National Grid says its Sea Link undersea cable is essential. We say the evidence doesn't support that and there are far cheaper options that do the same job with far less damage.

National Grid’s Latest Arguments for Sea Link Still Don’t Hold Up

National Grid has sent in more arguments claiming Sea Link is essential. Suffolk and Kent have examined them carefully and will show why they still do not hold up.

The project was originally justified as essential to export up to 2,000 MW of power from the Sizewell Generation Group in Suffolk. That claimed export shortfall is just 352 MW (and may not even materialise until the late 2030s). Yet National Grid is still pushing a giant £2.5 billion (and growing cost) for an undersea cable that is far too big for the real remaining problem.

1. National Grid’s “Need” Story Keeps Changing Originally, National Grid’s main report said the whole case for Sea Link rested on providing 2,000 MW of export capacity out of Suffolk. Now they are quietly downplaying that after we proved that was no longer required and are finding other areas instead. The new claims:

• Government reports (Clean Power 2030) prove Sea Link is “critical and urgent”

• Early construction funding proves it is needed

• Boundary problems in the network still require this exact project

2. Why the 2024 Clean Power 2030 Reports Do Not Prove Sea Link Is Critical or Urgent National Grid now says two 2024 government reports make Sea Link essential. Those reports do mention Sea Link, but they are wrong about why. They claim it is needed so two big offshore wind farms (Five Estuaries and Rampion 2) can connect to the grid.

The Government has since approved both wind farms without needing Sea Link at all. The official decision letters and reports for those projects say nothing about Sea Link being required. National Grid itself took part in both examinations and never argued that Sea Link was necessary.

Important point for the public: The same Government minister, Ed Miliband, personally signed the official decision letters approving both wind farms. He is also the Minister who will ultimately decide on Sea Link. His own decision letters say nothing about Sea Link being required. This completely undermines National Grid’s latest argument, the Government’s own later decisions show Sea Link is not critical for those projects.

3. Early Construction Funding Does Not Prove Need National Grid is now saying that because they received “early construction funding” from Ofgem, the project must be in the national interest.

Ofgem itself has stated clearly: “Approval of ECF does not constitute a full funding decision on the project. It is also not a relevant consideration or predeterminant of the DCO approval process.”

Using this funding as proof of need is simply circular reasoning. It does not help National Grid’s case at all. (Regulators approved early funding of £1.2 billion in November 2025 without considering these issues.)

4. The Claimed Sizewell Generation Group Export Shortfall Is Now Tiny The original claimed need to export 2,000 MW from Suffolk has collapsed to only 352 MW. This is mainly because one major project – Nautilus, a 1,400 MW electricity interconnector (an undersea cable linking the UK and Belgium) – was moved from Suffolk to the Isle of Grain in Kent in November 2024.

Even this small 352 MW export shortfall will not appear until the late 2030s at the earliest – and only if several other things all happen (including LionLink, a proposed 1,400 MW electricity interconnector between the UK and the Netherlands). LionLink is still unapproved, with its consultation only ending in March 2026, and it could be built somewhere else or not at all.

A 2,000 MW cable and three converter stations is completely out of proportion for a possible future 352 MW export problem. Even Nautilus landing in Kent at the Isle of Grain does not create a need for Sea Link – it is a separate project that can connect without it.

5. Network Boundary Problems (EC5, LE1 and SC2 in Kent) National Grid says Sea Link is also needed to fix problems at three network boundaries.

We have checked the numbers carefully:

• For EC5 and LE1 (in East Anglia), once you include all the already-planned upgrades (Norwich to Tilbury, Bramford to Twinstead, etc.) there is actually no shortfall left.

• The main Kent network problem (the “SC2 boundary”) is much bigger than Sea Link can fix. National Grid itself says there is a shortage of about 6,516 MW across the SC2 boundary in Kent under worst-case safety rules (N-1). Sea Link would only provide 2,000 MW of extra capacity. That leaves more than 4,500 MW of the problem still unsolved. If Sea Link were built, the Kent network would still not meet the official safety and reliability rules (NETS SQSS), therefore further work would still be needed.

A much cheaper and better option already exists right here in Kent: upgrade to a new 400 kV overhead line (OHL) between Canterbury North and Kemsley (about 29 km long).

• Cost: roughly £90 million (less than 10% of Sea Link’s cost).

• It would fully fix the entire 6,516 MW SC2 problem.

• It would also add extra resilience to the network and help electricity flow to where it is actually needed (the London area).

National Grid itself looked at this exact option (they called it “CAKE”) when they were planning other upgrades, so it is not a new or risky idea.

6. A Better, Cheaper and Less Damaging Alternative We have shown a simple, practical alternative that is:

• Much cheaper (roughly £170 million in Suffolk + £90 million in Kent – for example, upgrading the Sizewell to Bramford line, about 55 km, could cost under £200 million, compared to Sea Link’s £1.2–1.5 billion for just the Kent parts)

• Fully compliant with all safety rules

• Less damaging to the environment and communities

• Deliverable in the same or quicker timescale

The Suffolk part: Build a new 400 kV double-circuit overhead line between Sizewell and Bramford (55 km). The Kent part: Build a new 400 kV line between Canterbury North and Kemsley.

Together these two straightforward upgrades solve the remaining small export issue from Suffolk and the full Kent problem – without any giant undersea cable. They also link up neatly with other already-planned upgrades, creating a joined-up, efficient network.

Sea Link itself would still leave a large shortfall in Kent that would need yet more work later. Our alternative actually does the whole job properly.

proven Smarter and Cheaper Alternatives

Sea Link isn’t the most efficient or cost-effective choice. Better options include:

• Upgrading existing lines using advanced materials to “reconductor” current power lines (can double capacity quickly and cheaply; similar upgrades are already happening elsewhere).

• Non-construction fixes: Use software and services to balance power (like the Constraint Management Intertrip Service that can handle over 900 MW), add more battery storage (over 2.5 GW available), and adjust international cables to export instead of import (the UK often has extra power, but imports due to market prices create fake bottlenecks).

These alternatives are proven in the US and Europe, costing 50-75% less and taking months, not years. Newer 2025 forecasts from the National Energy System Operator (NESO) show that ongoing upgrades (like reconductoring lines between Tilbury and Grain) and these tools are enough. Demand in Kent and the southeast is growing but not as fast as predicted, and tech companies are now moving away from the grid and designing their own on-site generation. The latest NESO Summer Outlook (April 2026) actually highlights increasing periods of surplus generation rather than shortages.

clouding Rules and Transparency

There are conflicts and shortcuts in how this is being handled:

• Biases in Planning: National Grid groups control much of the process, potentially inflating the need to benefit their other projects like LionLink (the proposed UK-Netherlands interconnector).

• Ignoring Changes: Key updates, like Nautilus moving, haven’t led to revisions. Hearings in January 2026 exposed errors such as mispublished documents.

• Risky Funding: As noted earlier, early funding was approved without considering these issues.

Costs to You The £2.5 billion project would raise energy bills by about £108 per year, with little real benefit compared to the cheaper options. (Recent analysis suggests the true cost could now exceed £3 billion.)

Not justified

• The original claimed need to export large amounts of power from Suffolk no longer exists in anything like the scale that was promised.

• National Grid’s new arguments based on government reports and funding do not stand up.

• The network boundary problems can be fixed far more cheaply and with far less damage using proven overhead line technology.

• Sea Link is oversized, overpriced, and not the most efficient or economical solution required by national policy.

• National Grid signed major supply contracts in December 2025 while the independent DCO examination was still ongoing — this prejudges the outcome and the final decision still rests with the Secretary of State.