How Energy-Positive is Ethanol, Really?

Thanks to state and federal energy policy (steered in large measure by the agriculture lobby), ethanol has become one of the most popular forms of renewable vehicle fuel in the US. However, if you consider everything that goes into making ethanol, as well as its byproducts and waste products, does it truly represent a net increase or decrease in overall fossil energy consumption?

The Bush administration is more pro-ethanol than ever. In his latest state of the union address, President Bush called on Congress to “fund additional research in cutting-edge methods of producing ethanol, not just from corn, but from wood chips and stalks, or switch grass. Our goal is to make this new kind of ethanol practical and competitive within six years.”

But can ethanol really offer the energy gains promised by the President? In July 2005 scientists David Pimentel and Tad W. Patzek published a controversial paper challenging the energy economics of ethanol and biodiesel. According to their research, the process of converting plants such as corn, soybeans, and sunflowers into fuel consumes much more energy than the resulting ethanol or biodiesel generates. Specifically, they said:

* Corn requires 29% more fossil energy than the ethanol produced

* Switch grass requires 45% more fossil energy than the ethanol produced

* Wood biomass requires 57% more fossil energy than the fuel produced

SEJ