Optimization of self-consumption and techno-economic analysis of PV-battery systems in commercial applications

Highlights: • Optimization of self-consumption and the degree of self-sufficiency in commercial applications. • Technical and economic analyses for a PV-battery system. • Sensitivity analysis considering different sizes and prices of PV and battery systems. • Investigation of batteries to increase self-consumption today is not economic in the considered applications. - Abstract: Increasing costs of electricity supply from the local grid, the decreasing photovoltaic (PV) technology costs and the decreasing PV feed-in-tariff according to the current German Renewable Energy Sources Act (EEG) will in the future raise the monetary incentives to increase the self-consumption of PV energy. This is of great interest in commercial buildings as there mostly is sufficient place to install high capacities of photovoltaic panels on their own roofs. Furthermore, the electricity purchase price from the local grid for commercial consumers nowadays is about 20 €ct/kW h, which is higher than the cost of generation of electricity from solar panels (about 8–12 €ct/kW h). Additionally, the load profiles in commercial applications have a high correlation with the generated solar energy. Hence, there is a great opportunity for economic savings. This paper presents optimization results with respect to self-consumption and degree of self-sufficiency for a supermarket in Aachen, Germany. The optimization is achieved using real measurement data of load profile and solar radiation. Besides, techno-economic analyses and sensitivity analyses have been carried out to demonstrate the influence of different PV system sizes, PV system costs and interest rates. Moreover, to raise self-consumption different battery sizes with different battery system costs have been investigated and analysed for 2015 and 2025 scenarios as well. The results show that the installation of a PV system can reduce the electricity costs through self-consumption of self-generated PV energy. Also, applying battery energy storages in combination with PV systems can reduce the electricity costs even more, assuming that the battery costs can be reduced down to 200 €/kW h in the future.