Abstract Switzerland has voted for a gradual nuclear phase-out, starting in 2019 with the decommissioning of a first nuclear reactor; however, there is still a debate about how the country will replace nuclear generation. Electricity markets are transitioning towards renewable sources such as hydro, wind and solar. The latter two could produce a mismatch between demand and supply. Combining renewables with storage is one way to address this challenge. This paper analyzes the feasibility of 100% renewable generation in Switzerland. We consider hydro and PV generation, combined with pumped hydro storage, to address the timing problem between demand and PV generation. We explore several combinations of installed solar capacity, reservoir levels and pumping capacity. Our findings indicate that given current technological development, Switzerland would need to double its pumping capacity, increase solar generation capacity by a factor between 13 and 25, while increasing reservoir size up to 100% depending on the installed solar capacity.