Corn is better used for re-fueling people and animals than cars and trucks, according to Greg Stephanopoulos, W.H. Dow Professor of Chemical Engineering and Biotechnology. “Corn’s production is energy-intensive and its conversion to biofuels is inefficient,” he said. “Cellulosic biomass feedstocks are better renewable resources for biofuels.”
In the United States, some states now require gasoline to be blended with up to 10 percent ethanol. The Energy Independence and Security Act of 2007 will require fuel producers to use at least 36 billion gallons of biofuels by 2022. Most of this increase is expected to be ethanol-produced right now through the fermentation of either starch-based food products such as corn kernels or sugar-based food products such as sugar cane.
Second-generation biofuels are made from a wider variety of nonfood sources, such as cellulose, algae and recovered waste products. Cellulosic ethanol produced from native prairie perennial switchgrass, plus agricultural forestry and municipal residues such as wood chips and paper sludge, has the greatest potential to become a viable primary transportation sector energy carrier, experts agree.
Among switchgrass’s benefits are essentially zero net emissions of greenhouse gases and improved fertility from the carbon that switchgrass replaces in the soil as it grows. In future scenarios, farmers could keep soil fertile for by rotating switchgrass with food crops. – Deborah Halber