Reducing greenhouse gas emissions is a critical goal of the newly minted Obama administration and 111th Congress. A newly published report (“Improvements in Life Cycle Energy Efficiency and Greenhouse Gas Emissions of Corn Ethanol”) in the Journal of Industrial Ecology, a highly respected journal for research on life cycle analysis of industrial and agricultural systems, concludes America's ethanol industry is energy efficient and doing its part to reduce greenhouse gas emissions by 48 percent to 59 percent compared to gasoline.
The report, completed by a team of researchers at the University of Nebraska led by Dr. Ken Cassman, concluded: “Direct effect GHG emissions were estimated to be equivalent to a 48 percent to 59 percent reduction compared to gasoline, a twofold to threefold greater reduction than reported in previous studies.”
This newly published work, based in part on information compiled by the Department of Energy's Argonne National Laboratory, is critical to educating the Environmental Protection Agency, the state of California, and other entities looking at ethanol's capacity to reduce greenhouse gas emissions from liquid transportation fuels.
The report also found that the eight corn-ethanol scenarios had net energy ratio (NER) values from 1.29 to 2.23, meaning ethanol returned 29 percent to 123 percent more energy than was required for its production.
Other key findings of the report include:
Ethanol-to-petroleum output:input ratios were 10:1 to 13:1 for today's typical corn-ethanol systems but could increase to 19:1 with progressive crop management that increases both yield and input use efficiency. A closed-loop biorefinery with an anaerobic digestion system reduces GHG emission by 67 percent and increases the net energy ratio to 2.2. Such improved performance moves corn-ethanol much closer to the hypothetical estimates for cellulosic biofuels.
These results suggest that corn-ethanol systems have substantially greater potential to mitigate GHG emissions and reduce dependence on imported petroleum for transportation fuels than reported previously.
“This research further underscores the importance of American ethanol production in meeting our goals of reducing both greenhouse gas emissions and our dependence on foreign oil,” said Renewable Fuels Association President Bob Dinneen. “A new and more complete understanding of the benefits of ethanol versus gasoline in reducing greenhouse gas emissions is needed to better inform the debate about the costs and benefits of all energy sources including petroleum and renewable forms of fuel like ethanol.”