Biofuel yields have been overstated by as much as 100 percent, according to a study by researchers at the University of Wisconsin-Madison Nelson Institute of Environmental Studies (www.ies.wisc.edu) and the University of Minnesota (www.umn.edu). The study, published in the journal Environmental Research Letters (www.iop.org/EJ/erl), says the overstatement of biofuel yield estimates is due in large part to a failure to account for local differences in climate, soils, technology and other factors that influence agricultural outputs.

The researchers who authored the study, say they hope to offer an analysis of biofuel yields that accounts for local differences in an effort to help countries make wiser choices about whether to invest in ethanol or biodiesel, which crops to plant, and how best to use existing farmlands.

The Nelson Institute’s Center for Sustainability and the Global Environment (SAGE, www.sage.wisc.edu), examined historical biofuel yield data in an effort to differential yields on a geographic basis. What it found was that biofuel yields varied widely based on where the source crop was grown. For example, the yield data for corn ethanol produced in the United States was found to be pretty close to accurate, while the average yield of corn ethanol in developing nations was nearly 100 percent overstated.

To review the data produced as a result of this study, click here.