Jason Hill, PhD, Research Associate in the Department of Applied Economics at the University of Minnesota at St. Paul, Erick Nelson, PhD, Postdoctoral Economist at the Stanford University Natural Capital Project, and David Tilman, PhD, Regent’s Professor and McKnight Presidential Chair in Ecology at the University of Minnesota at St. Paul, et al., wrote in their June 2, 2006 study “Environmental, Economic, and Energetic Costs and Benefits of Biodiesel and Ethanol Biofuels,” published in the Proceedings of the National Academy of Sciences :

“To be a viable substitute for a fossil fuel, an alternative fuel should…provide a net energy gain over the energy sources used to produce it.

Biofuel production requires energy to grow crops and convert them to biofuels. We estimate farm energy use…including energy use for growing the hybrid or varietal seed planted to produce the crop, powering farm machinery, producing farm machinery and buildings, producing fertilizers and pesticides, and sustaining farmers and their households. We also estimate the energy used in converting crops to biofuels, including energy use in transporting the crops to biofuel production facilities, building and operating biofuel production facilities, and sustaining production facility workers and their households…

In short, we find no support for the assertion that either biofuel [corn ethanol or soy biodiesel] requires more energy to make than it yields. However, the NEB [net energy balance] for corn grain ethanol is small, providing ~25% more energy than required for its production. Almost all of this NEB is attributable to the energy credit for its DDGS [distillers’ dry grain with solubles] coproduct, which is animal feed, rather than to the ethanol itself containing more energy than used in its production. Corn grain ethanol has a low NEB because of the high energy input required to produce corn and to convert it into ethanol.”