The Ethanol Papers - Paperturn manuscript - Flipbook - Page 417
biomass to build a biofuel industry that could meet energy needs for the poor
and develop a sustainable local fuel supply, a future much better than using
fossil fuels.”
“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. Farrell, Kammen, and their UC Berkeley colleagues dissected each study and recreated its analysis in a spreadsheet where
they could be compared side-by-side. The team said it found numerous "errors,
inconsistencies and omissions" among the studies, such as not considering the
value of co-products of ethanol production - dried distillers grains, corn gluten
feed, and corn oil - that boost the net energy gain from ethanol production. Other
studies overestimated the energy used by farm machinery.”
"The assumptions made by some of the authors were not based on the best
data, or were just a little bit too convenient, and had a strong impact on the
results," Kammen said.”
Included in the UC Berkeley review were the following:
Thermodynamics of the Corn-Ethanol Biofuel Cycle Patzek, T.W., Critical Reviews in Plant Sciences 23(6), 519-567 (2004). Ethanol Production Using Corn,
Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower
David Pimentel and Tad W. Patzek, Natural Resource Research, 14(1), 65-76
(2005).
Another study, conducted by the United States Department of Agriculture, was
presented in 2007 at UC Berkeley – what a coincidence - by Roger Conway,
Office of Energy Policy and New Uses at the United States Department of Agriculture (USDA). The report showed huge discrepancies in the figures that Pimentel and Patzek used to arrive at their conclusions versus the figures used
by USDA’s efforts to conduct their own studies on ethanol vs. gasoline EROEI.
The USDA studies were significantly more favorable towards ethanol production.
A Michigan State University study conducted by Bruce Dale, Professor of
Chemical Engineering, found that the Pimentel-Patzek methodology is flawed.
The measurements of BTU are irrelevant and that the net energy of ethanol is
actually higher than gasoline (in other words, EROEI for ethanol is positive,
while the EROEI of gasoline is more negative).
