THE LARGEST HYDROELECTRIC PROJECT IN FRANCE

EDF, the French electricity company and the leader of hydropower in Europe, conducted the largest hydroelectric project in France. What made this project so special and so impressive? EDF aimed to replace the previous six existing power plants and the previous five existing dams located in the Romanche valley by a single hydroelectric facility and a single dam. Started in 2013, this giant project extends over 10 km in a French village called Livet-et-Gavet. It is composed of three key areas: the new dam located in Livet, the new 9.3 km underground intake tunnel – which connects the dam to the power plant – and the new power plant entirely underground too, located in Gavet.

This new complex is now more powerful (+40%), more environmentally friendly and will fit better into the landscape. It was designed to optimize the hydroelectric potential of the Romanche river and increase the energy production for the region.

A CUSTOMIZED DESIGN TO INCREASE THE OUTPUT OF THE HYDROPOWER PLANT

EDF Hydro, one of GE Renewable Energy’ longtime customers, had called upon our teams’ expertise to contribute to this colossal project.

GE Renewable Energy was responsible for the study, the manufacturing, the supply, the erection and the commissioning of the two 49 MW Francis turbines-generators. The performance of the plant depended on its new runners built with a unique design.

This new design started in our Hydro laboratory in Grenoble, France, where we conducted a detailed study to define the most suited design to the specifications of the project. The shape of this runner, its number of blades and its profile make it unique. GE’s experts manufactured a model test to validate and confirm the performances of this new runners expected by EDF.

The quality of GE equipment and the precision work of the teams were critical in this project. To meet the objectives of EDF Hydro, the manufacturing of the turbines and the assembly of our machines had to respect a tolerance of only a few hundredths millimeters.

After the successful erection of the turbines, generators and main inlet valves performed by the GE’s Hydro Solutions teams in 2019, the wet commissioning of the two new units started beginning of 2020 and ended during summer 2020. The good collaboration between GE Renewable Energy Hydro Solutions and EDF teams enabled the completion of all the required test, including the turbine performance test, despite the COVID-19 pandemic period and the associated restrictions.

Training sessions will be provided by the GE’s Hydro teams to the EDF Operation and Maintenance teams to help them leverage their knowledge and skills and consequently operate the Romanche-Gavet plant in the most efficient way.

These new turbines will provide a high output over a large operating range in order to address the flow variations of the Romanche river. The hydropower plant of Gavet should generate 560 GWh per year, equivalent to a 40% increase in energy production in regard to previous installed base.