Environmental and energy performance of ethanol production from the integration of sugarcane, corn, and grain sorghum in a multipurpose plant

Abstract

Although in the last 40 years only sugarcane has been harnessed for the production of ethanol in Brazil, corn production has grown strongly in certain areas, and may serve as a supplementary feedstock for ethanol production in integrated plants during the sugarcane off-season. The aim of this study is to evaluate the environmental and energy performance of ethanol production from sugarcane, corn, and grain sorghum in a Flex Mill in the state of Mato Grosso, Brazil. A life cycle assessment was carried out to survey the production of ethanol from each individual feedstock, and the integration of two of these to increase production during a one-year period. Results indicate that the environmental and energy performance are greatly influenced by agricultural activities, highlighting the importance of sugarcane cultivation. Still, there was an increasing trend of Climate Change impacts, Human Toxicity (carcinogenic) and Ecotoxicity, as well as reduced impact of Photochemical Oxidant Formation and Energy Return on Investment (EROI) as the proportion of ethanol from starchy sources in integration scenarios increases.