Life cycle assessment of biodiesel production from pongamia oil in rural Karnataka

Pongamia pinnata is one of the promising tree species suitable for providing oil for biodiesel production. This paper addresses the life cycle energy balance, global warming potential and acidification potential, of a small scale biodiesel system, in rural Karnataka. In addition, the system has also been expanded to generation and use of biogas from seed cake for electricity production and evaluated for its environmental impacts. The environmental impacts have been benchmarked with the life cycle impacts of fossil diesel. The results show that non-renewable energy requirement of Pongamia biodiesel system is twenty-eight times lower than that of fossil diesel. A significant increase in global warming potential (GWP) is indicated in Pongamia biodiesel system compared to fossil diesel if wood is used as fuel. GWP would be seven times less if wood is not used as fuel. Acidification and eutrophication potential of Pongamia system was found to be nil. Further, expanding the Pongamia biodiesel system to include biogas production exploits the energy available in the system. It is also observed that one hectare of Pongamia plantation is capable of completely sequestering the CO2 released during the life cycle with additional sequestration potential up to 1 t CO2 ha-1. Moreover, the above aspects were significantly superior in Pongamia system when compared to Jatropha biodiesel system. Keywords: Biodiesel, global warming potential, acidification and eutrophication potential