperature of the \ind{bath} is 50\degreesC\ (120\,F) and
the water coming into the house is at 10\degreesC\@.
The \ind{heat capacity} of water, which measures how much
energy is required to heat it up, is $4200$\,\J\ per \litre\ per \ndegreeC.
So the energy required to heat up the water by
% $\Delta T =
$40\degreesC$ is
\[%beq
% C V \Delta T =
4200 \, \J/\litre/\ndegreeC \times 110 \,\litre \times 40\degreesC
\, \simeq \, 18 \,\MJ \,\simeq\, 5 \,\kWh .
% 5.775
\]%eeq
% the water coming into the house is at 5\,C.
% The heat capacity of water is $C = 4200\, \J/\litre/\C$.
% So the energy required to heat up the water by $\Delta T = 45\,\C$ is
%\beq
% C V \Delta T = 4200 \, \J/\litre/\C \times 110 \,\litre \times 45\,\C
% \simeq 21 \,\MJ \simeq 6 \,\kWh .
%% 5.775
%\eeq
So taking a bath uses about
\Red{5\,kWh}.
% total so far: 5
For comparison, taking a shower (30\,litres) uses about \Red{1.4\,kWh}.
% MJB says *** need to say duration
% kettles are 4.5% of domestic elec.
% source Energy Saving Trust June 2006
\subsection{Kettles and cookers}
Britain, being a civilized country, has a 230 volt
domestic electricity supply.
%
With this supply, we can use an electric
\ind{kettle}\index{civilization}\index{electricity!supply}
to boil several litres of water in a couple of minutes.
Such kettles have a power of 3\,kW\@.\amarginfignocaption{c}{
\small \begin{center}
\begin{tabular}{rcl}
230\,V $\times$ 13\,A
&=& 3000\,\W\\
\end{tabular}
\end{center}
}
% (\Boxref{box.kettle}).
%% uncivilized
Why 3\,kW? Because this is the biggest power that a
230 \ind{volt} \ind{outlet}\index{electricity}
can deliver without the current exceeding
the maximum permitted,
\ind{13 amps}\index{amps}.
In countries\index{countries!civilized}
where the voltage is 110 volts,
it takes twice as long to make a pot of \ind{tea}.
If a household has the kettle on for 20 minutes per day, that's
an average power consumption of
\Red{1\,kWh per day}. (I'll work out the next few items ``per household,''
with 2 people per household.)
% \subsection{Cooker}
One small ring on an electric cooker has the same power as a \ind{toaster}:
1\,kW\@. The higher-power hot plates deliver 2.3\,kW\@.
If you use two rings of the \ind{cooker}\index{stove} on full power
for half an hour per day, that corresponds to \Red{1.6\,kWh per day}.
A \ind{microwave} {oven}\index{kilowatt}
usually has its cooking power marked on the front:
mine says 900\,W,
% , which is nearly a kilowatt;
but it actually
{\em{consumes}\/} about 1.4\,kW\@.
%% \ or more.
% You can check this by imagining choosing between putting
% your hands in the toaster or on the ring
If you use the microwave for 20 minutes per day,
that's \Red{0.5\,kWh per day}.%
\amarginfig{b}{\small
\begin{center}
\begin{tabular}{@{}c@{}c@{}}
\small \begin{tabular}[b]{@{}p{22.5mm}}
Microwave: 1400\,W peak\\[19.5mm]
Fridge-freezer: 100\,W peak,\\
18\,W average \\
% remeasured Sat 15/12/07: 105W peak, average 3.96kWh/235h = 17W\@. Good. (16.8) (According to maplin)
% remeasured Sat 22/3/08: 1173 hours, 18.17 kWh - 15.5W - 0.37 kWh/d WINTER,house low
% remeasured summer: Wed 22 July 2009: new maplin meter:
% 1.059 kWh in 48hrs 01mins. - which is 22W.
~\\
\vspace{0pt}\\
\end{tabular}
&
\begin{tabular}[b]{@{}l@{}}
\lowres{\epsfxsize=26mm\epsfbox{../../images/gadgets/MicrowFridgeF.jpg.S.eps}}%
{\epsfxsize=26mm\epsfbox{../../images/gadgets/MicrowFridgeF.jpg.eps}} \\
\vspace{0pt}\\
\end{tabular}\\[-2mm]
\end{tabular}
\end{center}
\caption[a]{
Power consumption by a heating and a cooling device.\index{microwave}\index{fridge-freezer}\index{freezer}\index{refrigerator}
}
\label{figFF}
}
A regular \ind{oven} guzzles more: about 3\,kW
when on full.
% or even 6\,kW (when on full).
If you use the oven for one hour per day, and the
oven's on full power for half of that time,
that's \Red{1.5\,kWh per day}.\nlabel{pCooker}
% total so far: 5 + 3.5 = 8.5
% 1.8kW cooker measured by Nathaniel Taylor
%I've timed its warming up, with temperatures judged by occasionally
%twiddling the oven's thermostat to find the current on/off point.
% time(mins) temp(degC)
% 0 20
% 5 100
% 7? 150
% 10 200
%On reaching 200 degC, the cycle of the empty oven was about 180s
%on and 400s off, i.e. on for about 0.3 of the time, averaging less than
%600 W of heat loss. My wild guess of 0.5 in the previous email was
%not too bad.
% http://www.premiumappliances.co.uk/lacanche_macon.php
% little ovens: 1.8kW, grill 2.4kW
% elec oven + grill 2.5kW
% big gas ovens: 3.5kW
% oven examples: grill is 2.4 kW, oven is 1.8kW
% fan assisted electric ovens: 4kW common
% simmer oven, 1.1kW
% dual fuel cooker 5.4kW
% 4, 5 kW ovens . 2.3kW
% fan oven 2.4kW grill 2.9kW 5.3\,kW grill 2.2kW
% nominal power 3kW
% http://www.trade-appliances.co.uk/_5014336_Smeg_F67-7.html
\begin{table}[tbp]
\figuremargin{ \small
\begin{tabular}{ll*{3}{r@{\,}l}} \toprule
\multicolumn{2}{l}{Device} & \multicolumn{2}{c}{\hspace*{-3.2mm}power} & \multicolumn{2}{c}{time} & \multicolumn{2}{c}{energy} \\
& & & & \multicolumn{2}{c}{\hspace*{-3.2mm}per day} & \multicolumn{2}{c}{per day} \\
\midrule \multicolumn{2}{l}{Cooking}\\
& -- kettle & 3&kW & $\dfrac{1}{3}$&h & 1&kWh/d \\
& -- microwave & 1.4&kW & $\dfrac{1}{3}$&h & 0.5&kWh/d \\
& -- electric cooker (rings) & 3.3&kW & $\dfrac{1}{2}$&h & 1.6&kWh/d \\ %%% **
& -- electric oven & 3&kW & $\dfrac{1}{2}$&h & 1.5&kWh/d \\
\multicolumn{2}{l}{Cleaning}\\
& \begin{tabular}{@{}l@{}} -- washing machine\\ % with electric water heater
\end{tabular} &
2.5&kW & & & 1&kWh/d \\
& -- tumble dryer & 2.5&kW & 0.8&h & 2&kWh/d \\
& -- airing-cupboard drying & & & & & 0.5&kWh/d \\
& -- washing-line drying & & & & & 0&kWh/d \\
% when I run my clothes washer (cold-ish wash),
% the elec consumed is about 0.3kWh.
% when it is totally cold, 0.16kWh.
% Tue 7/10/08 see file wash for details. Elec was 0.41kWh
% gas was at most 1.5kWh for a 45C wash. In fact 0.41kWh
& \begin{tabular}{@{}l@{}}
-- dishwasher \\ % with electric water heater
\end{tabular} &
2.5&kW & & & 1.5&kWh/d \\ %
\multicolumn{2}{l}{Cooling}\\
& -- refrigerator & 0.02&kW & 24&h & 0.5&kWh/d \\
& -- freezer & 0.09&kW & 24&h & 2.3&kWh/d \\ %%% SHOULD I ADD THIS TO STACK?
& -- air-conditioning & 0.6&kW & 1&h & 0.6&kWh/d \\
% \midrule
\bottomrule
\end{tabular}
}{
\caption[a]{Energy consumption figures for
\index{clothes dryer}\index{tumble dryer}\index{oven}heating and cooling devices,
per household. }
% Times and energies per day are rough averages.}
\label{tab.domestic.elecH}
}
% Dishwashers use 20l and 1 or 1.2kWh per wash. The water is mainly at 60C
% though the final heat may be a bit more.
\end{table}
% When I used tumble dryer I think 1hr per wash was normal. 1 wash every 3 days.ok.
\subsection{Hot clothes and hot dishes}
A clothes washer, dishwasher, and tumble dryer all use a power
of about 2.5\,kW when running.
\amarginfig{b}{
% \begin{figure}
\begin{center}
\begin{tabular}{cc}
%{\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.251}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{The hot water total at both home and work --\index{bath}\index{shower}
including bathing, showering, clothes washing,\index{laundry}\index{clothes washing}\index{washing}
\ind{cooker}s, \ind{kettle}s,
\ind{microwave} oven, and \index{dishwashing}dishwashing --
is about 12\,kWh per day per person.
I've given this box a light colour
to indicate that this power could be
delivered by
% much of this energy is, or could be,
low-grade thermal energy.
}
}%
% \end{figure}
A clothes washer uses about 80\,litres of water per load,
with an energy cost of
about 1\,kWh if the temperature is set to 40\degreesC.
If we use an indoor airing-cupboard instead of a tumble dryer to dry
clothes, heat is still required to evaporate the water -- roughly 1.5\,kWh
to dry one load of clothes,\label{pAiring} instead of 3\,kWh.
% Spread over 3 days
% method of calculation:
% from 15 up 85 , boil, down 85
% (85 * 4.187) + 2257.92 - ( 1.87 * 85 )
% answer: 2454.9kJ of latent heat of vap at 15C.
% for 4kg of dry clothes the water added was 2.2kg
Totting up the estimates relating to hot water, I think it's
easy to use about \Red{12\,kWh per day per person}.%
%
% As usual, this is not
% an estimate of {\em{average}\/} consumption -- not everyone
% takes a daily bath, nor does everyone use clothes-washers and
% tumble-dryers this heavily.
\section{Hot air -- at home and at work}
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=35mm\epsfbox{../../images/gadgets/Heater2kW.jpg.S.eps}}%
{\epsfxsize=35mm\epsfbox{../../images/gadgets/Heater2kW.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
A big electric heater: 2\,kW\@.\index{fire, electric}
}
}%
Now, does more\index{air, hot}\index{hot air}
power go into making hot water and hot food, or into
making hot air via our buildings' \ind{radiator}s?
% , which are typically
% heated by burning natural gas?
% The same gas boiler that takes about ten minutes to generate
% a 6\,kWh bath might be on for 6 hours per day at
% full power keeping the
% house warm in winter; say 3 hours per day averaged.
% No, that's too much. Get data.
One way to estimate the energy used per day for hot air is
to imagine a building heated instead
by electric fires, whose powers\index{fire!electric}
are more familiar to us. The power of a small
electric \ind{bar fire} or \ind{electric fan heater}
is 1\,kW (24\,kWh per day).
In winter, you might need one of these per person to keep toasty.
In summer, none.
So we estimate that on average one modern person {\em{needs}\/}
to use 12\,kWh per day on hot air.
But most people use more than they need, keeping several rooms
warm simultaneously (kitchen, living room, corridor, and bathroom, say).
So a plausible consumption figure for hot air is about
double that:
\Red{24\,kWh per day per person}.
% total so far: 5 + 3.5 + 20 = 28.5
This chapter's companion \chref{ch.heating2}
contains a more detailed account of where the heat is going in a
building; this model makes it possible to predict the heat savings from
turning the thermostat down, double-glazing the windows, and so forth.
\marginfig{
\begin{center}
\begin{tabular}{cc}
% {\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.261}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Hot air total --
including domestic and workplace heating --
about 24\,kWh per day per person.
% I've given this box a light colour
% to indicate that this energy
% could be delivered as low-grade thermal energy.
% -- heat from burning gas, for example.
}
}
\subsection{Warming the outdoors, and other luxuries}
There's a growing trend
of warming the outdoors with \ind{patio heater}s.
% among muppets who haven't heard of sweaters.
% , which are used to warm the outdoors -- a remarkable aim!
Typical patio heaters have a power of 15\,kW\@.
%
So if you use one of these
% are in the habit of
% warming the outdoors with a patio heater
for a couple of hours every evening, you are using an extra \Red{30\,kWh per day}.
% Put on a sweater, muppet!
A more modest luxury is an electric blanket. An electric blanket for a double bed
uses 140\,W; switching it on for one hour uses \Red{0.14\,kWh}.
\section{Cooling}
\subsection{Fridge and freezer}
We control the temperatures not only of the hot water and
hot air with which we surround ourselves, but also of the cold
cupboards we squeeze into our hothouses.
My fridge-freezer, pictured in \figref{figFF},
consumes 18\,W on average -- that's roughly 0.5\,kWh/d.
% cut material here
\subsection{Air-conditioning}
In countries where the temperature gets above 30\degreesC,
\ind{air-conditioning} is viewed as a necessity, and the energy cost
of delivering that temperature control can be large.
% On large (cruise) passenger ships, roughly one third of the
% power goes on the airconditioning. (Need a source.)
% The power produced by the auxiliary engines is about 2.5\,MW\@.
%% Meyer Werft shipyard
% 93\,000\,ton, 294\,m {\em{Norwegian Pearl}},
% Norwegian Cruise Line, carrying 2394 passengers
% and 1100 crew,
%% so that's about 1kW each,
% diesel-eletric propulsion: $5 \times 14.4 =72$\,MW
% generators supplying 39\,MW of propulsion,
% cruising speed 25\,knots.
% Must emphasize how big \ind{air-conditioning} is, where people have it.
However, this part of the book is about British energy consumption,
and Britain's temperatures provide little need for air-conditioning
(\figref{fig.camb.temp}).
\begin{figure}[hbtp]
\figuremargin{
\begin{center}
\mono%
{\epsfxsize=\textwidth\epsfbox{../data/cambridge/mono/Cam2006Temp.eps}}%
{\epsfxsize=\textwidth\epsfbox{../data/cambridge/Cam2006Temp.eps}}%
%% made by load 'gnudd'
\end{center}
}{
\caption[a]{\ind{Cambridge} temperature in degrees Celsius, daily (red line),
and half-hourly (blue line) during 2006.
% Thanks to Digital Technology Group, Computer laboratory, Cambridge.
}
\label{fig.camb.temp}
}
\end{figure}
\index{heat pump}An
economical way to get air-conditioning is an \ind{air-source heat pump}.
A window-mounted electric air-conditioning unit for a single room
uses 0.6\,kW of electricity and (by heat-exchanger)
delivers 2.6\,kW of cooling. To estimate how much energy
someone might use in the \UK, I assumed they might switch such an
air-conditioning unit
on for about 12 hours per day on 30 days of the year.
On the days when it's on, the air-conditioner uses 7.2\,kWh.
% which corresponds to 1\,hour per day on average.
The average consumption over the whole year is \Red{0.6\,kWh/d}.
%% dd.dat, daily.pl
This chapter's estimate of the energy cost of cooling%
\marginfig{
\begin{center}
\begin{tabular}{cc}
%{\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.271}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Cooling total --
including a refrigerator (fridge/freezer)
and a little summer air-conditioning -- 1\,kWh/d.
}
}
-- 1\,kWh/d per person --
includes this air-conditioning and a domestic refrigerator.
Society also refrigerates food on its way from field to shopping basket.
I'll estimate the power cost
of the food-chain later, in \chref{ch.stuff}.
% omitted things: hairdryers, electric razor on charging stand, toothbrush.
\section{Total heating and cooling}
Our rough estimate of the total energy that one person
might spend on heating and cooling, including
home, workplace, and cooking, is
\Red{37\,kWh/d per person} (12 for hot water, 24 for hot air, and 1 for cooling).
% Allowing for a share of clothes-washing,
% tumble-drying, and dishwashing,
%% For ease of memorization,
% I'll round this up to 40\,kWh/d.
%\marginfig{
\begin{figure}\figuremargin{
\begin{center}
\mbox{\epsfxsize=103mm\mono%
{\epsfbox{../data/mono/newgas0.eps}}%
{\epsfbox{../data/newgas0.eps}}%
}\\
\end{center}
}{
\caption[a]{My domestic cumulative gas consumption, in kWh, each year from 1993 to 2005.
The number at the top of each year's line is the average
rate of energy consumption, in kWh per day.
To find out what happened in 2007, keep reading!
% could refer to fig.gas0
}
\label{fig.gas00}
}
\end{figure}
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{cc}
%{\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.27}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Heating and cooling --
about 37\,units per day per person.
I've removed the shading from this box
to indicate that it represents
power that could be delivered by low-grade thermal energy.
% consumption
% a lot of which is low-grade energy -- heat from
% burning gas, for example, for
% making hot air, hot water, and hot food.
% Low-grade energy could
% be provided by solar heat.
% It could also be provided by heat pumps at an electrical-energy
% cost significantly lower than the heat delivered.
}
}%
% \end{figure}
Evidence that this estimate is in the right ballpark,
or perhaps a little on the low side,
comes from my own
domestic gas consumption, which for 12 years
averaged 40\,kWh per day
(\figref{fig.gas00}).
At the time I thought I was a fairly frugal user of heating,
but I wasn't being attentive to my actual power consumption.
Chapter \ref{ch.smarth} will reveal how much power I saved
once I started paying attention.
Since heating is a big item in our consumption stack,
let's check my estimates against some national statistics.
Nationally, the average {\em domestic\/}
consumption for space heating, water, and cooking
in the year 2000 was 21\,kWh per day per person,
and\nlabel{pECUK}
consumption in the {\em service sector\/} for
heating, cooling, catering, and hot water was 8.5\,kWh/d/p.
% Further national data are given in this chapter's notes.
%\newpage
For an estimate of workplace heating,
let's take the gas consumption of the University of Cambridge in 2006--7:\nlabel{pCUgas}
16\,kWh/d per employee.
% In 2006--7, the University's gas consumption.
Totting up these three numbers, a second guess for the national
spend on heating is $21+8.5+16 \simeq 45$\,kWh/d per person, if
Cambridge University is a normal workplace.
Good, that's reassuringly close to our first guess of $37\,$kWh/d.
%\section{Domestic hot air}
%\subsection{Convection heater}
% A heater that makes hot air
% typically has a power of about 1 or 2\,kW\@.
% If a house is heated by electric convection heaters -- a bad idea, but
% many are! -- then maybe each person needs 1\,kW all the time, at least
% in the cooler months. If we say they have the heating on
% for half the year, we get an average consumption of 12\,kWh per day
% per person.
%
% The same hot air can also be created by burning gas.
\small
\section*{Notes and further reading}
\beforenotelist
\pagebreak[0]%
\begin{notelist}
\pagebreak[0]%
\item[page no.]
\pagebreak[0]%
\item[\npageref{pCooker}]
{\nqs{An oven uses 3\,kW}}.
Obviously there's a range of powers.
Many ovens have a maximum power of 1.8\,kW or 2.2\,kW\@.
Top-of-the-line ovens use as much as 6\,kW\@.
For example, the
Whirlpool AGB 487/WP
4 Hotplate Electric Oven Range
has a 5.9\,kW oven, and four 2.3\,kW hotplates. \par
\myurlb{www.kcmltd.com/electric_oven_ranges.shtml}{http://www.kcmltd.com/electric_oven_ranges.shtml}
\par
\myurlb{www.1stforkitchens.co.uk/kitchenovens.html}{http://www.1stforkitchens.co.uk/kitchenovens.html}
% http://www.twenga.co.uk/offer/102141516.html
% this smeg has 1.3kW+0.8kW+ fan element 2.6kW
% max power 2.65kW
\item[\npageref{pAiring}]
{\nqs{
An airing cupboard requires roughly 1.5\,kWh
to dry one load of clothes}.}
I worked this out by weighing my laundry: a load of clothes,
4\,kg when dry,
emerged from my Bosch washing machine weighing 2.2\,kg
more (even after a good German spinning).
The latent heat of vaporization of water at 15\degreesC\ is
roughly 2500\,kJ/kg.
% Spread over 3 days
% from 15 up 85 , boil, down 85
% (85 * 4.187) + 2257.92 - ( 1.87 * 85 )
% answer: 2454.9kJ of latent heat of vap at 15C.
% for 4kg of dry clothes the water added was 2.2kg
To obtain the daily figure in \tabref{tab.domestic.elecH} I assumed that one person
has a load of laundry every three days, and that this sucks valuable
heat from the house during the cold half of the year. (In summer,
using the airing cupboard delivers a little bit of air-conditioning, since the
evaporating water cools the air in the house.)
\item[\npageref{pECUK}]
{\nqs{Nationally, the average {domestic}
consumption was 21\,kWh/d/p;
consumption in the {service sector} was 8.5\,kWh/d/p.
}}
Source:
% These national averages are from
\cite{ECUK}.
%--
% Average domestic consumption for space heating, water, and cooking
% (2000): 21\,kWh/d/p.
% 48 Mtoe * 82% of which space 28 Mtoe;
% and for water: 11, cooking 2.5.
% I convert Mtoe/y/UK to kWh/d/p using *32/60
% that's 21 kWh/d/p
% Consumption in the service sector for
% heating, cooling, catering, hot water (2000):
%% thou toe
% retail 2400
% hotel, catering 3000
% education 2400
% offices 1800
% warehouses 1200
% government 900
% health 900
% sport 600
% other 2650
%% from p38
% total 15.850
% which is 8.5
% 8.5\,kWh/d/p.
%% SERVICE SECTOR ALL ENERGY:
% floor area of service sector buildings: 854 km**2
% 2005, total energy consumption: 19.320 M toe / y
% energy per person: 10.3 kWh/d.
% area per person: 14 sq m
% energy per unit area : 0.724 kWh/d/sq m = 30 \Wmm
\item[\npageref{pCUgas}]
{\nqs{
In 2006--7, Cambridge University's gas consumption was 16\,kWh/d per employee.
}}
The gas and oil consumption of the University of Cambridge (not including the
Colleges) was 76\,GWh in 2006--7.
I declared the University to be the place of work of
13\,300\,people (8602 staff and 4667 postgraduate researchers).
% plus 11.6 MWh of heat at Addenbrookes
% p18
Its electricity consumption, incidentally, was 99.5\,GWh.
Source: University utilities report.
%Thank you for the very kind comments. Paul Hasley was the principal author of the paper and I can
%confirm there are no confidentiality issues.
%Regards Martin D
% M.J.Dowling
%% http://www.ipsos-mori.com/publications/srireports/climatechange.php
%% An A rated dishwasher will use approximately 0.81 kWh (9 place settings) to
%% per programme
%% source: imeasure
%http://www.greenandeasy.co.uk/Upload/file/dishwashers_2008January18.pdf
%
%A study comparing energy use between hand washing and dishwashers
%http://www.mtprog.com/spm/download/document/id/598
\end{notelist}
\normalsize
% was Electricity see \input{electricity.tex} for missing material (industry)
\gset\chapter{\gcol{Hydroelectricity}}
\label{ch.hydro}
%
\marginfig{
\begin{center}
%
%\lowres{\epsfxsize=53mm\epsfbox{../../images/Nant_y_Moch_dam_04_AndrewDixonS.eps}}%
%{\epsfxsize=53mm\epsfbox{../../images/Nant_y_Moch_dam_04_AndrewDixon.eps}}\\
{\epsfxsize=53mm\epsfbox{../../images/nant-y-moch3.jpg.eps}}\\
\end{center}
\caption[a]{\ind{Nant-y-Moch} \ind{dam}, part of a 55\,MW
hydroelectric scheme in \ind{Wales}. Photo
by
% Andrew Dixon and
Dave Newbould, \myurlb{www.origins-photography.co.uk}{http://www.origins-photography.co.uk}.}
%% permission granted for web version but not for printed Wed 22/8/07
}
\index{hydroelectricity}\index{water power}\index{electricity!hydroelectric}%
% \ind\index{water power} is
% already being exploited nearly fully in the UK.
To make {hydroelectric power}, you need altitude,
and you need rainfall.
Let's estimate the total energy of all the rain
as it runs down to sea-level.
% (Bear in mind, in fact,
% that much of this water evaporates again.)
For this hydroelectric forecast, I'll divide Britain into two:
the lower, dryer bits, which I'll call ``the \ind{lowlands};'' and the
higher, wetter bits, which I'll call ``the \ind{highlands}.''
% -- understood to include places like
% the \ind{Lake District}, the \ind{Pennines}, and \ind{Wales}.
I'll choose \ind{Bedford} and \ind{Kinlochewe} as my representatives of these
two regions.
% \medskip \par
%\marginfig{
%\begin{center}
%\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/bedford.eps,angle=270}}
%\medskip \\
%\end{center}
%}%
Let's do the lowlands first.\index{Britain!rainfall}\index{England, rainfall}\index{highlands!rainfall}\index{lowlands!rainfall}
%
% \section{England}
To estimate the gravitational power of lowland rain,
we multiply the\nlabel{prainf}
% rate of
\ind{rainfall} in \ind{Bedford} (584\,\mm\ per year)\
%\marginfig{
%\begin{center}
%\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/rain.eps,angle=270}}\\
%\end{center}
%}
by the density of water (1000\,kg/m$^3$), the strength of gravity
(10\,m/s$^2$) and
the typical lowland altitude above the sea (say $100\,\m$).
The power per unit area works out to
0.02\,\Wmm.\index{power density!hydroelectricity}
That's the power per unit area of land on which rain falls.
%## pop area(sq.km) - country (2002)
%49561800 130423 380 England that is 2173 each
%2918700 20779 140 Wales 350 each
%5054800 78789 64 Scotland 1313 each
%## 59553800 244820 243 United Kingdom 4080 each
When we multiply this by the area per person (2700\,m$^2$,
% was 2200 then 2500
if the lowlands
% England and Wales
are equally shared between all 60 million Brits),
we find an average raw power
of about 1\,kWh per day per person.
% 50W = 1.25 kWh/d
This is the absolute upper limit for lowland hydroelectric power,
if every
river were dammed and every drop perfectly exploited.
Realistically, we will only ever dam rivers with substantial
height drops, with catchment areas much smaller than the whole country.
Much of the water evaporates before it gets anywhere near a turbine,
and no hydroelectric system exploits the full potential energy of the water.
We thus arrive at a firm conclusion about lowland water power.
People may enjoy making
``run-of-the-river'' hydro and other small-scale
hydroelectric schemes, but such lowland facilities can never deliver
more than 1\,kWh per day per person.
% (Bear in mind
% that the current
\begin{figure}[hbtp]
\figuremarginb{
\begin{center}
\mbox{\epsfbox{metapost/heights.21}}
\end{center}
}{
\noindent%
\raisebox{10.4cm}[0cm]{\epsfig{file=../../images/PUBLICDOMAIN/maps/bedford.eps,angle=270}}%
\par
\caption[a]{%
Altitudes of land in Britain.
The rectangles show how much land area there is
at each height.\index{heights}\index{Britain!heights}\index{area}\index{data!height}
}
}
\end{figure}
%%% Let's turn to
%\section{Scotland}
Let's turn to the highlands.
\ind{Kinlochewe} is a rainier spot:
it gets 2278\,\mm\ per year, four times more than Bedford.
The height drops there are bigger too -- large areas of land
are above 300\,\m.\index{Britain!rainfall}\index{Scotland!rainfall}
So overall a twelve-fold increase in power per square metre
is plausible for mountainous regions. The raw power per unit area is roughly\index{power density!highland hydroelectricity}\index{hydroelectricity!highland}\index{highland hydroelectricity}
$0.24\,\Wmm$.\nlabel{pLochSloy}
%%
%% typical figure 3,000 mm per year in the western Highlands
%% \tinyurl{2rqloc}{http://www.metoffice.gov.uk/climate/uk/location/scotland/index.html}
%%
%% The Lake District is the wettest part, with average annual totals exceeding 2,000 mm (this is comparable with that in the western Highlands of Scotland). The Pennines and the moors of south-west England are almost as wet. However, all of East Anglia, much of the Midlands, eastern and north-eastern England, and parts of the south-east receive less than 700 mm a year.
%%
If the highlands
generously share their hydro-power with the rest of the \UK\
(at 1300\,m$^2$ area per person),
we find an upper limit of about 7\,kWh per day per person.
As in the lowlands, this is the upper limit on raw power if
evaporation were outlawed and every drop were perfectly exploited.
What should we estimate is the plausible practical limit?
Let's guess 20\% of this -- 1.4\,kWh per day, and round it up a little to allow
for production in the lowlands: \OliveGreen{1.5\,kWh per day}.%
\amarginfig{b}{
% \begin{figure}
% \begin{center}
\mbox{\epsfbox{metapost/stacks.28}}
% \end{center}
% }{
\caption[a]{Hydroelectricity.}
}
%% (which is about 1\% of UK electrical power)
The actual power from hydroelectricity in the UK today
is\label{pHydro} 0.2\,kWh/d per person,
so this 1.5\,kWh/d per person would require a seven-fold increase
in hydroelectric power.
% Realistically, I don't imagine that Britain will ever get more than
% 0.6\,kWh/d/person from hydro.
%And from (what document? DTI?)
%the DTI's estimates, the hydro resource of the UK is 40 TWh/y.
%Which is 1.8\,kWh per day per person.
% \end{figure}
\small
\section*{Notes and further reading}
\beforenotelist
\begin{notelist}
% RESTORE ME IN 2nd EDITION!!!! ***
% \item[page no.] % ***
\item[\npageref{prainf}] {\nqs{Rainfall}} statistics are from the BBC weather centre.
\item[\npageref{pLochSloy}]
{\nqs{The raw power per unit area [of Highland rain] is roughly
$0.24\,\Wmm$.}}
We can check this estimate against the actual power per unit area of
the {Loch Sloy hydro-electric scheme}, completed in 1950 \citep{LochSloy}.
The catchment area of \ind{Loch Sloy} is\index{power density!hydroelectricity}
% 32\, sq mi
about 83\,km$^2$; the rainfall there is
% 115 inches per year
about 2900\,mm per year (a bit higher than the 2278\,mm/y of Kinlochewe);
and the
% annual electricity output was predicted to be 130\,GWh per year,
% (In fact in 2006 it produced 142\,GWh.)
electricity output in 2006 was 142\,GWh per year,
which corresponds to a power density of
% (130 (GWh / year)) / (32 (sq miles)) = 0.178938344 W / (m ** 2)
% (142 (GWh / year)) / (32 (sq miles)) = 0.1954 W / (m ** 2)
\pdcol{0.2\,\W\ per m$^2$} of catchment area.
Loch Sloy's surface area is about 1.5\,km$^2$, so
% , in case it's of interest, we can also work out the power density of the
the hydroelectric facility itself
% (130 (GWh / year)) / (1.5 (sq km)) = 9.88689457 W / (m ** 2)
% (142 (GWh / year)) / (1.5 (sq km)) = 10.8 W / (m ** 2)
% In our calculation we used TIGC = 152.5MW
% And Annual Output = 141.885 GWh
has a
per unit lake area of \pdcol{11\,\Wmm}.
So the hillsides, aqueducts, and tunnels bringing water to Loch Sloy
act like a 55-fold power concentrator.%
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=51mm\epsfig{file=../../images/DinorwigWheelS.jpg.eps,angle=270,width=53mm}}}
{\mbox{\epsfxsize=51mm\epsfig{file=../../images/DinorwigWheel.jpg.eps,angle=270,width=53mm}}}
\end{tabular}
\end{center}
\caption[a]{
% An 80\,horsepower (60\,kW) waterwheel
A 60\,kW \ind{waterwheel}.
% in \ind{Dinorwig}, North \ind{Wales}.
}\label{fig.bigWheel}
}
\item[\npageref{pHydro}]
{\nqs{The actual power from hydroelectricity in the UK today
is 0.2\,kWh per day per person.}}
% ,\label{pHydro}
%The actual generation of hydroelectricity in the UK
% in 2006 was 0.17\,kWh/d/person.}}
% page 130
Source: \citet{Dukes07}.
% , actual production of hydroelectricity in 2006 was:
In 2006,
large-scale hydro produced 3515\,GWh (from plant with a
capacity of 1.37\,GW);
small-scale hydro, 212\,GWh (0.01\,kWh/d/p) (from a capacity of 153\,MW).
% (3515+212)*1e6 / 60e6 / 365.25
% Source: BP statistical review of world energy.
% 1.7 million {\tonne}s of oil equivalent
% is 7.65\,\TWhe/y,
% which is 0.35\,\kWhe/day/person.
% (1\,M {\tonne}s of oil produces about 4.5\,TWhe\ in a modern power station.)
% This multiplier is not standard, sadly.
% In DUKES the standard multiplier is
% 1\,TWh of electricity = 0.086\,Mtoe.
% This means 1\,Mtoe = 11.6\,TWhe.
In 1943, when the growth
of hydroelectricity was in full swing,
the North of Scotland Hydroelectricity Board's engineers estimated
that the Highlands of Scotland could produce
% 6273\,GWh per year in 102 facilities.
6.3\,TWh per year in 102 facilities -- that would correspond to
0.3\,kWh/d per person in the UK \citep{LochSloy}.
%6273e6 / 365.25 / 60e6
%ans = 0.28624
%
% at the time they were already building facilities for 3 TWh per year
% http://www.reuters.com/article/pressRelease/idUS104835+07-Jan-2008+RNS20080107
Glendoe, the first new large-scale hydroelectric project in the UK
since 1957, will add capacity of 100\,MW
and is expected to deliver 180\,GWh per year.
% roughly 8% increase
Glendoe's catchment area is 75\,km$^2$, so its power density works out to
\pdcol{0.27\,\W\ per m$^2$} of catchment area.
\ind{Glendoe} has been billed as ``big enough to
power\index{myth!hydroelectricity}
% every home in a city the size of
Glasgow.''
% I bet that people get the impression from this that
% Glendoe will provide enough electricity ``to
% power \ind{Glasgow}.'' But this is a long way from the truth.
But if we share its 180\,GWh per year across the population of \ind{Glasgow}
(616\,000 people), we get only 0.8\,kWh/d per person. That is just
% 4.32 or 4.44
5\% of the average electricity consumption of 17\,kWh/d
per person.
% Total production 406,000 GWh 2006 including imports and pumped s.
% 18.5kWh/d/p. If omit pumped st get 18.3. Good I like 18.
% losses are 30.9. If we omit them too then we get 17kWh/d/p.
% Losses are 7.7%. 8% good enough.
% Final consumption 342,781 15.6 16kWh/d/p
% that figure omits ``energy industry use'', ``elec gen''...
% Rainfall is 2000 mm/y
% head is 630-21.4 m
% Can reach full output in 30 seconds.
%
% glendoe expected to deliver 180GWh per year
% 11.5 million cubic metres of water from a catchment area of75 square kilometres
% 180 GWh per year / 75 square kilometres in W/m**2
% 0.27379 W / (m ** 2)
The 20-fold exaggeration is achieved by focusing on Glendoe's {\em{peak}\/}
output rather than its {\em{average}}, which is 5 times smaller;
% which is factor of 5
and by discussing ``homes'' rather
than the total electrical power of Glasgow (see \pref{pHOME}).
\end{notelist}
\normalsize
%Rarely it reaches 1.9.
%Let's say 2? (Converted on the basis of thermal equivalence
%assuming 38\% conversion efficiency in a modern thermal power station)
%(cf total UK consumption was 227 million {\tonne}s of oil equivalent)
%(1M {\tonne}s of oil produces about 4.5TWh of elec in a modern power station)
%% (700/6e9/365) * 4.5e9
% example of tiny hydro scheme:
% http://news.bbc.co.uk/1/hi/scotland/tayside_and_central/7347001.stm
% The 1.4 megawatt Innerhadden Burn project will be two kilometres south east of Kinloch Rannoch.
% biggest capacity facilities in UK:
% Fasnakyle 69MW (affric)
% lochay 47MW (breadalbane)
% luichart 34MW (conon)
% glenmoriston 37MW (great glen)
% shin 19MW
% Sloy 153MW (sloy/awe)
% The calculated annual LF output for Loch Sloy Hydro for 2006 is 10.62%.
% 365 * 24 * 0.1062 * 0.153 GW
% 142.337736 GWh
% from Jim Oswald et al
% clachan 40MW
% tummel errochty 75MW
% clunie 61MW
% rannoch 44MW
% tongland 33MW
% SSE output from hydro: 2007/08 was 3,518GWh
% run of the river schemes are all sub 3MW (peak)
% glendoe expected to deliver 180GWh per year
% 11.5 million cubic metres of water from a catchment area of75 square kilometres
% 180GWh per year / 75 square kilometres in W/m**2
% 0.27379 W / (m ** 2)
% source:
% http://miranda.hemscott.com/ir/sse/ar2008/download/pdf/ar2008.pdf
% SSE 2008 Annual Report and Accounts
% it cost 140 million
% from http://www.ref.org.uk/Pages/4/uk_renewable_energy_data.html
%
% http://www.arrocharheritage.com/LochSloyHydroElectricScheme.htm
% % in 1935 they already planned
% to make Sloy reversible (pumped storage)
% this page shows the catchment area
% estimated output of Sloy:
% 130 GWh per year.
% natural catchment area: 6.5 sq mi;
% Increased to 27.5 sq mi, then
% to 32 sq mi by diversions
% This increased output by 15 GWh per y.
% the dam raised the level of
% loch sloy by 155 feet; it is 1160 ft
% long and 160 ft high.
% loch sloy stores 1200 M cu ft,
% equivalent to 20 GWh.
% each inch of rain yields 1.3GWh, assuming the reservoir is at 910 feet
% above turbines (ie full).
% 130MW of francis turbines and an extra 0.45MW pelton set.
% The Board's engineers estimated in 1943
% that the rivers and lochs of the
% Highlands could produce 6273 GWh
% per year, and the North of Scotland Hydro
% -Electric Board's development programme
% visualized the construction of 102 HE
% schemes.
% 19 schemes with capacity of 630MW
% and annual output of 1600 GWh have been
% promoted.
%
% Morar has a catchment area of 65 sq mi,
% rainfall 100 in per year.
% this is great!
% http://www.arrocharheritage.com/LochSloyHydroElectricScheme.htm
% Loch Morar could be raised 8 feet.
% Head is 16 feet at present.
% Lochalsh: head is 490ft. 1MW
% there could be 2nd dam.
% is linked to Storrs Lochs hydro station in Skye
% Tummel-Garry scheme to produce 300GWh/y
% (Extension of rannoch scheme from 1930s)
% Catchment area 706 sq mi
% Errochty reservoir is at 1100 ft above sea level
% aqueduct from rivers Bruar and Garry
% Clunie station 61MW. started 1950
% Mullardoch-Fasnakyle-Affric,
% catchment area 124 sq mi, 223 GWh/y
% 66MW
% Conon, Loch Fannich. output expected (includes loch Maree)
% 437GWh/y.
% Glascarnoch-Luichart-Torr Achilty sceme
% 60MW, estd output 280GWh/y.
% Grudie Bridge, 24MW, 83 GWh/y.
% Glen Shira, 100 GWh/y - planned to
% have pumped storage
% Cowal: 14 GWh/y
% Gairloch
% Glen Garry : 145GWh/y.
% Glen Morriston: 214GWh/y.
% Gaur scheme - 17GWh/y
% Lawers: 1362ft head, power station at Killin end of
% Loch Tay (top loch called Lochan-na-Lairige)
% 71 GWh
% List of schemes under construction
% Schemes promoted but not yet started
% biggest ones are Glascarnoch (112), Luichart (124), Quoich (63GWh),
% Invergarry (82GWh), Invermoriston (75GWh), Lawers (71GWh)
% the lists show catchment areas and heads and rainfalls
% SCHEMES UNDER SURVEY
% Lyon-Lochay 195GWh/y, Lednock-Earn 87;
% Shin: 164;
% further schemes: 883 GWh
% Total: 409MW and 1436GWh under survey.
%
% http://rls.org.uk/database/record.php?usi=000-000-001-499-L
% Al smelting started at Foyers
% 1896
% 1903-1907 Kinlochleven Blackwater Dam
% Hydro building for the public started in 1927.
% Really got going (under Tom JOhnston) in 1943.
% Cruachan 1967 in side a cavern
% conon built 1946-61
% from 1945 to 1970, homes connected went from 0% to 90%
\rset\chapter{\rcol{Light}}
\label{ch.lighting}
\label{ch.light}
% lighting is 16% of domestic elec.
% source blueprint p290
\section{Lighting home and work}
% \subsection{Light bulbs}
%% CFL
The brightest domestic lightbulbs use 250\,W, and
% or $\dfrac{1}{4}$\,\kW;
bedside lamps use 40\,W\@.
In an old-fashioned incandescent bulb, most of this power gets
turned into heat, rather than light.
A fluorescent tube can produce an equal amount of light using one quarter
of the power of an incandescent bulb.
%% http://www.bchydro.com/powersmart/elibrary/elibrary680.html
%% only
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{cc}
% {\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.280}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Lighting -- 4\,kWh per day per person.
}
}
% \end{figure}
\begin{table}\figuremargin{
\begin{tabular}{l*{3}{r@{\,}l}} \toprule
Device & \multicolumn{2}{c}{Power} & \multicolumn{2}{c}{Time per day} & \multicolumn{2}{c}{Energy per day} \\
& & & & & \multicolumn{2}{c}{per home} \\
\midrule
10 incandescent lights & 1&kW & 5&h & 5&kWh \\
10 low-energy lights & 0.1&kW & 5&h & 0.5&kWh \\
\bottomrule
\end{tabular}
}{
\caption[a]{Electric consumption for domestic lighting.
A plausible total is 5.5\,kWh per home per day;
and a similar figure at work; perhaps
4\,kWh per day per person.}
\label{tab.domestic.elecL}
}
\end{table}
How much power does a moderately affluent person use for lighting?
My rough estimate, based on table \ref{tab.domestic.elecL}, is
that a typical two-person home with a mix of low-energy
and high-energy bulbs uses about 5.5\,kWh per day, or
2.7\,kWh per day per person.
% (assuming two persons to a home).
I assume that each person also has a workplace where they
share similar illumination with their colleagues;
% At work, a similar figure,
% though perhaps workplaces are a bit more efficient than
% homes? Let's
guessing that the workplace uses 1.3\,kWh/d per person,
we get a round figure of \Red{4\,kWh/d per person}.
\section{Street-lights and traffic lights}
Do we need to include public lighting too, to get an accurate estimate,
or do home and work dominate the lighting budget?
Street-lights in fact use about\label{pStreetL} 0.1\,kWh per day per person,
and traffic lights only\label{pStreetL2} 0.005\,kWh/d per person
-- both negligible, compared with our home and workplace lighting.
% , so we can ignore them.
%
What about other forms of public lighting
-- illuminated signs and bollards, for example?
There are fewer of them than street-lights\nlabel{pfewerbollard};
and street-lights already came in well under our radar, so
we don't need to modify our overall estimate of 4\,kWh/d per person.
% cars
\section{Lights on the traffic}
In some countries, drivers must switch their lights on
\index{car!lights}\index{lights, on cars}whenever their car is moving.
How does the extra power required by that policy
compare with the power already being used to trundle the car around?
%% Conventional dipped headlamps use 50 watts each, but sidelights 12 watts. Daytime running lights need not be as
% +bright as dipped headlights but need to be brighter than sidelights - so say 24 watts each
Let's say the car has four incandescent lights totalling 100\,W\@.
The electricity for those bulbs is supplied by a 25\%-efficient engine
%% http://en.wikipedia.org/wiki/Alternator
powering a 55\%-efficient generator\nlabel{pAltern}, so the power required is \Red{{730\,W}}.
For comparison, a typical car going at an average speed of 50\,km/h
and consuming one \litre\ per 12\,\km\ has an average power consumption of \Red{{42\,000\,W}}.
So having the lights on while driving requires 2\% extra power.
%% 42 kWh per h.
What about the future's electric cars?
%% 50* 9.0/80
%% 50 km/h * 9.0 kWh /80 km
%% 5.625kWh/h GWiz sustained power is 4800
The power consumption of a typical electric car is about 5000\,W\@.
So popping on an extra 100\,W would increase its consumption by 2\%.
Power consumption would be smaller if we switched all car lights to light-emitting
diodes, but if we pay any more attention to this topic, we will
be coming down with a severe case of \index{every little helps}every-little-helps-ism.
\section{The economics of low-energy bulbs}
Generally I avoid discussing economics,
but I'd like to make an exception for lightbulbs.
% Bulb comparison:
Osram's 20\,W low-energy bulb claims the same light output as a
100\,W incandescent bulb.\index{bulb!incandescent}\index{lightbulb!incandescent}
Moreover, its lifetime is said to be 15\,000\,hours (or ``12 years,''
at 3\,hours per day).
In contrast a typical incandescent bulb might last 1000 hours.%
\marginfig{
\mbox{\epsfbox{metapost/bulbs.21}%}%% mpost bulbs ; latex wrapper2 ;
\makebox[0in][r]{%
\raisebox{72mm}{\epsfxsize=20mm\lowres{\epsfbox{../../images/Bulbs20C.jpg.eps}}%
{\epsfbox{../../images/Bulbs20.jpg.eps}}}
\hspace*{16.5mm}}
}
\caption[a]{Total cumulative cost
of using a traditional incandescent 100\,W bulb
for 3 hours per day,
compared with replacing it {\em{now}\/} with
an Osram Dulux Longlife Energy Saver (pictured).
Assumptions: electricity costs 10p per kWh; replacement traditional bulbs
cost 45p each; energy-saving bulbs cost \pounds9. (I know you can find
them cheaper than this, but this graph shows that even
at \pounds9, they're much more economical.)
}\label{fig.bulbchoi}
}
%
So during a 12-year period, you have this choice (\figref{fig.bulbchoi}):
buy 15 incandescent bulbs and 1500\,kWh of electricity
(which costs roughly \pounds 150);
or buy one low-energy bulb and 300\,kWh of electricity
(which costs roughly \pounds 30).\index{bulb!low-energy}\index{lightbulb!low-energy}
% Here's a question I should
\qa{Should I wait until the old bulb dies before replacing it?}%
{It feels like a waste, doesn't it? Someone put resources into making
the old incandescent lightbulb;
shouldn't we cash in that original investment by using the bulb until it's
worn out?
But the economic answer is clear:
{\em{continuing to use an old lightbulb is throwing good money after bad}}.
If you can find a satisfactory low-energy replacement, replace the old bulb {{now}}.
}
%More bulb options, on black backgrounds mainly
%
%Bulbs11bb.jpg.eps
%Bulbs11bc.jpg.eps
%Bulbs20a.jpg.eps
%Bulbs6011b.jpg.eps
%Bulbs6011c.jpg.eps
%Bulbs6011d2.jpg.eps
%Bulbs6011e2.jpg.eps
%Bulbs6011.jpg.eps
%Bulbs6020a.jpg.eps
%Bulbs6020b.jpg.eps
%Bulbs6020c.jpg.eps
%Bulbs6020d.jpg.eps
%Bulbs60bb.jpg.eps
%Bulbs60cc.jpg.eps
%
%
\qa{What about the \ind{mercury} in compact fluorescent lights?
Are LED bulbs better than\index{bulb!LED}\index{lightbulb!LED}
fluorescents?}{
Researchers%
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\epsfxsize=53mm\epsfbox{../../images/LEDBulb.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
Philips 11\,W alongside
Omicron 1.3\,W LED bulb.
}\label{PhilOm}
}
say that LED (light-emitting diode)
bulbs will soon be even more energy-efficient than
compact fluorescent lights. The efficiency of a light
is measured in {\dem\ind{lumens per watt}}.
I checked the numbers on my latest purchases:
the Philips Genie 11\,W compact fluorescent
bulb (\figref{PhilOm}) has a brightness of 600 lumens,
which is an efficiency of {\bf{55 lumens per watt}};
regular incandescent bulbs deliver {\bf{10 lumens per watt}};
the Omicron 1.3\,W lamp, which has 20 white LEDs
hiding inside it, has a brightness of 46 lumens,
which is an efficiency of {\bf{35 lumens per watt}}.
So this LED bulb is almost as efficient as the fluorescent bulb.
The LED industry still has a little catching up to do.
In its favour, the LED \ind{bulb}\index{lightbulb} has a life
of 50\,000\,hours,
eight times the life of the \ind{fluorescent bulb}.
As I write, I see that
\myurl{www.cree.com} is selling LEDs with a power of
{\bf{100 \ind{lumens per watt}}}.
It's projected that in the future, white LEDs will have an efficiency
of over 150\,\ind{lumens per watt}
\tinyurl{ynjzej}{http://www.aceee.org/conf/06modeling/azevado.pdf}.
I expect that within another couple of years, the best advice, from the
point of view of both \ind{energy efficiency} and avoiding \ind{mercury} \ind{pollution},
will be to use \ind{LED} bulbs.%
}
%% *** I stole figure and table from here and put them in the notes of lighting
\subsection{Mythconceptions}
\beforeqa
\qa{``There is no point in my switching to energy-saving lights.
The ``wasted'' energy they put out heats my home,
so it's not wasted.''}{
This myth is addressed in Chapter \ref{ch.gadget}, \pref{pMythLight}.
}
% IDEA to save space -- exhcange this myth location
%\pagebreak[4]
\small
\section{Notes and further reading}
\nopagebreak
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pStreetL}]
{\nqs{
Street-lights use about 0.1\,kWh per\index{street-light} day per person\ldots}
}
%
\margintab{
\begin{center}
\begin{tabular}{lr} \toprule
Bulb type & \makebox[0in][r]{efficiency}\\
& \makebox[0in][r]{(lumens/W)} \\ \midrule
incandescent & 10 \\% 10, 12, 17, 13
halogen & 16--24 \\% 9% efficient 16, 24
white LED & 35 \\
compact fluorescent & 55 \\
%% metal halide & 65--115 \\
large fluorescent & 94 \\% 45, 50, 60, 93, 104
% 40--100 \\ 45-104
sodium \makebox[0in][l]{street-light} & 150\\% 120--180 \\ %% 150-200 low rpessure sodium: 183-200
%% http://www.gelighting.com/eu/resources/firstlight/module03/05.html ``94''
%% http://www.lightingstyles.co.uk/Energy_Saving_Lighting.htm
% theoretical maximum , pure green -- 683 lm/W
\bottomrule
\end{tabular}
\end{center}
\caption[a]{Lighting efficiencies of commercially-available bulbs.\index{compact fluorescent light}\index{CFL}
In the future, white LEDs are expected to deliver 150 lumens per watt.
}
\label{tab.lumensW}
}
% {\sf Street-lights.}
% I would guess that t
There's roughly
% Street-lights:
one sodium \ind{street-light} per 10 people;
% five houses,
each light has a power of 100\,W, switched on
for 10 hours per day. That's 0.1\,kWh per day per person.
\item[\npageref{pStreetL2}]
{\nqs{ \ldots
and traffic lights only 0.005\,kWh/d per person.}
}
% {\sf Traffic lights.}
%% 27W per bulb on average
Britain has 420\,000 traffic\index{traffic lights}
and pedestrian signal light bulbs, consuming 100 million kWh of electricity per year.
% are currently responsible for almost 57\,000
% tonnes of carbon dioxide emissions thanks to the 100 million kWh of electricity they use each year. Currently the vast majority of the lights are of the standard incandescent type.''
%% http://www.reuk.co.uk/UK-Traffic-Lights-57000-Tonnes-Of-CO2.htm
% Let's personalize these data.
Shared between 60 million people,
100 million kWh
per year is 0.005\,kWh/d per person.
%% that's 4e-5 of our total energy consumption.
\item[\npageref{pfewerbollard}]
% energy saving trust say
% 4e6 double decker bus
% of CO2 is equivalent to
% 1 yr of UK streetlights
{\nqs{There are fewer signs and illuminated bollards than street-lights.}}
\newlineone
[\myurlb{www.highwayelectrical.org.uk}{http://www.highwayelectrical.org.uk/}].
There are 7.7\,million lighting units (street lighting,
illuminated signs and bollards) in the
\UK\@. Of these, roughly 7 million are street-lights
and 1 million are illuminated road signs.
There are 210\,000 traffic signals.
%% typical street-light is 100W
According to DUKES 2005, the total power for public lighting is 2095\,GWh/y,
which is 0.1\,kWh/d per person.
% 2095e6/60e6/365.25 ans = 0.095597
% http://www.lcpe.gov.uk/Library/Projects/Modernising_Energy_Procurement/PFC_Document%20Final%20Edition_10_11_06.pdf
%This document
%\tinyurl{2uetco}{http://www.lcpe.gov.uk/}
%says there are 700\,MW of street-lights (7 million at 100\,W each),
%on for 4200\,hours per year -- gives
%2.9e9 kWh/yr =
%0.13\,kWh/day/person.
% 7 million bulbs, which is roughly 1 between 10.
\item[\npageref{pAltern}]
{\nqs{ 55\%-efficient generator}}
-- source:
\newlineone
\myurlb{en.wikipedia.org/wiki/Alternator}{http://en.wikipedia.org/wiki/Alternator}. Generators in power stations are
much more efficient at converting mechanical work to electricity.
\end{notelist}
\normalsize
\gset\chapter{\gcol{Offshore wind}}
\label{ch.offshore}
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/640/nac_5S.jpg.eps}}%
{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/640/nac_5.jpg.eps}}\\
% \mbox{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/640/Aerial_Views_3.jpg.eps}}\\
\lowres{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/640/Windfarm_Site_002S.jpg.eps}}%
{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/640/Windfarm_Site_002.jpg.eps}}\\
\end{tabular}
\end{center}
\caption[a]{%
\ind{Kentish Flats} -- a shallow offshore {\windfarm}.
Each rotor has a diameter of 90\,m centred on a hub height of 70\,m.
Each ``3\,MW'' turbine weighs 500 \tonnes, half of which is its foundation.
% and most of the weight is steel
% the latest version of the V90 has a low top head mass (THM) of only 111 tonnes (nacelle 70 tonnes, rotor 41 tonnes),
% Three 33\,kV cables connect it to the shore.
% The intended lifetime is 20 years and
% the installation cost was \pounds 105 million.
% tower, nacelle and rotor = 218 tons each
% total steel in one windpark of 36 V90s in netherlands: 17500 tons = 486 t steel each
% http://www.we-at-sea.org/docs/BallastNedampresentation.pdf
Photos \copyright\ Elsam ({\tt{elsam.com}}). Used with permission.
}
\label{KFWFfig}
}
\myquote{%
The London Array offshore {\windfarm} will make a crucial contribution to the UK's renewable energy targets.
% Offshore wind will be a very important part of the development of renewable energy
}{
James Smith, chairman of \ind{Shell UK}\index{Smith, James}
% Gordon Brown
% http://www.parliament.the-stationery-office.co.uk/pa/cm200708/cmhansrd/cm080206/debtext/80206-0003.htm
}
\myquote{Electric power is too vital a
commodity to be used as a job-creation programme for the wind
turbine industry.
}{\index{White, David J.}{David J.\ White}
% July 2004 The utilities journal
}
\index{wind!offshore}\index{offshore wind}At sea, winds are stronger
and steadier than on land, so offshore {\windfarm}s deliver a higher
power per unit area than onshore {\windfarm}s. The
\ind{Kentish Flats} {\windfarm} in the Thames Estuary,\label{KFWF}
about 8.5\,km offshore from \ind{Whitstable} and \ind{Herne Bay},
which started operation at the end of 2005,
was predicted to have an average power per unit area of 3.2\,\Wmm. In 2006,
its average power per unit area was 2.6\,\Wmm.
% http://www.ref.org.uk/Pages/4/uk_renewable_energy_data.html
% 8 December 2005.
%% see wind2.tex for link to actual data on these.
%20-year lifetime.
%Expected annual output 280\,GWh, i.e., 32\,MW, i.e. capacity factor of 0.36.
%% http://news.bbc.co.uk/1/hi/england/kent/6309013.stm
%% Of the 36 turbines erected off Herne Bay - on the Kentish Flats - 12 have experienced gearbox problems. (by Jan 2007)
%% News, 29 Jan 2007;
%% capital grant of 10 million pounds for
%% kentish flats.
%% If it produces 280GWh per year for 20 y then (ignoring inflation)
%% 10 million grant is 0.2p / kWh
%% pr 1000e6 / ( 280*20e6 )
%% 0.178571428571429
%% http://favores.die.unipd.it/Downloads/finalReports/wp4/4_B_WP4_Current_State_of_UK_Offshore_Wind.pdf
% 19 December 2006 ROC trading site's data
%% http://www.rocregister.ofgem.gov.uk/main.asp
% has been assimilated by
% http://www.ref.org.uk/energydata.php
% Kentish Flats appears as R00006RPEN (90MW) (30 turbines)
% on p12 of the pdf file.
% It was doing 33% in january 2006
% see also http://www.wind-farm.co.uk/load.xls
% http://www.wind-farm.co.uk/
% Kentish Flats (now owned by vattenfall not elsam) production was
% 2005: Oct Nov Dec (MWh)
% 20408 22435 21585 (which are capacities of 30.5, 34.6, 32.24
% http://www.clowd.org.uk/pages/clowdWindResource.htm
% Atual prodution in 2006
%^ R00006RPEN Kentish Flats Ltd - A,C 90 227279 788400 28.83
% source http://www.ref.org.uk/
I'll assume that a power
per unit area\index{power density!offshore wind}\index{wind!offshore!power density} of
% 3\,\MWkk or
\OliveGreen{3\,\Wmm}
(50\% larger than our onshore
estimate of 2\,\Wmm) is an appropriate figure for
offshore {\windfarm}s around the UK\@.
We now need an estimate of the area of sea
that could plausibly be covered with wind turbines.
It is conventional to distinguish between {\em{shallow}\/} offshore wind and
{\em{deep}\/} offshore wind, as illustrated in \figref{fig.Z25}.\index{offshore wind!shallow}\index{shallow offshore wind}
Conventional wisdom\label{pWindOffshore} seems to be that
{\em{shallow}\/} offshore wind (depth less than 25--30\,m),
while roughly twice as costly as land-based wind,
% (Source:
% Danish wind association
% windpower.org)
is economically feasible, given modest subsidy; and
{\em deep\/} \ind{offshore wind} is at present not
% at all
economically feasible.
% (Source: BWEA.)
As of 2008, there's just one \ind{deep offshore wind}farm in UK waters,\index{offshore wind!deep}
an experimental prototype sending all its electricity to
a nearby \ind{oilrig} called Beatrice.
% BEGIN fix white space crap
{
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
\begin{figure}
\figuremargin{
\begin{center}
%% PERMISSION GRANTED
%%The Crown copyright protected material (other than the Royal Arms and departmental or agency logos) may be reproduced free of charge in any format or medium - provided it is reproduced accurately and not in a misleading context.
%% http://www.berr.gov.uk/administration/copyright/index.html
%% To get high resolution version, switch to the second line
{\mbox{%
%\epsfxsize=4.7507995in% full textwidth
%\epsfxsize=77mm% *** Ask Niall if this quality good enough
%\epsfbox{../../refs/DTIAtlas/Z25.50e.pdf.jpg.eps}}}
%%\epsfbox{../../refs/DTIAtlas/Z25.50e.pdf.eps}}}
\lowres{%
\includegraphics[height=100mm]{../../refs/DTIAtlas/Z25.50eNEW.jpg.eps}
}{%
\includegraphics[height=100mm,clip=true,trim=52 51 35 42]{../../refs/DTIAtlas/Z25.50eNEW.ps}
}
}}
\end{center}
}{
\caption[a]{\ind{UK territorial waters} with depth less than 25\,m (\mono{light}{yellow})
and depth between 25\,m and 50\,m (\mono{dark}{purple}).\index{bathymetry}
Data from DTI Atlas of Renewable Marine Resources.\index{data!bathymetry}\index{data!water depths}\index{data!sea depths}\index{data!depths}\index{bathymetry}\index{water depths}\index{sea depths}\index{depths}
\copyright\ Crown copyright.
% \medskip \medskip \medskip \medskip \medskip \medskip \medskip \medskip
% \medskip \medskip \medskip \medskip \medskip \medskip \medskip \medskip
% \medskip \medskip \medskip
\medskip \medskip \medskip \medskip
\par
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/kentish.eps,angle=270}}
}
\label{fig.Z25}
}
\end{figure}
\section{Shallow offshore}
% \cite{DTIAtlas} Page 23 gives summary of resource availability.
Within British
% U.K.\
territorial waters, the {shallow} area
% (5--25\,m)
is
% The area of water with a depth less than 25\,m is
about 40\,000\,km$^2$, most of it off the
coast of England and \ind{Wales}.
%% see _wind.tex for excellent breakdown.
This area is
% about one sixth of the area of the United Kingdom
about two Waleses.
% 4 million km$^2$.
% The deep area (25--50\,m) is
% 3 million km$^2$. I don't buy that. It
% looks like 1 million to me on the map.
% Would deep wind have to be
% within say 30\,km of the coast for transmission to be feasible?
% apparently 8.5\km is fine.
% Outside UK territorial waters,
% there's a further 2.3 million km$^2$ of shallow
% and 3.8 million km$^2$ of deep.
%
% Offshore wind power
% From
% xpdf ../../refs/DTIDigest.pdf
%
% Offshore wind speeds are higher than those onshore (typically up to
% 0.5m/s higher 10 km offshore) and also less turbulent. However,
% elevated inland sites can have higher wind speeds.
% There's not much to say about offshore wind.
% We need an estimate of
% typical wind-speed, and
The average power available from
shallow offshore {\windfarm}s
% occupied a strip of width 10\,km the full length of the
% UK (1000\,km), then the power delivered would be
% 30\,000\,MW, that is, 30\,GW
occupying the whole of this area would be 120\,GW,
or 48\,kWh/d per person.
% WALES = 20700 km**2
% This maximum power could be delivered by planting
% turbines
% across an area in the North Sea the size of Wales,
% including the whole Thames estuary;
% some parts are as much as 200\,km offshore, so
%
But it's hard to imagine this arrangement being satisfactory for
shipping.
Substantial chunks of this shallow water
would, I'm sure, remain off-limits for {\windfarm}s.
% And would people living on the coast
The requirement for shipping corridors and fishing areas
% , and resistance to having turbines close to the shore,
must reduce the plausibly-available area;
I propose that we assume the available fraction is one
third (but please see this chapter's end-notes for
a more pessimistic view!).\nlabel{pessimOff}
So we estimate the
maximum plausible power from shallow offshore wind
to be \OliveGreen{16\,kWh/d per person}.
% 40\,GW
% 3000 * 4 = 12,000
Before moving on, I want to emphasize the
large area -- two thirds of a Wales --
that would be required to deliver this
16\,kWh/d per person.
If we take the total coastline of Britain (length: 3000\,km),\label{coastline}
and put a strip of turbines 4\,km wide all the way round,
that strip would have an area of
% Here's another way of thinking about the
13\,000\,km$^2$.
% area that we're trying to imagine filling with
That is the area we must fill with turbines to deliver 16\,kWh/d per person.
To put it another way, consider the number of turbines required.
16\,kWh/d per person would be delivered by 44\,000 ``3\,MW'' turbines, which
works out to 15 per kilometre of coastline, if they were evenly spaced
around 3000\,km of coast.
% It's also worth mentioning
% that o
Offshore wind is tough to pull off because of the corrosive effects of
sea water. At the big Danish {\windfarm}, \label{pHR}\ind{Horns Reef},
all 80 turbines had to be dismantled
and repaired after only 18 months' exposure to the sea air.
The Kentish Flats turbines seem to be having similar problems with
their gearboxes, one third needing replacement during
the first 18 months.
% 3000 * 25 = 75,000
\section{Deep offshore}
The area with depths between 25\,m and 50\,m is about
80\,000 km$^2$ -- the size of Scotland.\index{wind!deep offshore}
Assuming again a power per unit area of 3\,\Wmm,
``deep'' offshore {\windfarm}s could deliver another
240\,GW, or
96\,kWh/d per person, if turbines completely filled this area.
Again, we must make corridors for shipping.
I suggest as before that we assume we can use one
third of the area for {\windfarm}s;
this area would then be about 30\% bigger than
Wales, and much of it would be further than 50\,km offshore.
The outcome:
if an area equal to a
%% corrected 25km typo Thu 17/1/08
9\,km-wide strip all round the coast were filled with turbines,
deep offshore wind
could deliver a power of \OliveGreen{32\,kWh/d per person}.
%% 80 GW.
A huge amount of power, yes; but still no match for our huge consumption.
%% *** 'no match' disagrees with the fact that the green stack is looking good
And we haven't spoken about the issue of wind's
\ind{intermittency}. We'll come back to that in \chref{ch.storage}.
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{cc}
% {\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.30}} }\\
%\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.281}}}\\%30}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Offshore wind.}
\label{offshoreslabs}
}
% \end{figure}
% I've shown this potential deep offshore contribution in
% \figref{offshoreslabs}, but I don't think it is plausible that
% more than 2 or 3\,kWh per day per person will come from this
% source, so I won't include it in subsequent production stacks.
I'll include this potential deep offshore contribution
in the production stack, with the proviso, as I said
before, that wind experts reckon deep offshore wind
is prohibitively expensive.
% not economically feasible.
}
% END fix white space crap
\section{Some comparisons and costs}
So, how's our race between consumption and production
coming along? Adding both shallow and deep offshore wind to the production
stack, the green stack has a lead.
% it's neck and neck.
Something I'd like you to notice
about this race, though, is this contrast:
how {\em{easy}\/} it is to toss a bigger log
on the consumption fire, and how {\em{difficult}\/} it is to grow
the production stack.
As I write this paragraph, I'm feeling a little cold, so I step
over to my thermostat and turn it up. It's so simple for me
to consume an extra 30\,kWh per day.
But squeezing an extra 30\,kWh per day per person from renewables
requires an industrialization of the environment so
large it is hard to imagine.
% 4 kWh/d <-> 10 GWav <-> 5 million tonnes of concrete and steel
% 48 kWh/d <-> 120 GWav <-> 60 million tonnes of concrete and steel
To create 48\,kWh per day of offshore wind per person in the UK would
require \conccol{60 million \tonnes\ of concrete and steel} --
one \tonne\ per person.
Annual world \ind{steel production} is about 1200\,million \tonnes,
which is 0.2 \tonnes\ per person in the world.
During the second world war, American shipyards built 2751
Liberty ships,\nlabel{pLiberty}
% The construction of one Liberty ship required 3,425 tons of hull steel, 2,725 tons of plate, and 700 tons of shapes, which included 50,000 castings.
% http://www.liberty-ship.com/html/yards/introduction.html
% in 4 or 5 years
% 6850
% On the average, it took 592,000 man-hours to build a Liberty Ship.
each containing 7000 \tons\ of steel -- that's a total of 19 million \tonnes\ of steel,
or 0.1 \tons\ per American.
So the building of 60 million \tonnes\ of wind turbines is not
off the scale of achievability; but don't kid yourself into thinking
that it's easy. Making this many windmills is as big a feat as building the
Liberty ships.
%% SHOULD ADD A NOTE HERE TOO
%% see {pNukeCOO} in nuclearnotes.tex Need 120GW
% per GW: of concrete (1.2 million \tons) and
% 67\,000 \tonnes\ of steel
% comes to 144 Mt of concrete and 8 Mt of steel
For comparison, to make
48\,kWh per day of nuclear power per person in the UK would require
\conccol{8 million \tonnes\ of steel} and \conccol{140 million \tonnes\ of concrete}.
We can also compare the 60 million \tonnes\ of offshore wind hardware
that we're trying to imagine with the existing fossil-fuel hardware
already sitting in and around the North Sea (\figref{Magnus}).
% rig count http://www.bakerhughes.com/investor/rig/rig_int.htm
% says the offshore count in UK is 14 or 26
% oil rig googles....
% 43 000 tonnes of steel, 12000,
% 2.6 million tonnes of steel from the 400 installations in the North Sea alone.
% Four hundred oil and gas installations in the North Sea contain
% 2.6 million tonnes of steel.
% In 1996 there were at least 10 million tonnes of steel in
% rigs and pipes. (according to New Scientist quote of Lords)
% Decommissioning the Brent Spar
% By Paula Owen
% says total weight of 8 million tonnes in 200 UK structures and 7000 km of pipelines
In 1997, 200 installations
and 7000\,km
of pipelines in the UK waters of the North Sea
contained \conccol{8 million \tonnes\ of steel and concrete}\label{pBrentSpar}.
% http://archive.greenpeace.org/comms/toxics/dumping/jun20.html
The newly built \ind{Langeled} \ind{gas pipeline} from Norway to Britain,
which will convey gas with a power of 25\,GW (10\,kWh/d/p),
% (thermal),
used another \conccol{1 million \tonnes\ of steel} and \conccol{1 million \tonnes\
of concrete} (\figref{langpipe}).
% monsters: The hibernia platform off newfoundland weighs 1.2 million tons, much of it ballast presumably.
% deaths: piper alpha 1988: 167 Alexander Kielland capsize 1980: 123
% In British waters, the cost of removing all platform rig structures entirely was estimated in 1995 at $345 billion
% brent spar: 14 500-tonne North Sea oil platform, includes 6800 tonnes of hematite mixed with concrete Ballast
% BRENT SPAR = 6700 tonnes of high-grade steel, 28 tonnes of aluminium, 15 tonnes of zinc and 15 tonnes of copper.
% The British sector of the North Sea contains more than 200 rigs and an estimated 10 000 kilometres of pipes. In a report published in March, the Lords science and technology committee said that some 10 million tonnes of steel could be brought ashore in the next few years, with a market value of around £3 billion.
% From issue 2058 of New Scientist magazine, 30 November 1996, page 26
% http://environment.newscientist.com/channel/earth/energy-fuels/mg15220584.700
% http://www.parliament.uk/post/pn065.pdf
% says Brent Spar = 7000 t concrete and iron ore (haemetite); and 7500 t steel.
% says cleaning up all the north sea stuff including pipelines would cost 3 billion pounds (1995)
% typical oil platform:
% http://www.planete-energies.com/content/features/oil-rig/figures.html
% Weight: 43 000 tonnes of steel
% Cost: 2.25 billion euros
% Production: 40 000 barrels per day
% Alwyn North, in depth of 126 m
% section{ financial costs }
% \tinyurl{2ebj6p}{http://news.bbc.co.uk/1/hi/uk/3063433.stm} 2003 announcement of 7GW?
The UK government announced on 10th December 2007\label{GW33}
% http://www.guardian.co.uk/environment/2007/dec/10/politics
that it would permit the creation of 33\,GW
of offshore wind capacity (which would deliver on average 10\,GW to the UK,
or 4.4\,kWh per day per person),
a plan branded ``pie in the sky'' by some in the wind industry\nlabel{pPie}.
% \tinyurl{2t2vjq}{http://www.guardian.co.uk/environment/2007/dec/11/windpower.renewableenergy}.
%% Dan Lewis: "The government is deluding itself on a grand scale. There will be no race by investors to build offshore {\windfarm}s - the returns are just not high enough and there are supply-chain constraints in installation vessel capability and insufficient turbines."
%"Thirty-three gigawatts by 2020 is pie in the sky," said Gordon Edge of the British Wind Energy Association. "We think 20GW is ambitious but achievable."
% For a moment,
Let's run with a round figure
% one quarter of my 16\,kWh per day:
of 4\,kWh per day per person.
%% , and muse on its implications.
% This is the same as 10\,GW
% per \UK\ on average, and it's
This is one quarter of my shallow 16\,kWh per day per person.
To obtain this average power
requires roughly 10\,000 ``3\,MW'' wind turbines
like those in \figref{KFWFfig}.
(They have a capacity of ``3\,MW'' but on average they deliver 1\,MW\@.
I pop quotes round ``3\,MW'' to indicate that this is a \ind{capacity}, a
\ind{peak power}.)
% This is roughly double the amount of \UK\ wind power
% that the government planned for 2010.
%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\epsfxsize=50mm\epsfbox{../../images/MagnusAbseilers.eps}}\\
{\epsfxsize=50mm\epsfbox{../../images/TerryCavnerRig.eps}}\\
\end{tabular}
\end{center}
\caption[a]{
The \ind{Magnus platform}
in the northern UK sector of the North Sea
% has a 40\,000 ton steel jacket and the topsides weigh 31,000. (mainly steel)
contains 71\,000 \tons\ of steel.
% production of 55,000 bpd
% development cost was 1.1 billion pounds
% http://www.bp.com/liveassets/bp_internet/globalbp/STAGING/global_assets/downloads/U/uk_asset_magnus.pdf
% For many years it was BP's single biggest asset.
%During 2000, Magnus produced and exported 3.78
%million tonnes of oil and gas. This represents a
%reduction on hydrocarbons produced during 1999 (4.1
%million tonnes).
%The amount of gas flared from Magnus during 2000
%totalled 8.7 million m3, with an average of 23,764 m3/day
%The amount of fuel gas used on the Platform for power
%generation amounted to 97,271 tonnes for the year 2000. In
%addition 2,114 tonnes of diesel was also used.
% http://www.bp.com/liveassets/bp_internet/globalbp/STAGING/global_assets/downloads/V/verfied_site_reports/Europe/magnus_e_of_Shetland_2000.pdf
%The major source of carbon dioxide on Magnus is
%however due to burning fuel gas for power generation in
%the main gas turbines.
% total in 2000:
% 286,000 tonnes of CO2 from flaring and from burning gas in turbines.
In the year 2000 this platform delivered
3.8 million \tonnes\ of oil and gas --
a power of 5\,GW\@.
% or perhaps 6GW, depending on the oil/gas mix
% The power to run the platform
% was 160\,MW.
The
% development
platform cost \pounds1.1 billion.
% 99.3e6 * 50208000 / ( 365*24*3600 )
%The Magnus jacket is the largest single piece
%steel structure yet to be designed and
%constructed for the North Sea. (in document dated 2003)
\par
Photos by Terry Cavner.
% permission granted Wed 2/1/08
% *** express the power output of magnus in windturbines
}
\label{Magnus}
}
%
\marginfig{
\begin{center}
\mbox{\epsfxsize=50mm\epsfbox{../../images/langeledPipes.jpg.eps}}\\
\end{center}
\caption[a]{
Pipes for \ind{Langeled}.
From Bredero--Shaw
{[\myurlb{brederoshaw.com}{http://brederoshaw.com/}]}.
}
\label{langpipe}
}
% How long would it take to erect 10\,000 wind turbines?
% One of the bottlenecks is the ships required. Say 60 appropriate
% days per year, and 60 ships, and one turbine per day per ship:
% three years.
% There aren't 60 jack-up ships? Well, surely we can build them.
% http://news.bbc.co.uk/1/hi/magazine/7206780.stm
% An appropriate Jack-up barge costs \pounds 60 million
% It takes 3 days to do foundations and 1 day to put turbine.
%\subsection{Economic cost}
What would this ``33\,GW'''
of power cost to erect?\nlabel{phowmuchoff} Well, the ``90\,MW''
% 32\,MW
%% they call it 90 MW (30 x 3MW) peak
Kentish Flats farm cost \pounds 105 million,
so ``33\,GW'' would cost about \pounds 33 billion.
%
% , or \pounds 550 per person.
One way to clarify this
\pounds 33 billion cost of offshore wind delivering 4\,kWh/d per person
is to share it among the UK population; that comes
out to \pounds 550 per person. This is a much better deal, incidentally,
than \ind{micro-turbine}s. A roof-mounted micro-turbine currently costs\index{micro-wind}\index{micro-generation}\index{decentralization!micro-turbines}
about \pounds 1500 and, even at a very optimistic
windspeed of 6\,m/s, delivers only 1.6\,kWh/d.\index{wind!micro-wind}
In reality, in a typical urban location in England,
such micro-turbines deliver 0.2\,kWh per day.\nlabel{pMicrW}
Another bottleneck constraining the planting of wind turbines is the special
ships required.
To erect 10\,000 wind turbines
(``33\,GW'')
over a period of 10 years
would require roughly 50 \ind{jack-up barge}s.
% 5 years * 60 working days per year * N ships / 4 days per turbine
% N = 10000 * 4 / 300 = 133.
These cost \pounds60 million each,\nlabel{pJackUp} so an extra
capital investment of \pounds3 billion would be required. Not a show-stopper
compared with the \pounds33\bn\ price tag already quoted,
but the need for \ind{jack-up barge}s is
certainly a detail that requires some forward planning.\index{offshore wind!jack-up barges}\index{wind!offshore!jack-up barges}
\subsection{Costs to birds}
%% {A bird in the hand is worth two in the bush}
% I've never quite understood the value of having a bird
% on one's hand -- it sounds dangerous for the hand and distressing
% for the bird.
% But it's a saying with numbers and birds, and that's what this
% section is about.
Do windmills kill ``huge numbers'' of birds?\index{birds and windmills}
{\Windfarm}s recently got adverse publicity from \ind{Norway}, where
the wind turbines on \ind{Smola}, a set of islands off the north-west coast,
killed 9 \ind{white-tailed eagles} in 10 months.
% www.rspb.org/policy/windfarms/eaglestrike.asp
% www.birdlife.org/news/news/2006/02/norway.html
I share the concern of BirdLife International for the welfare
of rare birds.
But I think, as always, it's important to do the numbers.
It's been estimated that
% From \citep{Lomborg2001}, we find estimates that
30\,000 birds per
year are killed by wind turbines in Denmark, where windmills generate
19\% of the electricity.
%% see errata
Horror! Ban windmills!
We also learn, moreover, that {\em traffic\/} kills {\em{one million}\/}
birds per year in \ind{Denmark}. Thirty-times-greater horror!
Thirty-times-greater incentive to ban cars!
And in Britain, 55 million birds per year are killed by
{\em cats\/} (\figref{fig.Birds}).\index{cat}
% for windows, see
% http://news.bbc.co.uk/cbbcnews/hi/animals/newsid_3513000/3513872.stm
% \tinyurl{32dv8q}{http://news.bbc.co.uk/1/hi/sci/tech/3505256.stm}
% which estimates 33 million deaths per year from windows.
\begin{figure}\figuremargin{
\begin{center}
\mbox{\epsfbox{metapost/sign.333}}
\end{center}
}{
\caption[a]{Birds lost in action.
Annual bird deaths in Denmark caused by
wind turbines and cars,
and annual bird deaths in Britain caused by
cats.
Numbers from \protect\citet{Lomborg2001}.
Collisions with windows kill a similar number
to cats.
}
\label{fig.Birds}
}
\end{figure}
% Average no of migratory birds that fly
% across the north sea: 80 million
% from North Sea Foundation, Wadden Sea Society
Going on emotions alone, I would like to live in a country with
virtually no cars, virtually no windmills, and with plenty of cats
and birds (with the
cats that prey on birds perhaps
being preyed upon by Norwegian white-tailed \ind{eagle}s, to even things up).
But what I really hope is that decisions about cars and windmills are
made by careful rational thought, not by emotions alone.
Maybe we do need the windmills!
%
%\label{Beatrice2}
%\medskip
%\beginfullpagewidth
\vfillone
\pagebreak[4]
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{KFWF}]
{\nqs{The \ind{Kentish Flats} {\windfarm} in the \ind{Thames Estuary}\ldots}}
\par
See \myurlb{www.kentishflats.co.uk}{http://www.kentishflats.co.uk/}.
% www.kentishflats.co.uk
Its 30 \ind{Vestas} V90 wind turbines have a total peak output of 90\,MW, and
the predicted average output was 32\,MW (assuming a \ind{load factor} of 36\%).
%
The mean wind speed at the hub height is 8.7\,m/s.
The turbines stand in 5\,m-deep water,\index{data!offshore wind}
are spaced 700\,m apart, and occupy an area of
10\,km$^2$.\index{offshore wind!data}
The power per unit area of this
offshore {\windfarm} was thus predicted to be 3.2\,\Wmm.
% \MWkk.
In fact, the average output was 26\,MW, so
the average load factor in 2006 was 29\%
% (227\,279\,MWh delivered, compared with a capacity of 8760 $\times$ 90\,MWh)
% (227\,GWh were delivered)
\tinyurl{wbd8o}{http://www.ref.org.uk/energydata.php}.
This works out to a power per unit area of 2.6\,\Wmm.
% North Hoyle had 36%. 188151 MWh out of 60MW 35.8%
% what is its Wmm?
% It has 30 V80 Vestas (2MW)
% http://www.reuk.co.uk/North-Hoyle-Offshore-Wind-Farm.htm
% says 10 sq km
% but it is 8.64 km**2
The \ind{North Hoyle} {\windfarm} off \ind{Prestatyn}, North \ind{Wales},
had a higher load factor of 36\% in 2006.
Its thirty 2\,MW turbines occupy 8.4\,km$^2$. They thus had an average
power per unit area of 2.6\,\Wmm.
% 2.56
% 350m by 800m rectangle for each of them
\item[\npageref{pWindOffshore}]
{\nqs{\ldots {shallow} offshore wind,
while roughly twice as costly as onshore wind,
is economically feasible, given modest subsidy}.}
Source: Danish wind association
\myurlb{windpower.org}{http://windpower.org/}.
\item[\npageref{pWindOffshore}]
{\nqs{\ldots {deep} offshore wind is at present not
economically feasible}.}\index{offshore wind}
Source: British Wind Energy Association
briefing document, September 2005, \myurlb{www.bwea.com}{http://www.bwea.com/}.
%
% SHALLOW means less than 30\,m.
% Not economically viable to go deeper than this, according to
% BWEA offshore briefing document, September 2005, www.bwea.com.
%
Nevertheless, a deep offshore demonstration project in 2007
put two turbines adjacent to the \ind{Beatrice} \ind{oil field}, 22\,km off the east coast
of \ind{Scotland} (\figref{Beatrice}).
Each turbine has a ``capacity'' of 5\,MW and sits in a water
depth of 45\,m. Hub height: 107\,m; diameter 126\,m.
% raw data http://www.rocregister.ofgem.gov.uk/main.asp
% Turbine weight 410\,tons, tower weight 210\,tons.
% 88+19
%% http://www.beatricewind.co.uk/Uploads/Downloads/Scoping_doc.pdf
All the electricity generated will be used by the \ind{oil platform}s.
Isn't that special!
The 10\,MW project cost \pounds30\,million -- this price-tag of
\pounds3 per watt (peak) can be compared with that of Kentish Flats,
\pounds 1.2 per watt (\pounds 105 million for 90\,MW).
\myurlb{www.beatricewind.co.uk}{http://www.beatricewind.co.uk/}
It's possible that {\em{floating}\/} wind turbines may change
the economics of deep offshore wind.
\item[\npageref{pessimOff}]
% was ... {DTIestOff}]
{\nqs{The area available for offshore wind.}}
The {Department of Trade and Industry}'s (2002) document
``Future Offshore''\nocite{FutureOffshore}
gives a detailed breakdown of areas that are useful for offshore wind power.
% , useful Capacity to contribution ratios.
%Shallow water (5--30\m) area of $27\,000\,\km^2$.
%Deeper water (30--50\m) area of $50\,000\,\km^2$.
\Tabref{TABWaters} shows the estimated resource in 76\,000\,$\km^2$ of shallow
and deep water.
The DTI's estimated power contribution, if these areas
were {\em entirely\/} filled with windmills,
% is $3\,200\,\TWh/\y$, which
is 146\,\kWh/d per person
(consisting of 52\,kWh/d/p from the shallow and 94\,kWh/d/p from the deep).
% see _wind.tex
But {{the DTI's estimate of the potential offshore
wind generation resource is just \OliveGreen{4.6\,kWh per day per person}}}.
\begin{table}[btp]
\figuremargin{
\begin{tabular}{lrrr@{\ }rrr} \toprule
&\multicolumn{2}{c}{depth 5 to 30 metres }&&
\multicolumn{3}{c}{depth 30 to 50 metres}\\ \cmidrule(r){2-3}\cmidrule(l){5-7}
Region & & potential &&& & potential \\
& \raisebox{7pt}[0pt]{area\ } & resource &&& \raisebox{7pt}[0pt]{area\ } & resource \\
&(km$^2$) & (kWh/d/p) &&& (km$^2$) & (kWh/d/p) \\ \midrule
% All waters
North West & 3\,300 & 6 &&& 2\,000 & 4 \\
Greater Wash & 7\,400 & 14 &&& 950 & 2 \\
Thames Estuary & 2\,100 & 4 &&& 850 & 2 \\
Other & 14\,000 & 28 &&& 45\,000 & 87 \\ \midrule
TOTAL & 27\,000 & 52 &&& 49\,000 & 94 \\ \bottomrule
%% original data were in TWh/y; I converted. original data in _offshore
%% 6.3883 14.1456 4.0155 27.6523 52.2017 3.9699 1.8252 1.5971 87.0180 94.4102
%% in kWh/d/p
\end{tabular}
}{
\caption[a]{Potential offshore wind
generation resource in proposed strategic regions,
if these regions were {\em{entirely filled}\/} with wind turbines.
From
% Table 2.2 in
{\protect\cite{FutureOffshore}}.
}\label{TABWaters}
}
\end{table}
It might be interesting to describe how they get down from this potential resource
of
% 3000\,TWh per year (
146\,kWh/d per person to
% 100\,TWh per year (
4.6\,kWh/d per person.
Why a final figure so much lower than ours?
First, they imposed these limits: the
water must be within 30\,km of the shore and less than 40\,m deep;
the sea bed must not have gradient
greater than 5\degrees; shipping lanes, military zones,
pipelines, fishing grounds, and wildlife reserves are excluded.
Second, they assumed
that only 5\% of potential sites will be
developed (as a result of seabed composition or planning
constraints);
they reduced
the capacity by 50\% for all sites less than
10 miles from shore, for reasons of public acceptability;
they further reduced the capacity of sites with wind speed over 9\,m/s
by 95\% to account for ``development barriers presented by the hostile environment;''
and other sites with average
wind speed 8--9\,m/s had their capacities reduced by 5\%.
\item[\npageref{coastline}]
{\nqs{\ldots if we take the total coastline of Britain (length: 3000\,km),
and put a strip of turbines 4\,km wide all the way round\ldots}}
\index{pedant}Pedants will say that ``the \ind{coastline} of Britain is not a well-defined
length, because the coast is
% (famously)
a \ind{fractal}.'' Yes, yes, it's
a fractal. But, dear \ind{pedant}, please take a map and put a strip of turbines
4\,km wide around mainland Britain, and see if it's not the case
that your strip is indeed about 3000\,km long.
% (to one decimal place).
\item[\npageref{pHR}]
{\nqs{\ind{Horns Reef}}} (Horns Rev).
The difficulties
with this ``160\,MW'' Danish {\windfarm} off \ind{Jutland}
[\myurlb{www.hornsrev.dk}{http://www.hornsrev.dk/}]
are described by \citet{Halkema}.
% \myurl{halkema-windenergyfactfiction.pdf}
% source - the dutch wind paper
% and http://www.earthscan.co.uk/news/article/mps/uan/485/v/3/sp/
When it is in working order, Horns Reef's \ind{load factor} is 0.43
and its average power per unit area is
2.6\,\Wmm.
\item[\npageref{pLiberty}]
{\nqs{Liberty ships}} --
\par
\myurlb{www.liberty-ship.com/html/yards/introduction.html}{http://www.liberty-ship.com/html/yards/introduction.html}
\item[\npageref{pBrentSpar}]
{\nqs{\ldots fossil fuel installations in the North Sea
contained 8 million tons of steel and concrete}} -- \cite{BrentSpar}.
\item[\npageref{GW33}]
{\nqs{The UK government announced on 10th December 2007
that it would permit the creation of 33\,GW
of offshore capacity\ldots}}
% 33\,GW peak announced by John Hutton
\tinyurlb{25e59w}{http://news.bbc.co.uk/1/low/uk_politics/7135299.stm}.
\item[\npageref{pPie}]
{\nqs{\ldots\ ``pie in the sky''}}.
Source: Guardian \tinyurl{2t2vjq}{http://www.guardian.co.uk/environment/2007/dec/11/windpower.renewableenergy}.
%
\marginfig{
\begin{center}
\lowres{ \begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=50mm\epsfbox{../../images/BeatriceBaseS.jpg.eps}}\\
% \mbox{\epsfxsize=50mm\epsfbox{../../images/Beatrice1S.jpg.eps}}\\
\mbox{\epsfxsize=50mm\epsfbox{../../images/Beatrice0S.jpg.eps}}\\
{\epsfxsize=50mm\epsfbox{../../images/Beatrice4S.jpg.eps}}\\%
{\epsfxsize=50mm\epsfbox{../../images/Beatrice6S.jpg.eps}}\\%
\end{tabular}
}{
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=50mm\epsfbox{../../images/BeatriceBaseCORR.jpg.eps}}\\
% \mbox{\epsfxsize=50mm\epsfbox{../../images/Beatrice1.jpg.eps}}\\
\mbox{\epsfxsize=50mm\epsfbox{../../images/Beatrice0.jpg.eps}}\\
{\epsfxsize=50mm\epsfbox{../../images/Beatrice4.jpg.eps}}\\
{\epsfxsize=50mm\epsfbox{../../images/Beatrice6.jpg.eps}}\\
\end{tabular}
}
%% \mbox{\epsfxsize=50mm\epsfbox{../../images/Beatrice3.jpg.eps}}\\ putting the base in
\end{center}
\caption[a]{
Construction of the \ind{Beatrice} demonstrator \ind{deep offshore wind}farm.\index{wind!deep offshore}
%
Photos kindly provided by
Talisman Energy (UK) Limited.
% {\myurl{http://www.beatricewind.co.uk/press/}}.
}
\label{Beatrice}
}%
\item[\npageref{phowmuchoff}]
{\nqs{What would ``33\,GW'' of offshore wind cost?}}
According to the DTI in November 2002, electricity from offshore {\windfarm}s
costs about \pounds50 per MWh (5p per kWh)
\cite[p21]{FutureOffshore}.
%% from futureoffshore
\index{economics}Economic facts vary,
however,\index{offshore wind!cost}\index{cost!offshore wind}
and in April 2007 the estimated cost of offshore\index{wind!offshore!cost}
was up to \pounds92 per MWh
\cite[p7]{OffshoreUpdate}.
By April 2008, the price of offshore
wind evidently went even higher:\index{wind!offshore!London Array}
\ind{Shell} pulled out of their commitment to build the \ind{London Array}.
It's because offshore wind is so expensive that the Government
is having to increase the number of
ROCs (\ind{renewable obligation certificate}s) per unit of offshore wind energy.
The ROC
is the unit of subsidy given out to certain forms of renewable
electricity generation.
The standard value of a ROC is \pounds45, with
1 ROC per MWh; so with a
wholesale price of roughly \pounds 40/MWh,
renewable generators are getting
paid \pounds 85 per MWh. So 1 ROC per MWh is not enough subsidy to cover the cost
of \pounds 92 per MWh.
% p7
In the same document, estimates for other renewables (medium levelized costs in
2010) are
as follows.
Onshore wind: \pounds65--89/MWh;
% offshore wind: \pounds92 per MWh
co-firing of biomass: \pounds 53/MWh;
large-scale hydro: \pounds 63/MWh;
sewage gas: \pounds 38/MWh;
solar PV: \pounds 571/MWh;
wave: \pounds 196/MWh;
tide: \pounds 177/MWh.
% interesting to read the wind lobby complaining and criticising
``Dale Vince, chief executive of green energy provider
Ecotricity, which is engaged in building onshore {\windfarm}s,
said that he supported the Government's [offshore wind]
plans, but only if they are not to the detriment of onshore wind.
% don't change thi squote mark
`It's dangerous to overlook the fantastic resource we have in this country\ldots\
% enough onshore wind to power the country three of four times over, enough
% to easily reach our target and at no extra cost," he said. "
By our estimates, it will cost somewhere in the region of \pounds40bn
to build the 33\,GW of offshore power Hutton is proposing.
We could do the same job onshore for \pounds20bn{'}.''\index{wind!cost}\index{offshore wind!cost}\index{cost!wind}
\tinyurl{57984r}{http://www.businessgreen.com/business-green/news/2205496/critics-question-government}
\item[\npageref{pMicrW}]
{\nqs{In a typical urban location in England,
micro-turbines deliver 0.2\,kWh per day}}.\label{pmicrowind}
Source: {\tem{Third Interim Report}},
\myurlb{www.warwickwindtrials.org.uk/2.html}{http://www.warwickwindtrials.org.uk/2.html}.
Among the best results in the Warwick Wind Trials study
% of thirty sites
% I think it is 2nd best; the best is Park Farm 0.652 kWh/d
% also check Misty Farm
is a {Windsave WS1000} (a 1-kW machine)
in Daventry mounted at a height of 15\,m
above the ground, generating 0.6\,kWh/d on average.
% 0.614
But some micro-turbines deliver only 0.05\,kWh per day --
Source:\index{McCarthy, Donnachadh}\index{wind!micro-wind}
Donnachadh McCarthy: ``My carbon-free year,'' {\em{The \ind{Independent}}},
December 2007
\tinyurl{6oc3ja}{http://www.independent.co.uk/environment/green-living/ donnachadh-mccarthy-my-carbonfree-year-767115.html}.
The \ind{Windsave WS1000} wind turbine, sold across England
in \ind{B\&Q}'s shops, won an
% *** GET PICTURE
\ind{Eco-Bollocks award} from {\tem{\ind{Housebuilder's Bible}}\/} author
Mark Brinkley:\index{Brinkley, Mark}
``Come on, it's time to admit that the roof-mounted
wind turbine industry is a complete fiasco.
%% CUTTABLE - next two sentences
Good money is being thrown at an invention that doesn't
work. This is the \ind{Sinclair C5}\index{C5} of the Noughties.''
\tinyurl{5soql2}{http://www.housebuildersupdate.co.uk/2006/12/eco-bollocks-award-windsave-ws1000.html}.
%
% policy
% http://www.carbontrust.co.uk/NR/rdonlyres/90EC40DE-7EA9-4D11-BE6F-62540CD9BA2A/0/10117_CT_Wind_Energy_v2.pdf
% facts
% http://www.carbontrust.co.uk/NR/rdonlyres/6A29EA3A-C9B1-4129-849A-554030DEA081/0/SmallscaleWindEnergyTechnicalReport.pdf
The Met Office and Carbon Trust published a report in July 2008
\tinyurl{6g2jm5}{http://www.carbontrust.co.uk/technology/technologyaccelerator/small-wind},
% At 10 metres,mean wind speed over most of SouthEastEngland is 9-10 knots
% which is 4.9 m/s
% page 135 estimates the resource
% 1.5kW turbine on a 3-metre mast above a house in west london
% predicted to produce 520 kWh/y (load factor 4%) . WHAT DIAMETER??
% page 159 list of devices
% summary: 15-20% capacity factor in english countryside
% suburban : 10%
% urban: few %
which estimates that,
% if every household in Britain had
% a 15-kW turbine on a 15-m pole (but in a rural location),
% the power generated would be 3.2\,kWh/d/p.
% 70.732 TWh/y / 60e6 in kWh/d
% In theory, small-scale wind energy has the potential to
% generate 41.3 TWh of electricity and save 17.8 MtCO2
%% - which is 1.9kWh/d/p
%% but at economic prices,
%% up to 1.5 TWh could be generated which is 0.07 kWh/d/p
%% scale up because their above number was
%% assuming 10% penetration. page 15 of 40
%% GRAPH shows 12 TWh/y which is 0.547
%% TABLE says 15 TWh/y which is 0.7
%% and if money no object (100p per kWh) then 37 TWh/y.
if small-scale turbines were installed at all
houses where economical in the UK, they would generate in total
roughly \OliveGreen{0.7\,kWh/d/p}.
% But they assumed the manufacturers' curves were correct which warwickwindtrials says is not so.
% and if economics were ignored, and every
% house had a turbine, they would generate
% \OliveGreen{1.9\,kWh/d/p}.
They advise that roof-mounted turbines in towns
are usually worse than useless:
``in many urban situations, roof-mounted turbines
may not pay back the carbon emitted during their
production, installation and operation.''
% exec summary page 4
% Real data from microturbines
% has been gathered at \myurl{www.warwickwindtrials.org.uk}.
% see also www.warwickwindtrials.org.uk/
% See _offshore.tex
\item[\npageref{pJackUp}]
{\nqs{\index{jack-up barge}{Jack-up barges} cost \pounds60 million each}.}
Source: \myurlb{news.bbc.co.uk/1/hi/magazine/7206780.stm}{http://news.bbc.co.uk/1/hi/magazine/7206780.stm}.
I estimated that we would need roughly 50 of them
by assuming that there would be 60 work-friendly days
each year, and that erecting a turbine would take 3 days.
\item[Further reading:]
UK wind energy database [\myurl{www.bwea.com/ukwed/}].
\end{notelist}
\normalsize
%\ENDfullpagewidth
\begin{figure}
\figuredangle{
%\marginfig{
\begin{center}
\begin{tabular}{@{}cc@{}}
\lowres{%
\mbox{\epsfysize=80mm\epsfbox{../../images/PUBLICDOMAIN/1000/Aerial_View_1s.jpg.eps}}}{%
\mbox{\epsfysize=80mm\epsfbox{../../images/PUBLICDOMAIN/1000/Aerial_View_1.jpg.eps}}}
&
\lowres{%
\mbox{\epsfysize=80mm\epsfbox{../../images/PUBLICDOMAIN/640/Windfarm_landview6.jpg.eps}}}{%
\mbox{\epsfysize=80mm\epsfbox{../../images/PUBLICDOMAIN/640/Windfarm_landview006.jpg.eps}}}
\\
% \mbox{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/640/Aerial_Views_2.jpg.eps}}\\ boring
% \mbox{\epsfysize=80mm\epsfbox{../../images/PUBLICDOMAIN/640/Aerial_Views_5.jpg.eps}}\\
% \mbox{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/640/Windfarm_landview020.jpg.eps}}\\ tiny
\end{tabular}
\end{center}
}{
\caption[a]{
\ind{Kentish Flats}.
Photos \copyright\ Elsam ({\tt{elsam.com}}). Used with permission.
}
}
\end{figure}
\normalsize
%\subsection{Check others}
% Open university page
%% http://images.google.co.uk/imgres?imgurl=http://openlearn.open.ac.uk/file.php/1697/220826-1f1.25.jpg&imgrefurl=http://openlearn.open.ac.uk/file.php/1697/formats/print.htm&h=304&w=456&sz=36&hl=en&start=7&um=1&tbnid=snzOqf4ssrwzRM:&tbnh=85&tbnw=128&prev=/images%3Fq%3Dhydro%2BScottish%2BHydro%2BElectric%26svnum%3D10%26um%3D1%26hl%3Den%26safe%3Doff%26client%3Dfirefox%26rls%3Dorg.mozilla:en-US:unofficial%26sa%3DN
% says 1200\,km$^2$ of ofshore would provide 10\% of UK electricity.
% Check: 10\% of UK elec is 4000\,MW, so they are saying a
% bit more than 3\,MW per km$^2$.
% Agreed.
% floating windmills
% http://www.sway.no/
% http://www.bluehgroup.com/
%
% gwynt y mor
% http://www.npower-renewables.com/gwyntymor/benefits.asp
% 268MW avg ie 36% load factor
% 2,350,000,000 kWh per year divided by the average annual electricity consumption of a UK household of 4,700 kWh per year = 500,000 homes.
% capacity 750 MW.
% in 94.8 km**2 or maybe just 79 km**2
% so was claiming 2.8 Wmm and is now 3.4 Wmm
\rset\chapter{\rcol{Gadgets}}%{Information systems}
\label{ch.gadget}
%% and other gadgets}
% Information devices and other gadgets.
% Standby power consumption currently accounts for 2.25% of electricity production
% source bluprint.pdf
One of the greatest dangers to
society is the \ind{phone charger}.
The \ind{BBC} News has been warning us of this since 2005:\label{bbcCharge}
\begin{quote}
``The \ind{nuclear power} stations will\index{keeping the lights on}
all be switched off in a few years. How can we keep Britain's lights on?
... {\bf{unplug your \ind{mobile-phone charger} when it's not in use}}.''
\end{quote}
Sadly, a year later, Britain hadn't got the message,
and the BBC was forced to report:
\begin{quote}
``{\bf{Britain tops \ind{energy waste league}}}.''
\end{quote}
% images/BritainStandby.png>
% I am on page 36 of mit doc
%
Geothermal
energy\index{geothermal energy}\index{energy!geothermal}
comes from two sources: from \ind{radioactive decay} in the \ind{crust} of the earth, and
from heat trickling through the mantle from the
earth's core. The heat in the core is there because
the earth used to be red-hot, and it's still
%% in the process of
cooling down and solidifying; the heat in the core is also being topped up
by \ind{tidal friction}: the earth flexes in response to the gravitational
fields of the \ind{moon} and \ind{sun}, in the same way that an \ind{orange} changes
shape if you squeeze it and roll it between your hands.
% see crosspad/sustainable/earth*ps
% for diagram.
%%% make earth
%\begin{figure}
% \figuremargin{
\marginfig{
\begin{center}
%\mbox{\epsfbox{crosspad/earth.ps}}
\mbox{\epsfbox{metapost/earth.20}}
\end{center}
%}{
\caption[a]{An earth in section.}
% , yesterday.}
%\end{figure}
}%
%
Geothermal is an attractive renewable because it is ``\ind{always on},''
independent of the weather; if we make geothermal power stations,
we can switch them on and off so as to follow demand.
\marginfig{
\begin{center}
\begin{tabular}{c}
\lowres{\epsfxsize=50mm\epsfbox{../../images/Granit2CS.jpg.eps}}%
{\epsfxsize=50mm\epsfbox{../../images/Granit2C.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
Some granite.
% , yesterday.
}
}
But how much geothermal power is available?
We could estimate \ind{geothermal power} of two types:
the power available at an ordinary location
on the earth's \ind{crust}; and the power available in special hot spots
like \ind{Iceland} (\figref{fig.IceBeau}).
While the right place to first develop geothermal
technology is definitely the special hot spots, I'm going to
assume that the greater total resource comes from the ordinary locations,
since ordinary locations are so much more numerous.
%originally
%Heat trickles through the mantle
%\marginfig{
\begin{figure}[tbp]
\figuremargin{
\begin{center}
\epsfxsize=\textwidth%
{\epsfbox{../../images/NesjavellirPowerPlant800.eps}}%
\end{center}
}{
\caption[a]{Geothermal power
in Iceland.
% , with hot steam transmitted
% to a steam turbine, generating electricity for
Average geothermal
electricity generation in \ind{Iceland} (population, 300\,000)
in 2006\index{data!Iceland}
was 300\,MW (24\,kWh/d per person).
More than half of Iceland's electricity is used for
\ind{aluminium} production.\index{Iceland}
% 2631e6/ (366) / 296737
% ans = 24
% 2631GWh/y. Iceland's population: 296,000. Iceland's electricity per person
% is 91.6 kWh/p/d.
% Of the total 9925 GWh generated in 2006,
% 5250 GWh was used in Aluminium.
% The industry in Iceland produces some 270kt of primary aluminium per annum.
%% In Iceland, there are five major geothermal power plants which produce about 26% (2006) of the country's electricity. In addition, geothermal heating meets the heating and hot water requirements for around 87% of the nation's housing.%% remainder of elec is from hydro
% LOWER: The Nesjavellir Geothermal Power Plant in Iceland
% produces 120MW of elec and 300 MW of heating water.
Photo
% s by Rosie Ward and
by \ind{Gretar \'Ivarsson}.
% , geologist at Nesjavellir
% stats from
% http://www.os.is/page/energystatistics
}\label{fig.IceBeau}
}
\end{figure}
The difficulty with making {\em{sustainable}\/} \ind{geothermal}
power is that the speed at which heat travels through solid rock limits
the rate at which heat can be sustainably sucked out of the red-hot interior
of the earth. It's like trying to drink a crushed-ice drink
through a \ind{straw}.
You stick in the straw, and suck, and you get a nice mouthful of
cold liquid. But after a little more sucking,
you find you're sucking air. You've extracted all the liquid from the ice
around the tip of the straw. Your initial rate of sucking wasn't sustainable.
If you stick a straw down a 15-km hole in the earth, you'll find
it's nice and hot there, easily hot enough to boil water.
So, you could stick two straws down, and pump cold water down one \ind{straw}
and suck from the other. You'll be sucking up steam, and you can
run a power station. Limitless power? No.
After a while, your sucking of heat out of the rock will
have reduced the temperature of the rock. You weren't sucking
sustainably. You now have a long wait
before the \ind{rock} at the tip of your straws warms up again.
A possible attitude to this problem is to
treat geothermal heat the same way we currently treat fossil fuels:
as a resource to be mined\index{mining!geothermal}\index{geothermal mining}
rather than collected sustainably.
Living off geothermal heat in this way might be better for the
planet than living unsustainably off fossil fuels; but
perhaps it would only be another \ind{stop-gap} giving us another 100 years
of unsustainable living?
In this book I'm most interested in {\em{sustainable}\/} energy,
as the title hinted.
% So let's first work out the sustainable power we could get from
% geothermal energy.
Let's do the sums.
\section{Geothermal power that would be sustainable forever}
First imagine using geothermal energy sustainably by
sticking down straws to an appropriate depth, and sucking {\em{gently}}.
Sucking at such a rate that the rocks at the end of the
our straws don't get colder and colder.
This means sucking at the natural rate at which heat is already
flowing out of the earth.
As I said before, geothermal energy comes from two sources: from radioactive
decay in the crust of the earth, and
from heat trickling through the mantle from the
earth's core.
%
% especially uranium thorium and potassium
%
In a typical continent,
the \ind{heat flow}
from the centre coming through the mantle is\marginfignocaption{\small{%
one milliwatt (1\,mW) is 0.001\,W.
}}
about $10\,\mWmm$.
The heat flow at the surface is $50\,\mWmm$.\nlabel{pMITG}
% (credit Thu 13/10/05 speaker from Bullard) James Jackson
So the radioactive decay has added an extra $40\,\mWmm$
to the heat flow from the centre.
% that dominates.
%%%%%%%%%%%%%%%% make earth
\marginfig{
%\begin{figure} \figuremargin{
\begin{center}
\mbox{\epsfbox{metapost/earth.21}}
\end{center}
%}{
\caption[a]{Temperature profile in a typical \ind{continent}.}
\label{fig.temp.prof}
}%
%\end{figure}
So at a typical location, the maximum power we can get per unit
area is $50\,\mWmm$.
But that power is not high-grade power,
it's \ind{low-grade heat} that's trickling through
at the ambient temperature up here. We presumably want to make electricity,
and that's why we must drill down.
Heat is useful only if it comes from a source
at a higher temperature than the ambient temperature.
The temperature increases with depth
as shown in \figref{fig.temp.prof}, reaching a temperature of
% in the same way as the steak in a microwave -- a parabola, roughly.
about 500\degreesC\ at a depth of
40\,km.
% as a typical ballpark figure, at which point the heat flux is one fifth.
Between depths of 0\,km where the heat flow is biggest but the
rock temperature is too low, and 40\,km, where the rocks are hottest
but the heat flow is 5 times smaller (because we're missing out on
all the heat generated from radioactive decay)
there is an optimal depth at which we should suck.
The exact optimal depth depends on what sort of sucking
and power-station machinery we use. We can bound the maximum
sustainable power
% deliverable by geothermal energy
by finding the optimal depth assuming that we have an ideal engine
for turning heat into electricity,
and that drilling to any depth is free.
%% see gnu.g
For the temperature profile shown in \figref{fig.temp.prof},
I calculated that the optimal depth is about 15\,\km.
% Here, the temperature is about 270\degreesC,
% and the heat flux is about 70\% of the flux at the surface.
Under these conditions, an
ideal heat engine would deliver 17\,\mWmm.
% TBC - need to add a note
% , or 17$\,\kW/\km^2$.
At the world population density of
43 people per square km, that's
% 0.4\,\kW\ per person, which is
10\,\kWh\ per person per day, if {\em{all}\/} land area were used.
In the UK, the population density is 5 times greater, so
wide-scale geothermal power of this sustainable-forever variety
could offer at most
\OliveGreen{2\,\kWh\ per person per day}.\label{pGeoAns}
This is the
sustainable-forever figure, ignoring hot spots, assuming
perfect power stations, assuming every square metre of continent
is exploited,
and assuming that drilling is free.
And that it is possible to drill
15-km-deep holes.
% 15-kilometre-deep holes.
\section{Geothermal power as mining}
\marginfig{
\begin{center}
\mbox{\epsfbox{metapost/earth.710}}
\end{center}
%}{
\caption[a]{Enhanced geothermal extraction from \ind{hot dry rock}.
One well is drilled and pressurized to create fractures.
A second well is drilled
into the far side of the fracture zone. Then cold water is pumped down
one well and heated water (indeed, steam) is sucked up the other.
}\label{fig.HDR}
%\end{figure}
}%
The other geothermal\index{MIT} strategy
is to
treat the heat as a resource to be mined.
In ``\ind{enhanced geothermal extraction}''\index{geothermal!enhanced}
from hot dry rocks (\figref{fig.HDR}), we
first drill down to a depth of 5 or 10\,km, and fracture
the rocks by pumping in water. (This step may create earthquakes,
which don't go down well with the locals.)
Then we drill a second well into the fracture zone. Then we pump
water down one well and extract superheated water or steam from the other.
This steam can be used to make electricity or to deliver heat.
% to things that can use heat.
What's the hot dry rock resource of the UK? Sadly, Britain is not well
endowed. Most of the hot rocks are concentrated in Cornwall,
where some geothermal experiments were carried out in 1985 in a
research facility at \ind{Rosemanowes}, now closed.
%\citet{MacDonaldStedman} report that
%RTZ Consultants Limited (RTZC) said:
%systems deeper than 6\,km were not practical.
%% drilling
%``The main conclusion of the RTZC study
Consultants assessing these experiments
concluded that
``generation of electrical power from hot dry rock was
unlikely to be technically or commercially viable in
Cornwall, or elsewhere in the UK, in the short or
medium term.''\nlabel{pMacDonaldStedman}
%\citet{MacDonaldStedman}
Nonetheless, what is the resource?
The biggest estimate of the hot dry rock resource in the
UK is a total energy of 130\,000\,TWh,
% (total energy).
% It's estimated that of this,
% 1880\,TWh might be accessible,
% most of it in \ind{Cornwall},
% and could be extracted at a rate of 75\,TWh/y, which
% is 3.4\,kWh/d per person for 25 years -- not a very sustainable
% duration! And we haven't taken into account the energy lost
% in conversion to electricity and in pumping and drilling.
% If the whole 130\,000\,TWh were magically extracted
% over 1000 years without loss,
% that would amount to 6\,kWh/d per person.
% If it were converted to electricity with an efficiency of 30\%,
% the delivered power would be 2\,kWh/d per person.
which, according to the consultants,
could conceivably contribute {\OliveGreen{1.1\,kWh per day per person}}
of electricity for about 800 years.\nlabel{pGeo1.1}
Other places in the world have more promising
hot dry rocks,\nlabel{pOtherGe} so if you want to know the geothermal
answers for other countries, be sure to ask a local.
But sadly for Britain, geothermal will only ever play a tiny part.
\qa{Doesn't Southampton use geothermal energy already? How much does
that deliver?}%
{Yes,%
\marginfignocaption{
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/southampton.eps}}
}
\ind{Southampton Geothermal District Heating Scheme}
% \ind{Southampton}, Hampshire
was, in 2004 at least,
the only geothermal heating scheme in the UK\@.
It provides the city with a supply of hot water.
The geothermal well is part of a combined heat, power, and cooling
system that delivers hot and chilled water to customers, and sells
electricity to the grid. Geothermal energy contributes about 15\%
of the 70\,GWh of heat per year delivered by this system.\nlabel{Soton}
% Their CHP system produces 70\,GWh of energy per year.
% next link is now dead....
%http://www.southampton.gov.uk/environment/energy/southampton-case-study.asp#0
% Geothermal still provides about 15\% of this.
%
% 11\,km of pipes take hot and chilled water to customers.
% Annual energy sales are 70\,GWh/y, and 23\,GWh of electricity
% from the CHP plant is sold to powergen.
The population of Southampton at the last census was 217\,445,
so the geothermal power being delivered
there is {\bf{0.13\,kWh/d}} per person in Southampton.
% 10.5 GWh/y /
}
% \newpageone
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pMITG}]
{\nqs{The heat flow at the surface is 50\,mW$\!$/m$^2$}}.
\citet{MITGeothermal} says 59\,mW$\!/\m^2$ average,
% worldwide
with a range, in the \ind{USA},
from 25\,mW to 150\,mW.
%% page 23
\citet{Shepherd03} gives 63\,m\Wmm.
\item[\npageref{pMacDonaldStedman}]
{\nqs{``Generation of electrical power from hot dry rock was
unlikely to be technically or commercially viable in the UK''}}.
Source: \citet{MacDonaldStedman}.
See also \citet{RichardsCornwall}.
%\newpage
\marginfig{
% \begin{figure}
\noindent
% {\sc Consumption}& {\sc Production}\\
{\mbox{\epsfbox{metapost/stacks.287}}}\\%33}} }\\
% }{
\caption[a]{Geothermal.
}\label{fig.geotherm}
}
% \end{figure}
\item[\npageref{pGeo1.1}]
{\nqs{The biggest estimate of the hot dry rock resource in the
UK \ldots\
could conceivably contribute {{1.1\,kWh per day per person}}
of electricity for about 800 years}}.
Source: \citet{MacDonaldStedman}.
\item[\npageref{pOtherGe}]
{\nqs{Other places in the world have more promising
hot dry rocks}}.
% \pageref{pMITg}]
There's a good \index{MIT}study \citep{MITGeothermal}
describing the USA's \ind{hot dry rock}\index{geothermal!hot dry rock}
resource.
% \myurl{http://web.mit.edu/newsoffice/2007/geothermal.html}.
%\item[]
% There is a super animation at
% \tinyurl{2cv3ry}{http://www1.eere.energy.gov/geothermal/egs_animation.html}.
Another more speculative
approach, researched by \ind{Sandia National Laboratories} in the 1970s,
is to drill all the way down to \ind{magma}\index{geothermal!magma}
at temperatures
of 600--1300\degreesC, perhaps 15\,km deep, and get power there.
The website \myurl{www.magma-power.com} reckons that the heat in
pools of magma under the US would cover US energy consumption for
500 or 5000 years, and that it could be extracted economically.
\item[\npageref{Soton}]
{\nqs{\ind{Southampton Geothermal District Heating Scheme}}}.
\myurlb{www.southampton.gov.uk}{http://www.southampton.gov.uk/}.
\end{notelist}
\normalsize
% StatoilHydro ASA joins the Iceland Deep Drilling Project (20.06.2008)
% http://www.os.is/Apps/WebObjects/Orkustofnun.woa/1/wa/dp?id=9267&wosid=jJxbyMXWdjOYCpIYdvhSBw
% aim:
% produce energy and chemicals from geothermal systems at supercritical conditions. This will require drilling to depths of 4 to 5 km in order to reach temperatures of 400%G–%@600°C .
% see
% http://www.iddp.is/
% they talk of a few 10MW
%\subchaptercontents{Can we live on renewables?}
\rset\chapter{\rcol{Public services}}
\label{ch.military}
%\section{`Defense'}
% The point of this chapter is to note things that
% we spend energy on that we could perhaps stop spending
% energy on.
\marginpar{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/MilTrenchS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/MilTrench.jpg.eps}}}
\\
\end{tabular}
\end{center}
\label{ptrench}
% \caption[a]{ }
}\myquote{Every gun
that is made, every warship launched, every rocket fired signifies, in the final sense, a theft from those who hunger and are not fed, those who are cold and are not clothed.
This world in arms is not spending money alone.
It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children.
% The cost of one modern heavy bomber is this: a modern brick school in more than 30 cities.
% It is two electric power plants, each serving a town of 60\,000 population.
%%\ldots
%%
%It is two fine, fully equipped hospitals.
%It is some fifty miles of concrete pavement.
% We pay for a single fighter plane with a half million bushels of wheat.
% We pay for a single destroyer with new homes that could have housed more than 8,000 people.
%% This is, I repeat, the best way of life to be found on the road the world has been taking.
%% This is not a way of life at all, in any true sense. Under the cloud of threatening war, it is humanity hanging from a cross of iron. These plain and cruel truths define the peril and point the hope that come with this spring of 1953.
%% http://www.edchange.org/multicultural/speeches/ike_chance_for_peace.html
% (American 34th President (1953-61). 1890-1969)
}{President
Dwight D.\
% Dwight David
Eisenhower -- April,
1953\index{Eisenhower, D.D.}\index{President Dwight D.\ Eisenhower}
% \cite{Eisenhower}
}
% \end{quote}
% in US edition, use defense
\section{The energy cost of ``defence''}
Let's
% look at some numbers for the \UK, to
try to estimate
how much energy we spend on our military.
\marginpar{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/paladin.eps}}}%
\\
\end{tabular}
\end{center}
\label{ppaladin}
% \caption[a]{ }
}
In 2007--8,
the fraction of British
central government expenditure that went to defence was
\pounds33\,billion/\pounds587\,billion = 6\%.\nlabel{pwars0}
% 0.057
% In 2004,
% the fraction of central government expenditure that went to `defence' was
% \pounds24\,billion/\pounds360\,billion = 6.8\%.
%% 24.543 billion / 360.580 = 0.068065 \\
% The cost of replacing the Trident nuclear weapon system
% is estimated to be
% ..........
% http://www.mod.uk/DefenceInternet/AboutDefence/Organisation/KeyFactsAboutDefence/DefenceSpending.htm
% Budget in 2007-8 is 33.447 bill
% annual report and accounts
% http://www.mod.uk/DefenceInternet/AboutDefence/CorporatePublications/AnnualReports/MODAnnualReports0607/ModAnnualReportAndAccounts200607.htm
% Overall budget for securtity and intelligence in 2007-2008 is £2.25bn
% http://www.guardian.co.uk/uk_news/story/0,,2039284,00.html
% Now, in 2008, the annual defence budget is up to \pounds33\,billion.
If we include the UK's spending on counter-terrorism and intelligence
(\pounds 2.5\,billion per year and rising), the total for
defensive activities comes to \pounds36\,billion.
% _military.tex
As a crude estimate we might guess that 6\% of this
\pounds36\,billion is spent on energy at a cost of 2.7p per \kWh.
(6\% is the fraction of GDP that is spent on energy, and
2.7p is the average price of energy.)
% , as we saw on \pref{pageGDP}.)
That works out to about 80\,TWh per year of energy
going into defence: making bullets, bombs, \index{nuclear!weapon}nuclear weapons;
making devices for delivering bullets, \ind{bomb}s, and nuclear weapons;
and roaring around
% in boats,
% jeeps,
% tanks, and planes,
% terrorising the populace while
keeping in trim for the next game of \ind{good-against-evil}.\index{war}
In our favourite units, this corresponds to
% 3.6505
% {\bf{3.7\,kWh per day per person}}, or 3\% of UK energy.
{\Red{4\,kWh per day per person}}.
% Using the same method, the energy expenditure by the USA on `defense'
% is {\bf{5\,kWh per day per person}}.
% pr 480e9 * 0.06 / 0.05 / 365.25 / 300e6
% 5.25667351129363
% Call me \naive, but I think that both we and our alleged enemies would
% all benefit if we disbanded most of our military. I am privileged
% to have friends from Sudan; these friends were in Khartoum in 1998 when the
% the USA bombed the al-Shifa pharmaceutical factory, and they told me
% that ordinary Sudanese people still feel threatened by
% America (imagine that!), and feel an urge to enhance their defences.
% I wish that Sudanese people didn't feel this need to waste resources
% on arming themselves.
\section{The cost of nuclear defence}
The financial expenditure by the USA
on manufacturing and deploying nuclear weapons from 1945 to 1996 was
\$5.5\,trillion (in 1996 dollars).\nlabel{pSchwar}
%Compare NON-NUCLEAR spending
% 1940-1996, as documented by the Office of Management and Budget.
% The bar at a the extreme left is for national defense and totals \$13.2 trillion.
% (Add back 5.5 to include nuclear)
Nuclear-weapons spending over this
% 56-year
period exceeded the combined total federal spending for education;
agriculture; training, employment, and social services; natural resources
and the environment; general science, space, and technology; community and
regional development (including disaster relief); law enforcement; and
energy production and regulation.
% On average, the United States has spent \$98 billion a year on nuclear weapons.
%Where did all this money go?
%``From 1948 through 1996, the United States spent \$165.5 billion manufacturing
% plutonium, highly-enriched uranium, tritium, and other materials necessary to make nuclear explosives.
% That spike in 1953 is not a mistake.
If again we assume that 6\% of this expenditure
went to energy at a cost of
5\cents\ per \kWh, we find that the energy cost
of having nuclear weapons was 26\,000\,kWh per American, or
% 26400 pr 5.5e12 * 0.06 / 0.05 / 250e6
{\Red{1.4\,kWh per day per American}} (shared among 250\,million Americans
over 51 years).
% pr 5.5e12 * 0.06 / 0.05 / 365.250 / 51.0 / 250e6
% pr 5.5e12 * 0.06 / 0.05 / 250e6
% [I use 250\,million rather than the current
% 300\,million to represent the
% typical USA population during 1945--1996.]
% \marginpar{
% \begin{center}
% \begin{tabular}{@{}c@{}}
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/mlrs1.jpg.eps}}}
%\\
% \end{tabular}
% \end{center}
%% \caption[a]{ }
%}
% If we assumed that {\em{all}\/} the money went on energy we'd get
% 24\,kWh/d per person.
What energy would have been delivered to the lucky recipients, had all
those nuclear weapons been used?
The energies of the biggest thermonuclear
weapons developed by the USA and USSR
are measured in megatons of TNT\@.
% (Several tests of 10, 15, 30)
A ton of TNT
% , (a metric ton = 1000 kg) is therefore 4.184 × 109 J =
is
% 4.2 gigajoules
% (GJ) or
1200\,kWh.
% is 4.184 gigajoules (GJ) or 1162\,kWh.
%# A kiloton of TNT is therefore 4.184 × 1012 J = 4.184 terajoules (TJ).
%# A megaton of TNT is 4.184 × 1015 joules = 4.184 petajoules
The bomb that destroyed Hiroshima
% nearly 53 years ago
had the energy
of 15\,000 tons of \ind{TNT}\index{kiloton}
% or 15 {\ind{kiloton}s}
(18 million kWh).
% -- that's
%45\,kWh per resident of Hiroshima.
\marginfig{
% \begin{figure}
% \begin{center}
% \begin{tabular}{@{}cc}
% {\small\sc Consumption}& {\small\sc Production}\\
% \multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.611}}} \\
{\mbox{\epsfbox{metapost/stacks.288}}}
%\end{tabular}
% \end{center}
% }{
\caption[a]{The energy cost of defence in the UK is
estimated to be about 4\,kWh per day per person.
}\label{fig.defen}
}%
A {\em\ind{megaton}\/} \ind{bomb} delivers an energy of
1.2 billion kWh.
If dropped on a city of one million, a megaton bomb makes
an energy donation of 1200\,kWh per person, equivalent to 120\,litres
of petrol per person.
% To try to bring this figure into
% perspective, a gigawatt-year (the energy output of a
% big power station over one year)
% is 9\,billion\,kWh.
The total energy of the USA's nuclear arsenal today is
% 2.4 million kilotons.
2400 megatons,
contained in 10\,000 warheads.
% see data/bombs for working
In the good old days when folks really took defence seriously,
the arsenal's energy was 20\,000 megatons.
% http://www.brook.edu/fp/projects/nucwcost/figure3.htm
These bombs, if used, would have delivered an energy of about 100\,000\,kWh
per American.
% So in summary, I estimate that making the USA's nuclear weapons had an energy
% cost of at least 1.4\,kWh/d per American, non-stop over 51 years.
%% and if they could be used in a reactor ... 10 kWh/d/p for 30 years
%\subsection{Putting it all together}
% In the past, the USA had three times as many warheads, so perhaps
% an energy of seven thousand megatons.
%
% So the energy per US citizen stored in those bombs was
% 28\,000 kWh each.
% (Or, shared out among 6 billion humans on the planet,
% it's an energy donation of 1400\,kWh per recipient.)
% If that total energy of those bombs were spread
% It is 66GW times 40y.
That's equivalent to 7\,kWh per day per person for a duration of
40 years -- similar to all the electrical energy
supplied to America by nuclear power.
% they have 100GW now
%\subsection{Other facts}
% Peak number of warheads in 1965: 32\,000; and in 1975, 28\,000.
% Hiroshima was 15\,kt, Nagasaki was 22\,kt.
\subsection{Energy cost of making nuclear materials for bombs}
The main nuclear materials are plutonium, of which the USA has produced
104\,t, and high-enriched uranium (HEU), of which the
USA has produced 994\,t. Manufacturing these materials requires energy.
%Plutonium production:
The most efficient \ind{plutonium}-production facilities
use 24\,000\,kWh of heat when producing
1 gram of plutonium.\nlabel{pPlut}
% 1g per megawatt-day (thermal)
% 1 megawatt day = 24 000 kilowatt hours
% Israel: Plutonium created through 1994: Up to 870 kilograms
% ISIS estimates that at the end of 2003 there was a total of 1,855 tonnes of plutonium and 1,900 tonnes of HEU globally.
%
So the direct energy-cost of making the USA's 104 tons of plutonium
% http://en.wikipedia.org/wiki/Nuclear_weapons_and_the_United_States#Current_status
(1945--1996) was at least
%% $104\,000\,000 \times 24\,000\,\kWh =
% $2.5 \times 10^{12}\,\kWh$
2.5 trillion kWh
which is
0.5\,kWh per day per person (if shared between 250 million Americans).
%% this
%% http://www.world-nuclear.org/info/inf28.htm
%% contains a list of centrifuge capacities worldwide. Lots of details.
% The electromagnetic isotope separation (EMIS) process was developed in the early 1940s in the Manhattan Project to make the highly enriched uranium used in the Hiroshima bomb, but was abandoned soon afterwards. However, it reappeared as the main thrust of Iraq's clandestine uranium enrichment program for weapons discovered in 1992. EMIS uses the same principles as a mass spectrometer (albeit on a much larger scale). Ions of uranium-238 and uranium-235 are separated because they describe arcs of different radii when they move through a magnetic field. The process is very energy-intensive - about ten times that of diffusion.
The main energy-cost in manufacturing HEU is the cost of enrichment.
Work is required to separate the {\Ur{235}} and {\Ur{238}} atoms
in natural \ind{uranium} in order to create a final product that
is richer in {\Ur{235}}.
The USA's production of 994 tons of highly-enriched
uranium (the USA's total, 1945--1996)
% cost 230\,million\,SWU, which was
had an energy cost of about
0.1\,kWh per day per person.\nlabel{pCentrif}
%(assuming 250 million Americans, and
%using 2500\,kWh/SWU as the cost of diffusion enrichment.)
% [Using 2400 as the cost of diffusion enrichment.]
% pr 232 * 994000
% SWU at 100dollar means value of all that uranium is 23 Billion dollars.
% pr 232.0 * 994000 *2400 / ( 250e6 * 51 * 365.25 )
% 0.12
% pr 232.0 * 994000 *2500 / ( 250e6 * 51 * 365.25 )
% 0.1238
% The first large-scale uranium enrichment facility, the Y-12 plant at Oak Ridge, Tennessee, used EMIS in devices called "calutrons."
% \pagebreak[4]
% \section{Arguments}
\myquote{\mbox{``Trident creates jobs.''}
Well, so does relining our schools with asbestos, but that doesn't
mean we should do it!}{Marcus Brigstocke}
% Sat 3/3/07
% \section{Education} UNIV
\section{Universities}
According to Times Higher Education Supplement (30 March 2007),
% p14.
\UK\ universities use 5.2 billion kWh per year.
Shared out among the whole population, that's a power of
\Red{0.24\,kWh per day per person}.
% cut material to _benchmarks.tex
So higher education and research
seem to have a much lower energy cost than
defensive war-gaming.
There may be other energy-consuming public services we could talk about,
but at this point I'd like to wrap up our race between
the red and green stacks.
% To use a violent metaphor,
% could we perhaps kill two birds with one stone by promoting peace
% instead of war? First,
% the economic savings could be put into sustainable energy
% projects and everything else the Stern review recommended,
% and into peace-building initiatives.
% Second, military activities and resources are notoriously
% big consumers of energy, so by cutting our militaries, we could
% surely save a significant amount of energy.
\newpage
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
% \item[\pageref{pmili}:] {\sc military}
% I am aware that `military' is strictly an adjective referring to
% soldiers (rather than other forms of offense such as naval forces).
% But I am not willing to use the doublespeak `defense' to refer to
% war-machine.
\item[\npageref{pwars0}] {\nqs{military energy budget}}.
% www.conscienceonline.org.uk
%
% www.hm-treasury.gov.uk/media/8AC/F7/Executive_Summary.pdf
The
UK budget can be found at
\tinyurl{yttg7p}{http://budget2007.treasury.gov.uk/page_09.htm};
defence gets \pounds33.4\,billion
\tinyurl{fcqfw}{http://www.mod.uk/DefenceInternet/AboutDefence/Organisation/KeyFactsAboutDefence/DefenceSpending.htm}
% http://www.hm-treasury.gov.uk/media/D/A/pbr_csr07_pn04sia10.pdf
% better same ref is
% http://press.homeoffice.gov.uk/press-releases/security-prebudget-report
and intelligence and counter-terrorism \pounds 2.5\,billion per year
\tinyurl{2e4fcs}{http://press.homeoffice.gov.uk/press-releases/security-prebudget-report}.
% I don't understand how government budgets work, but
% the {\em{expenditure}\/} of the Department of Defence
According to p14 of the
Government's Expenditure Plans 2007/08
\tinyurl{33x5kc}{http://www.mod.uk/NR/rdonlyres/95BBA015-22B9-43EF-B2DC-DFF14482A590/0/gep_200708.pdf},
the ``total resource budget'' of the Department of
Defence is a bigger sum,
\pounds39\,billion, of which \pounds33.5\,billion goes for
``provision of defence capability'' and \pounds6\,billion
for armed forces pay and pensions and war pensions.
A breakdown of this budget can be found here: \tinyurl{35ab2c}{http://www.dasa.mod.uk/natstats/ukds/2007/c1/table103.html}.
% I assumed in this chapter
% that the energy intensity of these defence activities was 6\%,
% the same as the energy intensity of the UK economy --
% an assumption made on account of the difficulty of finding the
% true energy intensity of the people in uniform;
% however, as I muse on the energy used
% in tanks, warships, jet fighters, and rockets
% I can't help but guess that the true energy intensity must
% be above the UK average.
% MOD water: 24 M cubic m.
% research finromtiaont:
% http://www.mod.uk/DefenceInternet/DefenceFor/Researchers/OfficialDefenceInformationAndStatistics.htm
% led me to
% http://www.mod.uk/NR/rdonlyres/A5810AB5-6CDB-4B97-A8CF-976D3B9676B4/0/defence_plan2007.pdf
% points to Ministry of Defence Efficiency Technical Note 2005 available at www.mod.uk
% MOD owns 240,000 ha which is 1% of UK land mass.
% there was no useful info in that 2007 pdf^^^
% expenditure plans 2007-8: July 2007.
% http://www.mod.uk/NR/rdonlyres/95BBA015-22B9-43EF-B2DC-DFF14482A590/0/gep_200708.pdf
% has more links on page 5.
% \tinyurl{yk74d3}{http://www.hm-treasury.gov.uk/media/8AC/F7/Executive_Summary.pdf}
% siteresources.worldbank.org/DATASTATISTICS/Resources/GDP.pdf
See also
\tinyurl{yg5fsj}{http://siteresources.worldbank.org/DATASTATISTICS/Resources/GDP.pdf},
% www.sipri.org/contents/milap/milex/mex_major_spenders.pdf/download
\tinyurl{yfgjna}{http://www.sipri.org/contents/milap/milex/mex_major_spenders.pdf/download},
and
\myurlb{www.conscienceonline.org.uk}{http://www.conscienceonline.org.uk/}.
The \ind{US military}'s energy consumption is published:
\marginpar[b]{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/mlrs3.jpg.eps}}}
\\
\end{tabular}
\end{center}
\label{pmlrs}
% \caption[a]{ }
}%
``The \ind{Department of Defense}
is the largest single consumer of energy in the United
States. In 2006, it spent \$13.6 billion to buy 110 million barrels of petroleum fuel
[roughly 190 billion kWh]
and 3.8 billion kWh of electricity'' \citep{DODMoreFight}.
This figure describes the direct use of fuel and electricity and doesn't include
the embodied energy in the military's toys.
Dividing by the US population of 300 million, it comes to
{\Red{1.7\,kWh/d per person}}.
\item[\npageref{pSchwar}]
{\nqs{The financial expenditure by the USA
on manufacturing and deploying nuclear weapons from 1945 to 1996 was
\$5.5\,trillion (in 1996 dollars)}}.
Source: \citet{Schwartz98}.
% \myurl{http://www.brook.edu/fp/projects/nucwcost/schwartz.htm}.
\item[\npageref{pPlut}]
{\nqs{Energy cost of \ind{plutonium} production}}.
\tinyurl{slbae}{http://www.wisconsinproject.org/countries/israel/plut.html}.
\item[\npageref{pCentrif}] {\nqs{The USA's production of 994 tons
of HEU\ldots}}
Material enriched to between 4\% and 5\%
{\Ur{235}} is called \ind{low-enriched uranium} (\ind{LEU}).
90\%-enriched uranium is called \ind{high-enriched uranium} (\ind{HEU}).
It takes three times as much
% separative
work to enrich uranium from its natural state to 5\% LEU
as it does to enrich LEU to 90\% HEU\@.
The nuclear power industry measures these energy requirements in
a unit called the
\ind{separative work unit} (\ind{SWU}).\label{pSWU}
%The number of SWU that would normally be used t
To produce a kilogram of {\Ur{235}} as HEU
% (about 1.05\,kg of HEU)
takes 232\,SWU\@. To make 1\,kg of {\Ur{235}}
as LEU (in 22.7\,kg of LEU) takes about 151\,SWU\@. In
both cases one starts from natural uranium
(0.71\% {\Ur{235}}) and discards depleted uranium containing 0.25\% {\Ur{235}}.
\amarginfignocaption{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/NTS_Barrage_BalloonS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/NTS_Barrage_Balloon.jpg.eps}}}
\\
\end{tabular}
\end{center}
\label{pbarrageb}
% \caption[a]{ }
}%
The commercial nuclear fuel market values an SWU at about \$100.
It takes about 100\,000\,SWU of enriched uranium
to fuel a typical 1000\,MW commercial nuclear reactor for a year.
Two uranium enrichment methods are currently in commercial use: gaseous diffusion and gas centrifuge.
The gaseous diffusion process consumes about 2500\,kWh
% source is http://www.globalsecurity.org/wmd/intro/u-centrifuge.htm
% (9000\,MJ) 2ywzee
per SWU, while modern gas centrifuge plants require
only about 50\,kWh
% (180\,MJ)
per SWU\@.
\tinyurl{yh45h8}{http://www.usec.com/v2001_02/HTML/Aboutusec_swu.asp},
\tinyurl{t2948}{http://www.world-nuclear.org/info/inf28.htm},
\tinyurl{2ywzee}{http://www.globalsecurity.org/wmd/intro/u-centrifuge.htm}.
A modern centrifuge
produces about 3\,SWU per year.
% \nlabel{pCentrif}
% 35-62 kWh per SWU according to \cite{DonesOnStorm}
%
%% 40-50 kWh per SWU. according to
%% http://www.globalsecurity.org/wmd/intro/u-centrifuge.htm
%
%% http://www.foreignaffairs.org/20050301faresponse84214/mitchell-b-reiss-robert-gallucci/red-handed.html
%% this article about Korean U is full of useful numerical facts.
% used in Pakistan or in the European enrichment enterprise
% may be assumed to
% 50\,000 centrifuges could provide 150\,000/232 = 647\,kg of {\Ur{235}} as HEU.
The USA's production of 994 tons of highly-enriched
uranium (the USA's total, 1945--1996)
cost 230\,million\,SWU, which works out to
0.1\,kWh/d per person (assuming 250 million Americans, and
using 2500\,kWh/SWU as the cost of diffusion enrichment).
% {\nqs{Energy requirements of an \ind{SWU}.}}
\end{notelist}
\normalsize
\bset\chapter{\bcol{Can we live on renewables?}}
\label{ch.halftime}
% THIS CHAPTER IS GOING TO BE REWRITTEN.
%
% It's now the transition chapter between traditional
% renewables and other possibly-sustainable
% technologies such as nuclear.
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}cc}
% {\small\sc Consumption}& {\small\sc Production}\\
\multicolumn{2}{@{}c}{\mbox{\epsfbox{metapost/stacks.388}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{The state of play after we added up all the
traditional renewables.
}
\label{fig.halftime}
}%
% \end{figure}
The red stack in \figref{fig.halftime} adds up to \Red{195\,kWh per day per
person}. The green stack adds up to about \OliveGreen{180\,kWh/d/p}.
A close race!
% Oh dear!
% We're half-way through Part I, and
% 2+14+4+32+16+1.5+24+5+12+20
% 130
% Things are looking pretty bad for the sustainable production
% stack.
% The sustainable production stack
% is not far behind the stack of affluent consumption.
%% The sustainable production stack
%% has a slight lead, but please don't
%% think this lead was easy to come by!
% We've included in the
% production stack all the traditional renewables,
% and, even throwing economic constraints to the wind,
% the production stack can't match the stack of affluent
% consumption, which has topped 160\,kWh per day.
% and that stack hasn't reached 100\,kWh per day.
% Meanwhile we're running out of space for our stack of
% affluent consumption, which has topped 160\,kWh per day.
% And we haven't yet included all forms of consumption.
% Remember, in calculating our production stack
But please remember: in calculating our production stack
we threw all economic, social, and environmental constraints to the wind.
Also, some of our green contributors are probably
incompatible with each other: our photovoltaic panels
and hot-water panels would clash with each other on roofs;
and our solar photovoltaic farms using 5\%
of the country might compete with the energy crops
with which we covered 75\% of the country.
If we were to lose just one of our bigger green contributors --
for example, if we decided that deep offshore wind is not an option,
or that panelling 5\% of the country with photovoltaics
at a cost of \pounds200\,000 per person
is not on -- then the production stack would no longer match the
consumption stack.
%\section{Are we comparing like with like? Are the renewables interchangeable?}
% I've plopped all the conceivable green contributions in a single stack
% and compared their total with the red consumption stack.
Furthermore, even if our red consumption
stack were lower than our green production stack, it
would not necessarily mean our energy sums are adding up.
You can't power a \index{television}TV with \ind{cat} food, nor can you
% You can't
feed a cat from a wind turbine.
Energy exists in different forms -- chemical,
electrical, kinetic, and heat, for example.
For a sustainable energy plan to add up, we need
both the {forms} and amounts of energy consumption and production
to match up.
Converting energy from one form to another
-- from chemical to electrical,\index{energy conversion}
as at a fossil-fuel \ind{power station}, or from electrical to chemical, as in a
% water-hydrolysis
factory making hydrogen from water --
usually involves substantial losses of useful energy.
We will come back to this important detail
in \chref{ch.plan}, which will describe some energy plans
that do add up.
Here we'll reflect on our estimates of consumption and
production, compare them with official averages and with other
people's estimates, and discuss how much power renewables could plausibly
deliver in a country like Britain.
The questions we'll address in this chapter are:
\begin{enumerate}
\item
Is the size of the red stack roughly correct?
What is the {\em{average}\/} consumption of Britain?
We'll look at the official energy-consumption numbers for
Britain and a few other countries.
\item
Have I been unfair to
renewables, underestimating their potential?
We'll compare the estimates in the green stack
with estimates published by organizations such as the
Sustainable Development Commission,
the Institution of Electrical Engineers, and
the Centre for Alternative Technology.
\item
What happens to the green stack
when we take into account social and
economic constraints?
\end{enumerate}
\section{Red reflections}
Our estimate of a typical affluent person's
consumption (\figref{fig.halftime}) has reached {\Red{{195\,kWh per day}}}.
It is indeed true that many people use this much energy,
and that many more aspire to such levels of consumption.
The {\em{average}\/} \ind{American} consumes about {\Red{\bf{250\,kWh per day}}}.
If we all raised our standard of consumption to an average American level,
the green production stack would definitely be
dwarfed by the red consumption stack.
What about the average European and the average Brit?
Average\index{Europe}\index{consumption!European}
European consumption of ``primary energy'' (which means the energy contained in raw fuels,
plus wind and hydroelectricity) is about {\Red{\europe\,kWh per day
per person}}.
% (See this chapter's notes
% for discussion of this figure.)
% [This would be a good point to
% summarize the actual breakdown of UK energy consumption?]
The UK average is also {\Red{\europe\,kWh per day per person}}.\nlabel{pUKAV}
% simply display in each diagram an indicator of a
These official averages do not include two energy flows.
First, the ``embedded energy'' in {\em{imported}\/} stuff
(the energy expended in making the stuff)
is not included at all.
We estimated in \chref{ch.stuff}
that the embedded energy in imported stuff
is at least 40\,kWh/d per person.
Second, the official estimates of ``primary energy consumption''
include only industrial energy flows -- things like
fossil fuels and hydroelectricity -- and don't keep track of the
natural embedded energy in food: energy that was originally
harnessed by photosynthesis.
% ; nor do they keep track of other uses of solar such as drying washing,...
% Our estimate of the energy required
% to keep the food chain going was something like 16\,kWh/d per person.
% Official energy-consumption figures work a bit differently
% from the figures we've calculated so far. First, while they
% include the energy in imported fuel, the official numbers
% I'm about to quote don't include any embodied energy in
% imported goods. Our estimate was that imported stuff
% had an embodied energy of at least 40\,kWh per day per person.
% Second, official calculations focus on the inputs and
% outputs of power stations and chemical plants -- fossil fuels,
% nuclear fuels, and hydroelectricity, mainly; and, apart from
% biofuels that end up passing through power stations and chemical
% plants, they don't take account of the energy acquired from the sun
% by farming. So the official figures omit much of the `Food'
% chunk in our consumption stack, which was another 16\,kWh per day per
% person.
Another difference between the red stack we slapped together
% this book's energy consumption estimates so far
and the national total is that in most of the consumption
chapters so far
we tended to ignore the energy lost in converting energy from one
form to another, and in transporting energy around.
For example, the ``car'' estimate in Part I
covered only the energy in the petrol,
not the energy used at the oil refinery that makes the petrol,
nor the energy used in trundling the oil and petrol from A to B\@.
The national total accounts for all the energy, before any conversion
losses. Conversion losses in fact account for about 22\% of total
national energy consumption. Most of these conversion losses\index{conversion losses}
happen at power stations. Losses in the electricity transmission\index{transmission losses} network
chuck away 1\% of total national energy consumption.\nlabel{pLosses}\index{electricity grid!losses}\index{grid!losses}\index{loss!transmission losses}\index{national grid!transmission losses}\index{electricity!losses}\index{power line losses}
% I got this by hitting 0.08 * 17.5/129.57
% 55 of 244
% % railways are 2900 GWh elec
% And 53.5\,Mtoe of energy value
% is lost in the process of converting
% energy from one form to another (for
% example producing electricity, which chucks heat up cooling towers).
% So final users actually use 65\%
% of the ``primary demand''.
When building our red stack, we
tried to imagine how much energy a typical affluent person
uses. Has this approach biased our perception of the
importance of different activities?
Let's look at some official numbers.
\Figref{fig.OfficialBreakdown} shows the breakdown of energy consumption
by end use.
\marginfig{
\begin{center}
\begin{tabular}{@{}c}
%{\sc Consumption by end use}\\
\multicolumn{1}{@{}c}{\mbox{\epsfbox{metapost/stacks.122}}} \\
\end{tabular}
\end{center}
\caption[a]{Energy consumption, broken down
by end use, according to the Department
for Trade and Industry.}\label{fig.OfficialBreakdown}
}%
The top two categories are transport and heating (hot air and hot water).
Those two categories also dominated the red stack in Part I\@. Good.
\begin{table}[bhp]
\figuremargin{
\begin{tabular}{llr} \toprule
Road transport & Petroleum & 22.5\\% 42.51\\
Railways &Petroleum & 0.4\\% 0.73\\ 0.39
Water transport& Petroleum & 1.0\\% 1.81\\ 0.96
Aviation & Petroleum & 7.4 \\% 14.00\\
All modes & Electricity & 0.4\\% 0.73 \\ 0.39
\midrule
\multicolumn{2}{l}{All energy used by transport} & 31.6\\% 59.78 \\
\bottomrule
\end{tabular}
%%Mtoe 42.51000 0.73000 1.81000 14.00000 0.73000
%%kWh/d/p 22.50139 0.38640 0.95807 7.41048 0.38640
}{
\caption[a]{
2006 breakdown of energy consumption by transport mode, in kWh/d per person.
\par
% , in Mtoe.\\
Source: \cite{TSGB}.
}\label{tab.transp}
}
\end{table}
%\newpageone
Let's look more closely at transport. In our red stack, we found
that the energy footprints of driving a car 50\,km per day and of
flying to Cape Town
% Los Angeles
once per year are roughly equal.
\Tabref{tab.transp} shows
the relative importances of the different transport
modes in the national balance-sheet.
In the national averages, aviation is smaller than road transport.
% So
% if you are a frequent flyer, flying probably dominates your
% personal
% energy footprint; but nationally, road transport is
How do Britain's official consumption figures compare with those
of other countries?
\begin{figure}
\figuremargin{
\begin{center}
{\mbox{\epsfxsize=\textwidth\epsfbox{../../data/humandev/EnALL.eps}}}% GDP on linear scale
% made by gnuALL
\end{center}
}{
\caption[a]{Power consumption per capita, versus
\ind{GDP}\index{data!energy consumption}\index{world}\index{countries}\index{data!GDP}
per capita, in purchasing-power-parity US dollars.
Squares show countries having
``high human development;'' circles,
``medium'' or ``low.'' \Figref{fig.En1} (\pref{fig.En1}) shows the same data
on logarithmic scales.
% \tinyurl{3av4s9}{http://hdr.undp.org/en/statistics/}
}\label{fig.En2}
}
\end{figure}
\Figref{fig.En2} shows the power consumptions of
lots of countries or regions, versus their gross domestic products (GDPs).
% \Figref{fig.En1} shows the same data
% on logarithmic scales.
There's an evident correlation between power consumption
and GDP: the higher a country's GDP (per capita), the more power it consumes
per capita. The UK is a fairly typical high-GDP country,
surrounded by Germany, France, Japan, Austria, Ireland, Switzerland,
and Denmark. The only notable exception to the rule ``big GDP implies
big power consumption'' is Hong Kong. Hong Kong's GDP per capita
is about the same as Britain's, but Hong Kong's
power consumption is about \Red{80\,kWh/d/p}.
\begin{figure}[tbp]
\figuremargin{
\begin{center}
\epsfxsize=\textwidth%
{\epsfbox{../../images/Hong_KongML.eps}}%
\end{center}
}{
\caption[a]{Hong Kong.
{Photo by Samuel Louie and Carol Spears.}
}\label{fig.HK}
}
\end{figure}
The message I take from these country comparisons is that the UK is
a fairly typical European country, and therefore provides
a good case study for asking the question ``How can a country
with a high quality of life get its energy sustainably?''
\begin{figure}
%\figuredangle{
%\fullwidthfigure{ canged Thu 11/9/08
\fullwidthfigureright{
\begin{center}
\mbox{\epsfbox{metapost/stacks.801}}
\end{center}
}{
\caption[a]{Estimates
of theoretical or practical renewable resources in the \UK,
by the Institute of Electrical Engineers,
the Tyndall Centre, the Interdepartmental Analysts Group, and the
Performance and Innovation Unit; and the proposals from the Centre for Alternative Technology's
``Island Britain'' plan for 2027.
}
\label{fig.TynPiu}
}
\end{figure}
\section{Green reflections}
% Before we address this question, however, perhaps you would like to
% double-check the conclusion of Part I.
People often say
that Britain has plenty of renewables. {Have I been mean to green?}
Are my numbers a load of rubbish? Have I underestimated
sustainable production? Let's compare my green
numbers first with
% other organizations'
several estimates found in the \ind{Sustainable Development Commission}'s
publication {\em The role of nuclear power in a low carbon economy.
% Paper 2:
Reducing \COO\ emissions --
nuclear and the alternatives.}
% (March 2006).
Remarkably, even though the Sustainable Development Commission's
take on sustainable resources is very positive
(``We have huge tidal, wave, biomass and solar resources''),
{\em all the estimates in the
Sustainable Development Commission's
document are smaller than mine!\/}
(To be precise, all the estimates of the renewables total
are smaller than my total.)
The Sustainable Development Commission's
publication gives estimates from four sources
detailed below
(IEE, Tyndall, IAG, and PIU).
\Figref{fig.TynPiu}
% {figIEEetc}
shows my estimates alongside numbers from
these four sources and numbers from
the Centre for Alternative Technology (CAT).
% as a green stack alongside the national average
% consumption of \europe\,kWh/d per person.
Here's a description of each source.
\begin{description}
\item[IEE]
%%% http://www.theiet.org/publicaffairs/energy/renewable.cfm
%%% http://www.theiet.org/publicaffairs/energy/renewableintheuk.pdf
%%% the above seems to be a fresh 2006 version: see
%%% xpdf /home/mackay/sustainable/refs/renewableintheuk.pdf
%% 3.3.1 IEE Â renewable energy in the UK
The Institute of Electrical Engineers published
a report on renewable energy in 2002 -- a
summary of possible contributions from renewables in the UK\@.
The second column of \figref{fig.TynPiu} shows
the ``technical potential'' of a variety of
renewable technologies for UK electricity
generation -- ``an upper
limit that is unlikely ever to be exceeded
even with quite dramatic changes in the
structure of our society and economy."
\label{pagebleak}
%
% Table \ref{tab.iee} shows their summary figures.
% in TWh/year, and
% in kWh per day per person.
According to the IEE, the total of all renewables' technical potential
is about 27\,kWh/d per person.
% Same as current electricity consumption, roughly.
% And that is the IEE's upper limit.
% The table does not include any contribution from solar energy except
% biomass.
% Their figures for biomass and wave all agree with mine;
% their estimates for tide and wind are quite a lot smaller than mine;
% The only figure in their list that is bigger than mine
% is geothermal, presumably because they did not impose the
% ``sustainable'' constraint that I did.
% , where I would readily admit my estimate was not founded
% on any knowledge of \UK\ geology.
% I think their geothermal estimate,
% however, doesn't qualify as `sustainable' by the definition we've been using,
% because the IEE imagine mining the heat in hot rocks over a time shorter
% than 1000\,years.
%% Tyndall Centre (2003). Renewable energy and combined heat and power resources in the UK. Available
%% from: http://www.tyndall.ac.uk/publications/working_papers/wp22.pdf
%% authors:
%% Jim Watson, Julia Hertin, Tom Randall and Clair Gough
%% Working paper 22.
%% address={Tyndall Centre for Climate Change Research}
%% in this paper they just copy things straight from ETSU.
%% so need to go find ETSU.
%5 ETSU, 2000. New and renewable energy: Prospects in the UK for the 21st century:
%% http://www.dti.gov.uk/renew/condoc/ NO LONGER WORKS
%% http://www.dti.gov.uk/files/file21102.pdf
%% www.dti.gov.uk/renew/ropc.pdf
%% Hmm - wave: 21102.pdf just baldly states the 700 figure and 50 figure
%% Accessible resource 700 TWh/y (page 165)
%% Practicable resource 50 TWh/y
%% Here is where the 700 comes from:
%% a) Larger figure 70 (rather than 40)
%% b) No losses at all.
%% 70kW/m x 10**6 m = 70GW = 600 TWh/y. = 24 kWh/d each
\item[Tyndall]
% Table \ref{tab.tynd}
% 3.3.2 Tyndall Centre  renewable energy and CHP resources
%shows the
% The Tyndall Centre's estimates of renewable energy resources.
The Tyndall Centre's estimate of
the total practicable renewable-energy
resource is 15\,kWh per day per person.
\item[IAG]
% \Tabref{tab.iag} shows
The
% Government's
Interdepartmental Analysts Group's estimates
of renewables, take into account economic
constraints.
