Ethanol Creates Energy Gains


Posted on : 04-01-2012 | By : Mr. Green | In : Biofuel Industry, Cellulosic Ethanol, Ethanol Industry, Industry Issues
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Part 1: Does Ethanol Cost More Energy to Produce than to Use?

Does ethanol cost more energy to produce than to use?

Since the ethanol industry has been the first industry to prominently challenge the oil industry in the U.S. over the fuel market in almost a century a lot of criticism has been thrown towards ethanol.  Ethanol costing more energy to produce than to use has been one of the most common attacks against the ethanol industry.  This statement is not true and this three part series of blog articles looks to show you the origins and motivations behind this idea, debunking the data and discovering the flaws of the research behind ethanol costing more energy to produce than to use,  and eventually to show that ethanol can produce more energy than is used to produce it.

The biggest contributor towards the “ethanol produces a loss in energy” fallacy was written by University of Cornell Professor of Entomology David Pimentel and University of California, Berkley, Professor Tad Patzek in 2001.  Pimentel’s research is frequently used by supporters of the oil industry to try and bring down the credibility of ethanol as a source for fuel.  Furthermore their claims don’t stack up to the research that has been done by other scientists.

The only other studies that show ethanol costing more energy to produce than to use are all done in the 1980’s and early 1990’s.  It is possible that ethanol may have cost more energy to produce during those times but technology has improved since then even by the time Pimentel’s study had gone underway.  A year after Pimentel’s study was released the U.S. Department of Agriculture found that ethanol gives 34% more energy than it takes to produce it.  Below is a graph showing how Pimentel’s results aren’t matching up with current ethanol studies.

Pimentel’s study features a number of disputed claims and other problems in regards to how the experiments were performed and what they did and didn’t factor in.  These problems/disputed claims are:

  • Ethanol production yields a 29% loss in energy when produced from corn
  • Between 45% to 57% more energy would be lost in producing ethanol from wood or switchgrass
  • Pimentel’s study uses outdated information and data
  • Pimentel’s study uses data incorrectly
  • Pimentel’s study omits crucial data that could help determine ethanol’s energy production

Further hurting the Pimentel and Patzek study is Patzek’s connections with the oil industry.  At the University of California Patzek is the director of the schools oil consortium which is financially backed by Chevron and Phillips.  He also worked at Shell for over decade as a research consultant and expert witness.  These ties to oil indicate a bias in their study towards the oil industry, which has been working to remove ethanol from the fuel market, securing it exclusively for themselves.

Part 2 in this series will be focused on debunking Pimentel’s results and showing how some of the data collected from Pimentel’s research was old or outdated.



Pimentel/Patzek Article Oil Ties and Arguments

2002 U.S. Department of Agriculture Study

Pimentel Claims:,1

National Renewable Energy Laboratory See Section 7.1 Net Energy Balance

USDA Switchgrass yields

U.S. Ethanol Distiller Grains

Dry Mill Ethanol Efficiency Gains

Dry Mill Ethanol Efficiency (Thermal Energy) DGS in the U.S.


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