The electrical substation for the Saint-Brieuc offshore wind farm has been successfully installed The electrical substation for the Saint-Brieuc offshore wind farm has been successfully installed


The electrical substation for the Saint-Brieuc offshore wind farm has been successfully installed

July 08th '22

Saipem 7000 installs Brittany's first offshore electricity substation

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

This unusual installation operation was carried out by the Saipem 7000, one of the largest lifting vessels in the world, belonging to the Italian company Saipem. This crane ship has the capacity and technology particularly suited to this type of operation.

The substation was installed in two stages. After the installation of the jacket foundation (1630 tonnes) on its 4 piles, the topside (3400 tonnes) was installed on its foundation during the night of 6 July.

The OSS, a key part of the wind farm

The substation is made up of two separately manufactured components that are assembled at sea: the lower part, the "jacket" foundation, fixed to the seabed by piles, and the upper part, the "topside", which houses all the electrical equipment.

The foundation of the electricity substation is 63 metres high and weighs a total of 1,630 tonnes. The topside is 55 metres long, 31 metres wide and 23 metres high, with a total weight of approximately 3,400 tonnes.

Smulders (a subsidiary of Eiffage Métal) carried out the engineering and manufacturing of the jacket foundation and the steel structure of the topside.

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

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

Connection to the electricity grid operational in 2023

Technicians from Equans and Smulders will work on the OSS to commission it. Once operational, the fully automated substation will be remotely controlled and monitored. Technicians will be available for maintenance operations via personnel vessels.

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

The connection by Réseau de Transport d'Electricité (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.

Emmanuel Rollin, Director of Offshore France at Iberdrola, was pleased with this achievement: "With the successful installation of the electrical substation, the Saint-Brieuc wind farm is now more than ever at sea. This operation, which was completed in a relatively short timeframe, is a testament to the expertise and involvement of all the teams at Ailes Marines, its contractors and local stakeholders, who have been involved in the development and implementation of this ambitious project for over 10 years. By the end of 2023, the Côtes d'Armor department, with the Saint-Brieuc offshore wind farm, will be the leading contributor of renewable energy in Brittany, producing the equivalent of 9% of the region's total electricity consumption."


Photo credits Saipem & Ailes Marines