Pongamia Biodiesel Production Potential in Vanua Levu: A Full LCA of Emissions Reduction

Abstract

Biofuels are becoming increasingly popular as alternative fuels for transport due to rising oil prices and the need for energy security in the Pacific Island Countries (PICs). Indigenous production of biodiesel from second generation feedstock has the potential to reduce the dependence on costly diesel fuel imports and minimize Greenhouse Gas (GHG) emissions while avoiding the food versus fuel controversy associated with first generation biodiesel. Biodiesel production from Pongamia oil has been receiving increasing attention recently, as the oil is inedible and the trees have the ability to survive on many types of soils, including marginal lands. Vanua Levu is the second largest island of Fiji and has significant land resources available for agriculture, from which approximately 58,897 ha of marginal land can be made available for establishing Pongamia plantations. Using the entire available land resource, the production of 488,834,780.40 L of Pongamia oil per annum has been projected. While Pongamia oil can be produced domestically and converted to a nominally carbon-neutral Pongamia biodiesel, the life cycle production of such fuels entails emissions to the environment due to the use of fossil fuels and other GHG-producing agents. In this work the environment impacts of these GHG emissions were assessed via Life Cycle Assessment (LCA) in terms of Global Warming Potentials (GWPs), Acidification Potentials (APs) and Eutrophication Potentials (EPs) in air. The Pongamia biodiesel system shows a net Carbon Dioxide (CO2) emission of 18.32 g CO2eq/MJ, which is five times lower in comparison with diesel production system that shows a net CO2 emission of 98.03 g CO2eq/MJ. The blends of B5, B10, B15, B20 and B100 show 4.07%, 8.13%, 12.20%, 16.26% and 81.31% reduction in CO2 emissions, respectively, in comparison with diesel. Moreover, the net Sulphur Dioxide (SO2) emission in Pongamia biodiesel system is 0.056 g SO2eq/MJ, which makes relatively low contributions towards the Acidifation Potential (AP) and Eutrophication Potential (EP) of the air. The indigenous production of Pongamia biodiesel shows total possible avoided emissions of approximately 3,202,733.49 kg CO2eq if diesel fuel is replaced by Pongamia biodiesel produced from the 154 ha of existing Pongamia farms. The reduced emissions of such GHGs indicates that Pongamia biodiesel is a suitable alternative for diesel fuel in outer and remote islands of developing countries in the PICs for operating inter-island shipping vessels, fishing boats and small diesel power plants for household electrification.