The Future is Now: What You Need to Know About Ethanol (E3076)
Nearly all of the ethanol manufactured in the United States today comes from corn.
Nearly all of the ethanol manufactured in the United States today comes from corn. Ethanol from corn is often referred to as first generation biofuel. Corn is relatively simple and inexpensive to distill into ethanol and to date has been the crop of choice for expansion of the ethanol markets. Corn will continue to play an important role in U.S. ethanol production. However, second generation biofuels, derived from biomass feedstocks, is where future expansion in the ethanol industry will occur. Biomass feedstock is typically derived from agricultural plants and from wood grown in forests, as well as from waste residues generated in the processing or use of these resources.
Plant cells contain cellulose, hemicellulose and lignin in cell walls (see Fig. 1). Cellulose and hemicellulose are made up of linear and branched chains of sugars. Plant cell walls can be broken down to expose the cellulose and hemicellulose, which can then be converted into basic sugars. The sugars can then be fermented into ethanol and other biobased products, much as corn ethanol is produced. Conversion rates for various processes and feedstocks vary tremendously. It is estimated that it will take a billion tons of biomass feedstocks per year to meet production goals set forth in the Energy Independence and Security Act of 2007. This goal seems lofty, but it is quite realistic, although it will require a diverse portfolio of feedstocks.