Their total practical {\em{and}\/} economical resource (at a retail price of
7p/kWh) is 12\,kWh per day per person.
\item[PIU]
% \Tabref{tab.dtipiu} shows figures from the DTI's contribution to the PIU review in 2001.
The ``PIU'' column
shows the
``indicative resource potential for
renewable electricity generation options''
from the DTI's contribution to the PIU review in 2001.
For each technology I show their ``practical maximum,'' or,
if no practical maximum was given, their ``theoretical maximum.''
\item[CAT]
% All these numbers are summarized in \figref{fig.TynPiu}, along with
The final column shows
the numbers from the Centre for Alternative Technology's
``Island Britain'' plan \citep{CATzcb}.\nlabel{pCAT}\nocite{CATzcb}
% for 2027. Zero carbon britain Helweg Larsen
\end{description}
% I conclude that
% see also
% http://hwj.oxfordjournals.org/cgi/content/full/62/1/28
% I have lost the reference for this:::
\subsection{Bio-powered Europe}
Sometimes people ask me ``surely we used to live
on renewables just fine, before the Industrial Revolution?''
Yes, but don't forget that two things were different then:
lifestyles, and population densities.
Turning the clock back more than 400 years,
\ind{Europe} lived almost entirely on sustainable sources:
mainly wood and crops, augmented by a little wind power,
tidal power, and water power.
It's been estimated that the average person's lifestyle consumed
a power of 20\,kWh per day.\nlabel{pMalanima06}
% wood has 5 kWh/kg of embodied energy or 4.4 or 9.3GJ/t if wet or 3kWh/kg
The wood used per person was 4\,kg per day, which required 1 hectare
(10\,000\,m$^2$) of forest per person.
% (a power density of 0.03\,\Wmm). (NB slight mismatch between wood weight
% and energy.
The area of land per person in Europe in the 1700s
was 52\,000\,m$^2$.\index{history}\index{Middle Ages}
In the regions with highest population density,
the area per person was 17\,500\,m$^2$ of arable land, pastures,
and woods.
Today the area of Britain per person is just 4000\,m$^2$, so even
if we reverted to the lifestyle of the Middle Ages and completely
forested the country, we could
no longer live sustainably here. Our population density is far too high.
% In 1750, each person in europe needed 1.75 ha for their vegetable sources.
%(arable land, pastures, and woods)
%17500 m$^2$ per person.
%In the 17th C, Maximum population density in europe was 60 per sq km of arable land
%(17\,000\,m$^2$ per person)
\section{Green ambitions meet social reality}
Figure \ref{fig.halftime} is bleak news.
Yes, technically, Britain has ``huge'' renewables.
But realistically, I don't think Britain can live on its own renewables --
at least not the way we currently live.
\begin{figure}
\figuremargin{
\begin{center}
\begin{tabular}{@{}cl}
%{\small\sc Consumption}& {\small\sc Production}\\
{\mbox{\epsfbox{metapost/stacks.289}} }& \hspace*{19mm}\\
\end{tabular}
\end{center}
}{
\caption[a]{The state of play after we add up all the
traditional renewables, {\em and then have a public consultation.}
\vspace{1.4215in}\par
\makebox[58mm][r]{%
\begin{minipage}{83mm}
\begin{center}
\begin{tabular}{@{}cl}
%{\small\sc Consumption}& {\small\sc Production}\\
\multicolumn{2}{@{}c}{\mbox{\epsfbox{metapost/stacks.990}} }\\
\end{tabular}
\end{center}
{{\em After the public consultation.}
I fear the maximum Britain would ever get from renewables is
in the ballpark of \OliveGreen{18\,kWh/d per person}.
(The left-hand consumption number, \Red{\europe\,kWh/d per person},
by the way, is the average British consumption, excluding
imports, and ignoring solar energy acquired through
% during
% in the process of
food production.)
}
\end{minipage}}
} \label{fig.halftime2} \label{fig.halftime3}
}
\end{figure}
I am partly driven to this conclusion by the chorus
of opposition that greets any major renewable energy proposal.
People love renewable energy, {\em{unless it is bigger than a figleaf}}.
If the British are good at one thing, it's saying ``no.''\index{saying no}
\begin{whingelist}
\item[{\Windfarm}s?]
% across the country?
``No, they're ugly noisy things.''
% \marginfig{
% \begin{center}
% \begin{tabular}{@{}c@{}}
% % {\mbox{\epsfxsize=53mm\epsfbox{../../images/wicker_turbineL.eps}}} \\
% \end{tabular}
% \end{center}
% \caption[a]{A consultation exercise in full swing.
% Photo from Penicuik Environment Protection Association.
% http://www.pepawind.org.uk/
% Sat 26/1/08 requested permission DENIED
% }
%\label{wickerwindmill}
%}
\item[Solar panels on roofs?]
``No, they would spoil the visual amenity
of the street.''
\item[More forestry?]
``No, it ruins the countryside.''
\item[Waste incineration?]
``No, I'm worried about health risks, traffic congestion, dust and
noise.''
\item[Hydroelectricity?]
``Yes, but not {\em{big}\/} hydro -- that harms the environment.''
\item[Offshore wind?] ``No, I'm more worried about the ugly powerlines coming
ashore than I was about a \ind{Nazi invasion}.''\nlabel{pNazi1}
% And I don't want to pay 150\% extra for my electricity
% anyway.''
\item[Wave or geothermal power?] ``No, far too expensive.''
\end{whingelist}
After all these objections, I fear that the maximum Britain would
ever get from renewables would be something like what's
shown in the bottom right of \figref{fig.halftime3}.%
\begin{figure}[btp]
\figuremargin{
\begin{center}
%% method:
% png2ps villages.png villages.png.eps
% 120mm is textwidth
\lowres%
{\epsfig{width=70.125mm,file=../../images/PUBLICDOMAIN/maps/villages.png.eps}}%
{\epsfig{width=70.125mm,file=../../images/PUBLICDOMAIN/maps/villages.eps}}%
\end{center}
}{
\caption[a]{Where the wild things are.
One of the grounds for objecting to {\windfarm}s is
the noise they produce.
I've chopped out of
this map of the British mainland
a 2-km-radius exclusion zone surrounding
every hamlet, village, and town.
% listed in the
% \url{openstreetmap} database.
% http://www.openstreetmap.org/
These white areas would presumably be excluded
from {\windhfarm} development.
% The remaining black areas are regions where
% a proposal to erect
% wind turbines would have a chance of
% evading one of the British public's objections.
The remaining
black areas would perhaps also be largely excluded
because of the need to protect tranquil places
from industrialization.
Settlement data from
\myurl{www.openstreetmap.org}.
%% license is attribute, share alike
}
\label{fig.villages}
}
\end{figure}
\Figref{fig.villages} offers guidance to anyone trying to erect
{\windfarm}s in Britain. On a map of the British mainland I've shown in
white a 2-km-radius exclusion zone surrounding every hamlet, village,
and town. These white areas would presumably be excluded from
wind-farm development because they are too close to the humans. I've
coloured in black all regions that are {\em more than 2 km\/} from
any human settlement. These areas are largely excluded from
wind-farm development because they are {\em tranquil}, and it's
essential to protect tranquil places from industrialization. If you
want to avoid objections to your {\windfarm}, pick any piece of land
that is not coloured black or white.
% this is for TROUBLESOME FIGURE SHOWING CURRENT PRODUCTION
{
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
% \pagebreak[4]
\myquote{
% We have some environmental lobbyists who seem to be opposed to things we need to do,
% ' he sighs. '
Some of these environmentalists who have good hearts but
confused minds are almost a barrier to tackling climate change.
% `It is the duty of a sensible NGO supported by
% theprojectsthat occasionally they seeking
% to public and (are) not always say yes
% the comfort zone of saying no to a barrage, no to a {\windfarm}, no to this, no to that'. He said the RSPB was `clearly
% Renew175.pdf
% Historically that will turn out to be sad.
% 'I find it genuinely disappointing and sad that some organisations seem to put their hatred of nuclear above their concern for global warming.'
}{
% http://www.guardian.co.uk/business/2008/jun/22/utilities.oil
% Malcolm Hunt Wicks
Malcolm Wicks, Minister of State for Energy\index{Wicks, Malcolm H.}
}
\begin{figure}
\figuremargin{
\begin{center}
\begin{tabular}{@{}c}
% {\sc Consumption}& {\sc Production}\\
{\mbox{\epsfbox{metapost/stacks.2007}} }\\
\end{tabular}
\end{center}
}{
\caption[a]{Production of renewables and nuclear energy in the UK in 2006.
All powers are expressed per-person, as usual.
The breakdown of the renewables
on the right hand side is scaled up 100-fold
vertically.
% compared with all the other diagrams in this book.
}
\label{fig.current}
}
\end{figure}
%\section{About part II}
We are drawing to the close of Part I. The
assumption was that we want to get off fossil
fuels, for one or more of the reasons listed in \chref{ch.preface} --
climate change, \index{security of energy supply}security of supply,
and so forth.
\Figref{fig.current} shows how much power we currently get from
renewables and nuclear. They amount to just 4\% of our total
power consumption.
The two conclusions we can draw from Part I are:
\begin{enumerate}
\item
{\em{To make a difference, renewable facilities have to be country-sized.}}
For any renewable facility to make a contribution comparable to our
current consumption, {\em it has to be country-sized}.
To get a big contribution from wind, we used {\windfarm}s with the area of Wales.
To get a big contribution from solar photovoltaics, we
\amargintab{t}{
\renewcommand{\W}{\,\Wmm}
\begin{tabular}{@{\,}lr@{\,}} \toprule
\multicolumn{2}{c}{\OliveGreen{\sc{Power per unit land }}}\\
\multicolumn{2}{c}{\OliveGreen{\sc{or water area}}}\\
\midrule
Wind &\OliveGreen{ 2\W} \\
Offshore wind &\OliveGreen{ 3\W} \\
Tidal pools &\OliveGreen{ 3\W} \\
Tidal stream &\OliveGreen{ 6\W} \\
%%% Raw sunshine (UK) &\OliveGreen{50\W} \\
Solar PV panels &\OliveGreen{ 5--20\W} \\
Plants &\OliveGreen{ 0.5\W} \\
Rain-water\\
\ (highlands)
&\OliveGreen{ 0.24\W} \\
Hydroelectric \\
\ facility
&\OliveGreen{ 11\W} \\
Geothermal
&\OliveGreen{ 0.017\W} \\
\bottomrule
\end{tabular}
\caption[a]{
% To make a difference, renewable facilities have to be country-sized.
Renewable facilities have to be country-sized
because all renewables are so diffuse.\index{power density!all renewables}
}\label{figW2a}
}%
required half the area of Wales.
To get a big contribution from waves, we imagined {\wavefarm}s covering
500\,km of coastline.
To make energy crops with a big contribution, we took 75\% of the whole country.
Renewable facilities have to be country-sized
because all renewables are so diffuse\index{power density!all renewables}.
\Tabref{figW2a} summarizes most of the powers-per-unit-area that we encountered
in Part I.
To sustain Britain's lifestyle on its renewables alone
would be very difficult.
A renewable-based energy solution will necessarily be large and intrusive.
\item
{\em It's not going to be easy\/} to make a plan that adds
up using renewables alone.
If we are serious about getting off fossil fuels,
Brits are going to have to learn to start saying ``yes'' to something.
Indeed to several somethings.
\end{enumerate}
In Part II
I'll ask, ``assuming that we can't get production from renewables to
add up to our current consumption,
what are the other options?''
\beginfullpagewidth
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pUKAV}]
{\nqs{UK average energy consumption
is \europe\,kWh per day per person.
}}
% 2870\,TWh,
% 48 649.8 / person /year
% The total energy consumption statistic includes petroleum, dry natural gas, coal, net hydro, nuclear, geothermal, solar, wind, wood and waste electric power. The renewable energy consumption statistic is based on International Energy Agency (IEA) data and includes hydropower, solar, wind, tide, geothermal, solid biomass and animal products, biomass gas and liquids, industrial and municipal wastes.
% ``of which nuclear was 11%'' (and nuclear was ``23% of elec'')
% and electricity was 346.1 billion kilowatt hours (2003)
% ie 15.8 kWh/d per person which would make nuclear 3.63
% on the other hand when we say 133*0.11 we get 14.65
% 60,441,457 popn in 2005
I took this number from the UNDP Human Development Report, 2007.
The DTI (now known as DBERR) publishes a
Digest of United Kingdom Energy Statistics every year.
% \myurl{www.dti.gov.uk/energy/inform/dukes/}
\tinyurl{uzek2}{http://www.dti.gov.uk/energy/inform/dukes/}.
In 2006,
according to DUKES,
total primary energy demand was
% 1½ per cent lower in 2006 than in 2005 at
244 million
% the primary supply of fuels was 243.8 million
\tonnes\ of oil equivalent,
which corresponds to 130\,kWh per day per person.
% 244 * 11630 / 365 / 60
% Primary demand is 247.3\,Mtoe. in 2005?
% (Of which about 1.5\% is lost in distribution.)
%
%\myurl{http://www.eia.doe.gov/emeu/cabs/United_Kingdom/Full.html}
%says 2003 consumption was 133\,kWh/d per person.
I don't know the reason for the small difference between
the UNDP number and the DUKES number, but I can explain why
I chose the slightly lower number. As I mentioned on \pref{pDUKES},
DUKES uses the same energy-summing convention as me,
declaring one kWh of chemical energy to be equal to one kWh
of electricity. But there's one minor exception:
DUKES defines the ``primary energy'' produced
in nuclear power stations to be the thermal energy, which in
2006 was 9\,kWh/d/p; this was converted (with 38\% efficiency) to
3.4\,kWh/d/p of supplied electricity; in my accounts,
I've focused on the electricity produced by hydroelectricity, other
renewables, and nuclear power; this small switch
in convention reduces the nuclear contribution
% to the total primary production
by about 5\,kWh/d/p.
% eg DUKES page 133
% fuel used in generation - nuclear - 2006 - 17.131 Mtoe 9.097 kWh/d/p
% hydro - .32 Mtoe 0.17 kWh/d/p
% cf BP, UK hydro (2007 in review) says 1.9, 2.1 Mtoe for 06,07 FAR bigger!
% BP nuclear 17.1,14.1
% bizarre!
% BP say primary energy consumption of UK was 224.4, 215.9 in 06,07
\item[\npageref{pLosses}]
{\nqs{%
Losses in the electricity transmission network
chuck away 1\% of total national energy consumption}}.
To put it another way, the losses are
% Electricity demand total: 402\,TWh.
% page 68 of xpdf ../../refs/DTIDigest.pdf
8\% of the electricity generated.\index{transmission losses}\index{electricity grid!losses}\index{grid!losses}\index{loss!transmission losses}\index{national grid!transmission losses}\index{electricity!losses}\index{power line losses}
This 8\% loss can be broken down: roughly 1.5\% is lost in
the long-distance high-voltage\index{long-distance electricity transmission}
system, and 6\% in the local public supply system.
% Energy industry itself used 8\% of electricity.
Source: \cite{Dukes07}.
\item[\npageref{fig.En2}]
{\nqs{Figure \ref{fig.En2}.}}
% and \ref{fig.En2}}}.
Data from UNDP Human Development Report, 2007.
\tinyurl{3av4s9}{http://hdr.undp.org/en/statistics/}
\item[\npageref{pMalanima06}]
{\nqs{In the Middle Ages, the average person's lifestyle consumed
a power of 20\,kWh per day.
}}
Source: \cite{Malanima06}.
\item[\npageref{pNazi1}]
{\nqs{``I'm more worried about the ugly powerlines coming
ashore than I was about a \ind{Nazi invasion}.''}}
Source: \tinyurl{6frj55}{http://news.independent.co.uk/environment/article2086678.ece}.
\end{notelist}
\normalsize
\ENDfullpagewidth
% today's renewables
% 2007
% http://www.restats.org.uk/statistics_national.htm
% 79% of renewable -> electricity
% Total elec gen'd was 19,664 GWh 0.89 kWh/d
% Around 485 million litres of biodiesel were produced in the UK in 2007
% 347 million litres of biodiesel were consumed in 2007. around 138 million litres of biodiesel were exported in 2007.
% 153 million litres of bioethanol was consumed in the UK in 2007, up from 95 million litres in 2006, and 85 million litres in 2005. Only one UK plant was in production in 2007, and so the majority of the bioethanol was imported.
}% END this is for TROUBLESOME FIGURE SHOWING CURRENT PRODUCTION
% \input{summary1.tex}
\dvipsb{part one - Numbers, not adjectives}
\cleardoublepage
\bset\part{\bcol{Making a difference}}%%
\bset\chapter{\bcol{Every BIG helps}}
\label{ch.everyBIG}
%% \part{Making a difference}%%
%% introduction to part III no 2
\marginfig{\small
\begin{center}
\begin{tabular}{p{50mm}}
\mbox{\epsfxsize=50mm\epsfbox{../../images/cartoon/NPS0bCC.jpg.eps}} \\
{\em{``We were
going to have a wind turbine
but they're not very efficient''}} \\
\end{tabular}
\end{center}
\caption[a]{
Reproduced by kind permission of PRIVATE EYE /
Robert Thompson
% cartoon from Private Eye April 2007.
% Fri 27/4/07
\url{www.private-eye.co.uk}.
}\label{PrivEyeWind}
}%
% What now?
%
We've established that the UK's present lifestyle can't
be sustained on the UK's own renewables (except
with the industrialization of country-sized
areas of land and sea).
So, what are our options, if we wish to get off fossil fuels and
live sustainably?
We can balance the energy budget
% of a country like Britain
either by reducing demand, or by increasing supply,
or, of course, by doing both.
Have no illusions. To achieve our goal
of getting off fossil fuels, these reductions in demand and increases in
supply must be {\em{big}}. Don't be distracted by the myth that
``every little helps.'' {\em If everyone does a little, we'll achieve only
a little.}
We must do a lot.
% In part II we'll discuss how to get everyone to do a lot.
% The best ways of getting preferably without
What's required are {\em{big}\/} changes in demand and in supply.
``But surely, if 60 million people all do a little,
it'll add up to a lot?''
% \section{The `if-everyone' multiplication}
No. This ``if-everyone'' multiplying machine
is just a way of making something {{small}\/} {\em{sound}\/} {{big}}.
The ``if-everyone'' multiplying machine churns out inspirational
statements of the form
``if {\em{everyone}\/} did X, then it would provide enough energy/water/gas
to do {{Y}},'' where Y sounds impressive.
Is it surprising that Y sounds big?
Of course not. We got Y by multiplying
X by the number of people involved -- 60 million or so!
Here's an example from the \ind{Conservative Party}'s otherwise
straight-talking
{\em{Blueprint for a Green Economy}}:
\begin{quote}
``The mobile phone charger
averages around \ldots 1\,W consumption, but if every one of the country's 25 million mobile phones
chargers were left plugged in and switched on they would consume enough electricity (219\,GWh) to
power 66\,000 homes for one year.''
\end{quote}
66\,000? Wow, what a lot of homes! Switch off the chargers!
66\,000 sounds a lot, but the sensible thing to compare it with
is the total number of homes that we're imagining would
participate in this feat of conservation, namely {\em{25 million}\/} homes.
66\,000 is
just {\em{one quarter of one percent}\/}
of 25 million.
So while the statement quoted above is true, I think a calmer way to put
it is:
\begin{quote}
If you leave your mobile phone charger
plugged in, it uses \MidnightBlue{one quarter of one percent} of your home's electricity.
\end{quote}
And if everyone does it?
\begin{quote}
If {\em{everyone}\/} leaves their mobile phone charger
plugged in, those chargers will use
\MidnightBlue{one quarter of one percent} of their homes' electricity.
\end{quote}
The ``if-everyone'' multiplying machine is a {{bad thing}\/} because
it deflects people's attention towards
25 million minnows instead of 25 million sharks.
The mantra {\em ``Little changes can make a big difference''}
is bunkum, when applied to climate change and power.
It may be true that ``many people doing a little adds up to a lot,''
if all those ``littles'' are somehow focused into a single ``lot'' --
for example, if one million people donate \pounds10 to {\em{one}\/}
accident-victim, then the victim receives \pounds10 million. That's a lot.
But power is a very different thing. We all use power. So to achieve
a ``big difference'' in total power consumption, you need almost
everyone to make a ``big'' difference to their own power
consumption.
% Books that discuss how to fix the energy problem often end with an
% enormous shopping list of inspiring ideas.
So, what's required are {\em{big}\/} changes in demand and in supply.
Demand for power could be reduced in three ways:
\ben
\item
by reducing our population (\figref{fig.Popul});\index{population reduction}
\marginfig{
\mywquote{While the footprint of each individual cannot be reduced to zero,
the absence of an individual does do so.}%
{\index{Rapley, Chris}{Chris Rapley}, former Director of \par \hfill
the British Antarctic Survey}
% \myurl{http://www.belfasttelegraph.co.uk/features/daily-features/article2715156.ece}
\mywquote{We need fewer people, not greener ones.}%
{Daily Telegraph, 24 July 2007}% , 24/7/2007}
\mywquote{Democracy cannot survive overpopulation. Human
dignity cannot survive overpopulation.}%
{\ind{Isaac Asimov}}
%\begin{figure}
%\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ChildEmissions.eps}}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{Population growth and emissions\ldots\index{population growth}
% Cartoon from New Scientist.
Cartoon courtesy of Colin Wheeler.
}\label{fig.Popul}
}
% \end{figure}
% you need to control your emissions
\item
by changing our lifestyle;
\item
by keeping our lifestyle, but reducing its \ind{energy intensity}
through ``\ind{efficiency}'' and ``\ind{technology}.''
\een
%
Supply could be increased
% above the limits of renewables
in three ways:
\ben
\item
We could get off fossil fuels by
investing in ``clean coal'' technology.
Oops! Coal is a fossil fuel.
Well, never mind -- let's take a look at this idea.
If we used coal ``sustainably'' (a notion we'll define in a moment),
how much power could it
offer? If we don't care about sustainability and
just want ``security of supply,'' could coal offer that?
\item
We could invest in nuclear fission.
Is current nuclear technology ``sustainable''? Is it at least
a stop-gap that might last for 100 years?
\item
We could buy, beg, or steal renewable energy from other countries -- bearing
in mind that most countries will be in the same boat as Britain
and will have no renewable energy to spare; and also
bearing in mind that sourcing renewable energy from another country
doesn't magically shrink the renewable power facilities
required.
%% to deliver power comparable to Britain's needs.
If we import renewable energy from other countries in order to avoid
building renewable facilities the size of Wales in {\em{our}\/} country,
% we must have no illusions: we
someone will have to build facilities
roughly the size of Wales in those other countries.
\een
% The next chapters address the `efficiency' and `technology'
% options on the demand side.
The next seven chapters discuss first how to reduce demand
substantially,
and second how to increase supply to meet that reduced, but still ``huge,''
demand.
% TBC CHECK seven is right *** YES.
%
% Once we've figured out by how much demand can plausibly be reduced,
% we can then turn back to the supply side, and quantify how much
% energy we need to get from nuclear power, or from other people's
% renewables, if we want to get off fossil fuels and live sustainably.
%
In these chapters, I won't mention {\em{all}\/} the good ideas.
I'll discuss just the {\em{big}\/} ideas.
% \vfillone
\section{Cartoon Britain}
\index{cartoon Britain}To
simplify and streamline our discussion of demand reduction,
I propose to work with a cartoon of British energy consumption, omitting
lots of details in order to focus on the big picture.
% Here's how my cartoon works.
My cartoon-Britain consumes energy in just three forms:
heating, transport, and electricity.
The heating consumption of \ind{cartoon-Britain}
is 40\,kWh per day per person
(currently all supplied by fossil fuels);%
%\begin{figure}
% \figuremargin{
\amarginfig{t}{
\begin{tabular}{@{}c@{}}
\mbox{\epsfbox{metapost/stacks.799}}\\
\end{tabular}
% }{
\caption[a]{Current consumption in
``cartoon-Britain 2008.''\index{cartoon-Britain!2008}
}
}
%\end{figure}
the transport consumption is also 40\,kWh per day per person
(currently all supplied by fossil fuels);
and the electricity consumption is
18\,\kWhe\ per day per person;
the electricity is currently
almost all generated from fossil fuels; the conversion
of fossil-fuel energy to electricity is 40\% efficient,
so supplying 18\,\kWhe\ of electricity in
today's cartoon-Britain requires
a fossil-fuel input of 45\,kWh per day per person.
This simplification ignores some fairly sizeable details,
such as agriculture and industry, and the embodied energy of imported goods!
% could refer to fig {fig.OfficialBreakdown}
But I'd like to be able to have a {\em{quick}\/}
conversation about the main things we need to do to get off
fossil fuels.
Heating, transport, and electricity account for more than half of
our energy consumption, so if we can come up with a plan that delivers
heating, transport, and electricity sustainably, then we have made a
good step on the way to a more detailed plan that adds up.
Having adopted this cartoon of Britain, our discussions of
demand reduction will have just three bits.
First,
how can
we reduce transport's energy-demand and eliminate all fossil fuel use
for transport?
This is the topic of \chref{ch.smarttr}.
Second,
how can we reduce heating's energy-demand and eliminate all fossil fuel use
for heating?
This is the topic of \chref{ch.smarth}.
Third, what about electricity? \Chref{ch.smarte} discusses efficiency in
electricity consumption.
Three supply options -- clean coal, nuclear, and other people's renewables --
are then discussed in Chapters \ref{ch.sff},
\ref{ch.fusion}, and
\ref{ch.international}. Finally, \chref{ch.storage}
discusses how
to cope with fluctuations in demand and fluctuations in renewable
power production.
Having laid out the demand-reducing and supply-increasing
options, Chapters \ref{chaplan} and \ref{ch.costs} discuss various ways
to put these options together to make plans that add up,
in order to supply cartoon-Britain's transport, heating, and electricity.
% If all the things on such a list are {\em{little}},
% however, then they won't add up to a
I could spend many pages discussing ``50 things you can do to make a
difference,'' but I think this cartoon approach, chasing the three biggest
fish, should lead to more effective policies.
But what about ``stuff''? According to Part I,
the embodied energy in imported stuff might be the
biggest fish of all! Yes, perhaps that fish is the mammoth in the
room.
% But apart from buying less stuff, or applying import tariffs
% to imports of embedded energy, there's not much that
But let's leave defossilizing that mammoth
to one side, and focus on the animals over which we have
direct control.
So, here we go: let's talk about
transport, heating, and electricity.
% and we are going to attack them first on the demand side
% and then on the supply side.
\section{For the impatient reader}
Are you eager to know the end of the story right away?
Here is a quick summary, a sneak preview of Part II\@.
First, we electrify transport. Electrification
both gets transport off fossil fuels, and makes transport more energy-efficient.
(Of course, electrification increases our demand for
green
% sustainable
electricity.)
Second, to supplement solar-thermal heating, we electrify
most heating of air and water in buildings
using {\em heat pumps}, which
are four times more efficient than
% simple resistance-heaters.
ordinary electrical heaters.
This electrification of heating further increases the amount of
green electricity required.
Third, we get all the green electricity from a mix of four sources:
from our own renewables; perhaps from ``clean coal;'' perhaps from nuclear; and
finally, and with great politeness, from other countries' renewables.
Among other countries' renewables,
solar power in deserts is the most plentiful option.
As long as we can build peaceful international collaborations,
solar power in other people's deserts certainly has the technical
potential to provide us, them, and everyone with 125\,kWh per day per person.
Questions? Read on.
% \newpage
%\noindent
%\mbox{\epsfbox{metapost/stacks.10}}
% \chapter{Reflections on sustainable production}% -- the total}
%\chapter{Sustainable production -- the total}
%\input{total.tex} nothing here
%\input{population.tex}
% \chapter{Summary of part I}
% \part{Technology}
%\part{Transport technology}
\bset\chapter{\bcol{Better transport}}%{Transport technology}
\label{ch.smarttr}
\label{ch.transport}
\myquote{%
Modern vehicle technology can reduce climate change emissions without changing the look, feel
or performance that owners have come to expect.
}{California Air Resources Board}
%\end{quote}
Roughly one third of our energy goes into transportation.
Can {\em{technology}\/}
deliver a reduction in consumption?
\marginpar[b]{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Train_wreckS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Train_wreck_at_Montparnasse_1895.jpg.eps}}}
\\
\end{tabular}
\end{center}
% \caption[a]{ }
\label{ptrainwreck}
}%
In this chapter we explore options
for achieving two goals: to deliver the biggest possible
reduction in transport's energy use, {\em{and}\/} to eliminate
fossil fuel use in transport.
% Electric cars.
% Switching freight from road to rail.
% Integrated public transport.
% Magnetic levitation.
% More-efficient planes.
% Do any of these ideas add up?
Transport featured in three of our consumption chapters:
\chref{ch.cars} (cars), \chref{ch.air} (planes), and \chref{ch.freight} (road freight
and sea freight). So there are two sorts of transport to address:
passenger transport, and freight.
Our unit of passenger transport is the \ind{passenger-kilometre} (\ind{p-km}).
If a car carries one person a distance of 100\,km, it delivers 100\,p-km
of transportation. If it carries four people the same distance,
it has delivered 400\,p-km.
Similarly our unit of freight transport is the \ind{ton-km} (\ind{t-km}).
If a truck carries 5\,t of cargo a distance of 100\,km then
it has delivered 500\,t-km of freight-transport.
% To recap the units
We'll measure the energy consumption of
passenger transport in ``kWh per 100 passenger-kilometres,''
and the energy consumption of freight in
``kWh per ton-km.''
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Lexus1S.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Lexus1.jpg.eps}}}\\
%\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Lexus2S.jpg.eps}}}%
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/Lexus2.jpg.eps}}}\\
%% Lexus RX300
\end{tabular}
\end{center}
\caption[a]{
This chapter's starting point: an urban luxury tractor.
The average UK car has a fuel consumption of 33 miles per gallon,
which corresponds to an energy consumption of \eccol{80\,kWh per 100\,km}.
Can we do better?
}\label{fig.lexus}
}%
Notice that these measures are the other way up compared to
``miles per gallon'': whereas we like vehicles to deliver
{\em{many}\/} miles per gallon,
we want energy-consumption to be {\em{few}\/}
kWh per 100\,p-km.
We'll start this chapter by
discussing how to reduce the
energy consumption of surface transport.
To understand how to reduce energy consumption, we need to
understand where the energy is going in surface transport.
Here are the three key concepts, which
are explained in more detail in Technical \appref{ch.cars2}.
\begin{enumerate}
\item
In {\em{short-distance travel}} with lots of starting and stopping,
the energy mainly goes into speeding
up the vehicle and its contents.
Key strategies for consuming less in this sort of transportation
are therefore to {\em{weigh less}}, and to {\em{go further between stops}}.
Regenerative braking, which captures energy when slowing down, may help too.
In addition, it helps to {\em{move slower}}, and to {\em{move less}}.
\item
In {\em{long-distance travel}\/} at steady speed,
by \ind{train} or \index{car}{automobile}, most
of the energy goes into making air swirl around, because
you only have to accelerate the vehicle once.\index{air resistance}\index{drag}
The key strategies for consuming less in this sort of transportation
are therefore to {\em{move slower}}, and to {\em{move less}}, and to {\em{use long, thin
vehicles}}.
\item
In all forms of travel, there's an energy-conversion chain, which takes
energy in some sort of fuel and uses some of it to push the vehicle forwards.
Inevitably this energy chain has inefficiencies. In a standard fossil-fuel
car, for example,
only 25\% is used for pushing, and\index{petrol engine!efficiency}\index{engine!exhaust}
roughly 75\% of the energy is lost in making the \ind{exhaust}, engine,
and \ind{radiator} hot.
So a final strategy for consuming less energy is to make the energy-conversion
chain more efficient.
\end{enumerate}
These observations lead us to six principles of vehicle
design and vehicle use for more-efficient
surface transport:\index{transport!efficiency measures}
\begin{inparaenum}[\itshape a\upshape)]
% \begin{itemize}
\item
reduce the frontal area per person;
\item
reduce the vehicle's weight per person;
\item
when travelling, go at a steady speed and avoid using brakes;
\item
travel more slowly;
\item
travel less; and
\item
make the energy chain more efficient.
%\end{itemize}
\end{inparaenum}
We'll now discuss a variety of ways to apply these principles.
\section{How to roll better}
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/cambluefront2c.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{Team Crocodile's \ind{eco-car} uses
\eccol{1.3\,kWh per 100\,km}.
Photo kindly provided by \ind{Team Crocodile}.
\myurlb{www.teamcrocodile.com}{http://www.teamcrocodile.com/}
}\label{fig.ecocar}
}%
A widely quoted statistic says something along the lines of
``only {\em 1 percent\/} of
the energy used by
a car goes into moving the driver\nlabel{p1percent}''
-- the implication being that, surely, by being a bit smarter, we could
make cars {\em 100\/} times more efficient?
The answer is yes, almost, but only by applying
the principles of vehicle design and vehicle use,
listed above, to {\em{extreme}\/} degrees.
% eco car ecocar
One illustration of extreme vehicle design
is an \ind{eco-car}\index{car!eco-car}, which
has small frontal area and low weight, and -- if any records are to
be broken -- is carefully driven at a low and steady speed.
%% http://www.shell.com/home/content/uk-en/society_environment/eco_marathon/results/2007_eco_marathon_leader_board.html
%% 2184 mpg at 15 mph which is 6.7 m/s or 24.14 km/h
%% In 2007 they did 2082, and had 2 valid runs out of 4.
The {\em Team Crocodile\/} eco-car
(\figref{fig.ecocar})
does 2184 miles
per gallon (\eccol{1.3\,kWh per 100\,km})\index{transport!efficiency!eco-car}
at a speed of 15\,mph (24\,km/h).
% 15 miles per hour.
Weighing 50\,kg and shorter in height than a traffic cone,
it comfortably accommodates one
teenage driver.
%% 773.149199 km per litre
%% 10 kWh per 773 pkm , which is 1.3 kWh per 100 pkm
%To achieve this performance, the driver must be careful to drive at steady speed.
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/ChristianaBikeS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ChristianaBike.eps}}}\\
\end{tabular}
\end{center}
\caption[a]{
``Babies on board.''\index{bicycle}
This mode of transportation has an\index{transport!efficiency!bicycle}
energy cost of \eccol{1\,kWh per 100 person-km}.
}\label{fig.cbike}
}%
Hmm. I think that the driver of the
\ind{urban tractor}\index{tractor} in \figref{fig.lexus} might detect a
change in ``look, feel and performance'' if we
switched them to the eco-car and
instructed them to keep their speed below 15 miles per hour.
So, the idea that cars could easily be 100 times more energy efficient
is a myth.\index{myth!car inefficiency} We'll come back to the challenge of
making energy-efficient cars in a moment.
But first, let's see some other ways of satisfying the principles of
more-efficient surface transport.
\Figref{fig.cbike} shows a multi-passenger vehicle that is
%Here are two other extreme vehicle designs which are
at least
25 times more energy-efficient than
a standard petrol car:
a \ind{bicycle}.\index{transport!efficiency!bicycle}
The bicycle's performance (in terms of
energy per distance) is about the same as the eco-car's.\nlabel{pBikeS} Its speed
is the same, its mass is lower than the eco-car's (because the
human replaces the fuel tank and engine), and its effective frontal
area is higher, because the cyclist is not so well streamlined as
the eco-car.
\Figref{fig.stoptrain} shows another possible replacement%
\marginfig{
\begin{center}
\begin{tabular}{c}
\lowres{\epsfxsize=50mm\epsfbox{../../images/StoppingTrain2CS.jpg.eps}}%
{\epsfxsize=50mm\epsfbox{../../images/StoppingTrain2C.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
This 8-carriage
% stopping
train,\index{rail}
% from Cambridge to London,
at its maximum speed of 100\,mph (161\,km/h),
consumes\index{transport!efficiency!train}
\eccol{1.6\,kWh per 100 passenger-km}, if full.
}\label{fig.stoptrain}\label{pLST}
}
for the petrol car: a \ind{train}, with an
energy-cost, if full, of \eccol{1.6\,kWh per 100 passenger-km}.
In contrast to the eco-car and the bicycle,
\ind{train}s manage to achieve outstanding efficiency
without travelling slowly, and without having a low weight per person.
Trains make up
for their high speed and heavy frame by exploiting the
principle of small \ind{frontal area}\index{area!frontal}
per person. Whereas a cyclist and a regular car have effective frontal areas of
about 0.8\,m$^2$ and 0.5\,m$^2$ respectively, a full commuter \ind{train} from
Cambridge to London
has a frontal area per passenger of
% 2.8*4 / 630
0.02\,m$^2$.
% 0.01778
But whoops, now we've broached an ugly topic -- the prospect of
sharing a vehicle with ``all those horrible people.''
Well, squish aboard, and let's ask:
How much could consumption be reduced by
a switch from personal gas-guzzlers to excellent
integrated public transport?
\begin{figure}[hbtp]
\figuremargin{\small
%\begin{center}
\begin{tabular}{@{}lc@{}}
\begin{tabular}{@{}c@{\,\,}c@{}}
\mbox{\epsfysize=29mm\lowres{\epsfbox{../../images/TubeTrainSS.jpg.eps}}%
{\epsfbox{../../images/TubeTrainS.jpg.eps}}}%
&
\mbox{\epsfysize=29mm\lowres{\epsfbox{../../images/TubeTrainIntSS.jpg.eps}}%
{\epsfbox{../../images/TubeTrainIntS.jpg.eps}}}\\
\multicolumn{2}{c}{\eccol{4.4\,kWh per 100\,\pkm}, if full} \\
\end{tabular}
\,\,
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=50mm\epsfbox{../../images/TrainsKX1.jpg.S.eps}}}%
{\mbox{\epsfxsize=50mm\epsfbox{../../images/TrainsKX1.jpg.eps}}}\\
{\eccol{3--9\,kWh per 100 seat-km}}, if full \\[2mm]
\end{tabular}
\\[2mm]
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfysize=37mm\epsfbox{../../images/MuniTrolleybusesCS.jpg.eps}}}%
{\mbox{\epsfysize=37mm\epsfbox{../../images/MuniTrolleybusesC.jpg.eps}}}\\
\eccol{7\,kWh per 100\,\pkm}, if full \\
\end{tabular}
\,\,
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfysize=37mm\epsfbox{../../images/vancouverseabusCS.eps}}}%
{\mbox{\epsfysize=37mm\epsfbox{../../images/vancouverseabusC.eps}}}
\\
\eccol{21\,kWh per 100\,\pkm}, if full \\
\end{tabular}
\\
\end{tabular} %%% end megatable
\\
%\end{center}
}{
\caption[a]{Some public transports, and their energy-efficiencies,
when on best behaviour.
Tubes, outer and inner.\index{underground rail}\index{metro}
Two high-speed trains. The electric one uses\index{high-speed train}
\eccol{3\,kWh per 100 seat-km}; the diesel, \eccol{9\,kWh}.
Trolleybuses\index{trolleybus}
in \ind{San Francisco}.\index{electric bus}\index{bus!electric}\index{trolleybus}
\ind{Vancouver} \ind{SeaBus}. Photo by Larry.
% http://lm-horizons.com/
}\label{tube}\label{IC125}\label{SeaBus}
}% end caption enclosure
\end{figure}%
\section{Public transport}
\label{chTrain}
At its best, shared public transport is far more energy-efficient than
individual car-driving.
A diesel-powered {\bf{coach}}, carrying 49 passengers and doing\index{coach}
10 miles per gallon at 65 miles per hour,
% 10kWh per litre / 10 miles per imperial gallon in kWh per km:
% 2.8 kWh / km
% 280 kWh / 100km
% 6 kWh / 100pkm
% 5.76
uses \eccol{6\,kWh per 100\,\pkm} -- 13 times better than the
single-person car.
% wiki says 3.65 kWh per mile for a 50-seater coach
% which is 4.5 kWh per 100 pkm
\ind{Vancouver}'s {\bf{trolleybuses}}
consume
% have an energy consumption of
270\,kWh per 100 vehicle-km, and have
an average speed of 15\,km/h.
% 15.2
% http://www.vcn.bc.ca/t2000bc/learning/vancouver/operating_stats.html
% further source: http://www.apta.com/research/stats/bus/powereff.cfm
% which gives 350 kWh per 100 vkm
If the trolleybus has 40 passengers on board, then its
passenger transport cost is
\eccol{7\,kWh per 100\,\pkm}.
%
The Vancouver {\bf{\ind{SeaBus}}} has a transport cost of
83\,kWh per vehicle-km at a speed of 13.5\,km/h.
It can seat 400 people, so its passenger transport cost
when full is \eccol{21\,kWh per 100\,\pkm}.
% 6.8
London {\bf{underground trains}}, at peak times,
use \eccol{4.4\,kWh per 100\,\pkm} -- 18 times better
than individual cars.\nlabel{pTube}
Even {\bf{high-speed trains}}, which violate two of
our energy-saving principles by going twice as fast as the car and weighing a lot,
are much more energy efficient:
% Imagine switching from driving 100\,km per day by
% car (which costs 80\,kWh/d)
% to riding 100\,km per day on a \ind{high-speed train}.
if the electric high-speed train is full, its energy cost
is \eccol{3\,kWh per 100\,p-km}\label{pHST} -- that's
27 times smaller than the car's!
However, we must be realistic in our planning.
Some trains, coaches, and buses are not full (\figref{fig.KXcell}).
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/TrainInterior.jpg.S.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/TrainInterior.jpg.eps}}}\\
\end{tabular}
\end{center}
\caption[a]{Some trains aren't full.
Three men and a cello -- the sole occupants
of this carriage of the 10.30 high-speed train from Edinburgh to
Kings Cross.
}\label{fig.KXcell}
}%
So the {\em{average}\/} energy cost of public transport is bigger
than the best-case figures just mentioned.
What's the {\em{average}\/}
energy-consumption of public transport systems,
and what's a realistic appraisal of how good they could be?
In 2006--7,
% For London transport, the most recent detailed energy-consumption figures I have found are
% from 1982.
% In 1982, the {\em{average}} occupancy of a London underground train
% was just 12 passengers per train, and
the total energy cost of all London's underground
trains, including lighting, lifts, depots, and workshops, was
\eccol{15\,kWh per 100\,\pkm} -- five times better than
our baseline car.
% 1982: was 70kWh Occupancy per vehicle: 11.8, distance between stops: 1.8\,km
% All London transport trains, average speed 33\,km/h (20\,mph),
% total cost
% Rail delivered 4000 million passenger km.
%
In 2006--7
% 1982, the energy cost of all London buses (with an average occupancy of
% 14 passengers per vehicle)
% average speed 18\,km/h (11\,mph)
% was \eccol{24\,kWh per 100\,\pkm}.\nlabel{pRidley}
the energy cost of all London buses
was \eccol{32\,kWh per 100\,\pkm}.\nlabel{pRidley}
%passenger-km}.
% occupancy per vehicle: 14.4, distance between stops: 0.3\,km
% Bus delivered 4000 million passenger km.
% \cite{RidleyCatling1982}
Energy cost is not the only thing that matters, of course. Passengers care about
speed: and the underground trains delivered higher speeds (an average of 33\,km/h)
than buses (18\,km/h). Managers care about financial
costs: the staff costs, per passenger-km,
of underground trains are less than those of buses.
\begin{figure}[htbp]
\figuremargin{\small
\begin{center}
\begin{tabular}{@{}cc@{}}
\begin{tabular}{@{}c}
\mbox{\epsfysize=26mm\epsfbox{../../images/PUBLICDOMAIN/Routemaster.eps}}\,
\mbox{\epsfysize=26mm\epsfbox{../../images/RedBus.eps}} \\
\eccol{32\,kWh per 100\,\pkm} \\
\end{tabular}
\,
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/SJPCroydonTramS.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/SJPCroydonTram.eps}}}
\\
\eccol{9\,kWh per 100\,p-km}\\
\end{tabular}
\\
\end{tabular} %%% end megatable
\\
\end{center}
}{
\caption[a]{Some public transports, and their
{\em{average}\/} energy consumptions.
Left:
Some red buses.
Right:
Croydon Tramlink. Photo by Stephen Parascandolo.\index{tram}
}\label{pBus}\label{CroydonTram}
}% end caption enclosure
\end{figure}%
The total energy consumption of the
\ind{Croydon Tramlink} system (\figref{CroydonTram}) in 2006--7
(including the tram depot and facilities
at tram-stops) was
% 4.4-4.6 kWh per vehicle km
\eccol{9\,kWh per 100\,p-km}, with an average speed of 25\,km/h.\nlabel{pCroy}
% 8.66 in 2006-7, see David Sterratt doc
% Siemens: the Combino tram itslf
% delivrs aout 2.83 kWh/100pkm
% (not including anything outside the motor
% itself.) see David Sterratt doc
% Croydon tramlink length of route is 28km
% Wimbledon to East Croydon takes 28mins
% Wimbledon to New Addington takes 45mins
% Wimbledon to East Croydon Tram Stop is 10.1km
% New Addington to East Croydon is 8.43km.
% So average speed Wim to New Add is 18.53/0.75 = 25\,km/h
% Stephen Parascandolo is deceased
How good could public transport be?
Perhaps we can get a rough indication by looking at the data from
{Japan} in \tabref{tab.JapPT}.
At \eccol{19\,kWh per 100\,\pkm} and
\eccol{6\,kWh per 100\,\pkm}, bus and rail
both look promising.\index{Japan!public transport}\index{public transport!Japan}
Rail has the nice advantage that it can solve both of
our goals -- reduction in energy consumption, and independence
from fossil fuels.
Buses and coaches have obvious advantages of simplicity and flexibility,
but keeping this flexibility at the same time as getting buses and coaches
to work without fossil fuels may be a challenge.
\margintab{
\begin{center}
\begin{tabular}{lr}\toprule
\multicolumn{2}{r}{Energy consumption}\\
\multicolumn{2}{r}{(kWh per 100\,\pkm)}\\
% Car Bus Rail Air Sea
% 68 19 6 51 57
\midrule
Car & 68\\
Bus & 19\\
Rail & 6\\
Air & 51\\
Sea & 57\\
\bottomrule
\end{tabular}
\end{center}
\caption[a]{Overall transport efficiencies
of transport modes in Japan (1999).
% in kWh per 100 passenger-km.
% Source?
}\label{tab.JapPT}
}%
To summarise, public transport (especially electric trains, trams, and buses) seems
a promising way to deliver passenger transportation -- better in
terms of energy per passenger-km, perhaps five or ten times better than cars.
However, if people demand the flexibility of a private vehicle,
what are our other options?
\begin{figure}
\figuremargin{
% see sbt/emissions.gnu
\begin{center}
\begin{tabular}{c}
{\mbox{\epsfxsize=110mm\epsfbox{figs/emissions.eps}}} \\
%{\mbox{\epsfxsize=110mm\epsfbox{figs/emissions.ps}}} \\
\end{tabular}
\end{center}
}{%%% histogram made by emissions.gnu
\caption[a]{Carbon pollution,
% Emissions,
in grams \COO\ per km, of
a selection of cars for sale in the \UK\@.
The horizontal axis shows the emission rate, and the
height of the blue histogram indicates the number of models on sale
with those emissions in 2006.
Source: {\tt{www.newcarnet.co.uk}}.
The second horizontal scale indicates approximate energy consumptions,
assuming that 240\,g\,\COO\ is associated with 1\,kWh of chemical energy.
}
\label{fig.emissions}
}
\end{figure}
\section{Private vehicles: technology, legislation, and incentives}
% \subsection{How to ensure choosers make the right choice?}
The energy consumption of individual cars {\em{can}\/} be reduced.
The wide range of energy efficiencies of cars for sale
proves this. In a single showroom in 2006 you could buy a \ind{Honda Civic} 1.4 that
uses roughly \eccol{44\,kWh per 100\,km}, or a
\ind{Honda NSX} 3.2 that uses \eccol{116\,kWh per 100\,km} (\figref{fig.emissions}).
% 109 g/km vs 291 g/km
% 1\,kWh\ $\leftrightarrow$ 250\,g of \COO\ (oil, petrol)
%
The fact that people merrily {\em{buy}\/}
from this wide range is also proof that we need extra incentives
\marginfig{
\begin{center}
\vspace{-33mm}\par
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=25mm\epsfbox{../../images/ElectricCarOnly3S.jpg.eps}}}%
{\mbox{\epsfxsize=25mm\epsfbox{../../images/ElectricCarOnly3.eps}}} \\
\end{tabular}
\end{center}
\caption[a]{Special parking privileges for electric cars in Ann Arbor, Michigan.
}\label{figPark}
}%
and legislation to encourage the blithe consumer to {\em{choose}\/}
more energy-efficient cars.
There are various ways to help consumers prefer the Honda Civic over the
Honda NSX 3.2 gas-guzzler: raising the price of fuel;
cranking up the \ind{showroom tax} (the tax on new cars)\index{tax}
in proportion to the predicted lifetime consumption of
the vehicle; cranking up the road-tax\index{road tax} on gas guzzlers; \ind{parking}
privileges for economical cars (\figref{figPark}); or \ind{fuel rationing}.\index{rationing}
All such measures are unpopular with at least some voters. Perhaps
a better legislative tactic would be to {\em{enforce}\/} reasonable
energy-efficiency, rather than continuing to allow unconstrained choice;
for example, we could simply {\em{ban}}, from a certain
date, the sale of {\em{any}\/} car whose energy consumption is more than
80\,kWh per 100\,km; and then, over time, reduce this ceiling to
60\,kWh per 100\,km, then 40\,kWh per 100\,km, and beyond.
Alternatively, to give the consumer more choice,
regulations could force car manufacturers
to reduce the {\em{average}\/} energy consumption of all the cars they sell.
Additional \index{regulation!vehicles}\index{legislation!vehicles}legislation limiting\index{vehicle!weight}\index{vehicle!frontal area}
the weight and frontal area of vehicles
would simultaneously reduce \ind{fuel consumption} and improve
\ind{safety}\index{road safety} for other road-users (\figref{fig.monster}).
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=53mm\epsfbox{../../images/CarsSilver2.jpg.S.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/CarsSilver2.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
% Four-wheel-drive monsters
Monstercars
% like the one on the right
% not only use more fuel -- they are also
are just tall enough
to completely obscure the view and the visibility of pedestrians.
% and to obscure pedestrians from the view of other drivers.
% (Need to cut down on these figures.)
%% I think that three figure captions about how much you hate
%% people-carriers (in addition to the one in chapter 2) is a bit excessive. I
%% might agree, but I found it distracting.
}\label{fig.monster}
}%
People today choose their cars to make \ind{fashion} statements.
With strong efficiency legislation, there could
still be a wide choice of fashions; they'd all just happen
to be energy-efficient. You could choose any colour,
as long as it was green.\index{any colour, as long as it is green}
While we wait for the voters and politicians to agree to
legislate for efficient cars, what other options are available?
% \marginfig{
\begin{figure}[htbp]
\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/DutchRoundabout4S.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/DutchRoundabout4.jpg.eps}}}\,
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/DutchRoundabout2S.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/DutchRoundabout2.jpg.eps}}}\\
\end{tabular}
\end{center}
}{
\caption[a]{
A \ind{roundabout} in Enschede, \ind{Netherlands}.
}
\label{fig.rEns}
}%
\end{figure}%
\subsection{Bikes}
My favourite suggestion is the provision of excellent
cycle facilities, along with appropriate\index{bicycle}
legislation (lower speed-limits, and collision regulations
that favour cyclists, for example).\nlabel{pCycleprovision}
\Figref{fig.rEns} shows a roundabout in Enschede, Netherlands.
There are two circles: the one for cars lies inside the
one for bikes, with a comfortable car's length separating the
two.
% The bikes have their own circle, with the cars' circle inside.
% The two circles are separated by one car's length.
The priority rules are the same as those of a British roundabout,
except that cars exiting the central circle must give way to
circulating cyclists (just as British cars
give way to pedestrians on zebra crossings).
Where excellent cycling facilities are provided, people will
use them, as evidenced by the infinite number of cycles sitting
outside the Enschede
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=33mm\epsfbox{../../images/InfiniteBikes6.jpg.eps}}}\\
\end{tabular}
\end{center}
\caption[a]{
A few Dutch bikes.
% n uncountable number of
% at a Dutch railway station.
%% originals of Enschede in /home/mackay/images/070526
}\label{figBikesInf}
}%
railway station (\figref{figBikesInf}).
% Cycling benefits the non-cycling road-users because it
% reduces congestion. Every bike is one less car.
Somehow, British cycle provision (\figref{figBikesWelcome})
doesn't live up to the Dutch standard.\index{cycle lanes}
%\marginfig{
\begin{figure}[htbp]
\figuremarginb{
\begin{center}
\begin{tabular}{@{}cc@{}}
{\mbox{\epsfysize=53mm\epsfbox{../../images/WelcomeCyc4.jpg.eps}}} &
{\mbox{\epsfysize=53mm\epsfbox{../../images/TamworthRoadCroydon.eps}}}\\
\end{tabular}
\end{center}
}{
\caption[a]{
Meanwhile, back in \ind{Britain}\ldots\
\par
Photo on right by Mike Armstrong.
}\label{figBikesWelcome}
}%
\end{figure}
\pagebreak[4]
% \subsubsection{Bicycle hire}
In the French city of \ind{Lyon},\index{France} a privately-run public bicycle network,
V\'elo'v, was introduced in 2005 and has proved popular.
Lyon's population of 470\,000
% 1.6\,million
% 34*5 = 175
inhabitants is served by
2000 bikes distributed around 175 cycle-stations in an area of
50\,km$^2$ (\figref{fig.lyon}). In the city centre, you're usually within 400 metres
of a cycle-station.
Users join the scheme
by paying a subscription fee of \euro10 per year and may then
%% and a deposit of \euro150;
hire bicycles free for all trips lasting less than 30 minutes.
For
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/PUBLICDOMAIN/Lyon_velovSmall.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/PUBLICDOMAIN/Lyon_velov.jpg.eps}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{ A V\'elo'v station in Lyon.}
%% Not copyrighted
% Photo kindly contributed to {\tt{wikipedia}}.}
\label{fig.lyon}
}% \end{figure}
longer hire periods, users pay up to \euro1 per hour.
Short-term visitors to Lyon can buy one-week subscriptions
for \euro1.
%% source:
%% www.velov.grandlyon.com
%% wikipedia
\subsection{Other legislative opportunities}
Speed limits are a simple knob that could be twiddled.\index{legislation!speed limits}\index{speed limits}
As a rule, cars that travel slower use less energy (see
\chref{ch.cars2}).
% for detailed discussion.)
With practice, drivers can learn to drive more economically:
using the accelerator and brake less and always driving in the highest
possible gear can give a 20\% reduction in fuel consumption.
Another way to reduce fuel consumption is to reduce congestion.
Stopping and starting, speeding up and slowing down, is a much less
efficient way to get around than driving smoothly. Idling in
stationary traffic\index{traffic congestion}\index{congestion} is an
especially poor deliverer of miles per gallon!
Congestion occurs when there are too many vehicles on the roads.
So one simple way to reduce congestion is to group travellers
into fewer vehicles.
A striking way to think about a switch from cars to coaches
is to calculate the road area required by the two modes.
Take a trunk road on the verge of congestion,
where the desired speed is 60\,mph. The safe distance from one
car to the next at 60\,mph is 77\,m. If we assume there's one
car every 80\,m and that each car contains 1.6 people,
then vacuuming up 40 people into a single coach frees up
{\em two kilometres\/} of road!
Congestion can be reduced by providing good alternatives
(\ind{cycle lanes}, \ind{public transport}), and by charging road users
extra if they contribute to congestion. In this chapter's
notes I describe a fair and simple method for handling
congestion-charging.\nlabel{pConCharg}
\marginfig{
\begin{center}
\begin{tabular}{c}
{\epsfxsize=50mm\epsfbox{../../images/congestion.eps}} \\
%\lowres{\epsfxsize=50mm\epsfbox{../../images/CongestionCS.jpg.eps}}%
%{\epsfxsize=50mm\epsfbox{../../images/CongestionC.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{With congestion like this, it's faster to walk.
}\label{camconge}
}
\section{Enhancing cars}
Assuming that the developed world's love-affair with the
car is not about to be broken off, what are the technologies
that can deliver significant energy savings?\index{energy saving!transport}
Savings of 10\% or 20\% are easy -- we've already discussed
some ways to achieve them, such as making cars smaller and lighter.
Another option is to switch from petrol to diesel. Diesel engines
are more expensive to make, but they tend to be more fuel-efficient.
But are there technologies that can radically
increase the efficiency of the
energy-conversion chain? (Recall that in a standard petrol car,
75\% of the energy is turned into heat and blown out of the exhaust and radiator!)
And what about the goal of getting off fossil fuels?
In this section, we'll discuss five technologies:
regenerative braking; hybrid cars; electric cars;
hydrogen-powered cars; and
compressed-air cars.
% My impression is that only two of these technologies are
% truly impressive, in terms of energy efficiency.
\subsection{Regenerative braking}
There are four ways to
capture energy as a vehicle slows down.%
\index{regenerative braking}\index{braking, regenerative}
\begin{enumerate}
\item
An electric generator coupled to the wheels
can charge up an electric battery or supercapacitor.
%\marginfig{
\begin{figure}
\figuremargin{
\begin{center}
\begin{tabular}[t]{@{}r@{}}
{\mbox{\epsfysize=25mm\epsfbox{../../images/BMW2f.eps}}}
\,\,{\mbox{\epsfysize=27mm\epsfbox{figs/BMW3.eps}}} \\
{\mbox{\epsfysize=34.5mm\epsfbox{../../images/accumulator.eps}}}
\,{\mbox{\epsfysize=34.5mm\epsfbox{../../images/twomotors.eps}}} \\
\end{tabular}
\end{center}
}{
% COLON
\caption[a]{A
BMW 530i modified by \ind{Artemis Intelligent Power}
to use digital hydraulics.
Lower left: A 6-litre accumulator (the red canister), capable of
storing about 0.05\,kWh
% 180\,kJ
of energy in compressed nitrogen.
Lower right: Two 200\,kW hydraulic motors, one for each rear wheel,
which both accelerate and decelerate the car.
The car is still powered by its standard 190\,kW petrol
engine, but thanks to the digital hydraulic transmission
and regenerative braking,
it uses 30\% less fuel.
% Upper photo from \myurl{www.artemisip.com}.
% Roughly 1/3 of the saving comes from regeneration
% 1/3 from keeping engine at sweet spot
% 1/3 from the engine switching off instead of idling.
}\label{fig.BMW}
}
\end{figure}
\item
Hydraulic motors driven by the wheels can make compressed air, stored in a
small canister.
\item
Energy can be stored in
% Mechanical coupling, through gears, to
a flywheel.
\item
Braking energy can be stored as gravitational energy
by driving the vehicle up a ramp
whenever you want to slow down. This gravitational energy storage
option is rather inflexible, since there must be a ramp in the
right place. It's an option that's most useful for trains, and it
is illustrated by the London Underground's Victoria line, which has
hump-back stations. Each station is at the top of a hill in the track.
Arriving trains are automatically slowed down by the hill, and departing trains are
accelerated as they go down the far side of the hill.
The hump-back-station design provides an energy saving of 5\% and
makes the trains run 9\% faster.
% a reduction in inter-station run time of 9\%.
%% source : Ridley and Catling (1982)
\end{enumerate}
% Regenerative braking has been introduced
%% http://www.trainweb.org/tubeprune/Rolling%20Stock.htm
% on some London Underground lines since 1992.
Electric regenerative braking (using a battery to
store the energy) salvages roughly 50\% of the car's energy
in a braking event, leading to perhaps a 20\% reduction in the
energy cost of city driving.
Regenerative systems using flywheels and hydraulics seem
to work a little better than battery-based systems, salvaging
at least 70\% of the braking energy.\nlabel{pHydrauFly}
\Figref{fig.BMW} describes a hybrid car with a petrol engine
powering digitally-controlled hydraulics.\index{hydraulics, digital}
On a standard driving\index{digital hydraulics}
cycle, this car uses 30\% less fuel than the original petrol car.
In urban driving, its energy consumption
is halved, from \eccol{131\,kWh per 100\,km} to
% 20.3 mpg to 42.9 mpg
\eccol{62\,kWh per 100\,km} (20\,mpg to 43\,mpg).
(Credit for this performance improvement must be shared between
regenerative braking and the use of hybrid technology.)
Hydraulics and flywheels are both promising ways to handle regenerative
braking because small systems can handle large powers.
A flywheel system
weighing just 24\,kg (\figref{fig.flybrid}),%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\hspace*{10mm}{\mbox{\epsfxsize=43mm%
\lowres{\epsfbox{../../images/Fly2xcS.eps}}%
{\epsfbox{../../images/Fly2xcL.eps}}%
}}
{\makebox[0in][r]{\raisebox{-6mm}{\epsfxsize=23mm\epsfbox{../../images/JHflywheel.eps}%
\hspace*{30mm}}}}\\
\end{tabular}
\end{center}
\caption[a]{
A flywheel regenerative-braking system.
Photos courtesy of Flybrid Systems.
}\label{fig.flybrid}
}
designed for energy storage
in a racing car, can store 400\,kJ (0.1\,kWh) of
% 4.6 Wh/kg
energy -- enough energy to accelerate
an ordinary car up to 60\,miles per hour (97\,km/h);
% 26.8 m/s
% 26.8**2 *0.5*1000 / 3.6e6
and it can accept or deliver 60\,kW of power.
Electric batteries capable of delivering that much power
would weigh about 200\,kg.\nlabel{LiIonP}
% 1800 W per kg from wikipedia and 300-1500 W/kg 625 W/kg 1350 W/kg 300 W/kg
% I go for 300 W/kg
So, unless you're already carrying that much battery
on board, an electrical regenerative-braking system should
probably use capacitors to store braking energy. Super-capacitors
have similar energy-storage and power-delivery parameters to the flywheel's.
\subsection{Hybrid cars}
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Prius4S.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Prius4.jpg.eps}}}\\
\end{tabular}
\end{center}
\caption[a]{Toyota Prius --
according to Jeremy Clarkson,\index{Clarkson, Jeremy}
``a very expensive,
very complex, not terribly green,
slow, cheaply made, and pointless
way of moving around.''
}\label{fig.Prius}
}%% http://driving.timesonline.co.uk/tol/life_and_style/driving/used_car_reviews/article3552994.ece BMW diesel 50.3 mpg 10.84 gal DIESEL
%% Prius - 48.1mpg on same trip 11.34 gal PETROL
%% in energy terms that means 115.99 : 110.00 kWh * gal/l
%% So the BMW did use slightly more. And it was cheaper.
%% ## the range incidentally was 500 miles for a petrol car
Hybrid cars\index{car!hybrid}\index{hybrid cars}
such as the Toyota \ind{Prius} (\figref{fig.Prius}) have more-efficient
engines and electric regenerative
braking, but to be honest, today's hybrid vehicles
don't really stand out from the crowd
(\figref{fig.emissions}).\nlabel{pPrius}
The horizontal bars
in \figref{fig.emissions}
highlight a few cars including two hybrids.
Whereas the average new car in the UK emits 168\,g,\nlabel{car168}
the hybrid Prius emits about 100\,g of \COO\ per km, as do
several other non-hybrid vehicles -- the VW Polo blue motion emits 99\,g/km,
and there's a Smart car that emits 88\,g/km.\index{hybrid cars!misleading advertising}
The \ind{Lexus} RX\,400h is\index{Lexus!misleading advertising}
the second hybrid,\index{hybrid cars!compared}
advertised with the slogan ``LOW POLLUTION\@. ZERO GUILT.'' But its
\COO\ emissions are 192\,g/km -- worse than the average UK car!
The \ind{advertising standards authority} ruled that this
advertisement breached the advertising codes\index{misleading advertising}
on Truthfulness, Comparisons and Environmental claims.
``We considered that \ldots readers were likely to understand
that the car caused little or no harm to the environment,
which was not the case, and had low emissions in comparison
with all cars, which was also not the case.''
In practice, hybrid technologies seem to give fuel savings of
20 or 30\%.\nlabel{hybrid20}
So neither these petrol/electric hybrids, nor the
petrol/hydraulic hybrid featured in \figref{fig.BMW}
seems to me to have really cracked the transport challenge. A 30\% reduction
in fossil-fuel consumption is impressive, but it's not enough by
this book's standards. Our opening assumption was that we want to
get off fossil fuels, or at least to reduce fossil fuel use by 90\%.
Can this goal be achieved without reverting to bicycles?
\begin{figure}[htbp]
\figuredangle{
\begin{center}
\begin{tabular}{@{}l@{}}
\lowres{\mbox{\epsfysize=36.5mm\epsfbox{../../images/electriccarS.jpg.eps}}}%
{\mbox{\epsfysize=36.5mm\epsfbox{../../images/electriccar.eps}}}
\,
\lowres{\mbox{\epsfysize=36.5mm\epsfbox{../../images/c5.50.eps}}}%
{\mbox{\epsfysize=36.5mm\epsfbox{../../images/c5.eps}}}
\,
\lowres{\mbox{\epsfysize=36.5mm\epsfbox{../../images/ElecCitroen1c.jpg.S.eps}}}%
{\mbox{\epsfysize=36.5mm\epsfbox{../../images/ElecCitroen1c.jpg.eps}}}
\,
\lowres{\mbox{\epsfysize=36.5mm\epsfbox{../../images/ElettricaS.jpg.eps}}}%
{\mbox{\epsfysize=36.5mm\epsfbox{../../images/Elettrica.eps}}} \\
\end{tabular}
\end{center}
}{
\caption[a]{%Are electric vehicles a good idea?
Electric vehicles.
From left to right: the \ind{G-Wiz};
the rotting corpse of a Sinclair C5;\index{Sinclair C5}\index{C5}
a \ind{Citro\"en Berlingo};\index{Berlingo}
%% http://www.carpages.co.uk/citroen/citroen_alternative_fuel_new_look_berlingos_28_01_03.asp
and an \ind{Elettrica}.
}\label{Berlingo}
}%
\end{figure}%
\subsection{Electric vehicles}
The \ind{REVA}\index{car!electric}\index{vehicle!electric} electric
car was launched in June 2001 in Bangalore
and is exported to the UK as the G-Wiz.%
\amarginfig{t}{\footnotesize
\begin{center}
\mbox{%
\epsfxsize=53mm\epsfbox{../data/car/GWiz.eps}%
\makebox[0in][r]{\raisebox{10mm}{%
\lowres{\mbox{\epsfxsize=20mm\epsfbox{../../images/electriccarS.jpg.eps}}}%
{\mbox{\epsfxsize=20mm\epsfbox{../../images/electriccar.eps}}}%
}\hspace*{2mm}%
}%
}%
\end{center}
\caption[a]{% Measurements of e
Electricity required to recharge
a G-Wiz versus distance driven. Measurements were made at the
socket.\index{data!G-Wiz}
% with a Maplin meter.
% Each data point is labeled by the
% date (day/month).
}
\label{fig.GWiz}
}
The \ind{G-Wiz}'s electric motor has a peak power of 13\,kW, and
can produce a sustained power of 4.8\,kW\@.
% Its torque is 70\,Nm.
The motor provides regenerative braking.
It is powered by eight 6-volt lead acid batteries, which when
%% 200Ah range 48 miles (or 40 on mixed roads)
%% 63 g/km assuming 470g/kWh in the grid.
fully charged give a range of ``up to 77\,km.'' A full charge consumes 9.7\,kWh
%% http://www.goingreen.co.uk/store/content/gwiz_techspec/
of electricity. These figures imply a transport cost of
13\,kWh per 100\,km.\index{transport!efficiency!electric car}\label{pWizClaim}
% 800 charges until battery starts to die?
Manufacturers
always quote the best possible performance
of their products. What happens in real life?
% [Don't forget the charging efficiency, which is about 85\%.]
%% does this agree with the US figure for a hybrid electric vehicle of 3.4 miles per kWh
%% ``a PHEV would need about 9-10 kWh to drive the 25-30 miles provided by a gallon''
%% www.goinggreen.co.uk and www.revaindia.com
The real-life performance of a G-Wiz in London\index{G-Wiz!data}
is shown in \figref{fig.GWiz}.
Over the course of 19 recharges, the average transport cost of this G-Wiz
is \eccol{21\,kWh per 100\,km} -- about four times better than
an average fossil fuel car.
The best result was 16\,kWh per 100\,km, and the worst
was 33\,kWh per 100\,km.\index{transport!efficiency!electric car}\index{data!G-Wiz}\index{data!electric car}\index{electric car!data}
If you are interested in carbon emissions, {21\,kWh per 100\,km}
is equivalent to 105\,g\,\COO\ per km, assuming that
electricity has a footprint of 500\,g\,\COO\ per kWh.
Now, the G-Wiz sits at one end of the performance spectrum.
What if we demand more -- more acceleration, more speed, and more range?
At the other end of the spectrum is the
% see tesla.tex
%\item[Tesla Roadster 2008]
\ind{Tesla Roadster}.
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm%
\epsfbox{../../images/TeslaRb.eps}%
}}
\\[-0.3in]
\end{tabular}
\end{center}
\caption[a]{\ind{Tesla Roadster}:
\eccol{15\,kWh per 100\,km}.
\myurlb{www.teslamotors.com}{http://www.teslamotors.com/}.
}\label{tesla}
}%
The Tesla Roadster 2008 has a range
of 220 miles (354\,km);
its lithium-ion battery pack stores 53\,kWh and weighs 450\,kg
(120\,Wh/kg). The vehicle weighs 1220\,kg and its motor's maximum power is
185\,kW\@.
What is the energy-consumption of this muscle car?
Remarkably, it's better than the G-Wiz:
% thus the 450kg of battery is capable of delivering at least 0.41 kW per kg
\eccol{15\,kWh per 100\,km}.
%\item[Tesla Model S]
% a high performance electric sedan, with
% lithium-ion batteries.
% Range: 225 miles.
Evidence that a range of 354\,km should be enough for most people
most of the time comes from the fact that
only 8.3\%
of commuters travel\index{data!commuting}\index{commuting, data}
more than 30\,km to their workplace.\nlabel{pEddRang}
I've looked up the performance figures for lots of electric vehicles\nlabel{lotsE}
-- they're listed in this chapter's end-notes --
and they seem to be consistent with this summary:
electric vehicles can
% replace fossil-cars, and can
deliver
transport at an energy cost of
roughly \eccol{15\,kWh per 100\,km}.
That's five times better than our baseline fossil-car, and significantly better
than any hybrid cars. Hurray!
\begin{figure}[htbp]
\figuremargin{
\begin{center}
\mbox{\epsfbox{metapost/stacks.449}} \\
\end{center}
}{
\caption[a]{Energy requirements \par
of different forms of \par
passenger transport.
The vertical coordinate shows the
energy consumption in kWh per 100 passenger-km.
The horizontal coordinate indicates the speed of the transport.
The ``Car (1)'' is an average UK car doing 33 miles per gallon
with a single occupant.
The ``Bus'' is the average performance of all London buses.
The ``Underground system'' shows the performance of the whole
London Underground system.
% , including the energy cost of its lighting,
% escalators, and depots.
The catamaran is a diesel-powered vessel.
% planing boat.
\par
% In response to popular demand,
I've indicated
on the left-hand side
% how these energy-efficiencies
% translate into fuel-efficiencies expressed
equivalent fuel efficiencies
in passenger-miles per imperial \newlineone
gallon (p-mpg).
% When comparing electric with chemical-powered
% vehicles, I've expressed both energy requirements
% in kWh with a one-for-one exchange rate.
%% 2184 mpg at 15 mph which is 6.7 m/s or 24.14 km/h
%% Team crocodile eco-car 773.149199 km per litre
%% 10 kWh per 773 pkm , which is 1.3 kWh per 100 pkm
\par
Hollow point-styles show best-practice performance,
assuming all seats of a vehicle are in use.
Filled point-styles indicate actual performance
of a vehicle in \newlineone
typical use.
\par
See also \figref{freight458} (energy requirements of freight transport).%
\index{Cessna}\index{QE2}\index{Range Rover}\index{hydrogen car}\index{train}\index{catamaran}%
\index{helicopter}\index{747}\index{electric car}\index{bus}\index{eco-boat}\index{jet-ski}%
\index{bicycle}\index{ocean liner}\index{turboprop}\index{Learjet}
}\label{passenger}
}
\end{figure}%
To achieve economical transport, we
don't have to huddle together in public transport -- we can still
hurtle around, enjoying all the pleasures and freedoms of solo travel,
thanks to electric vehicles.
% ``an electric car with a usable range''
% http://www.carmagazine.co.uk/Drives/Search-Results/First-drives/Tesla-Roadster-CAR-review/?content-block=2
This moment of celebration
feels like a good time to unveil this chapter's big summary diagram,
figure \ref{passenger}, which shows the energy requirements of
all the forms of passenger-transport we have discussed and a couple that are still
to come.
OK, the race is over, and I've announced two winners -- public transport,
and electric vehicles.
But are there any other options crossing the finishing line?
We have yet to hear about the compressed-air-powered car
and the hydrogen car.
If either of these turns out to be better than electric
car, it won't affect the long-term picture very much: whichever of these
three technologies we went for, the vehicles would be charged up
using energy generated from a ``green'' source.
\subsection{Compressed-air cars}
Air-powered vehicles are
not a new idea.
% 250
Hundreds of trams powered by compressed air and hot water
plied the streets of Nantes and Paris from 1879 to 1911.
% pressure 60 atm (840 psi)
% in the UK test, used 5 times as much coal as a coal-powered steam locomotive
% http://www.dself.dsl.pipex.com/MUSEUM/TRANSPORT/comprair/comprair.htm
% Jung PZ 20 Pressluft Grubenlok
% pressure 2900 psi, Power 20 hp, weight 5.6 tonnes
% http://www.tramways.freeserve.co.uk/Tramframe.htm?http://mysite.wanadoo-members.co.uk/tramways/Articles/Compair2.htm
% nantes system used 15.64 lb. of coal per car mile.
% \Figref{figCompress} shows an American mining locomotive from 1923
% and a German pneumatic locomotive from 1955. % Jung
\Figref{figCompress} shows
a German pneumatic locomotive from 1958.
% JungPZ20.eps.
% Until 1987 the German company Arnold Jung Lokomotivenfabrik GmbH produced locomotives functioning on compressed air to be used in mines.
% source http://www.theaircar.com/air-cars/compressed-air-history.html
I think that in terms of energy efficiency
the compressed-air technique for storing energy
isn't as good as electric batteries.
The problem is that compressing the air
generates {\em{heat}\/} that's unlikely to be
used efficiently; and expanding the
air generates {\em{cold}}, another by-product that is unlikely to be
used efficiently.
But compressed air may be a superior
technology to electric batteries
in other ways. For example, air can be compressed
thousands of times and doesn't wear out!
It's interesting to note, however, that the first product
sold by the \ind{Aircar} company
% (also known as MDI)
is actually
an {\em{electric}\/} scooter.
% http://www.theaircar.com/acf/vehicle-sale/electrical-motorbikes.html
% which has a 20Ah (48V) battery , range 75km - all three of them
% and all have a 2kW engine.
[\myurlb{www.theaircar.com/acf}{http://www.theaircar.com/acf/}]
% Assume 300 bar pressure
% and compare the energy per kilogram
% and per unit volume
% with that of batteries.
% Include in the storage diagram.
% http://en.wikipedia.org/wiki/Pressure_vessel
% required mass of pressure vessel is
% M = (3/2) PV rho / sigma
% maximum stress is sigma
% Note no dependence of ratio M/energy on size.
\marginfig{
\begin{center}
\begin{tabular}{@{}cc@{}}
\multicolumn{2}{@{}c@{}}{%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Canantes1.eps}}}%
}
\\
%\lowres{\mbox{\epsfxsize=23mm\epsfbox{../../images/compressedairlocoS.eps}}}%
%{\mbox{\epsfxsize=23mm\epsfbox{../../images/compressedairlocoM.eps}}}%
%&
{\mbox{\epsfxsize=53mm\epsfbox{../../images/frnkfrt1.eps}}}%
%{\mbox{\epsfxsize=28mm\epsfbox{../../images/JungPZ20.eps}}}%
\\
\end{tabular}
\end{center}
%
\caption[a]{Top:
A compressed-air tram taking on air and steam in Nantes.
% The tram carried both compressed air and super-heated water
% to warm the air as it expanded.
Powering the trams of Nantes used 4.4\,kg of coal (36\,kWh)
per vehicle-km, or \eccol{115\,kWh per 100\,\pkm}, if
the trams were full.
% 210\,kWh per seat-km.
\tinyurl{5qhvcb}{http://www.tramwayinfo.com/Tramframe.htm?http://www.tramwayinfo.com/tramways/Articles/Compair2.htm}
% 31 passengers , 17 seated
% 15.64 lb. of coal per car mile
% 29.3 GJ per ton
% 29.3 MJ per kg
% 8.1 kWh per kg
% 35.6 kWh per km; 210 kWh per 100 p-km
% 115 kWh per 100 pkm
% Left:
% A compressed-air locomotive
% at Arizona Railroad Museum.
% Its tank's pressure was 1000\,psi (69\,bar).
% built by the Porter Locomotive Company in 1923.
% weight 10,000 lb;
% 23 inch wheels, can exert a force of 18,600 lb
% boiler pressure was 1000 psi
% Photo by Jot Powers.
Bottom:
% Right:
A compressed-air locomotive; weight 9.2\,t, pressure 175\,bar,
power 26\,kW;
% , top speed 18\,km/h;
photo courtesy of
R\"udiger Fach,
% photo of autumn colours made in 1996
% J\"urgen Herkelmann,
Rolf-Dieter Reichert,
and Frankfurter Feldbahnmuseum.
% J\"urgen Herkelmann, date of June 2005.
% Right: Jung PZ 20.
% Tank pressure: 2900 psi (200\,bar); power: 15\,kW; weight: 5.6\,t.
% Power 20 HP
% Weight 5.6 tonnes
}\label{figCompress}
}%
There's talk of Tata Motors in India manufacturing air-cars,
but it's hard to be sure whether the compressed-air vehicle is going
to see a revival, because no-one has published the specifications
of any modern prototypes. Here's the fundamental limitation:
the energy-density of compressed-air energy-stores is
only about 11--28\,Wh per kg,\nlabel{compAir} which is similar to lead-acid batteries,
and roughly five times smaller than lithium-ion
batteries.
(See \figref{fig.batteriesFuels}, \pref{fig.batteriesFuels},
for details of other storage technologies.)
So the range of a compressed-air car will only ever be as
good as the range of the earliest electric cars.
% This is not as energy-dense as an electric battery, but c
Compressed-air
storage systems do have three advantages over batteries: longer life,
cheaper construction, and fewer nasty chemicals.
% TATA involved
% http://www.autoindustry.co.uk/news/21-08-07_1
% this press release mentions 30-35 g COO per km
% http://news.bbc.co.uk/1/hi/sci/tech/7243247.stm
% 5-seater car, 350kg.
% ``Mr Negre has been promising for more than a decade to be on the verge of a breakthrough.''
% 4 hour charging at home must mean 12kWh
% for the range which is 125 miles according to press releases.
% Two companies
% MDI motor development international Guy Negre
% claim 4500 km range in the future??
% 4 cylinder engine, made aluminium.
% 300 bar pressure about 1ft diameter, carbon fibre
% chassis Al. Refill in 3 minutes. Onboard compressor
% refill in 4 hours at home.
%%
% Melbourne inventor 13kg engine. Rotary air motor.
% http://www.climatechangecorp.com/content.asp?ContentID=5154
% TATA and MDI - delays...
% In fact their main project uses combustion fuel:
% ``It is important to realise that the main version of the MDI engine is designed to run in multi-fuel mode.''
% http://anz.theoildrum.com/node/3526
% IT-MDI Spokesperson claims 150km range at driving speed of 50 km/h
% Talks a lot about multi-fuel!
% http://www.mdi.lu/eng/affiche_eng.php?page=accueil
% this page
% http://www.mdi.lu/eng/affiche_eng.php?page=minicats
% says 5.5 hours to reill at home.
\subsection{Hydrogen cars -- blimp your ride}
I think hydrogen is a hyped-up bandwagon.
I'll be delighted to be proved wrong, but I don't see how hydrogen
is going to help us with our energy problems.
Hydrogen is not a miraculous {\em{source}\/} of energy;
it's just an energy {\em{carrier}}, like a rechargeable battery.
% Hydrogen is not an energy source, it's just an energy {\em{carrier}},
And it is
a rather inefficient energy carrier, with a whole bunch of practical defects.
The
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm%
\epsfbox{../../images/Hummer-H2H.eps}%
}}
\end{tabular}
\end{center}
\caption[a]{\index{Hummer}\index{GM}\index{General Motors}The Hummer H2H:
embracing the green revolution, the American way.
Photo courtesy of General Motors.
}\label{H2H}
}%
``hydrogen economy'' received support from
\index{Nature magazine}{{\tem{Nature}\/} magazine} in a column praising California Governor
Arnold Schwarzenegger
for filling up a \ind{hydrogen}-powered\index{Schwarzenegger, Arnold}
\ind{Hummer} (\figref{H2H}).\label{pageArnold}
{Nature}'s article
% uncritically praised
lauded Arnold's
vision of hydrogen-powered cars replacing
% ``the polluting models on the road''
``polluting models''
with the quote ``the governor
is a real-life climate action hero.''
% today
But the critical question that needs to be asked when such hydrogen heroism is
on display is ``where is the {\em{energy}\/} to come from to {\em{make}\/}
the hydrogen?''
% Hydrogen is not a miraculous {\em{source}\/} of energy;
% it's just an energy {\em{carrier}}, like a rechargeable battery.
% The two methods used to produce hydrogen today are steam reformation of natural
% gas and electrolysis
Moreover, converting energy to and from hydrogen can only be
done inefficiently -- at least, with today's technology.
Here are some numbers.
\begin{itemize}
\item In the \ind{CUTE} (Clean Urban Transport for Europe) project, which was intended
to demonstrate the feasibility
and reliability of \index{fuel cell!bus}{fuel-cell bus}es and \ind{hydrogen} technology,
fuelling the hydrogen buses required
between 80\% and 200\% {\em more\/} energy than the baseline diesel bus.\nlabel{pageCUTE}
\item
Fuelling the {\sl Hydrogen 7},
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/bmw7Hydrogen.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{{BMW Hydrogen 7}.\index{hydrogen car}
Energy consumption: \eccol{254\,kWh per 100\,km}.
Photo from BMW.
}\label{bmw7}
}
the
hydrogen-powered car made by BMW\index{BMW!Hydrogen 7}, requires
\eccol{254\,kWh per 100\,km} --
{\em 220\% more\/} energy than an average European car.\nlabel{pBMW}
\end{itemize}
If our task were ``please stop using fossil fuels
for transport,
allowing yourself the assumption that {\em{infinite}\/} quantities
of green electricity are available for free,''
then of course an energy-profligate transport solution like
hydrogen might be a contender (though hydrogen faces other problems).
But {\em green electricity is not free}.
Indeed, getting green electricity
on the scale of our current consumption
is going to be very challenging. The fossil fuel challenge is an energy challenge.
The climate-change problem is an energy problem.
We need to focus on solutions that use less energy,
not ``solutions'' that use more!
{\em{I know of no form of land transport whose energy consumption is
worse than this hydrogen car}}.
(The only transport methods I know that are worse
are \ind{jet-ski}s --
using about \eccol{500 kWh per 100\,km} --
% at 30 mph
and the {\em{Earthrace}\/} biodiesel-powered \ind{speed-boat},
absurdly called an \ind{eco-boat},
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm%
\lowres{%
\epsfbox{../../images/Earthrace-2S.eps}%
}{%
\epsfbox{../../images/Earthrace-2M.eps}%
}%
}}
\end{tabular}
\end{center}
\caption[a]{%
The Earthrace ``eco-boat.''
Photo by David Castor.
}\label{fig.earthrace}
}%
which uses \eccol{800 kWh per 100\,\pkm}.)
% at 25 knots 46.3 km/h
Hydrogen advocates may say ``the BMW Hydrogen 7 is just an
early prototype, and it's a luxury car with lots of
muscle -- the technology is going to get more efficient.''
Well, I hope so, because it has a lot of catching up to do.
The Tesla Roadster (\figref{tesla}) is an early prototype too,
and it's also a luxury car with lots of muscle. And it's
more than ten times more energy-efficient than the Hydrogen 7!
Feel free to put your money on the hydrogen horse
if you want, and if it wins in the end, fine.
But it seems daft to back the horse that's so far behind
in the race. Just look at \figref{passenger} -- if I hadn't
squished the top of the vertical axis, the hydrogen car would not
have fitted on the page!
Yes, the \index{Honda!FCX Clarity}\index{Honda!fuel-cell car}{Honda}
fuel-cell car, the FCX Clarity,\nlabel{FCXHonda}
does better -- it rolls in at \eccol{69\,kWh per 100\,km} -- but my prediction is
that after all the ``zero-emissions'' trumpeting is over, we'll find
that hydrogen cars use just as much energy as the average fossil car
of today.%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm%
\epsfbox{../../images/JLC_FCXClarity.eps}%
}}
\end{tabular}
\end{center}
\caption[a]{%
The Honda FCX Clarity hydrogen-powered fuel-cell sedan, with
a Jamie Lee Curtis\index{Curtis, Jamie Lee} for scale.
Photo courtesy of
\myurlb{automobiles.honda.com}{http://automobiles.honda.com/}.
}\label{fig.FCXHonda}
}%
%
% Honda FCX Clarity - hydrogen-powered fuel cell sedan, with
% Jamie Lee Curtis for scale
% Photo courtesy of automobiles.honda.com
% http://automobiles.honda.com/fcx-clarity/specifications.aspx
% fuel cell output is 100kW and weighs 148lb elec motor is 100kW range 280mi
%\subsubsection{Other problems with hydrogen}
Here are some other problems with hydrogen.
Hydrogen is a less convenient energy storage medium than most liquid fuels,
because of its bulk,
whether stored as a
high pressure gas or as a liquid (which requires a temperature of
$-253$\degreesC).
Even at a pressure of 700\,bar (which requires a hefty
pressure vessel) its energy density (energy per unit volume)
is 22\% of gasoline's.
The cryogenic tank of the BMW Hydrogen 7
% \,745h
weighs 120\,kg and stores 8\,kg of
hydrogen.
% at 39\,kWh per kg that means it's actually got a net energy density of
% 2.44 kWh per kg
% 2440 Wh per kg
Furthermore, hydrogen gradually leaks out of any practical
container. If you park your hydrogen car at the railway station
with a full tank and come back a week later, you should expect to find most of
the hydrogen has gone.
\subsection{Some questions about electric vehicles}
\beforeqa
\qa{You've shown that electric cars are more energy-efficient
than fossil cars. But are they better if our objective is to
reduce \COO\ emissions, and the electricity is still generated by fossil
power-stations?\index{carbon-dioxide emissions!electric car}
}{
This is quite an easy calculation to do.\index{electric car!CO$_2$ emissions}
Assume the electric vehicle's energy cost is 20\,\kWhe\ per 100\,km. (I
think 15\,\kWhe\ per 100\,km is perfectly possible, but let's play sceptical
in this calculation.)
If grid electricity has a carbon footprint of 500\,g per \kWhe\
then the effective emissions of this vehicle are {\bf 100\,g\,\COO\ per km},
which is as good as the best
fossil cars (\figref{fig.emissions}).\index{electricity!supply}
So I conclude that switching to electric cars is {\em{already}\/} a good
idea, even before we green our electricity supply.\index{electricity!greening of}\index{greening electricity supply}
}
% aptera -- claim is that is does 130mpg when detached from the mains,
% running on fossil fuel alone.
% prototype: 9kW diesel engine and 18 kW DC motor. Uses ultracapacitors.
% drag coefficient 0.11 230mpg at 55 mph?
% (I think they are treating elec as free)
% now gasoline series hybrid. Electric motor 30kW, range 120 miles. battery 10kWh?
% CONSUMES 60 Wh per km (wikipedia) 450l of cargo space
% ie 6kWh per 100 km
% also has solar panels for slow charge.
% black cabs
% Smith are part of \myurl{http://www.tanfieldgroup.com/}
\qa{Electric cars, like fossil cars,\index{life-cycle analysis}
have costs of both manufacture and use.
Electric cars may cost less to use, but if the batteries don't
last very long, shouldn't you pay more attention to
the \ind{manufacturing} cost?\index{electric vehicle!battery cost}
}{
Yes, that's a good point. My transport diagram shows only the
use cost. If electric cars require new batteries every few years,
my numbers may be underestimates.\index{electric vehicle!lifetime}
The batteries in a Prius are expected to last just 10 years,
and a new set would cost \pounds3500.
Will anyone want to own a 10-year old Prius and pay that cost?
It could be predicted that most Priuses will be junked at age 10 years.
This is certainly a concern for all electric vehicles that have batteries.
I guess I'm optimistic that, as we switch to electric vehicles,
battery technology is going to improve.
}
\qa{I live in a hot place. How could I drive an electric car? I demand power-hungry
air-conditioning!}{
There's an elegant fix for this demand:\index{electric vehicle!in hot places}
fit 4\,m$^2$ of photovoltaic panels in the upward-facing surfaces of the electric car.
If the air-conditioning is needed, the sun
must surely be shining. 20\%-efficient panels will generate up to 800\,W, which is
enough to power a car's
air-conditioning.\index{air-conditioning!in vehicles}
The panels might even make a useful contribution to charging the
car when it's parked, too.
% Toyota are doing this
% http://uk.reuters.com/article/email/idUKT29871820080706
% http://ukpress.google.com/article/ALeqM5huHn0G07VL7ISkd317HzOkbyceYA
% 2-5kW of power ? come off it!
% The Japan-built 1993 Mazda 929 featured optional solar cells \u201cembedded in the glass sunroof to power fans that remove hot air from the inside the car when it is parked.\u201d
Solar-powered vehicle cooling was included in
a \ind{Mazda} in 1993; the solar cells were embedded in the
glass \ind{sunroof}.\index{solar power!in vehicles}
}
\qa{I live in a cold place. How could I drive an electric
car?\index{electric vehicle!in cold places}
I demand power-hungry heating!}{
The motor of an electric vehicle, when it's running,
will on average use something like 10\,kW, with an efficiency of
90--95\%. Some of the lost power, the other 5--10\%,
will be dissipated as heat in the motor.
Perhaps electric cars that are going to be used in cold
places can be carefully designed so that this motor-generated
heat, which might amount to 250 or 500\,W,
can be piped from the motor into the car. That much power would
provide some significant windscreen demisting or body-warming.
}
\qa{
Are lithium-ion batteries safe in an accident?
}{
Some lithium-ion batteries are unsafe when short-circuited
or overheated, but the
battery industry is now producing safer batteries
such as lithium phosphate.
% http://www.valence.com/products/ucharge_overview.html
% 1280 Wh per 15.8 kg
% 100 Ah
% Another model ``Epoch'' has 1306 Wh (68Ah) in 15.6 kg 84 Wh/kg
% or 1562 Wh in 18.6 kg 84 Wh/kg
There's a fun safety video at \myurl{www.valence.com}.
}
%% Enough lithium?}
\beforeqa
\qa{Is there enough lithium to make all the batteries for a
huge fleet of electric cars?}{
World lithium reserves are
estimated to be 9.5 million tons in ore deposits (\pref{brazilNot}).
A lithium-ion battery is 3\% lithium.\nlabel{FisherBattery}
% source
% http://www.defra.gov.uk/environment/waste/topics/batteries/pdf/erm-lcareport0610.pdf
If we assume each vehicle has a 200\,kg battery, then we need 6\,kg of
lithium per vehicle.
% 9.5e6*1e3 / 6
% ans = 1.5833e+09
So the estimated reserves in ore deposits are enough to make
the batteries for 1.6\,billion vehicles.
% There is 230 bn tons in sea water too. ``Not easy to extract''
% http://sciencelinks.jp/j-east/article/200702/000020070206A1021422.php
That's more than the number of cars in the world today
(roughly 1 billion)
-- but not
much more, so the amount of lithium may be a concern, especially
when we take into account the competing ambitions of the nuclear fusion posse
(\chref{ch.fusion})
to guzzle lithium in their reactors.
There's many thousands times more lithium in sea water, so
perhaps the oceans will provide a useful backup.
However, lithium specialist R.\ Keith Evans says\nlabel{pEvans}
``concerns regarding lithium availability for hybrid or electric vehicle batteries or other foreseeable applications are unfounded.''
% \cite{LithiumEvans}
And anyway, other lithium-free battery technologies
such as zinc-air rechargeables
are being developed
[\myurlb{www.revolttechnology.com}{http://www.revolttechnology.com/}].
% they claim 1100 Wh per litre. That's 500Wh per kg maybe?
I think the electric car is a goer!
}
%%%%%%%%%%%%%%%% PLANES %%%%%%%%%%%%%%%%%%
\section{The future of flying?}% The A380:
\amarginfig{c}{
\begin{center}
\begin{tabular}{@{}c@{}}
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/AirbusA380Crop.jpg.eps}}}\\
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/AirbusA380CC.jpg.eps}}}\\
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/AirbusA380CCCS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/AirbusA380CCC.jpg.eps}}}\\
%%% lovely cropped picture for more see _flight.tex
\end{tabular}
\end{center}
\caption[a]{
\ind{Airbus} \ind{A380}.
}
}%
%\section{Plane costs}
% The Airbus A380 costs 235--252 million \euro.
% (BBC News, 23 June 2006).
%%%newimage -zoom 200 "sustainableimages/airbus-a-380-1.jpg"
The \ind{superjumbo} A380 is said by \ind{Airbus} to be
``a highly fuel-efficient \ind{aircraft}.''
In fact,\index{myth!new planes far more efficient}
% as they say when you look closely,
it burns just 12\% less fuel per passenger
than a \ind{747}.\label{pAirbus}
% And in fact since the A380 is intended by its owners
% to reduce the price of flying, it's actually going to increase demand
% for flying. So it seems unlikely that pollution will go down.
%% Indeed, the A380 will be the first long-haul aircraft to consume less than three litres of fuel per passenger over 100 km, a rate comparable to an economical family car.
% {\durl{http://www.airbus.com/en/myairbus/airbusview/the_a380_the_future_of_flying.html}}
%%%%%%%%%%%
%
% see _flight.tex
%
% The B-2 bomber (cost per plane, \$1--2 billion). Range 11\,000\,km.
% gaurdian Wed 6/6/07 advert
Boeing has
announced similar breakthroughs: their new 747--8 Intercontinental,\index{flight!future of}
trumpeted for its planet-saving properties, is (according to
Boeing's advertisements) only 15\% more fuel-efficient than a 747--400.
%% < 3 litres per 100 passenger km - that's 26.4 kWh per 100 pa-km.
%% < 75g \COO\ per passenger km
This slender rate of progress (contrasted with cars, where
changes in technology deliver two-fold or even ten-fold
improvements in efficiency) is explained in Technical \appref{ch.flight2}.
Planes are up against a fundamental limit imposed by the laws of
physics.
% in freight ch I say 1.63 kWh per tkm
Any plane, whatever its size, {\em has to\/} expend an
energy of about 0.4\,kWh per \ton-km on keeping up and keeping moving.
Planes have already been fantastically optimized, and there is no prospect
of significant improvements in plane efficiency.
For a time, I thought that
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/rijndam-maiden-nyc.eps}}}
\\
% thank Reuben Goossens
\end{tabular}
\end{center}
\caption[a]{TSS \ind{Rijndam}.
% arriving in New York City.
}\label{rijnsdam}
}%
the way to solve the long-distance-transport
problem was to revert to the way it was done before planes:
\ind{ocean liner}s.
Then I looked at the numbers.
The sad truth is that ocean liners use more energy
per passenger-km than jumbo jets.
The QE2 uses four times as much energy per passenger-km as a jumbo. OK, it's a
luxury vessel; can we do better with slower tourist-class liners?
From 1952 to 1968, the economical way to cross the Atlantic was
in two Dutch-built liners known as ``The Economy Twins,''
the Maasdam and the Rijndam.
These travelled at 16.5 knots (30.5\,km/h), so the crossing from
Britain to New York took eight days.
Their energy consumption, if they carried a full load of
893 passengers, was {103\,kWh per 100\,\pkm}. At a typical 85\% occupancy,
the energy consumption was \eccol{121\,kWh per 100\,pkm} -- more than twice that
of the jumbo jet.\nlabel{DutchBoats}
% they managed 85% occupancy on atlantic voyages.
To be fair to the boats, they are not only providing transportation: they also
provide the passengers and crew with hot air, hot water, light, and entertainment
for several days; but the energy saved back home from being cooped
up on the boat is
% : it's only about 3\% of
dwarfed by the boat's energy consumption, which, in the case of the QE2,
is about 3000\,kWh per day per passenger.
% 1615 pax, 200MW , -> 123kW per pax, 2952 kWh/d per pax
So, sadly, I don't think boats are going to beat planes in energy
consumption.
If eventually we want a way of travelling large distances without
fossil fuels, perhaps nuclear-powered ships are an interesting option
(figures \ref{Savannah} \& \ref{Yamal}).
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/NSsavannah-1962c.eps}}}
\\
% http://en.wikipedia.org/wiki/NS_Savannah
% length 182m 9900 long tons deadweight
% One 74 MW Babcock & Wilcox nuclear reactor powering two De Laval steam turbines[2]
% Propulsion: 20,300 hp to a single propeller
\end{tabular}
\end{center}
\caption[a]{\ind{NS Savannah}\index{Savannah},
the first commercial nuclear-powered
{cargo vessel},\index{cargo vessel!nuclear-powered}
passing under the Golden Gate Bridge in 1962.\index{ship!nuclear-powered}\index{boat!nuclear-powered}
% She has one 74\,MW reactor, and her motor can deliver 15\,MW\@.
}\label{Savannah}
}%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/NuclearicebreakeryamalCS.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/NuclearicebreakeryamalC.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{The nuclear \ind{ice-breaker} \ind{Yamal}, carrying 100 tourists
to\index{ship!nuclear-powered}\index{boat!nuclear-powered}
the North Pole in 2001.
% She has two 171\,MW
% reactors, and her motors can deliver 55\,MW\@.
% http://www.coolantarctica.com/Antarctica%20fact%20file/ships/Yamal_ice_breaker.htm
% length 150m displacement 23,455tonnes
% max speed 22knots 40 km/h cruising speed 19.5 kn, 35km/h
% can break 5m ice. can break 2.3m ice at 3 knots
% http://en.wikipedia.org/wiki/Yamal_%28icebreaker%29
% It's in the Arktika class
Photo by Wofratz.
% CC-by-sa-2.5
% http://en.wikipedia.org/wiki/Image:Nuclearicebreakeryamal.jpg
}\label{Yamal}
}
\section{What about freight?}
International \ind{shipping}\index{freight} is a surprisingly efficient user of
fossil fuels; so getting road transport off fossil fuels is a higher priority
than getting ships off fossil fuels. But fossil fuels are a finite resource,
and eventually ships must be powered by something else.
Biofuels {\em{may}\/} work out.
Another option will be nuclear power.
The first nuclear-powered ship for carrying cargo and passengers was
the \ind{NS Savannah}, launched in 1962 as part of
\index{Eisenhower, D.D.}\ind{President Dwight D.\ Eisenhower}'s
{\tem\ind{Atoms for Peace}\/} initiative (\figref{Savannah}).
% tonnage 13600 GRT, 9900 DWT (long tons), length 182m, beam 23.8m
Powered by one 74-MW nuclear reactor driving a 15-MW motor, the Savannah
had a service speed of 21\,knots
(39\,km/h) and could carry 60 passengers and 14\,000\,t of cargo.
% 20300hp at the propellor
% 74MW/(21 knots * 14000 tons) in kWh/(ton * km)
% 0.135907495 kWh / (ton * km)
% 74MW/(21 knots * 60 ) in kWh/( km) = 31.7117488 kWh / km
% 74MW/(21 knots * 60 ) in kWh/( km) = 3171.17488 kWh / (100 pkm)
% crew: 124.
That's a cargo transport cost of 0.14\,kWh per ton-km.
% assuming reactor was going full blast
She could travel
500\,000\,km
% 300\,000 miles
without refuelling.
%% png2ps NSsavannah-1962c.{png,eps}
%%%%%%%%%%%%
% nuclear ships
% The icebreaker Lenin was the world's first nuclear-powered surface vessel (20,000 dwt) and remained in service for 30 years
% a series of larger icebreakers, the six 23,500 dwt Arktika-class, launched from 1975. These powerful vessels have two 171 MW OK-900 reactors delivering 54 MW at the propellers and are used in deep Arctic waters. The Arktika was the first surface vessel to reach the North Pole, in 1977.
% The 22,000 tonne US-built NS Savannah, was commissioned in 1962 and decommissioned eight years later. It was a technical success, but not economically viable. It had a 74 MWt reactor delivering 16.4 MW to the propeller. The German-built 15,000 tonne Otto Hahn cargo ship and research facility sailed some 650,000 nautical miles on 126 voyages in 10 years without any technical problems. It had a 36 MWt reactor delivering 8 MW to the propeller. However, it proved too expensive to operate
% all powered by LEU.
% NS Sevmorput
% delivering 32.5 propeller MW from the 135 MWt reactor
% Naval reactors usually run on HEU. They are PWRs.
% Charles de Gaulle, commissioned in 2000, has two PWR units driving 61 MW Alstom turbines and the system can provide 5 years running at 25 knots before refuelling.
% Arktika class icebreakers use two nuclear reactors of 171 MW each, 30-40% enriched fuel and 3-4 year refuelling interval. They drive steam turbines and each produce up to 33 MW (44,000 hp) at the propellers, though overall power is 54 MW.
% http://www.uic.com.au/nip32.htm
There are already many nuclear-powered ships, both military and civilian.
\ind{Russia} has ten nuclear-powered \ind{ice-breaker}s, for example, of which
seven are still active. \Figref{Yamal} shows the
nuclear \ind{ice-breaker} \ind{Yamal},
which has two 171-MW
reactors, and motors that can deliver 55\,MW\@.
% ``eco-boat''
% World record circumnavigation of the globe - 60 d 23 m 49 s june 2008
% http://www.earthrace.net/ 4man crew
% killed one fisherman in guatemala
% ``one of the most eco-friendly boats ever made''
% ``with the ever-present noise, we're always wearing hearing
% protection''
% from captains log in guardian article
% Its two 540hp engines are
% `` quantum leap forward in terms of both efficiency and emissions, ``
% Huey helicopter 14.6m diameter rotor
% http://www.bellhelicopter.com/en/aircraft/military/bellHueyII.cfm
% Range 496km, fuel 799 litres, 11 pax, speed 205km/h
% 7990kWh / 4.96 / 11
% 7990 / 4.96 / 11 = 146 kWh per 100 pkm
% Mini E
% claims http://www.engadget.com/2008/10/18/mini-e-finally-official-500-available-soon-for-us-test-drivers/
% to have 150 mile range off its 35 kWh lithium-ion battery pack,
% 35 kWh / 150 miles in kWh per (100 km)
% that is 14.5 kWh per 100 km
\section{``Hang on! You haven't mentioned magnetic levitation''}
\label{chTrainMaglev}
%A maglev train coming out, Pudong International Airport, Shanghai
% Alex Needham
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/magShanghaiM.eps}}}\\
\end{tabular}
\end{center}
\caption[a]{
A maglev train at Pudong International Airport, Shanghai.
\begin{quote}
``driving without wheels; flying without wings.''
\end{quote}
Photo by Alex Needham.
}\label{figMagL}
}%
The German company, Transrapid, which made the maglev
train for
% Germany and
Shanghai, China (\figref{figMagL}), says:
%\begin{quote}
``The Transrapid Superspeed Maglev System is unrivaled when
it comes to noise emission, energy consumption, and land use.
The innovative non-contact transportation system provides mobility
without the environment falling by the wayside.''
% \end{quote}
Magnetic levitation is one of many technologies
that gets hyped up when people are discussing energy issues.
%% http://home.wangjianshuo.com/archives/20030809_pudong_airport_maglev_in_depth.htm
%% It´s impressive the maglev, but don't forget that it is only a thirty quiulometers line. The TGV has 2.000 km of passanger transportation lines since 1979 whithout accidents, operating in speeds about 300/330 km per hour, whit a record of 512 km/h. It is not a experimental operation !
%top speed is 431 km/h for the shanghai line
%(30 km long)
% see also the txt file in my images directory for excellent german numbers
% http://www.transrapid.de/cgi-tdb/en/basics.prg?session=9be8fa13451ed8b9&a_no=46
% The Transrapid Superspeed Maglev System is unrivaled when it comes to noise emission, energy consumption, and land use. The innovative non-contact transportation system provides mobility without the environment falling by the wayside.
In energy-consumption terms, the comparison with other fast trains is
actually not as flattering as the hype suggests.
The Transrapid site compares the Transrapid with
the InterCityExpress (ICE), a high-speed electric train.\nlabel{pMaglev}
\begin{oldcenter}
\begin{tabular}{ll} \toprule
\multicolumn{2}{c}{{{Fast trains compared }}} \\
\multicolumn{2}{c}{{{ at 200 km/h (125mph)}}} \\ \midrule
Transrapid & 2.2\,kWh per 100 seat-km\\
ICE & 2.9\,kWh per 100 seat-km\\
\bottomrule
%ICE & 29 Wh per seat-km\\
%Transrapid & 22 Wh per seat-km\\ \bottomrule
\end{tabular}
\end{oldcenter}
%ICE at 200 km/h (125mph) = 29 Wh per seat-km
%Transrapid = 22
%
%ICE at 300 km/h: 51
%Transrapid 34
%
%at 400 km/h: transrapid = 52 Wh/seat-km
%
%because: high efficiency motor,
%low weight, low aerodynamic resistance.
% http://www.transrapid.de/cgi-tdb/en/basics.prg?session=9be8fa13451ed8b9&a_no=47
The main reasons why maglev is slightly better than the ICE
are:
the magnetic propulsion motor has high efficiency;
the train itself has low mass, because most of the propulsion system
is in the track, rather than the train; and more passengers
are inside the train because space is not needed for motors.
Oh, and perhaps because the data are from the maglev company's website, so are
bound to make the maglev look better!
% see _maglev.tex for
% \subsection{Non-energy reasons for being interested in maglev}
% Energy consumption for levitation and guidance purposes equates to approximately 1.7 kW/t.
% http://en.wikipedia.org/wiki/Transrapid/German#Energy_requirements
% Total vehicle weight: 110
% metric
% \tonnes\ (2 cars).
% 90 seats per car
% 55 \tons\ per car. (Weight per seat = 600\,kg.)
%In china it is 5 cars I think
% but the above is for 2 cars.
%The train could also carry cargo, up to 15 tons per car.
%See also \myurl{http://www.maglev2000.com/}
Incidentally, people who have seen the Transrapid
train in Shanghai tell me that at full speed it is ``about as quiet
as a jet aircraft.''
% Georg Heidenreich
%% See also driving.tex / train.tex (all cut)
%% Should I put magnetic levitation here or leave it in the myths chapter?
%\section{Bicycles}
%\label{ch.bike}
%\input{bikes.tex}
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{p1percent}]
{\nqs{A widely quoted statistic says
``Only 1\% of fuel energy in a car goes into moving the driver.''
}}
In fact the percentage in this myth
varies in size as it commutes around the urban community.
Some people say ``5\% of the energy goes into moving the driver.''
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm%
\epsfbox{../../images/GWizRally/rally1.JPG.eps}%
}}\\
{\mbox{\epsfxsize=53mm%
\epsfbox{../../images/GWizRally/rally2.JPG.eps}%
}}\\
%{\mbox{\epsfxsize=53mm%
%\epsfbox{../../images/GWizRally/rally3.JPG.eps}%
%}}\\
\end{tabular}
\end{center}
\caption[a]{Nine out of ten vehicles in London are G-Wizes.
(And 95\% of statistics are made up.)
}\label{GWizRally}
}%%%
Others say ``A mere
{\em three tenths of 1 percent\/} of fuel energy goes into moving the driver.''
%%%
\tinyurl{4qgg8q}{http://www.newsweek.com/id/112733/output/print}
My take, by the way, is that none of these statistics is correct or
helpful.
\item[\npageref{pBikeS}]
{\nqs{The bicycle's performance is about the same as the eco-car's.
}}
Cycling on a single-person bike costs about 1.6\,kWh per 100\,km, assuming a speed of
20\,km/h.\index{transport!efficiency!bicycle}
For details and references, see \chref{ch.car2}, \pref{bikeref}.
% {ch.transport2}.
\item[\npageref{pLST}]
{\nqs{The
8-carriage stopping train from Cambridge to London}}
(\figref{fig.stoptrain})
weighs
% 2 * 137.35 tonnes. Each ordinary carriage is 30 tonnes. Power car is
% 50 tonnes. Second class carriages seat 79. Mixed seat 46 second+22first
% length 2 * 80.72m, width 2.82m.
% seats: 270*2 second + 22*2 first
% 540 + 44
275\,tonnes, and can carry 584 passengers seated.
% I'd estimate an additional 21 * 8 standing on peak trains. = 168.
% This is the class 317/1 with many banks of seats 5 wide.
Its maximum speed is 100\,mph (161\,km/h), and the power output is 1.5\,MW\@.
If all the seats are occupied, this train at top speed
consumes at most\index{transport!efficiency!train}
\eccol{1.6\,kWh per 100 passenger-km}.
%
% 1500kW / (161 km/h )/584 in kWh/km
\item[\npageref{pTube}]
{\nqs{London Underground}}.
A Victoria-line train consists of four 30.5-ton and
four 20.5-ton cars
(the former carrying the motors).
Laden, an average train weighs 228 tons.
% source D T Catling 1966
The maximum speed is 45 mile/h.
% According to Catling's model,
% the energy requirement is about 400\,kWh per round trip,
% round trip time 2500 seconds. Line was 10.1 miles long.
% At each end, the train stops for 90 seconds;
% at each intermediate station, the stop time is 30s or 20s.
% Average speed is 29\,mph including
% turnaround at ends.
The average speed is 31\,mph.
% omitting turnaround at ends.
% 30\,mph is the average speed
% quoted in Catling.
% The time between trains is 90 seconds.
% The trains are average loaded (25 tons of passengers)
% from Seven Sisters to Walthamstow (2 miles)
% and crush loaded for the other 8 miles.
% 25 tons of passengers means
% I weigh 78 kilograms
% assume 70 is average.
% 1 ton is 907 or 1016 kg (latter is imperial)
% 357 passengers average loaded, 47 per car.
A train with most seats occupied carries about 350 passengers;
crush-loaded, the train takes about 620.
% I guess crush-loaded means 78 per car, 624 total.
% So the passenger miles delivered for 400\,kWh is:
%% 624*8 + 357*2
%% 5706 passenger miles per 400 kWh
%% 70 Wh per passenger mile
%% 43.55
%% 44 Wh per km.
%% 4400 Wh per 100 passenger km.
The energy consumption at peak times is about
\eccol{4.4\,kWh per 100 passenger-km}
\citep{Catling1966}.
\item[\npageref{pHST}]
{\nqs{High-speed train}}.
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}cc}
%% {\small\sc Consumption}& {\small\sc Production}\\
\mbox{\epsfbox{metapost/stacks.204}} & \\
%% {\mbox{\epsfbox{crosspad/cars3.ps}}} & ? \\
\end{tabular}
\end{center}
% }{
\caption[a]{100\,km in a single-person car,
compared with 100\,km on a fully-occupied electric high-speed train.}
}
%\subsection{Intercity trains}
% {Intercity trains}
A diesel-powered intercity 125 train
(on the right in \figref{IC125})
weighs 410\,tons.
% and uses a power of 3.4\,MW
When travelling at 125\,mph,
the power delivered ``at the rail''
is 2.6\,MW\@.
% sounds like 38% is the right efficiency to assume
% engine output 1678kW x2 force is 349 kN
% http://www.dft.gov.uk/pgr/rail/researchtech/research/railemissionmodel
% http://www.inrets.fr/infos/cost319/MEETDeliverable17.PDF
% Each second-class carriage can carry about 74 passengers.
% (It used to be 64 seats to a carriage, but they have
% squashed us up.)
% First-class carriages can carry about 48 passengers.
The number of passengers in a full train
is about 500.
The average fuel consumption is about 0.84\,litres of diesel
per 100 seat-km \tinyurl{5o5x5m}{http://www.cambridgeenergy.com/archive/2007-02-08/cef08feb2007kemp.pdf}, which is a transport cost of
% and the power per person is about 7\,kW\@.
% The transport efficiency is
about \eccol{9\,kWh per 100 seat-km}.
% was 3.3
% about 5.44\,kWh per 100 seat-miles.
% pr 3400.0/500 / 125.0 * 100.0 / (1.636)
% 3.32518337408313
%
%intercity 125: 410 tonnes
%\myurl{http://en.wikipedia.org/wiki/British_Rail_Class_43_%28HST%29}
%\myurl{http://en.wikipedia.org/wiki/British_Rail_Class_43_\%28HST\%29}
%% \durl{http://en.wikipedia.org/wiki/British\_Rail\_Class\_43\_\%28HST\%29}
%
% 2 diesel power cars each engine 1680 kW (1.7MW)
% total 3360kW.
%
% power at rail 1320 kW each
% total 2640 kW
%
%force: 46kN (at 125 mph that is 2570 kW TICK!)
%brake force 350 kN
%70 tonnes each
%4500 litres fuel
% ELECTRIC TRAINS data -
% http://www.cambridgeenergy.com/archive/2007-02-08/cef08feb2007kemp.pdf 3kWh per 100seatkm
%%% http://en.wikipedia.org/wiki/TGV
% Some similar large high-speed trains:
% the 300 km/h Eurostar has 12.24\,MW power output
% and weighs 752 tons.
%
% BUSES CARRY 9 passengers and do 5.6 miles per gallon
%%% ======================
%
%The British Rail Class 91
%is an electric locomotive which travels
%at 140 mph (225 km/h)
% \myurl{http://en.wikipedia.org/wiki/British_Rail_Class_91}
%\myurl{http://en.wikipedia.org/wiki/British\_Rail\_Class\_91}
% and uses 4.5\,MW.
%6090 hp = 4540 kW
% class 91
% engine weighs 84 t
% ((4.5 MW) / (225 (km / hour))) / 500 = 4 kWh per (100 km)
The Class 91 electric train (on the left
in \figref{IC125})
travels at 140\,mph (225\,km/h)
and uses 4.5\,MW\@.
% 4.5 MW / (225 km/hour) in kWh per (100 km)
% That corresponds to an energy cost of \eccol{4\,kWh per 100 seat-km} at top speed.
According to Roger Kemp,\index{Kemp, Roger}
this train's average energy consumption is
\eccol{3\,kWh per 100 seat-km}
\tinyurlb{5o5x5m}{http://www.cambridgeenergy.com/archive/2007-02-08/cef08feb2007kemp.pdf}.
% and 16 g COO per seat km.
% whereas the class 43 HST does 25 g per seat km
The government document
\tinyurl{5fbeg9}{http://www.cfit.gov.uk/docs/2001/racomp/racomp/pdf/racomp.pdf}
says that east-coast mainline
and west-coast mainline
trains both consume about 15\,kWh per km (whole train).
The number of seats in each train is 526 or 470 respectively.
So that's \eccol{2.9--3.2\,kWh per 100 seat-km}.
%(Incidentally they say that the ICE ranges from 20 to 33 kWh per km (whole train);
%and that there are TGV lines with energy consumptions of 17, 19, and 22 kWh/km, depending
%on the route. All these figures take into account realities of slopes and tunnels.)
\item[\npageref{pRidley}]
{\nqs{the total energy cost of all \index{London Underground}{London}'s underground
trains, was
{15\,kWh per 100\,\pkm}. \ldots\
The energy cost of all London buses
was {32\,kWh per 100\,\pkm}}}.
Source:
\tinyurl{679rpc}{http://www.tfl.gov.uk/assets/downloads/environmental-report-2007.pdf}.
Source for train speeds and
bus speeds: \cite{RidleyCatling1982}.
% In 2006--7, the underground system's
% carbon emissions were 68.9\,g\,\COO\ per \pkm. Energy consumption was
% 150\,Wh per \pkm. 15\,kWh per 100\,\pkm.
% Electricity consumption was 1139\,GWh,
% including stations, depots, traction,
% and offices.
% They claim to get 16.1\% of their energy
% (all their non-traction electricity)
% from renewables. The official grid factor they
% use is 523\,g\,\COO\ per \kWhe.
% 85\% of the electrical energy they use powers the trains.
% The road fleet for London Underground maintenance
% (1176 vehicles)
% consumed 2\,622\,224\,l of fuel.
% ``6571 t COO''
% water: 570 M litres of water in 2006-7
% total CO2: 522836t
% 68.9 g/pkm
% So total pkm = 522836e6/68.9 = 7.5883e+09
% and elec/pkm = 15.01 kWh / pkm
% http://www.tfl.gov.uk/assets/downloads/environmental-report-2007.pdf
% CO2 per pkm: (g) Energy per pkm
% underground: 65 1221e6 / (519710e6/65 ) = 0.15271 15.2 kWh/100pkm
% bus 82 2384e6 / (615344e6/82) = 0.3177 31.8 kWh/100pkm
% DLR 74
% croydon tramlink 42
% total all eletricity and fuel: 5.8b kWh
% of which liquid fossilfuels and NG and biodiesel
% are 74.4+1.6+1.5 %
% http://www.tfl.gov.uk/assets/downloads/corporate/annual-report-and-statement-of-accounts-06-07.pdf
% 2006-7
% London UNderground total energy 1221 GWh CO2: 519710t
% London bus network 2384 GWh CO2: 615344t
% inc bus stops, shelters, ticket machines
% Croydon tramlink 11 GWh 5391
% DLR 45 GWh 22671
% energy conversion factors
% www.berr.gov.uk/energy/statistics/publications/dukes/page39771.html
\item[\npageref{pCroy}]
{\nqs{Croydon Tramlink}.} \par
\myurlb{www.tfl.gov.uk/assets/downloads/corporate/TfL-environment-report-2007.pdf}{http://www.tfl.gov.uk/assets/downloads/corporate/TfL-environment-report-2007.pdf},
%
\myurlb{www.tfl.gov.uk/assets/downloads/corporate/London-Travel-Report-2007-final.pdf}{http://www.tfl.gov.uk/assets/downloads/corporate/London-Travel-Report-2007-final.pdf},
\myurlb{www.croydon-tramlink.co.uk}{http://www.croydon-tramlink.co.uk/}.
\marginfig{
%\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=51mm\epsfbox{../../images/tramIstan.eps}}}\\%
{\mbox{\epsfxsize=51mm\epsfbox{../../images/PragueTram.eps}}}%
\\
\end{tabular}
% \end{center}
\caption[a]{Trams work nicely
% Public transport works
in Istanbul and Prague too.
}\label{TramIstan}
}
\item[\npageref{pCycleprovision}]
{\nqs{\ldots\ provision of excellent
cycle facilities \ldots } }
The \UK\ street design guide
[\myurlb{www.manualforstreets.org.uk}{http://www.manualforstreets.org.uk/}]
encourages designing streets to make 20 miles per hour the natural
speed.
See also \cite{CyclePlan}.
% Transport for London (TfL) this week released figures which show an increase of 91% in the number of people cycling on London's major roads since 2000.
% http://www.lcc.org.uk/index.asp?PageID=1157
\item[\npageref{pConCharg}]
{\nqs{A fair and simple method for handling
congestion-charging}}.
I learnt a brilliant way to
automate congestion-charging\index{congestion charging}
from {Stephen Salter}\index{Salter, Stephen}.
A simple daily congestion charge, as levied in London, sends only a crude signal
to drivers; once a car-owner has decided to pay the day's charge
and drive into a congestion
zone, he has no incentive to drive {\em{little}\/} in the zone.
Nor is he rewarded with any rebate
if he carefully chooses routes in the zone that are not congested.
Instead of having a centralized authority
that decides in advance when and where the congestion-charge zones are, with expensive
and intrusive
monitoring and recording of vehicle movements into and within all those zones,
Salter has a simpler, decentralized, anonymous method of charging drivers
for driving in heavy, slow traffic, wherever and whenever it actually exists.
The system would operate nationwide. Here's how it works.
We want a device
that answers the question ``how congested is the traffic I am driving
in?'' A good measure of congestion is ``how many other active vehicles are close to
mine?''
In fast-moving traffic, the spacing between vehicles is larger than slow-moving traffic.
Traffic that's trundling in tedious queues is the most densely packed.
The number of nearby vehicles that are active can be sensed
anonymously
% approximately measured
by fitting in every vehicle a radio transmitter/receiver (like a very cheap mobile phone)
that transmits little radio-bleeps at a steady rate
whenever the engine is running,
and that counts the number of bleeps it hears from other vehicles.
The congestion charge would be proportional to the number of bleeps received;
this charge could be paid at refuelling stations whenever the vehicle is refuelled.
The radio transmitter/receiver would replace the current UK road tax disc.
%%% REGEN
\item[\npageref{pHydrauFly}]
{\nqs{hydraulics and flywheels salvage
at least 70\% of the braking energy.}}
% http://en.wikipedia.org/wiki/Hydraulic_accumulator
Compressed air is used for regenerative braking in trucks;
{\myurl{eaton.com}} say ``hydraulic launch assist'' captures 70\% of the kinetic energy.
\tinyurl{5cp27j}{http://www.eaton.com/EatonCom/ProductsServices/Hybrid/SystemsOverview/HydraulicHLA/index.htm}
The flywheel system of \myurl{flybridsystems.com} also captures 70\%
of the kinetic energy.
\myurlb{www.flybridsystems.com/F1System.html}{http://www.flybridsystems.com/F1System.html}
{\nqs{Electric regenerative braking salvages 50\%.}} Source: \cite{E4tech}.
% http://www.eaton.com/EatonCom/ProductsServices/Hybrid/SystemsOverview/HydraulicHLA/index.htm
%Hydraulic regenerative braking improves large-truck fuel economy
%A new hydraulic regenerative braking system captures energy normally lost during braking, stores it, and re-uses it
%By Bruce Wiebusch, Regional Editor -- Design News, June 17, 2002
% http://www.designnews.com/article/2407-Hydraulic_regenerative_braking_improves_large_truck_fuel_economy.php
%Detroit %G—%@ Ford Motor Company and Eaton Corp. recently introduced a regenerative braking system called the hydraulic launch assist (HLA). The system is designed to improve fuel economy in large trucks during city driving by an estimated 25 to 35%. The HLA system featured on the Ford's new F350 Tonka concept truck recovers energy normally lost during deceleration and converts it to hydraulic pressure in an accumulator, where it is available as a source of energy during the vehicle's next acceleration.
\item[\npageref{LiIonP}]
{\nqs{
Electric batteries capable of delivering 60\,kW
would weigh about 200\,kg.
}}
Good lithium-ion batteries have a specific power of 300\,W/kg
\citep{LiIonPower,BattPower}.
\item[\npageref{car168}]
{\nqs{the average new car in the UK emits 168\,g \COO\ per km.}}
This is the figure for the year 2006 \citep{KingII}.\index{data!emissions of cars}
The average emissions of a new passenger vehicle
in the USA were 255\,g per km \citep{KingII}.
\item[\npageref{pPrius}]
{\nqs{The \ind{Toyota Prius} has a more-efficient
engine}}. The \ind{Prius}'s \ind{petrol engine}
uses the \ind{Atkinson cycle}, in contrast to
the conventional \ind{Otto cycle}.
By cunningly
mixing electric power and petrol
power as the driver's demands change,
the Prius gets by with a smaller engine than is normal in a car of its
weight, and converts petrol to work more efficiently than a
conventional petrol engine.
% \item[\pageref{pCNW}]
% {\sc the Honda Accord Hybrid has an Energy Cost per Mile of
%\$3.29 while the conventional Honda Accord is
%\$2.18}.
%source -- CNW Marketing Research Inc. as reported at Auto Spectator.
\item[\npageref{hybrid20}]
{\nqs{Hybrid technologies give fuel savings of
20\% or 30\%}}.
For example, from Hitachi's research report describing
hybrid trains \citep{HitachiHybridTrain}:
high-efficiency power generation and
regenerative braking
are ``expected to give fuel savings
of approximately 20\% compared
with conventional diesel-pow\-er\-ed trains.''
\item[\npageref{pEddRang}]
%Range]
{\nqs{Only 8.3\%
of commuters travel\index{data!commuting}\index{commuting, data}
over 30\,km to their workplace.}}
Source: \cite{EddingtonT}.
The dependence of the range of an electric car on the size of
its battery is discussed in \chref{ch.cars2} (\pref{ch.cars2Range}).
\item[\npageref{lotsE}] {\nqs{Lots of electric vehicles}}.
They are all listed below, in no particular order.
Performance figures are mainly from the manufacturers.
As we saw on \pref{pWizClaim}, real-life performance
doesn't always match manufacturers' claims.
\item[Th!nk]
Electric cars from \ind{Norway}.
The five-door \index{Think}{Th!nk} Ox
has a range of 200\,km. Its batteries weigh 350\,kg, and the car weighs
1500\,kg in total.
Its energy consumption is
approximately \eccol{20\,kWh per 100\,km}.
% Charging the TH!NK Ox from zero to a fully charged state from a standard 230V/16A European outlet, will take approximately 12 hours using the onboard charger.
% 12 * 230 * [13 16] / 2 / 1e3 -> 18 or 22 kWh per 100 km
% The four-seat, two-door \index{Think}{Th!nk} City
% has a range of 170\,km and
% weighs 1113\,kg.
% Takes 10 h to charge at 230V, 14A. That's 32kWh
% Range 203km of urban drive cycle.
% 170 km of IEC
% Its energy consumption is
% approximately \eccol{19\,kWh per 100\,km}.
% 230*14 * 10/1e3
%ans = 32.200
%octave:3> 32.2/1.70
%ans = 18.941
\myurlb{www.think.no}{http://www.think.no/}
% thinkox_007.jpg
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm%
\lowres{%
\epsfbox{../../images/thinkox_007S.eps}%
}{%
\epsfbox{../../images/thinkox_007M.eps}%
}
}}%
\\
\end{tabular}
\end{center}
\caption[a]{\index{Think}{Th!nk} Ox.
Photo from \myurlb{www.think.no}{http://www.think.no/}.
}\label{thinkox}
}
\item[Electric \ind{Smart Car}] ``The electric version is powered by a 40\,bhp
motor, can go up to 70 miles,
% before the battery goes flat
and has a
top speed of 70\,mph.
%
Recharging is done through a standard electrical power point and costs
about \pounds1.20, producing the equivalent of 60\,g/km of carbon
dioxide emissions at the power station.
% Smart says.
[\cf\ the equivalent petrol-powered Smart: 116\,g/km.]
%
% That's a far lower figure than any petrol or diesel car in the world.
%
A full recharge takes about eight hours, but the battery can be topped
up from 80\%-drained to 80\%-charged in about three-and-a-half hours.''
[\myurlb{www.whatcar.com/news-article.aspx?NA=226488}%
{http://www.whatcar.com/news-article.aspx?NA=226488}]
%% http://www.carpages.co.uk/citroen/citroen_alternative_fuel_new_look_berlingos_28_01_03.asp
%% http://www.citroenet.org.uk/passenger-cars/psa/berlingo/berlingo-electrique.html
\item[Berlingo Electrique 500E,] an urban delivery van (\figref{Berlingo}),
has 27 nicad batteries and a 28\,kW motor. It can transport a payload of
500\,kg.
Top speed: 100\,km/h; range: 100\,km. \eccol{25\,kWh per 100\,km}.
(Estimate kindly supplied by a
Berlingo owner.)
% (20 kWh) / (50 miles) = 0.248548477 kWh per km
% (60\,mph) 60 miles.
%% 9 hour charge time, from a 13A socket. Does that mean 27kWh for 60mi?
%% fast charge 10min gives 20km range ie 0.5kWh
%% so that is a claim of 2.5kWh per 100km??? NO, requires 150A socket!
\tinyurl{4wm2w4}{http://www.citroenet.org.uk/passenger-cars/psa/berlingo/berlingo-electrique.html}
%% enthusiast site:
%% http://www.berlingo-e.co.uk/
%* RMS - Berlingo-E [2008-04-18 19:01]:
%% Hi David,
%
% I think it's about 400Wh/mile, with a full charge taking around 20kWh.
%
% A full charge generally gives me around 50 miles (80km) which should mean
% around 25kWh per 100km (I think!).
%
% Of course, the range, and therefore Wh/mile, can vary quite a lot.
% For example, driven foot-to-the-floor at high speeds and braking instead of
% using regen I would only get about 30 miles. Driven very, very carefully,
% the range can extend to about 60 miles.
%
% Hope that helps.
%
% I've had a quick look at your site, and when I get more time, I'll read your
% book :o)
%
% Best regards,
% Robin.
%
%% \cite{biofuels08} says that electric cars do 72 MJ/100km (20kWh/100km)
%% whereas diesel engine does 172.1 MJ/100km (48kWh/100km)
\item[\ind{i MiEV}] This electric car
% from Mitsubishi
is projected to have a range of 160\,km with a 16\,kWh battery
pack. That's \eccol{10\,kWh per 100\,km} -- better than the G-Wiz -- and
whereas it's hard to fit two adult Europeans
in a G-Wiz, the Mitsubishi prototype has four doors and four
full-size seats (\figref{fig.Miev}).
\tinyurl{658ode}{http://www.greencarcongress.com/2008/02/mitsubishi-moto.html}
% http://www.treehugger.com/files/2007/03/mitsubishi-delivers-miev.php
% got original image from mitsu site (djcmackay mitsumitsu)
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/MIEV_1.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/i_MiEV_1_M.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{The i MiEV from Mitsubishi Motors Corporation.
%% Dimensions (L x W x H) 3395 x 1475 x 1600 mm
%% Vehicle weight 1080 kg
% top speed 130 kph
It has a 47\,kW motor, weighs 1080\,kg, and has a top speed of 130\,km/h.
}\label{fig.Miev}
}
\item[EV1]
The two-seater \ind{General Motors} EV1\index{GM EV1}\index{EV1} had a range of
120 to 240\,km per charge, with nickel-metal hydride batteries holding
26.4\,kWh.
% wikipedia General_Motors_EV1
That's an energy consumption of between \eccol{11} and \eccol{22\,kWh per 100\,km}.
% From another source
% http://www.energypolicy.co.uk/Prius%20Presentation%202/Slide%2017.htm
% The \ind{GM EV1} did 6\,km per kWh, or 17\,kWh per 100\,km.
% It had a drag coefficient of 0.19 and $c_dA = 0.36\,$m$^2$. % GM EV1
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm%
\epsfbox{../../images/lightning.eps}%
}}
\end{tabular}
\end{center}
\caption[a]{\index{Lightning car}{Lightning}:
\eccol{11\,kWh per 100\,km}. Photo from
\myurlb{www.lightningcarcompany.co.uk}{http://www.lightningcarcompany.co.uk/}.
}\label{lightning}
}%
\item[{Lightning}] (\figref{lightning})
-- has four 120\,kW brushless motors, one on each wheel,
regenerative braking, and fast-charging \ind{Nanosafe} \ind{lithium titanate}
% altairnano
batteries.
A capacity of 36\,kWh gives a range of 200\,miles (320\,km).
That's \eccol{11\,kWh per 100\,km}.
\item[\ind{Aptera}]
This
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/aptera1.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{The \ind{Aptera}.
{\eccol{6\,kWh per 100\,km}}.
Photo from \myurlb{www.aptera.com}{http://www.aptera.com/}.
}\label{fig.aptera}
}%
fantastic slippery \ind{fish}\index{car!fish} is a two-seater
vehicle, said to have an energy cost of
{\eccol{6\,kWh per 100\,km}}.
It has a \ind{drag coefficient} of 0.11 (\figref{fig.aptera}).
Electric and hybrid models are being developed.
\item[\ind{Loremo}]
Like the Aptera, the Loremo (\figref{fig.loremo}) has a small frontal
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/loremo4.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{The \ind{Loremo}.
{\eccol{6\,kWh per 100\,km}}.
Photo from \myurlb{evolution.loremo.com}{http://evolution.loremo.com/}.
}\label{fig.loremo}
}%
area and small drag coefficient (0.2)
and it's going to be available in both fossil-fuel and electric
versions. It has two adult seats and two rear-facing kiddie seats.
The Loremo EV will have lithium ion batteries and
is predicted to have an energy cost of
{\eccol{6\,kWh per 100\,km}}, a top speed of 170\,km/h,
and a range of 153\,km. It weighs 600\,kg.
\item[eBox]
The eBox
% http://www.acpropulsion.com/ebox/specifications.htm
% http://www.acpropulsion.com/ebox/specifications.htm
has a \ind{lithium-ion} \ind{battery} with a capacity of 35\,kWh
and a weight of
% 625\,lb;
280\,kg; and a range of 140--180\,miles.
Its motor has a peak power of 120\,kW and
can produce a sustained power of 50\,kW\@.
% Normal charge time is 5\,h.
% Vehicle-to-grid capability is already built in.
% Efficiency:
Energy consumption:
% at best 0.19\,kWh/mile, i.e., 12\,kWh per 100\,km.
%% perhaps 5 passengers?
\eccol{12\,kWh per 100\,km}.
% if carrying a single occupant;
% 3\,kWh per 100\,seat-km if four seats are used.
% (Same as a high-speed train.)
\item[\ind{Ze-0}]
% http://www.nicecarcompany.co.uk/ze-0.html
A five-seat, five-door car.
Maximum speed: 50\,mph.
Range: 50\,miles.
Weight, including batteries: 1350\,kg.
Lead acid batteries with capacity of 18\,kWh.
Motor: 15\,kW\@.
% 18kWh of battery? charger power 2.5kW charge time 8-10h.
% so that makes 18kWh sound right.
% 18kWh / 50 miles in kWh per km
\eccol{22.4\,kWh per 100\,km}.
% CUTTABLE from here to end of MyCar
\item[\ind{e500}]
% http://www.nicecarcompany.co.uk/e500.html
An Italian Fiat-like car, with two doors and 4 seats.
Maximum speed: 60\,mph.
Range in city driving: 75 miles.
Battery: lithium-ion polymer.
\item[\ind{MyCar}]
% http://www.nicecarcompany.co.uk/my-car.html
The MyCar is an Italian-designed two-seater.
Maximum speed: 40\,mph.
Maximum range: 60 miles.
Lead-acid battery.
\item[\ind{Mega City}]
% 11500 pounds
% 40mph, 60mile range
% 65 miles at stabilized speed on flat road.
% 185 Wh per mile
A two-seater car with a maximum continuous power of 4\,kW
and maximum speed of 40\,mph:
% http://www.nicecarcompany.co.uk/mega-city.html
\eccol{11.5\,kWh per 100\,km}.
Weight unladen (including batteries) -- 725\,kg.
% AGM lead batteries
The lead batteries have a capacity of 10\,kWh.
% charger 1.5kW charge time 8-10h
% Battery self-discharge: about 8\% per week.
% ``power 36kW ``?
\item[\ind{Xebra}]
Is claimed to have a 40\,km range from a 4.75\,kWh charge.
% \newlineone
\eccol{12\,kWh per 100\,km}.
Maximum speed 65\,km/h.
Lead-acid batteries.
\item[\ind{TREV}]
The \ind{Two-Seater Renewable Energy Vehicle}
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/TREVcar.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{The \ind{TREV}.
{\eccol{6\,kWh per 100\,km}}.
Photo from \myurlb{www.unisa.edu.au}{http://www.unisa.edu.au/}.
}\label{fig.TREV}
}%
(TREV) is a prototype developed by the
\ind{University of South Australia} (\figref{fig.TREV}).
This \ind{three-wheeler}
has a range of 150\,km, a top speed of 120\,km/h, a mass of 300\,kg,
and lithium-ion polymer batteries weighing 45\,kg.
During a real 3000\,km trip, the energy consumption was
{\eccol{6.2\,kWh per 100\,km}}.
\item[\ind{Venturi Fetish}]
Has a 28\,kWh battery, weighing 248\,kg.\index{Fetish}
The car weighs 1000\,kg.
Range 160--250\,km.
That's \eccol{11--17\,kWh per 100\,km}.
\par
\myurlb{www.venturifetish.fr/fetish.html}{http://www.venturifetish.fr/fetish.html}
\item[Toyota RAV4 EV]
This vehicle -- an all-electric \ind{mini-SUV}\index{SUV, electric}%
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/rav4-ev.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{\ind{Toyota RAV4 EV}.\index{RAV4}
Photo by Kenneth Adelman,
\myurlb{www.solarwarrior.com}{http://www.solarwarrior.com/}.
}\label{rav4ev}
}
--
was sold by Toyota between 1997 and 2003 (\figref{rav4ev}).
% http://en.wikipedia.org/wiki/Toyota_RAV4_EV
The RAV4 EV has
24 12-volt 95Ah NiMH batteries capable of storing 27.4\,kWh of energy;
% charge time 5 h
and a range of
% 80 to 120 mi (126 miles according to another site)
130 to 190 km.\index{electric vehicle!RAV4}
So that's an energy consumption of \eccol{14--21\,kWh per 100\,km}.
The RAV4 EV was popular with \ind{Jersey Police} force.
%% use image adelman_rav4
%% no use http://www.solarwarrior.com/
%% rav4
\item[\ind{Phoenix SUT}] -- a five-seat ``sport utility truck''
made in California --
%%
has a range of ``up to 130\,miles'' from a 35\,kWh lithium-ion
battery
pack. (That's \eccol{17\,kWh per 100 km}.)
The batteries can be recharged from a special outlet
in 10 minutes.
\myurlb{www.gizmag.com/go/7446/}{http://www.gizmag.com/go/7446/}
%% Nanosafe batteries
%% http://www.phoenixmotorcars.com/
\item[\ind{Modec} \index{delivery vehicle, electric}{delivery vehicle}]
% doing delivery veh for Tesco
Modec carries two tons a distance of 100 miles.
Kerb weight 3000\,kg.
\myurlb{www.modec.co.uk}{http://www.modec.co.uk/}
\item[Smith Ampere]
Smaller delivery van, 24\,kWh lithium ion batteries. Range
``over 100 miles.''
% 50kW elec motor , payload up to 800kg.
\myurlb{www.smithelectricvehicles.com}{http://www.smithelectricvehicles.com/}
\item[Electric minibus]
From \myurlb{www.smithelectricvehicles.com}{http://www.smithelectricvehicles.com/}:
\newlineone
40\,kWh lithium ion battery pack. 90\,kW motor
with regenerative brakes.
Range ``up to 100 miles.''
% 161km
15 seats. Vehicle kerb weight 3026\,kg.
Payload 1224\,kg.
% GVW 4.25t
That's a vehicle-performance
of at best \eccol{25\,kWh per 100\,km}.
If the vehicle is fully occupied,
it could deliver transportation at
an impressive cost of \eccol{2\,kWh per 100\,p-km}.
% 1.657
\item[Electric coach]
The Thunder Sky bus has a range of 180 miles and a recharge time of
three hours.
\myurlb{www.thunder-sky.com}{http://www.thunder-sky.com/}
% http://www.thunder-sky.com/products_en.asp?fid=71&fid2=75
% MODEL:Thunder Sky-EV-2008(43seats) Lithium-ion battery
% top speed 100km/h normal power 90kW, max power 180kW
% 2000 cycles battery 400Ah, single cell voltage 2.5-4.25V. weighs 13kg.
% bus full loaded weight: 15.5 metric tons net weight 11t.
%% 10 seat minibus EV 6700
% normal power 45kW. max power 90kW. max speed 100km/h. 4.7t, laden weight, 6.8t.
% range 280km. 90 cells, each 400Ah at 2.5-4.25V (?).
\item[Electric scooters]
%% http://timesonline.typepad.com/eco_worrier/
%% http://www.vectrix.com/
The \ind{Vectrix}
is a substantial scooter (\figref{vectrix}).
Its battery (nickel metal hydride) has a capacity of
% 30\,Ah,
3.7\,kWh.
It can be driven for up to 68 miles
at 25 miles/h (40 km/h),
on a two-hour charge from a standard electrical socket.
That's 110 km for 3\,kWh,
or \eccol{2.75\,kWh per 100\,km}.
It has a maximum speed of 62\,mph (100 km/h).
It weighs 210\,kg and has a peak power of 20\,kW\@.
\myurlb{www.vectrix.com}{http://www.vectrix.com/}
%``your carbon footprint will still be there, just from a power station
%rather than direct emissions, but so long as you sign up to a green
%energy tariff first
%%(Good Energy and Ecotricity are my
%%recommendations)
%you needn't worry about that.''
%[See the chapter on myths for my views on this quote.]
% Has regen brakes.
% costs 7000 pounds
%(2 hours delivers 80\% charge.)
%Battery voltage 125\,V. Charger is 1.5\,kW.
%Battery life:
%1700 cycles, 10 years,
%50\,000 miles (80\,000 km).
% Peak power of motor: 20\,kW.
%%%%%%%%%%%%%%%%%5555
The ``\ind{Oxygen Cargo}'' is a smaller scooter. It
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Vectrix2.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{Vectrix:
\eccol{2.75\,kWh per 100\,km}. Photo from
\myurlb{www.vectrix.com}{http://www.vectrix.com/}.
% \myurl{http://www.vectrix.com/}
}\label{vectrix}
}%
weighs 121\,kg, has a 38 mile range, and takes 2--3 hours to charge.
Peak power: 3.5\,kW; maximum speed 28\,mph.
It has two lithium-ion batteries and regenerative brakes.
The range can be extended by adding extra batteries, which store about
1.2\,kWh and weigh 15\,kg each.
% own charger is 1kW. battery is 12V, and stores 100Ah, so 1200 Wh
% 2.4kWh total
% The battery capacity is
% 2.4kWh / 38 miles in kWh per km
Energy consumption:
{\eccol{4\,kWh per 100\,km}}.\index{transport!efficiency!electric scooter}
% 3.92
%% end electric vehicles
%% compressed air
\end{notelist}
\newpageone% Sun 2/11/08 there were 3-4 lines space at bottom of page 138
\beginfullpagewidth%
\noindent%
\begin{notelist}
\item[\npageref{compAir}]
{\nqs{the energy-density of compressed-air energy-stores is
only about 11--28\,Wh per kg.}}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% hydrogen
% \tinyurl{2dfgoe}{http://en.wikipedia.org/wiki/Compressed_air_energy_storage}
The theoretical limit, assuming perfect isothermal compression: if
1\,m$^3$ of ambient air is slowly
compressed into a 5-litre container
at 200\,bar, the potential energy stored is
% 583 kJ (or
0.16\,kWh in 1.2\,kg of air.
% mass of air is 1.2kg
In practice, a 5-litre container appropriate for this
sort of pressure weighs about 7.5\,kg if made from steel
or 2\,kg using kevlar or carbon fibre, and
the overall energy density achieved would be about 11--28\,Wh per kg.
The theoretical energy density is the same, whatever the volume
of the container.
% 40 kJ per kg - 100
% is 11.1 Wh/kg - 28
\item[\npageref{pageArnold}]
{\nqs{Arnold Schwarzenegger
\ldots filling up a hydrogen-powered Hummer}}.
{\em Nature} {\bf 438}, 24 November 2005.
I'm not saying that hydrogen will {\em{never}\/} be useful
for transportation; but I would hope that
such a distinguished journal as {\em{Nature}\/}\index{Nature magazine}
would address the hydrogen bandwagon with some critical
thought, not only euphoria.
% Perhaps this quote is relevant:
\myquote{%
% "Our estimates put building a hydrogen
% infrastructure at one trillion dollars...
Hydrogen and fuel cells are not the way
to go. The decision by the Bush
administration and the State of
California to follow the hydrogen
highway is the single worst decision of
the past few years.
}{
James Woolsey, Chairman of the Advisory Board of the US
Clean Fuels Foundation, 27th November 2007.
}
In September 2008,
% 4th
{\tem{The Economist}\/} wrote
% http://www.economist.com/business/displaystory.cfm?story_id=12070722
``Almost nobody disputes that \ldots\
% hybrids are a bridging technology, however, and that
eventually most cars will be powered by batteries alone.''
On the other hand, to hear more from advocates of
hydrogen-based transport,
see the \ind{Rocky Mountain Institute}'s pages about the ``\ind{HyperCar}''
\myurl{www.rmi.org/hypercar/}.
\item[\npageref{pageCUTE}] {\nqs{In the Clean Urban Transport for Europe project
the overall energy required to power the hydrogen buses was
between 80\% and 200\% {\em greater\/} than that of the baseline diesel bus.
}}
Source: \cite{CUTE1,CUTE8}.
% The CUTE project used a Mercedes-Benz Fuel Cell bus.
%% 44kg hydrogen stored at pressure up to 350bar
%% fuel consumption in london (typical) was 23.9 kg
%% per 100 km
%% The efficiency from fuel to traction was 22\%.
%% page 36 of 54
%% Fuel cell losses were 39%, +5.5% in ``power dump''
%% cabin heating 16%
%% auxiliary systems too 13%
\item[\npageref{pBMW}]
{\nqs{Fuelling the hydrogen-powered car made by BMW requires
{\em three times more\/} energy than an average car}}.
Half of the \uk{boot}{trunk} of the BMW ``Hydrogen 7'' car\index{BMW!Hydrogen 7}
is taken up by its 170-litre hydrogen tank, which holds 8\,kg of hydrogen,
giving a range of 200\,km on hydrogen\index{hydrogen!energy cost of}
[\myurlb{news.bbc.co.uk/1/hi/business/6154212.stm}{http://news.bbc.co.uk/1/hi/business/6154212.stm}].
The calorific value of hydrogen % HHV
is 39\,kWh per kg, and the best-practice
energy cost of making hydrogen is 63\,kWh per kg (made up of 52\,kWh of natural
gas and 11\,kWh of electricity) \citep{CUTE1}.
% Electrolysis comes in at 65 kWh/kg, according to same document.
% The NREL document about wind and hydrogen says 53.4 kWh per kg including 2.09kWh/kg
% for compression .
% http://www.hydrogen.energy.gov/h2a_prod_studies.html
% hydrogen production case studies
So filling up the 8\,kg tank has an energy cost of at least 508\,kWh;
and if that tank indeed delivers 200\,km, then the energy cost is
\eccol{254\,kWh per 100\,km}.
% This is more than three times the energy consumption
% of an average European fossil-fuel car, which costs 80\,kWh per 100\,km (\pref{tabCar80}).
\myquote{
The Hydrogen 7 and its hydrogen-fuel-cell cousins are, in many ways, simply flashy distractions.
% produced by automakers who should be taking stronger immediate action to reduce the greenhouse-gas emissions of their cars.
}{
David Talbot, MIT Technology Review
\par \hfill \myurlb{www.technologyreview.com/Energy/18301/}{http://www.technologyreview.com/Energy/18301/}
}
% {FCXHonda}
{\nqs{Honda's fuel-cell car, the FCX Clarity}},
weighs 1625\,kg, stores 4.1\,kg of hydrogen at a pressure of 345\,bar, and
is said to have a range of 280\,miles,
consuming 57 miles of road per kg of hydrogen (91\,km per kg) in a
standard mix of driving conditions
\tinyurl{czjjo}{http://corporate.honda.com/environment/fuel_cells.aspx?id=fuel_cells_fcx},
\tinyurl{5a3ryx}{http://automobiles.honda.com/fcx-clarity/specifications.aspx}.
Using the cost for creating hydrogen mentioned above, assuming
natural gas is used as the main energy source, this car has
a transport cost of \eccol{69\,kWh per 100\,km}.
% http://www.ukwatch.net/blog/merrick_godhaven/honda039s_hydrogen_hype
% see also
% [IPCC Special Report on Carbon Dioxide Capture and Storage, Cambridge University Press, 2005, p 131]
% and http://www.nrel.gov/docs/fy06osti/39534.pdf
% Wind Energy and Production of Hydrogen and Electricity %G—%@ Opportunities for Renewable Hydrogen,
\myquote{
\ind{Honda} might be able to kid \ind{journalist}s into thinking that
\ind{hydrogen car}s are ``zero emission''
but unfortunately they can't fool the climate.
}{
Merrick Godhaven
}
% The model H2 Hummer requires nearly 11,000 BTU of gasoline to travel a single mile
% H2 hummer is what arnold rides
% The H2H puts lipstick on the pig by turning a vehicle whose urban fuel economy is about 10 miles per gallon into a futuristic, alternatively-fueled car whose main tailpipe emission is water vapor.
% http://www.forbes.com/2005/01/04/cx_dl_0104vow.html
% `` Hummer's tentative embrace of green technology ''
% ``Embracing green technology'' -- the American way.
% end hydrogen
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\item[\npageref{FisherBattery}]
{\nqs{A lithium-ion battery is 3\% lithium.}}
Source: \cite{FisherBattery}.
\item[\npageref{pEvans}]
{\nqs{Lithium specialist R.\ Keith Evans\index{Evans, R.\ Keith}
says
``concerns regarding \ind{lithium} availability \ldots\ are unfounded.''}}
-- \cite{LithiumEvans}.
% Boats, freight, planes
\item[\npageref{DutchBoats}]
{\nqs{Two Dutch-built liners known as ``The Economy Twins.''}}
% \par
\myurlb{www.ssmaritime.com/rijndam-maasdam.htm}{http://www.ssmaritime.com/rijndam-maasdam.htm}.
\par
{\nqs{QE2}}: \myurlb{www.qe2.org.uk}{http://www.qe2.org.uk/}.
\item[\npageref{pMaglev}]
{\nqs{Transrapid magnetic levitation train.}}
\url{www.transrapid.de}.
\end{notelist}
\normalsize
\ENDfullpagewidth
% Smart EV: 65 miles (105km) from 15.5 kWh ie 15 kWh per 100 km (5x better)
% Hot Zebra battery.
%% end of transport.
%\chapter{Technology for buildings}
\bset\chapter{\bcol{Smarter heating}}
\label{ch.smarth}
\label{ch.smartheating}
%\input{thermostat.tex}
%\input{construction.tex}
%\chapter{Smart heating systems}
In the last chapter, we learned that electrification
could shrink transport's energy consumption to one fifth
of its current levels; and that public transport and cycling
can be about 40 times more energy-efficient than car-driving.
How about heating?
What sort of energy-savings can technology
or lifestyle-change offer?
The power used to heat a building is given by multiplying together
three quantities:\index{building!heat consumption}
\[
\mbox{\Red{power used}}
= \frac{ \mbox{\tempcol{average temperature difference}}
\times \mbox{\leakcol{leakiness of building}}}
{ \effcol{\mbox{efficiency of heating system}} } .
\]
Let me explain this formula (which is discussed in
detail in \appref{ch.heating2}) with an example.
\marginfig{
%\begin{figure}
%\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/HouseSnowS.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/HouseSnow.jpg.eps}}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{My house.}\label{fig.MyHoA}
%% , yesterday.}
}%
% case study
My house is a three-bedroom semi-detached house built
about 1940 (\figref{fig.MyHoA}).\index{building!typical house}
The \tempcol{average temperature difference} between the inside and outside
of the house depends on the setting of the thermostat and on the weather.
If the thermostat is permanently at 20\degreesC, the average
temperature difference might be \tempcol{9\degreesC}.
The \leakcol{{\dem{leakiness}} of the building} describes how
quickly heat gets out through walls, windows, and cracks, in response
to a temperature difference. The leakiness is sometimes called
the {\dem{\ind{heat-loss coefficient}}} of the building.
It is measured in
kWh per day per degree of temperature difference.
In \chref{ch.heating2}, I calculate that the leakiness of my house in 2006
was \leakcol{7.7\,kWh/d/\ndegreeC}.
The product
\[
\mbox{\tempcol{average temperature difference}}
\times \mbox{\leakcol{leakiness of building}}
\]
is the rate at which heat flows out of the house by conduction and
ventilation. For example, if
the average
temperature difference is \tempcol{9\degreesC} then
the heat loss is
\[
\tempcol{9\degreesC} \times \leakcol{7.7\,\kWh/\d/\ndegreeC}
\simeq 70\,\kWh/\d .
