Ethanol is the main biofuel produced and used today, representing almost 80 % of the total liquid biofuelsproduction and use worldwide. Sugarcane is now the second most used feedstock, behind corn, but it isthe one that presents the best performance in terms of GHG emissions reduction and land demand, and it is also a crop more adequate to developing countries production as it is cultivated already in more than 100 countries. The fast expansion of bioethanol in the recent past has brought to light several concerns about its sustainability and the discussions have been, mostly, in generic terms and with strong bias especially toward social aspects. It must be born in mind that biofuels are not equal and even the same biofuel, ethanol in our case, can present different sustainability characteristics depending on theproduction model and local conditions. By production mode we mean the feedstock agricultural pro uction system, the processing path and the socio-economic interfaces between ethanol producing enterprise and the local community.
To bring the ethanol sustainability discussions to a more scientific and objective level it is interesting to present the alternatives of production models in an organized way and to have sustainability indicators from the three dimensions (economic, social and environmental) to evaluate objectiively each one. We propose basically three models: High Technology Model (large scale, state of the art technology, verticalized production and processing, maximum efficiency and lowest cost), Medium Technology Model (mixed sugarcane production – independent grower and mill production, scale compatible with agriculture production, balance between profits and social benefits), Social Model (small independent sugarcane producers and outgrowers, integration with food production and energy services for the local community, jobs); a fourth alternative, the Balanced Model, would be the one optimized as a function of the local conditions, driving forces, government policies, local culture and practices, land tenure profile and existing infrastructure, trying to take advantage of the best characteristics of the three basic models.
A preliminary approach to evaluate the alternatives of production models is suggested and illustrated considering conditions observed for ethanol production from sugarcane in Latin America and Sub Saharan Africa.