Greenhouse gas footprint of biodiesel production from used cooking oils

Abstract

The methodology used in the EU Renewable Energy Directive to assign default values to biofuel greenhouse gas emissions and reduction potentials has its shortcomings. These undermine its practical application in estimating actual values. This thesis proposes a more realistic greenhouse gas footprint of biodiesel based on used cooking oils. This greenhouse gas footprint of used cooking oil sourced hydrotreated vegetable oil has been calculated using an attributional life cycle assessment. Through a market analysis it is shown that hydrotreated vegetable oil production in the Netherlands is increasing due to its favourable attributes when compared to alternatives such as FAME. As a consequence of increasing policy pressure regarding waste based biofuels, used cooking oil has become a major feedstock for biodiesel production. Further analysis showed that used cooking oil demand in the Netherlands is higher than the available supply which leads to increased imports the feedstock from overseas origins. The main finding of this thesis is that the greenhouse gas footprint of used cooking oil based biodiesel depends on the origin of the feedstock and the subsequent transportation mode. Bulk shipping of used cooking oil using chemical tankers is a worse option than using flexitanks, with regards to greenhouse gas emissions. Likewise, used cooking oil imports from China show higher greenhouse gas emissions than US imports. But both options show inferior performance when compared to domestic and intra-EU used cooking oil collection, with the latter being the cleanest choice. The range of GHG emissions associated with UCO-transportation for hydrotreated vegetable oil production found in this thesis is 2.19 to 14.5 gCO2-eq/MJ NExBTL.