Pumped Storage Power Station Nant de Drance, Finhaut

Construction of a pumped storage station between the existing Emosson and Vieux Emosson reservoirs, in several caverns. The new power station cavern is located at approx. 1,700 m above sea level. Access is granted from below via a five kilometre long gallery and from above via a two kilometre long gallery system. The height difference between the entrance and the turbines is overcome by dropping vertical pressure shafts. In addition to the shell construction of the power station, the contract includes management of the excavated material.

  • Main access gallery: Heading using tunnel boring machine in hard rock
  • Gripper TBM
  • Access galleries and caverns using drill & blast
  • Shafts: Raise drill and drill & blast
  • Pressure galleries using drill & blast


Specific figures

Order value

CHF 560 million

Construction period

2008 - 2016


12'000 m

Total excavated surface

70 m2