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124 comments on Oilwatch Monthly - January 2008
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124 comments on Oilwatch Monthly - January 2008
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According to the US Department of Agriculture in a 2004 study, ethanol returns energy at the rate of 1.67:1 over the course of its entire supply chain so the net energy gain, in 2004, was 167% vs energy invested. The USDA study was confirmed by follow-on studies by Argonne National Laboratory and the University of Nebraska among others.
Those against ethanol development often cite studies from the 1970s and 80s that don't take into account modern efficiency gains, technological advancement, and economies of scale for current ethanol production. Energy return on energy invested increased from 1.25:1 in 1995 to 1.67:1 in 2004 according to USDA studies. It is reasonable to assume that with continued scaling, ethanol EROI will continue to increase rapidly until the market matures.
This issue met heated debate in Congress in the period of 2002 - 2005. The debate resolved many issues underlying ethanol and due, in part, to strong gains in EROI a major initiative to increase ethanol production was supported.
Energy return on energy invested increased from 1.25:1 in 1995 to 1.67:1 in 2004 according to USDA studies. It is reasonable to assume that with continued scaling, ethanol EROI will continue to increase rapidly until the market matures.
That's not actually what happened. They changed the way they were accounting for the energy. The 1.67 ratio came from them assigning more of the energy inputs to the co-product credits - just sleight of hand.
First, I just want to say that I think a grid supported transportation system is the most preferable option. So I'm a major supporter of an electric based transportation system and bridge energy systems like hybrids and PHEVs. I see ethanol and other biofuels, which I don't believe will ever be produced in volumes great enough to match current oil production, as part of the solution. At best, I can't see biofuels ever topping more than 10mbpd. But if a high cost fuel can delay the peak a little longer while incentivizing the transition then I'll support it as a practical option.
That said, I want to address your statement directly and I'm not doing it out of any disrespect whatsoever for your research. Just to say it seems strange that you'd attribute this increase to an accounting change. Can you show me, in the report, where they changed the accounting? Otherwise, it's your word against the USDA.
In the interest of fairness, I'm going to post a number of related reports:
http://www.calrenewablefuels.com/pdfs/Energy%20Balance.pdf
http://www.nytimes.com/2006/06/25/business/25ethanolside.html
http://www.carbohydrateeconomy.org/library/admin/uploadedfiles/How_Much_...
Some state the USDA's findings. Others support the debate.
And Robert, I saw your R2 blogs, so you needn't repost them here. I guess I fall in the camp that supports ethanol as a bridge fuel and doesn't agree with the negative EROEI arguments.
So for my part, here is my opinion/analysis:
1. Biofuels help mitigate the peak.
2. Corn ethanol eeks out a net energy return with more positives in sugar cane, and potential cellulosic.
3. All biofuels help lead us away from oil and promote energy independence which is, overall, a good thing.
4. Energy diversity is, in my opinion, the best way to deal with contracting supply. IMO the preference should be on the options that move us away from fossil fuels.
5. The US is strong in agriculture and, long term, can win with biofuels.
6. I think that all sides of the field are likely to have skewed their reports to bias their respective interests. A shame, really.
Biofuels are going to be remembered as a great tragedy. Read Stuart's "Fermenting the Food Supply" and this article:
http://www.earth-policy.org/Updates/2008/Update69.htm
At maximum we could get 10% of our liquid fuels at a cost of billions starved. The energy returns are marginal, so biofuels buy us very little time for a huge capital investment. Far better, cheaper, and more ethical to require more efficient vehicles by law.
The fairest way to state ethanol's EROEI is as follows:
Pimentel and Petzak's original studies used old averages for productivity and inputs. That would be about the equivalent of bringing currently unfarmed marginal land into corn production and old conversion technology. Pimentel's first studies didn't even include an accounting for the value of the co-product. Figure EROEI in the range of .9 to 1.2
Using average farm productivity and average technology, figure between 1.2 and 1.75 EROEI.
Using the latest technology AND setting up a system where the ethanol plant is next to a feedlot, so the distiller's grains don't need to be dried for transport purposes, and you can reach 1.9 EROEI or so. The drying of distiller's grains sucks a lot of natural gas, so if you can eliminate that step, efficiency is improved. You can truck distiller's grain wet, but only for short distances due to economics. You cannot ship distiller's grains by rail while it is wet.
As to the problem of accounting for co-products, part of the difficulty is that the corn is transformed from largely a starchy source of calories, to a source of protein (DDG). Probably the best ways to account for the change in composition would be to either use the relative feed value ratings, or examine the monetary value of the input corn to the value of the output distiller's grain (dried or not) and use the ratio of the prices to determine what percentage of the corn was "used up" in the ethanol conversion.