Refurbishment of the Great St Bernhard Tunnel Turbine
The turbine located at the heart of the Great St Bernard Tunnel was completely dismantled, refurbished and reassembled by HYDRO. The work enabled the replacement of all seals and components subject to wear and tear and boosted output by 15 kW.
Complete refurbishment of the turbine
- Complete restoration of anti-corrosion coatings on all parts
- Repair or refurbishment of multiple components (electrolysis, chrome plating, welding, non-destructive testing, grinding of main rods, replacement of needles and mouthpieces, changing all seals, cleaning, etc.)
A pressure test was carried out in early April 2026, which showed the installation was fully watertight, before it was put back into service in mid-April in line with the original schedule. The boost to output is estimated to be 15 kW. HYDRO's completion of this service guarantees the hydroelectric plant's reliability, efficiency and complete suitability for the tunnel’s future operating requirements.
A unique installation built into the tunnel
This plant is the only example of a hydroelectric generation facility being built into the heart of an international tunnel. Six experts are responsible for the annual maintenance and technical monitoring of the facility, while 25 fire-fighters and operators oversee the tunnel and manage the fire system, which is closely linked to the dam and turbine.
