Biomass ethanol: Technical progress, opportunities, and commercial challenges

Ethanol made from lignocellulosic biomass sources, such as agricultural and forestry residues and herbaceous and woody crops, provides unique environm ental, economic, and strategic benefits. Through sustained research funding , primarily by the U.S. Department of Energy, the estimated cost of biomass ethanol production has dropped from similar to$4.63/gallon in 1980 to simi lar to$1.22/gallon today, and it is now potentially competitive for blendin g with gasoline. Advances in pretreatment by acid-catalyzed hemicellulose h ydrolysis and enzymes for cellulose breakdown coupled with recent developme nt of genetically engineered bacteria that ferment all five sugars in bioma ss to ethanol at high yields have been the key to reducing costs. However, through continued advances in accessing the cellulose and hemicellulose fra ctions, the cost of biomass ethanol can be reduced to the point at which it is competitive as a pure fuel without subsidies. A major challenge to real izing the great benefits of biomass ethanol remains to substantially reduce the risk of commercializing first-of-a-kind technology, and greater emphas is on developing a fundamental understanding of the technology for biomass conversion to ethanol would reduce application costs and accelerate commerc ialization. Teaming of experts to cooperatively research key processing ste ps would be a particularly powerful and effective approach to meeting these needs.