A single bundled cable now links the North Sea’s mightiest wind farm to millions of homes. The scale of what’s coming is hard to overstate.

A bundled cable assembly carrying two high-voltage power lines and a fibre optic data strand was pulled from the North Sea seabed onto the Norfolk coast on March 26, physically connecting the world’s largest offshore wind farm to Britain’s electricity network for the first time. The operation established the initial transmission route for Hornsea 3, a 2.9-gigawatt project that will supply clean electricity to more than 3.3 million homes across the United Kingdom.

The cable pull is the most tangible construction milestone yet for the £8.5 billion development, which sits roughly 120 kilometres off the Yorkshire coast and has been in preparation since 2018. Hornsea 3 is expected to be fully operational by the end of 2027. At that point it will generate enough power to meet the average daily needs of a population larger than Greater Manchester, Liverpool, and Leeds combined.

That scale arrives at a critical moment for British energy infrastructure. The UK currently runs about 15 gigawatts of offshore wind capacity. Hornsea 3 alone forms a large piece of the government’s target of 50 gigawatts by 2030. Duncan Clark, Head of Ørsted UK and Ireland, called the project “a cornerstone in achieving the UK government’s climate and clean energy targets while increasing energy independence and creating local jobs.” It will, he added, “make a significant contribution towards the UK Government’s ambitious target of 50 GW of offshore wind by 2030 and net-zero by 2050.”

Inside the Export Cable

The export cable bundles two high-voltage direct current cables with a fibre optic strand that sends operational data back to the control centre. Packaging them together cuts the number of separate laying runs and shields each component during installation. Belgian marine contractor Jan De Nul Group is handling the offshore work, tasked with laying a total of 680 kilometres of export cable before the end of 2026.

Once the turbines start spinning, electricity will move through the offshore cable to the coastline, then transfer to an onshore line running more than 50 kilometres underground to a converter station at Swardeston in Norfolk. There the direct current gets transformed for the national grid. The buried onshore route was chosen to limit surface disruption across the Norfolk countryside, Offshore Wind Biz reported.

NKT, the project’s cable supplier, started manufacturing three years ago and expects to finish production this summer. Keeping that timeline aligned with Jan De Nul’s installation schedule, which runs through late 2026, is one of the tighter logistical challenges on the project. A delay in any single piece echoes across the entire build.

A Converter Station Built Across Continents

Two offshore converter stations are going in at the Hornsea 3 site. The jacket foundation for the first one left the Dutch port of Vlissingen, Inspenet reported. It stands 54 metres tall, weighs roughly 3,500 tonnes, and is built to take sustained open North Sea conditions for its full working life.

The upper section of that same station traced a far longer route, travelling more than 13,000 nautical miles from Thailand to Norway before heading to the installation point. That module alone crossed more ocean than most commercial vessels do in a year.

Heerema’s crane vessel Sleipnir placed the first jacket, while Hitachi Energy and Aibel contributed high-voltage electrical equipment and offshore engineering expertise. A first complete offshore substation was standing by the end of March 2026.

Where Hornsea 3 Fits in the Hornsea Zone

Hornsea 3 is the third gigawatt-scale project Ørsted has built in the North Sea’s Hornsea zone, and the jump in size shows how fast fixed-bottom offshore wind engineering has moved. Hornsea 1 delivered 1.2 gigawatts. Hornsea 2 delivered 1.3 gigawatts. The third project outmatches both predecessors combined inside a single farm boundary.

The project is jointly owned by Ørsted and funds managed by Apollo, after a late 2025 deal in which Ørsted sold a 50 percent stake for around 5.2 billion euros. Apollo’s entry brought capital at a moment when offshore construction costs were rising across the sector.

Ørsted, based in Denmark, operates more than 18 gigawatts of installed renewable capacity across Europe, North America, and Asia Pacific. The Hornsea zone, as Ørsted has detailed in its own insights on the project, stays central to its UK plans.

Turbines, Jobs, and What Comes Next

Hornsea 3 will use Siemens Gamesa’s 14-megawatt turbines, among the most powerful commercial offshore machines available. Foundation monopiles have already arrived from Spain and China, and installation is approaching as the programme shifts into its next phase.

The project is expected to support up to 5,000 construction jobs and roughly 1,200 permanent roles once it begins operating. Operations will run from Grimsby, a Humber Estuary town that has built up deep infrastructure around North Sea wind operations over the past decade. The region has grown into a hub for offshore wind expertise and long-term employment.

With the first cable ashore and the first substation standing, the focus now turns to finishing foundation installation and then deploying turbines. NKT will wrap up cable production this summer to stay in step with Jan De Nul’s installation schedule. Hornsea 3 remains on track to reach full operation around the end of 2027.

Source: Indian Defence Review