Modeling and evaluation of combined photovoltaic-battery systems in the decentralized german power generation

This paper presents the overall economic evaluation of a battery storage in a decentralized energy supply system by means of mathematical optimization methods. The energy supply system, consisting of a battery storage in combination with a photovoltaic system as well as a heat pump with a heat storage and a conventional gas boiler, will be evaluated with regard to technical and economic criteria. The aim of the optimization is to identify the optimal structural dimensioning and the optimal operating mode of each component in the system to cover the energy consumption with connection to the public electricity grid. Based on exemplary studies for a German state it can be seen that photovoltaic systems nowadays operate economically. However, the use of a battery storage system is not optimal in economic terms. The reduction of the investment costs shows that the use of a battery storage system can prove advantageous in the future. In connection with a time variable electricity tariff it can be seen that this has an increasing effect on the optimal capacity of the battery. On the whole the use of a combined photovoltaic-battery system can improve own benefit and consumption towards the use of a single photovoltaic system without a storage option.