COST-BENEFIT ANALYSIS OF FIRST- AND SECOND-GENERATION BIOFUELS BASED ON AN ECONOMIC VALUATION OF LIFE-CYCLE IMPACTS

摘要

In the face of the current push for liquid biofuels worldwide, the design of policies compatible withrnsustainable development requires a careful and comprehensive analysis of their respective benefits and drawbacks.rnThe environmental impacts of biofuels are usually quantified with life-cycle assessment (LCA), which providesrnindicators for a suitable range of impacts but leaves their prioritization up to decision-makers. Cost-benefit analysisrn(CBA) may be used to aggregate these impacts through an economic valuation of positive and negative effects on thernenvironment. Here, we propose a simplified and ad hoc framework to combine LCA with CBA based on differentrnvaluations found in the literature, and apply it to a case-study comparing first- and second-generation biofuels in thernPicardy region (northern France). The results were compared to 2 other methods already used to monetizernexternalities: the Eco-Cost method, and a method developed as part of the European Nitrogen Assessment. In terms ofrnLCA, 2G bioethanol from miscanthus emitted 30 to 90% less pollutants than its 1G counterpart from sugar-beet, duernto its lower requirements in agricultural inputs. This was directly reflected in the ad hoc CBA results, with a 3 to 6-rnfold decrease between the external costs of sugar-beet and miscanthus ethanol for the 4 impact categories monetized.rnThere was a large variation between the valuation methods, which varied within an order of magnitude. For instance,rnthe eutrophication costs associated with sugar-beet ethanol varied from 4 10~(-4) to 4 10~(-3) €/MJ of biofuel. Compared tornfossil fuels, miscanthus-based ethanol incurred an overall net positive externality of 0.1€/MJ of biofuel, which is on arnpar with the tax exemption level put in place by the French government for 2nd generation biofuels.