Origins of the debate on the life-cycle greenhouse gas emissions and energy consumption of first-generation biofuels : A sensitivity analysis approach
Available results about energy and GreenHouse Gases (GHG) balances of biofuels from Life- Cycle Assessment (LCA) or life-cycle based studies present large discrepancies and thus, may lead to contradictory policy-making measures. This work reviewed seven important European LCA studies in a sensitivity analysis approach in order to get a better understanding of the roots of such a debate for three major biofuels in European production: rape methyl ester and ethanol from wheat and sugar beet. Global trends and variability of energy and GHG balances were depicted and completed with a sensitivity analysis carried out for each methodological and data parameter, which allowed making recommendations on the carrying out of LCA in a policy-making or a biofuels comparison context. Methodological choices, and especially allocation rule, appeared as key elements for results variation with influences on balances up to 149%; system expansion approach was identified as the most relevant rule since it integrates the market potential and the environmental interest of by-products promotion, which was pointed out as a crucial point for biofuels sustainability. The influence of local specificity for cultivation data was evaluated up to 167%, which puts too large geographical coverage in question. Modelling uncertainties due to N2O emissions from soils showed influences from 17 to 46%, which represents a crucial challenge for research and for LCA results accuracy. Approximations evaluation pointed out the need to integrate agricultural machinery into the assessment. Finally, land-use issue revealed its dramatic importance for LCA results and the need to define explicit scenarios for land-use alternatives.
| Main Authors: | , , |
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| Format: | article biblioteca |
| Language: | eng |
| Subjects: | P06 - Sources d'énergie renouvelable, P01 - Conservation de la nature et ressources foncières, P02 - Pollution, biocarburant, gaz à effet de serre, impact sur l'environnement, évaluation de l'impact, modélisation environnementale, ester, éthanol, Triticum, Brassica napus, Beta vulgaris, http://aims.fao.org/aos/agrovoc/c_27465, http://aims.fao.org/aos/agrovoc/c_34841, http://aims.fao.org/aos/agrovoc/c_24420, http://aims.fao.org/aos/agrovoc/c_37938, http://aims.fao.org/aos/agrovoc/c_9000056, http://aims.fao.org/aos/agrovoc/c_2671, http://aims.fao.org/aos/agrovoc/c_10677, http://aims.fao.org/aos/agrovoc/c_7950, http://aims.fao.org/aos/agrovoc/c_1066, http://aims.fao.org/aos/agrovoc/c_890, http://aims.fao.org/aos/agrovoc/c_2724, |
| Online Access: | http://agritrop.cirad.fr/563719/ http://agritrop.cirad.fr/563719/1/document_563719.pdf |
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