Analyzing life-cycle water footprint for advanced bio-liquid fuel: Crop residues and non-grain biofuels in China

Abstract

Increasing the production of biofuels in some provinces of China may be affected by local water resources (WR). This study analyzed the life-cycle water footprint (WF) of second-generation and non-grain fuels in different natural and technical conditions in different provinces of China. The analysis was doing using the CROPWAT software model, comparing conversion technologies, a sensitivity analysis, uncertainty analysis, and a pressure analysis of local WR. The impact of biofuel on the WF and local water load in Northeast, Southwest, Northwest, Central, and South China were analyzed. Results show that the bio-ethanol of Bagasse and Cassava in Guangxi, Sorghum stalk in Jilin, and Paddy Rice straw and Corn cobs in Heilongjiang are the most favorable feedstocks for producing biofuel, with WFs ranging from to 152–967 m3/t. The proportions of grey WF to life-cycle WF for Sorghum straw (61.89%), Corn cob bio-ethanol (60.17%), and Rapeseed biodiesel (85.20%) in China should be reduced compared with the global average WF (less than 50%). The local WR load of Wheat straw in Henan was the highest (K = 1.13) and the local WR load of Bagasse in Guangxi was lowest (K = 0.06). Increasing the output, reducing the value fraction of the crop residue, and reducing chemical fertilizer consumption have the best effect on reducing WF. Biofuel development policies, including adopting well-designed management practices, controlling fertilizer use as much as possible, carrying out nearby bioenergy strategies, and implementing a local multi-cooperation model are proposed. These results can guide provincial decision-making to expand biofuel commercialization in China.