(374be) Technoeconomic Evaluation of Sorghum as Bioenergy Feedstock
According to the Energy Independence and Security Act of 2007 (EISA), the U.S. targets to produce 36 billion gallons of renewable transportation fuels annually by 2022. Of this amount, 15 billion gallons is to be provided by conventional corn-starch-based ethanol, 16 billion gallons is to be provided by cellulosic ethanol, and the balance is to be from other advanced biofuels. Sorghum has the potential to be a major player in the ethanol production scheme because of its high yield, drought-tolerant nature, and production of lignocelluloses, sugar and starch. Starch from grain sorghum and sugar in sweet sorghum stalk can be converted to ethanol. Additionally, cellulosic ethanol can be produced from sorghum biomass. The feasibility study of using sorghum as a cellulosic ethanol feedstock is currently underway at NREL. The study includes the technoeconomic analysis, a methodology that has been used to guide the research and development of lignocellulosic biofuels production processes at NREL for over two decades. Results obtained from the technoeconomic analysis of the biochemical production of ethanol from three different sources of sorghum biomass, namely forage sorghum, sweet sorghum bagasse, and grain sorghum stover, will be presented. The minimum ethanol selling price (MESP) for each biomass feedstock using a discounted cash flow rate of return analysis (DCFROR) will be determined and compared with that from corn stover. Additionally, the cost of ethanol production from grain sorghum starch will be determined and compared with that from shelled corn starch. Technoeconomic analysis on the production of ethanol from sweet sorghum juice will also be studied.