Climate Assessment of Vegetable Oil and Biodiesel from Camelina Grown as an Intermediate Crop in Cereal-Based Crop Rotations in Cold Climate Regions

Abstract

The oilseed crop winter camelina (Camelina sativa) is attracting increasing interest for biofuel production. This study assessed the climate impacts of growing camelina as an intermediate crop in northern Europe (Sweden) for the production of vegetable oil and biofuel. Climate impacts were analyzed using life cycle assessment (LCA), while impacts on biodiversity and eutrophication were discussed. Three functional units were considered: 1 ha of land use, 1 kg of oil, and 1 MJ biofuel (hydrogenated vegetable oil, HVO). The results showed that dry matter yield over the whole crop rotation was higher in the camelina crop rotation, despite the lower yield of peas due to relay cropping with camelina. In the whole camelina crop rotation, fat production more than doubled, protein and fiber production marginally increased, and the production of carbohydrates decreased. Higher climate impacts related to field operations and fertilizer use in the camelina crop rotation, with associated N2O emissions, were compensated for by increased soil carbon accumulation due to the increased return of organic matter from the additional crop in the rotation. The total climate impact was around 0.5 kg CO2 eq/kg camelina oil when macronutrient allocation was used. The global warming potential was 15 g CO2 eq/MJ HVO, or 27 g CO2 eq/MJ HVO when soil organic carbon effects were not included, representing an 84% and 71% reduction, respectively, compared with fossil fuels.