\]
Finally, to calculate the power required, we divide this heat loss
by the efficiency of the heating system. In my house,
the condensing gas boiler has an efficiency of \effcol{90\%},
so we find:
\[
\mbox{\Red{power used}} =
\frac{ \tempcol{9\degreesC} \times \leakcol{7.7\,\kWh/\d/\ndegreeC}
}{ \effcol{0.9 }}
= \Red{77\,\kWh/\d}.
\]
That's bigger than the space-heating requirement
we estimated in \chref{ch.heating}.
It's bigger for two reasons: first, this formula assumes that
all the heat is supplied by the boiler, whereas in fact some heat is
supplied by incidental heat gains from occupants, gadgets, and the sun;
second, in \chref{ch.heating} we assumed that a person
kept just two rooms at 20\degreesC\ all the
time; keeping an entire house at this temperature all the time
would require more.
OK, how can we reduce the power used by heating?
Well, obviously, there are three lines of attack.
\begin{enumerate}
\item {} Reduce the \tempcol{average temperature difference}.
This can be achieved by turning thermostats down (or, if you have
friends in high places,
% it's within your power,
by changing the weather).
\item {} Reduce the {\leakcol{leakiness of the building}}.
This can be done by improving the building's insulation --
think \index{double glazing}\ind{triple glazing},\index{glazing, double}
\index{draught proofing}{draught-proofing}, and fluffy blankets in the loft
-- or, more radically,\index{loft insulation}\index{insulation}\index{fluff}
by demolishing the building and replacing it with
a better insulated building; or perhaps by living in
a building of smaller size
per person. (Leakiness tends to be bigger, the larger a building's
floor area, because the areas of external wall, window, and roof
tend to be bigger too.)
\item {} Increase the {\effcol{efficiency of the heating
system}}. You might think that \effcol{90\%} sounds hard to beat,
but actually we can do much better.
\end{enumerate}
\section{Cool technology: the thermostat}
The \ind{thermostat} (accompanied by \ind{woolly jumper}s) is hard to
beat, when it comes to value-for-money technology.
You turn it down, and your building uses less energy. Magic!
In Britain, for every
degree that you turn the thermostat down, the heat loss
decreases by about 10\%. Turning the thermostat
down from 20\degreesC\ to 15\degreesC\ would nearly halve
the heat loss.
Thanks to incidental heat gains by the building,
the savings in heating power will be even bigger than these
reductions in heat loss.
Unfortunately, however, this remarkable energy-saving
technology has side-effects.
Some humans call turning the thermostat
down a \ind{lifestyle change}, and are not happy with it.
I'll make some suggestions later about how to sidestep this
lifestyle issue.
Meanwhile, as proof that
``the most important smart component in a building with
smart heating is the occupant,''
\marginfig{\footnotesize
\begin{center}
%\rotatebox{90}{\footnotesize\sf Energy consumption (kWh/100 km)}\hspace*{8mm}%
{\epsfxsize=40mm\epsfbox{../data/HeatData.eps}}%
\end{center}
\caption[a]{Actual heat consumption in 12 identical houses
with identical heating systems.
All houses had floor area 86\,m$^2$
and were designed to have a\index{building!data}\index{data!heat consumption}
\ind{leakiness}\index{heat-loss coefficient}
of \leakcol{2.7\,kWh/d/\ndegreeC}.
% (114\,W$\!$/\ndegreeC).
% 1.3\,\Wmm/\ndegreeC
Source:
% Carbon Trust.
\cite{CarbonTrustCHP}.
% page 74
}
\label{fig.HouseData}
}%
\figref{fig.HouseData} shows data from a Carbon Trust study,
observing the heat consumption in twelve identical modern houses.
This study permits us to gawp at the family at number 1, whose
heat consumption is twice as big as that of Mr.\ and Mrs.\ Woolly at
number 12.
However, we should pay attention to the numbers: the family at
number 1 are using 43\,kWh per day. But
if this is shocking, hang on --
a moment ago, didn't I estimate that {\em{my}\/} house might use more than
that? Indeed, my average gas consumption from 1993 to 2003 was
a little more than 43\,kWh per day (\figref{fig.gas00}, \pref{fig.gas00}), and I
thought I was a frugal person!
The problem is the {\em{house}}.
All the modern houses
in the Carbon Trust study had a leakiness of
% people who live in leaky houses
\leakcol{2.7\,kWh/d/\ndegreeC}, but my house had a leakiness
of
\leakcol{7.7\,kWh/d/\ndegreeC}!
People who live in leaky houses\ldots
\section{The war on leakiness}
What can be done with leaky old houses, apart from
calling in the bulldozers?
\Figref{EdenFig} shows\nocite{EdenBending}
% \quotecite{EdenBending}
% Eden and Bending's
estimates of the space heating required
in old
detached, semi-detached, and terraced houses as progressively more effort is
put into patching them up.
\begin{figure}
\figuremargin{%
\mbox{\epsfbox{metapost/heating.1}}
}{
\caption[a]{
Estimates of the space heating required
in a range of UK houses. From
\cite{EdenBending}.}
\label{EdenFig}
}
\end{figure}
Adding loft insulation and \ind{cavity-wall insulation}
reduces heat loss in a typical old house by about 25\%.\nlabel{pEden}
Thanks to incidental heat gains, this 25\% reduction in heat
loss translates into roughly a 40\% reduction in heating consumption.
Let's put these ideas to the test.
\section{A case study}
\begin{figure}\figuremargin{
%\marginfig{
\begin{center}
\mbox{\epsfxsize=118mm\mono%
{\epsfbox{../data/mono/newgas.eps}}%
{\epsfbox{../data/newgas.eps}}%
}\\
\end{center}
}{
\caption[a]{My domestic gas consumption, each year from 1993 to 2007.
Each line shows the cumulative consumption during one year
in kWh.
The number at the end of each year is the average
rate of consumption for that year, in kWh per day.
Meter-readings are indicated by the blue points.
Evidently, the more frequently I read my meter, the less gas I use!
}
\label{fig.gas0}
}%
\end{figure}
I introduced you to my house on page \pageref{fig.gas00}. Let's pick up
the story.
% where we left it.
% My three-bedroom house.
In 2004 I had a condensing boiler
installed, replacing the old gas boiler. (Condensing boilers use
a heat-exchanger to transfer heat from the exhaust gases to incoming air.)
At the same time I removed the house's hot-water tank (so hot
water is now made only on demand),
and I put thermostats on all the bedroom radiators.
Along with the new condensing boiler came
a new heating controller that allows me to set different
target temperatures for different times of day.
With these changes, my consumption decreased from an
average of 50\,kWh/d to about 32\,kWh/d.
% I think the main reason for the improvement was the removal
% of the hot water tank. It was pretty well insulated, but
% nevertheless made the room it was in noticeably warmer,
% all year round.
This reduction from 50 to 32\,kWh/d is quite satisfying,
but it's not enough, if
the aim is to reduce one's fossil fuel footprint below
one \tonne\ of \COO\ per year.
% It's less than a 50\% reduction, and
32\,kWh/d of gas corresponds to over 2 {\tonne}s \COO\ per year.
% YARDSTICK
% 070531/
% 5358 , 9, 66,
% 67, 68
% 86 big picture
In 2007, I started paying more careful attention
to my energy meters. I had cavity-wall insulation installed
(\figref{fig.Cavit})
and improved my loft insulation.
I replaced the single-glazed back door by a double-glazed door,
and added an extra double-glazed door to the front porch (\figref{frontD}).
Most important of all,
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Cavity1.eps}}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{Cavity-wall insulation going in.}\label{fig.Cavit}
}\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=25mm\epsfbox{../../images/frontdoorOx.eps}}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{A new front door.}\label{frontD}
}I paid more attention to my thermostat settings.
This attentiveness has led to a further halving in
gas consumption.
% in 2007 compared with 2006.
% The end result:
The latest year's consumption was 13\,kWh/d!
Because this case study is such a hodge-podge of
building modifications and behaviour changes, it's
hard to be sure which changes were the most important.
According to my calculations (in \chref{ch.heating2}),
the improvements in insulation
reduced the leakiness by 25\%, from \leakcol{7.7\,kWh/d/\ndegreeC}
to \leakcol{5.8\,kWh/d/\ndegreeC}.
This is still much leakier than any modern house.
It's frustratingly difficult to reduce the leakiness
of an already-built house!
So, my main tip is cunning thermostat management.
What's a reasonable thermostat setting to aim for?
Nowadays many people seem to think that 17\degreesC\ is unbearably
cold. However, the average winter-time temperature in British houses in 1970
was 13\degreesC!\nlabel{pTemp13}
% http://www.berr.gov.uk/files/file11250.pdf para 3.11 \cite{ECUK}
% p26
A human's perception of whether they feel warm
depends on what they are doing, and what they've been doing for the
last hour or so.
My suggestion is, {\em don't think in terms of a thermostat setting.}
Rather than fixing the thermostat to a single value,
try just leaving it at a really low value most of the time (say 13 or 15\degreesC),
and turn it up temporarily whenever you feel cold.
It's like the lights in a library. If you allow yourself to ask the question
``what is the right light level in the bookshelves?''
then you'll no doubt answer ``bright enough to read the book titles,''
and you'll have bright lights on all the time. But that question presumes
that we have to fix the light level; and we don't have to.
% In wonderful Cambridge University Library
% -- a quirky
% institution where the books are sorted by size, to save shelf
% space -- the lights of every shelf-stack are individually switch-on-able
% by the reader, and they are on clockwork timers so that they switch off
% again within a few minutes.
We can fit light switches that the reader can turn on, and that
switch themselves off again after an appropriate time.
% What's remarkable about this way of handling the thermostat is the
% range of temperatures that feel satisfactory.
Similarly, thermostats don't need to be left up at 20\degreesC\ all the time.
Before leaving the topic of thermostat settings, I should
mention \index{air-conditioning}{air-condi\-tion\-ing}.
Doesn't it drive you crazy to go into a
building in summer where the thermostat of the
air-conditioning is set to 18\degreesC?
% When I suggest
% turning the winter thermostat to 18\degreesC or below,
% people think I'm some sort of freak, but i
These loony building managers are subjecting everyone
to
temperatures that in winter-time they would whinge are too cold!
In \ind{Japan}, the government's ``CoolBiz''
guidelines recommend that air-conditioning be set to 28\degreesC\
(82\,F).
\section{Better buildings}
If you get the chance to build a new building
then there are lots of ways to ensure its heating consumption is
much smaller than that of an old building.
\Figref{fig.HouseData} gave evidence that modern houses are
built to much better insulation standards than those
of the 1940s.
But the building standards in Britain could be still better,
as \chref{ch.heating2} discusses.\index{building!standards}
The three key ideas for the best results
are:
% \begin{enumerate}
% \item
(1)
have really thick insulation in
floors, walls, and roofs;
(2)
% \item
ensure the building is completely sealed and use active ventilation
to introduce fresh air and remove stale and humid air, with heat exchangers
passively recovering much of the heat from the removed air;
% \item
(3)
design the building to exploit sunshine
as much as possible.
% \end{enumerate}
\section{The energy cost of heat}
So far, this chapter has focused on
\tempcol{temperature control} and
\leakcol{leakiness}.
Now we turn to the third factor in the equation:
\[
\mbox{\Red{power used}}
= \frac{ \mbox{\tempcol{average temperature difference}}
\times \mbox{\leakcol{leakiness of building}}}
{ \effcol{\mbox{efficiency of heating system} }} .
\]
How efficiently can heat be produced?
Can we obtain heat on the cheap?
Today, building-heating in Britain is primarily delivered by
burning a fossil fuel, natural gas,
in boilers with efficiencies of 78\%--90\%. Can we get off fossil fuels at the same
time as making building-heating more efficient?
One technology that is held up as an answer
to Britain's heating problem is called ``combined heat and power'' (CHP),
or its cousin, ``micro-CHP.''
I will explain \ind{combined heat and power} now, but
I've come to the conclusion that it's a bad idea, because
there's a better technology for heating, called heat pumps,
which I'll describe in a few pages.
\marginfig{
%\begin{figure}
%\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/eggborough.eps,angle=270}}
\\
\lowres{\mbox{\epsfxsize=52mm\epsfbox{../../images/DraxS.jpg.eps}}}%
{\mbox{\epsfxsize=52mm\epsfbox{../../images/Drax.jpg.eps}}}
\\
\end{tabular}
\end{center}
%}{
\caption[a]{
Eggborough. Not a power station participating in
smart heating.
}
}
\subsection{Combined heat and power}
% \section{Combined heat and power}
The standard view
of conventional big centralised power stations
is that they are terribly inefficient, chucking heat willy-nilly up
\ind{chimney}s and \ind{cooling tower}s.
\begin{figure}
\figuremargin{
\begin{center}
{\mbox{\epsfxsize=94mm\epsfbox{crosspad/powerstation3.ps}}}
\end{center}
}{
\caption[a]{How a power station works.
There has to be a cold place to condense the steam to make the
\ind{turbine} go round. The cold place is usually a
cooling tower or \ind{river}.}\label{coldplace}
}
\end{figure}
A more sophisticated view recognizes that
to turn thermal energy into electricity, we inevitably have to dump
heat in a cold place (\figref{coldplace}). That is how \ind{heat engine}s work.
There {\em{has}\/} to be a cold place.
But surely, it's argued, we could use {\em{buildings}\/} as the
dumping place for this ``waste'' heat\index{waste heat}\index{heat!waste}
instead of
\ind{cooling tower}s or
sea water? This idea is called ``\ind{combined heat and power}''
(CHP) or cogeneration,\index{cogeneration}
and it's been widely used in \ind{continental Europe}\index{Europe!continental}
for decades -- in many cities,
%% _see _smartheating.tex for numbers from DUKEs
a big power station is integrated with
% the city's centralized
a \ind{district heating} system.
% British politicians
Proponents of the modern incarnation of combined heat and power,
``\ind{micro-CHP},'' suggest that tiny power stations
should be created within single buildings or small
collections of buildings, delivering heat and electricity to
those buildings, and exporting some electricity to the grid.
\begin{figure}[h]%[!b]
\figuremargin{
\begin{center}
{\mbox{\epsfxsize=92mm\epsfbox{crosspad/powerstation5.ps}}}
\end{center}
}{
\caption[a]{Combined heat and power.\index{combined heat and power}\index{district heating}
District heating absorbs heat that
would have been chucked up a cooling tower.}
}
\end{figure}
There's certainly some truth in the view that Britain is rather backward\nlabel{pBbackw}
when it comes to district heating and combined heat and power,
but discussion is hampered by a general lack of numbers, and by
two particular errors.
First, when comparing different ways of using fuel, the wrong measure
of ``efficiency'' is used, namely one that weights electricity as having
equal value to heat. The truth is, electricity is more valuable than heat.
Second, it's widely assumed that the ``waste'' heat in a traditional
power station could be captured for a useful purpose
{\em without impairing the power station's
electricity production}. This sadly is not true, as the numbers will show.
Delivering useful heat to a customer always reduces the electricity
produced to some degree.
% And given that electricity actually has a higher value than heat,
The true net gains from combined heat and power are
often much smaller than the \ind{hype} would lead you to believe.
% (Just 10\% or so.)
A final impediment to rational discussion of \ind{combined heat and power}
is a myth that has grown up recently, that
decentralizing a technology somehow makes it greener.
So whereas big centralized fossil fuel power stations are ``bad,''
flocks of local micro-power stations are imbued with goodness.
But if \ind{decentralization} is actually a good idea then
``small is beautiful'' should
be evident in the numbers.
Decentralization should be able to stand on its own two
feet.
% without mystical belief in the need to decentralize.
And what the numbers actually show is that {\em{centralized}\/}
electricity generation
has many benefits in both economic and energy terms.
Only in large buildings is there any benefit to local generation,
and usually that benefit is only about 10\% or 20\%.
The government has a target for growth of combined heat and power
to 10\,GW of electrical capacity by 2010, but I think that
growth of gas-powered combined heat and power
would be a mistake. Such combined heat and power is not green:
it uses fossil fuel,\index{combined heat and power!arguments against}
and it locks us into continued use of fossil fuel.
Given that heat pumps are a better technology,
I believe we should leapfrog over gas-powered combined heat and power
and go directly for heat pumps.
%\begin{figure}
%\begin{center}
%{\mbox{\epsfbox{crosspad/powerstation2.ps}}}
%\end{center}
%\caption[a]{How a power station works. Cooling tower or river.}
%\end{figure}
%\begin{figure}
%\begin{center}
%{\mbox{\epsfbox{crosspad/powerstation4.ps}}}
%\end{center}
%\caption[a]{Combined heat and power. District heating.}
%\end{figure}
\begin{figure}
\figuredangle{\small
\begin{tabular}[t]{cc}
\begin{tabular}[t]{c}
\vspace{0pt}\\
\mbox{\epsfbox{metapost/heatpump.1}}\\
air-source heat pump \\
\end{tabular}&
\begin{tabular}[t]{c}
\vspace{0pt}\\
\mbox{\epsfbox{metapost/heatpump.2}}\\
ground-source heat pump \\
\end{tabular}\\
\end{tabular}
}{
\caption[a]{Heat pumps.\index{heat pump}}\label{fig.heatpumps}
}
\end{figure}
\subsection{Heat pumps}
\label{ch.gshp}
Like district heating and combined heat and power, heat pumps
are already widely used in continental Europe, but strangely
rare in Britain.\index{Europe!continental}
% And, when you use the right measure, heat pumps are more efficient.
% Explain how heat pumps work.
Heat pumps are back-to-front refrigerators.
Feel the back of your \ind{refrigerator}: it's {\em warm}.
A refrigerator moves heat from one place (its inside) to another (its back panel).
So one way to heat a building is to turn a refrigerator inside-out --
put the {\em inside\/} of the \ind{refrigerator} in the \ind{garden},
thus cooling the
garden down; and leave the back panel of the refrigerator in your kitchen,
thus warming the house up. What isn't obvious
about this whacky idea is that
it is a really efficient way to warm your house.
For every kilowatt of power drawn from the electricity grid,
the back-to-front refrigerator can pump three kilowatts of heat from
the garden, so that a total of four kilowatts of heat gets into your house.
So heat pumps are roughly four times as efficient as a standard
electrical bar-fire.\nlabel{pGSHP}
Whereas the bar-fire's efficiency is 100\%, the
heat pump's is 400\%. The efficiency of a heat pump
is usually called its {\dem\ind{coefficient of performance}\/} or \ind{CoP}\@.
If the efficiency is 400\%,
the {{coefficient of performance}} is 4.
Heat pumps can be configured in various ways (\figref{fig.heatpumps}).
A heat pump can cool down the {\em{air}\/} in your garden using
a heat-exchanger (typically a 1-metre
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/FujitsuIn2.eps}}}%
\\
{\mbox{\epsfxsize=53mm\epsfbox{../../images/FujitsuOut.jpg.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{The inner and outer bits of an \ind{air-source heat pump}\index{heat pump!air-source}
that has
a \ind{coefficient of performance} of 4.
The inner bit is accompanied by a ball-point pen, for scale.
One of these \ind{Fujitsu} units\index{air-conditioning}
can deliver 3.6\,kW of heating when using
just 0.845\,kW of electricity. It can also run in reverse,
delivering 2.6\,kW of \ind{cooling} when using 0.655\,kW of electricity.
}\label{figASHP}
}%
tall white box, \figref{figASHP}), in which
case it's called an air-source heat pump.\index{heat pump!air-source}
Alternatively, the pump may cool down the {\em{ground}\/} using big loops
of underground plumbing (many tens of metres long),
in which case it's called a \ind{ground-source heat pump}.\index{heat pump!ground-source}
Heat can also be pumped from rivers and lakes.
Some heat pumps can pump heat in either direction.
When an air-source heat pump runs in reverse, it
uses electricity to warm up the {\em{outside}\/} air and cool down the
air {\em{inside}\/} your building. This is called air-conditioning.
% and it's exactly how many air-conditioners work.
Many air-conditioners are indeed heat-pumps working in precisely this way.
Ground-source heat pumps can also work as air-con\-di\-tion\-ers.
So a single piece of hardware can be used to provide winter heating
and summer cooling.
People sometimes say that ground-source heat pumps use ``geothermal
energy,'' but that's not the right name.
As we saw in \chref{ch.geothermal},
\ind{geothermal} energy offers only a tiny trickle of
power per unit area (about 50\,m\Wmm),
in most parts of the world; heat pumps have nothing to do
with this trickle, and they can be used both for heating
and for cooling.
% It would sound odd to
% say `I'm using geothermal energy to cool my building'.
Heat pumps simply use the ground as a place to suck heat from,
or to dump heat into. When they steadily suck heat, that heat is actually
being replenished by warmth from the sun.
There's two things left to do in this chapter.
We need to compare heat pumps with combined heat and power.
Then we need to discuss what are the limits to ground-source heat pumps.
\subsection{Heat pumps, compared with
combined heat and power
}
I used to think that \ind{combined heat and power} was a no-brainer.
``Obviously, we should use the discarded heat from power stations
to heat buildings rather than just chucking it up a cooling tower!''
However, looking carefully at the numbers describing the performance
of real CHP systems, I've come to the conclusion that there
are better ways of providing electricity and building-heating.
I'm going to build up a diagram in three steps.
The diagram shows how much electrical energy
or heat energy can be delivered from chemical energy.
The horizontal axis shows the electrical efficiency
and the vertical axis shows the heat efficiency.
\subsubsection{The standard solution with no CHP}
In the first step, we show simple power stations and heating systems
that deliver pure electricity or pure heat.
\medskip\par
\mbox{\epsfbox{metapost/heatpump.99}}
\medskip\par
Condensing boilers (the top-left dot, A) are 90\% efficient because
10\% of the heat goes up the chimney.\index{condensing boiler}
Britain's \ind{gas power station}s (the bottom-right dot, B)
are currently 49\% efficient at
turning the chemical energy of gas into electricity.
%
% spark-spread is calculated assuming a 49.13% efficiency (on a higher
% heating value (HHV) basis)."
If you want any mix of electricity and heat from natural gas,
you can obtain it by burning appropriate quantities
of gas
in the electricity power station and in the boiler.
Thus the new standard solution can deliver any
electrical efficiency and heat efficiency on the line A--B
by making the electricity and heat
using two separate pieces of hardware\@.
To give historical perspective, the diagram also shows
the old standard heating solution (an ordinary
non-condensing boiler, with an efficiency of 79\%)
and the standard way of making electricity
a few decades ago (a coal
power station with an electrical efficiency of 37\% or so).
\subsubsection{Combined heat and power}
Next we add combined heat and power systems to the diagram.
These simultaneously deliver, from chemical
energy, both electricity and heat.
\mbox{\hspace*{1cm}\epsfbox{metapost/heatpump.100}}
Each of the filled dots shows actual
average performances of CHP systems\index{data!combined heat and power}
in the UK, grouped by type. The hollow dots marked ``CT'' show the
performances of ideal CHP systems quoted by the Carbon Trust; the hollow
dots marked ``Nimbus'' are from a manufacturer's
product specifications.
% spec sheets.
The
dots marked ``ct'' are the performances quoted by the Carbon Trust for
two real systems (at Freeman Hospital and Elizabeth House).
The main thing to notice in this diagram is that the electrical
efficiencies of the CHP systems are significantly smaller
than the 49\% efficiency delivered by single-minded
electricity-only gas power stations. So the heat is not a ``free by-product.''
Increasing the heat production hurts the electricity production.
It's common practice to lump together the two numbers (the efficiency
of electricity production and heat production) into a single ``total
efficiency'' -- for example, the back pressure steam turbines
delivering 10\% electricity and 66\% heat would be called ``76\%
efficient,'' but I think this is a misleading summary of performance.
% metric. Heat is a less valuable form of energy
% than electricity, .
% CUTTABLE SENTENCE:
After all, by this measure, the 90\%-efficient condensing boiler is ``more
efficient'' than all the CHP systems!
The fact is, electrical energy is more valuable than heat.\index{combined heat and power!data}
Many of the CHP points in this
figure are superior to the ``old standard way of doing things''
(getting electricity from coal and heat from standard boilers). And
the ideal CHP systems are slightly superior to the ``new standard way
of doing things'' (getting electricity from gas and heat from
condensing boilers). But we must bear in mind that this slight
superiority comes with some drawbacks -- a CHP system delivers heat
only to the places it's connected to, whereas condensing boilers can
be planted anywhere with a gas main; and compared to the standard
way of doing things, CHP systems are not so flexible in the mix of
electricity and heat they deliver; a CHP system will work best only when
delivering a particular mix; this inflexibility leads to
inefficiencies at times when, for example, excess heat is produced;
in a typical house, much of the electricity demand
comes in relatively brief spikes, bearing little
relation to heating demand.
A final problem with some micro-CHP systems is that when they have
excess electricity to share, they may do a poor job of delivering
power to the network.
%\subsection{Heat pumps}
Finally we add in heat pumps, which use electricity from the grid
to pump ambient heat into buildings.\index{data!heat pump}
\medskip \par
\mbox{\hspace*{1cm}\epsfbox{metapost/heatpump.101}}
\medskip\par
The steep green lines show the combinations of electricity and
heat that you can obtain assuming that
heat pumps have a coefficient of performance of 3 or 4,
assuming that the extra electricity for the heat pumps
is generated by an average gas power station
or by a top-of-the-line gas power station,
and allowing for
%% \cite{Dukes07}.
8\% loss\index{transmission losses}\index{electricity grid!losses}\index{grid!losses}\index{loss!transmission losses}\index{national grid!transmission losses}\index{electricity!losses}\index{power line losses}
in the national electricity network
between the power station and the building where the heat pumps
pump heat.
The top-of-the-line gas power station's efficiency
is 53\%, assuming it's running optimally.
% http://www.e8.org/index.jsp?numPage=138
% 53\% (based on Higher Heating Value), the highest level in the world.
%%
% Yes the losses are 1.5% in HV (grid) transmission and c. 6% in LV
% (Distribution network) transmission. The latter varies widely by area
% ("GSP Group") depending on urbanity and hence extent of undergrounding
(I imagine the Carbon Trust and Nimbus made a similar assumption
when providing the numbers used in this diagram for CHP systems.)
In the future, heat pumps will probably get even better than
I assumed here.
In \ind{Japan}, thanks to strong legislation favouring
efficiency improvements, heat pumps are now available
with a coefficient of performance of 4.9.
% bigger than 4 -- the
% ``\ind{EcoCute}'' has a coefficient of performance of
% 4.9,
Notice that heat pumps offer a system that can be ``better than
100\%-efficient.'' For example the ``best gas'' power station, feeding
electricity to heat
pumps can deliver a combination of 30\%-efficient electricity and
80\%-efficient heat, a ``total efficiency'' of 110\%. No plain CHP system
% without heat pumps
could ever match this performance.
Let me spell this out.
Heat pumps are superior in efficiency to \ind{condensing boiler}s,
even if the heat pumps are powered by electricity
from a power station burning natural gas.
If you want to heat lots of buildings using natural gas, you could
install condensing boilers, which are ``90\% efficient,'' or you could
send the same gas to a new gas power station making electricity and
install electricity-powered heat pumps in all the
buildings; the second solution's efficiency would be somewhere
between 140\% and 185\%.
It's not necessary to dig big holes in the garden
and install \ind{under-floor heating}\index{heating!under-floor}
to get the benefits of\index{heat pump!air source}
heat pumps; the best \ind{air-source heat pump}s (which require just a small
external box, like an \index{air-conditioning}{air-conditioner}'s) can deliver hot water
to normal radiators with a coefficient of performance above 3.
% emmatingley
% http://www.bsee.co.uk/news/fullstory.php/aid/2460/The_value-engineering_replacement_route_to_low-carbon_heating_and_cooling.html
% these guys assume GSHP can do 4.75
% 'GSHP would appear to be the most carbon-efficient technology'
% Reg Brown is head of the energy and environment section at BSRIA, Old Bracknell Lane West, Bracknell, Berks RG12 7AH.
% [energy@bsria.co.uk]
The air-source heat pump in \figref{figASHP} (\pref{figASHP}) directly delivers
warm air to an office.
I thus conclude that combined heat and power, even though it sounds a
good idea, is probably not the best way to heat buildings
and make electricity
using natural gas, assuming that air-source or
ground-source heat pumps can be installed in the buildings. The
heat-pump solution has further advantages that should be emphasized:
heat pumps can be located in any buildings where there is an
electricity supply; they can be driven by any electricity source, so
they keep on working when the gas runs out or the gas price goes
through the roof; and
heat pumps are flexible: they can be turned on and
off to suit the demand of the building occupants.
I emphasize that this critical comparison does not mean that CHP is always
a bad idea. What I'm comparing here
are methods for heating ordinary
buildings, which requires only very low-grade heat.
CHP can also be used to deliver higher-grade heat to
industrial users (at 200\degreesC, for example). In such
industrial settings,
heat pumps are unlikely to compete so well because their coefficient of
performance would be lower.
%See also the chapter Heating II.
% US translation: CHP = Cogeneration.
\subsection{Limits to growth (of heat pumps)}
Because the temperature of the ground, a few metres down,
stays sluggishly close to 11\degreesC, whether it's summer or
winter, the ground is theoretically a better place for a
heat pump to grab its heat than the air, which in midwinter
may be 10 or 15\degreesC\ colder than the ground. So heat-pump advisors
encourage the choice of ground-source over air-source
heat pumps, where possible.\index{ground-source heat pump}\index{heat pump!ground-source}
(Heat pumps work less efficiently when there's
a big temperature difference between the inside and outside.)
However, the ground is not a limitless source of heat. The heat has to come
from somewhere, and ground is not a very good thermal conductor. If
we suck heat too fast from the ground, the ground will become as cold
as ice, and the advantage of the ground-source heat pump will be
diminished.
In Britain,
the main purpose of heat pumps would be to get heat into
buildings in the winter. The ultimate source of this heat is the
sun, which replenishes heat in the ground by direct radiation
and by conduction through the air. The rate at which heat is sucked
from the ground must satisfy two constraints:
it must not cause the ground's temperature to drop too low during
the winter; and the heat sucked in the winter must be replenished
somehow during the summer. If there's any risk that the {\em{natural}\/}
trickling
of heat in the summer won't make up for the heat removed
in the winter, then the replenishment must be driven {\em{actively}\/} --
for example by running the system in reverse in summer,
putting heat down into the ground (and thus providing air-conditioning
up top).
Let's put some numbers into this discussion.
How big a piece of ground does a ground-source heat pump need?
% And is it feasible to store up a load of heat over the summer
% and suck it back again in the winter?
%
\begin{figure}
\figuredangle{
%\mbox{\epsfbox{metapost/heatpump.4}}
\mbox{\epsfbox{metapost/heatpump.3}}
}{
\caption[a]{
How close together can ground-source heat pumps be packed?
}
}
\end{figure}
%
Assume that we have a neighbourhood
% town or city,
with quite
a high population density -- say
6200 people per km$^2$
\margintab{
\begin{center}\small
\begin{tabular}{p{30mm}r}
\toprule
\multicolumn{2}{r}{area per person (m$^2$)} \\ \midrule
Bangalore & 37 \\%&26\,719\\%/km$^2$\\
Manhattan & 39 \\%&25\,849\\%/km$^2$\\
Paris & 40 \\%&24\,775\\%/km$^2$\\
Chelsea & 66 \\%&15\,177\\%/km$^2$\\
Tokyo & 72 \\%&13\,800\\%/km$^2$\\
Moscow & 97 \\%&10\,275\\%/km$^2$\\
Taipei & 104 \\%&9626\\%/km$^2$\\
The Hague & 152 \\%&6600\\%/km$^2$\\
San Francisco& 156 \\%&6423\\%/km$^2$\\
Singapore & 156 \\%&6411\\%/km$^2$\\
Cambridge MA & 164 \\%& 6086\\%/km$^2$\\
Sydney & 174 \\%&5736\\%/km$^2$\\
Portsmouth & 213 \\%&4689\\%/km$^2$\\
\bottomrule
\end{tabular}
\end{center}
\caption[a]{Some urban areas per person.}% of cities}
\label{tab.urbanArea}\index{data!urban population density}\index{population density!urban}
}%
(160\,m$^2$ per person), the density of a typical British suburb.
Can {\em{everyone}\/} use ground-source heat pumps,
without using active summer replenishment?
A calculation in \chref{pHP1} (\pref{pHP1}) gives a tentative answer
of {\em{no}}: if we wanted everyone in the neighbourhood
to be able to pull from the ground a heat flow of about 48\,kWh/d
per person
(my estimate of our
typical winter heat demand), we'd end up freezing the ground in the
winter. Avoiding unreasonable cooling of the ground
requires that the sucking rate be less than
12\,kWh/d per person. So if we switch to ground-source heat pumps,
we should plan to include substantial summer heat-dumping\label{pSummerReplen} in the design, so as to
refill the ground with heat for use in the winter. This summer heat-dumping could
use heat from air-conditioning, or heat from roof-mounted
solar water-heating panels. (Summer solar heat is
stored in the ground for subsequent use in winter by
Drake Landing Solar Community in Canada [\myurlb{www.dlsc.ca}{http://www.dlsc.ca/}].)
% ) in Okotoks Alberta (just south of Calgary). Thus getting 90% of all heat.
Alternatively, we should expect to need to use some
air-source heat pumps too, and then we'll be able to get all the heat we want --
as long as we have the electricity to pump it.
In the \UK, air temperatures don't go very far below freezing, so
concerns about poor winter-time\index{winter!heat pumps}\index{heat pump!winter}
% \COP\
performance
of air-source pumps, which
might apply in North America and Scandinavia,
probably do not apply in Britain.
My conclusion: can we reduce the energy we consume for heating?
Yes.
Can we get off fossil fuels at the same time?
Yes.
Not forgetting the low-hanging fruit --
building-insulation and thermostat shenanigans --
we should replace all our fossil-fuel heaters with electric-powered
heat pumps; we can reduce the energy required
to 25\% of today's levels. Of course this plan for electrification
would require more electricity. But even if the
extra electricity came from gas-fired power stations,
that would still be a much better way to get heating than
what we do today, simply setting fire to the gas.
Heat pumps are future-proof, allowing us to heat buildings
efficiently with electricity from any source.
Nay-sayers object that the \ind{coefficient of performance} of
air-source heat pumps is lousy -- just 2 or 3.
But their information is out of date. If we are
careful to buy top-of-the-line heat pumps, we can do much better.
The \index{Japan!efficiency legislation}Japanese
government\index{efficiency legislation} legislated a decade-long efficiency
drive that has greatly improved the performance of air-conditioners;
thanks to this drive, there are now air-source heat pumps with a coefficient
of performance of 4.9;
these heat pumps can make hot water as well as hot air.\nlabel{pJapH}
Another objection to heat pumps is ``oh, we can't approve
of people
fitting efficient air-source heaters, because they might use
them for air-conditioning in the summer.''
Come on -- I hate gratuitous air-conditioning as much
as anyone, but
these heat pumps are four times more efficient than any other
winter heating method! Show me a better choice.
Wood pellets? Sure, a few wood-scavengers can burn wood. But there is
not enough wood for everyone to do so.
For forest-dwellers, there's wood. For everyone else, there's
heat pumps.
\amarginfignocaption{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=53mm\epsfbox{../../images/BWPowerS.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/BWPower.jpg.eps}} \\
\end{tabular}\label{Claire5}
\end{center}
%\caption[a]{ }
}
% http://www.ornl.gov/sci/engineering_science_technology/eere_research_reports/electrically_driven_heat_pumps/advanced_cycle_development/dynamic_losses/ornl_con_150/ornl_con_150.pdf
% report on performance of an air source heat pump. 1981-83
%
% http://cetc-varennes.nrcan.gc.ca/en/b_b/ac_irc/r_ss/vdmt.html
% http://www.eia.doe.gov/cneaf/solar.renewables/rea_issues/html/geotsurv.html
%
% gir72.pdf is about a domestic heat pump (4kW) in the UK. its average CoP was 3.16
% output temperature 45\degreesC. Booster direct electric heaters
% also included (4kW). (because a higher 6kW heat pump would
% have required three-phase supply.) IVT Greenline 4 from Sweden.
% 200m ground loop, buried 1m deep. domestic water has backup
% 3kW electric heater. Underfloor space heating.
% One year's supplied space-heat 13\,985kWh, hot water 1895\,kWh,
% total of 15\,880\,kWh using electricity 5025\,kWh.
% Immersion heater had to be used for 1530 units of water heating
% ie the heat pump supplied only 55\% of the hot water heat
% Performance would have been better if the distribution pump (87W)
% had not been running nonstop all year. Were this fixed, it's predicted
% the CoP would be 3.43 instead.
% p8 has a graph of output versus temperature difference
% heat collection rate about 19-27W per metre length
% of collector.
% in winter typical differential is 5C: from ground: 2-3C,
% to the ground: -1 or -2 C.
% in summer typical temperatures are 11C and 6C.
% http://www.heatpumpnet.org.uk/files/gir72.pdf
%
% http://www.poolpump.org/pool-heat-pumps.html
% http://www.soundgt.com/pumps.htm
% http://www.geothermalint.co.uk/commercial/designandinstallation.html
%
% http://www.geoenergyusa.com/technology.htm
% is a summary doc - it says that air source heatpumps do 2-3 COP,
% I expect in the UK the figure would be better
% and _their_ GSHP does COP of more than 4.0. They say
% below-freezing air temperatures are problematic for air/air heat pumps
% they say the ground temperature is 44-55 fahrenheit
% (6.7-12.8 C)
% and they deliver heat in the house at 100F. 37.8C
% can't trust them though. they don't know what a kWh is.
% http://www.ornl.gov/sci/engineering_science_technology/eere_research_reports/other_publications/iea_annex_1_vol_1/iea_annex_1_vol_1.pdf
% IEA Common Study on Advanced Heat Pump Systems
% 1981
% canada mean winter ground tempeature 8C. mean air temperature -10.4C.
% typical COP of ground-water heat pump
% in canada 3 to 3.5 versus 1.7 if use air
%
% to get heat to transfer from the 47F ground water in practice
% use 30F water; and the radiators will be about 30F warmer than
% room temperature (ie they will be at 100F).
% rankine - like stirling, but with a phase change?
%% wikipedia says Stirling {\heatpump}s also often have a higher coefficient of performance than conventional {\heatpump}s.
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pEden}]
{\nqs{Loft and cavity insulation
reduces heat loss in a typical old house by about a quarter.
}} \cite{EdenBending}.
\item[\npageref{pTemp13}]
{\nqs{ The average internal temperature in British houses in 1970
was 13\degreesC!}}
% \myurl{ http://www.berr.gov.uk/files/file11250.pdf para 3.11
Source: \citet[para 3.11]{ECUK}
% p26 THIS INFO IS REPEATED IN HEATING2.tex (cut from there?) DONE
\item[\npageref{pBbackw}]
{\nqs{Britain is rather backward
when it comes to district heating and combined heat and power}.}
The rejected heat from UK power stations could meet the heating needs of the
entire country \citep{WoodB}.
In Denmark in 1985, district heating systems supplied
42\% of space heating, with heat being transmitted 20\,km or
more in hot pressurized water.
%
In West Germany in 1985, 4 million dwellings received 7\,kW per dwelling
from district heating.
% (I think that's capacity.)
% Total heat supplied averages 42\,GJ/y.
Two thirds of the heat supplied
was from power stations.
% These German district heating schemes were profitable.
% , having a sale:purchase ratio of 3.5:1.
%
In Vasteras, Sweden in 1985,
98\% of the city's heat was supplied from power stations.
\item[\pageref{pGSHP}]
{\nqs{Heat pumps are roughly four times as efficient as a standard
electrical bar-fire.}}
See \myurlb{www.gshp.org.uk}{http://www.gshp.org.uk/}.
% \tinyurl{6anyh8}{http://www.gshp.org.uk/gshp.htm}
% http://www.nef.org.uk/gshp/gshp.htm}.
Some heat pumps available in the UK
already have a coefficient of peformance bigger than 4.0
\tinyurl{yok2nw}{http://www.eca.gov.uk/etl/find/_P_Heatpumps/ detail.htm?ProductID=9868&
FromTechnology=
S_WaterSourcePackaged}.
Indeed there is a government subsidy
for water-source heat pumps
that applies only to pumps with a coefficient of peformance better than 4.4
\tinyurl{2dtx8z}{http://www.eca.gov.uk/NR/rdonlyres/6754FE19-C697-49DA-B482-DA9426611ACF/0/ETCL2007.pdf}.
% Residential ground-source heatpumps are available with a coefficient of
% performance of 5.7 for cooling and 4.3 for heating.
Commercial ground-source {\heatpump}s are available with a coefficient of
performance of 5.4 for cooling and 4.9 for heating
\tinyurl{2fd8ar}{http://www.geothermalint.co.uk/commercial/hydronicheatpumpranges.html}.
\item[\npageref{pJapH}]
{\nqs{Air-source heat pumps with a coefficient
of performance of 4.9\ldots}}
According to
\citet{JapanHeatPump}, heat pumps with a \ind{coefficient of performance}
of 6.6 have been available in Japan since 2006.
The performance of heat pumps in Japan
improved from 3 to 6 within a decade thanks to government
regulations.
% The key change in technology was the
% advent of INVERTER
% which changes the RPM of motor.
% Heat pump performance improved 40% 1995-2005.
% Top Runner regulations started 1999
\citet{JapanHeatPump}
describe an air-source-heat-pump
water-heater called \ind{Eco Cute}
with a \ind{coefficient of performance}
of 4.9. The \ind{Eco Cute} came on the market in 2001.
% It uses CO2 as refrigerant.
\myurlb{www.ecosystem-japan.com}{http://www.ecosystem-japan.com/}.
\item[Further reading on heat pumps:]
% See also:
European Heat Pump Network
\par
\myurlb{ehpn.fiz-karlsruhe.de/en/}{http://ehpn.fiz-karlsruhe.de/en/},
\par
% Further reading on heat pumps:
\myurlb{www.kensaengineering.com}{http://www.kensaengineering.com/},
\par
% Kensa heat pumps install GSHP in UK homes.
% air source
\myurlb{www.heatking.co.uk}{http://www.heatking.co.uk/},
\par
% More {Heat pump pictures and facts}
% from
\myurlb{www.iceenergy.co.uk}{http://www.iceenergy.co.uk/}.
%% original in refs/LondonPosters.pdf
\marginfig{
\begin{center}
{\mbox{\epsfxsize=53mm\epsfbox{../../refs/TurnDownJ.eps}}}
\end{center}
%}{
\caption[a]{
Advertisement from the \ind{Mayor of London}'s
``\ind{DIY planet repairs}'' campaign of 2007.\index{advertisement}
The text reads ``{\bf\index{turn down}{Turn down}}.\index{Mayor of London}\index{London}
If every London household turned down their \ind{thermostat} by one
degree, we could save 837\,000 {\tonne}s of \COO\ and
\pounds110m per year.''
% cf charger 31,000 {\tonne}s of \COO\ and \pounds7.75m per year'.
[{\myurlb{london.gov.uk/diy}{http://london.gov.uk/diy}}]
Expressed in savings per person, that's 0.12\,t\,\COO\ per year
per person. That's about 1\% of one person's total (11\,t), so this {\em{is}\/}
good advice. Well done, \ind{Ken}!\index{Livingstone, Ken}% Ken!
}
}
% see _smartheating
% http://markbrinkley.blogspot.com/2006/01/just-how-good-are-heat-pumps.html
% we suspect iceenergy of exagg.
% \item[] mechanical ventilation with heat recovery
%\item[] \ind{Passivhaus} standard (15\,kWh/m$^2$/y for heating, and
% 120\,kWh/m$^2$/y for all energy use).
\end{notelist}
\normalsize
\bset\chapter{\bcol{Efficient electricity use}}
\label{ch.smarte}
\label{ch.vampire}
Can we cut electricity use?
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\epsfxsize=23mm\epsfbox{../../images/IKEAcrap2.eps}} \\
\end{tabular}
\end{center}
\caption[a]{An awful AC lamp-adaptor from
\ind{IKEA} -- the adaptor uses nearly 10\,W even when the lamp is
switched off!
}\label{IKEAcrap}
}%
Yes, switching off gadgets when they're not in use
is an easy way to make a difference.
Energy-efficient light bulbs will save you electricity too.
We already examined gadgets in \chref{ch.gadget}.
Some gadgets are unimportant, but some are astonishing
guzzlers. The laser-printer in my office, sitting there doing nothing,
is slurping 17\,W -- nearly 0.5\,kWh per day!
A friend bought a lamp from IKEA\@.
Its awful adaptor
(\figref{IKEAcrap})
guzzles 10\,W (0.25\,kWh per day) whether or not the
lamp is on.
If you add up a few stereos, DVD players, cable modems,
and wireless devices, you may even find that half of your
home electricity consumption can be saved.
According to the International Energy Agency,
\ind{standby power}\index{power!standby} consumption accounts for roughly
% in all IEA countries the answer is 10%
8\% of residential electricity demand.\nlabel{pBlip}
In the UK and France, the average standby power is about
% 32W, 29W (which is actually 8% of residential elec
0.75\,kWh/d per household.
The problem
isn't standby itself
-- it's the shoddy way in which
standby is implemented. It's perfectly possible to
make standby systems that draw less than 0.01\,W; but manufacturers,
saving themselves a penny in the manufacturing costs,
are saddling the consumer with an annual cost of pounds.
\begin{figure}[bhtp]
\figuremargin{
\begin{tabular}{@{}c}
% {\epsfxsize=110mm\epsfbox{../data/elecDet.eps}}%
%% gnuplot < elec.gnud
\\
{\epsfxsize=100mm\epsfbox{../data/vampD.eps}}%
\end{tabular}
}{
\caption[a]{Efficiency in the offing.
I measured the electricity savings from switching off vampires
% The top graph shows the raw meter readings.
% The bottom graph shows the power consumption,
% deduced from the meter readings.
during a week when I was away at work most of each day,\index{vampire power}
so both days and nights were almost devoid of useful
activity, except for the fridge. The brief little blips of
consumption are caused by the microwave, toaster,
washing machine, or vacuum cleaner.
% This experiment was
% concerned with the non-stop power consumption.
On the Tuesday I switched off most of my vampires:
two stereos, a DVD player, a cable modem, a wireless router,
and an answering machine.
The red line shows the trend of ``nobody-at-home''
consumption before, and the green line shows the ``nobody-at-home''
consumption after this change.
Consumption fell by 45\,W, or 1.1\,kWh per day.
}\label{fig.vampE}
}
\end{figure}
% elec.gnud
% Of course, this is only my total domestic consumption,
% not my
\section{A vampire-killing experiment}
\Figref{fig.vampE} shows
an experiment I did at home.
First, for two days, I measured the power consumption when
I was out or asleep.
Then, switching off all the gadgets
that I normally left on, I measured again for three
more days. I found that the
power saved was 45\,W -- which is worth \pounds45 per year
if electricity costs 11p per unit.
Since I started paying attention to my meter readings,
my total electricity
consumption has halved (\figref{fig.vampBigPic}). I've
cemented this saving in place by
making a habit of reading my meters every week, so as to check
that the electricity-sucking vampires have been banished.
If this magic trick could be repeated in all homes and
all workplaces, we could obviously make substantial savings.
So a bunch of us in Cambridge are putting together a website
devoted to making regular meter-reading fun and informative.
The website, \myurl{ReadYourMeter.org}, aims to help people carry out
similar experiments to mine, make sense of the resulting
numbers, and get a warm fuzzy feeling from using less.
I do hope that this sort of smart-metering activity
will make a difference. In
the future cartoon-Britain of 2050, however,
I've assumed that all such electricity savings are
cancelled out by the miracle of growth.
Growth is one of the tenets of our society: people
are going to be wealthier, and thus able to play with more
gadgets. The demand for ever-more-superlative computer
games forces computers' power consumption to increase.
Last decade's computers used to be thought pretty neat, but now
they are found useless, and must be replaced by faster, hotter
\marginfig{
\mbox{\epsfxsize=50mm%
\raisebox{2.6mm}{\epsfbox{../data/SmugElec.eps}}%
%% gnuplot < newelec.gnu2ps
}
\caption[a]{My cumulative
domestic electricity consumption, in kWh, each year from 1993 to 2008.
The grey lines show years from 1993 to 2003.
(I haven't labelled these with their years, to avoid clutter.)
The coloured lines show
the years 2004 onwards.
The scale on the right shows the average
rate of energy consumption, in kWh per day.
The vampire experiment took place on 2nd October 2007.
The combination of vampire-banishment with energy-saving-lightbulb
installation reduced my electricity consumption from 4\,kWh/d to 2\,kWh/d.
}\label{fig.vampBigPic}
}%
machines.
% despised for their inability
% to deliver multiple channels of digital television
% guzzle more than last decade's computers of last decade
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pBlip}]
{\nqs{
Standby power consumption accounts for roughly
8\% of residential electricity.}}
Source:
% p86
\cite{BlipNight}. \par
For further reading on standby-power policies, see:\par
\myurlb{www.iea.org/textbase/subjectqueries/standby.asp}{http://www.iea.org/textbase/subjectqueries/standby.asp}.
\end{notelist}
\normalsize
\gset\chapter{\gcol{Sustainable fossil fuels?}}
\label{ch.sff}
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=50mm\epsfbox{../../images/LordHinton_iIanBoyle.jpg.eps}} \\
\mbox{\epsfxsize=50mm\epsfbox{../../images/Kingsnorth_IanBoyle.jpg.eps}} \\
\end{tabular}
\end{center}
\caption[a]{%
Coal being delivered to
Kingsnorth power station (capacity 1940\,MW) in 2005.
\ianboyles. }\label{fig.coalDeliv}
}
% pr 1600./6 * 8000 / 1000 / 365
% 5.84474885844749
\myquote{It is an inescapable reality that fossil fuels will continue
to be an important part of the energy mix for decades to come.
}{UK government spokesperson, April 2008}
% source
% http://www.guardian.co.uk/environment/2008/apr/01/carbonemissions.biofuels
\myquote%
{Our present happy progressive condition is a
thing of limited duration.
}{William Stanley Jevons, 1865\index{Jevons, William Stanley}}
%\end{quote}
\noindent
% We've estimated in part I the maximum conceivable
% power production from all the traditional renewables in the UK.
We explored in the last three chapters
the main technologies and lifestyle changes
for reducing power consumption. We found that we could halve the power consumption
of transport (and de-fossilize it) by switching to electric vehicles.
We found that we could shrink the power consumption of
heating even more (and de-fossilize it) by insulating all buildings better and using electric
heat pumps instead of fossil fuels.
So yes, we can reduce consumption. But still, matching even this
reduced consumption with power from Britain's own renewables
looks very challenging (\figref{fig.halftime3}, \pref{fig.halftime3}).
It's time to discuss non-renewable options for power production.%
Take the known reserves of fossil fuels, which are overwhelmingly
coal: 1600\,Gt of coal.
Share them equally between six billion people,
and burn them ``sustainably.'' What do we mean if we talk
about using up a finite resource ``sustainably''? Here's the arbitrary
definition I'll use: the burn-rate is ``sustainable'' if the
resources would last
\timecolor{1000 years}.\nlabel{pS1000}\index{definition!sustainable}\index{sustainable!definition}
A \tonne\ of coal delivers 8000\,kWh
of chemical energy,\nlabel{pcoal} so
1600\,Gt of coal shared between 6\,billion people over 1000 years
% is 270\,\tonnes\ per person; and a \tonne\ of coal delivers 8000\,kWh
% of a chemical energy.
% So the power delivered would be
works out to a power of
{\OliveGreen{6\,kWh per day per person}}.%
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{cc}
% {\sc Consumption}& {\sc Production}\\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.246}} }\\
%\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.342}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{``Sustainable fossil fuels.''
}
}
% \end{figure}
% Let's assume that one quarter of this goes to seqn. costs
% We'll discuss in part \ref{partCarbon} whether burning
% fossil fuels at this small rate would cause other problems.
A standard coal power station would turn this chemical power into electricity
with an efficiency of about 37\% -- that means about
\OliveGreen{2.2\,\kWhe\ per
day per person}.\index{coal power station}
If we care about the climate, however, then presumably
we would not use a standard power station. Rather, we would
go for ``clean coal,'' also known as ``coal with carbon capture and
storage'' -- an as-yet scarcely-implemented technology
that sucks most of the
\ind{carbon dioxide}\index{carbon capture and storage}\index{sequestration}\index{carbon sequestration}\index{CCS}
out of the \ind{chimney}-flue gases
and then shoves it down a hole in the ground.\nlabel{pCCS}
Cleaning up power station emissions in this way
has a significant energy cost -- it would reduce the delivered
electricity by about 25\%. So a ``sustainable'' use of
known coal reserves would deliver only about
{\OliveGreen{1.6\,\kWheb\ per
day per person}}.
We can compare this ``sustainable'' coal-burning rate -- 1.6\,Gt per year --
with the current global rate of coal consumption:
% 2006 figure: 3.08 Gtoe/y to convert to Gt coal, mult by (7.33 / 3.6)
% 6.3\,Gt per year, in 2006.
% http://www.worldcoal.org/pages/content/index.asp?PageID=104
% 5\,Gt per year.
% http://www.eia.doe.gov/emeu/aer/txt/ptb1114.html 2004 figure in short tons
6.3\,Gt per year, and rising.
%\section
{What about the UK alone?}
Britain
% used to have outstanding coal reserves. Now it's
is estimated to have 7\,Gt
% billion \tonnes\
of coal left.\nlabel{ukcoal}
% in the energy_review_2006.07.pdf it says
% 865 M t plus 400 Mt.
% see _sus...
%%
OK, if we share
7\,Gt
% 7 billion \tonnes\
between 60 million people,
we get 100 \tonnes\ per person. If we want a 1000-year solution,
% that's 0.1 tonnes per year. Each tonne is 8000\,kWh, so 800\,kWh per year,
% which is about
this corresponds to \OliveGreen{2.5\,kWh per day per person}.
% 2.55
In a power station performing carbon capture and storage, this
sustainable approach to UK coal\index{sustainable coal}
would yield\index{coal!UK}
\OliveGreen{0.7\,\kWhe\ per day per person}.
Our conclusion is clear:
% already cited at end
% \tinyurl{yhxf8b}{http://www.worldenergy.org/wec-geis/publications/reports/ser/coal/coal.asp}
% http://www.worldenergy.org/wec-geis/publications/reports/ser/coal/coal.asp
% Coal: proved recoverable reserves at end-1999.
% UK: 1500 million tonnes.
% (Europe total 300\,000 million tonnes; world 980\,000 million tonnes.)
% In 1952 according to an oil drum poster the
% reserves were 45.7 billion tons
% http://www.theoildrum.com/node/2738
\begin{oldcenter}
{\em Clean coal is only a stop-gap.}
\end{oldcenter}
If we do develop ``clean coal'' technology in order to reduce
greenhouse gas emissions,
we must be careful, while patting ourselves on the back, to
do the accounting honestly. The coal-burning process releases
greenhouse gases not only at the power station but also at the coal mine.
Coal-mining\index{mining!coal}\index{coal mining} tends to release methane,
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm\epsfbox{../../images/OpenCastCoal.eps}} \\
\end{tabular}
\end{center}
\caption[a]{%
A caterpillar grazing on old leaves.\index{coal mining}
Photo by Peter Gunn. }\label{fig.coalMine}
}%
%
\ind{carbon monoxide}, and \ind{carbon dioxide},\nlabel{CoalLeak}
both directly from the \ind{coal} seams as they are exposed,
and subsequently from discarded shales and mudstones;
% which contain carbon, some of which oxidizes when exposed to air;
for an ordinary coal power station,
these coal-mine emissions bump up the greenhouse gas footprint by about 2\%,
so for a ``clean'' coal power station, these emissions may have some impact on the
accounts.
There's a similar accounting problem with natural gas:
if, say, 5\% of the natural gas leaks\index{natural gas!leaks} out along the
journey from hole in the ground to power station, then
this accidental \ind{methane pollution} is equivalent (in greenhouse
effect) to a 40\%
boost in the carbon dioxide released at the power station.\label{pMethane88}
\section{New coal technologies}
Stanford-based company
\myurlb{directcarbon.com}{http://www.directcarbon.com/}
are\index{direct carbon fuel cell}\index{carbon fuel cell}
developing the {\dem{Direct Carbon Fuel Cell}},\index{fuel cell!direct carbon}
which converts fuel and air directly to electricity and \COO,
without involving any water or steam turbines.
They claim that this way of generating electricity
from coal is twice as efficient as the standard power station.
%%%%%%%%%%%%
\section{When's the end of business as usual?}
The economist Jevons\index{Jevons, William Stanley}
did a simple calculation in 1865.
People were discussing how long British coal would last.
They tended to answer this question
by dividing the estimated coal remaining by the
rate of coal consumption, getting answers like ``1000 years.''
But, Jevons said, consumption is {\em{not}\/} constant.
It's been doubling every 20 years, and
% under the banner
``progress'' would have it continue to do so.
So ``reserves divided by consumption-rate'' gives the wrong answer.
Instead, Jevons extrapolated the exponentially-growing
consumption, calculating the time by which the total amount
consumed would exceed the estimated reserves.
This was a much shorter time.
Jevons was not assuming that consumption would actually
continue to grow at the same rate; rather he was making the point
that growth was not sustainable. His calculation
estimated for his British readership the inevitable limits
to their growth, and the short time remaining before those limits would
become evident.
% happy and benevolent way of dealing with the world.
Jevons made the bold prediction
that the end of British ``progress'' would come within 100 years
of 1865.
Jevons was right.
% Jevons's Britain ruled the world.
% Now Britain is a second-rate nation.
British coal production peaked in 1910, and by 1965 Britain was no longer
a world superpower.
% http://www.worldcoal.org/pages/content/index.asp?PageID=188
% 2006e 5370Mt hard coal plus 2006e 914Mt brown coal
Let's repeat his calculation for the world as a whole.
% SaudiOil.txt index 2
% 2006 3.08*(7.33 / 3.6)
In 2006, the coal consumption rate was 6.3\,Gt per year.
Comparing this with reserves of 1600\,Gt of coal,
people often say ``there's \timecolor{250 years} of coal left.''
% 254
But if we assume ``business as usual'' implies a
growing consumption, we get a different answer.
If the growth rate of coal consumption were to continue
at 2\% per year (which gives
a reasonable fit to the data from 1930 to 2000),
then all the coal would be gone in 2096.
If the growth rate is 3.4\% per year
(the growth rate over the last decade),
% log( 5370 / 3734 ) / 10.0 using hard coal stats production
the end of business-as-usual is coming before 2072.
% If the growth rate is 3\%, the end of `progress' is guaranteed to be before 2077.
% see data/jevons.m
Not \timecolor{250 years}, but \timecolor{60}!
% If the growth rate is 5\% (the world growth rate today),
% the end of business as usual is guaranteed to be before 2058.
% 52 years to go.
% [The actual growth of coal consumption
% from 2005 to 2006 was 8.8\%.]
If Jevons were here today, I
%With a blinkered nuclear-free Jevons view of the situation, I
am sure he would firmly predict that unless we steer ourselves
on a course different from business as usual,
there will, by 2050 or 2060, be an end to our
happy progressive condition.
% world energy crisis about 2050
% -- well before any global climate catastrophe.
%\begin{figure}[hbtp]
%\fullwidthfigure{
%% marginpar[b]{
\beginfullpagewidth
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=175mm\epsfbox{../../images/DraxLandscape.eps}} \\
% ../../images/SustainableFossilFuels.jpg.eps}} \\
% REPLACE BY MY PICTURE OF EGGBOROUGH done.
\end{tabular}\par
\end{center}
% \, \par
%\caption[a]{ Sustainable Fossil Fuels }
%\label{pSFF}
%}
%\end{figure}
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pS1000}]
{\nqs{1000 years -- my arbitrary definition of ``sustainable.''}}
As precedent for this sort of choice,
% Hansen et al (2007)
\citet{Hansen2007} equate ``more than 500 years'' with ``forever.''
%% CUTTABLE
\item[\npageref{pcoal}]
{\nqs{1 ton of coal equivalent = 29.3\,GJ = 8000\,kWh}} of chemical energy.
% not electricity.
This figure does not include the energy costs of mining,
transport, and carbon sequestration.
\item[\npageref{pCCS}]
{\nqs{Carbon capture and storage}} (CCS).
There are several CCS technologies. Sucking the \COO\ from the flue gases is one;
others gasify the coal and separate the \COO\ before combustion.
See \cite{IPCC2005:capture}.
% 30 MW tiny
The first prototype coal plant with CCS was opened on 9th September 2008
by the Swedish company Vattenfall
\tinyurl{5kpjk8}{http://blogs.reuters.com/environment/2008/09/09/a-silver-bullet-or-just-greenwash/}.
\item[\npageref{ukcoal}]
{\nqs{UK coal}}.
In December 2005, the reserves and resources
at {\em{existing mines}\/} were estimated
to be 350 million \tonnes.
In November 2005, potential opencast reserves were estimated to be
620 million \tonnes;
%
% Wed 1/8/07
% http://news.bbc.co.uk/1/low/wales/6925416.stm
% 20 million tonnes expected from a single mine reopened in wales
and the underground coal gasification potential was estimated to be
at least 7 billion \tonnes.
\tinyurl{yebuk8}{http://www.dti.gov.uk/energy/sources/coal/index.html}
% density of methane:
\item[\npageref{CoalLeak}]
{\nqs{Coal-mining tends to release greenhouse gases}}.
For information about methane release from coal-mining see
% \myurl{http://epa.gov/climatechange/emissions/usinventoryreport.html},
\myurlb{www.epa.gov/cmop/}{http://www.epa.gov/cmop/},
\citet{JacksonCoalMethane}, \citet{ThakurCoalMethane}.
% global total emissions are 120 MMTCE (million metric ton carbon equiv?)
Global emissions of methane from coal mining are about 400\,Mt\,\COOe\ per year.
% 19,000 Gg of methane
% http://www.epa.gov/climatechange/economics/international.html#global_anthropogenic
% cf Coal, 20 GtCO2 per year globally.
This corresponds to roughly 2\% of the greenhouse gas emissions from burning the coal.
% http://www.coal.gov.uk/resources/cleanercoaltechnologies/CoalMineandbedmethane.cfm
The average methane content in British coal seams is 4.7\,m$^3$ per ton of coal
\citep{JacksonCoalMethane};
% Methane contents of British Coal seams vary from trace to 20 m^3/t. AVerage in 1993 was
% 4.7m^3/t.
%
% Sandstone rocks also contain methane, but usually the coal seams themselves
% have the dominant methane.
% Each 1t coal gives (44/12)t CO2 - 3.6t
% Methane density is 1.8kg/m**3 so that means 8.5 kg of methane per t of coal
% or about 180kg of CO2 equivalent which is 5\% in GHG terms
this methane, if released to the atmosphere, has a global warming potential
about 5\% of that of the \COO\ from burning the coal.
\setcounter{latestnotepage}{0}% hack to ensure page number given
\item[\npageref{pMethane88}]
{\nqs{If 5\% of the natural gas leaks, it's equivalent to
a 40\% boost in carbon dioxide}}.
Accidental methane pollution has nearly eight times as big
a global-warming effect
% \label{pMethane8}
as the \COO\ pollution that would arise from
burning the methane;
eight times, not the standard ``23 times,'' because
``23 times'' is the warming ratio between equal
{\em{masses}\/} of methane and \COO\@.
Each ton of CH$_4$ turns into 2.75 tons of \COO\ if burned;
if it leaks, it's equivalent to 23 tons of \COO\@.
And 23/2.75 is 8.4.
% , which is near enough eight.
\item[Further reading:]
World Energy Council
\tinyurl{yhxf8b}{http://www.worldenergy.org/wec-geis/publications/reports/ser/coal/coal.asp}
% http://www.worldenergy.org/wec-geis/publications/reports/ser/coal/coal.asp
% survey of energy resources.
% China and USA both produce and consume 1\,Gt coal per year (1999 figure).
\item[Further reading about
underground coal gasification:]
% UCG:
\tinyurl{e2m9n}{http://www.coal.gov.uk/resources/cleanercoaltechnologies/ucgoverview.cfm}
% http://www.coal.gov.uk/resources/cleanercoaltechnologies/ucgoverview.cfm
\end{notelist}
\ENDfullpagewidth
\normalsize
% source: New Scientist 23 Jan 1993
% coal is a renewable: it takes between 4000 and 100,000 y
% for 1m of peat to accumulate. One metre of coal comes from 10 metres of peat.
% Most coal is fossil peat. Peat only forms is special soggy conditions.
% opencast mines in Britain have proven reserves of 300 Mt coal, and 25Mt
% more are found each year.
% \part{Supply-side technology}
\gset\chapter{\gcol{Nuclear?}}
\label{ch.uranium}
\label{ch.fusion}
\myquote{
We\index{nuclear!weapon} made the mistake of lumping nuclear energy in with nuclear weapons, as if all things nuclear were evil. I think that's as big a mistake as if you lumped nuclear medicine in with nuclear weapons.
}{
Patrick Moore,\\
\hfill former Director of \ind{Greenpeace}\index{Moore, Patrick}
International
}
%% http://blogs.wsj.com/environmentalcapital/2008/04/17/moores-law-why-enviros-are-wrong-on-nuclear-power/?mod=WSJBlog
\noindent
Nuclear power comes in two flavours.
Nuclear {\em{fission}\/} is the flavour
that we know how to use in power stations; fission
% currently
\marginfig{
\begin{center}\small
kWh/d per person \\
\mbox{\epsfbox{metapost/nu.1}}
\end{center}
\caption[a]{Electricity\index{nuclear power!data by country}
generated per capita from nuclear
fission in 2007, in kWh per day per person,\index{data!nuclear power by country}
in each of the countries with nuclear power.\nlabel{fig.nuc}
}
\label{fig.nu}
}%
uses uranium, an exceptionally heavy element,
as fuel.
Nuclear {\em{fusion}\/} is the flavour that we
don't yet know how to implement in power stations;
fusion would use light elements,
especially hydrogen, as its fuel.
Fission reactions split up heavy nuclei into
medium-sized nuclei, releasing energy.
Fusion reactions fuse light nuclei into medium-sized
nuclei, releasing energy.
Both forms of nuclear power, fission and fusion, have an important property:
the nuclear energy available per atom is roughly one million times bigger
than the chemical energy per atom of typical fuels.
This means that the amounts of fuel and waste\index{waste!nuclear} that must
be dealt with at a nuclear reactor can be up to one million times smaller than
the amounts of fuel and waste at an equivalent fossil-fuel power station.
%``One million'' is dificult to grasp; l
Let's try to personalize these ideas.
The mass of the fossil fuels consumed by ``the average British person''
% coal: 87.5 M metric tonnes per year 4kg per day per person
% oil: 1.82 M bbl per day
% (1.82e6 / 60e6) * 136.43 4 kg per day per person
% gas: 91.16 billion cu m per year at 1.819 kg/m3
% 91.16e9 * 1.819 / 60e6 / 365.25 7.6kg per day per person
is about 16\,kg per day (4\,kg of coal, 4\,kg of oil, and 8\,kg of gas).
That means that every single day,
an amount of \index{fossil fuel!consumption}\index{consumption!fossil fuels}fossil fuels
with the same weight as 28 pints of milk is
extracted from a hole in the ground,\index{mining!coal}\index{coal mining}
transported, processed,
and burned somewhere on your behalf.\index{UK!fossil fuel consumption}
The average Brit's fossil fuel habit creates 11 tons per year
of waste carbon dioxide; that's 30\,kg per day. In the previous chapter
we raised the idea of capturing waste carbon dioxide, compressing it into
solid or liquid form, and transporting it somewhere for disposal.
%waste in several forms,
%including carbon dioxide, vented to the atmosphere, and ash at coal power stations.
Imagine that one person was responsible for capturing and dealing with all their own
carbon dioxide waste. 30\,kg per day of carbon dioxide
is a substantial rucksack-full every day -- the same weight as 53\,pints of milk!
% ((162 tonnes) / (GW * year)) * 115 kWh = 0.00212530207 kilograms
% 19 g per cc.
In contrast, the amount of natural uranium required to provide the same
amount of energy as 16\,kg of fossil fuels, in a standard fission reactor,
is 2 grams; and the resulting
waste weighs one quarter of a gram.
(This 2\,g of uranium
is not as small as one millionth of 16\,kg per day, by the way,
because today's reactors burn up less than 1\% of the uranium.)
To deliver 2 grams of uranium per day, the miners
at the uranium mine\index{mining!uranium}\index{uranium mining} would
have to deal with perhaps 200\,g of ore per day.
% 20 tons/162 tons
% tailings = 200g per day, assuming 1% ore.
% One French citizen's {\em{lifetime}\/} share of high-level nuclear waste has
% the size of a golfball.
So the material streams flowing into and out of nuclear reactors are
small, relative to fossil-fuel streams. ``Small is beautiful,''\index{small is beautiful}
but the fact that the nuclear
waste stream is small doesn't mean that it's not a problem; it's
just a ``beautifully small'' problem.
\section{``Sustainable'' power from nuclear fission}
\Figref{fig.nu} shows how much electricity was generated
globally by nuclear power in 2007, broken down by country.
Could nuclear power be ``sustainable''?
Leaving aside for a moment the usual questions
about safety and waste-disposal,
a key question is whether humanity could
live for generations
%10,000 years
on fission.
How great are the worldwide supplies of uranium, and
other fissionable fuels?
% of thorium?
%% see _nuclear.tex for refs
%% ESTIMATED conventional uranium reserves worldwide (proven+additional+speculative) are about 15 million tons
%% at a price up to US$ 130/kg.
%% - from http://www.ecolo.org/documents/documents_in_english/u_resources.htm
%% Source : NEA/IAEA RED BOOK 2003 (the RED BOOK "Uranium 2003: Resources, Production and Demand" can be ordered from the NEA - www.oecd.org, click on online bookstore)
%% rivers bring more uranium into the sea all the time, in
%% fact 3.2x10^4 tonne per year.
%
%% (which is 3.2e7 tonnes over 1000 years so much smaller than
%% amount in ocean that I used.)
% Me: So if 1tU is 1GWy(e) then this 32,000 t / y corresponds to
% 32,000 GW, if ALL collected. Plausible? 10%?
% 3200GW between 6G people is 1/2 kW each, or 12 kWh/d.
%% All the world's electricity usage, 650GWe
%% could therefore be supplied by the uranium in seawater for 7 million years.
%% Cohen calculates that we could take 16,000 tonne per year of uranium from seawater
%% and get 2x current world energy usage. (or 25x 650GWe, he says (16,000GW))
%% check:
%% (162 tonnes / 1GWy) * 115 kWh
%% Without breeding, 162 tonnes U per yr is 1GW.
%% 16,000 tonne per year -> 100 GW only.
%% with breeding, assuming 40x better, get
%% 4000\,GW. (I'll use 60)
%\section{Uranium fuel, long-term}
% Can nuclear energy be considered a `renewable' or `sustainable' source?
% Eventually we'll run out of \ind{uranium}. How long would that take?
Do we have only a few decades' worth of uranium, or do we have enough for millennia?
% spelling checked. millennium
%\begin{table}[hbtp]
%\figuremargin{
\margintab{\small
\begin{tabular}{lrr}
\toprule
%\multicolumn{3}{c}{Known Recoverable Resources of Uranium}\\\midrule
\multicolumn{2}{r}{\ \ \ million \tonnes}\\%& percentage \\
\multicolumn{2}{r}{\ \ \ uranium } \\%& of world total\\
\midrule% 2005 2003 figures 2005 undiscovered(2005)
Australia & 1.14 \\%& 24\%\\% &1074 &30\%\\% 747 + 396 --
Kazakhstan & 0.82 \\%& 17\%\\% &622 &17\%\\% 514 + 302 810
Canada & 0.44 \\%& 9\%\\% &439 &12\%\\% 345 + 99 850
USA & 0.34 \\%& 7\%\\% &102 & 3\%\\% 342 + 0 2613
South Africa & 0.34 \\%& 7\%\\% &298 & 8\%\\% 255 + 85 1223
Namibia & 0.28 \\%& 6\%\\% &213 & 6\%\\% 182 + 100 --
Brazil & 0.28 \\%& 6\%\\% &143 & 4\%\\% 158 + 121 800
Russian Federation & 0.17 \\%& 4\%\\% &158 & 4\%\\% 132 + 41 650
Uzbekistan & 0.12 \\%& 2\%\\% &93 & 3\%\\% 77 + 39 220
\midrule
World total\\
(conventional reserves\\
in the ground) & 4.7 %% 3\,537 (2003) %% 3297+1446 (2005)
\\
\midrule
% undiscovered resources include prognosticated resources and
% speculative resources - thought to exist in geolog favourable unexplored areas
% page 23 of RedBook2005
% Undiscovered resources & 10\,000 \\
Phosphate deposits & 22 \\
%% ref [6] in http://nuclearinfo.net/Nuclearpower/OneCompletePage
%% says 40 Mt U of which 4.7Mt at less than 130 $ per kg
\midrule
Seawater &4\,500 \\
\bottomrule
%% In today's plants, 22t uranium needed to produce 1 TWhe
\end{tabular}
%}{
\caption[a]{
Known recoverable resources of uranium.
The top part of the table shows the
``reasonable assured resources'' and ``inferred resources,''
at cost less than \$130 per kg of uranium, as of
1 Jan 2005.
%% TODO - clarify that the phosphate deposits are unconventional, more expensive
These are the estimated resources in areas where
exploration has taken place.\index{uranium!reserves}
There's also 1.3 million tons of depleted uranium
sitting around in stockpiles, a by-product of previous uranium activities.
% 2003 estimates of reasonably assured resources plus estimate additional resources
% at prices up to $80 per kg
% Known Recoverable Resources of Uranium.
% david king says reactors in the world today use 60,000 t/y total.
% and he agrees that another 14.4 million tons could prob be found by exploration.
% there's also phosphate deposits (22 Mt) and seawater (up to 4000Mt)
% David King says fast breeder is 60 more more times better.
% MOX means plutonium oxide and uranium MIX
% Thorium is 3 times as abundant as uranium
%% Source : NEA/IAEA RED BOOK 2003 (the RED BOOK "Uranium 2003: Resources, Production and Demand" can be ordered from the NEA - www.oecd.org, click on online bookstore)
%% via http://www.ecolo.org/documents/documents_in_english/u_resources.htm
}
\label{tab.Ureserve}
}%
%\end{table}
To estimate a ``sustainable'' power from uranium, I took
the total recoverable uranium in the ground and in \ind{seawater},
divided it fairly between 6 billion humans, and asked ``how
fast can we use this if it has to last 1000 years?''
% I'll be the first to admit this is an arbitrary definition
% of ``sustainable''! But I think the results are interesting
% anyway.
Almost all the recoverable uranium is in the oceans, not
in the ground:
seawater contains 3.3\,mg of uranium per m$^3$ of water, which
adds up to {4.5 billion tons worldwide}.
% In contrast, t
I called the uranium in the ocean ``recoverable'' but this
is a bit inaccurate -- most ocean waters are quite inaccessible,
and the \ind{ocean conveyor belt} rolls round only once every
1000 years or so;
and no-one has yet demonstrated uranium-extraction from seawater on
an industrial scale. So we'll make separate estimates for two
cases: first using only mined uranium, and second
using ocean uranium too.
The uranium ore in the ground that's extractable at prices
below \$130 per kg of uranium is
% three thousandths
about one thousandth
of this. If prices went above \$130 per kg, phosphate deposits that
contain uranium at low concentrations would become economic
to mine. Recovery of uranium from phosphates is perfectly possible,
and was done in America and Belgium before 1998.
% from WES:
% The uranium content of
%the world's sedimentary phosphates is estimated at nearly 15
%million tonnes, more than half of them in Morocco. To date
For the estimate of mined uranium, I'll add both the conventional
uranium ore and the phosphates, to give a total resource of
27 million \tonnes\ of uranium (\tabref{tab.Ureserve}).
We'll consider two ways
to use uranium in a reactor:
(a) the widely-used {\dem{\ind{once-through}
method}\/} gets energy mainly from the $^{235}$U\index{nuclear!reactor!once-through}
(which makes up just 0.7\% of uranium), and
discards the remaining $^{238}$U;
(b) {\sl\ind{fast breeder reactor}s\/}, which are
more expensive to build,
convert the $^{238}$U to fissionable plutonium-239 and obtain
roughly 60 times as much
energy from the uranium.\nlabel{pFast60}
% [Include reference.]
\subsection{Once-through reactors, using uranium from the ground}
A once-through%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=51.3mm\epsfbox{../../images/GraphiteReactor.eps}}}\\
\end{tabular} \\
\end{center}
\caption[a]{
Workers push uranium slugs into the X-10 Graphite Reactor.
}
}
%Workers use a rod to push uranium slugs into the concrete loading face of the X-10 Graphite Reactor. Historical US government photo.
{\bf one-gigawatt} {nuclear power station}\index{nuclear power!station} uses
{\bf 162 \ttonnes\ per year of uranium}.\nlabel{p162}
% in fact 195t is a GW year
% Or, to put it in human-sized units,
%% cf one tonne coal is 8000kWh of heat or 3000kWh elec
% {\bf one gram of natural uranium} yields {\bf 44\,kWh} of electricity.
% 44.3kWh per gramme
So the known mineable resources of uranium, shared between 6\,billion people,
would last for 1000 years if we produced nuclear power
at a rate of
%%
%% 0.54589
%\[ \mbox
{\OliveGreen{0.55\,kWh per day per person}.} %% 0.0708 was 0.083
%\]
This sustainable rate is the output of just 136 nuclear power stations, and is
half of today's nuclear power production.
It's very possible this is an underestimate of uranium's potential,
since, as there is not yet a
uranium shortage, there is no incentive for exploration
and little uranium exploration has been undertaken since the 1980s;
so maybe more mineable uranium will be discovered.
Indeed, one paper published in 1980 estimated that
the low-grade uranium resource
% in shales and phosphates
is more than 1000 times greater than the 27 million \tonnes\ we just assumed.\nlabel{UEstimate}
%
% the estimated conventional
% uranium reserves worldwide (proven, ``additional,''
% {\em{and}\/} ``speculative''),
% at a price up to \$130/kg,
% are about 15 million tons, about 4 times the figure I used;
%% source http://www.uic.com.au/Factsheet.htm
% but even if one hundred
% times more were discovered,\nlabel{one100} this technology would still
% supply only 7\,kWh per day
% per person of sustainable power.
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Three_Mile_Island.eps}}}\\
\end{tabular} \\
\end{center}
\caption[a]{
Three Mile Island nuclear power plant.
}
}%
Could our current once-through use of mined uranium
be sustainable? It's hard to say, since there is such uncertainty
about the result of future exploration. Certainly at today's
rate of consumption, once-through reactors could keep going for
hundreds of years. But if we wanted to crank up nuclear power
40-fold worldwide, in order to get off fossil fuels and
to allow standards of living to rise,
% 372 GW today nuclear world pwer is 15 TW
we might worry that once-through reactors are not a sustainable
technology.
% ; at the current rate of consumption of uranium,
% the estimated
% resource
% (proven, additional, and speculative)
% would last 240\,years.
% BEGIN BEGIN (see END)
{
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
\subsection{Fast breeder reactors, using uranium from the ground}
Uranium can be used 60\index{reactor!fast breeder}
% requested permission here and it was granted by John
% http://en.wikipedia.org/wiki/User_talk:John#Request_for_permission_to_use_Dounreay
% Dounreay Nuclear Power Development Establishment was established in 1955 primarily to pursue the UK Government policy of developing fast breeder reactor (FBR) technology
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/DounreayJM.eps}}}\\
\end{tabular} \\
\end{center}
\caption[a]{
\ind{Dounreay} Nuclear Power Development Establishment,
whose primary purpose was the development of \ind{fast breeder reactor} technology.
Photo by John Mullen.\index{reactor!fast breeder}\index{breeder reactor}
}
}%
times more efficiently in\index{breeder reactor}
fast breeder reactors,\index{fast breeder reactor}
which burn up all the uranium --
both the $^{238}$U and the $^{235}$U (in contrast to
the once-through
reactors, which burn mainly $^{235}$U).\index{nuclear reactor!fast breeder}
As long as we don't chuck away the spent fuel
that is spat out by once-through
reactors, this source of depleted\index{uranium!depleted}
uranium could be used too, so uranium that
is put in once-through reactors need not be wasted.
If we used all the mineable uranium (plus the depleted uranium stockpiles) in
% switched to
60-times-more-efficient fast breeder reactors,
the power would be
%\[%% 4.245 \mbox
{\OliveGreen{33\,kWh per day per person}.}
%\]
\begin{figure}
\figuredangle{
\mbox{\epsfbox{metapost/stacks.343}}
}{
\caption[a]{``Sustainable'' power from uranium.
For comparison, world nuclear power production today
is 1.2\,kWh/d per person. British nuclear power production
used to be 4\,kWh/d per person and is declining.}
\label{fig.usummary}% 420
}
\end{figure}
Attitudes to fast breeder reactors range from ``this is a dangerous
failed experimental technology whereof one should not speak'' to
``we can and should start building breeder
\index{nuclear!reactor!breeder}\index{reactor!fast breeder}reactors right away.''
I am not competent to comment on the risks of breeder technology,
and I don't want to mix \index{ethics!breeder reactor}ethical assertions with factual assertions.
My aim is just to help understand the numbers.
The one ethical position I wish to push is ``\ind{we should have a plan
that adds up}.''\index{plan}
\subsection{Once-through, using uranium from the oceans}
% A {\bf one-gigawatt} nuclear power station uses {\bf 162 \tonnes\ per year of uranium}.
The oceans' uranium, if completely extracted and used in
once-through reactors, corresponds to a total energy of
\[
\frac{ \mbox{ 4.5\,billion tons per planet } }
{ \mbox{ 162 \tonnes\ uranium per GW-year } }
= \mbox{ 28 million GW-years per planet}.
\]
How fast could uranium be extracted from the oceans?
The oceans circulate slowly: half of the water is in the Pacific Ocean,
and deep Pacific waters circulate to the surface on the great ocean
conveyor only every 1600 years. Let's imagine that 10\% of the uranium
is extracted over such a 1600-year period.
That's an extraction rate of 280\,000 tons per year.
In once-through reactors,
this would deliver power
at a rate of
\[
\mbox{ 2.8 million\,GW-years / 1600 years } = 1750\,\GW,
\]
which, shared between 6\,billion people, is
%\[ \mbox
\OliveGreen{7\,kWh per day per person}.
%\]
(There's currently 369\,GW of nuclear reactors, so this figure
corresponds to a 4-fold increase in nuclear power over today's levels.)
%% http://www.uic.com.au/Factsheet.htm
I conclude that ocean extraction of uranium would turn today's once-through
reactors into a ``sustainable'' option -- assuming that the uranium
reactors can cover the energy cost of the ocean extraction process.
\subsection{Fast breeder reactors, using uranium from the oceans}
If fast reactors are 60 times more efficient, the same extraction of ocean uranium
could deliver
%\[ \mbox
\OliveGreen{420\,kWh per day per person}.
%\]
At last, a sustainable figure that beats current consumption! --
but only with the joint help
of two technologies that are respectively scarcely-developed
and unfashionable: ocean extraction of uranium, and
fast breeder reactors.
\subsection{Using uranium from rivers}
The uranium in the oceans is being topped up by \index{river!uranium}rivers, which deliver
uranium at a rate of 32\,000 tons per year.
If 10\% of this influx were captured,
% 3200 / 162
it would provide enough fuel for 20\,GW of once-through reactors, or 1200\,GW
of fast \ind{breeder reactor}s.
The fast breeder reactors would deliver
%\[
\OliveGreen{5\,kWh per day per person.} %% 4.74
% \]
%% 0.08 kWh/d each for the once-throughs
All these numbers are summarized in \figref{fig.usummary}.
\subsection{What about costs?}
As usual in this book, my main calculations have paid little attention to
economics. However, since the potential contribution of ocean-uranium-based power
is one of the biggest in our ``sustainable'' production list,
it seems appropriate to discuss whether this uranium-power figure is at all
economically plausible.\index{nuclear power!costs}
%THIS SECTION NEEDS REWRITING. It currently assumes no breeder reactors.
%
% At a rate of {110\,kWh per day per person,}
% all the recoverable uranium ore would be mined within one year.
% So the long-term viability of uranium-power depends on
% the seawater option.
%% find more images here... seawater
%% http://www.jaeri.go.jp/jpn/publish/01/ff/ff39/gif/ff3902.gif
Japanese researchers have found a technique for
extracting \index{uranium!extraction from seawater}\index{seawater!uranium extraction}uranium
from seawater at a cost of\index{ocean!uranium extraction}
% Recent Japanese work (May 1998) projects a cost of
\$100--300 per kilogram of uranium\nlabel{pagejaps},
in comparison with a current cost of
about \$20/kg
for uranium from ore.
% But the seawater resource in
% enough to operate 10,000 power reactors for 1000 years
% (without breeding).
Because uranium contains so much more energy per \tonne\ than
traditional fuels, this 5-fold or 15-fold
increase in the cost of uranium\index{uranium!cost}\index{nuclear power!costs}
would have little effect on the cost of nuclear power: nuclear power's price is
dominated by the cost of power-station construction
and \index{nuclear power!decommissioning}decommissioning, not
by the cost of the fuel.
Even a price of \$300/kg would increase the cost of nuclear energy by only about 0.3\,p
per kWh.
%
The expense of {uranium extraction} could be reduced by combining
it with another use of {seawater} -- for example, power-station cooling.\nlabel{pUextCool}
}
% END of troublesome page hack (see BEGIN)
We're not home yet: does the Japanese technique scale up?
What is the energy cost of processing all the seawater?
% required for a single gigawatt reactor?
In the Japanese experiment, three cages full of adsorbent
uranium-attracting material weighing
350\,kg collected ``more than 1\,kg of yellow cake in 240 days;''
this figure corresponds to about 1.6\,kg per year.
The cages had a cross-sectional area of 48\,m$^2$.
To power a once-through 1\,GW nuclear power
station,\index{nuclear power!station!fuel required} we need 160\,000\,kg per year,
which is a production rate 100\,000 times greater than the Japanese
experiment's. If we simply scaled up the
Japanese technique, which accumulated uranium passively from
the sea, a power of 1\,GW would thus need cages
having a collecting
area of 4.8\,km$^2$ and containing a
weight of 350\,000 \tonnes\ of adsorbent material -- more than the
weight of the steel in the reactor itself.
To put these large numbers in human terms, if uranium were delivering, say,
{22\,kWh per day per person,}
each 1\,GW reactor would be shared between 1 million people,
each of whom needs 0.16\,kg of uranium per year.
So each person would require one tenth of the Japanese experimental facility,
with a weight of 35\,kg per person, and an area of \areacol{5\,m$^2$} per person.
The proposal that such uranium-extraction facilities should be created
is thus similar in scale to proposals such as ``every person should have
\areacol{10\,m$^2$} of solar panels'' and ``every person should have
a one-\tonne\ car and a dedicated parking place for it.''
A large investment, yes, but not absurdly off scale.
And that was the calculation for once-through reactors.
For fast breeder reactors, 60 times less uranium is required, so the mass
per person of the uranium collector would be 0.5\,kg.
% $\half$\,kg.
% cut material to _uranium.tex
\section{Thorium}
%\begin{table}
%\figuremargin{
\margintab{
\begin{center}
\begin{tabular}{lr}
\midrule
Country & Reserves \\
\multicolumn{2}{r}{(1000 \tonnes)} \\
\midrule
Turkey & 380 \\
Australia & 300\\
India &290\\
Norway &170\\
USA &160\\
Canada &100\\
South Africa & 35\\
Brazil &16\\
Other \makebox[0in][l]{countries} & 95
\\ \midrule
World total & 1\,580\\
\bottomrule
\end{tabular}
\end{center}
%}{
\caption[a]{
% Left:
Known world \index{thorium!resources}{thorium} resources in \ind{monazite}
(economically extractable).
% Right: Estimated thorium reserves and additional resources.
% source WEA ch 5 , citing BGR Data Bank
\label{pMonazite}
}
}%
%\end{table}
% There are two ways to boost our estimates of the potential
% contribution of nuclear fission. Both require further development,
% and both seem technically feasible.
% First, standard uranium-powered nuclear reactors leave most of
% their uranium (the U-238) unused. An alternative reactor design
% using `fast' neutrons, known as a breeder reactor,
% can use U-238. If uranium ore runs low, it seems likely
% that these `fast' reactors could be perfected, and would deliver 60 times more
% energy per \tonne\ of uranium than standard reactors.
% Fast reactors could be fed the U-238 that is discarded
% from standard reactors.
% Second,
{\index{thorium}{Thorium}} is a radioactive element similar to uranium.
Formerly used to make \ind{gas mantle}s,
it is about three times as abundant in the
earth's crust as \ind{uranium}.
Soil commonly contains around 6 parts per million of thorium,
and some minerals contain 12\% \ind{thorium oxide}.
Seawater\index{seawater} contains little thorium, because
thorium oxide is insoluble.
Thorium can be completely burned up in simple reactors
% without fast neutrons
(in contrast to standard uranium reactors which
use only about 1\% of natural uranium).
Thorium is used in nuclear reactors in \ind{India}.
If uranium ore runs low, thorium will probably
become the dominant nuclear fuel.
% 170000*24 MWh per tonne
Thorium reactors deliver
$3.6$ billion kWh
% $3.6\times10^9$\,kWh
of heat per \tonne\ of thorium,
which implies that a 1\,GW reactor requires
about 6 \tonnes\ of thorium per year, assuming its generators are
40\% efficient.\nlabel{pThoriumR}
% Rubbia says
% the ``EA'' would be 3.65 tonnes of oxide per year for a GW (thermal) reactor
% ref: Rubbia et al document. (claim this is about 250 x more efficient
% than stnadard once-through PWR)
%% then later says
%% (0.78 ton Thorium for 3GWy(th) ( vs. 200 tons of uranium for 3 GW th )
%% ie 0.78 ton Thorium for 1.2GWy(e)
%%% ie 0.65 tonn per GWy
%
% 3.6e9 kWh / tonne
% is 0.41 GWy / tonne
% is equiv to 2.435 tonnes per GWy (heat)
% is equiv to 6.08 tonnes per GWy (elec) (Assuming 40%)
% that is heat.
% burnups of 150,000 MWd/t were achieved.
% burnups of 150 GWd/t were achieved.
%
% cf uranium LWRs achieve a ``burnup'' of 50GWdays per \tonne\ of fuel. (enriched???)
% from http://www.world-nuclear.org/info/inf62.html?terms=thorium
% got 170,000 MWd/t burn-up
%% more facts:
% Worldwide thorium resources, which are listed by major deposit type in Table 10.1, are estimated
% to total about 6 078 000 tTh though no economic potential is implied for the resources listed.
%% A 1GW reactor requires 10 tonnes per year of Th.
%% see _nuclear for 40 year red book source
Worldwide thorium resources are estimated
to total about\index{thorium!reserves}
6 million \tonnes, four times more than the known reserves
shown in \tabref{pMonazite}.
% (\Tabref{pMonazite} shows the locations
% of 1.6 million \tonnes\ of proven reserves.)
As with the uranium resources, it seems plausible that
these thorium resources are an underestimate, since thorium prospecting
is not highly valued today.
% 6.1\,million \tonnes.
% The economically extractable reserves of thorium
% exceed 3\,million \tonnes.
%% http://www.ecolo.org/documents/documents_in_english/u_resources.htm
%% says Thorium reserves and resources are estimated to be well over 4.5 million tons
% pr 6.1e6 * 3.6e9*0.4 / 6e9 / 1000.0 / 365.25
% 4.00
%% the rubbia documents agrees, 6 million \tonnes. (page 16)
%% they say the EA could produce 10TW from this thorium for 1250 years
If we assume, as with uranium, that these resources are used up over 1000 years
and shared equally among 6 billion people,
we find that the ``sustainable'' power thus generated is
{\OliveGreen{4\,kWh/d per person}}.
\marginfig{
\mbox{\epsfbox{metapost/stacks.344}}
\caption{Thorium options.}
}
An\index{nuclear!reactor!energy amplifier}
alternative nuclear reactor for thorium, the ``\ind{energy amplifier}''
or ``\ind{accelerator-driven system}''
proposed by Nobel laureate Carlo\index{Rubbia, Carlo}
Rubbia and his colleagues\nlabel{pRubbiaEt}
% Rubbia et al,
would, they estimated, convert
6 million \tonnes\ of thorium to 15\,000\,TWy of energy, or
%% 10 TW is world power they say
{{60\,kWh/d per person}} over 1000 years.
Assuming conversion to electricity at 40\% efficiency, this would
deliver
{\OliveGreen{24\,kWh/d per person}} for 1000 years.
And the waste from the energy amplifier would be much less
radioactive too.
They argue that, in due course, many times more thorium would
be economically extractable than the current 6 million \tonnes.
If their suggestion -- 300 times more -- is correct, then
thorium and the energy amplifier could offer
120\,kWh/d per person for 60\,000 years.
% (Rubbia page 16)
% about 1\% of the power generated is needed to run the accelerator
\section{Land use}
Let's imagine that Britain decides it is serious about getting
off fossil fuels, and creates a lot of new nuclear reactors, even though
this may not be ``sustainable.'' If we build enough reactors
to make possible a significant decarbonization of transport
and heating,
% to consume more than its `fair share' of uranium, as defined above.
can we fit the required nuclear reactors into Britain?
The number we need to know is the power per unit area of nuclear power stations,
which is about \pdcol{1000\,\Wmm} (\figref{pdNuk}).
Let's imagine generating
22\,kWh per day per person of nuclear power --
equivalent to
%% cf USA has 91GW , France has 63GWe, germany has 21GW, sweden 9GW. belgium 6, spain 8
%% south korea has 16GW and japan has 45GW
55\,GW (roughly the same as France's nuclear power),
which could be delivered by 55
nuclear power stations, each occupying one square kilometre.
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/sizewell.eps}}\\
{\mbox{\epsfxsize=53mm\epsfbox{../../images/sizewell-along-beach.eps}}}\\
\end{tabular} \\
\end{center}
\caption[a]{
\ind{Sizewell}'s power stations.\index{reactor}
Sizewell A, in the foreground,
had a capacity of 420\,MW, and
was shut down at the end of 2006. Sizewell B, behind, has
a capacity of 1.2\,GW\@.
Photo by William Connolley.
}
}%
\marginfig{
\begin{center}
\begin{tabular}{c}
\lowres{\epsfxsize=50mm\epsfbox{../../images/Sizewell.eps}}%
%{\epsfxsize=50mm\epsfbox{../../images/Sizewell.eps}} \\
{\leveltwo{\epsfxsize=50mm\epsfbox{../../images/Sizewell2.eps}}%
{\epsfxsize=50mm\epsfbox{../../images/Sizewell3.eps}}} \\
%% best size by far (eps) is the Sizewell3 (level 3) option
\end{tabular}
\end{center}
\caption[a]{
% Sizewell power station\index{nuclear power!station!area} has a capacity of
% about 1.2\,GW, and occupies less than 1\,km$^2$.
Sizewell occupies less than 1\,km$^2$.
The blue grid's spacing is 1\,km.
\copyright\ Crown copyright; Ordnance Survey.
}\label{pdNuk}
}%
That's about 0.02\% of the area of the country. Wind farms delivering
the same average power would require 500 times as much land: 10\% of the country.
If the nuclear power stations
were placed in pairs around the coast (length about 3000\,km,
at 5\,km resolution),
%% , for convenience),
then there'd be two every 100\,km.
% (The length of the coastline of the British mainland,
% at 5\,km resolution, is about 3000\,km)
% England and Wales, at 5\,km resolution,
% is roughly $704 \times 5\,km \simeq 3500\,km$.
% I measured the mainland myself
% using 96 line segments and got 3691km.)
% But I don't want to include islands.)
% {\durl{http://www.angliacampus.com/public/sec/geog/coastln/page14.php}}
%% 18000 km is also a popular figure.
Thus while the area required is modest,
the fraction of coastline gobbled by these power stations
would be about 2\% (2 kilometres in every 100).
% (There are already 17 nuclear power station sites in the UK.)
\section{Economics of cleanup}
%Cleanup costs for nuclear fission. When
% I met
% Tony Benn, the Minister who authorized the start of Nuclear
% Power in the UK, said he felt he had been hoodwinked by civil
% servants regarding the cost of nuclear fission; he thought the
% true motivation had been weapons not electricity, and that he would
% not authorize the start of nuclear power had he known what he knows
% now.
% Reservations about nuclear power's association with
% military applications are well known.
% *** CLEAN UP ME
% \citet{Hodgson99}
% Hodgson Page 102
% quotes 0.54p/kWh as the cost of decommissioning.
What's the cost of cleaning up nuclear power sites?\nocite{Hodgson99}
\index{nuclear power!costs}The
\ind{nuclear decommissioning authority} has an annual budget
of \pounds2 {{billion}} for the next 25 years.\nlabel{pCleanup} The nuclear
industry sold everyone in the UK 4\,kWh/d for about 25 years\nlabel{NukTot},
so the
nuclear decommissioning authority's cost is
% (25/25) * 2e11p/(60e6 people)/(365*4 kWh) =
2.3\,p/kWh. That's a hefty subsidy -- though not, it must be said,
as hefty as
the subsidy currently given to offshore wind (7\,p/kWh).
% 47 pounds * 1.5
% Hmm, I wasn't expecting 50 billion pounds to be such a small figure
% when expressed in p/kWh! I thought it would be bigger, since 50
% billion is roughly 1000 pounds each, and that sounded like a lot of
% electricity. But a kilowatt for 25 years costs 11,000 pounds at 5p
% per unit, so I was wrong.
%% source: Salter 2zazd7
Moreover, most of this nuclear clean-up cost is associated with
weapons-making facilities, not with civilian power stations.
% Double-check calculation:
% 10\,GW for 25 years.
% 10\,GW is not 1kW each.
% It's 0.166\,kW each.
% If the 25 year lifetime is accurate, that's a decommissioning cost
% of 2.3p/kWh.
%
% That's a lot, after all.
% It's 4 times as much as Hodgson figure.
%%% see _nuclear.tex
\section{Safety}
The safety of nuclear operations in Britain remains a concern.
The THORP reprocessing\index{reprocessing of nuclear waste}\index{nuclear waste!reprocessing}
facility at Sellafield, built in 1994
at a cost of \pounds 1.8\,billion, had a growing leak
from a broken pipe from August 2004 to April 2005. Over eight
months, the leak
let {\MidnightBlue{\em{85\,000 litres}\/}}
of uranium-rich fluid flow into a sump which
was equipped with safety systems that
were designed to detect immediately
any leak of as little as {\MidnightBlue{\em{15 litres}}}. But the
leak went undetected
because the operators hadn't completed the checks that ensured the
safety systems were working; and the operators were in the habit
of ignoring safety alarms anyway.
The safety system came with belt and braces.
Independent of the failed safety alarms,
routine safety-measurements of fluids in the sump should have detected
the abnormal presence of uranium within one month of the start of
the leak; but the operators often didn't bother taking these routine
measurements, because they felt too busy; and when they {\em{did}\/}
take measurements
that detected the abnormal presence of uranium in the sump
(on 28 August 2004, 26 November 2004, and 24 February 2005),
no action was taken.
By April 2005, \MidnightBlue{{\em{22 tons}\/}} of uranium had leaked, but
still none of the leak-detection systems detected the leak.
The leak was finally detected by {\em{accountancy}}, when the bean-counters
noticed
that they were getting 10\% less uranium out than their clients
claimed they'd put in!
Thank goodness this private company had a profit motive, hey?
The criticism from the Chief Inspector of Nuclear Installations was
withering:
% As the Inspector's report says,
``The Plant was operated in a culture that seemed to allow
instruments to operate in alarm mode rather than questioning the alarm and
rectifying the relevant fault.''\nlabel{pThorp}
% the leak itself also originated in new accountancy practices --
% weighing of big tanks, to measure how much fluid there was, which
% meant tanks were free-floating and moved around more, stressing their
% inlet pipes.
If we let private companies build new reactors,
how can we ensure that
% they don't employ a bunch of Homers like Sellafield
higher safety standards are adhered to?
I don't know.
% \myurl{http://www.hse.gov.uk/nuclear/thorpreport.pdf}
%% from http://www.hse.gov.uk/nuclear/thorp.htm
At the same time, we must not let ourselves be swept off our
feet in horror at the danger of nuclear power.
Nuclear power is not infinitely dangerous. It's just dangerous,\nlabel{pRisk}
much as coal mines, petrol repositories, fossil-fuel burning and wind
turbines are dangerous.
Even if we have no guarantee against nuclear accidents in the
future, I think the right way to assess nuclear is to compare it
objectively
% quantitatively
with other sources of power.
Coal power stations, for example, expose the public
to nuclear radiation, because coal ash\index{coal!nuclear radiation from}
typically contains uranium.\nlabel{pCoalNu}\index{nuclear radiation!from coal power}
Indeed, according to a paper published in the journal {\em{Science}},
% \citet{CoalIsNuke},
people in America living near coal-fired power stations
are exposed to higher radiation doses than those
living near nuclear power plants.
When quantifying the public risks of different power sources, we need a new
unit.
% I'm pretty sure
I'll go with ``deaths per GWy (gigawatt-year).'' Let me try to convey
what it would mean if a power source had a death rate of
1 death per GWy.
% But another idea would be to talk of nano-deaths per kWh? 1 death per TWh is
% the same as one nano-death per kWh.
% k M G T
% These could then be compared with the micro-deaths per plane-trip.
One gigawatt-year is the energy produced by a 1\,GW power station,
% or 1\,GW nuclear reactor (like Sizewell B)
if it operates flat-out for one year. Britain's electricity consumption
is roughly 45\,GW, or, if you like, 45\,gigawatt-years per year.
So if we got our electricity from sources with a death rate of
1 death per GWy, that would mean the British electricity supply system was
killing 45 people per year. For comparison, 3000 people die per year
on Britain's roads. So, if you are {\em{not}\/} campaigning for
the abolition of roads, you may deduce that
``1 death per GWy'' is a death rate that, while
sad, you might be content to live with.
% http://www.timesonline.co.uk/tol/comment/leading_article/article3621498.ece
% another statistic:
% carbon monoxide poisoning due to faulty domestic gas boilers %G–%@ this predictably results in roughly 50 prompt fatalities per year in the UK.
%
Obviously, 0.1 deaths per GWy would be preferable,
but it takes only a moment's reflection to realize that, sadly,
fossil-fuel energy production must have a cost
greater than 0.1 deaths per GWy -- just think of disasters on oil rigs;
helicopters lost at sea; pipeline fires; refinery
explosions; and coal mine accidents: there are tens of fossil-chain
fatalities per year in Britain.
% 380 over 20 years is 19 per year.
\marginfig{% was deaths.eps
\begin{center} \vspace{-2.5mm} \par
\mbox{\epsfxsize=47.5mm\epsfbox{../data/deathsL.eps}} \\
\end{center}
% }{
\caption[a]{Death rates of electricity generation technologies.
\Blue{$\times$}: European Union estimates by the ExternE project.
\Red{$\ocircle$}: Paul Scherrer Institute.
% $\odot
}
\label{fig.death}
}
So, let's discuss the actual death rates of a range of
electricity sources. The death rates vary a lot from country to
country. In China, for example, the death rate in coal mines,
per ton of coal delivered, is 50 times that of most nations.
Figure \ref{fig.death} shows numbers from
studies by the Paul Scherrer Institute and by a European Union
project called ExternE, which made comprehensive estimates of all the
impacts of energy production.
% Figure \ref{fig.death} shows their estimates on a logarithmic scale.
According to the EU figures,
coal, lignite, and oil have the highest death rates, followed by
peat and biomass-power, with death rates above 1 per GWy.
Nuclear and wind are the best, with death rates below 0.2
per GWy.\nlabel{pWN} Hydroelectricity is the best of all according
to the EU study, but comes out worst in the Paul Scherrer Institute's study,
because the latter surveyed a different set of countries.
\subsection{Inherently safe nuclear power}
Spurred on by worries about nuclear accidents,
engineers have devised many new reactors with improved
safety features. The GT-MHR power plant, for example, is
claimed to be inherently safe; and, moreover it has a higher
efficiency of conversion of heat to electricity than
conventional nuclear plants
[\myurlb{gt-mhr.ga.com}{http://gt-mhr.ga.com/}].
% ``Conventional, low-temperature nuclear plants operate at about 32\%
% thermal efficiency. GT-MHR power plants can achieve thermal efficiencies of close to 50\% now, and even higher efficiencies in the future.''
\marginfig{
\begin{center}
%% see W.gnu
\mbox{\epsfxsize=53mm\epsfbox{../../images/ChernobylCol.jpg.jpg.eps}} \\[0.1in]
\mbox{\epsfxsize=53mm\epsfbox{../../images/Chernobyl4.jpg.jpg.eps}} \\[0.1in]
\mbox{\epsfxsize=53mm\epsfbox{../../images/PrypiatAndNuclearPlant.jpg.jpg.eps}} \\[0.1in]
\mbox{\epsfxsize=53mm\epsfbox{../../images/PrypiatSt.jpg.jpg.eps}} \\
\end{center}
\caption[a]{Chernobyl power plant (top), and the abandoned town of
Prypiat, which used to serve it (bottom).
Photos by Nik Stanbridge.
}
\label{fig.chern4}
}
\section{Mythconceptions}
Two widely-cited defects
% of nuclear people often point out the various `huge'
of nuclear power are construction costs, and waste.
Let's examine some aspects of these issues.
\qa{Building a nuclear power station requires {\em{huge}\/} amounts
of concrete and steel,\index{nuclear power!station!construction}
materials whose creation
involves {\em{huge}\/} \COOem\ pollution.
}{
The steel and concrete
in a 1\,GW nuclear power station
have a carbon footprint of roughly
300\,000\,t\,\COO.\nlabel{pNukeCOO}
Spreading this ``huge'' number over a 25-year reactor life we
can express this contribution
to the carbon intensity in the standard units (g\,\COO\ per \kWhe),
% TBC - cross ref?
\beqa
\mbox{\begin{tabular}{c}carbon intensity\\
associated with construction\\ \end{tabular}}
&=&
\frac{\mbox{$300\times 10^{9}$\,g}}{ 10^6\,\kWe \times 220\,000\,\h }
\\
&=& 1.4\,\mbox{g/\kWhe},
\eeqa
which is much smaller than the fossil-fuel benchmark of
400\,g\,\COO/\kWhe. The \ind{IPCC}
estimates that the {\em{total}\/} carbon intensity of nuclear power
(including construction, fuel processing, and decommissioning)
is less than
40\,g\,\COO/\kWhe\ \citep{IPCCwg3ch4}.% page 283 (my page 33) and 269
Please don't get me wrong: I'm not trying to be
pro-nuclear. I'm just pro-arithmetic.
% (Could compare with the steel and concrete requirements of offshore wind too.)
%% _offshore.tex for notes
}
% Very nasty, but very very small.
% TBC -- see nuclearwaste.tex
%Waste:
%Let's compare three things: the above two, and the
%volume of household waste for landfill that we currently produce,
%compared with the volume of nuclear waste if we got all our power
%from nuclear. Or, say 50\,kWh/d/p.
\qa{Isn't the waste from nuclear reactors a huge problem?}
{
As we noted in the opening of this chapter, the volume of
waste\index{nuclear waste}\index{waste!nuclear} from nuclear reactors is relatively small.
Whereas the \ind{ash}
from ten coal-fired power stations\index{waste!from coal} would have a mass
of four million tons per year
% (67\,kg per person per year),
(having a volume of roughly 40 litres per person per year),
% 1.6 g per cm**3
% 1.6 kg per litre
the nuclear waste from Britain's ten nuclear power stations
has a volume of just 0.84\,litres per person per year
-- think of that as a \ind{bottle of wine}\index{wine-bottle}
per person per year (\figref{fig.waste1}).
Most of this waste is low-level waste. 7\% is intermediate-level waste,
and just 3\% of it -- 25\,{\ml} per year -- is high-level waste.
% so in volume terms that is 0.0006 of the coal volume
The high-level waste is the really nasty stuff.
It's conventional to keep the high-level waste at the reactor for its
first 40 years. It is stored in pools of water and cooled.
After 40 years, the level of radioactivity has dropped
1000-fold. The level of radioactivity continues to fall;
%% erratum: insert
if we {\dem{reprocess}\index{reprocessing of nuclear waste}\/} the waste,
separating off the uranium and plutonium for use in new nuclear fuel, then
after 1000 years, the radioactivity of the
high-level waste is about the same as that of uranium ore. Thus
waste storage engineers need to make a plan to secure high-level waste
for about 1000 years.
Is this a difficult problem? 1000 years is certainly a long time compared with
the lifetimes of governments and countries!
But the volumes are so small, I feel nuclear waste is only a minor
worry, compared with all the other forms of waste we are inflicting on future generations.
At 25\,{\ml} per year, a lifetime's worth of high-level nuclear waste would
amount to less than 2 litres.
% 1.75litres
Even when we multiply by 60 million people, the lifetime volume of nuclear waste
doesn't sound unmanageable: 105\,000 cubic metres. That's the same volume
as 35 olympic swimming pools. If this waste were put in a layer one metre deep,
it would occupy just one tenth of a square kilometre.
\marginfig{
\mbox{\epsfbox{metapost/waste.1}}
\caption[a]{British nuclear waste, per person, per year, has a volume
just a little larger than one wine bottle.}
\label{fig.waste1}
}
There are already plenty of places that are off-limits to humans.
% Humans
% are meant to stay away from Gruinard Island in Scotland, because it was
% used for an anthrax experiment in 1942.
I may not trespass in your garden. Nor should you in mine.
We are neither of us welcome in Balmoral.
``Keep out'' signs are everywhere.
Downing Street, Heathrow airport, military facilities, disused mines -- they're
all off limits. Is it impossible to imagine making another
one-square-kilometre spot -- perhaps deep underground
-- off limits for 1000 years?
Compare this 25\,{\ml} per year per person of high-level nuclear waste
with the other traditional forms of waste we currently dump:
municipal waste -- 517\,kg per year per person;
hazardous waste -- 83\,kg per year per person.\nlabel{WasteP}
People sometimes compare possible new nuclear waste
with the nuclear waste we already have to deal with, thanks to our existing old
reactors.
Here are the numbers for the UK.
The projected volume of ``higher activity wastes''
up to 2120, following decommissioning of
existing nuclear facilities,
is 478\,000\,m$^3$.
% five albert halls
Of this volume, 2\%
%9440
(about 10\,000\,m$^3$) will be the high level
waste (1290\,m$^3$) and spent fuel (8150\,m$^3$)
that together contain
92\% of the activity.
% also 3270 m3 of separated plutonium
% which would be used up in the MOX fuel of new
% reactors
% and 74 950 m3 of uranium
%
Building 10 new nuclear reactors (10\,GW)
would add another 31\,900\,m$^3$ of spent
fuel to this total.
That's the same volume as ten swimming pools.
% 50 25 2.5 is 3125
}
\qa{If we got lots and lots of power from nuclear fission or fusion, wouldn't this
contribute to global warming, because of all the extra energy
being released into the environment?
}{
That's a fun question. And because we've carefully expressed everything
in this book in a single set of units, it's quite easy to answer.
First, let's recap the key numbers about global energy balance from
\pref{pKeyGW}: the average solar power absorbed by atmosphere, land, and oceans
is 238\,\Wmm; doubling the atmospheric \COO\ concentration
would effectively increase the net heating by 4\,\Wmm.
This 1.7\% increase in heating is believed to be bad news
for climate.
Variations in solar power during the 11-year solar cycle
have a range of 0.25\,\Wmm.
% source: page 12 of hansen note / blog.
% hansen reckons a reasonable guess of climate sensitivity is 3C for doubled CO2,
% and 3/4 C per W/mm
So now let's assume that in 100 years or so,
the world population is 10\,billion, and everyone is living
at a European standard of living, using 125\,kWh per day
derived from fossil sources, from nuclear power, or from mined
geothermal power.
The area of the earth per person would be
% 510,065,600 km2 / ten billion in m2
51\,000\,m$^2$.
% 125 kWh / day / (510,065,600 km**2 / ten billion) in W/m**2
% is 0.1\Wmm
Dividing the power per person by the area per person, we find that
the extra power contributed by human energy use
would be 0.1\,\Wmm. That's one fortieth of the 4\,\Wmm\ that
we're currently fretting about, and a little smaller than
the 0.25\,\Wmm\ effect of solar variations. So yes, under these assumptions,
human power production would {\em{just}\/} show up as a contributor
to global climate change.
% Hansen: The current rate of atmospheric CO2 increase is
% ~2 ppm/year, yielding an annual increase of climate forcing
% of about +0.03 W/m2 per year.
}
\qa{
I heard that nuclear power can't be built at a sufficient rate to
make a useful contribution.}{
The difficulty of building nuclear power fast has been
exaggerated with the help of a \ind{misleading presentation} technique I call
``the magic playing field.''\index{magic playing field}\index{presentation, misleading}
\marginfignocaption{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Nuclear_Power_PlantME.eps}}}\\
\end{tabular} \\
\end{center}
%\caption[a]{ }
% Anna Gomez, Nuclear Energy Institute, Media@nei.org 9/227/2005 - Typical two-unit nuclear power plant with cooling tower, turbine building and reactor
% Free of copyright, modified by me.
}%
In this technique, two things appear to be compared, but the basis of
the comparison is switched halfway through.
The Guardian's
environment editor, summarizing a report from the
{\em{Oxford Research Group}},\label{MPF2}
wrote
% Again the magic playing field is used to try to knock nuclear power:
``For nuclear power to make any significant contribution to a reduction in global
carbon emissions in the next two generations, the industry would have
to construct nearly 3000 new reactors -- or about one a week for 60 years.
A civil nuclear construction and supply programme on this scale is a pipe dream, and
completely unfeasible. The highest historic rate is 3.4 new reactors a
year.''
3000 sounds much bigger than 3.4, doesn't it!
In this application of
the ``magic playing field'' technique, there is a switch
not only of {\timecolor{timescale}} but also of {\areacolor{\em{region}}}.
While the first figure (3000 new reactors {\timecolor{over 60 years}})
is the number required
{\areacolor{\em for the whole planet}},
the second figure (3.4 new reactors {\timecolor{per year}})
is the maximum rate of building by a {\areacolor{\em single country\/}}
(France)!
%% http://www.guardian.co.uk/letters/story/0,,2120896,00.html
%
% The Guardian's reporter and the report's original authors
% should share the blame for this misleading comparison.
\index{nuclear power!station!build rate}
\index{myth!nuclear power build rate}
A more honest presentation
would have kept the comparison on a per-planet basis.
\ind{France} has 59 of the world's 429 operating nuclear reactors,
% The world has 429 nuclear reactors generating 370\,GW.
so it's plausible that the highest
rate of reactor building for the whole planet
was something like ten times France's, that is, 34 new reactors per year.
And the required rate (3000 new reactors over 60 years) is
50 new reactors per year.
So the assertion that ``civil nuclear construction
on this scale is a pipe dream, and
completely unfeasible'' is \ind{poppycock}.
Yes, it's a big construction rate, but it's in the same ballpark as
historical construction rates.
%% http://www.iaea.org/cgi-bin/db.page.pl/pris.reaopag.htm
%% current set of nukes
%% http://www.world-nuclear.org/info/reactors.html
How reasonable is my assertion that the world's
maximum historical construction rate must have been about
34 new nuclear reactors per year?
Let's look at the data.
\marginfig{
\begin{center}
%% see W.gnu
\mbox{\ \epsfxsize=50mm\epsfbox{../../refs/nuclear/World.eps}} \\[0.16in]
\end{center}
\caption[a]{Graph of the total nuclear power in the world that
was built since 1967 and that is still operational today.
The world construction rate peaked at 30\,GW of nuclear power
per year in 1984.
}
\label{fig.worldnuke}
}%
\Figref{fig.worldnuke} shows the power of the world's nuclear fleet
as a function of time, showing only the power stations still operational
in 2007.
The rate of new build was biggest in 1984, and had a value of
(drum-roll please\ldots) about 30\,GW per year -- about 30 1-GW
reactors. So there!
}
% about coal ash
% http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html
%\input{uranium.tex} nothing there now
\section{What about nuclear fusion?}
\myquote{We say that we will put the sun into a box. The idea is pretty. The problem is, we don't know how to make the box.}{S\'ebastien Balibar, Director of Research, CNRS}
% \section{Fusion}
% I was reluctant to include fusion power, since it
% is so speculative and experimental.
\noindent
Fusion
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm%
\lowres%
{\epsfbox{../../images/JETinsideS.eps}}%
{\epsfbox{../../images/JETinside.eps}}%
}\\
\end{tabular} \\
\end{center}
\caption[a]{The inside of an experimental fusion reactor.
Split image showing
%interior view of
the JET vacuum vessel with a superimposed image
of a JET plasma, taken with an ordinary TV camera.
% in the visible spectrum.
Photo: EFDA-JET\@.
% www.jet.efda.org
}
}%
% used with permission from the website
power is speculative and experimental.\index{nuclear!reactor!fusion}
I think it is reckless to assume that the fusion problem
{\em{will}\/} be cracked, but I'm happy to estimate how much
power fusion could deliver, {\em{if}\/}
the problem is cracked.
% But the energies of the intended fusion reactions
% are well known, so it's quite easy to work out
% how much energy fusion could deliver, {\em{if}\/}
% the problems are cracked.
%% refer page 75 hodgson
The two fusion reactions that are considered the
most promising are:
\begin{description}
\item[the DT reaction,] which fuses deuterium with tritium,
% (obtained from lithium),
making helium; and
\item[the DD reaction,] which fuses deuterium with deuterium.
\end{description}
Deuterium, a naturally occurring heavy isotope of hydrogen, can
be obtained from seawater; tritium, a heavier isotope of hydrogen,
isn't found in large quantities naturally (because it has a half-life of only 12 years)
but it can be manufactured from lithium.
\ind{ITER} is an international project to figure out how to make
a steadily-working \ind{fusion reactor}.
The ITER prototype will use the \ind{DT} reaction. DT is preferred
over \ind{DD}, because the DT reaction yields more
energy and because it requires a temperature of ``only''
100 million\degreesC\ to get it going, whereas
the DD reaction requires 300 million\degreesC.
(The maximum temperature in the sun is 15 million\degreesC.)
%% The material in the core is very dense, about 160 times as dense as water is on Earth.
%% iter will have 10**20 particles per m**3
Let's fantasize, and assume that the ITER project is successful.
What sustainable power could fusion then deliver? Power stations
using the DT reaction, fuelled by lithium, will run out of juice when
the lithium runs out. Before that time, hopefully the second
installment of the fantasy will have arrived: fusion reactors using
deuterium alone.
I'll call these two fantasy energy sources ``\ind{lithium fusion}'' and
``\ind{deuterium fusion},'' naming them after the principal fuel we'd
worry about in each case. Let's now estimate how much energy each of
these sources could deliver.
\subsection{Lithium fusion}
% net plant efficiency 0.38 is mentioned in a tokamak paper
% 100 Kg of deuterium and 3 tons of natural lithium to operate for a whole year, generating about 7 billion kWh
% that's 2333 kWh/g
% try http://www3.interscience.wiley.com/cgi-bin/abstract/109069971/ABSTRACT?CRETRY=1&SRETRY=0 ???
% 3.2g natural lithium -> 1MWh 310kWh/g www.springerlink.com/index/35470543RJ8T2GK1.pdf
%Estimated reserves of natural
%Li are 11 million tons in known ore deposits in the
%earth and 200 billion tons dissolved in seawater
%[18d], equivalent to about $9 \times 10^3$ and $1.7 \times 10^8$ TWyr.
%
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}cc}
% {\small\sc Consumption}& {\small\sc Production}\\
\mbox{\epsfbox{metapost/stacks.349}} & \\
\end{tabular}
\end{center}
% }{
\caption[a]{
%% Chapter \protect\ref{ch.fusion}'s conclusion:
Lithium-based fusion, if used fairly and ``sustainably,''
could match our current levels of consumption.
Mined lithium would deliver 10\,kWh/d
per person for 1000 years;
lithium extracted from seawater could deliver 105\,kWh/d per person
for over a million years.
}
% \end{figure}
}%
%% www.dnpm.gov.br/enportal/assets/galeriadocumento/SumarioMineral2002en/Litio.doc -
World lithium reserves are estimated to be 9.5 million tons in ore deposits.\label{brazil}
%% 9.52 million tons.
%% of lithium oxide-contained.
% The main lithium sources are found in
% Bolivia (56.6\%), Chile (31.4\%) and the United States (4.3\%).
If all these reserves were devoted to fusion over 1000 years,
the power delivered would be \OliveGreen{10\,kWh/d per person}.\nlabel{lithiumFu}
% GRAMS kWh/g people 1000 yrs
% pr 11e12 * 3400 / 6e9 / 365.25e3
% pr 9.5e12 * 2300 / 6e9 / 365.25e3
% 17.0659365731234
%{\bf If I take 11 M tons and 3400 \kWhe per g of lithium,
%I get 17\,\kWhe/d per person for 1000 years.}
%% most lithium is currently recovered from brine pools
%% China may emerge as a significant producer of brine-based lithium carbonate towards the end of this decade. Potential capacity of up to 45,000 tonnes per year could come on-stream if projects in Qinghai province and Tibet proceed.[
%% http://www.fusie-energie.nl/artikelen/ongena.pdf
There's another source for
\ind{lithium}: \ind{seawater}, where
lithium has a concentration of 0.17\,ppm.\nlabel{lithiumSea}
To produce lithium at a rate of
% 10$^{8}$\,kg/y
100 million kg per year
from seawater is estimated to
have an energy requirement of 2.5\,\kWhe\ per gram of lithium.
If the fusion reactors give back 2300\,\kWhe\ per gram of \ind{lithium},
% pr 3400 * 1e11 / 365.25/6e9
% 155.144877937486
%
% pr 2300 * 1e11 / 365.25/6e9
the power thus delivered would be \OliveGreen{105\,kWh/d per person} (assuming 6 billion
people).
At this rate, the lithium in the oceans would last more than a million years.
% http://www.batteriesdigest.com/lithium_materials.htm
\subsection{Deuterium fusion}
If we imagine that scientists and engineers crack the problem
of getting the DD reaction going, we have some very good news.
There's 33\,g of deuterium in every ton of water,
and the energy that would be released from fusing
just one gram of deuterium is a mind-boggling
100\,000\,kWh.
% cf 10kWh from 1000g of petrol, ie 0.01kWh per g. This is
% 4.6e13 tons of D in oceans.
% Energy density: 350e15J per ton of D.
% 9.7222e+04
% 100\,000\,kWh per g of D.
% 3200\,kWh per litre of ordinary water.
Bearing in mind that the mass of the oceans is
% 0.23\,km$^3$ per person,
230 million tons per person,
we can deduce that there's enough deuterium to
supply every person in a
ten-fold increased world population with a power of
30\,000\,kWh per day (that's more than 100 times the average
American consumption) for 1 million years (\figref{fig.DD}).
% we can deduce that even if the world population increased
% ten fold, and every person had a power consumption of
% 30\,000\,kWh per person per day,
% fusion would still last 1 million years (\figref{fig.DD}).
% \citep{Ongena}
% Using the DD reaction (page 75 of Hodgson)
% Need to get these numbers straight...
% I think these are wrong (if I trust Ongena)
%Energy of 18\,g of D$_2$O is 117\,MJ (32\,kWh).
%So 1 litre of D$_2$O is 1800\,kWh.
% Deuterium is one part in 6000 in water.
% Deuterium represents approximately 0.015\% of hydrogen\index{hydrogen!for fusion}
% in water.
% The conventional method of concentrating deuterium in water uses isotopic exchange in hydrogen sulphide gas, although more advanced techniques are being developed. Separation of different isotopes of hydrogen can also be done using gas chromatography and cryogenic distillation, which use the differences in physical properties to separate the isotopes.
% http://www.fusion.org.uk/faq/answers.html
% From Ongena:
% DD reaction yields 7.3\,MeV total (2.7$\times 10^{-12}$\,J)
%Volume of oceans = 1.37 billion km$^3$,
%which is 0.23 km$^3$ each.
% 1km**3 in litres : 1e12
% volume of ocean each = 0.23 km$^3$
% number of years if use all at 300 kWh/d
% 0.23e12 * 1800 / 300 / 365.25
% ans = 3.7782e+9
% 4 b yr.
% If assume can only suck down 1%, and that the process is 10% efficient,
% still get 4 M y.
% Imagine that we extract one quarter of the deuterium from the oceans.
%((((((0.23 (km ** 3)) / (1 litre)) * 7.3 MeV * Avogadro's number) / 6 000) * 1 000) / 18) / ((300 kWh) * 365) = 3.80514862 × $10^9$ years
%((((0.23 (km ** 3)) / (18 (cm ** 3))) * 7.3 MeV * Avogadro's number) / 6 000) / ((300 kWh) * 365) = 3.80514862 × 109
% At 300\,kWh per person per day, and 6 billion people,
% so the area to aim for is 300 000 000 kWh / d / p (for 1000 y)
% Which can be made by taking something 150 high and 6x wide (900)
% then scaling it up by 1000/3 in each dimension
% or go for 1e6 years?
\begin{figure}
\figuremargin{
\begin{center}
\begin{tabular}{@{}cc}
%% {\small\sc Consumption}& {\small\sc Production}\\
\mbox{\epsfbox{metapost/stacks.230}} & \\
%% {\mbox{\epsfbox{crosspad/cars3.ps}}} & ? \\
\end{tabular}
\end{center}
}{
\caption[a]{Deuterium-based fusion, if it is achievable,
offers plentiful sustainable energy for millions of years.
This diagram's scale is shrunk ten-fold in each dimension so as to fit
fusion's potential contribution on the page. The red and green stacks
from \figref{fig.halftime} are shown to the same scale, for comparison.
}\label{fig.DD}
}
\end{figure}
%How is deuterium obtained from water?
% The conventional method of concentrating deuterium in water uses isotopic exchange in hydrogen sulphide gas, although more advanced techniques are being developed. Separation of different isotopes of hydrogen can also be done using gas chromatography and cryogenic distillation, which use the differences in physical properties to separate the isotopes.
% http://www.fusion.org.uk/faq/answers.html
% Deuterium fusion has
\small
%\beginfullpagewidth
\section{Notes and further reading}
\beforenotelist
\begin{widenotelist}
\item[page no.]
\item[\npageref{fig.nuc}] {\nqs{\Figref{fig.nu}}}.
Source: World Nuclear Association
\tinyurl{5qntkb}{http://www.world-nuclear.org/info/reactors.htm}.
The total capacity of operable nuclear
% 65000 / 372 is 175 tonnes per GWy
% 2608e9 kWh in ( GW year) is 298 GW y
% 65000 / 298 is 218 tonnes per GWy
reactors is 372\,\GWe, using 65\,000 \tonnes\ of
uranium per year. The USA has 99\,GW,
France 63.5\,GW, Japan 47.6\,GW,
Russia 22\,GW, Germany 20\,GW, South Korea 17.5\,GW,
Ukraine 13\,GW,
Canada 12.6\,GW, and UK 11\,GW\@.
In 2007 all the world's reactors generated 2608\,TWh of electricity,
which is an average of 300\,GW, or \OliveGreen{1.2\,kWh per day per person}.
\item[\npageref{pFast60}] {\nqs{Fast breeder reactors
obtain 60 times as much
energy from the uranium.}}
Source:
\myurlb{www.world-nuclear.org/info/inf98.html}{http://www.world-nuclear.org/info/inf98.html}.
\ind{Japan} currently leads the development of
fast breeder reactors.
%% also Such a reactor, supplied with natural or depleted uranium for its "fertile blanket", can be operated so that each tonne of ore yields 60 times more energy than in a conventional reactor.
%% http://www.world-nuclear.org/info/inf75.html
\item[\npageref{p162}] {\nqs{A once-through
{one-gigawatt} nuclear power station uses {162 tons per year of uranium}}}.
\par
Source:
\myurlb{www.world- nuclear.org/info/inf03.html}{http://www.world- nuclear.org/info/inf03.html}.
A 1\,\GWe\ station with a thermal efficiency of 33\%
running at a load factor of 83\%
%% I think 85% is widely assumed see 7450 GWh per year on google
has the following upstream footprint:
mining -- 16\,600 \tonnes\ of 1\%-uranium ore;
milling -- 191\,t of uranium oxide
% concentrate
(containing 162\,t of natural uranium);
enrichment and fuel fabrication -- 22.4\,t of uranium oxide
(containing 20\,t of enriched uranium).
The enrichment requires 115\,000\,\ind{SWU}; see \pref{pSWU}
for the energy cost of SWU (separative work units).
%% conversion rate
%% 8640e6 kWh 195 t natural U
%% that is 0.0226 g per kWh
%% 8640e6 / 195000000
%% 44.3kWh per gramme
%% 3.5e6 / 195 * 8640e6 / 6e9 / 1000 / 365.25
%% 27.0e6 / 195 * 8640e6 / 6e9 / 1000 / 365.25
\item[\npageref{UEstimate}]
{\nqs{it's been estimated that the low-grade uranium resource
is more than 1000 times greater than the 22 million \tonnes\ we just assumed}}.
\citet{UEstimate} estimate that the resource
of uranium in concentrations of 30\,ppm or more is
$3 \times 10^{10}$ \tonnes.
% down to uranium concentrations of 10 parts per million is
% $6 \times 10^{11}$ \tonnes.
(The average ore grade processed in South Africa in 1985 and 1990 was 150\,ppm.
Phosphates typically average 100\,ppm.)
% http://tin.er.usgs.gov/
%Low grades can be used.
% page 129 of
% http://books.google.com/books?id=HIT1o985uKYC&printsec=frontcover#PPA129,M1
%Recovery from phosphates is possible, and was done before 1998,
%and will be economic at prices above \$120/kgU.
%Phosphates: 7\,Mt reported of which 6.5\,Mt in Morocco.
Here's what the World Nuclear Association said on the topic
of uranium reserves in June 2008:
``From time to time concerns are raised that the known resources might
be insufficient when judged as a multiple of present rate of use. But
this is the \index{fallacy!Limits to Growth}\ind{Limits to Growth} fallacy, \ldots\
which takes no account of the very limited
nature of the knowledge we have at any time of what is actually in the
Earth's crust. Our knowledge of geology is such that we can be
confident that identified resources of metal minerals are a small
fraction of what is there.
``Measured resources of uranium, the amount known to be economically
recoverable from orebodies, are \ldots\ dependent on the intensity of
past exploration effort, and are basically a statement about what is
known rather than what is there in the Earth's crust.
``The world's present measured resources of uranium (5.5\,Mt)
\ldots\ are enough to last for over 80 years. This
represents a higher level of assured resources than is normal for most
minerals. Further exploration and higher prices will certainly, on
the basis of present geological knowledge, yield further resources as
present ones are used up.''
``Economically rational players will only invest in finding these new
reserves when they are most confident of gaining a return from them,
which usually requires positive price messages caused by undersupply
trends. If the economic system is working correctly and maximizing
capital efficiency, there should never be more than a few decades of
any resource commodity in reserves at any point in time.''
[Exploration has a cost; exploring for uranium, for example,
has had a cost of \$1--\$1.50 per kg of uranium (\$3.4/MJ), which
is 2\% of the spot price of \$78/kgU; in contrast,
the finding costs of crude oil have averaged around \$6/barrel
(\$1050/MJ) (12\% of the spot price)
over at least the past three decades.]
%http://www.world-nuclear.org/info/inf75.html
``Unlike the metals which have been in demand for centuries,
society has barely begun to utilize uranium.
There has been only one cycle of exploration-discovery-production, driven in large part by late 1970s price peaks.
``It is premature to speak about long-term uranium scarcity when the
entire nuclear industry is so young that only one cycle of resource
replenishment has been required.''
\myurlb{www.world- nuclear.org/info/inf75.html}{http://www.world-nuclear.org/info/inf75.html}
Further reading: \cite{HerringUTh,PriceNuclear,Breeder1983Cohen}.
%http://books.google.com/books?id=HIT1o985uKYC
The IPCC, citing the OECD, project that at the 2004 utilization levels,
the uranium in conventional resources and phosphates would last
670 years in once-through reactors,
20\,000 years in fast reactors with plutonium recycling,
and 160\,000\,years in fast reactors recycling uranium and
all actinides
\citep{IPCCwg3ch4}.
% page 21 of ch4 doc that's 30x bigger and 240x bigger respectively
\item[\npageref{pagejaps}]
{\nqs{Japanese researchers have found a technique for
extracting \index{uranium!extraction from seawater}\index{seawater!uranium extraction}uranium
from seawater}}.
The price estimate of \$100 per kg is from \citet{SekoEtAl}
and
\tinyurl{y3wnzr}{http://npc.sarov.ru/english/digest/132004/appendix8.html};
the estimate of \$300 per kg is from \citet[p130]{RedBook40}.
% page 131
% p130
% cost $300 per kg U.
% thousands of tons per year possible
% Summary of Japanese research into extracting uranium from
% seawater -- from
The uranium extraction technique involves dunking
tissue in the ocean for a couple of months;
the tissue is made of polymer fibres that are rendered sticky
by irradiating them before they are dunked;
the sticky fibres collect uranium to the tune of 2\,g of uranium
per kilogram of fibre.
% Even at \$200/kg, uranium from
% seawater would be cheaper than reprocessing spent fuel
% and recycling plutonium and uranium. uranium at \$200/kg
% would increase the cost of nuclear energy by about 0.4
% \cents\ per kWh.
% Have to process 354\,000 \tonnes\ of seawater to produce one kg U.
\item[\npageref{pUextCool}]
{\nqs{The expense of uranium extraction could be reduced by combining
it with another use of \ind{seawater} -- for example, power-station cooling.}}
The\index{island!nuclear}\index{nuclear!hydrogen production}
idea of a nuclear-powered island producing hydrogen\index{hydrogen!production by nuclear power}
was floated by C.\ Marchetti.\index{Marchetti, C.}\index{uranium!extraction from seawater}
Breeder reactors would
be cooled by seawater and would extract uranium from
the cooling water at a rate of 600\,t uranium per
500\,000\,Mt of seawater.
%% reference?
% For a number that differs by 2, Source: \cite[p. 131]{RedBook40}
% page 131
% Have to process 354\,000 \tonnes\ of of seawater to produce one kg U.
% which says you need 212000Mt instead of 500000000000
% p130
% cost $300 per kg U.
% thousands of tons per year possible
\item[\npageref{pThoriumR}]
{\nqs{Thorium reactors deliver $3.6\times10^9$\,kWh of heat per ton of thorium}}.
Source: \myurlb{www.world-nuclear.org/info/inf62.html}{http://www.world-nuclear.org/info/inf62.html}.
There remains scope for advancement in
thorium reactors, so this figure could be bumped up in the
future.
% rubbia claims 100 GW d thermal per t which is 2.4 e9 kWh per t
\item[\npageref{pRubbiaEt}]
{\nqs{An alternative nuclear reactor for \ind{thorium}, the ``energy amplifier''\ldots
}}
See \citet{RubbiaEtAl2},
% A webpage about the Energy Amplifier reactor
\myurlb{web.ift.uib.no/~lillestol/Energy_Web/EA.html}{http://web.ift.uib.no/~lillestol/Energy_Web/EA.html},
%http://web.ift.uib.no/~lillestol/Energy_Web/EA.html
%
% Further reading on Thorium:
%% http://web.ift.uib.no/~lillestol/Energy_Web/Energy_and%20Thorium.html
%% http://web.ift.uib.no/~lillestol/Energy_Web/Energy_and%20Thorium.html
%
%% more notes on EA
%`Energy Amplifier' (also known as `Accelerator Driven System'),
% a description for non-specialists:
{\tinyurl{32t5zt}{http://web.ift.uib.no/~lillestol/Energy_Web/EA.html}},
%
% tinyurl for Rubbia et al document:
\tinyurl{2qr3yr}{http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-0210391}, \tinyurl{ynk54y}{http://doc.cern.ch//archive/electronic/other/generic/public/cer-0210391.pdf}.
% 2qr3yr
%http://documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-0210391
% ynk54y
%http://doc.cern.ch//archive/electronic/other/generic/public/cer-0210391.pdf
%%%% notes cut to _uranium.tex
%% including CO2 emissions numbers
\item[\npageref{pMonazite}]
{\nqs{World thorium resources in monazite}.}
source: US Geological Survey, Mineral Commodity Summaries, January 1999.
\tinyurl{yl7tkm}{http://minerals.usgs.gov/minerals/pubs/mcs/1999/mcs99.pdf}
%% http://minerals.usgs.gov/minerals/pubs/mcs/1999/mcs99.pdf
Quoted in
UIC Nuclear Issues Briefing Paper \#67
November 2004.
% {http://minerals.usgs.gov/minerals/pubs/mcs/1999/mcs99.pdf}
``Other ore minerals with higher thorium
contents, such as thorite, would be more likely sources if demand significantly increased.''
%% Thorite is the most common thorium mineral.
%% http://www.galleries.com/minerals/silicate/thorite/thorite.htm
%% http://www.lenntech.com/Periodic-chart-elements/Th-en.htm
%% Because thorium oxide is highly insoluble, very little of this element circulates through the environment.
%% Known reserves exceed 3 million \tonnes.
{\tinyurl{yju4a4}{http://www.uic.com.au/nip67.htm}} omits the figure for Turkey,
which is found here:
%% http://taylorandfrancis.metapress.com/index/W7241163J23386MG.pdf
\tinyurl{yeyr7z}{http://taylorandfrancis.metapress.com/index/W7241163J23386MG.pdf}.
\item[\npageref{NukTot}]
{\nqs{The nuclear
industry sold everyone in the UK 4\,kWh/d for about 25 years}.}
The total generated to 2006 was about
2200\,TWh.
% source: Salter 2zazd7
% \tinyurl{2zazd7}
Source: Stephen Salter's Energy Review for the Scottish National Party.
\item[\npageref{pCleanup}]
{\nqs{The \ind{nuclear decommissioning authority} has an annual budget
of \pounds2 {{billion}}}.}
In fact, this clean-up \index{nuclear clean-up costs}budget
seems to rise and rise.
The latest figure for the total cost of decommissioning is
\pounds73\,billion.\index{billion!nuclear decommissioning}\index{cost!nuclear decommissioning}
\myurlb{news.bbc.co.uk/1/hi/uk/7215688.stm}{http://news.bbc.co.uk/1/hi/uk/7215688.stm}
\item[\npageref{pThorp}]
{\nqs{The criticism of the Chief Inspector of Nuclear Installations was
withering\ldots}}
\citep{Thorp}.
\item[\npageref{pRisk}]
{\nqs{Nuclear power is not infinitely dangerous. It's just dangerous.}}
Further reading on risk: \cite{KammenRisk}.
\item[\npageref{pCoalNu}]
%{\nqs{Coal power stations expose the public
% to nuclear radiation.}}
{\nqs{People in America living near coal-fired power stations
are exposed to higher radiation doses than those
living near nuclear power plants.}}
Source: \citet{CoalIsNuke}.
% people in America living near coal-fired power stations
% are exposed to higher radiation doses than those
% living near nuclear power plants.
Uranium and thorium have concentrations\index{coal!contains uranium and thorium}
of roughly 1\,ppm and 2\,ppm respectively in coal.\index{uranium!in coal}\index{thorium!in coal}
\nocite{Hodgson99}\nocite{Nuttall04}
Further reading:
\myurlb{gabe.web.psi.ch/research/ra/ra_res.html}{http://gabe.web.psi.ch/research/ra/ra_res.html}, \par
\myurlb{www.physics.ohio-state.edu/~wilkins/energy/Companion/E20.12.pdf.xpdf}{http://www.physics.ohio-state.edu/~wilkins/energy/Companion/E20.12.pdf.xpdf}.
\item[\npageref{pWN}]
{\nqs{Nuclear power and wind power have the lowest death rates.}}
See also \citet{StatsNuke}.
These death rates are from studies that are predicting the future.
We can also look in the past.
In Britain, nuclear power has generated 200\,GWy of electricity,
and the nuclear industry has had 1 fatality,
a worker who died at Chapelcross in 1978\nlabel{pOneDead}
% Nuclear in the UK: 200\,GWy, zero direct public deaths from radiation,
% how many statistical deaths?
% One worker died at Chapelcross in 1978.
% http://www.publications.parliament.uk/pa/cm199900/cmhansrd/vo000505/text/00505w05.htm
% wind in the UK: 3GWy; world wind, roughly 50GWy.
\tinyurl{4f2ekz}{http://www.publications.parliament.uk/pa/cm199900/cmhansrd/vo000505/text/00505w05.htm}.
One death per 200\,GWy is an impressively low death rate
compared with the fossil fuel industry.
Worldwide, the nuclear-power historical death rate is hard to estimate.
The Three Mile Island meltdown killed no-one, and the associated
leaks are estimated to have perhaps killed one person in the time
since the accident.
The accident at
Chernobyl\label{pChernobyl} first killed 62 who died directly from
exposure, and 15 local people who died later of thyroid cancer;
% 6.7 \tonnes\ of radioactive junk released.
% 62 direct deaths.
% 4000 local cases of thyroid cancer of whom just 15 died.
% An estimate of 9000 total deaths worldwide.
% (Cancer already causes 25\% of deaths in Europe, so an extra 9000 deaths is
% a small change in this percentage.)
it's estimated that nearby, another 4000 died of cancer,
and that worldwide, about 5000 people (among 7 million who were exposed
to fallout) died of cancer because of
Chernobyl \citep{Chernobyl}; but these deaths are impossible to detect because cancers,
many of them caused by natural nuclear radiation,
already cause 25\% of deaths in Europe.
% Chernobyl increased the
% chance of getting fatal cancer by a tiny fraction -- from 25\% to 25.05\%,
% perhaps.
% europe is 500e6 people, who die at a rate of 1/70 per year
% cancer death rate is 500e6/70/4 per year
% assume theyChernies all died during 20 years, then the
% cancer death rate in that period went up from 500e6/70 *20/4 = 36million
% to that plus 9000
% \item[\npageref{pChernobyl}] {\nqs{Chernobyl}}.
% If this total, 9000 deaths, is correct, then
One way to estimate a global death rate from nuclear power worldwide is
to divide this estimate of Chernobyl's death-toll (9000 deaths) by the
cumulative output of nuclear power from 1969 to 1996, which
was 3685\,GWy. This gives a death rate of 2.4 deaths per GWy.
% Nature April 20 2006 page 984 Review articles.
%An estimate of 9000 total deaths worldwide,
%4000 of whom are among a set of 600\,000 people who were exposed
%to a significant amount of radiation, giving 4/600 chance of death;
%and the other 5000 are among a set of 6.8M others further away, exposed to 7 millisieverts,
%which is comparable to total natural yearly dose.
%Cancer already causes 25\% of deaths in Europe.
As for deaths attributed to wind,
% Wind:
Caithness Windfarm Information Forum
\myurlb{www.caithnesswindfarms.co.uk}{http://www.caithnesswindfarms.co.uk/}
list 49 fatalities worldwide
from 1970 to 2007 (35 wind industry workers and 14 members of the public).
%Wind Energy -- The Breath of Life or the
%Kiss of Death: Contemporary Wind Mortality Rates, by Paul Gipe Also
%Windpower Monthly December 1997 and
%February 1998
% http://www.wind-works.org/articles/BreathLife.html
% I reported in Wind Energy comes of Age a mortality rate of 0.27 deaths per TWh. However, the mortality rate was higher than I reported then. I had missed several accidents that I learned of later.
In 2007, Paul Gipe listed 34 deaths total worldwide
[\myurlb{www.wind-works.org/articles/BreathLife.html}{http://www.wind-works.org/articles/BreathLife.html}].
In the mid-1990s the mortality rate associated with wind power was
% 0.4 per TWh (
3.5 deaths per GWy.
According to Paul Gipe, the worldwide mortality rate of wind power dropped to
% 0.15 deaths per TWh
1.3 deaths per GWy
by the end of 2000.
% DE 1111 (including driver distraction, 3 cases)
% USA 11111111111111111111 (inc 4 in plane that flew into wind t)
% SWED 1
% China 1
% UK
% Denmark 12
% NL 11
% Aus 11
So the historical death rates of both nuclear power and wind are
higher than the predicted future death rates.
%\item[\npageref{pOneDead}]
% {\nqs{In Britain, the nuclear industry has had 1 fatality.}}
\item[\npageref{pNukeCOO}]
{\nqs{The steel and concrete
in a 1\,GW nuclear power station
have a carbon footprint of roughly
300\,000\,\tCOO}.
}
% How much concrete and steel
A 1\,GW nuclear power station contains
% ? The Nuclear Energy Institute say
% (\myurl{http://www.nei.org/index.asp?catnum=3&catid=1525}) DEAD URL
% 400\,000 cubic yards
520\,000\,m$^3$ of concrete (1.2 million \tons) and
% 60\,000 tons (
67\,000 \tonnes\ of
steel
%in a 1\,GW nuclear power station.
\tinyurl{2k8y7o}{http://www.nei.org/resourcesandstats/}.
% \COO\ from concrete upstream footprint is 1/50 by mass.
% according to http://www.cmpbs.org/publications/T1.2-AD4.5-Up_Gbl_wrm.pdf
% this is lower than below?
%
%How much \COO\ is produced when making 520\,000 cubic meters of concrete?
% That depends on the kind of concrete. There are different types and different figures. One way --
% Take the density of concrete (2300 kg/m$^3$),
% from the Physics Factbook),
% the \COO\
% to make cement (0.8\,kg\,\COO/kg cement), the cement
% in concrete (10\% from \url{cement.org}).
% 0.08 kg per kg
% cf 0.020 t per t ??
% (A life-cycle analysis gives 43--240\,kg \COO\ per \tonne\ of concrete, depending
% on the type of concrete, with
Assuming
% 100\,kg\,\COO\ per \tonne\ of concrete
240\,kg\,\COO\ per m$^3$ of concrete
\tinyurl{3pvf4j}{http://www.sustainableconcrete.org.uk/main.asp?page=210},
the concrete's footprint is
% same document suggests 240 kg CO2 per m**3
% This makes a figure of
around 100\,000\,\tCOO\@.
% \ for one nuclear plant.
% Alternatively, the Danish Technology Institute says
%(\myurl{http://www.danishtechnology.dk/})
% that a cubic meter of concrete requires the production of 100\,kg
%\COO, giving us 50\,000 t\COO\ for the concrete in
%one nuclear power station.
% \COO\ from steel
From
% How much \COO\ is produced in making 67\,000 \tonnes\ of steel?
Blue Scope Steel \tinyurl{4r7zpg}{http://csereport2005.bluescopesteel.com/},
%claim they put out 14.5 million \tonnes\ of \COO\ equivalent gases in
%2004/2005 to produce 5.72 million \tonnes\ of steel product, which
% 14.5e6/5.72e6 2.53
the footprint of steel is about
%suggests around 2.5
2.5 tons of \COO\ per ton of steel.
% Azom.com materials suggests around 2 \tonnes\ of \COO\ per \tonne\ of
% steel, and Tata Steel claim
%(\tinyurl{36y2e4}{http://www.tatasteel.com/webzine/tatatech39/page14.htm})
%between 1.2 and 1.9 \tonnes\ of \COO\ per \tonne\ of steel, depending on
%the process.
%
% Taking the largest figure, 3 \tonnes\ of \COO\ for a \tonne\ of steel,
So the 67\,000 \tonnes\ of steel has a
footprint of about 170\,000 \tonnes\ of \COO\@.
%Summing the steel and concrete figures:
%300\,000\,\tCOO\ is associated with the construction of a 1\,GW nuke.
% If we had been conservative, that would have been 100 million kg \COO\@.
\item[\npageref{WasteP}]
{\nqs{Nuclear waste discussion}.}
Sources: \myurlb{www.world-nuclear.org/info/inf04.html}{http://www.world-nuclear.org/info/inf04.html},
\tinyurl{49hcnw}{http://www.ace.mmu.ac.uk/Resources/Fact_Sheets/Key_Stage_4/Waste/pdf/02.pdf},
\tinyurl{3kduo7}{http://www.esrcsocietytoday.ac.uk/ESRCInfoCentre/facts/UK/index29.aspx?ComponentId=7104&SourcePageId=18130}.
{\nqs{New nuclear waste compared with old.}}
\cite{CORWM}.
% from http://www.npower.com/web/about_npower/our_responsibility/where_our_electricity_comes_from/index.htm
% The radioactive waste, being fuel burnt in the reactor to be subsequently discharged as spent fuel, is 0.00145 grams per kWh.
% a lifetime of 4kWh/d is 0.00145 * 4 * 365 * 70
% = 148g.
\item[\npageref{brazil}]
{\nqs{World lithium reserves are estimated as 9.5 million tons}.}
The main lithium sources are found in\label{brazilNot}
Bolivia (56.6\%), Chile (31.4\%) and the USA (4.3\%).
\myurlb{www.dnpm.gov.br}{http://www.dnpm.gov.br/}
% \myurl{www.dnpm.gov.br}
%{\sc World lithium reserves are estimated to be 9.5 million tons in ore deposits.}
%% 9.52 million tons.
%% of lithium oxide-contained.
\item[\npageref{lithiumSea}]% Ocean lithium.
{\nqs{There's another source for
\ind{lithium}: \ind{seawater}\ldots}}
Several extraction techniques have been investigated
\citep{Lithium75,Tsuruta,Lithium40}.
% The maximum uptake of lithium from seawater is 40 mg/g
% \citep{Lithium40}.
%% http://www.cheric.org/research/tech/periodicals/vol_view.php?seq=342188
% The extractable amount in seawater is roughly 10\,000 times greater.
%% http://en.wikipedia.org/wiki/Lithium says
% Lithium in seawater: 2.5 x 10$^{14}$\,kg.
% Lithium in seawater: 2.5 x 10$^{5}$\,Mt.
\item[\npageref{lithiumFu}]
{\nqs{Fusion power from lithium reserves.}}
The energy density of natural lithium is about
% $27 \times 10^{15}$\,J/ton
7500\,kWh per gram \citep{Ongena}.
There's considerable variation among the estimates of
how efficiently fusion reactors would turn this into electricity,
ranging from 310\,\kWhe/g \citep{Eckhartt1995}
to 3400\,\kWhe/g of natural lithium
\citep{Lithium75}. I've assumed 2300\,\kWhe/g, based on this
widely quoted summary figure:
``A 1\,GW fusion plant will use about 100\,kg of deuterium
and 3 \tonnes\ of natural lithium per year,
generating about 7 billion kWh.''
%% http://www.greencarcongress.com/2006/11/green_light_for.html
\tinyurl{69vt8r}{http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=7200593},
\tinyurl{6oby22}{http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=6773271&query_id=0},
\tinyurl{63l2lp}{http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2002/124/i18/abs/ja003472m.html}.
%http://www.chemistry.org/portal/a/c/s/1/acsdisplay.html?DOC=heartcut%5Carchive%5C0610_heartcut.html (near the bottom)
\item[Further reading about fission:]
\citet{Hodgson99}, \citet{Nuttall04},
\citet{WEAch5},
\citet{WEAch8}.
Uranium Information Center --
\myurlb{www.uic.com.au}{http://www.uic.com.au/}.
\myurlb{www.world-nuclear.org}{http://www.world-nuclear.org/},
%\myurl{http://www.world-nuclear.org/co2&nfc.htm}
%Energy cost of full uranium cycle, broken down in detail
% here:
\tinyurl{wnchw}{http://www.feasta.org/documents/wells/contents.html?one/horelacy.html}.
On costs: \cite{Zaleski}.
On waste repositories: \tinyurl{shrln}{http://www.enviros.com/vrepository/}.
% Site for unbiased information on waste repositories.
On breeder reactors and thorium: \myurlb{www.energyfromthorium.com}{http://www.energyfromthorium.com/}.
% http://en.wikipedia.org/wiki/Molten_salt_reactor
% http://en.wikipedia.org/wiki/Integral_fast_reactor
\item[Further reading about fusion:]
\myurlb{www.fusion.org.uk}{http://www.fusion.org.uk/},
%A reader writes:
%``The most promising looking fusion project appears to be the IECF approach.
%While not yet `proven', it appears to offer the shortest implementation
%time. You can find a lot of background on it here:
\myurlb{www.askmar.com/Fusion.html}{http://www.askmar.com/Fusion.html}.
