Government approves Sea Link undersea power connection between Suffolk and Kent
The government has given National Grid permission to build a major electricity connection running beneath the sea between Suffolk and Kent. The Sea Link project will carry up to 2GW of power across 138 kilometres, mostly underwater. Consequently, it could move enough electricity to supply around two million homes.
Energy Secretary approval came through a Development Consent Order on 30 October 2026. The Planning Inspectorate examined National Grid's application before recommending consent. This decision marks the end of formal planning and opens the way for construction preparation.
For many businesses, this appears to be infrastructure happening elsewhere. However, the project reflects wider changes to how electricity moves around the country. Those changes have commercial consequences for energy costs, supply reliability, and the viability of renewable energy contracts.
Suffolk to Kent: where the cable will run
Sea Link will land on the Suffolk coast between Aldeburgh and Thorpeness. From there, it runs subsea to Pegwell Bay in Kent. Around 130 kilometres of the route will be underwater. The remaining sections will be underground cable, connecting to converter stations near Saxmundham in Suffolk and Minster in Kent.
The converter stations will switch electricity between direct current for the subsea cable and alternating current for the national grid. These stations will reach up to 26 metres in height. New substations and transmission connections will tie the cable into the existing high-voltage network at both ends.
National Grid refined its design after several rounds of consultation. Initially, the company considered a separate landfall at Sizewell. Following feedback from more than 1,000 residents and stakeholders during statutory consultation in late 2023, the plan shifted to a single Suffolk landfall and more underground cabling.
Why electricity needs to move from east to south
Offshore wind farms are being built across the North Sea and around East Anglia. Meanwhile, the largest centres of electricity demand sit further south and west. Without adequate transmission capacity, power generated in one region cannot reach consumers in another.
When generation exceeds what the local network can carry, renewable electricity gets curtailed. Operators pay wind farms to stop generating, and that cost ultimately flows through to consumer bills. Therefore, transmission projects such as Sea Link aim to reduce wasted renewable energy by moving it to where it is needed.
National Grid says the project will support offshore wind, interconnectors, and nuclear generation. It should also strengthen grid resilience by creating alternative routes for power to flow across the country. The government added that Sea Link will help deliver more secure, clean electricity to homes and businesses.
The connection does not generate electricity itself. Its value lies in moving power efficiently between regions. As wind capacity grows, the ability to shift electricity from areas of high generation to areas of high demand becomes increasingly important.
Construction timeline and UK manufacturing
National Grid expects construction to begin in early 2027, subject to detailed planning and contractor arrangements. The target completion date is 2031. That timeline depends on securing land, finalising environmental mitigation, and coordinating marine and onshore works.
Sumitomo Electric will manufacture the subsea cable at its new £350 million factory at the Port of Nigg in Scotland. This contract represents a significant piece of UK supply chain activity. It also means the project will support jobs and investment beyond the immediate construction corridor in Suffolk and Kent.
Physical works will include subsea cable installation, underground cable sections at both landfalls, converter stations, substations, and transmission connections. Additionally, there will be marine construction, environmental monitoring, and access works during the build phase.
What this means for energy costs and contracts
Transmission constraints raise the cost of running the electricity system. When the grid cannot move power from where it is generated to where it is needed, the system operator must intervene. These interventions include paying generators to reduce output in one location and paying other generators to increase output elsewhere. The costs appear in network charges and, ultimately, in business energy bills.
Sea Link should reduce these constraint costs by improving the flow of electricity between East Anglia and the South East. For businesses in Kent and the wider South East, that could mean more stable access to renewable electricity and less reliance on higher-cost generation during periods of high demand.
Companies with renewable energy contracts tied to specific generation sources may also benefit. If transmission bottlenecks prevent wind farms from exporting power, those contracts deliver less value. Better transmission infrastructure makes renewable generation more reliable and, therefore, more commercially viable.
Moreover, businesses tendering for public sector contracts increasingly face net-zero requirements. Access to renewable electricity is becoming a competitive factor. Projects such as Sea Link do not solve every challenge, but they improve the infrastructure that makes low-carbon energy accessible.
