Integration of photovoltaics (PV) in the power system is strongly driven by decreasing prices for modules and incentive programs of different governments and is therefore expected to continue at similar rates in the future. Due to the mismatch between solar electricity generation and demand a secure supply of electricity is only possible with other integrated support components responsible for a temporal shift of the energy like storage systems, which will then also reduce the strain on transfer infrastructure. From a European perspective, it is beneficial to reach a mix of PV and other technologies, like wind generation, which show different characteristics in the annual generation profile. The whole European power system benefits from the smoothing effects which result from aggregation of different regions in the total availability of power. In this work an evolutionary optimisation implemented in the GENESYS tool is used to estimate the optimal allocation of PV and wind turbines (WT) in a European electricity system with focus on the resulting storage demand. Cross national transfer capacities and different storage options represent additional flexibility to the system to balance temporal and spatial energy demand. While higher shares of PV require a higher amount of short-term storage options, a higher share of wind turbines requires greater transfer capacities over long-distances.