{"id":326,"date":"2011-08-15T14:41:08","date_gmt":"2011-08-15T18:41:08","guid":{"rendered":"http:\/\/antoine.wojdyla.free.fr\/blog\/?p=326"},"modified":"2012-06-20T18:31:15","modified_gmt":"2012-06-20T22:31:15","slug":"lenergie-renouvelable-sans-chichis","status":"publish","type":"post","link":"http:\/\/antoine.wojdyla.fr\/blog\/2011\/08\/15\/lenergie-renouvelable-sans-chichis\/","title":{"rendered":"L&#8217;\u00e9nergie renouvelable, sans chichis"},"content":{"rendered":"<p style=\"padding-left: 30px;\"><em>English readers : this post is about D. MacKay&#8217;s &#8220;<\/em><a href=\"http:\/\/www.inference.phy.cam.ac.uk\/sustainable\/book\/tex\/sewtha.pdf\" onclick=\"_gaq.push(['_trackEvent','download','http:\/\/www.inference.phy.cam.ac.uk\/sustainable\/book\/tex\/sewtha.pdf']);\" >Sustainable energy, without the hot air<\/a><em>&#8221; book.<br \/>\nYou should read it if it&#8217;s not already the case!<\/em><\/p>Un ami m&#8217;a fait lire un excellent livre sur l&#8217;\u00e9nergie durable : &#8220;<a href=\"http:\/\/www.amazon.co.uk\/Sustainable-Energy-Without-Hot-Air\/dp\/0954452933\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/www.amazon.co.uk\/Sustainable-Energy-Without-Hot-Air\/dp\/0954452933', 'Sustainable energy, without the hot air']);\" target=\"_blank\">Sustainable energy, without the hot air<\/a>&#8220;, disponible gratuitement sur internet (<a href=\"http:\/\/www.inference.phy.cam.ac.uk\/sustainable\/book\/tex\/sewtha.pdf\" onclick=\"_gaq.push(['_trackEvent','download','http:\/\/www.inference.phy.cam.ac.uk\/sustainable\/book\/tex\/sewtha.pdf']);\" >ici<\/a>), qu&#8217;il faut absolument lire si vous \u00eates un tant soi peu int\u00e9ress\u00e9 par ces questions.<\/p>Ce livre a \u00e9t\u00e9 \u00e9crit dans le but de centraliser toutes les informations disponibles sur les sources et les d\u00e9penses d&#8217;\u00e9nergie, afin que l&#8217;on puisse tout comparer sereinement les chiffres. En effet, l&#8217;auteur a remarqu\u00e9 que lorsque l&#8217;on parle d&#8217;\u00e9nergie, tout le monde emploie son propre syst\u00e8me d&#8217;unit\u00e9 opaque et inconsistant (kilowatt.heure, tonne-\u00e9quivalent p\u00e9trole, joule compos\u00e9s avec des secondes, des jours, des villes, etc.) Tout cela concoure \u00e0 cr\u00e9er un <em>hot air<\/em>, provoquant<a href=\"http:\/\/en.wikipedia.org\/wiki\/Obfuscation\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/en.wikipedia.org\/wiki\/Obfuscation', ' un confusion']);\" title=\"Obfuscation\"  target=\"_blank\"> un confusion<\/a> trop forte pour que le <em>layperson<\/em> n&#8217;aie la moindre envie de suivre.<\/p>\n<div id=\"attachment_341\" style=\"width: 764px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/antoine.wojdyla.free.fr\/blog\/wp-content\/uploads\/sewtha1.png\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/antoine.wojdyla.free.fr\/blog\/wp-content\/uploads\/sewtha1.png', '']);\" ><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-341\" class=\"size-large wp-image-341 \" title=\"Comparaison des pays\" src=\"http:\/\/antoine.wojdyla.free.fr\/blog\/wp-content\/uploads\/sewtha1-1024x338.png\" alt=\"\" width=\"754\" height=\"248\" srcset=\"http:\/\/antoine.wojdyla.fr\/blog\/wp-content\/uploads\/sewtha1-1024x338.png 1024w, http:\/\/antoine.wojdyla.fr\/blog\/wp-content\/uploads\/sewtha1-300x99.png 300w, http:\/\/antoine.wojdyla.fr\/blog\/wp-content\/uploads\/sewtha1.png 1148w\" sizes=\"auto, (max-width: 754px) 100vw, 754px\" \/><\/a><\/p>\n<p id=\"caption-attachment-341\" class=\"wp-caption-text\">Contribution des pays aux \u00e9missions mondiales de CO2 &#8211; pr\u00e9sent\u00e9 sous une forme tr\u00e8s parlante<\/p>\n<\/div><p>L&#8217;auteur prend soin de d\u00e9tailler TOUT ses calculs, et je dois avouer avoir appris beaucoup de choses sur le principe de fonctionnement de telle ou telle source d&#8217;\u00e9nergie car les r\u00e9flexions sont expos\u00e9es de mani\u00e8re tr\u00e8s p\u00e9dagogique. Le tout teint\u00e9 d&#8217;un humour tr\u00e8s british.