Forces Motrices Hongrin-Léman SA (FMHL)

The Forces Motrices Hongrin-Léman (FMHL) company was founded in 1963 with the purpose of constructing a pumped storage hydroelectric facility. The main features of the project are the Hongrin dam and the two underground pumped storage power plants on Lake Geneva, near Chillon Castle.

Characterised by the two elegant curved arches of its dam, the Hongrin reservoir represents a real stock of energy. Located near Col des Mosses, it has a capacity of 52 million m³ of water, which corresponds to around 100 GWh, or 10 days of electricity consumption of the whole canton of Vaud.

The reservoir is fed by the rain eight water catchments, and by water that is pumped up from Lake Geneva. All the facilities are located in the canton of Vaud. Because FMHL’s catchment area lies in the two cantons of Vaud and Fribourg, its operation is based on an inter-cantonal concession. The plant operator is HYDRO Exploitation SA.

• Type: Double arch dam

• Commissioned: 1971

• Height: 123 m / 95 m

• Crest: 600 m

• Reservoir capacity: 52 million m³

• Area: 160 ha

• Naturel catchment area: 46 km²

• Total catchment area: 90.8 km²

The Veytaux I station, which entered service in 1971, comprises four hydroelectric turbines, each with a capacity of 60 MW. The station can process water at a rate of up to 32 m³/s. In the reverse direction, the pumps can pump up to 24 m³/s of Lake Geneva water up to Lake Hongrin, 880 metres higher.

• Units: 4 x 2 Pelton turbines and 4 pumps

• Capacity: 240 MW

• Commissioning: 1971

In order to respond to the increasing demand for peak energy and balancing energy, FMHL doubled the capacity of the original facility by constructing a second power station, which was commissioned in 2017. Adjacent to the Veytaux I station, the Veytaux II station consists of two 120 MW generators.

• Units: 2 Pelton turbines and 2 pumps

• Capacity: 240 MW

• Commissioning: 2017