After ten years of work, the Romanches Gavet dam, in Isère, has just come into operation.
It is the largest underground dam in France. The Romanches Gavet dam, in Isère, is also the last major EDF hydropower project. The installation, with a gallery 10 kilometers long underground, was officially inaugurated on Friday 9 October. Despite this industrial success, this type of project risks remaining without an heir.
It is a 92-ton turbine which has just started up under water pressure. It took ten years to dig this dam in the mountain. This is a technical feat, says Sébastien Farge, the operations manager. “The peculiarity of this work is that it has dug a 10-kilometer gallery that brings back the water. This gallery was dug in the heart of the mountain by two tunnelers.”
A little further on, we come across the factory cave, an underground cathedral that houses the heart of production, details Daniel Perra, the site manager. “The size is as large as the nave of Notre-Dame de Paris. In this cave we have installed the equivalent of a five-storey building which allows us to place all the equipment on it that will allow us to produce energy “, he explains. However, vu from the outside, impossible to guess the giant hiding in the mountain. This 400 million euro project has replaced six factories and dams more than a century old.
The dam produces 40% more electricity than the old installations, continues Yves Giraud, director of EDF hydro. “In the energy transition, hydroelectricity is called to take a new place. It is controllable, flexible and storable. You can have electricity when you need it. At EDF level, 14 gigawatts can be mobilized , that’s the equivalent of 14 nuclear reactors. “
Despite these demonstrated qualities, the development of hydropower in France has stalled since 2015. Paris and Brussels are opposed to the award of hydropower concessions, almost all of which are operated by EDF. The European Union wants them to be open to competition, under a directive. “This situation has frozen any development of new hydraulic capacities in France while there is significant untapped potential”, regret Jean-Bernard Lévy, CEO of EDF.
In the meantime, major projects remain in the pipeline. Especially since unlike solar and wind, hydroelectricity does not benefit from any assistance either in the recovery plan, or via guaranteed selling prices.