Storm damage repaired: Grono power station fully operational again

25.02.2026 - The devastating storm in the Misox valley in southern Graubünden in June 2024 also caused severe damage to the Grono power station. The repair work took almost 18 months and cost around CHF 8 million. Since the end of 2025, the last of the three machine groups at the Grono power station has also been back in operation.

In short:

• A devastating storm caused extensive damage in the Misox valley in southern Graubünden in June 2024. There were fatalities, injuries and destroyed infrastructure.
• Axpo's six hydroelectric power plants were also damaged.
• The Grono power plant was hit hardest. It is only now fully operational again after around 18 months of repair work.

Axpo operates a total of six hydroelectric power plants in Misox: the OIM (Officine Idroelettriche di Mesolcina SA), Calancasca SA and ELIN (Elettricità Industriale SA) power plants, the small power plant operated by Tecnicama AG, and the small power plant operated by Idro Arvigo AG on behalf of BKW and the municipality of Calanca. The storms in June 2024 caused only minor damage to most of the plants, which were able to resume operation after a few days of interruption.

However, the Grono plant of Elettricità Industriale SA (ELIN), with the Roggiasca dam, the Grono power station and several water intakes, suffered very extensive damage. Axpo experts, on-site operating personnel and external employees worked flat out to repair the extensive damage. At the Grono power station, two of the three turbines were able to be put back into operation at the beginning of May 2025 after an outage of around 320 days. The third machine group followed at the end of December. After almost 18 months of interruption, the Grono power station is now fully operational again.

The renovation cost around CHF 8 million. Added to this were production losses, which Axpo was able to compensate for relatively well thanks to its large power plant fleet.

With around 60 plants, Axpo is the largest operator of hydroelectric power plants in Switzerland. In Graubünden, Axpo operates around 20 hydroelectric power plants with a capacity of 1,200 MW, which corresponds to around one third of Axpo's hydroelectric power production.