IN Brief:
- The first operating Nordseecluster A turbine has supplied electricity to the German grid.
- Forty-four 15MW turbines will provide 660MW once the first phase is complete.
- Nordseecluster B will add 900MW, taking the combined development to approximately 1.6GW.
RWE has fed electricity from the first operating turbine at the Nordseecluster A offshore wind farm into the German grid.
The milestone follows installation of the project’s initial turbines and marks the beginning of staged testing and commissioning across the 660MW first phase. Full grid connection of Nordseecluster A is scheduled for early 2027.
Once complete, the development will comprise 44 Vestas turbines in the 15MW class. Electricity from the array will be collected through two offshore substations, where its voltage will be raised before transmission to the grid operator’s converter station and onwards to the mainland network.
Two substations are required because Nordseecluster A uses separate grid-connection points for different parts of the array. The arrangement divides the export infrastructure while allowing the two groups of turbines to connect through their respective offshore electrical systems.
RWE holds a 51% interest in Nordseecluster, with Norges Bank Investment Management owning the remaining 49%. RWE is responsible for construction and will operate the wind farms throughout their working lives.
The second phase, Nordseecluster B, will add 900MW through 60 further Vestas turbines. Foundation installation is scheduled to begin in 2027, turbine installation is planned for 2028, and commercial operation is expected in early 2029.
Together, the two phases will provide approximately 1.6GW and are expected to generate around 6.5TWh of electricity annually. The development combines four offshore sites — NC1, NC2, NC3, and NC4 — around 50km north of the German island of Juist.
Commissioning brings the complete electrical chain into service
First power marks the transition from offshore construction into live operation, although the wider array remains within a controlled commissioning sequence. Each turbine and electrical circuit must pass through energisation, functional testing, communications checks, protection verification, and controlled export before entering normal service.
Offshore substations, inter-array cables, export links, converter equipment, control systems, and onshore network assets must operate as a coordinated system. An incomplete interface or fault at any point can restrict output from generation equipment that is otherwise mechanically complete.
Germany connected 84 offshore turbines with combined capacity of 1,077MW during the first half of 2026, taking its operating offshore wind fleet to approximately 10.8GW. Nordseecluster A will add another substantial block of capacity as its turbines move through commissioning.
The scale of the project places sustained demands on offshore logistics, since installation vessels, service vessels, port facilities, cable-handling equipment, technicians, and specialist commissioning teams must be sequenced around weather windows and the readiness of each work package. Delays in one package can affect several others, particularly once energised equipment and construction activity begin operating alongside each other.
Nordseecluster’s supply chain includes offshore substations from Atlantique Offshore Energy, cables from Hellenic Cables, foundations from Dajin Offshore, foundation installation by Van Oord, and turbine transport and installation by DEME. Coordinating those packages is as important to delivery as the performance of any single component.
Larger turbine ratings reduce the number of machines required for a given project capacity, but each unit concentrates more output and places heavier demands on foundations, vessels, lifting systems, and replacement strategies. The 15MW-class machines selected for Nordseecluster form part of the sector’s move towards larger rotors and higher unit capacities, with corresponding effects on installation planning and component handling.
Grid readiness remains equally important because offshore wind projects can complete physical construction before every part of their connection system is available. Such mismatches can delay energisation or restrict exports, while Nordseecluster A’s two connection points and twin offshore substations make interface management a central part of the commissioning programme.
The development is intended to supply electricity for industrial energy arrangements as well as the wider German market. Large industrial users increasingly seek long-term renewable supply, although delivery still depends on transmission capacity, balancing resources, and the ability of the network to manage periods of high offshore output.
Nordseecluster B will extend those requirements into a second major construction cycle. Component production has begun ahead of offshore foundation work, allowing the two phases to share project knowledge while retaining separate installation, energisation, and commissioning programmes.
Operational experience from the first phase should inform the second, particularly around vessel scheduling, turbine handover, substation interfaces, cable testing, and the interaction between construction teams and live electrical systems. That learning will be most valuable where it can be transferred without compromising the separate technical and regulatory requirements of Nordseecluster B.
As additional turbines enter service, the project must demonstrate stable controls, reliable communications, coordinated protection, and secure transmission through both offshore substations. Full commissioning in early 2027 will turn the initial export milestone into a 660MW operating asset, before the second phase raises the combined development to approximately 1.6GW from 2029.
