Biodiesel production from unconventional oilseed crops ( Linum usitatissimum L. and Camelina sativa L.) in Mediterranean conditions : environmental sustainability assessment

From an environmental point of view, diesel substitution with biodiesel shows many advantages but often involves environmental issues that must be assessed case by case. The environmental impact of Linum usitatissimum and Camelina sativa oilseed crops for biodiesel production was assessed by Life Cycle Assessment approach considering a cradle-to-gate perspective. The study included three steps: cultivation, oil seed transportation from farm to pressing plant and biodiesel production from vegetable oil by transesterification. The cultivation was carried out in Mediterranean conditions, with low inputs (minimum use of fertilisers and pesticides) and no irrigation. Seed production is responsible for more than 85–90% of the environmental impact of biodiesel; seed pressing represents less than 2% of the biodiesel environmental impact for most of the evaluated impact categories and transesterification ranges between 2% and 10%. For seed production, diesel fuel and exhaust gases emissions from the tractors' engines are the main factors responsible for the environmental impact, while pesticide and fertiliser production accounts for a small environmental load. In general, the differences between the performances of the two biodiesel fuels arise almost completely from the difference in the environmental impact of seed production and, in particular, from seed yield, which is higher for flax.