Transitions in biofuel technologies: An appraisal of the social impacts of cellulosic ethanol using the Delphi method

The sustainability of biofuels produced from food crops has become a focus of public and scientific scrutiny in the past few years. In the case of ethanol production, advanced technologies aim at avoiding controversy by using instead cellulosic biomass contained in wastes, residues and dedicated energy crops. However, despite the positive expectations that drive the development of the so-called "cellulosic" ethanol, sustainability challenges remain to be elucidated. Expecting to contribute to closing the gap in the field of the social assessment of biofuels, this paper reports and analyses the results of a Delphi survey that explored the perception of biofuel experts from different countries on potential social impacts of cellulosic ethanol. The complexity of appraising impacts emerges as one important conclusion of the study along with the realisation that these will be context-specific. Except for the case of municipal solid waste used as feedstock, such a technological transition might not be able to ameliorate the issues already faced by conventional ethanol, especially when production is based in poorer countries. This is because impacts of cellulosic ethanol depend upon both the technical dimension of its production and the socio-political context of locations where production might take place.