Sumitomo Electric opens the UK's first HVDC subsea cable factory at Nigg

Sumitomo Electric opened its £350m subsea cable factory at the Port of Nigg in the Scottish Highlands on Monday 19 October. The Japanese company says it is the first plant in the UK able to make high-voltage direct current (HVDC) subsea cable, the type used to carry large amounts of power over long distances under the sea. When it signed the first supply deal for the plant in January 2025, Sumitomo said cable of this type had never been made in the UK.

The factory will make 525kV HVDC transmission cable with XLPE (cross-linked polyethylene) insulation, plus the inter-array cable that links turbines inside an offshore wind farm. It has 58,000 square metres of floor space on a 15-hectare site inside the Inverness and Cromarty Firth Green Freeport. Sumitomo puts direct employment at more than 200, with more than 400 jobs in total once suppliers are counted. Staff are being trained on a "train the trainer" model, with programmes run in Japan.

Sumitomo announced the plant in April 2023 and broke ground in May 2024. The Scottish Government put £24.5m into its construction, First Minister John Swinney said at the opening. The UK Government gave the freeport £25m of seed funding, according to the Scottish Secretary, Douglas Alexander.

Where the first orders come from

Two grid projects sit behind the investment.

The first is Sea Link, National Grid Electricity Transmission's planned link under the sea between Suffolk and Kent. Sumitomo won the contract to supply and install its 140km of HVDC cable in December 2025, working with Siemens Energy and the marine contractor Van Oord. Sumitomo said then that the cable would be made at Nigg and that construction was due to start in 2027.

The second is Shetland 2, a proposed second HVDC link between Shetland and the Scottish mainland for SSEN Transmission, which owns the grid in the north of Scotland. SSEN named Sumitomo and Van Oord preferred bidder in May 2024, signed a capacity reservation agreement in January 2025 and a longer framework agreement in July 2026. Under that framework, the two sides expect to sign a contract to make the Shetland 2 cable during 2026, subject to regulatory approval, with manufacturing at Nigg due to start in the second quarter of 2027. SSEN's managing director, Rob McDonald, called Shetland 2 the anchor for the factory at Monday's opening.

Neither link has consent yet

Both anchor projects are still in the planning system.

Sea Link is at the decision stage. The Energy Secretary (Secretary of State for Energy Security and Net Zero) has until 30 October 2026 to rule on National Grid's application for a development consent order, the Planning Inspectorate's project page shows. A consultation the Secretary of State opened with interested parties closes on 22 October.

Shetland 2 is earlier. SSEN's project page lists it at stage one of five, project assessment. Public feedback on two possible landfall sites on the Aberdeenshire coast is open until 6 November, and SSEN said in September that it expects to submit planning applications next year.

The factory has opened before either of its first two cable programmes has its permissions. Sumitomo's opening announcement did not give the plant's annual output or say when the first cable will run.

Who else makes the cable

Two other big UK HVDC cable orders this year went to European makers. In February 2026, National Grid and SP Energy Networks gave Prysmian a £2bn contract for Eastern Green Link 4 between Fife and Norfolk: more than 640km of cable, including 530km under the sea, for a link due to run in 2033. Prysmian also supplies Eastern Green Link 1. In March 2026, NKT signed a contract worth more than €2.2bn with National Grid and SSEN Transmission for Eastern Green Link 3, about 680km of cable, due to be commissioned at the end of 2033. NKT said it was the largest single order in its history.

The other plan for a British HVDC cable plant has shrunk. XLCC, which had proposed a factory at Hunterston in Ayrshire with 1,200 jobs, renamed itself Aquora in January and moved to cable installation first, Energy Voice reported on 26 January. Its executive chairman, Lewis Gillies, said the factory had been scaled back by about half and that its location was still to be decided. Aquora plans to spend about £350m on installation, with a cable-laying ship due in the first half of 2029, before about £650m on manufacturing.

Gillies put demand for cable in Europe at 100,000km over the next decade, citing 4C data, against historic supply of about 3,500km a year.

What the grid owners are spending

SSEN Transmission says it plans to invest about £29bn over the next five years. National Grid's Carl Trowell said at the opening that the company had set up more than £28bn of UK supply chain contracts. McDonald said that greater certainty on future grid investment and planning decisions could bring more factories like Nigg.

Nigg is the first HVDC cable plant on British soil, in a UK market where the largest recent orders have gone to Prysmian and NKT. The first planning decision on its order book, for Sea Link, is due by 30 October.

Sources:

Sumitomo Electric: opening ceremony, 19 October 2026

Highlands and Islands Enterprise, 19 October 2026

BBC News, 19 October 2026

Sumitomo Electric: Sea Link contract, 11 December 2025

Sumitomo Electric: Shetland 2 capacity reservation agreement, 23 January 2025

Sumitomo Electric: groundbreaking and preferred bidder, 14 May 2024

Sumitomo Electric: framework agreement, July 2026

SSEN Transmission: framework agreement with Sumitomo Electric and Van Oord, 9 July 2026

Planning Inspectorate: Sea Link (EN020026), updated 19 October 2026

National Grid: Sea Link project page, checked 20 October 2026

SSEN Transmission: Shetland HVDC Link 2, update of 4 September 2026

National Grid: EGL4 Prysmian contract, 2 February 2026

NKT: company announcement no. 5, EGL3, 4 March 2026

Find a Tender: LT14 Western Isles HVDC Cables award, concluded 16 January 2026

Energy Voice, 26 January 2026