A ceremony held today at the Chantiers de l’Atlantique shipyard in Saint-Nazaire, France, marked the successful completion of the design, construction and integration phases of two offshore electrical substations. These substations will become the operational heart of Phase A of the Nordseecluster offshore wind project, a collaboration between RWE (51%) and Norges Bank Investment Management (49%), which is currently under construction off the German coast.
Each topside is approximately 40 metres long and 22 metres high. The first topside weighs about 1,800 tonnes, while the second comes in at around 2,500 tonnes. Both large-scale structures will depart from Saint-Nazaire by the end of the month. The units will be transported by barge to their installation site in the North Sea, around 50 kilometres north of the German island of Juist, on a voyage lasting around eight days. The foundations for the two substations have already been installed.
Tobias Keitel, Chief Technology Officer at RWE Offshore Wind: “It is impressive to see these two large topsides ready for installation in the German North Sea. With the foundations already in place, everything is prepared for the upcoming ‘wedding at sea’ — the moment when the topsides are successfully installed on the foundations. My sincere thanks go to Chantiers de l’Atlantique for their outstanding craftsmanship, as well as to our valued partner Norges Bank Investment Management, the entire RWE team, and everyone involved in bringing the Nordseecluster to life. With this 1.6-gigawatt cluster, RWE is significantly expanding its offshore wind portfolio and helping to deliver a reliable, clean, and affordable energy system.”
Frédéric Grizaud, Senior Vice President Marine Renewable Energies business unit at Chantiers de l’Atlantique: “We would like to thank RWE for their confidence in us. Delivering two offshore substations simultaneously is a major achievement for our teams and reflects both their commitment and technical expertise. This project demonstrates the international competitiveness of the French offshore wind industry, confirms our position as a leading player in a rapidly expanding sector, and highlights our contribution to European energy sovereignty.”
The Nordseecluster substations will collect electricity generated by the turbines, increase the voltage and transmit the power to the converter station of the grid operator. From this converter station the electricity flows to shore. The Nordseecluster substations are also equipped to gather operational data from the wind farms and to enable remote monitoring and control from land.
Construction of Nordseecluster A progressing according to plan
The offshore works on Nordseecluster A are proceeding well with foundation installation completed at the end of last year, cable-laying currently underway and installation of the 44 wind turbines to begin in summer 2026.
After full commissioning in early 2027, Nordseecluster A will have a total capacity of 660 megawatts (MW). The second expansion stage, Nordseecluster B, for which fabrication of foundations has already begun, will contribute an additional 900 MW through its 60 wind turbines, which will commence commercial operation in 2029.
The Nordseecluster will be able to generate enough green electricity to supply the equivalent of around 1.6 million German households. RWE is responsible for the construction and operation of the Nordseecluster offshore wind farms throughout their entire life cycle.
RWE is a leading global player in offshore wind
RWE is one of the world's leading players in the offshore wind sector and has more than 20 years of experience in the development, construction, and efficient operation of offshore wind farms. In addition to Nordseecluster, the company is currently implementing three other large offshore wind projects: Sofia in the UK (1.4 GW), Thor in Denmark together with Norges Bank Investment Management (1.1 GW), and OranjeWind in the Netherlands in collaboration with TotalEnergies (795 MW).
Further information on the Nordseecluster offshore wind project can be found here.
Images of the event for media use are available here (Credit: Chantiers de l’Atlantique)
Images of the substation foundation installation for media use are available at the RWE Media Centre (Credit: RWE / Photographer: Matthias Ibeler)
Technical characteristics of the Nordseecluster A offshore substations:
