Pumping power

Alstom has been awarded a €125m (£111) contract to equip the new Nant de Drance hydropower station, near Finhaut in the south-west Canton Valais of Switzerland, with its first variable-speed pump storage power plant.

The project, a venture between Swiss energy provider Alpiq, Forces Motrices Valaisannes (FMV) and Swiss federal railways SBB, demonstrates the first ever use of this type of system in Switzerland.

With a total power-generation capacity of 628MW, the new plant will eventually supply an average power consumption equivalent to more than 600,000 homes.

Alstom will supply four of its 157MW vertical Francis reversible turbines and four 170 MVA vertical asynchronous motor/generator units to the new plant and will handle the commissioning of the equipment.

The new installation will use both a conventional pump turbine and a variable-speed pump turbine.

The former pumps the water into a reservoir during periods of low energy demand and releases it to produce energy during peak times, while the latter regulates the level of energy it consumes.

Alstom Hydro’s facilities in Grenoble, France and Birr, Switzerland, will be in charge of the engineering and manufacturing of the equipment.

Switzerland produces about 66,000GWh of energy per year, with hydroelectricity making up more than 50 per cent.

Because of increasing demand and an ageing fleet, some 25,000 to 35,000GWh per year will need to be replaced or renewed by 2035, representing about 50 per cent of today’s installed capacity.