Interdependencies of Home Energy Storage between Electric Vehicle and Stationary Battery

Decentralized power generation in private homes, especially by photovoltaic systems, is already common in Germany. The developments of batteries, both for electric vehicles (EV) and for stationary storage might lead to a mass market for those batteries. In this paper we evaluate the economy of stationary battery storage with photovoltaic system at home in the context of available EV and its integration level into the home. Therefore, we use an optimization model with one year detailed operation planning and maximize the net present value of the storage investment. We integrate restriction functions for the technical parameters of the storage systems and limit EV availability and usage on the basis of German mobility studies for single vehicles. The results show, that an investment in a stationary battery system in combination with a photovoltaic system is profitable in Germany under the assumptions considered. The observed high numbers of battery cycles lead to strong requirements for battery lifetime, i. e. cycle stability and long calendar life time. Therewith, Li-ion batteries are a promising technology. In combination with an EV, the net present value of the stationary battery system is smaller when the EV is integrated into the home by controlled charging or the vehicle to home (V2H) concept, which allows discharging into the home system. The size of the EV battery, the availability at daytime and the load curve of the home are the main influencing factors for the profitability of the battery system.