Environmental impact assessment of biodiesel production from soybean

Abstract

In this study the environmental impacts of biodiesel production from soybean were determined by using life cycle assessment (LCA) methodology. In order to achieve this objective all four LCA stages (goal setting, life cycle inventory, impact assessment and interpretation) were followed. The system boundaries included: cultivation, transport, crushing and extraction, soy oil refining and biodiesel production. The functional unit considered in this study is 1000 kg of biodiesel. All the inputs and outputs for each process included in the biodiesel production system were collected, calculated and estimated in the inventory phase. Environmental impact assessment step was performed considering LCA methods such as: CML 2001, CML 96, EDIP 2003 and ReCiPe. The impact categories selected for this evaluation were: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), human toxicity potential (HTP), photochemical ozone creation potential (POCP), agricultural land occupation (ALO); climate change ecosystems (CCE); climate change human health (CCHh); fossil depletion (FD); particulate matter formation (PMF) etc. Results showed that negative values were obtained for GWP, EP, CCE, CCHh indicators which means positive impacts of biodiesel production on the environment while the others impact categories have positive low levels respectively negative environmental impacts. Overall the greenhouse gases (GHG) are emitted from combustion of fuel used; the diesel used for soybean transportation also contributes to GHG emissions; the transesterification process significantly contributes to the emissions of these gases.