Environmental life cycle assessment of bioethanol production from wheat straw

Ethanol produced from lignocelluloses is expected to make a major contribution on transportation fuel markets. In this paper, a life cycle assessment was carried out to assess the environmental burdens of ethanol production from wheat straw and its use as ethanol blend fuels. Two ethanol based fuel E15 (a mixture of 15% ethanol and 85% petrol by volume) and E85 (85% ethanol and 15% petrol by volume) were assessed and results were compared to those of conventional petrol (PT) in 1 km driven by an equivalent car. The environmental performance was studied using ReCiPe methodology and includes global warming, ozone depletion, photochemical oxidant formation, acidification, ecotoxicity, eutrophication, water depletion and fossil depletion. The results show that, compared to petrol, life cycle greenhouse gas emissions are lower for ethanol blends, with a 73% reduction for an E85-fuelled car and 13% reduction with E15. A modest savings of 40% in fossil depletion was also found when using E85 and 15% when using E15. Similar results are also observed for ozone depletion. The findings highlight a number of environmental issues such as acidification, eutrophication, ecotoxicity and water depletion for which areas ethanol blend use does not offer any advantages compared with petrol. A further analysis of ethanol production at well to gate level helps identify the key areas in the ethanol production life cycle. The results indicate where effort needs to be placed to improve the technology performance and process design which can help in lowering the environmental impacts in the whole life cycle. (c) 2012 Elsevier Ltd. All rights reserved.