So is Ethanol a Net-Energy Producer or Not?

Controversy surrounds the use of ethanol, because, with certain exceptions, it is not regarded as a net energy producer. Could you please comment? ESB, Irvine, CA

Most studies show the production of ethanol fuels from the 1990’s and onward to have a positive energy balance, meaning more energy comes from using the ethanol as a vehicle fuel than making it. My coauthored book published in 1985, The Forbidden Fuel (Bernton, Kovarik, and Sklar), covers this issue and my recent article in Ethanol Producer Magazine in June 2005 elaborates on how to practically produce ethanol fuels entirely on renewable energy. The Environmental Protection Agency announced in March 2006, that it has proposed a rule that would raise the emissions threshold for corn milling plants that produce ethanol fuel, allowing those plants to emit up to 250 tons per year of air pollutants before triggering tougher restrictions on production. Currently, corn-milling plants can emit 100 tons of pollutants per year. This was an attempt, sadly, to allow ethanol production facilities to use dirtier fuels, which is highly unnecessary. Many issues impact energy balance including the use of petroleum fertilizers in growing the resource or utilization of other forms of nutrients such as manures and composted organic materials, whether waste biomass ‘behind the fence’ of the ethanol plant is used for drying the biomass (a very heavy energy user) and for fermentation heat. Older studies highlighted Brazil where the sugar industry was very energy intensive and used lots of old diesels – so energy intensity was poor. The newer sugar and ethanol plants are much more efficient. There have been numerous studies on ethanol fuels energy balance and the strongest are by Shapouri and Duffield of USDA’s Office of Energy Policy and New Uses, and Wang from the Center for Transportation Research, Energy Systems Division, Argonne National Laboratory. Their July 2002 studies estimated the Net Energy Value (NEV) of corn ethanol. However, variations in data and assumptions used among the studies have resulted in a wide range of estimates. This study identifies the factors causing this wide variation and develops a more consistent estimate. They conclude that the NEV of corn ethanol has been rising over time due to technological advances in ethanol conversion and increased efficiency in farm production – and the research shows that corn ethanol is energy efficient as indicated by an energy output / input ratio of 1.34. Quoting from their Agricultural Economic Report No. 813: “Corn ethanol is energy efficient…for every BTU dedicated to producing ethanol there is a 34% energy gain… Only about 17% of the energy used to produce ethanol comes from liquid fuels, such as gasoline and diesel fuel. For every 1 BTU of liquid fuel used to produce ethanol, there is a 6.34 BTU gain.” Full report (PDF file, 176 kb): In “How Much Energy Does It Take to Make a Gallon of Ethanol?”, David Lorenz and David Morris of the Institute for Local-Self Reliance (ILSR) state: “Using the best farming and production methods, the amount of energy contained in a gallon of ethanol is more than twice the energy used to grow the corn and convert it to ethanol.” A 1992 ILSR study, based on actual energy consumption data from farmers and ethanol plant operators, found that the production of ethanol from corn is a positive net energy generator. In this updated paper the numbers look even more attractive: more energy is contained in the ethanol and the other by-products of corn processing than is used to grow the corn and convert it into ethanol and by-products (see report at second link). In contrast, Cornell professor David Pimental has been on a long time crusade to prove otherwise, and is about the only one I can find who claims the energy balance is negative. But on another note, the issue is a somewhat esoteric one. If we are using domestic coal to provide energy to produce liquid fuels, or even better, domestic renewable energy — even if ethanol had a negative energy balance – wouldn’t the benefits still be extremely positive? The US would import less petroleum from non-democratic countries, our trade deficit would be lower, and our tail pipe emissions would be less in most emissions categories. The use of ethanol and now biodiesel are critically important renewable energy options for our country. The energy balance is positive, and we must insure that their production meets traditional emissions standards, so consumers get the optimum energy/environmental resource. Scott Sklar
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Scott, founder and president of The Stella Group, Ltd., in Washington, DC, is the Chair of the Steering Committee of the Sustainable Energy Coalition and serves on the Business Council for Sustainable Energy, and The Solar Foundation. The Stella Group, Ltd., a strategic marketing and policy firm for clean distributed energy users and companies using renewable energy, energy efficiency and storage. Sklar is an Adjunct Professor at The George Washington University teaching two unique interdisciplinary courses on sustainable energy, and is an Affiliated Professor of CATIE, the graduate university based in Costa Rica. . On June 19, 2014, Scott Sklar was awarded the prestigious The Charles Greely Abbot Award by the American Solar Energy Society (ASES) and on April 26, 2014 was awarded the Green Patriot Award by George Mason University in Virginia.

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