<\/p><!--more-->Car l&#8217;auteur, <a href=\"http:\/\/fr.wikipedia.org\/wiki\/David_J._C._MacKay\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/fr.wikipedia.org\/wiki\/David_J._C._MacKay', 'David MacKay']);\" target=\"_blank\">David MacKay<\/a>, est un <a href=\"http:\/\/www.inference.phy.cam.ac.uk\/mackay\/\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/www.inference.phy.cam.ac.uk\/mackay\/', 'chercheur en math\u00e9matique \u00e0 Cambridge']);\" target=\"_blank\">chercheur en math\u00e9matique \u00e0 Cambridge<\/a>, red\u00e9couvreur des <a href=\"http:\/\/en.wikipedia.org\/wiki\/Low-density_parity-check_code\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/en.wikipedia.org\/wiki\/Low-density_parity-check_code', 'LDPC']);\" title=\"LDPC - wikip\u00e9dia\"  target=\"_blank\">LDPC<\/a>, et j&#8217;avais lu sans faire expr\u00e8s son autre livre, sur <a href=\"http:\/\/www.inference.phy.cam.ac.uk\/itprnn\/book.pdf\" onclick=\"_gaq.push(['_trackEvent','download','http:\/\/www.inference.phy.cam.ac.uk\/itprnn\/book.pdf']);\" target=\"_blank\">la th\u00e9orie de l&#8217;information<\/a>, tout aussi gratuit et excellent, dans un cadre plus professionnel. Ce travail sur le d\u00e9veloppement durable lui a valu d&#8217;\u00eatre nomm\u00e9<a href=\"http:\/\/www.decc.gov.uk\/en\/content\/cms\/about\/who_we_are\/management\/csa\/csa.aspx\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/www.decc.gov.uk\/en\/content\/cms\/about\/who_we_are\/management\/csa\/csa.aspx', ' conseiller scientifique']);\" target=\"_blank\"> conseiller scientifique<\/a> au d\u00e9partement de l&#8217;\u00e9nergie britannique &#8211; s&#8217;il pouvait traverser la manche&#8230;<\/p>\n<div id=\"attachment_342\" style=\"width: 238px\" class=\"wp-caption alignright\"><a href=\"http:\/\/antoine.wojdyla.free.fr\/blog\/wp-content\/uploads\/sewtha2.png\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/antoine.wojdyla.free.fr\/blog\/wp-content\/uploads\/sewtha2.png', '']);\" ><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-342\" class=\"size-full wp-image-342  \" title=\"Comparaison des alternatives\" src=\"http:\/\/antoine.wojdyla.free.fr\/blog\/wp-content\/uploads\/sewtha2.png\" alt=\"\" width=\"228\" height=\"487\" srcset=\"http:\/\/antoine.wojdyla.fr\/blog\/wp-content\/uploads\/sewtha2.png 296w, http:\/\/antoine.wojdyla.fr\/blog\/wp-content\/uploads\/sewtha2-140x300.png 140w\" sizes=\"auto, (max-width: 228px) 100vw, 228px\" \/><\/a><\/p>\n<p id=\"caption-attachment-342\" class=\"wp-caption-text\">Toute les \u00e9nergies renouvelables ont leur d\u00e9faut&#8230;<\/p>\n<\/div><p>On apprend notamment dans le livre que :<\/p>\n<ul>\n<li>Les radiateurs, bien qu&#8217;utilisant l&#8217;effet Joule, n&#8217;ont un taux de conversion electricit\u00e9 limit\u00e9. Il est de l&#8217;ordre 100%&#8230; Alors que l&#8217;on peut atteindre une efficacit\u00e9 de l&#8217;ordre de 400% avec une pompe \u00e0 chaleur.<em> There&#8217;s no such thing as a free lunch<\/em>&#8230;<em> except when you&#8217;re invited.<\/em><\/li>\n<li>Les \u00e9oliennes off-shore sont peu rentables &#8211; ch\u00e8res \u00e0 mettre en oeuvre pour un grain limit\u00e9 par rapport aux \u00e9oliennes terrestre.<\/li>\n<li>laisser son chargeur de t\u00e9l\u00e9phone branch\u00e9 n&#8217;a qu&#8217;une incidence minime  sur la consommation, alors que les routeurs (&#8220;box&#8221; des FAI) sont des <em>vampires \u00e0 \u00e9nergie<\/em>.