Optimal Configuration of Energy Storage in Off-grid Micro Grid with Practical Principle

With the environmental advantages of solar energy in Lhasa area, the use of solar photovoltaic (PV) in residential power generation is encouraged by China governments incentives, however, what number of battery for energy storage from installing an off-grid PV system under given load profile is not clearly understood yet. This study aims to investigate the economic and technical performance of residential PV system and find the optimal size of battery. The proposed PV system composed of PV arrays, diesel generator and energy storage system (ESS) is established and simulated by means of HOMER (Hybrid Optimization of Multiple Electric Renewables) software. Date of technology parameters, cost parameters and available resource have been used to find the optimal system configuration with the lowest net present cost (NPC). Finally, the optimal sizing of energy storage, state of charge (SOC) for energy storage, the cost of each part and power generation cost under the optimal configuration of this system have been analyzed. The simulation results show this renewable resource can deal with 69% of the annual total electricity production with storage capacity of 416.4 kWh.