Enseignements et limites de l’étude sur l’impact des biocarburants de première génération coordonnée par l’Ademe

CETIOM, Centre de Grignon, Avenue Lucien-Brétignières, 78850 Thiverval-Grignon, France

^* flenet@cetiom.fr

Abstract

In order to estimate the environmental impacts of first generation biofuels produced in France, a Life Cycle Assessment (LCA) was conducted in 2009 and published in the beginning of 2010. However, there have been discrepancies in the interpretation of the results of this study. The objective of the article was to present the results of this LCA and the uncertainties for rapeseed methyl ester (RME), in order to help people to understand the debates about the environmental impacts of biofuels. The four steps of the LCA (goal and scope definition, inventory analysis, impact assessment and interpretation) were presented in this article with a focus on the main uncertainties. This LCA confirmed the ability of RME to save non renewable energy (–65%) and greenhouse gas emissions (GHG, –59%). Hence according to these results, RME produced in France fulfils the GHG sustainable criterion of the European Directive on renewable energy (2009/28/EC). However, the sensitivity analyses of the LCA clearly showed that there were many uncertainties at the inventory analysis step of the LCA. The main uncertainty resulted from the effect of indirect Land Use Change (iLUC), which was not taken into account in this LCA, except in a sensitivity analysis in which a GHG emission due to deforestation (positive emission) or reforestation (negative emission) was added to the emissions of the LCA. This sensitivity analysis showed that the iLUC effect could not be neglected. This suggests that an accurate estimation of this effect is necessary. However, in order to properly take into account the iLUC effect on GHG, along with all the emissions due to biofuel production, a consequential approach is more relevant than the simple addition of an iLUC GHG emission as it was done in the sensitivity analysis.