No en­ergy an­swer is all green

The Weekend Australian - Review - - Clean Energy - Keith Orchi­son

RE­NEW­ABLE en­ergy will be the fastest grow­ing sec­tor of the mar­ket over the next 20 years ac­cord­ing to lead­ing an­a­lysts, but the prob­lem is that it is not ac­tu­ally ‘‘ green’’, says one of Amer­ica’s lead­ing en­vi­ron­men­tal sci­en­tists.

Speak­ing in Ade­laide where he ad­dressed a ma­jor pe­tro­leum con­fer­ence, Jesse Ausubel of the Rock­e­feller Univer­sity in New York de­cried ‘‘ an era of mass delu­sion’’ about re­new­able en­ergy.

Ausubel, di­rec­tor of the univer­sity’s Pro­gram for the Hu­man En­vi­ron­ment, has im­pec­ca­ble green cre­den­tials as one of the sci­en­tists who led the United Na­tions in to its work on global warm­ing, re­jects hy­dro­elec­tric­ity, wind and so­lar power and biomass as ‘‘ re­new­able, but not green.’’

The best way to un­der­stand the scale of de­struc­tion th­ese en­ergy forms im­pose, says Ausubel, is to de­nom­i­nate each in watts per square me­tre that they can pro­duce as a power source. A square kilo­me­tre of a hy­dro­elec­tric dam, he ar­gues, pro­duces enough power for about 12 peo­ple while se­verely dam­ag­ing river life, while a biomass power plant re­quires about 2500sq km of prime farm­land to equal the out­put of a 1000 MW nu­clear plant on a few hectares.

‘‘ Wind­mills, to equal the same nu­clear plant, need to cover 800sq km — and that in a very favourable cli­mate. Pho­to­voltaics re­quire 150sq km.’’ Ausubel says a wind en­ergy sys­tem re­quires 130 times as much steel and 30 times as much con­crete to match the out­put of a nat­u­ral gas com­bined cy­cle power sta­tion.

Re­solv­ing wind and so­lar’s prob­lems of in­ter­mit­tent sup­ply will re­quire a large amount of stor­age bat­ter­ies and their heavy met­als, he adds, point­ing out that re­new­able en­er­gies also in­voke high risk as sup­ply sources in a chang­ing cli­mate. ‘‘ Rain may no longer fall where we build dams or plant biomass for fuel. The wind may no longer blow where we build wind­mills while coal, meth­ane and ura­nium plants will op­er­ate re­li­ably around the clock day af­ter day.’’

Ausubel pre­dicts that so­lar re­new­able power will ul­ti­mately ‘‘ be­come an em­bar­rass­ing col­lec­tion of stranded as­sets.’’

He is a strong ad­vo­cate for deal­ing with en­ergy needs un­der cli­mate change by build­ing large zero- emis­sion power plants us­ing nat­u­ral gas ini­tially, and then nu­clear power much more widely to reach an age when pure hy­dro­gen com­pletes the process of eco­nomic de­car­bon­i­sa­tion.

It will prob­a­bly take a cen­tury, he says, be­fore the hy­dro­gen age is in place, ‘‘ but the in­ex­orable de­cline of car­bon seems clear.’’

Ul­ti­mately, says Ausubel, the be­hav­iour of the end user drives the en­ergy sys­tem. ‘‘ When the end user wants elec­tric­ity and hy­dro­gen, the pri­mary sources that can pro­duce on the needed scale while meet­ing ever more strin­gent ( en­vi­ron­men­tal) con­straints will win. Dense cities will be the fi­nal ar­biter of the en­ergy sys­tem.

‘‘ My dream is 5000MW gas- fu­elled, ze­roe­mis­sion power plants op­er­at­ing at high tem­per­a­tures and high pres­sures, and thus su­per com­pact. Like the in­ter­net and com­put­ers, the en­ergy sys­tem must be­come more pow­er­ful and smaller to be deeply green.’’

Cau­tious: Ausubel

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