Environmental Sustainability Analysis of Biodiesel Production: A Comparative Analysis of Different Production Schemes

Due to their generally positive carbon dioxide balance, biofuels are seen as one of the energy carriers in a more sustainable future transportation energy system, but how good is their environmental sustainability, and where lie the main potentials for improvement of their sustainability? Questions like these require a life cycle perspective on the biofuel - from the cradle (production of the agricultural feedstock) to the grave (use as fuel). An environmental life cycle assessment is performed on biodiesel to compare different production schemes including chemical and enzymatic esterification with the use of methanol or ethanol. The life cycle assessment includes all processes needed for the production, distribution and use of the biodiesel (the product system), and it includes all relevant environmental impacts from the product system, ranging from global impacts like climate change and loss of non-renewable resources over regional impacts like acidification, eutrophication and photochemical ozone to more local impacts like ecotoxicity and physical impacts like land use, to allow judging on the overall environmental sustainability of the biodiesel and to support identification of the main focus points for improvement of the environmental sustainability.