The major parties in the continuing debate as to whether ethanol's energy efficiency is better than that of other fuels has completed its most recent round of arguments with Michael Wang's presentation. He concludes that ethanol is better because it uses less fossil fuel in its production than gasoline does. My conclusions after this round of studies are no different than in my previous analysis. I agree with the Wang arguments.
Wang of Argonne National laboratories argues that what really matters is that ethanol compares favorably to gasoline, the fuel it replaces. His argument is that the fuel that uses the least fossil fuel in its production process, relative to its energy output, is the most desirable. He defines the Fuel Energy Ratio (FER) as ratio of the energy in the fuel being considered to the fossil fuel input to the fuel during its life-cycle of production. Ethanol comes out way ahead when compared to other fuels. Cellulosic ethanol has an FER of 10.31, corn ethanol: 1.88, coal: 0.98, gasoline: 0.81 and electricity: 0.46. He also finds that ethanol produced from corn achieves moderate reductions in greenhouse gases. Ethanol produced from grass and other "cellulosic" or woody biomass sources can achieve much greater energy and greenhouse gas benefits. He dismisses an ongoing academic argument about the amount of energy needed to produce ethanol.
A paper published in the March edition of "Natural Resources Research" by researchers at Cornell University and the University of California at Berkeley claims that ethanol production from corn requires 29 percent more energy than is provided by the resulting ethanol fuel. In contrast, a 2004 study by the U.S. Department of Agriculture (USDA) found that ethanol produces 67 percent more energy than is consumed in its production. The chart below, from Wang, shows how the preponderance of studies show that corn ethanol has a positive energy value that has increased with time.
Proponents of Shapouri argue that Pimentel continues to use outdated processes for the production of ethanol and includes energy from extraneous sources. They also contend that he attributes to much energy to the production of fertilizer and to the growing of the corn. Critics of Shapouri claim he omitted some energy inputs in the ethanol production system. Wang presented data showing how the amount of fertilizer used in corn production has decreased with time. Shapouri made the case for data that showed that the energy needed to grow corn is less than that used by Pimentel.
"DOE National Laboratory Expert Notes Energy Benefits of Ethanol", EERE News, 8/31/05
"Energy and Greenhouse Gas Emissions Impacts of Fuel Ethanol", Michael Wang, Argonne National Laboratory, 8/23/05
"Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower" , David Pimentel and Tad W. Patzek, National Resources Research, March 2005
"The 2001 Net Energy Balance of Corn Ethanol", Hosein Shapouri et al., USDA, June 2005