Ethanol generates 35% more energy than it takes to produce, according to a recent study by Argonne National Laboratory conducted by Michael Wang. The finding goes against a belief among many that ethanol production uses more energy than it creates.

Some critics of corn ethanol have argued that it has a negative energy balance, which means the energy in ethanol itself minus fossil energy used for corn farming and ethanol production.

The new findings support earlier research that determined ethanol has a positive net energy balance, according to the National Corn Growers Association. That research was conducted by USDA, Michigan State University, the Colorado School of Mines, the Institute for Local Self-Reliance and other public and private entities. A USDA study released in 2004 found that ethanol may net as much as 67% more energy than it takes to produce.

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The US Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy said the Argonne study should help quell debate about the net energy balance of ethanol.

"We believe (the study) has laid to rest some long-held misunderstandings about ethanol and its important role in reducing America's reliance on imported oil and our greenhouse gas emissions," DOE officials stated in a summary of the study. "In terms of key energy and environmental benefits, cornstarch ethanol comes out clearly ahead of petroleum-based fuels."

In the last 10 years, only two studies, both of which were conducted by Cornell University entomologist David Pimentel, have found the net energy balance of ethanol to be negative. Many economists have argued Pimentel used outdated data in his methodology.

In the last 30 years, corn yield per unit of chemical inputs has gone up significantly. At the same time, energy use by ethanol production plants has gone down significantly, Argonne has found in the past.

Argonne suggests some researchers fail to accurately account for solar energy when determining ethanol's energy balance.

"Some of the confusion arises over the fact that some of the total energy used in the production of ethanol is 'free' solar energy used to grow the corn in the first place," DOE states. "Since the solar energy is free, renewable and environmentally benign, we shouldn't care."

Ethanol also has a positive benefit in greenhouse gas (GHG) emissions reduction, according to the Argonne study. Wang found that, on a per gallon basis, corn ethanol reduces GHG emissions by 18-29%, National Corn Growers Association says.

The US now uses about 3 billion gallons of fuel ethanol a year, only Brazil uses more fuel ethanol.

Argonne is one of the US Department of Energy's largest research centers.

Read a report about the new study on the National Corn Growers Association Web site here