A Swiss utility and a federal railway have agreed to proceed with construction of the 600-MW Nant de Drance pumped-storage project at Finhaut in the Swiss Alps.
The boards of utility Aare-Tessin AG fur Elektrizitat (Atel) and federal railway SBB voted to approve building the 990 million franc (US$950 million) project. Atel is to own 60 percent of the project, while SBB owns 40 percent. (HNN 8/4/06)
Approval is subject to a license and building permit being issued and additional cost limits being set for construction and operation, Atel said. Construction is scheduled to begin in mid-2008 with operation in 2015.
Nant de Drance is to include an underground powerhouse containing four 150-MW variable-speed pump-turbines, a transformer cavern with common access tunnel of 5,500 meters starting at Le Chatelard, two parallel water conveyance systems with 250-meter headrace tunnel, 470-meter vertical shaft, 160-meter steel-lined pressure tunnel with manifold, and tailrace tunnel with manifold.
The project is to utilize the height difference of two existing reservoirs, Emosson and Vieux Emosson, in Finhaut between Martigny and Chamonix, to produce peaking power. Access to the completely underground plant is to be by a five-kilometer tunnel, minimizing environmental effects of the big power station.
Atel said Nant de Drance will make a key contribution both to securing supply for the Swiss electricity grid and to covering the pronounced consumption peaks in railway operation of SBB and other private railways supplied by SBB, such as TRAVYS and BLS.
Atel said the right machine technology can offset grid fluctuations and irregular production from renewable energies instantaneously. With state-of-the-art technology, the plant is expected to achieve greater than 80 percent efficiency.