Hydropower, the energy produced in Haute Maurienne
Visible from the Canopée des Cimes, at the summit of the Val Cenis ski area, the Mont-Cenis dam enables EDF to generate electricity from hydropower, a 100% renewable energy source with zero greenhouse gas emissions.
The electricity generated in this way primarily supplies local areas, including Val Cenis . The electricity consumed to power the lifts, snow guns and premises is therefore renewable and carbon-free.
With the Mont-Cenis dam, as well as the Aussois and Bissorte dams, Haute Maurienne Vanoise is home to enormous water reservoirs. These facilities supply the Aussois, Avrieux, Villarodin and Bissorte hydroelectric power stations. On average, these facilities produce the equivalent of 2 times the annual residential consumption of the Savoie department.
At 320 million m3, Mont Cenis is France's largest rockfill dam.
Since the early 20th century, the Mont-Cenis plateau, whose waters flow naturally towards Italy, had been developed for hydroelectric production. After the Second World War, following the Peace Treaty of 1947, the border that passed through the Col du Mont-Cenis was moved in favor of France, which thus recovered the entire plateau, an ideal position for building a large-scale dam. The new dam, built by EDF between 1962 and 1969, created a reservoir with a capacity of 320 hm3, shared between the two countries at the rate of around 1/5 for Italy and 4/5 for France.
At 120 m high and 1.4 km long, the Mont-Cenis dam is the main component of the Haute Maurienne Vanoise hydraulic system. It is a so-called "gravity dam", meaning that its enormous mass of rock opposes the pressure of the water. To fill it, water is drawn from sources such as Bonneval sur Arc. The reservoir is even connected to the Plan d'Aval dam in Aussois, on the other side of the valley! A complex system of tunnels and penstocks transfers water from one reservoir to another, supplying the Villarodin, Avrieux and Aussois power stations as required.
The Mont-Cenis site has been the focus of a program of works designed to improve the landscape and preserve an international heritage, including the rehabilitation of the Grand-Croix mountain pasture, the undergrounding of power lines and the creation of a Franco-Italian network of hiking trails. The water from this development is also used in part to produce artificial snow for several ski resorts on Haute Maurienne Vanoise.
The Mont-Cenis dam is the last in France to be manned, due to its location on the border between France and Italy. The dam operators always work in pairs, with one French and one Italian technician. They spend several days on site, surveying the kilometers of gallery that criss-cross the mountain, taking readings and checking the quality of the installations.