Why Switzerland Says Yes to New Nuclear Power Plants

Seven claims, fact-checked

The report finds that the No campaign rarely uses false figures but regularly uses incomplete ones. Each chapter quotes the campaign, then sets the claim against the full evidence.

1. “A parliamentary decision against the will of the people.” Of the three votes the campaign cites, only the 2017 Energy Strategy vote concerned nuclear power. Recent polling shows 56% support for lifting the ban, and 79% support continued operation of the existing plants.
2. “Nuclear power makes Switzerland dependent on foreign countries.” Uranium supply is diverse; Russia ranks sixth in mining. The real dependence was on enrichment, where Western suppliers have been rebuilding capacity since 2022.
3. “The Swiss way with solar, wind and hydropower is already a success.” Switzerland already relies on winter imports, and the electricity industry’s own 2050 scenarios count on imports and gas-fired plants. The country has about 50 wind turbines.
4. “Nuclear waste is an unsolved problem.” Nagra applied in 2024 for a deep geological repository at Nördlich Lägern, in Opalinus Clay. The site has geological room for waste from new plants, subject to a further approval.
5. “Nuclear energy is too expensive.” BAK Economics puts a new EPR-1600 at about CHF 17.25 billion, against the CHF 25 billion the campaign cites, with CHF 1.6 billion a year in value added and about 2,900 jobs.
6. “Nuclear energy is too dangerous.” The probability of a severe accident at a Generation 3+ reactor is about 100 times lower than for the current Swiss fleet. Per TWh, nuclear causes about 0.03 deaths, comparable to solar and wind.
7. “Switzerland can reach net zero by 2050 just as easily without nuclear.” The ETH/PSI study behind the claim still requires 5.4–12.4 TWh of winter imports in 2050, and relies on hydropower that the 2026 drought showed to be exposed to climate change.

What happens when Swiss nuclear goes offline

The Anthropocene Institute analysed Swissgrid and Energy-Charts data in two ways: an hour-by-hour regression of nuclear availability against cross-border flows from 2021 to 2025, and two test cases, the scheduled overhauls at Leibstadt in 2021 and Gösgen in 2025.

When 1 GW of Swiss nuclear capacity goes offline, the cross-border balance shifts by about 853 MW, through more imports or fewer exports. Almost the entire shortfall is balanced across the border rather than at home.

Reservoir hydropower was shifted in time, not added. During each outage about 2.13–2.16 TWh of hydro generation was brought forward, and almost all of it was paid back from normal operation in the following months. Balancing the two outages took about 4.79 TWh and 4.58 TWh of additional generation in Germany, France, Italy and Austria.

What the report concludes

In 2025 about 3.6 TWh of Swiss generation came from thermal plants. A single 1.2 GW reactor at 90% availability would generate about 9.5 TWh a year. Running alongside existing hydropower, it would cover the four peak hours of each day even under a deliberately strict stress test. The authors recommend a robust path under uncertainty, one that keeps nuclear energy among the options. A Yes vote builds no plant; it keeps open the possibility of building one.

What the report covers

• The seven claims of the “Nein zu neuen AKW” campaign, each with sources.
• Uranium mining, conversion and enrichment, and Axpo’s fuel contracts since 2022.
• Support costs per MWh for new nuclear and alpine solar.
• Accident risk, deaths per TWh, and dam safety as a comparison.
• Hourly grid analysis of the Leibstadt 2021 and Gösgen 2025 outages.
• Heat from nuclear, including Beznau’s district heating network.