Great Lakes Article:

How green is a soybean?
By Adam Hinterthuer
Earthwatch Radio
Published September 11, 2006

Ethanol and biodiesel are growing in popularity as alternatives to petroleum-based fuels. But the debate around these alternatives is growing as well. Critics say it takes more energy to produce these biofuels than what the fuels supply in return. A new study suggests that both fuels offer some benefits but neither of them can replace petroleum.
Jason Hill is a plant biologist and a researcher at the University of Minnesota in St. Paul. He worked on a study that examined the processes that turn corn into ethanol and soybeans into biodiesel. His team measured the gas used to run farm machinery and the energy used in biofuel production plants and everything in between. Hill says ethanol and biodiesel ultimately offer more energy that what is required to produce them.

"The ethanol production process returns approximately 25 percent more energy than you put in. The biodiesel production process returns approximately 93 percent more energy than you put in."
Hill's study was published this summer in the Proceedings of the National Academy of Sciences. He hopes it can point the way to other alternatives.

"By looking at differences between them, we were able to identify areas in the future where we can work to both maximize our energy return and also minimize our environmental impact."
Hill says all the soybeans in the United States would satisfy only half of the country's need for diesel fuel. And all the corn in the country would satisfy only 12 percent of the nation's appetite for gasoline. Hill says the best way to use biofuels in the near future might be blending them into petroleum-based fuels.