Seaway7 Starts Cable-Laying at Ørsted’s 2.9 GW Hornsea 3
Seaway7 has begun installing inter-array cables at Ørsted‘s Hornsea 3 offshore wind farm in the UK North Sea, the companies said on November 13, using the cable-laying vessel Seaway Phoenix with support from the walk-to-work vessel Seaway Moxie. The campaign covers roughly 500 kilometres of cable that will connect Hornsea 3’s turbines to two offshore converter stations — a milestone in a project that, at 2.9 GW, is set to become the largest single offshore wind farm built to date.
Five years of work reach the array
“After almost five years of hard work we’ve reached the key moment for our array cables,” said Luke Bridgman, Ørsted’s Managing Director for Hornsea 3. The inter-array cables being laid now carry electricity from each of the 197 Siemens Gamesa SG 14-236 DD turbines that will populate the site to the converter stations, where it is stepped up for transmission to shore. Hellenic Cables and Prysmian are supplying the cables, while JDR Cable Systems handles testing and termination of the array connections — a multi-contractor supply chain typical of a project at this scale.
Hornsea 3 is Ørsted’s first European project to use high-voltage direct current (HVDC) transmission, a technology that cuts losses over the long distance between the far-offshore turbines and the UK coast compared with the alternating-current systems used on most shallower wind farms. It is also the third gigawatt-scale development in Ørsted’s Hornsea zone, following Hornsea 1 (1.2 GW, operational since 2020) and Hornsea 2 (1.3 GW, operational since 2022). Together, the three projects will bring more than 5 GW of offshore wind capacity onto a single stretch of the North Sea — among the largest concentrations of offshore wind anywhere.
A familiar contractor returning to the zone
Seaway7, part of the Subsea7 group, previously installed the inter-array cabling for both Hornsea 1 and Hornsea 2, giving it direct experience with the same seabed conditions and client before taking on the larger Hornsea 3 scope. The start of cable-laying follows earlier 2026 work preparing the site, including seabed inspection and trenching, and comes as Hornsea 3’s broader construction programme — foundations, turbine installation and the export cable system to shore — continues in parallel.
The project’s progress matters beyond Ørsted’s own balance sheet. Hornsea 3 is one of the larger single contributors to the UK’s offshore wind pipeline as the country works toward its clean power targets for the end of the decade, and inter-array cable installation is typically one of the last major offshore campaigns before a wind farm can begin exporting power — meaning this stage of work puts Hornsea 3 closer to first electricity than to first steel in the water.
A steadier market for Ørsted
Ørsted’s push to finish Hornsea 3 comes after a difficult stretch elsewhere in its portfolio. The Danish developer cancelled two major US offshore wind projects, Ocean Wind 1 and Skipjack Wind, in 2023 after cost inflation made them uneconomic, and took billions of dollars in impairments across its American business. The UK has been a comparatively steadier market for the company, where Hornsea 1 and Hornsea 2 are both already supplying the grid and Hornsea 3 is now moving through its final major offshore campaigns. Britain’s government has made expanding offshore wind central to its target of a largely decarbonised power system by the end of the decade, which makes a project the size of Hornsea 3 — bigger than Hornsea 1 and Hornsea 2 combined — one of the single largest contributors to that goal.
Sources
- Offshore Energy, “Seaway7 begins inter-array cable installation at Ørsted’s Hornsea 3 offshore wind farm,” November 13, 2026 — vessel names, cable length, turbine count, capacity, Luke Bridgman quote, cable suppliers. Link
Illustrative image. Photo: Capmat007, CC BY-SA 4.0, via Wikimedia Commons — source
