Offshore wind farm
Start of Construction
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 wind farm will be 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 more than 2,000 direct jobs and thousands of indirect jobs. Construction work for the project began in 2021 and is scheduled for completion in 2023.
The wind power plant will generate 1,820GWh of clean energy a year, which will be sufficient to meet the energy requirement of 835,000 homes.
Saint Brieuc offshore wind farm make-up
Saint Brieuc wind farm will cover an area of approximately 75km² in the English Channel and contain 62 SG 8.0-167 DD offshore wind turbines configured in seven rows.
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 onshore via two export cables, a 225kV submarine link and a 225kV land link.
The electricity generated at the wind farm will be evacuated by Réseau de Transport d’Electricité (RTE) through the 225kV export cable system.
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. AXYS Technologies’ FLiDAR WindSentinel buoy, a wind resource assessment system, was deployed in Britanny to evaluate the wind resource and anticipated energy production at the offshore wind farm.
The optimum orientation of the wind turbines for the highest possible energy yield was determined using a laser imaging detection and ranging (LIDAR) system. Offshore operations 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 the steel lattice structure.
Van Oord started the installation of the first of the 62 jacket foundations at the wind farm site, using Aeolus in May 2021 following extensive preparations. As part of its contract to transport and install the jacket foundations, the company will install a total of 190 pin piles, including three pin piles each for each of the turbines and four foundation pin piles for the offshore substation.
The harsh weather conditions in the area combined with extremely strong currents will enable offshore operations only between March and October.
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 will be laid by the 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.
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 the jacket foundations and the offshore substation.
Prysmian Group was contracted to 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.
SNC-Lavalin Group company Atkins was selected to deliver the front-end engineering design (FEED) 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 Métal and ENGIE Solutions received the contract for the construction of the wind farm’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. The company agreed to establish a marine coordination centre in Brittany, France to coordinate, monitor and document all the traffic in and around the construction area and will operate 24/7 during the construction stage.