\end{widenotelist}
\normalsize
% \ENDfullpagewidth
% \subsection{Additional material for reprocessing...}
% fatal dose of radiation is 400 REM which is 400 roentgen for one hour
\gset\chapter{\gcol{Living on other countries' renewables?}}
\label{ch.international}
\label{international}
%\input{area.tex}
\myquote{
Whether the Mediterranean becomes an area of cooperation or confrontation in the 21st
century will be of strategic importance to our common security.
% Intensive international collaboration is a main requisite for success.
% page 9 of the german document TREC
}{
\index{Fischer, Joschka}Joschka Fischer, German Foreign Minister, February 2004
}
%\end{quote}
\noindent
We've found that it's hard to get off fossil fuels by living on
our own renewables. Nuclear has its problems too. So what else can we do?
Well, how about living on someone else's renewables?
(Not that we have any entitlement to someone else's renewables, of course,
but perhaps they might be interested in selling them to us.)
Most of the resources for living sustainably are related to land area:
if you want to use solar panels, you need land to put them on;
if you want to grow crops, you need land again.\nocite{Collapse}
\index{Diamond, Jared}Jared Diamond, in his book {\em{Collapse}}, observes that, while many
factors contribute to the collapse of civilizations,
a common feature of all collapses is that the human population
density became too great.
{% FIGURE PACKER
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
Places like Britain and Europe are in a pickle because
they have large population densities, and
all the available renewables are diffuse
-- they have small power per unit area (\tabref{figW2}).
When looking for help,
% The way to solve this pickle is to make partnerships with
we should look to countries that have three
\margintab{
\renewcommand{\W}{\,\Wmm}
\begin{tabular}{@{\,}lr@{\,}} \toprule
\multicolumn{2}{c}{\OliveGreen{\sc{Power per unit land }}}\\
\multicolumn{2}{c}{\OliveGreen{\sc{or water area}}}\\
\midrule
Wind &\OliveGreen{ 2\W} \\
Offshore wind &\OliveGreen{ 3\W} \\
Tidal pools &\OliveGreen{ 3\W} \\
Tidal stream &\OliveGreen{ 6\W} \\
%%% Raw sunshine (UK) &\OliveGreen{50\W} \\
Solar PV panels &\OliveGreen{ 5--20\W} \\
Plants &\OliveGreen{ 0.5\W} \\
Rain-water\\
\ (highlands)
&\OliveGreen{ 0.24\W} \\
Hydroelectric \\
\ facility
&\OliveGreen{ 11\W} \\
% Rain-water (England) &\OliveGreen{ 0.02\W} \\
Solar chimney
%(Spain)
&\OliveGreen{ 0.1\W} \\
% Ocean thermal &\OliveGreen{ 5\W} \\
%\begin{tabular}{@{}l@{}}
\multicolumn{2}{@{\,}l}{\bf Concentrating solar}\hspace*{-0.2mm}\\
\,\,\,\,\ \bf power (desert)
% \\
% \end{tabular}
& {\bf \OliveGreen{ 15\W}} \\
\bottomrule
\end{tabular}
\caption[a]{
% To make a difference, renewable facilities have to be country-sized.
Renewable facilities have to be country-sized
because all renewables are so diffuse.\index{power density!all renewables}
}\label{figW2}
}%
things:
%\begin{enumerate}
\begin{inparaenum}[\itshape a\upshape)]
\item
low population density;
\item
large area; and
\item
a renewable power supply with high power per unit area.
\end{inparaenum}%{enumerate}
\begin{table}[htbp]
\figuremarginb{
{\small
\begin{tabular}{lrrrr} \toprule
Region & Population & Area & Density & Area per \\
& & (km$^2$) & (persons & person \\
& & & per km$^2$) & (m$^2$) \\ \midrule
Libya & 5\,760\,000 & 1\,750\,000 & {{ 3}} & {{ 305\,000}} \\% 3.3
Kazakhstan & 15\,100\,000 & 2\,710\,000 & {{ 6}} & {{ 178\,000}} \\
Saudi Arabia & 26\,400\,000 & 1\,960\,000 & {{ 13}} & {{ 74\,200}} \\
Algeria & 32\,500\,000 & 2\,380\,000 & {{ 14}} & {{ 73\,200}} \\
Sudan & 40\,100\,000 & 2\,500\,000 & {{ 16}} & {{ 62\,300}} \\
\midrule
World & {{6\,440\,000\,000}} & {{148\,000\,000}} & {{ 43}} & {{ 23\,100}} \\
\midrule
Scotland & 5\,050\,000 & 78\,700 & {{ 64}} & {{ 15\,500}} \\
European Union & {{496\,000\,000}} & 4\,330\,000 & {{ 115}} & {{ 8\,720}} \\
% European Union & {{456\,000\,000}} & 3\,970\,000 & {{ 114}} & {{ 8\,710}} \\
Wales & 2\,910\,000 & 20\,700 & {{ 140}} & {{ 7\,110}} \\
{{United Kingdom}}& {{59\,500\,000}} & 244\,000 & {{ 243}} & {{ 4\,110}} \\
{England} & {49\,600\,000} & {130\,000} & {380} & {2\,630} \\ % 2630
\bottomrule \end{tabular}
}
}{
\caption[a]{Some regions, ordered from small to large population density.
See \pref{pDensities}
% and \pageref{countriesD}
for more population densities.\index{population density}
}\label{tabPops}
}
\end{table}
\Tabref{tabPops} highlights some countries that
fit the bill.
\ind{Libya}'s population density, for example,
is 70 times smaller than Britain's,
and its area is 7 times bigger.
Other large, area-rich, countries
% with whom Britain might therefore wish to be
% friendly,
are \ind{Kazakhstan}, \ind{Saudi Arabia}, \ind{Algeria},
and \ind{Sudan}.
%% could include Russia but they don't have sun?
In all these countries, I think the most promising renewable
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/stirling_dish_engine_reducedS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/stirling_dish_engine_reduced.jpg.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{Stirling dish engine.
These beautiful concentrators deliver a power per unit land area of
\powerd{14\,\Wmm}.\index{power density!concentrating solar power}
Photo courtesy of
Stirling Energy Systems.
\myurl{www.stirlingenergy.com}
% and Randy J. Montoya, Sandia National Laboratories.
%% http://www.stirlingenergy.com/newsphotos/RJM54.jpg
%% is a huge image.
}\label{fig.Stirl}% not cited
}%
is solar power, {\dem{concentrating solar power}\/}
in particular,
which uses mirrors or lenses to focus sunlight.
Concentrating solar power stations come in several flavours,
arranging their moving mirrors in various geometries, and
putting various power conversion technologies at the focus --
Stirling engines, pressurized water, or molten salt, for
example -- but they all deliver fairly similar average powers per unit area,
% densities (power per unit land area),
in the ballpark of
\powerd{15\,\Wmm}.\nlabel{pCSP15}
\section{A technology that adds up}
% best link:
% http://www.abb.com/hvdc
% http://www.abb.com/cawp/gad02181/d7779a6f38fcbdc0c1256f9d0046d2b0.aspx
%
% This chapter explores a presumptious idea.
%% , and I apologize for it.
% The presumption is that some countries like Britain might see solve their
% energy problems by getting energy from
%% large renewable facilities
%% in
% other countries. Does this smack of imperialism?
% I'm not saying that the overpopulated countries have any
% entitlement to the other countries' energy. Rather, I hope this
% idea would be explored in a spirit of international cooperation and
% friendship.
%
%% `Solar PV generated power could provide 10,000 times more energy than the world currently uses.'
%% from solarcentury
%% http://www.guardian.co.uk/environment/2006/jun/05/climatechange.climatechange
%% said 800 km * 800 km (they screwed up at one point and said 800 km**2!
%% people often say 0.3% of the sahara
%% http://www.ez2c.de/ml/solar_land_area/ good calcn
%% this one
%% http://www.zukunftstreff.info/science/1-aktuelle-nachrichten/80-europes-dream-of-endless-energy.html
%% talks of 50km * 50km for ``all of europe'' (plus wind)
%% An area 400 x 400 km - a tiny fraction of the N. African desert - covered with solar thermal plants could supply all of the electricity currently used in the EU.
%% http://www.business-magazine.biz/?p=115
``All the world's power could be provided by a square 100\,km
by 100\,km in the Sahara.''
% http://www.environmentalgraffiti.com/sciencetech/03-of-saharan-sun-enough-to-power-europe/1421
% 0.3% of Saharan Sun Enough To Power Europe
Is this true?
Concentrating solar power in deserts delivers an average power per unit land area
of roughly \powerd{15\,\Wmm}.
So, allowing no space for anything else in such a square,
the power delivered would be
% 150000MW
150\,GW\@.
This is {\em{not}\/} the same as current world power consumption.
It's not even near current world {\em{electricity}\/} consumption, which is
2000\,GW\@.
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ABBSolarPowerUnderCons.eps}}}\\
%% also available in higher resolution
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Andasol_I.eps}}}\\
\end{tabular}
\end{center}
\caption[a]{Andasol -- a ``100\,MW'' \index{solar power station}solar power station
%
under construction in \ind{Spain}\index{Andasol}.
% http://www.flagsol.com/andasol_project_RD.htm
%% 2,200 kWh/m^2/y
% http://www.abb.com/cawp/seitp202/0a4536a14acdc2fdc125737f0025a5de.aspx
% 260 M euro. (per plant, and there are two plants?)
Excess thermal energy produced
during the day will\index{salt, heat storage}
be stored
in \index{storage!molten salt}\index{molten salt}\index{liquid salt!energy storage}liquid
salt tanks for up to seven hours,
allowing a continuous and stable supply
of electric power to the grid.
The power station is predicted to produce 350\,GWh per year
(40\,MW).
% It uses some gas also = how much?
% 350e3 / (365.25*24 )*1e6 / 400e4
% 9.98
The \ind{parabolic trough}s\index{concentrating solar power!parabolic trough}
occupy 400\,hectares, so\index{solar power!concentrating!parabolic trough}
the power per unit land area will be \powerd{10\,\Wmm}.
\par
% Andasol I: 50MW from 200ha. collector area: 51ha.
Upper photo: ABB.
Lower photo: IEA SolarPACES\@.
% http://www.notre-planete.info/actualites/actu_1032_Espagne_plus_grande_centrale_thermosolaire_Europe.php
}\label{pCSP}
}%
World power consumption today is 15\,000\,GW\@.
So the correct statement about power from the \ind{Sahara} is that
{today's} consumption could be provided by
a {\em 1000\,km by 1000\,km\/} \index{square in desert}{square} in the \ind{desert},
completely filled with \ind{concentrating solar power}.
%% the guardian link above says that the UN said that
%% you could get enough ELEC for the whole world from 640 000 sq km
That's four times the area of the UK.
% United Kingdom.
And if we are interested in living in an equitable world, we should
presumably aim to supply more than
{\em{today's}\/} consumption.
To supply every person in the world with an average
European's power consumption (\europe\,kWh/d),
% 6e9 * 125 * 40
the area required would\label{FirstCSP}
% 30\,000\,GW
be {\em{two}\/} 1000\,km by 1000\,km squares in the desert.
% or eight United Kingdoms.
%# 590*590 *1e6 * 15 / 1e9 *24 /1000
%# ans = 125
% europe's electrical capacity is 700 GW\@.
%# 145*145 *1e6 * 15 / 60e6 *24 /1000
%% 126
Fortunately, the Sahara is not the only desert, so
maybe it's more relevant to chop the world
into smaller regions, and ask what area is needed
in each region's local desert. So, focusing on Europe,
``what area is required in the North Sahara to supply
{\em{everyone in Europe and North Africa}\/} with
an average European's power consumption?
Taking the population of Europe and North Africa to be
%# 580 x 580 km is more accurate
1 billion, the area required drops to 340\,000\,km$^2$,
which corresponds to a square {\bf{600\,km by 600\,km}}.
This area is equal to one Germany,
% 357000,
to 1.4
% $1\dfrac{1}{3}$
United Kingdoms, or to
{\bf{16 Waleses}}.
% 360000
% 20700 16.4 wales in fact
\begin{figure}
\figuredanglenudge{
\begin{center}
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/africaSquare.eps}}\\
\end{center}
}{
\caption[a]{The celebrated little square.
This map shows a square of size 600\,km by 600\,km in Africa,
and another in Saudi Arabia, Jordan, and Iraq.
Concentrating solar power facilities
% delivering on average
% 15\,\Wmm\
completely filling one such square would provide
enough power to give 1 billion people the average European's
consumption of 125\,kWh/d.
The area of one square is the same as the area of Germany,
and 16 times the area of Wales.
Within each big square is a smaller 145\,km by 145\,km square
showing the area required in the Sahara -- one Wales -- to supply
all British power consumption.
}
\label{libya0}
}{22mm}
\end{figure}%
The UK's share of this 16-Wales area would be one Wales: a 145\,km
by 145\,km square in the Sahara would provide all the UK's current
primary energy consumption.
These squares are shown in \figref{libya0}.
Notice that while the yellow square may look ``little''
compared with Africa, it does have the same area as Germany.
\subsection{The DESERTEC plan}
An organization called DESERTEC [\myurlb{www.desertec.org}{http://www.desertec.org/}]
is promoting
a plan to use concentrating solar power in sunny Mediterranean
countries, and high-voltage direct-current (\ind{HVDC})
transmission lines (figure \ref{pHVDC2})
% and \ref{pHVDC})
to deliver the power to cloudier northern parts.
HVDC technology has been in use since 1954 to transmit
power both through overhead lines and through submarine cables
(such as the interconnector between France and England).\index{interconnector!England--France}
It is already used to transmit electricity over 1000-km distances in
South Africa, China, America,
% hvdc from mozambique to south africa
Canada, Brazil, and Congo.\nlabel{pCongo}
% usually at 500 kV.
% each line transmits 2GW or so.
A typical 500\,kV line can transmit a power of 2\,GW\@.
% http://en.wikipedia.org/wiki/HVDC_Itaipu
A pair of HVDC lines in Brazil transmits 6.3\,GW\@.
% http://www.abb.com/cawp/gad02181/c1256d71001e0037c1256833006cb3a4.aspx?
% In total 80\,GW of power-transmission exists
% http://www.abb.com/cawp/gad02181/c1256d71001e0037c1256c330030750d.aspx
% The losses in each converter station are
% about 0.6\% of the transmitted power.
HVDC is preferred over traditional high-voltage AC lines because
less physical hardware is needed, less land area is needed,
and the power losses of HVDC are smaller. The power losses\index{transmission losses}
on a 3500\,km-long HVDC line, including conversion from AC to DC and back,
would be about 15\%.\nlabel{lossesHV}
% in transmission from Algeria or Libya to Britain would be roughly 15\%.
% And what would AC be?
A further advantage of HVDC systems
is that they help stabilize the electricity networks to which they
are connected.
In the DESERTEC plans, the prime areas to exploit are coastal
areas, because concentrating solar power stations that are near to the sea
can deliver desalinated water as a by-product -- valuable
for human use, and for agriculture.
\begin{table}
\figuremargin{
\begin{tabular}{lrr} \toprule
Country & Economic potential & Coastal potential \\
& (TWh/y) & (TWh/y) \\
\midrule
Algeria & 169\,000 & 60\\% 168971
Libya & 140\,000 & 500\\% 139470
Saudi Arabia
& 125\,000 & 2\,000\\% 124560
Egypt & 74\,000 & 500\\% 73655
Iraq & 29\,000 & 60\\% 28647
Morocco & 20\,000 & 300\\% 20146
Oman & 19\,000 & 500\\% 19404
Syria & 10\,000 & 0\\% 10210
Tunisia & 9\,200 & 350\\
Jordan & 6\,400 & 0\\
Yemen & 5\,100 & 390\\
Israel & 3\,100 & 1\\
UAE & 2\,000 & 540\\
Kuwait & 1\,500 & 130\\
Spain & 1\,300 & 70\\
Qatar & 800 & 320\\
Portugal& 140 & 7\\
Turkey & 130 & 12\\
\midrule
Total & 620\,000& 6\,000 \\% the above sum to 585063
& (70\,000\,GW) & (650\,GW)\\
%% 650 GW is 16\,kWh per day each for 1 billion people.
\bottomrule
\end{tabular}
}{
\caption[a]{
Solar power potential in countries around and near to Europe,
as estimated by DESERTEC.
The ``economic potential''
is the power that could be generated in suitable places
where the \ind{direct normal irradiance}
is more than 2000\,kWh/m$^2$/y.
The ``coastal potential''
is the power that could be generated
within 20\,m (vertical) of sea level;
such power is especially promising because of the
potential combination with desalination.
For comparison,
the total power required to give 125\,kWh per day
to 1 billion people is 46\,000\,TWh/y (5\,200\,GW).
6000\,TWh/y (650\,GW) is 16\,kWh per day per person for 1 billion people.
}\label{CSPtab}
}
\end{table}
\Tabref{CSPtab} shows DESERTEC's estimates of
the potential power that could be produced in countries
in Europe and North Africa.
\marginfig{
\begin{center}\vspace{-10mm}\par
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/CableABB.eps}}}
\end{tabular}
\end{center}
\caption[a]{Laying a high-voltage DC link between Finland and Estonia.
A pair of these cables transmit a power of 350\,MW\@.
Photo: ABB\@.
}\label{pHVDC2}
}%
The ``economic potential'' adds up to more than enough to
supply 125\,kWh per day
to 1 billion people.
The total ``coastal potential'' is enough to supply
16\,kWh per day per person to 1 billion people.
\begin{figure}
\figuremargin{
\begin{center}
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/libya2.eps,angle=270}}\\
\end{center}
}{
\caption[a]{Each circular \ind{blob} represents
an area of 1500\,km$^2$, which, if
% one-third-filled with
one-half-filled with
solar power facilities, would generate 10\,GW on average.
65 such blobs would provide 1 billion people
with 16\,kWh/d per person.
}
\label{libya}
}
\end{figure}%
Let's try to convey on a map what a realistic plan could look
like. Imagine making solar facilities each having an area of
1500\,km$^2$ -- that's roughly the size of London.
(Greater London has an area of 1580\,km$^2$;
the M25 orbital motorway around London encloses an area of 2300\,km$^2$.)
Let's call each facility a {\dem{blob}}.
Imagine that in each of these blobs, half the area is devoted to
concentrating power stations with an average power per unit area of 15\,\Wmm,
leaving space around for agriculture, buildings, railways,
roads, pipelines, and cables. Allowing for 10\% transmission loss\index{transmission losses}
between the blob and the consumer, each of these blobs generates
an average power of 10\,GW\@.
% ( 4 kWh/d/p in the UK )
\Figref{libya} shows some blobs to scale on a map.
To give a sense of the scale of these blobs I've dropped a
few in Britain too.
{\em{Four}\/} of these blobs would have an output roughly equal
to Britain's total electricity consumption (16\,kWh/d per person for
60 million people).
{\em{Sixty-five}\/} blobs would provide all one billion
people in Europe and North Africa with 16\,kWh/d per person.
\Figref{libya} shows 68 blobs in the desert.
% The average power of 65 blobs would be 650\,GW;
% their generating capacity would be about 2500\,GW\@. To build
% up this capacity between 2010 and 2050, an average building rate
% of 65\,GW of capacity per year is required.
}
\subsection{Concentrating photovoltaics}
An\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/CPV.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{
A 25\,kW (peak) concentrator photovoltaic
collector produced by Californian company \ind{Amonix}.
Its
225\,m$^2$ aperture contains 5760 Fresnel lenses with optical
concentration $\times 260$,
each of which illuminates a 25\%-efficient silicon cell.
%¼ 25%. The conceptual collector discussed in the present paper
%would have a reduced aperture ¼ 200 m2, and only 3200 (triple-junction)
%CPV cells with 32% STC efficiency. Its Fresnel lenses would have optical
%concentration ¼ 625 Â (
One such collector, in an appropriate desert location, generates
138\,kWh per day -- enough to cover the energy consumption of
half an American. Note the human providing a scale.
Photo by David Faiman.
}\label{Faiman}
}
alternative to
concentrating thermal solar power in deserts is large-scale
concentrating photovoltaic
systems\index{concentrator photovoltaics}. To make these, we plop
a high-quality electricity-producing
solar cell at the focus of cheap lenses or mirrors.
% they call it \section{Concentrator photovoltaics} CPV
\citet{ConcentratingPV} say that
``solar, in its \ind{concentrator photovoltaics}
variety, can be completely cost-competitive with fossil fuel
[in desert states such as \ind{California}, \ind{Arizona},
\ind{New Mexico}, and \ind{Texas}]
without the need for any kind of subsidy.''
According to manufacturers Amonix,\nlabel{pAmonix}
this form of concentrating solar power would have
an average power per unit land area of \powerd{18\,\Wmm}.
% tracking the sun gives a 30% gain they say
% http://www.amonix.com/technical_papers.html
% passively cooled
%Fig. 1. Photograph of an existing Amonix 25 kWp CPV collector. Its
%225 m2 aperture consists of 5760 Fresnel lenses with optical con-
%centration ¼ 260 Â , each of which illuminates a Si CPV cell of STC
%efficiency ¼ 25%. The conceptual collector discussed in the present paper
%would have a reduced aperture ¼ 200 m2, and only 3200 (triple-junction)
%CPV cells with 32% STC efficiency. Its Fresnel lenses would have optical
%concentration ¼ 625 Â (photograph, D. Faiman).
% Raviv estimated that a production facility with an MAKING THE POWER STATIONS
%annual throughput of 1 GWp of solar collectors and
%0.35 GW of storage batteries should cost 850 M$ to set
%up. This figure includes an estimated 220 M$ for first-time
%engineering research and development (R&D) costs. For
% According to Raviv's estimates, a 1 GWp VLS-PV solar
%plant including 0.35 GW of storage should cost 1135 M$.
%285 M$ for storage batteries (Vanadium Redox flow
%batteries with 6 h effective storage, which Raviv estimates
%could be mass-produced for $850 kWÀ1).
% COULD pay for itself assuming electricity sold for 4.13 c/kWh long term. Or 4.45,
% including the cost of replacing them every 35 y.
Another way to get a feel for required hardware is to personalize.
One of the ``25\,kW'' (peak) collectors shown in \figref{Faiman} generates on average
about 138\,kWh per day; the American lifestyle currently uses 250\,kWh per day
per person.
So to get the USA off fossil fuels using solar power, we need roughly two of
these 15\,m$\,\times\,$15\,m collectors per person.
%City: ","DAGGETT "
%"State: ","CA"
%"WBAN No: ", 23161
%"Lat(N): ", 34.87
%"Long(W): ",116.78
%"Elev(m): ", 588
% For a site having our baseline NDI of 2222 kWh/m$^2$
%year, each 1 GWp of solar collectors would require
%12 km$^2$ of land. However, in the California desert, NDI
%figures are considerably higher (Marion and Wilcox, 1994).
%For example, Dagget CA has recorded figures in the range
%2300-Â2920 kWh/m$^2$/year.
% So each GWp would require only 10km**2.
% california current cpaacity is 57GW and they generate 184 TWh
% 1.63 kW/capita, 5.3 MWh/capita/y
% For CA, they would like to have 510 km**2 of desert, to put up 52.6
% GWp, which would deliver all the _increase_ in required power.
% requires investment of $1.1b now. The cost per produced
% (1.5GWp) (including 0.5GW storage) power station
% would be $1.7b
% A 1.5GWp plant would have 30,000 50kWp collectors.
% 2004 retail elec price is 10.55c/kWh
%\section{Solar updraft tower}
% Notes in solarth.tex
\section{Queries}
\beforeqa
\qa{I'm confused! In \chref{ch.solar}, you said that
the best photovoltaic panels deliver 20\,\nWmmb\ on average, in a place with
British sunniness. Presumably in the desert the same panels
would deliver 40\,\nWmmb.
So how come the concentrating solar power stations deliver only 15--20\,\nWmmb?
Surely concentrating power should be even better than plain flat panels?}{
Good question.
The short answer is no.
Concentrating solar power does not achieve a better power per unit land
area than flat panels. The concentrating contraption has to
track the sun, otherwise the sunlight won't be focused right; once
you start packing land with sun-tracking contraptions, you have to
leave gaps between them; lots of sunlight falls through the gaps
and is lost.
The reason that people nevertheless make concentrating solar power systems
is that, today, flat photovoltaic panels are very expensive, and
concentrating systems are cheaper.
The concentrating people's
goal is not to make systems with big power per unit land area. Land area
is cheap (they assume). The goal is to deliver big power per dollar.
%%% CUTTABLE from here to end of qa
% cut.
}
\qa{But if flat panels have bigger power per unit area, why don't you
describe covering the Sahara desert with {\em{them}}?}{
Because I am trying to discuss practical options for large-scale sustainable
power production for Europe and North Africa by 2050. My guess is that
by 2050, mirrors will still be cheaper than photovoltaic panels,
so concentrating solar power is the technology on which we should focus.
}
\qa{What about solar chimneys?}{
\index{solar updraft tower}\index{solar chimney}\index{chimney!solar}\index{updraft tower!solar}A
solar chimney or solar updraft tower
uses solar power in a very simple way.\nlabel{pChimn}
A huge chimney is built at the centre of an area covered by a transparent
roof made of glass or plastic; because hot air rises,
hot air created in this greenhouse-like heat-collector
whooshes up the chimney, drawing in cooler air from the perimeter of the
heat-collector. Power is extracted from the air-flow
by turbines at the base of the chimney.
Solar chimneys are fairly simple to build, but they don't deliver a very impressive
power per unit area.
A pilot plant in \ind{Manzanares}, \ind{Spain}
operated for seven years between 1982 and 1989.
The chimney had a height of 195\,m and a diameter of 10\,m;
the collector had a diameter of 240\,m, and its roof
had $6000\,\m^2$ of glass and $40\,000\,\m^2$ of transparent plastic.
% , and
% generated a peak output of 50\,kW.
% Chimney height / diameter: 195m / 10m; Collector Diameter: 240m. $6000\,\m^2$ of glass,
% $40\,000\,\m^2$ of plastic roof.
It generated 44\,MWh per year, which corresponds to a power per unit area
of \pdcol{0.1\,\Wmm}.
\amarginfig{b}{
\begin{center}
{\epsfxsize=53mm{\epsfbox{../../images/manzanares.eps}}}\\
{\epsfxsize=53mm{\epsfbox{../../images/manzanares2.eps}}}
\end{center}
%}{
\caption[a]{The Manzanares prototype solar chimney.
Photos from \myurl{solarmillennium.de}.
}
}%
Theoretically, the bigger the collector and the taller the chimney, the
bigger the power density of a solar chimney becomes.
The engineers behind Manzanares
reckon that, at a site with a solar radiation of
2300\,kWh/m$^2$ per year (262\,\Wmm),
% \citet{schlaich05}
a 1000\,m-high tower
surrounded by a 7\,km-diameter collector could
generate 680\,GWh per year, an average power of 78\,MW\@.
% 78MW average; 200MW peak
% Allowing 7km square for this so there is a 1km gap...
% 680 GWh per year / 7km/7km in W/m/m
That's a power per unit area of about \pdcol{1.6\,\Wmm},
which is similar to the power per unit area of windfarms in
Britain, and
one tenth of the power per unit area
I said concentrating solar power stations would deliver.
It's claimed that solar chimneys could generate electricity
at a price similar to that of conventional power stations.
I suggest that countries that have enough land
and sunshine to spare should host a big bake-off contest
between solar chimneys
and concentrating solar power, to be funded by oil-producing
and oil-consuming countries.
}
\qa{What about getting power from
Iceland, where\index{geothermal!Iceland}\index{hydroelectricity!Iceland}
geothermal power and
hydroelectricity are so plentiful?
}{
Indeed, \ind{Iceland} already effectively exports energy by
powering industries that make energy-intensive
products. Iceland produces nearly one \tonne\ of
\index{aluminium!Iceland}{aluminium} per
\amarginfig{t}{
\begin{center}
\epsfxsize=53mm%
\lowres%
{\epsfbox{../../images/GeothermalIceland1S.eps}}%
{\epsfbox{../../images/GeothermalIceland1.eps}}
\end{center}
%}{
\caption[a]{More geothermal power
in \ind{Iceland}.
%% In Iceland, there are five major geothermal power plants which produce about 26% (2006) of the country's electricity. In addition, geothermal heating meets the heating and hot water requirements for around 87% of the nation's housing.%% remainder of elec is from hydro
% LOWER: The Nesjavellir Geothermal Power Plant in Iceland
% produces 120MW of elec and 300 MW of heating water.
Photo by Rosie Ward.
% stats from
% http://www.os.is/page/energystatistics
}
%\end{figure}
}%
citizen per year, for example! So from Iceland's point of view, there are
great profits to be made.
But can Iceland save Europe?
I would be surprised if Iceland's power production
could be scaled up enough to make sizeable electricity exports
even to Britain alone.
As a benchmark, let's compare with the\index{England--France interconnector}
\index{interconnector!England--France}England--France
Interconnector, which can deliver up to 2\,GW\index{interconnector!Iceland}
across the English Channel. That maximum power is
equivalent to 0.8\,kWh per day per person in the UK, roughly 5\% of
British average electricity consumption.
\ind{Iceland}'s average geothermal electricity generation
is just 0.3\,GW, which is less than 1\% of Britain's
average electricity consumption.\nlabel{pIceGeo}
Iceland's average electricity production is 1.1\,GW\@.
So to create a link sending power equal to the capacity of the French interconnector,
Iceland would have to {\em triple\/} its electricity production.
To provide us with
4\,kWh per day per person (roughly what Britain gets from its
own nuclear power stations), Iceland's electricity
production would have to increase {\em ten-fold}.
It is probably a good idea to build interconnectors to
Iceland, but don't expect them to deliver more than a small
contribution.
}
\small
\section*{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
%
\item[\npageref{pCSP15}]
{\nqs{Concentrating solar power in deserts
delivers an average power per unit area
of roughly 15\,\nWmm.}}
My sources for this number are two companies making
concentrating solar power for deserts.\index{power density!concentrating solar power}
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/esolar83.eps}}}%
\\
\end{tabular}
\end{center}
\caption[a]{Two engineers assembling an eSolar
% prototype
concentrating power station using \ind{heliostats} (mirrors that rotate and tip
to follow the sun).
\myurl{esolar.com}
make medium-scale power stations:
a 33\,MW (peak) power unit on
% 160 acres (64 hectares).
a 64 hectare site.
That's 51\,\Wmm\ peak, so I'd guess that in a typical desert location
they would deliver about one quarter of that: \powerd{13\,\Wmm}.
}
}
\myurl{www.stirlingenergy.com} says one of its dishes
with a 25\,kW \ind{Stirling engine} at its focus
can generate 60\,000\,kWh/y in a favourable desert location.
%% that is 7kW average (6.84)
They could be packed at a concentration of
one dish per 500\,m$^2$.
% 8 per acre. 506m**2
%% http://www.stirlingenergy.com/faq.asp?Type=all
%% 8 * 60 000 ((kWh / acre) / year) = 13.5310423 W / (m ** 2)
That's an average power of \powerd{14\,\Wmm}.
%% the engine runs at 1800 rpm. output 480 V, 60 Hz.
They say that solar dish Stirling makes the best use
of land area, in terms of energy delivered.
\myurlb{www.ausra.com}{http://www.ausra.com/}
uses flat mirrors\index{Ausra}
to heat water to 285\degreesC\ and
drive a steam turbine. The heated,
pressurized water can be stored in deep metal-lined caverns
% storage facil cost: $3 per kWh(t) (installed cost)
to allow power generation at night.
% Email from John O Donnell says
% need 2 sq mi to get 175MW * 0.4
% which is 0.4*175MW/(2 square miles) in W/m**2
% 13.5135755 W / (m ** 2)
% need 1 sq mi to get 175MW * 0.3
% ``See APS Solana''
% Rankine cycle
Describing a ``240 \MWe'' plant
proposed for Australia \citep{DMills},
the designers claim that 3.5\,km$^2$ of mirrors
would deliver 1.2\,\TWhe; that's
% 134 MW
38\,\Wmm\ of mirror.
% page 6 of 9 in DMills
% 4.3 aus cents per kWh , sell for 8 cents
To find the power per unit land area, we need to
allow for the gaps between the mirrors.
% Allowing for a bit of space for
% humans and other administrative hardware,
% that's a power density of perhaps 30\,\Wmm\ of land.
%
Ausra say they need
a 153\,km by 153\,km square
in the desert
to supply all US electric power \citep{CLFR3}.
% at 8 cents per kWh
% capital cost: 1784$ per kWe with 54% capacity factor
Total US electricity is 3600\,TWh/y, so they are
claiming a power per unit land area of \powerd{18\,\Wmm}.
% was 18.7 when it was a 92 mile square
% \myurl{http://www.aceee.org/conf/06modeling/azevado.pdf}
This technology goes by the name
{\em\ind{compact linear fresnel reflector}} \citep{CLFR,CLFR2,CLFR3}.
% theory paper says 5.6 (or even 12) MJ per sq m per day. (per area of mirror)
% 5.6 MJ per square m per day in W / square meter That is 65 W/mm of mirror
Incidentally, rather than ``\ind{concentrating solar power},'' the
company Ausra prefers to use the term {\em\ind{solar thermal electricity}\/}
(\ind{STE}); they emphasize the benefits of thermal storage, in contrast
to concentrating photovoltaics, which don't come with a natural storage
option.
% CLFR3 says 1.5 square miles for 177 MW, but is not clear whether this is
% peak or average.
% 177e6 W / 1.5 miles**2 in W / m**2 46W/mm
% says US electricity from 153km 153km
% 3600e12 watt hour / ( 153km * 153km ) / year in W / m**2
% 17.5 Wmm
\citet{TriebKnies}, who are strong proponents of
concentrating solar power,
project that the alternative
concentrating solar power
technologies
% page 27 Trieb.pdf
would have powers
per unit land area in the following ranges:
parabolic troughs, \pdcol{14--19\,\Wmm};
linear fresnel collector, \pdcol{19--28\,\Wmm};
tower with heliostats, \pdcol{9--14\,\Wmm};
stirling dish, \pdcol{9--14\,\Wmm}.
There are three European demonstration plants for concentrating solar power.
Andasol -- using parabolic troughs;
{Sol\'ucar} \index{Solucar@Sol\'ucar}\ind{PS10}, a tower near \ind{Seville};
and Solartres, a tower using molten salt for heat storage.
% cost 15.3 mill euro AIMING for 2500euro per kWe
The Andasol parabolic-trough system shown in \figref{pCSP}
is predicted to deliver \powerd{10\,\Wmm}.
% SOLUCAR
% {\nqs{\ind{Solucar}}}:
% {\nqs{\ind{Sol\'ucar}}}:
%% http://www.solarpaces.org/Tasks/Task1/PS10.HTM total cost 35 M euro
%% opened 30 march 2007
{Sol\'ucar}'s ``11\,MW'' solar tower has 624 mirrors, each 121\,m$^2$.
The mirrors concentrate sunlight to a radiation density of up to
650\,k\Wmm. The receiver receives a peak power of 55\,MW\@.
The power station can store 20\,MWh of thermal energy, allowing it
to keep going during 50 minutes of cloudiness.
It was expected to generate 24.2\,GWh of electricity per year, and
it occupies 55\,hectares.
%% 60 ha in the annual report.
% 55ha according to EU document which says 23GWh/y
% feedintariff of 18 c per kWh
% 2.8MW average
% the mirrors themselves are 7.5ha.
That's an average power per unit land area of \powerd{5\,\Wmm}.
(Source: Abengoa Annual Report 2003.)
% http://www.abengoa.es/sites/abengoa/resources/pdf/en/gobierno_corporativo/informes_anuales/2003/2003_AnnualReport_IDI.pdf
% http://www.upcomillas.es/catedras/crm/report05/Comunicaciones/Mesa%20IV/D.%20Valerio%20Fern%C3%A1ndez%20-%20Solucar%202.pdf
% agrees fairly closely with the above.
Solartres will occupy 142 hectares
% 2480 mirrors with a surface area of 28.5ha.
% will have a 17MW turbine and on average produce 11MW?
and is expected to produce 96.4\,GWh per year;
that's a power per unit area of \powerd{8\,\Wmm}.
\ind{Andasol} and \ind{Solartres} will both use some natural
gas in normal operation.
% up to 16MW thermal of gas?
% 6250 t of molten salt in storage. stores 647 MWh. (15 h worth!)
\item[\npageref{pCongo}]
{\nqs{HVDC is already used
to transmit electricity
over 1000-km distances in
South Africa, China, America,
Canada, Brazil, and Congo.}}
Sources: \citet{Asplund},
\citet{HVDCABC}.
%
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ABBHVDC.eps}}}
\end{tabular}
\end{center}
\caption[a]{A high-voltage DC power system in China.
Photo: ABB\@.
}\label{pHVDC}
}%
Further reading on HVDC: \cite{HVDCreview}.
% From \cite{HVDCABC},
% savings in line construction: roughly 30\% relative to AC.
%
% the number of cables needed for HVDC is roughly 40\% of AC.
% , and there are network stability benefits.
% Losses for different AC and DC transmission alternatives for
% a hypothetical 750-mile (1200\,km), 3,000-MW transmission system:
% Best (lowest loss) DC option: 3.43\% (103\,MW).
% Cost: \$2b.
% Cheaper option: losses 6.44\%
% Best AC option: 4.62\% (139\,MW).
% \$4.8b.
% Compare with coal taken 900 miles by rail
% to a 3GW power station.
% (8500 Btu per kWh, and
% 8500 Btu per lb. 1lb of coal
% is 1kWh of heat!!
% presume US gal
% Rail: 500 ton-miles per
% gallon, so 20 million gallons of
% diesel per year. Which is 1GW
%
\setcounter{latestnotepage}{0}
\item[\npageref{lossesHV}]
{\nqs{Losses on a 3500\,km-long HVDC line, including conversion from AC to DC and back,
would be about 15\%.}} Sources:
\cite{TriebKnies,CSPvanV}.
\item[\npageref{pAmonix}]
{\nqs{According to Amonix, concentrating photovoltaics would have
an average power per unit land area of 18\,\nWmm.
}}
% lens transmits 85%
The assumptions of \myurlb{www.amonix.com}{http://www.amonix.com/}
are: the lens transmits 85\% of the light;
32\% cell efficiency; 25\% collector efficiency; and 10\% further
loss due to shading. Aperture/land ratio of 1/3.
Normal direct irradiance: 2222\,kWh/m$^2$/year.
They expect each kW of peak capacity to deliver 2000\,kWh/y (an average of 0.23\,kW).
% (So average production 23\% of nameplate peak power.)
A
%VLSÂPV
plant of 1\,GW peak capacity would occupy 12 km$^2$
of land and deliver 2000\,GWh per year.
That's \powerd{18\,\Wmm}.
% 18.2
\item[\npageref{pChimn}]
{\nqs{Solar chimneys.}}
Sources:
\citet{schlaich01:_solar_chimn,schlaich05,NatureChimney},
\myurlb{www.enviromission.com.au}{http://www.enviromission.com.au/},
%% would cost austral $ 800 million (US 610$M)
%% Schlaich J, Schiel W (2001), "Solar Chimneys", in RA Meyers (ed), Encyclopedia of Physical Science and Technology, 3rd Edition, Academic Press, London. ISBN 0-12-227410-5
%% http://www.solarmillennium.de/pdf/SolarCh.pdf
%% http://en.wikipedia.org/wiki/Tapio_Station
%% http://www.enviromission.com.au/news/news-02-03solarpower3.htm
% two `solar tower' designs are described in Nature
% vol 443 (7 Sept 2006) p 23-24.
% A similar solar power station design called the
% \ind{accelerated air-flow farm} is promoted by
% the California-based company SolarAirPower
% \myurl{http://www.solarairpower.com/}. Their website gives no details.
\myurlb{www.solarairpower.com}{http://www.solarairpower.com/}.
% photo sources
% http://www.solarmillennium.de/Technologie/Aufwind_Kraftwerke/Pilotprojekt/Im_Pilotprojekt_wurde_die_Funktionsfaehigkeit_nachgewiesen__,lang1,108.html
% *** why no colour?
\item[\npageref{pIceGeo}]
{\nqs{\ind{Iceland}'s average geothermal electricity generation
is just 0.3\,GW. Iceland's average electricity production is 1.1\,GW\@.}}
These are the statistics for 2006:
7.3\,TWh of hydroelectricity and 2.6\,TWh of geothermal
electricity, with capacities of
1.16\,GW and 0.42\,GW, respectively.
Source: Orkustofnun National Energy Authority
[\myurlb{www.os.is/page/energystatistics}{http://www.os.is/page/energystatistics}].
\item[Further reading:]
% PS10_solarthermal.jpg
% (Photo courtesy Solar PACES)
% PS10_solar_power_tower_2.txt
% PS10_solar_power_tower_2.jpg
\cite{CSPEU},
% Solar dish with Stirling currently cost
% 11\,000\euro\ per \kWe.
\cite{CSPforMR},
% According to
\myurlb{www.solarmillennium.de}{http://www.solarmillennium.de/}.
% ``The cost for generating electric power is 3 to 5 times lower with solar thermia than with photovoltaics.''
%``Dan Lewis, energy expert at the Economic Research Council, calculates that
% CSP costs \$3--5m per installed megawatt.''
%% SOLAR TWO was 8% efficient at sun to elec conversion \cite{WEAch7}
%% Land use: solar thermal plants need 1 sq km for 60 MW of capacity (peak) \cite{WEAch7}
%% which is 60 W / mm peak . So plausibly 15 W mm average.
%% but STE, CLFR, might improve 3-fold.
%% compact linear fresnel reflector sydney
%% looks identical to AUSRA
\end{notelist}
\normalsize
% the TREC document talks about 0.24 TWhe per sq km per y, which is the same
% as 27 W/mm
% They are say that for every TWh of energy (ele?) 40 M cu m of water
% can be desalinated
% estimated ost of electricity 11-14p per kWh. (15-20 cents)
% but they antiipate egttin the cost down to 10 eurocents. or to 4-5 eurocents
% if many are built.
% solar towers being built by
% http://www.brightsourceenergy.com/faq.htm
% see also
% http://www.luz2.com/
% pilot plant
% site area is about 0.5*406*290= 59000, with 12000 of mirrors
% No elec produced. Intended to make 6MWth.
% That is a peak power of 100 Wmm.
% If allow 40% efficient, 40Wmm elec; and daylight 25% gives 10Wmm best
% guess.
% supply side
\bset\chapter{\bcol{Fluctuations and storage}}
% \chapter{Storage of energy}
\label{ch.storage}
\myquote{The wind, as a direct motive power,
is wholly inapplicable to a system of
machine labour, for during a calm
season the whole business of the country
would be thrown out of gear. Before
the era of steam-engines, windmills were
tried for draining mines; but though
they were powerful machines, they were very
irregular, so that in a long tract of \ind{calm weather}
the \ind{mine}s were drowned, and all the workmen
thrown idle.
}{William Stanley Jevons, 1865\index{Jevons, William Stanley}}
% \end{quote}
%\section{Why we need storage systems}
\begin{figure}[hbtp]
\figuredangle{
\begin{center}
\begin{tabular}{c}
\mono%
{\mbox{\epsfysize=2.182in\epsfbox{../../data/NationalGrid/JanJun.eps}}}%
{\mbox{\epsfysize=2.182in\epsfbox{../../data/NationalGrid/colo/JanJun.eps}}}%
\\
%{\mbox{\epsfysize=2.182in\epsfbox{../../data/NationalGrid/JanJunGW.eps}}} \\
\end{tabular}
\end{center}
}{
\caption[a]{Electricity demand\index{demand!electricity}
in Great Britain
(in kWh/d per person)\index{Britain!electricity demand}
during two winter
weeks and two summer weeks of 2006.
The peaks in January are at 6pm each day.
The five-day working week is evident in summer and winter.
(If you'd like
to obtain the national demand in GW, remember the top of the scale,
24\,kWh/d per person, is the same as 60\,GW per UK.)
}
\label{fig.demand}
}
\end{figure}
If we kick fossil fuels and go all-out for renewables,
{\em{or}\/} all-out for nuclear,
{\em{or}\/} a mixture of the two,
we may have a problem.\index{fluctuations}\index{nuclear power!inflexibility}\index{renewables, intermittency}
Most of the big renewables are not \ind{turn-off-and-onable}.
% http://www.atomfilms.com/film/creature_comforts.jsp
When the wind blows and the sun comes out,
% the tide turns, and
power is there for the taking; but maybe
two hours later, it's not
available any more.
Nuclear power stations are not usually designed
to be turn-off-and-onable either.
They are usually on all the time, and their delivered power
can be turned down and up only on a timescale of hours.
This is a problem because, on an electricity network,
consumption and production must be exactly equal all the time.
The electricity grid can't {\em store\/} energy.
To have an energy plan that adds up every minute of every day,
we therefore need {\em{something \ind{easily turn-off-and-onable}}}.
It's commonly assumed that the easily turn-off-and-onable something
should be a {\em{source}\/} of power that gets turned off and on
to compensate for the fluctuations of supply relative to demand (for example,
a fossil fuel power station!).
But another equally effective way to match supply and demand would
be to have an easily turn-off-and-onable {\em{demand}\/} for power --
a sink of power that can be turned off and on at the drop of a hat.
Either way, the easily turn-off-and-onable something needs to be
a {\em{big}\/} something\index{energy demand variations}
because \index{electricity!demand varies}{electricity demand varies} a lot (\figref{fig.demand}).
The demand sometimes changes significantly on a timescale
of a few minutes. This chapter discusses how to cope
with fluctuations in supply and demand, without using fossil fuels.
%% either make this with data/windEire/gnu or gnud (for dots instead of lines)
%% gnu is the up to date one with all the gray lines done nicely
\begin{figure}[tbp]
\figuremargin{
\begin{raggedright}
\hspace*{2mm}\hspace*{0.025\textwidth}
\begin{tabular}{l}
\mbox{\epsfxsize=0.9\textwidth\epsfbox{../data/windEire/OneYearWind.eps}} \\[0.372in]
\mbox{\epsfxsize=0.95143\textwidth\epsfbox{../data/windEire/FourMonthWind.eps}} \\[0.372in]
\mbox{\epsfxsize=1.35\textwidth\epsfbox{../data/windEire/OneMonthWind.eps}} \\
\end{tabular}
\end{raggedright}
}{
\caption[a]{Total output, in MW, of all {\windfarm}s of the
Republic of \ind{Ireland},
from April 2006 to April 2007 (top), and detail from
January 2007 to April 2007 (middle), and
February 2007 (bottom).
Peak electricity demand in Ireland is about 5000\,MW\@. Its wind ``capacity'' in 2007
is 745\,MW, dispersed in about 60 {\windfarm}s.
Data are provided every 15 minutes by \myurl{www.eirgrid.com}.
% Did I include NI farms? in jan 2008 there's 108MW in northern ireland
}
\label{fig.eire.wind}
}
\end{figure}
% in real time as a daily plot, and
% look back at past days too (at {\tt{tinyurl}}
% \tinyurl{2hxf6c}{http://www.eirgrid.com/EirGridPortal/DesktopDefault.aspx?tabid=Wind\%20Generation\%20Curve&TreeLinkModID=1451&TreeLinkItemID=247}).
%% around the country.
%% round its coastline.
%% www.ewea.org
%% http://www.ewea.org/index.php?id=180
%% http://www.iwea.com/windenergy/index.html
% \Figref{fig.eire.wind} shows the total output
\section{How much do renewables fluctuate?}
%Second, most electricity production methods
%can't follow demand.
%Britain's nuclear power stations just deliver
%a steady power of about 10\,GW all the time.
%Britain's wind turbines would put out 2\,GW if the wind
%were perfect, but usually put out less, and the total
However much we love renewables, we must not kid ourselves
about the fact that wind does fluctuate.
% The power delivered by some other renewables
% such as solar and tidal electricity will also fluctuate.
% Some pro-wind folks
% The anti-wind lobby
Critics of wind power
say:\index{wind!arguments against}
``Wind power is intermittent and unpredictable,
so it can make no contribution\index{wind!intermittency}
to
\index{security of energy supply!wind}{security of supply};\index{fossil fuel!backup for wind}
if we create lots of wind power, we'll have
to maintain lots of fossil-fuel
power plant to replace the wind when it
drops.''
Headlines such as
``Loss of wind causes \ind{Texas}
power grid emergency''\nlabel{texaswind}
reinforce this view.
%%
% \section{The fluctuations of the wind}
Supporters of wind energy
play down this problem: ``Don't worry --
{\em individual\/} {\windfarm}s may be intermittent, but taken
together, the {\em sum\/}
of all {\windfarm}s in different locations
is much less intermittent.''\nlabel{pWindIntNoProb}
% {\em Slightly True}, but not as true as some wind proponents try to make
% us believe!
Let's look at real data and try to figure out a balanced
viewpoint.
%% http://www.eirgrid.com/EirGridPortal/DesktopDefault.aspx?tabid=Wind%20Generation%20Curve&TreeLinkModID=1451&TreeLinkItemID=247
%
\Figref{fig.eire.wind} shows the summed output of
the wind\index{wind!data}\index{data!wind!Ireland}
fleet\index{Ireland!wind output}
of the Republic of Ireland
from April 2006 to April 2007.\nlabel{pEireWi}
Clearly wind {\em{is}\/} intermittent, even if we add up lots of
turbines covering a whole country.
The \UK\ is a bit larger than \ind{Ireland}, but the same problem
holds there too.\nlabel{pOswald}
Between October 2006
and February 2007 there were 17 days when the output from Britain's 1632
windmills was less than 10\% of their capacity.
During that period there were five days when output was less than 5\%
and one day when it was only 2\%.
%% persists. % , for the \UK,
% And we can't expect to get lucky,
% Some of these periods of low wind coincide with periods
% of peak demand.
% It's been estimated
% that each year,
% although average wind output would be 30\% of capacity, there
% would be at least 23 one-hour periods during which
% the output from all wind turbines in the UK would be less than 10\% of
% capacity, at the same time that demand was within 90\%
% of peak demand.
%%%%%%%%%%%%%%
% "OXERA found that although average wind output is 30% of capacity, there
%will likely be at least 23 one-hour periods (46 half-hour periods) in a
%year where the output from all wind turbines in the UK is less than 10% of
%declared wind capacity, AT THE SAME TIME THAT DEMAND IS 90% OR MORE ANNUAL
%PEAK DEMAND (i.e. 23 hours out of that sub-set of demand data where demand
%is within 10% of max-demand, this is the crucial time). This is after
%making allowance for the benefits of wind turbines being distributed around
%the UK including some modelled off-shore".
%"They added that there would likely be at least 186 one-hour periods when
%wind output is between 10% and 30% of capacity, whilst at the same times
%demand is in excess of 80% of peak demand".
%}
Let's quantify the fluctuations in country-wide wind power.
The two issues are short-term changes, and long-term lulls.
Let's find the fastest short-term change in a month of Irish wind data.
On 11th February 2007, the Irish wind power\index{wind!Irish} fell steadily from 415\,MW
at midnight to 79\,MW at 4am.\index{data!wind power fluctuations}
That's a \ind{slew rate} of 84\,MW per hour for a country-wide
fleet of capacity 745\,MW\@.
(By slew rate I mean the rate at which the delivered power fell or rose -- the
slope of the graph on 11th February.)
OK: if we scale British wind power up
% 16-fold
to a capacity of 33\,GW (so that it delivers 10\,GW on average),
we can expect to have occasional slew rates of
\[
{84\,\MWph} \times
\frac{33\,000\,\MW}{745\,\MW} = 3700\,\MWph,
\]
assuming Britain is like Ireland.
So we need to be able to either power {\em{up}\/} replacements
for wind at a rate of 3.7\,GW per hour -- that's 4 nuclear power stations
going from no power to full power every hour, say --
{\em{or}\/} we need to be able to suddenly turn {\em{down}\/}
our {\em{demand}\/} at a rate of 3.7\,GW per hour.
% Rather than laughing at this countercultural notion and
% crucifying the na\"ive wind huggers, let's have a rummage outside the box
% and see if these windy demands could in fact be met.
Could these windy demands be met?
%
% This country-scale rummaging will require us to
In answering this question we'll need to
talk more about ``\ind{gigawatt}s.''
Gigawatts are big country-sized units of power.
They are to a country what a kilowatt-hour-per-day is to
a person: a nice convenient unit.
The UK's average electricity consumption is about 40\,GW\@.
We can relate this national number to personal consumption:
1\,kWh per day per person is equivalent to 2.5\,GW nationally.
% per UK.
So if every person uses 16\,kWh per day of electricity, then
national consumption is 40\,GW\@.
% , or, if you like, 1000\,GWh per day.
\begin{figure}
\figuredangle{
\begin{center}
\begin{tabular}{c}
\mono%
{\mbox{\epsfxsize=157mm\epsfbox{../../data/NationalGrid/JanGW.eps}}}%
{\mbox{\epsfxsize=157mm\epsfbox{../../data/NationalGrid/colo/JanGW.eps}}}%
\\
%\mono%
%{\mbox{\epsfysize=2.182in\epsfbox{../../data/NationalGrid/JanJunGW.eps}}}%
%{\mbox{\epsfysize=2.182in\epsfbox{../../data/NationalGrid/colo/JanJunGW.eps}}}%
%\\
\end{tabular}
\end{center}
}{
\caption[a]{ Electricity demand\index{demand!electricity}
in Great Britain\index{Britain!electricity demand}
during two winter weeks
% and two summer weeks
of 2006.
The left and right scales show the demand in
national units (GW) and personal
units (kWh/d per person) respectively.
These are the same data as in
% the left half of
\protect\figref{fig.demand}.
}
\label{fig.demand2}
}
\end{figure}
Is a national slew-rate of \MidnightBlue{4\,GW per hour}
completely outside human experience?
No. Every morning, as \figref{fig.demand2} shows, British demand
climbs by about {{13\,GW}\/} between 6.30am and 8.30am.
% from 32.6 at 17 halfhours to
% from 36.26 at 12 / to 48.9 at 16 /
That's a slew rate of \MidnightBlue{{\em{6.5\,GW per hour}\/}}. So our power engineers
already cope, every day, with slew rates bigger than
4\,GW per hour on the national grid.
An extra occasional slew of 4\,GW per hour
induced by sudden wind variations
% may be a problem, but it's
is no reasonable cause for ditching the idea of
country-sized {\windfarm}s. It's a problem just
like problems that engineers have already solved. We simply need
to figure out how to match ever-changing supply and demand
in a grid with no fossil fuels.
% (49.66-37.001)/([0.25207-0.33149]*24)
% ans = -6.6414
I'm not saying that the wind-slew problem is {\em{already}\/} solved --
just that it is a problem of the same size as other
problems that have been solved.
OK, before we start looking for solutions,
we need to quantify wind's other problem: long-term lulls.
At the start of February 2007,
Ireland had a country-wide lull that lasted five days.
This was not an unusual event, as you can see in
\figref{fig.eire.wind}. Lulls lasting two or three days
happen several times a year.
There are two ways to get through lulls.
Either we can store up energy somewhere before the lull,
or we need to have a way of
reducing demand during the entire lull.\index{demand management}
(Or a mix of the two.)
If we have 33\,GW of wind turbines delivering
an average power of 10\,GW then the amount of
energy we must either store up in advance
or do without during a five-day lull is
\[
10\,\GW \times (5 \times 24\,\mbox{h})
= 1200\,\GWh .
\]
(The gigawatt-hour (\GWh) is the cuddly
energy unit for nations. Britain's electricity consumption
is roughly 1000\,GWh per day.)
To personalize this quantity,
an energy store of 1200\,\GWh\ for the nation
is equivalent to an energy store of 20\,kWh per person.
Such an energy store would allow
the nation to go without 10\,GW of electricity for 5
days; or equivalently, every individual to go without
4\,kWh per day of electricity for 5 days.
\section{Coping with lulls and slews}
%\subsubsection{more to do here}
% It would be elegant to solve both problems (lulls and short-term
% slews) with a single system.
We need to solve two problems -- lulls (long periods with small
renewable production), and slews (short-term changes in either supply or demand).
We've quantified these problems, assuming that Britain had roughly 33\,GW of wind power.
To cope with lulls, we must effectively
store up roughly 1200\,GWh of energy
(20\,kWh per person).
The slew rate we must cope with is \MidnightBlue{6.5\,GW per hour} (or
0.1\,kW per hour per person).
There are two solutions, both of which could scale up to solve these problems.
The first solution is a centralized solution, and the second is
decentralized. The first solution stores up energy, then copes with
fluctuations by turning on and off a {\em{source}\/} powered from the
energy store. The second solution
works by turning on and off a piece of {\em{demand}}.
The first solution is {\dem{\ind{pumped storage}}}. The second uses the batteries of
the {\dem\ind{electric vehicles}\/} that we discussed in \chref{ch.transport}.
Before I describe these solutions, let's discuss a few other
ideas for coping with slew.
\subsection{Other supply-side ways of coping with slew}
Some of the renewables are turn-off-and-onable.
If we had a lot of renewable power that was easily turn-off-and-onable,
all the problems of this chapter would go away. Countries like \ind{Norway} and
% Norway 107.27 TWh per year of elec 119799 Gross hydro elec is produced
% http://epp.eurostat.ec.europa.eu/portal/page?_pageid=1996,39140985&_dad=portal&_schema=PORTAL&screen=detailref&language=en&product=REF_TB_energy&root=REF_TB_energy/t_nrg/t_nrg_quant/ten00092
% http://www.eia.doe.gov/emeu/cabs/Norway/Electricity.html
% Norway 27.528 GW (from wikipedia)
% Sweden 49% of 33GW is roughly 16GW
\ind{Sweden} have large and deep hydroelectric supplies which they can
turn on and off. What might the options be in Britain?
First, Britain could have lots of waste incinerators and biomass
incinerators -- power stations playing the role that is today played by
fossil power stations.
If these stations were designed to be turn-off-and-onable,
there would be cost implications, just as there are costs when we
have extra fossil power stations that are only working part-time: their
generators would sometimes be idle and sometimes work
twice as hard; and most generators aren't as efficient if you keep turning
them up and down, compared with running them at a steady speed.
OK, leaving cost to one side, the crucial question is how big a
turn-off-and-onable resource we might have.
If all municipal waste were incinerated, and an equal amount
of agricultural waste were incinerated, then the average power
from these sources would be about 3\,GW\@. If we built capacity equal
to {\em{twice}\/} this power,
making incinerators capable of delivering 6\,GW, and thus planning to have
them operate only half the time, these would be able to deliver 6\,GW
throughout periods of high demand, then zero in the wee hours. These power stations
could be designed to switch on or off within an hour, thus coping with
slew rates of 6\,GW per hour -- but only for a maximum slew range of 6\,GW!
That's a helpful contribution, but
not enough slew range in itself, if we are to cope with the fluctuations
of 33\,GW of wind.
What about hydroelectricity?
Britain's hydroelectric stations have an average load factor of 20\% so they
certainly have the potential to be turned on and off. Furthermore,
hydro has the wonderful feature that it can be turned on and off very quickly.
Glendoe, a new hydro station with a capacity of 100\,MW, will be able to switch from off
to on in 30 seconds,
for example. That's a slew rate of 12\,GW per hour in just one power station!
So a sufficiently large fleet of hydro power stations should be able to
cope with the slew introduced by enormous {\windfarm}s.
However, the capacity of the British hydro fleet
is {\em not\/} currently big enough to
make much contribution to our slew problem (assuming we want
to cope with the rapid loss of say 10 or 33\,GW of wind power).
The total capacity of traditional hydroelectric stations in
Britain is only about 1.5\,GW\@.
So simply switching on and off other renewable power sources
is not going to work in Britain. We need other solutions.
\section{Pumped storage}
% .36+.4+.3+1.8 = 2.86
% plus 2.8\,GW
% of pumped storage, a total of 4.3\,GW\@.
\begin{table}
\figuremargin{% the p{2mm} is fake, empty
\begin{tabular}{lrcrp{4mm}r@{}l} \toprule
station & power & head & volume & \multicolumn{3}{c}{energy stored} \\
& (GW) & (m) & (million m$^3$)& \multicolumn{3}{c}{(GWh)} \\ \midrule
\ind{Ffestiniog} & 0.36 & 320--295 & 1.7 & &1&.3 \\
\ind{Cruachan} & 0.40 & 365--334 & 11.3 & &10& \\
\ind{Foyers} & 0.30 & 178--172 & 13.6 & &6&.3 \\
\ind{Dinorwig} & 1.80 & 542--494 & 6.7 & &9&.1 \\ \bottomrule
\end{tabular}
% pr 1.7 * 9.81 * 300 / 3600
% pr 11.3 * 9.81 * 335 / 3600
% pr 13.6 * 9.81 * 172 / 3600
% pr 6.7 * 9.81 * 500 / 3600
}{
\caption[a]{Pumped\index{pumped storage} storage facilities in Britain.
The maximum energy storable in today's pumped storage systems is about 30\,GWh.
}\label{tabPS}
}
\end{table}
Pumped storage systems use cheap electricity to shove water from a downhill
lake to an uphill lake; then regenerate electricity when it's valuable,
using turbines
just like the ones in hydroelectric power stations.
\begin{figure}\small
\figuremargin{
\begin{center} \small
\begin{tabular}{rc}
\raisebox{1cm}{12 January 2006} &
\mono%
{{\epsfysize=0.62in\epsfbox{../../data/NationalGrid/0601.eps}}}%
{{\epsfysize=0.62in\epsfbox{../../data/NationalGrid/colo/0601.eps}}}
\\[0.1in]
\raisebox{1cm}{13 June 2006} & {\mbox{\epsfysize=0.62in%
\mono{\epsfbox{../../data/NationalGrid/0606.eps}}%
{\epsfbox{../../data/NationalGrid/colo/0606.eps}}%
}} \\[0.1in]
\raisebox{1cm}{9 February 2007} & {\mbox{\epsfysize=0.62in%
\mono%
{\epsfbox{../../data/NationalGrid/0702.eps}}%
{\epsfbox{../../data/NationalGrid/colo/0702.eps}}%
}}%
\\[0.05in]
& Time in hours \\
\end{tabular}
\end{center}
}{
\caption[a]{How \index{Dinorwig}pumped storage pays for itself.
Electricity prices, in \pounds\
per MWh,
on three days in 2006 and 2007.
}
\label{fig.moneyelec}
}
\end{figure}
% spot prices removed to _storage.tex
Britain has four pumped storage facilities, which
can store 30\,GWh
between them (\tabref{tabPS}, \figref{pStwlan}).
% They store energy by pumping water up from a low lake to a high lake;
% they generate electricity again on demand by letting the water back down
% through a turbine, just like a traditional hydroelectric station.
They are typically used to store excess electricity at night,
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
%\marginpar{
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/stwlan.eps}}\\
%}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Stwlan.damS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Stwlan.dam.jpg.eps}}} \\
\end{tabular}
\end{center}
\caption[a]{
% http://en.wikipedia.org/wiki/Image:Stwlan.dam.750pix.jpg
\ind{Llyn Stwlan},
the upper reservoir
% and dam
of the \ind{Ffestiniog} \ind{pumped storage}
scheme in north \ind{Wales}. Energy stored: 1.3\,GWh.
% The four water turbines at the power station can generate 360 MW of electricity within 60 seconds of the need arising.
Photo by Adrian Pingstone.
}\label{pStwlan}
}%
then return it during the day, especially at moments of peak demand --
a profitable business, as \figref{fig.moneyelec} shows.
The \ind{Dinorwig} power station
-- an astonishing cathedral inside a mountain in \ind{Snowdonia} --
also plays an insurance role: it has enough oomph to restart the
national grid in the event of a major failure.
%, underneath the mountain \ind{Elidir Fawr}
Dinorwig can switch on, from 0 to 1.3\,GW power, in 12 seconds.
Dinorwig is the Queen of the four facilities. Let's
review her vital statistics.
%% some sites say it is a 1728MW station. Indeed that's the installed capacity
%% http://www.fhc.co.uk/
%% http://www.fhc.co.uk/downloads/pdf/Increased%20Storage%20At%20Dinorwig%20Power%20Station%20-%20A%20Briefing%20Note%20For%20Consultees.pdf
The total energy that can be stored in Dinorwig is about 9\,GWh.
%% which is roughly 65\% of GB pump storage capacity
%% with the 1.4 GWh of ffestin it is roughly 75\% of GB pump storage capacity
%% source: http://209.85.135.104/search?q=cache:MR_HHbSgM3AJ:www.ipplc.com/ipplc/investors/presentations/fhsitevisit/fhvisit.pdf+dinorwig+pumped+storage&hl=en&gl=uk&ct=clnk&cd=4&client=firefox
Its upper lake is about 500\,m above the lower,
%% in fact 520m is a good mean: it goes from (92-106) lower to (600-634) upper.
%% Note the upper level drops 34 metres, and the bottom goes up by 14m.
%% it cost 425M pounds to build and took 10 yrs and employed about 1500.
%% Now it employs 150 people of whom 30 work in the building as real workers, and as few
%% as 6 will be there during night shift. The rest are administrators.
%% Tour guide said It generates for 5 hrs at 1.8GW\@.
%% pumping the water back up needs 6hrs.
%% The underground power lines cost 1 million pounds per mile.
and the working volume of 7 million m$^3$
flows at a maximum rate of 390\,m$^3$/s,
allowing power delivery at
1.7\,GW
for 5 hours.
%% that disagrees with the 1.7GW for 5 hrs statement,
%% though not hugely.
% {\myurlb{www.grownupgreen.org.uk/features/?is=131}{http://www.grownupgreen.org.uk/features/?is=131}
%% Typical prices: buy at 30 pounds / MWh, sell at 80. ??
The \ind{efficiency}\index{pumped storage!efficiency}
of this storage system is 75\%.\nlabel{DinorEff}
%% (tour guide, Dinorwig). Can replace this by graph of actual efficiency now.
%% (Dinorwig guide).
%% and http://209.85.135.104/search?q=cache:MR_HHbSgM3AJ:www.ipplc.com/ipplc/investors/presentations/fhsitevisit/fhvisit.pdf+dinorwig+pumped+storage&hl=en&gl=uk&ct=clnk&cd=4&client=firefox
%% Ffestiniog is 72% efficient and has capacity 360 MW and storage capacity 1.4GW
If all four pumped storage stations are switched on simultaneously, they
can produce a power of 2.8\,GW\@. They can switch on extremely fast,
coping with any slew rate that demand-fluctuations or wind-fluctuations
could come up with. However the capacity of 2.8\,GW
is not enough to replace 10\,GW or 33\,GW
of wind power if it suddenly went missing.
Nor is the total energy stored (30\,GWh) anywhere near the
1200\,GWh we are interested in storing in order to make it through a
big lull. Could pumped storage be ramped up?
Can we imagine solving the entire lull problem using pumped storage alone?
\subsection{Can we store 1200\,GWh?}
%% want 22GW, so if divide in 6, that is 4GW each
%% if 10, 2.2GW each.
% pr 100*3600.0 * 1000.0 / 10000.0 / 500.0
We are interested in making much bigger storage systems,
storing a total of 1200\,GWh (about 130 times what
Dinorwig stores). And we'd like the capacity to
be about 20\,GW -- about ten times bigger than Dinorwig's.
% (that's 20\,GW $\times$ 24\,hours).
% was 1000\,GWh (that's 44\,GW $\times$ 24\,hours).
% That's 120 times as much energy as Dinorwig.
So here is the pumped storage solution: we have to imagine
creating roughly 12 new sites,
each storing 100\,GWh -- roughly ten times the energy stored in Dinorwig.
% (that's 100\,GWh each).
%% 530 gigawatt hours = 1.90800 × 1015 joules
The pumping and generating hardware at each site would be the same as Dinorwig's.
Assuming the generators have an efficiency of 90\%,
\tabref{tab.pumpedstorage} shows
a few ways of storing 100\,GWh, for a range of height drops.
(For the physics behind this table, see
this chapter's endnotes.)
% e technical chapter, \pref{pstorage2}.)
{% begin troublesomepage hack
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
\begin{table}[h]\newcommand{\onecm}{\hspace*{1cm}}
\figuremargin{\small
\begin{tabular}{crr@{$\times$}l}
\toprule
\multicolumn{3}{c}{Ways to store 100\,GWh } \\
\midrule
drop from & working volume &
%% / ($10^6\,\m^3$) &
\multicolumn{2}{c}{example size} \\
upper lake & \multicolumn{1}{c}{required}
& \multicolumn{2}{c}{of lake} \\
& \multicolumn{1}{c}{(million \m$^3$)}
& \multicolumn{1}{c}{area\,} & $\!\!\!\!\!\!$ depth \\
\midrule
% 500 & 80 & 1\,\km \times 2\,\km \times 40\,\m \\ Error corrected
500\,\m & 80\onecm & $ 2\,\km^2 $ & $ 40\,\m$\\
500\,\m & 80\onecm & $ 4\,\km^2 $ & $ 20\,\m$\\
200\,\m & 200\onecm & $ 5\,\km^2 $ & $ 40\,\m$\\
200\,\m & 200\onecm & $ 10\,\km^2 $ & $ 20\,\m$\\
100\,\m & 400\onecm & $ 10\,\km^2 $ & $ 40\,\m$\\
100\,\m & 400\onecm & $ 20\,\km^2 $ & $ 20\,\m$\\
\bottomrule
\end{tabular}
}{
\caption[a]{Pumped storage.
Ways to store 100\,GWh.
% Working volumes are computed from equation (\ref{eq.Vstore}).
For comparison with column 2,
the working volume of \ind{Dinorwig} is 7 million m$^3$, and
the volume of Lake \ind{Windermere} is 300 million m$^3$.
For comparison with column 3,
% here are the areas of
% some Reservoirs:
Rutland water has an area of
% 4.86 sq mi =
12.6$\,\km^2$; Grafham water
% 2.85 sq mi. =
7.4$\,\km^2$. Carron valley reservoir
% in Scotland
% 1.51 sq mi =
is 3.9$\,\km^2$.
% (from wikipedia)
The largest lake in Great Britain
is \ind{Loch Lomond}, with an area of 71\,km$^2$.
}\label{tab.pumpedstorage}
}
\end{table}
%cf: volume of Lake Windermere = $300\times 10^6\,\m^3$.
%Reservoirs: Rutland water has an area of 4.86 sq mi = 12.6$\,\km^2$;
%Grafham water 2.85 sq mi. =7.4$\,\km^2$.
%Carron valley reservoirs in scotland 1.51 sq mi =3.9$\,\km^2$. (from wikipedia)
% \marginpar{\small 1\,square mile $= 2.6\times 10^{6}\,\m^2 = 2.6\,\km^2$}%
%
Is it plausible that twelve such sites could be found?
Certainly, we could build several more sites like Dinorwig
in Snowdonia alone. \Tabref{tab.Ffest2}\nlabel{dinorwig}
%\marginfig{
%\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/dinorwig2.eps,angle=270}}
%}
shows
%Preliminary studies by the CEGB identified 3 possible sites
%all close to Ffestiniog.
% , near to existing transmission lines.
%Bowydd, Croesor, and Dinorwig. Requirement: 1320\,MW in under 10\,s.
%Pumping daily, restricted to a 6\,h period at night.
% For Dinorwig they considered making a large lower reservoir in the Nant Ffrancon
% valley. (To the North.)
two alternative sites near to Ffestiniog where two facilities
equal to Dinorwig could have been built. These sites were considered
alongside Dinorwig in the 1970s, and Dinorwig was chosen.
%
%The alternative plans were at nearby sites
%in \ind{Snowdonia},\index{Wales} as shown in \tabref{tab.Ffest2}.
% energy stored:
% rho V g h
% in MJ
% pr 1000 * 17.7 * 9.81 * 250
% in GWh
% pr 17.7 * 9.81 * 250 / 3600
% 12.0
% pr 8.0 * 9.81 * 310 / 3600
% 6.9
\begin{table}[h]\newcommand{\onecm}{\hspace*{1cm}}
\figuremargin{\small
\begin{tabular}{lrcrr} \toprule
proposed
& power & head & \multicolumn{1}{c}{volume} & energy stored \\
%(upper reservoir, grid reference)
location
& (GW) & (m) & \multicolumn{1}{c}{(million m$^3$)} & (GWh) \\
\midrule
% SH 722 470
Bowydd
% (Llyn Newydd, SH 722 470)
& 2.40 & 250 & 17.7\onecm & 12.0 \\ % to Cwm Penmachno perhaps?
% SH 653 466
Croesor
% (Llyn Cwm-y-Foel, SH 653 466)
& 1.35 & 310 & 8.0\onecm & 6.7 \\ % to Cwm Croesor no doubt
% Plan length (m) & 1900 & 1100 \\
\bottomrule
\end{tabular}
}{\caption[a]{Alternative sites for
\ind{pumped storage} facilities in \ind{Snowdonia}.
At both these sites the lower lake would have been
a new artificial reservoir.
}
\label{tab.Ffest2}
}
\end{table}
Pumped-storage facilities holding significantly more energy than Dinorwig
could be built in Scotland by upgrading
% in many of the locations
existing hydroelectric facilities.
\begin{figure}
\figuremargin{
\begin{center}
\begin{tabular}{cc@{\,}c}
\lowres{\epsfxsize=55mm\epsfbox{../../images/OS/Dinorwig10kmS.eps}}%
{\epsfxsize=55mm\epsfbox{../../images/OS/Dinorwig10km.eps}} &
\lowres{\epsfxsize=55mm\epsfbox{../../images/OS/LochSloy10kmS.eps}}%
{\epsfxsize=55mm\epsfbox{../../images/OS/LochSloy10km.eps}} \\[0.021in]
\lowres{\epsfxsize=55mm\epsfbox{../../images/OS/DinorwigMapS.eps}}%
%{\epsfxsize=55mm\epsfbox{../../images/OS/DinorwigMap.eps}} &
{\leveltwo{\epsfxsize=55mm\epsfbox{../../images/OS/DinorwigMap.2.eps}}%
{\epsfxsize=55mm\epsfbox{../../images/OS/DinorwigMap.3.eps}}} &
\lowres{\epsfxsize=55mm\epsfbox{../../images/OS/LochSloy1S.eps}}%
{\leveltwo{\epsfxsize=55mm\epsfbox{../../images/OS/LochSloy1.2.eps}}%
{\epsfxsize=55mm\epsfbox{../../images/OS/LochSloy1.3.eps}}} \\% &
%\lowres{\epsfxsize=55mm\epsfbox{../../images/OS/LochSloy2S.eps}}%
%{\leveltwo{\epsfxsize=55mm\epsfbox{../../images/OS/LochSloy2.2.eps}}%
%{\epsfxsize=55mm\epsfbox{../../images/OS/LochSloy2.3.eps}}} \\
%% these .3.eps files are level 3 postscript.
%% to avoid problems, use level 2 postscript.
\multicolumn{1}{p{55mm}}{\lesslead
{\small{{\bf\ind{Dinorwig}} is the home of a 9\,GWh storage system, using
Marchlyn Mawr (615E,\,620N) and Llyn Peris (590E,\,598N)
as its upper and lower reservoirs.}}
}&
\multicolumn{2}{p{55mm}}{\lesslead %% was 110mm
{\small{{\bf\ind{Loch Sloy}} illustrates the sort of
location where a 40\,GWh storage system could be created. }}
}
\end{tabular}
\end{center}
}{
\caption[a]{Dinorwig, in the Snowdonia National Park, compared with
Loch Sloy and \ind{Loch Lomond}.
%% 321E 098N 2 miles between lakes
The upper maps show 10\,km by 10\,km areas.
In the lower maps the blue grid is made of 1\,km\
squares.
Images produced from Ordnance Survey's Get-a-map service
\myurlb{www.ordnancesurvey.co.uk/getamap}{http://www.ordnancesurvey.co.uk/getamap}.
Images reproduced with permission of Ordnance Survey.
\copyright\ Crown Copyright 2006.\vspace{4mm}\par
%\marginfig{
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/dinorwig.eps,angle=270}}
%}
}
\label{fig.sloy}
}
\end{figure}
Scanning a map of \ind{Scotland}, one candidate location
would use Loch Sloy as its upper lake and Loch Lomond as its
lower lake. There is already a small hydroelectric power station
% 153MW so it would take 11 days to discharge 40 GWh.
linking these lakes.
\Figref{fig.sloy} shows these lakes and the Dinorwig lakes on the same scale.
The height difference between Loch Sloy and Loch Lomond is about 270\,m.
%
% see _storage.tex
% 10m - 280m
Sloy's area is about 1.5\,km$^2$, and it can already store
an energy of
% -storage capacity is already
20\,GWh.
% source \cite{LochSloy}
If Loch Sloy's dam were raised by
another 40\,m then
% height could be pumped up by about 40\,m then
the extra energy that could be stored would be
about 40\,GWh.
% they say one inch of rain gives 1.3GWh; there is 50-fold concentration
% -- not as much as the 100\,GWh we were hoping for, .
% 40.555
% If there were no compensating flows of water in and out of
% Loch Lomond, t
The water level in Loch Lomond would change by at most
0.8\,m
% 80\,cm
during a cycle. This is less than the normal range of annual
water level variations of Loch Lomond (2\,m).
% This isn't a perfect location for a storage system, and 40\,GWh
% isn't as much as we were hoping for; if you're keen
% on wind-power, perhaps you can scour the UK maps and find
% twelve superior spots?
%
% Loch Lomond:
% http://www.ilec.or.jp/database/eur/deur28.html
% 7.9\,m 71\,km$^2$.
% Normal variation in water level: 2\,m.
% see http://www.industcards.com/hydro-scotland-n.htm
\Figref{fig.maree} shows 13 locations in Scotland
with potential for pumped storage. (Most of them already have a
hydroelectric facility.)
\begin{figure}
\figuremargin{
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/maree.eps}}
}{
\caption[a]{Lochs in Scotland with potential for pumped storage. }
\label{fig.maree}
}
\end{figure}%
% I'm not
If ten of these had the same potential as I just estimated for
Loch Sloy, then we could store 400\,GWh -- one third of the total
of 1200\,GWh that we were aiming for.\nlabel{pSloy400}
% would compensate for major lulls in wind, assuming 33\,GW of wind capacity.
% \subsection{Other storage locations}
% The most economical locations would be somewhere on the way
% from the wind-farms
% (mainly in Scotland
% to the consumers.
% (mainly in England).
We could scour the map of Britain for other locations.
The best locations would be near to big {\windfarm}s.
One idea would be to make a new artificial lake
in a hanging valley (across the mouth
of which a dam would be built) terminating above the sea,
with the sea being used as the lower lake.
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/01-Okinawa-Seawater-PSPP-lgS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/01-Okinawa-Seawater-PSPP-lg.eps}}} \\
\end{tabular}
\end{center}
\caption[a]{
\ind{Okinawa}
%seawater
pumped-storage power plant,
whose lower reservoir is the ocean.
Energy stored: 0.2\,GWh.
Photo by courtesy of \ind{J-Power}.
\myurlb{www.ieahydro.org}{http://www.ieahydro.org/}.
%Photo from \myurlb{www.ieahydro.org}{http://www.ieahydro.org/}.
%\copyright IEAHydro.
}
}
Thinking further outside the box, one could imagine
getting away from
lakes and reservoirs, putting half of the facility in an
underground chamber. A pumped-storage chamber one kilometre
below London has been mooted.
% To Do: phone someone. ***
% I've heard that it's been proposed to site a pumped-storage system's
% lower reservoir
% {\em under London}, and use the River Thames as an upper reservoir.
% (More details needed.)
% A possible advantage of using a tidal body of water as one of the
% reservoirs is the potential for a storage system to
%% actually {\em{generate}\/} a little net power,
% boost its efficiency
% by timing the pumping and generating to coincide
% -- as nearly as possible -- with low tide and high tide respectively.\label{tidal.pumped}
%%
% If the other reservoir is hundreds of metres from sea level, the
% advantage of this pumping truck
% is negligible; but in the case of a reservoir that's a few
% metres from sea-level, this trick could give a genuine energy
% benefit.
% Actually, in spite of their names,
% it might sometimes be best to have both lagoons be `high' then both be `low',
% as I'll explain.
% In conclusion,
By building more pumped storage systems, it looks as if
we could increase
our maximum energy store from 30\,GWh to 100\,GWh or perhaps 400\,GWh.
Achieving the full 1200\,GWh that we were hoping for looks tough, however.
Fortunately there is another solution.
\section{Demand management using electric vehicles}
To recap our requirements: we'd like to be able to store or
do without about 1200\,GWh, which is 20\,kWh per person;
and to cope with swings in
supply of up to 33\,GW -- that's 0.5\,kW per person.
These numbers are delightfully similar in size to the energy and
power requirements of electric cars.
The electric cars we saw in \chref{ch.transport} had
energy stores of between 9\,kWh and 53\,kWh.
A national fleet of 30 million electric cars would store an energy similar
to 20\,kWh per person!
Typical battery chargers draw a power of 2 or 3\,kW\@.
So simultaneously switching on 30 million battery chargers
would create a change in demand of about 60\,GW!
The average power required to power all the nation's transport,
if it were all electric, is roughly 40 or 50\,GW\@.
There's therefore a close match between the
adoption of electric cars proposed in \chref{ch.transport}
and the creation of roughly 33\,GW of wind capacity, delivering
10\,GW of power on average.
Here's one way this match could be exploited: electric
cars could be plugged in to smart chargers, at home or at work.
These smart chargers would be aware both of the value of electricity, and
of the car user's requirements (for example, ``my car must be fully charged
by 7am on Monday morning''). The charger would sensibly satisfy the
user's requirements by guzzling electricity whenever the wind blows,
and switching off when the wind drops, or when
other forms of demand increase.
These smart chargers would provide
a useful service in balancing to the grid, a service which could
be rewarded financially.
% The wind power would deliver on average 10\,GW, which would
% provide enough to power the
%
% If every family of two has a 20\,kWh battery, and it charges up
% overnight
We could have an especially robust solution if the cars' batteries
were exchangeable. Imagine popping in to a filling station and
slotting in a set of fresh batteries in exchange for
your exhausted batteries. The filling station would be responsible for
recharging the batteries; they could do this at the perfect times,
% -- whenever it's windy, say -- and
turning up and down their chargers
so that total supply and demand were always kept in balance.
Using exchangeable batteries is an especially robust solution because
there could be millions of spare batteries in the filling stations'
storerooms. These spare batteries would provide an extra buffer to help
us get through wind lulls.
Some people say, ``Horrors! How could I trust the filling station
to look after my batteries for me? What if they gave me a duff one?'' Well,
you could equally well ask today ``What if the filling station gave me
petrol laced with water?''
% Come on, be positive, let's trust
% professional energy suppliers to be professional, and work out a solution.
% Battery charging can be a faff.
Myself, I'd much rather use a vehicle maintained
by a professional than by a muppet like me!
Let's recap our options.
We can balance fluctuating demand and fluctuating
supply by switching on and off power {\em{generators}\/} (waste incinerators
and hydroelectric stations, for example);
by {\em{storing}\/} energy somewhere and regenerating it when it's needed;
or by switching {\em{demand}\/} off and on.
% The generators
The most promising of these options, in terms of scale, is
switching on and off the power demand of electric-vehicle charging.
30 million cars, with 40\,kWh of associated batteries each (some
of which might be exchangeable batteries sitting in filling stations)
adds up to 1200\,GWh. If freight delivery were electrified too
then the total storage capacity would be bigger still.
%% 33 GW is 10,000 windmills. 30 million vehicles, 3000 vehicles per windmill.
There is thus a beautiful match between
wind power and
electric\index{electric vehicles and wind power}
\index{wind power and electric vehicles}vehicles.
If we ramp up electric vehicles at the same time as ramping up wind power,
roughly 3000 new vehicles for every 3\,MW wind turbine,
and if we ensure that the charging systems for the vehicles are
smart, this synergy would go a long way
to solving the problem of wind fluctuations.
If my prediction about hydrogen vehicles is wrong, and hydrogen\index{hydrogen vehicles}
vehicles turn out to be the low-energy vehicles of the future,
then the
wind-with-electric-vehicles\index{hydrogen!and wind power}
match-up that I've just described could of course be replaced
by a wind-with-hydrogen match-up. The wind turbines would make electricity;
and whenever electricity was plentiful, hydrogen would be produced and stored
in tanks, for subsequent use in vehicles or in other applications, such as
glass production.\index{hydrogen!storage efficiency}
\section{Other demand-management and storage ideas}
There are a few other demand-management
and
energy-storage
options, which we'll survey now.
The idea of modifying the rate of production of stuff to match the power
of a renewable source is not new. Many aluminium production plants are
located close to hydroelectric power stations; the more it rains, the more
aluminium is produced.
Wherever power is used to create stuff that is storable,
there's potential for switching that power-demand on and off in a smart way.
For example,
\index{reverse osmosis}{reverse-osmosis} systems (which make
pure water from sea-water -- see \pref{pROdesal}) are major power consumers in many countries
(though not Britain).
Another storable product is heat.
If, as suggested in \chref{ch.smartheating}, we
electrify buildings'
heating and cooling systems, especially water-heating and
air-heating, then there's potential for lots of
easily-turn-off-and-onable power demand to be attached to the
grid. Well-insulated buildings hold their heat for many hours, so
there's flexibility in the timing of their heating.
Moreover, we could
include large thermal reservoirs in buildings,
and use heat-pumps to
pump\index{demand management}\index{electricity!demand management}
heat into or out of those reservoirs
at times of electricity abundance; then use a second set of heat pumps to deliver heat or cold from the
reservoirs to the places where heating or cooling are wanted.
Controlling electricity
\index{dynamic demand}demand automatically would be easy.
The simplest way to do this
% of delivering demand control
is to have devices such as fridges\index{refrigerators!and demand management}
and freezers listen to the
frequency of the mains.\index{electricity!mains}\index{mains electricity}
When there is a shortage of power on the grid,
the frequency drops below its standard value of 50\,Hz;
when there is a power excess, the frequency rises above 50\,Hz.
(It's just like a dynamo on a bicycle: when you switch the lights
on, you have to pedal harder to supply the extra
power; if you don't then the bike goes a bit slower.)
Fridges can be modified to nudge their internal thermostats
up and down just a little in response to the mains
frequency\nlabel{pFridge}, in such a way that, without ever
jeopardizing the temperature of your butter, they tend to
take power at times that help the grid.
Can demand-management provide
a significant chunk of virtual storage?
How big a sink of power are the nation's fridges?
On average, a typical fridge-freezer draws about 18\,W;
let's guess that the number of fridges is about 30\,million.
So the ability to switch off all the nation's fridges for a
few minutes would be equivalent to 0.54\,GW of automatic adjustable
power.
This is quite a lot of electrical power -- more than 1\% of the
national total -- and it is similar in size to the
sudden increases in demand produced when the people,
united in an act of religious observance (such as
watching \index{Coronation Street}\ind{EastEnders}),
simultaneously switch on their
% half a million
kettles. Such
``\ind{TV pick-ups}''\index{pick-ups}
typically produce increases of demand of 0.6--0.8\,GW\@.
%% http://www.nationalgrid.com/uk/Media+Centre/worldcup/releases/09-06-06.htm
%% Top 10 TV-pickups
%
% 1. 4 July 1990
% World Cup Semi-final (West Germany v England) 2,800MW
% 2. 22 January 1984
% The Thornbirds 2,600MW
% 3. 21 June 2002
% World Cup (England v Brazil) 2,570MW
% 4. 12 June 2002
% World Cup (Nigeria v England) 2,340MW
% 5. 5 April 2001
% Eastenders (Who shot Phil Mitchell) 2,290MW
% 6. 8 May 1985
% Dallas (Who shot JR) 2,200MW
% 7. 20 April 1991
% The Darling Buds of May 2,200MW
% 8. 22 November 2003
% Rugby World Cup Final (England v Australia) 2,110MW
% 9. 18 April 1994
% Coronation Street 2,100MW
% 10. 3 June 1998
% World Cup (England v Argentina) 2,100MW
% It would be
%% http://www.nationalgrid.com/uk/Media+Centre/worldcup/
% Popular soap operas such as
% \ind{Coronation Street} and
% \ind{EastEnders} typically generate TV pick-ups of 0.6--0.8\,GW\@.
Automatically switching off every fridge would {\em{nearly}\/}
cover these daily blips of concerted \ind{kettle} boiling.
These smart fridges could also help iron out short-time-scale
fluctuations in wind power.
The TV pick-ups associated with the holiest acts\index{religion}
of observance
(for example, watching England play footie\index{football}
against Sweden)
can produce sudden increases in demand
of over 2\,GW\@. On such occasions, electricity
demand and supply are kept in balance by unleashing
the full might of Dinorwig.
To provide flexibility to the electricity-grid's managers,
who perpetually turn power stations
up and down to match supply to demand, many industrial
users of electricity are on special contracts that allow
the managers to switch off those users'
demand at very short notice.
%
In \ind{South Africa} (where there are frequent electricity shortages),
radio-controlled \index{demand management}demand-management systems are being installed
in hundreds of thousands of homes, to control
air-condition\-ing systems and
electric water heaters.\label{pSAE}
% Fluctuations in wind power will be a different matter.
%\section{Other solutions}
% http://www.energinet.dk/en/menu/Frontpage.htm#
% cool danish site has live export display
\subsection{Denmark's solution}
Here's how \ind{Denmark} copes with the intermittency of its
wind power. The Danes effectively pay to
use other countries' hydroelectric facilities
as storage facilities.
Almost all of Denmark's wind power is exported to its European neighbours,
some of whom have hydroelectric power, which they can turn down to
balance things out. The saved hydroelectric power is then
sold back to the Danes (at a higher price) during the next
period of low wind and high demand.
% Thus the other countries' hydroelectric facilities are effectively
% being used as a storage facility for Denmark.
Overall, Danish wind
is contributing useful energy, and the system as a whole has considerable
security thanks to the capacity of the hydro system.
Could Britain adopt the Danish solution?
We would need direct large-capacity connections
to countries with lots of turn-off-and-on-able
hydroelectric capacity; or a big connection to
a Europe-wide electricity grid.
\ind{Norway} has 27.5\,GW of hydroelectric capacity. \ind{Sweden} has roughly
16\,GW\@. And \ind{Iceland} has 1.8\,GW\@.
% 120 TWh per year
% load factor 0.49
A 1.2\,GW high-voltage DC interconnector\index{interconnector!Norway}
to Norway was mooted in 2003, but not built.
% In 2003 National Grid and Statnett (the Norwegian grid operator) obtained environmental permits for a 1200MW interconnector between Easington, County Durham, and Suldal in Rogaland County.
% http://www.nationalgrid.com/uk/Interconnectors/Norway/
% Purpose 10% of the Norwegian electricity load in what is described as a typical ???dry??? Norwegian
% The length would be 750 KM and the cost was approximately 700 million GBP. Had
% plans were finally rejected by Norwegian authorities in September 2003.
% Iceland has 1.8\,GW\@.
% 81% of all elec is from hydro there.
% 690+150+270+210+28+150+89+120+90
% 690MW of which is under construction
% http://www.nationalgrid.com/uk/Interconnectors/Netherlands/
A connection to the Netherlands -- the \ind{BritNed} interconnector, with a capacity of 1\,GW --
will be built in 2010.
% 260km long, 600M euro cost.
% An Ireland-Wales interconnector (500 MW) is mooted 2001.
Denmark's wind capacity is 3.1\,GW, and it has a 1\,GW connection to Norway, 0.6\,GW to
Sweden, and 1.2\,GW to Germany, a total export capacity of 2.8\,GW, very similar to
its wind capacity.\nlabel{DenmarkW}
% http://www.statnett.no/default.aspx?ChannelID=1182
% excellent document:
% url={http://incoteco.com/upload/CIEN.158.2.66.pdf}
To be able to export all its excess wind power in the
style of Denmark, Britain (assuming 33\,GW of wind capacity)
would need something like
a 10\,GW connection to
Norway, 8\,GW to
Sweden, and 1\,GW to Iceland.
% Norway uses 112.8 Billion KWH (2004) ie average ie 12.9GW
% Sweden Electricity - Consumption: 137.8 Billion KWH (2004) ie 15.7GW average
\subsection{A solution with two grids}
A radical approach is to
put wind power and other intermittent sources onto
a separate
{\em{second}\/} \index{electricity!grid}{electricity grid},
used to power systems that
\amarginfig{b}{
% \begin{figure}
\begin{center}
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/fairisle.eps}}\\
\par\small
\begin{tabular}{lr}
{\sc Production} & {\sc Consumption} \\
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.821}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Electrical production and consumption on \ind{Fair Isle}, 1995--96.
All numbers are in kWh/d per person.
Production exceeds consumption because 0.6\,kWh/d per person were dumped.
}
\label{fairi}
\label{fairisle}
}%
% \end{figure}
don't require reliable power, such as heating and \ind{electric vehicle}
\index{battery charging}{battery-charging}.\index{charging, electric vehicle}
For over 25 years (since 1982),\nlabel{pFairIsle}
the Scottish island of \ind{Fair Isle} (population 70, area 5.6\,km$^2$)
has had {\em{two}\/} electricity networks that distribute
power from two wind turbines
%% nominal 60kW and 100kW
and, if necessary,
a diesel-powered electricity generator.
Standard electricity service is provided on
one network, and electric heating is delivered by a
second set of cables. The electric heating is mainly
served by excess electricity from the wind-turbines that would otherwise
have had to be dumped.
Remote frequency-sensitive programmable relays
control individual water heaters and
storage heaters in the individual buildings of the community.
The mains frequency is used to inform heaters when they may switch on.
In fact there are up to six frequency channels per household,
so the system emulates seven grids.
Fair Isle also successfully trialled a
\ind{kinetic-energy storage}
\index{storage!kinetic energy}
system (a \ind{flywheel}) to store energy during\index{Scotland}
fluctuations of wind strength on a time-scale of 20 seconds.
% (with a period of 12 to 20 seconds).
%
% Amounts of electrical energy delivered:
% 42.3 MWh from the diesel.
% 444+293 MWh from the two turbines
% of which 182 were dumped.
\subsection{Electrical vehicles as generators}
% for grid stability}
%Vehicle-to-grid power.
%% http://www.udel.edu/V2G/
%% http://www.udel.edu/V2G/
%%http://www.acpropulsion.com/
%%http://www.acpropulsion.com/
%% see also http://www.stefanoparis.com/piaev/piaev.html
If 30 million electric vehicles were willing, in times of
national electricity shortage,\index{vehicle to grid}
to run their chargers
in reverse and put power back into the grid, then, at 2\,kW per
vehicle, we'd have a potential power source of 60\,GW -- similar
to the capacity of all the power stations in the country.
Even if only one third of the vehicles were connected and
available at one time, they'd still amount to a potential source
of 20\,GW of power.
If each of those vehicles made an emergency donation of
% were willing, in emergencies, to share
2\,kWh of energy --
corresponding to perhaps 20\% of its battery's energy-storage capacity --
then the total energy provided by the fleet would be 20\,GWh --
twice as much as the energy in the Dinorwig pumped storage
facility.
\subsection{Other storage technologies}
There are lots of ways to store energy, and lots of criteria
by which storage solutions are judged.
\Figref{fig.batteriesFuels} shows three of the most important criteria:
energy density (how much energy is stored per kilogram
of storage system);
efficiency (how much energy you get back per unit
energy put in); and lifetime (how many cycles of
energy storage can be delivered before the system needs
refurbishing).
Other important criteria are: the maximum rate at which
energy can be pumped into or out of the storage system,
often expressed as a power per kg; the duration for which
energy stays stored in the system; and of course
the cost and safety of the system.
\begin{figure}\small
\figuremargin{\small
\begin{center}
\begin{tabular}{@{}cc}
\mbox{\epsfxsize=56.4mm%
\mono{\epsfbox{../data/mono/storage1.eps}}%
{\epsfbox{../data/storage1.eps}}%
}&
\mbox{\epsfxsize=56.4mm%
\mono{\epsfbox{../data/mono/storage2.eps}}%
{\epsfbox{../data/storage2.eps}}%
}%
\\
(a)&(b)
\\
\end{tabular}
\end{center}
}{
\caption[a]{Some properties of storage systems and fuels.
(a) Energy density (on a logarithmic scale)
versus lifetime (number of cycles).
(b) Energy density versus efficiency.
The energy densities don't include the masses of
the energy systems' containers, except in the case of ``air''
(compressed air storage).
Taking into account the weight of a cryogenic tank
for holding hydrogen, the energy density of hydrogen is reduced
% missing ``from'' ?
from
39\,000\,Wh/kg to
roughly 2400\,Wh/kg. % electriccar.tex
% The lifetimes for vanadium flow batteries
% and pumped storage are only indicative.
% The efficiency of compressed air storage is a guess,
% as I was not able to find published data.
}
\label{fig.batteriesFuels}
}
\end{figure}
\begin{table}
\figuremargin{\small
\begin{tabular}[t]{cc}
\begin{tabular}[b]{lrl} \toprule %%% HHVs
fuel &\multicolumn{2}{l}{calorific value} \\ \midrule
&(kWh/kg) &(MJ/l) \\ \midrule
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
propane &13.8 &25.4 \\
petrol
% (automotive gasoline)
& 13.0 & 34.7 \\ % 47.1 GJ per tonne and 1357l/tonne 13083
% CO2: 2.344 kg per litre (motor spirit)
diesel oil (DERV) & 12.7 & 37.9 \\ % 45.6 GJ per tonne and 1203 l/tonne
% CO2: 2.682 kg per litre
kerosene &12.8 &37 \\
heating oil &12.8 &37.3 \\
ethanol & 8.2 &23.4\\ %% HHV 23.512\,MJ/l, LHV 22.778\,MJ/l.
methanol & 5.5 &18.0\\ % HHV is 18.0\,MJ/l. from wikipedia LHV:15.8MJ/l
bioethanol & & 21.6 \\ % added Sun 3/8/08, source unsure, maybe \cite{RisoBiofuels}
coal & 8.0 & \\
%% Coal 26.7 GJ/tonne gross cal value
%Energy in air-seasoned
firewood &4.4\\ % 10-20 GJ per tonne
hydrogen &39.0 \\
natural gas &14.85 & 0.04 \\ % IPCC %Heat of combustion (LHV) 48.252 MJ kg-1 %Heat of combustion (HHV) 53.463 MJ kg-1 % and 200 g COO per kWh
% Natural gas 39.6 MJ/cubic metre
% LPG & & 25.2\\
\bottomrule
\end{tabular}%
\index{fuel!energy density}\index{fuel!calorific value}%
\index{energy density!fuel}\index{calorific value!fuel}%
\index{diesel!energy density}\index{diesel!calorific value}%
\index{energy density!diesel}\index{calorific value!diesel}%
\index{DERV!energy density}\index{DERV!calorific value}%
\index{energy density!DERV}\index{calorific value!DERV}%
\index{propane!energy density}\index{propane!calorific value}%
\index{energy density!propane}\index{calorific value!propane}%
\index{firewood!energy density}\index{firewood!calorific value}%
\index{energy density!firewood}\index{calorific value!firewood}%
\index{kerosene!energy density}\index{kerosene!calorific value}%
\index{energy density!kerosene}\index{calorific value!kerosene}%
\index{coal!energy density}\index{coal!calorific value}%
\index{energy density!coal}\index{calorific value!coal}%
\index{methanol!energy density}\index{methanol!calorific value}%
\index{energy density!methanol}\index{calorific value!methanol}%
\index{ethanol!energy density}\index{ethanol!calorific value}%
\index{energy density!ethanol}\index{calorific value!ethanol}%
\index{hydrogen!energy density}\index{hydrogen!calorific value}%
\index{energy density!hydrogen}\index{calorific value!hydrogen}%
&
\begin{tabular}[b]{l*{3}{r@{}c@{}l}c} \toprule
battery type & \multicolumn{3}{c}{\hspace*{-5mm}energy density} & lifetime \\
& \multicolumn{3}{c}{(Wh/kg)} & \multicolumn{3}{c}{(cycles)}
\\ \midrule
%% Cycle life is to 80\% initial capacity\\
nickel-cadmium &45&--&80 &1500\\
NiMH &60&--&120 &300--500\\
lead-acid &30&--&50 &200--300\\
lithium-ion &110&--&160 &300--500\\
lithium-ion-polymer
&100&--&130 &300--500\\
reusable alkaline& \multicolumn{3}{c}{80\,\,\,\,\,} & 50 \\
%% (initially) (to 50\% capacity)
%% see electricar from lithiumphosphate info; 84 Wh/kg
\bottomrule
\end{tabular}
\\
(a)&(b)
\\
\end{tabular}
}{
\caption[a]{
(a) Calorific values (energy densities, per kg
and per litre) of some fuels (in kWh per kg and MJ per litre).
\par
(b) Energy density of some batteries (in Wh per kg).
1\,kWh = 1000\,Wh.
\index{lithium-ion battery!energy density}%
\index{lithium-ion polymer battery!energy density}%
\index{alkaline battery!energy density}%
\index{nickel metal hydride battery!energy density}%
\index{nickel cadmium battery!energy density}%
\index{lead-acid battery!energy density}%
\index{battery!energy density}%
\index{energy density!lead-acid battery}%
\index{energy density!lithium-ion battery}%
}\label{pFuels}
}
\end{table}
%flammable fuels typically provide around 10\,MJ/kg
%while batteries yield less than 0.5\,MJ/kg.
\subsubsection{Flywheels}
\Figref{JETfly} shows a monster flywheel
used to supply brief bursts of power of up to 0.4\,GW to
power an experimental facility.
It weighs 800\,t.
Spinning at 225 revolutions per minute,
it can store 1000\,kWh, and its energy density is about 1\,Wh
per kg.%
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/flywheel_constr.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{One of the two \index{JET}flywheels
at the fusion research facility in Culham,
under construction.
Photo: EFDA-JET\@. \myurl{www.jet.efda.org}.%{http://www.jet.efda.org/}
}\label{JETfly}
}
% http://www.flybridsystems.com/F1System.html
A flywheel system designed for energy storage
in a racing car can store 400\,kJ (0.1\,kWh) of
energy and weighs 24\,kg (\pref{fig.flybrid}).
% including its continuously variable transmission
That's an energy density of
% 400 kJ / 24 in Wh 60,000 rpm
4.6\,\Wh\ per kg.
% and can do pwer of 60 kW in either direction
% \myurl{http://www.flybridsystems.com/F1System.html}
% {FlynnWheel
% describe a rotor for a bus of mass 58.2kg, which at 40,000 rpm
% stores 1.93 kWh (33 Wh per kg of rotor)
% http://www.freepatentsonline.com/EP1060337.html
% The present invention is directed to a flywheel which is capable of storing large amounts of energy and achieving high energy density as for example as much as 500 kJ (140 watt hour) kilogram.
%% http://en.wikipedia.org/wiki/Flywheel_energy_storage
% The fusion research facility at Culham has two
% eight-hundred-ton flywheels
% for energy storage.
% http://www.jet.efda.org/pages/focus/power/index.html
% each JET experiment requires 10GJ which is 2.8 MWh
% I inertia is 13.5 million kg.m2
% max speed at rim 380 km/h 3.75Hz
% When spinning at 225 revolutions per minute, the total energy
% in one flywheel is 1\,MWh.
% 1.04
% 13.5 million kg (m ** 2) * ((3.75 Hz * 2 * Pi) ** 2) * 0.5 = 1.04093484 megawatt hours
% Each flywheel generator is capable of providing 3750 MJ of energy for the JET pulsed power systems, with a maximum of 400 MW power output.
% http://www.jet.efda.org/pages/focus/power/images/flywheel_constr.jpg
% That is 1.3\,Wh/kg
High-speed flywheels made of composite materials
have energy densities up to 100\,Wh/kg.
% source page 9 of \citet{RuddellFly}
\subsubsection{Supercapacitors}
Supercapacitors are used to store small amounts
of electrical energy (up to 1\,kWh)
where many cycles of operation are required, and charging
must be completed quickly.
% 5000 Farads millions of cycles
% Maxwell Technologies rated at 6 Wh/kg.
For example, supercapacitors are favoured over batteries for
regenerative braking in vehicles that do many stops and starts.
You can buy supercapacitors with an energy density of 6\,Wh/kg.
% http://www.treehugger.com/files/2006/03/eestor_capacito_1.php
A US company, \ind{EEStor}, claims to
% parallel plate capacitor with barium titanate as the dielectric
be able to make much better supercapacitors,
using \ind{barium titanate},
% as the dielectric,
with an energy density of 280\,Wh/kg.
% nothing at--
% http://eestor.us/
% http://forums.macrumors.com/showthread.php?t=274232
% MIT:
% http://www.techreview.com/Biztech/18086/page1/
% http://en.wikipedia.org/wiki/Supercapacitor
% says 342 Wh/kg and 95% efficient
%Claim: 280 watt hours per kilogram, compared with around 120 watt
%hours per kilogram for lithium-ion and 32 watt hours per kilogram for
%lead-acid gel batteries.
\subsubsection{Vanadium flow batteries}
\ind{VRB power systems}\nlabel{pVanad}
have provided a 12\,MWh energy storage system
for the Sorne Hill {\windfarm} in Ireland, whose current
capacity is ``32\,MW,'' increasing
to ``39\,MW\@.''
(VRB stands for vanadium redox battery.)
% \tinyurl{ktd7a}{http://www.vrbpower.com/docs/news/2006/20060830\%20-\%20PR\%20-\%20Tapbury\%20Sale\%20-\%20Ireland\%20Windfarm.pdf}
This storage system is a big ``flow battery,''
a redox regenerative fuel cell, with a couple of
% vanadium-based
tanks full of vanadium in different chemical states.
This storage system can smooth the output of its {\windfarm} on a time-scale of
minutes, but the longest time for which it could deliver one third of the
capacity (during a lull in the wind) is one hour.
% The same company installed a 1.1\,MWh system on Tasmania.
% It can deliver 200\,kW for four hours, 300\,kW for 5 minutes and 400\,kW for
% 10 seconds.
A 1.5\,MWh vanadium system costing \$480\,000
occupies 70\,m$^2$ with a mass of 107 {\tonnes}.
% Energy density in Wh/litre:
% Lead acid 12--18;
% (70 in theory)
% VRB 16--33.
% Efficiency: lead acid 45\%, VRB
The vanadium redox battery
% flowbattery
has a life of more than 10\,000 cycles.
It can be charged at the same rate that it is discharged (in contrast to
lead-acid batteries which must be charged 5 times as slowly).
% \tinyurl{627ced}{http://www.vrbpower.com/docs/whitepapers/SEItechpaper1.pdf}
Its efficiency is 70--75\%, round-trip.
The volume required is about 1\,m$^3$
of 2-molar vanadium in sulphuric acid
to store 20\,kWh.
% (That's 0.02\,kWh/kg or 72\,kJ/kg.)
(That's 20\,Wh/kg.)
So to store 10\,GWh would require
500\,000\,m$^3$ (170 swimming pools)
-- for example, tanks 2\,m high
covering a floor area of
500\,m $\times$ 500\,m.
Scaling up the vanadium technology to match a big
% the scale of
pumped-storage
system --
10\,GWh -- might have a noticeable effect on the world vanadium
market, but there is no long-term shortage of vanadium.
Current worldwide production of
vanadium is 40\,000 {\tonnes} per year.
% \tinyurl{5fasl7}{http://www.indexmundi.com/en/commodities/minerals/vanadium/vanadium_t7.html}.
% atomic mass 51.
A 10\,GWh system
% , assuming 1-molar vanadium solution,
would contain 36\,000 {\tonnes} of vanadium -- about
one year's worth of current production.
Vanadium is currently produced as a by-product of other processes,
and the total world vanadium resource is estimated to be 63\,million \tonnes.
\subsection{``Economical'' solutions}
In the present world which doesn't put any cost
on carbon pollution,
the financial bar that a storage system must beat is
an ugly alternative: storage can be emulated by
simply putting up an extra gas-fired power station to meet
extra demand,
and shedding any excess electrical power by throwing
it away in heaters.
% Gas stations cost \pounds 475 per kW to build, or
% \pounds 475 million per GW\@.
% Dinorwig spends much of the day running two of its six generators,
% that is, it delivers 600\,MW; this power-delivery could be
% emulated by \pounds285-million-worth of gas power station.
\section{Seasonal fluctuations}
The fluctuations of supply and demand that have the longest timescale
are seasonal. The most important fluctuation is
that of building-heating, which goes up every winter.
% from aplan.tex
Current UK natural gas demand varies\index{natural gas!demand varies}
throughout the year, from a typical average of\index{energy demand variations}
36\,kWh/d per person
% 90\,GW (36\,kWh/d per person)
in July and August
% 2002
to an average of
72\,kWh/d per person
% 180\,GW
in December to February,
with extremes of
30--80\,kWh/d/p (\figref{fig.gasdemand2}).
% 75--200\,GW\@.
\marginfig{
\begin{center}
\begin{tabular}{@{}c}
\mbox{\epsfxsize=53mm%
{\epsfbox{../../data/UKgas/demand07.eps}}%
}
\\
\end{tabular}
\end{center}
% }{ UKgas/gnud2
\caption[a]{Gas demand (lower graph)
and temperature (upper graph) in Britain during 2007.\index{data!gas demand}\index{natural gas!national demand}%
\index{gas!national demand}\index{national gas demand}\index{demand!gas}
}
\label{fig.gasdemand2}
}
Some renewables also have yearly
fluctuations -- solar power is stronger in summer
and wind power is weaker.
% Unfortunately, that's back to front
% compared with the demand!
How to ride through these very-long-timescale fluctuations?
Electric vehicles and pumped storage are not going to help store
the sort of quantities required.
A useful technology will surely be long-term thermal storage.
A big rock or a big vat of water can store a winter's worth of heat for a building --
\chref{ch.heating2} discusses this idea in more detail.
% Dutch roads
In the \ind{Netherlands},
summer heat from roads is
stored in aquifers until the winter; and delivered
to buildings via heat pumps\nlabel{Dutchroad}
\tinyurl{2wmuw7}{http://news.yahoo.com/s/ap/20071231/ap_on_hi_te/solar_roads;_ylt=AuEFouXxz16nP8MRlInTJMms0NUE}.
}% end of troublesome figures hack
\section{Notes}
\small
\beforenotelist
%\begin{widenotelist}
\begin{notelist}
\item[page no.]
\item[\npageref{pEireWi}]
{\nqs{ The total output of
the wind fleet of the Republic of \ind{Ireland}}.}
% \par
Data from {\tt{eirgrid.com}}
\tinyurl{2hxf6c}{http://www.eirgrid.com/EirGridPortal/DesktopDefault.aspx?tabid=Wind Generation Curve&TreeLinkModID=1451&TreeLinkItemID=247}.
\item[\npageref{texaswind}]
{\nqs{``Loss of wind causes \ind{Texas}
power grid emergency''}.}
\tinyurl{2l99ht}{http://www.reuters.com/article/domesticNews/idUSN2749522920080228}
Actually, my reading of this news article is that this event, albeit
unusual, was an example of {\em{normal}\/} power grid
operation. The grid has industrial customers whose supply is
interruptible, in the event of a
mismatch between supply and demand.
Wind output dropped by 1.4\,GW
at the same time that Texans' demand
increased by 4.4\,GW, causing exactly such a
mismatch between supply and demand.
The interruptible supplies were interrupted.
Everything worked as intended.
%
%% expected drop in wind was 1GW but it dropped by 1.4
%% see also
%% http://dallas.bizjournals.com/dallas/stories/2008/02/25/daily37.html?jst=b_ln_hl
%
%\end{widenotelist}
%\begin{notelist}
%\item[]
Here is another example, where better power-system
planning would have helped:
``Spain wind power hits record, cut ordered.''
\tinyurl{3x2kvv}{http://www.reuters.com/article/rbssIndustryMaterialsUtilitiesNews/idUSL057816620080305}
Spain's average electricity consumption is 31\,GW\@.
On Tuesday 4th March 2008, its wind generators were delivering
% population 40.4 M
10\,GW\@. ``Spain's\index{wind!Spain}\index{Spain!wind}
power market has become particularly sensitive to fluctuations in wind.''
\item[\npageref{pWindIntNoProb}]
{\nqs{ Supporters of wind energy
play down this problem: ``Don't worry --
individual {\windfarm}s may be intermittent, but taken
together, the sum of all {\windfarm}s is much less intermittent.''}}
For an example,
see
% In fact, some people play down the problem to an outrageous degree:
the website \url{yes2wind.com}, which, on its page ``debunking the myth
that wind power isn't reliable'' asserts that\index{myth!wind reliability}
``the variation in output from wind
farms distributed around the country is scarcely noticeable.''
\myurlb{www.yes2wind.com/intermittency_debunk.html}{http://www.yes2wind.com/intermittency_debunk.html}
\item[\npageref{pOswald}]
{\nqs{\ldots wind {\bf{is}} intermittent, even if we add up lots of
turbines covering a whole country.
The \UK\ is a bit larger than \ind{Ireland}, but the same problem
holds there too}}. Source:
\cite{OswaldWindSmoothing}.
\item[\npageref{DinorEff}]
{\nqs{Dinorwig's pumped-storage \ind{efficiency}\index{pumped storage!efficiency}
is 75\%}}.
\Figref{fig.pumped} shows data.
Further information about Dinorwig and the alternate
sites for pumped storage: \cite{Dinorwig8739,DinorwigDiscussion}.%
\marginfig{
\begin{center}
\begin{tabular}{@{}c}
\mbox{\epsfxsize=53mm%
{\epsfbox{../../data/UKgas/pumped.eps}}%
}
%% gnupumpedps
\\
\end{tabular}
\end{center}
% }{
\caption[a]{Efficiency of the four
pumped storage systems of Britain.\index{data!pumped storage}
}
\label{fig.pumped}
}
\item[\npageref{tab.pumpedstorage}]
{\nqs{\Tabref{tab.pumpedstorage}.}}
The working volume required, $V$, is computed from the height drop $h$ as
follows. If $\epsilon$ is the efficiency of
potential energy to electricity conversion,
%
% $ \epsilon \rho V g h = 50\, \GWh $
%
% was 100
\[%beq
V = 100\,\GWh / (\rho g h \epsilon) ,
\label{eq.Vstore}
\]%eeq
where $\rho$ is the density of water and $g$ is the
acceleration of gravity.
I assumed the generators have an efficiency
of $\epsilon = 0.9$.
\setcounter{latestnotepage}{0}
\item[\npageref{tab.Ffest2}]
{\nqs{\Tabref{tab.Ffest2}}}, {\nqs{Alternative sites for
pumped storage facilities}}.
The proposed upper reservoir
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/dinorwig2.eps}}\\
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Croesor2S.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Croesor2.jpg.eps}}} \\
\end{tabular}
\end{center}
\caption[a]{
A possible site for another 7\,GWh pumped storage facility.
\ind{Croesor} valley is in the centre-left,
between the sharp peak (Cnicht) on the left
and the broader peaks (the Moelwyns) on the right.
}
\label{Croesorimage}
}%
for
Bowydd was Llyn Newydd, grid reference SH 722 470;
for Croesor: Llyn Cwm-y-Foel, SH 653 466.
\item[\npageref{pSloy400}]
{\nqs{If ten Scottish pumped storage facilities
had the same potential as
Loch Sloy, then we could store 400\,GWh.}}
This rough estimate is backed up by a study
by \ind{Strathclyde University}
\tinyurl{5o2xgu}{http://www.esru.strath.ac.uk/EandE/Web_sites/03-04/wind/content/storage available.html}
which lists 14 sites having an estimated storage capacity of
514\,GWh.
\item[\npageref{pFridge}]
{\nqs{Fridges can be modified to nudge their internal thermostats
up and down \ldots\ in response to the mains
frequency}}.
\tinyurl{2n3pmb}{http://www.dynamicdemand.co.uk/pdf_fridge_test.pdf}
Further links:
\ind{Dynamic Demand}
\myurlb{www.dynamicdemand.co.uk}{http://www.dynamicdemand.co.uk/};
\myurlb{www.rltec.com}{http://www.rltec.com/};
% , a non-profit organization,
% promotes the introduction of
% {\ind{dynamic demand control}}
% technologies on the UK power grid by advocating
% institutional change and stimulating research and discussion.
%%
%% fridge that listens to the frequency
%% nice meter displaying the frequency http://www.dynamicdemand.co.uk/grid.htm
\myurlb{www.responsiveload.com}{http://www.responsiveload.com/}.
\item[\npageref{pSAE}]
{\nqs{In South Africa \ldots\
demand-management systems are being installed}}.\par
Source:
\tinyurl{2k8h4o}{http://www.int.iol.co.za/index.php?art_id=vn20080201045821205C890035}
\item[\npageref{DenmarkW}]
{\nqs{Almost all of Denmark's wind power is exported to its European neighbours.}}
% url={http://incoteco.com/upload/CIEN.158.2.66.pdf}
Source: \cite{SharmanDK}.
\item[\npageref{pFairIsle}]
{\nqs{For over 25 years (since 1982), Fair Isle
has had {\em{two}\/} electricity networks}.}
\par
\myurlb{www.fairisle.org.uk/FIECo/}{http://www.fairisle.org.uk/FIECo/}
% \myurl{http://www.fairisle.org.uk/FIECo/renewed/fig_1_2.htm}
% \myurl{http://www.fairisle.org.uk/FIECo/renewables_obligations.htm}
% \myurl{http://www.fairisle.org.uk/FIECo/index.htm}
% \myurl{http://www.fairisle.org.uk/FIECo/renewed/1982-1996.htm}
Wind speeds are between 3\,m/s and 16\,m/s most of the time;
7\,m/s is the most probable speed.
% Energy totals 1995--96 (MWh):
% In: Diesel = 47, Wind = 106.
% Out: Dump = 16, Demand = 74, Heating = 63.
% Special requirement: every dwelling has two power lines to it,
% and smart hardware controlling the power to various appliances.
% Comparable: every house getting a cable television connection.
\item[\npageref{fig.batteriesFuels}] {\nqs{\Figref{fig.batteriesFuels}}}.
{\nqs{Storage efficiencies}}.
%
Lithium-ion batteries: 88\% efficient.
\par
Source:
% Linear Technology
\myurlb{www.national.com/appinfo/power/files/swcap_eet.pdf}{http://www.national.com/appinfo/power/files/swcap_eet.pdf}
% Paper says 88\% efficient (over the usable charge-discharge range)
Lead-acid batteries: 85--95\%.
\par
% Arizona Wind and Sun
Source:
\myurlb{www.windsun.com/Batteries/Battery_FAQ.htm}{http://www.windsun.com/Batteries/Battery_FAQ.htm}
% `Typical efficiency in a lead-acid battery is 85--95\%.'%
\index{battery!efficiency}%
\index{lead-acid battery!efficiency}%
\index{lithium-ion battery!efficiency}%
% hydraulic motor shown with efficiency up to 94\%
Compressed air storage: 18\% efficient. Source: \cite{EnergyStoreCompare,EnergyStoreThesis}. See also \cite{citeulike:998687}.
\end{notelist}
\begin{widenotelist}
\item[]
Air/oil:
hydraulic accumulators, as used for regenerative
braking in trucks, are compressed-air storage devices
that can be 90\%-efficient round-trip
and allow 70\% of
kinetic energy to be captured.
Sources: \cite{EnergyStoreThesis},
\tinyurlb{5cp27j}{http://www.eaton.com/EatonCom/ProductsServices/Hybrid/SystemsOverview/HydraulicHLA/index.htm}.
\item[\npageref{pFuels}]
{\nqs{\Tabref{pFuels}}}.
Sources: Xtronics
\myurlb{xtronics.com/reference/energy_density.htm}{http://xtronics.com/reference/energy_density.htm};
Battery University
\tinyurl{2sxlyj}{http://www.batteryuniversity.com/partone-3.htm};
% \myurl{http://www.batteryuniversity.com/}; \par
%
flywheel information from \citet{RuddellFly}.
% \citet{flywheelKWH}.
% wikipedia \myurl{http://en.wikipedia.org/wiki/Flywheel_energy_storage}.
The latest batteries with highest energy density are
\ind{lithium-sulphur} and lithium-sulphide batteries\index{battery!lithium-sulphur},
which have an energy density of 300\,Wh/kg.
% http://peswiki.com/index.php/Directory:Lithium_Sulphur_Batteries
% made by http://www.oxisenergy.com/ who say lithium sulphide is better
% sion power AZ
% and http://www.polyplus.com/
% Oxis say their number of cycles is 150-200 works at high temperature.
% and 360 Wh/kg? No, 250Wh/kg
% specific energy is what people normally call my energy density
%% modern power grids have well established mechanisms
%% to deal with this intermittency (spinning reserve, frequency controlled
%% disconnectable load shedding, special tariffs to promote load deferral or
%% advancement etc).
Some disillusioned hydrogen-enthusiasts seem to be
making their way up the periodic table and becoming
% getting excited about boron.
\ind{boron}-enthusiasts. Boron (assuming you will burn it to B$_2$O$_3$)
has an energy density of 15\,000\,Wh per kg, which is nice and high.
But I imagine that my main concern about hydrogen will apply to boron too:
that the production of the fuel (here, boron from boron oxide) will be inefficient
in energy terms,\index{hydrogen!and boron}
and so will the combustion process.
% 1e3 MJ / 18.3 kg
% 1e3 / 18.3 / 3.6 = 15kWh per kg
% Boron 18.3\,kg B and 40.62 kg of oxygen per GJ (making 58.92 kg of ash)
% Boron for 1GJ occupies 7.82 litres and the ash occupies 23.1litres.
% B(s) + (3/4)O2 makes (1/2)B2O3(gls) -590.76 kJ/mol
% (and there's an extra cost of something like 10kJ/mol for practical oxygen purification)
% http://www.eagle.ca/~gcowan/boron_blast.html#TOC
% 1GJ for 300km range
\item[\npageref{pVanad}]
{\nqs{Vanadium flow batteries.}}
Sources:
\myurlb{www.vrbpower.com}{http://www.vrbpower.com/index.html};
{\nqs{Ireland {\windfarm}}}
\tinyurl{ktd7a}{http://www.vrbpower.com/docs/news/2006/20060830 - PR - Tapbury Sale - Ireland Windfarm.pdf};
{\nqs{charging rate}}
\tinyurl{627ced}{http://www.vrbpower.com/docs/whitepapers/SEItechpaper1.pdf};
{\nqs{worldwide production}}
\tinyurl{5fasl7}{http://www.indexmundi.com/en/commodities/minerals/vanadium/vanadium_t7.html}.
\item[\npageref{Dutchroad}]
{\nqs{\ldots\ summer heat from roads is stored in aquifers\ldots}}
\tinyurlb{2wmuw7}{http://news.yahoo.com/s/ap/20071231/ap_on_hi_te/solar_roads;_ylt=AuEFouXxz16nP8MRlInTJMms0NUE}.
\end{widenotelist}
\nocite{ShawWatsonShort}
\nocite{ShawWatsonRance}
\nocite{ShawWatsonTrading}
\nocite{DTIAtlas}
\nocite{BakerSwansea}
\nocite{Hammons}
\nocite{Kowalik04}
\nocite{Salter2}
\nocite{BickleyRyrie}
\nocite{DTISevern}
\nocite{DinorwigDiscussion}
\nocite{Dinorwig8739}
\normalsize
% see also hydrogen.tex
\yset\chapter{\ycol{Five energy plans for Britain}}
\label{chaplan}
\label{ch.plan}
% \section{Plans that add up}
If we are to get off our current \ind{fossil fuel} \ind{addiction}
we need a \ind{plan} for radical \ind{action}. And the plan needs to
add up. The plan also needs a political and financial
\ind{roadmap}. Politics\index{politics} and \ind{economics}
are not part of this book's
brief, so here I will simply discuss what the technical
side of a plan that adds up might look like.
{%For the benefit of fig 27.1
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}%
There are many plans that add up.
In this chapter I will describe five.
Please don't take any of the plans I present as
``the author's recommended solution.''
My sole recommendation is this:
\begin{quote}
{\em Make sure your policies include a plan that adds up! }
\end{quote}
% \section{Overview}
Each plan has a consumption side and a production side:
we have to specify how much power our country will
be consuming, and how that power is to be produced.
To avoid the plans' taking many pages,
I deal with a \ind{cartoon} of our country, in which
we consume power in just three forms:
\ind{transport}, \ind{heating}, and \ind{electricity}.
This is a drastic simplification, omitting industry, farming, food,
imports, and so forth.
But I hope it's a helpful simplification, allowing us to compare and contrast
alternative plans in one minute.
Eventually we'll need more detailed plans, but today, we are
so far from our destination that I think a simple cartoon
is the best way to capture the issues.
I'll present a few plans that I believe are technically feasible for the UK
by \ind{2050}. All will share the same consumption side.
I emphasize again, this doesn't mean that I think
this is the correct plan for consumption, or the only plan.
I just want to avoid overwhelming you with
a proliferation of plans. On the production side, I will
describe a range of plans using different mixes of renewables,
\index{clean coal}\index{coal!clean}``clean coal,''
and nuclear power.
\begin{figure}
\figuremargin{
\begin{center}
\begin{tabular}{c}
\mbox{\epsfbox{metapost/stacks.803}}\\
\end{tabular}
\end{center}
}{
\caption[a]{Current consumption per person
in ``\ind{cartoon Britain} 2008'' (left two columns),
and a future consumption plan, along with a possible breakdown
of fuels (right two columns).
% This plan involves a decrease in energy consumption.
This plan requires that electricity\index{electricity!supply}
supply be increased from 18 to 48\,kWh/d per person of electricity.
}\label{CartoonBritain}
}
\end{figure}
\section{The current situation}
The current situation in our cartoon country is as follows.
Transport (of both humans and stuff)
uses 40\,kWh/d per person. Most of that energy is currently
consumed as petrol, diesel, or kerosene.
Heating of air and water
uses 40\,kWh/d per person. Much of that energy is currently provided
by natural gas.
Delivered electricity amounts to
18\,kWh/d/p and uses fuel (mainly coal, gas, and nuclear)
with an energy content of 45\,kWh/d/p.
The remaining 27\,kWh/d/p goes up cooling towers (25\,kWh/d/p)
and is lost in the wires
% and transformers
of the distribution network (2\,kWh/d/p).
The total energy input to this present-day
cartoon country is 125\,kWh/d per person.
\section{Common features of all five plans}
In my future cartoon country, the energy consumption
is reduced by using more efficient technology for
transport and heating.
% The consumption side of the plans, and some of the production side}
In the five plans for the future,
{\bf{transport}} is largely electrified.\index{electrification!of transport}
Electric engines are more efficient than petrol engines,
so the energy required for transport is reduced. Public
transport (also\index{public transport}
largely electrified) is better integrated, better personalized,
and better patronized.
%% justification:
%% ``Under a business-as-usual scenario, road transport in the UK is projected
%% to rise by 28 per cent between 2003 and 2025.'' King, quoting Eddington.
%% So maybe increase by 62% between 2007 and 2050. !!! That would mean 65 using today's tech.
%% Assume of this 65, 2 is handled by liquid fuels. The remaining 63 is reduced in the ratio 20/80 giving 16 kWh/d/p. OK - so saying 20 has given me a safety margin of 20%.
%% Note: passenger cars and other road transport are in the ratio 13:9.
%% So when King says that elec cars today would require 16% of current elec demand,
%% (cars and taxis only)
%% I can perhaps scale that up to 26% allowing for growth; then double or triple
%% to allow for the freight, which won't shrink as much as cars when electrified. So maybe 78% of current 18kWh/d -- that's 14 kWh/d/p
%% Let's nudge it down to 18, so it is the same as current elec.
I've assumed that electrification makes transport about four times
more efficient, and that economic growth cancels out some of these
savings, so that the net effect is a halving of energy consumption for
transport.
There are a few essential vehicles that can't be
easily electrified, and for those we
make our own liquid fuels (for example \ind{biodiesel} or \ind{biomethanol}
or \ind{cellulosic bioethanol}\index{bioethanol}).
The energy for transport is 18\,kWh/d/p of electricity
and 2\,kWh/d/p of liquid fuels.
% The biomass might also be converted to liquid fuels
% for use in aeroplanes.
% BTL uses the whole plant. (p4 of lufthansa doc)
% http://konzern.lufthansa.com/en/downloads/verantwortung/lh_viersaeulen.pdf
The electric vehicles' batteries serve as an\index{battery}
energy storage facility, helping to cope with \ind{fluctuations}
of electricity supply and demand.
The area required for the \index{biofuel!production}{biofuel production} is
% 80W / 0.5 = 160m**2 if it were perfectly efficient
about 12\% of the UK (500\,m$^2$ per person),
assuming that biofuel production comes from 1\%-efficient plants
and that conversion of plant to fuel is 33\% efficient.
Alternatively, the biofuels could be imported if we could persuade
other countries to devote the required (Wales-sized)
area of agricultural land to biofuels for us.
}
In all five plans,
the energy consumption of {\bf{heating}} is reduced\index{electrification!of heating} by improving
the \ind{insulation} of all buildings, and improving the control of
temperature (through thermostats, education, and the promotion of
\index{sweater wearing}sweater-wearing by \ind{sexy personalities}).
New buildings (all those built from 2010
onwards) are really well insulated and require almost no space heating.
Old buildings (which will still dominate in 2050) are mainly heated
by \index{air-source heat pump}air-source \ind{heat pump}s and \ind{ground-source heat pump}s.
Some water heating is delivered by \index{solar hot water}solar panels (2.5 square metres on every house),
% i.e. 1m*m per person
% The delivered heat is reduced from
% 40\,kWh/d/p to 30\,kWh/d/p by these measures
% the introduction of in all buildings. Heat pumps are used to heat air
some by heat pumps, and some by electricity.
Some buildings located near to managed \ind{forest}s and energy-crop plantations
are heated by biomass.
% wood, willow, or {\em{miscanthus}}.
The power required for heating is thus reduced from
40\,kWh/d/p to 12\,kWh/d/p of electricity, 1\,kWh/d/p of solar hot water,
and 5\,kWh/d/p of wood.
% breakdown: hot air 30, hot water 10
% imagine delivered heat for hot water remains 10
% (of which 1 = solar, 4=heat pump (2 elec + 2 free), and 5 plain elec)
% and hot air (was 30) reduced to 20, of which 5 wood, 15 heat pump delivered,
% which requires say 5 elec and 10 pumped heat.
% total elec required is: 5+2+5 = 12 ; heat pump (free): 10+2 = 12 ;
% 1 solar, 5 wood
% Heating total delivered is 30.
%%%% Wed 7/5/08 I have 12 elec 12 pumped 5 wood 1 solarHW
%%%%
The wood for making heat (or possibly combined heat and power) comes
from nearby forests and energy crops (perhaps \ind{miscanthus} grass,
\ind{willow}, or \ind{poplar}) covering a land area of
% 6\,million hectares, was 1000m**2 per person
30\,000\,km$^2$, or
500\,m$^2$ per person; this corresponds to 18\% of the
UK's agricultural land, which has an area of 2800\,m$^2$ per
person. The energy crops are grown mainly on the lower-grade
land, leaving the higher-grade land for food-farming.
Each 500\,m$^2$ of
energy crops yields 0.5 oven dry {\ton}s per year, which has an
% 5kWh/kg 2500kWh/y
energy content of about
7\,kWh/d; of this power, about 30\% is lost in
the process of heat production and delivery.
% Each 1000\,m$^2$ of
% energy crops yields 1\,oven dry \ton\ per year, which has an
% energy content of about 10\,GJ per year,
% or 7.6\,kWh/d; of this power, about 33\% is lost in
% the process of heat production and delivery.
% process or required for production and transport.
% 25% lost in final heat production
% 5.1 kWh/d
The final heat delivered is 5\,kWh/d per person.
In these plans, I assume the current demand for {\bf{electricity}} for
gadgets, light, and so forth is maintained. So we still require
18\,\kWhe/d/p of electricity. Yes, lighting efficiency is
improved by a switch to \index{LED}light-emitting diodes
for most lighting, and many other gadgets will get more efficient; but
thanks to the blessings of economic growth,
we'll have increased the number of gadgets in our lives -- for example
video-conferencing systems to help us travel less.
The total consumption of electricity under this plan goes {\em{up}\/}
(because of the 18\,kWh/d/p for electric transport and the
12\,kWh/d/p for heat pumps) to 48\,kWh/d/p (or 120\,GW nationally). This
is nearly a tripling of UK electricity consumption. Where's that
energy to come from?
Let's describe some alternatives. Not all of these alternatives
are ``sustainable'' as defined in this book; but they are all
low-carbon plans.
{% TROUBLESOME PAGE AREA (fig 27.3)
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
\section{Producing lots of electricity -- the components}
To make lots of electricity, each plan uses some amount
of onshore and offshore wind; some solar photovoltaics;
% figs/waste.gnu
\label{ch.waste}\marginfig{
\begin{center}
\begin{tabular}{c}
\mbox{\epsfxsize=54mm%
\mono%
{\epsfbox{figs/mono/waste.eps}}%
{\epsfbox{figs/waste.eps}}%
}
\\
\end{tabular}
\end{center}
% }{
\caption[a]{Waste-to-energy facilities in Britain.
% \index{waste to energy}
The line shows the\index{waste incineration}
average power production assuming
% a summary exchange rate:
% 100\,000\,\tons\ of waste per year $\rightarrow$
% 9\,MW; or to put it into individual terms,
1\,kg of waste $\rightarrow$ 0.5\,kWh of electricity.
% SELCHP thermal energy MSW 2.5 kWh/kg
% (Check this against the actual stats from SELCHP.) DONE
% from tim, Baldovie Scotland
% http://www.geo.ed.ac.uk/scotgaz/features/featurefirst8717.html
% Electrical export energy per waste at gate 0.61 kWh/kg
% waste at gate: 120000t/y exports 8.3MW (net) own use: 2.2MW
}
\label{fig.waste}
%# 9000*24 / (100000e3/365.25 )
%#ans = 0.78894
%#octave:10> 9000 * 365.25 * 24 / 100000e3
}%
possibly some solar power bought from countries with deserts;
waste incineration (including refuse and agricultural waste);
hydroelectricity (the same amount as we get today);
perhaps wave power; \ind{tidal barrage}s,
\ind{tidal lagoon}s, and \ind{tidal stream} power; perhaps \ind{nuclear power}; and perhaps
some ``clean fossil fuel,'' that is, coal
burnt in power stations that do carbon capture and storage.
Each plan aims for a total electricity production of 50\,kWh/d/p
on average -- I got this figure by rounding up
% , giving a small safety margin over
the 48\,kWh/d/p of average demand, allowing for some loss
in the distribution network.
% I won't include any natural gas, because
% `clean gas' does not seem so sustainable an option for the UK as `clean coal'.
% Alternative plans that include clean gas (not that I know where you'd be
% buying it from in 2050) can be created by
Some of the plans that follow will import power from
other countries. For comparison, it may be helpful to know
how much of our current power is imported today.
The answer is that, in 2006, the UK imported 28\,kWh/d/p of fuel
% (or, in conventional units, 70\,GW, or 52\,Mtoe),
-- 23\% of
its primary consumption.
These \index{imported power}imports
are dominated by \ind{coal} (18\,kWh/d/p), \ind{crude oil}\index{oil} (5\,kWh/d/p),
and \ind{natural gas}\index{gas} (6\,kWh/d/p).
% from DUKES
% [34.2 9 10.6 0.6 52.4] * 1.326 / 2.5
%ans =
%
% 18.13968 4.77360 5.62224 0.31824 27.79296
Nuclear fuel (\ind{uranium}) is not usually counted as an import since it's
easily stored.
In all five plans I will assume that we scale up
municipal waste incineration so that almost all waste that can't usefully be
recycled\index{recycling} is incinerated
rather than landfilled.\index{landfill}
Incinerating%
%\marginfig{
\begin{figure}
\figuremargin{
\noindent\begin{tabular}{ll}
\hspace*{-1mm}\mbox{\epsfxsize=75mm%
{\epsfbox{../data/landfillVincin.eps}}% landinc.gnu
}%
&
\raisebox{0.53971mm}{\epsfxsize=98.15mm%
{\epsfbox{../data/recycle3.eps}}% recycle.gnu
}%
\\
\end{tabular}
}{
% COLON
\caption[a]{Left: Municipal solid waste put into \ind{landfill}, versus
amount incinerated, in\index{Europe}\index{municipal solid waste}\index{waste incineration}\index{data!landfill}\index{data!waste}\index{data!incineration}\index{data!recycling}\index{recycling!data}
kg per day per person, by country.
Right: Amount of waste recycled versus amount landfilled or incinerated.
Percentage of waste recycled is given beside each country's name.
% Data from Eurostat, \myurl{www.epa.gov}, and \myurl{www.esrcsocietytoday.ac.uk/ESRCInfoCentre/}.
}\label{figMuniLandIncRec}
}
\end{figure}
1\,kg per day per person of waste
% If we assume one third of this is recycled then the remainder
yields roughly 0.5\,kWh/d per person of electricity.\nlabel{WasteCal}
% (\figref{fig.waste}).
I'll assume that a similar amount of \ind{agricultural waste}
is also incinerated, yielding 0.6\,kWh/d/p.
Incinerating this waste requires roughly 3\,GW of waste-to-energy
capacity, a ten-fold increase over the incinerating
power stations of 2008 (\figref{fig.waste}).
%# there are 46 cities in Britain
% see data/towns for 190 places
\ind{London} (7 million people) would have twelve 30-MW waste-to-energy plants like
the SELCHP plant in South London (see \pref{pSELCHPapp}).
\ind{Birmingham} (1 million people) would have two of them.
% like Allington Quarry.
Every town of 200\,000 people would have a 10\,MW waste-to-energy plant.
Any fears that waste incineration at this scale
would be difficult, dirty, or dangerous should be
allayed by \figref{figMuniLandIncRec}, which shows that many countries
in Europe incinerate {\em{far}\/} more waste per person
than the UK; these incineration-loving countries include
Germany, Sweden, Denmark, the Netherlands, and Switzerland --
% all nations famous for their high environmental standards.
not usually nations associated with hygiene problems!
% Every town of 100\,000 people would have a 5\,MW waste-to-energy plant.
One good side-effect of this waste incineration plan is that it eliminates
future \ind{methane} emissions from landfill sites.
In all five plans,
\ind{hydroelectricity} contributes
0.2\,kWh/d/p, the same as today.
% amount as we get from hydro today.
Electric vehicles are used as a dynamically-adjustable load
on the electricity network.
The average power required to charge the \ind{electric vehicle}s is
45\,GW (18\,kWh/d/p).
% 50\,GW (20\,kWh/d/p).
So fluctuations in renewables such as solar and wind
can be balanced by turning up and down
this load, as long as the fluctuations are not too big
or lengthy.
%
Daily swings in electricity demand are going to be bigger than they
are today
because of the replacement of gas for \ind{cooking} and heating
by electricity (see \figref{fig.gasdemand2}, \pref{fig.gasdemand2}).\nlabel{gasdemand}
To ensure that surges in demand of 10\,GW lasting
up to 5 hours can be
covered, all the plans would build five new pumped storage
facilities like Dinorwig (or upgrade hydroelectric facilities
to provide pumped storage).
50\,GWh of storage
is equal to five Dinorwigs, each with a capacity of 2\,GW\@.
Some of the plans that follow
% have lots of wind power
will require extra pumped storage beyond this.
For additional insurance, all the plans would build
an electricity interconnector to Norway,\index{interconnector!Norway} with a capacity of 2\,GW\@.
}
% End of TROUBLESOME PAGE AREA (fig 27.3)
\section{Producing lots of electricity -- plan D}
Plan D (``D'' stands for ``domestic \ind{diversity}'')
uses a\index{plan D}
lot of every possible domestic source
of electricity, and depends relatively little on energy supply
from other countries.
Here's where plan D gets its 50\,kWh/d/p of electricity from.
Wind: 8\,kWh/d/p (20\,GW average; 66\,GW peak) (plus about 400\,GWh of
associated pumped storage facilities).
Solar PV: 3\,kWh/d/p.
Waste incineration: 1.3\,kWh/d/p.
Hydroelectricity: 0.2\,kWh/d/p.
Wave: 2\,kWh/d/p.
Tide: 3.7\,kWh/d/p.
Nuclear: 16\,kWh/d/p (40\,GW).
``Clean coal'': 16\,kWh/d/p (40\,GW).
% Total: 50\,kWh/d/p.
To get 8\,kWh/d/p of wind requires a 30-fold increase in wind power
\marginfig{
\begin{center}
\begin{tabular}{c}
{\mbox{\epsfbox{metapost/stacks.815}}}\\% use 805 to get planD label built in
\end{tabular}
\end{center}
% }{
\caption[a]{Plan D}
\label{planD}
}%
over the installed power in 2008. Britain would have nearly 3 times
as much wind hardware as Germany has now.
%% see offshore
Installing this much windpower offshore over a period of 10 years
would require roughly 50 jack-up barges.\index{offshore wind!jack-up barges}\index{wind!offshore!jack-up barges}\index{jack-up barge}
% tried this to solve OHB problem
Getting
% To get
3\,kWh/d/p from solar photovoltaics requires 6\,m$^2$
of 20\%-efficient panels per person. Most south-facing
roofs would have to be completely covered with panels; alternatively,
it might be more economical, and cause less distress
to the League for the Preservation of Old Buildings,
to plant many of these panels in the
countryside in the traditional Bavarian manner (\figref{fig.bavaria},
\pref{fig.bavaria}).\index{solar!farm}\index{farm!solar}
The waste incineration corresponds to
1\,kg per day per person of domestic waste
(yielding 0.5\,kWh/d/p) and a similar amount of agricultural waste
yielding 0.6\,kWh/d/p;
the hydroelectricity is 0.2\,kWh/d/p, the same amount
as we get from hydro today.
% PEAK power from 7500 at 0.750MW each is 5.6GW which is 2.2kWh/d/p
% that is 19 Pelamis per km. 308kW each avg. 750kW each capacity.
% 6MW per km average 14.25 MW per km peak
% Here we need 5000MW
The wave power requires 16\,000 \ind{Pelamis} deep-sea wave devices
occupying 830\,km of Atlantic coastline (see the map on \pref{pAt}).
The tide power comes from 5\,GW of tidal stream installations,
a 2\,GW Severn barrage, and 2.5\,GW of tidal lagoons, which can
serve as pumped storage systems too.
To get 16\,kWh/d/p of nuclear power
requires 40\,GW of nukes, which
is a roughly four-fold increase of the 2007 nuclear fleet.
If we produced 16\,kWh/d/p of nuclear power,
we'd lie between \ind{Belgium}, \ind{Finland}, \ind{France} and \ind{Sweden},
in terms of per-capita production: Belgium and Finland each produce
roughly 12\,kWh/d/p; France and Sweden produce 19\,kWh/d/p
and 20\,kWh/d/p respectively.
To get 16\,kWh/d/p of ``clean coal'' (40\,GW), we would have
to take the current fleet of
coal stations, which deliver about 30\,GW, retrofit carbon-capture
systems to them, which would reduce their output to 22\,GW, then
build another 18\,GW of new clean-coal stations.
This level of coal power requires an energy input of about 53\,kWh/d/p of coal,
which is a little bigger than the total rate at which we currently burn {\em{all}\/}
fossil fuels at power stations,
and well above the level we
estimated as being ``sustainable'' in \chref{ch.sff}.
This rate of consumption of coal is roughly three times
the current rate of coal imports (18\,kWh/d/p).
If we didn't reopen UK \ind{coal mines},
this plan would have 32\% of UK electricity depending on
imported coal.
%% possible uk coal production is 23Mt per year in the DTI-PIU doc.
%% at 26.7 GJ/tonne that is
%% 7.8 kWh/d/p
Reopened UK coal mines could deliver an energy input of about
8\,kWh/d/p,
% from DTI-PIU.pdf -- 23Mt/y.
so either way, the UK would not be self-sufficient for coal.
Do any features of this plan strike you as unreasonable
or objectionable?
If so, perhaps one of the next four plans is more to your liking.
% In all the plans that follow, the electricity contributions of
% hydroelectricity and waste incineration
% : 1.3\,kWh/d/p.
% are going to remain unchanged, so I won't mention them again.
\section{Producing lots of electricity -- plan N}
Plan N is the ``\ind{NIMBY}'' plan, for people who don't like
industrializing the British \ind{countryside} with renewable energy\index{plan N}
facilities, and who don't want new nuclear power stations either.
Let's reveal the plan in stages.
\amarginfig{b}{
\begin{center}
\begin{tabular}{c}
{\mbox{\epsfbox{metapost/stacks.816}}}\\ % N
%&{\mbox{\epsfbox{metapost/stacks.807}}}\\% extra L
\end{tabular}
\end{center}
% }{
\caption[a]{Plan N}
\label{planN}
}First, we turn down all the renewable knobs from their
very high settings in plan D to:
wind: 2\,kWh/d/p (5\,GW average);
solar PV: 0;
% \,kWh/d/p;
wave: 0;
% \,kWh/d/p;
tide: 1\,kWh/d/p.
We've just lost ourselves 14\,kWh/d/p (35\,GW nationally) by turning down
the renewables. (Don't misunderstand!
Wind is still eight-fold increased over its 2008 levels.)
In the NIMBY plan,
we reduce the contribution of nuclear power to 10\,kWh/d/p (25\,GW)
% Nuclear 10\,kWh/d/p (25\,GW).
% Clean coal: 16\,kWh/d/p (40\,GW).
-- a reduction by 15\,GW compared to plan D, but still a
substantial increase over today's levels. 25\,GW of nuclear
power could, I think, be squeezed onto the existing nuclear sites,
so as to avoid imposing on any new back yards.
I left the clean-coal contribution unchanged at 16\,kWh/d/p (40\,GW).
The electricity contributions of hydroelectricity and waste incineration
remain the same as in plan D\@.
Where are we going to get an extra 50\,GW from?
% We could perhaps make a plan with more clean fossil fuels, but it seems more consistent with t
The NIMBY
says, ``not in my back yard, but in someone else's.''
Thus the NIMBY plan pays other countries for
imports of solar power from their deserts to the
tune of 20\,kWh/d/p
% per day per person
(50\,GW).
% Solar power in deserts: 20\,kWh/d/p (50\,GW).
% Total: 50\,kWh/d/p.
% I confirm this diam is consistent with the 1500km**2 concept. Each blob generates 10GW avg.
% five blobs are 50GW
This plan requires the creation of
five blobs each the size of London (44\,km in
diameter) in the transmediterranean desert, filled with solar power stations.
It also requires power \ind{transmission} systems to get 50\,GW of power
up to the UK\@.
% Once we've decided to \index{imports!energy}{import} solar power from other countries, there's
% little point having solar PV on our roofs at home -- the same panels
% could always generate more in a sunnier country.
Today's high voltage electricity connection\index{England--France interconnector}
from \ind{France} can deliver
only 2\,GW of power. So this plan requires a 25-fold increase
in the capacity of the electricity connection from the continent.
(Or an equivalent power-transport solution -- perhaps ships filled with
\ind{methanol} or \ind{boron} plying their way from desert shores.)
% (neglected losses)
Having less wind power, plan N doesn't need to build in Britain
the extra pumped-storage facilities
mentioned in plan D, but given its dependence on sunshine,
it still requires storage systems to be built somewhere
% along the line
to store energy from the fluctuating sun. Molten salt storage systems
at the solar power stations are one option. Tapping into pumped storage
systems in the \ind{Alps} might also be possible. Converting the
electricity to a storable fuel such as \ind{methanol} is another option,
though conversions entail losses and thus require more solar power stations.
This plan gets $32\%+40\%=72\%$ of the UK's electricity
from other countries.\index{imports!energy}
\section{Producing lots of electricity -- plan L}
Some people say ``we don't want nuclear power!''\index{plan L}
How can we satisfy them? Perhaps it should be the job of this
anti-nuclear bunch to persuade the NIMBY bunch that they do want
renewable energy in our back yard after all.
\amarginfig{b}{
\begin{center}
\begin{tabular}{c}
{\mbox{\epsfbox{metapost/stacks.817}}}\\
\end{tabular}
\end{center}
% }{
\caption[a]{Plan L}
\label{planL}
}We can create a nuclear-free plan by taking plan D,
keeping all those renewables in our back yard,
and doing a straight swap of
nuclear for desert power. As in plan N, the delivery of desert power requires
a large increase in transmission systems between North Africa and
Britain; the Europe--UK interconnectors would need to be increased from
2\,GW to at least 40\,GW.
Here's where plan L gets its 50\,kWh/d/p of electricity from.
Wind: 8\,kWh/d/p (20\,GW average) (plus about 400\,GWh of
associated pumped storage facilities).
Solar PV: 3\,kWh/d/p.
Hydroelectricity and waste incineration: 1.3\,kWh/d/p.
Wave: 2\,kWh/d/p.
Tide: 3.7\,kWh/d/p.
``Clean coal'': 16\,kWh/d/p (40\,GW).
Solar power in deserts: 16\,kWh/d/p (40\,GW average power).
% The electricity contributions of hydroelectricity and waste incineration
% remain the same as in plan D\@.
% Total: 50\,kWh/d/p.
This plan imports 64\% of UK electricity from other countries.
I call this ``plan L'' because it aligns fairly well with
the policies of the \ind{Liberal Democrats} -- at least
it did when I first wrote this chapter in mid-2007;\nlabel{libdempol}
recently, they've been talking about
% Liberal Democrat policy paper 82
``real energy independence for the UK,''
and have announced a zero-carbon policy,
under which Britain would be a net energy {\em exporter};
their policy does not detail how these targets would be met.
\section{Producing lots of electricity -- plan G}
\amarginfig{t}{
\begin{center}
\begin{tabular}{c@{}c}
{\mbox{\epsfbox{metapost/stacks.818}}}&\\
%& \mbox{\epsfbox{metapost/stacks.809}}\\%% E
\end{tabular}
\end{center}
% }{
\caption[a]{Plan G}
\label{planG}
% \label{planE}
}Some people say ``we don't want nuclear power, {\em and\/} we don't want coal!''
It sounds a desirable goal, but we need a plan to deliver it.
%
I call this ``\ind{plan G},'' because I guess the \ind{Green Party}
don't want nuclear or coal, though I think not all Greens would
like the rest of the plan. \ind{Greenpeace}, I know, {\em{love}\/} wind,
so plan G is dedicated to them too, because it has
{\em{lots}\/} of wind.
% 1Mtoe/y = 1.326 GW
I make plan G by starting again from plan D, nudging up the
wave contribution by 1\,kWh/d/p (by pumping money into
wave research and increasing the efficiency of the Pelamis converter)
and bumping up wind power fourfold
(relative to plan D)
% by a whopping 24\,kWh/d/p
to 32\,kWh/d/p, so that wind delivers
64\% of all the electricity.
This is a 120-fold increase of British wind power over today's levels.
% world is 74\,GW\@. This is three times that.
Under this plan, {\em{world}\/}
wind power in 2008 is multiplied by 4, with all
of the increase being placed on or around the British Isles.
The immense dependence of plan G on renewables, especially wind,
creates difficulties for our main method of balancing
supply and demand, namely adjusting the charging rate of
millions of rechargeable batteries for transport.
So in plan G we have to include substantial additional
pumped-storage
facilities, capable of balancing out the \ind{fluctuations} in
\ind{wind} on a timescale of days. Pumped-storage facilities
equal to 400 Dinorwigs can completely replace wind
for a national lull lasting 2 days.
% Most major \ind{loch}s in \ind{Scotland}
% would be part of \index{pumped storage}{pumped-storage} systems.
Roughly 100 of Britain's major lakes and lochs would
be required for the associated pumped-storage systems.\index{pumped storage}
Plan G's electricity breaks down as follows.
Wind: 32\,kWh/d/p (80\,GW average) (plus about 4000\,GWh of
associated pumped-storage facilities).
Solar photovoltaics: 3\,kWh/d/p.
Hydroelectricity and waste incineration: 1.3\,kWh/d/p.
Wave: 3\,kWh/d/p.
Tide: 3.7\,kWh/d/p.
Solar power in deserts: 7\,kWh/d/p (17\,GW).
% The electricity contributions of hydroelectricity and waste incineration
% remain the same as in plan D\@.
% Total: 50\,kWh/d/p.
This plan gets 14\% of its electricity from other countries.
