Techno-economic analysis of off-grid hybrid renewable energy system for Sri Lanka

Off grid hybrid renewable energy based power systems for rural electrification has become an attractive solution for areas where grid electricity is not feasible. Hybrid systems use several generation technologies, therefore the selection of proper technologies and optimum sizing of the components has become of great importance in reducing the overall cost and increasing the reliability of the service. The focus of this study has been to investigate the optimum configuration of a hybrid system which can supply electricity to a rural community in Sri Lanka. A rural village from the Siyambalanduwa region in Sri Lanka inhabiting approximately 150 households resulting approximate daily electricity demand of 270 kWh has been studied. Several electricity generating technologies including solar, wind and diesel gen sets have been studied and the total net present cost of each system configuration has been calculated for 20 years of lifetime of system to examine the lowest energy cost option. It has been found that the combination of wind turbines, PV system, a battery bank and a diesel generator creates the optimum hybrid system following the rated capacities, wind - 40 kW, PV - 30 kW, battery bank - 222 kWh and the diesel generator - 25 kW. This system can supply electricity at an approximate levelized cost of 0.3$/kWh.