The dam is part of the cascade construction of diversion HPP with total capacity of 363 MW. Its purpose is the creation of a large water reservoir, simply put, the reservoir, the water from which through derivation is fed to two hydroelectric power stations – Fionnay (Fionnay) and Riddes (Riddes).
First, the water from the lake Mauvoisin is supplied to the three radial-axial turbines of hydroelectric power station Fionnay power in the amount of 138 MW. The elevation forms a pressure altitude of 482 meters. The water then goes to the station Rides where falling from a height of 1014 metres, spins Pelton turbines five generating units with a total capacity of 225 MW. Together the two plants produce 943 million kilowatt-hours per year.
Despite the large size of the dam, the capacity of the cascade is rather small if we compare with our HPS. For example, the power of the Chirkei hydroelectric power station, which has a similar arched dam height 232м is 1000 MW, and if you remember Sayano-Shushenskaya, which, though the highest in Russia, but at 5 meters below Mauvoisin, its maximum power of 6400 MW (almost 18 times more powerful!).
The construction of the dam was started 1951, and was completed early in 1957, vodohranilishe completely filled already in 1958. The initial height of the dam was 237 m. In 1991, he added another 13 meters, the reason for this was the need to increase the volume of the reservoir in winter.
The Mauvoisin lake (Lac de Mauvoisin is one of the largest reservoirs in Switzerland. The maximum amount of lake – 211,5 million m3 and an area of 208 Hectares, a catchment area of 114 km2. The lake lies at an altitude of 1961 m.
In addition to producing electricity, the dam serves to control flooding, predotvraschaya floods, such as those that occurred here in 1595 and 1818
1960-70-ies above the dam was threatened in the form of Giétro, one of the largest glaciers of the Swiss Alps, premakumara to the lake Mauvoisin. Due to possible icefalls there was a risk of overflow of the reservoir, but since 1980, the glacier began to recede. Have taken all measures to ensure that such never happens again.