\section{Producing lots of electricity -- plan E}
\marginfig{
\begin{center}
\begin{tabular}{c}
\mbox{\epsfbox{metapost/stacks.819}}\\% planE
\end{tabular}
\end{center}
% }{
\caption[a]{Plan E}
\label{planE}
}%
E stands for ``\ind{economics}.''\index{plan E}
This fifth plan is a rough guess for what might happen in a liberated
energy market with a strong \ind{carbon price}.
On a level economic playing field with a strong price signal
preventing the emission of \COO, we don't expect a diverse solution with a wide
range of power-costs; rather,
we expect an economically optimal solution that delivers the
required power at the lowest \ind{cost}.
And when ``clean coal'' and \ind{nuclear} go head to head on price,
it's nuclear that wins. (Engineers at a UK electricity
generator told me that the capital cost of regular {\em{dirty}\/}
coal power stations is \pounds 1\,billion per GW, about the same as
nuclear; but the capital cost of ``clean-coal'' power, including carbon capture
and storage, is roughly \pounds 2\,billion per GW\@.)
% For both nuclear power
% and ``clean coal'', these costs are building costs,
% and don't necessarily include the full cost of disaster-insurance.)
% source Andrew Read, E-ON. KingsNorth will have a power of 1.6GW
% and would deliver only 1.2-1.3GW if it did CCS.
% CCS becomes economic if co2 costs 60 pounds per t.
% Clean Coal CCS is cheaper than offshore wind.
I've assumed that solar power in other people's deserts loses to nuclear power
when we take into account the cost of the required
2000-km-long \ind{transmission lines} (though
\citet{CSPvanV} reckons that with Nobel-prize-worthy developments in
solar-powered production of chemical fuels, solar power in deserts
would be the economic equal of nuclear power).
Offshore wind also loses to nuclear,
but I've assumed that onshore wind costs about the same as nuclear.
Here's where plan E gets its 50\,kWh/d/p of electricity from.
Wind: 4\,kWh/d/p (10\,GW average).
% (plus about 200\,GWh of
% associated pumped storage facilities).
Solar PV: 0.
% \,kWh/d/p.
Hydroelectricity and waste incineration: 1.3\,kWh/d/p.
Wave: 0.
% \,kWh/d/p.
Tide: 0.7\,kWh/d/p. And nuclear: 44\,kWh/d/p (110\,GW).
% The electricity contributions of hydroelectricity and waste incineration
% remain the same as in plan D\@.
% Total: 50\,kWh/d/p.
This plan has a ten-fold increase in our nuclear power over 2007 levels.
Britain would have 110\,GW, which is roughly double \ind{France}'s nuclear fleet.
I included a little tidal power because I believe a well-designed \ind{tidal lagoon}
facility can compete with nuclear power.
In this plan, Britain has no energy imports
(except for the uranium,\index{imports!energy}
which, as we said before, is not conventionally counted as an import).
\Figref{fivepl} shows all five plans.
\begin{figure}
\figuredangle{
\begin{center}
\mbox{\epsfbox{metapost/stacks.824}}\\
\end{center}
}{
\caption[a]{All five plans.%% switch to 824 to get headings
}\label{fivepl}
}
\end{figure}
\section{How these plans relate to carbon-sucking and air travel}
In a future world where carbon pollution is priced appropriately
to prevent catastrophic climate change,
we will be
interested in\index{cofiring biomass}\index{air travel!neutralization}\index{jet travel}
any power scheme that can at low cost put extra carbon down a
hole in the ground.\index{carbon sequestration!by cofiring biomass}
Such carbon-neutralization\index{carbon neutralization}
schemes might permit us to continue {flying}\index{flight!future of}
at 2004 levels (while oil lasts). In 2004, average UK emissions
of \COO\ from flying were about 0.5\,t\,\COO\ per year per person.
% \marginpar{\small 1\,t = one ton}
Accounting for the full greenhouse impact of flying,
perhaps the effective emissions were about\marginfignocaption{\small 1\,t\,\COOe\ means greenhouse-gas emissions equivalent to one ton of \COO.}
1\,t\,\COOe\ per year per person.
Now, in all five of these plans I assumed that one eighth of the UK was
devoted to the production of energy crops which were then
used for heating or for combined heat and power.
If instead we directed all these crops to
power stations with carbon capture and storage --
the ``clean-coal'' plants that featured in three of the plans --
then the amount of extra \COO\ captured would be about 1\,t of \COO\
per year per person.
% Perhaps 1.5t\COO.
If the municipal and agricultural waste incinerators were located
at clean-coal plants too so that they could share the same chimney,
perhaps the total captured could be increased to
2\,t\,\COO\ per year per person.
% wood CH2O 12/(12+2+16) * 44/12 = 1.4667
This arrangement would have additional costs: the biomass and waste
might have to be transported further; the carbon-capture process\index{carbon capture}
would require a significant fraction of the energy from the crops;\index{carbon sequestration!cofiring}\index{biomass!cofiring}
and the lost building-heating would have to be replaced by
more \ind{air-source heat pump}s.
But, if carbon-neutrality is our aim,
it would be worth planning ahead by
seeking to locate new clean-coal plants with\index{clean coal}\index{coal!clean}
waste incinerators\index{waste incineration}
in regions close to potential \index{biomass!plantation}{biomass plantation}s.
\section{``All these plans are absurd!''}
If you don't like these plans, I'm not surprised.
I agree that there is something unpalatable about every one of them.
Feel free to make another plan that is more to your liking.
But make sure it adds up!
Perhaps you will conclude that a viable plan has to involve
less power consumption per capita. I might agree with that,
but it's a difficult policy to sell -- recall \index{Blair, Tony}Tony
Blair's response (\pref{abia})
when someone suggested he should fly overseas for holidays less frequently!
Alternatively, you may conclude that we have too high a \ind{population density},
and that a viable plan requires fewer people.
% You wouldn't be the first to suggest the need for population reduction.
Again, a difficult policy to sell.
% \section{What about growth?}
% Don't forget that growth
% I need to talk about growth and \figref{fig.En1}.
% \newpageone
%% opposition links
%% http://www.countryguardian.net/Campaign%20Windfarm%20Action%20Groups.htm
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{WasteCal}]
{\nqs{Incinerating 1\,kg of waste
% If we assume one third of this is recycled then the remainder
yields roughly 0.5\,kWh of electricity.}}
The \ind{calorific value} of municipal solid waste is about
2.6\,kWh per kg; power stations burning waste
produce\index{waste incineration!efficiency}
% \index{waste to energy!efficiency}
electricity with an efficiency of about 20\%. Source: SELCHP tour guide.
\item[\npageref{figMuniLandIncRec}]
{\nqs{\Figref{figMuniLandIncRec}.}}
Data from Eurostat, \myurl{www.epa.gov}, and \myurl{www.esrcsocietytoday.ac.uk/ESRCInfoCentre/}.
\item[\npageref{libdempol}]
{\nqs{The policies of the \ind{Liberal Democrats}}}.
See \myurl{www.libdems.org.uk}:
% http://www.libdems.org.uk/news/http-www-libdems-org-uk-news-clegg-calls-for-apollo-project-to-secure-uks-energy-independence.14971.html
\tinyurl{5os7dy}{http://tinyurl.com/5os7dy},
\tinyurl{yrw2oo}{http://tinyurl.com/yrw2oo}.
% {http://www.libdems.org.uk/media/documents/Energy%20Independence%20for%20the%20UK.pdf}.
% http://www.libdems.org.uk/media/documents/policies/zero%20carbon.pdf
% is \tinyurl yrw2oo
\end{notelist}
\normalsize
\yset\chapter{\ycol{Putting costs in perspective}}
\label{ch.costs}
\section{A plan on a map}
Let%
\amarginfig{t}{
\begin{center}
\begin{tabular}{c}
{\mbox{\epsfbox{metapost/stacks.820}}}\\
\end{tabular}
\end{center}
% }{
\caption[a]{Plan M\index{plan M}}
\label{planM}
}
me try to make clear the scale
of the previous chapter's plans by showing you a map of Britain bearing a sixth plan.
This sixth plan lies roughly in the middle of the first five,
so I call it plan M (\figref{planM}).
\begin{figure}
\figuremargin{%\hspace*{55mm}%
\mbox{%
\epsfig{file=../../images/PUBLICDOMAIN/maps/uk.eps}% see also scot.eps eng.eps
%{\raisebox{3in}{\epsfbox{metapost/stacks.820}}}%
% see uk.sh uk
\makebox[0pt][r]{%
\raisebox{100mm}{\makebox[10pt][l]{\epsfig{width=85pt,height=134pt,file=../../images/PUBLICDOMAIN/maps/white.eps}}%
\raisebox{5pt}{\epsfig{file=../../images/PUBLICDOMAIN/maps/key.eps}}\hspace*{-1mm}}%}%
}}\\
}{
\caption[a]{A \ind{plan} that adds up, for Scotland, England, and Wales.
The grey-green squares are
{\windfarm}s. Each is 100\,km$^2$ in size and is shown to scale.
\par
The red lines in the sea are {\wavefarm}s, shown to scale.
\par
Light-blue lightning-shaped polygons: solar photovoltaic farms --
20\,km$^2$ each, shown to scale.
\par
Blue sharp-cornered polygons in the sea: {\tidefarm}s.
% Not all of the areas shown would be required.
\par
Blue blobs in the sea (Blackpool and the Wash): tidal lagoons.
\par
Light-green land areas: woods and short-rotation coppices (to scale).
\par
Yellow-green areas: biofuel (to scale).
\par
Small blue triangles: waste incineration plants (not to scale).
\par
Big brown diamonds: clean coal power stations, with cofiring of biomass, and
carbon capture and storage (not to scale).
\par
Purple dots: nuclear power stations (not to scale) -- 3.3\,GW average production
at each of 12 sites.
\par
Yellow hexagons across the channel: concentrating solar power facilities in remote deserts
(to scale, 335\,km$^2$ each).
The pink wiggly line in France represents
new HVDC lines, 2000\,km long, conveying 40\,GW from remote deserts
to the UK.
% (Land area required in continental Europe: 1200\,km$^2$.)
\par
Yellow stars in Scotland: new pumped storage facilities.
\par
Red stars: existing pumped storage facilities.
\par
Blue dots: solar panels for hot water on all roofs.
}
\label{fig.eng}
}
\end{figure}%
% More explanatory notes to come here. TBC.
% Let's look at this plan in a bit more detail to assess
% its costs: its land area costs, and its financial costs.
The areas and rough costs of these facilities are shown in
\tabref{tab.planM}.
%
For simplicity, the financial costs are estimated using today's prices
for comparable facilities, many of which are early prototypes.
We can expect many of the prices to drop significantly.
The rough costs given here are the building costs, and don't include
running costs or decommissioning costs.
The ``per person'' costs are found by dividing the
total cost by 60 million. Please remember, this
is not a book about economics -- that would require another 400 pages!
I'm providing these cost estimates
only to give a {\em{rough}\/} indication of the price tag we should
expect to see on a plan that adds up.
% 8.5M pounds for the seagen prototype
% A new 1250\,\MWe nuclear power plant located at one of the
% existing nuclear power sites in Finland would cost 2200 million euros
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{table}
\fullwidthfigureright{\small % 0.7954in}
\noindent
\begin{tabular}{p{2in}p{1.231in}p{24mm}p{27mm}p{0.75in}} \toprule
& Capacity & Rough cost & & Average power \\
& & \mbox{}\moneycol{total} & per person & delivered \\
\midrule
52 onshore {\windfarm}s:
% , 100\,km$^2$ each
\areacol{5200\,km$^2$}
&
% Capacity:
% 0.67\,GW per windfarm. Total capacity
35\,GW
&
\mbox{}\moneycol{\pounds27\bn} & \pounds450
% \par
% the projected cost of
% , \pounds 500\,million for 650\,MW.)
&
% Average power delivered:
\mbox{\OliveGreen{4.2\,kWh/d/p}}
% 4.16\,kWh/d/p.
% \\[18pt]%two_lines
\\
& & \multicolumn{2}{p{55mm}}{
\mbox{}\raisebox{3pt}{\Gray{\footnotesize -- based on Lewis {\windfarm}}}}
\\[7pt]%oneline
% Based on the projected cost of Lewis {\windfarm}, \pounds 500\,million for 650\,MW.)} \\
29 offshore {\windfarm}s:
% , 100\,km$^2$ each
\areacol{2900\,km$^2$}
&
% Capacity:
% 1\,GW per {\windfarm}. Total capacity
29\,GW
&
\mbox{}\moneycol{\pounds36\bn} & \pounds650
% the cost of
% -- based on \ind{Kentish Flats}, \& including \pounds3bn capital investment in\index{offshore wind!jack-up barges}\index{wind!offshore!jack-up barges}\index{jack-up barge} jack-up barges.)
&
% Average power delivered:
\mbox{\OliveGreen{3.5\,kWh/d/p}}
% 3.48
% \\[28pt]%three_lines
\\[-2pt] & & \multicolumn{2}{p{55mm}}{
\mbox{}\Gray{\footnotesize -- based on \ind{Kentish Flats}, \& including \pounds3bn
investment in\index{offshore wind!jack-up barges}\index{wind!offshore!jack-up barges}\index{jack-up barge} jack-up barges. }}
\\[18pt]%two_lines
Pumped storage:\par
\ \ \ 15 facilities similar to \ind{Dinorwig}
&
30\,GW
&
\mbox{}\moneycol{\pounds15\bn}
& \pounds 250
&
% Glendoe cost 140M pounds and had capacity of 100MW
% - for build from scratch
\\[18pt]%two_lines
% & & \multicolumn{2}{p{55mm}}{(Based on the cost of Kentish Flats, including \pounds3bn capital investment in\index{offshore wind!jack-up barges}\index{wind!offshore!jack-up barges}\index{jack-up barge} jack-up barges.) } \\[0.05in]
Photovoltaic farms: \areacol{1000\,km$^2$}
&
% Capacity:
48\,GW
&
% Rough cost:
% 6.3MW for 31 M euro -> 236b euro
% 236 billion Euros = 189.912859 billion British pounds
\mbox{}\moneycol{\pounds 190\bn} & \pounds3200
% \par -- based on \ind{Solarpark} in \ind{Bavaria}
% \ind{M\"uhlhausen},
&
\mbox{\OliveGreen{2\,kWh/d/p}}
\\[-2pt]& & \multicolumn{2}{p{55mm}}{
\mbox{}\Gray{\footnotesize -- based on \ind{Solarpark} in \ind{Bavaria} }}
\\[7pt]
% \\[18pt]%two_lines
% & & \multicolumn{2}{p{55mm}}{(Based on \ind{Solarpark} in
% \ind{M\"uhlhausen}, \ind{Bavaria})} \\[0.05in]
Solar hot water panels:
\par
\ \ \ 1\,m$^2$ of roof-mounted panel
\par
\ \ \ per person.
(\areacol{60\,km$^2$} total)
&
%% £3332.38 ex VAT for 2.8 sq m
%% http://www.solartwin.com/installation.php
2.5\,\GWth\par average
&
\mbox{}\moneycol{\pounds72\bn} & \pounds1200
&
\mbox{\OliveGreen{1\,kWh/d/p}}
\\[29pt]%three_lines
Waste incinerators:
% \par
% \ \ \ 100 new 30\,MW incinerators
&
3\,GW
&
\mbox{}\moneycol{\pounds8.5\bn} &
\pounds 140
% -- based on \ind{SELCHP}, which cost \pounds85 million
&
% 142
\mbox{\OliveGreen{1.1\,kWh/d/p}}
% requires 2.75GW average!
\\
\ \ \ 100 new 30\,MW incinerators
& & \multicolumn{2}{p{55mm}}{
\mbox{}\Gray{\footnotesize -- based on \ind{SELCHP}}% , which cost \pounds85M
}
\\[7pt]%two_lines
Heat pumps
% 8kW capacity per person? or per household? Let's say 3.5kW per person
% of heat output. So ``pumped heat'' capacity of 2.6kW in my diagram (assuming 0.75)
% cf 0.5kW assumed average.
% assume 3.5kW costs 300 pounds? 1000 pounds? Grant is 1000 pounds so it must cost
% 3000 (for 8kW)! ie 1000 pounds for each 3.5kW
% If the project was for say 500 units or so then these prices could fall by
% as much as 40% if several manufacturers were battling it out!
% B Warm 8000 costs 3600 pounds , from John Lightfoot (50C water) (for one-off buy)
% 8kW and 40% less if bulk buy. Great, exactly 1000 pounds per person in bulk.
% for 3.5kW.
&
% 3.5kW * 60 million is
210\,\GWth
% ermal
&
\mbox{}\moneycol{\pounds60\bn}
&\pounds1000
&
\mbox{\OliveGreen{12\,kWh/d/p}}
\\[7pt]%[0.1in]
{\Wavefarm}s
--
2500 Pelamis,\par
\ \ \ \Red{130\,km} of sea
% 130 km * 19 pelamis per km is 2500, which deliver 760MW total average (0.3kWhd)
% 3 Pelamis: installed capacity of 2.25MW at a cost of £8 million.
&
1.9\,GW
\par (0.76\,GW average)
&
% 6.6bn is what it comes out to. I rounded down out of charity.
\mbox{}\moneycol{\pounds6\bn}?
& \pounds100
&
\mbox{\OliveGreen{0.3\,kWh/d/p}}
\\[18pt]%two_lines
Severn barrage:
\areacol{550\,km$^2$}
&
8\,GW
(2\,GW average)
&
\mbox{}\moneycol{\pounds15\bn}
& \pounds250
&
\mbox{\OliveGreen{0.8\,kWh/d/p}}
\\[7pt]
Tidal lagoons: \areacol{800\,km$^2$}
% If Assume 1.75Wmm -> need 1e3 km**2
% I show 800km^2 on the map which means 2.2Wmm
&
1.75\,GW
average
&
\mbox{}\moneycol{\pounds2.6\bn}?
&\pounds45
&
\mbox{\OliveGreen{0.7\,kWh/d/p}}
\\[7pt]%two_lines
% assume same cost and load factor (30%) as wind
Tidal stream: \par
% 18GW peak, 30% load factor? strangford is 1.2MW
\ \ \ 15\,000 turbines -- \areacol{2000\,km$^2$}
% 1.2MW each I assumed 8Wmm
&
18\,GW\par (5.5\,GW average)
&
\mbox{}\moneycol{\pounds21\bn}?
& \pounds350
&
\mbox{\OliveGreen{2.2\,kWh/d/p}}
\\[18pt]%two_lines
Nuclear power:
40 stations
&
45\,GW
% average output 40GW
&
\mbox{}\moneycol{\pounds60\bn}
% 2.2bn euro each (1.25GW) ie 1.5bn pounds
& \pounds1000
% \par -- based on \ind{Olkiluoto}, \ind{Finland}
&
\mbox{\OliveGreen{16\,kWh/d/p}}
\\[-2pt]& & \multicolumn{2}{p{55mm}}{
\mbox{}\Gray{\footnotesize -- based on \ind{Olkiluoto}, \ind{Finland}}
}
\\[7pt]%two_lines
Clean coal
&
8\,GW
% average output 7.5GW
&
\mbox{}\moneycol{\pounds16\bn}
% 2bn pounds per GW from EoN
& \pounds270
&
\mbox{\OliveGreen{3\,kWh/d/p}}
\\[7pt]%[0.1in]
Concentrating solar power
% \par
% \ \ \ in deserts:
% \areacol{2700\,km$^2$}
&
% Average output:
%\par 40\,GW
40\,GW average
&
\mbox{}\moneycol{\pounds340\bn}
% solucar cost 35M euro for 2.8MW average
& \pounds5700
% \par -- based on \ind{Sol\'ucar}
&
\mbox{\OliveGreen{16\,kWh/d/p}}
\\
\ \ \ in deserts: \areacol{2700\,km$^2$}
&
% 40\,GW
& \multicolumn{2}{p{55mm}}{
\mbox{}\raisebox{1pt}{\Gray{\footnotesize -- based\index{Solucar@Sol\'ucar} on {Sol\'ucar}}}
}
\\[7pt]%two_lines
Land in Europe for 1600\,km of
% \par
% \ \ \ HVDC power lines:
&
% (50\,GW capacity)
50\,GW
&
\mbox{}\moneycol{\pounds1\bn}
& \pounds15
% \par -- assuming land costs \pounds7500 per ha in Europe
&
\\
\ \ \ HVDC power lines: \areacol{1200\,km$^2$}
& & \multicolumn{2}{p{55mm}}{
\mbox{}\Gray{\footnotesize -- assuming land costs \pounds7500 per ha }
}
\\[7pt]%three_lines
% & & \multicolumn{2}{p{55mm}}{
% (assuming land costs \pounds7500 per ha in Europe)} \\
2000\,km of
HVDC power lines
&
50\,GW
% capacity
% 1.5b euro from TREC doc page 30 or 190
&
\mbox{}\moneycol{\pounds1\bn}
& \pounds15
% -- based on German Aerospace Center estimates
&
\\[-2pt]
& & \multicolumn{3}{p{75mm}}{
\mbox{}\Gray{\footnotesize -- based on German Aerospace Center {estimates}}
}
\\[7pt]%two_lines
% & & \multicolumn{2}{p{55mm}}{(based on German Aerospace Center estimates)} \\[7pt]
Biofuels:
% 533 sq m per person assuming 30% * 0.5W/mm
\areacol{30\,000\,km$^2$}
% map shows roughly 26260 in england and 5214 in scotland
&
& \multicolumn{2}{c}{\footnotesize{(cost not estimated)}}
&
\mbox{\OliveGreen{2\,kWh/d/p}}
\\[7pt]%[0.1in]
Wood/Miscanthus:
\areacol{31\,000\,km$^2$}
% 5kWh/d per person assuming 0.4 W/mm is 31,000 sq km
% map shows 42,000(with some overlap) + 5,200 sq km,
% but fair to assume 25% of it
% is lost to houses, roads, other farming.
&
& \multicolumn{2}{c}{\footnotesize{(cost not estimated)}} &
\mbox{\OliveGreen{5\,kWh/d/p}}
\\
% & & \multicolumn{2}{p{55mm}}{(based on
% \ind{SELCHP}, which cost \pounds85 million) } \\[0.05in]
\bottomrule
\end{tabular}
}{
\caption[a]{Areas of land and sea required
by \ind{plan M}, and rough costs.
Costs with a question mark are for technologies where no
accurate cost is yet available from prototypes.
``1\,\GWth'' denotes one GW of thermal power.
% for each component.
}\label{tab.planM}
}
\end{table}
I'd like to emphasize that I am not advocating {{this}} particular plan --
it includes several features that I, as dictator of Britain, would not
select. I've deliberately included all available technologies, so that
you can try out your own plans with other mixes.
For example, if you say ``photovoltaics are going to be too expensive,
I'd like a plan with more wave power instead,'' you can see how to do it:
you need to increase the {\wavefarm}s eight-fold.
%
If you don't like the {\windfarm}s' locations, feel free
to move them (but where to?). Bear in mind
that putting more of them offshore will
increase costs.
%
If you'd like fewer {\windfarm}s, no problem -- just specify
which of the other technologies you'd like instead.
You can replace five of the 100\,km$^2$ {\windfarm}s by
adding one more 1\,GW nuclear power station, for example.
Perhaps you think that this plan (like
each of the five plans in
the previous chapter) devotes unreasonably
large areas to
% energy crops (wood,
% miscanthus, and biofuels).
biofuels. Fine: you may therefore conclude
that the demand for liquid fuels for transport
must be reduced below the 2\,kWh per day per person
that this plan assumed; or that liquid fuels
must be created in some other way.
% __billions.tex contains the version of this file from Wed 10/9/08
\section{Cost of switching from fossil fuels to renewables}
Every \index{wind farm}{\windfarm} costs a few million pounds to build
and delivers a few megawatts.
% I'm talking here about the cost of installing the power generators
% (per unit power), not the cost of the delivered energy (per unit energy).
As a very rough ballpark figure in 2008,
installing one watt of capacity costs one pound;
one kilowatt costs 1000 pounds;
a megawatt of wind \ind{cost}s a million;
a gigawatt of nuclear costs a billion or perhaps two.
Other renewables are more expensive.
We (the UK) currently consume a total
power of roughly 300\,GW, most of which is fossil fuel.
So we can anticipate that a major switching from fossil fuel
to renewables and/or nuclear
% or nuclear or both
is going to require roughly 300\,GW of renewables and/or nuclear and thus
have a cost in the ballpark of \pounds300 billion.
The rough costs in \tabref{tab.planM}
add up to \pounds870\bn, with the solar power facilities
dominating the total -- the photovoltaics cost
\pounds190\bn\ and the concentrating solar stations cost
\pounds340\bn. Both these costs might well
come down dramatically as we learn by doing.
% 27+36+15+190+72+8.5+66+15+2.6+21+60+16+2+ 340
% Government sources agree.
A government report leaked by the Guardian in August 2007\nlabel{leakG}
estimates that achieving ``20\% by 2020'' (that is, 20\% of
all energy from renewables, which would require an increase in renewable
power of
% 60\,Mtoe per year, or
80\,GW) could
cost ``up to \pounds22\,billion'' (which
would average out to \pounds1.7\,billion
per year). Even though this estimate is smaller than
the \pounds80 billion that
the rule of thumb I just mentioned would have suggested, the
authors of the leaked report seem to view \pounds22 billion
as an ``unreasonable'' cost,
preferring a target of just 9\% renewables.
% which would cost approximately \pounds4\,billion (\pounds0.3\,billion per year).
(Another reason they give for disliking the ``20\% by 2020'' target is that
the resulting greenhouse gas savings ``risk making the EU
\ind{emissions trading} scheme redundant.'' Terrifying thought!)
\section{Other things that cost a billion}
Billions are big numbers and hard to get a feel for.
To try to help put the cost of kicking fossil fuels into perspective,
let's now list some other things that also come in billions
of pounds, or in \ind{billion}s per year.
% or dollars
I'll also express many of these expenditures ``per person,''
dividing the total by an appropriate population.
Perhaps the most relevant quantity to compare with is the money we
{\em{already}\/} spend on energy every year.
In the UK, the money spent on \index{energy!spending}energy by final users
is \pounds 75\,billion per year, and the total market value
of all energy consumed is \pounds 130\,billion per year.
% DUKES section 1.4:
% market value 131bn
% basic value 70.6bn
So the idea of spending \pounds1.7\,billion
per year on \ind{investment} in future energy infrastructure seems not
at all unreasonable -- it is less than 3\% of our current expenditure
on energy!
Another good comparison to make is with our annual expenditure
on \ind{insurance}: some of the investments we need to make offer
an uncertain return -- just like insurance.
UK individuals and businesses spend \pounds90\bn\ per year
on insurance.
% Source: Association of British Insurers
% www.abi.org.uk
% In the UK, \pounds120\bn\ per year is spent on insurance.
% Nearly A quarter of the net premium is derived from
% overseas business (32 billion income).
% In 2005 the figure was 31.2\bn\ (general) + 87\bn\ (longterm).
% http://www.abi.org.uk/bookshop/researchreports/key%20facts%202005_lr.pdf
\subsection{Subsidies}
\pounds 56\,billion over 25 years: the cost of
\ind{decommissioning} the UK's nuclear power stations.\index{nuclear power!decommissioning}
That's the 2004 figure;
%% in 2006 it was up to \pounds70\,billion.
in 2008 it was up to
\pounds73\,billion
(\pounds 1200 per person in the UK).
\tinyurl{6eoyhg}{http://news.bbc.co.uk/1/hi/uk/7215688.stm}
%% http://www.guardian.co.uk/nuclear/article/0,,1851191,00.html
\subsection{Transport}
\pounds 4.3\,billion: the
cost of \ind{London} \ind{Heathrow Airport}'s Terminal 5.
% http://news.bbc.co.uk/1/low/uk/7294618.stm
(\pounds 72 per person in the UK.)
{% begin troublesomepage hack
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
\noindent
% \subsection{Road-building}
\pounds 1.9\,billion: the
cost of\index{motorway} widening 91\,km of the M1
% through the East
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/M1.eps}}\\
\end{tabular} \\
\end{center}
\caption[a]{The M1, from junction 21 to 30.
}\label{fig.M1}
}%
\begin{figure}[tbp]
\figuremargin{
\begin{center}
{\mbox{\epsfbox{metapost/stacks.441}}} \\
\end{center}
}{
\caption[a]{Things that run into billions.
The scale down the centre has
large ticks at
\$10\,billion intervals and small ticks at
\$1\,billion intervals.
% In order to fit the largest items on the page, there
% is a twenty-fold change in scale at the \$65\bn\ mark.
}\label{Billions}
}
\end{figure}%
%Midlands
(from junction 21 to 30, \figref{fig.M1}).
% , estimated at \pounds 700 million in
%the multi modal study Final Report (December 2001),
% December 2001
% rose to \pounds 1.9 billion
% upon entry into the Targeted Programme of Improvements
% by April 2004
\tinyurl{yu8em5}{http://www.foe.co.uk/resource/reports/paying_for_better_transport.pdf}.
(\pounds 32 per person in the UK.)
%% This is a 271\% cost escalation.
%A further scheme, the A14
%Ellington to Fen Ditton Improvement was originally costed at \pounds
%192 million in the Final Report
%of the Cambridge to Huntingdon Multi Modal Study and is now costed at \pounds 490 million.
%% This represents a 255\% cost escalation.
% From
%% http://www.foe.co.uk/resource/reports/paying_for_better_transport.pdf
%%
% 490 million figure also here
% http://www.bbc.co.uk/cambridgeshire/content/articles/2005/04/05/a14_ellington_feature.shtml
\subsection{Special occasions}
Cost of the London 2012 Olympics:
\pounds 2.4\,billion; no, I'm sorry,
\pounds 5\,billion
\tinyurl{3x2cr4}{http://news.bbc.co.uk/1/hi/england/london/6151176.stm};
% \tinyurl{3yadsp}{http://www.sportinglife.com/london2012/news/story_get.cgi?STORY_NAME=others/06/11/15/manual_134538.html}
or perhaps \pounds 9\,billion
\tinyurl{2dd4mz}{http://news.bbc.co.uk/1/low/uk_politics/6391075.stm}.
% or 9.325. http://news.bbc.co.uk/1/low/uk_politics/7135824.stm
(\pounds 150 per person in the UK.)
\subsection{Business as usual}
\pounds 2.5\,billion/y: \ind{Tesco}'s profits (announced 2007).
% http://news.bbc.co.uk/1/low/business/6557187.stm
(\pounds 42 per year per person in the UK.)
\noindent
\pounds 10.2\,billion/y: spent by British people on {food}\index{waste food}\index{food!waste} that
they buy but do not eat.
% source http://news.bbc.co.uk/1/shared/bsp/hi/pdfs/foodwewaste_fullreport08_05_08.pdf
% \cite{FoodWaste}
(\pounds 170 per year per person in the UK.)
\noindent
\pounds 11\,billion/y:
% (\$22\,bn/y):
\ind{BP}'s profits (2006).
% http://www.bp.com/extendedgenericarticle.do?categoryId=2012968&contentId=7028144
\noindent
\pounds 13\,billion/y:
%(\$25\,bn/y):
Royal Dutch \ind{Shell}'s profits (2006).
% http://news.bbc.co.uk/1/hi/business/6319577.stm
% Most of Shell's profits come from finding and extracting oil,
% and then selling it on to the markets.
% http://news.bbc.co.uk/1/hi/business/4672716.stm
% Little, if any, profit comes from forecourt sales of fuel
\noindent
\$40\,billion/y. \ind{Exxon}'s profits (2006).
%% ($39.5b)
%% http://www.nytimes.com/2007/02/02/business/02oil.html?ex=1328072400&en=08a4aef44d86ae08&ei=5088&partner=rssnyt&emc=rss
\noindent
\$33\,billion/y. World expenditure on \ind{perfume}s and \ind{make-up}.\nlabel{pPerf}
% facial cosmetics.
%\u201cWhat´s the perfumes annual sales worldwide?\u201d
%According to the Worldwatch Institute\u2019s 2004 State of the World
%Report : Consumption by the numbers , annual sales of perfumes are
%$15 billion.
%
%Source:
%State of the World 2004: Consumption by the Numbers
%Date: January 07, 2004
%Table 1-6: Annual Expenditure On Luxury Items Compared With Funding
%Needed To Meet Selected Basic Needs
%Perfumes $15 billion
%\u201cThe global population spends: $18 billion worldwide on facial
%cosmetics, $15 billion on perfumes and $14 billion on ocean cruises.\u201d
%Mongabay.com
% http://www.mongabay.com/external/ocean_ice_cream.htm
\noindent
\$700\,billion per year: USA's expenditure on foreign oil (2008).
% source?
(\$2300 per year per person in the USA.)
}% end troublesoem page hack
\subsection{Government business as usual}
\pounds 1.5\,billion: the
cost of refurbishment of Ministry of
Defence offices. (Private Eye No.\ 1176, 19th January 2007, page 5.)
(\pounds 25 per person in the UK.)
% in Whitehall
\noindent
%\pounds10.6--19.2\,billion
\pounds15\,billion: the cost of introducing UK identity card scheme
%% CUT http://enoughsenough.org/old_power.html
%%
\tinyurl{7vlxp}{http://www.lse.ac.uk/collections/pressAndInformationOffice/newsAndEvents/archives/ 2005/IDCard_FinalReport.htm}.
(\pounds 250 per person in the UK.)
% J. p237 In spite of H, by the time I got here I was bored with the lists of
% items, especially several items of the same type. Suggestion:
% (i) Reduce the list of "other billion things" to one page or so,
% picking out the most interesting ones.
% (ii) Show only the items from (i), in a new Fig 28.2, and remove
% Figs 28.2 and 28.3.
% (iii) Transfer the removed material to the Web site.
\subsection{Planning for the future}
\pounds 3.2\,billion: the
cost of the \ind{Langeled} \ind{pipeline}, which ships gas from
Norwegian producers to Britain.\index{Norway}
The pipeline's capacity is 20 billion m$^3$ per year,
corresponding to a power of 25\,GW\@.
% The pipeline is 1200\,km long and used about
% one million tonnes of steel and one million tonnes of concrete
\tinyurl{6x4nvu}{http://www.statoil.com/statoilcom/svg00990.nsf?opendatabase&artid=F5255D55E1E78319C1256FEF0044704B}
\tinyurl{39g2wz}{http://www.dillinger.de/dh/referenzen/linepipe/01617/index.shtml.en}
\tinyurl{3ac8sj}{http://www.hydro.com/ormenlange/en/}.
%% see costs.tex
(\pounds 53 per person in the UK.)
\subsection{Tobacco taxes and related games}
\pounds 8\,billion/y: annual revenue from tobacco taxes \index{tax}in the UK
%% (2% of UK revenues)
\tinyurl{y7kg26}{http://www.politics.co.uk/issue-briefs/economy/taxation/tobacco-duty/tobacco-duty-$366602.htm}.
(\pounds 130 per year per person in the UK.)
% http://www.politics.co.uk/issue-briefs/economy/taxation/tobacco-duty/tobacco-duty-$366602.htm
The \ind{European Union}\index{subsidy} spends almost \euro1 billion a year subsidising tobacco farming. \myurlb{www.ash.org.uk}{http://www.ash.org.uk/}
% Annual Report 2004-05 and Autumn Performance Report 2005 HM Revenue &
%Customs Presented to Parliament by the Paymaster General by Command of Her
%Majesty, 19 December 2005
%Page 38:
%
%Indirect tax revenue accrued in 2004-05 (?bn)
%Other 8.3
%Alcohol 9.1
%Tobacco 8.1
%Hydrocarbon Oils 23.3
%VAT 74.2
\noindent
\$46\,billion/y: Annual cost of the USA's ``War on drugs.''\index{war!on drugs}
\tinyurl{r9fcf}{http://en.wikipedia.org/wiki/War_on_Drugs}
% includes cost of drug-war actions and the cost of incarcerating people
(\$150 per year per person in the USA.)
\subsection{Space}
\$1.7\,billion: the
%% http://www.nasa.gov/centers/kennedy/about/information/shuttle_faq.html#1
cost of one \ind{space shuttle}.
\marginfignocaption{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/StssstackS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Stssstack.eps}}}%
\\
\end{tabular}
\end{center}
% \caption[a]{}
%% space shuttle: 25\,tons payload to low-earth-orbit. 12\,MN thrust from its solid rocket boosters.
%% Propellant Volume: 535,000 gallon (2,030,000 L) external tank
%% solid rocket Gross Liftoff Weight (per booster): 1.3 million lb (590,000 kg)
%% Gross Liftoff Weight: 4.5 million lb (2.04 million kg)
}
(\$6 per person in the USA.)
\begin{figure}[tbp]
\figuremargin{
\begin{center}
{\mbox{\epsfbox{metapost/stacks.442}}} \\
\end{center}
}{
\caption[a]{A few more things that run into billions.
The vertical scale is squished 20-fold compared with
the previous figure, \figref{Billions}, which is shown
to scale inside the magenta box.
}\label{Billions2}
}
\end{figure}%
\subsection{Banks}
\$700\,billion:
in October 2008, the US government committed \$700\,billion to
bailing out Wall Street, and \ldots
\noindent
\pounds500\,billion:
the UK government committed \pounds500 billion to bailing
out British banks.
% Imagine if just 1\% of this money had been
% invested in renewable energy ten years ago!
\subsection{Military}
\pounds 5\,billion per year: UK's \index{arms exports}arms exports
(\pounds 83 per year per person in the UK),
of which \pounds 2.5\,billion
go to the Middle East, and \pounds 1\,billion go to \ind{Saudi Arabia}.
Source: Observer, 3 December 2006.
\noindent
\pounds 8.5\,billion: cost of
%Allenby/Connaught
redevelopment of army barracks
in Aldershot and Salisbury Plain.
% page 25 of \tinyurlb{33x5kc}{http://www.mod.uk/NR/rdonlyres/95BBA015-22B9-43EF-B2DC-DFF14482A590/0/gep_200708.pdf}
% found from 2ogs5w
(\pounds 140 per person in the UK.)
\noindent
\pounds3.8 billion:
the cost of two new \ind{aircraft carriers} (\pounds 63 per person in the UK).
\myurlb{news.bbc.co.uk/1/low/scotland/6914788.stm}{http://news.bbc.co.uk/1/low/scotland/6914788.stm}
\noindent
\$4.5
billion per year:
{the cost of not making nuclear weapons} --
the US Department of Energy's budget allocates
at least \$4.5
billion per year to ``\ind{stockpile stewardship}" activities to maintain the
\ind{nuclear stockpile} {\em without\/} nuclear testing\index{nuclear!weapon!testing}
and {\em{without}\/} large-scale production of new weapons.
(\$15 per year per person in America.)
\noindent
% The \ind{Trident} \ind{submarine} costs about \$1.9\,billion apiece (not including \ind{warhead}s)
%\myurl{http://www.brook.edu/fp/projects/nucwcost/trident.htm}.
\pounds 10--25 billion: the cost of replacing \ind{Trident},
%
the British nuclear weapon system.
(\pounds 170--420 per person in the UK.)
\tinyurl{ysncks}{http://news.bbc.co.uk/1/low/uk_politics/6205174.stm}.
\noindent
\$63\,billion: American donation of ``\index{military!aid}military aid'' (\ie\
\ind{weapons})
% and weapons
to the Middle East over 10 years -- roughly half to Israel, and half to Arab states.
\tinyurl{2vq59t}{http://www.boston.com/news/globe/editorial_opinion/oped/articles/2007/08/01/the_63_billion_sham/}
(\$210 per person in the USA.)
\noindent
\$1200\,billion per year:
world expenditure on arms\index{world}\index{cost!arms}
% \$1.2 trillion per year (2005 estimate)
\tinyurl{ym46a9}{https://www.cia.gov/cia/publications/factbook/print/xx.html}.
% https://www.cia.gov/cia/publications/factbook/print/xx.html
(\$200 per year per person in the world.)
%K. p241 This para and the preceding 3 x short paras on this page are
% very good, because they illustate that the unachievable expenditure
% of $440bn is, when necessary, perfectly achievable.
\noindent
\$2000\,billion or more: the cost, to the USA,
of the \tinyurl{99bpt}{http://www.guardian.co.uk/Iraq/Story/0,2763,1681119,00.html}
\ind{Iraq war}\index{war!Iraq}
according to Nobel prize-winning economist
Joseph Stiglitz.\index{Stiglitz, Joseph}
%% http://news.bbc.co.uk/1/low/world/americas/7092053.stm
%% 2.76 trillion
(\$7000 per person in America.)
%\pounds8 billion:
%http://www.bloomberg.com/apps/news?pid=20601102&sid=aZiloVkUJNrw&refer=uk
%UK spending on wars in Iraq and \ind{Afghanistan}.
According to the \ind{Stern review}, the global cost of averting dangerous
climate change (if we act now) is \$440\,billion per year
(\$440 per year per person, if shared equally between the 1\,billion
richest people).
In 2005, the US government alone spent \$480\,billion
on \ind{war}s and preparation for wars.\label{pwars}
%% 88kWh per day per person
The total \ind{military}\label{pmili} expenditure of the 15 biggest military-spending
countries was \$840\,billion.
\subsection{Expenditure that does {\textbf{not}} run into billions}
\pounds0.012\,billion per year: the smallest item displayed
in \figref{Billions}
is the
UK government's annual investment in
\index{renewable energy!research and development}renewable-energy
\ind{research and development}.\nlabel{ptinyRd}
(\pounds 0.20 per person in the UK, per year.)
%\subsection{Government investment in renewable-energy-related research and
% development}
%\pounds12.2 million: in 2002--3, the UK Government's commitment to
% renewable-energy-related R\&D was \pounds12.2 million.
% (Source: House of Lords report.)
\small
\section{Notes and further reading}
\beforenotelist
\begin{widenotelist}
\item[\npageref{fig.eng}]
{\nqs{\Figref{fig.eng}.}}
I've assumed that the
solar photovoltaic farms have a power per unit area of 5\,\Wmm,
the same as the Bavaria farm on \pref{pBavaria}, so each farm on the map
delivers 100\,MW on average.
% there are 51 of them
Their total average production would be
5\,GW, which requires roughly 50\,GW of
peak capacity (that's 16 times Germany's PV capacity in 2006).
% was 3\,GW).
% source http://www.rsc.org/chemistryworld/Issues/2008/April/GermanyConsolidatesSolarPowerLead.asp
The yellow hexagons
representing concentrating solar power
have an average power of 5\,GW each;
it takes two of these hexagons to power one of the ``\ind{blob}s'' of \chref{ch.international}.
\item[\npageref{leakG}]
{\nqs{A government report leaked by the Guardian\ldots}}
The Guardian report, 13th August 2007, said
\tinyurl{2bmuod}{http://www.guardian.co.uk/environment/2007/aug/13/renewableenergy.energy}
``Government officials have secretly briefed
ministers that Britain has no hope of getting remotely near the
new European Union renewable energy target that Tony Blair signed
up to in the spring - and have suggested that they find ways of
wriggling out of it.''
The leaked document is at
\tinyurl{3g8nn8}{http://image.guardian.co.uk/sys-files/Guardian/documents/2007/08/13/RenewablesTargetDocument.pdf}.
\item[\pageref{pPerf}]
{\nqs{\ldots perfume\ldots}}
Source: Worldwatch Institute \par
\myurlb{www.worldwatch.org/press/news/2004/01/07/}{http://www.worldwatch.org/press/news/2004/01/07/}
\item[\npageref{pwars}] {\nqs{\ldots wars and preparation for wars \ldots }}
% www.conscienceonline.org.uk
\myurlb{www.conscienceonline.org.uk}{http://www.conscienceonline.org.uk/}
%\setcounter{latestnotepage}{0}% hack to ensure page number given
\item[\npageref{ptinyRd}]
{\nqs{{Government investment in renewable-energy-related research and
development.}}}
In 2002--3, the UK Government's commitment to
renewable-energy-related R\&D was \pounds12.2 million.
Source: House of Lords Science and Technology Committee, 4th Report of Session 2003--04.
% \myurl{http://www.viewsofscotland.org/library/docs/HoL_STC_RE_\%20Practicalities_04.pdf}
% \myurl{http://www.viewsofscotland.org/library/docs/HoL_STC_RE_%20Practicalities_04.pdf}
\tinyurl{3jo7q2}{http://www.viewsofscotland.org/library/docs/HoL_STC_RE_ Practicalities_04.pdf}
Comparably small is
the government's allocation to
% £78.5m to the LCBP over 4 years
the Low Carbon Buildings Programme, \pounds0.018\bn/y
%which amounted to £18m a
%year
shared between wind, biomass, solar hot water/PV,
ground-source heat pumps, micro-hydro and micro CHP\@.
% Global expenditure on climate research: \$2 billion.
%% from mustelid.blogspot (william connoley from BAS)
%UK R+D spend on renewables (2004--5):
%39 million pounds via the research councils and
% 26 million from the DTI capital grant fund
%and
% \$20 million (for renewables) plus \$3.4 million
% for clean coal.
% Grant program for offshore wind (2005--2010):
% \pounds107\,million to support the creation of
% 1\,GW of installed capacity.
\end{widenotelist}
\normalsize
% bail out 700bn $ bail out uk 50bn L bail out northern rock 55 bn pound loan
\yset\chapter{\ycol{What to do now}}
\label{ch.whattodo}
\myquote{Unless we act now, not some time distant
but now, these consequences, disastrous
as they are, will be irreversible. So there
is nothing more serious, more urgent or more demanding of leadership.}%
{Tony Blair,\index{Blair, Tony} 30 October 2006}
% quoted in \tinyurl{yxq5xk}{http://commentisfree.guardian.co.uk/george_monbiot/2007/01/an_open_letter_to_the_prime_mi.html}
% \end{quote}
\myquote{a bit impractical actually\ldots}%
{{Tony Blair}, two months later, \\
\hfill responding to the suggestion that he should {\em{show}\/} \\
\hfill leadership
by not flying to Barbados for holidays.}
% quoted in http://commentisfree.guardian.co.uk/george_monbiot/2007/01/an_open_letter_to_the_prime_mi.html
\label{abia}
% An open letter to the prime minister
%\end{quote}
%Is 'a bit impractical actually' how you'll explain to your grandchildren why you didn't do enough to tackle climate change, Mr Blair?
%George Monbiot
%January 9, 2007 12:30 PM | Printable version
%Dear Tony Blair,
%Last year, you launched the Stern review on climate change with these words: "Unless we act now, not some time distant but now, these consequences, disastrous as they are, will be irreversible. So there is nothing more serious, more urgent or more demanding of leadership." Ten weeks later, you appear to have recanted.
% On Sky News last night, you claimed that it is "a bit impractical actually" to expect people fly less. Instead, we should rely on science to save us, by means that remain mysterious. As for you, you will not be setting an example, by reducing the number of holidays you take at your friends' houses in Florida and the Caribbean. This, too, apparently, would be "unrealistic".
%% My guess is that Blair is making these comments to establish an insanity defence at his war crimes trial.
%People are confused about what they can do. It is individuals as well as
%Governments and corporations who can make a real difference. To make serious
%headway towards smarter lifestyles, we need to start with clear and consistent
% policy and messages, championed both by government and by those outside
% government.
% Tony Blair, September 2004
\noindent
What we should do depends in part on our motivation.
Recall that on page \pageref{sec.why} we discussed three motivations
for getting off fossil fuels: the end of cheap fossil fuels;
security of supply; and climate change.
Let's assume first that we have the climate-change
motivation -- that we want to reduce carbon emissions radically.
(Anyone who doesn't believe in climate change can skip this section and
rejoin the rest of us on page \pageref{welcomeBack}.)
\section{What to do about carbon pollution}
We are not on track to a zero-carbon future.
Long-term investment is not happening.
Carbon sequestration companies are not thriving,
even though the advice from climate experts
and economic experts alike is that sucking
carbon dioxide from thin air will very probably
be necessary to avoid dangerous climate change.
Carbon is not even being captured at any coal power
stations (except for one tiny prototype in Germany).
Why not?
The principal problem is that carbon pollution is
not priced correctly. And there is no
confidence that it's going to be priced correctly
in the future.
When I say ``correctly,'' I mean that the
price of emitting carbon dioxide should be big enough such that
every running coal power station has
carbon capture technology fitted to it.
Solving climate change is a complex topic, but
in a single crude brush-stroke, here is the solution:
the price of carbon dioxide must be such that
people {\em stop burning coal without capture}.
Most of the solution is captured in this one brush-stroke
because, in the long term, coal is the big fossil fuel.
(Trying to reduce emissions from oil and gas is of
secondary importance because supplies of both oil
and gas are expected to decline over the next 50 years.)
So what do politicians need to do? They need to
ensure that all coal power stations have
carbon capture fitted.
% I think the simplest way to achieve this goal
% is to pass a law that says that -- from 2020, say --
% {\em{all coal power stations must use carbon capture}}.
The first step towards this goal
is for government to finance
a large-scale demonstration project
to sort out the technology for carbon capture and storage;
second,
politicians need to change the long-term regulations
for power stations so that the perfected technology is
adopted everywhere.
My simple-minded suggestion for this second step
is to pass a law that says that -- from some date --
{\em{all coal power stations must use carbon capture}}.
% http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/09/25/eacoal125.xml
% the Environment Agency have a similar attitude to new coal
However, most democratic politicians seem to think
that the way to close a stable door is to create a market
in permits-to-leave-doors-open.
\marginfig{\footnotesize
\begin{center}
\mbox{\epsfxsize=53mm\epsfbox{../data/carbon/EUA.eps}} \\
\end{center}
\caption[a]{
A fat lot of good that did!
The price, in euro, of one
% EUA (European Union allowance to emit
ton of \COO\
under the first period of the European emissions trading scheme.
Source: \myurl{www.eex.com}.
} \label{fig.EUA}
}
So, if we conform to the dogma that climate change
should be solved through markets, what's the market-based way to
ensure we achieve our simple goal -- all coal power stations to have
carbon capture?
Well, we can faff around with carbon
% pollution permit
trading --
trading of permits to emit carbon and
of certificates of carbon-capture,
with one-tonne carbon-capture certificates
being convertible into one-tonne carbon-emission permits.
But coal station owners will invest in carbon capture and storage only if
they are convinced that the price of carbon is going
to be high enough for long enough that
carbon-capturing facilities will pay for themselves.
Experts say that a long-term guaranteed carbon price of
something like \$100 per \tonne\ of \COO\ will do the trick.
So politicians need to agree
long-term reductions in \COO\ emissions that are
sufficiently strong that
investors have confidence that the price of
carbon will rise permanently to at least
\$100 per \tonne\ of \COO.
Alternatively they could
issue carbon pollution permits in an auction
with a fixed minimum price. Another way would be
for governments to underwrite investment in
carbon capture by guaranteeing that they will redeem
captured-carbon certificates for \$100 per \tonne\ of \COO,
whatever happens to the market in carbon-emission permits.
I still wonder whether it would be wisest
to close the stable door directly,
rather than fiddling with an international market
that is merely {\em{intended}\/} to encourage stable door-closing.
\begin{figure}[htbp]
\figuremargin{
\begin{center}
\begin{tabular}{cc}
\multicolumn{2}{c}{\mbox{\epsfbox{metapost/stacks.444}}} \\
\end{tabular}
\end{center}
}{
\caption[a]{What price would \COO\ need to have
in order to drive society to make significant changes in \COO\
pollution?
%% emissions?
The diagram shows carbon dioxide costs (per tonne)
at which particular investments will
become economical, or particular behaviours will be significantly impacted,
assuming that a major behavioural impact on activities
like flying and driving results if the
carbon cost doubles the cost of the activity.
As the cost rises through
\$20--70 per tonne, \COO\ would become sufficiently
costly that it would be economical to add
carbon sequestration to new and old power stations.
A price of \$110 per tonne would transform
large-scale renewable electricity-generation
projects that currently cost 3p per kWh more than
gas from pipedreams into financially viable ventures.
For example, the proposed Severn barrage would produce
tidal power with a cost of
% \pounds60 per MWh,
% which is
% \pounds33
% above a typical selling price of
% \pounds27 per MWh;
% if each tidal MWh
% avoided
% one \ton\
% of \COO\ pollution at a value of
% \pounds60 per \tonne,
6p per kWh,
which is
3.3p
above a typical selling price of
2.7p per kWh;
if each 1000\,kWh from the barrage
avoided one \ton\
of \COO\ pollution at a value of
\pounds60 per \tonne,
the Severn barrage would more than pay for itself.
At \$150 per tonne, domestic users of gas would
notice the cost of carbon in their heating bills.
A price of \$250 per tonne would increase the effective cost of
a barrel of oil by \$100.
At \$370, carbon pollution
% emissions
would cost enough
to significantly reduce people's inclination to fly.
At \$500\ per tonne, average
Europeans who didn't change their lifestyle might
spend 12\% of income on
% emission permits to cover
the carbon costs of
driving, flying, and heating
their homes with gas.
And at \$900 per tonne, the carbon cost of
driving would be noticeable.
%At \$90/barrel, the oil industry turns overs \$2.5 trillion/y.
%Each barrel = 0.4\,tCO$_2$, so at \$90/barrel,
%people already pay \Red{\$225} \Blue{to emit 1 ton CO$_2$}.
%(Of course, they are really paying for chemicals and energy,
%not for the right to emit.)
%1700\,kWh per barrel, so oil costs 5.4\,c per kWh.
% 225 * 100 / 90
}
\label{fig.carbonprices}
}
\end{figure}
% \myquote{ Companies and individuals rushing to go green have been spending millions on ``carbon credit" projects that yield few if any environmental benefits. }{ {\em{Financial Times}}, 25th April 2007 }
\myquote{Britain's energy policy just doesn't stack up. It won't deliver
security. It won't deliver on our commitments on climate change. It
falls short of what the world's poorest countries need.}%
{Lord Patten of Barnes, Chair of Oxford University task force\\
\hfill on energy and climate change,
% Monday
4 June 2007.}
%% check the name of the panel
% \end{quote}
\section{What to do about energy supply}
\label{welcomeBack}
Let's now expand our set of motivations, and assume that
we want to get off fossil fuels in order to ensure security of
energy supply.
What should we do to bring about the development of
non-fossil energy supply, and of efficiency measures?
One attitude is ``Just let the market handle it.
As fossil fuels become expensive, renewables and nuclear power
will become relatively cheaper, and the rational consumer will
prefer efficient technologies.''
I find it odd that people have such faith in markets,
given how regularly markets give us things like
booms and busts, credit crunches, and collapses of banks.
Markets may be a good way of making some short-term decisions --
about investments that will pay off within ten years or so -- but
can we expect markets to do a good job of making decisions about energy,
decisions whose impacts last many decades or centuries?
If the free market is allowed to build houses, we end up with
houses that are poorly insulated. Modern houses are only more
energy-efficient thanks to legislation.
The free market isn't responsible for building
roads, railways, dedicated bus lanes, car parks, or cycle paths.
But road-building and the provision of car parks and cycle paths
have a significant impact on people's transport choices.
Similarly, planning laws, which determine {\em where\/} homes and workplaces
may be created and {\em{how densely}\/} houses may be packed into land
have an overwhelming influence on people's future travelling behaviour.
If a new town is created that has no rail station, it is unlikely that
the residents of that town will make long-distance journeys by rail.
If housing and workplaces are more than a few miles apart,
many people will feel that they have no choice but to drive to work.
One of the biggest energy-sinks is the manufacture of stuff;
in a free market, many manufacturers supply us with stuff that
has planned obsolescence, stuff that has to be thrown away and
replaced, so as to make more business for the manufacturers.
So, while markets may play a role, it's silly to say ``let the market
handle it {\em{all}}.'' Surely we need to talk about legislation, regulations,
and taxes.
\subsection{Greening the tax system}
%\input{taxes.tex}
\myquote{
We need to profoundly revise all of our taxes and charges. The aim is to tax pollution
-- notably fossil fuels -- more, and tax work less.}{
Nicolas Sarkozy, President of France
}
%% http://news.bbc.co.uk/1/low/world/europe/7062577.stm
\noindent
At present it's much cheaper
to buy a new microwave, DVD player, or vacuum cleaner
than to get a malfunctioning one fixed.
That's crazy.
This craziness is partly caused by our tax system, which
taxes the labour of the microwave-repair man, and surrounds his
business with time-consuming paperwork. He's doing a {\em{good}\/} thing,
repairing my microwave! -- yet the tax system makes it difficult
for him to do business.
The idea of ``greening the tax system'' is to move taxes
from ``goods'' like labour, to ``bads'' like environmental damage.\nlabel{ETRp}
Advocates of environmental tax reform suggest balancing
% The key to a green tax shift is that it is revenue neutral --
tax cuts on ``goods'' by equivalent tax increases on ``bads,''
so that the tax reforms are revenue-neutral.
\subsection{Carbon tax}
The most important tax to increase, if we want to promote fossil-fuel-free
technologies,
is a tax on carbon. The price of carbon needs to be high enough to
promote investment in alternatives to fossil fuels, and
investment in efficiency measures.
Notice this is exactly the same policy as
was suggested in the previous section. So, whether our motivation is fixing climate
change, or ensuring security of supply, the policy outcome is the same:
we need a carbon price that is stable and high.\nlabel{pCtax}
\Figref{fig.carbonprices} indicates very roughly the various carbon prices
that are required to bring about various behaviour changes and investments; and
the much lower prices charged by organizations that claim to
``offset'' greenhouse-gas emissions.\index{offsetting}\index{carbon offset}\index{carbon neutralization}\index{neutralization, carbon}\index{myth!offsetting}\index{myth!carbon trading}
How best to arrange a high carbon price? Is the European \ind{emissions trading} scheme
(\figref{fig.EUA}) the way to go?
This question lies in the domain of economists
and international policy experts.
The view of Cambridge economists
Michael Grubb and David Newbery\nocite{Newbery08}
\index{Grubb, Michael}\index{Newbery, David}is
that the European emissions trading scheme
is not up to the job --
``current instruments will not deliver an adequate investment response.''
{\tem{The Economist}\/} recommends a carbon tax as the primary mechanism for
government support of clean energy sources.\nlabel{EconoC}
{The Conservative Party's Quality of Life Policy Group} also
recommends increasing environmental taxes and reducing other taxes
-- ``a shift from {\em{pay as you earn}\/} to {\em{pay as you burn}}.''\nlabel{CPetr}
The Royal Commission on Environmental Pollution also says that
the UK should
introduce a carbon tax.
``It should apply upstream and cover all sectors."\nlabel{RCEP}
So, there's clear support for
a big carbon tax, accompanied by reductions in employment taxes, corporation
taxes, and value-added taxes.
But taxes and markets alone are not going to bring about all the actions
needed.
The tax-and-market approach fails
if consumers sometimes choose irrationally,
if consumers value short-term cash more highly than long-term savings,
or if the person choosing what to buy doesn't
pay all the costs associated with their choice.
Indeed many brands are ``{\em{reassuringly expensive}}.''
Consumer choice is not determined solely by price signals.
Many consumers care more about image and perception,
and some deliberately buy expensive.
Once an inefficient thing is bought, it's too late.
It's essential that inefficient things should not be manufactured
in the first place; or that the consumer, when buying, should
feel influenced not to buy inefficient things.
Here are some further examples of failures of the free market.
\subsection{The admission barrier}
Imagine that carbon taxes are sufficiently high that
a new super-duper low-carbon gizmo
would cost 5\% less than its long-standing high-carbon rival,
the Dino-gizmo,
% from Dino-appliances, Inc.,
{\em if\/} it were mass-produced in the
same quantities.
Thanks to clever technology, the Eco-gizmo's carbon emissions
are a fantastic 90\% lower
than the Dino-gizmo's. It's clear that it would be good for
society if everyone bought Eco-gizmos now.
But at the moment,
sales of the new Eco-gizmo are low, so the per-unit economic costs
are higher than the Dino-gizmo's. Only a few tree-huggers
and lab coats will buy the Eco-Gizmo, and
Eco-Gizmo Inc.\ will go out of business.
Perhaps government interventions are necessary to oil
the transition and give innovation a chance. Support for research and
development? Tax-incentives favouring the new product (like the
tax-incentives that oiled the transition from leaded to unleaded
petrol)?
\subsection{The problem of small cost differences}
Imagine that Eco-Gizmo Inc.\ makes it from tadpole to
frog, and that carbon taxes are sufficiently high that
an Eco-gizmo
indeed costs 5\% less than its long-standing high-carbon rival
from Dino-appliances, Inc.
Surely the carbon taxes will now do their job, and all consumers
will buy the low-carbon gizmo?
Ha!
First, many consumers don't care too much about a 5\%
price difference. Image is everything.
Second, if they feel at all threatened by the Eco-gizmo,
Dino-appliances, Inc.\ will relaunch their
Dino-gizmo, emphasizing that it's more patriotic, announcing
that it's now available in green,
and showing cool people sticking with the old faithful
Dino-gizmo. ``Real men buy Dino-gizmos.''
If this doesn't work, Dino will
issue press-releases saying scientists haven't ruled
out the possibility
% suspect that there is a chance
that long-term use of the Eco-gizmo
might cause cancer, highlighting the case of an old lady
who was tripped up by an Eco-gizmo,
or suggesting that Eco-gizmos harm the lesser spotted
fruit bat. Fear, Uncertainty, Doubt.
As a back-up plan, Dino-appliances could always buy
up the Eco-gizmo company.
The winning product will have nothing to do with energy saving
if the economic incentive to the consumer is only 5\%.
How to fix this problem?
Perhaps government should simply ban the sales of the Dino-gizmo (just as
it banned sales of leaded-petrol cars)?
\newcommand{\Debbie}{Tina}%
\newcommand{\Tina}{Tina}%
\subsection{The problem of Larry and \Tina}
Imagine that Larry the landlord rents out a flat to
%% tenant
\Tina\ the
% poverty-stricken
tenant.\index{Tina}\index{Larry}\index{landlord}\index{tenant}
% student.
Larry is responsible for maintaining the flat and providing
the appliances in it, and
\Tina\ pays the monthly heating and electricity bills.
Here's the problem:
Larry feels no incentive to invest in modifications to
the flat that would reduce \Tina's bills.
He could install more-efficient lightbulbs, and
plug in a more economical fridge; these eco-friendly
appliances would easily pay back their extra up-front cost
over their long life; but it's \Tina\
who would benefit, not Larry.
Similarly, Larry feels little incentive to improve the flat's
insulation or install double-glazing, especially when
he takes into account the risk that \Tina's boyfriend Wayne
might smash one of the windows when drunk.
In principle, in a perfect market, Larry and \Tina\ would
both make the ``right'' decisions: Larry would install all the
energy-saving features, and would charge \Tina\ a slightly
higher monthly rent; \Tina\ would recognize that the modern
and well-appointed flat would be cheaper to live in and would thus be
happy to pay the higher rent; Larry would demand an increased deposit in case
of breakage of the expensive new windows; and \Tina\ would
respond rationally and banish Wayne.
However, I don't think that Larry and \Tina\ can ever
deliver a perfect market. \Tina\ is poor, so has difficulty
paying large deposits. Larry strongly wishes to rent out the flat,
so \Tina\ mistrusts his assurances about the property's
low energy bills, suspecting Larry of exaggeration.
So some sort of intervention
is required, to get Larry and \Debbie\ to do the right thing --
for example, government could legislate a huge tax on
inefficient appliances; ban from sale
all fridges that do not meet economy benchmarks;
require all flats to meet high standards of insulation;
or introduce a system of mandatory independent
flat assessment, so that \Debbie\ could read about the flat's
energy profile before renting.
\section{Investment in research and development}
\myquote{
We deplore the minimal amounts that the Government have committed to
renewable-energy-related research and development (\pounds12.2 million in 2002-03).
% ; the comparable figure for the US is \$250 million for 2004-05.
\ldots\ If resources other than wind
are to be exploited in the United Kingdom this has to change.
We could not avoid the conclusion that the Government are not taking
energy problems sufficiently seriously.}{
\ind{House of Lords} Science and Technology Committee
}
% page 7
% refs/HoL_Practicalities_04.pdf
% (4th report of session 2003--04).
% ``Renewable Energy: Practicalities''
\myquote{The absence of scientific understanding often leads to superficial decis\-ion-making. The 2003 energy white paper was a good example of that. I would not like publicly to call it amateurish but it did not tackle the problem in a realistic way.}{Sir David King, former Chief Scientist\index{King, David}}
% http://www.timesonline.co.uk/tol/news/uk/science/article3176458.ece
% director of the new Smith School of Enterprise and the Environment at Oxford University.
\myquote{Serving on the government's Renewables Advisory
Board \ldots\ felt like watching several dozen episodes
of\, {\tem\ind{Yes Minister}\/} in slow motion. I do not think this
government has ever been serious about
renewables.}{Jeremy Leggett, founder of \ind{Solarcentury}\index{Leggett, Jeremy}}
\noindent
I think the numbers speak for themselves.
Just look at \figref{Billions} (\pref{Billions}) and compare the
billions spent on office refurbishments and military toys
with the
% changed from 100 to try to fix OHB
hundred-fold smaller
% \pounds12.2 million per year
commitment to renewable-energy-re\-lat\-ed research and development.
It takes decades to develop renewable technologies such as tidal stream power,
concentrating solar power,
and photovoltaics. Nuclear fusion takes decades too.
All these technologies need up-front support if they are going to succeed.
{% begin troublesomepage hack
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
\section{Individual action}
People sometimes ask me\nocite{JuniperBulbs}
``What should {\em{I}\/} do?''
\Tabref{action8} indicates eight simple personal actions
I'd recommend, and a {\em{very}\/} rough indication of the savings
associated with each action. Terms and conditions apply. Your
savings will depend on your starting point. The numbers in \tabref{action8}
assume the starting point of an above-average consumer.
\begin{table}[htbp]
\figuremargin{
\begin{tabular}{p{3.25in}r} \toprule
Simple action & possible saving \\ \midrule
Put on a woolly jumper and turn
down your heating's thermostat (to 15 or 17\degreesC, say).
Put individual thermostats on all radiators.\index{thermostat}
Make sure the heating's off when no-one's at home.
Do the same at work.
& 20\,kWh/d \\ \\
Read all your\index{meter-reading} meters (gas, electricity, water)
every week, and identify easy
changes to reduce consumption (e.g., switching things off).
Compare competitively with a friend. Read the meters
at your place of work too, creating a perpetual live energy audit.
& 4\,kWh/d \\ \\
Stop flying\index{flight}\index{jet travel}\index{air travel}.
& 35\,kWh/d \\[0.1in]
Drive less\index{car!driving style}\index{car!electric},
drive more slowly, drive more gently, car-pool\index{car!car-pool},
use an electric car, join a car club\index{car!car club},
cycle, walk, use trains and buses\index{public transport}. & 20\,kWh/d \\ \\
% , use the brakes less &
Keep using old gadgets
(\eg\ computers); don't replace them early. & 4\,kWh/d \\ \\
Change lights to fluorescent or LED\@. & 4\,kWh/d \\[0.1in]
Don't buy \ind{clutter}. Avoid \ind{packaging}. & 20\,kWh/d \\[0.1in]
Eat \ind{vegetarian}, six days out of seven. & 10\,kWh/d \\
\bottomrule
\end{tabular}
}{
\caption[a]{Eight simple personal actions.}\label{action8}
}
\end{table}
\medskip
Whereas the above actions are easy to implement, the
ones in \tabref{actionHard} take a bit more planning, determination, and money.
\begin{table}[htbp]
\figuremargin{
\begin{tabular}{p{3.25in}r} \toprule
Major action & possible saving \\ \midrule
Eliminate draughts.\index{draught} & 5\,kWh/d \\
Double glazing. & 10\,kWh/d \\
Improve wall, roof, and floor \ind{insulation}. & 10\,kWh/d \\
Solar hot water panels. & 8\,kWh/d \\
Photovoltaic panels. & 5\,kWh/d\\
Knock down old building and replace by new. & 35\,kWh/d \\
Replace fossil-fuel heating by ground-source
or\par \hspace*{1cm} air-source heat pumps. & 10\,kWh/d\\%$\star$ \\
\bottomrule
\end{tabular}
}{
\caption[a]{Seven harder actions.}\label{actionHard}
}
\end{table}
%$\star$ Heat pumps won't necessarily give a big saving in fossil fuel
%consumption, until the electricity network is decarbonized.
\vfillone
\newpage
Finally, \tabref{tab.Runupaction}
shows a few runners-up: some simple actions with small savings.
\begin{table}[htbp]
\figuremargin{
\begin{tabular}{p{3in}c} \toprule
Action & possible saving \\ \midrule
Wash \ind{laundry} in cold water.
% at 30\degreeC.
& 0.5\,kWh/d \\
Stop using a \ind{tumble-dryer}; use a clothes-line\par \ \ \ or airing cupboard.
& 0.5\,kWh/d \\% bending say 1 per household (375 per y)
\bottomrule
\end{tabular}
}{
\caption{A few more simple actions with small savings.}\label{tab.Runupaction}
}
\end{table}
% Like \citet{JuniperBulbs}, focus on big actions.
}% end hack
\small
\section{Notes and further reading}
\beforenotelist
\begin{widenotelist}
\item[page no.]
\item[\npageref{abia}] {\nqs{``a bit impractical actually"}}
The full transcript of the interview with Tony Blair\index{Blair, Tony}
(9 January 2007)
is here
\tinyurl{2ykfgw}{http://www.guardian.co.uk/environment/2007/jan/09/travelsenvironmentalimpact.greenpolitics}.
Here are some more quotes from it:\par
{\bf{Interviewer:}}
Have you thought of perhaps not flying to \ind{Barbados}
for a holiday and not using all those air miles?\par
{\bf{Tony Blair:}}
I would, frankly, be reluctant to give up my holidays abroad.
\par
{\bf{Interviewer:}}
It would send out a clear message though wouldn't it, if we didn't see that great big air journey off to the sunshine?
\ldots\ -- a holiday closer to home?
\par
{\bf{Tony Blair:}}
Yeah -- but I personally think these things are a bit impractical actually to expect people to do that. I think that what we need to do is to look at how you make air travel more energy efficient, how you develop the new fuels that will allow us to burn less energy and emit less. How -- for example -- in the new frames for the aircraft, they are far more energy efficient.
I know everyone always -- people probably think the Prime Minister
shouldn't go on holiday at all, but I think if what we do in this area
is set people unrealistic targets, you know if we say to people we're
going to cancel all the cheap air travel \ldots\ You know, I'm still
waiting for the first politician who's actually running for office
who's going to come out and say it -- and they're not.
\smallskip
The other quote:
``Unless we act now, not some time distant
but now, these consequences, disastrous
as they are, will be irreversible. So there
is nothing more serious, more urgent or more demanding of \ind{leadership}."
is Tony Blair speaking at the launch of the \ind{Stern review},
30 October 2006
\tinyurl{2nsvx2}{http://www.number-10.gov.uk/output/Page10300.asp}.
See also
\tinyurl{yxq5xk}{http://commentisfree.guardian.co.uk/george_monbiot/2007/01/an_open_letter_to_the_prime_mi.html} for further comment.
\item[\npageref{ETRp}]
{\nqs{Environmental tax reform.}}
See the Green Fiscal Commission,
\myurlb{www.greenfiscalcommission.org.uk}{http://www.greenfiscalcommission.org.uk/}.
\item[\npageref{EconoC}]
{\nqs{{\tem{The Economist}\/} recommends a carbon tax.}}
``Nuclear power's new age,'' {\tem{The Economist}}, September 8th 2007.
\item[\npageref{CPetr}]
{\nqs{The Conservative Party's Quality of Life Policy Group}}
-- \citet{CPetr}.
%\item[\npageref{RCEP}] need ref ***
%THE ROYAL COMMISSION ON ENVIRONMENTAL POLLUTION
% 16 June 2000
\end{widenotelist}
\normalsize
%\chapter{Lifestyle change}
%\chapter{Summary of options}
%\input{summary2.tex}
\yset\chapter{\ycol{Energy plans for Europe, America, and the World}}
\label{ch.world}
\begin{figure}[!b]
\figuremargin{
\hspace*{0mm}% This image has a big white gap at the rhs so DON'T CENTER IT
{\mbox{\epsfxsize=0.9\textwidth\epsfbox{../../data/humandev/En.eps}}}% GDP on log scale
% made by gnu
}{
\caption[a]{Power consumption per capita versus
\ind{GDP}\index{data!energy consumption}\index{world}\index{countries}\index{data!GDP}
per capita, in purchasing-power-parity US dollars.
Data from UNDP Human Development Report, 2007.
Squares show countries having
``high human development;'' circles,
``medium'' or ``low.''
Both variables are on logarithmic scales. \Figref{fig.En2}
shows the same data on normal scales.
}\label{fig.En1}
}
\end{figure}
\Figref{fig.En1} shows the power consumptions of
lots of countries or regions, versus their gross domestic products (GDPs).
It is a widely held assumption that human development and
growth are good things, so when sketching world plans
for sustainable energy I am going to assume that all the countries
with low GDP per capita
are going to progress rightwards in \figref{fig.En1}.
And as their GDPs increase, it's inevitable that their
power consumptions will increase too.
It's not clear what consumption we should plan for, but I
think that the average European level (\europe\,kWh per day per person)
seems a reasonable assumption; alternatively, we could
assume that efficiency measures, like those envisaged
in Cartoon Britain in Chapters \ref{ch.everyBIG}--\ref{ch.costs},
allow all countries to attain a European standard of living
with a lower power consumption. In the consumption plan
% for Cartoon Britain
on \pref{CartoonBritain}, Cartoon Britain's consumption
fell to about \Red{68\,kWh/d/p}.
Bearing in mind that Cartoon Britain doesn't have much industrial
activity, perhaps it would be sensible to assume a
slightly higher target, such as Hong Kong's \Red{80\,kWh/d/p}.
\section{Redoing the calculations for Europe}
Can Europe live on renewables?
% german info http://www.erneuerbare-energien.de/inhalt/5996/
Europe's average population density is roughly half of Britain's,
so there is more land area in which to put enormous renewable
facilities.
The area of the European Union is roughly \areacol{9000\,m$^2$ per person}.
However, many of the renewables have lower power
density in Europe than in Britain: most of Europe has less wind, less wave, and less tide.
Some parts do have more hydro (in Scandinavia and Central Europe);
and some have more solar. Let's work out some rough numbers.
\subsection{Wind}
The heart of continental Europe has lower typical windspeeds
than the British Isles -- in much of Italy, for example, windspeeds
are below 4\,m/s. Let's guess that one fifth of Europe has big enough
wind-speeds for economical {\windhfarm}s, having a power per unit area of
2\,\Wmm, and then assume that we give those regions the same
treatment we gave Britain in \chref{ch.wind}, filling 10\%
of them with {\windfarm}s.
The area of the European Union is roughly 9000\,m$^2$ per person.
% The area of Europe is roughly 14\,000\,m$^2$ per person.
% 74
So wind gives
\[
\frac{1}{5} \times 10\% \times 9000\,\m^2 \times 2\,\Wmm = 360\,\W
% \ \mbox{per person}
\]
which is \OliveGreen{{9\,kWh/d per person}}.
% Europe hydro is (as of 2002) 132\,GW capacity.
\subsection{Hydroelectricity}
% Worldwide, hydroelectricity already contributes
% about 1.4\,kWh/d per person.
% 650 million tonnes oil equivalent.
% For many countries,
% hydro has significant potential.
% Turkey, Sweden, Russia, France, Italy, and
% Austria all generate much more hydro than the UK\@.
Hydroelectric production in Europe totals 590\,TWh/y, or
67\,GW; shared between 500\,million, that's 3.2\,kWh/d per person.
This production is dominated by Norway, France, Sweden, Italy, Austria,
and Switzerland.
% see data/hydro and data/hydroe
% I understand that there's little scope for further expansion of
% hydro in Europe.
If every country doubled its hydroelectric facilities -- which I think would be difficult --
then hydro would give \OliveGreen{6.4\,kWh/d per person}.
% TBC add reference
% sweden has one river/valley unexploited?
% area / people
% 4324782000000/486066000
\subsection{Wave}
Taking the whole
Atlantic coastline (about 4000\,km) and multiplying by an assumed
average production rate of 10\,kW/m, we get {\OliveGreen{2\,kWh/d per person}}.
The Baltic and Mediterranean coastlines have no wave resource worth
talking of.
\subsection{Tide}
Doubling the estimated total resource around the British Isles
(11\,kWh/d per person, from \chref{ch.tide})
to allow for French, Irish and Norwegian tidal resources,
then sharing between a population of 500 million, we get
{\OliveGreen{2.6\,kWh/d per person}}.
The Baltic and Mediterranean coastlines have no tidal resource worth
talking of.
\subsection{Solar photovoltaics and thermal panels on roofs}
Most places are sunnier than the UK,%
\amarginfig{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=53mm\epsfbox{../../images/SolarHeaterGO2S.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/SolarHeaterGO2.jpg.eps}} \\
\end{tabular}
\end{center}
% {\epsfxsize=53mm\epsfbox{../../images/KeeleSolar.eps}} \\
\caption[a]{A solar water heater providing hot water for a family in Michigan.
The system's pump is powered by the small photovoltaic panel
on the left.}\label{SHGO}
}
so solar panels would deliver more power in continental Europe.
10\,m$^2$ of roof-mounted photovoltaic panels would deliver
about {\OliveGreen{7\,kWh/d}} in all places south of the UK\@.
Similarly, 2\,m$^2$ of water-heating panels could deliver on average
\OliveGreen{3.6\,kWh/d}
% I guesstimated this assuming 100 replaced by 140
% in the UK 1mm gives 1.26
of low-grade thermal heat.
(I don't see much point in suggesting having more than 2\,m$^2$ per person
of water-heating panels, since
% \figref{viridian} (\pref{viridian}) shows that
this capacity would already be enough to saturate typical demand for hot water.)
\subsection{What else?}
The total so far is
$9+6.4+2+2.6+7+3.6 = 30.6$\,kWh/d per person.
The only resources not mentioned so far are
geothermal power, and large-scale solar farming (with mirrors, panels,
or biomass).
Geothermal power might work, but it's still in the research stages.
I suggest treating it like fusion power: a good investment, but
not to be relied on.
So what about solar farming?
We could imagine using 5\% of Europe (450\,m$^2$ per person)
for solar photovoltaic farms like the Bavarian one in
\figref{fig.bavaria} (which has a power per unit area of 5\,\Wmm).
This would deliver an average power of
\[
5\,\Wmm \times 450\,\m^2 = \OliveGreen{54\,\mbox{kWh/d per person}}.
\]
Solar PV farming would, therefore, add up to something substantial.
The main problem with photovoltaic panels is their cost.
Getting power during the winter is also a concern!
Energy crops? Plants
capture only 0.5\,\Wmm\ (\figref{fig.plants155}).
Given that Europe needs to feed itself,
the non-food energy contribution from plants in Europe can never be
enormous. Yes, there will be some oil-seed rape here and some
forestry there, but I don't imagine that the total non-food
contribution of plants could be more than
\OliveGreen{12\,kWh/d per person}.
% *** could discuss CSP in europes own deserts.
\subsection{The bottom line}
Let's be realistic. Just like Britain, {\em Europe can't live on its own renewables}.
So if the aim is to get off fossil fuels,
\ind{Europe} needs nuclear power, or solar power in other people's deserts
(as discussed on \pref{libya0}),
or both.
\section{Redoing the calculations for North America}
The average \ind{American}\index{USA}\index{North America}
uses 250\,kWh/d per day.
Can we hit that target with renewables? What if we imagine
imposing shocking efficiency measures
(such as efficient cars and high-speed electric trains)
such that Americans were reduced to the misery of living on the mere \europe\,kWh/d
of an average European or Japanese citizen?
\subsection{Wind}
A study by
\cite{ElliottWindy}
% http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=5252760
% \myurl{http://www.awea.org/policy/ccwp.html}
assessed the wind energy potential of the USA\@.
The windiest spots are in North Dakota, Wyoming, and Montana.
They reckoned that, over the whole country,
435\,000\,km$^2$
% thousand square kilometres
of windy land could be exploited
without raising too many hackles, and that the electricity generated would
be 4600\,TWh per year, which is \OliveGreen{42\,kWh per day per person}
if shared between 300 million people. Their calculations assumed an
average power per unit area of 1.2\,\Wmm, incidentally -- smaller than the 2\,\Wmm\ we
assumed in \chref{ch.wind}.
The area of these {\windfarm}s,
435\,000\,km$^2$, is roughly the same as the area of California.
%# 33871648 423969.58 79.9 California
The amount of wind hardware required (assuming a load factor of 20\%)
would be a capacity of about 2600\,GW, which would be a 200-fold increase in
wind hardware in the USA\@.
% they have 11.6GW at present
\subsection{Offshore wind}
If we assume that
shallow offshore waters with an area equal to the
sum of Delaware
% 6447
and Connecticut
% 14357
(20\,000\,km$^2$, a substantial chunk of all shallow waters on the east coast of the USA)
are filled with
offshore {\windfarm}s having a power per unit area of 3\,\Wmm,
we obtain an average power of
60\,GW\@.\nlabel{pUSoff}
That's \OliveGreen{4.8\,kWh/d per person} if shared between 300 million people.
The wind hardware required would be 15 times the total wind hardware
currently in
the USA\@.
\subsection{Geothermal}
I mentioned the MIT geothermal energy study \citep{MITGeothermal}
in \chref{ch.geothermal}. The authors are upbeat about the potential of geothermal
energy in North America, especially
in the western states where there is more hotter rock.
``With a reasonable investment in R\&D,
% EGS [
enhanced geothermal systems
could provide\index{EGS (enhanced geothermal systems)}
100\,\GWe\ or more of cost-competitive generating capacity in the next 50 years.
Further,
enhanced geothermal systems
provide
a secure source of power for the long term.''
%% Total US electricity is 3600\,TWh/y which is 411 GW average
Let's assume they are right.
100\,GW of electricity is \OliveGreen{8\,kWh/d per person} when shared between 300 million.\label{MITagain}
% popn 106202903 + 32805041 + 295734134 = 434 million
\subsection{Hydro}
% Add US and Canada hydro.
The hydroelectric facilities of \ind{Canada}, the USA, and \ind{Mexico}
generate
about 660\,TWh per year. Shared between 500 million people, that amounts to
{3.6\,kWh/d per person}.
Could the hydroelectric output of North America be doubled? If so, hydro would
provide
\OliveGreen{7.2\,kWh/d per person}.
\subsection{What else?}
The total so far is
$42 + 4.8 +8 + 7.2= 62$\,kWh/d per person. Not enough
for even a
European existence!
I could discuss various other options such as the sustainable burning
of Canadian \ind{forest}s in power stations. But
rather than prolong the agony, let's go immediately for a technology that
adds up: concentrating solar power.
\begin{figure}
\fullwidthfigureright{% added right, Thu 11/9/08
\begin{center}
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/usa2.eps}}\\
\end{center}
}{
\caption[a]{The \ind{little square}\index{square in desert} strikes again.
The 600\,km by 600\,km
square in North America, completely filled with concentrating
solar power, would provide enough power to give 500 million people
the average American's consumption of 250\,kWh/d.
This map also shows the square of size 600\,km by 600\,km in Africa,
which we met earlier.
I've assumed a power per unit area of 15\,\Wmm, as before.
The area of one yellow square is
% the same as the area of Germany,
% and 16 times the area of Wales. Or, to translate into \ind{American},
% it's
a little bigger than the area of \ind{Arizona},
and 16 times the area of \ind{New Jersey}.
Within each big square is a smaller 145\,km by 145\,km square
showing the area required in the desert -- one New Jersey -- to supply
30 million people with 250\,kWh per day per person.
% 60 million people with 125\,kWh per day per person.
}
\label{libya99}
}
\end{figure}%
\Figref{libya99} shows the area within North America that would
provide everyone there (500 million people) with an average power of
\OliveGreen{250\,kWh/d}.
\subsection{The bottom line}
North America's {\em{non-solar}\/} renewables aren't enough for North America to live on.
But when we include a massive expansion of solar power, there's enough.
So North America needs solar in its own deserts,
or nuclear power, or both.\nlabel{pUSall}
\section{Redoing the calculations for the world}
How can 6 billion people obtain the power for a European
standard of living -- 80\,kWh per day per person, say?
\subsection{Wind}
\index{wind}The exceptional spots in the world with strong steady winds are the
central states of the USA (Kansas,
Oklahoma);
Saskatchewan, Canada;
the southern extremities
of Argentina and Chile;
northeast Australia; northeast
and northwest China; northwest Sudan;
southwest South Africa; Somalia;
Iran;
and Afghanistan. And everywhere offshore except for a tropical strip
60 degrees wide centred on the equator.
% north of 30\degrees
% or south of 30\degrees
% is good.
For our global estimate,
% It is estimated that 3\% of the energy from the Sun that hits the earth is converted into wind energy.
%% http://www.esru.strath.ac.uk/EandE/Web_sites/05-06/wind_resource/wndfrm.html
let's go with the numbers from
\ind{Greenpeace} and the \ind{European Wind Energy Association}:
%% http://www.greenpeace.org.uk/contentlookup.cfm?ucidparam=20020619122437&CFID=1044260&CFTOKEN=
``the total available wind resources worldwide are estimated at 53\,000\,TWh per year.''
%% - twice as large as the projection for the world's entire electricity demand in 2020.
That's \OliveGreen{24\,kWh/d per person}.
% That's onshore technically recoverable resource.
%% http://www.erec-renewables.org/documents/EWEA/EWEA.pdf
\subsection{Hydro}
%% How much hydro power could be built at undeveloped sites?
Worldwide, \ind{hydroelectricity} currently contributes
about 1.4\,kWh/d per person.
From the website \myurl{www.ieahydro.org},
``The International Hydropower Association
and the International Energy Agency estimate the world's total technical feasible
hydro potential at 14\,000 TWh/year [6.4\,kWh/d per person on the globe], of which
about 8000\,TWh/year [\OliveGreen{3.6\,kWh/d per person}] is currently considered
economically feasible for development.
% At present about 808 GW (that would be 3.2\,kWh/d per person) in
% operation or under construction.
Most of the potential for
development is in Africa, Asia and Latin America.''\nlabel{worldHyd}
%% with Asia having the
% greatest economically feasible potential at 3600 TWh/year. South
% America has an economically feasible potential of 1600 TWh/year and
% Africa's potential is 1000 TWh/year. In the United States the
% Department of Energy has identified 5,677 sites with undeveloped
% capacity of about 30\,GW\@.
% http://www.springerlink.com/content/r71656674445u558/?p=6a30ecdd013443c98a6f221d4ae87555&pi=10
% saved as tide/Encyc.pdf
% Roger H. Charlier author of a chapter called Tidal Power in
% Encyclopedia of Coastal Science
%
% Re-invention or aggorniamento? tidal power at 30 years
% Pages 271-289 Roger H. Charlier
% Renewable and Sustainable Energy Reviews Volume 1, Issue 4, Dec 1997
% http://www.sciencedirect.com/science?_ob=PublicationURL&_cdi=6163&_pubType=J&_auth=y&_acct=C000050024&_version=1&_urlVersion=0&_userid=994540&md5=82cd56765656ecafed951805599a0155&jchunk=1#1
% saved as
% Lee Kwang Soo et al., 1994. A simple analytical model for the design of the tidal power scheme. Ocean Research, 16(2): 111Â124.
% other people say 3 TW and that much more than 200 GW is harnessable
\subsection{Tide}
There are several places in the world
with tidal\index{tide} resources on the same scale as the Severn estuary (\figref{pBarrage3}).
In \ind{Argentina} there are two sites: San Jos\'e and
Golfo Nuevo;
\ind{Australia} has the Walcott Inlet;
the \ind{USA} \& Canada share the Bay of Fundy;
\ind{Canada} has Cobequid;
% and also Ungava Bay in northern Quebec has one of the world's largest tidal ranges owing to resonance effects
% 16.8 m range off hudson bay
\ind{India} has the Gulf of Khambat;
the USA has Turnagain Arm and Knik Arm;
and \ind{Russia} has Tugur.
And then there is the world's tidal whopper, a place called
Penzhinsk in Russia with a resource of 22\,GW -- ten times as big as the Severn!
%Ten times as big as the Severn:
%Russia: (190\,TWh/y, 22\,GW!).
% Latitude (DMS):61° 0' 0 N Longitude (DMS): 162° 0' 0 E
\cite{Kowalik04} estimates that worldwide, 40--80\,GW of tidal power could
be generated. Shared between 6 billion people, that comes to \OliveGreen{0.16--0.32\,kWh/d per person}.
% He also gives a cheap and cheerful estimate using potential
% energy, amplitude 50\,cm,
% of 8\,TW.
% bottom drag coefficient cd = 3e-3.
% stress = rho cd v**2
% dissipated energy = rho cd v**3
\subsection{Wave}
We can estimate the total extractable power from waves
by multiplying the length of exposed coastlines (roughly 300\,000\,km)
by the typical power per unit length of coastline (10\,kW per metre):
the raw power is thus about 3000\,GW\@.\nlabel{WorldWav}
% See page 3 for beautiful map of wave power in kW/m
% saved as WorldWavePower.pdf
%OK, so wave power is 3000\,GW, which is 0.5\,kW per person, or
%12\,kWh/d per person if perfectly harvested.
Assuming 10\% of this raw power is intercepted by systems
that are 50\%-efficient at converting power to electricity,
wave power could deliver \OliveGreen{0.5\,kWh/d per person}.
\subsection{Geothermal}
According to D.\ H.\ Freeston of the Auckland Geothermal Institute,
\ind{geothermal} power
amounted on average to about
4\,GW, worldwide, in 1995\nlabel{Freeston} --
% 9\,GW total, worldwide.
% Table 1 shows that the installed thermal power is estimated at 8,664
%MWt (1990 = 8,064 MWt) and the energy use is 112,441 TJ/y worldwide.
which is
% 31 billion kWh/y, or
0.01\,kWh/d per person.
%% pr 112441e6/3.6 / 6e9 / 365.25
If we assume that the MIT authors
on \pref{MITagain} were right, and if we assume that
the whole world is like America, then geothermal power offers
\OliveGreen{8\,kWh/d per person}.
\subsection{Solar for energy crops}
People get all excited about energy crops like jatropha, which, it's
claimed, wouldn't need to compete with food for land, because it
can be grown on wastelands.
People need to look at the numbers before they get excited.
The numbers for jatropha are on \pref{pNailJatropha}.
Even if {\em{all}\/} of Africa were completely covered with jatropha
plantations, the power produced, shared between six billion people,
would be {\OliveGreen{8\,kWh/d per person}} (which is only one third of
today's global oil consumption). You can't fix your oil addiction by
switching to jatropha!
Let's estimate a bound on the power that
energy crops could deliver for the whole world, using the same method
we applied to Britain in \chref{ch.solar}: imagine taking all arable land
and devoting it to energy crops.
18\% of the world's land is currently arable or crop land --
%% https://www.cia.gov/cia/publications/factbook/print/xx.html
% Arable land: 13\%;
%% 13.31, 4.71
% permanent crops: 5\%;
% sum = 18\%.
% Total land area is 150 million km$^2$.
%% 148.94
an area of
% All arable and crop land:
27 million km$^2$.
That's \areacol{4500\,m$^2$ per person}, if shared between 6 billion.
% Take over all this land, and
% produce power at {0.5\,W/m$^2$} {flat ground}
%% from biomass.tex \ref{biomasstab}
% or {0.5\,MW/km$^2$}:
Assuming a power per unit area of 0.5\,\Wmm, and losses of
33\% in processing and farming, we find that energy crops, fully taking over
% 13.5\,TW. (Ignoring the energy input required.)
all agricultural land, would deliver \OliveGreen{36\,kWh/d per person}.
Now, maybe this is an underestimate since in \figref{fig.plants155} (\pref{fig.plants155})
we saw that Brazilian sugarcane can deliver a power per unit area
of 1.6\,\Wmm, three times bigger than I just assumed.\nlabel{WorldCrop}
OK, maybe energy crops from Brazil have some sort of future. But I'd like
to move on to the last option.
\subsection{Solar heaters, solar photovoltaics, and concentrating solar power}
Solar\index{solar hot water}\index{thermal solar}
thermal water heaters are a no-brainer. They will work
almost everywhere in the world. China are world leaders in this technology.
There's over 100\,GW of solar water heating capacity worldwide, and more than half of
it is in China.
% The total installed capacity of solar water heating systems as of 2007 is around 154 GW\@. China leads in the utilization of solar water heating systems with installed capacity of 70 GW as of 2006 and a plan to achieve 210 GW by 2020. Israel leads in the per capita usage of solar water heating systems with almost 90% of homes using this system. In the United States, Canada and Australia, solar water heating systems are largely used to heat swimming pools with the installed capacity of 18 GW as of 2005.
% http://ezinearticles.com/?Solar-Power-Hot-Water---The-Future-is-Here!&id=1393865
% Solar hot water/heating capacity increased to an estimated 128 GW globally in 2007, up from 88 GW in 2005, reflecting an annual growth rate of 20 percent over the past two years.
% http://www.i-sis.org.uk/solarPowerToTheMasses.php
% TODO *** check this number and add reference.
% http://news.cnet.com/A-sunny-forecast-for-hot-water/2100-11392_3-6160282.html
% http://www.environmentalgraffiti.com/sciencetech/china-solar-hot-water-capacity-soon-to-be-equivalent-to-40-nuclear-plants/822
% http://www.miller-mccune.com/main/article/171
Solar photovoltaics were technically feasible for Europe,
but I judged them too expensive. I hope I'm wrong, obviously.
It will be wonderful if the cost of photovoltaic power drops in the same
way that the cost of computer power has dropped over the last forty years.
% The same
% This table was copied into solarnotes.tex:
\margintab{
\begin{tabular}{lr} \toprule
Sheffield & 28\% \\ %1230
Edinburgh & 30\% \\
Manchester & 31\% \\
Cork & 32\%\\
London & 34\%\\% 1494
Cologne & 35\%\\% 1534
Copenhagen & 38\%\\% 1644
Munich & 38\% \\% 1680
Paris & 39\%\\
Berlin & 42\%\\
Wellington, NZ & 43\% \\%1900
Seattle & 46\% \\
Toronto & 46\% \\% 2038
%% Almaty 4314N 07656E m ////// Kazakhstan 2200--3000 http://wbln0018.worldbank.org/esmap/site.nsf/files/070-05+RE+Potential+Final+P044440.pdf/$FILE/070-05+RE+Potential+Final+P044440.pdf
% \\%2250 http://www.investkz.com/en/journals/48/104.html
% Kyrgyz Republic has about 2,600
%
Detroit, MI & 54\% \\ %2367 ichigan
Winnipeg & 55\% \\ % http://members.cox.net/weller43/sunshine.htm
Beijing 2403 & 55\% \\%
Sydney 2446 & 56\% \\%
Pula, Croatia & 57\%\\% 2480
Nice, France & 58\%\\%2557
Boston, MA & 58\%\\% 2561 assachusetts
Bangkok, Thailand & 60\%\\% 2648
Chicago & 60\%\\
New York & 61\%\\
Lisbon, Portugal & 61\%\\% 2666
Kingston, Jamaica & 62\%\\% 2709
San Antonio & 62\%\\
Seville, Spain & 66\%\\% 2885
Nairobi, Kenya & 68\%\\% 2983
Johannesburg, SA & 71\%\\% 3126 outh Africa
Tel Aviv & 74\% \\%3250
Los Angeles & 77\%\\
Upington, SA & 91\% \\% 4005 outh Africa
Yuma, AZ & 93\% \\%4055 hours Arizona
Sahara Desert & 98\% \\%4300
\bottomrule
\end{tabular}
\caption[a]{World sunniness figures.\index{data!sunniness}\index{sunshine!data}
\tinyurl{3doaeg}{http://web.archive.org/web/20040401165322/http://members.cox.net/weller43/sunshine.htm}
}
\label{tab.sun}
}
% http://ilx.wh3rd.net/thread.php?msgid=3594984
% http://web.archive.org/web/20060425174023/http://www.members.cox.net/weller43/sunshine.htm
%% http://web.archive.org/web/20040401165322/http://members.cox.net/weller43/sunshine.htm
My guess is that in many regions, the best solar technology for electricity production
will be the concentrating solar power that we discussed on
pages \pageref{FirstCSP} and \pageref{libya99}.
On those pages we already established that
one billion people in Europe and North Africa could be sustained
by country-sized solar power facilities in deserts near the Mediterranean; and that
half a billion in North America could be sustained by Arizona-sized facilities
in the deserts of the USA and Mexico.
I'll leave it as an exercise for the reader to identify
appropriate deserts to help out the other 4.5 billion people in the world.
\subsection{The bottom line}
The non-solar numbers add up as follows.
Wind: 24\,kWh/d/p; hydro: 3.6\,kWh/d/p; tide: 0.3\,kWh/d/p; wave: 0.5\,kWh/d/p;
geothermal:\linebreak 8\,kWh/d/p -- a total of
% 36.4\,kWh/d/p.
36\,kWh/d/p.
Our target was a post-European consumption of 80\,kWh/d per person.
We have a clear conclusion: the non-solar renewables may be ``huge,''
but they are not huge enough. To complete a plan that adds up, we must
rely on one or more forms of solar power.
Or use nuclear power.
Or both.
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pUSoff}]
{\nqs{North American offshore wind resources}.} \newlineone
\myurlb{www.ocean.udel.edu/windpower/ResourceMap/index-wn-dp.html}{http://www.ocean.udel.edu/windpower/ResourceMap/index-wn-dp.html}
\item[\npageref{pUSall}]
{\nqs{North America needs solar in its own deserts,
or nuclear power, or both.}}
To read \ind{Google}'s 2008 plan for a
% 48\% defossilization relative to EIA baseline
40\% defossilization
% relative to today's levels ?IPCC target?
of the USA, see
Jeffery Greenblatt's article {\tem{Clean Energy 2030}\/}
\tinyurl{3lcw9c}{http://knol.google.com/k/-/-/15x31uzlqeo5n/1}.
The main features of this plan are efficiency measures, electrification of
transport, and electricity production from renewables.
% Fossil fuel-based electricity generation by 88%
% Vehicle oil consumption by 38%
% Dependence on imported oil (currently 10 million barrels per day) by 33%
% Electricity-sector CO2 emissions by 95%
% Personal vehicle sector CO2 emissions by 38%
% US CO2 emissions overall by 48% (40% from today's CO2 emission level)
% PEAK capacities
% * 380 gigawatts (GW) wind: 300 GW onshore + 80 GW offshore
% * 250 GW solar: 170 GW photovoltaic (PV) + 80 GW concentrating solar power (CSP)
% * 80 GW geothermal: 15 GW conventional + 65 GW enhanced geothermal systems (EGS)
Their electricity production plan includes
\begin{oldcenter}
\begin{tabular}{rl}
\OliveGreen{10.6\,kWh/d/p}& of wind power,\\
\OliveGreen{2.7\,kWh/d/p}& of solar photovoltaic,\\
\OliveGreen{1.9\,kWh/d/p}& of concentrating solar power,\\
\OliveGreen{1.7\,kWh/d/p}& of biomass,\\
and \OliveGreen{5.8\,kWh/d/p}& of geothermal power\\
\end{tabular}\end{oldcenter}
by 2030.
% load factors
%20% for solar photovoltaics,
%30% for concentrating solar,
%35-40% for wind,
%50% for hydroelectric,
%and
%90% for geothermal, biomass, nuclear and coal.
%Natural gas, which is mostly used for "ramping" purposes
% (increasing or decreasing output quickly according to changing demand) can run up to 90% but is typically operated around 20%.
That's a total of \OliveGreen{23\,kWh/d/p} of new renewables.
They also assume a small increase in nuclear power from
% 100GW to 115GW
\OliveGreen{7.2\,kWh/d/p} to
\OliveGreen{8.3\,kWh/d/p}, and no change in hydroelectricity.
Natural gas would continue to be used, contributing
4\,kWh/d/p.
% see also http://googleblog.blogspot.com/2008/10/clean-energy-2030.html
\setcounter{latestnotepage}{236}% hack to ensure page number not given
\item[\npageref{worldHyd}]
{\nqs{The world's total hydro potential\ldots}} \newlineone
Source: \myurlb{www.ieahydro.org/faq.htm}{http://www.ieahydro.org/faq.htm}.
\item[\npageref{WorldWav}]
{\nqs{Global coastal wave power resource is estimated to be 3000\,GW\@.}}
\par
See \citet{WorldWav}.
%
\item[\npageref{Freeston}]
{\nqs{Geothermal power in 1995.}}
\cite{Freeston}.
\item[\npageref{WorldCrop}]
{\nqs{Energy crops.}}
See \cite{WEAch5} for estimates similar to mine.
\item[Further reading:]
% xpdf ar4-wg3-chapter4.pdf
% Here we discuss energy plans for
% Europe, for North America, and for the world.
{\tem{Nature}\/} magazine has an 8-page article
% managed to do the whole world
discussing how to power the world \citep{NatureWorldElec}.
\end{notelist}
\normalsize
\yset\chapter{\ycol{The last thing we should talk about}}
\label{ch.lastthing}
% see thinair.tex Frank Zeman Columbia
% also http://www.lanl.gov/news/newsbulletin/pdf/Green_Freedom_Overview.pdf
% their capture cost 55 kJ per mol CO2 + 100 kJ of heat
% (cf my limit 37.5 kJ/mol)
% this is before compression to liquid, but they don't do that.
% they need lots of hydrogen because they are about to make CH3OH !!
{\em Capturing \ind{carbon dioxide}
\amarginfignocaption{t}{
\begin{center}
\lowres{\epsfxsize=53mm\epsfbox{../../images/BanksyMaidinlondonSS.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/BanksyMaidinlondon.eps}}%
\end{center}
\label{BanksyMaidinlondon}
}%
from \ind{thin air} is the last thing we should talk about.}\index{carbon capture and storage}\index{sequestration}\index{carbon sequestration}\index{last thing}
When I say this, I am deliberately expressing a double meaning.
First, the energy requirements for carbon capture from
thin air are so enormous, it seems almost absurd to talk about it (and there's
the worry that raising the possibility of fixing climate change by this sort of
\ind{geoengineering} might promote inaction today\index{climate-change inactivists}).
But second, I do think we should talk about it, contemplate how best to
do it, and fund research into how to do it better, because
capturing carbon from thin air may turn out to be our last line of
defense, if climate change is as bad as the climate scientists say,
and if humanity fails to take the cheaper and more sensible options
that may still be available today.
Before we discuss capturing carbon from thin air, we need to understand
the global carbon picture better.
{% begin troublesomepage hack
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.9}
\section{Understanding {\COO}}
\label{sec.whereC}
\noindent
When I first planned this book, my intention was to ignore
\ind{climate change} altogether.\index{carbon dioxide}
In some circles, ``Is climate change happening?'' was a controversial
question. As were ``Is it caused by humans?'' and ``Does it matter?''
And, dangling
at the end of a chain of controversies, ``What should we
do about it?''\label{CControv}
%% was most controversial of all
I felt that sustainable energy was a compelling issue by itself,
and it was best to avoid controversy.
My argument was to be: ``Never mind when fossil fuels
are going to run out; never mind
whether climate change is happening; {\em{burning fossil fuels is
not sustainable anyway}}; let's imagine living sustainably,
and figure out how much sustainable energy is available.''
However, climate change has risen into public
consciousness, and it raises all sorts of interesting
back-of-envelope questions. So I decided to discuss it a
little in the preface and in this closing chapter.
Not a complete discussion, just a few interesting numbers.
\subsection{Units}
% Just as energy is measured in many different units,
% there is no single established unit for quantities of carbon.
Carbon pollution charges are usually measured in dollars
or euros per \tonne\ of \COO, so I'll use the {\dem{\ttonne\ of \COO}}
as the main unit when talking about per-capita carbon
pollution, and the {\dem{\ttonne\ of \COO\ per year}} to measure
rates of pollution. (The average European's greenhouse emissions are
equivalent to 11\,tons per year of \COO; or 30\,kg per day of \COO\@.)
But when talking about carbon in fossil fuels,
vegetation, soil, and water,
I'll talk about \tonnes\ of carbon.
\amarginfig{b}{
\begin{center}
\mbox{\epsfbox{metapost/sign.44}}
\end{center}
\caption[a]{
The weights of an atom of carbon and a molecule of \COO\
are in the ratio 12 to 44, because the carbon atom
weighs 12 units and the two oxygen atoms weigh 16 each.
$12+16+16 = 44$.
}
}%
One \tonne\ of \COO\ contains
$12/44$ \tonnes\ of \ind{carbon}, a bit more than a quarter
of a \tonne.
On a planetary scale,
I'll talk about \gigatonnes\ of carbon (\GtC).
A \ind{gigaton} of carbon is a billion \tonnes.
% also known as
% a \ind{petagram} (Pg). (``Peta'' means $10^{15}$.)
\Gigatonnes\ are hard to imagine, but if you want to bring
it down to a human scale, imagine
burning one \tonne\ of coal (which is what
you might use to heat a house
over a year). Now imagine everyone on the planet
burning one \tonne\ of coal per year: that's 6\,{\GtC} per year,
because the planet has 6 billion people.
\section{Where is the carbon?}
Where is all the carbon?
% And where is the \COO?
We need to know how much is in the oceans, in the ground, and
in vegetation, compared to the atmosphere,
if we want to understand
the consequences of \COO\ emissions.
\begin{figure}[!bp]
\figuremargin{
\begin{center}
{\mbox{\epsfbox{metapost/earth.25}}}
\end{center}
}{
\caption[a]{Estimated amounts of carbon, in \gigatonnes,
in accessible places on the earth.
(There's a load more carbon in rocks too; this carbon moves
round on a timescale of millions of years, with a long-term
balance between carbon in sediment
being subducted at tectonic plate boundaries,
and carbon popping out of
volcanoes from time to time. For simplicity
I ignore this geological carbon.)
% There's not much we can
% do about it, and the average flow is small)
}
\label{carbon}
}
\end{figure}
% \clearpage
%\section{Where is the carbon?}
Figure \ref{carbon} shows where the carbon is.\label{witc}
% how much is in the ground
% http://www.nature.com/nature/journal/v440/n7081/index.html#Review
%\footnote{
%}
%
%How much is in soils, including peatlands and permafrost:
%roughly 3000\,Pg or 3000\,{\GtC}.
%
%see notes
%%% see _co2.tex
Most of it -- 40\,000\,Gt --
is in the ocean (in the form of dissolved \COO\ gas, carbonates,
living plant and animal life, and decaying materials).
Soils and vegetation together contain
about 3700\,Gt.
% 10\% of what's in the oceans.
Accessible fossil fuels -- mainly coal -- contain about 1600\,Gt.
%% half what's in the soils.
Finally, the atmosphere contains about 600\,Gt of carbon.
Until recently, all these pools of carbon were roughly in balance: all
flows of carbon out of a pool (say, soils, vegetation, or
atmosphere) were balanced by equal flows
into that pool. The flows into and out of the fossil fuel pool were both
negligible.
Then humans started burning fossil fuels.
This added two extra {\em{unbalanced}\/} flows, as shown
in \figref{carbon7}.
% \subsection{History of global carbon pollution}
The rate of fossil fuel burning was roughly 1\,{\GtC}/y in 1920,
2\,{\GtC}/y in 1955, and 8.4\,{\GtC} in 2006.\label{hogcp}
(These figures include a small contribution from cement
production, which releases \COO\ from limestone.)
% (Actually, according to the latest papers, emissions in 2006 were
% 9.9\,{\GtC}, of which 8.4\,{\GtC} were fossil fuels.)
%% Tue 23/10/07 UEA/PNAS/BAS
\marginfig{
%\begin{figure}\figuremargin{
\begin{center}
{\mbox{\epsfbox{metapost/earth.24}}}
\end{center}
%}{
\caption[a]{The arrows show two extra carbon flows
produced by burning fossil fuels.
There is an
% net 5\,{\GtC}/y
imbalance between
the 8.4\,{\GtC}/y emissions into the atmosphere from
burning fossil fuels and the 2\,{\GtC}/y
take-up of \COO\ by the oceans.
This cartoon omits the less-well quantified
flows between atmosphere, soil, vegetation, and so forth.
% The other omitted flows between compartments are large,
% and important to an accurate model of climate,
% but I recklessly ignore them.
% I think it would be more reckless to say `the other flows
% between compartments are important and poorly quantified
% and might mitigate the problem created
% by the 5\,{\GtC}/y imbalance'.
}
\label{carbon7}
}
%\end{figure}
How has this significant extra flow of carbon modified
the picture shown in \figref{carbon}?
Well, it's not exactly known. Figure
\ref{carbon7} shows the key things that
{\em{are}\/} known.
Much of
the extra 8.4\,{\GtC} per year that we're putting into the atmosphere
stays in the atmosphere,
raising the atmospheric concentration of carbon-dioxide.
The atmosphere equilibrates fairly rapidly with
the surface waters of the oceans (this equilibration takes only five or ten
years),
and there is a net flow of \COO\ from the
atmosphere into the surface waters of the
oceans, amounting to 2\,{\GtC} per year.
(Recent research indicates this rate of carbon-uptake by the oceans
may be reducing, however.)\nlabel{pCSinkProb}
This unbalanced flow into the surface waters causes
ocean acidification, which is bad news for coral.
%% because of increasing stratification (less mixing) and saturation of
%% surface layer. and increase in temperature.
Some extra carbon is moving into vegetation and soil too,
perhaps about 1.5\,{\GtC} per year,
but these flows are less well measured.
% le quere says Roughly one half of the
% 7\,{\GtC} per year stays in the atmosphere.
Because roughly half of the carbon emissions are staying in the
atmosphere,\nlabel{HalfStay} continued carbon pollution at a
rate of 8.4\,{\GtC} per year will continue to increase \COO\ levels
in the atmosphere, and in the surface waters.
}% end troublesoem page hack
What is the long-term destination of the extra \COO?
Well, since the amount in fossil fuels is so much smaller than the total
in the oceans, ``in the long term''
the extra carbon will make its way into the ocean, and the amounts
of carbon in the atmosphere, vegetation, and soil will return
to normal. However, ``the long term'' means thousands of years.
Equilibration between atmosphere and the {\em{surface}\/} waters is rapid,
as I said,
but figures \ref{carbon} and \ref{carbon7} show a dashed line separating
the surface waters of the ocean from the rest of the ocean.
On a time-scale of 50 years, this boundary is virtually a solid wall.
Radioactive carbon dispersed across the globe by the atomic bomb
tests of the 1960s and 70s has penetrated the oceans
to a depth of only about 400\,m.\label{bombDepth}
In contrast the average depth of the oceans is about 4000\,m.
The oceans circulate slowly: a chunk of deep-ocean water
takes about 1000 years to roll up to the surface\index{ocean conveyor belt}\index{conveyor belt, ocean}
and down again. The circulation of the deep\index{ocean circulation}\index{circulation of oceans}
waters is driven by a combination of temperature gradients and \ind{salinity}
gradients, so it's called the \ind{thermohaline circulation} (in contrast
to the circulations of the surface waters, which are wind-driven).
This slow turn-over of the oceans has a crucial consequence:
we have enough fossil fuels to seriously influence the climate
over the next 1000 years.
\section{Where is the carbon going}
\Figref{carbon7} is a gross simplification.
% In particular, we should show more compartments in the ocean.
For example,
humans are causing additional flows not shown
on this diagram:
the burning of peat and forests in Borneo
in 1997 alone released about
% 2.7\,billion tons of \COO (0.7\,{\GtC}).
0.7\,{\GtC}\@.
%% press release
%% http://www.scidev.net/Features/index.cfm?fuseaction=readFeatures&itemid=337&language=1
%% nature article 10 Nov 2004
%% http://www.nature.com/login/scidev_login.taf?ref=/nature/journal/v432/n7014/full/432144a_fs.html
%% Dr Susan Page, of the University of Leicester, estimates that Southeast Asian peat lands may contain up to 21 percent of the world's land-based carbon. The 1997 fires released 2.67 billion tons of carbon dioxide into the atmosphere.
%%
%% new scientist says
%% The peat bogs of Borneo and the neighbouring territories of Sumatra and Irian Jaya are up to 20 metres deep and cover more than 200,000 square kilometres. They contain 50 billion tonnes or more of carbon - far more than the forests above.
%% http://www.newscientist.com/article.ns?id=dn6613
%% nature news 2004
%% http://www.nature.com/news/2004/041108/pf/432144a_pf.html
%% helpful ipcc table
%% http://www.grida.no/climate/ipcc_tar/wg1/110.htm
%% shows 1.7 emissions from land use change and -1.9 the other way
%% extra flow into terrestrial sinks -- net -0.2.
Accidentally-started fires in coal seams
release about 0.25\,{\GtC} per year.
% are a similar source
% of about 3\% of global \COO\ emissions.
%% 200 Mt per year of coal
%% http://www.minesandcommunities.org/article.php?a=1815
Nevertheless, this cartoon helps us understand roughly what will happen
in the short term and the medium term under various policies.
First, if carbon pollution follows a ``business as usual'' trajectory,
burning another 500\,Gt of carbon over the next 50 years,
we can expect the carbon to continue to
trickle gradually into the surface waters
of the ocean at a rate of 2\,{\GtC} per year.
% initially., and
% perhaps at a rising rate as the atmospheric concentration increases.
By 2055, at least 100\,Gt of the 500 would have gone into the
surface waters, and \COO\ concentrations in the atmosphere
would be roughly double their pre-industrial levels.
\marginfig{
\begin{center}
\mbox{\epsfxsize=53mm\epsfbox{../data/carbonpulse.eps}} \\
\mbox{\epsfxsize=53mm\epsfbox{../data/carbonpulse1000.eps}} \\
\end{center}
\label{fig.carbonpulse}
\caption[a]{
Decay of a small pulse of \COO\ added to today's atmosphere,
according to the Bern model of the carbon cycle.
Source: \citet{Hansen2007}.
}
}
If fossil-fuel burning
% carbon pollution
were reduced to zero in the 2050s,
the 2\,Gt flow from atmosphere to ocean would also
reduce significantly. (I used to imagine that this flow into
the ocean would persist for decades, but that would be true only
if the surface waters were out of equilibrium with the atmosphere;
but, as I mentioned
earlier, the surface waters and the atmosphere reach equilibrium within
just a few years.)
Much of the 500\,Gt we put into
the atmosphere would only gradually drift into the oceans
over the next few thousand years, as the surface
waters roll down and are replaced by new water from the deep.
Thus our perturbation of the carbon concentration
might eventually be righted, but only after thousands of years.
And that's assuming that this large perturbation of the atmosphere
doesn't drastically alter the ecosystem. It's conceivable,
for example,
that the acidification of the surface waters of the ocean might
cause a sufficient extinction of ocean plant-life that a new \ind{vicious cycle}
% positive feedback loop
kicks in: acidification means extinguished plant-life, means
plant-life absorbs less \COO\ from the ocean,
means oceans become even more acidic.
Such \ind{vicious cycle}s (which scientists
call ``\ind{positive feedback}s'' or
``\ind{runaway feedbacks}'')
have happened on earth before: it's believed, for example, that ice ages
ended relatively rapidly because of \ind{positive feedback} cycles in which
rising temperatures caused surface snow and ice
to melt, which reduced the ground's reflection of \ind{sunlight}, which meant the ground
absorbed more heat,
which led to increased temperatures. (Melted \ind{snow} -- water --
is much darker than frozen snow.)\index{albedo flip}
% albedo flip not in text
Another positive feedback possibility to worry about involves \ind{methane hydrates},
which are frozen
in \gigatonne\ quantities in places like Arctic \ind{Siberia},
and in 100-\gigatonne\ quantities on \index{continental shelf}{continental shelves}.
Global warming greater than 1\degreeC\ would possibly melt methane hydrates,
which release methane into the atmosphere, and methane
increases global warming
more strongly than \COO\ does.\nlabel{MethaneH}
% source page 1942
This isn't the place to discuss the uncertainties of
climate change in any more detail.
I highly recommend the books
{\tem{Avoiding Dangerous Climate Change}}
\citep{ADCC06}
and
{\tem{Global Climate Change}} \citep{DesslerParson}.
Also the papers by \cite{Hansen2007} and \citet{NAP79}.
The purpose of this chapter is to discuss the idea of fixing climate
change by sucking carbon dioxide from thin air;
% and in particular
we discuss the energy cost of this sucking next.
\section{The cost of sucking}
Today, pumping carbon out of the ground is big bucks.
In the future,
% assuming that inadequate action is taken now,
perhaps pumping carbon {\em into\/} the ground is going
to be big bucks.
Assuming that inadequate action is taken now to halt global carbon
pollution, perhaps a \ind{coalition of the willing} will in a few decades
pay to create a \ind{giant vacuum cleaner}\index{vacuum cleaner, giant},
and clean up everyone's mess.
Before we go into details of how to capture
carbon from thin air, let's discuss the unavoidable
energy cost of carbon capture.
Whatever technologies we use, they have to respect the laws of physics,
and unfortunately
grabbing \COO\ from thin air and concentrating it
requires energy. The laws of physics say that the
energy required must be at least 0.2\,kWh per kg of \COO\ (\tabref{TheoryCap}).\nlabel{laws0.2kwh}
Given that real processes are typically 35\% efficient at best,
I'd be amazed if the energy cost of carbon capture is ever reduced below
0.55\,kWh per kg.
Now, let's assume that we wish to neutralize a typical European's \COO\
output of 11 \tonnes\ per year, which is 30\,kg per day per person. The
energy required, assuming a cost of 0.55\,kWh per kg of \COO,
is \Red{16.5\,kWh per day per person}.\index{offsetting}\index{carbon offset}\index{carbon neutralization}\index{neutralization, carbon} This is exactly
the same as \Red{British electricity
consumption}. So powering the giant vacuum
cleaner may require us to {\em{double}\/} our electricity production -- or
at least, to somehow obtain extra
power equal to our current electricity production.
If the cost of running giant vacuum cleaners can be brought
down, brilliant, let's make them. But no amount of research and development
can get round the laws of physics, which say that
grabbing \COO\ from thin air and concentrating it
into liquid \COO\ requires at least 0.2\,kWh per kg of \COO\@.
Now, what's the best way to suck CO$_2$ from thin air?
I'll discuss four technologies for building the giant vacuum cleaner:
{\renewcommand{\labelenumi}{\Alph{enumi}.}
\begin{enumerate}% LIST A. B. C. D.
\item chemical pumps;
\item trees;
\item accelerated weathering of rocks;
\item ocean nourishment.
% Current vulcanism, on average,
% emits less than 0.1\,{\GtC} per year.
%% IPClimateChfig3-1aCarbonCyc.gif says <0.1. (and weathering is 0.2)
%% backed up by carbon_cycle_diagram.jpg sedimentation rate 0.2
\end{enumerate}
}
\section{A\@. Chemical technologies for carbon capture}
%% ***
The chemical technologies typically deal with carbon dioxide in two steps.
\begin{oldcenter}
\begin{tabular}{ccccc}
& {\footnotesize concentrate} & & {\footnotesize compress} \\
{0.03\% \COO} &$\longrightarrow$&
{Pure \COO} &$\longrightarrow$&
{Liquid \COO}
\\
\end{tabular}
\end{oldcenter}
First, they {\dem{concentrate}\/} \COO\ from its low concentration
in the atmosphere; then they {\dem{compress}\/} it into a small volume
ready for shoving somewhere (either down a hole in the ground or deep in the ocean\nlabel{shoveOcean}).
Each of these steps has an energy cost.
The costs required by the laws of physics are shown in \tabref{TheoryCap}.
\margintab{
\begin{center}
\begin{tabular}{lc} \toprule
& cost \\
& (kWh/kg) \\ \midrule
concentrate & 0.13 \\
compress & 0.07 \\ \midrule
total & 0.20 \\
\bottomrule
\end{tabular}
\end{center}
\caption[a]{The inescapable energy-cost of concentrating and compressing
\COO\ from thin air.
}\label{TheoryCap}
}%
In 2005, the best published methods for \COO\ capture from thin air
% published in the scientific literature
were quite inefficient: the energy cost was about
3.3\,kWh per kg, with a financial cost of about \$140 per ton of CO$_2$.\nlabel{quiteIneffCCS}
% this cost confirmed by {Herzog03}
At this energy cost, capturing a European's 30\,kg per day would
cost \Red{100\,kWh per day} -- almost the same as
the European's energy consumption of \europe\,kWh per day.
Can better vacuum cleaners be designed?
Recently,
Wallace Broecker, climate scientist,
``perhaps the world's foremost interpreter of the Earth's operation as a biological, chemical, and physical system,''
%% http://www.af-info.or.jp/eng/honor/hot/enrbro.html
has been promoting an as yet unpublished
% the idea that ``artificial trees
%are the way to solve global warming.'' Pushed for details, he says that
%``brilliant physicist Klaus Lackner has invented a method to capture
technology developed by physicist Klaus Lackner for capturing
\COO\ from thin air.\nlabel{pBroeckerKunzig}
% , and it doesn't require very much energy.''
Broecker imagines that the world could carry on burning fossil fuels at much the
same rate as it does now, and 60 million \COO-scrubbers (each the size
of an up-ended shipping container) will vacuum up the \COO\@.
What energy does
Lackner's process require? In June 2007 Lackner told me that his lab
was achieving 1.3\,kWh per kg, but since then they have developed
a new process
based on a resin that absorbs \COO\ when dry and releases \COO\
when moist.
%Moisture can be delivered as water, or as water vapor. In a dry climate it
%+is possible to achieve a CO2 cycle without heating or cooling the material. By exposing the resin to
%+outside air, it will first dry and then absorb CO2. Afterwards the CO2 can be recovered by removing the
%+air from the sorbent chamber (1kJ/mole of CO2) and then exposure to saturated water vapor at ambient
%+temperature. Which leads to a gas mixture rich in CO2 with some water vapor admixed. In a climate where
%+the ambient air is saturated in water vapor, raising the moisture level requires a temperature rise. This
%+of course involves some heat but most of it is recovered in the process, furthermore we are talking about
%+waste heat at 30 to 50C, so it is very cheap energy.
Lackner told me in June 2008 that, in a dry climate,
the concentration cost has been reduced to
% 30-60 kJ per mole is the same as [30 60] * 0.11 / 18.0
about 0.18--0.37\,kWh of low-grade heat per kg \COO\@. The compression cost is 0.11\,kWh per kg.
% The amounts are now down into the 30 to 60 kJ per mole regime of very low grade heat. Of course there is
% +still the compression energy I mentioned the last time. Here we are talking about 15 to 20kJ/mole of
% +electric power.
Thus Lackner's total cost is 0.48\,kWh or less per kg.
For a European's emissions of 30\,kg\,\COO\ per day, we are
still talking about a cost of \Red{14\,kWh per day}, of which \Red{3.3\,kWh per day} would be electricity, and the rest heat.
Hurray for technical progress!
But please don't think that this is a {\em{small}\/} cost. We would require roughly
a 20\% increase in world energy production, just to run the vacuum cleaners.
\section{B\@. What about trees?}
Trees are carbon-capturing systems;
\amarginfignocaption{c}{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm%
\lowres%
{\epsfbox{../../images/nicetreesS.eps}}%
{\epsfbox{../../images/nicetreesM.eps}}%
}\\
\end{tabular} \\
\end{center}\label{Claire92}
%\caption[a]{ } Claire cj
}%
they suck \COO\ out of thin air,
and they don't violate any laws of physics. They are two-in-one machines:
they are carbon-capture facilities powered by built-in solar power stations.
They capture carbon using
energy obtained from sunlight. The fossil fuels that we burn were
originally created by this process. So, the suggestion is, how about
trying to do the opposite of fossil fuel burning? How about creating
wood and burying it in a hole in the ground, while, next door,
humanity continues digging up fossil wood and setting fire to it?
It's daft to imagine creating buried wood at the same time
as digging up buried wood.
Even so, let's work out the land area required to solve the climate
problem with trees.
The best plants in Europe capture carbon at a rate of roughly 10
\tonnes\ of dry wood per hectare\index{hectare}\marginfignocaption{%
1 hectare = 10\,000\,m$^2$
}
per year\nlabel{pSelComTree} -- equivalent
to about 15 \tonnes\ of \COO\ per hectare per year -- so
%So the area of forest per person required
to fix a European's output of 11
\tonnes\ of \COO\ per year we need \areacol{7500 square metres}
of forest per person.
% Taking Britain as an example European country, t
This required
area of 7500 square metres per person
is {\em{twice the area of Britain per person}}.\marginfignocaption{%
the area of Britain per person $\simeq$ 4000\,m$^2$
}
And then you'd have to find somewhere to permanently store 7.5 tons of wood
per person per year!
At a density of 500\,kg per m$^3$, each person's wood would occupy
15\,m$^3$ per year. A lifetime's wood -- which, remember, must be safely stored away
and never burned -- would occupy 1000\,m$^3$. That's five times the entire volume of a typical
house.
% my house is 220 m**3 internal vol.
If anyone proposes using trees to undo climate change, they need to realise that
country-sized facilities are required.
I don't see how it could ever work.
\section{C\@. Enhanced weathering of rocks}
% http://www.realclimate.org/index.php/archives/2008/03/air-capture/#comment-87160
% GRL Cowan
Is there a sneaky way to avoid the significant energy cost of the chemical approach
to carbon-sucking?
Here is an interesting idea: pulverize rocks that
are capable of absorbing \COO, and leave them in the open air.\nlabel{pNaturalSuck}
This idea can be pitched as the acceleration of a natural geological process.
Let me explain.
Two flows of carbon that I omitted
from \figref{carbon7}
are the flow of carbon from rocks into oceans, associated with the natural
weathering of rocks, and the natural precipitation of carbon into marine sediments, which eventually
turn back into rocks. These flows are relatively small, involving about 0.2\,Gt\,C per year
(0.7\,Gt\,\COO\ per year). So they are dwarfed by current human carbon emissions, which are about 40
times bigger. But the suggestion of enhanced-weathering advocates is that we could
fix climate change by speeding up the rate at which rocks are broken down and absorb
\COO\@. The appropriate rocks to break down include \ind{olivine}s or \ind{magnesium silicate}
minerals, which are widespread.
The idea would be to find mines in places surrounded by many square
kilometres of land on which crushed rocks could be spread, or perhaps to spread the crushed rocks directly
on the oceans.
Either way, the rocks would absorb \COO\ and turn into carbonates
and the resulting carbonates would end up being washed into the oceans.
% What effect does that have on the carbon flows in and out of the ocean?
% To pulverized the rocks
To pulverize the rocks
% magnesium silicate minerals sequester \COO\ from plain air, without our adding any energy
% other than the 6\,kJ of electricity per mol of \COO\ pulverization requires.
% (12.7\,kJ/(mol Mg$_2$SiO$_4$), i.e., per two moles \COO\@.)
into appropriately small grains for the reaction with \COO\ to take place
requires only
\Red{0.04\,kWh per kg of sucked \COO}. Hang on, isn't that smaller than the
0.20\,kWh per kg required by the laws of physics? Yes, but nothing is wrong: the rocks themselves
are the sources of the missing energy. Silicates have higher energy than carbonates,
so the rocks pay the energy cost of sucking the \COO\ from thin air.
I like the small energy cost of this scheme but the difficult question is,
who would like to volunteer to cover their country with pulverized rock?
\section{D\@. Ocean nourishment}
One problem with chemical methods, tree-growing methods, and rock-pulver\-iz\-ing methods
for sucking \COO\ from thin air is that all would require a lot of work, and
no-one has any incentive to do it -- unless an international agreement pays
for the cost of carbon capture. At the moment, carbon prices are too low.
A final idea for carbon sucking might sidestep this difficulty. The idea is to
persuade the ocean to capture carbon a little faster than normal
as a by-product of fish farming.
\begin{figure}[!b]
\figuremargin{
\mbox{\epsfig{file=../../images/PUBLICDOMAIN/maps/uksink.eps}}%
}{
\caption[a]{120 areas in the Atlantic Ocean, each 900\,km$^2$ in size.
These make up the estimated area required in order to fix Britain's
carbon emissions by ocean nourishment.
}\label{fig.uksink}
}
\end{figure}
Some regions of the world have food shortages. There are fish shortages in many areas,
because of over-fishing during the last 50 years.
The idea of {\dem{ocean nourishment}\/} is to fertilize the oceans,
supporting the base of the food chain,
enabling the oceans to support more plant life and more fish, and incidentally to
fix more carbon.
Led by Australian scientist Ian Jones,
% 5000 t per day of carbon in 25 * 20 kmkm
% would be 12 Mt of \COO\ in 30km*30km
% 5000 t C per day is the same as about 7M t COO per year
the ocean nourishment engineers would like to pump a nitrogen-containing fertilizer
such as urea into appropriate fish-poor parts of the ocean.
They claim that 900\,km$^2$
% 30\,km $\times$ 30\,km
of ocean can be nourished
% (by pumping urea fertilizer)
to take up about 5\,M\tCOO/y.\nlabel{pUreaNum}
Jones and his colleagues reckon that
the ocean nourishment process is suitable
for any areas of the ocean deficient in nitrogen.
That includes most of the North Atlantic.
Let's put this idea on a map.
UK carbon emissions are about
600\,M\tCOO/y.
So complete neutralization of
UK carbon emissions would require 120 such areas in the ocean.
The map in \figref{fig.uksink} shows these areas to scale alongside the British
Isles. As usual, a plan that actually adds up requires country-sized
facilities! And we haven't touched on how we would make all the required urea.
While it's an untested idea, and currently illegal,
I do find ocean nourishment interesting because, in contrast
to geological carbon storage, it's a technology that might be implemented
even if the international community doesn't agree on a high value
for cleaning up carbon pollution; fishermen might nourish the oceans
purely in order to catch more fish.
\myquote{Commentators can be predicted to oppose manipulations of the ocean, focusing on
the uncertainties rather than on the potential benefits. They will be playing to the
public's fear of the unknown. People are ready to passively accept an escalation of an
established practice (\eg, dumping \COO\ in the atmosphere) while being wary of
innovations that might improve their future well being. They have an uneven
aversion to risk.}{Ian Jones}
\myquote{
We, humanity,
\marginpar{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm\epsfbox{../../images/SeaShell1.jpg.eps}}%
\\
\end{tabular}
\end{center}\label{Claire10}
% \caption[a]{ }
}%
cannot release to the atmosphere
all, or even most, fossil fuel \COO\@. To do so would guarantee
dramatic climate change, yielding a different planet\ldots
}{ \index{Hansen, Jim}{J. Hansen et al} (2007)}
\myquote{
``Avoiding dangerous climate change'' is impossible -- dangerous climate
change is already here. The question is, can we avoid {\bf{catastrophic}\/}
climate change?
}{\index{King, David}David King, UK Chief Scientist, 2007}
\beginfullpagewidth
\small
\section{Notes}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{CControv}]
{\nqs{climate change \ldots\ was a controversial
question}}.
Indeed there still is
a ``yawning gap between mainstream opinion on climate change among the educated elites of Europe and America''
\tinyurl{voxbz}{http://news.bbc.co.uk/1/low/business/6247371.stm}.
\item[\npageref{witc}]
{\nqs{Where is the carbon?}}
Sources:
\cite{ADCC06}, \cite{davidson06:_temper}.
\item[\npageref{hogcp}]
{\nqs{The rate of fossil fuel burning\ldots}}
% {\nqs{History of global carbon pollution.}}
Source: \cite{MarlandBA}.
\item[\npageref{pCSinkProb}]
{\nqs{Recent research indicates carbon-uptake by the oceans
may be reducing}.}
\myurlb{www.timesonline.co.uk/tol/news/uk/science/article1805870.ece}{http://www.timesonline.co.uk/tol/news/uk/science/article1805870.ece}, \myurlb{www.sciencemag.org/cgi/content/abstract/1136188}{http://www.sciencemag.org/cgi/content/abstract/1136188},
\tinyurl{yofchc}{http://news.bbc.co.uk/1/low/uk/7053903.stm},
%% http://lgmacweb.env.uea.ac.uk/e415/publications.html
\citet{lequere07}.
\item[\npageref{HalfStay}]
{\nqs{roughly half of the carbon emissions are staying in the
atmosphere}}.
It takes 2.1 billion tons of carbon in the atmosphere
(7.5\,Gt\,\COO)
to raise the atmospheric \COO\ concentration by one part per million (1\,\ind{ppm}).
If all the \COO\ we pumped into the atmosphere stayed there, the
concentration would be rising by more than 3\,ppm per year --
but it is actually rising at only 1.5\,ppm per year.
% \setcounter{latestnotepage}{0}% hack to ensure page number given
\item[\npageref{bombDepth}]
{\nqs{Radioactive carbon
% dispersed across the globe by the atomic bomb tests of the 1970s
\ldots
has penetrated to a depth of only about 400\,m}.
}
% How big is the `surface'?
The mean value of the penetration depth of bomb $^{14}$C
for all observational sites during the late 1970s is
390$\pm$39\,m (Broecker et al., 1995).
From \tinyurl{3e28ed}{http://www.grida.no/climate/ipcc_tar/wg1/118.htm}.
% http://www.grida.no/climate/ipcc_tar/wg1/118.htm
\item[\npageref{MethaneH}]
{\nqs{Global warming greater than 1\,{\degree}C would possibly melt methane hydrates}}.
Source: \citet[p1942]{Hansen2007}.
\item[\npageref{TheoryCap}]
{\nqs{Table \ref{TheoryCap}. Inescapable cost of concentrating and compressing
\COO\ from thin air.}}
The unavoidable energy requirement to concentrate \COO\
% is identical to the energy to compress \COO\
from 0.03\% to 100\%
at atmospheric pressure is $kT \ln 100/0.03$ per molecule,
% 8.1 kT per molecule
which is \Red{0.13\,kWh per kg}.
The ideal energy cost of compression of \COO\ to 110\,bar (a pressure mentioned
for geological storage) is \Red{0.067\,kWh/kg}. So the total ideal cost of \COO\
capture and compression is \Red{0.2\,kWh/kg}.
% Practical methods will always cost more than the ideal.
According to the
IPCC special report on carbon capture and storage, the practical
cost of the second step, compression of \COO\ to 110\,bar, is
%0.4 GJ per t\COO
\Red{0.11\,kWh per kg}. (0.4 GJ per \tCOO; 18\,kJ per mole \COO; 7\,kT per molecule.)
% 6.85 kT/molecule ACTUAL cost ^^^^
% IDEAL cost VVVVV
% my calcn of the ideal cost to get to 100-200bar:
% 0.0665 kWh per kg.
% From chemicalogic.com I reckon change in U-TS is essentially what we want.
% Using 283K (this neglects the work done for free by the atmosphere)
% H(kJ/kg) P(kPa) rho(kg/mmm) TS(kJ/kg) U=H-P/rho U-TS
% before -10 100 2 0(est) -60 -60
% after -310 20000 1000 -509.4 -330 +179.4
% DIFF 239.4 kJ/kg
% 0.0665 kWh per kg. which is 4.1kT per molecule
% Source: IPCC special report on carbon capture and storage.
% Lackner said free energy cost is 11kJ per mol; I think that was
% using ideal gas approximation and going to 100bar. (which would be 0.067kWh/kg)
\item[\npageref{shoveOcean}]
{\nqs{Shoving the \COO\ down a hole in the ground or deep in the ocean.}}
See \cite{WEAch8} for discussion.
``For a large fraction of injected \COO\ to
remain in the ocean, injection must be at
great depths. A consensus is developing that the best
near-term strategy would be to discharge \COO\
at depths of 1000--1500 metres, which can
be done with existing technology.''
% page 288 or 16 of 57
%facilities are 10 percent of process capital equipment costs. The annual capital charge rate is 11.5 percent. The coal price is $1.00 per gigajoule. The
%annual average capacity factor is 80 percent. All options involving CO2 separation and disposal include the cost of compressing the separated CO2 to
%135 bar plus a cost of $5 per tonne of CO2 ($18 per tonne of carbon) for pipeline transmission and ultimate disposal.
See also the Special Report by the \ind{IPCC}:
\myurlb{www.ipcc.ch/ipccreports/srccs.htm}{http://www.ipcc.ch/ipccreports/srccs.htm}.
\item[\npageref{quiteIneffCCS}]
{\nqs{In 2005, the best methods for carbon capture
were quite inefficient:
the energy cost was about
3.3\,kWh per kg, with a financial cost of about \$140 per ton of CO$_2$.}}
Sources: \citet{KeithEtAl}, \citet{Lackner2}, \citet{Herzog03},
% \citet{IPCC2002:capture},
\citet{Herzog2001:future},
\citet{DavidHerzog2000}.
\item[\npageref{pBroeckerKunzig}]
{\nqs{Wallace Broecker, climate scientist\ldots}}
\myurlb{www.af-info.or.jp/eng/honor/hot/enrbro.html}{http://www.af-info.or.jp/eng/honor/hot/enrbro.html}.
His book promoting \ind{artificial trees}\index{trees!artificial}:
\citet{BroeckerKunzig}.
\item[\npageref{pSelComTree}]
{\nqs{The best plants in Europe capture carbon at a rate of roughly 10
tons of dry wood per hectare per year.}}
Source: Select Committee on Science and Technology.
\item[\npageref{pNaturalSuck}]
{\nqs{Enhanced weathering of rocks.}}
% {pNaturalSuck}
See \cite{Olivine}.
\item[\npageref{pUreaNum}]
{\nqs{Ocean nourishment.}}
See \citet{Judd2008}.
See also \cite{DisOcean}.
The risks of ocean nourishment are
discussed in \citet{Jones2008Risk}.
\end{notelist}
\normalsize
\ENDfullpagewidth
\yset\chapter{\ycol{Saying yes}}
\label{ch.sayingyes}
Because Britain currently gets 90\% of its energy from
fossil fuels, it's no surprise that getting off
fossil fuels requires big, big changes --
a total change in the transport fleet;
a complete change of most building heating systems;
and a 10- or 20-fold increase in green power.
Given the
% current lack of understanding of the size
% of these required changes, and the
general tendency
of the \index{public negativity}public
to say ``no'' to {\windfarm}s,
``no'' to nuclear power, ``no'' to tidal barrages --
``no'' to anything other than fossil fuel power systems --
I am worried that we won't actually get off fossil fuels when we need
to.
Instead, we'll settle for half-measures:
slightly-more-efficient fossil-fuel power stations, cars,
and home heating systems; a fig-leaf of a carbon trading system;
a sprinkling of wind turbines; an inadequate number of nuclear power stations.
% to make a differen.
% I said in the opening of this book that
% I would try to remain neutral, to avoid taking any position
% apart from ``let's look at the numbers''
% and ``we need a plan that adds up.''
%
% But perhaps, for clarity, I should reveal the
% conclusions to which the numbers drive me.
We need to choose a plan that adds up.
It {\em{is}\/} possible to make a plan that adds up,
but it's not going to be easy.
% squabbling
%\section{Stop the Punch and Judy show and get building}
% I think that we should stop arguing about ``renewables {\em or\/}
% nuclear.''
% We should stop the delusion of half-measures.
We need to stop saying no and start saying yes.
We need to stop the \ind{Punch and Judy show} and \ind{get building}.
% I'm happy with any plan that adds up; I suspect that any realistic plan that
% adds up will require us to say yes to {\bf efficiency},
% yes to {\bf renewables}, {\em and\/} yes to
% {\bf nuclear}.
% I even dare to hope that there could be a constructive, cross-party consensus,
% ``Saying Yes,'' embracing these three choices.
% I suggest calling this political movement ``Saying Yes.''
% The goal of ``Saying Yes'' is to quickly sort out a numerate energy policy.
% ``Saying Yes'' doesn't stipulate the details of that policy;
% ``Saying Yes'' expects that any energy policy that adds up will
% have very strong efficiency measures,
% a large increase in renewables (perhaps fifteen-fold),
% and a large increase in nuclear power (perhaps ten-fold).
If you would like an honest, realistic energy policy that adds up, please tell
all your political representatives and prospective political candidates.
% local, national and European elected representatives and prospective political candidates
% \newpage \section{Links} A cross-party group campaigning for Britain to have an energy plan that adds up is {\tem{Serious Change}} -- \myurlb{www.seriouschange.org.uk}{http://www.seriouschange.org.uk/}.
\label{pENDone}
\addtocontents{toc}{\protect\addvspace{10pt}}
\subchaptercontents{Acknowledgments}
% \section{Acknowledgements}
\beginfullpagewidth
For leading me into environmentalism, I thank
Robert MacKay, Gale Ryba, and Mary Archer.
For decades of intense conversation on every detail, thank you to
Matthew Bramley, Mike Cates, and Tim Jervis.
For good ideas, for inspiration, for suggesting good turns of phrase,
for helpful criticism, for encouragement,
I thank the following people, all of whom have shaped this book.
% For helpful conversations and feedback I heartily thank
John Hopfield,
Sanjoy Mahajan,
Iain Murray,
Ian Fells,
Tony Benn,
Chris Bishop,
Peter Dayan,
Zoubin Ghahramani,
Kimber Gross,
% Heliodynamics
Peter Hodgson,
Jeremy Lefroy,
Robert MacKay,
William Nuttall,
Mike Sheppard,
Ed Snelson,
Quentin Stafford-Fraser,
Prashant Vaze,
Mark Warner,
Seb Wills,
Phil Cowans,
Bart Ullstein,
Helen de Mattos,
Daniel Corbett,
Greg McMullen,
Alan Blackwell,
Richard Hills,
Philip Sargent,
Denis Mollison,
Volker Heine,
Olivia Morris,
Marcus Frean,
Erik Winfree,
Caryl Walter,
Martin Hellman,
Per Sillr\'en,
Trevor Whittaker,
Daniel Nocera,
Jon Gibbins,
Nick Butler,
Sally Daultrey,
Richard Friend,
Guido Bombi,
Alessandro Pastore,
%%
John Peacock,
Carl Rasmussen,
Phil C.\ Stuart,
Adrian Wrigley,
Jonathan Kimmitt,
Henry Jabbour,
Ian Bryden,
Andrew Green,
Montu Saxena,
Chris Pickard,
Kele Baker,
Davin Yap,
Martijn van Veen,
Sylvia Frean,
Janet Lefroy,
John Hinch,
James Jackson,
Stephen Salter,
Derek Bendall,
Deep Throat,
Thomas Hsu,
Geoffrey Hinton,
Radford Neal,
Sam Roweis,
John Winn,
Simon Cran-McGreehin,
Jackie Ford,
Lord Wilson of Tillyorn,
%% (scottish hydro) agreed Sloy feasible
Dan Kammen,
Harry Bhadeshia,
Colin Humphreys,
Adam Kalinowski,
Anahita New,
Jonathan Zwart,
John Edwards,
Danny Harvey,
David Howarth,
Andrew Read,
Jenny Smithers,
William Connolley,
Ariane Kossack,
Sylvie Marchand,
Phil Hobbs,
David Stern,
Ryan Woodard,
Noel Thompson,
Matthew Turner,
Frank Stajano,
Stephen Stretton,
Terry Barker,
Jonathan K\"ohler,
Peter Pope,
Aleks Jakulin,
Charles Lee,
Dave Andrews,
Dick Glick,
% Claverton,
Paul Robertson,
J\"urg Matter,
Alan and Ruth Foster,
David Archer,
Philip Sterne,
Oliver Stegle,
Markus Kuhn,
Keith Vertanen,
Anthony Rood,
Pilgrim Beart,
Ellen Nisbet,
Bob Flint,
David Ward,
% "No, I am not pro-nuclear, I am not pro-wind, but I am pro getting
% the facts right"
Pietro Perona,
Andrew Urquhart,
Michael McIntyre,
Andrew Blake,
Anson Cheung,
Daniel Wolpert,
Rachel Warren,
Peter Tallack,
Philipp Hennig,
Christian Steinr\"ucken,
Tamara Broderick,
Demosthenis Pafitis,
David Newbery,
Annee Blott,
Henry Leveson-Gower,
John Colbert,
Philip Dawid,
Mary Waltham,
Philip Slater,
Christopher Hobbs,
Margaret Hobbs,
Paul Chambers,
Michael Schlup,
Fiona Harvey,
Jeremy Nicholson,
Ian Gardner,
Sir John Sulston,
Michael Fairbank,
Menna Clatworthy,
Gabor Csanyi,
Stephen Bull,
Jonathan Yates,
Michael Sutherland,
Michael Payne,
Simon Learmount,
John Riley,
Lord John Browne,
Cameron Freer,
Parker Jones,
Andrew Stobart,
% ferrand
Peter Ravine,
Anna Jones,
Peter Brindle,
Eoin Pierce,
Willy Brown,
Graham Treloar,
Robin Smale,
Dieter Helm,
Gordon Taylor,
Saul Griffith,
David Cebonne,
Simon Mercer,
Alan Storkey,
Giles Hodgson,
Amos Storkey,
Chris Williams,
Tristan Collins,
Darran Messem,
Simon Singh,
Gos Micklem,
Peter Guthrie,
Shin-Ichi Maeda,
Candida Whitmill,
Beatrix Schlarb-Ridley,
Fabien Petitcolas,
Sandy Polak,
Dino Seppi,
Tadashi Tokieda,
Lisa Willis,
Paul Weall,
Hugh Hunt,
% Jeff the NZ bus man
Jon Fairbairn,
% Milo%Gš%@ Koja%Gš%@evi%Gć%@
Milo\v{s} T. Koja\v{s}evi\'c,
% Milos Kojasevic
Andrew Howe,
Ian Leslie,
Andrew Rice,
Miles Hember,
Hugo Willson,
% jersey ^^
Win Rampen,
Nigel Goddard,
Richard Dietrich,
Gareth Gretton,
David Sterratt,
% edinburgh ^^^
Jamie Turner,
Alistair Morfey,
%% ^^^ lotus cars and Cam Consult
Rob Jones,
% Schlumberger, Geothermal
% schlum
Paul McKeigue,
% edin
Rick Jefferys,
% conoco philips
Robin S Berlingo,
% surname ^ not known
Frank Kelly,
Michael Kelly,
Scott Kelly,
Anne Miller,
Malcolm Mackley,
Tony Juniper,
Peter Milloy,
Cathy Kunkel,
% A.\ O.\ Dye,
Tony Dye,
Garry Whatford,
Francis Meyer,
Wha-Jin Han,
Brendan McNamara,
Michael Laughton,
Dermot McDonnell,
John McCone,
Andreas Kay,
John McIntyre,
Denis Bonnelle,
Ned Ekins-Daukes,
John Daglish,
Jawed Karim,
Tom Yates,
Lucas Kruijswijk,
Sheldon Greenwell,
Charles Copeland,
Georg Heidenreich,
Colin Dunn,
Steve Foale,
Leo Smith,
Mark McAndrew,
Bengt Gustafsson,
Roger Pharo,
David Calderwood,
Graham Pendlebury,
Brian Collins,
Paul Hasley,
Martin Dowling,
Martin Whiteland,
Andrew Janca,
Keith Henson,
Graeme Mitchison,
Valerie MacKay,
Dewi Williams,
Nick Barnes,
Niall Mansfield,
Graham Smith,
Wade Amos,
Sven Weier,
Richard McMahon,
Andrew Wallace,
Corinne Meakins, %% DirectorCPRE
%% and renewables east board
Eoin O'Carroll,
Iain McClatchie,
Alexander Ac,
Mark Suthers,
Gustav Grob, %% Swiss, electric cars should have PV roofs for AC and 5% heat from engine for finland
Ibrahim Dincer,
Ian Jones,
Adnan Midilli,
Chul Park, %% orbiting balloons (off by 40) and sail boats for making 1GW (kite)
David Gelder,
Damon Hart-Davis,
George Wallis,
Philipp Sp\"oth,
James Wimberley,
Richard Madeley,
Jeremy Leggett,
Michael Meacher,
Dan Kelley,
Tony Ward-Holmes,
Charles Barton,
Jay Mucha,
Johan Simu,
Stuart Lawrence,
Nathaniel Taylor,
Dickon Pinner,
Michael Davey,
Michael Riedel,
William Stoett,
Jon Hilton,
Mike Armstrong,
Tony Hamilton,
Joe Burlington,
David Howey,
Jim Brough,
Mark Lynas,
Hezlin Ashraf-Ball,
Jim Oswald,
John Lightfoot,
Carol Atkinson,
Nicola Terry,
George Stowell,
Damian Smith,
Peter Campbell,
Ian Percival,
David Dunand,
Nick Cook,
Leon di Marco,
Dave Fisher,
John Cox,
Jonathan Lee,
Richard Procter,
Matt Taylor,
Carl Scheffler,
Roger Sewell,
Shirley Dex,
Chris Burgoyne,
Francisco
% A. T. B. N.
Monteiro,
Ian McChesney,
% added after Thu 27/11/08
Alex White,
and Liz Moyer.
% HERE
% Special thanks to
Thank you all.
For help with finding climate data, I thank Emily Shuckburgh.
I'm very grateful to Kele Baker for gathering the electric car
data in \figref{fig.GWiz}.
I also thank David Sterratt for research contributions,
and Niall Mansfield, Jonathan Zwart, and Anna Jones for excellent editorial
advice.
The errors that remain are of course my own.
I am especially indebted to
Seb Wills, Phil Cowans, Oliver Stegle, Patrick Welche, and Carl Scheffler
for keeping my computers working.
I thank the African Institute for Mathematical Sciences, Cape Town,
and the Isaac Newton Institute for Mathematical Sciences, Cambridge,
for hospitality.
% The data source for figures showing greenhouse gas emissions was the
%Climate Analysis Indicators Tool (CAIT)
%Version 4.0. (Washington, DC: World Resources Institute, 2007).
Many thanks to the Digital Technology Group, Computer Laboratory, Cambridge
and Heriot--Watt University Physics Department
for providing weather data online. I am grateful to Jersey Water
and Guernsey Electricity for tours of their facilities.
Thank you to Gilby Productions
for providing the TinyURL service.
TinyURL is a trademark of Gilby Productions.
Thank you to Eric Johnston and Satellite Signals Limited for providing
a nice interface for maps [\myurlb{www.satsig.net}{http://www.satsig.net/}].
% http://www.satsig.net/maps/satellite-tv-dish-pointing-uk-ireland.htm
Thank you to David Stern for the portrait,
to Becky Smith for iconic artwork,
and to Claire Jervis for the
% black-and-white
photos
on pages
\pageref{Claire7},
\pageref{Claire1},
\pageref{Claire91},
\pageref{Claire3},
\pageref{Claire5},
\pageref{Claire92},
% \pageref{Claire94},
% \pageref{Claire23},
% \pageref{Claire8},
\pageref{Claire2},
and \pageref{Claire22}.
For other photos, thanks to Robert MacKay, Eric LeVin,
Marcus Frean, Rosie Ward, Harry Bhadeshia, Catherine Huang,
Yaan de Carlan, Pippa Swannell, Corinne Le Qu\'er\'e, David Faiman,
Kele Baker,
Tim Jervis, and
anonymous contributors to Wikipedia.
I am grateful to the office of the Mayor of London for providing
copies of advertisements.
%% ing artwork.
The artwork on page \pageref{BanksyMaidinlondon}
is ``Maid in London,''
and on page \pageref{Banksy}, ``Sunflowers,'' by Banksy
\myurlb{www.banksy.co.uk}{http://www.banksy.co.uk/}.
Thank you, Banksy!
Offsetting services were provided by {\tt{cheatneutral.com}}.
This book is written in \LaTeX\ on the Ubuntu GNU/Linux
operating system using free software.
The figures were drawn with {\tt\ind{gnuplot}}
and {\tt\ind{metapost}}. Many of the maps were created with
Paul Wessel and Walter Smith's {\tt\ind{gmt}} software.
Thank you also to Martin Weinelt and OMC\@.
Thank you to Donald Knuth, Leslie Lamport, Richard Stallman, Linus Torvalds,
and all those who contribute to free software.
% GNU/Linux.
Finally I owe the biggest debt of gratitude
to the Gatsby Charitable Foundation, who
supported me and my research group before, during, and after
the writing of this book.
