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41 comments on A Life Cycle Assessment of Energy Products: Environmental Impact Assessment of Biofuels

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SensibleEnergy on September 19, 2007 - 12:45pm Permalink | Subthread | Parent | Comments top

Sparaxis

You’re not doing too well here. If you are not being dishonest then you are very confused.

1. "The promotion of sugarcane ethanol based solely on its lower fossil fuel needs is intellectually dishonest."
I don't see where Jack is doing this. He started out with this:

“Your statement that "fossil fuels are necessary to produce biofuels with a real return of less than 1" is either an intentional falsification, or displays ignorance inconsistent with the time you have spent at TOD.”

This relates to the EROEI, nowhere did he say that he was doing an exhaustive comparative study.

2. “I don't know you or your orientation, so I can't comment on that.”

What does this even mean? What are you talking about? What orientation? North-South, East West, sexual, does it matter?

3. “I didn't offer an opinion. I offered basic science facts, since I'm a scientist and that's what I do.”

Anyone can cite facts, but not everyone understands their relevancy.

“These studies make the energy return of sugarcane ethanol look so high because they both omit the non-fossil fuel inputs as energy (which they are) and because of co-production credits.”

Uh, but the EROEI calculation for oil doesn’t? Try including the oil energy as an input and see what kind of EROEI you get. Are the oil co-products given credits?

4. “CO2 isn't the only thing to be concerned about.”

Earlier you accused him of being concerned only about EROEI.

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Sparaxis on September 19, 2007 - 1:14pm Permalink | Subthread | Parent | Comments top

Yikes!

I'm not accusing Jack of anything. I don't know him. I'm sure he's a fine upstanding person. I'm accusing studies and reports that promote sugarcane ethanol based solely on its lower fossil fuel needs as being intellectual dishonest, in part because they tend to conflate fossil fuel energy with just "energy". Perhaps my pronouns were vague? Should have I used "one" instead of "you"?

The relevancy of the facts I cited is that it is thermodynamically impossible to get a 10:1 ENERGY return on sugarcane ethanol. It is possible to get a 10:1 FOSSIL energy return on sugarcane ethanol. Further, I distinguished that the focus on FOSSIL energy is fine if you are concerned about CO2.

I don't understand your point about "oil" EROEI. Are you talking about crude oil, in which case there are no coproduction credits involved? Or an oil product, which is the combination of a crude oil EROEI and a conversion efficiency?

I didn't accuse anyone about anything. I'm not the ad hominem type.

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SensibleEnergy on September 19, 2007 - 2:40pm Permalink | Subthread | Parent | Comments top

Ok, maybe I was too harsh, but here is my point: Do we really care about the EROEI of "ethanol" or do we care about the EROEI of sugar cane?

Wouldn't a lot depend on how the EROEI is defined?

Jack attacks a statement that fossil fuels were required to get an EROEI of greater than one. You respond by saying: No, it's EROFEI.

I really haven’t looked at the studies too much yet, but I don’t need to because your argument doesn’t make sense.

You can’t just say that EROEI can’t be 10 because it takes more than 8000 btu to distill it. If the energy to distill the ethanol comes from bagasse, then you do not count it as an input.

Please show why the studies are wrong, i.e. show that energy in the ethanol is less than ten times the energy that was invested. Use a starting point of a bare field and an endpoint of ethanol. Lets say I had a field, with an ethanol plant on it. The EROEI is the energy out of the field divided by the energy into the field.

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Jack on September 19, 2007 - 9:52pm Permalink | Subthread | Parent | Comments top

Thank you for keeping this going while I was asleep here in Thailand.

It seems clear that the original comment tacked on to Prof Goose's call to promote the story was an uneducated hit piece that doesn't show any evidence that the author even read the study.

However, Sparaxis does have a point, although it doesn't directly contradict mine. Yes, sugar cane-based ethanol looks very different on EROEI and EROFEI metrics, largely because of the use of bagasse to provide heat and sell power externally (which provides an offset).

If there were a perfect regulatory environment and significant use of energy in transport, things could be quite different. In that case, demand for electricity for bagasse could compete directly with demand for ethanol as a transportation fuel. Then, maybe the energy is bagasse would not belong to the sugar cane alone, but would be already a part of the energy system. Then, it would not be included in the ethanol EROEI calculations.

I am not a huge advocate of liquid biofuels. Over time, it seems to be crop acreage will be a base resource that goes into fuel production, like it or not. In that case, I think electricity is a far better pathway. But we are not there yet.

It seems that for developing countries in tropical regions, sugar-cane based ethanol makes sense economically and environmentally in the meantime. I don't have any problem with diverting sugar from the food chain. I do not think tropical forests are being impacted much by ethanol (although they may be for soy and palm oil) and do think that sugar cane for fuel will be largely unirrigated.

Corn-based ethanol seems to be completely bankrupt and would not even be looked at without subsidies in the forms for cash, free water and externalization of environmental damage. I don't think all ethanol sources combined will ever provide much more than 5% of liquid fuels.

But in the right environment and until transportation moves to electricity as a fuel source, I do think some ethanol can make sense.

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marcel_g on September 20, 2007 - 2:22am Permalink | Subthread | Parent | Comments top

Good remarks Jack, I share your opinions (electricity, Brasil-EtOH, USA-EtOH) as one of the authors of the study. Biofuels may be ok under very specific conditions, but for the future we have to look at alternatives with much higher efficiencies (yes, sunlight-to-electricity!). Biofuels produced out of organic wastes look very promising, but produced out of food it's not only problematic from an ethical point of view.

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Jack on September 20, 2007 - 3:07am Permalink | Subthread | Parent | Comments top

Thank you. I do think we are on the same page. I tend to agree that there are disturbing potential ethical issues related to competition between fuel and food. However, it is not as clear cut as some make it out to be.

One could make an argument that the poor benefit more from fuel than from sugar, tobacco, alcoholic beverages, etc. So, we would have to infer that there could be ethical issues involved in using so much land for these products. Likewise there is so much waste in processed foods and meat consumption.

Why do some people consider diverting sugar to ethanol as evil, when diverting corn to livestock feed is just fine?

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41 comments on A Life Cycle Assessment of Energy Products: Environmental Impact Assessment of Biofuels

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