The 400 million m3 stored in the Grande Dixence reservoir represent a major energy potential. They represent a fifth of all energy stored in Switzerland. To make the hydraulic force of the Lac des Dix as profitable as possible, Grande Dixence drives water through its turbines at two levels. The first is at an altitude of 1490 m in the Fionnay power plant. The second is level with the Rhône, 1000 m lower at the Nendaz power plant. To transform this mass of water into electricity, to domesticate this tranquil force into billions of kWh the power plants at Fionnay and Nendaz work in relay. With the current installations at Fionnay and Nendaz, the Grande Dixence complex produces a total power output of 800 MW. The Bieudron power plant enables this power output to be increased by 1,200 MW, thereby taking the total power output of the complex to 2,000 MW. Like other hydroelectric facilities, the main purpose of Cleuson-Dixence is to provide power instantly, on demand. In just 4 minutes, the installation is able to provide the network with power equivalent to that of a nuclear power station! The energy produced across all the Grande Dixence/Cleuson-Dixence facilities reaches more than 2 billion kWh per year, which corresponds to the average annual consumption of 500,000 households.
