Sea Link

National Grid signed a contract arrangement with Siemens Energy to build the Sea Link HVDC converter stations in Suffolk and Kent. The December announcement followed Siemens Energy’s earlier designation as preferred bidder and moved the converter-station scope from procurement stage toward formal delivery planning, while noting the project remained subject to planning consent and a construction start was expected in 2027 if approved.

On 26 November 2025 the applicant submitted a formal change request to amend elements of the previously submitted DCO (change application). The Examining Authority accepted the change application into the examination process and published associated documents and hearing arrangements (ExA hearings and registration deadlines followed in Dec 2025 and Jan 2026).

National Grid carried out ground investigation works at the Kent converter station site (west of the A256) in October–November 2025. The programme comprised temporary boreholes and trial pits to collect subsurface data to inform detailed design and foundation selection; activities were subject to landowner access and statutory approvals.

National Grid awarded positions under its HVDC converter and onshore cable civils supply-chain frameworks to multiple major civils contractors (including Balfour Beatty, BAM Nuttall, Galliford Try, Laing O’Rourke, Skanska, Taylor Woodrow, Murphy and VolkerFitzpatrick). The framework covers confirmed and anticipated HVDC projects, explicitly referencing Sea Link among projects that may draw on these framework suppliers for converter-station civils and onshore cable civils work.

National Grid selected Siemens Energy as the supplier of HVDC converter stations for the Sea Link project as part of its GBP 12 billion HVDC supply chain framework awards announced on 21 August 2025. The converter stations will be located in Suffolk and Kent, converting AC power to DC for transmission through the 138 km subsea cable and back to AC at the receiving end.

National Grid named Sumitomo Electric Industries as preferred bidder to supply and install the 138–140 km, 525 kV HVDC subsea cable for Sea Link, a 2 GW connection between Kent and Suffolk. The announcement confirmed cable manufacturing would be carried out at Sumitomo’s new Port of Nigg facility in Scotland (a ~£350m investment) and that Sumitomo would work with National Grid to finalise contract terms; Sea Link remained in planning consent process at the time.

National Grid named Siemens Energy as preferred bidder to deliver the two HVDC converter stations for the 2 GW Sea Link project, with one converter station proposed in Suffolk and one in Kent. The preferred-bidder decision followed an extensive competitive procurement process and enabled National Grid and Siemens Energy to begin planning activity ahead of full contract award; the announcement noted Sea Link remains subject to planning consent and, if approved, construction is expected to start in 2027.

National Grid submitted the Environmental Impact Assessment material for Sea Link as part of its Development Consent Order (DCO) application in March 2025. The submission bundled the Environmental Statement / supporting environmental information (building on earlier PEIR material) covering topics such as ecology, landscape & visual, water environment, noise, traffic, cultural heritage and mitigation measures, and formed the formal EIA package for statutory examination by the Planning Inspectorate.

The wintering bird survey campaign for Sea Link concluded in March 2025, providing count data and observational records used in the Environmental Statement and to inform mitigation and route selection decisions.

On 28 March 2025 National Grid submitted an application for development consent for the Sea Link project to the Planning Inspectorate. The submission requested permission to build the proposed HVDC subsea connection (approximately 130–138 km) between Pegwell Bay in Kent and the Suffolk coast, together with associated onshore infrastructure including converter stations, substations and new underground/overhead lines. National Grid stated the filing followed multiple rounds of public consultation and initiates the Nationally Significant Infrastructure Project (NSIP) examination process during which the Examining Authority will review the proposals and hear representations from stakeholders.

National Grid began wintering bird surveys in December 2024 across Suffolk (Friston, Sternfield, Church Common, Aldeburgh) and adjacent buffers to establish baseline winter bird presence and abundance for the Environmental Statement and route design assessments; surveys included monthly field counts and foreshore counts where relevant.

National Grid (NGET) commissioned NextGeosolutions to survey five additional Sea Link route areas; fieldwork was executed using the vessels SHORE Possibility (shallow/Area 1) and SHORE Presence (nearshore). The campaign acquired MBES, SSS, sub‑bottom profiling, sparker and magnetometry to characterise seabed morphology, shallow sediments and potential habitats; an interpretation report was published 20 Dec 2024.

Archaeological surveys associated with the Sea Link onshore route commenced in July 2024. The programme included trial trenches and targeted excavations to identify archaeological features along the proposed cable corridor; work continued into 2025 to inform siting and consenting.

A comprehensive geophysical survey of the Sea Link main offshore route was completed by MMT in 2022. The campaign provided baseline MBES, SSS and sub-bottom data used to map bathymetry, seabed features, sandwaves and potential sensitive habitats and underpinned subsequent route planning and additional targeted survey work.