Potential bioethanol production from sweet sorghum on marginal land in China

Sweet sorghum is one of the best renewable non-grain energy crops for ethanol production due to its high sugar content, short growing period and good tolerance to natural conditions. However, insufficient studies have been conducted on the spatial distribution of sweet sorghum-based bioethanol production potential. This study presents a method, i.e., a land surface process model (Environmental Policy Integrated Climate GIS-based (GEPIC) model) coupled with a life cycle analysis (LCA), to simulate the spatial distribution of potential bioethanol production, energy efficiency and environmental impacts throughout the whole life cycle of sweet sorghum-based ethanol. The results showed that approximately 49.65 million ha of marginal land in China were suitable for sweet sorghum planting, and more than 13.57 million tons of sweet sorghum could be yielded. Based on sweet sorghum, 847.81 thousand tons of ethanol could be produced. A potential net energy gain of 115 billion MJ which is equivalent to 2.38 million tons of 90-octane gasoline would be achieved if all marginal lands could be used. The results of the environmental impact assessment showed that the total environmental effect index was 0.25 million (population equivalents). The global warming potential was the most significant environmental impact category. Guizhou Province can be given priority for sweet sorghum-based bioethanol development in China. (C) 2019 Elsevier Ltd. All rights reserved.