Switzerland’s Federal Council has approved a report confirming that extending the lifespans of the Gösgen and Leibstadt NPPs up to 80 years is technically viable and economically profitable. This advances the country’s energy outlook well beyond the previously anticipated 60-year operational horizon.
The federal government report, released by the Swiss Federal Council (Bundesrat) earlier in May, was directly commissioned by a Senate postulate (parliamentary motion) to analyse the long-term energy policy and future electricity mix of Switzerland. It incorporates two key supporting studies conducted by external consultancies. Frontier Economics evaluated the economic profitability and market scenarios and Siempelkamp NIS assessed the technical feasibility and upgrade frameworks.
Upgrades are estimated to cost between 0.7bn and 1.2bn Swiss Francs $0.9-1.5bn) per plant, distributed over a 36-year timeline. The Federal Council explicitly noted that operators can absorb these upgrade costs independently without financial support from the state.
Swiss nuclear plants hold unlimited operating licences. They are legally permitted to run indefinitely, provided the operators prove to the Swiss Federal Nuclear Safety Inspectorate (ENSI – Eidgenössisches Nuklearsicherheitsinspektorat) that they fulfil all safety standards during major reviews every 10 years.
A definitive choice on whether to initiate these long-term extensions for the Gösgen plant must be finalised by 2029. This standard-setting pivot away from the post-Fukushima phase-out framework is driven by concerns over winter energy gaps and national climate goals.
Switzerland’s nuclear phase-out policy was legally imposed in January 2018, when the revised Nuclear Energy Act entered into force. The catalyst for this was the 2011 Fukushima Daiichi accident in Japan after which the government resolved to stop building replacement reactors. This set a course for a slow, gradual wind-down of Switzerland’s active nuclear energy production as the existing reactors reached the end of their safe lifespan. The policy was approved by referendum in 2017.
Switzerland’s policy shift happened in stages rather than a single moment, beginning with a major policy pivot in August 2024 and progressing into legislative rollbacks through 2025 and 2026. The reversal was triggered by a popular public initiative launched in early 2024 called “Electricity for all at all times (Stop Blackouts)”. The petition gathered 129,000 signatures, legally forcing the Swiss government to address the issue.
Rather than letting a public initiative rewrite the Swiss Constitution, the Federal Council chose to pre-emptively draft its own controlled legal counter-proposal to safely loop nuclear energy back into Switzerland’s long-term mix. Lawmakers have until August 2026 to finalise the legislative text. Because opponents have already promised a challenge, the final, binding reversal will likely be decided by Swiss citizens in a nationwide referendum scheduled for 2027.
Beyond life extensions, Switzerland’s upper house of parliament, the Council of States, recently voted to lift the blanket ban on building entirely new nuclear facilities. The Federal Council’s report even leaves open a framework for a new 1.6-gigawatt reactor by 2050 if renewable energy expansion struggles to meet rising domestic electrical demands.
Switzerland has three operational NPPs hosting a total of four reactors, providing 30-40% of the nation’s electricity. The Beznau plant comprises two 365 MWe pressurised water reactors (PWRs) commissioned in 1969 and 1971. The single-unit Gösgen NPP is a 1,010 MWe PWR commissioned in 1979. The single-unit Leibstadt NPP is a 1,233 MWe boiling water reactor (BWR) commissioned in 1984. Switzerland previously operated a fifth commercial reactor at Mühleberg (a 373 MWe, BWR) that closed in 2019 and is undergoing decommissioning.
The Federal Council’s report focused exclusively on Gösgen and Leibstadt due to two primary technical and strategic factors. Prior to this study, the Swiss Federal Office of Energy had already thoroughly validated the technical safety and financial feasibility of running the nuclear fleet for up to 60 years. Because Gösgen and Leibstadt were previously assumed by operators to be economically viable for only 60 years, the government specifically needed to investigate if a further 20-years would be feasible.
Beznau excluded from this specific 80-year study because it is already rapidly approaching its 60-year operating limit (2029 and 2031). Its operator, Axpo, has been conducting its own, highly complex technical feasibility assessments for Beznau. Because the small 365 MWe reactors are so old, the structural tracking required for them could not be easily grouped into the broader macroeconomic market model used for the larger, modern Gösgen and Leibstadt plants. In 2024, Axpo, which owns the Beznau plant and has a stake in the Leibstadt and Gösgen plants, announced that it would decommission the Beznau after around 60 years of operation.
