Modernisation of the Mottec hydroelectric power station

Mottec's project, which began in 2014, was aimed at modernising the electromechanical units comprising the alternators, turbines, transformers, foot valves and cooling systems. The first of three sets was commissioned in 2021, and the last was completed at the end of August 2024.
The Mottec power station, a true marvel of Swiss engineering dating back to 1959, diverts water from the upper regions of the Tourtemagne valley via a small reservoir at an altitude of 2,170 m and pumps it into the Moiry dam at altitudes of between 2,100 and 2,248 m from the Mottec power station at 1,560 m. More than 50% of Lac de Moiry, which has a volume of 77 million m3, is filled in this way by glacier meltwater, which feeds Lac de Tourtemagne on the other side of the valley during the summer months. This water is then stored and turbined, particularly during the winter months.
We are proud to have been commissioned by Forces Motrices de la Gougra SA for this major modernisation project, which has increased the capacity of the turbines by 25%.