IN Brief:
- RWE has installed 22 of the 44 turbines planned for the 660MW Nordseecluster A offshore wind farm.
- Turbine testing and commissioning are progressing alongside installation after first electricity reached the German grid in July.
- Nordseecluster B will add another 900MW, taking the two-phase development to approximately 1.6GW from 2029.
RWE has installed the 22nd turbine at its 660MW Nordseecluster A offshore wind farm, taking the first phase of the German North Sea development to the halfway point in its turbine installation programme.
The project will use 44 Vestas turbines rated at up to 15MW each, installed around 50km north of the German island of Juist. DEME’s installation vessel Norse Wind is handling turbine transport and installation, while completed machines are moving through testing and commissioning as construction continues elsewhere in the array.
All 44 turbines are scheduled to be installed by the end of 2026, with the complete first phase expected to be connected to the grid in early 2027. The first Nordseecluster A turbine exported electricity in July, allowing electrical commissioning and mechanical installation to proceed in parallel.
That overlap makes the second half of the construction programme more complicated than the turbine count alone suggests. Once part of an offshore wind farm becomes electrically live, installation crews are working alongside energised cables, substations, protection systems, and turbine controls, requiring tightly managed interfaces between marine construction and high-voltage operations.
Individual turbine completion is therefore only one part of the sequence. Inter-array cable circuits have to be energised, communications established, protection settings proven, control systems integrated, and each machine handed into the wider wind-farm control architecture before its output can be treated as dependable generation.
Nordseecluster A is the first phase of a two-stage development with combined capacity of approximately 1.6GW. Nordseecluster B will add another 900MW through 60 Vestas turbines, with foundation production already under way and offshore foundation installation planned during 2027.
Turbine installation for the second phase is scheduled during 2028, ahead of commercial operation from early 2029. That leaves RWE managing two different stages of the same development at once: electrical completion and commissioning for Nordseecluster A, alongside component production and construction preparation for Nordseecluster B.
RWE holds a 51% interest in Nordseecluster, while Norges Bank Investment Management owns the remaining 49%. RWE is responsible for construction and subsequent operation, giving it direct responsibility for carrying engineering and commissioning experience from the first phase into the second.
The combined development is expected to generate around 6.5TWh of electricity annually once both phases are operating. Part of that output is already tied to long-term industrial and technology demand, including a 110MW power purchase agreement with Amazon covering electricity from Nordseecluster B.
The commercial arrangements sit behind an increasingly demanding physical delivery programme. Large offshore wind projects need turbine manufacture, foundations, substations, cables, vessels, ports, grid infrastructure, and commissioning teams to arrive in the correct sequence; a delay in one package can leave substantial investment offshore without a complete route to commercial generation.
Installing larger turbines reduces the number of machines required for a given project capacity, but it increases the demands placed on each lift and transport operation. A 15MW-class turbine concentrates more generating capacity into the tower, nacelle, blades, foundation, and electrical connection, requiring vessels and handling equipment capable of dealing with correspondingly larger components.
Weather remains another constraint. Offshore installation campaigns are built around workable wind and sea conditions, with poor weather capable of interrupting lifts, vessel transfers, cable activity, and technician access even when components and crews are otherwise ready.
The first 22 installations show that the marine campaign is progressing, but the remaining turbines still have to be completed before winter conditions narrow some operating windows. Keeping the installation programme aligned with electrical commissioning will be important if the project is to maintain its early-2027 grid-connection target.
Nordseecluster A has already passed several major infrastructure milestones. Both offshore substations were installed before turbine construction accelerated, inter-array cable work has progressed across the site, and first power demonstrated that part of the export chain can carry electricity into the German system.
Full commercial operation requires that performance across the entire 660MW array. Every turbine and cable circuit must be commissioned, protection and communications have to function consistently, and the offshore electrical infrastructure must cope with increasing generation as successive machines are handed over.
The second phase will then repeat much of that sequence at greater capacity. Shared suppliers and project experience should provide opportunities to carry engineering lessons forward, although Nordseecluster B remains a separate construction and energisation programme with its own weather, logistics, grid, and commissioning risks.
RWE is building Nordseecluster alongside other major European offshore projects including Sofia in the UK, Thor in Denmark, and OranjeWind in the Netherlands. Together with Nordseecluster, those schemes create sustained demand for turbines, installation vessels, cables, foundations, substations, ports, and specialist offshore labour.
For Nordseecluster A, the next milestones are considerably closer. Twenty-two turbines are installed, live commissioning is already under way, and another 22 machines have to move through offshore installation and electrical completion before the project becomes a fully operating 660MW power station in early 2027.
