LCA and Water Footprint of biofuels used in transport sector: a review

Concerns over energy security and environmental impacts related to greenhouse gases emissions stimulate developments towards renewable energy. Over the last few years, there has been an intense debate about the major factors that determine the impacts of biofuels both in production and end use phase. The objective of this study is to review existing life cycle assessment (LCA) and water footprint (WF) studies on liquid biofuels used in transport sector to point out if: (i) LCA studies are adequate to evaluate the environmental impacts of biofuels; (ii) biofuels are environmentally sustainable when the WF is considered; (iii) it is possible to use both LCA and WF studies results to better assess the environmental sustainability of biofuels. Furthermore, different aspects of crops production are considered to assess the efficiency of the biofuels in the greenhouse gas emission reduction. The analysed LCA papers present quite different and at times contradictory results on biofuel environmental impacts. Variability in results is affected by crops used and geographical areas of cultivation and, consequently, the impact assessment of biofuels is consistent only at the local level. In conclusion, it can be stated that territory characteristics, weather conditions and farming methods should be considered to evaluate biofuels production.