Although many experts have indicated that the production of ethanol from cellulosic plant biomass is the way of the future, the technology has never gone completely to full-scale commercialization. However, the recent announcement of the United States Department of Energy to invest $386M for ethanol biorefineries in the next four years may signal the start of bringing commercialized cellulosic ethanol production at the forefront of the biofuels market. Six biorefineries have been identified. According to Department of Energy Secretary Samuel W. Bodman, “these biorefineries will play a critical role in helping to bring cellulosic ethanol to market, and teaching us how we can produce it in a more cost effective manner”. Non-food biomass sources are considered for use as raw materials for the proposed plants, including (1) agricultural residues (wheat straw, corn stover), (2) industrial plant wastes (saw dust, paper) and (3) cellulosic energy crops (switch grass). Relative to corn-based ethanol, cellulosic ethanol is said to have a higher net energy with lower emissions of greenhouse gases..