Progress in the sustainability assessment of bio-ethanol production

Considering our experience in the study of first-generation ethanol production from sugarcane in two modalities in Mexico, one from molasses and the other from direct juice, we compared the sustainability level of each modality in order to find the modality with the highest sustainability. We developed a sustainability index integrated by six indicators applied in all the lifecycle stages of each crop modality, considering: greenhouse gas emissions (GHG), land use, water use, energy balance, ethanol production costs and the number of employments generated. Our research shows the production of sugarcane ethanol from direct juice has the highest sustainability index; therefore, it is the most sustainable modality. With the purpose to build a more powerful tool, and to expand it to other energy crops, we are assessing the need to increase the number of indicators up to twenty and to build a sustainability index applying a multi-criteria evaluation to estimate weight factors.