Cassava to Fuel Ethanol: Environmental, Economic, and Energy Impacts

摘要

China now seriously considers to blend fuel ethanol with gasoline for achieving at least three goals -1) to improve transportation fuel quality, 2) to supplement petroleum supply to China's transportation fuel market, and 3) to increase income for rural farmers. While corn is being considered for ethanol production in Northern China, tropical or subtropical crops could be used to produce ethanol in Southern China. Cassava, rich in starch, is one sub-tropical crop that can be used for this purpose. With support from China's central government, Guangxi province in Southwest China has undertaken a major task to evaluate the feasibility of producing ethanol from cassava. Planted area and output of cassava in Guangxi province are 60% of total Chinese planted area and output. Since cassava is not a human food as wheat and corn are, it could be a better ethanol feedstock than corn or wheat for populous China. Shanghai Jiao Tong University has been helping Guangxi province in evaluating the feasibility of introducing cassava-based fuel ethanol. A life cycle assessment (LCA) model has been developed at the university to evaluate the economic, environmental, and energy (EEE) impacts of converting cassava to ethanol as an alternative automotive fuel. This model is being used to assess the total economic cost to ethanol users, the environmental effect, and the energy requirement of the ethanol production pathway. The model includes these life-cycle stages: planting and transportation of cassava, conversion of cassava to ethanol, blending ethanol with gasoline, and fuel combustion. LCA results from this study, together with other considerations, are being used by the Guangxi autonomous region government to determining government investments and promotion policies for cassava-based fuel ethanol.