Grasses and legumes for cellulosic bioenergy

The simplest process for obtaining energy from biomass is direct combustion, in which the full energy content of the biomass is released as heat during the conversion of organic material plus oxygen to carbon dioxide plus water. Sugarcane, including specific varieties referred to as “energy cane,” is the most notable success story in the development of a proven perennial cellulosic bioenergy crop. Switchgrass has received more attention as a potential bioenergy crop than any other perennial plant in the United States, thanks to its status as the herbaceous model species for the U.S. Department of Energy’s Feedstock Research Program, initiated in 1992. Harvesting perennial grasses and legumes as biomass feedstocks can usually be done with the same equipment and harvesting systems used for forage crops. Carbon sequestration by switchgrass has been found to be nearly ubiquitous across a broad range of growing conditions, and at rates higher than most agricultural production systems.