\ENDfullpagewidth
\addtocontents{toc}{\protect\addvspace{10pt}}
%{\pagebreak[4]}
\dvipsb{part two - making a difference}
\cleardoublepage
\bset\part{\bcol{Technical chapters}}
\appendix
\newcommand{\chtweak}{}%\addtocounter{chapter}{1}}
\chtweak\chtweak
\rset\chapter{\rcol{Cars II}}
%\chapter[Cars II]{\mbox{\epsfxsize=4.3in\epsfbox{crosspad/cars2.ps}}}
\label{appA}
\label{ch.cars2}%
\label{ch.car2}
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Peugeot_206_WRCS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Peugeot_206_WRC.jpg.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{A Peugot 206 has a \ind{drag coefficient} of 0.33. Photo by Christopher Batt.
}\label{Peugot206}
}
We estimated that a \ind{car}\index{transport} driven
100\,\km\ uses about 80\,\kWh\ of energy.
Where does this energy go? How does it depend on
properties of the car?
Could we make cars that are 100 times more efficient?
\marginfignocaption{
\fbox{
\begin{minipage}{50mm}
The key formula for most of the calculations in this book is:
\[
\mbox{kinetic energy} = \frac{1}{2} m v^2 .
\]
For example, a car of mass $m = 1000\,\kg$
moving at 100\,\km\ per hour or $v = 28$\,m/s
%% 27.777 etres per second
has an energy of
\[
\frac{1}{2} m v^2 \simeq 390\,000 \,\J \simeq 0.1 \,\kWh .
\]
\end{minipage}
}
}%
\marginfig{
% \begin{figure} \figuremargin{
\begin{center}
\mbox{\mono{\epsfbox{metapost/sign.101}}{\epsfbox{metapost/sign.1}}}
\end{center}
%}{
\caption[a]{Our cartoon:\index{cartoon!car}
a car moves at speed $v$ between stops separated
by a distance $d$.}
}%
% \end{figure}
Let's make a simple cartoon of car-driving, to
describe where the energy goes.
The energy in a typical fossil-fuel car goes to four main destinations, all
of which we will explore:
\ben
\item
speeding up then slowing down using the brakes;
\item
air resistance;
\item
rolling resistance;
\item
heat -- 75\% of the energy is thrown away as heat, because the
energy-conversion chain is inefficient.
% to the radiator
\een
Initially our cartoon will ignore rolling resistance; we'll
add in this effect later in the chapter.
Assume the driver accelerates rapidly up to
a cruising speed $v$, and maintains that speed
for a distance $d$, which is the distance between traffic lights,
stop signs, or congestion events.
%% incidents.
At this point, he slams on the brakes and
turns all his kinetic energy into heat in the brakes.
(This vehicle doesn't have fancy regenerative braking.)
Once he's able to move again, he accelerates back up
to his cruising speed, $v$.
This acceleration gives the car kinetic energy; braking
throws that \ind{kinetic energy} away.
Energy goes not only into the brakes:
while the car is moving, it makes air swirl around.
A car leaves behind it a tube of swirling
air, moving at a speed similar to $v$.
Which of these two forms of energy is
the bigger: kinetic energy of
the swirling air, or heat in the brakes?
Let's work it out.
\begin{itemize}
\item
The car speeds up and slows down once in each duration
$d/v$.
The rate at which energy pours into the brakes is:\index{brakes}
\begin{equation}
\frac{\mbox{kinetic energy}}{\mbox{time between braking events} }
=
\frac{ \frac{1}{2} m_{\rm c} v^2 }{ d/v } =
\frac{ \frac{1}{2} m_{\rm c} v^3 }{ d } ,
\end{equation}
where $m_{\rm c}$ is the mass of the car.
\begin{figure}
\figuremargin{
\begin{center}
\mbox{\epsfbox{crosspad/cars4.ps}}
\end{center}
}{
\caption[a]{A car moving at speed $v$ creates
behind it a tube of swirling air;
the cross-sectional
area of the tube is similar to the
frontal area of the car, and the speed at which air in the tube
swirls is roughly $v$.}
}
\end{figure}
\item
The tube of air created in a time $t$ has a volume $A v t$,
where $A$ is the cross-sectional area of the tube, which
is similar to the area of the front view of the car.
(For a \ind{streamlined} \ind{car},
$A$ is usually a little smaller than the \ind{frontal area}
$A_{\rm car}$, and the ratio
% $\cd$
of the tube's effective cross-sectional area to the
car area is called the \ind{drag coefficient}
$\cd$. Throughout the following equations,
$A$ means the effective area of the
car, $\cd A_{\rm car}$.)%
\marginpar{
\fbox{\small
\begin{minipage}{50mm}
I'm using this formula:
\[
\mbox{mass} = \mbox{density} \times \mbox{volume}
\]
The symbol $\rho$ (Greek letter `rho') denotes the density.
\end{minipage}
}
\label{miniformula}
}
The tube has mass $m_{\rm air} = \rho A v t$
(where $\rho$ is the density of air) and
swirls at speed $v$, so its \ind{kinetic energy} is:
\[
\frac{1}{2} m_{\rm air} v^2 =
\frac{1}{2} \rho
%c_{\rm d}
A v t \, v^2,
\]
and the rate of generation of kinetic energy in \ind{swirling air} is:
\[
\frac{ \frac{1}{2} \rho
% c_{\rm d}
A v t v^2}{t} =
\frac{1}{2} \rho
% c_{\rm d}
A v^3 .
\]
\label{pageAvcubed}
% This is very similar to a formula that we had for windmills!
% (Page \pageref{eq.windpower}.)
\end{itemize}
% SPACE TOO BIG ***
So the total rate of energy production by the car is:
\beq
\begin{array}{rrcl}
& \mbox{power going into brakes} & + &
\mbox{power going into swirling air} \\
&
= \frac{1}{2} m_{\rm c} v^3 /d
& + & \frac{1}{2} \rho A v^3 .
\end{array}
\label{eq.totpow}
\eeq
Both forms of energy dissipation scale as $v^3$.
So this cartoon predicts that a driver who halves his speed $v$ makes
his power consumption $8$ times smaller.\index{energy saving!transport}
If he ends up driving the same total distance, his journey
will take twice as long, but the total energy consumed by
his journey will be four times smaller.
Which of the two forms of energy dissipation -- brakes or air-swirling --
is the bigger?
It depends on the ratio of
\[
(m_{\rm c}/d) \left/ (\rho A) \right. .
\]
If this ratio is much bigger than 1, then more power is
going into brakes; if it is smaller,
more power is going into swirling air.%
\marginfig{
% \begin{figure} \figuremargin{ STOP sign
\begin{center}
\mbox{\mono{\epsfbox{metapost/sign.102}}{\epsfbox{metapost/sign.2}}}
\end{center}
%}{
\caption[a]{To know whether energy consumption is braking-dominated\index{brakes}
or air-swirling-dominated, we compare the mass of the car with
the mass of the \ind{tube of air} between \ind{stop-sign}s.}\label{fig.tubesize}
}% \end{figure}
\marginfig{
%\begin{figure}
%\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
% {\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/carsFordSmart2.eps}}} \\
%{\mbox{\epsfxsize=43mm\epsfbox{../../images/cam/carsTankMini.eps}}} \\
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/carsVWHondaS.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/carsVWHonda.eps}}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{Power consumed by a car
is proportional to its cross-sectional area,
during \ind{motorway driving}, and to its mass, during
town driving. Guess which gets better mileage --
the \index{Volkswagen}VW on the left, or the \ind{spaceship}?
}
}
% \end{figure}
Rearranging this ratio,
it is bigger than 1 if
\[
m_{\rm c} > \rho A d .
\]
Now, $A d$ is the volume of the tube of air swept out from
one stop sign to the next. And $\rho A d$ is the mass of that
tube of air. So we have a very simple situation:
energy dissipation is dominated by kinetic-energy-being-dumped-into-the-brakes if the mass of the car is {\em{bigger}\/}
than the mass
of the tube of air from one stop sign to the next;
and energy dissipation is dominated by making-air-swirl
if the mass of the car is {\em smaller} (\figref{fig.tubesize}).
% that tube of air is bigger than the car's mass.
Let's work out the special distance $d^*$ between stop signs,
below which the dissipation is braking-dominated and above which
it is \ind{air-swirling} dominated (also known as \ind{drag}-dominated).
If the frontal area of the car is:
\[
A_{\rm car} = 2\,\m\:\mbox{wide} \times 1.5\,\m\:\mbox{high}
= 3 \, \m^2
\]
and the \ind{drag coefficient} is $\cd = 1/3$
and the mass is $m_{\rm c} = 1000 \,\kg$
then the special distance is:
%% given by
\[
d^* = \frac{m_{\rm c} }{ \rho \cd A_{\rm car}}
= \frac{ 1000 \,\kg }{1.3\,\kg/ \m^3 \times \frac{1}{3} \times 3 \,\m^2} = 750 \,\m .
\]
So ``city-driving'' is dominated by kinetic energy and braking\index{city driving}\index{driving!city driving}
if the distance between stops is less than 750\,m.
Under these conditions, it's a good idea, if you want to save
energy:
\begin{enumerate}
\item
to reduce the mass of your car;
\item
to get a car with \ind{regenerative brakes}\index{brakes!regenerative} (which roughly
halve the energy lost in
braking -- see \chref{ch.transport}); and
\label{pRegenEff}
\item to drive more slowly.
\end{enumerate}
When the stops are significantly more than 750\,m\ apart, energy dissipation
is drag-dominated.\index{driving!motorway driving}
Under these conditions, it doesn't much matter what your
car weighs.
% how much mass you are transporting in the car.
Energy dissipation will
be much the same whether the car contains one person or six.
% It's all about area and speed.
Energy dissipation can be reduced:
\begin{enumerate}
\item
by reducing the car's \ind{drag coefficient};
\item
by reducing its cross-sectional area; or
\item by driving more slowly.
\end{enumerate}
% (Should I include a drag coefficient? Typical values are $1/3$ or $1/2$.)
The actual energy consumption of the car will be the energy dissipation
in \eqref{eq.totpow}, cranked up by a factor related to the
inefficiency of the engine and the transmission.
Typical petrol engines are about 25\% efficient,\label{pCarEng25}
%%% GET REFERENCE
so of the chemical energy that a car guzzles,\index{engine!exhaust}\index{car!engine efficiency}\index{car!radiator}
three quarters
is wasted in making the car's \ind{exhaust}, \ind{engine} and \ind{radiator} hot, and just one quarter
goes into ``useful'' energy:
\margintab{ \small
% \begin{figure}
\begin{center}
\begin{tabular}{c@{\,$\leftrightarrow$\,}c} \toprule
\multicolumn{2}{c}{\sc Energy-per-distance }\\ \midrule
\begin{tabular}{@{}c@{}}Car \\at 110\,km/h\\
\end{tabular}
& 80\,kWh/(100 km) \\
\begin{tabular}{@{}c@{}}
\index{bicycle}Bicycle \\ at 21\,km/h\\
\end{tabular}
& ${2.4}$\,kWh/(100 km) \\
\bottomrule
\end{tabular}
\medskip
\medskip
\begin{tabular}{ll} \toprule
\multicolumn{2}{c}{{\sc{Planes at 900 km/h }}} \\ \midrule
\ind{A380}\index{airbus A380} & 27\,kWh/100 seat-km\\ \bottomrule
\end{tabular}
\end{center}
% }{
\caption[a]{Facts worth remembering:
car energy consumption.
% (In an earlier chapter the car was
% doing 0.7\,kWh/km, but that was at lower speed.)
}
}
\[
\mbox{total power of car} \simeq 4 \left[
\frac{1}{2} m_{\rm c} v^3 /d
+ \frac{1}{2} \rho A v^3
\right] .
\]
Let's check this theory of cars by
plugging in plausible numbers for
\uk{motorway}{freeway} driving.
Let $v= 70\,\miles \, \per \, \hour = 110 \,\km/\h = 31\,\m/\s$
and
% assume the drag coefficient $\cd=1$, so that $A=\cd A_{\rm car}$ is the
% frontal area of the car.
$A=\cd A_{\rm car} = 1\,$m$^2$.
The power consumed by the engine is estimated to be roughly\label{pageDragCar}
\[
4 \times \frac{1}{2} \rho A v^3 = 2 \times {1.3\,\kg/ \m^3 \times 1 \,\m^2}
\times {( 31\,\m/\s)^3}
= 80 \,\kW.
\label{Poweris80}
\]
If you drive the car at this speed for one hour every day, then you
travel 110\,\km\ and use \Red{80\,kWh} of energy per day. If you drove
at half this speed for two hours per day instead, you would travel
the same distance and use
up \Red{20\,\kWh} of energy. This simple theory seems consistent
with the mileage figures for cars quoted in \chref{ch.car}.
% the
% previous chapter (73\,kWh/day for travelling 100\,km at an
% unspecified typical mix of speeds).
Moreover, the theory gives insight into how
the energy consumed by your car could be reduced.
The theory has a couple of flaws which we'll explore in a moment.
Could we make a new car that consumes 100 times less energy
and still goes at 70\,mph?
{\bf{No}}. Not if the car has the same shape.
On the \uk{motorway}{freeway} at 70\,mph,
the energy is going mainly into making air swirl.
Changing the materials the car is made from makes no difference
to that. A miraculous improvement to the fossil-fuel engine
could perhaps boost its efficiency from
25\% to 50\%, bringing the energy consumption of a fossil-fuelled
car down to
roughly 40\,kWh per 100\,km.
% (Could put electric vehicle information here.)
%% see action.tex
Electric vehicles have some wins:
while the weight of the energy store, per useful kWh stored,
is about 25 times bigger than that of petrol, the weight of an electric engine
can be about 8 times smaller.\nlabel{pElecEnginPowRat} And the energy-chain in an electric car is much more
efficient: electric motors can be 90\% efficient.
{% begin troublesomepage hack
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
We'll come back to electric cars in more detail towards the end of this
chapter.
%
\margintab{
\begin{center}
\begin{tabular}{lc}\toprule
\multicolumn{2}{c}{ \sc Drag coefficients } \\ \midrule
\multicolumn{1}{c}{\sc Cars}\\
% Typical drag coefficient: $\cd=0.3$ for most cars where effort has
% been taken to do a little streamlining.
% For example Renault~25 &% , very ordinary car, has 0.28
Honda Insight& 0.25\\
Prius& 0.26\\
Renault~25 & 0.28\\
Honda Civic (2006)& 0.31\\
VW Polo GTi & 0.32\\%% frontal area 2.04m**2 -- C_x = 0.65
Peugeot 206 & 0.33\\
Ford Sierra & 0.34\\
Audi TT& 0.35\\
Honda Civic (2001)& 0.36\\
Citro\"en 2CV& 0.51 \\
% Audi A2& 0.25--0.28\\
\midrule
\multicolumn{1}{l}{Cyclist}& 0.9 \\ % $\cd=0.9$
\midrule
\multicolumn{1}{l}{Long-distance coach} & 0.425 \\
\midrule
\multicolumn{1}{c}{\sc Planes}\\
Cessna & 0.027 \\ % $\cd=0.027$; learjet $\cd=0.022$;
Learjet & 0.022 \\
Boeing 747 & 0.031 \\ % $\cd=0.031$.
\bottomrule
\end{tabular}
\medskip
\medskip
\begin{tabular}{ll}\toprule
%Typical full-size passenger cars have a drag-area of roughly
\multicolumn{2}{c}{ {\sc Drag-areas} (m$^2$)} \\ \midrule
Land Rover Discovery &
% 17.4 sq ft
1.6\\%\,m$^2$ \\
%% in ft**2
Volvo 740 & 0.81 \\ %% 8.70 1990 Volvo 740 Turbo
{\bf Typical car} & {\bf 0.8} \\
Honda Civic & 0.68\\ %% 7.34 2001 Honda Civic
%% 7.02 1992 BMW 325I
VW Polo GTi & 0.65\\%% frontal area 2.04m**2 -- C_x = 0.6528
%% http://www.carfolio.com/specifications/models/car/?car=143110
Honda Insight & 0.47\\% m$^2$ \\
\bottomrule
\end{tabular}
\end{center}
\caption[a]{Drag coefficients and drag areas.}
}
\subsection{Bicycles and the scaling trick}
Here's a fun question:
what's the energy consumption of a bicycle, in kWh per 100\,km?
Pushing yourself along on a bicycle requires energy for the same
reason as a car: you're making air swirl around.
Now, we could do all the calculations from scratch, replacing
car-numbers by bike-numbers.
But there's a simple trick we can use to get
the answer for the bike from the answer for the car.
The energy consumed by a car, per distance travelled, is
the power-consumption associated with air-swirling,
\[
4 \times \frac{1}{2} \rho A v^3,
\]
divided by the speed, $v$; that is,
\[
\mbox{ energy per distance } =
4 \times \frac{1}{2} \rho A v^2 .
\]
% [Another name for `energy per distance' is 'force'.
The ``$4$'' came from engine inefficiency;
$\rho$ is the density of air;
the area $A = \cd A_{\rm car}$ is the effective frontal area of a car;
and $v$ is its speed.
Now, we can compare a bicycle
with a car by dividing $ 4 \times \frac{1}{2} \rho A v^2$ for the bicycle
by
$4 \times \frac{1}{2} \rho A v^2 $ for the car.
All the fractions and $\rho$s cancel, if
the efficiency of the carbon-powered
bicyclist's engine is similar
to the efficiency of the carbon-powered
car engine (which it is).
% -- that'd be a fun thing to double-check later, but let's assume it is so.
The ratio is:
\[
\frac{\mbox{energy per distance of bike}}
{\mbox{energy per distance of car}}
=
\frac{ \cd^{\rm bike} A_{\rm{bike}} v^2_{\rm{bike}} }
{ \cd^{\rm car} A_{\rm{car}} v^2_{\rm{car}} } .
\]
The trick we are using is called ``scaling.'' If we know how
energy consumption scales with speed and area, then
we can predict energy consumption of objects with completely
different speeds and areas.
Specifically, let's assume that the area ratio is
\[
\frac{ A_{\rm{bike}} }
{ A_{\rm{car}} } = \frac{1}{4} .
\]
(Four cyclists can sit shoulder to shoulder in the width of one car.)
Let's assume the bike is not very well streamlined:
\[
\frac{ \cd^{\rm bike}}
{ \cd^{\rm car}} = \frac{1}{1/3}
\]
And let's assume the speed of the bike is 21\,km/h (13 miles per hour),
so
\[
\frac{ v_{\rm{bike}} }
{ v_{\rm{car}} } = \frac{1}{5} .
\]
Then
\beqa
\frac{\mbox{energy-per-distance of bike}}
{\mbox{energy-per-distance of car}}
&=&
\left(
\frac{ \cd^{\rm bike}}
{ \cd^{\rm car}}
\frac{ A_{\rm{bike}} }
{ A_{\rm{car}} }
\right)
\left( \frac{ v_{\rm{bike}} }
{ v_{\rm{car}} } \right)^2
\\
&=&
\left( \frac{3}{4} \right) \times
\left( \frac{1}{5} \right)^2\\
&=&
\frac{3}{100}
\eeqa
So a cyclist at 21\,km/h consumes about 3\% of the energy per kilometre of
a lone car-driver on the motorway -- about {\bf{2.4\,kWh per 100\,km}}.
% (Put this fact into the main text too.)
If you would like a vehicle whose fuel efficiency is
30 times better than a car's, it's simple: ride a
% well-streamlined
bike.
\begin{table}[!b]
%% bikes
%% http://www.recumbents.com/mars/pages/proj/tetz/other/Crr.html
%% trains and cars
%% http://www.lafn.org/~dave/trans/energy/rail_vs_auto_EE.html#s5
%% typical car tyre: C = 0.010
%% typical truck tyre: C = 0.007
%% rail : C = 0.002
\figuremarginwidecap{%%% sizes determined in cft.sty specialwidtha,b
\begin{tabular}{ll} \toprule
wheel & $C_{\rm{rr}}$ \\
\midrule
train\index{rail}\index{train} (steel on steel)&0.002 \\
\ind{bicycle} \ind{tyre}&0.005 \\
truck rubber tyres &0.007 \\%on smooth road \\
car \ind{rubber} tyres &0.010 \\%on smooth road \\
%% see _cars.tex for notes
\bottomrule
\end{tabular}}{
\caption[a]{% Rolling resistance --
The \ind{rolling resistance}\index{data!rolling resistance}
is equal to the weight multiplied
by the coefficient of rolling resistance, $C_{\rm{rr}}$.
The rolling resistance includes the force due to
wheel flex, friction losses in the wheel bearings, shaking and
vibration of both the roadbed and the vehicle (including energy
absorbed by the vehicle's shock absorbers), and sliding of the
wheels on the road or rail.
The coefficient varies with the quality of the road,
with the material the wheel is made from, and with temperature.
The numbers given here assume smooth roads.
\tinyurl{2bhu35}{http://www.lafn.org/~dave/trans/energy/rail_vs_auto_EE.html}
}
\label{tab.Crr}
}
\end{table}
%
\begin{myfloat}
\begin{center}{\small
\threefigures{
\begin{center}
\mbox{\rotatebox{90}{\footnotesize\sf Energy consumption (kWh/100\,km)}\hspace*{8mm}%
{\epsfxsize=40mm\epsfbox{../data/carsTheory.eps}}%
}%
\\[0.2in]
{\sf{speed (km/h)}}\\
\end{center}
}{
\caption[a]{Simple theory of car
fuel consumption (energy per distance)
when driving at steady speed.
% Horizontal axis is speed in km/h.
% Vertical axis is fuel consumption in kWh per 100\,km.
Assumptions: the car's engine uses energy with
an efficiency of 0.25, whatever the
speed; $\cd A_{\rm car} = 1$\,m$^2$;
$m_{\rm car} = 1000\,\kg$; and $C_{\rm{rr}}=0.01$.
% the air resistance has an energy demand that grows
% as the square of the speed,
% and the rolling resistance makes a constant
% energy demand, whatever the speed.
} \label{fig.carsTheory}
}
%% figure 2
{
\begin{center}
\mbox{\ \ \epsfxsize=40mm\mono%
{\epsfbox{../data/mono/bikeTheory.eps}}%
{\epsfbox{../data/bikeTheory.eps}}%
}\\[0.2in]
{\sf{speed (km/h)}}\\
\end{center}
\label{fig.bikeTheory}
}{
\caption[a]{
Simple theory of bike\index{transport!efficiency!bicycle}
fuel consumption (energy per distance).\index{cartoon!bicycle}
% Horizontal axis is speed in km/h.
Vertical axis is energy consumption in
kWh per 100\,km.
Assumptions: the bike's engine (that's you!)
uses energy with an efficiency of 0.25,\nlabel{pBikeCrr};
% source \cite{Prampero}
% whatever the speed;
the drag-area of the cyclist is 0.75\,m$^2$;
the cyclist+bike's mass is
$90\,\kg$; and
$C_{\rm{rr}}=0.005$.
}
}
% figure 3
{
\begin{center}
\mbox{\rotatebox{90}{\footnotesize\sf Energy consumption (kWh/100\,pkm)}\hspace*{8mm}%
{\epsfxsize=40mm\epsfbox{../data/trainTheory8.eps}}%
}%
\\[0.2in]
{\sf{speed (km/h)}}\\
\end{center}
}{
\caption[a]{Simple theory of train\index{rail}\index{train}
energy consumption, {\em{per passenger}},
for an eight-carriage train carrying 584 passengers.
% Horizontal axis is speed in km/h.
Vertical axis is energy consumption in kWh per 100\,\pkm.
Assumptions: the train's engine uses energy with
an efficiency of 0.90;
% the drag-area of the train is
$\cd A_{\rm train} = 11$\,m$^2$;
$m_{\rm train}=400\,000\,\kg$; and $C_{\rm{rr}}=0.002$.
} \label{fig.trainTheory8}
}
}
\end{center}
\end{myfloat}
%\section{Queries}
\subsection{What about rolling resistance?}
Some things we've completely ignored so far are
the energy consumed in the tyres and bearings of the car,
the energy that goes into the noise of wheels against
asphalt, the energy that goes into grinding
rubber off the tyres, and the energy that vehicles put into
shaking the ground.
Collectively, these forms of energy consumption
are called {\em\ind{rolling resistance}}. The standard model
of rolling resistance
asserts that the force of rolling resistance
is simply proportional to the weight of the vehicle,
independent of the speed.
The constant of proportionality is called the
coefficient of rolling resistance, $C_{\rm{rr}}$.
\Tabref{tab.Crr} gives some typical values.
The coefficient of rolling resistance for a car is about 0.01.
The effect of rolling resistance is just like perpetually
driving up a hill with a slope of one in a hundred.
% If set moving, a car will roll at steady speed
% down a hill with a slope of one in a hundred.
So rolling friction is about 100 newtons per \tonne, independent of
speed. You can confirm this by pushing a typical one-\tonne\ car
along a flat road. Once you've got it moving, you'll find you can
keep it moving with one hand. (100 newtons is the weight of 100
apples.)\index{newton}\index{apple}\index{weight}
So at a speed of
% 25\,m/s (55\,mph), the power required to overcome
31\,m/s (70\,mph), the power required to overcome
rolling resistance, for a one-\tonne\ vehicle, is
\[
% (\mbox{10\,Newtons}) \times (25\,\m/\s) = 250\,\W ;
\mbox{force} \times \mbox{velocity} \:=\:
(\mbox{100 newtons}) \times (31\,\m/\s) \:=\: 3100\,\W ;
\]
which, allowing for an engine efficiency of 25\%,
requires 12\,kW of power to go into the engine;
whereas the power required to overcome drag was estimated
on \pref{Poweris80}
% {pageDragCar}
to be 80\,\kW\@.
So, at high speed, about 15\% of the power is required for
rolling resistance.
\Figref{fig.carsTheory} shows the theory of
fuel consumption (energy per unit distance)
as a function of steady speed, when we add together the
air resistance and rolling resistance.
The speed at which a car's rolling resistance is equal to
its air resistance is
given by
\[
C_{\rm{rr}} m_{\rm c} g = \frac{1}{2} \rho \cd A v^2 ,
\]
that is,
\[
v = \sqrt{
2 \frac{C_{\rm{rr}} m_{\rm c} g}{ \rho \cd A }
} =
% corrected error feb 2010 !!!!!!!
% sqrt( 2 * 0.01 * 1e3 * 9.81 / 1.3 / 1.0 )
13\,\m/\s
= 29\,\mbox{miles per hour.}
\]
% or 16\,mph.
% At 32\,mph, one fifth of the power is required for
% rolling resistance. At 48\,mph, one tenth.
}% end troublesoem page hack
\subsubsection{Bicycles}
%For truly sustainable transport look to human powered vehicles (HPVs)
% this includes bicycles with the aid of a trailer
% http://www.bikesandtrailers.com/bike-trailers/index.html for example
% or with a load carrying wheelbase extension
% http://www.xtracycle.com/html/home.php. If you must ride in all
% weathers then you may either use good quality waterproof clothing or
% a velomobile eg http://www.letra.dk ,http://www.velomobiel.nl or
% http://www.cab-bike.com to name but a few.
%% from http://www.bbc.co.uk/dna/actionnetwork/A3651932
%% Alexander Rice
For a bicycle ($m=90\,\kg$, $A=0.75\,\m^2$),
% the speed above which rolling resistance is less than air resistance is
%\[
% v =
%% sqrt( 2 * 0.005 * 90 * 9.81 / 1.3 / 0.75 )
% 3\,\m/\s
%\]
% or 7\,mph.
%% 6.71
the transition%
\amarginfig{b}{\footnotesize
\begin{center}
\mbox{\rotatebox{90}{\footnotesize\sf Energy consumption (kWh/100 km)}\hspace*{8mm}%
{\epsfxsize=40mm\epsfbox{../data/cars.eps}}%
}\\[0.2in]
{\sf{speed (km/h)}}
\\
\end{center}
% COLON
\caption[a]{Current cars' fuel consumptions
do not vary as speed squared.
% Vertical axis: Energy consumption in kWh per 100\,km.
% Horizontal axis: Speed in km/h.
Prius data from B.Z.\ Wilson;
BMW data from Phil C.\ Stuart.
% The Prius figures are from three separate experiments
%
% with slightly different conditions, but in all
% cases the car moved at constant speed under cruise control.
The smooth curve shows what a speed-squared curve would look like,
assuming a drag-area of 0.6\,m$^2$.
}
\label{fig.cars0}
% this figure deliberately placed early *** (check whether it can go later)
}
from rolling-res\-ist\-ance-dom\-in\-ated
cycling to air-resistance-dominated cycling takes place
at a speed of about 12\,km/h.
At a steady speed of 20\,km/h,
cycling costs about \eccol{2.2\,kWh per 100\,km}.
By adopting an aerodynamic posture, you can reduce your
drag area and cut the energy consumption down to
about 1.6\,kWh per 100\,km.
% Electric bicycle (according to a friendly user):
% uses 1\,kWh(e) per 100\,km.
% (I think he pedals too.)
% For a bike, {\em \ldots move bike here?}
\subsubsection{Trains}
For an eight-carriage
% high-speed
train as depicted in \figref{fig.stoptrain}
($m=400\,000\,\kg$, $A=11\,\m^2$), the speed
above which\index{cartoon!train}\index{rail}\index{train}
air resistance
is greater than rolling resistance
is
\[
v =
% sqrt( 2 * 0.002 * 400000 * 9.81 / 1.3 / 11.0 )
33\,\m/\s = 74\,\mbox{miles per hour}.
\]
% or 74\,mph.
For a single-carriage
train ($m=50\,000\,\kg$, $A=11\,\m^2$) , the speed
above which
air resistance
is greater than rolling resistance
is
\[
v =
% sqrt( 2 * 0.002 * 50000 * 9.81 / 1.3 / 11.0 )
12\,\m/\s = 26\,\mbox{miles per hour}.
\]
% or 26\,mph.
\subsection{Dependence of power on speed}
When I say that halving your driving speed should reduce
fuel consumption (in miles per gallon) to {\em one quarter\/} of current levels,
some people feel sceptical. They have a point: most cars'
engines have an optimum revolution rate,
\amarginfig{b}{
\begin{center}
\mbox{\epsfxsize=43mm%
\mono{\epsfbox{../data/mono/EnginePower.eps}}%
{\epsfbox{../data/EnginePower.eps}}%
}%
% \\[0.16in]
\end{center}
\caption[a]{Powers of cars (kW) versus their top speeds (km/h).
Both scales are logarithmic.
The power increases as the third power of the speed.
To go twice as fast requires eight times as much engine power.
From \protect\cite{flight}.}
\label{fig.cars}
}%
and the choice of gears of the car determines a range
of speeds at which the optimum engine efficiency can be delivered.
If my suggested experiment of halving the car's speed takes the car out
of this designed range of speeds, the consumption might not fall by
as much as four-fold.
My tacit assumption that the engine's efficiency is the
same at all speeds and all loads led to the conclusion that it's
always good (in terms of miles per gallon) to travel slower;
but if the engine's efficiency drops off at low speeds, then
the most fuel-efficient speed might be at an intermediate speed that
makes a compromise between going slow and keeping the engine efficient.
For the BMW\,318ti in \index{BMW}\figref{fig.cars0}, for example, the optimum
speed is about 60\,km/h.
But if society were to decide that car speeds should be reduced,
there is nothing to stop engines and gears being redesigned
so that the peak engine efficiency was found at the right speed.
As further evidence that the power a car requires
really does increase as the cube of speed, \figref{fig.cars} shows the
engine power versus the top speeds of a range of cars. The line shows
the relationship ``power proportional to $v^3$.''
\subsection{Electric cars: is range a problem?}
\label{ch.cars2Range}
\index{electric car!range}People
often say that the range of electric cars is not big enough.
Electric car advocates say ``no problem, we can just put in more batteries'' --
and that's true, but we need to work out what effect the extra batteries
have on the energy consumption.
The answer depends sensitively on
what energy density we assume the batteries deliver:
for an energy density of 40\,Wh/kg (typical
of lead-acid batteries), we'll see that
it's hard to push the range
beyond 200 or 300\,km; but for an energy density
of 120\,Wh/kg (typical of various lithium-based
batteries), a range of 500\,km is easily achievable.
\amarginfig{b}{
\begin{center}
\mbox{\epsfxsize=53mm%
{\epsfbox{../data/carselec.eps}}%
}%\\[0.1in]
\end{center}
\caption[a]{Theory of electric car range (horizontal
axis) and transport cost (vertical axis) as a function
of battery mass, for two battery technologies.\index{electric car!theory}
A car with 500\,kg of
old batteries, with an energy density of 40\,Wh per kg,
has a range of 180\,km.
With the same weight of
modern batteries, delivering 120\,Wh per kg,
an electric car can have a range of more than 500\,km.
Both cars would have an energy cost of about 13\,kWh per 100\,km.
These numbers allow for a
battery charging efficiency of 85\%.
}
\label{fig.carselec}
}
% So, let's work out what our cartoon says about the range of an electric car.
Let's assume that the mass of the car and occupants\index{electric car!theory}
is 740\,kg, {\em without\/} any batteries.\index{range!electric car}
In due course we'll add 100\,kg, 200\,kg, 500\,kg, or
perhaps 1000\,kg of batteries.\index{electric car!range}
Let's assume a typical speed of 50\,km/h (30\,mph);
a drag-area of 0.8\,m$^2$; a rolling resistance of 0.01;
a distance between stops of 500\,m; an engine efficiency of 85\%;
and that
during stops and starts, regenerative braking recovers half
of the kinetic energy of the car.
Charging up the car from the mains is assumed to be 85\% efficient.
\Figref{fig.carselec} shows the transport cost of the
car versus its range, as we vary the amount of
battery on board.
The upper curve shows the result for a battery whose energy density
is 40\,Wh/kg (old-style lead-acid batteries).
The range is limited by a wall at about
500\,km. To get close to this maximum range, we
have to take along comically large batteries:
for a range of 400\,km, for example, 2000\,kg of
batteries are required, and the transport cost is above 25\,kWh per 100\,km.
If we are content with a range of
180\,km, however, we can get by with 500\,kg of batteries.
Things get much better when we switch to lighter lithium-ion batteries.
At an energy density of 120\,Wh/kg, electric cars with 500\,kg
of batteries can easily deliver a range of 500\,km.
The transport cost is predicted to be about 13\,kWh per 100\,km.
It thus seems to me that the range problem\index{electric car!range}
has been solved by the advent of modern batteries.
It would be nice to have even better batteries, but
an energy density of 120\,Wh per kg is already
good enough, as long as we're happy for the
batteries in a car to weigh up to 500\,kg.\index{battery!energy density}
In practice I imagine most people would be
content to have a range of 300\,km, which can be
delivered by 250\,kg of batteries. If these batteries
were divided into ten 25\,kg chunks, separately
unpluggable, then a car user could keep just
four of the ten chunks on board when he's doing regular
commuting (100\,kg gives a range of 140\,km);
and collect an extra six chunks from a\index{car!recharging}
battery-recharging station when he wants to
make longer-range trips. During long-range trips, he would
exchange his batteries for a fresh set\index{electric car!recharging}\index{recharging}
at a \index{battery exchange}%
battery-exchange station\index{filling station!role in electric transport}
every 300\,km or so.
% BP would be responsible for recharging the batteries
\small
\section*{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pCarEng25}]
{\nqs{
Typical petrol engines are about 25\% efficient}.
}
Encarta \tinyurl{6by8x}{http://encarta.msn.com/encyclopedia_761553622/Internal-Combustion_Engine.html}
says ``The efficiencies of good modern Otto-cycle engines range between 20 and 25\%.''
% This rough statistic is backed up by this webpage
% \myurl{http://www.fueleconomy.gov/feg/atv.shtml},
% 17\% of the energy idle
% 62.4 engine losses
% 18.2 comes out of the engine and goes somewhere.
% 2.2 to other things
% which shows that engine losses
% are three times the power going to the driveline
% and other accessories.
% Wikipedia
% http://en.wikipedia.org/wiki/Internal_combustion_engine#Engine_Efficiency
% says ``as high as 37\% at the optimum operating point'' but
% normally about 20\%, because car engines are usually not at their
% sweet spot, sadly.
% I wonder if they are using net or gross 5% difference!
The petrol engine
of a Toyota Prius, famously one of the most efficient
car engines, uses the Atkinson cycle instead of the
Otto cycle; it has a peak power output of 52\,kW
% 70 hp
and has an efficiency of 34\%
when delivering 10\,kW
\tinyurl{348whs}{http://www.cleangreencar.co.nz/page/prius-petrol-engine}.
% Octane engines reach 32\%
% http://ecen.com/content/eee7/motoref.htm
%
%
% From Toyota:
% http://www.cleangreencar.co.nz/page/toyota-prius-iii-hybrid-car-technical-information
% prius electric motor 1 is 18 kW
% Motore 2 maximum power of 33 kW in the Generation II Prius and 50 kW in the Generation III Prius.
% The Generation II Prius high-voltage battery pack consists of 228 cells of 1.2 volts each for a total nominal voltage of 273.6 volts. The cells are arranged in 38 modules of 6 cells each and the whole lot is assembled into a unit that is fixed behind the rear seat. You can see where it is from the bump at the bottom rear of the boot. The maximum current of the battery is 80 amps discharge and 50 amps charge. This is remarkable, since each cell is similar in size to an ordinary D-cell such as you would use in a large flashlight.
% Maximum efficiency generally occurs at around half of the engine's peak power output.
% Battery capacity is 1.5kWh - delivers 1.35kWh?
%
The most efficient diesel engine in the world is
52\%-efficient, but it's not suitable for cars
as it weighs 2300 \tonnes:
the \ind{Wartsila--Sulzer} RTA96-C turbocharged diesel
engine (\figref{Wart}) is intended for container ships and has a power output of 80\,MW\@.
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/wartsila400.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/wartsila800.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{The Wartsila-Sulzer RTA96-C 14-cylinder two-stroke diesel engine.
27\,m long and 13.5\,m high.
\myurlb{www.wartsila.com}{http://www.wartsila.com/}
}\label{Wart}
}
% image from http://www.wartsila.com/ press release site (youfigure.mgp)
% the most powerful and most efficient diesel engine - Japan's Diesel United
\item[\npageref{pRegenEff}]
{\nqs{Regenerative brakes roughly
halve the energy lost in braking}.}
Source: \cite{E4tech}.
%The e4 document in refs/transport says current hybrids recover about half the braking energy.
\item[\npageref{pElecEnginPowRat}]
{\nqs{Electric engines can be about 8 times lighter than petrol engines}.}
% {\bf Engine power:}
\par
% this par added to prevent an ORB
A 4-stroke petrol engine has a power-to-mass ratio of
% aero-engine power rating delivers
% ~ 1HP/kg =
roughly 0.75\,kW$\!$/kg.
The best electric motors have an efficiency of 90\% and a power-to-mass ratio of 6\,kW$\!$/kg.
So replacing a 75\,kW petrol engine with a 75\,kW electric motor saves 85\,kg in weight.
% , but this
% corresponds to only 13\,kWh of battery capacity = 4\,kg of petrol
Sadly, the power to weight ratio of batteries is about 1\,kW per kg, so
what the electric vehicle gained on the motor, it loses on the batteries.
\item[\npageref{pBikeCrr}]
{\nqs{The bike's engine
uses energy with an efficiency of 0.25}.}
This and the other assumptions about cycling
are confirmed by \citet{Prampero}.
The drag-area of a cyclist in racing posture is
% cf the 0.75 that I assumed
$\cd A = 0.3\,\m^2$. The rolling resistance of
a cyclist on a high-quality
racing cycle (total weight 73\,kg) is 3.2\,N.\label{bikeref}
% \cite{Prampero}
% (Di Prampero et al 1979).
% from Alan Cummings ``Cycling in the Wind''
% J Appl Physiology Prampero
% (1.6 kWh) per (100 km) = 57.6 newtons
\item[\npageref{fig.cars0}] {\nqs{\Figref{fig.cars0}.}}
Prius data from B.\ Z.\ Wilson
[\myurlb{home.hiwaay.net/ ~bzwilson/prius/}{http://home.hiwaay.net/ ~bzwilson/prius/}].
BMW data from Phil C.\ Stuart
[\myurlb{www.randomuseless.info/318ti/economy.html}{http://www.randomuseless.info/318ti/economy.html}].
\item[Further reading:]
\cite{WhatPriceSpeed}.
\end{notelist}
\normalsize
\gset\chapter{\gcol{Wind II}}
\label{ch.wind2}
\amarginfignocaption{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm\epsfbox{../../images/SimpleTurbineD.jpg.eps}} \\
\end{tabular}
\end{center}
% \caption[a]{ }
}
\section{The physics of wind power}
To estimate the energy in wind, let's imagine holding up
a hoop with area $A$, facing the wind
whose speed is $v$. Consider
the mass of air that passes through that hoop in one second.
Here's a picture of that mass of air just before it passes through the
\ind{hoop}:
\medskip\\
\begin{center}
{\mbox{\epsfbox{crosspad/newwind.1}}}
\medskip\\
\end{center}
\noindent
And here's a picture of the same mass of air one second later:
\medskip\\
\begin{center}
{\mbox{\epsfbox{crosspad/newwind.3}}}
\medskip\\
\end{center}
\noindent
The mass of this piece of air is the product of
its \ind{density} $\rho$, its area $A$, and its length, which is $v$ times $t$,
where $t$ is one second.%
\marginpar{
\fbox{\small
\begin{minipage}{50mm}
I'm using this formula again:
\[
\mbox{mass} = \mbox{density} \times \mbox{volume}
\]
\end{minipage}
}
\label{miniformulaGain}
}
\medskip\\
\begin{center}
{\mbox{\epsfbox{crosspad/newwind.2}}}
\medskip\\
\end{center}
\noindent
The \ind{kinetic energy} of this piece of air\index{cartoon!wind power} is
\beq
\frac{1}{2} m v^2 = \frac{1}{2} \rho A v t \, v^2 = \frac{1}{2} \rho A t v^3 .
\label{eq.windpower1}
\eeq
So the power of the wind, for an area $A$ -- that is, the kinetic
energy passing across that area per unit time -- is
\beq
\frac{ \frac{1}{2} m v^2}{t}
= \frac{1}{2} \rho A v^3 .
\label{eq.windpower}
\eeq
This formula may look familiar -- we derived an identical expression
on \pref{pageAvcubed} when we were discussing the power\index{power density!wind}
requirement of a moving car.
What's a typical wind speed? On a windy day, a cyclist really notices
the wind direction; if the wind is behind you,
\amarginfig{b}{\small
\begin{center}
\begin{tabular}{cccc} \toprule
miles/ & km/h & m/s & Beaufort \\
hour & & & scale \\ \midrule
% & 1 & 0.28 & \\
% 1 & 1.6 & & \\
2.2 & 3.6 & 1 & force 1 \\
7 & 11 &3 & force 2 \\
11 & 18 &5 & force 3 \\
13 & 21 &6 & \\
16 & 25 &7 & \raisebox{7pt}[0in]{force 4} \\
22 & 36 &10 & force 5 \\
29 & 47 &13 & force 6 \\
36 & 58 &16 & force 7 \\ % error: was 31!
%%
% [The definition of a moderate breeze (Beaufort force 4)
% is 13--18 miles per hour. A gale (force 8) is 39--46 miles per hour.]
% in met office records a day of gale is a day on which
% speed at 10m (averaged over 10 mins) was
% 34 knots / 39mph / 17.2m/s or more
% 15 & 24 & & Force 4 \\
% 20
%(19-24)
% & & 10 & 5 \\
% 25--31 & & 14 & 6 \\
% 32--38 & & 18 & 7 \\
%% & & & {\small{(moderate breeze)}} \\
%% 39-46
42 & 68 & 19 & force 8 \\
%% & & & {\small{(gale)}} \\
% & 100 & 28 & \\
% 70 & 110 & 31 & \\
% miles/ & km/h & m/s & Beaufort \\
% hour & & & scale \\ \midrule
49 & 79 & 22 & force 9\\
% 27 &97.2 &52.5 &60.4 &Force 10\\% Force 10
% 31 &111.6 &60.3 &69.3 &Force 11\\% Force 11
% 35 &126.0 &68.0 &78.3 &Force 12\\% Force 12
60 & 97 & 27 & force 10 \\
69 & 112 & 31 & force 11 \\
78 & 126 & 35 & force 12 \\
\bottomrule
\end{tabular}
\end{center}
\caption[a]{Speeds.
% 7 knots = 8\,mph = 13\,km/h = 3.6\,m/s.
\index{Beaufort scale}%
\index{speed}\index{conversion table, speed}\index{units!speed}
% A moderate breeze (Beaufort force 4)
% is 13--18 miles per hour. A gale (force 8) is 39--46 miles per hour
% \tinyurl{yfgfe7}{http://www.answers.com/topic/beaufort-scale}.
}
}%
% (You might enjoy noticing how similar this is
% to the formula for the power required by a high-speed car,
% on \pref{pageAvcubed}.)
you can go much faster than
normal;\index{cyclist}\index{estimation}\index{bicycle}
the speed of such a wind is therefore
comparable to the typical
speed of the cyclist, which is, let's say, 21\,\km\ per hour (13 miles per hour, or
6 metres per second). In Cambridge, the wind is only occasionally this big.
Nevertheless, let's use this as a typical British figure (and bear in mind that we may need
to revise our estimates).
%% In Europe, the wind is only rarely this big.
%% today's forecast: 10mph, tomorrow 21mph, then 12, 16, 23 (november gales)
%% http://www.answers.com/topic/beaufort-scale
The density of air
%% ykf4j9
%% http://hypertextbook.com/facts/2000/RachelChu.shtml
is about 1.3\,\kg\ per $\m^3$.
% \tinyurl{ykf4j9}{http://hypertextbook.com/facts/2000/RachelChu.shtml}.
(I usually round this to 1\,\kg\ per $\m^3$,
which is easier to remember, although
I haven't done so here.)
Then the typical power of the wind per square metre of hoop is
\beq
\frac{1}{2} \rho v^3 = \frac{1}{2} 1.3\,\kg/ \m^3 \times (6 \,\m/\s)^3
= 140 \,\Wmm .
\label{eq.windpower2}
\eeq
Not all of this energy can be extracted by a windmill. The windmill
slows the air down quite a lot, but it has to leave the air with {\em{some}\/}
kinetic energy, otherwise that slowed-down air would get in the way.
\Figref{fig.flowair} is
a cartoon of the actual flow past a windmill.
\begin{figure}[tbp]
\figuremargin{
\begin{center}
{\mbox{\epsfbox{crosspad/newwind.4}}}
%{\mbox{\epsfbox{crosspad/wind4.ps}}}
\end{center}
}{
\caption[a]{Flow of air past a windmill.\index{cartoon!windmill}
The air is slowed down and splayed out by the windmill. }
\label{fig.flowair}
}
\end{figure}
The maximum fraction of the incoming energy that can be extracted
by a disc-like windmill was worked out by a German physicist
called Albert \index{Betz, Albert}{Betz}\nlabel{betz} in 1919.
If the departing wind speed is one third of the arriving wind speed,
the power extracted is 16/27 of the total power in the wind.
16/27 is 0.59.
% Real windmills are not optimized to maximize this fraction, however
In practice let's guess that a windmill might be 50\% efficient.
In fact, real windmills are designed with particular
wind speeds in mind; if the wind speed is significantly greater than
the turbine's ideal speed, it has to be switched off.
As an example, let's assume a diameter of $d=25\,\m$, and a hub height of $32\,\m$,
which is roughly the
size of the lone windmill above the city of \ind{Wellington}, \ind{New Zealand}
(\figref{fig.wellingtonB}).
%% http://www.khantazi.org/Events/WindMill/WindMill.html
%% from the photo I think it is 32m high and has 24m diameter.
The power of a single windmill is
\beqan
& & \mbox{efficiency factor} \times \mbox{power per unit area} \times
\mbox{area} \nonumber \\
&=& 50\% \times \frac{1}{2} \rho v^3 \times \frac{\pi}{4} d^2
\label{eq.windpower3}
\\
&=& 50\% \times 140 \,{\Wmm} \times \frac{{\ensuremath{\pi}}}{4} (25\,\m)^2
% \times 25\,\m
\\
&=& 34\,\kW.
\eeqan
Indeed, when I visited this windmill on a very breezy day,
its meter showed it was generating 60\,\kW\@.
To estimate how much power we can get
% per person
from wind, we need to decide
how big our windmills are going to be, and how close together
we can pack them.
% How the figures work out will depend
% strongly on our assumptions about population density,
% a topic to which we will return in another chapter.
\marginfig{
%\begin{figure}
%\figuremargin{
\begin{center}
\mbox{\epsfxsize=53mm\epsfbox{../../images/windmill.ps}}
\end{center}
% }{
\caption[a]{The
\ind{Brooklyn windmill} above \ind{Wellington}, \ind{New Zealand},
% Brooklyn windmill above Wellington, N.Z.,
with people providing a scale at the base.
On a breezy day, this windmill was producing 60\,kW,
(1400\,kWh per day).
Photo by {Philip Banks}.}
\label{fig.wellingtonB}
}
%\end{figure}
% For the moment, let's take the population density of
% England: 380 people per square kilometre.
% The taller a windmill is, the bigger the wind speed it encounters.
How densely could such windmills be packed?
Too close and the upwind ones will cast wind-shadows on the downwind
ones.
Experts say that windmills can't be spaced closer than
5 times their diameter without losing significant power.
%\begin{figure}\figuremargin{
\marginfig{
\begin{center}
{\mbox{\epsfbox{metapost/wind2.55}}}
%{\mbox{\epsfbox{crosspad/wind5a.ps}}}
\end{center}
% }{
\caption[a]{{\Windfarm} layout.}
}%
% \end{figure}
At this spacing, the power that windmills can generate per unit land area is
\beqan
\frac{ \mbox{power per windmill (\ref{eq.windpower3})}}
{ \mbox{land area per windmill} }
& =& \frac{ \frac{1}{2} \rho v^3 \frac{\pi}{8} d^2 }
{ (5 d)^2 }
\label{eq.windpower4}
\\
& = & \frac{\pi}{200} \frac{1}{2} \rho v^3
\label{eq.windpower5}
\\
& = & 0.016 \times 140 \,\Wmm \\
& = & 2.2 \,\Wmm .
\eeqan
This number is worth remembering:
a {\windfarm} with a wind speed of
6\,m/s produces a power of 2\,W per m$^2$ of land area.
Notice that our answer does not depend on the diameter of the windmill.
The $d$s cancelled because bigger windmills have to be spaced
further apart.
\margintab{
% \begin{figure}
\begin{center}
\begin{tabular}{cc} \toprule
\multicolumn{2}{l}{\sc Power per unit area }\\ \midrule
{\windfarm} & 2\,\Wmm\\
(speed 6\,m/s) \\
\bottomrule
\end{tabular}
\end{center}
% }{
\caption[a]{Facts worth remembering: {\windfarm}s.
%% , number 1
}
}%
% \end{figure}
Bigger windmills might be a good idea in order to
catch bigger windspeeds that exist higher up (the taller a windmill is,
the bigger the wind speed it encounters),
or because of economies of scale, but
those are the only reasons for preferring big windmills.
This calculation depended sensitively on our estimate of
the windspeed.
Is 6\,m/s plausible as a long-term typical windspeed
in windy parts of Britain?
Figures \ref{fig.camb.wind}
and \ref{fig.cairngorm}
showed windspeeds in Cambridge and Cairngorm.
\Figref{Mawgan} shows the mean winter and summer
windspeeds in eight more locations around Britain.%
%\marginfig{
\begin{figure}[!bp]\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{\hspace*{-3mm}}c}
\mbox{\epsfbox{metapost/wind.2}}
&
\raisebox{47mm}{\epsfig{file=../../images/PUBLICDOMAIN/maps/wind.eps,angle=270}}
\\
\end{tabular}
\end{center}
}{
\caption[a]{Average summer windspeed (dark bar)
and average winter windspeed (light bar)\index{wind!data}\index{windspeed!data}
in eight locations around Britain.
Speeds were measured at the standard weatherman's height of
10 metres.
Averages are over the period 1971--2000.
}
\label{Mawgan}
}
\end{figure}
% (These are the windspeeds at the standard weatherman's height of
% 10\,\m; a)
%
I fear 6\,m/s was an overestimate of the typical speed
in most of Britain!
%% \,per\,second
If we replace 6\,m/s by Bedford's 4\,m/s as our estimated
windspeed, we must scale our estimate down,
multiplying it by $(4/6)^3 \simeq 0.3$.
(Remember, wind power scales as wind-speed cubed.)
%\beq
% \mbox{Maximum conceivable wind power (assuming 4\,\m/s)}
% = 40\,\kWh\,\mbox{per person per day}.
%\eeq
On the other hand, to estimate the typical power, we shouldn't take the
mean wind speed and cube it; rather, we should find the mean cube of the windspeed.
The average of the cube is bigger than the cube of the average.
But if we start getting into these details, things get even more complicated,
because real wind turbines don't actually deliver a power proportional to wind-speed cubed.
Rather, they typically have just a range of wind-speeds within which they deliver the ideal
power;
at higher or lower speeds real wind turbines deliver less than
the ideal power.
\subsection{Variation of wind speed with height}
Taller windmills see higher wind speeds.
The way that wind speed increases with height
is complicated and depends on the roughness of the
surrounding terrain and on the time of day.
As a ballpark figure, doubling the height
typically increases wind-speed by 10\%
and thus increases the power of the wind by 30\%.
Some standard formulae for speed $v$ as
a function of height $z$ are:
\begin{enumerate}
\item According to the wind shear formula from
NREL {\tinyurl{ydt7uk}{http://www.nrel.gov/business_opportunities/pdfs/31235sow.pdf}}%
%(Oct 2001)
%NREL
, the speed varies as a power of the height:
\[
v(z) = v_{10} \left( \frac{z}{10\,\m} \right)^{\alpha} ,
\]
\amarginfig{c}{\small
\begin{center}
Wind speed versus height\\[0.05in]
\mbox{\ \ \ \epsfxsize=45mm\epsfbox{figs/vversush.eps}} \\[0.2916in]
Power density of wind v.\ height\\[0.05in]
\mbox{\ \ \ \epsfxsize=45mm\epsfbox{figs/powerd.eps}} \\[0.16in]
\end{center}
\label{fig.WindZTheory}
% COLON
\caption[a]{
Top: Two models of wind speed and wind power as a function of
height.
DWIA = Danish Wind Industry Association;
NREL = National Renewable Energy Laboratory.
For each model the speed at 10\,m has been fixed to 6\,m/s.
For the Danish Wind model, the roughness length is set to
$z_0=0.1$\,m.
Bottom: The power density (the power per unit of upright area) according
to each of these models.
}
}%
where $v_{10}$ is the speed at 10\,m,
and a typical value of the exponent $\alpha$ is 0.143 or $1/7$.
% Thus
%\[
% v(z) \propto z^{1/7} .
%\]
The one-seventh law ($v(z)$ is proportional to $z^{1/7}$)
is used by \citet{ElliottWindy}, for example.
\item
The wind shear formula from the Danish Wind Industry Association
\tinyurl{yaoonz}{http://www.windpower.org/en/tour/wres/shear.htm}
is
\[
v(z) = v_{\rref} \frac{ \log ( z/z_0 ) }{ \log ( z_{\rref} / z_0 ) },
\]
where $z_0$ is a parameter called the roughness length, and $v_{\rref}$
is the speed at a reference height $z_{\rref}$ such as 10\,m.
The roughness length for typical countryside
(agricultural land with
some houses and sheltering hedgerows with some 500-m intervals -- ``roughness class 2'')
is $z_0 = 0.1\,\m$.
\end{enumerate}
In practice, these two wind shear formulae give
similar numerical answers.
That's not to say that they are accurate at all
times however. \citet{vdBerg2004} suggests that different
wind profiles often hold at night.
\subsection{Standard windmill properties}
The typical \ind{windmill} of
today has a \ind{rotor} diameter of around 54 metres
centred at a height of 80 metres; such a machine has
a ``capacity'' of 1\,MW\@. The ``\ind{capacity}'' or ``\ind{peak} power''
is the {\em maximum\/} power
the windmill can generate in optimal conditions.
\begin{figure}[tbp]
\figuredangle{
{\epsfxsize=153mm\epsfbox{../../images/qr6kW.eps}}%
}{
\caption[a]{The qr5 from \myurl{quietrevolution.co.uk}. Not a typical windmill.}
}
\end{figure}
Usually, wind turbines are designed to start running at wind
speeds somewhere around 3 to 5\,m/s
and to stop if the wind speed reaches gale speeds of
25\,m/s.\label{pWindFacts}
% \tinyurl{ymfbsn}{http://www.windpower.org/en/tour/wres/powdensi.htm}.
%% http://www.windpower.org/en/tour/wres/powdensi.htm
The actual average power delivered is the ``capacity'' multiplied
by a factor that describes the fraction of the time that wind conditions
are near optimal. This factor, sometimes called the ``\ind{load factor}''
or ``\ind{capacity factor},''
depends on the site; a typical load
factor for a {\em{good}\/} site in the UK is $30\%$.\nlabel{pCapFac}
In the
Netherlands, the typical load factor is 22\%;
in Germany, it is 19\%.
% Source: page 28 of the dutch wind doc
\subsection{Other people's estimates of {\windfarm} power per unit area}
In the government's study [\myurlb{www.world-nuclear.org/policy/DTI-PIU.pdf}{http://www.world-nuclear.org/policy/DTI-PIU.pdf}]
the \UK\ onshore wind resource is estimated
using an assumed {\windfarm} power per unit area of
at most
% 9\,MW/km$^2$, which is
9\,\Wmm\ (capacity, not average production).
% Include a typical capacity factor here to deduce the average {\windfarm}
% power density.
If the capacity factor is 33\% then the average power
production would be 3\,\Wmm.
% , which is just 50\% different from our 2\,W/m$^2$ estimate.
% whiteless
% 129 MW, aka 200,000 homes
% corresponds to 0.644 kW per home. or 15.5kWh/day PER HOME
% Humph, what is actual per person electricity consumption?
% Elec = 380 TWh/y for UK (TOTAL, not domestic)
% which is 17 kWh/day each.
% How many people in a home, and what fraction is domestic?
% I guess 3 people per home, and 50% domestic, so
% we need 3*17 / 2 per home. Yep, I think they are mis-estimating
% what a ``home'' really is.
The London Array
is an offshore {\windfarm} planned for the outer Thames Estuary. With its 1\,GW
capacity, it is expected to become the world's largest offshore {\windfarm}.
% The site is seven miles off the North Foreland on the Kent coast in the area of Long Sand and Kentish Knock [2]. It will cover 90 square miles between Margate in Kent and Clacton in Essex.
The completed {\windfarm} will consist of 271 wind turbines in
245\,km$^2$
\tinyurl{6o86ec}{http://www.londonarray.com/london-array-project-introduction/offshore/}
%% 90 square miles,
and will deliver
an average power of 3100\,GWh per year (350\,MW). (Cost \pounds 1.5\,bn.)
That's a power per unit area of 350\,MW/245\,km$^2$ = 1.4\,\Wmm.
This is lower than other offshore farms because, I guess,
the site includes a big channel (Knock Deep) that's too deep (about 20\,m)
for economical planting of turbines.
\myquote{%
I'm more worried about what these plans [for
% an electricity substation for
the proposed London Array {\windfarm}]
will do to this landscape and our way of life than I ever was about a
\ind{Nazi invasion} on the beach.\nlabel{pNazi}
}{
Bill Boggia
% , whose family owns and runs several caravan parks around
of Graveney,
where the undersea cables \\ \hfill of the \windfarm\ will come ashore.
%% http://news.independent.co.uk/environment/article2086678.ece
}
%\end{quote}
\section{Queries}
\beforeqa
\qa{What about \ind{micro-generation}?
If you plop one of those \ind{mini-turbine}s on your roof, what
energy can you expect it to deliver?
}{
Assuming a windspeed of 6\,m/s, which, as I said before, is
{\em above\/}
the average for most parts of Britain; and assuming a diameter of 1\,m,
\amarginfig{c}{
%\begin{figure}
%\figuremargin{
% \begin{center}
\mbox{%
\epsfysize=41.53mm\epsfbox{../../images/Warw13C.eps}%
\,%
\epsfysize=41.53mm\epsfbox{../../images/Warw14.eps}%
}\par
% \end{center}
% }{
\caption[a]{An Ampair ``600\,W'' \ind{micro-turbine}.
The average power generated by this micro-turbine
in Leamington Spa is 0.037\,kWh per day (1.5\,W).
% 30th October 2007 to 9th May 2008
% Photos by {Robert MacKay}.}
}
\label{fig.warwickwind}
}%
the power delivered would be 50\,W\@.
%% pr 70*pi/4.0 * 24
That's 1.3\,kWh per day -- not very much.
And in reality,
in a typical urban location in England,
a micro-turbine delivers just 0.2\,kWh per day
-- see \pref{pmicrowind}.
Perhaps the worst windmills in the world are
a set in \ind{Tsukuba City}, \ind{Japan}, which actually
consume more power than they generate. Their installers were so
embarrassed by the stationary turbines that they imported power to make them
spin so that they looked like they were working!
\tinyurl{6bkvbn}{http://www.timesonline.co.uk/tol/news/world/asia/article687157.ece}
}
% WHAT FOR? ***
% See \citeasnoun{Faber}, p.\,63.
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{betz}] {\nqs{The
maximum fraction of the incoming energy that can be extracted
by a disc-like windmill\ldots}}%
\marginfig{
\begin{center}
\mbox{\epsfxsize=42mm\epsfbox{../../images/Iskra5kW.eps}}
\end{center}
% }{
\caption[a]{% AT5-1
A 5.5-m diameter Iskra 5\,kW turbine
[\myurlb{www.iskrawind.com}{http://www.iskrawind.com/}]
having its annual check-up.
This turbine, located in Hertfordshire (not the windiest of locations
in Britain), mounted at a height of 12\,m,
has an average output of
% 4000 kWh per year
11\,kWh per day.
A {\windfarm} of machines with this performance, one per
30\,m $\times$ 30\,m square, would have a power per unit area of
% 0.507
\pdcol{0.5\,\Wmm}.
}
\label{fig.Iskra}
}
There is a nice explanation
of this
on the Danish Wind Industry Association's
website.
\tinyurl{yekdaa}{http://www.windpower.org/en/stat/betzpro.htm}.
%% http://www.windpower.org/en/stat/betzpro.htm
\item[\npageref{pWindFacts}]
{\nqs{Usually, wind turbines are designed to start running at wind
speeds around 3 to 5\,m/s}}.
\tinyurl{ymfbsn}{http://www.windpower.org/en/tour/wres/powdensi.htm}.
%% http://www.windpower.org/en/tour/wres/powdensi.htm
\item[\npageref{pCapFac}] {\nqs{a typical
\index{capacity factor}\ind{load factor} for a {{good}} site is $30\%$}.}
In 2005, the average load factor of all major UK
{\windfarm}s was
28\%\
% 28.4\%\
\tinyurl{ypvbvd}{http://www.ref.org.uk/images/pdfs/UK_Wind_Phase_1_web.pdf}.
The load factor varied during the year, with a low of 17\%
in June and July.
The load factor for the best region in the country --
\ind{Caithness}, \ind{Orkney} and the \ind{Shetland}s -- was 33\%.
The load factors of the two \index{offshore wind!load factor}{offshore} {\windfarm}s operating in 2005
were 36\% for \ind{North Hoyle} (off North \ind{Wales})
and
29\% for \ind{Scroby Sands} (off \ind{Great Yarmouth}).
% http://www.clowd.org.uk/Downloads/clowdCarbonSavings.pdf
% is a good report on exaggerated claims for a bedford {\windfarm}
Average load factors in 2006 for ten regions
were:
Cornwall 25\%;
Mid-Wales 27\%;
Cambridgeshire and Norfolk 25\%;
Cumbria 25\%;
Durham 16\%;
Southern Scotland 28\%;
Orkney and Shetlands 35\%;
Northeast Scotland 26\%;
Northern Ireland 31\%;
offshore 29\%.
% Average of all: 27\%
\tinyurlb{wbd8o}{http://www.ref.org.uk/energydata.php}
\item[] \cite{WatsonEtAl}
say a minimum annual mean wind speed
% (AMWS)
of 7.0\,m/s is
currently thought to be necessary for commercial viability of
wind power. About 33\% of UK land area
has such speeds.
% The British Wind
%Energy Association estimates that the UK has 65\,252 km$^2$ of land area suitable for wind
%generation.
% At an average power density of 2\,\Wmm,
%% 2\,MW per km$^2$
% this area of {\windfarm}s would deliver 130\,GW, or 52\,kWh/d per person.
%% the report then reduces this number using constraints of network, visual impact, etc
\end{notelist}
\normalsize
\rset\chapter{\rcol{Planes II}}
\label{ch.air2}\label{ch.flight2}
%%\label{ch.air2}
\myquote{What we need to do is to look at how you make air travel more energy efficient, how you develop the new fuels that will allow us to burn less energy and emit less.}{Tony Blair}
%% http://www.metro.co.uk/news/article.html?in_article_id=32127&in_page_id=34
%% 9 Jan 2007
%%% _flight.tex has further notes
\myquote{Hoping for the best is not a policy, it is a delusion.}{Emily Armistead, \ind{Greenpeace}}
\marginfig{
%\begin{figure}
%\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/PUBLICDOMAIN/Arctic_ternsSmall.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/PUBLICDOMAIN/Arctic_terns.jpg.eps}}}\\
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/PUBLICDOMAIN/BartailedGodwitSmall.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/PUBLICDOMAIN/BartailedGodwit.jpg.eps}}}\\
\lowres%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/PUBLICDOMAIN/AirForceOneSmall.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/PUBLICDOMAIN/AirForceOne.jpg.eps}}}\\
\end{tabular}
\end{center}
\caption[a]{
Birds:\index{bird}
two Arctic terns, a bar-tailed godwit, and a Boeing \ind{747}.
}
}%
\noindent
What are the fundamental limits of travel by flying?
Does the physics of flight require an unavoidable
use of a certain amount of energy, per \tonne, per kilometre flown?
What's the maximum distance a 300-\tonne\ Boeing 747 can fly?
What about a 1-kg
bar-tailed godwit or a
100-gram Arctic tern?
Just as \chref{ch.car}, in which we estimated consumption by cars,
% invalid carriages,
was followed by \chref{ch.car2}, offering a model of where the energy
goes in cars,
% invalid carriages,
this chapter fills out \chref{ch.air},
discussing where the energy goes in planes.
%%%% This discussion may interest you, because
% You'll be able to answer the question
% `if I take 30\,\kg\ less luggage with me on my trip,
% does that make any difference to the energy consumed by the
% plane?'
The only physics required
% you'll need to understand this
is \ind{Newton's laws}\index{physics!Newton's laws}
of motion, which I'll describe when they're needed.
This discussion will allow us to answer questions such as
``would air travel consume much less energy if
we travelled in slower propellor-driven planes?''\index{myth!planes should fly slower}
There's a lot of equations ahead: I hope you enjoy them!\index{flight!myth about going slower}\index{plane!myth about flying slower}
% But if not, feel free to skip to the next chapter (\pref{chsolar}).
\section{How to fly}
Planes (and birds) move through air, so, just like cars and trains,
they experience a drag force, and much of the energy
guzzled by a plane goes into pushing the plane along
against this force.\index{bird!theory of} Additionally, unlike cars and trains,
planes have to
expend energy {\em{in order to stay up}}.
Planes stay up by throwing air down.
When the plane pushes down on air, the air pushes up on
the plane (because Newton's third law tells it to).
As long as this upward
push, which is called lift,
is big enough to balance the downward weight of the plane, the plane
avoids plummeting downwards.
When the plane throws air down, it gives that air kinetic energy.
So creating lift requires energy.
The total power required by the plane is the sum of the
power required to create lift and the power required to
overcome ordinary drag. (The power required to create lift is usually
called ``induced drag,'' by the way. But I'll call it the lift power, $P_{\rm lift}$.)
% \marginpar{*** \ \ \ Warning \ \ \ ***}
% \marginpar{*** Equations ahead ***}
The two equations we'll need, in order to work out a theory of flight,
are Newton's second law:
\begin{equation}
\mbox{force} = \mbox{rate of change of momentum},
\end{equation}
and Newton's third law, which I just mentioned:
\begin{equation}
\mbox{force exerted on A by B} = -\,
\mbox{force exerted on B by A}.
\end{equation}
If you don't like equations, I can tell you the punchline now:
we're going to find that the power required to create lift turns out to be
{\em{equal}\/} to the power required to overcome drag.
So the requirement to ``stay up'' {\em{doubles}\/} the power required.
\begin{figure}
\figuremargin{
\begin{center}
\begin{tabular}{ll}
\makebox[0in][l]{\sf Before} &
{\mbox{\epsfbox{crosspad/plane2c.1}}} \\
\makebox[0in][l]{\sf After} &
\hspace*{1.01in}{\mbox{\epsfbox{crosspad/plane2c.2}}}\\
\end{tabular}
\end{center}
}{
\caption[a]{A plane encounters a stationary tube of air. Once the plane
has passed by, the air has been thrown downwards by the plane.
The force exerted by the plane on the air to accelerate it downwards is
equal and opposite to the upwards force
exerted on the plane by the air.
}
\label{fig.sausage}
}
\end{figure}
\begin{figure}
\figuremargin{\small
% mpost earth.mp ; tex wrapper ; dvips wrapper ; gv wrapper
\begin{center}
\begin{tabular}{cc}
\raisebox{3mm}{\mbox{\epsfbox{crosspad/plane3a.1}}} &
{\mbox{\epsfbox{crosspad/plane3a.2}}}\\
{\sf Cartoon} &
{\sf A little closer to reality} \\
\end{tabular}
\end{center}
}{
\caption[a]{Our cartoon assumes that
the plane leaves
a \ind{sausage} of air moving down in its wake.
% The diameter of the sausage is roughly equal to the wingspan
% of the plane.
% cross-sectional area $\As$ is r
A realistic picture involves a more complex
swirling flow. For the real thing, see \protect\figref{fig.planeflow}.
}
\label{fig.swirl}
}
\end{figure}
%\subsection{The physics of flight}
Let's make a cartoon of the lift force on
a plane moving at speed $v$.\index{cartoon!flight}
In a time $t$ the plane moves a distance $vt$ and leaves
behind it a sausage of downward-moving air (\figref{fig.sausage}).
We'll call the cross-sectional area of this sausage \As.
This sausage's diameter is roughly equal to the \ind{wing}span $w$
of the plane.
(Within this large sausage is a smaller sausage
of swirling turbulent air with cross-sectional area similar
to the frontal area of the plane's body.)
Actually, the details of the air flow are much more interesting
than this sausage picture: each wing tip leaves behind it a \ind{vortex},
with the air between the wingtips moving down fast, and the
air beyond (outside)
the wingtips moving up (figures \ref{fig.swirl} \& \ref{fig.planeflow}).
This upward-moving air is exploited
by birds flying in formation:
just behind the tip of a bird's wing is a sweet little
updraft.\index{bird!formation flying}\index{formation flying}\index{flight!formation}
Anyway, let's get back to our \ind{sausage}.
\marginfig{
\begin{center}
\begin{tabular}{c}
\lowres%
{\mbox{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/Airplane_vortex_tiny.jpg.eps}}}%
{\mbox{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/Airplane_vortex_small.jpg.eps}}} \\
\end{tabular}
\end{center}
\caption[a]{
Air flow behind a plane.
Photo by NASA Langley Research Center.
}\label{fig.planeflow}
}
The sausage's mass is
\beq
m_{\rm sausage} = \mbox{density} \times \mbox{volume}
= \rho vt \As.
\eeq
%
Let's say the whole sausage is moving down with speed $u$,
and figure out what $u$ needs to be in order for the plane
to experience a lift force equal to its weight $mg$.
The downward momentum of the sausage created in time $t$ is
\beq
\mbox{mass} \times
\mbox{velocity}
=
m_{\rm sausage} u = \rho vt \As u.
\eeq
And by Newton's laws this must equal the momentum
delivered by the plane's weight in time $t$, namely,
\beq
m g t.
\eeq
Rearranging this equation,
\beq
\rho vt \As u = m g t ,
\eeq
we can solve for the
required downward sausage speed,
\[
u = \frac{m g }{ \rho v \As } .
\]
Interesting! The sausage speed is {\em{inversely}\/} related
to the plane's speed $v$. A slow-moving plane has to throw
down air
% the air that it encounters
harder than a fast-moving plane,
because it encounters less air per unit time.
That's why landing planes, travelling slowly,
have to extend their flaps: so as to create a larger and steeper
wing that deflects air more.
What's the energetic cost of pushing the sausage down at the required speed $u$?
The power required is
\beqan
P_{\rm lift} &=& \frac{ \mbox{kinetic energy of sausage} }
{ \mbox{time} }
\\
&=& \frac{1}{t} \frac{1}{2} m_{\rm sausage} u^2 \\
&=& \frac{1}{2t} \rho vt \As \left( \frac{m g }{ \rho v \As } \right)^2
\\
&=&
\frac{1}{2} \frac{(mg)^2}{\rho v \As}
.
\eeqan
% Notice that this lift-related power scales as the weight of the
% plane {\em{squared}}.
The total power required to keep the plane going is the sum of
the drag power and the lift power:
% and the power required to overcome drag:
\beqan
P_{\rm total} &=& P_{\rm drag} + P_{\rm lift}\\
&=&
\frac{1}{2} c_{\rm d} \rho \Ap v^3
+ \frac{1}{2} \frac{(mg)^2}{\rho v \As}
,
\eeqan
where $\Ap$ is the frontal area of the plane and $c_{\rm d}$
is its drag coefficient (as in \chref{ch.cars2}).
The fuel-efficiency of the plane, expressed as the
energy per distance travelled, would be
\beq
\left. \frac{ \mbox{energy} }{ \mbox{distance} }\right|_{\rm ideal} =
\frac{ P_{\rm total} }{ v } =
\frac{1}{2} c_{\rm d} \rho \Ap v^2
+ \frac{1}{2} \frac{(mg)^2}{\rho v^2 \As}
,
\label{eq.forceplane}
\eeq
if the plane turned its fuel's power into drag power
and lift power perfectly efficiently. (Incidentally,
another name for ``energy per distance travelled'' is ``force,''
%
and we can recognize the two terms above as
the drag force $ \frac{1}{2} c_{\rm d} \rho \Ap v^2$
and the lift-related force
%% (also known as the induced drag)
% [CHECK]
$\frac{1}{2} \frac{(mg)^2}{\rho v^2 \As}$.
The sum is the force, or ``thrust,'' that specifies exactly
how hard the engines have to push.)
\amarginfig{t}{% produced by gnuplot < gnu.flight
\small \begin{center}
\sf thrust (kN) \hfill \,\hspace*{1cm} \\[1.5mm]
\mono%%% \raisebox{-2mm}{$v$}
{\epsfxsize=53mm\epsfbox{figs/flightv.eps}}%
{\epsfxsize=53mm\epsfbox{figs/flightvC.eps}}%
\\
\hfill speed (m/s)
\end{center}
\caption[a]{The force required to keep a plane moving,
as a function of its speed $v$,
is the sum of an ordinary
drag force $ \frac{1}{2} c_{\rm d} \rho \Ap v^2$ -- which increases
with speed --
and the lift-related force (also known as the induced drag)
$\frac{1}{2} \frac{(mg)^2}{\rho v^2 \As}$ -- which decreases
with speed.
There is an ideal speed, $v_{\rm optimal}$, at which the
force required is minimized. The force is an energy per distance,
so minimizing the force also minimizes the fuel per distance.
To optimize the
fuel efficiency, fly at $v_{\rm optimal}$.
This graph shows our cartoon's estimate of the
thrust required, in kilonewtons, for a
Boeing \ind{747}\nlabel{p747da} of mass 319\,t, wingspan 64.4\,m, drag coefficient 0.03,
and frontal area 180\,m$^2$, travelling
in air of density $\rho = 0.41\,$kg/m$^3$
% .4135
(the density at a height of 10\,km),
as a function of its speed $v$ in m/s.
Our model has an optimal speed $v_{\rm optimal} = 220\,\m/\s$ (540\,mph).
For a cartoon based on \ind{sausage}s, this is a good match to real life!}
\label{fig.forcesum}
}%
Real jet engines have an efficiency of about $\epsilon = 1/3$,\nlabel{peffEng}
so the energy-per-distance of a plane travelling at speed $v$ is
\beq
\frac{ \mbox{energy} }{ \mbox{distance} } =
\frac{1}{\epsilon} \left(
\frac{1}{2} c_{\rm d} \rho \Ap v^2
+ \frac{1}{2} \frac{(mg)^2}{\rho v^2 \As}
\right).
\eeq
This energy-per-distance is fairly complicated; but
it simplifies greatly if we assume that the plane is {\em{designed}\/}
to fly
at the speed that {\em{minimizes}\/} the energy-per-distance.
The energy-per-distance, you see,
has got a sweet-spot as a function of $v$ (figure \ref{fig.forcesum}).
The sum of the two quantities
$ \frac{1}{2} c_{\rm d} \rho \Ap v^2$ and
$ \frac{1}{2} \frac{(mg)^2}{\rho v^2 \As} $
is smallest when the two quantities are equal.
This phenomenon is delightfully common in physics and engineering:
two things that don't obviously {\em{have}\/} to be equal {\em{are}\/}
actually equal, or equal within a factor of 2.
% For example, in
% Newtonian mechanics,
% the average kinetic energy of a pendulum,
% and the average of its potential energy (relative to its energy
% when hanging vertically) are equal;
% in thermodynamics, the
% average kinetic energy of a molecule in the air is exactly
% half the average of its potential energy (relative to zero defined by
% the earth's surface); and
% another engineering example ....
So, this equality principle tells us that the optimum speed
for the plane is such that
\beq
c_{\rm d} \rho \Ap v^2 = \frac{(mg)^2}{\rho v^2 \As} ,
\eeq
\ie,
%\beq
% v_{\rm opt}^4 = \frac{(mg)^2}{\rho^2 \As c_{\rm d} \Ap } ,
%\eeq
\beq
\rho v_{\rm opt}^2 = \frac{mg}{ \sqrt{c_{\rm d} \Ap \As } } ,
\label{eq.optV}
\eeq
%\beq
% v_{\rm opt} = \left( \frac{(mg)^2}{\rho^2 \As c_{\rm d} \Ap }
%\right)^{1/4}.
%\eeq
%\beq
% v_{\rm opt} =
% \frac{(mg)^{1/2}}{\rho^{1/2} w^{1/2}
% ( c_{\rm d} \Ap )^{1/4} }.
%\eeq
This defines the optimum speed if our \ind{cartoon of flight} is accurate; the
cartoon breaks down if the engine efficiency $\epsilon$ depends
significantly on speed, or if the speed of the plane exceeds
the speed of sound (330\,m/s); above the speed of sound, we would need
a different model of drag and lift.
Let's check our model by seeing what it predicts is the
optimum speed for
a 747 and for an \ind{albatross}.
%% nonstop flight record march 23-24 Washington to Cape City??
%% 16560km. range
%% cabin width 6.1m, vertical height 10m
We must take care to use the correct air-density: if
we want to estimate the optimum cruising speed for a 747 at
$30\,000$ feet, we must remember that air density drops with
increasing \ind{altitude} $z$
as $\exp ( - m g z / kT )$, where $m$ is the mass of \ind{nitrogen} or \ind{oxygen}
molecules, and $kT$ is the thermal energy (\ind{Boltzmann}'s constant
times absolute temperature).
The density is about $3$ times smaller at that
altitude.%
%% I get exp(-1.007) when I use T=300, m=28 amu, g=9.81... factor of 2.737
%% but it varies with temperature...
%% The
\begin{table}
\figuremargin{
\begin{center}\begin{tabular}{lccc}\toprule
{\sc{Bird}} & & 747 & Albatross \\ \midrule
Designer & & Boeing & natural selection\\
% Mass &$m$ & 181,000\,\kg & 8\,\kg \\ % without fuel
% 170,000 without fuel
% Fuel volume 240,000\,\litre
% Fuel mass 240,000\,\litre * 0.7 kg/l = 168\,000 kg
% passenger: 80kg. luggage: 40. food containers, water, drinks? 10 kg each?
% Mass of passengers and luggage 416 * ( 80 + 40 +10) = 54080
%% * For a typical international flight, one 747 operator uses about 5.5 tons (5,000 kg) of food supplies and more than 50,000 in-flight service items.
%% http://www.boeing.com/commercial/747family/pf/pf_facts.html
%%
Mass (fully-laden) &$m$ & 363\,000\,\kg & 8\,\kg \\
%% including fuel
%%% from www.boeing.com/
% % http://www.boeing.com/commercial/747family/pf/pf_classics.html
%%% max takeoff weight for a 747-100 was 333400kg. fuel capacity 183380l , range 9,800km. (452 passengers max)
%%% TYPICAL cruise speed = mach 0.84 = 555mph = 895 km/h
%%% max takeoff weight for a 747-200 was 374850kg. fuel capacity 199000l , range 12,700km. (452 passengers max)
%%% TYPICAL cruise speed = mach 0.84 = 555mph = 895 km/h
%%% max takeoff weight for a 747-300 was 374850kg. fuel capacity 199000l , range 12,400km. (496 passengers max)
%%% TYPICAL cruise speed = mach 0.85 = 565mph = 910 km/h
%%% http://www.boeing.com/commercial/747family/pf/pf_400er_prod.html
%%% max takeoff weight for a 747-400ER was 412775kg. fuel capacity 241000l , range 14,200km. (524 passengers max, 416 also typical) (has 2 extra fuel tanks in a cargo hold)
%%% 416 seems to be the standard number
%%% TYPICAL cruise speed = mach 0.855 = 567mph = 912 km/h
%%
%%
%% according to narita airport site,
%% maximum takeof weights of 7474s are
%% 335000, and 322000, for two different 747s
%% I estimate Mass at takeoff is 403000
%% I think a reasonable est for the halfway mass is 319000.
%% pr 181000 + 0.5*168000 + 54080
Wingspan&$w$& 64.4\,\m & 3.3\,\m \\
Area$^\star$ &$\Ap$& 180\,$\m^2$ & $0.09\,\m^2$ \\
%% filling factor is 0.0434
Density&$\rho$& $0.4\,\kg/\m^3$ & $1.2\,\kg/\m^3$ \\
Drag coefficient & $c_{\rm d}$& 0.03 & 0.1 \\
\midrule
Optimum speed & $v_{\rm opt}$ & 220\,\m/\s & 14\,\m/\s \\
& & = 540\,\mph & = 32\,\mph \\
\bottomrule
\end{tabular}
\end{center}
}{
\caption[a]{Estimating the optimal speeds for a \ind{jumbo jet} and
an \ind{albatross}.
%% CHECK whether the mass includes passengers and cargo and fuel.
%% Find out the actual air density at 30000 feet and recompute.
% http://www.pdas.com/m1.htm
%% see pdas.tex
% Density at 10km height is 0.4135 kg/m$^3$
% v_{\rm opt} =
% \frac{(mg)^{1/2}}{\rho^{1/2} w^{1/2}
% ( c_{\rm d} A )^{1/4} }.
% pr ( 363000.0 * 9.81 )**0.5 / ( 1.3 *exp(-1.007) * 64.4 )**0.5 / (0.03 * 180)**0.25
% 223 m/s
% * 3600 / 1500
% REDO THIS EXACTLY
$\star$ Frontal area estimated for 747 by taking cabin width (6.1\,m)
times estimated height of body (10\,m) and
adding double to allow for
the frontal area of
engines, wings, and tail;
for albatross, frontal area of 1 square foot estimated from a
photograph.
% Drag coefficient for 747 from
% www.aerospaceweb.org
% Cessna is same. Learjet is 0.02.
% Albatross assumed to be same as 747, though J Exp Biol paper by Hedenstrom and Liechti vol 204 (6) 1167-1175
% says ``large birds have cd=0.2''
%% C M Bishop paper says cd=0.1 is conceivable.
%% What does the nice MIT book say?
}
\label{tab747}
}
\end{table}%
The predicted optimal speeds (\tabref{tab747})
are more accurate than we have a right
to expect!
The 747's optimal speed is predicted to be 540\,\mph,
and the albatross's, 32\,\mph\ -- both very close to the true cruising
speeds of the two birds\index{bird!speed}\index{flight!optimal speed}
(560\,mph and 30--55\,mph respectively).
%% animals.
%% cruising speed of 747 is cruising speed 907km/h
%% mach 0.85
% Economical cruising speed 747: 900km/h.
% http://www.boeing.com/commercial/747family/pf/pf_400_prod.html
%% \section*{Notes}
Let's explore a few more predictions of our cartoon.
We can check whether the force (\ref{eq.forceplane}) is compatible with the
known thrust of the 747. Remembering that at the optimal speed, the two
forces are equal, we just need to pick one of them and double it:
\beqan
\mbox{force} &=&
\left. \frac{ \mbox{energy} }{ \mbox{distance} }\right|_{\rm ideal} =
\frac{1}{2} c_{\rm d} \rho \Ap v^2
+ \frac{1}{2} \frac{(mg)^2}{\rho v^2 \As}
\\
&=&
c_{\rm d} \rho \Ap v_{\rm opt}^2
%\\
%&=&
% c_{\rm d} \rho \Ap \left( \frac{(mg)^{1/2}}{\rho^{1/2} w^{1/2}
% ( c_{\rm d} \Ap )^{1/4} }\right)^2
\\
&=&
c_{\rm d} \rho \Ap \frac{mg}{\rho ( c_{\rm d} \Ap \As )^{1/2} }
\\
&=&
\left(\frac{c_{\rm d} \Ap}{\As}\right)^{1/2} {mg} .
\label{eq.forceplane2}
\eeqan
%% WHICH IS INDEPENDENT OF RHO
Let's define the filling factor $f_A$ to be the area ratio:
\beq
f_A = \frac{\Ap}{\As} .
\eeq
\marginfig{
% \begin{figure}
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{figs/plane3.eps}} }\\
\end{tabular}
\end{center}
% }{
\caption[a]{Frontal view of a Boeing 747, used to estimate the
frontal area $\Ap$ of the plane.
% This area is probably an
% underestimate of the effective frontal area, since the air doesn't flow
% straight past the wing.
The square has area $\As$ (the square of the wingspan). }
\label{fig.plane3}
}%
%% plane3.eps Frontal view of a Boeing 747. This area is probably an
%% underestimate of the effective frontal area, since the air doesn't flow
%% straight past the wing. ?
(Think of $f_A$ as the fraction of the square occupied by
the plane in figure \ref{fig.plane3}.)
%% -- perhaps $f\simeq 0.07$.) I am using 0.04.
Then
\beqan
\mbox{force} &=&
(c_{\rm d} f_A)^{1/2} {(mg)} .
\label{eq.forceplane3}
\eeqan
Interesting!
Independent of the density of the fluid through which
the plane flies, the required \ind{thrust}
(for a plane travelling at the optimal speed)
is just a dimensionless
constant $(c_{\rm d} f_A)^{1/2}$ times the weight of the plane.
This constant, by the way, is known as the \ind{drag-to-lift ratio}
of\index{lift-to-drag ratio} the plane.
(The lift-to-drag ratio has a few other names:
the \ind{glide number}, \ind{glide ratio},
\ind{aerodynamic efficiency},
\amargintab{t}{
\begin{tabular}{lr} \toprule
Airbus A320 & 17 \\
Boeing 767-200 & 19 \\
Boeing 747-100 & 18\\ % 17.7\\
Common Tern
% ({\em{sterna hirundo}})}
& 12\\
Albatross
% ({\em{diomeda exulans}})
& 20\\
\bottomrule
\end{tabular}
\caption[a]{Lift-to-drag ratios.
% Bigger is better.
% http://aerodyn.org/HighLift/ld-tables.html
% standard glideslope for approaching heathrow is 3 degrees
% That corresponds to 19.
}\label{tabLtD}
}%
or \ind{finesse}; typical values are shown in \tabref{tabLtD}.)
% Does my $f_A$ agree with the value obtained by computing $f_A$!?
Taking the jumbo jet's figures, $c_{\rm d} \simeq 0.03$ and
%% $f_A \simeq 0.07$,
%% the above is a guess from the picture; I don't think I ever used 0.07 in calculations
$f_A \simeq 0.04$,
%% 0.0434
%% 0.029 from using the figs I assumed before
we find the required \ind{thrust} is
\beq
(c_{\rm d} f_A)^{1/2} \, {mg} = 0.036\, mg = 130\,\kN .
\eeq
%% pr 363000.0*9.81 * (0.03 * 0.0434)**0.5
%% 128493.48982922
%% m = 363000 Kg fully laden << check whether it was including cargo etc
How does this agree with the 747's spec sheets?
In fact each of the 4 engines has a maximum thrust of about
250\,\kN, but this maximum thrust is used only during take-off.
%% http://www.boeing.com/commercial/747family/pf/pf_400er_prod.html
%% For a 747-400, 276,000N. (EACH according to wikipedia)
During cruise, the thrust is much smaller:
% http://www.anirudh.net/seminar/html/
% A 389kN engine will cruise at 70kN.
% A 276kN engine at 50.4kN.
the thrust of a cruising 747 is 200\,kN, just 50\% more than
our cartoon suggested.
%%
%% I wonder if the engines operate at maximum all the way, or just at takeoff?
%% When a 747 pilot lands, he aims to have
%% less than 40,000 kg of fuel on board, but is obliged to have...?
%% http://www.hoppie.nl/flightline/old/fl/logs.php/logs.php?forg=KBFI
%% see also notes/flight.tex
Our cartoon is a little bit off because our estimate of the
drag-to-lift ratio was a little bit low.
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Cessna.310Small.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Cessna.310.jpg.eps}}}
\\
\end{tabular} \\
\end{center}
\caption[a]{
\ind{Cessna} 310N:
{\eccol{60\,kWh per 100 passenger-km}}.
A Cessna 310 Turbo carries
6 passengers (including 1 pilot)
at a speed of
370\,km/h.
Photograph by Adrian Pingstone.
}
}This thrust can be used directly to deduce the
transport efficiency\index{transport!efficiency!plane}
achieved by any plane.
We can work out two sorts of transport efficiency:
the energy cost of moving {\em{weight}\/} around, measured in
% passenger--miles per gallon
kWh per {\tonne}-kilometre; and the energy cost of
moving people, measured in kWh per 100 passenger-kilometres.
\subsection{Efficiency in weight terms}
Thrust is a force, and a force is an
% useful
energy per unit distance.
The total energy used per unit distance is bigger by a factor
($1/\epsilon$), where $\epsilon$ is the efficiency of the engine, which we'll
take to be $1/3$.
Here's the {gross transport cost}, defined to be the
{energy per unit weight (of the entire craft) per unit distance}:
\beqan
\mbox{transport cost}
% ({kWh per {\tonne}--kilometre})
% \nonumber \\
&=&
\frac{ 1 }
{\epsilon}
\frac{ \mbox{force} }
{\mbox{mass}}
\\ & = & \frac{ 1 }
{\epsilon}
\frac{ (c_{\rm d} f_A)^{1/2} {mg} }
{ m}
\\ & = &
\frac{ (c_{\rm d} f_A)^{1/2} }
{\epsilon}
g .
\label{eqTe}
\eeqan
So the transport cost is just a dimensionless quantity (related
to a plane's shape and its engine's efficiency), multiplied by
$g$, the acceleration due to gravity.
Notice that this gross transport cost applies to all planes, but depends only
on three simple properties of the plane: its drag coefficient, the shape of the plane,
and its engine efficiency.
It doesn't depend on the size of the plane, nor on its weight, nor on the density
of air.
If we plug in $\epsilon = 1/3$ and assume a lift-to-drag ratio of 20
% , $c_{\rm d} = 0.03$, and $f_A \simeq 0.04$,
we find the gross transport cost of {\em{any}\/} plane, according to our cartoon, is
%%pr 3.0 * sqrt( 0.1*0.05 )
%% 0.212132034355964
%%pr 3.0 * sqrt( 0.03*0.04 )
%% 0.1
%%pr 3.0 / 20
%% 0.1
\[
0.15 \, g
\]
% WAS 0.212132034355 * 9.81 ((m / s) / s) = 0.578059794 (kWh per {\tonne}) per km
% IS 0.2832
% IS NOW: 1.47 J/kg/m -> 0.41
or
\[
0.4 \, \kWh / \mbox{\tonne-km}.
\]
\subsection{Can planes be improved?}
If engine efficiency can be boosted only a tiny bit by technological
progress, and if the shape of the plane has already been essentially
perfected, then there is little that can be done about the dimensionless quantity.
The transport efficiency is close to its physical limit.
The aerodynamics community say that the shape of planes could
be improved a little by a switch to blended-wing bodies, and that the drag coefficient
could be reduced a little by
% a technology called
\ind{laminar flow control}, a technology that reduces the growth of turbulence
over a wing by sucking a little air through small perforations in
the surface
\citep{BraslowBook}.
Adding laminar flow control to existing planes
would deliver a 15\% improvement in drag coefficient,
and the change of shape to blended-wing bodies is predicted to improve the
drag coefficient by about 18\%
\citep{GreenAviation}.
And \eqref{eqTe} says that the transport cost is proportional to the
square root of the drag coefficient, so improvements of $\cd$ by
15\% or 18\% would improve transport cost by 7.5\% and 9\% respectively.
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Learjet.60Small.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Learjet.60.eps}}}% was jpg and crashed
\\
\end{tabular} \\
\end{center}
\caption[a]{
``Fasten your cufflinks.''
% A Learjet 60
A Bombardier \ind{Learjet} 60XR
carrying 8 passengers at 780\,km/h
% \myurl{http://www.bombardier.com/}
has a transport cost of
{\eccol{150\,kWh per 100 passenger-km}}.
Photograph by Adrian Pingstone.
}
}
%Learjet 60 parked at Filton Airfield, Bristol, England.
%Taken by Adrian Pingstone in September 2004 and released to the public domain.
% Cessna 310N (UK registration G-YHPV, year of build 1968) at Kemble Airfield, Gloucestershire, England.
% Photographed by Adrian Pingstone in July 2005 and released to the public domain.
% \subsection{}
This gross transport cost is the energy cost of moving weight around, {\em{including the
weight of the plane itself}}.
To estimate the energy required to move freight by plane,\index{air freight!energy consumption}
per unit weight of freight,
we need to divide by the fraction that is cargo. For example, if a full
\ind{747} freighter is about $1/3$ cargo, then its transport cost
is
\[
0.45 \, g,
\]
or roughly 1.2\,kWh/\tonne-km.
%
% I watched a UK freight train, it has 22 full size containers and four half containers
This is just a little bigger than the transport cost of a truck, which is 1\,kWh/{{\tonne}-km}.
\subsection{Transport efficiency in terms of bodies}
Similarly, we can estimate a passenger transport-efficiency for a
\ind{747}.
\beqan
\lefteqn{\mbox{transport efficiency
({passenger--km per litre of fuel})
} } \nonumber \\
&=&
\mbox{number of passengers} \times \frac{ \mbox{energy per litre} }{
\frac{ \mbox{thrust} }
{\epsilon} }
\\ & = &
% jet fuel (135 000 btu) / US gal = 37 626 696.3 J / litre
%%% roughly 24\,000\,\kJ \, \per\, \litre
%%% 9 kWh/l is 32.4 MJ/l or 162 MJ/gal<> should use 37.6 MJ/l
\mbox{number of passengers} \times
\frac{ {\epsilon} \times \mbox{energy per litre} }
{ \mbox{thrust} }
\\
&=& 400 \times \frac{1}{3} \frac{ 38 \, \mbox{MJ} / \mbox{litre} }
{ 200\,000 \, \N }
\\
&=& 25 \,\mbox{passenger--km per litre}
\eeqan
This is a bit more efficient than a typical single-occupant car
% (40\,mpg)
(12\,\km \,\per\, \litre).
% 1 / (33 (miles per Imperial gallon)) = 11.6821994 km per litre
% We can find the actual efficiency of a 747
% by looking up its specifications:
%%% 747-???
% 10.45 kWh/l
%%% pr 100.0 * 199000 / 12700 / 416.0
%%% 3.46 l/100km each
%%% 747-400
%%% pr 100.0 * 240000 * 10.45 / 14205 / 416.0
%%% 42.44 kWh per 100 km
%%% pr 416 * 14205.0 / 240000
%%% 24.62 km per litre
% it is indeed 25\,passenger-km per litre.
So travelling by plane is more energy-efficient than car if
there are only one or two people in the car;
and cars are more efficient if there are three
or more passengers in the vehicle.
%%% _flight.tex further notes removed from here
\subsection{Key points}
We've covered quite a lot of ground! Let's recap the key ideas.
Half of the work done by a plane goes into {\em{staying up}};
the other half goes into {\em{keeping going}}.
The fuel efficiency at the optimal speed,
expressed as an energy-per-distance-travelled,
was found in the force (\ref{eq.forceplane3}), and
it was simply proportional to the weight of the plane; the constant
of proportionality is the drag-to-lift ratio, which is determined by
the shape of the plane. So whereas lowering speed-limits
for cars would reduce the energy consumed per distance travelled,
there is no point in considering speed-limits for planes. Planes that are up in the
air have optimal speeds, different for each plane, depending
on its weight, and they already go at their optimal speeds.
If you ordered a plane to go slower, its energy consumption would {\em{increase}}.
The only way to make a plane consume
fuel more efficiently is to put it on the ground and stop it.
Planes have been fantastically optimized, and there is no prospect
of significant improvements in plane efficiency.
(See pages \pageref{pPlaneTargets} and \pageref{pAirbus}
for further discussion of the notion
that new superjumbos are ``far more efficient'' than old jumbos;
and \pref{pTurboprop} for discussion of the notion that turboprops
are ``far more efficient'' than jets.)
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/Easyjet737SmallC.jpg.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Easyjet737LargeC.jpg.eps}}}
\\
\end{tabular} \\
\end{center}
\caption[a]{
Boeing 737-700:
{\eccol{30\,kWh per 100 passenger-km}}.
Photograph \copyright\ Tom Collins.
}
}
% Boeing 737-700:
% where is the calculation?
%% easyJet Boeing 737-700 G-EZJC departing Bristol Airport. Photo copyright Tom Collins
% Boeing 737-700,
% photo copyright Tom Collins.
% http://links.jstor.org/sici?sici=0908-8857(199606)27%3A2%3C118%3AMWSCCS%3E2.0.CO%3B2-R
% article saying that swas crossing iceland to scotland have to use
% fat weighing 25% of their lean body mass
\subsection{Range}
Another prediction we can make is, what's the range of a plane or bird
-- the biggest distance it can go without refuelling?\index{bird!range}\index{range!of bird}
You might think that bigger planes have a bigger range, but the prediction of
our model is startlingly simple.
The range of the plane, the maximum distance it can go before refuelling, is
proportional to its velocity and to the total energy of the fuel,
and inversely proportional to the rate at which it guzzles fuel:
\beq
\mbox{range} =
v_{\rm opt} \frac{\rm energy}{\rm power}
= \frac{\mbox{energy}\times \epsilon}{\rm force} .
\eeq
Now, the total energy of fuel is the calorific value of the fuel, $C$ (in joules per kilogram),
times its mass; and the mass of fuel is some fraction $f_{\rm fuel}$
of the total mass of the plane.
So
\beq
\mbox{range} = \frac{\mbox{energy} \, \epsilon}{\rm force}
= \frac{ C m \epsilon f_{\rm fuel}}{ (c_{\rm d} f_A)^{1/2} {(mg)} }
% = \frac{ C \epsilon f_{\rm fuel}}{ (c_{\rm d} f_A)^{1/2} {g} }
= \frac{ \epsilon f_{\rm fuel}}{ (c_{\rm d} f_A)^{1/2} }
\frac{C}{g} .
\eeq
It's hard to imagine a simpler prediction:
the range of any bird or plane is the product of a dimensionless
factor
$\left(\frac{ \epsilon f_{\rm fuel}}{ (c_{\rm d} f_A)^{1/2} }\right)$
which takes into account the engine efficiency, the drag coefficient, and
the bird's geometry, with
a fundamental distance,
\[
\frac{C}{g},
\]
which is a property of the fuel and gravity, and nothing else.
No bird size, no bird mass, no bird length, no bird width;
no dependence on the fluid density.
So what is this magic length?
It's the same distance whether the fuel
is goose fat or jet fuel: both these fuels are essentially
hydrocarbons (CH$_2$)$_n$.
Jet fuel has a calorific value of $C = 40$\,MJ per kg. The distance
associated with jet fuel is
\beq
d_{\rm Fuel} =
\frac{C}{g}
= {4000\,\km} .
\eeq
% Back to the birds.
The range of the bird is the intrinsic range of the fuel,
\amarginfignocaption{t}{
\small
You can think of $d_{\rm Fuel}$
as the distance that the fuel could throw itself if it
suddenly converted all its chemical energy to kinetic energy and launched
itself on a parabolic trajectory with no air resistance.
[To be precise, the distance achieved by the optimal parabola is
twice $C/g$.] This distance is also the {\em{vertical}\/} height to which the fuel could throw
itself if there were no air resistance.
Another amusing thing to notice is that
the calorific value of a fuel $C$, which I gave in joules
per kilogram, is also a squared-velocity (just as the energy-to-mass
ratio $E/m$ in \ind{Einstein}'s $E=mc^2$ is a squared-velocity, $c^2$):
$40\times 10^6$\,J per kg is $(6000\,\m/\s)^2$.
So one way to think about fat is ``\ind{fat is 6000 metres per second}.''
% 12\,000 miles per hour}''.
If you want to lose weight by going jogging, 6000 m/s
(12\,000 mph) is the speed you should aim for in order
to lose it all in one giant leap.
}%
4000\,km,
times a factor
$\left(\frac{ \epsilon f_{\rm fuel}}{ (c_{\rm d} f_A)^{1/2} }\right)$.
If our bird has engine efficiency $\epsilon=1/3$ and
% I switched to the
drag-to-lift ratio
$(c_{\rm d} f_A)^{1/2} \simeq 1/20$, and if nearly half of the bird is fuel
(a fully-laden \ind{747} is 46\% fuel),
we find that all birds and planes, of whatever size,
% (as long as they have roughly the same geometry),
% 1.0/6.0 / 0.03
% was 0.03 , changed to 1/20
% 1.0/6.0 / (1/20) * 4000
have the same range:
about three times the fuel's distance -- roughly 13\,000\,km.
%% actual mass of plane is 170 without fuel, and fuel is same again; (168)
%% takeoff weight fully laden is 363
This figure is again close to the true answer:
the nonstop \ind{flight record}\index{record, flight} for a \index{747!flight record}747
(set on March 23--24, 1989)
% 10500 miles is 16898 km
was a distance of 16\,560\,km.
And the claim that the range is independent of bird size is
supported by the observation that birds of all sizes, from great geese
down to dainty swallows and arctic tern, migrate
intercontinental distances.
%
The longest recorded non-stop flight by a bird was\index{bird!longest flight}
a distance of 11\,000\,km, by a \ind{bar-tailed godwit}\index{godwit}.\nlabel{pgodwit}
How far did \index{Fossett, Steve}{Steve Fossett} go in
the specially-designed
\ind{Scaled Composites} Model 311 \ind{Virgin} Atlantic \ind{GlobalFlyer}?
% 25766 feb 2006.
41\,467\,km.
\tinyurl{33ptcg}{http://www.stevefossett.com/html/main_pages/records.html}
% 6389.3 miles 42\,469\,km.
% The Longest Distance Aircraft Flight - The Absolute Non-Stop Distance Record
%% OK, how about the passenger-miles per gallon?
An unusual plane:
83\% of its take-off weight was fuel; the flight made careful use of the
jet-stream to boost its distance.
Fragile, the plane had several failures along the way.
One interesting point brought out by this cartoon:
if we ask ``what's the optimum air-density to fly in?'',
we find that the {\em{thrust}\/} required (\ref{eq.forceplane2}) at the optimum speed is independent
of the density. So our cartoon plane would be equally happy
to fly at any height; there isn't an optimum density;
the plane could achieve the same miles-per-gallon
in any density; but the optimum {\em{speed}\/} does depend on the
density ($v^2 \sim 1/\rho$, \eqref{eq.optV}).
So all else being equal, our cartoon plane would have the shortest
journey time if it flew in the lowest-density air possible.
Now real engines' efficiencies aren't independent of speed and air density.
As a plane gets lighter by burning fuel, our cartoon says
its optimal speed at\index{flight!optimum height}
a given density would reduce
($v^2 \sim mg/(\rho (c_{\rm d} \Ap\As)^{1/2})$).
So a plane travelling in air of constant density should
slow down a little as it gets lighter.
But a plane can both keep going at a {\em{constant speed}\/}
and continue flying
at its {\em{optimal}\/} speed if it increases its altitude so as to reduce the
air density.
%% As a long-distance plane gets lighter,
%% the optimal altitude for flight increases.
% typically from 31,000 feet to 39,000 feet by the end of the flight.
Next time you're on a long-distance flight, you could check
whether the \ind{pilot} increases the cruising height\index{height, of flight}
from, say, 31\,000 feet to 39\,000 feet by the end of the flight.
\subsection{How would a hydrogen plane perform?}
We've already argued that the efficiency\index{hydrogen!plane}
of flight, in terms of energy per {\tonne}-km,
is just a simple dimensionless number times $g$.
Changing the fuel isn't going to change this
fundamental argument. Hydrogen-powered planes
are worth discussing if we're hoping to reduce
climate-changing emissions. They might also have better
range. But don't expect them to be radically more
energy-efficient.
\subsection{Possible areas for improvement of
plane efficiency}
Formation flying\index{formation flying}\index{bird!formation flying}
in the style of \ind{geese} could
give a 10\% improvement in fuel efficiency (because the \ind{lift-to-drag
ratio} of the formation is higher than
that of a single aircraft), but this trick relies, of course, on the
geese wanting to migrate\index{migration} to the same destination at the same time.
Optimizing the hop lengths:\nlabel{OptHop}
long-range planes (designed for a range of say 15\,000\,km)
are not quite as fuel-efficient as shorter-range planes, because
they have to carry extra fuel, which makes less space for
cargo and passengers. It would be more energy-efficient
to fly shorter hops in shorter-range planes.
% source page 4.2.1 (p474) of greens.pdf GreenAviation
The sweet spot is when the hops are about 5000\,km long, so
typical long-distance journeys would have one or
two refuelling stops \citep{GreenAviation}. Multi-stage
long-distance flying might be about 15\% more fuel-efficient;
but of course it would introduce other costs.
\subsection{Eco-friendly aeroplanes}
Occasionally you may hear about people making
eco-friendly aeroplanes.
Earlier in this chapter, however, our cartoon
made the assertion that the transport cost of {\em{any}\/} plane
is about
\[
0.4 \, \kWh / \mbox{{\tonne}-km}.
\]
According to the cartoon, the only ways in which a plane could
significantly improve on this figure are to reduce air resistance
(perhaps by some new-fangled vacuum-cleaners-in-the-wings trick)
or to change the geometry of the plane (making it look more like
a glider, with immensely wide wings compared to the fuselage,
or getting rid of the fuselage altogether).
So, let's look at the latest news story about ``eco-friendly aviation''
and see whether one of these planes can beat
the $0.4$\,kWh per {{\tonne}-km} benchmark.
% it's a load of hype
If a plane uses less than 0.4\,kWh per {{\tonne}-km}, we might conclude that the cartoon is defective.
%% http://news.bbc.co.uk/1/low/technology/7384788.stm
% another article about ^^ electric plane see taurusPlane image
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ELECTRA3.eps}}}\\
\end{tabular} \\
\end{center}
\caption[a]{
The Electra F-WMDJ:
\eccol{11\,kWh per 100\,\pkm}.
Photo by Jean--Bernard Gache.
\myurlb{www.apame.eu}{http://www.apame.eu/}
}
}
% energy coefficent 2% of petrol
% APAME Electra December 23rd, 2007
% http://www.timesonline.co.uk/tol/news/world/europe/article3123681.ece
The \ind{Electra}, a wood-and-fabric single-seater,
flew for 48 minutes for 50\,km around the southern Alps
on 23rd December, 2007
\tinyurl{6r32hf}{http://www.theaustralian.news.com.au/story/0,25197,23003236-23349,00.html}.
The Electra has a 9-m wingspan and an 18-kW
% http://www.acv05.fr/News05.html
% a 25\,hp 18.64
electric motor powered by 48\,kg of lithium-polymer batteries.
% Ms Lavrand said the fuel cost per hour of the Electra was E1 compared with about E60 ($100) for an equivalent petrol-driven machine.
The aircraft's take-off weight is
265\,kg
(134\,kg of aircraft, 47\,kg of batteries, and
84\,kg of human cargo).
% On 23rd December, 2007 it flew a distance of 50\,km.
% at 75\,km/h.
% Finesse 13.
If we assume that the battery's energy density was 130\,Wh/kg,
and that the flight used 90\% of a full charge (5.5\,kWh),
% doublecheck: 18kW * 48/60 is 14.4 kWh (if the engine goes full power)
% but it doesn't. It has extra power for climb.
% 11 kWh per 100 pkm
the transport cost was roughly
% 1e-3*130*0.9*47 / (50*0.265)
\[
0.4\,\kWh/\mbox{\tonne-km},
\]
which exactly matches our cartoon.
This electrical plane is
not a lower-energy plane than a normal fossil-sucker.
% Electraflyer - C all electric airplane based on a Moni Motorglider
% 5.6kWh (35kg) battery. blogger said range 1.5-2 hours at 70mph.
% where that info from?
% The batteries for the plane came from Valence Technology.
Of course, this doesn't mean that electric planes are
not interesting.
% the energy consumption of a plane is not the only issue.
If one could replace traditional planes by alternatives with equal
energy consumption but no carbon emissions, that would certainly be a useful
technology.
And, as a person-transporter, the Electra delivers
a respectable \eccol{11\,kWh per 100\,\pkm}, similar to the electric
car in our transport diagram on \pref{passenger}.
But in this book the bottom line is
always: ``where is the energy to come from?''
\subsection{Many boats are birds too}
Some time after writing this cartoon of flight,
I realized that it applies to more than just the
birds of the air -- it applies to hydrofoils,\index{hydrofoil}
and to other high-speed \ind{watercraft}\index{boats as planes}\index{planes!boats as an example of}
too -- all those\index{flight!boats that fly}
that ride higher in the water when moving.
\begin{figure}
\figuremargin{\small
\begin{tabular}{@{}cc}
\mbox{\epsfbox{metapost/hydrof.155}}&
\mbox{\epsfbox{metapost/hydrof.156}}
\\
{\sf side view} & {\sf front view} \\
\end{tabular}
}{
{\mbox{\epsfxsize=53mm\epsfbox{../../images/HydrofoilC.eps}}}\\
\caption[a]{Hydrofoil.\index{hydrofoil}
Photograph by Georgios Pazios.
}
\label{fig.hydrof}
}
\end{figure}
\Figref{fig.hydrof} shows the principle of the hydrofoil.
The weight of the craft is supported by a tilted
underwater wing, which may be quite tiny
compared with the craft.
The wing generates lift by throwing fluid down, just like the plane of
\figref{fig.sausage}.
If we assume that the drag is dominated by the drag on the wing, and that
the wing dimensions and vessel speed have been optimized to minimize the
energy expended per unit distance, then
the best possible
transport cost, in the sense of energy per {\tonne}-kilometre,
will be just the same as in
\eqref{eqTe}:
\beq
\frac{ (c_{\rm d} f_A)^{1/2} }
{\epsilon} g ,
\eeq
where $c_{\rm d}$ is the drag coefficient of the underwater wing, $f_A$ is
the dimensionless area ratio defined before, $\epsilon$ is the engine efficiency, and
$g$ is the acceleration due to gravity.
Perhaps $c_{\rm d}$ and $f_A$ are not quite
the same as those of an optimized aeroplane.
But the remarkable thing about this
theory is that it has no dependence on the density of
the fluid through which the wing is flying.
So our ballpark prediction is that the
transport cost (energy-per-distance-per-weight, including the vehicle weight)
of a hydrofoil is {\em the same\/} as the
transport cost of an aeroplane! Namely, roughly 0.4\,kWh per {\tonne-km}.
For vessels that skim the water surface, such as high-speed catamarans
and water-skiers, an accurate cartoon should also
include the energy going into making waves, but I'm tempted to guess that
this hydrofoil theory is still roughly right.
I've not yet found data on the transport-cost of a hydrofoil,
but some data for a passenger-carrying \ind{catamaran}
travelling at 41\,km/h seem to
agree pretty well:
% boat.tex ferry.tex
it consumes roughly 1\,kWh per {\tonne}-km.\nlabel{pfastcat}
It's quite a surprise to me to learn that
an island hopper who goes from island to island by plane
not only gets there faster than someone who hops by boat -- he quite
probably uses less energy too.
% new material BLIMPS? blimp0.tex
\section{Other ways of staying up}
\subsection{Airships}
This chapter has emphasized that planes can't be made more energy-efficient
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Akron.eps}}}\\
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/Spirit.eps}}}\\
\end{tabular}
\end{center}
\caption[a]{
The 239\,m-long \ind{USS Akron} (ZRS-4) flying over Manhattan.
It weighed 100\,t and could carry 83\,t.
Its engines had a total power of 3.4\,MW, and it could transport 89
personnel and a stack of weapons
at 93\,km/h. It was also used as an aircraft carrier.
% speed 93 km/h range 20,000 km?! 133 km/h maximum
% 8x420kW
% akron was helium filled.
% Spirit of Dubai; photo by Arnold Nayler.
}
}
by slowing them down, because any benefit from reduced air-resistance
is more than cancelled by having to
chuck air down harder. Can this problem be solved by
switching strategy: not throwing air down, but being as light
as air instead?
An \ind{airship}, \ind{blimp}, \ind{zeppelin},
or \ind{dirigible}
uses an enormous \ind{helium}-filled
\ind{balloon}, which is lighter than air,
to counteract the weight of its little cabin.
The disadvantage of this strategy is that the enormous balloon
greatly increases the air resistance of the vehicle.
The way to keep the energy cost of an airship (per weight, per distance)
low is to move slowly, to be fish-shaped, and to be very large and long.
Let's work out a cartoon of the energy required by an idealized airship.
% L = 2R R = L/2
\newcommand{\blimpL}{\ensuremath{L}}
I'll assume the balloon is ellipsoidal, with cross-sectional
area $A$ and length $\blimpL$.
\marginfig{
\mbox{\epsfbox{metapost/blimp.55}}
\caption[a]{An ellipsoidal airship.
}
\label{fig.blimp0}
}%
The volume is $V= \frac{2}{3} A \blimpL$. If the airship floats stably
in air of density $\rho$, the total mass
of the airship, including its cargo and its helium, must be
$m_{\rm total} = \rho V$.
If it moves at speed $v$, the force of air resistance is
\beq
F = \frac{1}{2} \cd A \rho v^2 ,
\eeq
where $\cd$ is the drag coefficient, which, based on aeroplanes, we
might expect to be about 0.03.
The energy expended, per unit distance, is equal to $F$ divided
by the efficiency $\epsilon$ of the engines.
So the gross
transport cost -- the energy used per unit distance per unit mass --
is
\beqan
\frac{F}{ \epsilon m_{\rm total}}& =& \frac{ \frac{1}{2} \cd A \rho v^2 }
{ \epsilon \rho \frac{2}{3} A \blimpL }
\\
&=& \frac{3}{4 \epsilon } \cd \frac{ v^2 }
{ \blimpL }
\eeqan
That's a rather nice result!
The gross transport cost of this idealized airship depends only on its
speed $v$ and length $\blimpL$, not on the density $\rho$
of the air, nor on the airship's frontal area $A$.
This cartoon also applies without modification to \ind{submarine}s.
The gross transport cost (in kWh per ton-km)
of an airship is just the same as the gross transport
cost of a submarine of identical length and speed. The submarine will
contain 1000 times more mass, since water is 1000
times denser than air; and it will cost 1000 times more to
move it along. The only difference between the two will be the advertising
revenue.
So, let's plug in some numbers.
Let's assume we desire to travel at a speed of 80\,km/h (so that
crossing the Atlantic takes three days). In SI units, that's 22\,m/s.
Let's assume an efficiency $\epsilon$ of $1/4$.
To get the best possible transport cost, what is
% 80km/h is 22.2m/s
the longest blimp we can imagine?
The Hindenburg was 245\,m long.
% and was powered by 4400hp.
If we say $\blimpL = 400$\,m,
we find the transport cost is:
\[%beqan
\frac{F}{ \epsilon m_{\rm total}}
% &=& \frac{3}{4 \epsilon } \cd \frac{ v^2 }
% { \blimpL }
\:=\: {3} \times 0.03 \frac{ (22\,\m/\s)^2 }
{ 400\,\m } \:=\: 0.1\,\m/\s^2
% 0.1089
\:=\: \eccol{0.03\,\mbox{kWh/\tkm}}.
% 0.03025
\]%eeqan
% 1\,kWh/\tkm & 3.6\,m/s$^2$
If useful cargo made up half of the vessel's mass, the
net transport cost of this monster airship
would be \eccol{0.06\,\mbox{kWh/\tkm}} -- similar to rail.
% Triton, longest submarine: 136.4 m
% Top speed, submerged: 50 km/h.
% 172 crew.
% Displacement 7773\,t when submerged.
% According to the cartoon,
% 13.9m/s
% 3* 0.03 * 13.9**2 / 136.4
% 0.13\,m/s$^2$, or 0.035\,kWh/\tkm.
% http://news.bbc.co.uk/1/hi/sci/tech/769642.stm
% cargolifter is meant to carry 160 t at 100 km/h and is 260m long
% http://www.guardian.co.uk/world/2007/nov/20/theairlineindustry.japan
% 75m long tokyo
\amarginfig{t}{
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ekranoplanBelyaev.eps}}}\\[0.1in]
{\mbox{\epsfxsize=53mm\epsfbox{../../images/ekranLunInCruiseBelyaev.eps}}}\\
\caption[a]{The \ind{Lun} \ind{ekranoplan} --
slightly longer and heavier than a Boeing 747.
Photographs: A. Belyaev.}
}%
\subsection{Ekranoplans}
The \ind{ekranoplan}, or water-skimming wingship,
is a ground-effect aircraft:
an aircraft that flies very close to the surface of the water, obtaining its lift
not from hurling air down like a plane,
nor from hurling water down like a hydrofoil or speed boat,
but by sitting on a cushion of compressed air sandwiched between its
wings and the nearby surface. You can demonstrate the ground effect
by flicking a piece of card across a flat table.
% ; curling the leading edge
% of the paper upwards a little may help.
Maintaining this air-cushion requires very little
energy, so the ground-effect aircraft, in energy terms, is a lot like a
surface vehicle with no rolling resistance.
Its main energy expenditure is associated with air resistance.
Remember that for a plane at its optimal speed, half of its energy
expenditure is associated with air resistance, and half with throwing
air down.
The Soviet Union developed the ekranoplan as a military transport vehicle and
missile launcher in the \ind{Khrushchev} era.
% 550 ton, 125 ton, 400 ton Lun-class carry 100 t cargo
% According to \tinyurl{4p3yco}{http://www.fas.org/man/dod-101/sys/ship/row/rus/903.htm},
% Lun: eight NK-87 turbofan engines rated at 28,660 lb trust each
% that is 13000kg do I multiply by g? Yes
% 127 kN total 1000 kN
% max takeoff weight 400t exactly
% 341 mph cruise
The Lun ekranoplan could travel at 500\,km/h, and the total thrust of
its eight engines was 1000\,kN, though this total was not required once
the vessel had risen clear of the water.\nlabel{LunE}
Assuming the cruising thrust was one quarter of the
maximum; that the engines were 30\% efficient;
and that of its 400-ton weight, 100 tons were
cargo, this vehicle had a net
freight-transport cost of \eccol{2\,kWh per ton-km}.
% 1000000 newtons / 4 / 0.3 / 100 tons in kWh per ton-km
% picture with helicopter: A. Belyaev
% picture: A. Belyaev
% source http://www.se-technology.com/wig/html/main.php?open=showcraft&code=0&craft=26
% \tinyurl{47wvvs}{http://www.se-technology.com/wig/html/main.php?open=showcraft&code=0&craft=26}
I imagine that, if perfected for non-military freight transport,
the ekranoplan might have a freight-transport cost about half that of
an ordinary aeroplane.
% modern ekranoplan companies
%The AF8/SF8 built by Fischer Flugmechanik and AFD (Germany) for Flightship Ground Effect
% (Australia) 2001.
% The Hoverwing HW2VT scale prototype of 80 seat ferry by Fischer Flugmechanik
% The TY-1 by China Academy of Science and Technology (China)
% Amphistar/Aquaglide by Centre of Ekranoplan Technologies ALSIN (Russia)
% 747 is 360t takeoff weight
% hovercraft? 45 knots typical
% 160 tonnes 60 knots 1968 cross-channel hov. BH4
% BHC SR-N4 The world's largest non-military hovercraft, carrying 418 passengers and 60 cars
% The first SR-N4 had a capacity of 254 passengers and 30 cars, and a top speed of 83 knots (154 km/h/96 mph).
% wave-piercing catamarans use less fuel
% To maintain speed the engines were upgraded to four 3,500 shaft horsepower (2,610 kW) Rolls-Royce gas turbines
% mark 3: up to 60 cars and 418 passengers (112 t maximum)
% 4 hours, uses 2800 imperial gallons
% cruise: 111 km/h
% energy cost 1: assume engines 30% efficient
% 4 * 2610 kW / 0.30 / (111 km/hour) / 418 in kWh / km
% 75 kWh per 100 pkm
% energy cost 2:
% 2800 imperial gallons * 10 kWh / litre / (111 km/hours * 4 hours) /418 in kWh/km
% 69 kWh per 100 pkm
% freight energy cost:
% 2800 imperial gallons * 10 kWh / litre / (111 km/hours * 4 hours) /112 in kWh/km
% 2.6 kWh per tkm.
% preferred image
% jpeg2ps SRN4_Hovercraft_Mountbatten_Class0C.jpg > SRN4_Hovercraft_Mountbatten_Class0C.eps
\section{Mythconceptions}
\beforeqa
\qa{The plane was going anyway, so my flying was energy-neutral.}{
This is false for two reasons. First, your extra weight on the plane
requires extra energy to be consumed in keeping you up.
Second, airlines respond to demand by flying more planes.
% example --
% United Airlines flights between Burbank and SFO --
% one departure every 20 mins? Each day, they would then cancel
% several of the flights and lump all the passengers into
% an appropriate number of planes.
}
\beginfullpagewidth
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{p747da}]
{\nqs{Boeing 747.}}
Drag coefficient for \ind{747} from
\myurl{www.aerospaceweb.org}.
Other 747 data from
\tinyurl{2af5gw}{http://www.airliners.net/info/stats.main?id=100}.
Albatross facts from
\tinyurl{32judd}{http://www.wildanimalsonline.com/birds/wanderingalbatross.php}.
% Albatross estimated drag coefficient (0.1)
%% assumed to be same as 747, though
% based on C M Bishop paper
% -- says $\cd=0.1$ is conceivable.
\item[\npageref{peffEng}]
{\nqs{Real jet engines have an efficiency of about $\epsilon = 1/3$.}}
% ***
% (``Specific fuel consumption.'')
% \myurl{http://adg.stanford.edu/aa241/propulsion/sfc.html}
% VV
Typical engine efficiencies are in the range 23\%--36\%
[\myurlb{adg.stanford.edu/aa241/propulsion/sfc.html}{http://adg.stanford.edu/aa241/propulsion/sfc.html}].
%% and especially http://www.grida.no/climate/ipcc/aviation/097.htm
%% VV
For typical aircraft, overall engine efficiency ranges between 20\% and 40\%,
with the best bypass engines delivering 30--37\% when cruising
[\myurlb{www.grida.no/climate/ipcc/aviation/097.htm}{http://www.grida.no/climate/ipcc/aviation/097.htm}].
% see also
%% http://www.grida.no/climate/ipcc/aviation/095.htm#741
%% and especially http://www.grida.no/climate/ipcc/aviation/097.htm
%% `For typical aircraft, overall efficiency ranges between 20 and 40\%'.
%% best bypass engines 30 to 37% at cruise.
You can't simply pick the most efficient engine however,
since it may be heavier (I mean, it may have bigger
mass per unit thrust), thus reducing
overall plane efficiency.
% Overall efficiency:
% ``The last piston-powered
% aircraft were as fuel-efficient as the current average jet.''
% \myurl{http://www.transportenvironment.org/Downloads-index-req-getit-lid-398.html}
% [Source missing
% \myurl{http://www.transportenvironment.org/}
\item[\npageref{pgodwit}]
{\nqs{The longest recorded non-stop flight by a bird\ldots}}
{\em New Scientist} 2492.
``Bar-tailed godwit is king of the skies.''
26 March, 2005.
% Magazine issue 2492.
% Tuesday,
11 September, 2007:
Godwit flies 11\,500\,km non-stop from Alaska to New Zealand.
\tinyurl{2qbquv}{http://news.bbc.co.uk/1/low/sci/tech/6988720.stm}
%% http://en.wikipedia.org/wiki/Bar-tailed_godwit
%% http://en.wikipedia.org/wiki/Image:BartailedGodwit24.jpg
% public domain image
\item[\npageref{OptHop}]
{\nqs{Optimizing hop lengths:
the sweet spot is when the hops are about 5000\,km long}}.
Source:
% page 4.2.1 (p474) of greens.pdf
\cite{GreenAviation}.
\item[\npageref{pfastcat}]
{\nqs{Data for a passenger-carrying \ind{catamaran}}.}
From \tinyurl{5h6xph}{http://www.goldcoastyachts.com/fastcat.htm}:
Displacement (full load) 26.3 tons.
On a 1050 nautical mile voyage she consumed just 4780 litres of fuel.
I reckon that's a weight-transport-cost of 0.93\,kWh per {\tonne}-km.
I'm counting the total weight of the vessel here, by the way.
The same vessel's {\em{passenger}}-transport-efficiency is roughly
35\,kWh per 100\,\pkm.\index{transport!efficiency!catamaran}
% added Sat 11/10/08
\item[\npageref{LunE}]
{\nqs{The Lun ekranoplan.}}
Sources: \url{www.fas.org}
\tinyurl{4p3yco}{http://www.fas.org/man/dod-101/sys/ship/row/rus/903.htm},
\citep{TaylorEkran}.
\item[Further reading:]
\cite{flight},
% %Tennekes
\cite{Wings99}.
\end{notelist}
\normalsize
\ENDfullpagewidth
\gset\chapter{\gcol{Solar II}}
\label{ch.solar2}
%\section{Solar biomass II}
\marginfig{
%\begin{figure}\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=53mm\epsfbox{../../images/cam/twotreesS.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/cam/twotrees.eps}}%
\\
%{\mbox{\epsfxsize=53mm\epsfbox{../../images/cam/twotrees3.eps}}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{Two trees.
% , yesterday.
}
}
On \pref{pBioOptions} we listed four solar biomass options:\index{biofuel}
%\begin{inparaenum}%
\ben
\item
``Coal substitution.''
\item
``Petroleum substitution.''
\item
Food for humans or other animals.
\item
Incineration of agricultural by-products.
%\end{inparaenum}%
\een
%
We'll estimate the maximum plausible contribution of each of these
processes in turn.
In practice, many of these methods require so much
energy to be put {\em{in}\/} along the way that they are
scarcely net contributors (\figref{fig.biofueld}). But in what follows, I'll
ignore such embodied-energy costs.
% Let's now look in a little more detail at specific bio-solar solutions.
\section{Energy crops as a coal substitute}
%\section{Coal substitute}
If we grow in Britain
\ind{energy crops} such as \ind{willow}, \ind{miscanthus}, or \ind{poplar}
(which have an average power of 0.5\,\W\ per square metre of land),
then shove them in a 40\%-efficient power station, the resulting power per unit area
is \pdcol{0.2\,\Wmm}.\nlabel{pdWood}
If one eighth of Britain (500\,m$^2$ per person) were covered in these plantations, the resulting power
would be
% 800m**2 -> 160 W \OliveGreen{4\,kWh/d per person}.
% 500m**2 -> 250W before (6.25kWh) and 100W after. (2.5kWh)
\OliveGreen{2.5\,kWh/d per person}.
\section{Petroleum substitution}
% Tim Dunne
% http://www.nervouscyclist.org/Favourite/00000015.jpg
There are several ways to turn plants into liquid fuels.\index{liquid fuels!from plants}
I'll express the potential of each method in terms of its power per unit area
(as in \figref{fig.plants155}).
%% In the UK, the main plant oil crop is oilseed rape (OSR).
% OSR yields around 1300 litres of biodiesel per hectare planted.
\subsection{Britain's main biodiesel crop, rape}
Typically, rape is sown in September and harvested the following August.
% source http://www.defra.gov.uk/
Currently 450\,000 hectares of oilseed rape\index{biofuel!rape}\index{rape biodiesel}
are grown in the UK each year. (That's 2\% of the
UK.)
\amarginfig{c}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\epsfxsize=53mm\epsfbox{../../images/rapeC.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
Oilseed rape.\index{oilseed rape}
If used to create biodiesel, the power per unit area of rape is
0.13\,\Wmm.\index{plant yields}\index{power density!rape}\index{power density!biofuel}\index{biofuel!power density}
Photo by Tim Dunne.
}\label{rape}
}
%
% 0.0184
% , or 0.2\,Waleses.)
% 0.214
% Diesel costs farmers 18.3p per litre.
%% 1,9 million tons per year (2005) in UK. Rape yield (seeds)
%% 3 t per ha PER YEAR. 40% to oil; 97% to biodiesel.
% http://www.nnfcc.co.uk/metadot/index.pl?id=2191;isa=Category;op=show
% 1300 litres
Fields of rape produce 1200 litres of biodiesel per hectare per year;
% NET
% they mention 129 litres in and 1365 litres out (which is from
% 3.25 {\tonne}s of crop); then they say
% another minimal-cultivation method has a yield smaller by a factor (2.75/3.25):
% 82 litres in 1155 litre out (per ha)
% [net production: 1236 , 1073.]
biodiesel has an energy of 9.8\,kWh per litre;\nlabel{pRape}
% 9.83
So that's a power per unit area of \pdcol{0.13\,\Wmm}.
%% http://www.bcsbioscience.co.uk/BCS/BIOCMS/biocms.nsf/resourceview/OSR%20Income%20and%20Benefits%20-%20Dec%2003.pdf/$File/OSR%20Income%20and%20Benefits%20-%20Dec%2003.pdf?OpenElement
% who are advocating a GM herbicide-tolerant rape they have devised.
% They claim 80 in and 1365 out for GM.
%
% I think this net figure allows for energy inputs.
% But does it include all of them?
% The processing of vegetable oil uses methanol
% derived from natural gas.
% 1 {\tonne} of oilseed rape yields 409\,l,
% which turns into 473\,l of biodiesel
% but only with the help of 80\,l of methanol.
%% 9.83 kWh/l Biodiesel 35.39MJ ;
%% in simple energy terms that means 1696MJ of extra methanol energy needed
%% when delivering 16739MJ -- hmm, just 10%
If we used 25\% of Britain for oilseed
rape, we'd obtain biodiesel with an energy content of
% 1000 * 0.13 = 130W
\OliveGreen{3.1\,kWh/d per person}.
\subsection{Sugar beet to ethanol}
Sugar beet, in the UK, delivers\index{sugar beet}\index{biofuel!sugar beet}
an impressive yield of 53\,t per hectare per year.\nlabel{pSugarB}
%http://www.esru.strath.ac.uk/EandE/Web_sites/02-03/biofuels/references.htm#ref17
%http://statistics.defra.gov.uk/esg/default.asp
And 1\,t of sugar beet makes 108 litres of bioethanol.
Bioethanol has an energy density of\index{bioethanol!from sugar beet}
6\,kWh per litre, so this process has
a power per unit area of
% (What energy inputs required?)
%
% 21.1e6 J/l * 53e3kg/ha/year * 0.108l/kg in W/sq m
\pdcol{0.4\,\Wmm}, not accounting for energy inputs required.
% 0.382725
%% In 2006 UK consumed 18 M t gasoline,
%% 26 Mt diesel. UK jet fuel usage was 12 Mt.
%% UK could produce 2.5% of its diesel as biodiesel
%% but http://www.guardian.co.uk/business/2008/apr/09/greenbusiness.biofuels
%% "splash and dash" imports from USA have killed a UK refiner.
%% (this means taking pure biodiesel to USA, adding a drop
%% of diesel (to get big subisdy), and immediately shipping to EU)
\subsection{Bioethanol from sugar cane}
Where sugar cane can be produced (\eg, Brazil)\index{ethanol!from sugar cane}
production is 80\,tons per hectare per year, which yields
about 17\,600\,l of ethanol. Bioethanol has an energy density of
6\,kWh per litre, so this process has\index{bioethanol!from sugar cane}
% Ethanol 23.4 MJ/l ; bioehtanol 21.6 MJ/l
% 21.6 MJ * 17600 / 1 year / 1 ha in W / m**2
a power per unit area of \pdcol{1.2\,\Wmm}.\index{biofuel!sugar cane}
\subsection{Bioethanol from corn in the USA}
The power per unit area of bioethanol from corn is astonishingly low.
Just\index{bioethanol!from corn}\index{ethanol!from corn}\index{biofuel!from corn}
for fun, let's report the numbers first in archaic units.
% (4050\,m$^2$)
1 acre
produces 122 bushels of corn per year,
which makes $122\times2.6$ US gallons of ethanol, which
at 84\,000\,BTU per gallon would mean
a power per unit area of {\pdcol{0.2\,\Wmm}}; however,
the energy {\em{inputs}\/} required to process the corn into ethanol
amount to 83\,000\,BTU per gallon; so 99\% of the energy
produced is used up by the processing,
and the {\em{net}\/}
power per unit area is about {\pdcol{0.002\,\Wmm}}.
The only way to get significant net power from the corn-to-ethanol
process is to ensure that all co-products are exploited;
including the energy in the co-products,\index{bioethanol!co-products} the
{net}
power per unit area is about {\pdcol{0.05\,\Wmm}}.\nlabel{CornUS}
% \subsection{Corn-growing in the USA -- details}
% Energy-related inputs to grow corn in the USA
% The main research result for
% bioethanol is that for ethanol to break even,
% it is essential to make use of coproducts
%
\margintab{
\begin{tabular}{ll} \toprule
\multicolumn{2}{r}{\ind{energy density}\index{calorific value}} \\
\multicolumn{2}{r}{(kWh/kg)} \\
% Calorific value (MJ/kg)
\midrule
%%%%%%%%%%%%%%%%%%%%%%%%%%% range midpoint
\ind{softwood} &\\
\,\,\,\, -- air dried & 4.4 \\% 14--18 16 \\
\index{wood}% &\\
\,\,\,\, -- oven dried & 5.5 \\% 17--23 20 \\
\ind{hardwood} &\\
\,\,\,\, -- air dried & 3.75 \\% 13--14 13.5 \\
% &
\,\,\,\, -- oven dried & 5.0 \\% 17--19 18 \\
{white office paper} & 4.0 \\
{glossy \ind{paper}} & 4.1 \\
{\ind{newspaper}} & 4.9\\
{\ind{cardboard}} & 4.5 \\ \midrule
{\ind{coal}} & 8 \\% 9.5GJ/t(wet)
\midrule
% Domestic wood & 2.8\\ % 2.778\\
% Industrial wood & 3.3\\ % 3.306\\
straw & 4.2\\ % 4.167\\
poultry litter & 2.4\\ % 2.445\\
general indust'l waste & 4.4\\ % 4.445\\
hospital waste & 3.9\\ % 3.889\\
{\index{municipal solid waste}}municipal solid waste & 2.6\\ % 2.639\\
refuse-derived waste & 5.1\\ % 5.139\\
tyres & 8.9\\ % 8.890\\
\bottomrule
\end{tabular}
%% see also
%% http://books.nap.edu/openbook.php?isbn=0309057450&page=54
% }{
\caption[a]{Calorific value of wood\index{wood}\index{trees}\index{data!wood}
and similar things.\index{calorific value!wood}\index{data!calorific values}
Sources: \cite{yaros,aysen}, Digest of UK Energy Statistics 2005.}
\label{pWoodTable}
\vspace*{13pt}
\lowres{\epsfxsize=53mm\epsfbox{../../images/WoodCS.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/WoodC.jpg.eps}}
}
\subsection{Cellulosic ethanol from switchgrass}
{Cellulosic ethanol} -- the wonderful ``next generation'' biofuel?\index{cellulosic ethanol}\index{biofuel!cellulosic ethanol}
% I've already asserted that the highest power density that
% any plants could achieve in Europe is 0.5\,\Wmm.
% Would you like to check this against the
% switchgrass literature?
%Schmer et al. (http://www.pnas.org/cgi/content/full/105/2/464) recently
%reported a "Net energy of cellulosic ethanol from switchgrass" of 60
%GJ/ha/y or 540% more renewable than nonrenewable energy^ consumed. This
%corresponds to 1.67 kWh/m2/y.
\citet{Schmer} found that the net energy yield of
\ind{switchgrass} grown over five years on
marginal cropland on 10 farms in the midcontinental US
% Annual biomass yields of established fields averaged 5.2 -11.1 Mg·ha%G–%@1 with a resulting average estimated net energy yield (NEY) of 60 GJ·ha%G–%@1·y%G–%@1.
was 60\,GJ per hectare per year,
which is \pdcol{0.2\,\Wmm}. ``This is a baseline study that represents the
genetic material and agronomic technology available for switchgrass
production in 2000 and 2001, when the fields were planted. Improved
genetics and agronomics may further enhance energy sustainability and
biofuel yield of \ind{switchgrass}.''\nlabel{RisoBio}
\subsection{Jatropha also
has low power per unit area }
% on radio 4 they said 1500 l per ha per year in India
% Tue 26/8/08
% further notes in biodiesel
% Jatropha: 175 US gal/acre (164 cubic m per square km)
% 175 US gallons per acre per year in litres per hectare per year
% 1600 litres per hectare per year
Jatropha is an oil-bearing crop that
grows best in dry tropical\index{jatropha}\index{biofuel!jatropha}
regions (300--1000\,mm rain per year).
It likes temperatures 20--28\degreesC\@.
% after one or two years of plant growth?
The projected yield in hot countries on good land is
1600 litres of biodiesel per hectare per year.
% 175 US gal biodiesel per acre per year
% (164 cubic m per square km)
That's a power per unit area of 0.18\,\Wmm.
% 0.183567
% Wikipedia says 1900\,litres per hectare per year.
% http://environmental.scum.org/biofuel/jatropha/
% It is hard to find successful examples of Jatropha cultivation on a plantation scale.
On wasteland, the yield
is 583 litres per hectare per year.\label{pNailJatropha}
That's
0.065\,\Wmm.
% Francis et al 2005:
% they project 10 million ha
% could produce 5 million tons
% biodiesel per year.
%% Diesel fuel has an
% energy density of 1058 kBtu/cu.ft.
% Biodiesel has an energy density of 950 kBtu/cu.ft
% DERV 11 kWh/l and 9.83 kWh/l Biodiesel
% DERV density is 0.84 biodiesel is 0.88
% 5e9 kg/10e6 ha/1 year / (0.88 g/cm**3 ) * 9.83 kWh/l in W/m**2
% 0.063716
% 175 US gal/acre / year * 9.83 kWh/l in W/m**2
%% (583 ((l / ha) / year)) * 9.83 (kWh / l) = 0.0653777368 W / (m ** 2)
% They also project \COO\ sequestration
% of 2.29\,t per ha.
%% they say 2.5 t per ha per year of biomass of which carbon is 0.25
% Source: \cite{FrancisJatropha}
% % cited in
%; sounds like there are many niggles.
If
% the niggles are sorted out
people decided to use 10\% of Africa to generate
0.065\,\Wmm, and shared this power between six billion people, what
would we all get?
% Africa 30065000 sq km
% 0.1 * 30065000 sq km * 0.065 W / ( sq m ) / 6e9
% 0.2TW.
% 32\,W per person; 0.7817
\OliveGreen{0.8\,kWh/d/p}.
% and 700 Mt CO2 capture per year
% The paper discussed 10 M ha of India 3287590 sq km; that is 3%.
% What is World oil consumption? World power is 15TW That is 60 kWh/d/p.
% Oil - Consumption: 82.59 million bbl/day
% https://www.cia.gov/library/publications/the-world-factbook/rankorder/2174rank.html
% 80e6 barrels per day * 1700 kWh per barrel / 6e9 in kWh per day
% 80e6 * 1700 / 6e9 kWh per day
For comparison, \ind{world oil consumption}\index{oil consumption, world}\index{data!oil consumption}
is 80 million barrels per day, which,
shared between six billion people, is
\Red{23\,kWh/d/p}.
So even if {\em{all}\/} of Africa were covered with jatropha
plantations, the power produced would be only one third of
world oil consumption.
\subsection{What about algae?}
Algae are just plants, so everything I've said
so far applies to algae. Slimy underwater plants\index{algae}
are no more efficient at photosynthesis than
their terrestrial cousins.
But there is one trick that
I haven't discussed, which is standard practice
in the algae-to-biodiesel community:
% researching the potential
% of algae for biodiesel production:
they grow their algae in water heavily enriched with
carbon dioxide, which might be collected from power stations
or other industrial facilities.
It takes much less effort for plants to photosynthesize
if the carbon dioxide has already been concentrated for them.
In a sunny spot in America, in
ponds fed with concentrated \COO\ (concentrated to 10\%),
Ron Putt of Auburn University
says that
algae can grow at 30\,g per square metre per day,
producing
% TODO: MJB *** says that I should add more connecting words explaining what
% these numbers are, how the calculation runs.
% see algae.tex
% 300 kg per ha per day
% 100\,litres of biodiesel per hectare per day.
0.01 litres of biodiesel per square metre per day.\nlabel{pPutt}
% \cite{PuttAlgae} done
% 100\,litres of biodiesel per hectare per day.
% Assuming biodiesel has 9.8 kWh/l;
This corresponds to a power per unit pond area of
\pdcol{4\,\Wmm} -- similar to the Bavaria photovoltaic farm.
% 4.2
If you wanted to drive a typical car
(doing 12\,\km\ \per\ \litre)
a distance of 50\,km per day, then you'd
need \areacolor{420 square metres} of algae-ponds just\index{biodiesel!from algae}
to power your car; for comparison, the area of the
UK per person is 4000 square metres, of which 69\,m$^2$ is water (\figref{landareas}).
Please don't forget that it's essential to feed these ponds with concentrated
carbon dioxide.
% http://www.berr.gov.uk/energy/sources/sustainable/carbon-abatement-tech/ccs/page42320.html
So this technology would be limited both by
land area -- how much of the UK we could turn into
algal ponds -- and by the availability of concentrated \COO,
the capture of which would have an energy cost (a
topic discussed in Chapters \ref{ch.sff} and \ref{ch.lastthing}).
% we'll come back to later).
% power stations
% 40 MtC per year equiv to 147 Mt COO per year - at 85%,
% get 125 Mt COO per year
Let's check the limit
imposed by the concentrated \COO\@.
To grow 30\,g of algae per m$^2$ per day
would require at least
60\,g of \COO\ per m$^2$ per day (because the \COO\ molecule has more mass per carbon
atom than the molecules in algae).
If all the \COO\ from all UK power stations were captured
(roughly 2$\dfrac{1}{2}$ \tonnes\ per year per person),
it could service
% 14 thousand square kilometres
% . That's
\areacolor{230 square metres} per person of
the algal ponds described above
-- roughly 6\% of the country.
% 150e6 tonnes per year / (30 grams per day per
% metre) in metres
% 1.4e10 square metres
% 1.4e4 square kilometres
% 14 thousand square kilometres
% 1.4e10 square metres / 60e6 = 233
% at 233mm per person and 4.2W/mm you'd get 980W per person
This area would deliver biodiesel with a power
%% cf the power of coal in the UK which is 11 kWh/d/p (electric).
of 24\,kWh per day per person, assuming that the numbers
for sunny America apply here.
% see solarnotes for more criticism
A plausible vision? Perhaps on one tenth of that scale?
I'll leave it to you to decide.
\subsection{What about algae in the sea?}
Remember what I just said: the algae-to-biodiesel\index{biofuel!from algae}
% community
posse always feed their algae concentrated \COO\@.\index{algae!biofuel}
If you're going out to sea, presumably pumping \COO\ into it
won't be an option. And without the concentrated \COO, the
productivity of algae drops 100-fold.
For algae in the sea to make a difference,
a country-sized harvesting area in the sea would be required.
% more on algae for power plants - blue-green
% http://www.sciencedaily.com/videos/2007/0407-possible_fix_for_global_warming.htm
\subsection{What about algae that produce hydrogen?}
Trying to get \ind{slime} to produce hydrogen in sunlight is a smart
idea because it cuts out a load of chemical steps\index{hydrogen!from algae}
normally performed by carbohydrate-producing\index{algae!hydrogen}
plants. Every chemical step reduces efficiency
a little. Hydrogen\index{hydrogen} can be produced
directly by the photosynthetic\index{photosynthesis} system,
right at step one.
% -- wippididoo! Of course, all we need
% \cite{AmosAlgae}
% to do is embrace the miraculous mystery of hydrogen.
% Let's find some numbers.
A research study from the
\ind{National Renewable Energy Laboratory} in \ind{Colorado}
predicted that a reactor filled with
genetically-\index{genetic modification}modified green \ind{algae},\index{green algae}
covering an area of
11 hectares in the \ind{Arizona} desert,
% Phoenix Arizona
%Table 2 shows the capital cost breakdown for the 300 kg/d stand-alone system with 110,000 m2
%of pond area, 0.2 g/L cell concentration, a truncated antennae mutant, 10 cm pond depth, and a
%$10/m2 bio-reactor cost for a site in Phoenix, Arizona.
could produce 300\,kg of hydrogen per day.\nlabel{GMAlgae}
% hydrogen contains 39kWh per kg
Hydrogen contains 39\,kWh per kg, so
this algae-to-hydrogen facility would
deliver a power per unit area of
% 11700 kWh per day / 11 hectares in W per square metre
% (11 700 (kWh per day)) / (11 hectares) = 4.43181818 W per (square meter)
4.4\,\Wmm.
% actually with a pipeline (no storage) they could deliver more
% 446 kg/d .
% What are the energy costs of running this facility?
% sotrage and compression are expensive.
% Electricity cost would be 11+6+16c per kg, which is 33c per kg
% Elec Cost per day: 300 * 0.33 = 100$ per day
% Elec Cost per kWh: (33c/kg) / (39kWh/kg) = 0.84c per kWh
% assume elec price 5c per kWh when he wrote. YES. CONFIRMED by him.
% that means 17% of energy required to run the place.
Taking into account the estimated electricity required to
run the facility,
the net power delivered would be reduced to \pdcol{3.6\,\Wmm}.
That strikes me as still quite a promising number -- compare it
with the Bavarian solar photovoltaic farm, for example (\pdcol{5\,\Wmm}).
% , whose power per unit area was \pdcol{5\,\Wmm}.
% http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_a.html
% see _biomass.tex for further notes and pointers
\section{Food for humans or other animals}
Grain crops\index{grain crops}\index{crops}
such as \ind{wheat}, \ind{oats}, \ind{barley}, and \ind{corn}
have an energy density of
% 13.9\,GJ/t (Wet).
about 4\,kWh per kg.
% 3.86.
% 13.9e9 * 7.7 / 1e4 / 365.25/24/3600
% ans = 0.33916
In the UK, wheat yields of 7.7 \tonnes\ per hectare per year are typical.
If the wheat is eaten by an animal, the power per unit area of this process is 0.34\,\Wmm.
If 2800\,m$^2$ per person of Britain (that's all agricultural land) were devoted to the growth of crops like these,
the chemical energy generated would be about \OliveGreen{24\,kWh/d per person}.
% Wheat to bioethanol:
% 1\,t wheat makes 336\,l.
% (What energy inputs required?)
% 21.1e6 J/l * 7.7e3kg/ha/year * 0.336l/kg in W/sq m
% That's 0.17\,\Wmm, not accounting for energy inputs required.
% 0.173
\section{Incineration of agricultural by-products}% as a coal substitute}
% On the other hand, maybe I should
% include farming by-products such as straw.
%
We found a moment ago that
the power per unit area of a biomass power station burning
the best energy crops is $0.2\,\Wmm$.
% {eqBIOMASS}
If instead we grow crops for food, and put the left-overs that we don't eat
into a power station -- or if we feed the food to chickens\index{chicken poo}
and put the left-overs that come out of the chickens' back ends
into a power station -- what power could be delivered per unit
area of farmland?
Let's make a rough guess, then take a look at some real data.
For a wild guess,
let's imagine that by-products are harvested
from half of the area of Britain (2000\,m$^2$ per person) and trucked to power stations,
and that general agricultural
by-products deliver 10\% as much power per unit area
as the best energy crops: $0.02\,\Wmm$.
Multiplying this by 2000\,m$^2$
% (half the area per person)
we get
\OliveGreen{$1\,\kWh$ per day per person}.
Have I been unfair to agricultural garbage in making this
wild guess?
We can re-estimate the plausible production from
agricultural left-overs by scaling up
the prototype \ind{straw-burning power station} at Elean in East
Anglia.\nlabel{pElean}
Elean's power output is 36\,MW, and it uses
200\,000 {\tonne}s per year from land located within a 50-mile radius.
If we assume this density can be replicated across the whole country,
the Elean model offers
% 36e6W/ pi / (50 * 1500 )**2 m**2
% pr 36e6/ pi / (50.0 * 1500 )**2
% (the mass rate is 10 grammes per square metre per year, btw)
0.002\,W/m$^2$.
At 4000\,m$^2$ per person, that's 8\,W per person, or \OliveGreen{0.2\,kWh/day per person}.
% If power stations like Elean
% could be packed five times more densely
%% 's power output were five times
%% greater,
% our calculation would have recovered the 1\,kWh per day
% of my wild guess.
Let's calculate this another way.
\index{data!straw production}UK
straw production is 10 million tons per year, or 0.46\,kg per day per person.
At 4.2\,kWh per kg, this straw has a chemical energy of 2\,kWh per day per person.
% elean corresponds to 1.57 kWh per kg
% ((36 MW) * (1 year)) / (200 000 tonnes) = 1.578 kWh per kg
If all the straw were burned in 30\%-efficient power stations -- a proposal that wouldn't
go down well with farm animals, who have other uses for straw -- the electricity
generated would be \OliveGreen{0.6\,kWh/d per person}.
% 0.575
\subsection{Landfill methane gas}
At present, much of the methane gas leaking out
of rubbish tips comes from biological
materials, especially waste food.
So, as long as we keep throwing away things like food
and \ind{newspaper}s, \ind{landfill gas} is a sustainable
energy source -- plus, burning that \ind{methane} might be
a good idea from a climate-change perspective, since
methane is a stronger greenhouse-gas than \COO\@.
A landfill site receiving 7.5\,million {\tonne}s of household waste
per year can generate 50\,000\,m$^3$ per hour of methane.\nlabel{pLandf}
%% See Clarks energy for details of the portable power stations
%% used at these sites -- drive-up power station plugs into the local
%% electricity grid.
In 1994,\index{methane}\index{natural gas}\index{gas!methane}\index{gas!landfill}\index{landfill gas}
landfill methane emissions were estimated to be
% 1.93Mt per year source Aitchison
% 0.09\,kg per person per day.
0.05\,m$^3$ per person per day,
% 0.46* 4.2e6 * 1e3 / 365.25 / 60e6 / 1.819
% ans = 0.048466
which has a chemical energy of 0.5\,kWh/d per person,
and would generate \OliveGreen{0.2\,\kWhe/d per person}, if it were
all converted to
electricity with 40\% efficiency.
Landfill gas emissions are declining because of changes in
legislation, and are now roughly 50\% lower.
% Sanity check this: if 400\,kg per year, \ie, 1\,kg per day, were
% same energy content as fossil fuel (it's not) then that would be
% 9\,kWh/d.
%% this doc gives very detailed charts of landfill production,
%% and no summary
%% http://www.ref.org.uk/images/pdfs/3.landfill.gas.pdf
%%%%%%%%%%??????????????? ***
% http://www.wasteresearch.co.uk/ade/efw/gas.htm
%emissions of landfill gas for the year 2000 are likely to be in the order of 660,000 t/y (K A Brown et. al.).
%calorific value of landfill gas is 37GJ/t.
