The construction works for the Nant de Drance pumped storage power station in the Valais municipality of Finhaut began in September 2008. The official inauguration of the construction site then took place on 30 June 2009 in the presence of more than 100 guests. Nant de Drance is one of the most important Swiss infrastructure projects for hydroelectric power generation. With its 600 megawatt turbine and pumping capacity, the plant will make an important contribution to energy supply security in Switzerland. The possibility of increasing capacity to 900 megawatts is currently being examined. The power station is scheduled to be commissioned in stages as from 2015.
The facility is being built completely underground and therefore with minimal environmental impact. Access to the caverns located 1,700 metres above sea level is through a 5.6 kilometre-long tunnel on the territory of the Valais border municipality of Finhaut between Martigny and Chamonix.
On 11 December 2009 Nant de Drance SA ordered the 4 x 175 MVA generator transformers from ABB Switzerland for a total amount of approx. 15 million francs. This means that a Swiss supplier has again made the running for the award of a key element, in addition to the adjudication of the construction works to the Marti Implenia consortium and the machine engineering to Alstom Hydro Schweiz in Birr.