Commissioned in 1979, Cheylas Pumped Storage Power Plant operates with two reversible pump-turbines rated at 240 MW each, the most powerful in France. The elevation drop between the upper reservoir, Bassin du Flumet, and the powerhouse is 261 meters, and the power plant empties into Bassin du Cheylas.

In December, 2012, the European Commission awarded a $21.55 million grant to a consortium, which includes Alstom, Electricite de France (EDF), Elia, Imperial College, DNV Kema and Algoe, to add 70 MW of capacity to Cheylas by converting it to a variable-speed pumped storage plant.

Open-loop Pumped Hydro Storage