<DrumBeat: September 6, 2007 The Oil Drum This Week in Petroleum 9-06-07>

99 comments on EROEI Short #4: Bootstrap-EROEI

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marcosdumay on September 6, 2007 - 1:34pm Permalink | Subthread | Parent | Comments top

"...when it reaches infinity. But that's not the point, is it?"

Actualy, I had two points. One is to evidence an error of the post, that does not take away all its meaning, but can lead to wrong interpretations sometimes.

My second point it that it doesn't really matter if our energy source has EROEI if 50, 100, 1000 or 10^9. But it really does matter if its EROEI is 1.3.

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SensibleEnergy on September 6, 2007 - 2:05pm Permalink | Subthread | Parent | Comments top

It is of limited value to talk about EROEI in isolation.

What if the EROEI was 1.3 but it had a 1 sec turnover rate.
Every second you would have 30% more energy that you had the second before. Or what if the the EROEI was only 1.3 but required almost no equipment or labor. Would it really matter then?

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ANewLand on September 6, 2007 - 3:22pm Permalink | Subthread | Parent | Comments top

You are correct in one sense that eroei only becomes an issue as the net energy (see clifman's analysis) approaches 1 or zero. Then the externalities of the effort (labor devoted to energy acquisition 'stolen' from other social goods, negative environmental damage,et) become very important issues.

If as you said the primary energy source requires no equipment or labor to harvest and process then it would have an infinite energy return.

If the primary energy source requires lots and lots of equipment and labor to extract (for instance a fossil fuel from the ground or wind from the air) then it could have negative eroei.

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luisdias on September 7, 2007 - 5:47am Permalink | Subthread | Parent | Comments top

You are correct in one sense that eroei only becomes an issue as the net energy (see clifman's analysis) approaches 1 or zero. Then the externalities of the effort (labor devoted to energy acquisition 'stolen' from other social goods, negative environmental damage,et) become very important issues.

... which is an assumption without real study. If the energy used would be more mechanized and without human input (a perfect machine that would function without human intervention for centuries, for example - and yes, I know it sounds like sci-fi, but we are getting into that), it wouldn't really mean a thing if the EROEI was 1.3. It would only be of importance if the energy output was not enough for our needs. Machines would be restless.

Of course, I'm not endorsing it. The problem with EROEI = 1.3 or smth like it is that it is more risky. If the production line explodes, or major malfunctions, or whatever, you may easily get EROEI < 1. And that's very bad.

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99 comments on EROEI Short #4: Bootstrap-EROEI

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