Besides collecting water from the River Gougra, the reservoir is also a depositary for ice and snow. More water flowing from the upper Turtmann Valley collects in the reservoir below the glacier and is pumped into Lac de Moiry. Once the lake is full, the water table is exactly 2,249 meters above sea level.
Hydropower is an important arm of the economy in Swiss alpine regions: after all, more than half of the electricity produced in Switzerland is generated from water. At around 10,000 GWh per year, the canton of Valais accounts for no less than one fifth of the electricity consumed in Switzerland. And Kraftwerke Gougra AG contributes an annual volume of 639 GWh. The water stored in the Moiry reservoir is channelled through turbines in three downstream power stations: Mottec, Vissoie and Chippis.
In view of the fact that water is the most important source of renewable energy and that the generation of electricity from water is regarded as environmentally friendly, hydropower has consistently been accorded top priority at Alpiq. In addition to storage power stations such as Lac de Moiry, Alpiq's power plant park also includes various run-of-river and small hydroelectric power stations.