<\/li>\n<li>Le nucl\u00e9aire ferait bien de se reconvertir au thorium ou revenir aux installations \u00e0 neutrons-rapides<\/li>\n<li>mettre un couvercle sur une casserole n&#8217;a pratiquement aucune incidence sur l&#8217;\u00e9nergie n\u00e9cessaire \u00e0 faire bouillir l&#8217;eau<\/li>\n<li>la d\u00e9salinisation de l&#8217;eau compte en \u00e9nergie l&#8217;\u00e9quivalent d&#8217;une augmentation de 7\u00b0C de sa temp\u00e9rature (<a href=\"http:\/\/withouthotair.blogspot.fr\/2010\/10\/making-numbers-stick-desalination.html\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/withouthotair.blogspot.fr\/2010\/10\/making-numbers-stick-desalination.html', 'ici']);\" target=\"_blank\">ici<\/a> en fait)<\/li>\n<\/ul><p>&nbsp;<\/p>&nbsp;<\/p>Et il y a ce passage, qui r\u00e9sume bien l&#8217;esprit du livre :<\/p>\n<blockquote><p>Have no illusions.<br \/>\nTo achieve our goal of getting off fossil fuels, these\u00a0 reductions in demand and increases in supply must be big. Don\u2019t be distracted\u00a0 by the myth that \u201cevery little helps.\u201d If everyone does a little, we\u2019ll\u00a0 achieve only a little. We must do a lot. What\u2019s required are big changes in\u00a0 demand and in supply.<\/p>\u201cBut surely, if 60 million people all do a little, it\u2019ll add up to a lot?\u201d<\/p>No.<br \/>\nThis \u201cif-everyone\u201d multiplying machine is just a way of making something\u00a0 small sound big. The \u201cif-everyone\u201d multiplying machine churns out\u00a0 inspirational statements of the form \u201cif everyone did X, then it would provide\u00a0 enough energy\/water\/gas to do Y,\u201d where Y sounds impressive. Is\u00a0 it surprising that Y sounds big? Of course not. We got Y by multiplying\u00a0 X by the number of people involved \u2013 60 million or so!<\/p>Here\u2019s an example\u00a0 from the Conservative Party\u2019s otherwise straight-talking Blueprint for a\u00a0 Green Economy:<br \/>\n\u201cThe mobile phone charger averages around&#8230; 1W consumption,\u00a0 but if every one of the country\u2019s 25 million mobile phones\u00a0 chargers were left plugged in and switched on they would consume\u00a0 enough electricity (219GWh) to power 66 000 homes for\u00a0 one year.\u201d<\/p>66 000? Wow, what a lot of homes! Switch off the chargers!<br \/>\n66 000 sounds a\u00a0 lot, but the sensible thing to compare it with is the total number of homes\u00a0 that we\u2019re imagining would participate in this feat of conservation, namely\u00a0 25 million homes. 66 000 is just one quarter of one percent of 25 million. So\u00a0 while the statement quoted above is true, I think a calmer way to put it is:\u00a0 If you leave your mobile phone charger plugged in, it uses one\u00a0 quarter of one percent of your home\u2019s electricity.\u00a0 And if everyone does it?\u00a0 If everyone leaves their mobile phone charger plugged in, those\u00a0 chargers will use one quarter of one percent of their homes\u2019\u00a0 electricity.\u00a0 The \u201cif-everyone\u201d multiplying machine is a bad thing because it deflects\u00a0 people\u2019s attention towards 25million minnows instead of 25million sharks.<\/p>The mantra \u201cLittle changes can make a big difference\u201d is bunkum, when applied\u00a0 to climate change and power. It may be true that \u201cmany people doing\u00a0 a little adds up to a lot,\u201d if all those \u201clittles\u201d are somehow focused into a\u00a0 single \u201clot\u201d \u2013 for example, if one million people donate \u00a310 to one accidentvictim,\u00a0 then the victim receives \u00a310 million. That\u2019s a lot. But power is a\u00a0 very different thing. We all use power. So to achieve a \u201cbig difference\u201d\u00a0 in total power consumption, you need almost everyone to make a \u201cbig\u201d\u00a0 difference to their own power consumption.<\/p><\/blockquote><p>En plus d&#8217;analyser la situation, il casse un bon nombre de mythes, p\u00e8se tous les inconv\u00e9nients et pr\u00e9conise des plans d&#8217;action, qu&#8217;il confronte \u00e0 une \u00e9ventuelle acceptation publique. Des probl\u00e8mes comme les fluctuations de la demande et le stockage de l\u2019\u00e9nergie sont \u00e9galement \u00e9tudi\u00e9s.