UK’s fourth subsea electricity superhighway to sport Siemens Energy converter stations

July 17, 2025, by Nadja Skopljak

Siemens Energy has been appointed as the preferred bidder for the delivery of two high-voltage direct current (HVDC) converter stations for the fourth out of five subsea electricity superhighways between Scotland and England.

This news for the Eastern Green Link 4 (EGL4) project comes as National Grid and SP Energy Networks signed a joint venture to deliver the project, marking the third subsea electricity superhighway to be delivered by the two transmission owners.

EGL4 is an HVDC electricity transmission interconnector that will connect Fife in Scotland with Norfolk in England, which will be able to transmit up to 2 GW of clean, renewable energy, enough to power around 1.5 million homes.

The link will consist of a 530-kilometer HVDC subsea cable between Kinghorn, Fife, and South Humber, Lincolnshire, a 14-kilometer underground cable from Kinghorn to a new converter station at Westfield, near Ballingry, Fife, as well as a 100-kilometer underground cable from South Humber to a new converter station near Walpole, Norfolk.

Siemens Energy was also recently awarded a place on National Grid’s £59 billion HVDC supply chain framework and SP Energy Networks £5.4 billion Strategic Agreement to deliver the required works and equipment needed for key energy projects across the UK.

EGL4 is one of five proposed subsea links between Scotland and England being delivered through joint ventures with Scottish transmission owners. Together, the five links will be capable of powering up to 10 million homes.

First steps being taken to bring UK’s fifth subsea electricity superhighway to life

Project & Tenders

The second stage of public consultation at both ends of the link was recently concluded, with the feedback set to inform the project’s development, which includes the planning application in Scotland, expected during late summer and an application for development consent to the Planning Inspectorate in England during 2026.

Construction is expected to begin in 2029, with the link becoming operational in 2033.

“Reaching preferred bidder stage is a key milestone for EGL4 and a sign of the progress being made on this vital infrastructure project. Siemens Energy brings strong expertise in HVDC converter station delivery and will be a critical partner as we prepare to build this subsea superhighway,” said James Goode, Project Director for Eastern Green Link 4 at National Grid.

“EGL4 will help create the capacity our electricity system needs for the future, connecting clean, home-grown energy to homes and businesses and strengthening the UK’s energy security.”