National Grid has secured development consent for the 2GW Sea Link electricity connection between Suffolk and Kent, clearing the 138km project to move into detailed delivery planning ahead of an expected construction start in early 2027.
The Secretary of State granted the Development Consent Order on 30 October after an examination of National Grid Electricity Transmission's application. The Planning Inspectorate confirmed the decision after the application was submitted on 27 March 2025, accepted the following month and examined before a recommendation went to ministers on 30 July 2026.
Sea Link will provide a new high-voltage connection between East Anglia and the South East, increasing the amount of electricity that can move between the two regions. National Grid says the scheme is expected to enter construction in early 2027 and complete in 2031, subject to detailed construction planning.
Illustration of National Grid's Sea Link electricity connection between Suffolk and Kent, including the offshore HVDC cable route. Illustration: London Construction Magazine
138km link combines offshore cable and converter stations
The project comprises a 138km high-voltage link, most of it offshore, with converter stations and underground cable infrastructure at both ends. The offshore HVDC section will run between the Suffolk coast and Pegwell Bay in Kent, with the Planning Inspectorate describing the subsea cable section as approximately 130km long.
In Suffolk, a new converter station will be built within 5km of the proposed Friston substation. Underground HVAC cables will connect the converter station to Friston, while underground HVDC cables will run from the converter station to the coast before joining the offshore cable.
The Kent side will bring the offshore cable ashore at Pegwell Bay and continue underground to a new converter station near the existing Richborough substation. An approximately 1km HVAC connection will then connect the scheme into the existing transmission network.
Ofgem's September project assessment consultation described the converter station locations as Saxmundham in Suffolk and Minster in Kent. Sea Link sits within the Accelerated Strategic Transmission Investment programme under the RIIO-3 price-control framework.
Siemens and Sumitomo are already in the delivery chain
National Grid has appointed Siemens Energy to build the converter stations in Kent and Suffolk. The stations will convert electricity between alternating current used by the onshore transmission network and direct current used across the long-distance cable connection.
The subsea cable will be manufactured by Sumitomo Electric at its new factory at the Port of Nigg in Scotland. National Grid puts the investment in the factory at £350m; the facility is intended to become the UK's first domestic high-voltage direct-current subsea cable manufacturing plant.
The project adds another large HVDC programme to a growing UK subsea construction pipeline. LCM's October review of subsea energy infrastructure recorded major cable and converter-station packages across Eastern Green Link 3, Eastern Green Link 4 and other transmission schemes as network investment moves into longer construction programmes.
That workload extends beyond cable manufacture. Sea Link requires converter-station civils, underground cable corridors, landfall works, high-voltage equipment, network connections and commissioning across two onshore construction areas separated by the North Sea cable route.
Early site work has already started under separate permissions
Some investigation work began before the DCO decision. National Grid received separate local permissions in August for archaeological excavation and ground investigation near the proposed Kent converter station site, including work to identify unexploded ordnance and geoarchaeological conditions.
Those activities are separate from construction of the consented Sea Link scheme. Following the DCO decision, National Grid says it will now work with local authorities and other bodies to agree final technical details and discharge requirements covering matters including traffic and environmental management.
The project sits within a transmission network expansion that is increasingly shaping construction programmes beyond the energy sector itself. Earlier LCM analysis of grid constraints examined how limited electrical capacity and network reinforcement are affecting the timing of housing, logistics and data-centre development.
National Grid says Sea Link will increase transfer capacity between East Anglia and the South East and help bypass existing network bottlenecks around London. Government describes the connection as capable of carrying enough electricity for the equivalent of around two million homes.
Construction planning now moves into the final pre-start phase
National Grid will now review the detailed terms of the consent and continue construction planning, environmental commitments and engagement with landowners, councils and communities along the route. The developer has also proposed community funds of around £1.06m for Kent and £1.06m for Suffolk.
The National Grid programme currently puts the start of construction in early 2027 and completion in 2031. Before the main works begin, the project team will move through detailed construction planning and the discharge of requirements attached to the DCO.
Expert Verification & Authorship
Founder & Author, London Construction Magazine | Construction Testing & Investigation Specialist