The hard choice for alternative biofuels to diesel in Brazil.

This paper selects biofuel scenarios to substitute diesel in Brazil based on oil reserves increase, diesel imports, CO(2) emissions, crops agronomic yields, byproducts marketing and social impacts. This hard task still considers that agricultural practices in developing countries have large social impacts. Brazil presents high consumption of diesel oil in transport; low agronomic yield of traditional vegetable oil crops, which demand large cultivation areas contrasting with microalgae and palm oils which present high productivity. Concerning technologies, thermal cracking and transesterification of vegetable oils present a difficult economic situation related to vegetable oils price, food competition and glycerin market; BTL technology, meaning thermal gasification of biomass to liquids, faces problems related to low density of biomaterials and low viscosity of synthetic biodiesel produced. Biorefinery algal integrated systems and co-solvent technology to introduce up to 8% of ethanol into diesel seem to be feasible routes to reduce diesel consumption.