Biofuels

Biofuels are fuels made from non-fossil vegetal or animal materials (biomass). They belong to the renewable energy sources as they do not contribute to worsen some global environmental impacts, like the greenhouse effect, providing that their production is performed in efficient energy conditions with low fossil fuel consumption. This article presents: 1 - the usable raw materials: biomass-derived resources, qualitative and quantitative aspects, biomass uses; 2 - biofuels production from biomass: alcohols and ethers, vegetable oils and their esters, synthetic liquid or gaseous biofuels, biogas; 3 - characteristics of liquid biofuels and comparison with gasoline and diesel fuel; 4 - biofuel uses: alcohols and their esters, biofuels with oxygenated compounds; vegetable oils and their derivatives in diesel engines, biogas, example of global environmental impact: the greenhouse effect. (J.S.)