The Water Footprint of Bioethanol

Abstract

Concerns regarding energy security and climate changes have stimulated the development of renewable energy.Various countries have actively invested in research and development programs for renewable energy to reduce the dependence on fossil fuels.Bioethanol is the most commonly used biofuel in transportation.However, the trend of substantially increased transportation biofuel usage has caused competition over freshwater resources to increase.After energy problems, water resources are another critical topic worthy of exploration.This study involved analyzing the results of 150 studies regarding water footprints (WFs) between 2005 and 2013.Among the studies analyzed, only 4 involved discussion of WFs of bioethanol products.The bioethanol WFs in the various studies ranged from 790 L H 2 O/L EtOH to 11030.4L H2O/L EtOH.The minimal value was observed in sugar beets in aFrench study, and the maximum was observed in ethanol from molasses in Kanchanaburi, Thailand.WF expressions of bioethanol may vary according to the produce category, climate in which produce is grown, soil characteristics, and various production volumes or consumption methods.In addition, the total WF is not the only criterion for selecting the raw materials of bioethanol production.Produce that possesses a high green WF content and accommodates local climates should be selected with priority.The research results can provide a guideline for following studies in the field of bioethanol WF.Furthermore, the results can be used as a critical reference for selecting raw materials of bioethanol production.