Britain approves Sea Link cable between Suffolk and Kent

Overview

Updated 1 hour ago

National Grid won development consent on 30 October for Sea Link, a 2-gigawatt electricity cable running about 138 kilometres between Suffolk and Kent. The application was filed in March 2025, examined over six months, and the project is not expected to be finished before 2031.

The link does not generate power. It moves it. Britain's network is split into sections that cannot always share electricity, and when a region holds more wind power than its wires can carry, the grid operator pays generators to switch off. Sea Link adds 2 gigawatts of transfer capacity across one of those seams.

Why it matters

Sea Link adds a 2-gigawatt seam between two grid regions, one of the bottlenecks that forces Britain to pay generators to switch off.

Questions about this story

Free account needed to ask — your question is kept and asked for you right after sign-up. Answers are public.

No questions yet — be the first to ask.

Key Indicators

2 GW

Transfer capacity

The link can move up to 2 gigawatts between the two regions, enough for the equivalent demand of about 2 million homes.

138 km

Route length

Most of the route runs offshore, with about 122 kilometres of subsea cable.

2M homes

Equivalent homes supplied

The government's comparison for carrying capacity, not a promise of new generation.

£3.2bn

Ofgem cost estimate

Up from original projections of £1.1 billion as the project's capacity increased.

£1.06M

Community fund per county

National Grid funding for Kent and Suffolk; the decision letter says the fund sits outside the consent order.

2031

Target completion

National Grid expects construction to begin in early 2027, subject to detailed construction planning.

Voices

Curated perspectives — historical figures and your fellow readers.

People Involved

Michael Shanks

Minister at the Department for Energy Security and Net Zero

Announced the consent decision

Baroness Curran

Signed the consent decision on behalf of the energy secretary

Acted under delegated authority

Sir Roger Gale

Conservative MP for Herne Bay and Sandwich

Opposes the project on cost grounds

Organizations Involved

National Grid Electricity Transmission (NGET)

Transmission network owner and developer

Holds consent; preparing for construction

The company that owns and operates the high-voltage transmission network in England and Wales and applied for Sea Link's consent.

Planning Inspectorate

Examining body for national infrastructure

Examined the application and recommended approval

The agency that runs examinations for major infrastructure projects and recommends decisions to ministers.

Department for Energy Security and Net Zero

Government department

Granted consent

The department that decides development consent for major energy projects and sets energy policy.

Ofgem

Energy regulator

Assessing the project's funding allowance

The regulator that sets how much transmission owners can recover from bill payers for network investment.

Sumitomo Electric Industries

Cable manufacturer

Named to supply the subsea cable

The Japanese manufacturer contracted to build Sea Link's subsea cable at its new Scottish factory.

The Great Grid Upgrade

Transmission programme

Programme of which Sea Link is a part

National Grid's programme of major transmission projects intended to connect new generation and reinforce the network.

Timeline

March 2025 October 2026

5 events Latest: Today

Tap a bar to jump to that date

October 2026
Government grants Sea Link consent
Today Decision

The energy secretary approves the project with modifications, including limits on landfall drilling methods.
Today
September 2026
Ofgem closes funding consultation
Regulatory

The regulator ends a separate consultation on the project's regulated revenue and outputs.
September 2026
July 2026
Examiners send recommendation to minister
Procedure

The Examining Authority finishes its report and passes it to the energy secretary.
July 30th, 2026
April 2025
Application accepted for examination
Procedure

The inspectorate accepts the application, opening a six-month public examination.
April 23rd, 2025
March 2025
National Grid files Sea Link application
Filing

The transmission owner submits its development consent application to the Planning Inspectorate.
March 27th, 2025

Scenarios

Construction starts on Sea Link in 2027

Likely Resolves by Q2 2027

Discussed by: National Grid, which says construction could begin in early 2027 subject to detailed planning

National Grid reviews the consent's requirements, locks in delivery partners and issues construction notices. Work begins at the converter station sites and along the onshore cable route, with subsea laying following later. The trigger is the company's own construction notice; the delay risk sits in the consent's detailed requirements, including the restriction to horizontal directional drilling or Direct Pipe at the landfall.

High Court challenge delays Sea Link

Possible Resolves by Dec 11, 2026

Discussed by: Planning-law commentators, who flag the statutory challenge window that follows a consent

A landowner, council or campaign group files a claim in the Planning Court arguing the decision was unlawful. A challenge does not automatically stop the project but can freeze parts of the programme while it is heard. The six-week window after the decision is the point of maximum risk.

Ofgem approves a Sea Link allowance above £3.2 billion

Possible Resolves by End of 2027

Discussed by: Energy Voice, reporting Ofgem's rising estimate; opponents including Roger Gale MP

The regulator finalises how much of the project's cost National Grid can recover from bill payers. If the allowance lands above the current estimate, the cost argument that surrounded the consent decision returns to the fore. The decision turns on Ofgem's assessment of scope and outputs, not on the planning merits.

Sea Link carries power by the end of 2031

Possible Resolves by End of 2031

Discussed by: National Grid, which gives 2031 as the expected completion date

The cable is laid, the converter station and substation connections are commissioned, and the link enters operation. Delivery of this kind of infrastructure routinely slips, and the project has already seen its cost estimate rise sharply. Completion would show the consent process converting into physical capacity.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

November 2008

Planning Act 2008 creates the development consent regime

Parliament passed legislation setting up a single consent route for nationally significant infrastructure, replacing a patchwork of separate approvals. It created fixed examination timetables and a body that became the Planning Inspectorate, with ministers taking the final decision on energy projects.

Then

Major energy projects began moving through a single examination instead of multiple consent regimes.

Now

The regime has decided 186 energy applications to date, including Sea Link as the 118th.

Why this matters now

Sea Link's six-month examination and ministerial decision follow exactly this template, which is why the process has a predictable timetable.

September 2014

Thames Tideway Tunnel consented (2014)

The 25-kilometre London sewer tunnel received its development consent after a lengthy examination, with an estimated cost of about £4.2 billion. Construction ran for roughly nine years before the tunnel became fully operational in 2025.

Then

Consent settled the route and construction methods but left years of works and cost scrutiny ahead.

Now

The project became a benchmark for how long a consented megaproject takes to deliver and how far costs can move.

Why this matters now

Sea Link follows the same sequence: consent now, construction from 2027, operation targeted for 2031.

1986-1994

Channel Tunnel built (1986-1994)

Britain and France agreed to build a fixed rail link under the English Channel, financed privately. Construction took eight years and the final cost was roughly double the original estimate.

Then

The tunnel opened in 1994 after repeated financing crises and delays.

Now

It became a standard reference for cost escalation on cross-border undersea infrastructure.

Why this matters now

Sea Link's estimate has already risen from £1.1 billion to almost £3.2 billion before a metre of cable is laid, a familiar pattern for undersea links.