From the Journal Sentinel

Scientists and the U.S. Department of Agriculture have sparred for years over whether ethanol requires more energy to produce than it yields as fuel.

Professors at the University of California-Berkeley and Cornell University have published studies suggesting that ethanol production results in a net energy loss. The department argued that the studies used outdated information and included such factors as energy used in manufacturing farm equipment in the input equation.

In July, after more than three years of analyzing dozens of published reports and doing their own research, scientists at the University of Minnesota published a report concluding that ethanol produced from corn results in a 25% positive return on energy.

"We started with a fresh perspective," said Jason Hill, lead author of the study. "There was a lot said that was fair and unfair about all these studies."

Hill and other researchers found that the studies showing ethanol as a net loser used old data that didn't account for recent efficiencies in corn and ethanol production. But the researchers kept in the farm machinery numbers and even decided to add the home energy costs of the farmers tilling the land into their equation.

Much of the positive return comes from the byproducts of ethanol production, such as high-protein distiller grains for animal feed, Hill said. Without the co-products, ethanol would roughly break even in energy spent on production compared with energy gleaned.