Construction and operating company for the pumped storage power station in the Swiss canton of Valais
Nant de Drance SA is responsible for the planning, the construction and the operation of the pumped storage power station of the same name. The share capital of the Limited Company (SA) is 50 million Swiss francs. With the newly founded company, Atel and SBB have defined their cooperation for the pumped storage power station.
The construction work for the 600 MW Nant de Drance project began in September of this year. The initial work consists of ground clearance, the felling of trees in Châtelard and the building of a pre-tunnel to permit ease of access to the site. The main work on the five kilometre tunnel should be started at the beginning of next year.
The Nant de Drance project intends to use the difference in height between the two existing reservoirs, Emosson and Vieux Emosson, on land belonging to the Valais border municipality Finhaut and situated between the towns of Martigny and Chamonix, for the generation of peak-load electricity. The Nant de Drance power station is designed with turbine and pump capacities of around 600 Megawatts and will produce electricity of 50Hz. The plant will be built completely underground. Access to the cavern, which lies 1,800 metres above sea level, will be via a five kilometre long tunnel. Thus the large power station can be built with minimal effects on the environment.
In consideration of the development in the demand for electricity at peak times, Nant de Drance will provide an important contribution both to the security of supply in the Swiss electricity grid and to covering the pronounced load peaks in the railways operating network of the SBB and several private railways, such as TRAVYS (Transports vallée de Joux, Yverdon-les-Bains, Ste-Croix SA) or BLS, which are supplied with electricity by the SBB. Thanks to the appropriate machine technologies, variations in the supply grid as well as those caused by the irregular output from renewable energy sources can be compensated within the shortest possible time. With its state-of-the-art technologies, the plant will operate with an exceptionally high efficiency in excess of 80 percent.
The project is budgeted at around 990 million Swiss francs. The plant is to go into service in phases from 2015.