Assessment of energy sustainability and carbon footprint of a Jatropha-biofuel chain in rural area of Brazil

Because of the world population growth and increasing energy demands, renewable energy sources are seen as valid fossil fuel alternatives that could guarantee environmental benefits. In this context Jatropha curcas L. has been identified as a promising feedstock for biofuel production and promoted as a sustainable biofuel crop. This paper analyzes the creation of a Jatropha-oil chain in a rural area in north-eastern Brazil (Ceará State) utilizing the Life Cycle Assessment (LCA) method. The aim of this study is to evaluate the energy sustainability expressed as cumulative energy demand (CED) and carbon footprint expressed as global warming potential (GWP) of a Jatropha-oil chain in comparison with fossil fuel (diesel). The component with most impact on the Jatropha-oil chain was electricity consumption, which accounted for 42% and 63% of CED and GWP, respectively. The analyzed Jatropha biofuel-chain presented a more favourable energy balance (94% of CED saved) and a lower effect on global warming (77% of greenhouse gas emission, GHG, avoided) in comparison with diesel fossil fuel. If the biofuel produced, instead of being used locally, was exported over a long distance (i.e. to the European Union), the energy and environmental benefits obtained were completely nullified. Crop management practices based essentially on manual labour of family farming system, as in the present study, determined a positive influence on the energy balance and carbon footprint in the Jatropha-oil chain. On the contrary, a crop management practices making high use of inputs (fertilizers, pesticides, irrigation ...) on large areas of monoculture, could negatively affect the socio-economic sustainability of the whole Jatropha-biofuel chain.