% 660000 * 37GJ / year / 60e6 in kWh/day
% 0.309535853 kWh / day
% 0.123814341 kWh / day
% http://www.gcse.com/energy/landfill_gas_methane.htm
%This could generate around 6.75 TWh (cf. kWh) of electricity: enough for 1.6 million homes!
%6.75e9/60e6 / 365
%that's 0.31kWh/d/p
% (``from 40 million tonnes of waste ie 1.8kg per day per person. That's wrong, too big!
% In 1990, 2Mt per year of landfill methane. 120Mt per year of new waste arrives.
% Maximum rate of emission of landfill methane is 1115g/m**2/day
% turn this into Wmm
%
% the total amount of methane emitted by UK landfills is estimated to be around 500 Kt/a
% Author Alan Rosevear, UK Representative on Methane to Markets Landfill Gas Sub-Committee, May 2005.
% http://www.methanetomarkets.org/resources/landfills/docs/uk_lf_profile.pdf
% unclear which heat value to use.
% there is 600MW of capacity with avg output of 400MW output will drop to one third in 2020
% Anaerobic digester: yield from one tonne of food (23% solid, 77% water)
% is about 100 m**3, with energy value 21-28 MJ/mmm. And
% 20-50% of this energy needed to run the plant!
% Net energy produced by AD is roughly 75-150 kWh per tonne.
% source:
% http://www.waste.nl/content/download/472/3779/file/WB89-InfoSheet(Anaerobic%20Digestion).pdf
% http://www.waste.nl/content/download/472/3779/file/WB89-InfoSheet(Anaerobic Digestion).pdf
\subsection{Burning household waste}
% Some numbers:
% 1 t waste per household per year
\ind{SELCHP} (``South East London Combined Heat and Power'') [\myurlb{www.selchp.com}{http://www.selchp.com/}]
is a 35\,MW power station that is paid to burn
\marginfig{
%\begin{figure}\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
{\epsfysize=53mm\epsfbox{../../images/selchp/outside.eps}}%
\\
{\epsfxsize=53mm\epsfbox{../../images/selchp/inside.eps}}%
\\
\end{tabular}
\end{center}
\caption[a]{\ind{SELCHP} -- your trash is their business.
% They are {{paid}} to take waste (\pounds160 per ton), {\em{and}\/} they
% are paid for the electricity they generate from it (roughly \pounds 32 per MWh).
% MWhe
}
}%
420\,kt per year of black-bag waste from
%% Lewisham, Greenwich, Westminster and Bromley
the London area.\label{pSELCHPapp}
% They are {\em{paid}\/} \pounds160 per ton of waste.
They burn the waste as a whole, without sorting.
After burning, ferrous metals are removed for recycling, hazardous wastes
are filtered out and sent to a special landfill site, and the
remaining ash is sent for reprocessing into recycled material for
road building or construction use.
% Bottom Ash (around 110,000 {\tonne}s per
%> year) is separated into ferrous metals, nonferrous metals, aggregate
%> and finally useless waste that ends up in landfill (around 5% of the
%> total input to the plant goes this way).
%
The calorific value of the waste is
% 9000\,kJ/kg (2.5\,kWh/kg),
2.5\,kWh/kg,\index{calorific value!waste}
and the thermal efficiency of the power station is about 21\%,
so each 1\,\kg\ of waste gets turned into 0.5\,kWh of electricity.
The carbon emissions are about 1000\,g\,\COO\ per \kWh.
%
% (this disagrees with:
% The plant takes 420,000 {\tonne}s of waste each year to produce 120,000
% MWh per year of electricity.
% 120,000 MWh/year would agree with 240\,000\,t per year.
% Perhaps they take less waste than their nameplate says.)
%
% I don't think they deliver any heat to anyone, so it's not actually
% a CHP facility, in spite of its name.
%
Of the 35\,MW generated, about 4\,MW is used by
the plant itself to run its machinery and filtering processes.
Scaling this idea up,
if every borough had one of these, and if everyone sent 1\,kg per day
of waste, then we'd get
\OliveGreen{0.5\,\kWhe\ per day per person} from waste incineration.
% \marginpar{\small Check this agrees with `5 plans'.}
This is similar to the figure estimated above for methane capture
at landfill sites. And remember, we can't have both.
More waste incineration means less methane gas leaking out of
landfill sites.
%
See \figref{fig.waste}, \pref{fig.waste}, and \figref{figMuniLandIncRec}, \pref{figMuniLandIncRec},
for further data on waste incineration.
\medskip
\medskip
\medskip
%\beginfullpagewidth
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pdWood}]
{\nqs{The power per unit area
of using willow, miscanthus, or poplar, for electricity is 0.2\,\Wmm.}}
Source:
% Writing about , etc, not traditional wood:
Select Committee on Science and Technology Minutes of Evidence --
Memorandum from the Biotechnology
\& Biological Sciences Research Council
[\myurlb{www.publications.parliament.uk/pa/ld200304/ldselect/ldsctech/126/4032413.htm}{http://www.publications.parliament.uk/pa/ld200304/ldselect/ldsctech/126/4032413.htm}].
``Typically a sustainable crop of 10 dry t/ha/y of woody biomass can be produced in Northern Europe. \ldots\
%%
Thus an area of 1\,km$^2$ will produce 1000 dry t/y --
enough for a power output 150\,kWe at low conversion efficiencies or 300\,kWe at high conversion efficiencies.''
This means 0.15--0.3\,\Wemm.
% (electric).)
% This is more useful.
See also
\cite{Layzell},
\tinyurl{3ap7lc}{http://www.biocap.ca/files/Ont_bioenergy_OPA_Feb23_final.pdf}.
\item[\npageref{pRape}]
{\nqs{Oilseed rape.}}
Sources: \cite{BayerCropSci}, \cite{biofuels08},
\myurlb{www.defra.gov.uk}{http://www.defra.gov.uk/}.
\item[\npageref{pSugarB}]
{\nqs{Sugar beet.}} Source:
\myurlb{statistics.defra.gov.uk/esg/default.asp}{http://statistics.defra.gov.uk/esg/default.asp}
\item[\npageref{CornUS}]
{\nqs{Bioethanol from corn.}} Source:
\citet{CornEthanolEnergyBalance}.
\item[\npageref{RisoBio}]
{\nqs{Bioethanol from cellulose.}} See also \cite{RisoBiofuels}.
\item[\npageref{pNailJatropha}]
{\nqs{Jatropha.}}
Sources: \cite{FrancisJatropha}, \cite{jatropha}.
\item[\npageref{pPutt}]
{\nqs{
In America,
\amarginfignocaption{t}{
\begin{center}
{\epsfxsize=45mm\epsfbox{../../images/sunflowers.eps}}%
\end{center}
\label{Banksy}
}%
in ponds fed with concentrated \COO,
algae can grow at 30\,grams per square metre per day,
producing
0.01 litres of biodiesel per square metre per day}.}
Source: \citet{PuttAlgae}.
This calculation has ignored the energy cost
of running the algae ponds and processing the algae
into biodiesel.
% The paper
Putt
% \citet{PuttAlgae}
describes the energy balance of a proposed design for a
100-acre algae farm, powered by methane
from an animal litter digester.
% accrding to the paper the power cost would be
% 2600 kW for a 100 acre farm, for running the ponds and
% drying.
% 2600 kW / (100 acres) in W
% (2 600 kW) / (100 acres) = 6.42473992 W / (square meter)
The farm described would in fact produce
less power than the methane power input.
The 100-acre farm would use 2600\,kW of methane,
which corresponds to an input power density of 6.4\,\Wmm.
To recap, the power density of the output, in the
form of biodiesel, would be just 4.2\,\Wmm.
All proposals to make biofuels should be
approached with a critical eye!
\item[\npageref{GMAlgae}]
{\nqs{
A research study from the
{National Renewable Energy Laboratory}
predicted that genetically-\index{genetic modification}modified green \ind{algae},\index{green algae}
covering an area of
11\,hectares,
could produce 300\,kg of hydrogen per day.
}}
Source: \citet{AmosAlgae}.
\item[\npageref{pElean}] {\nqs{Elean power station.}}
% \subsection{Elean power station}
Source: Government White Paper (2003).
% ourenergyfuture.pdf
\ind{Elean Power Station} (36\,MW) --
the UK's first {straw-fired power plant}.\index{straw}
{\nqs{Straw production:}}
\myurlb{www.biomassenergycentre.org.uk}{http://www.biomassenergycentre.org.uk/}.
\item[\npageref{pLandf}]
{\nqs{Landfill gas.}}
Sources: Matthew Chester, City University, London, personal communication;
\citet{MeadowsLandfillMethane}, \cite{Aitchison96};
Alan Rosevear, UK Representative on Methane to Markets Landfill Gas Sub-Committee,
May 2005
% [\myurlb{www.methanetomarkets.org/resources/landfills/docs/uk_lf_profile.pdf}%
\tinyurl{4hamks}{http://www.methanetomarkets.org/resources/landfills/docs/uk_lf_profile.pdf}.
\end{notelist}
\normalsize
%\ENDfullpagewidth
\rset\chapter{\rcol{Heating II}}
\label{ch.heating2}
\amarginfignocaption{b}{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=53mm\epsfbox{../../images/BWBldgNYS.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/BWBldgNY.jpg.eps}} \\
\end{tabular}\label{Claire2}
\end{center}
%\caption[a]{ }
}
% \section{What determines your heating bill?}
A perfectly sealed and insulated building would
hold heat for ever and thus would need no heating.
The two dominant reasons why buildings lose heat are:\index{building!heat consumption}
\ben
\item
{\bf Conduction} --
heat flowing directly through walls, windows and doors;
\item
{\bf Ventilation} --
hot air trickling out through cracks, gaps, or deliberate ventilation
ducts.
\een
In the standard model for heat loss, both these heat flows
are proportional to the temperature difference between the
air inside and outside.
For a typical British house, conduction is the bigger
of the two losses, as we'll see.
\subsection{Conduction loss}
%\margintab{
The rate of conduction of heat through a wall, ceiling, floor, or window
is the product of three things: the area of
the wall, a measure of conductivity of the wall
known in the trade as the ``U-value'' or \ind{thermal transmittance},
and the temperature difference --
\[
\mbox{power loss} =
\mbox{area}
\times
U
\times
\mbox{temperature difference} .
\]
The \ind{U-value} is usually measured in
\Wmm/K\@. (One \ind{kelvin}
(1\,K) is the same as one degree \ind{Celsius} (1\degreeC).)
Bigger U-values mean bigger losses of power.
The thicker a wall is, the smaller its U-value.
%Single-glazed window
%5 \Wmm/K, while an unfilled cavity wall would be about
%1.4 \Wmm/K\@.
Double-glazing is about as good as a solid brick wall.
%% my new front door is going to be 1.8, and its glass will be 1.6.
(See \tabref{tab.Uv}.)
The U-values of objects that are ``in series,''
such as a wall and its inner lining, can be combined
in the same way that electrical
conductances combine:
\[
u_{\rm series\ combination} = 1\left/ \left( \frac{1}{u_1} + \frac{1}{u_2} \right)
\right. .
\]
There's a worked example using this rule
on page \pageref{pUseries}.
{%%%%%%%%%%%%%%%%%%%%%% troublesome
% put me BEFORE troublesome heating. diagram page % see AFTER
\renewcommand{\floatpagefraction}{0.8}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Ventilation loss}
To work out the heat required to warm up incoming cold air,
we need the heat capacity of air:
% The heat capacity of air per unit volume is
% 1\,kJ/kg/\ndegreeC $\times$ 1.2\,kg/m$^3 = 1.2\,\kJ/\m^3/\ndegreeC$.
$1.2\,\kJ/\m^3/$K\@.
In the building trade, it's conventional to
describe the power-losses caused by \ind{ventilation} of a space
as the product of
the number of changes $N$ of the air per hour,\index{air changes}
the volume $V$ of the space in cubic metres,
\margintab{
\begin{center}
% http://www.diydata.com/planning/ch_design/sizing.php
\begin{tabular}{lc} \toprule
kitchen & 2\\
bathroom & 2\\
lounge & 1\\
bedroom & 0.5 \\
\bottomrule
\end{tabular}
\end{center}
\caption[a]{Air changes\index{air changes}\index{ventilation}
per hour: typical values of $N$
for draught-proofed rooms.\index{draught proofing}
The worst draughty rooms might have $N=3$ air changes per hour.
% One cubic metre
The recommended minimum
rate of air exchange is between 0.5 and 1.0 air changes per hour,
providing adequate fresh air for human health, for safe combustion of fuels and to prevent
damage to the building fabric from excess moisture in the air (EST 2003).
}
}%
the heat capacity $C$, and the temperature difference $\Delta T$
\begin{table}\figuremargin{
\begin{tabular}{lrrr} \toprule
& \multicolumn{3}{c}{U-values (\Wmm/K)} \\ \cmidrule{2-4}
& old & modern & best \\
& \makebox[0in][r]{buildings} & standards & methods \\
\midrule
Walls & & 0.45--0.6 & 0.12 \\
% Single-glazed window & 5\,\Wmm/K\\
% Unfilled cavity wall & 1.4\,\Wmm/K \\
\ \ solid masonry wall & 2.4 \\
% http://www.diydata.com/information/u_values/u_values.php
\ \ outer wall: 9\,inch solid brick & 2.2\\%.
\ \ 11\,in brick-block cavity wall, unfilled & 1.0\\%.
\ \ 11\,in brick-block cavity wall, insulated & 0.6\\%.
%%
\midrule
Floors & & 0.45 & 0.14 \\
\ \ suspended timber floor& 0.7\\%.
\ \ solid concrete floor & 0.8\\%.
\midrule
Roofs & & 0.25 & 0.12 \\
\ \ flat roof with 25\,mm insulation& 0.9\\%.
\ \ pitched roof with 100mm insulation & 0.3\\%.
\midrule
Windows & & & 1.5 \\
\ \ single-glazed & 5.0\\%.
\ \ double-glazed & 2.9\\%.
\ \ double-glazed, 20\,mm gap & 1.7\\%.
\ \ triple-glazed & 0.7--0.9\\%. sources: http://www.building.co.uk/story.asp?sectioncode=482&storycode=3110977&c=3
%% + Sustainable Solar Housing By Robert Hastings, Maria Wall, International Energy Agency Solar Heating
%% my new front door is going to be 1.8, and its glass will be 1.6.
\bottomrule
\end{tabular}}{
\caption[a]{U-values of walls, floors, roofs, and windows.}\label{tab.Uv}
%% Useful U-values:
}
\end{table}
%}
\begin{figure}
\figuremargin{%
\mbox{\epsfbox{metapost/heating.101}}
}{
\caption[a]{U-values required by British
and Swedish building regulations.\index{building!regulations}
}
\label{BuildingRegFig}
}
\end{figure}
%% /home/mackay/images/071201
between the inside and outside of the building.
% in appropriate units, which turns out to be $1/3$:
\beqan
\begin{tabular}{c} \mbox{power}\\
{(watts)} \\
\end{tabular}
&=& C \frac{N}{1\, \h} V (\m^3) \Delta T (\degreesK)\\
&=& (1.2\,\kJ/\m^3/\degreeK) \frac{N}{3600\, \s} V (\m^3)
\Delta T (\degreesK)
\\
&=&
%\ = \
\frac{1}{3} N V \Delta T .
\eeqan
\subsection{Energy loss and temperature demand (degree-days)}
% Again, the total energy lost is proportional to a
% property of the building times the
% temperature demand.
Since energy is power $\times$ time, you
can write the energy lost by {\em{conduction}\/} through an area
in a short duration as
\[
\mbox{energy loss} =
\leakcol{\mbox{area}
\times
U}
\times
(\Delta T \times \mbox{duration}) ,
\]
\index{convective heat loss rate}and the energy lost by {\em{ventilation}\/} as
\[
\leakcol{\frac{1}{3} N V} \times
(\Delta T\times \mbox{duration}).
\]
Both these energy losses have the form
\[
\leakcol{\mbox{Something}} \times (\Delta T\times \mbox{duration}),
\]
where the ``\leakcol{Something}'' is measured in watts per \ndegreeC\@.
As day turns to night, and seasons pass, the
temperature difference $\Delta T$ changes; we can think of a long period
as being chopped into lots of small durations, during each of which
the temperature difference is roughly constant.
From duration to duration, the temperature difference changes,
but the Somethings don't change.
When predicting a space's
total energy loss due to conduction and ventilation over a long period
we thus need to multiply two things:
\begin{enumerate}
\item
the sum of all the \leakcol{Somethings} (adding
\leakcol{$\mbox{area} \times U$}
for all walls, roofs, floors, doors, and windows,
and \leakcol{$\frac{1}{3} N V$} for the volume);
and
\item
the sum of all the
$\mbox{Temperature difference} \times \mbox{duration}$
factors (for all the durations).
\end{enumerate}
%% I got 15.5 1869.41 (explanation -- I use day averages, not half-hour)
%% made by daily.pl and gnudd
\begin{figure}[htbp]
\figuremargin{\small
\begin{center}
\begin{tabular}[b]{l}
\begin{tabular}[b]{ccc}
\raisebox{2cm}{(a)}&
\raisebox{2.653cm}{\makebox[0in][l]{\sf temperature (\ndegreesC)}}%
\mono%
{\epsfxsize=4in\epsfbox{../data/cambridge/mono/Cam2006Temp2020.eps}}%
{\epsfxsize=4in\epsfbox{../data/cambridge/Cam2006Temp2020.eps}}
\\
\raisebox{2cm}{(b)}&
\raisebox{2.653cm}{\makebox[0in][l]{\sf temperature (\ndegreesC)}}%
\mono%
{\epsfxsize=4in\epsfbox{../data/cambridge/mono/Cam2006Temp3017.eps}}%
{\epsfxsize=4in\epsfbox{../data/cambridge/Cam2006Temp3017.eps}}
\\
% \raisebox{2cm}{(c)}&\mbox{\epsfxsize=4in\epsfbox{../data/cambridge/Cam2006Temp3015.eps}} \\
\end{tabular}
\end{tabular}
\end{center}
}{
\caption[a]{The temperature demand
in Cambridge, 2006, visualized
as an area on a graph of daily average temperatures.
(a) Thermostat set to 20\degreesC, including
cooling in summer;
(b) winter thermostat set to 17\degreesC\@.
% ; (c) Winter thermostat set to 15\degreesC\@.
} \label{degreeday}
}
\end{figure}%
The first factor is a property of the building measured in
watts per \degreeC\@. I'll call this the {\sl\ind{leakiness}\/}
of the building.
%\[
% \mbox{Leakiness} = \sum
%\]
%
(This leakiness is sometimes called the building's
{\dem\ind{heat-loss coefficient}}.)
The second factor is a property of the weather; it's
often expressed as a number of ``\ind{degree-day}s,''
since temperature difference is measured in degrees, and
days are a convenient unit for thinking about durations.
For example, if your house interior is at 18\degreesC,
and the outside temperature is 8\degreesC\ for a week, then
we say that that week contributed
$10 \times 7= 70$ degree-days to the $(\Delta T
% \mbox{Temperature difference}
\times \mbox{duration})$ sum.
I'll call the sum of all the $(\Delta T
\times \mbox{duration})$ factors the {\dem{\ind{temperature demand}}\/} of a period.
\amarginfig{t}{\small
\begin{center}
\begin{tabular}[b]{l}
\raisebox{6.51cm}{\makebox[0in][l]{\sf\small \begin{tabular}{l}{temperature demand}\\{(degree-days per year)}\\ \end{tabular}}}%
\mono%
{\epsfxsize=50mm\epsfbox{../data/cambridge/mono/Cam2006dd.eps}}%
{\epsfxsize=50mm\epsfbox{../data/cambridge/Cam2006dd.eps}}
\\
\end{tabular}
\end{center}
\caption[a]{Temperature demand in Cambridge, in degree-days per year,
% for the year 2006 in Cambridge, in degree days,
as a function of thermostat setting (\degreesC).
Reducing the winter thermostat from 20\degreesC\ to
17\degreesC\ reduces the temperature demand of heating
by 30\%, from 3188 to 2265 degree-days.
Raising the summer thermostat from 20\degreesC\ to
23\degreesC\ reduces the temperature demand of cooling
by 82\%, from 91 to 16 degree-days.
}
\label{degreedayc}
}
\[
\mbox{energy lost } = \mbox{leakiness} \times \mbox{temperature demand}.
\]
We can reduce our energy loss by reducing
the leakiness of the building, or
by reducing
our temperature demand, or both.
The next two sections look more closely
at these two factors, using a house in Cambridge as a case-study.
There is a third factor we must also discuss.
The lost energy is replenished by the building's heating system,
and by other sources of energy such as the occupants,
their gadgets, their cookers, and the sun.
Focussing on the heating system,\index{heating!efficiency}
the energy {\em{delivered}\/} by the heating is not the same as the
energy {\em{consumed}\/} by the heating. They are related by
the {\dem\ind{coefficient of performance}\/} of the heating system.
\[
\mbox{energy consumed} =
\mbox{energy delivered} / \mbox{\ind{coefficient of performance}} .
\]
% For some simple heaters, such as electric bar fires,
% the coefficient of performance is 1.
For a \ind{condensing boiler} burning natural gas, for example,
the coefficient of performance
is 90\%, because 10\% of the energy is lost up the chimney.
To summarise, we can reduce the
energy consumption of a building in three ways:
\begin{enumerate}
\item
by reducing temperature demand;
\item
by reducing leakiness; or
\item
by increasing the coefficient of performance.
\end{enumerate}
%\[
%\mbox{energy lost } = \mbox{leakiness} \times \mbox{temperature demand}.
%\]
We now quantify the potential of these options.
% potential of each of these modifications.
(A fourth option -- increasing the building's
incidental heat gains, especially from the sun -- may also
be useful, but I won't address it here.)
\subsection{Temperature demand}
We can visualize the temperature demand nicely on a
graph of external temperature versus time (\figref{degreeday}).
For a building held at a temperature of 20\degreesC,
the total temperature
demand is the {\em{area}\/} between the
horizontal line at 20\degreesC\ and the external temperature.
In \figref{degreeday}a, we see that, for one year
in Cambridge, holding the
temperature at 20\degreesC\ year-round had
a temperature demand of
3188 degree-days of heating and
91 degree-days of cooling.
These pictures allow us easily to assess the effect of
turning down the thermostat and living without air-conditioning.
Turning the winter thermostat down to 17\degreesC,
the temperature demand for heating drops from
3188 degree-days to
2265 degree-days (\figref{degreeday}b), which corresponds
to a 30\% reduction in heating demand.
Turning the thermostat down to 15\degreesC\ reduces the temperature
demand from 3188 to 1748 degree days,
% (\figref{degreeday}c),
a 45\% reduction.
These calculations give us a ballpark indication of the
benefit of turning down thermostats, but will
give an exact prediction only if we take into account two details:
first, buildings naturally absorb energy from the sun, boosting the
inside above the outside temperature, even
\amarginfig{b}{
\begin{center}
\begin{tabular}{l}
\mono%
{\epsfxsize=50mm\epsfbox{../data/cambridge/mono/Cam2006ddd.eps}}%
{\epsfxsize=50mm\epsfbox{../data/cambridge/Cam2006ddd.eps}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{The temperature demand
in Cambridge, 2006, replotted in units of degree-days per day,
also known as degrees.
In these units, the temperature demand is just the average
of the temperature difference between inside and outside.
}
\label{degreedayd}
}%
%% gnudd
without any heating; and second, the occupants and their gadget companions
emit heat, so further cutting down the artificial heating requirements.
% The Carbon Trust suggest correcting
% The base temperature used to calculate temperature demand
% degree days
% in the UK is 15.5\degreesC\@.
%% http://www.carbontrust.co.uk/resource/degree_days/what_are.htm
%% double check their figures for 2006:
%% SouthEast pr 335+334+321+ 191+96+39+7+27+22+82+207+268 = 1929
%% EastAnglia pr 350+325+343+222+109+ 54+ 11+ 31+ 19+ 75+217+290 =2046
%% gnudd
The temperature demand of a location, as conventionally expressed
in \ind{degree-day}s, is a bit of an unwieldy thing. I find it hard to
remember numbers like ``3500\,degree-days.'' And \ind{academics}
may find
the degree-day a distressing unit, since they already have another
meaning for degree days (one involving dressing up in \ind{gown}s
and \ind{mortar board}s).
We can make this quantity more meaningful and perhaps easier
to work with by dividing it by 365, the number of days in the year,
obtaining the temperature demand in ``degree-days per day,''
or, if you prefer, in plain ``degrees.'' \Figref{degreedayd}
shows this replotted temperature demand.
Expressed this way, the temperature demand is simply the
{\em{average}\/} temperature difference between inside and outside.
The highlighted temperature demands are:
8.7\degreesC, for a thermostat setting of 20\degreesC;
6.2\degreesC, for a setting of 17\degreesC;
and 4.8\degreesC, for a setting of 15\degreesC\@.
\subsection{Leakiness -- example: my house}
\amarginfig{c}{
%\begin{figure}
%\figuremargin{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\mbox{\epsfxsize=53mm\epsfbox{../../images/HouseSnowS.eps}}}%
{\mbox{\epsfxsize=53mm\epsfbox{../../images/HouseSnow.jpg.eps}}} \\
\end{tabular}
\end{center}
%}{
\caption[a]{My house.}\label{fig.MyHo}
%% , yesterday.}
}%
% case study
My house is a three-bedroom semi-detached house built
about 1940 (\figref{fig.MyHo}). By 2006, its kitchen had been slightly extended,
and most of the windows were double-glazed. The front
door and back door were both still single-glazed.
My estimate of the leakiness in 2006 is built up as shown in
\tabref{tab.LeakiBreak}.
\begin{table}
\figuremargin{
\begin{tabular}{lrrr} \toprule
{\sc{Conductive leakiness}}
& area & U-value & leakiness \\
& (m$^2$) & (\Wmm$\!$/\ndegreeC) & (W$\!$/\ndegreeC) \\
\midrule
\multicolumn{4}{l}{Horizontal surfaces}\\%Floor and ceilings} \\
% \midrule
\ \ \ Pitched roof & 48 & {\modcol{0.6}} & 28.8\\
\ \ \ Flat roof & 1.6 & 3 & 4.8\\
\ \ \ Floor & 50 & 0.8 & 40 \\
\midrule
\multicolumn{4}{l}{Vertical surfaces}\\% Walls \\
%\midrule
\ \ \ Extension walls & 24.1 &0.6 & 14.5\\
\ \ \ Main walls & 50 &{\modcol{1}}&50 \\
\ \ \ Thin wall (5\inch) & 2 &3 & 6 \\
\ \ \ Single-glazed doors and windows & 7.35 &{\modcol{5}} & 36.7\\
\ \ \ Double-glazed windows & 17.8 &2.9& 51.6\\
\midrule
\multicolumn{3}{l}{Total conductive leakiness} & 232.4\\
\bottomrule
\end{tabular}
\begin{tabular}{lccr}\toprule
{\sc{Ventilation leakiness}}
%\\
% Space
& volume & $N$ & leakiness \\
& (m$^3$) & (air-changes per hour) & (W$\!$/\ndegreeC) \\ \midrule
\ Bedrooms & 80 & 0.5 & 13.3\\
\ Kitchen & 36 & 2 & 24 \\
\ Hall & 27 & {\modcol{3}} & 27 \\
\ Other rooms& 77& 1 & 25.7 \\
\midrule
\multicolumn{3}{l}{Total ventilation leakiness} & 90 \\
\bottomrule
\end{tabular}\smallskip
% total volume of house : 80+36+27+77 = 220
}{
\caption[a]{
Breakdown of my house's conductive leakiness, and its
ventilation leakiness, pre-2006.
I've treated the central wall of the semi-detached house as
a perfect insulating wall, but this may be wrong if the
gap between the adjacent houses is
actually well-ventilated.\smallskip
I've highlighted the parameters that I altered
after 2006, in modifications to be described shortly.
% argon is used because it has conductivity 0.67 x that of air (especially
% because of its low heat capacity)
\index{leakiness}\index{wall}\index{door}\index{window}\index{double glazing}\index{glazing}\index{U-value}
}\label{tab.LeakiBreak}
}
\end{table}
The total leakiness of the \ind{house} was 322\,\WC\ (or 7.7\,kWh/d/\ndegreeC),
with conductive leakiness accounting for 72\%
and ventilation leakiness for 28\% of the total.
The conductive \ind{leakiness} is roughly equally divided into three parts:
windows; walls; and floor and ceiling.
% pr 322 * 24 / 1000.0
% We can also express the leakiness as .
To compare the leakinesses of two buildings that have different
floor areas,\index{building!leakiness}\index{building!heat-loss parameter} we can
% One way of presenting the leakiness that allows one building to
% be compared with another is to
divide the leakiness
by the floor area; this gives the
{\dem\ind{heat-loss parameter}\/}
of the building, which is measured in W/\ndegreeC/m$^2$.
The \ind{heat-loss parameter} of this house (total floor area 88\,m$^2$)
is
\[
% 322 / 88
3.7\,\mbox{W/\ndegreeC/m$^2$}.
\]
Let's use these figures
% from the previous section
to estimate the house's daily energy consumption on a cold winter's day,
and year-round.
On a cold day, assuming an external temperature of $-1$\degreeC\ and
%Standard external temperature: $-1$\degree C\@.
%http://www.diydata.com/planning/ch_design/sizing.php
%Standard internal temperature: 16--21\degree C\@.
an internal temperature of 19\degreeC,
the temperature difference is $\Delta T = 20 \degreeC$.
If this difference is maintained for 6 hours per day
then the energy lost per day is
\[
322\,\W/\ndegreeC \times 120\,\mbox{degree-hours}
\simeq 39\,\kWh .
\]
If the temperature is maintained at 19\degreesC\ for 24 hours per day,
the energy lost per day is
\[
155 \,\kWh/\d.
\]
To get a year-round heat-loss figure, we can take the temperature demand
of Cambridge from \figref{degreedayc}.
With the thermostat at 19\degreesC, the temperature demand
in 2006 was 2866 degree-days.
The average rate of heat loss, if the house is always held
at 19\degreesC, is therefore:
\[
\mbox{7.7\,kWh/d/\ndegreeC} \times 2866\,\mbox{degree-days/y}
/ (\mbox{365\,days/y}) = 61\,\kWh/\d.
\]
Turning the thermostat down to 17\degreesC,
the average rate of heat loss drops to 48\,kWh/d.
Turning it up to a tropical 21\degreesC, the average rate of heat loss
is 75\,kWh/d.
%Background
%
%The model says losses on a cold winter day are about 37 kWh/d by
%conduction and about 13 kWh/d by ventilation/draughts.
\subsubsection{Effects of extra insulation}
During 2007, I made the following modifications to the house:
\ben
\item
Added \ind{cavity-wall insulation} (which was missing in the main walls of the house) -- \figref{fig.Cavit}.
\item
Increased the insulation in the roof.
\item
Added a new front door outside the old -- \figref{frontD}.
\item
Replaced the back door with a double-glazed one.
\item
Double-glazed the one window that was still single-glazed.
\een
%% TODO *** change order to match table (merge 4/5)
What's the predicted change in heat loss?
The total leakiness before the changes was 322\,\WC\@.
Adding cavity-wall insulation (new U-value 0.6) to the main walls reduces
the house's leakiness by 20\,\WC\@.
% their leakiness from 50 to 30\,\WC\@.
The improved loft insulation (new U-value 0.3) should reduce
the leakiness by 14\,\WC\@.
The glazing modifications (new U-value 1.6--1.8) should reduce the conductive
leakiness by 23\,\WC, and the ventilation
leakiness by something like 24\,\WC\@.
%% 51-27 -- kitchen and hall
%% 24+23+14+20
That's a total reduction in leakiness of 25\%,
% 81\,W/\ndegreeC,
from roughly 320 to 240\,W/\ndegreeC\ (7.7 to
6\,kWh/d/\ndegreeC).
\Tabref{tabPREDhr} shows the predicted savings from each of
the modifications.
The \ind{heat-loss parameter} of this house (total floor area 88\,m$^2$)
is thus hopefully reduced by about 25\%, from 3.7 to
$2.7\,\mbox{\WC/m$^2$}$. (This is a long way from the 1.1\,\WC/m$^2$
required of a ``sustainable'' house in the new building codes.)
% put me AFTER troublesome heating. diagram page % see BEFORE
% END \renewcommand{\floatpagefraction}{0.8}
}
\begin{table}[!b]
\figuremargin{
\begin{center}
\begin{tabular}{lp{3in}r} \toprule
--& Cavity-wall insulation (applicable to two-thirds of the wall area) & 4.8\,kWh/d\\
-- & Improved roof insulation & 3.5\,kWh/d \\
--& Reduction in conduction from double-glazing two
doors and one window & 1.9\,kWh/d \\
% 1.2 front, 0.7 kitchen
--& Ventilation reductions in hall and kitchen from improvements
to doors and windows & 2.9\,kWh/d \\
% 2.1 hall, 0.8 kitchen
\bottomrule
\end{tabular}
\end{center}
% see /home/mackay/sustainable/girton/myhouse/Uvalues.gnumeric
% and _heating.tex
}{
\caption[a]{
Break-down of the predicted reductions in heat loss from my house, on a cold winter day.
}\label{tabPREDhr}
}
\end{table}
It's frustratingly hard to make a really big dent in the
leakiness of an already-built house!
As we saw a moment ago,
a much easier way of achieving a big dent in heat loss
is to turn the thermostat down. Turning down from 20 to 17\degreesC\
gave a reduction in heat loss of 30\%.
%% I find that 16 is too low when wearing shorts and sitting still
%% for a long time. Though it is fine for getting up,
%% having breakfast, and leaving.
%%
Combining these two actions -- the physical modifications
and the turn\-ing-down of the thermostat -- this model predicts that
heat loss should be reduced by nearly 50\%.
% 47.5
Since some heat is generated in a house by
sunshine, gadgets, and humans,
the reduction in gas consumption
should be more than 50\%.
% Put Eden and Bending material here.
I made all these changes to my house
and monitored my meters every week.
I can confirm that my heating
bill indeed went down by more than 50\%.
% In fact, owing to my slow writing pace, I can tell you here and now:
As \figref{fig.gas0} showed, my gas consumption
has gone down from 40\,kWh/d to 13\,kWh/d -- a reduction of 67\%.
%% RHFriend heat pump numbers
%% Source LG website. S18AW.
%%efficiency 380% or 360%
%% ground-source heat pump
% 1m below ground, temp is almost constant, about 7-13C\@.
%% source: www.iceenergy.co.uk/
%% use heat pump from 7-13 to 50C, ok for underfloor heating (but not conventional
%% radiators)
%% efficiency would be 700%.
%% 80C radiators would be less efficient.
%% ``I am saving 75%''
%Estimated loss, when temperature difference is 20\degreesC:
%{\em what's missing here?}
\subsubsection{Leakiness reduction by internal wall-coverings}
Can you reduce your walls' leakiness by covering the {\em{inside}\/} of the
wall with \ind{insulation}?
The answer is yes, but there may be two complications.
First, the thickness of internal covering is bigger than you might expect.
To transform an existing nine-inch solid brick wall (U-value 2.2\,\Wmm/K)
into a decent 0.30\,\Wmm/K wall, roughly 6\,cm of insulated lining board
is required
\tinyurl{65h3cb}{http://www.dorset-technical-committee.org.uk/reports/U-values-of-elements-Sept-2006.pdf}.
Second, \ind{condensation} may form on the hidden surface of
such internal \ind{insulation} layers, leading to \ind{damp} problems.
If you're not looking for such a big reduction in wall leakiness,
you can get by with a thinner internal covering.
For example, you can buy 1.8-cm-thick
% thermaline REVEAL phenolic foam and wallboard
insulated wallboards with a U-value of 1.7\,\Wmm/K\@.
With these over the existing wall, the
U-value would be reduced from 2.2\,\Wmm/K
to:\label{pUseries}
\[
1 \left/ \left( \frac{1}{2.2} + \frac{1}{1.7} \right) \right. \: \simeq \: 1\,\Wmm/K.
% 0.95
\]
Definitely a worthwhile reduction.
% see also Celotex tuff-R GA3000 and Celotex T-Break TB3000
\section{Air-exchange}
Once a building is really well insulated, the principal loss of heat will be
through \ind{ventilation} (\ind{air changes}) rather than through conduction.
The heat loss through ventilation can be reduced by transferring the heat
from the outgoing air to the incoming air.
Remarkably, a great deal of this heat can indeed be transferred without
any additional energy being required.
The trick is to use a \ind{nose},\index{nostril} as discovered by natural selection.
A nose warms incoming air by cooling down outgoing air.
There's a temperature gradient along the nose;
the walls of a nose are coldest near the nostrils.
% losest to the external temperature
\index{counter-current heat exchange}The longer your nose, the better it works as
a counter-current heat exchanger.
% Noses also use the same principle to reduce water-loss.
In nature's noses, the direction of the air-flow usually alternates.
Another way to organize a nose is to have two air-passages, one
for in-flow and one for out-flow, separate from the point of view of air,
but tightly coupled with each other so that heat can
easily flow between the two passages. This is how the noses work in buildings.
It's conventional to call these noses heat-exchangers.\index{heat exchanger}
{%%%%%%%%%%%%%%%%%%%%%% troublesome
% put me BEFORE troublesome heating. diagram page % see AFTER
\renewcommand{\floatpagefraction}{0.8}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%*** could move the house description into the margin; need to get a photo;
%% could put the heat exchang photo here.
\section{An energy-efficient house}
In 1984,
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/Serrekunda.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{The \ind{Heatkeeper} Serrekunda.
}\label{Heatkeeper}
}%
an energy consultant, Alan Foster, built
an energy-efficient house near Cambridge; he kindly gave me
his thorough measurements.
% Serrekunda Heatkeeper
The house is a timber-framed\index{building!Heatkeeper}
bungalow based on a Scandinavian ``\ind{Heatkeeper} Serrekunda''
design (\figref{Heatkeeper}),
with a floor area of 140\,m$^2$,
composed of three bedrooms, a study, two bathrooms,
a living room, a kitchen, and a lobby.
% the garage not included.
The wooden outside walls were
supplied in kit form by a Scottish company, and the main parts
of the house took only a few days to build.
% James Walker Ltd, cost was 25K pounds
% Timber
% Wall area 90.51, window area 31.69
% roof area 137.
% Venitlated volume 300 m**3, 40% loss in heat exchanger 0.38 air changes
% per hour. Specific heat 0.33. (gives 296 watts at 20C temp diff)
The walls are 30\,cm thick and have a U-value of 0.28\,\Wmm/\ndegreeC.
From the inside out, they consist of 13\,mm of plasterboard, 27\,mm
airspace, a vapour barrier, 8\,mm of plywood, 90\,mm of rockwool, 12\,mm
of bitumen-impregnated fibreboard, 50\,mm cavity, and 103\,mm of brick.
% The external bricks are not load-bearing.
% These walls
The ceiling construction is similar with 100--200\,mm of rockwool insulation.
The ceiling has a U-value of 0.27\,\Wmm/\ndegreeC, and the floor,
0.22\,\Wmm/\ndegreeC\@.
% calculated U values 0.168 round edges and 0.285 in centre.
% Floor = 50mm styrofoam with 40mm bearers supporting 19mm chipboard flooring.
% above a standard concrete floor.
The windows are double-glazed (U-value 2\,\Wmm/\ndegreeC),
with the inner panes' outer surfaces
specially coated to reduce radiation.
The windows are arranged to give substantial solar gain,
contributing about 30\% of the house's space-heating.
% In summer the orientation
% of the windows can be reversed to reduce solar gain.
% hermetically
The house is well sealed, every door and window lined with
neoprene gaskets.
The house is heated by warm air pumped through floor grilles;
in winter, pumps remove used air from several rooms, exhausting
it to the outside, and they take in air from the loft space.
The incoming air and outgoing air pass through a heat exchanger
(\figref{HeatExchanger}),
\amarginfig{t}{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=40mm\epsfbox{../../images/HeatEx.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{The \ind{Heatkeeper}'s heat-exchanger.
}\label{HeatExchanger}
}%
which saves 60\% of the heat in the extracted air.
The heat exchanger is a passive device, using no
energy: it's like a big metal nose, warming the incoming
air with the outgoing air.
On a cold winter's day, the outside air temperature was $-8$\degreesC,
the temperature in the loft's air intake was 0\degreesC, and the air
coming out of the heat exchanger was at $+8$\degreesC\@.
For the first decade,
the heat was supplied entirely by electric heaters, heating
a 150-gallon heat store during the overnight economy period.
% using four 3kW immersion heaters, to 92C
More recently a gas supply was brought to the house, and the space
heating is now obtained from a condensing boiler.
% Domestic hot water: big 56 gallon cylinder, electric heated to
% 60C overnight.
% for Dom HW, 13297 kWh in 8.333 y which is 1595 per y
The heat loss through conduction and ventilation is
% 3.51 kW * 24 / 20 h/degree-day
% 4.2\,kWh/degree-day.
4.2\,kWh/d/\ndegreeC\@.
The {\dem\ind{heat loss parameter}\/}
(the leakiness per square metre
of floor area)
is 1.25\,\Wmm/\ndegreeC\
(\cf\ my house's
$2.7\,\mbox{W/\ndegreeC/m$^2$}$).
\begin{figure}
\figuremargin{\small%
\begin{tabular}{@{}cccc@{}}
\multicolumn{4}{c}{%
\mbox{\epsfbox{metapost/heating.123}}
}\\
\raisebox{36mm}{\epsfig{width=36mm,angle=270,file=../../images/OldSchool.eps}}
&
\includegraphics[height=36mm]{../../images/Rutherford.eps}
&
\includegraphics[height=36mm]{../../images/LawFaculty.eps}
&
\includegraphics[height=36mm]{../../images/GatesCL2.eps}
\\
Old Schools
&
Rutherford building
&
Law faculty
&
Gates building\\
\end{tabular}
}{
\caption[a]{Building benchmarks.\index{Heatkeeper}\index{building!Heatkeeper}
Power used per unit area in various homes and offices.
}
\label{FigHeating123}
}
\end{figure}
With the house occupied by two people, the
average space-heating consumption, with the thermostat set at
19 or 20\degreesC\ during the day, was 8100\,kWh per year,
or 22\,kWh/d;
% actual consumption analysed to 3.62 kWh per degree day
% using I think 15.5 as the definition of a zero-degree-day
the total energy consumption for all purposes was
% 1584 kWh for hot water ,
% 14731 kWh for everything
% 16000 in the first year
about 15\,000\,kWh per year, or 40\,kWh/d.
% 8100 kWh/year / 140 m**2 in W/m**2
% 15000 kWh/year / 140 m**2 in W/m**2 ----> 12.2 Wmm
Expressed as an average power per unit area, that's
\Red{6.6\,\Wmm} for heating and
% . TYPO
\Red{12.2\,\Wmm} in total.
% 1.5m fluorescent tubes use 70W.
% Duncan Foster was T Blair's roommate
% His company worked on sizewll A and Wylfa
% In 2002 added an electric storage heater to enhance living room
% which was otherwise 2C lower than rest of house.
% At night (10.30pm to 7pm) thermostat is at 10C\@.
% thermostate settings now are 21 until 9am, 20 until 5pm, 21 until 10.30.
% At an average winter temp difference of 12C, the loss rate is 104.5 kWh/d
% and gains are 65.7 (from solar, cooking, lights, motors),
% so net losses required for heating are 38.78
% breakdown of heat losses (%): roof 44, floor 19, walls 27.5, windows 5.5,
% ventilation 4.
% In condensing gas boiler
\Figref{FigHeating123} compares the power consumption per unit area of
this Heatkeeper house with my house (before and after my efficiency push)
and with the European average. My house's post-efficiency-push consumption
is close to that of the Heatkeeper, thanks to the adoption of lower thermostat
settings.
\section{Benchmarks for houses and offices}
The German \ind{Passivhaus} standard aims for power consumption
for heating and cooling\index{building!Passivhaus}
of 15\,kWh/m$^2\!$/y, which is \Red{1.7\,\Wmm};
and total power consumption
of 120\,kWh/m$^2\!$/y, which is \Red{13.7\,\Wmm}.
% http://www.zerocarbonhouse.org.uk/passivhaus/
% http://www.passiv.de/English/PassiveH.HTM
% European average is 285 kWh / m2 / y which is 32.51Wmm
% My house before: 44 kWh per day per whole house 40+4
% which is 21\Wmm
% My house, now: 15 kWh per day per whole house 13+2
% which is 7.1\Wmm
% 13 kWh per day / 88 m**2 in W/m**2 -> 7.1 total (and 6.2 for heating)
%% SERVICE SECTOR ALL ENERGY:
% floor area of service sector buildings: 854 km**2
% 2005, total energy consumption: 19.320 M toe / y
% energy per person: 10.3 kWh/d.
% area per person: 14 sq m
% energy per unit area : 0.724 kWh/d/sq m = 30 \Wmm
The average energy consumption
of the UK service sector,
per unit floor area, is 30\,\Wmm.
% source \cite{ECUK}
% *** find out the area of their PV panels
\subsection{An energy-efficient office}
The National Energy Foundation built themselves
a low-cost low-energy building.
It has solar panels for hot water, solar photovoltaic (PV)
panels
generating up to 6.5\,kW of electricity,
and is heated by a 14-kW ground-source heat pump
and occasionally by a wood stove.
The floor area is 400\,m$^2$ and the number of
occupants is about 30.
It is a single-storey building.\index{building!energy-efficiency office}
The walls contain 300\,mm of rockwool insulation.
The heat pump's coefficient of performance in winter was 2.5.\label{pPoorCOP}
The energy used is 65\,kWh per year
per square metre of floor area
(\Red{7.4\,\Wmm}). The PV system
delivers almost 20\% of this energy.
% 1050 kWh/y per employee
% put me AFTER troublesome heating. diagram page % see BEFORE
% END \renewcommand{\floatpagefraction}{0.8}
}
\subsection{Contemporary offices}
New office buildings are often hyped up as being amazingly environment-friendly.
Let's look at some numbers.
% about the same time.
The
%% http://www.cabe.org.uk/default.aspx?contentitemid=1192&aspectid=10
William Gates building at Cambridge University\index{building!Cambridge University}
holds computer science researchers, administrators, and a small caf\'e.
% Roughly 274 people work there.
Its area is
11\,110\,m$^2$, and its energy consumption is\index{Cambridge University}
% 1982\,MWh/y.
2392\,MWh/y.
That's a power per unit area of
215\,kWh/m$^2$/y,
% *** check these numbers
or \Red{25\,\Wmm}.
% And 24\,kWh/d per person!
This building won a RIBA award in 2001
for its predicted energy consumption.
``The architects have incorporated many environmentally friendly features into the building.''
\tinyurl{5dhups}{http://www.arct.cam.ac.uk/UCPB/Place.aspx?rid=943658&p=6&ix=8&pid=1&prcid=27&ppid=201}
%%
%% 15 million
But are these buildings impressive?
Next door, the
Rutherford building, built in the 1970s without
any fancy eco-claims -- indeed without even double glazing --
%% Physics Rutherford Building 1595688.00352312 319.265306827356 4998.00000000
%pt9 := p0 yscaled 319.265306827356 xscaled 4.998000000 shifted point 1 of p8 ;
%p9 := p0 yscaled 219.204314866871 xscaled 4.998000000 shifted point 1 of p8 ;
%pg9 := p0 yscaled 92.3427068245512 xscaled 4.998000000 shifted point 3 of p9 ;
% 219.2+92.3 311.5 kWh/m**2/y
has a floor area of 4998 m$^2$
and consumes 1557\,MWh per year;
that's
0.85\,kWh/d/m$^2$, or
36\,\Wmm.
% Roughly 200? people work there.
% So that's 15\,kWh/d per person.
So the award-winning building is just 30\% better, in terms of power per unit area,
than its simple 1970s cousin.
% american eco house company
% http://www.enertia.com/
% ``Just below the surface, within reach of the average basement, is an infinite reservoir of heat that never drops below 50 degrees F.''
% Further reading: \cite{SolarHo}.
\Figref{FigHeating123}
compares these buildings
% Gates building, the Rutherford building,
and another new building, the Law Faculty,
with the Old Schools, which are ancient offices built pre-1890. For all the fanfare,
the difference between the new and the old is really quite disappointing!
% *** get photo of rutherford building or maybe cut reference to it.
Notice that the building power consumptions, per unit floor area,
are in just the same units (\Wmm) as the
renewable powers per unit area that we discussed
on pages \pageref{fig.plants155}, \pageref{plants99}, and \pageref{figW2}.
Comparing these consumption and production numbers helps us
realize how difficult it is to power modern buildings
entirely from \ind{on-site renewables}. The power per unit area of
biofuels (\figref{fig.plants155}, \pref{fig.plants155})
is 0.5\,\Wmm; of {\windfarm}s, 2\,\Wmm;
of solar photovoltaics, 20\,\Wmm\ (\figref{plants99},
\pref{plants99});
only solar hot-water panels come in at the right
sort of power per unit area, 53\,\Wmm\ (\figref{viridian}, \pref{viridian}).
%\marginfig{
%\caption[a]{Ancient and modern buildings}
%}
% So I think it makes sense for planning regulations to insist that
% solar water-heating should be incorporated into new buildings. But
% insisting that other renewable power should be generated on site
% seems a bit odd.
%% put all foster stuff above here
\begin{figure}
\figuredangle{\small
\begin{tabular}[b]{lr}
\multicolumn{1}{c}{\sf Cooling}&
\multicolumn{1}{c}{\sf Heating}\\
\mbox{\epsfbox{metapost/heatpump.22}}&
\mbox{\epsfbox{metapost/heatpump.21}}\\
\mbox{\epsfbox{metapost/heatpump.122}}&
\mbox{\epsfbox{metapost/heatpump.121}}\\
\end{tabular}
}{
\caption[a]{Ideal \ind{heat pump} efficiencies.\index{efficiency!heat pump}
Top left:
ideal electrical energy required, according to the
limits of thermodynamics, to pump heat {\em{out}\/} of a
place at temperature $T_{\rm{in}}$ when the heat is being pumped
to a place at temperature $T_{\rm{out}} = 35\degreesC$.
Right:
ideal electrical energy required to pump heat {\em{into}\/} a
place at temperature $T_{\rm{in}}$ when the heat is being pumped
from a place at temperature $T_{\rm{out}} = 0\degreesC$.
Bottom row: the efficiency is conventionally expressed
as a ``\ind{coefficient of performance},'' which is
the heat pumped per unit electrical energy.
In practice, I understand that well-installed
ground-source heat pumps and the best
air-source heat pumps usually have a
coefficient of performance of 3 or 4; however, government
regulations in Japan have driven the coefficient of performance
as high as 6.6.
}
\label{fig.gshptheory}
}\end{figure}
\section{Improving the coefficient of performance}
% While we are on the topic of heating, we should discuss
% the ultimate energy cost of two alternative styles
% of heating: electricity, or direct combustion.
% Also other options including heat pumps and
% combined heat and power.
You might think that the coefficient of performance
of a condensing boiler, 90\%, sounds pretty hard to beat.
But it can be significantly improved upon, by heat pumps.
Whereas the condensing boiler takes chemical energy and turns
90\% of it into useful heat, the
heat pump takes some electrical energy and uses it to {\em{move}\/}
heat from one place to another (for example, from outside
a building to inside). Usually the amount of useful
heat delivered is much bigger than the amount of electricity
used. A coefficient of performance of 3 or 4 is normal.
\subsection{Theory of heat pumps}
% A full explanation would require a discussion of entropy.
% {\em more here}
% For the time being, I'll just give
Here are the formulae
for the ideal efficiency of a \ind{heat pump}, that is, the electrical energy required
per unit of heat pumped. If we are pumping heat from an outside
place at temperature
$T_1$ into a place at higher temperature $T_2$, both temperatures being expressed
relative to absolute zero (that is, $T_2$, in kelvin,
is given in terms of the Celsius temperature $T_{\rm{in}}$,
by $273.15 + T_{\rm{in}}$), the ideal efficiency is:
\[
\mbox{efficiency} = \frac{T_2}{T_2 - T_1} .
% 1 - \frac{T_1}{T_2} .
\]
If we are pumping heat out from a place at temperature $T_2$ to
a warmer exterior at temperature $T_1$, the ideal efficiency is:
\[
\mbox{efficiency} = \frac{T_2}{T_1 - T_2} .
% \frac{T_1}{T_2} - 1 .
\]
These theoretical limits could only be achieved by systems that pump
heat infinitely slowly.
Notice that the ideal efficiency is bigger, the closer the inside temperature $T_2$
is to the outside temperature $T_1$.
% *** MOVE this sentence
% Ground-source heat pumps are discussed more in
% \chref{ch.gshp}.
While in theory
ground-source heat pumps might have better
performance than air-source, because the ground temperature is usually
closer than the air temperature to the indoor temperature,
in practice an air-source heat pump might be the best
and simplest choice.
In cities, there may be uncertainty about the future
effectiveness of ground-source heat pumps,
because the more people use them in winter, the colder the
ground gets; this \ind{thermal fly-tipping} problem may also
show up in the summer in cities where too many buildings
use ground-source (or should I say ``ground-sink''?)
heat pumps for air-conditioning.
\section{Heating and the ground}
Here's%
\margintab{\small
\begin{tabular}{@{}ll@{}}\toprule
Heat capacity: &$C= 820$\,J/kg/K \\
Conductivity: & $\kappa = 2.1$\,W$\!$/m/K\\
Density: & $\rho = 2750$\,kg/m$^3$ \\
\multicolumn{2}{@{}l}{Heat capacity
per unit
volume:}\\
&
$C_{\rm V} =
% \rho C =
2.3$\,MJ/m$^3$/K\\ \bottomrule
\end{tabular}
\caption[a]{Vital statistics for granite.\index{granite}
(I use \ind{granite} as an example of a typical rock.)
}
}
an interesting calculation to do.
Imagine having \ind{solar heating panels} on your roof,
and, whenever the water in the panels gets above
50\degrees\C, pumping the water through a large rock under
your house.
When a dreary grey cold month comes along, you could
then use the heat in the rock to warm your house.
% Normal ground-source heat pumps are different from this scheme in two ways:
% they don't usually bother with the solar heating panels
% and they use the cunning back-to-front refrigerator trick
% to boost
% the heat flow from the rock into the building.
% But before we discuss them, let's do this simple
% calculation for the solar scheme: r
Roughly
how big a 50\degree\C\ rock would you need to hold
enough energy to heat a house for a whole month?
Let's assume we're after 24\,kWh per day for 30 days
and that the house is at 16\degrees\C\@.
% the rock is perfectly insulated
% from the surrounding ground
The heat capacity of granite is
%% 0.195 from page 281 of Marks' Handbook.
%% Mechanical Engineers' Handbook
%% edited by Lionel S Marks. McGraw-Hill London 1951
%% and density is 2.5 (2.4-2.7) steel is 7.8. p 523
$0.195 \times
4200\,\J/\kg/\K = 820$\,J/\kg/K\@.
The mass of granite required is:
% pr 24*30*3.6e6 / 820 / 34
% 92969.8708751793
\begin{eqnarray*}
\mbox{mass} &=& \displaystyle\frac{ \mbox{energy} }{ \mbox{heat capacity} \times
\mbox{temperature difference} }
\\ &=& \displaystyle
\frac{ 24\times 30\times 3.6\,\MJ }{ ( 820\,\J/\kg/\ndegreeC ) (50{\degreesC}-16{\degreesC}) }
\\ &=&
100\,000\,\kg,
%% volume 37,000 litres, 37\,m^3 or 3.33**3 or 1*6*6
\end{eqnarray*}
100 tonnes, which corresponds to a cuboid of rock of size
$6\,\m \times 6\,\m \times 1\,\m$.
% cut material on area to _heating.tex
\subsection{Ground storage without walls}
\label{chSH}
OK, we've established the size of a useful ground store. But is it
difficult to keep the heat in? Would you need to surround your rock cuboid
with lots of insulation? It turns out that the ground itself is a pretty
good insulator.
\margintab{
\begin{center}
\begin{tabular}{lr}
\toprule
% \multicolumn{2}{r}{watts per metre-kelvin (\WmK)}
\multicolumn{2}{r}{(\WmK)}
\\ \midrule
water& 0.6 \\
% $ watt / (metre^2 \times kelvin metre^{-1}) $
%that is
quartz & 8\index{quartz} \\
%% http://dictionary.laborlawtalk.com/Thermal_conductivity
% Conductivity of
\ind{granite} &
2.1 \\ % \,{\WmK} \\
% 2.1\,Wm$^{-1}$K$^{-1}$.
earth's crust & 1.7 \\
dry soil & 0.14 \\
\bottomrule
\end{tabular}
\end{center}
\caption[a]{Thermal conductivities.\index{thermal conductivity}
For more data see \tabref{tab.condS}, \pref{tab.condS}.}
\label{ta.minicond}
}%
A spike of heat put down a hole in the ground will spread as
\[
\frac{1}{ \sqrt{4 \pi \kappa t} }\exp\left(
- \frac{x^2}{4 (\kappa/(C\rho)) t}
\right)
\]
where $\kappa$ is the conductivity of the ground,
$C$ is its \ind{heat capacity},
and $\rho$ is its density.
This describes a bell-shaped curve with
width
\[
\MidnightBlue{ \sqrt{ 2 \frac{\kappa}{C \rho} t } };
\]
for example, after six months ($t = 1.6 \times 10^7\,\s$),
using the figures for granite ($C = 0.82$\,kJ/\kg/K, $\rho = 2500$\,kg/m$^3$,
$\kappa = 2.1$\,{\WmK}), the width is
% sqrt( 2 2.1\,J/s/m/K * 1.6 \times 10^7\,\s
% / 820\,J/kg/C 2500$\,kg/m$^3$
% sqrt( 2 2.1 * 1.6 \times 10^7
% / 820 2500$/m$^2$
% = 6m
\MidnightBlue{6\,m}.
Using the figures for water ($C = 4.2$\,kJ/kg/K, $\rho = 1000$\,kg/m$^3$,
$\kappa = 0.6$\,{\WmK}), the width is
% sqrt( 2 0.6\,J/s/m/K * 1.6 \times 10^7\,\s
% / 4200\,J/kg/C 1000$\,kg/m$^3$
% = 6m
2\,m.
So if the storage region is bigger than $20\,\m\times20\,\m\times20\,\m$
then most of the heat stored will still be there in six months
time (because 20\,m is significantly bigger than 6\,m and 2\,m).
% The same formula also helps us decide how close together the
% pipes have to be in the storage region.
% When we get some hot water, we want to
% Two other constraints force the dimensions of the storage region:
% it must be big enough to hold all the energy that we want to
% leave there, and it must have enough surface area exposed to our pipes for
% us to be able to get the heat in.
\subsection{Limits of ground-source heat pumps}
The low thermal conductivity of the ground is a double-edged sword.
Thanks to low conductivity,
the ground holds heat well for a long time. But on the other hand,
low conductivity means that it's not easy to shove heat in and out of the ground
rapidly.
We now explore how the conductivity of the ground limits the use of
ground-source heat pumps.
\begin{figure}[!b]
\figuremargin{\small
\begin{center}
\begin{tabular}{l}
\raisebox{3cm}{\makebox[0in][l]{\sf temperature (\ndegreesC)}}%
\mbox{\epsfxsize=4in%
\mono%
{\epsfbox{../data/cambridge/mono/TempFit.eps}}%
{\epsfbox{../data/cambridge/TempFit.eps}}%
}
\end{tabular}
\end{center}
}{
\caption[a]{The temperature
in Cambridge, 2006, and a cartoon, which
says the temperature is the sum of an annual
sinusoidal variation
% of amplitude 8.33\degreesC
between $3$\degreesC\
and
$20$\degreesC,
and a daily sinusoidal variation
with range up to 10.3\degreesC\@.
% amplitude 5.15
The average temperature is 11.5\degreesC\@.
}
\label{TempFit}
}
\end{figure}
Consider a neighbourhood with quite
a high population density. Can {\em{everyone}\/} use ground-source heat pumps,
without using active summer replenishment (as discussed on \pref{pSummerReplen})?
The concern is that if we all sucked heat from the ground at the same
time, we might freeze the ground solid.
I'm going to address this question by two calculations.
First, I'll work out the natural flux of energy in and out of the ground in summer
and winter.
If the flux we want to suck out of the ground in winter is much bigger than
these natural fluxes then we know that our sucking is going to significantly
alter ground temperatures, and may thus not be feasible.
For this\label{pHP1} calculation, I'll assume the ground just below the surface
is held, by the combined influence of sun, air, cloud, and
night sky, at a temperature that varies slowly up and down
during the year (\figref{TempFit}).
{%%%%%%%%%%%%%%%%%%%%%% troublesome
% put me BEFORE troublesome heating. diagram page % see AFTER
\renewcommand{\floatpagefraction}{0.8}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Response to external temperature variations}
Working out how the temperature inside the ground responds,
and what the flux in or out is,
requires some advanced mathematics, which I've cordoned off
in box \ref{box.fluxtheory} (\pref{box.fluxtheory}).
The payoff from this calculation is a rather beautiful
diagram (\figref{TempDep}) that shows how the temperature varies
in time at each depth. This diagram shows the answer for
any material in terms of the {\dem{characteristic length-scale}\/}
$z_0$ (\eqref{eq.charleng}), which depends on the
conductivity $\kappa$ and heat capacity $C_{\rm V}$ of the material,
and on the frequency $\omega$ of the external temperature variations.
(We can choose to look at either daily and yearly variations using the same
theory.)
At a depth of 2$z_0$, the variations in temperature
are one seventh of those at the surface, and
lag them by about one third of a cycle (\figref{TempDep}).
At a depth of 3$z_0$, the variations in temperature
are one twentieth of those at the surface, and
lag them by half a cycle.
% At depth $z_0$, the temperature oscillations are reduced to
% 37\%, and at depth $2z_0$, they are reduced to just 14\%
% of the external amplitude.
For the case of daily variations and solid granite,
the characteristic length-scale is
$z_0 = 0.16\,\m$. (So 32\,cm of rock is the thickness you need to ride out
external daily temperature oscillations.)
For yearly variations and solid granite, the characteristic length-scale is
$z_0 = 3\,\m$.
% sustainable/data/cambridge
% gnuplot < gnuDep ; gv TempDepth.eps
\marginfig{\small
\begin{center}
\begin{tabular}{@{}l@{}}
\mbox{\epsfxsize=53mm%
\mono%
{\epsfbox{../data/cambridge/mono/TempDepthS.eps}}%
{\epsfbox{../data/cambridge/TempDepthS.eps}}%
}\\
\end{tabular}
\end{center}
% used to be - rather beautiful
%{\epsfbox{../data/cambridge/mono/TempDepth.eps}}%
%{\epsfbox{../data/cambridge/TempDepth.eps}}%
\caption[a]{Temperature (in \ndegreesC)
versus depth and time.
% in \ind{granite}.
The depths are given in units of the
characteristic depth $z_0$, which
for granite and annual variations is 3\,m.\smallskip
% \begin{oldcenter}
% \begin{tabular}{ll} \toprule
% depth 0 & surface \\
% depth 1 & 3\,m \\
% depth 2 & 6\,m \\
% depth 3 & 9\,m \\ \bottomrule
% \end{tabular}
% \end{oldcenter}
At ``depth 2''
% of $2z_0$
(6\,m),
the temperature is always about 11 or 12\degreeC\@.
At ``depth 1'' (3\,m), it wobbles
between 8 and 15\degreeC\@.
}
\label{TempDep}
%% gnuDep
}
\begin{table}[!b]
\figuremargin{\small
\begin{tabular}{lllll} \toprule
& thermal & heat & length-scale & flux \\
& conductivity & capacity & & \\
& $\kappa$ & $C_{\rm V}$ & $z_0$ & $A \sqrt{ { C_{\rm V} \kappa \omega } }$
% z_0 = \sqrt{ \frac{2 \kappa }{ C_{\rm V} \omega } }.
\\
& (\WmK) & (MJ/m$^3$/K) & (m) & (\Wmm) \\
\midrule
Air & 0.02 & 0.0012 \\
% see data/soil.m
Water & 0.57 & 4.18 & 1.2 & 5.7 \\
Solid granite & 2.1 & 2.3 & 3.0& 8.1 \\
Concrete & 1.28 & 1.94 & 2.6& 5.8\\[0.1in]
{\em Sandy soil} \\
dry & 0.30 & 1.28 & 1.5 & 2.3\\
50\% saturated & 1.80 & 2.12 & 2.9 & 7.2\\
100\% saturated & 2.20 & 2.96 & 2.7 & 9.5\\[0.1in]
{\em Clay soil} \\
dry & 0.25 & 1.42 & 1.3 & 2.2\\
50\% saturated & 1.18 & 2.25 & 2.3 & 6.0\\
100\% saturated & 1.58 & 3.10 & 2.3 & 8.2\\[0.1in]
{\em Peat soil} \\
dry & 0.06 & 0.58 & 1.0 & 0.7\\% 69\\
50\% saturated & 0.29 & 2.31 & 1.1 & 3.0\\
100\% saturated & 0.50 & 4.02 & 1.1 & 5.3\\
\bottomrule
\end{tabular}
}{\caption[a]{Thermal conductivity and heat capacity
of various materials and soil types, and the
deduced length-scale
$z_0 = \sqrt{ \frac{2 \kappa }{ C_{\rm V} \omega } }$
and
peak flux
$A \sqrt{ { C_{\rm V} \kappa \omega } }$
associated with annual temperature variations
with amplitude $A=8.3\degreesC$.
The sandy and clay soils have porosity 0.4;
the peat soil has porosity 0.8.
}\label{tab.condS}}
\end{table}
Let's focus on annual variations and discuss a few other materials.
Characteristic length-scales for various materials are in the third
column of \tabref{tab.condS}.
For damp sandy soils or concrete, the characteristic length-scale
$z_0$ is similar to that of granite -- about 2.6\,m.
In dry or peaty soils, the length-scale
$z_0$ is shorter -- about 1.3\,m.
That's perhaps good news because it means you don't have to dig so deep to find
ground with a stable temperature. But it's also coupled with some bad news:
the natural fluxes are smaller in dry soils.
The natural flux varies during the year
% , and lags the external temperature
% by 8 weeks. The flux into the ground is biggest in
and has a peak value (\eqref{eqAmpFlux})
that is smaller, the smaller the \ind{conductivity}.
For the case of solid granite, the peak flux is 8\,\Wmm.
For dry soils, the peak flux ranges from 0.7\,\Wmm\ to 2.3\,\Wmm.
For damp soils, the peak flux ranges from 3\,\Wmm\ to 8\,\Wmm.
What does this mean?
I suggest we take a flux in the middle of these numbers, 5\,\Wmm,
as a useful benchmark, giving guidance
about what sort of power we could expect to extract, per unit area, with a
ground-source heat pump.
If we suck a flux significantly smaller than 5\,\Wmm, the perturbation
we introduce to the natural flows will be small.
If on the other hand
we try to suck a flux bigger than 5\,\Wmm, we should expect that
we'll be shifting the temperature of the ground
significantly away from its natural value, and such fluxes
may be impossible to demand.
The population density of a typical English suburb corresponds
to 160\,m$^2$ per person (rows of semi-detached houses with about 400\,m$^2$ per
house, including pavements and streets).\label{pPickDen}
% 6200/km$^2$
% that's
At this density of residential area, we can deduce that
a ballpark limit for heat pump power delivery is
\[
5\,\Wmm \times 160\,\m^2 = 800\,\W = 19\,\kWh/d\mbox{ per person}.
\]
This is uncomfortably close to the sort of power we would like to
deliver in winter-time: it's plausible that our peak winter-time
demand for hot air and hot water, in an old house like mine, might be
40\,\kWh/d per person.
This calculation suggests that in a typical suburban area, {\em not
everyone can use ground-source heat pumps}, unless they are careful to
actively dump heat back into the ground during the summer.
Let's do a second calculation, working out how much power we could
steadily suck from a ground loop at a depth of $h=2$\,m.
Let's assume that we'll allow ourselves to suck the temperature at the ground
loop down to
$\Delta T = 5\degreesC$ below the average ground temperature at the surface,
and let's assume that the surface temperature is constant.
We can then deduce the heat flux
from the surface. Assuming a conductivity of 1.2\,\WmK\ (typical of damp clay soil),
\[
\mbox{Flux} =
%\mbox{Conductivity}
\kappa \times \frac{\Delta T}{h} = 3\,\Wmm.
% 1.2 * 5 / 2
\]
If, as above, we
% on \pref{pPickDen}, we
assume a population density corresponding to
160\,m$^2$ per person,
then the maximum power per person deliverable by ground-source
heat pumps, if everyone
in a neighbourhood has them,
is 480\,W, which is 12\,kWh/d per person.
% Add in the electrical contribution, assuming a COP of 3: 17\,kWh/d per person.
So again we come to the conclusion that in a typical suburban area
composed of poorly insulated houses like mine, {\em not
everyone can use ground-source heat pumps}, unless they are careful to
actively dump heat back into the ground during the summer.
And in cities with higher population density, ground-source heat pumps
are unlikely to be viable.
I therefore suggest air-source heat pumps are the best heating choice for
most people.
\section{Thermal mass}
\nocite{SolarHo}Does increasing the \ind{thermal mass} of a building\index{building!thermal mass}
% *** undefined?
help reduce its heating and cooling bills?
It depends. The outdoor temperature can vary during the
day by about 10\degreesC\@.
A building with large thermal mass -- thick stone walls, for example --
will naturally ride out those variations in temperature, and, without
heating or cooling, will have a temperature close to the average outdoor
temperature. Such buildings, in the UK, need neither heating nor cooling
for many months of the year.
In contrast, a poorly-insulated
building with low thermal mass might be judged too hot
during the day and too cool at night, leading to greater expenditure
on cooling and heating.
However, large thermal mass is not always a boon. If a room is
occupied in winter for just a couple of hours a day (think of a
lecture room for example),
the energy cost of warming the room up to a comfortable temperature will
be greater, the greater the room's thermal mass.
This extra invested heat will linger for longer in a thermally massive
room, but if nobody is there to enjoy it, it's wasted heat.
%% occupying the room
So in the case of in\-fre\-quent\-ly-used rooms it makes
sense to aim for a structure with low thermal mass,
and to warm that small mass rapidly when required.
% put me AFTER troublesome heating. diagram page % see BEFORE
% END \renewcommand{\floatpagefraction}{0.8}
}
\begin{boxfloat}
\figuremargin{
\begin{framedalgorithm}\small
If we assume the ground is made of solid homogenous
material with conductivity $\kappa$ and heat capacity $C_{\rm V}$,
then the temperature at depth $z$ below the ground
and time $t$
responds to the imposed temperature at the surface
in accordance with the diffusion equation
\beq
\frac{ \partial T(z,t)}{\partial t} = \frac{ \kappa }{ C_{\rm V} }
\frac{ \partial^2 T(z,t) }{\partial z^2 } .
\eeq
For a sinusoidal imposed temperature with frequency $\omega$
and amplitude $A$ at depth $z=0$,
\beq
T(0,t) = T_{\rm surface}(t) = T_{\rm average} + A \cos( \omega t ) ,
\eeq
the resulting temperature
at depth $z$ and time $t$ is a decaying and oscillating function
\beq
T(z,t) = T_{\rm average} + A \,e^{-z/z_0} \cos( \omega t - {z}/{z_0} ),
\eeq
where $z_0$ is the characteristic length-scale of both the decay and
the oscillation,
\beq
z_0 = \sqrt{ \frac{2 \kappa }{ C_{\rm V} \omega } }.
\label{eq.charleng}
\eeq
The flux of heat (the power per unit area) at depth $z$ is
\beq
\kappa
\frac{ \partial T }{\partial z }
= \kappa \frac{A }{ z_0 } \sqrt{2} e^{-z/z_0}
\sin ( \omega t - z/z_0 - \pi/4 ) .
\eeq
For example, at the surface, the peak flux is
\beq
\kappa \frac{A }{ z_0 } \sqrt{2} =
A \sqrt{ { C_{\rm V} \kappa \omega } }.
\label{eqAmpFlux}
\eeq
% which
%% omega = 2*pi / (365.25*24*3600.0)
%% A=8.336 ; CV = 2255.0e3 ; kappa = 2.1 ; pr A*sqrt( CV*kappa* omega)
%% 8.09
% for the yearly driving signal of amplitude $A=8.3$\degreesC\
% corresponds to 8\,\Wmm.
\end{framedalgorithm}
}{
\caption[a]{Working out the natural flux caused by sinusoidal temperature variations.}
\label{box.fluxtheory}
}
\end{boxfloat}
\small
\section{Notes and further reading}
\begin{notelist}
\item[page no.]
% \item[]
% [K-value is thermal conductivity, usually measured in W$\!$/m/K, for example
% 0.023\,W$\!$/m/K\@. Sometimes also called $\lambda$-value.
% R-value is thermal resistance (the inverse of U-value), usually
% measured in m$^2$K/W.]
%\item[air-changes]
\item[\npageref{tab.condS}]
{\nqs{\Tabref{tab.condS}.}}
Sources:
\cite{SoilCond},
% http://books.google.co.uk/books?id=3lV1PFb-vz0C&pg=PA188&lpg=PA188&dq=conductivity+and+heat+capacity+of+clay&source=web&ots=UJN8kBqWfX&sig=dC_axYg-892RhY4HHFnZwl95FA4&hl=en&sa=X&oi=book_result&resnum=3&ct=result
\par
\myurlb{www.hukseflux.com/thermalScience/thermalConductivity.html}{http://www.hukseflux.com/thermalScience/thermalConductivity.html}
\end{notelist}
\normalsize
% http://www.ukace.org/pubs/reportfo/BuildIgn.pdf
%\input{smartheating2.tex}%gshp
\chtweak\chtweak\chtweak\chtweak
\gset\chapter{\gcol{Waves II}}
\label{ch.waves2}
\section{The physics of deep-water waves}
% \index{cheese@gouda}
% Would place gouda in the list right next to cheese, as if gouda was actually spelled cheese
Waves contain energy\index{wave}\index{energy!wave}
in two forms: \ind{potential energy}, and \ind{kinetic energy}.
The potential energy is the energy required to move all the water
from the troughs to the crests.
The kinetic energy is associated with the water moving around.
People sometimes assume that when the crest of a wave moves across
an ocean at 30\,miles per hour, the water in that crest must also
be moving at 30\,miles per hour in the same direction. But this isn't so.
It's just like a \ind{Mexican wave}\index{wave!Mexican}.
When the wave rushes round the \ind{stadium},
the humans who are making the wave aren't themselves moving round the stadium:
they just bob up and down a little. The motion of a piece of water
in the ocean is similar: if you focused on a bit of seaweed floating
in the water as waves go by, you'd see that the seaweed moves up and down,
and also a little to and fro in the direction
of travel of the wave -- the exact effect could
be recreated in a Mexican wave if people moved like window-cleaners,
polishing a big piece of glass in a circular motion.
The wave has potential energy because of the elevation of the crests
above the troughs. And it has kinetic energy because of
the small circular bobbing motion of the water.
\marginfig{
\begin{center}
\hspace*{3mm}\begin{tabular}{l}
%\mbox{\ \ \epsfxsize=45mm\epsfbox{../wave/wPowerDen.eps}} \\[0.16in]
\mbox{\epsfxsize=49mm\epsfbox{../wave/wWindSpeed.eps}} \\[0.16in]
\mbox{\epsfxsize=49mm\epsfbox{../wave/wPeriod.eps}} \\[0.16in]
\mbox{\epsfxsize=49mm\epsfbox{../wave/wWavelength.eps}} \\[0.16in]
\mbox{\epsfxsize=49mm\epsfbox{../wave/wPower.eps}} \\[0.16in]
\end{tabular}
\end{center}
\caption[a]{
Facts about deep-water waves.\index{wave!deep-water}
In all four figures the horizontal axis is the wave speed in m/s.
From top to bottom the graphs show:
wind speed (in m/s) required to make a wave with this wave speed;
period (in seconds) of a wave;
wavelength (in m) of a wave;
and power density (in kW$\!$/m) of a wave with amplitude 1\,m.
}
\label{fig.waveTheory}
}
%% power density per unit area is 1000 W/m**2 for a wave of
%% speed 7.5 m/s (ie period 5s) made by a force 7 wind.
\begin{figure}
% \figuremargin{
\figuredangle{
\begin{center}
%\mbox{\epsfxsize=3in\epsfbox{../../images/wave.eps}}
\mbox{\epsfbox{metapost/wave.1}}
\end{center}
}{
\caption[a]{A \ind{wave}
% , yesterday. The wave
has energy in two forms:
potential energy associated with raising water out of the
light-shaded troughs into the heavy-shaded crests;
and kinetic energy of all the water within a few wavelengths
of the surface -- the speed of the water is indicated by the small arrows.
The speed of the wave, travelling from left to right, is indicated by
the much bigger arrow at the top.
}\label{waveYesterday}
}
\end{figure}
Our rough calculation of the power in ocean waves will require
three ingredients:
an estimate of the period $T$ of the waves (the time between crests),
an estimate of the height $h$ of the waves,
and a physics formula\index{formula!wave}
that tells us how to work out the speed $v$ of the
wave from its period.
The \ind{wavelength} $\lambda$
and \ind{period} of the \ind{wave}s (the distance and time
respectively between
two adjacent crests) depend on the \ind{speed} of the \ind{wind}
that creates the waves, as shown in \figref{fig.waveTheory}.
The height of the waves doesn't depend on the windspeed; rather, it
depends on how long the wind has been caressing the water surface.
You can estimate the period of ocean waves
by recalling the time between
waves arriving on an ocean \ind{beach}. Is 10 seconds reasonable?
For the height of ocean waves, let's assume an amplitude of 1\,m, which
means 2\,m from trough to crest. In waves this high, a man in a dinghy can't
see beyond the nearest crest when he's in a trough;
I think this height is bigger than average, but we can revisit this estimate if
we decide it's important.
The speed of deep-water waves is related to
the time $T$ between crests by the physics formula
(see \citeasnoun{Faber}, p170):
\[
v = \frac{g T}{2 \pi} ,
\]
where $g$\index{g@$g$} is the acceleration of \ind{gravity} (9.8\,m/s$^2$).
For example, if $T = 10$ seconds, then
$v = 16\,\m/\s$.
The \ind{wavelength} of such a wave -- the distance between crests --
\index{$\lambda$}\index{l@$\lambda$}is $\lambda = vT = g T^2 / 2\pi = 160\,\m$.
For a wave of wavelength $\lambda$
and period $T$,
% = 10$ seconds,
if the height of
each crest and depth of each trough
is $h = 1$\,m, the potential energy passing per unit time, per unit length,
is
\beq
{P}_{\rm potential} \simeq m^* g \bar{h} / T,
\eeq
where $m^*$ is the mass per unit length,
which is roughly $\half \rho h (\lambda/2)$ (approximating the
area of the shaded crest in \figref{waveYesterday}
by the area of a triangle),
and $\bar{h}$ is the change in height of the centre-of-mass
of the chunk of elevated water, which is roughly $h$.
So
\beq
{P}_{\rm potential} \simeq \frac{1}{2} \rho h \frac{\lambda}{2} g h / T .
\eeq
(To find the potential energy properly, we should have done an integral
here; it would have given the same answer.)
Now $\lambda/T$ is simply the speed at which the wave travels, $v$, so:
\beq
{P}_{\rm potential} \simeq \frac{1}{4} \rho g h^2 v .
\eeq
Waves
have kinetic energy as well as potential energy,
and, remarkably, these are exactly equal, although I don't
show that calculation here;
so the total power of the waves is double the power calculated
from potential energy.
\beq
{P}_{\rm total} \simeq \frac{1}{2} \rho g h^2 v .
\label{eqPwrong}
\eeq
%% in page 17 of the dti atlas 'see appendix D1' they use
%% the formula
%% 0.0623 rho g H^2 c_g
%% where H is the ``significant wave height'' which is defined to be the height of the highest
%% one third of waves in the sea.
%% My height is probably H_rms ?? = H_s / 1.416
%% c_f = 0.5c (1 + 2 k h / sinh 2 k h )
%% (from appendix D) where h is vater depth and k is wavenumber and c = sigma/k.
%% c=gT/ 2 pi in deep water.
%% and c_g is the wave group speed, which is HALF of the phase velocity
%% My formula says
%% (1/2) rho g h^2 * (2 c_g )
%% which is 16 times bigger than their figure. WHAT????
%% I guess their definition of H is whacky
%% they start from (1/8) rho g h^2 * c_g
There's only one thing wrong with this answer: it's too big, because we've
neglected a strange property of dispersive waves: the energy in the wave doesn't actually
travel at the same speed as the crests; it travels at a speed called the group
velocity, which for deep-water waves is {\em{half}\/} of the speed $v$.
You can see that the energy travels slower than the
crests by chucking a pebble in a pond and watching the
expanding waves carefully.
% -- you'll see that the crests move faster then the disturbance
% itself. Rather paradoxical, but true.
What this means is that \eqref{eqPwrong}
is wrong: we need to halve it. The correct power per unit length of wave-front is
\beq
{P}_{\rm total} = \frac{1}{4} \rho g h^2 v .
\label{eqPwrongright}
\eeq
Plugging in $v=16\,\m/\s$ and $h=1\,\m$, we find
\beq
{P}_{\rm total} = \frac{1}{4} \rho g h^2 v
% = 0.5 \times 1000\, \times 10 x 1 x 1 \times 16.
= 40 \, \kW\!/\m .
\eeq
This rough estimate agrees with real measurements in the Atlantic
\citep{Mollison85}. (See \pref{pMolli}.)
% Deep water power in Australia averages 18\,kW/m
The losses from \ind{viscosity} are minimal:
a wave of 9\,seconds period would have to go three times round the
world to lose 10\% of its amplitude.
\section{Real wave power systems}
\subsection{Deep-water devices}
%% see _waves.tex
How effective are real systems at extracting power from waves?
\index{Salter, Stephen!duck}\index{duck, Salter}Stephen Salter's
``duck'' has been well characterized:
a row of 16-m diameter ducks, feeding off \ind{Atlantic} waves with
an average power of 45\,k\Wm, would
deliver 19\,k\Wm,
including transmission to central Scotland
\citep{Mollison85}.
% suck about 50\% of the power out
% of incoming \ind{Atlantic} waves, and the efficiency of the remaining
% steps (conversion to electricity, and
% transmission to a ``\ind{hydrodynamically underprivileged area}''
% such as London) would be about 60\%.
% Thus deep water Salter Ducks, feeding off 45\,k\Wm, would
% deliver 19\,k\Wm,
% including transmission to central Scotland
% \citep{Mollison85}.
The \ind{Pelamis}\index{sea snake} device, created by
\ind{Ocean Power Delivery},
has taken over the Salter duck's mantle as the
leading floating deep-water wave device.
Each snake-like device is 130\,m long and is made of
a chain of four segments, each
3.5\,m in diameter. It has a maximum power output of 750\,kW\@.
The Pelamises are designed to be moored in a depth of about 50\,m.
In a wavefarm, 39 devices in three rows would face the principal
wave direction, occupying an area of ocean
about 400\,m long and 2.5\,km wide (an area of 1\,km$^2$).
The effective cross-section of a single Pelamis is 7\,m (\ie, for
good waves, it extracts 100\% of the energy that would cross 7\,m).
The company says that such a wave-farm would deliver about 10\,k\Wm.
% (10\,MW/km).
% # width required for 400m at 55.8311, Longitude = -6.4561
% -- 55.8310, Longitude = -6.4479
% change in long of
\subsection{Shallow-water devices}
Typically 70\% of energy in ocean waves is lost
through \index{friction!waves}\index{bottom friction}bottom-friction
as the depth decreases from
100\,m to 15\,m.
% need a source for that
So the average wave-power per unit length of coastline
in shallow waters is reduced to about 12\,k\Wm.
% per metre.
The \ind{Oyster}, developed by \ind{Queen's University Belfast}
and \ind{Aquamarine Power Ltd} [\myurlb{www.aquamarinepower.com}{http://www.aquamarinepower.com/}],
is a bottom-mounted flap, about 12\,m high,
that is intended to be deployed in
waters about 12\,m deep,\nlabel{oyster}
%Oyster® modules are designed for deployment around 10m depth,
in areas where the average incident wave power is greater than 15\,k\Wm.
% \myurl{http://www.aquamarinepower.com/}
Its peak power is 600\,kW\@.
A single device would produce about 270\,kW in wave heights greater than 3.5\,m.
It's predicted that an Oyster would have
% Assume its width is about 20\,m? Then the ideal power for a device of
% cross-section 20\,m would be 240\,kW\@.
% A rough average figure is about 100\,kW\@.
% A smaller power than the Pelamis,
% but
a bigger power per unit mass of hardware than a Pelamis.\index{shallow water}\index{water!shallow}
% *** WHAT MASS oyster
% this no good:
% http://www.raeng.org.uk/policy/reports/pdf/energy_2100/Trevor_Whittaker.pdf
% *** Need to add cite here
Oysters could also be used to directly drive \index{reverse osmosis}{reverse-osmosis}
\ind{desalination} facilities.
``The peak freshwater output of an Oyster
desalinator is between 2000 and 6000\,m$^3$/day.''
That rate of
production has a value, going by the \ind{Jersey} facility (which uses
8\,kWh per m$^3$),
equivalent to
% 16\,000--48\,000\,kWh per day, that is,
600--2000\,kW of electricity.
%%% Need to add notes with citation. see sustainable/refs/wave/Oyster for papers, and accompanying email from jessica.owen for citations
\chtweak
\gset\chapter{\gcol{Tide II}}
\label{ch.tide2}
\label{app.tide2}
\section{Power per unit area of tidal pools}
\label{pTidePool}
% \section{Tide pool power}
% \subsection{Production on ebb and flood}
% {\sc The power of an artificial tide pool in more detail.}
To estimate the power of an artificial \tidepool, imagine that it's filled
\marginfig{
\begin{center}
\mbox{\epsfbox{metapost/tide.3}}
\end{center}
\caption[a]{
A \tidepool\ in cross section.
The pool was filled at high tide, and now it's low tide.
We let the water out through the electricity generator
to turn the water's potential energy into electricity.
}\label{tidepool2}
}%
rapidly at high tide, and emptied rapidly at low tide.
Power is generated in both directions, on the ebb\index{tide!two-way generation}
and on the flood. (This is called \ind{two-way generation} or \ind{double-effect generation}.)
The change in potential energy of the water, each six hours, is
$mgh$, where $h$ is the change in height of the centre of
mass of the water, which is half the range. (The range is the
difference in height between low and high tide;
\figref{tidepool2}.)\label{pagetidepool2}
The mass per unit area covered by tide-pool
is $\rho \times (2 h)$, where $\rho$ is the density
of water ($1000\,\kg/\m^3$).
So the power per unit area generated by a {\tidepool} is
\[
\frac{ 2 \rho h g h}{ \mbox{6\,hours} },
\]
assuming perfectly efficient generators.
Plugging in $h = 2\,\m$ (\ie, range 4\,m), we find the
power per unit area of tide-pool
is $3.6\,\Wmm$.
Allowing for an efficiency of 90\% for conversion of this power to
electricity,\nlabel{Turbine90} we get
\[
\mbox{power per unit area of tide-pool}
% \frac{ 2 \rho h g h}{ \mbox{6\,hours} }
% = 0.9 * 2000 kg/m^3 * 4*9.81 m^2 m/s/s / (6*3600)s
% = 3.27 W/m^2
\: \simeq \: \OliveGreen{3\,\Wmm}.
\]
So to generate 1\,GW of power (on average),
we need a {\tidepool} with an area of about 300\,km$^2$.
A circular pool with diameter 20\,km would do the trick.
(For comparison, the area of the Severn estuary behind
the proposed barrage is about 550\,km$^2$,
and the area of the Wash is more than 400\,km$^2$.
If a {\tidepool} produces electricity in one direction only, the power per
unit area is halved.
The average power per unit area of the tidal barrage at La Rance,
where the mean tidal range is 10.9\,m, has been
% where the tidal range is at most 13.5\,m, has been
\OliveGreen{2.7\,\Wmm} for decades (\pref{pRanceFacts}).
% mean range from novak page 98 WilsonBallsTide
\section{The raw tidal resource}
% \subsection{Tides as tidal waves}
The tides around Britain are genuine
tidal waves.\index{tide!as waves}\index{wave!tides as waves}
(Tsunamis\index{tsunami}, which are called ``tidal waves,'' have nothing to do with tides:
they are caused by underwater landslides and earthquakes.)
The location of the high tide (the crest of the tidal wave)
moves much faster than the tidal
flow -- 100 miles per hour, say, while the water itself
moves at just 1 mile per hour.
% \subsection{Sanity-check using total arriving power}
\begin{figure}[thbp]
% \figuremargin{
\figuredangle{
\begin{center}
\mbox{\epsfbox{metapost/tide.1}}
\end{center}
}{
\caption[a]{A shallow-water wave.\index{wave!shallow-water}
Just like a deep-water wave, the wave has energy in two forms:
potential energy associated with raising water out of the
light-shaded troughs into the heavy-shaded crests;
and kinetic energy of all the water moving around
as indicated by the small arrows.
The speed of the wave, travelling from left to right, is indicated by
the much bigger arrow at the top.
For tidal waves,
a typical depth might be 100\,m,
%% v = sqrt(g d) = sqrt( 1000 )
the crest velocity 30\,m/s,
the vertical amplitude at the surface 1 or 2\,m,
and the water velocity amplitude
%% U = v h/d = 30 * 2/100 = 0.6
0.3 or 0.6\,m/s.
}
\label{fig.shallowwave}
}
\end{figure}
The energy we can extract from tides, using tidal pools
or {\tidefarm}s, can never
be more than the energy of these tidal waves
from the Atlantic. We can estimate the total power
of these great Atlantic tidal waves in the same
way that we estimate the power of
% their smaller cousins,
ordinary wind-generated waves.
The next section describes a
standard model for the power arriving in travelling waves
in water of depth $d$ that is shallow compared to the
wavelength of the waves (\figref{fig.shallowwave}).
The power per unit length of wavecrest of shallow-water tidal waves is
\beq
\rho g^{3/2} \sqrt{ d } h^2/2.
\label{eqRawPo}
\eeq
% From this formula, a ballpark estimate for the power coming
\Tabref{tab.pfluxtid} shows the power per unit length of wave crest
for some plausible figures.
If $d = 100\,\m$,
and $h = 1$ or $2\,\m$, the power per unit length of wave crest is
% in kW/m: p(h) = 9.81**1.5 * 10 * h**2
% in kW/m: p(h,d) = 9.81**1.5 * sqrt(d) * h**2
$150$\,\kWm\ or $600\,$\kWm\ respectively.\index{power per unit length!tide}
These figures are impressive compared with the raw power per unit
length of ordinary Atlantic deep-water waves, 40\,\kWm\ (\chref{ch.waves2}).
Atlantic waves and the Atlantic tide have similar
vertical amplitudes (about 1\,m), but the raw power in tides
is roughly 10 times bigger than that of ordinary wind-driven waves.
% Fortunately we don't have to depend on my rough model of incoming tidal
% power.
\citet{Taylor1920} worked out a more detailed model of tidal power that includes
important details such as the Coriolis effect (the effect produced
by the earth's daily rotation), the existence of
% counter-propagating
tidal waves travelling in the opposite direction, and the
direct effect of the moon on the energy flow in the Irish Sea. Since then,
experimental measurements and computer models have verified and
extended Taylor's analysis.
\amargintab{t}{
\begin{center}
\begin{tabular}{cc}\toprule
$h$ & $ \rho g^{3/2} \sqrt{ d } h^2/2$ \\
(m) & (\kWm) \\ \midrule
0.9& 125 \\
1.0& 155 \\
1.2& 220 \\
1.5& 345 \\
1.75& 470 \\
2.0 & 600 \\ % 1230
2.25& 780 \\ % 1555
\bottomrule
\end{tabular}
\end{center}
\caption[a]{Power fluxes (power per unit length of wave crest)
for depth $d=100\,\m$. }
\label{tab.pfluxtid}
}
%
\citet{Flather1976} built a detailed numerical model of the
lunar tide, chopping the continental shelf around the British Isles into
roughly 1000 square cells.
Flather estimated that the total average power entering this region
is 215\,GW\@.
According to his model,
180\,GW enters the gap between France and Ireland.
From Northern Ireland round to Shetland, the incoming power is 49\,GW\@.
Between Shetland and Norway there is a net loss of 5\,GW\@.
%
% [Compare with 215--250\,GW estimated in the literature; of which 64\,GW
% estimated to enter the Irish Sea. \cite{Blunden}.
As shown in \figref{fig.TideLine2}, \citet{Cartwright1980}
found experimentally that the
average
% M2
power transmission was
60\,GW between \ind{Malin Head} (Ireland) and \ind{Flor{\o}} (\ind{Norway})
and 190\,GW between \ind{Valentia}
(\ind{Ireland}) and the Brittany coast near Ouessant.
The power entering the Irish Sea was found to be
45\,GW, and entering the North Sea
via the Dover Straits, 16.7\,GW\@.
% Near the Orkneys the incoming powers
% are 14\,GW and 12\,GW\@.
\subsection{The power of tidal waves}
\label{sec.powerT}
This section, which can safely be skipped,
provides more details behind the
formula for tidal power used in the previous section.
I'm going to go into this model of tidal power in some detail
because most of the official estimates of the UK tidal resource
have been based on a model that I believe is incorrect.
\Figref{fig.shallowwave} shows a model for a tidal wave travelling
across relatively shallow water.
This model is intended as a cartoon, for example, of tidal
crests moving up the English channel or down the North Sea.
It's important to distinguish the speed $U$ at which the water itself moves
(which might be about 1 mile per hour)
from the speed $v$ at which the high tide moves,
which is typically 100 or 200 miles per hour.
The water has depth $d$.
Crests and troughs of water are injected from the left hand side
by the 12-hourly ocean tides.
The crests and troughs move with velocity
\beq
v= \sqrt{ g d }.
\label{eqv}
\eeq
We assume that the wavelength is much bigger than the depth, and
we neglect details such as Coriolis forces and density variations in the water.
Call the vertical amplitude of the tide $h$.
For the standard assumption of nearly-vorticity-free flow,
the horizontal velocity of the water is near-constant with depth.
The horizontal velocity $U$ is proportional to the surface displacement
and can be found by conservation of mass:
\beq
U = v h/d.
\label{eqU}
\eeq
If the depth decreases, the wave velocity $v$ reduces
%\begin{figure}
\marginfig{
\begin{center}
{\mbox{\epsfxsize=50mm\epsfbox{../../images/PUBLICDOMAIN/maps/northseaTID.eps}}}\\
\end{center}
\caption[a]{Average tidal powers measured by \citet{Cartwright1980}.
}
\label{fig.TideLine2}
}%
%\end{figure}
(\eqref{eqv}).
% and the amplitude of tidal wave increases (as $1/d^{1/4}$, as we'll see).
For the present discussion we'll assume the depth is constant.
Energy flows from left to right at some rate.
How should this total tidal power be estimated?
And what's the {\em{maximum}\/} power that could be extracted?
One suggestion is to choose a cross-section and estimate the average
{\em{flux of kinetic energy}\/} across that plane, then
assert that this quantity represents the power that could be extracted.
This kinetic-energy-flux
method was used by consultants
Black and Veatch\nocite{BlackVeatch} to estimate the UK
resource. In our cartoon model, we can
compute the total power by
other means. We'll see that the kinetic-energy-flux answer is
too small by a significant factor.
The peak kinetic-energy flux at any section
is
\beq
K_{\rm BV} = \frac{1}{2} \rho A U^3 ,
\eeq
where $A$ is the cross-sectional area. (This is the
formula for kinetic energy flux, which
we encountered in \chref{ch.wind2}.)
The true total incident power is not equal to this kinetic-energy flux.
The true total incident power in a shallow-water wave
is a standard textbook calculation;
one way to get it is to find the total energy present in one wavelength
and divide by the period.
% ; another option is to imagine replacing a vertical
% section by an appropriately compliant
% piston and computing the average work done on the
% piston. I'll do the calculation both ways.
%
The total energy per wavelength is the sum of the potential energy and the kinetic energy.
The kinetic energy happens to be identical to the potential energy.
(This is a standard feature of almost all things that wobble, be they
masses on springs or children on swings.)
So to compute the total energy all we need to do is compute one
of the two -- the potential energy per wavelength, or the
kinetic energy per wavelength -- then double it.
% Let's go for the potential energy.
%
The potential energy of a wave (per wavelength and per unit width
of wavefront) is found by integration to be
\beq
\frac{1}{4} \rho g h^2 \lambda .
\eeq
So, doubling and dividing by the period,
the true power of this model shallow-water tidal wave is
\beq
\mbox{power} = \frac{1}{2}( \rho g h^2 \lambda) \times w / T
= \frac{1}{2} \rho g h^2 v \times w ,
\eeq
where $w$ is the width of the wavefront.
Substituting
% $A = w d$ and
$v=\sqrt{ g d }$,
\beq
\mbox{power}
= \rho g h^2 \sqrt{ g d } \times w /2
= \rho g^{3/2} \sqrt{ d } h^2 \times w /2 .
% = \rho g h^2 \sqrt{ g } \times A / \sqrt{d} ,
\label{eqP}
\eeq
Let's compare this power with
the kinetic-energy flux $K_{\rm BV}$.
Strikingly, the two expressions scale differently with the amplitude $h$.
Using the amplitude conversion relation (\ref{eqU}),
the crest velocity (\ref{eqv}), and $A = w d$,
we can re-express
the kinetic-energy flux
as
\beq
K_{\rm BV} = \frac{1}{2} \rho A U^3
= \frac{1}{2} \rho w d (v h/d)^3
% = \frac{1}{2} \rho w (\sqrt{ g d })^3 h^3 / d^2 .
= \rho \left( g^{3/2} / \sqrt{ d } \right) h^3 \times w/2 .
\label{eq.cubed}
\eeq
% *** OHB here ***
So the kinetic-energy-flux method suggests that the total
power of a shallow-water wave scales as amplitude {\em{cubed}\/} (\eqref{eq.cubed});
but the correct formula shows that the power scales as amplitude {\em{squared}\/}
(\eqref{eqP}).
The ratio is
\beq
\frac{ K_{\rm BV} }
{ \mbox{power} }
= \frac{ \rho w \left( g^{3/2} / \sqrt{ d } \right) h^3
}{ \rho g^{3/2} h^2 \sqrt{ d } w }
= \frac{ h
}{ d} .
\eeq
Because $h$ is usually much smaller than $d$ ($h$ is about 1\,m or 2\,m,
while $d$ is 100\,m or 10\,m),
estimates of tidal power resources that are
based on the kinetic-energy-flux method may be
{\em{much too small}}, at least in cases where this
shallow-water cartoon of tidal waves is appropriate.
Moreover, estimates based on the kinetic-energy-flux method
incorrectly assert that the total available power at springs (the biggest
tides) is eight times greater
than at neaps (the smallest tides),
assuming an amplitude ratio, springs to neaps, of two to one;
but the correct answer is that the total available power of a travelling wave
scales as its amplitude squared, so the springs-to-neaps
ratio of total-incoming-power is four to one.
% \section{Back to the shallow-water tidal wave model}
\subsection{Effect of shelving of sea bed, and Coriolis force}
If the depth $d$ decreases gradually and the width remains constant
such that there is minimal reflection or absorption of the incoming power,
then the power of the wave will remain constant.
This means
$\sqrt{d} h^2$ is a constant, so we
deduce that the height of the tide scales with depth
as
$h \sim 1/d^{1/4}$.
%% st kilda: springs = 2.8m, neaps = 1.3
%% shillay springs = 3.5m, neaps >= 1.5, maybe 1.8
%% /home/mackay/sustainable/refs/DTIAtlas> xv Z100.gif M100.gif
%\subsection{Application to the UK}
This is a crude model.
One neglected detail is the Coriolis effect.
The Coriolis force causes tidal crests and troughs to
tend to drive on the right -- for example,
going up the English Channel, the high tides are higher
and the low tides are lower on the French side of the
channel. By neglecting this effect I may have introduced
some error into the estimates.
% tide is like wind
\section{Power per unit area of tidal stream farms}
Imagine sticking underwater windmills on the sea-bed.
The flow of water will turn the windmills.
Because the density of water is roughly 1000 times that of
air, the power of water flow is 1000 times
greater than the power of wind at the same speed.
% (see \pref{eq.windpower1} for the equations).
% (equations \ref{eq.windpower1}--\ref{eq.windpower3}).
\begin{figure}[tp]\small
\figuredangle{
\begin{center}
\begin{tabular}{@{}c@{\,\,\,\,\,\,\,\,\,\,}c}
% \fullmoon \leftmoon \newmoon \rightmoon \fullmoon \\
\raisebox{1.162in}{\makebox[0in][l]{\footnotesize speed (m/s)\raisebox{-2.3mm}{%
\newmoon \hspace{24.13mm} \rightmoon \hspace{24.13mm} \fullmoon }}}
\ \ \ \ \ {\mbox{\epsfxsize=3.124in%
\mono{\epsfbox{../tide/mono/current.eps}}
{\epsfbox{../tide/current.eps}}%
}}%
&
\raisebox{1.162in}{\makebox[0in][l]{\footnotesize power (\Wmm)\raisebox{-2.3mm}{%
\hspace*{-7.6mm}\newmoon \hspace{54.3mm} \rightmoon }}}
\ \ \ \ \ {\mbox{\epsfxsize=3.124in\mono%
{\epsfbox{../tide/mono/power.eps}}%
{\epsfbox{../tide/power.eps}}%
}} \\[0.12in]
\multicolumn{1}{r}{\footnotesize time (days)} &
\multicolumn{1}{r}{\footnotesize time (days)} \\[-0.12in]
{\footnotesize (a)} & {\footnotesize (b)}
\\
\end{tabular}
\end{center}
}{
\caption[a]{(a) Tidal current over a 21-day period
% as a function of time
at a
% North Sea
location where the maximum current
at spring tide is 2.9\,knots (1.5\,m/s)
and the maximum current at neap tide is 1.8\,knots (0.9\,m/s).
(b) The power per unit sea-floor area over a nine-day period
extending from spring tides to neap tides.
The power peaks four times per day, and has a maximum of about
27\,\Wmm.
The average power of the tide farm
% oct.m 25.5W/m^2
is 6.4\,\Wmm.
}
\label{tidepoolNS}
}
\end{figure}
%
What power could tidal stream farms extract?
It depends crucially on whether or not we
can add up the power contributions
of tidefarms on {\em{adjacent}\/} pieces of sea-floor.
% densities per unit area
% sea-floor for many adjacent pieces of sea-floor.
For wind, this additivity assumption is
believed to work fine:
as long as the wind turbines are spaced a standard distance
apart from each other, the total power delivered by
10 adjacent {\windfarm}s is the sum of the
powers that each would deliver if it were alone.
{% begin troublesomepage hack
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
Does the same go for {\tidefarm}s?
Or do underwater windmills interfere with each other's
power extraction in a different way?
I don't think the answer to this question is known in general.
We can name two alternative assumptions, however,
and identify cartoon situations in which each assumption seems valid.
The
``\ind{tide is like wind}'' assumption says that you can put
tide-turbines
all over the sea-bed, spaced about 5 diameters apart from each other,
and they won't interfere with each other, no matter how much of the
sea-bed you cover with such {\tidefarm}s.
% This assumption seems to me
% to be valid if the heights of the turbines are small compared to the
% water depth. I think it might be valid even for tall turbines, but
% I'm not sure.
The ``\ind{you can have only one row}'' assumption, in contrast,
asserts that the maximum
power extractable in a region is the power that would be delivered by
a {\em{single}\/} row of turbines facing the flow.
A situation where this assumption is correct is the special case of
a hydroelectric dam: if the water from the dam passes through a single
well-designed turbine, there's no point putting any more turbines behind that one.
You can't get 100 times more power by putting 99 more
turbines downstream from the first.
The oomph gets extracted by the first one, and
there isn't any more oomph left for the others.
The ``\ind{you can have only one row}'' assumption is the right assumption
for estimating the extractable power in a place where
water flows through a narrow channel
from approximately stationary water at one height
into another body of water at a lower height.
(This case is analysed by \citet{Garrett05,Garrett07}.)
% -- from the Atlantic into the Mediterranean through the Strait of Gibraltar, for
% example.
I'm now going to nail my colours to a mast. I think that in many places
round the British Isles, the ``\ind{tide is like wind}'' assumption
is a good approximation.
Perhaps some spots have some of the character of a narrow channel.
% the Straits of Gibraltar.
In those spots, my estimates may be over-estimates.
Let's assume that
the rules for laying out a sensible {\tidefarm} will be similar to
those for {\windfarm}s, and that the efficiency of the tidemills
will be like that of the best windmills, about $1/2$.
We can then steal the formula for the power of a {\windfarm} (per unit land area)
from \pref{eq.windpower5}.
The power per unit sea-floor area is
\beqan
\frac{ \mbox{power per tidemill}}
{ \mbox{area per tidemill} }
%& =& \frac{ \frac{1}{2} \rho v^3 \frac{\pi}{8} d^2 }
% { (5 d)^2 }
%\label{eq.tidepower4}
%\\
& = & \frac{\pi}{200} \frac{1}{2} \rho U^3 .
\label{eq.tidepower5}
\eeqan
Using this formula, table \ref{tidetable} shows this {\tidefarm} power
for a few tidal currents.
\amargintab{c}{
\begin{center}
% 1 knot = 0.514444444444444444 m/s
\begin{tabular}{ccc} \toprule
\multicolumn{2}{c}{$U$} & {\tidefarm} \\
(m/s) & (knots) & power\\
& & (\Wmm) \\ \midrule
0.5 & 1 & 1 \\
1 & 2 & 8 \\
2 & 4 & 60 \\ % 62.8
3 & 6 & 200 \\ % 212
4 & 8 & 500 \\ % 502
5 & 10 % 9.72
& 1000 \\ % 981.7
\bottomrule
\end{tabular}
\end{center}
%}{
\caption[a]{{\Tidefarm} power per unit area
(in watts per square metre
of sea-floor) as a function of flow speed $U$.
(1 knot = 1 nautical mile per hour = 0.514\,m/s.)
The power per unit area is computed using
$\frac{\pi}{200} \frac{1}{2} \rho U^3$
(\protect\eqref{eq.tidepower5}).
}
\label{tidetable}
}%
Now, what are typical tidal currents?
Tidal charts usually give the currents
associated with the tides with the largest range (called spring tides)
and the tides with the smallest range (called neap tides).
Spring tides occur shortly after each full moon and each new moon.
Neap tides occur shortly after the first and third quarters of the moon.
The power of a tide farm would vary throughout the day
in a completely predictable manner.
\Figref{tidepoolNS} illustrates the variation
of power per unit area of a {\tidefarm} with a maximum current
of 1.5\,m/s. The average power per unit area of this {\tidefarm}
would be 6.4\,\Wmm.
There are many places around the British Isles where the power per unit
area of \tidefarm\ would be
% sea-floor is
$6\,\Wmm$ or more.
This power per unit area is similar to our estimates of
the powers per unit area of {\windfarm}s (2--3\,\Wmm)
and of photovoltaic solar farms (5--10\,\Wmm).
% And about the same as our estimate of the power density of
% an off-shore {\windfarm} ($5\W/\m^2$).
% Tide power is not to be sneezed at!
% How would it add up, if we assume that there are no economic
% obstacles to the exploitation of tidal power at all the
% hot spots around the UK?
We'll now use this ``tide farms are like {\windfarm}s'' theory
to estimate the extractable power from tidal streams in promising
regions around
the British Isles. As a sanity check, we'll also
work out the total tidal power crossing each of these regions,
using the ``power of tidal waves'' theory,
to check our {\tidefarm}'s estimated power isn't bigger than the total power
available.
\label{maintide}The main
locations around the British Isles where tidal currents are large are
shown in \figref{tideUK}.
\begin{figure}
\figuremarginwidecapab{
%\figuremargin{
\begin{center}\vspace*{-2.5mm}
\mbox{\epsfxsize=2.72in\epsfbox{../../images/PUBLICDOMAIN/Tides.eps}}
\end{center}
}{
\caption[a]{Regions around the British Isles where
peak tidal flows exceed 1\,m/s.
The six darkly-coloured regions are included
in table \protect\ref{tab.tide}:
\begin{enumerate}
\item {} \
the English channel (south of the Isle of Wight);
\item {} \
the Bristol channel;
\item {} \
to the north of Anglesey;
\item {} \
to the north of the Isle of Man;
\item {} \
between Northern Ireland, the Mull of Kintyre, and Islay; and
\item {} \ the
Pentland Firth (between Orkney and mainland Scotland),
and within the Orkneys.
\end{enumerate}
There are also enormous
currents around the Channel Islands, but they are not governed by
the UK\@. Runner-up regions include
the North Sea, from the Thames (London) to the Wash (Kings Lynn).
The contours show water depths greater than 100\,m.
Tidal data are from Reed's Nautical
Almanac and DTI\ Atlas of UK Marine Renewable
Energy Resources (2004).
}
\label{tideUK}
}{90mm}{80mm}
\end{figure}
\begin{table}
\figuremargin{\small
\begin{tabular}{@{}c@{\,}c@{}}
\begin{tabular}{cc@{\,\,\,}r@{\,\,\,}crr}\toprule
{Region} & \multicolumn{2}{c}{$U$}%{peak current}
&
power & area & average \\
& \multicolumn{2}{c}{(knots)} &
density & & power \\
& N & S &
(\Wmm) & (km$^2$) & (kWh/d/p) \\ \midrule
1
%English Channel (South of Isle of Wight)
%%% power-density area power
& 1.7 & 3.1 & 7 & 400 & \OliveGreen{1.1} \\ % was 2.82
2
% Bristol Channel
& 1.8 & 3.2 & 8 & 350 & \OliveGreen{1.1} \\ % 2.37
3
% Irish Sea (near Anglesey)
& 1.3 & 2.3 & 2.9 & 1000 & \OliveGreen{1.2} \\ % 1.178
4
% North of Isle of Man
& 1.7 & 3.4 & 9 & 400 & \OliveGreen{1.4} \\ % 1.40
% Irish Sea (Ireland) & 2.0 & 3.0 & 7.5 & 1000 & 3.0$^*$ \\ % 3.00
5
% Between Northern Ireland, Islay and Mull of Kintyre
&
1.7 & 3.1 & 7 & 300 & \OliveGreen{0.8} \\ % 2.82
%% the sea area of PF is definitely 100 km^2 but let's say 50km^2. was 1.4, now 7.0, now 3.5
6
% Pentland Firth
& 5.0 & 9.0 & 170 & 50 & \OliveGreen{3.5} \\ % 5.57 using oct.m Aka 8.5GW
% North Sea near Cromer
% % Kings Lynn 3.5+1.7= 5.2
% & 1.2 & 2.2 & 2.5 & 1000 & 1.0 \\ % 4.02 using oct.m
% Southern North Sea & 1.1 &1.9 & 1.7 & 1000 & 0.7 \\ % 0.676
\midrule
\multicolumn{3}{l}{Total} & & & \OliveGreen{{\bf 9}} \\ % 16.67 including Ireland part
\bottomrule
\end{tabular}
&
\begin{tabular}{cccc}\toprule
%\multicolumn{2}{c}{Region} &
& & \multicolumn{2}{c}{raw power} \\%& {\tidefarm}\\
%& &
$d$% depth
&
$w$ %width
& N & S \\%& estimate\\
%& &
(m) & (km) & \multicolumn{2}{c}{(kWh/d/p)} \\
\midrule
%% B+V: depth 30-40 or >40 Best bit has depth 30m. width 13km
%1&
%English Channel (South of Isle of Wight)
% &
30 & 30 & 2.3 & 7.8 \\%& 1.1 \\ %%% CAUTION: my est is 25% of TOTAL was 2.8,now 1.1
%% B+V: depth 25-40 / 30-40
%2&
%Bristol Channel
%&
30 & 17 & 1.5 & 4.7 \\%& 1.1 \\ %%% CAUTION: my est is 50% of TOTAL was 2.4 now 1.2
%% > 40m aka Carmel Head depth=35m width=7.5km
%3&
%Irish Sea (near Anglesey)
% &
50 & 30 & 3.0& 9.3 \\%& 1.2 \\ %%% looks fine
%% much of it is >40
%4&
% North of Isle of Man
%&
30 &20 & 1.5& 6.3 \\% & 1.4 \\ %%% looks fine
%% Mainly >40m page 27 says depth=29/30m width=7.3km BUT there is a height node at Islay so mistrust
%5&
% Between Northern Ireland, Islay and Mull of Kintyre
%&
40 & 10 & 1.2 & 4.0 \\%& 0.8 \\ %%% CAUTION: my est is 100% of TOTAL was 2.8, now 0.8
%6&
% Pentland Firth
%&
70 & 10 & 24 & 78 \\%& 3.5 \\ %%% OK
\midrule
\,
% \multicolumn{2}{l}{Total} & & & & & {\bf 9}
\\ %
\bottomrule
\end{tabular}
\\
(a)&(b)\\
\end{tabular}
}{
\caption[a]{(a) Tidal power estimates assuming that stream farms are like {\windfarm}s.
The power density is the average power per unit area of sea floor.
%% Total power is divided by the population of UK.
% (*) The estimated Irish Sea (Ireland) production
% would be in the territorial waters of Ireland.
The six regions are indicated in \protect\figref{tideUK}.
% This table lists them clockwise starting from London.
N = Neaps.
S = Springs.
(b) For comparison, this table
% compares the \tidefarm\ estimates
% of extractable power of \tabref{tab.tide}(a) with
shows the raw incoming power
estimated using \eqref{eqRawPo} (\pref{eqRawPo}).
% on \pref{sec.powerT}.
% The six regions are indicated in \protect\figref{tideUK}.
% This table lists them clockwise starting from London.
}
\label{tab.tide}\label{tab.tide2}
}
\end{table}
%% Of all the estimates in this book, this estimate of
% the tidal resource of Britain is the one I am least certain
% about.
I estimated\label{pSteal1} the typical peak currents at six locations
with large currents by looking at
tidal charts in {\tem{Reed's Nautical Almanac}}. (These estimates
could easily be off by 30\%.)
Have I over-estimated or under-estimated
the area of each region? I haven't surveyed the sea floor
so I don't know if some regions might be unsuitable in some
way -- too deep, or too shallow, or too tricky to build on.
% I've included only six small regions with large
% currents. Perhaps I should also have included an
% estimate for the power from the much larger regions
% with small currents.
% according to my oct estimate of the backup region
% in the north sea of area 10,000 km^2 with currents (0.6kn, 1kn)
% we'd get an extra 1 from that.
% I can imagine my estimate might be off by a factor of four
% in either direction.
Admitting all these uncertainties, I arrive at an estimated
total power of \OliveGreen{9\,kWh/d per person} from tidal
stream-farms.
% ; plus another 2\,kWh/d per person from tidal lagoons and tidal barrages.
This corresponds to 9\% of the raw incoming power
mentioned on \pref{ptide100}, 100\,kWh per day per person.
% The total power crossing the lines in \figref{fig.TideLine}
% has been measured; on average it amounts to 100\,kWh per day per person.
(The extraction of 1.1\,kWh/d/p in the Bristol channel, region 2,
might conflict with power generation by the Severn barrage; it would depend on
whether the {\tidefarm} significantly {\em{adds}\/} to the existing natural
friction created by the channel,
or {\em{replaces}\/} it.)
%\subsection{Double-check}
% In table \ref{} I use
% the total power per unit length $\rho g^{3/2} \sqrt{ d } h^2$
%% U = sqrt(gd) h/d. U = sqrt(g) h/sqrt(d). h = U sqrt(d)/sqrt(g)
% $= \rho g^{3/2} \sqrt{ d } U^2 d/g$
% $= \rho g^{1/2} { d }^{3/2} U^2$
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Power(d,U) = 1000 * sqrt(9.81) * d**(1.5) * (0.51444*U)**2
% power in W/m. w is in km, so mul by 1000 for m, then divide by 1000 for kW
% M(U,d,w) = w*Power( d,U ) * 24.0 / 60e6
% 1 knot = 0.514444444444444444 m/s
%%% almost all these large areas offer 1.5-2.5 m/s only.
% _tide.tex contains another version of this table
\section{Estimating the tidal resource via bottom friction}
Another way to estimate the power available from tide is
to compute how much power is already dissipated by friction on
the sea floor.
A coating of turbines placed just above the sea floor
could act as a substitute bottom, exerting roughly
the same drag
on the passing water as the sea floor used to exert,
and extracting roughly the same
amount of power as friction used to dissipate,
without significantly altering the
tidal flows.
So, what's the power dissipated by ``bottom friction''?
Unfortunately, there isn't a straightforward
model of bottom friction. It depends on the roughness of the
sea bed and the material that the bed is made from -- and even given
this information, the correct formula to use is not settled.
One widely used model says that
the magnitude of the stress (force per unit area) is
$R_1 \rho U^2$, where $U$ is the average flow velocity
and $R_1$ is a dimensionless quantity called the shear
friction coefficient.
We can estimate the power dissipated per unit area
by multiplying the
stress by the velocity.
Table \ref{tidefrictiontable} shows the power dissipated in friction,
$R_1\rho U^3$, assuming $R_1 = 0.01$ or $R_1 = 0.003$.
% (Add citations.)
% see _tide.tex
\begin{table}
\figuremargin{
\begin{center}
% 1 knot = 0.514444444444444444 m/s
\begin{tabular}{ccrrr} \toprule
$v$ & $v$ & \multicolumn{2}{c}{Friction power} & {\tidefarm} power \\
(m/s) & (knots) & \multicolumn{2}{c}{density (\Wmm)} & density \\
& & $R_1=0.01$ & $R_1=0.003$ & (\Wmm) \\ \midrule
0.5 & 1 & 1.25 & 0.4 & 1 \\
1 & 2 & 10 & 3 & 8 \\
2 & 4 & 80 & 24 & 60 \\ % 62.8
3 & 6 & 270 & 80 & 200 \\ % 212
4 & 8 & 640 & 190 & 500 \\ % 502
5 & 10 % 9.72
& 1250 & 375 & 1000 \\ % 981.7
\bottomrule
\end{tabular}
\end{center}
}{
\caption[a]{Friction power per unit area $R_1\rho U^3$ (in watts per square metre
of sea-floor) as a function of flow speed, assuming $R_1 = 0.01$
or $0.003$. \citet{Flather1976} uses $R_1=0.0025$--$0.003$;
\citet{Taylor1920} uses 0.002.
% (I don't have a factor of $1/2$ in the formula.)
(1 knot = 1 nautical mile per hour = 0.514\,m/s.)
The final column shows the {\tidefarm} power estimated in \tabref{tidetable}.
For further reading see \cite{Kowalik04}, \cite{Sleath}.
}
\label{tidefrictiontable}
}
\end{table}
For values of the shear
friction coefficient in this range, the
friction power is very similar to the estimated power that a tide farm
would deliver. This is good news, because it suggests that
planting a forest of underwater windmills on the sea-bottom,
spaced five diameters apart, won't radically alter the
flow.
% in the region.
The natural friction already has an
effect that is in the same ballpark.
%I disagree somewhat with the friction coefficient
%that Stephen uses in his calculations. I have a paper where he uses a
%"friction value" of 0.017, multiplied by an area of 23 x 10 km^2 and a
%velocity of 3 m/s to arrive at a power dissipation of 54 GW\@. In contrast
%to this I have an oceanography paper which gives C_d = 0.0026, and I am
%informed by an oceanographer colleague that 0.0026 is sensible.
}% end troublesoem page hack
\section{Tidal pools with pumping}
``The pumping trick''
artificially increases the amplitude of the tides
in a tidal pool so as to amplify the power obtained.
The energy cost of pumping {\em{in}\/} extra water at high tide is
repaid with interest when the same water is let {{out}} at low tide;
similarly, extra water can be pumped {\em{out}\/}
at low tide, then let back in at high tide.
The pumping trick is sometimes used at La Rance, boosting its
net power generation by about 10\%
% 494 GWh net gernated in 1984, when pumping was happening 22.6% of time
% and genreating was happening 73.4% + 4% of the time
% total generated was 609 GWh page 90 of Novak
\citep{WilsonBallsTide}.
Let's work out the theoretical limit for this technology.
% Two-way generation in CHina: there's only one big plant, at Jiangxia, which
% generates 12 GWh/y
% see also storage.tex where same calcns are done
I'll assume that generation has an efficiency of $\epsilon_{\rm{g}} = 0.9$
and that pumping has an efficiency of $\epsilon_{\rm{p}} = 0.85$.
% (These figures are based on the pumped storage system at Dinorwig.)
% , whose round-trip efficiency is about 75\%.)
Let the tidal range be $2h$.
I'll assume for simplicity that the prices of buying and selling electricity
are the same at all times,
% high tide and low tide,
so that the optimal height boost $b$ to which the pool is pumped above
high water is
given by (marginal cost of extra pumping = marginal return of extra water):
\[
b / \epsilon_{\rm{p}} = \epsilon_{\rm{g}} ( b + 2h ) .
\]
Defining the round-trip efficiency
$\epsilon = \epsilon_{\rm{g}}\epsilon_{\rm{p}}$, we have
\[
b = 2h \frac{\epsilon }{1- \epsilon } .
\]
For example, with a tidal range of $2h=4\,\m$, and a round-trip efficiency
of $\epsilon=76\%$, the optimal boost is $b=13\,\m$.
This is the maximum height to which pumping can be justified if the
price of electricity is constant.
Let's assume the complementary trick is used at low tide. (This requires
the basin to have a vertical range of 30\,m!)
The delivered power per unit area is then
\[
\left. \left( \frac{1}{2} \rho g \epsilon_{\rm{g}} ( b + 2h )^2
- \frac{1}{2} \rho g \frac{1}{\epsilon_{\rm{p}}} b^2 \right) \right/ T ,
\]
where $T$ is the time from high tide to low tide.
We can express this as the maximum possible
power per unit area without pumping,
$\epsilon_{\rm{g}} { 2 \rho g h^2}/{ T }$,
scaled up by a boost factor
\[
% \left( \frac{1}{1- \epsilon} \right)^2
%- \frac{1}{\epsilon} \left( \frac{\epsilon}{1- \epsilon} \right)^2
\left( \frac{1}{1- \epsilon} \right),
\]
which is roughly a factor of 4.
\begin{table}\figuremargin{
%% see figs/tide.gnu
\begin{center}
\begin{tabular}{cccc}\toprule
tidal amplitude & optimal boost & power & power \\
(half-range) $h$ & height $b$ & with pumping & without pumping \\
(m) & (m) & (\Wmm) & (\Wmm) \\
\midrule
% 0.5 & 3.3 & 0.9 & 0.2\\
1.0 & 6.5 & 3.5 & 0.8\\
2.0 & 13\phantom{.01} & 14 & 3.3\\
3.0 & 20\phantom{.02} & 31 & 7.4\\
4.0 & 26\phantom{.02} & 56 & 13 \\
%0.5 & 3.255 & 0.8696 & 0.2
%1.0 & 6.510 & 3.4787 & 0.8
%2.0 & 13.02 & 13.914 & 3.3
%3.0 & 19.53 & 31.308 & 7.4
%4.0 & 26.04 & 55.659 & 13 \\
\bottomrule
\end{tabular}
\end{center}
}{\caption[a]{Theoretical power per unit area from tidal
power using the pumping trick,
assuming no constraint on the height of the basin's walls.}\label{figTidePump1}
}
\end{table}
\Tabref{figTidePump1} shows the theoretical power per unit area
that pumping could deliver.
Unfortunately, this pumping trick will rarely be exploited
to the full because of the economics of basin construction:
full exploitation of pumping requires the total height of the pool
to be roughly 4 times the tidal range, and increases the delivered
power four-fold. But the amount of material in a sea-wall of height $H$ scales
as $H^2$, so the cost of constructing
a wall four times as high will be
more than four times as big. Extra cash would probably be better spent on
enlarging a tidal pool horizontally rather than vertically.
The pumping trick can nevertheless be used for free on any
day when
the range of natural tides is smaller than the maximum range:
the water level at high tide can be pumped up to the maximum.
Table \ref{tab.Pump2} gives the power delivered if the boost height
is set to $h$, that is, the range in the pool is just double the external range.
\begin{table}\figuremargin{
\begin{center}
\begin{tabular}{cccc}\toprule
tidal amplitude & boost height & power & power \\
(half-range) $h$ & $b$ & with pumping & without pumping \\
(m) & (m) & (\Wmm) & (\Wmm) \\ \midrule
% 0.5 &0.5 & 0.4 &0.2\\
1.0 &1.0 & 1.6 &0.8\\
2.0 &2.0 & 6.3 &3.3\\
3.0 &3.0 & 14\phantom{.01} &7.4\\
4.0 &4.0 & 25\phantom{.02} &13\phantom{.01} \\
%0.5 &0.5 & 0.39305 &0.2\\
%1.0 &1.0 & 1.57221 &0.8\\
%2.0 &2.0 & 6.28887 &3.3\\
%3.0 &3.0 & 14.1499 &7.4\\
%4.0 &4.0 & 25.1554 &13\\
\bottomrule
\end{tabular}
\end{center}
}{
\caption[a]{Power per unit area offered by the pumping trick,
assuming the boost height is constrained to be the same as the
tidal amplitude.
This assumption applies, for example, at neap tides, if the
pumping pushes the tidal range up to the springs range.
}\label{tab.Pump2}
}
\end{table}
A doubling of vertical range
is easy at neap tides, since neap tides are typically
about half as high as spring tides.
Pumping the pool at neaps so that the full springs range
is used thus allows neap tides to deliver roughly twice as much
power as they would offer without pumping. So a system with pumping
would show two-weekly variations in power of just a factor
of 2 instead of 4.
\subsection{Getting ``always-on'' tidal
power by using two basins}
Here's a neat idea:\label{pHaishan}
have \index{tidal power!two basins}two basins, one of which is the ``full'' basin
and one the ``empty'' basin; every high tide, the full basin is topped up;
every low tide, the empty basin is emptied.
These toppings-up and emptyings could be done
either passively through sluices, or
actively by pumps (using the trick mentioned
above).
Whenever power is required, water is allowed to flow
from the full basin to the empty basin, or (better in power terms)
between one of the basins and the sea.
% The power per unit area is the same
%%%%%%%%%%%%%% as that of the single-basin tidal barrage;
The capital cost of a two-basin scheme may be bigger because
of the need for extra walls;
the big win is that power is available all the time,
so the facility can follow demand.
% http://www.fibrowatt.com/tidal-power.html
% http://cat.inist.fr/?aModele=afficheN&cpsidt=9408982
We can use power generated from the empty basin to pump
extra water into the full basin at high tide,
and similarly use power from the full basin to pump down the
empty basin at low tide. This self-pumping
would boost the total power delivered by the facility
without ever needing to buy energy from the grid.
It's a delightful feature of a two-pool solution that
the optimal time to {\em{pump}\/} water into the high pool is high tide, which
is also the optimal time to {\em{generate}\/} power from the low pool.
Similarly, low tide is the perfect time to pump down the low pool,
and it's the perfect time to generate power from the high pool.
In a simple simulation, I've found that a two-lagoon
system in a location with a natural tidal range of 4\,m
can, with an appropriate pumping schedule, deliver a {\em{steady}\/}
power of 4.5\,\Wmm\
\citep{MacKayLagoons}. One lagoon's water level is always kept
above mean sea-level; the other lagoon's level is always kept below
mean sea-level.
This power per unit area of 4.5\,\Wmm\ is 50\% bigger than
the maximum possible average
power per unit area of an ordinary tide-pool in the same location (3\,\Wmm).
The steady power of the lagoon system would be more valuable than
the intermittent and less-flexible power from the ordinary tide-pool.
A two-basin system could also function as a pumped-storage
facility.
% I'll come back to this in chapter \ref{ch.storage}.
% (\pref{pTESS})
%{\em (Perhaps move all this material to one place). }
\begin{figure}
\figuremargin{\small
\begin{center}
\begin{tabular}{cc}
{\mbox{\epsfxsize=52mm\epsfbox{figs/TideStore.eps}}} &
{\mbox{\epsfxsize=52mm\epsfbox{figs/TideStore2.eps}}} \\
(a)&(b)\\
\end{tabular}
\end{center}
}{
\caption[a]{Different ways to use the tidal pumping trick.
Two lagoons are located at sea-level.
(a) One simple way of using two lagoons
is to label one the high pool and the other the low pool; when
the surrounding sea level is near to high tide, let
water into the high pool, or actively pump it in (using electricity
from other sources);
and similarly, when the sea level is near to low tide, empty
the low pool, either passively or by active pumping;
then whenever power is sufficiently valuable, generate power on
demand by letting water from the high pool to the low pool.
(b)
Another arrangement that might deliver more power per unit area
has no flow of water between the two lagoons.
While one lagoon is being pumped full or pumped
empty, the other lagoon can deliver steady, demand-following
power to the grid.
Pumping may be powered by bursty sources such as wind, by spare power
from the grid (say, nuclear
power stations), or by the other half of the facility,
using one lagoon's power to pump the other lagoon up or down.
% to a greater height.
}\label{fig.TESS}
}
\end{figure}
\small
\section{Notes}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{Turbine90}]
{\nqs{Efficiency of 90\%\ldots}}
Turbines are about 90\%
efficient for heads of 3.7\,m or more.
\cite{BakerSwansea}.
% December
\item[\npageref{pHaishan}]
{\nqs{Getting ``always-on'' tidal
power by using two basins.}}
% There is a two-basin tidal power plant at \ind{Haishan}.
% \subsection{Haishan}
There is a two-basin tidal power plant
at \ind{Haishan}, Maoyan Island, \ind{China}. A single generator
located between the two basins, as shown in \figref{fig.TESS}(a),
% can generate up to 75\,kW,
delivers power continuously, and generates 39\,kW on average.
% average power =
\tinyurl{2bqapk}{http://wwwphys.murdoch.edu.au/rise/reslab/resfiles/tidal/text.html}.
% The Haishan TPP is noteworthy as it is the only linked-basins plant in existence in the world  a plant featuring a high and a low-basin with the power plant in between these two basins, generating energy from water flowing from the high into the low-basin. The plant is located on Maoyan Island in Zhejiang province where it serves an isolated community of 760 families. The plant was designed for two 75kW units of which only one was installed and commissioned in 1975. This unit operated continuously. The energy was used partly to pump fresh water for domestic and irrigation use into the community reservoir. The plant has since been upgraded to an installed capacity of 0.25MW, producing 0.34GWh per year (Wilmington Media Ltd, 2004).
%% authors: Katrina O'Mara and Mark Rayner, with assistance from Philip Jennings (Murdoch University) in June 1999. Edited and Updated by Katrina Lyon in June 2004 and Mark McHenry in January 2006.
%% see also
%% http://www.waterpowermagazine.com/story.asp?storyCode=2022354
%% http://www.waterpowermagazine.com/story.asp?storyCode=2022354
%% recommends using a flow-through layout -- in at one end, out at other.
\item[Further reading:]
\cite{ShawWatsonTrading,Blunden,CharlierTideArticle,TidalStreamCharlier}.
For further reading on
bottom friction and variation of flow with depth, see \cite{Sleath}.
For more on the estimation of the UK tidal
resource,\index{tide!UK resource}
see \citet{MacKayUnderestimationTide}.
For more on \ind{tidal lagoon}s,
see \citet{MacKayLagoons}.
\end{notelist}
\normalsize
% \section{Notes}
% Area behind the Bristol barrage is 480\,km$^2$.
% So with average output of 2\,GW, it would indeed deliver 4\,\Wmm.
%% Actually 185 sq mi from the FOE site.
%% 4.536e+8 m² / 4.536e+4 hectares / 453.6 km² / 4.882e+9 ft² / 1.121e+5 acres / 175.1 mile²
%% measured by me
%% http://www.acme.com/planimeter/
\rset\chapter{\rcol{Stuff II}}
\label{ch.stuff2}
\section{Imported energy}
Dieter Helm\index{Helm, Dieter} and his colleagues estimated the footprint of each
\marginfig{
\begin{center}
\epsfxsize=53mm\lowres{\epsfbox{../../images/CastingSteelS.eps}}%
{\epsfbox{../../images/CastingSteel.eps}}
\end{center}
%}{
\caption[a]{
Continuous casting of steel strands at
Korea Iron and Steel Company.
% KISCO, used for making concrete reinforcement bars.
% Casting steel
}
%\end{figure}
}%
pound's worth of \ind{imports} from country X using the average
\ind{carbon intensity} of country X's economy (that is, the ratio of their carbon
emissions to their gross domestic product). They concluded that
the embodied carbon in imports to Britain (which should arguably be
added to Britain's official carbon footprint of
11 \tonnes\ \COOe\ per year per person) is roughly 16
\tonnes\ \COOe\ per year per person.
A subsequent, more detailed study commissioned by DEFRA
estimated that the embodied carbon
in imports is smaller, but still very significant:
about 6.2 \tonnes\ \COOe\ per
year per person.\nlabel{pDefraCarbonSEI}
In energy terms, 6 \tonnes\ \COOe\ per year is something
like 60\,kWh/d.
Here, let's see if we can reproduce these conclusions
in a different way, using the weights of the imports.
\Figref{fig.imports21} shows Britain's imports in the year 2006 in
three ways: on the left, the total {\em{value}\/} of the imports is broken
down by the country of origin. In the middle, the same total financial
value is
broken down by the type of stuff imported, using the categories of HM
Revenue and Customs. On the right, all maritime imports to Britain
are shown by {\em{weight}\/} and broken down by the categories used by the
Department for Transport, which doesn't
care whether something is leather
or tobacco -- it keeps track of how heavy stuff is, whether it is
dry or liquid, and whether the stuff arrived in a container or a
lorry.
\begin{figure}
\figuremargin{
\begin{center}
{\raisebox{-5mm}[\textheight]{\epsfbox{metapost/imports.21}}}\\
\end{center}
}{
\caption[a]{Imports of stuff to the UK,\index{data!imports} 2006.}\label{fig.imports21}
}
\end{figure}
The energy cost of the imported fuels (top right) {\em{is}\/}
included in the standard accounts of British energy consumption; the
energy costs of all the other imports are not. For most materials,
the embodied energy per unit weight is greater than or equal to
10\,kWh per kg -- the same as the energy per unit weight of fossil
fuels. This is true of all metals and alloys, all polymers and
composites, most \ind{paper} products, and many ceramics, for example. The
exceptions are raw materials like ores; porous ceramics such as
concrete, brick, and porcelain, whose energy cost is 10 times lower;
wood and some rubbers; and glasses, whose energy cost is a whisker lower than
10\,kWh per kg.
\tinyurlb{r22oz}{http://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/energy-cost/NS6Chart.html}
We can thus roughly estimate the energy footprint of our imports simply from
the weight of their manufactured materials, if we exclude things
like ores and wood. Given the crudity of the data with which we are
working, we will surely slip up and inadvertently include some things
made of wood and glass, but hopefully such slips will be balanced by
our underestimation of the energy content of most of the metals and
plastics and more complex goods, many of which have an embodied
energy of not 10 but 30\,kWh per kg, or even more.
For this calculation I'll take from the
right-hand column in \figref{fig.imports21}
the iron and steel products, the dry bulk products,
the containerized \ind{freight} and
the ``other freight,'' which total
98\,million \tonnes\ per year.
I'm leaving the vehicles to one side for a moment.
I subtract from this
an estimated 25\,million \tonnes\ of food
which is presumably lurking in the
``other freight'' category
(34 million \tonnes\ of food were imported in 2006),
leaving 73 million \tons.
% source: http://statistics.defra.gov.uk/esg/datasets/webindig.xls
% on page: http://statistics.defra.gov.uk/esg/index/list.asp?i_id=059
% there is good stuff here too:
%% http://statistics.defra.gov.uk/esg/publications/auk/2005/excel.asp
% I found a doc that says
% 12.2 million tonnes of food are imported each year (from Europe?).
%% http://www.bestruralretailer.co.uk/facts-and-statistics/
%% says 20 M
Converting 73\,million \tonnes\ to energy using the exchange
rate suggested above, and sharing between
60 million people, we estimate
that those imports have an embodied energy
of
%\[
%\frac{ 87\,\mbox{Mt/y} \times 10\,\kWh/kg }
% { 60\,\mbox{M people} }
%\] 870000/60 / 365 = 39.726
%\] 730000/60 / 365 = 39.726
33\,kWh/d per person.
For the cars, we can hand-wave a little less,
because we know a little more:
the number of imported vehicles in 2006 was
2.4\,million. If we take the embodied energy per
car to be 76\,000\,kWh (a number we picked up on
\pref{pNewCar}) then
these imported cars have an embodied
energy of 8\,kWh/d per person.\index{embodied energy!car}
%76000*2.4e6/60e6 / 365
%ans = 8.3288
I left the ``liquid bulk products''
out of these estimates
because I am not sure what sort of products
they are. If they are actually liquid chemicals
then their contribution might be significant.
We've arrived at a total
estimate of 41\,kWh/d per person for
the embodied energy of imports -- definitely
in the same ballpark as the estimate of
Dieter Helm and his colleagues.
{% begin troublesomepage hack
% this should be *before* the start of troublesome page
\renewcommand{\floatpagefraction}{0.8}
I suspect that 41\,kWh/d
per person may be an underestimate
because the energy intensity we assumed
(10\,kWh per kg) is too low for most
forms of manufactured goods such as machinery
or electrical equipment.
However, without knowing the weights
of all the import categories, this
is the best estimate I can make for now.
% Car: cost of manufacture is about 10\% of the cost of using?
\marginfig{
\begin{center}
\epsfxsize=53mm%
\lowres{\epsfbox{../../images/NiobiumOpenCastMineBrazil.jpg.S.eps}}%
{\epsfbox{../../images/NiobiumOpenCastMineBrazil.eps}}
\end{center}
%}{
\caption[a]{
Niobium open cast mine, Brazil.
}
%\end{figure}
}
% UK imports from China rose by 10% nearing 6.5 million tonnes
% http://news.bbc.co.uk/1/low/sci/tech/7028573.stm
% 14% of China's carbon dioxide emissions were accounted for by exports to the US.
%Life-cycle analysis databases:
%\myurl{http://www.ecobalance.com/uk_deam01_02.php}
% crap, didn't help me.
\section{Lifecycle analysis for buildings}
%\myurl{http://www.greenhouse.gov.au/yourhome/technical/fs31.htm}
% moved to http://www.yourhome.gov.au/technical/pubs/fs52.pdf
Tables \ref{tabEmbMat} and \ref{tabEmbMat2}
show estimates of the {\dem\ind{Process Energy Requirement}\/}
of building materials and building constructions.\index{lifecycle analysis}
This includes the energy used in transporting the raw materials
to the factory but not energy used to transport the final product to the building site.
\begin{table}
\figuremargin{
\begin{center}
\begin{tabular}{lrr} \toprule
Material &\multicolumn{2}{c}{Embodied energy} \\
& (MJ/kg) & (kWh/kg)\\
\midrule
kiln-dried sawn \ind{softwood} & 3.4 & 0.94 \\
kiln-dried sawn \ind{hardwood} & 2.0 & 0.56 \\
air dried sawn hardwood & 0.5 & 0.14 \\
\ind{hardboard} & 24.2 & 6.7 \\
\ind{particleboard} & 8.0 & 2.2 \\
% bath say sawn hardwood is 7.8 MJ/kg
% and particleboard is 23 MJ/kg
\ind{MDF} & 11.3 & 3.1 \\
\ind{plywood} & 10.4 & 2.9 \\
glue-laminated \ind{timber} & 11 & 3.0 \\
laminated veneer \ind{lumber}\index{laminated wood}
& 11 & 3.0 \\
\ind{straw} & 0.24 & 0.07 \\
\midrule
stabilised \ind{earth} & 0.7 & 0.19 \\
imported dimension \ind{granite} & 13.9 & 3.9 \\
local dimension granite & 5.9 & 1.6 \\
\ind{gypsum} \ind{plaster} & 2.9 & 0.8 \\
\ind{plasterboard} & 4.4 & 1.2 \\
fibre \ind{cement} & 4.8 & 1.3 \\
cement & 5.6 & 1.6 \\
in situ \ind{concrete} & 1.9 & 0.53 \\
precast steam-cured concrete & 2.0 & 0.56 \\
precast tilt-up concrete & 1.9 & 0.53 \\
\ind{clay} \ind{brick}s & 2.5 & 0.69 \\
concrete \ind{block}s & 1.5 & 0.42 \\
autoclaved aerated concrete & 3.6 & 1.0 \\
\midrule
\ind{plastic}s -- general & 90 & 25 \\
\ind{PVC} & 80 & 22 \\
synthetic \ind{rubber} & 110 & 30 \\
acrylic \ind{paint} & 61.5 & 17 \\
\midrule
\ind{glass} & 12.7 & 3.5 \\
\ind{fibreglass} (\ind{glasswool}) & 28 & 7.8 \\
\ind{aluminium} & 170 & 47 \\
\ind{copper} & 100 & 28 \\
\ind{galvanised steel}\index{steel}
& 38 & 10.6 \\
\ind{stainless steel} & 51.5 & 14.3 \\
% zinc 61.9 MJ/kg
\bottomrule
\end{tabular}
\end{center}
}{
\caption[a]{Embodied
energy of\index{embodied energy!building materials}\index{embodied energy!wood}\index{embodied energy!rock}\index{embodied energy!glass}\index{embodied energy!metal}
building materials (assuming virgin rather than recycled product is used).
(Dimension stone is natural stone or rock that has been selected and trimmed
to specific sizes or shapes.)
Sources: \tinyurl{3kmcks}{http://www.yourhome.gov.au/technical/index.html},
\cite{Lawson1996}.
\vspace{1in}
}\label{tabEmbMat}
%\marginpar{
\begin{center}
\begin{tabular}{@{}c@{}}
\lowres{\epsfxsize=53mm\epsfbox{../../images/FlatIronHampsteadS.jpg.eps}}%
{\epsfxsize=53mm\epsfbox{../../images/FlatIronHampstead.eps}} \\
\end{tabular}
\end{center}\label{Claire22}
%\caption[a]{ }
%}
}
\end{table}
\begin{table}
\figuremargin{
\begin{tabular}{lr}\toprule
\multicolumn{2}{r}{Embodied energy }\\
\multicolumn{2}{r}{(kWh/m$^2$)} \\
\midrule
Walls \\
\ \ \ timber frame, timber weatherboard, plasterboard lining & 52\\
\ \ \ timber frame, clay brick veneer, plasterboard lining & 156\\
\ \ \ timber frame, aluminium weatherboard, plasterboard lining & 112\\
\ \ \ steel frame, clay brick veneer, plasterboard lining & 168\\
\ \ \ double clay brick, plasterboard lined & \Red{252}\\
\ \ \ cement stabilised rammed earth & 104\\
\midrule
Floors \\
\ \ \ elevated timber floor & \Mahogany{81}\\
\ \ \ 110 mm concrete slab on ground & 179\\
\ \ \ 200 mm precast concrete T beam/infill & 179 \\
\midrule
Roofs \\
\ \ \ timber frame, concrete tile, plasterboard ceiling & 70\\
\ \ \ timber frame, terracotta tile, plasterboard ceiling & \Blue{75}\\
\ \ \ timber frame, steel sheet, plasterboard ceiling & 92\\
\bottomrule
\end{tabular}
}{
\caption[a]{
Embodied energy in various walls, floors, and roofs.\index{embodied energy!building}
Sources:
% \tinyurlb{3kmcks}{http://www.yourhome.gov.au/technical/index.html},
[3kmcks],
\cite{Lawson1996}.
}\label{tabEmbMat2}
}
\end{table}
\Tabref{tab.MyHoCost} uses these numbers to estimate the process energy
for making a three-bedroom house.
%
The {\dem{gross energy requirement}\/}
widens the boundary, including the embodied energy of
urban infrastructure, for example,
the embodied energy of the machinery that makes the raw materials.
A rough rule of thumb to get the gross energy requirement of a building
is to double the process energy requirement \tinyurlb{3kmcks}{http://www.yourhome.gov.au/technical/index.html}.
% *** cite someone?
% my house
%Example: a three-bedroom house, process energy.
% requirement.
\begin{table}
\figuremargin{
\begin{tabular}{lrclcr} \toprule
& Area &$\times$& energy density && energy \\
& (m$^2$)& & (kWh/m$^2$) && (kWh) \\
\midrule
Floors & $100$& $\times$&\Mahogany{$81$}& =& 8100 \\
Roof & $75 $& $\times$& \Blue{75} &=& 5600 \\
External walls &$75$& $\times$& \Red{252}& =& 19\,000 \\
Internal walls &$75$& $\times$& \Red{125}& =& 9400 \\
\midrule
Total & & && & 42\,000 \\
\bottomrule
\end{tabular}
}{
\caption[a]{ Process energy
for making a three-bedroom house.
}\label{tab.MyHoCost}
}
\end{table}
If we share 42\,000\,kWh over 100 years, and double it to estimate
the gross energy cost, the total embodied energy of a house comes to about
2.3\,kWh/d.\label{houseCostEst}
This is the energy cost of the {\em{shell}\/} of the house only --
the bricks, tiles, roof beams.
%"The current figure for total embodied energy CO2 for clay bricks
%(excluding flettons) is 202 kg CO2/ tonne (includes transport to site).
%This equates to 28kgs of CO2 per m? of bricks in a square metre of 102mm
%wide brickwork (60 bricks)."
%
%URL is http://www.brick.org.uk/about-us/why-use-brick.html
% UK year 2000 non-energy mineral production is 307 M t/y.
% heavy clay industry consumes about 5.4TWh/y - that is 0.25 kWh per day per person
% UK manufacturing industry: 409 TWh/y - 18.7 kWh/d/p
% chemicals: 89.5 TWh - 4 kWh/d/p
% iron and steel 56
% metal 52.3 (presumably other metals)
% food and beverage industry 47.4
%% see _stuff.tex
%\section{Industry} % this just contains a bunch of photos
%\input{industry.tex} now nothing.
\small
\section{Notes and further reading}
\beforenotelist
\begin{notelist}
\item[page no.]
\item[\npageref{pDefraCarbonSEI}]
{\nqs{ A subsequent more-detailed study commissioned by DEFRA
estimated that the embodied carbon
in imports is about 6.2 tons \COOe\ per person.
}}
\cite{DefraCarbonSEI}.
\item[Further resources:]
\myurlb{www.greenbooklive.com}{http://www.greenbooklive.com/}
has life cycle assessments of building products.
Some helpful cautions about life-cycle
analysis:
\myurlb{www.gdrc.org/uem/lca/life-cycle.html}{http://www.gdrc.org/uem/lca/life-cycle.html}.
More links:
\myurlb{www.epa.gov/ord/NRMRL/lcaccess/resources.htm}{http://www.epa.gov/ord/NRMRL/lcaccess/resources.htm}.
\marginfig{
\begin{center}
\epsfxsize=53mm\lowres{\epsfbox{../../images/ConcreteSteelBridgeS.eps}}%
{\epsfbox{../../images/ConcreteSteelBridge.eps}}
\end{center}
%}{
\caption[a]{
Millau Viaduct in France, the highest bridge in the world.
Steel and concrete, 2.5\,km long and 353\,m high.
}
%\end{figure}
}
\end{notelist}
\normalsize
}% end troublesoem page hack
%\chapter{Freight}
%\label{ch.freight}
%\input{freight.tex}
%\chapter{Transport technology II}
%\input{transport2.tex}
%\bset\chapter{\bcol{Storage II}}
%\input{storage2.tex}
\dvipsb{technical chapters}%% end of technical chapters
\cleardoublepage
% \addtocontents{toc}{\protect\addvspace{10pt}}
\chtweak\chtweak\chtweak
\bset\part{\bcol{Useful data}}
\bset\chapter{\bcol{Quick reference}}
\section{SI Units}
\begin{quotation}
{\bf{The watt}}.\index{watt}
This SI unit is named after James Watt.\index{Watt, James}
As for all SI units whose names are derived from the\index{nomenclature}
proper name of a person, the first letter of its symbol is\index{capitalization}
uppercase (W). But when an SI unit is spelled out, it should\index{spelling}
always be written in lowercase (\ind{watt}),
with the exception of the ``degree \ind{Celsius}."
\par
\hfill
from wikipedia
\end{quotation}
\noindent
\ind{SI} stands for Syst\`eme International.
SI units are the ones that all engineers should use,
to avoid losing spacecraft.
\begin{table}[h]
\figuredangle{
\begin{tabular}{cc}
\begin{tabular}{lll} \toprule
\multicolumn{3}{c}{ \SI\ units
}\\ \midrule
energy & one \ind{joule} & 1\,J \\
power & one \ind{watt} & 1\,W \\
force & one \ind{newton} & 1\,N \\% = 1\,J/m \\
length & one \ind{metre} & 1\,m \\
time & one \ind{second} & 1\,s \\
temperature & one kelvin & 1\,K \\
%temperature & one degree Celsius & 1\degreeC \\
\bottomrule
\end{tabular}&
\begin{tabular}{*{10}{c}} \toprule
%% SI-Prefixes
prefix
%& yotta & zetta
& kilo
& mega
& giga
& tera
& peta
& exa
%& %hecto
\\ \midrule
symbol
% & Y & Z
&k&M&G&T&P&E
% E & P & T & G & M & k %& %h &
\\
factor
% & $10^{24}$ & $10^{21}$
& $10^{3}$
& $10^{6}$
& $10^{9}$
& $10^{12}$
& $10^{15}$
& $10^{18}$
%& $10^{2}$ \\ \bottomrule
\\ \bottomrule
\\ \toprule
prefix & centi & milli & micro & nano & pico & femto \\% & atto \\
%& zepto & yocto \\
\midrule
symbol & c & m & $\mu$ & n & p & f \\%& a \\
% & z & y\\
factor & $10^{-2}$ & $10^{-3}$ & $10^{-6}$ & $10^{-9}$ & $10^{-12}$ & $10^{-15}$ %% & $10^{-18}$
% & $10^{-21}$ & $10^{-24 }$
\\ \bottomrule
\end{tabular}
\end{tabular}
}{
\caption[a]{SI units and prefixes}
}
\end{table}
\beginfullpagewidth
\section{My preferred units for energy, power, and transport efficiencies}
\begin{oldcenter}
\begin{tabular}{llll} \toprule
\multicolumn{3}{c}{ My preferred units, expressed in SI
}\\ \midrule
energy & one kilowatt-hour & 1\,kWh & 3\,600\,000\,J \\
power & one kilowatt-hour per day & 1\,kWh/d & (1000/24)\,W $\simeq$ 40\,W \\
force & one kilowatt-hour per 100\,km & 1\,kWh/100\,km & 36\,N \\
time & one hour & 1\,h & $3600$\,s \\
& one day & 1\,d & $24 \times 3600$\,s $\simeq 10^5$\,s \\
& one year & 1\,y & $365.25 \times 24 \times 3600$\,s $\simeq \pi\times10^7$\,s \\
% mass & one ton & 1\,t & 1000\,kg \\
force per mass & kilowatt-hour per ton-kilometre & 1\,kWh/\tkm & 3.6\,m/s$^2$ ($\simeq 0.37g$) \\
\bottomrule
\end{tabular}
\end{oldcenter}
\section{Additional units and symbols}
% In this book I use the following additional \ind{units}:
\begin{oldcenter}
\begin{tabular}{llll} \toprule
Thing measured & \index{units}unit name & symbol & value \\ \midrule
humans & person & p &\\
mass & ton & t & $1\,{\rm{t}} = 1000\,\kg$ \\
&gigaton &Gt & $1\,{\rm{Gt}} = 10^9 \times 1000\,\kg = 1\,{\rm{Pg}}$\index{Pg}\index{petagram} \\
transport & person-kilometre & p-km \\
transport & \tonne-kilometre & t-km \\
volume & litre & l & 1\,l $ = 0.001\,\m^3$ \\
area & square kilometre & sq km, km$^2$ & 1\,sq km $ = 10^6\,\m^2$ \\
& hectare & ha & 1\,ha $ = 10^4\,\m^2$ \\
& Wales & & 1\,Wales $ = 21\,000\,\km^2$ \\
& London (Greater London) & & 1\,London $ = 1580\,\km^2$ \\
% http://en.wikipedia.org/wiki/Greater_London
% & London (up to M25) & & 1\,M25 $ = 2300\,\km^2$ \\
energy & \ind{Dinorwig} & & 1\,Dinorwig = 9\,GWh \\
\bottomrule
\end{tabular}
\end{oldcenter}
\ENDfullpagewidth
% CUTTABLE
% For example, a bus that travels 10\,km with 20 people on board has
% delivered an amount of personal transportation equal to
% 200\,p-km.
