Influence of different battery charging strategies on residual grid power flows and self-consumption rates at regional scale

Abstract Battery storage systems can help to integrate excess Photovoltaic (PV) energy into the local energy systems but also increase the request for higher self-consumption rates of the households. This study uses a spatially resolved approach with hourly time steps to analyze the influence of batteries on the domestic residual loads on a regional scale. A domestic energy component is developed consisting of a PV-system model, the demand component, and a battery storage device. The study area is located in the south of Bavaria and 4906 households with PV-systems between 3 and 10 kWp power were selected assuming a battery capacity of 6.2 kWh in average. Three charging strategies for domestic battery storage systems are assessed: (1) Maximization of self-consumption, (2) Fixed feed-in limit of 70% of the PV-peak power, and (3) Daily dynamic feed-in limit based on ideal forecasts. The best result is obtained through the third strategy with a self-consumption of 78.5% on average and the highest reduction of the grid flows by 20% by damping grid excesses. The influence of the charging strategy rises with increasing size of PV- and battery storage systems and therefore residual loads. Regional variations are further caused by the meteorological conditions, different PV- and battery sizes and parameters and demand profiles on municipal scale. Consequently, a sufficient sample size with different set-ups is recommended for a full evaluation of battery charging strategies.