Hydropower plays a major role in Switzerland's electricity production, accounting for approximately 55-60% of the total production. The production fluctuates annually, depending on the amount of precipitation and other climatic factors. As part of the Energy Strategy 2050, hydropower is to be expanded to produce at least 2 TWh additional electricity per year.

A distinction is made between the following types of hydroelectric power plants:

• run-of-river power plants on rivers (not controllable, usable year-round for base load)
• storage power plants on reservoirs (controllable, usable year-round but particularly interesting for peak and winter electricity)
• Pumped-storage power plants with reservoirs and compensating reservoirs and pumps (controllable, but with energy loss; usable year-round but particularly for peak and winter electricity, utilization of electricity market price differences)

Due to the already implemented and planned expansion of photovoltaic production, which contributes proportionately less to electricity production in the winter months than in the other seasons, and the gradual shutdown of nuclear power plants in Switzerland, it has become necessary to expand hydropower as a whole, but in particular controllable storage and pumped storage power plants. Together with wind power (higher production in winter) and photovoltaics (lower production in winter), electricity production should be guaranteed in the winter months. By shifting production to the winter months, summer electricity production has to be reduced in a number of projects in order to store water in reservoirs so that it can be turbined more in the winter months. Because this results in a loss of summer electricity production, and thus in less leeway for energy companies to meet peak electricity demand throughout the year, electricity consumers have to pay extra for the so-called “winter electricity reserve” via the “grid usage fee”.

In order to take into account the various interest groups regarding the expansion of hydropower and thus to broaden the consensus, Federal Councillor Simonetta Sommaruga convened the so-called “Round Table on Hydropower” in 2020, in which 15 priority expansion projects were identified that together are expected to contribute approximately 2 TWh of additional electricity production per year. These include expansions to existing reservoirs, additional tunnels and water catchments, as well as completely new dams and hydroelectric power plants. At the last minute, a 16th project, “Chlus (Küblis – Trimmis)” in the canton of Graubünden, was added to the list before it was approved by the referendum on June 9, 2024 as part of the federal law (“umbrella decree” (Mantelerlass)) for a “secure electricity supply with renewable energies”.

The map “Hydropower plants planned (Energy Strategy 2050)” shows the 16 projects of the “Round Table Hydropower” and other additional projects (“32 list”) that are currently being discussed. Information on the estimated additional annual production, storage capacities, economic efficiency, environmental impact and planning status is displayed and can be queried. Projects that are at an advanced planning stage show more information and technical details than projects about which little is yet known. If the information has already been published as part of the concession and approval procedures, the map shows the elevated dams, extended reservoir perimeters, power plant locations, water intakes, tunnels and feeder pipes, compensating reservoirs and residual water sections.

Important note: these are “projects” whose implementation plans are at various stages of development and whose approval procedures are still ongoing or have not even started. In addition, economic considerations and subsidies play a major role in whether a power plant project is actually implemented. For some projects, the technical feasibility is first clarified. In the case of doubly curved arch dams, raising an existing dam that has been statically calculated for a specific water pressure, topography and rock composition is technically very demanding. See the referenced Infosperber article. The high technical effort required to raise an existing dam can make such projects uneconomical.