Saint-Brieuc offshore wind farm electrical substation installed

July 8, 2022
Ailes Marines announced the completion of the installation of the electrical substation of the Saint-Brieuc offshore wind farm by the Saipem 7000 vessel.

Offshore staff

PARIS, France  Ailes Marines, a company 100% owned by the Iberdrola Group, announced the completion of the installation of the electrical substation (OSS) of the Saint-Brieuc offshore wind farm.

Saipem has installed the first electrical substation at sea in Brittany. It is the second substation installed on an offshore wind farm in France.

The installation operation was carried out by the Saipem 7000 vessel. This crane vessel concentrates a capacity and technology particularly suitable for this type of operation.

The installation of the substation was carried out in two stages. After the installation of the jacket foundation (1,630 tons) on its four piles, the topside (3,400 tons) was installed on its foundation on July 6. 

The foundation of the electrical substation is 63 m high for a total weight of 1,630 tons. The topside is 55 m long, 31 m wide and 23 m high, for a total weight of about 3,400 tons.

The substation consists of two elements manufactured separately and assembled at sea:

  1. The lower part, the jacket foundation fixed to the seabed by piles; and
  2. The upper part, the topside, that houses all the electrical equipment.

Smulders, a subsidiary of Eiffage Métal, carried out the engineering and manufacture of the jacket foundation and the metal structure of the topside.

Equans designed and equipped the low-voltage electrical part of the topside, including the auxiliary systems and the integration of medium and high-voltage equipment provided by GE Grid Solutions.

The jacket and topside were preassembled by Smulders at the Hoboken shipyard near Antwerp, Belgium. The final assembly of the topside was carried out at the Equans shipyard in Hoboken. The final assembly of the jacket foundation was carried out at the Heerema shipyard in Vlissingen in the Netherlands.

Connection to the operational electricity grid in 2023

Technicians from Equans and Smulders will work on the OSS for commissioning. Once operational, the fully automated substation will be remotely controlled and controlled. Technicians will intervene for maintenance operations via personnel transport vessels.

The substation will collect the electricity produced by the 62 wind turbines by raising the electrical voltage through power transformers. The electricity will then be transported by Réseau de Transmission d'Electricité (RTE) via two export cables with a voltage of 225 kV.

The connection by RTE of the electrical substation to the export cables to the mainland will be operational before the installation of the wind turbines planned for 2023.