New construction of pumped storage power plant Nant de Drance

Tunnel surveying

Project

The Nant de Drance pumped storage power plant is one of the most important Swiss infrastructure projects for hydroelectric power generation. The consortium Straub Vermessungen AG/Geomy SA under the lead management of Straub Vermessungen AG has been commissioned by the client with the surveying.

Technical data

• Flow rate: 240 m3/s
• Drop height 250/375 m
• Inlet shafts D = 6.6m; L = 2 x 277 m
• Vertical shaft D = 6 m; H = 2 x440 m
• Upper valve chamber: LxWxH 60 x 15 x 18 m
• Underground turbine power plant: LxWxH 195 x 32 x 52 m
• Transformer plant: LxWxH 132 x 18 x 14 m
• Lower valve chamber: LxWxH 64 x 12,5 x 12 m
• Headrace channel: D = 6,60 L= 2 x 1230 m
• Supply and return work to the 2 lakes
• Various access tunnels (total 17 km)

Total cost

About CHF 1,900,000,000

Timeline

2008–2020

Customer

Nant de Drance SA, Chemin du Gilloud 3, 1920 Martigny

Services

• Conceptual design and implementation of the fixed point network 
• Large-scale, permanent deformation surveying
• Monitoring of approx. 18 km of tunnel excavation