Epsilon Open Archive

Abstract

Many life cycle assessment (LCA) studies have investigated the environmental impact of using biofuel in transportation compared with fossil fuels. Since these studies often use standard values for the fossil fuel reference scenario, there is a need for a thorough review of published data on fossil fuel use in transportation.

This study reviewed the available literature regarding greenhouse gas (GHG) emissions and energy balances in petrol and diesel use and examined possible causes for the differences reported in the literature. This included differences con-nected to the LCA methodology itself, but also those resulting from technical and economic effects.
Thirteen studies were reviewed in order to establish the level of GHG emissions and energy use in the well-to-tank perspective and, where possible, in the entire well-to-wheel perspective. The studies used different input data, allocation meth-ods and system boundaries, but the results fell within a narrow range, since the energy content of the fuels on a tank-to-wheel basis differed only slightly, while the use phase represents most GHG emissions and energy usage in fuel life cycles. All studies reviewed reported GHG emissions values that exceeded the reference value of 83.8 g CO2-eq/MJ fuel suggested in the EU Renewable Energy Directive of 2009.