The demand

While the world scrambles to prepare for alternatives to petroleum, concerns with corn-based ethanol--including its effect on rising food prices and its relative inefficiency--have become increasingly apparent. A promising alternative is cellulosic ethanol, which can be made from a variety of biomass feedstocks that place less demand on agricultural land and food-based crops. The amount of energy derived from cellulosic ethanol relative to the energy needed to harvest (known as the wells-to-wheels measurement) is also many times greater than that of corn-based ethanol. In December 2007, the Federal Government mandated the production of 36 billion gallons of ethanol annually by 2022, 21 billion of which is to come from cellulosic (non-corn-based) feedstock.