Nant de Drance - Power station to meet peak capacity
Alpiq, SBB, IWB and FMV are jointly investing approximately 1.8 billion Swiss francs in the Nant de Drance pumped storage power station in the Lower Valais. The 900 megawatts project makes an important contribution to the energy security of Switzerland and the public transport system. The construction work started in 2009 and is expected to be completed in 2017. Currently the cavern, which will house six 150 megawatts pump turbines, is being excavated.
The pumped storage power station is being constructed below ground between the two existing Emosson and Vieux Emosson reservoirs, situated in the community of Finhaut. The water will be released from the Vieux Emosson reservoir over the turbine generators to the Emosson reservoir 300 meters below. During off-peak hours the water is pumped back from the lower to upper reservoir. Equipped with turbine capacity of 900 megawatts, the Nant de Drance power station is expected to generate around 2500 million kilowatt-hours of peak energy a year. The pumps will consume 20 percent more energy than they generate.
The environment remains intact
The construction work has a very low impact on the landscape, because the chamber housing the power station lies deep under rock, with access to the chambers through a five-kilometre long tunnel. The tunnel entrance is located next to the Swiss Railways SBB power station Le Châtelard. The electricity generated will be fed into the 380 kV grid that is to be constructed between Le Châtelard and Rosel.