Saint-Brieuc: Iberdrola's first large-scale offshore wind power project in Brittany

When it becomes operational in 2023 it will have a total installed capacity of 496 megawatts (MW), capable of generating enough clean energy for 835,000 people.

Saint-Brieuc Bay, France

Wind turbines number
62 SG 8.0-167 DD turbines

16 km off the French coast

Total installed capacity
496 MW

2.4 billion euros

Start of the operational phase


Brittany is prone to strong winds and high tides, which have shaped the region's landscape, economy and way of life. With a view to leveraging the region's full energy potential, the company designed the Saint-Brieuc offshore wind farm: the first large-scale offshore wind farm in Brittany and one of the first in France to obtain all the necessary government permits for its construction and operation.

With an investment of 2.4 billion euros it is estimated that, once commercialisation begins in 2023, it will produce 1,820 gigawatt hours (GWh) per year, which will supply energy to 835,000 people.

This will be possible thanks to a total installed capacity of 496 megawatts (MW) from 62 turbines each generating 8 MW of power, which will cover a surface area of 75 km2 located some 16 km off the French coast.


Saint-Brieuc offshore wind farm location.#RRSSSaint-Brieuc offshore wind farm location.


Iberdrola group, in collaboration with French companies RES and Caisse des Dépôts, both belonging to the consortium Ailes Marines (property of Iberdrola after the recent acquisition of all of its shares), has finished the first phase of construction of the project: analysis of the technical and environmental conditions of the site.

This first step involved installing three wind measurement systems in the area where the farm is located and which have recorded the wind power potential in the area during the last two years. They will do so using the LIDAR (Laser Imaging Detection And Ranging) system, which by laser determines in a precise way the direction of the prevailing wind in order to identify the optimum orientation of the wind turbines for the highest possible energy yield.

Saint-Brieuc will also have Spanish involvement since its 62 jackets — the structures that support offshore wind turbines — and their corresponding piling will be entirely built by Navantia-Windar, in Fene (A Coruña) and Avilés (Asturias), respectively. The final assembly of all component parts will be completed at the Galician shipyard facilities.

The contract, worth €350 million, is the largest offshore wind contract in the shipping company's history and will help create over 2,000 direct jobs and thousands of indirect jobs.

The Dutch marine contractor Van Oord has been selected to transport and install the 62 jacket foundations and offshore substation. Van Oord will start the offshore operations in 2021 with the installation of the pin piles and the offshore substation. To do so, it will deploy its offshore installation vessel Aeolus, which was purposely built to construct offshore wind parks. The Aeolus will be assisted by a second vessel in 2022.

Siemens Gamesa Renewable Energy (SGRE) will be making the turbines for the wind farm, 207 metres high each. They will be equipped with state-of-the-art direct drive technology and their blades, measuring almost 82 metres in length, will deliver a swept area that is 18 % larger than the previous model along with 20 % higher annual power production compared to their predecessor.

The Saint-Brieuc wind turbines will be built in France, at Siemens Gamesa Renewable Energy's bespoke industrial facility, located in the port of Le Havre, where blades, nacelles and generators will be fabricated. The site includes a logistics zone dedicated to the installation of offshore wind farm projects and will lead to the creation of 750 jobs that will begin manufacturing in 2021.

On the other hand, submarine connection cabling systems will be provided by Prysmian Group — the world leader in cable manufacturer, energy solutions, telecom cables and systems with which Iberdrola worked at Wikinger and Vineyard Wind —, having signed a contract worth in the region of €80 million.

Prysmian will install and commission 90 km of 66 kV alternating current high.voltage connection cabling and three XLPE insulation hubs. The cable hubs will be manufactured at the group's centres of excellence in Montereau-Fault-Yonne and Gron (France) and will be assembled and finished in Nordenham (Germany), providing the French market with locally produced, state-of-the-art Prysmian cabling. The system is expected to be up and running by the end of 2022.

Following tests carried out in summer 2020, Ailes Marines has confirmed that it will bury all the cables between the wind turbines, which is a giant step forward for navigation safety and for the continuation of fishing activity within the park.

The substation has been awarded to the joint venture made up of Eiffage Métal and Engie Solutions. The first one will be in charge of the engineering and construction of the foundation and topside that houses the transformers and electrical equipment, while Engie Solutions will carry out final assembly work and commissioning tests.

The structure supporting this substation is formed by a jacket — measuring 63 m high and weighing 1,630 tons — and a topside measuring 55 m long, 31 m wide and 23 m high, with a total weight of approximately 3,400 tons. Fabrication works are scheduled to finish in early 2022.

Finally, Iberdrola has chosen GE Renewable Energy Grid Solutions to supply and install the main electrical equipment for the offshore substation, the last of the major supply contracts for this renewable energy complex.

GE Grid Solutions will take charge of the design, construction, installation and commissioning of the high-voltage electrical equipment, as well as the control and protection system for the substation. The company will design and manufacture the 72.5 kV and 225 kV gas-insulated switchgear (GIS) at their factory in Aix-les-Bains (France).

The substation control and protection systems will be designed at their centre of excellence in Montpellier (France) and the power transformers will be made at their Gebze plant in Turkey. Commissioning tests for the electrical equipment in the offshore substation are expected to take place during 2022.

A consortium led by Atos — in partnership with SeaRenergy, a leader in engineering, marine solutions, QHSE and personnel services for the offshore wind industry — will be responsible for implementing critical communication solutions and ensuring maritime coordination activities for the wind farm project.

Specifically, an operational maritime coordination centre will be established in the coastal city of Pleudaniel to coordinate, monitor and document all traffic in and around the construction area, operating 24 hours per day, seven days per week during the construction phase. Atos will also establish a unified critical communications platform that will enable helicopters, ships and operational teams working on the offshore wind farm to communicate seamlessly with each other and with the coordination centre, within and around the park.

Both systems will be retained after the construction phase and will support the wind farm throughout the operational phase, when all 62 turbines are working.

Once operational, in 2023, it will become the company's fourth such facility, after West of Duddon Sands, located in the Irish Sea; Wikinger, in the Baltic Sea; and East Anglia ONE, in the southern North Sea, one of the world's largest offshore wind farms.