Energy systems of many European countries are undergoing transition. Although Switzerland’s electric energy system is in a favourable situation and is not dependent on fossil fuels thanks to its large share of renewable hydroenergy and nuclear energy, it too will face a challenge when the existing nuclear generators will be phased out. Large scale energy storage, potentially in the form of hydrogen, will become an essential element of future energy systems. This paper describes the relevance of hydrogen economy in the context of European Union’s and Switzerland’s energy and climate policies and explores the current developments in the area of conversion of hydrogen back to electric energy, with special emphasis on gas turbines. In a case study, work of the Swiss electric energy system is simulated under various assumptions about electric energy supply and availability of energy storage in the form of hydrogen. In the case of nuclear energy phase-out and increased solar power capacity, up to 10 TWh of hydrogen storage capacity would be needed to fully shift the summer surplus into winter, but ~2.5 TWh would be enough to meet the energy import limit set in the Swiss energy strategy.