Life cycle impact assessment of biodiesel using the ReCiPe method

Abstract

This paper presents the life cycle impact assessment (LCIA) results of biodiesel produced from rapeseed oil. The functional unit (FU) is defined as 3750 km of distance traveled by a truck fuelled with biodiesel. The reference flow is 1000 kg of biodiesel. The LCIA method used in the study is the ReCiPe method. At midpoint level the ReCiPe method addresses environmental issues within 18 impact categories. Most of these midpoint impact categories are further converted and aggregated into 3 endpoint categories (damage to human health, damage to ecosystem diversity, damage to mineral resource availability). The total impact of biodiesel’s life cycle was estimated at 540 Pt/FU. The damage to ecosystem diversity (1.48E-04 species•year/FU), the damage to human health (7.48E-03 DALY/FU) and the damage to mineral resource availability (8.11E+03 US$/FU) are responsible for 63%, 27% and 10% of the total negative impact in the life cycle of biodiesel, respectively. The results have revealed that only 4 impact categories are responsible for most of the impacts within the specific endpoint categories. These are impacts associated with global warming (3000 kg CO2 ekv./FU), particulate matter formation (12.4 kg PM ekv./FU), agricultural land occupation (6710 m2a./FU) and fossil fuel depletion (21168 MJ/FU). Greenhouse gases emitted in the life cycle of biodiesel (mainly N2O, CO2) are responsibly for 56% of the damage caused to human health and for 16% of the damage caused to ecosystem diversity. Airborne emissions which contribute to particulate matter formation (NOx, NH3, PM, SO2) are responsible for 43% of the damage caused to human health. Agricultural land occupation is responsible for 82% of the damage caused to the ecosystem diversity. Damage to mineral resource availability is almost entirely related to the depletion of fossil energy sources. The production chain of biodiesel and the combustion of biodiesel are responsible for 69% and 31% of the total impact of biodiesel’s life cycle, respectively. The negative impact of the production chain is mainly related to biodiversity loss due to agricultural land occupation (38%) and the life cycle impacts of mineral fertilizers used in the production of rapeseed (47%). The environmental impact of biodiesel can be reduced by increasing the yield of rapeseed with more efficient use of fertilizers and optimization of agro-technical processes.

Keywords

• biodiesel
• rapeseed
• life cycle assessment
• ReCiPe method