Emergy Assessment of Biodiesel from Conventional, Organic, and Agroecological Soybean

This paper presents emergy assessment of biodiesel production in Brazil using conventional, organic and agroecological grown soybean. For the conventional soybean biodiesel the indicators are: Transformity: 5.05E+05 seJ J; Renewability: 24.1%; Emergy yield ratio: 1.40; Environmental loading ratio: 3.15. These values indicate high demand of non renewable resources and low sustainability degree, it is because the crop production and its industrial conversion are supported by non-renewable resources s chemicals, goods, and process energy. It also reinforces global warming due to direct and indirect fossil fuel use, soil oxidation, waste treatment, substitution of forest area by agriculture, etc. Negative externalities account for 12.7% of the biodiesel produced from conventional soybean transformity. The biodiesel from organic soybean (small scale, family managed) present better indicators: Transformity: 4.25E+05 seJ J; Renewability: 36.4%; Emergy yield ratio: 1.63; Environmental loading ratio: 1.74. Negative externalities accounted for only 2.2% of the transformity value in this case. The biodiesel from agroecological soybean production (small scale, family managed, ecological principles) present the better indicators: Transformity: 3.09E+05 seJ J; Renewability: 49.5%; Emergy yield ratio: 1.92; Environmental loading ratio: 1.02. These results showed that biodiesel produced from organic and agroecological soybean are better alternatives for energy supply. However, the biofuel production policy implemented in Brazil supports the conventional energy intensive system and, as result, the large scale monoculture farms are stimulated to reproduce and substitute traditional food production farming. Therefore, it is possible to observe that Brazilian biodiesel production policy moved to the opposite direction of their original objectives: clustering biodiesel production with more sustainable systems of vegetable oil production (lower scale, ecological mode of production and more working places).