Denmark is currently on the verge of a transition to a fundamentally different power system where the share of renewable weather-driven power generation exceeds that of conventional sources. The excellent wind resources in the country are expected to fuel the transition to a renewable power system, but also solar PV may come to play a significant role in the fu- ture. Here, the impact of adding round-trip electricity storage to the Danish power system is analysed for all levels of wind and solar PV penetrations. In particular, a significant synergy between storage and an optimal mix of wind and solar PV has been identified.