July 13, 2010
Good news for ethanol
Published in Agweek Magazine
The energy gain of corn made from ethanol is growing, a new federal study says.
Ethanol made from corn produces as much as 2.8 units of energy for every one unit of energy used to make the fuel, according to a U.S. Department of Agriculture report.
In a 2004 USDA report, the net energy balance of corn ethanol was 1.8.
Increased efficiency by both corn farmers and ethanol producers has led to ethanol's greater energy balance, according to the new report.
"Ethanol has made the transition from an energy sink, to a moderate net energy gain in the 1990s, to a substantial gain in the present." And there are still prospects for improvement, says the report from USDA's Office of the Chief Economist.
The report measured all conventional fossil fuel energy used in the production of one gallon of corn ethanol. It analyzed the results of a survey of 18 dry mill ethanol plants in Minnesota, eastern South Dakota, Iowa and Nebraska, as well as federal data on total direct and indirect energy inputs in producing corn.
The net energy balance ranged from 1.4 to 2.8, the report says.
The 1.4 measures only the ratio of energy in ethanol to the external energy used to create it.
After allowing for the heat used to produce byproducts, the energy ratio is between 1.9 and 2.3.
Some ethanol plants already use biomass power. When that's factored in, the energy ratio rises to 2.8, the report says.
The 1.4 ratio is the best and truest measure, says Cole Gustafson, biofuels economist with the North Dakota State University Extension Service in Fargo.
What's causing the gains?
Much more energy is required to manufacture ethanol from corn than to produce the corn itself.
But most of the gain in net energy balance is coming at the farm level, the report finds.
Nitrogen use per bushel has declined by about 20 percent since the mid-1990s, according to the report.
"When farmers get better, so do we," says Ron Lamberty, vice president of the Sioux Falls, S.D.-based American Coalition for Ethanol.
Gustafson notes that many farmers have used less nitrogen in recent years because of high fertilizer prices. He wonders whether they'll use more nitrogen if fertilizer prices decline, which would reduce ethanol's energy balance.
Ethanol's energy balance also is growing because ethanol yields have increased about 10 percent in the past 20 years, which means proportionally less corn is needed to produce one gallon of ethanol, the report says.
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