Life-cycle assessment of bioenergy production systems from oilseed rape crops

摘要

This article is concerned with a life-cycle assessment (LCA) study of bioenergy production systems based on oilseed rape cultivation. In particular, the study compares the production of biodiesel via transesterification of rapeseed oil, power generation through diesel engines fuelled by raw vegetable oil, and power generation through steam power plants fuelled by the overall aboveground biomass. The results of the LCA study show that bioenergy systems based on power generation perform better than bioenergy systems based on biodiesel production. In particular, the best energy and environmental performance are achieved with steam power plants fuelled by the overall aboveground biomass, which allow a reduction of primary energy consumption by about 75 per cent, the greenhouse impact by about 60 per cent, and the acidification impact by about 52 per cent with respect to conventional power generation plants. A favourable energy and environmental profile can also be achieved by diesel power systems (DPSs) and biodiesel fuel systems (BFSs), especially if the straw is used for power generation. In particular, the primary energy saving is about 58 per cent for DPSs and 72 per cent for BFSs without any straw energy use and about 67 per cent and 74 per cent with straw energy use, respectively. Moreover, these systems allow a reduction of the greenhouse (by about 55–58 per cent) and acidification impacts (from 21 per cent to 38 per cent), except for the BFS without any straw energy use, which increases the acidification impact by about 42 per cent. The study also demonstrates that crop cultivation greatly affects the performance, owing to the use of fuels and fertilizers.