% A truck that shifts 10\,tons of stuff a distance of 100\,km
% provides 1000\,t-km of transport.
% END CUTTABLE
% Energy costs
% When I write 1\,km$^2$ I mean 1\,(km)$^2$, not 1000\,m$^2$.
\section{Billions, millions, and other people's prefixes}
Throughout this book ``a billion'' (1\,bn) means a standard
American billion, that is, $10^9$, or a thousand million.
A trillion is $10^{12}$.
The standard prefix meaning ``billion'' ($10^9$) is ``giga.''
% In
% Don't confuse
% Giga, trillion, and billion.
% A billion is a giga- ($10^9$).
In \ind{continental Europe}\index{Europe!continental},
the abbreviations \ind{Mio} and \ind{Mrd}
denote a \ind{million} and \ind{billion} respectively.
Mrd is short for \ind{milliard},
which means $10^9$.
The abbreviation \ind{m} is often used to mean million, but this abbreviation is
incompatible with the SI -- think of mg (milligram) for example.
So I don't use m to mean million. Where some people use m,
I replace it by M\@. For example, I use \ind{Mtoe}\index{toe} for million \tonnes\ of oil equivalent,
and \ind{Mt}\,\COO\ for million \tonnes\ of \COO\@.
% The abbreviation \ind{bn} is often used to mean billion.
% I prefer \ind{b}.
% But perhaps I should stick to \ind{bn}.
\section{Annoying units}
There's a whole bunch of commonly used units that are annoying
for various reasons. I've figured out what some of them mean.
I list them here, to help you translate the media stories you read.
% \beforeqa
\qa{Homes}{
\noindent
The ``\ind{home}''\label{pHOME}
is commonly used when
describing the power of renewable facilities.
%the one of the most common units used to describe the power of a new
%\windfarm.
For example,
%% http://news.bbc.co.uk/1/hi/scotland/glasgow_and_west/6031995.stm
``The \pounds300\,million
Whitelee \windfarm's 140 turbines will generate
322\,MW -- enough to power 200\,000 homes.''
%I think that a `home' is about 0.6\,kW, or 14\,kWh per day.
%This guess is consistent with the above quote, assuming that
%the turbines will actually generate about 35\% of 322\,MW.
%% http://www.eon-uk.com/images/Buildingasustainablefuture.pdf
The ``home'' is defined by
%E-ON and
the British Wind Energy Association to be a power of
%4700\,kWh/y, or 13\,kWh/d.
% However, says a home is
\Red{4700\,kWh per year}
% household
[\myurlb{www.bwea.com/ukwed/operational.asp}{http://www.bwea.com/ukwed/operational.asp}].
That's 0.54\,kW, or \Red{13\,kWh per day}.
%% 12.87\,kWh/d
%% they assume 860g CO2/kWh for coal displacement.
(A few other organizations use 4000\,kWh/y per household.)
% That means one ``home'' uses 0.46\,kW or \Red{11\,kWh/d}.)
The ``home'' annoys me because I worry that people
confuse it with {\em the total power consumption of
% 2.5 people,
the occupants of a home} -- but the latter is actually about
% 125 * 2.5 / 13 = 24
24 times bigger.
The ``home'' covers the average domestic {\em{electricity}\/}
consumption of a household, only.
Not the household's home heating. Nor their workplace. Nor their transport.
Nor all the energy-consuming things that society does for them.
% If I announced a new renewable source that would
%provide enough power for ``all the homes in Britain,''
%I bet people would think that all Britain's power was covered.
%But using the standard exchange rates, the amount of power would be
%just 14\,GW, which is only one third of current electricity consumption,
%and only one twentieth of the total power consumption of the UK.
% CUTTABLE ***
Incidentally, when they talk of the \COO\ emissions of a ``home,''
the official exchange rate appears to be 4 \tonnes\ \COO\ per home per year.
% and 770\,g\,\COO\ per kWh.
% CHECK?
}
% 1TWh/y - enough to power more than 200,000 homes
%% http://news.bbc.co.uk/1/hi/sci/tech/4620350.stm
%% CUTTABLE ***
\qa{Power stations}{
\noindent
Energy saving ideas are sometimes described
in terms of \ind{power station}s.
For example according to a BBC report on putting
new everlasting LED lightbulbs in traffic lights,
``The power savings would be huge --
keeping the UK's traffic lights running requires the equivalent of
two medium-sized power stations.''
\myurlb{news.bbc.co.uk/1/low/sci/tech/specials/sheffield_99/449368.stm}{http://news.bbc.co.uk/1/low/sci/tech/specials/sheffield_99/449368.stm}
% `Replacing 50 per cent of the lighting in the UK with
% Gallium Nitride light-emitting diodes
% would save the energy produced by
% five medium-sized power stations' (Cambridge University press release,
% 2 June 2003).
\marginfig{
\noindent%
\mbox{\epsfxsize=50mm\epsfbox{../data/coalC.eps}} \\[-2.5mm]
\begin{center}
{\small{\sf Power (MW)}}\\
\end{center}
\caption[a]{
Powers\index{power station!coal}\index{Drax}\index{Eggborough}
of Britain's coal power stations.\index{coal power station}
%% of this 30GW, 20.6GW is ``opted in'' as of 2007. 8.7 is opted out.
I've highlighted in blue 8\,GW of generating capacity that will close by 2015.
% 3.4\,GW of nuclear power will also close by 2015, and
% source http://www.publications.parliament.uk/pa/cm200506/cmselect/cmenvaud/584/584we48.htm
% date 21 sept 2005
% another 5.8\,GW by 2019.
2500\,MW, shared across Britain,
is the same as 1\,kWh per day per person.
} \label{fig.coalC}
}
What is a medium-sized power station? 10\,MW? 50\,MW? 100\,MW? 500\,MW?
I don't have a clue. A google search indicates that
some people think it's 30\,MW, some 250\,MW, some
500\,MW (the most common choice),
and some 800\,MW\@. What a useless unit!
%% http://www.cabinetoffice.gov.uk/strategy/downloads/work_areas/energy/submissions/OxfordTrust.pdf
%% http://archive.nics.gov.uk/eti/000623c-eti.htm
%% http://www.iop.org/EJ/article/1402-4896/1999/T80B/038/physscr9_T80B_038.pdf
%% http://nucnews.net/nucnews/2002nn/0203nn/020312nn.htm
%% http://forum.cygnus-study.com/archive/index.php/t-534.html
%% http://www.iop.org/Jet/fulltext/JETR99013.pdf
%% ``1 million tonnes of C02 emissions within one year. This is equivalent to the pollution belched out by one medium-sized power station.''
%% http://www.prnewswire.co.uk/cgi/news/release?id=185285 (which means 200MW)
% I feel that there might be a case for making `a big power station'
% a standard power unit -- equal to one gigawatt, say. Many nuclear power
% stations put out one gigawatt. But I think
% `Medium power stations' are an
% especially useless unit, since
% Nobody knows
% how many medium power stations our country's power consumption
% corresponds to.
Surely it would be clearer for the article
about traffic lights to express what it's saying as a percentage?
``Keeping the UK's traffic lights running requires 11\,MW of electricity,
which is 0.03\% of the UK's electricity.''
This would reveal how ``huge'' the power savings are.
% The only problem with expressing traffic lights in such precise terms
% instead of hiding them behind the fuzzy veil of ``medium-sized power stations''
% is that the resulting statement would not sound like
% ``huge'' power savings any more!
%% data/coalpowerstns
Figure \ref{fig.coalC} shows the powers of the UK's 19 coal power stations.
% \myurl{http://www.ukqaa.org.uk/PowerStation.html}
}
\qa{\ind{Cars taken off the road}
}{
\noindent
Some advertisements describe
reductions in \COO\ pollution
in terms of the ``equivalent number of cars taken off the road.''
For example, Richard Branson says that if Virgin Trains' Voyager fleet
switched to 20\% biodiesel -- incidentally, don't you feel it's outrageous
to call
% Fri 8/6/07
a train a ``green bio\-die\-sel-powered train'' when it runs on 80\% fossil fuels and
just 20\% biodiesel? --
% and that they call a product ``biodiesel'' even though is only 20\% biodiesel?
sorry, I got distracted.
Richard Branson says that {\em{if}\/} Virgin Trains' Voyager fleet
switched to 20\% biodiesel -- I emphasize the ``{\em{if}}'' because people like Beardie
% and BP
are always getting media publicity for announcing that they are {\em{thinking of}\/} doing
good things, but some of these
fanfared initiatives are later quietly cancelled,
such as the idea of towing aircraft around airports to make them greener --
% http://www.virgin.com/News/Articles/VirginAtlantic/2006/04122006.aspx
% http://www.timesonline.co.uk/tol/news/environment/article3516551.ece
sorry, I got distracted again.
Richard Branson says that {\em{if}\/} \ind{Virgin Trains}' Voyager fleet
switched to 20\% biodiesel,
then there would be a reduction of 34\,500 \tonnes\
of \COO\ per year, which is equivalent
to ``23\,000 cars taken off the road.''
% incidentally they say that B20 biodiesel cuts coo by UP TO 14%
This statement reveals the exchange
rate:
\begin{center}
``one car taken off the road'' $\longleftrightarrow$ $-1.5$\,\tonnes\ per year of \COO\@.
\end{center}
}
\qa{Calories
}{
\noindent
The calorie is annoying because the diet community call a \ind{kilocalorie}\index{kcal}
a \ind{Calorie}\index{calorie}.
1 such food Calorie = 1000 calories.% = 4200\,J\@.
$2500\,\kCal = 3\, \kWh = 10\,000\,\kJ = 10\,\MJ.$
}
\qa{Barrels
}{
\noindent
An annoying unit loved by the oil community, along with
the \tonne\ of oil.
% Barrels are annoying because
Why can't they stick to one unit?
A barrel of oil is 6.1\,GJ or 1700\,kWh.
Barrels are doubly annoying because there are multiple definitions
of barrels, all having different volumes.
Here's everything you need to know about barrels of oil.
One barrel is 42 U.S.\ gallons, or
159 litres.
One barrel of oil is
0.1364 \tonnes\ of oil.
One barrel of crude oil has an energy of 5.75\,GJ\@.
One barrel of oil weighs 136\,kg.
One \tonne\ of crude oil is 7.33 barrels
% this is consistent with 0.1364
and 42.1\,GJ\@.
% Sat 15/12/07 alternate view:
% ORNL \tinyurl{2hcgdh}{http://cta.ornl.gov/data/appendix_b.shtml} say
% 1G barrel is 6119 PJ k M G T P
% 1 barrel is 6119 MJ
The carbon-pollution rate of crude oil is
400\,kg of \COO\ per barrel.
\myurlb{www.chemlink.com.au/conversions.htm}{http://www.chemlink.com.au/conversions.htm}
This means that when the price of oil is \$100 per barrel,
oil energy costs 6\cents\ per kWh.
% This means that when the price of oil is \$90 per barrel,
% people are paying \cents5.4 per kWh,
% and they are paying \$225 per ton of \COO\ emitted.
If there were a \ind{carbon tax} of \$250 per ton of \COO\ on fossil fuels,
that tax would increase the price of a \ind{barrel of oil} by \$100.
}
\qa{Gallons
}{
\noindent
The \ind{gallon} would be a fine human-friendly unit, except the Yanks
% Americans
messed it up by defining the gallon differently from
everyone else, as they did the \ind{pint} and the \ind{quart}.
The US\ volumes are all roughly
five-sixths of the correct \ind{volume}s.
1\,US gal = 3.785\,l = 0.83\,imperial gal.
1\,imperial gal = 4.545\,l.
}
\qa{Tons}{
\noindent
Tons\index{ton} are annoying because there are short \tonnes, long \tons\ and metric \tonnes.
They are close enough that I don't bother distinguishing between them.
1 short ton (2000\,lb) = 907\,kg;
% 1 short ton (2000\,lb) = 907.2\,kg; 2.2047 lb per kg
1 long ton (2240\,lb) = 1016\,kg;
1 metric ton (or \ind{tonne}) = 1000\,kg.
}
\qa{\ind{BTU} and \ind{quad}s}{
\noindent
British thermal units are annoying
because they are neither part of the {\em{Syst\`eme Internationale}},
nor are they of a useful size. Like the useless joule, they are too small,
so you have to roll out silly prefixes
like ``quadrillion'' ($10^{15}$) to make practical use of them.
1\,kJ is 0.947\,BTU\@.
1\,kWh is 3409\,BTU\@.
A ``quad'' is 1 quadrillion BTU = 293\,TWh.
% and it is almost exactly 1EJ
% terawatt-hours.
}
\section{Funny units}
\beforeqa
\qa{Cups of tea}{
\noindent
\index{cup of tea}Is this a way to make solar panels sound good?\index{cup of tea}
``Once all the 7\,000 photovoltaic panels
are in place, it is expected that the solar panels will create 180\,000
units of renewable electricity each year -- enough energy
to make {\bf nine million cups of tea}.''
This announcement thus equates 1\,kWh to 50 cups of tea.
As a unit of volume,
1 US \ind{cup} (half a US \ind{pint}) is officially 0.24\,l;\index{litre}\index{volume!units}
but a cup of \ind{tea} or \ind{coffee} is usually about 0.18\,l.
% an imperial cup (half an imperial pint) =
% I confirm that to
To raise
50 cups of water, at 0.18\,l per cup, from
15\degreesC\ to 100\degreesC\ requires 1\,kWh.
So ``nine million cups of tea per year'' is another way of saying ``20\,kW.''
}
\qa{Double-decker buses, Albert Halls and Wembley stadiums}{
\noindent
``If everyone in the UK that could, installed cavity wall insulation,
we could cut carbon dioxide emissions by a huge 7 million
\tonnes. That's enough carbon dioxide to fill nearly 40 million
double-decker buses or fill the new Wembley stadium 900 times!''
% http://www.energysavingtrust.org.uk/resources/useful_statistics
From which we learn the helpful fact that
one \ind{Wembley} is 44\,000 \ind{double decker bus}es.
% The bowl volume of wembley is 1\,139\,100 m^3
% http://www.wembleystadium.com/brilliantfuture/learningResources/
% Wembley Stadium has approximately 180,000sq metres of internal floor space
% Area of roof: Metal Roof = 40,000 m2, Single Ply Roof = 12,000 m2
% Pitch dimension and technology Including run off area:10,096m2
Actually, Wembley's bowl has a volume of 1\,140\,000\,m$^3$.
%\subsubsection{Albert Halls}
%% http://www.greenenergy.uk.com/site/environment/Energy%20Conservation.aspx
%If everyone in the UK installed just one energy saving light bulb, the
%savings in \COO\ emissions would fill London's Royal Albert Hall
%nearly 3,000 times.
``If every household installed just one energy saving light bulb,
% the
% electricity saved in a year could power the Blackpool Illuminations
% for nearly 900 years and
there would be enough carbon dioxide saved
to fill the \ind{Royal Albert Hall} 1,980 times!''\index{Albert Hall}
(An Albert Hall is 100\,000\,m$^3$.)
% As I pointed out on \pref{photairvolume},
Expressing amounts of \COO\ by volume
rather than mass is a great way to make them sound big.
Should ``1\,kg of \COO\ per day'' sound too small,
just say ``200\,000 litres of \COO\ per year''!
\margintab{
\begin{tabular}{r@{\ $\leftrightarrow$\ }c}\toprule
% \multicolumn{2}{c}{\sc{ }} \\
mass of \COO & volume \\ \midrule
2\,kg \COO & 1\,m$^3$ \\
1\,kg \COO & 500\,litres \\
44\,g \COO & 22\,litres \\
2\,g \COO & 1\,litre \\
\bottomrule
\end{tabular}
\caption[a]{
Volume-to-mass conversion.
% every 44\,g of \COO\ occupies 22\,litres.
}
}
}
%\section{Volumes and areas}
\section{More volumes}
% 1 US gallon = 3.785 litres. 1 imperial \ind{gallon} = 4.546 litres.
A \ind{container} is 2.4\,m wide by 2.6\,m high by (6.1 or 12.2) metres long
\marginfig{
\begin{center}
\begin{tabular}{@{}c@{}}
{\mbox{\epsfxsize=53mm\epsfbox{../../images/TEU.eps}}}
\\
\end{tabular}
\end{center}
\caption[a]{A twenty-foot container \par
(1 TEU).
}\label{TEU}
}%
(for the \ind{TEU} and \ind{FEU} respectively).
% Can take 24\,000\,kg.
% exterior vol seems to be 38mmm
One \ind{TEU}\index{volume} is the size of a small 20-foot
\ind{container} -- an interior volume of about 33\,m$^3$. Most
containers you see today are 40-foot
containers with a size of 2\,TEU\@.
A 40-foot container weighs 4\,tons and can carry
26\,tons of stuff; its volume is 67.5\,m$^3$.
% Container ship freight is roughly 2.4 billion kg per y.
% Prices start at \$500 per container, which works out
% to \$0.02 per kg.
A \ind{swimming pool} has a volume of about 3000\,m$^3$.
% 50 25 2.5 is 3125
% An Albert Hall has a volume of roughly 100\,000 cubic metres.
% one \ind{Wembley} is 44\,000 \ind{double decker bus}es.
One \ind{double decker bus} has a volume of 100\,m$^3$.
One hot air \ind{balloon}\index{hot air balloon} is 2500\,m$^3$.
% BP say 1 hot air balloon = 4 tonnes of CO2
The great \ind{pyramid} at \ind{Giza}\index{great pyramid}
has a volume of
2\,500\,000 cubic metres.
\section{Areas}
The \ind{area} of the earth's surface\index{earth!area} is
\margintab{
\begin{tabular}{cl} \toprule
hectare &$= 10^4\, \m^2$ \\%&$= 10^{-2}\, \km^2$\\
acre &$= 4050\, \m^2$ \\%&$= 0.004\, \km^2$\\
square mile % &$= 2.6\times 10^{6}\, \m^2$
&$= 2.6\, \km^2$\\
square foot &$= 0.093\,\m^2$ \\%&$= 9.3\times 10^{-8}\, \km^2$\\
square yard &$= 0.84\,\m^2$ \\%&$= 8.4\times 10^{-7}\, \km^2$\\
\bottomrule
\end{tabular}
% }{
\caption[a]{Areas.
% The population density of England is
% 380 people per km$^2$, or 2630\,m$^2$ per person.
}
\label{tab.area}
}% }\end{table}
$500\times 10^{6}\,\km^2$;
the land area is
$150\times 10^{6}\,\km^2$.
A typical soccer field has an area of 8000\,m$^2$.
An American Football field has an area of 5350\,m$^2$.
% In the UEFA Champions League a football field must be exactly 105x68m, which is an area of 7,140 m². An American Football field, including both end zones, is 360 ft by 160 ft, or 57,600 square-feet (5,351.2 m²).
My typical British 3-bedroom house has a floor area of 88\,m$^2$.
In the USA,
% in the last 25 years, the average size of a single-family house
% has increased from 1740 square feet (162\,m$^2$) to 2330 square feet (216\,m$^2$).
the average size of a single-family house
is 2330 square feet (216\,m$^2$).
%we should include a {\dem\ind{sunniness factor}\/}
% of $1/3$}}.%
\begin{table}[btp]
\figuremargin{
\begin{center}
\begin{tabular}{lrl} \toprule
Land use & area per person & percentage \\
& \multicolumn{1}{r}{(m$^2$)} & \\
\midrule
-- domestic buildings & 30\phantom{.6} & \phantom{8}1.1 \\
-- domestic gardens & 114\phantom{.6} & \phantom{8}4.3 \\
-- other buildings & 18\phantom{.6} & \phantom{8}0.66 \\
-- roads & 60\phantom{.6} & \phantom{8}2.2 \\
-- railways & 3.6 & \phantom{8}0.13 \\
-- paths & 2.9 & \phantom{8}0.11 \\
-- greenspace & 2335\phantom{.6} & 87.5 \\
-- water & 69\phantom{.6} & \phantom{8}2.6 \\
-- other land uses & 37\phantom{.6} & \phantom{8}1.4 \\
\midrule
Total & 2670\phantom{.6} & 100 \\
\bottomrule
%% cf agricultural area per person in the UK is 2800
%% IDEA - remove the percentages, add link to that figure.
\end{tabular}
\end{center}
}{
\caption[a]{Land areas, in England, devoted to different uses.
Source:
Generalized Land Use Database Statistics for England 2005.
\protect\tinyurl{3b7zdf}{http://www.communities.gov.uk/publications/planningandbuilding/generalizedlanduse}
}
\label{tabLandAreas}% referred to in notes of solarnotes.tex
}
\end{table}
%\section{Numbers}
\section{Powers}
If we add the suffix ``e'' to a power,
this means that we're explicitly talking about electrical power.
So, for example, a power station's output might be 1\,\GWe, while
it uses chemical power at a rate of 2.5\,\GW\@.
Similarly the suffix ``th''\index{th} may be added to indicate that
a quantity of energy is thermal energy.
The same suffixes can be added to amounts of energy.
``My house uses 2\,\kWhe\ of electricity
per day.''\index{GW(e)}\index{MW(e)}\index{e}\index{kW(e)}\index{W(e)}
If we add a suffix ``p'' to a power, this indicates that it's a
``peak'' power, or capacity. For example, 10\,m$^2$ of panels might have
a power of 1\,kWp.\index{p}\index{kWp}\index{MWp}\index{GWp}\index{Wp}
% ton of coal equivalent = 29.3 GJ. = 8000 units
% 1Megaton = 4.2e15 J. = 10$^9$ UNITS (actually 1.17e9)
\begin{boxfloat}
\figuremargin{
\begin{framedalgorithm}
\begin{center}
\begin{tabular}{rclcl}
1000 BTU per hour &=& 0.3\,kW &=& 7\,kWh/d \\ % \,hr \\
1 horse power (1\,\ind{hp} or
1\,\ind{cv} or 1\,\ind{ps}) &=& 0.75\,kW &=& 18\,kWh/d \\
& & 1\,kW &=& 24\,kWh/d \\
\end{tabular}
\end{center}
\medskip
\begin{tabular}{l@{$\:=\:$}r@{\,kWh}}
1\,therm & 29.31 \\
1000\,BTU & 0.2931 \\ % $\times 10^{-3}$ \\
1\,MJ & 0.2778 \\
1\,GJ & 277.8 \\
1\,toe (\index{toe}ton of oil equivalent) & 11\,630 \\%% Mtoe
1\,kcal & 1.163$\times 10^{-3}$ \\
\end{tabular}
\medskip
\begin{tabular}{ccccccc}
1\,kWh &=& 0.03412 & 3412 & 3.6 & 86$\times 10^{-6}$ & 859.7\\
& & therms & BTU & MJ & toe & kcal\\
\end{tabular}
% ton of oil equivalent = 41.8GJ = 10 {\tonne}s of TNT. = 12\,000\,kWh
\end{framedalgorithm}
}{
\caption[a]{How other energy and power units relate to the kilowatt-hour
and the kilowatt-hour per day.}
\label{box.unit}
}
\end{boxfloat}
1\,kWh/d = $\frac{1}{24}\,\kW$.
% 1\,TWh/y
1\,toe/y = 1.33\,kW\@.
Petrol comes out of a \ind{petrol pump} at about half a litre per second.
So that's 5\,kWh per second, or 18\,MW\@.
% checked Fri 18/4/08.
The power of a \ind{Formula One} racing car is 560\,kW\@.
% \subsection{Useful numbers}
UK electricity consumption is 17\,kWh per day per person, or 42.5\,GW per UK.
% \subsection{Air-conditioning}
``One ton'' of air-conditioning = 3.5\,kW\@.
%1 ton of cooling is equivalent to 12,000 BTU/h or 3.517kW.
% This is approximately the power required to melt one ton of ice in 24 hours.
%
%12,000 Btu/h
% According to three dudes on the internet,
% It's the heat removal-rate needed to freeze one ton of ice per day,
% and a standard one ton A/C unit consumes 1.335\,\kWe,
% and cools an area of 400 square feet (37\,m$^2$) in a typical US building.
% The latent heat of fusion for ice is 144 BTU/lb. For one ton, that is 2000 lb x 144 BTU/lb, or 288,000 BTU. Refrigeration's roots are in the ice making industry, and the ice guys wanted to convert this into ice production. If 288,000 BTU are required to make one ton of ice, divide this by 24 hours to get 12,000 BTU/Hr required to make one ton of ice in one day.
% One BTU is the heat removal required to lower the temperature of one pound of water by one degree F.
% latent heat of fusion of ice is 333.55 J/g
% \section{More numbers}
\subsection{World power consumption}
World power consumption is 15\,TW\@.
World electricity consumption is 2\,TW\@.
\subsection{Useful conversion factors}
To change TWh per year to GW, divide by 9.
%% 8.766
\noindent
1\,kWh/d per person is the same as 2.5\,GW per UK, or 22\,TWh/y
\rlap{\hbox{per UK}}\@.
\noindent
To change mpg (miles per UK gallon) to km per litre, divide by 3.
% US edition
% To change mpg (miles per imperial gallon) to km per litre, divide by 2.35.
\noindent
%\begin{tabular}{c@{\ $=$\ }c}\toprule
%\multicolumn{2}{c}{\sc{Useful identities}}\\ \toprule
At room temperature, ${1\,kT} = \frac{1}{40}{\rm{eV}}$.
\noindent
% Visible photon & 2\,eV \\
At room temperature, ${1\,kT}$ per molecule = {2.5\,kJ}/mol.
\subsection{Meter reading}
How to convert your gas-meter reading\index{gas meter}\index{meter reading}
into kilowatt-hours:\index{unit conversion}\index{cubic foot}\index{cubic metre}
% * units used (cubic ft)
% * x 2.83 (for metric conversion - omit if your meter measures cubic metres)
% * x 1.02264 [vol conversion factor]
% * x 40.2 [calorific value]
% * ÷ 3.6 -> kWh
\begin{itemize}
\item
If the meter reads {\bf{100s of cubic feet}},
take the number of units used, and multiply by {\bf{32.32}}
to get the number of kWh.
\item
If the meter reads {\bf{cubic metres}},
take the number of units used, and multiply by {\bf{11.42}}
to get the number of kWh.
\end{itemize}
%% 100 (ft ** 3) = 2.83168466 m ** 3
\section{Calorific values of fuels}
Crude oil: 37\,MJ/l; 10.3\,kWh/l.
%\section{Energy intensity of transport modes in the USA}
\margintab{\small
\begin{tabular}{lr}\toprule
\multicolumn{2}{r}{kWh/t-km} \\ \midrule
inland water & 0.083 \\
rail & 0.083\\
truck & 0.75\\
air & 2.8\\
oil pipeline & 0.056\\
gas pipeline & 0.47\\
%int. air & 2.8\\
int'l water container& 0.056\\
int'l water bulk & 0.056\\
int'l water tanker & 0.028\\ \bottomrule
\end{tabular}
\caption[a]{
Energy intensity of transport modes in the USA\@.
Source: \cite{WeberMatthews}.
}\label{tabUStransp}
}
\noindent
Natural gas: 38\,MJ/m$^3$.
% methane
(Methane has a density of 1.819\,kg/m$^3$.)
\noindent
1 ton of coal: 29.3\,GJ; 8000\,kWh.
% Coal LHV/HHV = 0.96.
% source IPCC page 157
% Hydrocarbons: 30\,000\,\kJ\ per \kg
\noindent
Fusion energy of
ordinary water: 1800\,kWh per litre.
% D$_2$O:
% is 117\,MJ per 18g
% 1\,kWh\ $\leftrightarrow$ 250\,g of \COO\ (oil, petrol)
% for gas, 1\,kWh\ $\leftrightarrow$ 200\,g \COO.
% 1kWh(e) = 0.445 kg CO2 from Gas
% 1kWh = 0.955 kg CO2 from Coal
% (from Carbon trust talk)
% Petrol:
% 1\,kWh\ $\leftrightarrow$ 250\,g of \COO\ (oil, petrol).
% 1 litre of fuel $\leftrightarrow$ 10\,kWh $\leftrightarrow$ 2.2\,kg of \COO. (check)
\noindent
See also \tabref{pFuels}, \pref{pFuels},
and \tabref{pWoodTable}, \pref{pWoodTable}.
\section{Heat capacities}
The heat capacity of air is
% 1000\,J/kg/\ndegreeC\@.
1\,kJ/kg/\ndegreeC,
or
29\,J/mol/\ndegreeC\@.
The density of air is 1.2\,kg/m$^3$.
%% at 20 C, it's 1.2; at 0 degrees, 1.29.
So the heat capacity of air per unit volume
is
%1\,kJ/kg/\ndegreeC\ $\times$ 1.2\,kg/m$^3 =
1.2\,kJ/m$^3$/\ndegreeC\@.
Latent heat of vaporization of water: 2257.92\,kJ/kg.
% Specific enthalpy of steam (at atmospheric pressure): 2675.43\,kJ/kg.
Water vapour's heat capacity: 1.87\,kJ/kg/\ndegreeC\@.
% 2.0267\,kJ/kg/\ndegreeC\@.
Water's heat capacity is 4.2\,kJ/l/\ndegreeC\@.
% \ndegreeC\@.
Latent heat of fusion of ice: 333.55\,kJ/kg.
% which is also 92.65 Wh per kg. Lead-acid is up to 50 Wh/kg.
% relative to water heat capacity, it's the same as 80 degrees.
Steam's density is 0.590\,kg/m$^3$.
\nocite{TreloarLoveCrawford}
% \subsection{Carbon intensity of electricity production}
% In the UK, latest figure for 2007: 505 \tonnes\ \COO\ per GWh.
% Depends on the country!
% Source: PriceWaterHouse, EDF, www.manicore.com 2001
% thanks to http://www.zerocarbonnow.org/
%\begin{table}
% \figuremargin{
%\subsection{Greenhouse-gas intensities of transport in the USA}
\section{Pressure}
Atmospheric pressure:
1\,bar $\simeq$ $10^{5}$\,Pa (pascal).
Pressure under 1000\,m of water: 100\,bar.
Pressure under 3000\,m of water: 300\,bar.
% from itp
% ~/bin/logscale.p > picture.tex
% ~/bin/logscale.p pic=2 N=1 Y=13 extend=1 > ignorance/line.tex
% for here
% 2.5 GW per UK is the same as 1kWh/d per person
% and 21.9145319 TWh / year
% cd ~/sustainable/book/tex
% ~/bin/logscale2.p N=2.7 rescale=0.91 metres="kWh/d each" inches="GW / UK" feet="TWh/y / UK" N=3 scale1=1 scale2=0.4 scale3=0.0456318 o3=3 > upicture.tex
%% was wrong:
% scale1=1 scale2=2.5 scale3=21.9145319 o3=-1 > upicture.tex
% gasoline = \$3 per gallon to consumer in USA. Which is \$0.79 per litre.
% Plan:
% Make one diagram with energy units only.
% Add toe to it.
% Then make a second diagram showing kWh/d each (heat)
% and kWh/d (electricity), alongside all the Carbon scales
% including GtC/y/World?
%
% One {\tonne} of oil per person year is 32 kWh/day per person.
% One {\tonne} of oil per UK per year is 32/60e6 kWh/day per person.
% so scale=32 for toe/d
% scale=32.0/60.0 for Mtoe/y
% ~/bin/logscale2.p N=2.7 rescale=0.91 metres="kWh/d each" unit2="GW / UK" unit3="TWh/y / UK" unit4="Mtoe/y / UK" scale4=0.533333 stripes=4 N=3 scale1=1 scale2=0.4 scale3=0.0456318 o3=3 > upicture.tex
% latex2eps.sh tmp < upicture.tex ; gv tmp.eps
% ~/bin/logscale2.p N=2.7 rescale=0.91 metres="kWh/d each" N=3 scale1=1 o3=3 > upicture2.tex
% latex2eps.sh tmp2 < upicture2.tex ; gv tmp2.eps
% Heavy fuel oil -- carbon emissions:
% $8.25\times 10^{-1}$\,MtC/Mtoe.
% $0.825$\,MtC/Mtoe.
\section{Money}
I assumed the following exchange rates
when discussing money:
\euro 1 = \$1.26; %% euro in dollars Mon 19/6/06
\pound 1 = \$1.85 ; %% pound in dollars Mon 19/6/06
\$1 = \$1.12 Canadian.
These exchange rates were correct in mid-2006.
%\euro= 1.26 ; %% euro in dollars Mon 19/6/06
%\pound = 1.85 ; %% pound in dollars Mon 19/6/06
%\$1 = 1.12 Canadian dollars ; %% dollar in canadian dollars
% euro / pound = 1.26/1.85 = 0.68108
% pound/euro = 1.4683
% UK average income \$34,000. (2004)
%\vfillone
%\clearpage
%\pagebreak[4]
\section{Greenhouse gas conversion factors}
%\margintab{
\begin{myfloat}[h]
\twofigures{80mm}{80mm}{
\begin{tabular}{cc}
\begin{tabular}[b]{lr}\toprule
France &83\\
Sweden &87 \\
Canada &220 \\
Austria &250 \\
Belgium &335 \\
European Union& 353 \\
Finland &399 \\
Spain &408 \\
Japan &483 \\
Portugal& 525\\
United Kingdom &580 \\
Luxembourg & 590 \\
Germany &601 \\
USA &613 \\
Netherlands& 652 \\
Italy &667 \\
Ireland &784 \\
Greece &864 \\
Denmark &881\\
\bottomrule
\end{tabular}
\end{tabular}
}{
\caption[a]{{Carbon intensity\index{data!carbon intensity of electricity production}
of electricity production}\index{emissions!of electricity production}
(g\,\COO\ per kWh of electricity).}
}{
\begin{tabular}{lr}
\toprule
Fuel type & emissions \\
& (g\,\COO\ per kWh\\
& of chemical energy) \\
\midrule
% grid electricity & 0.43\\
natural gas & 190\\
refinery gas & 200\\
ethane & 200\\
LPG & 210\\
jet kerosene & 240\\
petrol & 240\\
gas/diesel oil & 250\\
heavy fuel oil & 260\\
naptha & 260\\
coking coal & 300\\
coal & 300\\
petroleum coke & 340\\
\bottomrule
\end{tabular}
% 240 g per km to 1 kWh per km
% 240 g per km to 100 kWh per 100 km
}{
\caption[a]{
Emissions associated with fuel combustion.\index{data!carbon intensity of fuels}\index{emissions!of fuels}
Source:
% http://www.defra.gov.uk/environment/business/envrp/gas/index.htm
DEFRA's Environmental
Reporting Guidelines for Company Reporting on Greenhouse
Gas Emissions.
}\label{DefraC}
}
\end{myfloat}
% 1 litre of gasoline comes from 23.5 tonnes of organic matter.
% the Use rate of fossil fuels now corresponds to 422 times
% the ancient laying-down rate of fossil fuels.
\begin{figure}
\figuremargin{
\begin{center}
{\mbox{\epsfxsize=\textwidth\epsfbox{../../data/humandev/CvG.eps}}}%
\end{center}
}{
\caption[a]{Greenhouse-gas emissions per capita, versus
\ind{GDP}\index{data!greenhouse gas emissions}\index{world}\index{countries}\index{data!GDP}
per capita, in purchasing-power-parity US dollars.
Squares show countries having
``high human development;'' circles,
``medium'' or ``low.''
See also figures \ref{fig.En1} (\pref{fig.En1}) and \ref{fig.En2} (\pref{fig.En2}).
Source:
UNDP Human Development Report, 2007.
\tinyurlb{3av4s9}{http://hdr.undp.org/en/statistics/}
}\label{fig.En55}
}
\end{figure}
\begin{figure}
\fullwidthfigure{
\begin{center}
{\mbox{\epsfxsize=\fulltextwidth\epsfbox{../../data/humandev/CvE.eps}}}%
\end{center}
}{
\caption[a]{Greenhouse-gas emissions per capita, versus
power consumption per capita\index{data!energy consumption}%
\index{data!greenhouse gas emissions}\index{world}\index{countries}.
The lines show the emission-intensities of coal and natural gas.
Squares show countries having
``high human development;'' circles,
``medium'' or ``low.''
See also figures \ref{fig.En1} (\pref{fig.En1}) and \ref{fig.En2} (\pref{fig.En2}).
Source:
UNDP Human Development Report, 2007.
% \tinyurlb{3av4s9}{http://hdr.undp.org/en/statistics/}
}\label{fig.En66}
}
\end{figure}
\clearpage
%\section{Quick reference -- conversion factors}
%\section{standards.tex}
%\input{standards.tex}
\chtweak\chtweak\chtweak\chtweak\chtweak
%\bset\chapter{\bcol{Terminology}}
%\input{terminology.tex}
\bset\chapter{\bcol{Populations and areas}}
\label{ch.area2}
\begin{figure}[!b]
\figuremargin{
\begin{center}
\mono%
{\includegraphics[width=116mm]{../data/plot2.ps}}%
{\includegraphics[width=116mm]{../data/plot2c.ps}}%
\end{center}
}{
\caption[a]{Populations and areas of countries
and regions of the world.
Both scales are logarithmic.
Each sloping line identifies a population density;
countries with highest population density
are towards the lower right, and lower population
densities are towards the upper left.
These data are provided in tabular form on
\pref{tab.areas1}.\index{area per person}
% in
% \chref{ch.area2} (\pref{ch.area2}).
}
\label{fig.areas}
}
\end{figure}
\section{Population densities}
Figure \ref{fig.areas}\label{pDensities}
% and \ref{fig.areas}
shows the areas of various regions
% countries and collections of countries
versus their populations.
Diagonal lines on this diagram\index{data!countries}\index{data!population}\index{data!area}
are lines of constant population density.
\ind{Bangladesh}, on the rightmost-but-one
diagonal, has a population density of
1000 per square kilometre; India, England, the Netherlands,
and \ind{Japan} have population densities one third that: about
350 per km$^2$. Many \ind{Europe}an countries have about 100 per km$^2$.
At the other extreme, Canada, \ind{Australia},
and \ind{Libya} have population densities
of about 3 people per km$^2$.
The central diagonal line marks the population density of the
\ind{world}: 43 people per square kilometre.
\ind{America} is an average country from
this point of view:\index{area per person}
the 48 contiguous states of the
USA have the same population density
as the world.
Regions that are notably rich
in area, and whose population density is
below the average, include
Russia, Canada, Latin America,
Sudan, Algeria, and Saudi Arabia.
Of these large, area-rich countries, some
that are close to Britain, and
with whom Britain might therefore wish to be
friendly, are
\ind{Kazakhstan}, Libya, \ind{Saudi Arabia}, \ind{Algeria},
and \ind{Sudan}.
%% could include Russia but they don't have sun?
\begin{figure}
\figuremargin{
\begin{center}
\mono%
{\includegraphics[width=116mm]{../data/plot1.ps}}%
{\includegraphics[width=116mm]{../data/plot1c.ps}}%
%%\mbox{\epsfbox{../data/plot2.ps}}
\end{center}
}{
\caption[a]{Populations and areas of countries
and regions of the world.
Both scales are logarithmic.\index{area per person}
Sloping lines are lines of constant population
density.
This figure shows detail from \figref{fig.areas}
(\pref{fig.areas}).
These data are provided in tabular form on
\pref{tab.areas1}.
}
\label{fig.areas2}
}
\end{figure}
\label{countriesD}
\begin{table}[htbp]
\figuremargin{
\begin{tabular}{lrrrr} \toprule
Region & Population & Land area & People & Area each \\
& & (km$^2$) & per km$^2$ & (m$^2$) \\ \midrule
%%## by pop
World & {{6\,440\,000\,000}} & {{148\,000\,000}} & {{ 43}} & {{ 23\,100}} \\
Asia & {{3\,670\,000\,000}} & {{44\,500\,000}} & {{ 82}} & {{ 12\,100}} \\
Africa & {{778\,000\,000}} & {{30\,000\,000}} & {{ 26}} & {{ 38\,600}} \\
Europe & {{732\,000\,000}} & {{ 9\,930\,000}} & {{ 74}} & {{ 13\,500}} \\
North America\hspace*{-0.051in} & {{483\,000\,000}} & {{24\,200\,000}} & {{ 20}} & {{ 50\,200}} \\
Latin America\hspace*{-0.051in} & {{342\,000\,000}} & {{17\,800\,000}} & {{ 19}} & {{ 52\,100}} \\
Oceania & 31\,000\,000 & {{ 7\,680\,000}} & {{ 4}} & {{ 247\,000}} \\
Antarctica & 4\,000 & {{13\,200\,000}} \\
% & {{ 0.0003}} & {{3\,300\,000\,000}} \\
\bottomrule \end{tabular}
}{
\caption[a]{Population densities of the continents.
These data are displayed graphically in figures \ref{fig.areas} and \ref{fig.areas2}. Data are from 2005.
% (\pref{fig.areas}).
}
}
\end{table}
\clearpage
\begin{figure}[htbp]
%\figuredangle{
\fullwidthfigure{
%\begin{center}
\begin{tabular}{@{}c@{\hspace*{-0.2in}}c@{}}
\mono%
{\includegraphics[height=3.7in]{../data/USAstates1.eps}}%
{\includegraphics[height=3.7in]{../data/USAstates1c.eps}}%
&
%% see gnue and gnu3
\mono%
{\includegraphics[height=3.7in]{../data/mono/plotEU.eps}}%
{\includegraphics[height=3.7in]{../data/plotEU.eps}}%
% the second figure runs out on the rhs a bit?
\\
\end{tabular}
%\end{center}
}{
\caption[a]{Populations and areas of the States of America\index{area per person}
and {regions around Europe}. }
% and a few related regions.}
% (Cut this from the UK edition.)}
\label{fig.areasEU}
\label{fig.areasUSA}
}
\end{figure}
%\vfill
\label{countriesA}
% alphabetical order - from countries.tex
% for full list see ../data/countries.tex0 and countries
% method ./sorter.p < countries >> countries.tex
\begin{table}
\fullwidthfigure{
{\scriptsize
\begin{tabular}{@{}ll@{}}
\begin{tabular}{lrrrr} \toprule
Region & Population & Area & People & Area \\
& & & per & per \\
& & & km$^2$ & person \\
& & (km$^2$) & & (m$^2$) \\
\midrule
Afghanistan & 29\,900\,000 & 647\,000 & {{ 46}} & {{ 21\,600}} \\
Africa & {\bf{778\,000\,000}} & {\bf{30\,000\,000}} & {{ 26}} & {{ 38\,600}} \\
Alaska & 655\,000 & 1\,480\,000 & {{ 0.44}} & {{ 2\,260\,000}} \\
Albania & 3\,560\,000 & 28\,700 & {{ 123}} & {{ 8\,060}} \\
Algeria & 32\,500\,000 & 2\,380\,000 & {{ 14}} & {{ 73\,200}} \\
%America (ex.\ Alaska)\hspace*{-0.2in}
Angola & 11\,100\,000 & 1\,240\,000 & {{ 9}} & {{ 111\,000}} \\
Antarctica & 4\,000 & {\bf{13\,200\,000}} \\
Argentina & 39\,500\,000 & 2\,760\,000 & {{ 14}} & {{ 69\,900}} \\
Asia & {\bf{3\,670\,000\,000}} & {\bf{44\,500\,000}} & {{ 82}} & {{ 12\,100}} \\
Australia & 20\,000\,000 & {\bf{ 7\,680\,000}} & {{ 2.6}} & {{ 382\,000}} \\
Austria & 8\,180\,000 & 83\,800 & {{ 98}} & {{ 10\,200}} \\
Bangladesh & {\bf{144\,000\,000}} & 144\,000 & {{ 1\,000}} & {{ 997}} \\
Belarus & 10\,300\,000 & 207\,000 & {{ 50}} & {{ 20\,100}} \\
Belgium & 10\,000\,000 & 31\,000 & 340 & 2\,945 \\
Bolivia & 8\,850\,000 & 1\,090\,000 & {{ 8}} & {{ 124\,000}} \\
Bosnia \& \makebox[0.4in][l]{Herzegovina} & 4\,020\,000 & 51\,100 & {{ 79}} & {{ 12\,700}} \\
Botswana & 1\,640\,000 & 600\,000 & {{ 2.7}} & {{ 366\,000}} \\
Brazil & {\bf{186\,000\,000}} & {\bf{ 8\,510\,000}} & {{ 22}} & {{ 45\,700}} \\
Bulgaria & 7\,450\,000 & 110\,000 & {{ 67}} & {{ 14\,800}} \\
CAR & 3\,790\,000 & 622\,000 & {{ 6}} & {{ 163\,000}} \\
Canada & 32\,800\,000 & {\bf{ 9\,980\,000}} & {{ 3.3}} & {{ 304\,000}} \\
Chad & 9\,820\,000 & 1\,280\,000 & {{ 8}} & {{ 130\,000}} \\
Chile & 16\,100\,000 & 756\,000 & {{ 21}} & {{ 46\,900}} \\
China & {\bf{1\,300\,000\,000}} & {\bf{ 9\,590\,000}} & {{ 136}} & {{ 7\,340}} \\
Colombia & 42\,900\,000 & 1\,130\,000 & {{ 38}} & {{ 26\,500}} \\
Croatia & 4\,490\,000 & 56\,500 & {{ 80}} & {{ 12\,500}} \\
Czech Republic & 10\,200\,000 & 78\,800 & {{ 129}} & {{ 7\,700}} \\
DRC & {\bf{60\,000\,000}} & 2\,340\,000 & {{ 26}} & {{ 39\,000}} \\
Denmark & 5\,430\,000 & 43\,000 & {{ 126}} & {{ 7\,930}} \\
Egypt & {\bf{77\,500\,000}} & 1\,000\,000 & {{ 77}} & {{ 12\,900}} \\
{England} & {49\,600\,000} & {130\,000} & {380} & {2\,630} \\
Estonia & 1\,330\,000 & 45\,200 & {{ 29}} & {{ 33\,900}} \\
Ethiopia & {\bf{73\,000\,000}} & 1\,120\,000 & {{ 65}} & {{ 15\,400}} \\
Europe & {\bf{732\,000\,000}} & {\bf{ 9\,930\,000}} & {{ 74}} & {{ 13\,500}} \\
European Union & {\bf{496\,000\,000}} & 4\,330\,000 & {{ 115}} & {{ 8\,720}} \\
Finland & 5\,220\,000 & 338\,000 & {{ 15}} & {{ 64\,700}} \\
France & {\bf{60\,600\,000}} & 547\,000 & {{ 110}} & {{ 9\,010}} \\
Gaza Strip & 1\,370\,000 & 360 & {{ 3\,820}} & {{ 261}} \\
Germany & {\bf{82\,400\,000}} & 357\,000 & {{ 230}} & {{ 4\,330}} \\
Greece & 10\,600\,000 & 131\,000 & {{ 81}} & {{ 12\,300}} \\
Greenland & 56\,300 & 2\,160\,000 & {{ 0.026}} & {{38\,400\,000}} \\
Hong Kong & 6\,890\,000 & 1\,090 & {{ 6\,310}} & {{ 158}} \\
Hungary & 10\,000\,000 & 93\,000 & {{ 107}} & {{ 9\,290}} \\
Iceland & 296\,000 & 103\,000 & {{ 2.9}} & {{ 347\,000}} \\
India & {\bf{1\,080\,000\,000}} & 3\,280\,000 & {{ 328}} & {{ 3\,040}} \\
Indonesia & {\bf{241\,000\,000}} & 1\,910\,000 & {{ 126}} & {{ 7\,930}} \\
Iran & {\bf{68\,000\,000}} & 1\,640\,000 & {{ 41}} & {{ 24\,200}} \\
Ireland & 4\,010\,000 & 70\,200 & {{ 57}} & {{ 17\,500}} \\
Italy & {\bf{58\,100\,000}} & 301\,000 & {{ 192}} & {{ 5\,180}} \\
Japan & {\bf{127\,000\,000}} & 377\,000 & {{ 337}} & {{ 2\,960}} \\
Kazakhstan & 15\,100\,000 & 2\,710\,000 & {{ 6}} & {{ 178\,000}} \\
Kenya & 33\,800\,000 & 582\,000 & {{ 58}} & {{ 17\,200}} \\
Latin America\hspace*{-0.2in} & {\bf{342\,000\,000}} & {\bf{17\,800\,000}} & {{ 19}} & {{ 52\,100}} \\
Latvia & 2\,290\,000 & 64\,500 & {{ 35}} & {{ 28\,200}} \\
Libya & 5\,760\,000 & 1\,750\,000 & {{ 3.3}} & {{ 305\,000}} \\
\bottomrule
\end{tabular}&
\begin{tabular}{lrrrr} \toprule
Region & Population & Area & People & Area \\
& & & per & per \\
& & & km$^2$ & person \\
& & (km$^2$) & & (m$^2$) \\
\midrule
~&\\
Lithuania & 3\,590\,000 & 65\,200 & {{ 55}} & {{ 18\,100}} \\
Madagascar & 18\,000\,000 & 587\,000 & {{ 31}} & {{ 32\,500}} \\
Mali & 12\,200\,000 & 1\,240\,000 & {{ 10}} & {{ 100\,000}} \\
Malta & 398\,000 & 316 & {{ 1\,260}} & {{ 792}} \\
Mauritania & 3\,080\,000 & 1\,030\,000 & {{ 3}} & {{ 333\,000}} \\
Mexico & {\bf{106\,000\,000}} & 1\,970\,000 & {{ 54}} & {{ 18\,500}} \\
Moldova & 4\,450\,000 & 33\,800 & {{ 131}} & {{ 7\,590}} \\
Mongolia & 2\,790\,000 & 1\,560\,000 & {{ 1.8}} & {{ 560\,000}} \\
Mozambique & 19\,400\,000 & 801\,000 & {{ 24}} & {{ 41\,300}} \\
Myanmar & 42\,900\,000 & 678\,000 & {{ 63}} & {{ 15\,800}} \\
Namibia & 2\,030\,000 & 825\,000 & {{ 2.5}} & {{ 406\,000}} \\
Netherlands & 16\,400\,000 & 41\,500 & {{ 395}} & {{ 2\,530}} \\
New Zealand & 4\,030\,000 & 268\,000 & {{ 15}} & {{ 66\,500}} \\
Niger & 11\,600\,000 & 1\,260\,000 & {{ 9}} & {{ 108\,000}} \\
Nigeria & {\bf{128\,000\,000}} & 923\,000 & {{ 139}} & {{ 7\,170}} \\
North America\hspace*{-0.2in} & {\bf{483\,000\,000}} & {\bf{24\,200\,000}} & {{ 20}} & {{ 50\,200}} \\
Norway & 4\,593\,000 & 324\,000 & 14 & 71\,000 \\
Oceania & 31\,000\,000 & {\bf{ 7\,680\,000}} & {{ 4}} & {{ 247\,000}} \\
Pakistan & {\bf{162\,000\,000}} & 803\,000 & {{ 202}} & {{ 4\,940}} \\
Peru & 27\,900\,000 & 1\,280\,000 & {{ 22}} & {{ 46\,000}} \\
Philippines & {\bf{87\,800\,000}} & 300\,000 & {{ 292}} & {{ 3\,410}} \\
Poland & 39\,000\,000 & 313\,000 & 124 & 8\,000 \\
Portugal & 10\,500\,000 & 92\,300 & {{ 114}} & {{ 8\,740}} \\
Republic of \makebox[0.4in][l]{Macedonia} & 2\,040\,000 & 25\,300 & {{ 81}} & {{ 12\,300}} \\
Romania & 22\,300\,000 & 237\,000 & {{ 94}} & {{ 10\,600}} \\
Russia & {\bf{143\,000\,000}} & {\bf{17\,000\,000}} & {{ 8}} & {{ 119\,000}} \\
Saudi Arabia & 26\,400\,000 & 1\,960\,000 & {{ 13}} & {{ 74\,200}} \\
Scotland & 5\,050\,000 & 78\,700 & {{ 64}} & {{ 15\,500}} \\
Serbia \& \makebox[0.4in][l]{Montenegro} & 10\,800\,000 & 102\,000 & {{ 105}} & {{ 9\,450}} \\
Singapore & 4\,420\,000 & 693 & {{ 6\,380}} & {{ 156}} \\
Slovakia & 5\,430\,000 & 48\,800 & {{ 111}} & {{ 8\,990}} \\
Slovenia & 2\,010\,000 & 20\,200 & {{ 99}} & {{ 10\,000}} \\
Somalia & 8\,590\,000 & 637\,000 & {{ 13}} & {{ 74\,200}} \\
South Africa & 44\,300\,000 & 1\,210\,000 & {{ 36}} & {{ 27\,500}} \\
South Korea & 48\,400\,000 & 98\,400 & {{ 491}} & {{ 2\,030}} \\
Spain & 40\,300\,000 & 504\,000 & {{ 80}} & {{ 12\,500}} \\
Sudan & 40\,100\,000 & 2\,500\,000 & {{ 16}} & {{ 62\,300}} \\
Suriname & 438\,000 & 163\,000 & {{ 2.7}} & {{ 372\,000}} \\
Sweden & 9\,000\,000 & 449\,000 & {{ 20}} & {{ 49\,900}} \\
Switzerland & 7\,480\,000 & 41\,200 & {{ 181}} & {{ 5\,510}} \\
Taiwan & 22\,800\,000 & 35\,900 & {{ 636}} & {{ 1\,570}} \\
Tanzania & 36\,700\,000 & 945\,000 & {{ 39}} & {{ 25\,700}} \\
Thailand & {\bf{65\,400\,000}} & 514\,000 & {{ 127}} & {{ 7\,850}} \\
Turkey & {\bf{69\,600\,000}} & 780\,000 & {{ 89}} & {{ 11\,200}} \\
Ukraine & 47\,400\,000 & 603\,000 & {{ 78}} & {{ 12\,700}} \\
{\em\textbf{United Kingdom}}& {\bf{59\,500\,000}} & {\em\textbf{244\,000}} & {{\em\textbf{243}}} & {\em\textbf{ 4\,110}} \\
USA (ex.\ Alaska)\hspace*{-0.2in} & {\bf{295\,000\,000}} & {\bf{ 8\,150\,000}} & {{ 36}} & {{ 27\,600}} \\
Venezuela & 25\,300\,000 & 912\,000 & {{ 28}} & {{ 35\,900}} \\
Vietnam & {\bf{83\,500\,000}} & 329\,000 & {{ 253}} & {{ 3\,940}} \\
Wales & 2\,910\,000 & 20\,700 & {{ 140}} & {{ 7\,110}} \\
Western Sahara & 273\,000 & 266\,000 & {{ 1}} & {{ 974\,000}} \\
World & {\bf{6\,440\,000\,000}} & {\bf{148\,000\,000}} & {{ 43}} & {{ 23\,100}} \\
Yemen & 20\,700\,000 & 527\,000 & {{ 39}} & {{ 25\,400}} \\
Zambia & 11\,200\,000 & 752\,000 & {{ 15}} & {{ 66\,800}} \\
%%%%%%%%%
%\midrule
%%%%%%%%%%
% World & {\bf{6\,440\,000\,000}} & {\bf{148\,000\,000}} & {{ 43}} & {{ 23\,100}} \\
%%%%%%%%%
%\midrule
%%%%%%%%%%
\bottomrule
\end{tabular}\\
\end{tabular}
}}{
\caption[a]{Regions and their population densities.
% (alphabetical order).
Populations above 50 million and areas greater than 5 million \km$^2$
are highlighted.\index{area per person}
These data are displayed graphically in \figref{fig.areas} (\pref{fig.areas}).
Data are from 2005.
}\label{tab.areas1}
}
\end{table}
\bset\chapter{\bcol{UK energy history}}
\label{ch.ukeh}
\setcounter{topnumber}{5}%
\setcounter{totalnumber}{5}%
\setcounter{bottomnumber}{5}%
\begin{table}[htbp]
\figuremargin{\small
\begin{tabular}{lcc} \toprule
Primary fuel& kWh/d/p& \kWhe/d/p \\ \midrule % Mtoe/y (2004)\\ \midrule
Oil & 43 \\% 81 \\
Natural gas & 47 \\% 88\\
Coal & 20 \\% 38\\
Nuclear & \phantom{0}9 &\multicolumn{1}{@{$\rightarrow$}r}{3.4} \\% 18\\
% In dukes 07, nuclear supplied 75.5TWh (2006)
% dukes lists 17.1Mtoe (9.12kWh/d/p) which comes from 75.5*0.085985/0.38
Hydro & & \multicolumn{1}{@{}r}{0.2} \\% 0.9kWh/d/p - in BP units 1.7\\ hydro 3.7TWh in dukes07 (2006)
%% Was 0.17 Is it not 0.19 in dukes07 ??? see current.tex, yes, infact 0.21
Other renewables & & \multicolumn{1}{@{}r}{0.8} \\
\bottomrule
\end{tabular}
%% I think BP use a different multiplier to value electricity from eg hydro
%% (This doesn't include import of electricity from France, I assume)
}{
\caption[a]{
Breakdown of primary energy sources in the UK (2004--2006).
% Redo in kWh/d per person? YES.
}
\label{tab.breakdownP}
}
\end{table}
\begin{figure}[htbp]
\figuremargin{
\begin{center}
\mbox{\epsfxsize=53mm\epsfbox{../data/ukelec.eps}}
\mbox{\epsfxsize=53mm\epsfbox{../data/EdFGap.eps}} \\[-0.1in]
\end{center}
}{
% COLON
\caption[a]{Left: UK net electricity supplied, by source,
in kWh per day per person.\index{electricity!supply}
(Another 0.9\,kWh/d/p is generated and used by the
generators themselves.)%
\index{data!electricity production}\index{UK electricity production}
% and there's imports too. from france
Right:
the \ind{energy gap} created by UK \ind{power station} closures,
as projected by energy company \ind{EdF}.
This graph shows the predicted {\em{capacity}\/} of nuclear, coal, and oil
power stations, in kilowatt-hours per day per person.\index{data!electrical generation capacity}\index{nuclear!capacity}\index{nuclear!power station closures}\index{coal!power station closures}\index{data!energy gap}
The capacity is the maximum deliverable power of a source.
% This graph shows the % in kWh per day per person.
% and there's imports too. from france
}
\label{fig.Gap2}\label{fig.ukelec}
}
\end{figure}
\begin{figure}[htbp]
\figuremargin{
\begin{center}
\begin{tabular}{c}
{\mbox{\epsfysize=1.9in\epsfbox{../../data/NationalGrid/colo/Jan1.eps}}}%
\\[-0.1in]
\end{tabular}
\end{center}
}{
\caption[a]{Electricity demand\index{demand!electricity}
in Great Britain
(in kWh/d per person)\index{Britain!electricity demand}
during two winter
weeks of 2006.\index{data!electricity demand}
The peaks in January are at 6pm each day.
(If you'd like
to obtain the national demand in GW, the top of the scale,
24\,kWh/d per person, is the same as 60\,GW per UK.)
}
\label{fig.demand22}
}
\end{figure}
\begin{table}[!b]\figuremargin{\scriptsize% small%
\begin{tabular}{cccc} \toprule
& 2006 & 2007 \\ \midrule
``Primary units'' (the first 2\,kWh/d) & 10.73\,p/kWh & 17.43\,p/kWh \\
``Secondary units'' (the rest) & \ 8.13\,p/kWh & \ 9.70\,p/kWh\\
\bottomrule
\end{tabular}
}{
\caption[a]{Domestic electricity charges (2006, 2007) for
\ind{Powergen} customers in Cambridge, including tax.
}
\label{tab.domestic.elecHC}
}
\end{table}
\clearpage
\begin{myfloat}
\threefigures{
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm\epsfbox{../data/UKgas/hydronuc.eps}} \\
\end{tabular}
}{
\caption[a]{History of UK production of electricity,
hydroelectricity, and nuclear electricity.%
\index{hydroelectricity production}\index{data!hydroelectricity}\index{data!nuclear power}
Powers are expressed ``per person'' by dividing each power
by 60 million.
}
}{
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm\epsfbox{../data/UKgas/fossilfuelgas.eps}}\\
\end{tabular}
}{
\caption[a]{
History of UK use of fossil fuels for electricity production.\index{data!electricity production}\index{data!fossil fuels}\index{UK electricity production}\index{electricity production}
Powers are expressed ``per person'' by dividing each power
by 60 million.
}\label{fig.ffgas}
}{
\begin{tabular}{@{}c@{}}
\mbox{\epsfxsize=53mm\epsfbox{../data/UKgas/coalgas.eps}} \\
\end{tabular}
}{
\caption[a]{
UK production and imports of coal,
and UK consumption of gas.\index{data!coal imports}\index{data!coal production}\index{data!gas consumption}\index{gas consumption}\index{coal production}\index{coal imports}\index{imports!coal}
Powers are expressed ``per person'' by dividing each power
by 60 million.
} \label{fig.ukcoalgas}
}
\end{myfloat}
% added material Sat 4/10/08
% \input{EPC.tex}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% the book's end
\fakesection{this file contains a list of commands for the index}
\index{ROC|see{renewables obligation certificate}}
\index{CPV|see{concentrator photovoltaics}}
\index{CO$_2$|see{carbon dioxide}}
\index{CSP|see{concentrating solar power}}
\index{GHG|see{greenhouse gas}}
\index{HVDC|see{high voltage DC}}
\index{VLS-PV|see{very large scale photovoltaics}}
\index{LCA|see{lifecycle analysis}}
\index{URL|see{web pointer}}
\index{automobile|see{car}}
\index{United Kingdom|see{UK}}
\index{power per unit area|see{power density}}
\index{tonne|see{ton}}
\nocite{KingI}
\index{Boeing 747|see{747}}
\index{Britain|see{UK}}
\index{England|seealso{UK}}
\index{Scotland|seealso{UK}}
\index{jumbo jet|see{747}}
\index{USA|seealso{America}}
\index{America|seealso{USA}}
\index{boat|seealso{ship}}
\index{CCS|seealso{carbon capture and storage}}
\index{fallacy|seealso{myth}}
\index{CHP|see{combined heat and power}}
\addtocontents{toc}{\protect\addvspace{10pt}}
% \newpage
\subchaptercontents{List of web links}% i.e. gets included in the contents
\label{urllist}
This section lists the full links corresponding to each of
the tiny URLs mentioned in the text. Each item starts with the page number
on which the tiny URL was mentioned.\index{tinyURL}
See also
\url{http://tinyurl.com/yh8xse} (or
\url{www.inference.phy.cam.ac.uk/sustainable/book/tex/cft.url.html})
for a clickable page with all URLs in this book.
If you find a URL doesn't work any more,
you may be able to find the page on
the Wayback Machine internet archive
\tinyurl{f754}{http://www.archive.org/web/web.php}.
\medskip\par
\renewcommand\descriptionlabel[1]%
{\hspace{\labelsep}\textsf{#1}}
\beginfullpagewidth%
\scriptsize
%\begin{description}%% perhaps a good idea to define a special list for this
\urlstyle{leoscript}% make urls smaller see texdefns
\begin{urlslist}
\item[] \
\item[p \hfill tinyURL] Full web link.
\item [\NoteColor {\pageref {ydoobr} \hfill {\tt {ydoobr}}}] {\protect \url {www.bbc.co.uk/radio4/news/anyquestions_transcripts_20060127.shtml}}
\item [\NoteColor {\pageref {2jhve6} \hfill {\tt {2jhve6}}}] {\protect \url {www.ft.com/cms/s/0/48e334ce-f355-11db-9845-000b5df10621.html}}
\item [\NoteColor {\pageref {25e59w} \hfill {\tt {25e59w}}}] {\protect \url {news.bbc.co.uk/1/low/uk_politics/7135299.stm}}
\item [\NoteColor {\pageref {5o7mxk} \hfill {\tt {5o7mxk}}}] {\protect \url {www.guardian.co.uk/environment/2007/dec/10/politics}}
\item [\NoteColor {\pageref {5c4olc} \hfill {\tt {5c4olc}}}] {\protect \url {www.foe.co.uk/resource/press_releases/green_solutions_undermined_10012008.html}}
\item [\NoteColor {\pageref {2fztd3} \hfill {\tt {2fztd3}}}] {\protect \url {www.jalopnik.com/cars/ alternative-energy/ now-thats-some-high-quality- h20-car-runs-on-water-177788.php}}
\item [\NoteColor {\pageref {26e8z} \hfill {\tt {26e8z}}}] {\protect \url {news.bbc.co.uk/1/hi/sci/tech/3381425.stm}}
\item [\NoteColor {\pageref {ykhayj} \hfill {\tt {ykhayj}}}] {\protect \url {politics.guardian.co.uk/terrorism/story/0,,1752937,00.html}}
\item [\NoteColor {\pageref {l6y5g} \hfill {\tt {l6y5g}}}] {\protect \url {www.grida.no/climate/ipcc_tar/wg1/fig3-1.htm}}
\item [\NoteColor {\pageref {5qfkaw} \hfill {\tt {5qfkaw}}}] {\protect \url {www.nap.edu/catalog.php?record_id=12181}}
\item [\NoteColor {\pageref {2z2xg7} \hfill {\tt {2z2xg7}}}] {\protect \url {assets.panda.org/downloads/2_vs_3_degree_impacts_1oct06_1.pdf}}
\item [\NoteColor {\pageref {yyxq2m} \hfill {\tt {yyxq2m}}}] {\protect \url {www.bp.com/genericsection.do?categoryId=93&contentId=2014442}}
\item [\NoteColor {\pageref {dzcqq} \hfill {\tt {dzcqq}}}] {\protect \url {www.defra.gov.uk/environment/climatechange/internat/pdf/avoid-dangercc.pdf}}
\item [\NoteColor {\pageref {y98ys5} \hfill {\tt {y98ys5}}}] {\protect \url {news.bbc.co.uk/1/hi/business/4933190.stm}}
\item [\NoteColor {\pageref {5647rh} \hfill {\tt {5647rh}}}] {\protect \url {www.dft.gov.uk/pgr/statistics/datatablespublications/tsgb/}}
\item [\NoteColor {\pageref {27jdc5} \hfill {\tt {27jdc5}}}] {\protect \url {www.dft.gov.uk/pgr/statistics/datatablespublications/ energyenvironment/ tsgb-chapter3energyandtheenvi1863}}
\item [\NoteColor {\pageref {28abpm} \hfill {\tt {28abpm}}}] {\protect \url {corporate.honda.com/environmentology/}}
\item [\NoteColor {\pageref {nmn4l} \hfill {\tt {nmn4l}}}] {\protect \url {www.simetric.co.uk/si_liquids.htm}}
\item [\NoteColor {\pageref {2hcgdh} \hfill {\tt {2hcgdh}}}] {\protect \url {cta.ornl.gov/data/appendix_b.shtml}}
\item [\NoteColor {\pageref {vxhhj} \hfill {\tt {vxhhj}}}] {\protect \url {www.cl.cam.ac.uk/research/dtg/weather/}}
\item [\NoteColor {\pageref {tdvml} \hfill {\tt {tdvml}}}] {\protect \url {www.phy.hw.ac.uk/resrev/aws/awsarc.htm}}
\item [\NoteColor {\pageref {3fbufz} \hfill {\tt {3fbufz}}}] {\protect \url {www.ipcc.ch/ipccreports/sres/aviation/004.htm}}
\item [\NoteColor {\pageref {3asmgy} \hfill {\tt {3asmgy}}}] {\protect \url {news.independent.co.uk/uk/transport/article324294.ece}}
\item [\NoteColor {\pageref {9ehws} \hfill {\tt {9ehws}}}] {\protect \url {www.boeing.com/commercial/747family/technical.html}}
\item [\NoteColor {\pageref {3exmgv} \hfill {\tt {3exmgv}}}] {\protect \url {www.ryanair.com/site/EN/about.php?page=About&sec=environment}}
\item [\NoteColor {\pageref {yrnmum} \hfill {\tt {yrnmum}}}] {\protect \url {www.grida.no/climate/ipcc/aviation/124.htm}}
\item [\NoteColor {\pageref {36w5gz} \hfill {\tt {36w5gz}}}] {\protect \url {www.rolls-royce.com/community/downloads/environment04/products/air.html}}
\item [\NoteColor {\pageref {2rqloc} \hfill {\tt {2rqloc}}}] {\protect \url {www.metoffice.gov.uk/climate/uk/location/scotland/index.html}}
\item [\NoteColor {\pageref {2szckw} \hfill {\tt {2szckw}}}] {\protect \url {www.metoffice.gov.uk/climate/uk/stationdata/cambridgedata.txt}}
\item [\NoteColor {\pageref {5hrxls} \hfill {\tt {5hrxls}}}] {\protect \url {eosweb.larc.nasa.gov/cgi-bin/sse/sse.cgi?+s01}}
\item [\NoteColor {\pageref {6z9epq} \hfill {\tt {6z9epq}}}] {\protect \url {www.solarcentury.com/knowledge_base/images/solar_pv_orientation_diagram}}
\item [\NoteColor {\pageref {2tl7t6} \hfill {\tt {2tl7t6}}}] {\protect \url {www.reuk.co.uk/40-Percent-Efficiency-PV-Solar-Panels.htm}}
\item [\NoteColor {\pageref {6hobq2} \hfill {\tt {6hobq2}}}] {\protect \url {www.azonano.com/news.asp?newsID=4546}}
\item [\NoteColor {\pageref {2lsx6t} \hfill {\tt {2lsx6t}}}] {\protect \url {www.udel.edu/PR/UDaily/2008/jul/solar072307.html}}
\item [\NoteColor {\pageref {62ccou} \hfill {\tt {62ccou}}}] {\protect \url {www.nrel.gov/news/press/2008/625.html}}
\item [\NoteColor {\pageref {5hzs5y} \hfill {\tt {5hzs5y}}}] {\protect \url {www.ens-newswire.com/ens/dec2007/2007-12-26-093.asp}}
\item [\NoteColor {\pageref {39z5m5} \hfill {\tt {39z5m5}}}] {\protect \url {news.bbc.co.uk/1/hi/world/europe/6505221.stm}}
\item [\NoteColor {\pageref {2uk8q8} \hfill {\tt {2uk8q8}}}] {\protect \url {www.powerlight.com/about/press2006_page.php?id=59}}
\item [\NoteColor {\pageref {2ahecp} \hfill {\tt {2ahecp}}}] {\protect \url {www.aps.org/meetings/multimedia/upload/ The_Status_and_Outlook_for_the_Photovoltaics_Industry_David_E_Carlson.pdf}}
\item [\NoteColor {\pageref {6kqq77} \hfill {\tt {6kqq77}}}] {\protect \url {www.defra.gov.uk/erdp/pdfs/ecs/miscanthus-guide.pdf}}
\item [\NoteColor {\pageref {ynjzej} \hfill {\tt {ynjzej}}}] {\protect \url {www.aceee.org/conf/06modeling/azevado.pdf}}
\item [\NoteColor {\pageref {wbd8o} \hfill {\tt {wbd8o}}}] {\protect \url {www.ref.org.uk/energydata.php}}
\item [\NoteColor {\pageref {b25e59w} \hfill {\tt {25e59w}}}] {\protect \url {news.bbc.co.uk/1/low/uk_politics/7135299.stm}}
\item [\NoteColor {\pageref {2t2vjq} \hfill {\tt {2t2vjq}}}] {\protect \url {www.guardian.co.uk/environment/2007/dec/11/windpower.renewableenergy}}
\item [\NoteColor {\pageref {57984r} \hfill {\tt {57984r}}}] {\protect \url {www.businessgreen.com/business-green/news/2205496/critics-question-government}}
\item [\NoteColor {\pageref {6oc3ja} \hfill {\tt {6oc3ja}}}] {\protect \url {www.independent.co.uk/environment/green-living/ donnachadh-mccarthy-my-carbonfree-year-767115.html}}
\item [\NoteColor {\pageref {5soql2} \hfill {\tt {5soql2}}}] {\protect \url {www.housebuildersupdate.co.uk/2006/12/eco-bollocks-award-windsave-ws1000.html}}
\item [\NoteColor {\pageref {6g2jm5} \hfill {\tt {6g2jm5}}}] {\protect \url {www.carbontrust.co.uk/technology/technologyaccelerator/small-wind}}
\item [\NoteColor {\pageref {5h69fm} \hfill {\tt {5h69fm}}}] {\protect \url {www.thepoultrysite.com/articles/894/economic-approach-to-broiler-production}}
\item [\NoteColor {\pageref {5pwojp} \hfill {\tt {5pwojp}}}] {\protect \url {www.fertilizer.org/ifa/statistics/STATSIND/pkann.asp}}
\item [\NoteColor {\pageref {5bj8k3} \hfill {\tt {5bj8k3}}}] {\protect \url {www.walkerscarbonfootprint.co.uk/walkers_carbon_footprint.html}}
\item [\NoteColor {\pageref {3s576h} \hfill {\tt {3s576h}}}] {\protect \url {www.permatopia.com/transportation.html}}
\item [\NoteColor {\pageref {6xrm5q} \hfill {\tt {6xrm5q}}}] {\protect \url {www.edf.fr/html/en/decouvertes/voyage/usine/retour-usine.html}}
\item [\NoteColor {\pageref {yx7zm4} \hfill {\tt {yx7zm4}}}] {\protect \url {www.cancentral.com/funFacts.cfm}}
\item [\NoteColor {\pageref {r22oz} \hfill {\tt {r22oz}}}] {\protect \url {www-materials.eng.cam.ac.uk/mpsite/interactive_charts/energy-cost/NS6Chart.html}}
\item [\NoteColor {\pageref {yhrest} \hfill {\tt {yhrest}}}] {\protect \url {www.transportation.anl.gov/pdfs/TA/106.pdf}}
\item [\NoteColor {\pageref {y5as53} \hfill {\tt {y5as53}}}] {\protect \url {www.aluminum.org/Content/NavigationMenu/The_Industry/Government_Policy/Energy/Energy.htm}}
\item [\NoteColor {\pageref {y2ktgg} \hfill {\tt {y2ktgg}}}] {\protect \url {www.ssab.com/templates/Ordinary____573.aspx}}
\item [\NoteColor {\pageref {6lbrab} \hfill {\tt {6lbrab}}}] {\protect \url {www.lindenau-shipyard.de/pages/newsb.html}}
\item [\NoteColor {\pageref {5ctx4k} \hfill {\tt {5ctx4k}}}] {\protect \url {www.wilhelmsen.com/SiteCollectionDocuments/WW_Miljorapport_engelsk.pdf}}
\item [\NoteColor {\pageref {yqbzl3} \hfill {\tt {yqbzl3}}}] {\protect {www.normanbaker.org.uk/downloads/Supermarkets Report Final Version.doc}}
\item [\NoteColor {\pageref {yttg7p} \hfill {\tt {yttg7p}}}] {\protect \url {budget2007.treasury.gov.uk/page_09.htm}}
\item [\NoteColor {\pageref {fcqfw} \hfill {\tt {fcqfw}}}] {\protect \url {www.mod.uk/DefenceInternet/AboutDefence/Organisation/KeyFactsAboutDefence/DefenceSpending.htm}}
\item [\NoteColor {\pageref {2e4fcs} \hfill {\tt {2e4fcs}}}] {\protect \url {press.homeoffice.gov.uk/press-releases/security-prebudget-report}}
\item [\NoteColor {\pageref {33x5kc} \hfill {\tt {33x5kc}}}] {\protect \url {www.mod.uk/NR/rdonlyres/95BBA015-22B9-43EF-B2DC-DFF14482A590/0/gep_200708.pdf}}
\item [\NoteColor {\pageref {35ab2c} \hfill {\tt {35ab2c}}}] {\protect \url {www.dasa.mod.uk/natstats/ukds/2007/c1/table103.html}}
\item [\NoteColor {\pageref {yg5fsj} \hfill {\tt {yg5fsj}}}] {\protect \url {siteresources.worldbank.org/DATASTATISTICS/Resources/GDP.pdf}}
\item [\NoteColor {\pageref {yfgjna} \hfill {\tt {yfgjna}}}] {\protect \url {www.sipri.org/contents/milap/milex/mex_major_spenders.pdf/download}}
\item [\NoteColor {\pageref {slbae} \hfill {\tt {slbae}}}] {\protect \url {www.wisconsinproject.org/countries/israel/plut.html}}
\item [\NoteColor {\pageref {yh45h8} \hfill {\tt {yh45h8}}}] {\protect \url {www.usec.com/v2001_02/HTML/Aboutusec_swu.asp}}
\item [\NoteColor {\pageref {t2948} \hfill {\tt {t2948}}}] {\protect \url {www.world-nuclear.org/info/inf28.htm}}
\item [\NoteColor {\pageref {2ywzee} \hfill {\tt {2ywzee}}}] {\protect \url {www.globalsecurity.org/wmd/intro/u-centrifuge.htm}}
\item [\NoteColor {\pageref {uzek2} \hfill {\tt {uzek2}}}] {\protect \url {www.dti.gov.uk/energy/inform/dukes/}}
\item [\NoteColor {\pageref {3av4s9} \hfill {\tt {3av4s9}}}] {\protect \url {hdr.undp.org/en/statistics/}}
\item [\NoteColor {\pageref {6frj55} \hfill {\tt {6frj55}}}] {\protect \url {news.independent.co.uk/environment/article2086678.ece}}
\item [\NoteColor {\pageref {5qhvcb} \hfill {\tt {5qhvcb}}}] {\protect \url {www.tramwayinfo.com/Tramframe.htm?www.tramwayinfo.com/tramways/Articles/Compair2.htm}}
\item [\NoteColor {\pageref {4qgg8q} \hfill {\tt {4qgg8q}}}] {\protect \url {www.newsweek.com/id/112733/output/print}}
\item [\NoteColor {\pageref {5o5x5m} \hfill {\tt {5o5x5m}}}] {\protect \url {www.cambridgeenergy.com/archive/2007-02-08/cef08feb2007kemp.pdf}}
\item [\NoteColor {\pageref {b5o5x5m} \hfill {\tt {5o5x5m}}}] {\protect \url {www.cambridgeenergy.com/archive/2007-02-08/cef08feb2007kemp.pdf}}
\item [\NoteColor {\pageref {5fbeg9} \hfill {\tt {5fbeg9}}}] {\protect \url {www.cfit.gov.uk/docs/2001/racomp/racomp/pdf/racomp.pdf}}
\item [\NoteColor {\pageref {679rpc} \hfill {\tt {679rpc}}}] {\protect \url {www.tfl.gov.uk/assets/downloads/environmental-report-2007.pdf}}
\item [\NoteColor {\pageref {5cp27j} \hfill {\tt {5cp27j}}}] {\protect \url {www.eaton.com/EatonCom/ProductsServices/Hybrid/SystemsOverview/HydraulicHLA/index.htm}}
\item [\NoteColor {\pageref {4wm2w4} \hfill {\tt {4wm2w4}}}] {\protect \url {www.citroenet.org.uk/passenger-cars/psa/berlingo/berlingo-electrique.html}}
\item [\NoteColor {\pageref {658ode} \hfill {\tt {658ode}}}] {\protect \url {www.greencarcongress.com/2008/02/mitsubishi-moto.html}}
\item [\NoteColor {\pageref {czjjo} \hfill {\tt {czjjo}}}] {\protect \url {corporate.honda.com/environment/fuel_cells.aspx?id=fuel_cells_fcx}}
\item [\NoteColor {\pageref {5a3ryx} \hfill {\tt {5a3ryx}}}] {\protect \url {automobiles.honda.com/fcx-clarity/specifications.aspx}}
\item [\NoteColor {\pageref {yok2nw} \hfill {\tt {yok2nw}}}] {\protect \url {www.eca.gov.uk/etl/find/_P_Heatpumps/ detail.htm?ProductID=9868& FromTechnology= S_WaterSourcePackaged}}
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\item [\NoteColor {\pageref {2fd8ar} \hfill {\tt {2fd8ar}}}] {\protect \url {www.geothermalint.co.uk/commercial/hydronicheatpumpranges.html}}
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\item [\NoteColor {\pageref {yebuk8} \hfill {\tt {yebuk8}}}] {\protect \url {www.dti.gov.uk/energy/sources/coal/index.html}}
\item [\NoteColor {\pageref {yhxf8b} \hfill {\tt {yhxf8b}}}] {\protect \url {www.worldenergy.org/wec-geis/publications/reports/ser/coal/coal.asp}}
\item [\NoteColor {\pageref {e2m9n} \hfill {\tt {e2m9n}}}] {\protect \url {www.coal.gov.uk/resources/cleanercoaltechnologies/ucgoverview.cfm}}
\item [\NoteColor {\pageref {5qntkb} \hfill {\tt {5qntkb}}}] {\protect \url {www.world-nuclear.org/info/reactors.htm}}
\item [\NoteColor {\pageref {y3wnzr} \hfill {\tt {y3wnzr}}}] {\protect \url {npc.sarov.ru/english/digest/132004/appendix8.html}}
\item [\NoteColor {\pageref {32t5zt} \hfill {\tt {32t5zt}}}] {\protect \url {web.ift.uib.no/~lillestol/Energy_Web/EA.html}}
\item [\NoteColor {\pageref {2qr3yr} \hfill {\tt {2qr3yr}}}] {\protect \url {documents.cern.ch/cgi-bin/setlink?base=generic&categ=public&id=cer-0210391}}
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\item [\NoteColor {\pageref {2k8y7o} \hfill {\tt {2k8y7o}}}] {\protect \url {www.nei.org/resourcesandstats/}}
\item [\NoteColor {\pageref {3pvf4j} \hfill {\tt {3pvf4j}}}] {\protect \url {www.sustainableconcrete.org.uk/main.asp?page=210}}
\item [\NoteColor {\pageref {4r7zpg} \hfill {\tt {4r7zpg}}}] {\protect \url {csereport2005.bluescopesteel.com/}}
\item [\NoteColor {\pageref {49hcnw} \hfill {\tt {49hcnw}}}] {\protect \url {www.ace.mmu.ac.uk/Resources/Fact_Sheets/Key_Stage_4/Waste/pdf/02.pdf}}
\item [\NoteColor {\pageref {3kduo7} \hfill {\tt {3kduo7}}}] {\protect \url {www.esrcsocietytoday.ac.uk/ESRCInfoCentre/facts/UK/index29.aspx?ComponentId=7104&SourcePageId=18130}}
\item [\NoteColor {\pageref {69vt8r} \hfill {\tt {69vt8r}}}] {\protect \url {www.osti.gov/energycitations/product.biblio.jsp?osti_id=7200593}}
\item [\NoteColor {\pageref {6oby22} \hfill {\tt {6oby22}}}] {\protect \url {www.osti.gov/energycitations/product.biblio.jsp?osti_id=6773271&query_id=0}}
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\item [\NoteColor {\pageref {shrln} \hfill {\tt {shrln}}}] {\protect \url {www.enviros.com/vrepository/}}
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\item [\NoteColor {\pageref {2n3pmb} \hfill {\tt {2n3pmb}}}] {\protect \url {www.dynamicdemand.co.uk/pdf_fridge_test.pdf}}
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\item [\NoteColor {\pageref {b5cp27j} \hfill {\tt {5cp27j}}}] {\protect \url {www.eaton.com/EatonCom/ProductsServices/Hybrid/SystemsOverview/HydraulicHLA/index.htm}}
\item [\NoteColor {\pageref {2sxlyj} \hfill {\tt {2sxlyj}}}] {\protect \url {www.batteryuniversity.com/partone-3.htm}}
\item [\NoteColor {\pageref {ktd7a} \hfill {\tt {ktd7a}}}] {\protect \url {www.vrbpower.com/docs/news/2006/20060830 - PR - Tapbury Sale - Ireland Windfarm.pdf}}
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\item [\NoteColor {\pageref {6eoyhg} \hfill {\tt {6eoyhg}}}] {\protect \url {news.bbc.co.uk/1/hi/uk/7215688.stm}}
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\item [\NoteColor {\pageref {32judd} \hfill {\tt {32judd}}}] {\protect \url {www.wildanimalsonline.com/birds/wanderingalbatross.php}}
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\item [\NoteColor {\pageref {br22oz} \hfill {\tt {r22oz}}}] {\protect \url {www-materials.eng.cam.ac.uk/mpsite/interactive_charts/energy-cost/NS6Chart.html}}
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\item [\NoteColor {\pageref {3b7zdf} \hfill {\tt {3b7zdf}}}] {\protect \url {www.communities.gov.uk/publications/planningandbuilding/generalizedlanduse}}
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\item [\NoteColor {\pageref {f754} \hfill {\tt {f754}}}] {\protect \url {www.archive.org/web/web.php}}
\end{urlslist}%
\ENDfullpagewidth
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% endmatter goes here
\addtocontents{toc}{\protect\addvspace{10pt}}
%\urlstyle{leotiny}% make urls really small see texdefns
\urlstyle{leoscript}% make urls smaller see texdefns
\small
\footnotesize
\clearpage
%
% BIBLIOGRAPHY
%
\begin{thebibliography}{220}
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\providecommand{\url}[1]{\texttt{#1}}
\expandafter\ifx\csname urlstyle\endcsname\relax
\providecommand{\doi}[1]{doi: #1}\else
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\bibitem[Zaleski(2005)]{Zaleski}
{\sc Zaleski, C.~P.}
\newblock (2005).
\newblock The future of nuclear power in {France}, the {EU} and the world for
the next quarter-century.
\newblock \url{www.npec-web.org/{\breakhere}Essays/{\breakhere}Essay050120 Zalenski - Future of
Nuclear Power.pdf}.
\newblock \url{tinyurl.com/32louu}.
\bibitem[Zhu et~al.(2008)Zhu, Long, and Ort]{ZhuLongOrt}
{\sc Zhu, X.-G.}, {\sc Long, S.~P.}, and {\sc Ort, D.~R.}
\newblock (2008).
\newblock What is the maximum efficiency with which photosynthesis can convert
solar energy into biomass?
\newblock \emph{Current Opinion in Biotechnology}, 19:\penalty0 153159.
\end{thebibliography}
\normalsize
%\newpage
% (preceded by bibs)
\newpage
\addtocontents{toc}{\protect\addvspace{10pt}}
% INDEX
% to get alternative alignment (so chapter titles aligned), use this:
% \addcontentsline{toc}{chapter}{\protect \numberline{}Index}
\addcontentsline{toc}{chapter}{Index}%
{\footnotesize\raggedright
\beginfullpagewidth%
\begin{theindex}
\item $\lambda$, 307
\item 13 amps, 50
\indexspace
\item 747, 128, 132, 269, 272, 275, 277, 282
\subitem flight record, 277
\item 1698, 6, 19
\item 1769, 6
\item 1910, 7
\item 1979, 20
\item 2050, 203
\indexspace
\item A380, 132
\item AA battery, 89
\item absolution, 3
\item academics, 293
\item accelerator-driven system, 166
\item action, 203
\item addiction, 203
\item Adelman, Kenneth, 40
\item advertisement, 72, 154
\item advertising standards authority, 126
\item advocating acts of consumption, 4
\item aerodynamic efficiency, 273
\item agricultural waste, 206
\item air changes, 289, 296
\item air freight
\subitem energy consumption, 92, 275
\item air resistance, 118
\item air travel
\subitem neutralization, 211
\item air, hot, 51
\item air-conditioning, 52, 144, 147, 151
\subitem in vehicles, 131
\item air-source heat pump, 52, 147, 151, 205, 212
\item Airbus, 132
\item Aircar, 129
\item aircraft, 132
\subitem turboprop, 35
\item aircraft carriers, 220
\item airship, 280
\item albatross, 272, 273
\item albedo flip, 243
\item Albert Hall, 332
\item alchemy, 88
\item algae, 285, 286, 288
\subitem biofuel, 285
\subitem hydrogen, 285
\item Algeria, 177, 338
\item alkaline battery
\subitem energy density, 199
\item Alps, 209
\item altitude, 272
\item altruism, 5
\item aluminium, 89, 97, 325
\subitem can, 89
\subitem embodied energy, 94
\subitem Iceland, 183
\item always on, 96
\item America, 21, 93, 338, \seealso{USA}{344}
\item American, 104, 234
\item Amonix, 182
\item amplifier, 70
\item amps, 50
\item analogy, 24
\item Andasol, 178, 184
\item answering machine, 70
\item any colour, as long as it is green, 122
\item apple, 259
\item Aptera, 137
\item Aquamarine Power Ltd, 310
\item area, 55, 332
\subitem frontal, 119
\item area per person, 32, 338--341
\item Argentina, 237
\item Arizona, 182, 236, 286
\item arms exports, 220
\item Artemis Intelligent Power, 125
\item artificial trees, 249
\item Atkinson cycle, 136
\item Atlantic, 73, 309
\item Atlantic Ocean
\subitem tides, 81
\subitem waves, 74
\item atmosphere, 10
\item Atoms for Peace, 133
\item Ausra, 184
\item Australia, 237, 338
\item automobile, \see{car}{344}
\item average travel, 30
\item average windspeeds, 32
\indexspace
\item B\&Q, 66
\item Bad Thing, 10
\item Baer, Paul, 15
\item bag of crisps, 80
\item bailing the Titanic, 68
\item balloon, 280
\item Bangladesh, 338
\item bar fire, 51
\item bar-tailed godwit, 277
\item Barbados, 230
\item barium titanate, 199
\item barley, 286
\item barrel of oil, 331
\item bath, 50, 51
\item bathymetry, 61
\item battery, 89, 137, 205
\subitem efficiency, 202
\subitem energy density, 199, 261
\subitem lithium-sulphur, 202
\subitem nickel-cadmium, 89
\subitem rechargeable, 94
\item battery charging, 197
\item battery exchange, 261
\item Bavaria, 41, 48, 216
\item BBC, 68, 71
\item beach, 307
\item Beatrice, 64, 66
\item Beaufort scale, 263
\item Bedford, 55
\item beef, 77
\item Belgium, 21, 208
\item Berlingo, 127
\item Betz, Albert, 264
\item bicycle, 119, 128, 258, 264
\item billiard ball, 81
\item billion, 11, 217, 329
\subitem nuclear decommissioning, 175
\item biodiesel, 42, 204
\subitem from algae, 285
\item bioethanol, 205
\subitem co-products, 284
\subitem from corn, 284
\subitem from sugar beet, 283
\subitem from sugar cane, 284
\item biofuel, 42, 78, 283
\subitem cellulosic ethanol, 284
\subitem from algae, 285
\subitem from corn, 284
\subitem jatropha, 284
\subitem power density, 283
\subitem production, 205
\subitem rape, 283
\subitem sugar beet, 283
\subitem sugar cane, 284
\item biomass, 38, 43
\subitem cofiring, 212
\subitem plantation, 212
\subitem yields, 48
\item biomethanol, 204
\item bird, 269
\subitem formation flying, 270, 278
\subitem longest flight, 277
\subitem range, 276
\subitem speed, 272
\subitem theory of, 269
\item birds and windmills, 63
\item Birmingham, 206
\item Blair, Tony, 213, 222, 230
\item blimp, 280
\item blob, 181, 221
\item block, 325
\item BMW, 29, 260
\subitem Hydrogen 7, 130, 139
\item boat, \seealso{ship}{344}
\subitem energy consumption, 92
\subitem nuclear-powered, 133
\item boats as planes, 279
\item Boeing 747, \see{747}{344}
\item Boltzmann, 272
\item bomb, 100, 101
\item Bombardier Q400, 35
\item boron, 19, 202, 209
\item boundary, 30
\item BP, 3, 27, 219
\item brakes, 255
\item braking, regenerative, 125
\item breeder reactor, 163, 165
\item brick, 325
\item Brinkley, Mark, 66
\item Bristol channel, 84
\item Britain, 21, 93
\subitem electricity demand, 186, 188, 342
\subitem heights, 55
\subitem rainfall, 55, 56
\item British Isles, 83
\item British person, 30
\item BritNed, 197
\item Brooklyn windmill, 264
\item Brown, Gordon, 21
\item BTU, 331
\item building
\subitem Cambridge University, 298
\subitem data, 141
\subitem energy-efficiency office, 298
\subitem heat consumption, 140, 289
\subitem heat-loss parameter, 294
\subitem Heatkeeper, 297, 299
\subitem leakiness, 294
\subitem Passivhaus, 298
\subitem regulations, 291
\subitem standards, 144
\subitem thermal mass, 305
\subitem typical house, 140
\item bulb, 58
\subitem incandescent, 58
\subitem LED, 58
\subitem low-energy, 58
\item bus, 128
\subitem electric, 120
\item Bush, George W., 42
\item butter, 29, 31
\subitem calorific value, 29
\indexspace
\item C3 plants, 49
\item C4 plants, 49
\item C5, 66, 127
\item cable modem, 68
\item Caithness, 268
\item California, 182
\item calm weather, 186
\item Calorie, 76, 330
\item calorie, 330
\item calorific value, 29, 31, 48, 213, 284
\subitem butter, 29
\subitem coal, 199
\subitem DERV, 199
\subitem diesel, 199
\subitem ethanol, 199
\subitem firewood, 199
\subitem fuel, 29, 199
\subitem gross, 31
\subitem hydrogen, 199
\subitem kerosene, 199
\subitem methanol, 199
\subitem net, 31
\subitem propane, 199
\subitem waste, 287
\subitem wood, 284
\item Caltech, 2
\item Cambridge, 44, 52, 91
\item Cambridge University, 298
\item can, aluminium, 89
\item Canada, 21, 235, 237
\item capacity, 33, 63, 267
\item capacity factor, 33, 267, 268
\item capitalization, 25, 328
\item car, 29, 118, 255
\subitem eco-car, 119
\subitem electric, 127
\subitem embodied energy, 94
\subitem fish, 137
\subitem hybrid, 126
\subitem lights, 57
\subitem manufacture, 94
\subitem recharging, 261
\item carbohydrate, 43
\item carbon capture, 212
\item carbon capture and storage, 157, 240
\item carbon dioxide, 19, 20, 157, 158
\subitem climate change, 5
\subitem data, 6, 9
\subitem equivalent, 11
\subitem greenhouse effect, 5
\item carbon fuel cell, 158
\item carbon intensity, 322
\item carbon monoxide, 158
\item carbon neutralization, 3, 211, 226, 244
\item carbon offset, 3, 226, 244
\item carbon price, 211
\item carbon sequestration, 157, 240
\subitem by cofiring biomass, 211
\subitem cofiring, 212
\item carbon tax, 331
\item carbon-dioxide emissions
\subitem electric car, 131
\item cardboard, 284
\item Cardiff, 84
\item cargo vessel
\subitem nuclear-powered, 133
\item carnivore, 77
\item Cars taken off the road, 330
\item cartoon, 203
\subitem bicycle, 259
\subitem car, 254
\subitem flight, 270
\subitem train, 260
\subitem wind power, 263
\subitem windmill, 264
\item cartoon Britain, 115, 204
\item cartoon of flight, 272
\item cartoon-Britain, 116
\subitem 2008, 116
\item cassette-player, 70
\item cat, 63, 78, 103
\item catamaran, 128, 280, 282
\item cavity-wall insulation, 142, 295
\item CCS, 157, \seealso{carbon capture and storage}{344}
\item cellulosic bioethanol, 205
\item cellulosic ethanol, 284
\item Celsius, 289, 328
\item cement, 325
\item ceramics, 88
\item Cessna, 128, 274
\item CFL, 59
\item Chancellor, 3
\item charger, 68, 69, 72
\item charging, electric vehicle, 197
\item cheese, 76
\item chemical energy, 26, 27, 31
\item chicken, 77
\item chicken feed, 77
\item chicken poo, 42, 286
\item chimney, 145, 157
\subitem solar, 182
\item China, 5, 21, 321
\item CHP, \see{combined heat and power}{344}
\item circulation of oceans, 242
\item Citro\"en Berlingo, 127
\item civilization, 50
\item Clarkson, Jeremy, 126
\item clay, 325
\item clean coal, 203, 212
\item cliff, 11
\item climate change, 5, 10
\subitem greater threat than terrorism, 4
\subitem is about energy, 5
\item climate modelling, 11
\item climate-change inactivists, 8, 240
\item clock-radio, 70
\item clothes dryer, 51
\item clothes washing, 50, 51
\item cloud cover, 38
\item cloudy day, 45
\item clutter, 88
\item CO$_2$, \see{carbon dioxide}{344}
\item coal, 8, 94, 158, 206, 284
\subitem British resource, 6
\subitem calorific value, 199
\subitem clean, 203, 212
\subitem contains uranium and thorium, 175
\subitem energy density, 199
\subitem nuclear radiation from, 168
\subitem power station closures, 342
\subitem UK, 158
\item coal imports, 343
\item coal mines, 208
\item coal mining, 158, 161
\item coal power station, 5, 157, 330
\item coal production, 6, 343
\item coal substitution, 42
\item coalition of the willing, 244
\item coastline, 65, 74
\item coefficient of performance, 147, 153, 154, 292, 300
\item coffee, 332
\item cofiring biomass, 211
\item cogeneration, 145
\item coke, 89, 94
\item Colorado, 286
\item combined heat and power, 144--147
\subitem arguments against, 146
\subitem data, 149
\item combustion, 31
\item commuting, data, 30, 127, 136
\item compact fluorescent light, 59
\item compact linear fresnel reflector, 184
\item computer, 68, 69, 89
\subitem manufacture, 94
\item concentrating solar power, 40, 178, 184
\subitem parabolic trough, 178
\item concentrator photovoltaics, 182
\item concrete, 325
\item condensation, 296
\item condensing boiler, 148, 151, 292
\item conductivity, 303
\item confusion
\subitem power and efficiency, 47
\subitem power and energy, 24
\item congestion, 124
\item congestion charging, 135
\item conservation of energy, 26
\item Conservative Party, 114
\item consumption, 22
\subitem European, 104
\item container, 91, 332
\item container ship, 91
\item continent, 97
\item continental Europe, 145, 329
\item continental shelf, 82, 243
\item contraction and convergence, 15
\item convective heat loss rate, 290
\item conversion losses, 104
\item conversion table, speed, 263
\item conveyor belt, ocean, 242
\item cooker, 50, 51
\item cooking, 50, 207
\item cooling, 147
\item cooling tower, 145
\item CoP, 147
\item copper, 325
\item cordless phone, 69
\item Coriolis force, 82
\item corn, 286
\item cornish pasties, 91
\item Cornwall, 91
\item Coronation Street, 196
\item cost, 211, 214
\subitem arms, 221
\subitem nuclear decommissioning, 175
\subitem offshore wind, 66
\subitem wind, 66
\item counter-current heat exchange, 296
\item countries, 17, 105, 231, 336, 337
\subitem civilized, 50
\item countryside, 208
\item cow, 76, 77, 79
\item CPV, \see{concentrator photovoltaics}{344}
\item crisps, 80
\item crock of manure, 8
\item Croesor, 202
\item crops, 286
\item CRT (cathode ray tube), 70
\item Cruachan, 191
\item crude oil, 19, 206
\subitem production, 5
\item cruise-ship, 88
\item crust, 96
\item CSP, \see{concentrating solar power}{344}
\item cubic foot, 334
\item cubic metre, 334
\item cup, 332
\item cup of tea, 331
\item current, 84
\item Curtis, Jamie Lee, 130
\item CUTE, 130
\item cv, 333
\item cyclist, 264
\item Czech Republic, 21
\indexspace
\item dairy, 76, 79
\item dam, 55
\item damp, 296
\item Darth Vader, 68
\item data
\subitem area, 338
\subitem bathymetry, 61
\subitem calorific values, 284
\subitem carbon intensity of electricity production, 335
\subitem carbon intensity of fuels, 335
\subitem CO$_2$ concentrations, 6, 9
\subitem coal imports, 343
\subitem coal production, 6, 7, 9, 343
\subitem combined heat and power, 149
\subitem commuting, 30, 127, 136
\subitem countries, 338
\subitem depths, 61
\subitem electric car, 127
\subitem electrical generation capacity, 342
\subitem electricity demand, 342
\subitem electricity production, 342, 343
\subitem emissions, 15
\subitem emissions of cars, 136
\subitem energy consumption, 105, 231, 337
\subitem energy gap, 342
\subitem fossil fuels, 343
\subitem freight, 92
\subitem G-Wiz, 127
\subitem gas consumption, 343
\subitem gas demand, 200
\subitem GDP, 105, 231, 336
\subitem greenhouse gas emissions, 9, 14, 336, 337
\subsubitem by country, 13
\subsubitem by region, 12
\subsubitem historical, 14
\subitem heat consumption, 141
\subitem heat pump, 150
\subitem height, 55
\subitem hydroelectricity, 343
\subitem Iceland, 97
\subitem imports, 323
\subitem incineration, 207
\subitem landfill, 207
\subitem nuclear power, 343
\subitem nuclear power by country, 161
\subitem offshore wind, 64
\subitem oil consumption, 284
\subitem oil price, 5
\subitem oil production, 5--7, 9
\subitem photovoltaics, 40
\subitem population, 9, 338
\subitem power station closures, 5
\subitem pumped storage, 201
\subitem recycling, 207
\subitem rolling resistance, 258
\subitem sea depths, 61
\subitem straw production, 286
\subitem sunniness, 38, 44, 238
\subitem urban population density, 152
\subitem waste, 207
\subitem water depths, 61
\subitem wind
\subsubitem Cairngorm, 32
\subsubitem Cambridge, 32, 34
\subsubitem Ireland, 187
\subitem wind power fluctuations, 188
\subitem wood, 284
\item DD, 172
\item decentralization, 146
\subitem micro-turbines, 63
\item decommissioning, 217
\item deep offshore wind, 60, 66
\item definition
\subitem sustainable, 157
\item degree-day, 291, 293
\item Delaware, University of, 47
\item deliberate inaccuracy, 16
\item delivery vehicle, electric, 138
\item demand
\subitem electricity, 186, 188, 342
\subitem gas, 200
\item demand management, 189, 196, 197
\item Denmark, 26, 33, 34, 63, 197
\item density, 31, 263
\item Department of Defense, 102
\item depths, 61
\item DERV
\subitem calorific value, 199
\subitem energy density, 199
\item desalination, 92, 93, 310
\item desert, 178
\item deuterium fusion, 172
\item Diamond, Jared, 177
\item diesel, 31
\subitem calorific value, 199
\subitem energy density, 199
\item digital hydraulics, 126
\item digital radio, 70
\item Dinorwig, 191--193, 216, 329
\item direct carbon fuel cell, 158
\item direct normal irradiance, 180
\item dirigible, 280
\item dishwashing, 50, 51
\item district heating, 145
\item diversity, 207
\item DIY planet repairs, 72, 154
\item do your bit, 3
\item dog, 78
\item door, 294
\item double decker bus, 332
\item double glazing, 141, 294
\item double-decker bus, 3
\item double-effect generation, 311
\item Dounreay, 163
\item drag, 118
\item drag coefficient, 137, 254--256
\item drag-to-lift ratio, 273
\item draught proofing, 141, 289
\item Drax, 330
\item drinks can, 89
\item driving, 79
\item DT, 172
\item duck, Salter, 309
\item DVD player, 69
\item Dynamic Demand, 202
\item dynamic demand, 196
\indexspace
\item e, 333
\item e500, 137
\item eagle, 63
\item earth, 10, 81, 325
\subitem area, 332
\item easily turn-off-and-onable, 186
\item EastEnders, 196
\item Eco Cute, 154
\item eco-boat, 128, 130
\item Eco-Bollocks award, 66
\item eco-car, 119
\item economic costs, 23
\item economics, 66, 203, 211
\subitem of wind, 34
\item economies of scale, 34
\item economist, 2
\item economy, 29
\item EdF, 5, 342
\item EEStor, 199
\item efficiency, 115, 191, 201
\subitem confused with power, 47
\subitem improvements, 42
\subitem more-efficient planes, 37
\subitem of incineration, 44
\subitem of plants, 49
\subitem of solar panels, 47
\subitem scope for improvement, 23
\item efficiency legislation, 153
\item Eggborough, 330
\item EGS (enhanced geothermal systems), 234
\item Einstein, 277
\item Eisenhower, D.D., 100, 133
\item ekranoplan, 281
\item Elean Power Station, 288
\item Electra, 278
\item electric bus, 120
\item electric car, 128
\subitem CO$_2$ emissions, 131
\subitem data, 127
\subitem range, 261
\subitem recharging, 261
\subitem theory, 261
\item electric fan heater, 51
\item electric vehicle, 197, 206
\subitem battery cost, 131
\subitem in cold places, 132
\subitem in hot places, 131
\subitem lifetime, 131
\subitem RAV4, 138
\item electric vehicles, 189
\item electric vehicles and wind power, 195
\item electrical energy, 27
\item electricity, 50, 69, 203
\subitem demand management, 196
\subitem demand varies, 186
\subitem greening of, 131
\subitem grid, 197
\subitem hydroelectric, 55
\subitem mains, 196
\subitem supply, 50, 131, 204, 342
\subsubitem energy gap, 5
\item electricity production, 343
\item electrification
\subitem of heating, 205
\subitem of transport, 204
\item Elettrica, 127
\item embedded, 89
\item embodied, 89
\item embodied energy
\subitem aluminium, 94
\subitem building, 326
\subitem building materials, 325
\subitem car, 94, 324
\subitem glass, 325
\subitem metal, 325
\subitem paper, 95
\subitem PET, 94
\subitem rock, 325
\subitem steel, 94
\subitem water, 95
\subitem wood, 325
\item emissions
\subitem flight, 16
\subitem flying, 16
\subitem of electricity production, 335
\subitem of fuels, 335
\subitem travel, 16
\item emissions trading, 217, 226
\item enemy of the people, 4
\item energy, 24
\subitem chemical, 31
\subitem conservation, 26
\subitem contrasted with power, 24
\subitem geothermal, 96
\subitem kinetic, 28
\subitem low-grade, 39
\subitem of vaporization, 31
\subitem spending, 217
\subitem wave, 307
\item energy amplifier, 166
\item energy conversion, 103
\item energy crops, 42, 283
\item energy demand variations, 186, 200
\item energy density, 29, 31, 284
\subitem butter, 29
\subitem coal, 199
\subitem DERV, 199
\subitem diesel, 199
\subitem ethanol, 199
\subitem firewood, 199
\subitem fuel, 29, 199
\subitem hydrogen, 199
\subitem kerosene, 199
\subitem lead-acid battery, 199
\subitem lithium-ion battery, 199
\subitem methanol, 199
\subitem propane, 199
\item energy efficiency, 58
\item energy gap, 5, 342
\item energy intensity, 115
\item energy waste league, 68
\item energy yield ratio, 41, 42
\subitem solar PV, 41
\subitem wind, 42
\item engineer, 31
\item England, rainfall, 55
\item England--France interconnector, 183, 209
\item enhanced geothermal extraction, 98
\item entertainment system, 69
\item entropy, 26, 92
\item environmental costs of renewables, 23
\item equator, 38
\item estimation, 264
\item Estonia, 21
\item ethanol, 42
\subitem calorific value, 199
\subitem energy density, 199
\subitem from corn, 284
\subitem from sugar cane, 284
\item Etheridge, D. M., 19
\item ethical assertions, 18
\item ethics, 11
\subitem breeder reactor, 163
\subitem pollution, 14
\item Europe, 43, 104, 108, 207, 233, 338
\subitem continental, 145, 146, 329
\item European Union, 219
\item European Wind Energy Association, 235
\item EV1, 137
\item Evans, R.\ Keith, 139
\item every little helps, 3, 58, 68
\item evil, 68
\item exchange rate, 27
\item Exxon, 219
\indexspace
\item factory, 88
\item factual assertions, 17
\item Fair Isle, 197, 198
\item fallacy, \seealso{myth}{344}
\subitem Limits to Growth, 174
\item farm
\subitem solar, 208
\item fast breeder reactor, 162, 163
\item fat is 6000 metres per second, 277
\item faucet, 24
\item fertilizer, 43, 48, 78, 80
\item fetch, 73
\item Fetish, 138
\item FEU, 332
\item Ffestiniog, 191
\item fibreglass, 325
\item Fido, 78
\item filling station
\subitem role in electric transport, 261
\item finesse, 273
\item finger millet, 49
\item Finland, 208, 216
\item fire
\subitem electric, 51
\item fire, electric, 51
\item firewood
\subitem calorific value, 199
\subitem energy density, 199
\item Fischer, Joschka, 177
\item fish, 137
\item flight
\subitem boats that fly, 279
\subitem emissions, 16, 36
\subitem formation, 270
\subitem future of, 132, 211
\subitem myth about going slower, 269
\subitem optimal speed, 272
\subitem optimum height, 277
\item flight record, 277
\item Flor{\o }, 312
\item flow, 24, 84
\item fluctuations, 186, 205, 210
\item fluff, 141
\item fluorescent bulb, 58
\item flux, sunlight, 38
\item flywheel, 198
\item fog, 11
\item food, 38
\subitem waste, 43, 219
\item food miles, 91
\item food waste, 48
\item football, 197
\item foreigners, 5
\item forest, 205, 235
\item formation flying, 270, 278
\item formula
\subitem kinetic energy, 30
\subitem wave, 307
\item Formula One, 333
\item Fossett, Steve, 277
\item fossil fuel, 203
\subitem backup for wind, 187
\item fossil fuels, 5
\subitem peaking of, 5
\item Foyers, 191
\item fractal, 65
\item France, 21, 171, 208, 209, 211
\item freezer, 50
\item freight, 133, 324
\subitem energy consumption, 92
\item fridge, manufacture, 94
\item fridge-freezer, 50, 69
\item Friends of the Earth, 19
\item frontal area, 119, 255
\item fuel
\subitem calorific value, 29, 199
\subitem energy density, 29, 199
\item fuel cell
\subitem bus, 130
\subitem direct carbon, 158
\item fuel efficiency, plane, 36
\item Fujitsu, 147
\item fusion reactor, 172
\indexspace
\item $g$, 307
\item G-Wiz, 127
\subitem data, 127
\item gadget, 69
\item Gaia, 2
\item gallium arsenide, 40
\item gallon, 331
\item galvanised steel, 325
\item garden, 147
\item gas, 206
\subitem landfill, 287
\subitem methane, 287
\subitem national demand, 200
\item gas consumption, 343
\item gas mantle, 166
\item gas meter, 334
\item gas pipeline, 62
\item gas power station, 148
\item gasoline, 31
\item GDP, 105, 231, 336
\item geese, 278
\item General Motors, 129, 137
\item genetic engineering, 44
\item genetic modification, 43, 49, 286, 288
\item geoengineering, 240
\item geothermal, 96, 147, 237
\subitem enhanced, 98
\subitem hot dry rock, 99
\subitem Iceland, 183
\subitem magma, 99
\item geothermal energy, 96
\item geothermal mining, 96
\item geothermal power, 26, 96
\item Germany, 21, 33, 34
\item get building, 250
\item GHG, \see{greenhouse gas}{344}
\item giant vacuum cleaner, 244
\item gigaton, 240
\item gigawatt, 25, 188
\item gigawatt-hour, 25
\item giggle, 25
\item Giza, 332
\item Glasgow, 33, 56
\item glass, 88, 325
\item glasswool, 325
\item glazing, 294
\item glazing, double, 141
\item Glendoe, 56
\item glide number, 273
\item glide ratio, 273
\item global warming, 10
\item GlobalFlyer, 277
\item glorification of travel, 4
\item GM, 129
\item GM EV1, 137
\item gmt, 252
\item gnuplot, 252
\item godwit, 277
\item good-against-evil, 100
\item goods, 88
\item Goodstein, David, 2
\item Google, 239
\item gown, 293
\item grain crops, 286
\item granite, 301, 302, 325
\item grass, 42
\item gravity, 307
\item grazing, 78
\item Great Yarmouth, 268
\item green algae, 286, 288
\item Green Party, 210
\item greenhouse effect, 5, 10
\item greenhouse gas, 10
\item greenhouse gas emissions, 5, 8, 9, 11, 15
\subitem by country, 13
\subitem by region, 12
\subitem historical, 14
\subitem natural, 8
\item greening electricity supply, 131
\item Greenland icecap, 10
\item Greenpeace, 4, 19, 161, 210, 235, 269
\item Gretar \'Ivarsson, 97
\item gross calorific value, 31
\item ground-source heat pump, 147, 152, 205
\item Grubb, Michael, 226
\item guerrilla physics, 31
\item GW, 25
\item GW(e), 333
\item GWp, 333
\item gypsum, 325
\indexspace
\item hair-dryer, 88
\item Haishan, 321
\item Hammerfest, 84
\item Hansen, Jim, 248
\item hardboard, 325
\item hardwood, 284, 325
\item hate, 4
\item Hawaii, 6
\item heat, 10
\subitem waste, 145
\item heat capacity, 50, 302
\item heat engine, 145
\item heat exchanger, 297
\item heat flow, 97
\item heat loss parameter, 297
\item heat pump, 26, 52, 146, 205, 300, 301
\subitem air source, 151
\subitem air-source, 147
\subitem ground-source, 147, 152
\subitem winter, 153
\item heat-loss coefficient, 140, 141, 291
\item heat-loss parameter, 294, 295
\item Heathrow Airport, 217
\item heating, 203
\subitem efficiency, 292
\subitem under-floor, 151
\item Heatkeeper, 297, 299
\item Heaton, Emily, 43
\item hectare, 246
\item height, of flight, 277
\item heights, 55
\item helicopter, 128
\item Heliodynamics, 40, 48
\item heliostats, 184
\item helium, 280
\item Helm, Dieter, 322
\item Helston, 91
\item Herne Bay, 60
\item HEU, 102
\item high heat value, 31
\item high-enriched uranium, 102
\item highland hydroelectricity, 56
\item highlands, 55
\subitem rainfall, 55
\item history, 108
\item hockey stick graph, 19
\item home, 4, 329
\item Honda, 31, 139
\subitem FCX Clarity, 130
\subitem fuel-cell car, 130
\item hoop, 263
\item Horns Reef, 61, 65
\item horse, 78
\item horsepower, 28
\item hot air, 51
\item hot dry rock, 98, 99
\item hot water, 26, 50
\item hours of sunshine, 44
\item house, 293
\item House of Lords, 228
\item Housebuilder's Bible, 66
\item household waste incineration, 43
\item hp, 333
\item Hummer, 129, 130
\item HVDC, 178, \see{high voltage DC}{344}
\item hybrid cars, 126
\subitem compared, 126
\subitem misleading advertising, 126
\item hydraulics, digital, 126
\item hydrocarbon, 29, 31
\item hydroelectricity, 55, 206, 235
\subitem highland, 56
\subitem Iceland, 183
\item hydroelectricity production, 343
\item hydrofoil, 279
\item hydrogen, 130, 286
\subitem and boron, 202
\subitem and wind power, 195
\subitem calorific value, 199
\subitem energy cost of, 139
\subitem energy density, 199
\subitem from algae, 285
\subitem from bacteria, 42
\subitem plane, 277
\subitem production by nuclear power, 174
\subitem storage efficiency, 196
\item hydrogen car, 128, 130, 139
\item hydrogen vehicles, 195
\item hype, 146
\item HyperCar, 139
\indexspace
\item i MiEV, 137
\item ice cores, 6
\item ice-breaker, 133
\item Iceland, 96, 97, 183, 185, 197
\item IKEA, 155
\item imported power, 206
\item imports, 322
\subitem coal, 343
\subitem energy, 209, 211
\item imprecision, deliberate, 16
\item inaccuracy, deliberate, 16
\item inactivist, 8
\item incineration
\subitem efficiency, 44
\subitem waste, 43
\item Independent, 8, 20, 66
\item Indermuhle, A., 19
\item India, 21, 166, 237
\item Industrial Revolution, 6, 9
\item information systems, 68
\item infrared, 10
\item insulation, 141, 205, 296
\item insurance, 217
\item interconnector
\subitem England--France, 179, 183
\subitem Iceland, 183
\subitem Norway, 197, 207
\item intercontinental flight
\subitem emissions, 16
\item intermittency, 62
\item internet, 21
\item investment, 217
\item IPCC, 36, 169, 249
\item Iraq war, 221
\item Ireland, 73, 187, 201, 312
\subitem wind output, 187
\item irresponsible journalism, 8
\item irrigation, 43
\item Isaac Asimov, 115
\item island
\subitem nuclear, 174
\item Islay, 75
\item Isles of Scilly, 83
\item ITER, 172
\indexspace
\item J-Power, 194
\item jack-up barge, 63, 67, 208, 216
\item Japan, 21, 144, 151, 173, 268, 338
\subitem efficiency legislation, 153
\item jatropha, 284
\item Jersey, 310
\item Jersey Police, 138
\item Jersey Water, 93
\item JET, 198
\item jet fuel, 31
\item jet travel, 211
\subitem emissions, 16
\item jet-ski, 128, 130
\item Jevons, William Stanley, 20, 157, 158, 186
\item joule, 25, 328
\item journalism, bad, 8
\item journalist, 139
\item jumbo jet, 273, \see{747}{344}
\item junk mail, 4
\item Jutland, 65
\indexspace
\item Kazakhstan, 177, 338
\item kcal, 76, 330
\item Keeling, C. D., 19
\item keeping the lights on, 68
\item kelvin, 289
\item Kemp, Roger, 135
\item Ken, 72, 154
\item Kentish Flats, 60, 64, 67, 216
\item kerosene
\subitem calorific value, 199
\subitem energy density, 199
\item kettle, 50, 51, 197
\item Khrushchev, 281
\item kilocalorie, 330
\item kiloton, 101
\item kilowatt, 50
\item kilowatt-hour, 24
\item kilowatt-hour per day, 24
\item kinetic energy, 28, 255, 263, 307
\item kinetic-energy storage, 198
\item king coal, 8
\item King, David, 228, 248
\item Kinlochewe, 55, 56
\item knot, 84
\item kW(e), 333
\item kWp, 333
\indexspace
\item $\lambda$, 307
\item La Rance, 84, 85
\item Labour, 19
\item laminar flow control, 275
\item laminated wood, 325
\item landfill, 43, 88, 206, 207
\item landfill gas, 287
\item landlord, 227
\item Langeled, 62, 63, 219
\item laptop computer, 70
\item Larry, 227
\item laser-printer, 69, 70
\item last thing, 240
\item laundry, 50, 51
\item laws of physics
\subitem conservation of energy, 26
\item Lawson, Dominic, 8, 20
\item layer (chicken), 77
\item LCA, \see{lifecycle analysis}{344}
\item LCD (liquid crystal display), 70
\item lead-acid battery
\subitem efficiency, 202
\subitem energy density, 199
\item leadership, 230
\item leakiness, 141, 291, 293, 294
\item Learjet, 128, 275
\item LED, 58, 205
\item Leggett, Jeremy, 228
\item lego, 88
\item LEU, 102
\item Lexus, 126
\subitem misleading advertising, 126
\item Liberal Democrats, 210, 213
\item Libya, 177, 338
\item life-cycle
\subitem of stuff, 88
\item life-cycle analysis, 88, 131
\item lifecycle analysis, 324
\item lifestyle change, 141
\item lift-to-drag ratio, 273, 278
\item lightbulb, 58
\subitem incandescent, 58
\subitem LED, 58
\subitem low-energy, 58
\item Lightning car, 137
\item lights, on cars, 57
\item Limits to Growth, 174
\item Limpet, 75
\item liquid fuels
\subitem from plants, 283
\item liquid salt
\subitem energy storage, 178
\item litany, 10, 21
\item lithium, 139, 172, 176
\item lithium fusion, 172
\item lithium titanate, 137
\item lithium-ion, 137
\item lithium-ion battery
\subitem efficiency, 202
\subitem energy density, 199
\item lithium-ion polymer battery
\subitem energy density, 199
\item lithium-sulphur, 202
\item litre, 332
\item little square, 236
\item Livingstone, Ken, 154
\item Llyn Stwlan, 191
\item load factor, 33, 64, 66, 267, 268
\item Loch Lomond, 192, 193
\item Loch Sloy, 56, 193
\item loft insulation, 141
\item logarithmic scale, 7, 9
\item Lomborg, Bj{\o}rn, 2
\item London, 72, 154, 206, 217
\item London Array, 66
\item London Underground, 135
\item long-distance electricity transmission, 112
\item Loremo, 137
\item Los Angeles, 3
\item love, 4
\item Lovelock, James, 2
\item low heat value, 31
\item low-enriched uranium, 102
\item low-grade energy, 39
\item low-grade heat, 97
\item lowlands, 55
\subitem rainfall, 55
\item LPG, 94
\item lumber, 325
\item lumens per watt, 58
\item Lun, 281
\item lunar energy, 82
\item Luxembourg, 21
\indexspace
\item m, 329
\item magic playing field, 4, 171
\item magma, 99
\item magnesium silicate, 246
\item Magnus platform, 63
\item mains electricity, 196
\item maize, 49
\item make-up, 219
\item Malin Head, 312
\item manufacture, 94
\item manufacturing, 68, 131
\item manure, 8
\item Manzanares, 183
\item map, 11
\item Maplin, 68
\item Marchetti, C., 174
\item margarine, 29
\item Mastrandrea, Michael, 15
\item Mayor of London, 72, 154
\item Mazda, 131
\item McCarthy, Donnachadh, 66
\item McMahon, Richard, 72
\item McNuggets, 42
\item MDF, 325
\item meat, 77
\item meat-eating, argument for, 78
\item Mega City, 137
\item megaton, 101
\item membrane, 92
\item mercury, 58
\item metal, 88
\item metapost, 252
\item meter reading, 334
\item methane, 43, 206, 287
\item methane hydrates, 243
\item methane pollution, 158
\item methanol, 209
\subitem calorific value, 199
\subitem energy density, 199
\item metre, 328
\item Mexican wave, 307
\item Mexico, 235
\item micro-CHP, 145
\item micro-generation, 63, 268
\item micro-turbine, 63, 268
\item micro-wind, 63
\item microwave, 50, 51
\item Middle Ages, 108
\item middlehen, 78
\item middlesow, 78
\item migration, 278
\item military, 221
\subitem aid, 221
\item milk, 76
\item milliard, 329
\item million, 329
\item millpond, 74
\item mine, 186
\item mini-SUV, 138
\item mini-turbine, 268
\item mining
\subitem coal, 158, 161
\subitem geothermal, 96
\item Mio, 329
\item mirror, 40
\item miscanthus, 43, 48, 205, 283
\item misleading advertising, 126
\item misleading presentation, 171
\item MIT, 98, 99
\item mixing, 92
\item mobile-phone charger, 68, 72
\item Modec, 138
\item modem, 68
\item molten salt, 178
\item monazite, 166
\item moon, 81, 82, 96
\item Moore, Patrick, 161
\item mortar board, 293
\item motivations, 5
\item motorcycle, 11
\item motorway, 217
\item Mrd, 329
\item Mt, 329
\item Mtoe, 329
\item M\"uhlhausen, 41, 48
\item multinational chemicals, 89
\item multiple-junction photovoltaics, 47
\item municipal solid waste, 207, 284
\item mutton, 78
\item MW(e), 333
\item MWp, 333
\item MyCar, 137
\item myth
\subitem car inefficiency, 119
\subitem carbon trading, 226
\subitem food, 79
\subitem hydroelectricity, 56
\subitem new planes far more efficient, 132
\subitem nuclear power build rate, 171
\subitem offsetting, 3, 226
\subitem planes should fly slower, 269
\subitem solar panels, 45
\subitem walking, 79
\subitem wind reliability, 201
\indexspace
\item Nanosafe, 137
\item Nant-y-Moch, 55
\item National Academy of Sciences, 20
\item national gas demand, 200
\item National Renewable Energy Laboratory, 286
\item natural gas, 206, 287
\subitem demand varies, 200
\subitem leaks, 158
\subitem national demand, 200
\item Nature magazine, 129, 139
\item Nazi invasion, 110, 112, 267
\item neap tide, 81, 84
\item Neftel, A., 19
\item net calorific value, 31
\item Netherlands, 201
\item neutralization, carbon, 3, 226, 244
\item New Jersey, 236
\item New Mexico, 182
\item New Scientist, 4, 19
\item New Zealand, 264
\item Newbery, David, 226
\item newspaper, 94, 95, 284, 287
\item newsprint, 95
\item newton, 259, 328
\item Newton's laws, 269
\item nickel cadmium battery
\subitem energy density, 199
\item nickel metal hydride battery
\subitem energy density, 199
\item nickel-cadmium, 89, 94
\item NIMBY, 208
\item nitrogen, 272
\item nitrous oxides, 36
\item nomenclature, 328
\item North America, 234
\item North Hoyle, 64, 268
\item North Sea, 73, 82, 83
\subitem oil, 5
\item Northern Ireland, 85
\item Norway, 63, 84, 136, 190, 197, 219, 312
\item nose, 296
\item nostril, 296
\item NS Savannah, 133
\item nuclear, 211
\subitem capacity, 342
\subitem hydrogen production, 174
\subitem power station closures, 5, 342
\subitem reactor
\subsubitem breeder, 163
\subsubitem energy amplifier, 166
\subsubitem fusion, 172
\subsubitem once-through, 162
\subitem weapon, 100, 161
\subsubitem testing, 220
\item nuclear clean-up costs, 175
\item nuclear decommissioning authority, 167, 175
\item nuclear power, 2, 4, 19, 68, 206
\subitem costs, 165, 167
\subitem data by country, 161
\subitem decommissioning, 165, 217
\subitem inflexibility, 186
\subitem station, 162
\subsubitem build rate, 171
\subsubitem construction, 169
\subsubitem fuel required, 165
\item nuclear radiation
\subitem from coal power, 168
\item nuclear reactor
\subitem fast breeder, 163
\item nuclear stockpile, 220
\item numbers, 4
\indexspace
\item O'Leary, Michael, 36
\item oats, 286
\item ocean, 81
\subitem uranium extraction, 165
\item ocean circulation, 242
\item ocean conveyor belt, 162, 242
\item ocean liner, 128, 133
\item Ocean Power Delivery, 309
\item offsetting, 3, 226, 244
\item offshore wind, 60, 64
\subitem cost, 66
\subitem data, 64
\subitem deep, 60
\subitem jack-up barges, 63, 208, 216
\subitem load factor, 268
\subitem shallow, 60
\item oil, 206
\subitem North Sea, 5
\subitem price, 5
\item oil consumption, world, 284
\item oil field, 64
\item oil platform, 64
\item oil power stations, 5
\item oilrig, 60
\item oilseed rape, 283
\item oilspinner, 10
\item Okinawa, 194
\item olivine, 246
\item Olkiluoto, 216
\item on-site renewables, 300
\item once-through, 162
\item orange, 96
\item Orkney, 82, 268
\item Otto cycle, 136
\item Out of Gas, 2
\item outlet, 50
\item oven, 50, 51
\item overcast day, 45
\item oxygen, 272
\item Oxygen Cargo, 138
\item Oyster, 310
\item ozone, 36
\indexspace
\item p, 333
\item p-km, 118
\item packaging, 88
\item paddling pool, 82
\item paint, 325
\item paper, 3, 89, 95, 284, 322
\subitem embodied energy, 95
\item parabolic trough, 178
\item particleboard, 325
\item passenger-kilometre, 118
\item Passivhaus, 298
\item pasties, 91
\item patio heater, 52
\item peak, 267
\item peak nuclear, 2
\item peak oil, 2, 5, 20
\item peak power, 63
\item pedant, 31, 65
\item pee, 92
\item Pelamis, 74, 208, 309
\item perfume, 219
\item period, 307
\item PET
\subitem embodied energy, 94
\item petagram, 329
\item petrol, 31
\item petrol engine, 136
\item petrol pump, 333
\item petroleum substitution, 42
\item Pg, 329
\item Phoenix SUT, 138
\item phone, 68
\item phone charger, 4, 68
\item photosynthesis, 43, 286
\subitem efficiency, 49
\item photovoltaic, 38, 39
\item photovoltaic panels, 45
\item physicist, 2
\item physics, 30
\subitem conservation of energy, 26
\subitem Newton's laws, 269
\item pick-ups, 196
\item pig, 77
\item pig-iron, 9
\item pilot, 277
\item pint, 331, 332
\item pipeline, 219
\item plan, 163
\item plan D, 207
\item plan E, 211
\item plan G, 210
\item plan L, 209
\item plan M, 214, 216
\item plan N, 208
\item plane, 35
\subitem efficiency improvements, 37
\subitem myth about flying slower, 269
\subitem turboprop, 35
\item planes
\subitem boats as an example of, 279
\item planet, 10
\subitem destruction, 68
\item planet Dorkon, 29
\item plant yields, 48, 283
\item plants
\subitem C3, 49
\subitem C4, 49
\subitem more efficient, 49
\item plaster, 325
\item plasterboard, 325
\item plastic, 88, 325
\item plutonium, 101, 102
\item plywood, 325
\item politics, 203
\item polluter pays, 14
\item pollution, 58
\item pool, 82
\item poplar, 205, 283
\item poppycock, 171
\item population density, 33, 177, 213
\subitem urban, 152
\item population growth, 7, 9, 115
\item population reduction, 4, 115
\item pork, 77
\item Porritt, Jonathan, 2
\item positive feedback, 243
\item potential energy, 307
\item power, 24
\subitem confused with efficiency, 47
\subitem definition, 24
\subitem of sunshine, 38
\subitem standby, 155
\item power density, 41
\subitem all renewables, 112, 177
\subitem biofuel, 283
\subitem concentrating solar power, 178, 184
\subitem highland hydroelectricity, 56
\subitem hot water panels, 39
\subitem hydroelectricity, 55, 56
\subitem miscanthus, 43
\subitem offshore wind, 60
\subitem photovoltaics, 47
\subitem plants, 43
\subitem rape, 283
\subitem sunshine, 38
\subitem wind, 263
\subitem wind farm, 32
\item power meter, 68
\item power per unit area, \see{power density}{344}
\item power per unit length
\subitem tide, 83, 312
\subitem wave, 74
\item power station, 5, 26, 103, 330, 342
\subitem closures, 5
\subitem coal, 330
\item Powergen, 342
\item ppm, 248
\item presentation, misleading, 4, 171
\item President Dwight D.\ Eisenhower, 100, 133
\item Prestatyn, 64
\item printer, 70
\item Prius, 126, 136
\item Process Energy Requirement, 324
\item projector, 70
\item pronunciation, 25
\item propane
\subitem calorific value, 199
\subitem energy density, 199
\item ps, 333
\item PS10, 184
\item public negativity, 250
\item public transport, 204
\item pumped storage, 86, 189, 191, 192, 210
\subitem efficiency, 191, 201
\item Punch and Judy show, 250
\item PVC, 325
\item pyramid, 332
\indexspace
\item Qatar, 21
\item QE2, 128
\item quad, 331
\item quart, 331
\item quartz, 302
\item Queen's University Belfast, 310
\item quilt, 10
\indexspace
\item radiator, 51
\item radio, 70
\item radioactive decay, 96
\item rail, 119, 258--260
\subitem energy consumption, 92
\subitem freight, 92
\item rainfall, 55
\item Rance, 85
\item ranch, 42
\item range
\subitem electric car, 261
\subitem of bird, 276
\item Range Rover, 128
\item rape biodiesel, 283
\item Rapley, Chris, 115
\item Rau, Nick, 19
\item RAV4, 138
\item reactive power, 72
\item reactor, 167
\subitem fast breeder, 163
\item rechargeable battery, 89, 94
\item recharging, 261
\item record, flight, 277
\item recycling, 88, 206
\subitem data, 207
\item refrigeration, 26
\item refrigerator, 50, 146, 147
\subitem manufacture, 94
\item refrigerators
\subitem and demand management, 196
\item regenerative braking, 125
\item religion, 197
\item renewable energy
\subitem research and development, 221
\item renewable obligation certificate, 66
\item renewables, intermittency, 186
\item reporters, 68
\item research and development, 221
\item REVA, 127
\item reverse osmosis, 92, 93, 196, 310
\item Rijndam, 133
\item river, 145
\subitem uranium, 165
\item River Deben, 82
\item road freight, 91
\item roadmap, 203
\item ROC, \see{renewables obligation certificate}{344}
\item rock, 96
\item Rocky Mountain Institute, 139
\item rolling resistance, 258
\item Rolls Royce, 37
\item Rosemanowes, 98
\item rotor, 267
\item Royal Albert Hall, 332
\item rubber, 258, 325
\item Rubbia, Carlo, 166
\item rubbish, 88
\item runaway feedbacks, 243
\item Russia, 21, 133, 237
\item Ryanair, 36
\indexspace
\item Sahara, 178
\item Saint-Malo, 85
\item salinity, 242
\item salt water, 92
\item salt, heat storage, 178
\item Salter, Stephen, 135
\subitem duck, 309
\item San Francisco, 120
\item Sandia National Laboratories, 99
\item Saudi Arabia, 6, 177, 220, 338
\item Saudi oil, 9
\item sausage, 270, 272
\item Sauven, John, 19
\item Savannah, 133
\item SAX-40, 37
\item saying no, 108
\item Scaled Composites, 277
\item sceptic, 6, 8
\item Schwarzenegger, Arnold, 130
\item Scotland, 64, 83, 192, 198
\subitem rainfall, 56
\item screen, 69
\item Scroby Sands, 268
\item sea depths, 61
\item sea snake, 309
\item sea-level rise, 10, 17
\item SeaBus, 120
\item seawater, 93, 162, 166, 172, 174, 176
\subitem uranium extraction, 165, 174
\item second, 328
\item security of energy supply, 5, 111
\subitem wind, 187
\item SELCHP, 216, 287
\item separative work unit, 102
\item sequestration, 157, 240
\item servant, 24
\item set-top box, 68
\item Severn barrage, 85
\item Severn Estuary, 84
\item Seville, 184
\item sexy personalities, 205
\item Shadowfax, 78
\item shallow offshore wind, 60
\item shallow water, 310
\item sheep, 78
\item Shell, 66, 219
\item Shell UK, 60
\item Shetland, 268
\item ship, 9
\subitem container, 91
\subitem cruise-ship, 88
\subitem energy consumption, 92
\subitem nuclear-powered, 133
\subitem painting, 3
\item shipping, 91, 95, 133
\item Shockley--Queisser limit, 47
\item shop, 88
\item short-rotation coppices, 49
\item shower, 50, 51
\item SI, 328
\item Siberia, 243
\item Siegenthaler, Urs, 19
\item silent aircraft, 37
\item simplification, 16
\item Sinclair C5, 66, 127
\item Sizewell, 167
\item sleep, 69
\item slew rate, 188
\item slime, 285
\item small is beautiful, 161
\item Smart Car, 136
\item Smith, James, 60
\item Smola, 63
\item snow, 243
\item Snowdonia, 191, 192
\item social costs, 23
\item softwood, 284, 325
\item solar
\subitem farm, 208
\item solar chimney, 182
\item solar farm, 41
\item solar heating, 39
\item solar heating panels, 301
\item solar hot water, 205, 238
\item solar panels, 39
\subitem on cloudy day, 45
\item solar photovoltaics, 39
\subitem biggest plant in world, 48
\subitem world total, 41, 48
\item solar power, \bold{38}
\subitem concentrating, 40
\subsubitem parabolic trough, 178
\subitem in vehicles, 131
\item solar power station, 178
\item solar thermal electricity, 184
\item solar updraft tower, 182
\item solar warrior, 40
\item Solarcentury, 228
\item Solarpark, 41, 48, 216
\item Solartres, 184
\item Sol\'ucar, 184, 216
\item sorghum, 49
\item South Africa, 197
\item Southampton Geothermal District Heating Scheme, 98, 99
\item space shuttle, 219
\item spaceship, 29, 255
\item Spain, 178, 183
\subitem wind, 201
\item spark plug, 44
\item speed, 263, 307
\item speed-boat, 130
\item spelling, 328
\item spring tide, 81, 84
\item square in desert, 178, 236
\item stack, 22
\item stadium, 307
\item stainless steel, 325
\item standby, 69
\item standby power, 155
\item STE, 184
\item steak, 77, 79
\item steam engine, 6, 9
\item steel, 89, 94, 325
\subitem embodied energy, 94
\item steel production, 62
\item stereo, 69
\item Stern review, 221, 230
\item Stiglitz, Joseph, 221
\item Stirling engine, 184
\item stockpile stewardship, 220
\item stop-gap, 96
\item stop-sign, 255
\item storage
\subitem kinetic energy, 198
\subitem molten salt, 178
\item stove, 50
\item Strangford Lough, 85
\item Strathclyde University, 202
\item straw, 96, 288, 325
\item straw-burning power station, 286
\item streamlined, 255
\item street-light, 59
\item stuff, 13, 68, 88
\item submarine, 281
\item subsidy, 219
\item Sudan, 177, 338
\item sugar beet, 283
\item sugarcane, 49
\item sun, 96
\item sunlight, 243
\item sunniness, 38, 44
\item sunroof, 131
\item sunshine, 38
\subitem data, 238
\item superjumbo, 132
\item sustainable
\subitem definition, 157
\item sustainable coal, 158
\item Sustainable Development Commission, 2, 106
\item sustainable energy
\subitem environmental costs, 23
\subitem social costs, 23
\item SUV, electric, 138
\item sweater wearing, 205
\item Sweden, 190, 197, 208
\item swimming pool, 332
\item swirling air, 255
\item switchgrass, 49, 284
\item SWU, 102, 173
\indexspace
\item t-km, 118
\item tap, 24
\item tax, 219
\item taxman, 3
\item tea, 50, 332
\item Team Crocodile, 119
\item teaspoon, 69
\item technology, 115
\item telephone, 68
\item television, 68, 103
\item temperature, 50
\item temperature demand, 292
\item tenant, 227
\item tepid, 26
\item terrorism, 4
\item Tesco, 219
\item Tesla Roadster, 127
\item TEU, 95, 332
\item Texas, 182, 187, 201
\item th, 333
\item Thames Estuary, 64, 82, 83
\item The Skeptical Environmentalist, 2
\item thermal conductivity, 302
\item thermal fly-tipping, 301
\item thermal mass, 305
\item thermal solar, 238
\item thermal transmittance, 289
\item thermal, solar, 38
\item thermohaline circulation, 242
\item thermostat, 4, 141, 154
\item thin air, 240
\item Think, 136
\item thorium, 166, 174
\subitem in coal, 175
\subitem reserves, 166
\subitem resources, 166
\item thorium oxide, 166
\item three-wheeler, 138
\item thrust, 273
\item tidal barrage, 206
\item tidal friction, 96
\item tidal lagoon, 86, 206, 211, 321
\item tidal power, 82, 86
\subitem two basins, 320
\item tidal stream, 206
\item tidal wave, 83
\item Tiddles, 78
\item tide, 82, 237
\subitem as waves, 311
\subitem compared with wind, 86
\subitem explanation, 81
\subitem in oceans, 81
\subitem two-way generation, 311
\subitem UK resource, 321
\item tide is like wind, 315, 316
\item tide speed, 82
\item tide-pool, 82
\item timber, 325
\item Tina, 227
\item tinyURL, ix, 344
\item Titanic, 68, 69
\item TNT, 101
\item toaster, 50
\item toe, 329, 333
\item ton, 331
\item ton-km, 118
\item tonne, 331, \see{ton}{344}
\item Toyota Prius, 136
\item Toyota RAV4 EV, 138
\item toys, 68
\item traffic congestion, 124
\item traffic lights, 59
\item train, 118--120, 128, 258--260
\subitem freight, 92
\item transformer, 69
\item translation, 369
\item transmission, 209
\item transmission lines, 211
\item transmission losses, 104, 112, 151, 179, 180
\item transport, 203
\subitem efficiency, 79
\subsubitem bicycle, 119, 134, 259
\subsubitem catamaran, 282
\subsubitem eco-car, 119
\subsubitem electric car, 127
\subsubitem electric scooter, 138
\subsubitem freight, 92
\subsubitem plane, 36, 274
\subsubitem train, 119, 134
\subitem efficiency measures, 119
\item travel, 30
\subitem average, 30
\subitem emissions, 16
\item trees, 43, 49, 284
\subitem artificial, 249
\item TREV, 138
\item Trident, 221
\item triple glazing, 141
\item trolleybus, 120
\item tropics, 49
\item truth, 68
\item Tsukuba City, 268
\item tsunami, 83, 311
\item tube of air, 255
\item tumble dryer, 51
\item turbine, 145
\item turboprop, 35, 128
\item turn down, 154
\item turn-off-and-onable, 186
\item TV pick-ups, 196
\item Two-Seater Renewable Energy Vehicle, 138
\item two-way generation, 311
\item tyre, 258
\indexspace
\item U-value, 289, 294
\item UK, 21
\item UK coal, 6, 7, 9
\item UK electricity production, 342, 343
\item UK territorial waters, 61
\item uncertainty, 11
\item under-floor heating, 151
\item understanding, 16
\item underwater windmill, 83
\item unit conversion, 334
\item United Kingdom, 17, \see{UK}{344}
\item units, 24, 329
\subitem speed, 263
\subitem translation, 369
\item University of South Australia, 138
\item unplug, 72
\item untrustworthy foreigners, 5
\item updraft tower
\subitem solar, 182
\item uranium, 101, 166, 206
\subitem cost, 165
\subitem depleted, 163
\subitem extraction from seawater, 165, 174
\subitem in coal, 175
\subitem reserves, 2, 162
\item URL, \see{web pointer}{344}
\item US military, 102
\item USA, 99, 234, 237, \seealso{America}{344}
\subitem crops, 49
\item USS Akron, 280
\indexspace
\item vacuum cleaner, 71
\item vacuum cleaner, giant, 244
\item Vader, Darth, 68
\item Valentia, 312
\item vampire power, 155
\item Vancouver, 120
\item Vectrix, 138
\item vegan, 77
\item vegetarian, 4, 77
\item vegetarianism, 78
\item vehicle
\subitem electric, 127
\item vehicle to grid, 198
\item ventilation, 289, 296
\item Venturi Fetish, 138
\item Vestas, 64
\item vicious cycle, 243
\item Virgin, 277
\item Virgin Trains, 330
\item Viridian Solar, 39
\item viscosity, 309
\item VLS-PV, \see{very large scale photovoltaics}{344}
\item Volkswagen, 255
\item volt, 50
\item volume, 24, 331, 332
\subitem units, 332
\item vortex, 270
\item VRB power systems, 200
\indexspace
\item W(e), 333
\item Wales, 55, 60, 64, 78, 191, 268
\item Walkers crisps, 80
\item walking, 79
\item wall, 294
\item war, 100, 221
\subitem Iraq, 221
\subitem on drugs, 219
\item Wartsila--Sulzer, 262
\item washing, 51
\item waste food, 43, 48, 219
\item waste heat, 145
\item waste incineration, 26, 43, 206, 207, 212
\subitem efficiency, 213
\item water, 24, 36, 50
\subitem cost of, 92
\subitem desalination, 92
\subitem embodied energy, 95
\subitem hot, 50
\subitem pumping, 92
\subitem shallow, 310
\item water depths, 61
\item water power, 55
\item water vapour, 73
\item watercraft, 279
\item waterwheel, 56
\item watt, 68, 328
\item Watt, James, 6, 9, 328
\item wave, 73, 307, 308
\subitem deep-water, 307
\subitem Mexican, 307
\subitem production by boats, 92
\subitem shallow-water, 312
\subitem source of, 73
\subitem tides as waves, 311
\item wave speed, 82
\item wave-farm, 74
\item Wavegen, 75
\item wavelength, 307
\item we should have a plan that adds up, 163
\item weapons, 221
\item web pointer, ix
\item Weetabix, 42
\item Weier, Sven, 72
\item weight, 259
\item Wellington, 264
\item Wembley, 332
\item wheat, 286
\item White, David J., 60
\item white-tailed eagles, 63
\item Whitelee wind farm, 33
\item Whitstable, 60
\item Whorf, T. P., 19
\item Wicks, Malcolm H., 111
\item willow, 205, 283
\item wind, 32, 210, 235, 307
\subitem arguments against, 187
\subitem compared with tide, 86
\subitem cost, 66
\subitem data, 32, 34, 187, 265
\subitem deep offshore, 61, 66
\subitem intermittency, 187
\subitem Irish, 188
\subitem micro-wind, 63, 66
\subitem offshore, 60
\subsubitem cost, 66
\subsubitem jack-up barges, 63, 208, 216
\subsubitem London Array, 66
\subsubitem power density, 60
\subitem origin of, 73
\subitem Spain, 201
\item wind farm, 32, 214
\subitem Whitelee, 33
\item wind power and electric vehicles, 195
\item wind turbine, 34
\item Windermere, 192
\item windmill, 267
\subitem underwater, 83
\item window, 294
\item Windsave WS1000, 66
\item windspeed
\subitem Cairngorm, 32
\subitem Cambridge, 32, 34
\subitem data, 265
\item wing, 270
\item winter
\subitem heat pumps, 153
\item wood, 43, 49, 95, 284
\item Woodbridge, 82
\item woolly jumper, 141
\item world, 17, 105, 221, 231, 336--338
\item world coal, 6, 7, 9
\item world coal production, 7
\item world oil consumption, 284
\item world solar power, 41, 48
\item Wp, 333
\indexspace
\item Xebra, 137
\indexspace
\item Yamal, 133
\item Yes Minister, 228
\item yield, 48
\item you can have only one row, 315, 316
\indexspace
\item Ze-0, 137
\item zeppelin, 280
\end{theindex}
\ENDfullpagewidth
}
\normalsize
%\restoremargins
%\newpage
%\thispagestyle{empty}
%\input{draft.tex}
\newpage
\addtocontents{toc}{\protect\addvspace{10pt}}
\addcontentsline{toc}{chapter}{About the author}%
\begin{center}
{\Large \em Sustainable Energy -- without the hot air}
\\[0.1in]
{\large David JC MacKay}
\end{center}
\section{About the author}
David MacKay is a Professor in the Department of Physics
\marginpar[t]{
\begin{center}
\mbox{\epsfxsize=53mm\epsfbox{../../images/lc600.eps}}%
\end{center}
\begin{notindented}\raggedright\small\baselineskip 11.65pt plus 1pt minus 0.5pt
\item[] The author, July 2008.\par Photo by David Stern.
\end{notindented}
}%
at the University of Cambridge. He studied Natural Sciences at Cambridge
and then obtained his PhD in Computation and Neural Systems at the
California Institute of Technology.
%In 1992 h
He returned to Cambridge as a Royal
Society research fellow at Darwin College.
He is internationally known for his research in
machine learning, information theory, and communication systems, including
the invention of Dasher, a software interface that enables efficient
communication in any language with any muscle. He has taught Physics in
Cambridge since 1995. Since 2005, he has devoted much of his time
to public teaching about energy.
% He is an alumnus of The Climate Project (Cambridge, 2007).
He is a member of the World Economic Forum
Global Agenda Council on Climate Change.
\thispagestyle{empty}
\vspace{3in}
\vfill
%\small Version \thedraft\ (\today), \lowres{low-resolution}{high-resolution}
% edition.
%%% the last 3 pages
%\newpage
%\noindent %% cast of characters
%\mbox{\epsfbox{metapost/stacks.10}}
\newpage
\thispagestyle{empty}
% chart
\label{endGrid}
\begin{center}
\begin{tabular}{c}
\hspace*{-0.14in}\hspace*{-0.8in}{\Large{\bf{Power translation chart}}} \\[0.2in]
\hspace*{-0.14in}\hspace*{-0.8in}\epsfbox{metapost/stacks.1}\\[0.3in]
\begin{tabular}{*{2}{rp{62mm}}}
% %\small
1\,kWh/d & the same as \dfrac{1}{24}\,kW & ``UK'' & = 60 million people
\\
%\small
GW & often used for `{\bf{capacity}}' (peak output) \\
%% of a power facility \\
TWh/y & often used for average {{output}}
&
USA energy consumption: & 250\,kWh/d per person \\
1\,Mtoe & `one million \tonnes\ of oil equivalent'
% \newcommand{\europe}{125} in texdefns.tex
& Europe energy consumption: & \europe\,kWh/d per person
\\
\end{tabular}\\
\end{tabular} \medskip\\
\end{center}
\beginfullpagewidth\noindent
The most commonly used units in public documents discussing
power options are:\index{translation}\index{units!translation}
\medskip
\par
\begin{center}
\begin{tabular}{*{2}{l}}
\begin{minipage}[t]{75mm}
\raggedright
\begin{description}
\item[{\rm{terawatt-hours per year}}] (TWh/y).
\end{description}
\end{minipage}
&
\begin{minipage}[t]{81mm}
\raggedright
\begin{description}
\item[] 1000\,TWh/y per United Kingdom
is roughly equal to 45\,kWh/d per person.\medskip\par
%% 0.0456318
\end{description}
\end{minipage}
\\[0.1in]
\begin{minipage}[t]{75mm}
\raggedright
\begin{description}
\item[{\rm{gigawatts}}] (GW).
\end{description}
\end{minipage}
&
\begin{minipage}[t]{81mm}
\raggedright
\begin{description}
\item[] 2.5\,GW per UK is 1\,kWh/d per person.
\end{description}
\end{minipage}
\\[0.1in]
\begin{minipage}[t]{75mm}
\raggedright
\begin{description}
\item[{\rm{million tons of oil equivalent per year}}] (Mtoe/y).
\end{description}
\end{minipage}
&
\begin{minipage}[t]{81mm}
\raggedright
\begin{description}
\item[] 2 Mtoe/y per UK is
% One Mtoe per UK per year is 32/60 kWh/day per person.
roughly 1\,kWh/d per person.
% \par
% 1 Mtoe/y per UK is
%% One Mtoe per UK per year is 32/60 kWh/day per person.
% roughly 0.53\,kWh/d per person.
% 32/60
\end{description}
\end{minipage}\\
\end{tabular}
\end{center}
\ENDfullpagewidth
\newpage
\thispagestyle{empty}
\begin{center}
\begin{tabular}{c}
\hspace*{-0.8in}\hspace*{-0.8in}{\Large{\bf{Carbon translation chart}}}\\[0.2in]
\hspace*{-0.8in}\epsfbox{metapost/stacks.2}\\[0.3in]
\begin{tabular}{cc}
\begin{tabular}{rp{2.2in}}
%\small
kWh &
%\small
{\em{chemical}\/} energy exchange rate: \\
%\small
&
%\small
1\,kWh\ $\leftrightarrow$ 250\,g of \COO\ (oil, petrol)
(for gas, 1\,kWh\ $\leftrightarrow$ 200\,g)
\\
%\small
\kWhe &
%\small
{\em{electrical}\/} energy is more costly:
\\
%\small
& 1\,\kWhe\ $\leftrightarrow$ 445\,g of \COO\ (gas)
\\
& (Coal costs twice as much \COO)
%% ; nuclear power costs one twentieth (16g/kWh$^{\rm(e)}$).)
\\
%\small
t\,\COO & \tonne\ of \COO \\
%\small
Mt\,C & million \tonnes\ of carbon
% Mt\COO & million tonnes of \COO
\\
%\small
%% Gt\,\COO & billion tonnes of \COO \\
\end{tabular}
&
\begin{tabular}{rp{3.5in}}
%\small
``UK'' & = 60 million people\\
%\small
``World'' & = 6 billion people
\\
%\small
% UK: &
%\small
% 160\,Mt\,C per year (2005)\\
% USA: &
% $20\,$t\,\COO/y per person (1.5\,Gt\,C/y total)\\
% http://www.nef.org.uk/energyadvice/co2emissionsyr.htm
%\small
% World: & 7\,Gt\,C per year (2005)
% \\
\multicolumn{2}{p{3.5in}}{
%\small
%To avoid 2\,C global warming,
%need $< 2$\,Gt\,C/y
% \COO\ emissions need to be reduced to 2--3, according to some
}
\\
\end{tabular}\\
\end{tabular}\\
\end{tabular}
\end{center}
\newpage
\thispagestyle{empty}
\vspace*{3em}
\begin{center}
%\textbf%
{\huge\em Web site for this book}
\end{center}
\vspace*{2.5em}
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\begin{quote}
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\dvipsb{quick references - index}
{\ifnum \thelayouts=1{\layout*
\dvipsb{layoutb}}\else{\relax}\fi}
\end{document}