Executive Summary
Switzerland secured its electricity supply during winter 2025/26 despite the shutdown of the Gösgen nuclear power plant through net imports of 6.8 TWh – approximately one-fifth of winter demand. Hydroelectric power production fell below previous year levels. The spot market price averaged 120 EUR/MWh. For the coming winter, the Iran war and blockade of the Strait of Hormuz create uncertainties regarding gas supply and thus electricity availability. Elcom warns of deferred maintenance in the transmission network and calls for legal simplifications.
People
- Elcom (Swiss Federal Electricity Commission; regulatory authority)
Topics
- Electricity supply security
- Nuclear energy and energy transition
- International electricity imports
- Geopolitical energy risks
- Network infrastructure
Clarus Lead
Switzerland faces a critical supply problem in winter 2026/27: While the current market price structure does not yet signal physical electricity scarcity, a combination of prolonged Hormuz blockade, insufficiently filled European gas storage facilities, and cold weather with low wind power could trigger an extreme scenario. Unlike the 2021/22 crisis, Europe today has larger LNG capacities and France has high nuclear power production – but these buffers may not be sufficient. In parallel, the medium-term infrastructure crisis is intensifying: 60% of electricity pylons are 50–80 years old and require renewal; without accelerated approval procedures, a bottleneck in network expansion threatens.
Detailed Summary
Winter Balance 2025/26 and Import Dependency
The Gösgen nuclear power plant normally covers 13% of winter consumption. Its shutdown until March 2026 resulted in unprecedented import dependency: 6.8 TWh net imports correspond to approximately one-fifth of seasonal domestic demand. These were obtained predominantly from France, where high nuclear power production created surpluses and dampened market price levels. Hydroelectric power production reached the long-term average, but remained significantly below the levels of 2023/24 and 2024/25, which further increased import requirements. No technical or regulatory restrictions on import capacities existed – a fortunate circumstance that stabilized supply.
Geopolitical Risks for Winter 2026/27
The Iran war and Hormuz blockade since March 2026 have noticeably driven up liquefied gas prices and pushed European gas storage to relatively low fill levels. The market price structure shows an inverse picture: short-term gas deliveries are more expensive than winter contracts – an incentive against precautionary purchases. Should European gas storage not be adequately filled by autumn, gas power plants could become a bottleneck in winter. An extreme scenario combines prolonged Hormuz blockade, insufficient storage fill levels, persistently low temperatures, and low wind power production – this would drive gas consumption and electricity prices up while simultaneously reducing gas power plant availability.
Network Infrastructure and Lessons from the Iberian Blackout
Elcom calls for acceleration of maintenance on approximately 12,000 electricity pylons: 60% are between 50 and 80 years old. The so-called "network express" is intended to simplify approval procedures – through an "overhead line principle" and a "non-deterioration rule" that make existing routes usable without new obstacles. The blackout on the Iberian Peninsula in April 2025 showed that voltage maintenance, black-start capability, and network recovery are central. Switzerland is less vulnerable due to its production mix and geographical location, but the lessons must be incorporated into European network standards.
Key Messages
- Electricity supply winter 2025/26 secured through record imports (6.8 TWh), but with high dependency on French nuclear power and no technical bottlenecks
- Iran war and Hormuz blockade create uncertainty regarding gas supply and thus electricity availability for winter 2026/27; extreme scenario possible, but not probable
- Medium-term infrastructure crisis: electricity transmission network aging (60% of pylons 50–80 years old); network express reforms necessary to accelerate renewal
Critical Questions
Evidence/Data Quality: How robust are the forecasts for refilling European gas storage by winter 2026/27? What assumptions about Hormuz blockade duration underlie the scenarios?
Conflicts of Interest/Independence: To what extent does French nuclear power production influence Elcom's risk assessment? Are dependency structures sufficiently addressed in the analysis?
Causality/Alternatives: Could renewable energy expansion reduce gas dependency faster than planned? What alternative import sources (Norwegian hydropower, wind power) are being examined?
Feasibility/Risks: How realistic is the acceleration of network maintenance through the "network express"? What environmental or planning obstacles could cause delays?
Data Quality – Historical Comparability: Are spot market prices (120 EUR/MWh) directly comparable to 2021/22 crisis values, or do market structures differ?
Scenario Robustness: The extreme scenario combines three simultaneous shocks (blockade, storage, weather). How statistically probable is this combination?
Regulatory Risk: What EU decisions on LNG infrastructure or electricity market design could endanger Swiss supply security?
Network Stability Post-Blackout: Have concrete measures for voltage maintenance and black-start capability been initiated in Switzerland, or do these remain at the study level?
Source Directory
Primary Source: Swiss Federal Electricity Commission (Elcom) – Review and Outlook on Electricity Supply Security 2026 – https://www.news.admin.ch/de/newnsb/pmdramXPsQ6lVTQ7o2xT-
Supplementary Sources:
- ENTSO-E – Final Report Blackout Iberian Peninsula (April 2025), published 20 March 2026
- Swissgrid – Swiss Electricity Transmission Network (Infrastructure Status)
Verification Status: ✓ 07.05.2026
This text was created with the support of an AI model. Editorial Responsibility: clarus.news | Fact-Check: 07.05.2026