<\/p>\n<p style=\"text-align: center;\">*\u00a0 *<br \/>\n*<\/p>En <a href=\"http:\/\/withouthotair.blogspot.fr\/2010\/12\/downwind-faster-than-wind.html\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/withouthotair.blogspot.fr\/2010\/12\/downwind-faster-than-wind.html', 'fouillant sur son blog']);\" target=\"_blank\">fouillant sur son blog<\/a>, j&#8217;ai appris<a href=\"http:\/\/www.fasterthanthewind.org\/\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/www.fasterthanthewind.org\/', ' la d\u00e9monstration et l\u2019existence d&#8217;engin \u00e0 vent']);\" target=\"_blank\"> la d\u00e9monstration et l\u2019existence d&#8217;engin \u00e0 vent<\/a> pouvant avancer dans la direction du vent \u00e0 une vitesse sup\u00e9rieure \u00e0 la vitesse du vent lui-m\u00eame &#8211; et pas qu&#8217;un peu : 2.8 fois!<br \/>\nPour quelqu&#8217;un qui fait de la voile comme moi, cela para\u00eet un peu surprenant, voire inconcevable. Et pourtant, rien n&#8217;emp\u00eache un tel ph\u00e9nom\u00e8ne.<\/p>Il suffit de ne pas utiliser de voile, o\u00f9 du moins pas comme on <a href=\"http:\/\/twodresslers.com\/Fun\/FunDocuments\/APSSailing.pdf\" onclick=\"_gaq.push(['_trackEvent','download','http:\/\/twodresslers.com\/Fun\/FunDocuments\/APSSailing.pdf']);\" target=\"_blank\">les utilise g\u00e9n\u00e9ralement <\/a>(de toute fa\u00e7on, m\u00eame si on arrive \u00e0 faire d\u00e9coller des avions, on ne sait toujours pas avec certitude pourquoi <a href=\"http:\/\/foils.wordpress.com\/2011\/12\/07\/portance-13\/\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/foils.wordpress.com\/2011\/12\/07\/portance-13\/', 'ces derniers volent']);\" target=\"_blank\">ces derniers volent<\/a> &#8211; <a href=\"http:\/\/drgoulu.com\/2012\/03\/11\/portance-pourquoi-ca-vole\/\" onclick=\"_gaq.push(['_trackEvent', 'outbound-article', 'http:\/\/drgoulu.com\/2012\/03\/11\/portance-pourquoi-ca-vole\/', 'via']);\" target=\"_blank\">via<\/a>). \u00c7a n&#8217;a rien de sorcier, mais \u00e7a d\u00e9fie le sens commun, habitu\u00e9 \u00e0 son rep\u00e8re immobile. Est-ce que le projet Blackbird de la San Jose State, sponsoris\u00e9 par Google, am\u00e8nera une nouvelle mani\u00e8re de consid\u00e9rer la navigation terrestre? On verra bien.<\/p><strong>edit<\/strong> (Mai 20012) :<\/p>Et une intervention TED pour David McKay !<\/p>\n<div id=\"_mcePaste\" class=\"mcePaste\" style=\"position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow: hidden;\">Sustainable energy, without the hot air<\/div>\n","protected":false},"excerpt":{"rendered":"<p>English readers : this post is about D. MacKay&#8217;s &#8220;Sustainable energy, without the hot air&#8221; book. You should read it if it&#8217;s not already the case!Un ami m&#8217;a fait lire un excellent livre sur l&#8217;\u00e9nergie durable : &#8220;Sustainable energy, without the hot air&#8220;, disponible gratuitement sur internet (ici), qu&#8217;il faut absolument lire si vous \u00eates [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12,6,9],"tags":[],"class_list":["post-326","post","type-post","status-publish","format-standard","hentry","category-francais","category-mood","category-science"],"_links":{"self":[{"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/posts\/326","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/comments?post=326"}],"version-history":[{"count":15,"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/posts\/326\/revisions"}],"predecessor-version":[{"id":418,"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/posts\/326\/revisions\/418"}],"wp:attachment":[{"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/media?parent=326"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/categories?post=326"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/antoine.wojdyla.fr\/blog\/wp-json\/wp\/v2\/tags?post=326"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}