Harvesting Corn Stover
Green Car Congress reported that a new analysis by researchers at the University of California, Berkeley anticipates that cellulosic ethanol promises to make ethanol “a truly green fuel with significantly less environmental impact than gasoline… The UC Berkeley team calculated a Net Energy Value (Output energy – Input energy) for corn ethanol of 4.5 MJ/Liter. Cellulosic ethanol fares much better, with a calculated Net Energy Value of 22.8 MJ/L.”
Such research results bolster the position taken by federal, state and private efforts to develop cellulosic ethanol as an alternative fuel, e.g., :
- At the federal level, the Biomass Initiative is now in its fourth year
- A cornerstone of a new energy plan announced by the Governor Pataki is greater biofuel production and use in the New York State
- Renewable energy business analysts are watching carefully the success of new efforts such as the Iogen Corporation.
The researchers used a Biofuels Meta Model to analyze “six separate high-profile—and contradictory—studies”.
The goal of the UC Berkeley analysis was to understand how six studies of fuel ethanol could come to such different conclusions about the overall energy balance in its production and use. They assessed the studies’ assumptions and then reanalyzed each after correcting errors, inconsistencies and outdated information regarding the amount of energy used to grow corn and make ethanol, and the energy output in the form of fuel and corn byproducts.
The researchers concluded that ethanol from corn uses less petroleum energy than gasoline production. They also concluded that reduction in greenhouse gases due to the use of corn ethanol as an alternative fuel is “smaller than some thought—only between 10% to 15%.” The researchers also noted that using corn for ethanol production has other negative environmental impacts associated with fertilizer, pesticide and herbicide use. Nevertheless, the researchers clearly stated that those who say ethanol from corn is negative energy are wrong.
O.K., after seeing the Biofuels Meta Model report plus observing the caliber of people who at the recent Plug-in Partners news conference were endorsing plug-in, flex-fuel hybrid electric vehicles, e.g., Callahan, Romm and Woolsey, I will stop being so negative about ethanol.
Reference
“Ethanol can contribute to energy and environmental goals”; Farrell, A.E., R.J. Plevin, B.T. Turner, A.D. Jones, M. O’Hare, and D. Kammen; Science, 311. 506 – 508 (2006)
2 Comments
A more revolutionary bioconversion technology than Iogen’s for fermenting cellulosic ethanol has been developed by BRI Energy, LLC. Instead of enzymatic hydrolysis (which requires the use of expensive enzymes to break cellulose down to sugar prior to fermentation) BRI’s syngas fermentation technology gasifies the feedstock, scrubs the syngas, and literally feeds it to their own patented bacteria that secretes ethanol and water. It is far cheaper, faster, and efficient than other processes with all the benefits that we have come to associate with cellulosic ethanol.
Well, my knee-jerk response is that Shell’s syngas opens the door to coal-to-liquids, against which Joe Romm cautioned at the press conference. It keeps copious consumption by the consumer in the hands of Big Oil and, thus, effectively fails to change the essential pattern.
I believe a more fundamentai change needs to occur. Big Electric, Little ICE means we use less fuel, rather than simply switching fuels. Electric motors are more efficient and the electricity infrastructure is as efficient and frankly, more stable, than going to the syngas station.
Am I in favor of cleaner coal technologies? Yes. And, I suppose if you showed me that such fermentation technology was a means to cleaner coal and other feedstock such as papermill waste, I would say there is a role for it.
In any case, there is quite a bit of information at Green Car Congress about syngas, so I need to examine this alternative fuel that garners Rockefeller investment in Chinese development more closely. The little I recall is that DME does much better with green house gases than does BTL.
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[...] UC Berkley researchers helped to confirm for me that ethanol is a sustainable fuel. I have seen contradictory claims. Is cellulosic ethanol is a better source of energy than ethanol from gasification? Also, a lingering doubt is whether the harvesting of agricultural waste is better than returning it to the soil to be broken down into micro-nutrients. Another question is which is the best use of biomass? Burn it for combined heat and power, and then use the electricity to charge the batteries in your electric vehicles. Or, gasify it for ethanol (or some other alternative fuel) plus heat and power, and then use the ethanol and the electricity in your plug-in, flex-fuel vehicle? [...]
[...] * Note: In which the author puts in a plug for plug-in, flex fuel hybrids, and, later, mentions the recent UC Berkeley meta study. alternate fuel, renewable energy [...]