As decarbonization progresses, the Swiss and European energy systems are transforming, with a growing need for flexibility to balance supply and demand due to the expansion of variable renewable energy sources like photovoltaics and wind power. This shift is further complicated by the increasing electrification of heating and transport, which places additional strain on the grid but also offers opportunities for demand-side flexibility.

Ensuring system stability, security of supply, and cost efficiency requires flexibility across timescales—from seconds to seasons—enabled by technologies like demand-side management, sector coupling, dispatchable generation, and energy storage. To assess storage needs, integrated energy system modeling that captures electricity and heat sectors, as well as operational and investment decisions, is essential.

Relevant storage technologies include hydropower, batteries, power-to-X solutions, building-integrated and large-scale thermal storage, industrial high-temperature storage, and gas or liquid storage, depending on whether fuels are imported or produced locally.

The study examines the need and role of energy storage in Switzerland for the years 2035 and 2050, aiming to analyze their contribution to the flexibility, stability, and security of the energy system. It considers various types of storage—electricity, heat, and gas/liquid storage—and evaluates their use across different timescales (from sub-hourly to seasonal). The focus is on optimizing the provision of electricity and heat, taking into account traditional generation technologies such as solar, wind, hydro, gas, hydrogen, and climate-neutral fuels. The storage requirements are determined through various use cases and depicted across different timeframes.