Grid-Connected Solar PV Plant Surplus Energy Utilization Using Battery Energy Storage System

This paper aims to develop a charge & discharge controller for 700kWh/540kW Battery Energy Storage System (BESS) with and its integration with Grid-connected 3MWp Solar PV Plant. The BESS plays its very important role to store surplus solar PV power and to perform functions such as load shifting for the economic benefits of electricity consumers. The BESS Charge Discharge Control Strategy serves the purpose to allow battery charging operation when surplus PV power presents after supplying to the load demand and consistently charging during off-peak hours with lower electricity cost compared of peak hours. Similarly, the control system operates discharging operation when PV power does not meet the load demand while being within the peak hours defined by the electricity provider. The integration of functions of load Shifting of the BESS, together with the Solar PV plant will be able to reduce the campus load consumption from the power grid significantly while being cost-effective. The obtained results based on the proposed control strategy demonstrate that minimum energy cost can be saved from this BESS is $ 14.25/day regardless any weather conditions, $ 81.12/day during high variability day, and $ 53.41/day during clear sky day; with the constraints of not considering maximum demand cost and fit-in tariff.