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Bay of Saint Brieuc Offshore Wind Power Plant

Bay of Saint Brieuc wind power project is a 496MW offshore wind farm being developed on the north-west coast of France.

Project Type

Offshore wind farm


Offshore France



Start of Construction



Bay of Saint Brieuc wind power project is a 496MW offshore wind farm being developed on the north-west coast of France.

The wind power plant will generate 1,820GWh of clean energy every year, which will be sufficient to meet the requirement of 835,000 homes.

The Saint Brieuc wind farm is the first large-scale offshore wind farm in Brittany and one of the biggest commercial-scale offshore wind projects in France.

The project will be fully developed, constructed and operated by Iberdrola’s affiliate Ailes Marines. Iberdrola gained 100% ownership of Ailes Marines, following the acquisition of the remaining 30% capital from Avel Vor.

The offshore wind farm is being developed with an investment of €2.4bn ($2.7bn). It will create over 2,000 direct jobs and thousands of indirect jobs. The project construction is expected to start in 2021 and the project is scheduled for completion in 2023.

Saint Brieuc offshore wind farm location

Saint Brieuc wind farm will cover an area of approximately 75km² in the English Channel.

It will be located 16.3km off the coast of Saint-Brieuc Bay in Brittany, north-western France.

Saint Brieuc offshore wind farm make-up

Saint Brieuc offshore wind power plant will comprise 62 SG 8.0-167 DD offshore wind turbines configured in seven rows.

"The Saint Brieuc wind farm is the first large-scale offshore wind farm in Brittany."

With a capacity of 8MW each, the 207m-high turbines will be equipped with direct drive technology, which uses fewer moving parts compared to geared machines. The turbine blades will be 82m long with a swept area of 18%.

The 225kV offshore cable will include two lengths of 33.5km three-core cable with a hybrid armouring solution. It will also feature a fibre optic element, which will facilitate remote monitoring of the cable link and data transmission between the offshore wind farm and the land base. The onshore power export cable will comprise 93km of 225kV single-core cable.

The wind farm will witness the installation and commissioning of 90km of 66kV alternating current (AC) high-voltage connection cabling and three cross-linked polyethene (XLPE) insulation hubs for the submarine connection cabling systems. It will be connected to the grid via a 225kV submarine link and a 225kV land link.

Saint Brieuc offshore wind farm construction details

The first phase of development, involving analysis of the technical and environmental conditions of the site, is completed.

The optimum orientation of the wind turbines for the highest possible energy yield was determined using laser imaging detection and ranging (LIDAR) system. Offshore operations, beginning in 2021, will include the installation of pin piles and offshore substation, using offshore installation vessel Aeolus. A second vessel will join the works in 2022 for the installation of 62 jacket foundations of steel lattice structure.

The offshore and onshore export cables will be laid by CS Skagerrak vessel, and the cables will be trenched into the seabed, using a specialised Capjet system.

The major components of the turbines will be manufactured at Siemens Gamesa’s proposed offshore wind turbine factory in Le Havre, France.

Contractors involved

Siemens Gamesa Renewable Energy (SGRE) was contracted to supply and build the wind turbines. The order also includes a ten-year turbine maintenance agreement.

Navantia-Windar was awarded a €350m ($393m) contract for the construction and assembly of jackets and their corresponding piling. Van Oord will transport and install these jacket foundations and the offshore substation.

Prysmian Group will provide the submarine connection cabling systems under an €80m ($90m) contract. The links for grid connection will be designed, built and maintained by French transmission system operator RTE.

Nexans was awarded a €115m ($127m) contract by RTE France for providing the export cables. The offshore cables will be manufactured at Nexans’ facility in Halden, Norway, while the onshore cables will be supplied by Nexans’ Benelux facility in Belgium and the fibre optic elements will be procured from its plant in Rognan, Norway. The company will also provide inspection, maintenance and repair (IMR) services as part of the contract.

IDOM was contracted to conduct 3D modelling of the substation’s metallic structure, including the jacket foundation and different levels of the topside structure. It is also involved in the layout of electrical, heating, ventilation and air conditioning (HVAC), piping, cable trays and fire protection equipment for the wind farm.

NKE Instrumentation is providing oceanographic buoys for monitoring the construction work. It also collaborated with local partners for manufacturing floats, data processing and chartering of vessels.

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