Wägital Power Station: Extensive maintenance work

15.04.2026 - Extensive maintenance work is set to begin at the Wägital Power Station this spring. The main focus will be on overhauling the safety throttle valve at the Innerthal water intake. This will be complemented by further work on the mechanical, hydraulic and electrical systems in the upper stage of the power station. In total, AG Kraftwerk Wägital is investing around 3.5 million Swiss francs. AG Kraftwerk Wägital is a joint venture between Axpo and ewz, each of which holds a 50 per cent stake.

In brief:

• The safety throttle valve at the Innerthal water intake has been in continuous operation since the 1960s and needs to be overhauled.
• AG Kraftwerk Wägital is investing around 3.5 million Swiss francs in the maintenance work, making a significant contribution to future operational safety.
• The upper stage of the Wägital power station will be taken out of service for around three months.

The safety throttle valve at the Innerthal water intake is central to the safe operation of the upper stage of the Wägital power station. It is located inside the pressure tunnel and is normally in the open position, allowing water from Lake Wägital to flow through the pressure tunnel to the Rempen power station. In the event of an emergency, the valve would close automatically, preventing further water from Lake Wägital from entering the pressure tunnel. It has been in continuous operation since the last overhaul in the 1960s and is now undergoing a major refurbishment. To this end, the valve, which has a diameter of around 2.4 metres, will be removed from the water intake and overhauled by an external contractor. At the same time, the control system for the safety throttle valve will be converted from the existing oil-hydraulic system to an environmentally friendly water-hydraulic system.

The maintenance work also includes replacing the data cable between the Innerthal water intake and the Rempen power station control centre. The new fibre-optic cable runs for a length of around 3.7 kilometres inside the pressure tunnel. In parallel, the mechanical, hydraulic and electrical systems at the Rempen control centre are being inspected and repaired.

Upper power station stage out of operation for around three months

AG Kraftwerk Wägital is investing around 3.5 million Swiss francs in the maintenance work, thereby making an important contribution to the future operational safety of the upper power station stage. During the overhaul, the upper stage will be taken out of operation for around three months. During this time, no water can flow out of Lake Wägital through the pressure tunnel. The water level has been lowered in advance to accommodate the natural inflow from the Lake Wägital catchment area. During the construction work, there may be temporary disruptions on Seestrasse in the vicinity of the water intake.

AG Kraftwerk Wägital is a joint venture between Axpo and ewz, each of which holds a 50 per cent stake. It generates around 128 million kilowatt-hours of electricity annually, which corresponds to the annual electricity consumption of around 35,000 households.