The 496MW Bay of Saint-Brieuc wind power project is located 16.3km off the coast of Saint-Brieuc Bay in Brittany in north-western France.
The windfarm is the first large-scale offshore windfarm in Brittany and one of the largest commercial-scale offshore wind projects in France.
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The project was developed by Iberdrola’s affiliate Ailes Marines who is also the operator. Iberdrola gained 100% ownership of Ailes Marines, following the acquisition of the remaining 30% capital from Avel Vor in March 2020.
The offshore windfarm was developed with an investment of approximately €2.4bn ($2.7bn). Construction work for the project began in 2021 and the first power was produced in July 2023.
The full commissioning work is expected to continue through the first quarter of 2024.
The wind power plant will generate 1,820GWh of clean energy a year when it becomes fully operational, which will be sufficient to meet the energy requirement of 835,000 homes.
Location
The Saint-Brieuc offshore windfarm is located in the Bay of Saint-Brieuc, 16.3km off the coast of Brittany. The windfarm covers an area of approximately 75km² in the English Channel.
Saint Brieuc offshore windfarm makeup
The Saint Brieuc offshore windfarm is equipped with 62 units of SG 8.0-167 DD offshore wind turbines configured in seven rows.
With a capacity of 8MW each, the 207m-high turbines are equipped with direct drive technology, which uses fewer moving parts compared to geared machines. The turbine blades are 82m long with a swept area of 18%.
The 225kV offshore cable system involves two 33.5km three-core cable with a hybrid armouring solution. A fibre optic system is also incorporated into the design to facilitate remote monitoring of the cable link and data transmission between the offshore windfarm and the land base. The onshore section of the power export cable comprises a 93km-long 225kV single-core cable.
The submarine connection cabling system comprises of 90km-long 66kV AC high-voltage connection cabling and three cross-linked polyethene insulation hubs. Connection to the onshore grid is via two export cables, a 225kV submarine link and a 225kV land link.
The electricity generated at the windfarm is evacuated through a 225kV export cable system to Caroual beach, in Erquy from where it connects into the grid via the Doberie substation located in Hénansal.
Saint Brieuc offshore windfarm construction details
The offshore substation features a 63m-high jacket with a topside weighing 3,400 tonnes. The 55m-long topside is 31m wide and 23m high. The topside and the jacket was loaded out in June 2022. The offshore installation of the substation was completed in July 2022.
Van Oord started the installation of the first of the 62 jacket foundations at the windfarm site, using Aeolus in May 2021.
In July 2021, Bravenes, a subsea rock installation vessel, arrived at the project site for the installation of riprap on the seabed to stabilise and protect subsea cables and the pin piles at the site.
The offshore and onshore export cables were laid by the CS Skagerrak vessel, and the cables were trenched into the seabed, using a specialised Capjet system.
The company started the first wind turbine installation out of the 62 wind turbines in May 2023. It was installed on position number SB44, located on the northern part of the project site.
First power from the windfarm was produced in July 2023, marking the first clean energy production through an offshore windfarm for the first time in Brittany.
The installation of the jacket foundations was completed in October 2023 while wind turbine installations were completed in December 2023.
Contractors involved
Siemens Gamesa Renewable Energy 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 contract for the construction and assembly of jackets and their corresponding piling, including transport and installation of the jacket foundations and the offshore substation.
Prysmian was contracted to provide the submarine connection cabling systems under an €80m contract. The links for grid connection were designed, built, and maintained by French transmission system operator RTE.
Nexans was awarded a €115m contract by RTE to provide the export cables including inspection, maintenance and repair 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 was also involved in the layout of electrical, heating, ventilation and air-conditioning, piping, cable trays, and fire protection equipment for the windfarm.
NKE Instrumentation provided oceanographic buoys for monitoring the construction work. It also collaborated with local partners for manufacturing floats, data processing, and chartering of vessels.
SNC-Lavalin company Atkins was selected to deliver the front-end engineering design of 62 wind turbine jacket structures for the project. AXYS WindSentinel was selected to provide the assessment of offshore wind for the project site.
The French companies Eiffage Metal and ENGIE Solutions received the contract for the construction of the windfarm’s electrical substation in September 2020.
In December 2020, Atos was selected to provide mission-critical communication solutions and to ensure marine coordination activities at the project site.
Smulders and its consortium partner EQUANS were awarded a contract to construct an offshore substation for the project. The consortium also provided the engineering, construction, installation, commissioning and testing of the substation.
