Biodiesel from Waste Cooking Oils in Portugal: Alternative Collection Systems

Abstract

Waste Cooking Oils (WCO) have been gaining prominence as an alternative feedstock for biodiesel production due to is potential to reduce the economic and environmental costs of biodiesel produced with biomass. However, there are various types of WCO collection with different collection efficiency and environmental impacts. The aim of this paper is to present an environmental assessment of biodiesel from WCO addressing different collection schemes in Portugal. The implications of alternative allocation approaches (no allocation, mass allocation, energy allocation and economic allocation) in the final results are also assessed. Life Cycle Impact Assessment was calculated (ReCiPe method) for: Climate Change; Terrestrial Acidification; Marine Eutrophication and Freshwater Eutrophication. WCO collection contribution for the overall impacts ranged significantly for the various collection system and impact categories. The application of different allocation approaches led to differences in the results up to 11 %. A comparison between the GHG emissions calculated for biodiesel from WCO and the typical and default values presented in the Renewable Energy Directive was performed. The GHG emission saving for biodiesel from WCO collected in Portugal ranged from 81 to 89 %.