Environmental impact of oil-based biofuels production processes

Three scenarios of energy production from sunflower seeds in a rural context are compared. The analysis refers to the district of Pisa, in Italy, and it accounts for production of sunflower seeds, conversion of seeds into different biofuels (crude oil, refined oil and biodiesel) and production of thermal and electrical power from biofuels in CHP engines. The environmental impacts of each scenario were compared by applying the methodology of life cycle assessment (LCA). The use of all the three types of biofuel allows a reduction of fossil CO2 emissions of 400-460 g/MJ of produced electricity respect to a traditional diesel fuel. On the other hand all biofuel scenarios have a higher impact than diesel in the categories respiratory inorganics, terrestrial ecotoxicity, terrestrial acidification/nutrification due to polluting emissions deriving from seed cultivation. The life cycle analysis shows that the biofuel upgrading processes (refining and transesterification) as well as crude oil transport have a low influence on the environmental performance, compared to seed cultivation, which is the most impacting step. On the other hand, crude oil upgrading allows a significant reduction in pollutant emissions during combustion. As a result, biodiesel results the most sustainable biofuel in the analysed context. 1