Klingnau Aare Power Station: Complete refurbishment after over 90 years of hard work

The Klingnau Aare power station has been reliably generating electricity for over 90 years. Axpo and AEW Energie AG are investing around 105 million Swiss francs in a comprehensive refurbishment, thereby ensuring its continued operation for a further 50 years. In addition, electricity production will increase by 11 per cent to 230 million kilowatt-hours. Work began in spring 2026 and is expected to take around six years.

The Klingnau Aare power station is idyllically situated near the Klingnauer Stausee nature reserve and local recreation area. Every day, numerous day-trippers and sports enthusiasts use the walking and cycling path that runs right through the power station site. What they are currently seeing are the first signs of a major project that will last for the next six years. Axpo and AEW have launched a comprehensive refurbishment of the Klingnau Aare power station. The work is expected to last until 2032 and will ensure the power station is fit for a further 50 years of electricity generation. 

Open-heart surgery

At the heart of the project is the refurbishment of the three turbines and generators – an investment of around 71 million Swiss francs. After more than 90 years of heavy-duty operation, the equipment has reached its limits. “In the generators, the stator and rotor windings have exceeded their technical service life. In the turbines, components have worn out after such a long period of operation,” explains André Kaufmann, operations manager at the Klingnau Aare power station. It is a project with a number of challenges, as Kaufmann says. “The machine groups – that is, the turbines and generators – are being hoisted into the machine hall for the first time in 90 years of operation.” The work is being carried out in stages, effectively like open-heart surgery. “We are only ever working on one of the three machine groups at a time; the other two remain in operation and continue to generate electricity.” Each machine group is out of service for around 15 months.

Following the refurbishment, the Klingnau Aare power station will be able to produce around 230 million kilowatt-hours of electricity annually – that is 11 per cent more than before the refurbishment and corresponds to the electricity requirements of over 55,000 four-person households.

More than ‘just’ new machinery: a comprehensive refurbishment

The refurbishment is not limited to turbines and generators. A total of 105 million Swiss francs is being invested in the complete refurbishment of the power station. This includes:

In the turbine hall: replacement of the two cranes in the turbine hall, as well as modifications to the control systems, voltage regulators, turbine governors and the power supply for the plant’s own needs – the ‘brain’ and the ‘nervous system’ of the power station.

All round: The weir drives are being refurbished, and new screen cleaning machines are being installed. The intake screens are being replaced.

For nature: a new, state-of-the-art fish passage system with four entry points and attraction pumps is also being built, enabling fish to migrate upstream. A barrier against the invasive fish species, the Black Sea gudgeon, is also to be installed. Construction costs: around 12.9 million Swiss francs.

Hiking and cycle path to be rerouted

The public hiking path through the power station site is being rerouted. Instead of crossing the upstream bridge at the turbine house, it will in future cross the transformer bridge and go round the power station grounds – primarily for safety reasons, as this will allow power station operations and leisure activities to be kept separate.

The two bridges over the internal canal will also be refurbished, giving them a higher load-bearing capacity. André Kaufmann reveals yet another, eye-catching refurbishment measure: “The machine house is to be given a fresh coat of paint.” The colour, however, remains a secret for now – we can look forward to finding out.