Developing new infrastructure to efficiently evacuate the renewable electricity generated offshore


The development of renewable marine energies, particularly offshore wind power, is a key aspect of the French government’s plan to diversify the country’s electricity mix. The targets set forth in the draft Multiannual Energy Programme published early in 2019 call for about 5 GW of capacity to be in service by 2028, possibly approaching 10 GW by 2035. Contracts for the first six offshore wind farm projects, using fixed turbines with a unit capacity of about 500 MW each, were awarded through two calls for tenders (AO1 and 2) in 2012 and 2014. These projects have run into major delays, notably because of lengthy authorisation procedures and the many appeals lodged over those authorisations. The farms are now expected to be in service in 2022.

A new legislative framework has expanded RTE’s responsibilities in terms of connecting offshore wind farms. For future tenders, starting with AO3, the “hydrocarbon law” will require that RTE cover all costs associated with connections via the TURPE tax, and, logically, it will be the contractor for all connection work, including offshore substations. These measures are intended to allow for the sharing of certain infrastructure and thus the optimisation of connection costs. The ESSOC act of August 2018 further expanded its connection responsibilities to AO1 and 2 projects (excluding offshore substations, which are still the responsibility of the contract winners) to assist the government in its renegotiation of contracts.

Barbara Pompili, French minister of the ecological transition, and Annick Girardin, minister of maritime affairs, announced on 5 December 2020 that an area off the coast of Cotentin, in Normandy, has  been selected for the construction of a new offshore wind farm with a capacity of around 1 GW. They simultaneously launched a call for bids for the development of the farm in 2022. This project will lead to the construction of a fourth offshore wind farm on the eastern English Channel – North Sea side.

Work began during the year to connect offshore wind farms in Saint-Nazaire, Saint-Brieuc and Fécamp to the power grid.

Offshore wind farm connection projects

Closer look

Better understanding

Saint-Nazaire offshore wind farm


A consortium led by EDF Énergies Nouvelles (now EDF Renouvelables) was selected to build a wind farm off the coast of Saint-Nazaire, comprising 80 6 MW wind turbines, for a total capacity of 480 MW.

To connect this offshore wind farm to the existing grid, RTE will build a 33 km subsea link and a 27 km 225 kV underground line passing through Saint-Nazaire, Trignac, Montoir-de-Bretagne, Donges and Prinquiau. The project also calls for the construction of a substation in Prinquiau so that the energy produced by the offshore wind farm can be integrated into the transmission grid.

Installation in May 2020 of the ducts for the future subsea cables

Closer look

Better understanding

Saint-Brieuc offshore wind farm


RTE is tasked with connecting to the transmission grid the 496 MW wind farm in the Bay of Saint-Brieuc, built and operated by a company called Ailes Marines. The project involves the creation of a 225 kV double-circuit line, starting underwater and running for 16 km underground to the existing Doberie substation, in the town of Hénansal.

Work got underway in October 2020 to expand the Doberie substation

Closer look

Better understanding

Fécamp offshore wind farm


The wind farm off the coast of Fécamp represents 500 MW of generation capacity. Connecting it will require the creation of a 225 kV double link, starting out underwater and continuing underground. It will span 50 km in all including 18 km subsea, up to the landing point in the port of Fécamp, and 32 km underground, stretching to the Sainneville-sur-Seine substation.

Closer look

Better understanding