UK's first HVDC subsea cable factory opens in Scotland

On 19 October, at the Port of Nigg on Scotland’s north-east coast, Sumitomo opened a factory the UK had never had: a plant able to make high-voltage direct current (HVDC) subsea cables. The opening ceremony mixed Japanese and Scottish cultural elements, a nod to the company’s Japanese ownership and to the Highland site. The building cost £350M and covers 15 hectares, with 58,000 m² of floor space, inside the Inverness and Cromarty Firth Green Freeport boundary.

HVDC is a way of sending electricity over very long distances as direct current rather than alternating current, the form used in most homes. For very long links, it loses less power along the way. Until now, the UK bought these cables abroad. Sumitomo noted that the country had been one of only two G7 members without manufacturing capability for them. The plant will produce 525kV HVDC subsea transmission cables, along with offshore AC cables, to carry power from Scottish wind farms to places of demand elsewhere in the UK.

The project has backers and customers already lined up. The Scottish Government contributed £24.5M to construction. Sumitomo said it has received early orders from National Grid’s SeaLink project and from SSEN Transmission’s proposed Shetland 2 project. National Grid’s executive president of global capital, Carl Trowell, said the company has awarded Sumitomo Electric the contract to supply the HVDC cable for SeaLink, and that National Grid has placed more than £28 billion of UK supply chain contracts overall. Shetland 2 is still at the proposal stage.

For workers, the immediate gain is employment: Sumitomo expects about 250 direct jobs and more than 400 roles across the wider UK supply chain. SSEN Transmission, whose managing director Rob McDonald called the opening “a landmark moment”, put the figure at at least 200 jobs and said it is investing around £29bn over the next five years in the grid. The sources do not say when the first cables will leave the factory, nor how quickly the wider supply chain will fill. What the plant does change is the path for offshore wind: a UK-made link for the cables that connect it to homes and businesses elsewhere in the country, instead of a dependence on foreign suppliers.