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I've never managed to successfully engage with people who think that ERO[E]I is the only stat that matters, and that it proves that fossil fuels are the only possible answer, and that peak oil means we're doomed. And the Oil Drum seems to have quite a few of those people.

One thing I would note here, that is given energy intensity per unit GDP has been tending to decrease in the industrial & post-industrial world, one might even  make an argument that a future joule is worth more than a present joule. But I absolutely agree with your final line that "The answer to this question is not philosophical and depends solely on the relative abundance of energy at both epochs."

EROEI makes me yawn. It's just not interesting. Cost of net energy production is interesting; the non-monetised impacts are interesting; the macroeconomic impacts are interesting; even grid balancing is interesting. But EROEI? It's a red herring to distract from the real discussions, just as comparisons of power per unit land area are.

by LondonAnalytics (Andrew Smith) on Wed Mar 28th, 2012 at 07:30:01 AM EST
I would say that EROEI is a good tool to sort away solutions that fail to deliver as much energy as it took to produce them. Is it for example energy-smart to run buses in Sweden on Italian wine? If it isn't that is no reason to stop as long as CAP delivers an over-production of wine anyway, but one should not fool oneself into believing that all motor vehicles can run on Italian wine.

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by A swedish kind of death on Wed Mar 28th, 2012 at 07:49:13 AM EST
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If EROEI < 1, then there is no meaningful cost of net energy - the denominator is negative. If EROEI > 1, then it's a potential energy source, and what's interesting is the cost of net energy.

Re running buses on fuel: any bus will run at less than 100% efficiency, so its EROEI is less than 1. As for its fuel, an EROEI < 1 doesn't necessarily matter, because now we're talking about energy vectors rather than energy sources.

A fuel with EROEI < 1 can be perfectly viable, if it's converting a less portable energy source into a more portable one. For example, synthetic hydrocarbons created from grid electricity have an EROEI < 1, but turn grid electricity into a fuel that can power planes, ships and HGVs. And once that process is cheap enough, it's a much better option than oil.

Italian wine is irrelevant. Or, more specifically, EROEI is irrelevant to it. The two limiting factors on Italian wine are that its water content is too high for a fuel, and the total possible production isn't very high.

by LondonAnalytics (Andrew Smith) on Wed Mar 28th, 2012 at 08:26:00 AM EST
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Yes, but a fuel with EROEI < 1 that is not converting a less portable energy source into a more portable one is not viable.

Like ethanol from Italian wine.

Ett ägg under foten hellre än sprit i tanken - NyTeknik An egg under your foot rather than liquor in the tank - NyTeknik
Inte ens när det gäller utsläpp av koldioxid erbjuder Stockholms etanolbussar någon miljömässig fördel. Stockholms Lokaltrafik köper nämligen etanol gjord på italienskt vin. Odling, tillverkning och transporter ger så stora utsläpp av koldioxid, att vanlig dieselolja är bättre. Even when in emissions of carbon dioxide offers Stockholm ethanol buses no environmental benefit. Stockholm Transport buys namely ethanol made from Italian wine. Cultivation, production and transport produce such large emissions of carbon dioxide, to regular diesel oil is better.


Sweden's finest (and perhaps only) collaborative, leftist e-newspaper Synapze.se
by A swedish kind of death on Wed Mar 28th, 2012 at 12:33:30 PM EST
[ Parent ]
Yes, but a fuel with EROEI < 1 that is not converting a less portable energy source into a more portable one is not viable.

It's entirely usual for energy vectors to have EROEI < 1 - electricity transmission does, heat transmission does, gas transmission does, and so on. The conversion to ethanol, and transportation to Sweden is just another energy vector with EROEI < 1. It's not great from an exergy perspective; but there may be other benefits, and it can easily be viable short term. (obviously, it can only be viable long-term if there's sustainable exergy going in at the top - but again, that's not an EROEI issue, it's a question of sustainable energy sources).

In this particular case, if ethanol results in lower local pollution, then it's not necessarily a bad deal. I mean, it may be a bad deal , but it may not be: they may just be trading off increases in a global pollutant (CO2) in exchange for decreases in local pollutants (PM10, PM2.5), which may be a sane trade-off for them. Worse than useless for mitigating global warming, but a benefit for local residents who get reduced exposure to particulates.

Again, EROEI is the wrong tool for the job: judging the merits of that trade-off would need an economic assessment of the relative damage costs.

by LondonAnalytics (Andrew Smith) on Sun Apr 1st, 2012 at 08:17:42 AM EST
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The two limiting factors on Italian wine are that its water content is too high for a fuel,

There are plenty of drunks who provide a counterexample, living entirely on Chianti.

by njh on Sun Apr 1st, 2012 at 12:39:47 PM EST
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