Life cycle assessment of hydrotreated vegetable oil from rape, oil palm and Jatropha

A life cycle assessment of hydrotreated vegetable oil (HVO) biofuel was performed. The study wascommissioned by Volvo Technology Corporation and Volvo Penta Corporation as part of an effort to gaina better understanding of the environmental impact of potential future biobased liquid fuels for cars andtrucks. The life cycle includes production of vegetable oil from rape, oil palm or Jatropha, transport of theoil to the production site, production of the HVO from the oil, and combustion of the HVO. The functionalunit of the study is 1 kWh energy out from the engine of a heavy-duty truck and the environmentalimpact categories that are considered are global warming potential (GWP), acidification potential (AP),eutrophication potential (EP) and embedded fossil production energy. System expansion was used totake into account byproducts from activities in the systems; this choice was made partly to make thisstudy comparable to results reported by other studies. The results show that HVO produced from palmoil combined with energy production from biogas produced from the palm oil mill effluent has thelowest environmental impact of the feedstocks investigated in this report. HVO has a significantly lowerlife cycle GWP than conventional diesel oil for all feedstocks investigated, and a GWP that is comparableto results for e.g. rape methyl ester reported in the literature. The results show that emissions from soilcaused by microbial activities and leakage are the largest contributors to most environmental impactcategories, which is supported also by other studies. Nitrous oxide emissions from soil account for morethan half of the GWP of HVO. Nitrogen oxides and ammonia emissions from soil cause almost all of thelife cycle EP of HVO and contribute significantly to the AP as well. The embedded fossil production energywas shown to be similar to results for e.g. rape methyl ester from other studies. A sensitivity analysisshows that variations in crop yield and in nitrous oxide emissions from microbial activities in soil cancause significant changes to the results