In the French shipyard of Chantiers de l'Atlantique in Saint-Nazaire, two offshore substations have been completed. The platforms form the operational heart of the North Sea Cluster A. This offshore wind project is being constructed by RWE (51 percent) and Norges Bank Investment Management (49 percent) together off the German coast.
Each substation is about 40 meters long and 22 meters high. The first platform weighs around 1,800 tonnes, the second about 2,500 tonnes. Both are to be transported to the construction site by barge by the end of February. This site is located about 50 kilometers north of the island of Juist. According to the company, the transport takes about eight days. The foundations for both substations have already been installed.
Substations collect and transform the electricity
In the park's internal substations, the electricity generated by the wind turbines is collected. The voltage is increased to transmit the electricity to the grid operator's converter station. From there, it reaches the mainland. The substations are also equipped for remote monitoring and control.
"It is impressive to see these two large substations up close – ready for installation in the German North Sea," says Tobias Keitel, CTO of RWE Offshore Wind. "With this 1.6-gigawatt cluster, RWE significantly expands its offshore wind portfolio and contributes to creating a reliable, sustainable, and affordable energy system."
Frédéric Grizaud, Senior Vice President of the Marine Renewable Energies division at Chantiers de l'Atlantique, said: "This project demonstrates the international competitiveness of the French offshore wind industry, confirms our position as a leading player in a rapidly growing sector, and underscores our contribution to European energy independence."
North Sea Cluster A is expected to go online in early 2027
The construction work for the North Sea Cluster A is proceeding according to plan. The installation of the foundations was completed at the end of 2025. Currently, the park's internal cables are being laid. The installation of the 44 wind turbines is scheduled to begin in the summer of 2026. After full commissioning in early 2027, North Sea Cluster A is expected to have a total capacity of 660 megawatts (MW).
The second expansion stage, North Sea Cluster B, is expected to contribute an additional 900 MW with 60 wind turbines from early 2029. The production of the foundations has already begun. According to RWE, the entire North Sea Cluster with 1.6 gigawatts of capacity can theoretically supply around 1.6 million German households. RWE is responsible for the construction and operation throughout the entire lifecycle of the offshore wind farms.
