by kublikhan » Wed 23 Jul 2014, 21:15:20
Sunweb, Prieto and Hall's book is not the end all be all of "True Science". There are plenty of "True Science" studies out there that disagree with their numbers. Surf wrote up a rebuttal last time someone linked to this:
$this->bbcode_second_pass_quote('Surf', 'E')ROEI is nothing more than watts in to make it and the Watts it produces. Anything that is not required to produce energy should not be included.
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Security cameras and electric alarms do consume a small amount of electricity. The 138.6 GW?H/Year factor he applies for security is in my opinion simply ridiculously large.
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Premature phase out??? Since when does Obsolescence effect the power generation or power required to make something. If a piece of equipment is obsolete but still works and is still being used it will not effect EROEI. And again the 148.4 GWh/year factor is way too big.
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All of this section is not an energy cost or necessary energy expenditure. They are simply optional financial cost. As far as I know there is no mathematical formula that links dollars to watts. Without such a link dollars spent cannot be considered a watt in or watt out.
Prieto and Hall EROEI calculations have come up before on Peakoil.com. Basically they make one massive mistake in there analysis. They assume Dollars = Watts. It does not. Some people get paid a lot of money for sitting at a desk and doing nothing (or nearly nothing) Others get paid little but do a lot of work. Since most of the cost for anything is the money spent to pay workers, assuming Dollar = watts is simply wrong.
A good EROEI excludes labor. Then electricity, oil, and gas (all in watts or BTUs) is used to make it is totaled up to generate the energy in number. And then all the watts or BTUs of electricity , oil, and gas produced is totaled to generate the energy out number. And then finally the Energy out is divided by energy in to great the EROEI number.
The vast majority of researchers do it right and generate numbers significantly higher than the 2.45 EROEI number Preto and Hall came up with.
And if you wanted to look at one of those "True Science" studies, here you go:
$this->bbcode_second_pass_quote('', '[')b]Abstract:
A high energy return on energy investment (EROI) of an energy production process is crucial to its long-term viability. The EROI of conventional thermal electricity from fossil fuels has been viewed as being much higher than those of renewable energy life-cycles, and specifically of photovoltaics (PVs). We show that this is largely a misconception fostered by the use of outdated data and, often, a lack of consistency among calculation methods. We hereby present a thorough review of the methodology, discuss methodological variations and present updated EROI values for a range of modern PV systems, in comparison to conventional fossil-fuel based electricity life-cycles.
ConclusionsImprovements in PV technologies over the last decade have brought about notable increases in their EROI. When calculated in terms of the electricity output per unit of primary energy invested (Eqn. 2), The EROIel of PV ranges from 6 to 12, which makes it directly comparable to that of conventional thermal electricity without CCS.
When instead calculated according to the often employed formula EROIPE-eq =T/EPBT (Eqn. 4), i.e. expressing the energy ‘returned’ by PV in terms of its ‘Primary Energy equivalent’, the EROI of PV is up to 19 to 38, which puts it squarely in the same range of EROI as conventional fossil fuels.
These new results prove that PV is already a viable energy option that may effectively contribute to supporting our societal metabolism, while significantly reducing the depletion of the remaining stocks of non-renewable (fossil) primary energy, and mitigating the concurrent environmental impacts in terms of global warming and polluting emissions.
However, even these remarkable results should not allow one to forget that PV, like all other renewable technologies, must still be supported by an initial investment of primary energy, which is, as of today, of fossil origin. We therefore argue that available monetary and energy resources should be funnelled in the right direction without delay, lest not enough high-EROI fossil fuels are left to support demand during times of gradual shift to renewable resources.
Authors:
Marco Raugei*1,2, Pere Fullana-i-Palmer1 and Vasilis Fthenakis2,3
1 UNESCO Chair in Life Cycle and Climate Change, Escola Superior de Comerç Internacional (ESCI) – Universitat Pompeu Fabra, 08003 Barcelona, Spain
2 Center for Life Cycle Analysis, Columbia University, New York, NY 10027, USA
3 National Photovoltaic Environmental Research Center, Brookhaven National Laboratory, Upton, NY 11973, USA