Energy security also matters. Additional transmission capacity within Great Britain reduces the risk of regional supply shortages. However, Sea Link will not eliminate exposure to volatile fuel prices or the intermittency of renewable generation. Its benefits depend on how it operates alongside other network upgrades and new generation projects.
Local impacts in Suffolk and Kent
Communities near the converter stations, substations, and cable routes will experience construction disruption. Temporary impacts include noise, traffic, and access restrictions. Permanent infrastructure will create visual and land-use effects, particularly around the converter stations and substations.
National Grid has committed to ongoing environmental mitigation and community engagement. The Development Consent Order includes conditions covering construction methods, environmental monitoring, and stakeholder communication. Detailed plans will be finalised as the project moves into delivery.
Offshore, the cable route requires marine construction and environmental assessment. Seasonal restrictions and monitoring requirements will be established to manage impacts on marine habitats and species. The final environmental footprint will depend on construction methods and mitigation measures implemented during the works.
Five key points about Sea Link
- The Development Consent Order approved on 30 October 2026 allows National Grid to build a 2GW subsea electricity connection between Suffolk and Kent.
- Construction is expected to begin in early 2027, with completion targeted for 2031, subject to detailed planning and contractor arrangements.
- The cable will run approximately 138 kilometres, with around 130 kilometres subsea and the remainder underground, connecting to converter stations near Saxmundham and Minster.
- Sumitomo Electric will manufacture the subsea cable at its £350 million facility at the Port of Nigg in Scotland, supporting UK supply chain activity.
- The project aims to reduce wasted renewable electricity by improving transmission capacity between areas of high generation and high demand, potentially lowering system constraint costs.
Preparing for delivery after planning consent
Approval of the Development Consent Order is a significant milestone. Nevertheless, it does not complete the project. National Grid must now review the conditions attached to the consent, finalise engineering and construction plans, and continue environmental assessment work.
Land acquisition and contractor arrangements will proceed in parallel. The company will also maintain engagement with communities and other stakeholders as construction approaches. These steps are essential to meet the early 2027 construction start date.
Businesses affected by the construction corridor should expect further communication from National Grid. Companies in Suffolk and Kent may face temporary access restrictions or changes to local infrastructure. Planning for these disruptions now will help minimise operational impacts later.
For businesses with energy-intensive operations, the broader context matters. Sea Link is one project within a wider programme of transmission upgrades across Great Britain. The cumulative effect of these projects will shape electricity costs, supply reliability, and the availability of renewable energy over the next decade.
Companies reviewing their energy strategies should consider how transmission improvements align with their own net-zero plans. Better grid infrastructure makes renewable energy more accessible. However, it does not guarantee lower costs or eliminate all supply risks. Businesses still need to manage their energy use, explore on-site generation, and understand their exposure to network charges.
At SBS, we support businesses through carbon reporting and PPN 06/21 compliance, helping you understand how infrastructure changes such as Sea Link affect your energy strategy. Our ESG compliance services provide practical support for businesses navigating regulatory requirements and tender expectations.
Transmission upgrades and the wider grid context
Sea Link forms part of a larger transformation of Britain's electricity system. Offshore wind capacity is expanding rapidly. Transport and heating are electrifying. Older coal and gas plants are retiring. Consequently, the grid must move more power over longer distances than it was originally designed to handle.
Other transmission projects are progressing alongside Sea Link. These include onshore reinforcements, new substations, and additional offshore connections. Together, they aim to create a more flexible and resilient network capable of integrating large volumes of renewable generation.
The pace of delivery matters. If transmission infrastructure lags behind new generation, constraint costs will rise. Wind farms will be paid to curtail output, and businesses will face higher network charges. Therefore, timely completion of projects such as Sea Link is essential to controlling energy system costs.
For businesses, this infrastructure shift creates both opportunities and risks. Companies that can access renewable electricity reliably will be better placed to meet net-zero commitments and compete for public sector contracts. However, those in areas with transmission constraints may face higher costs and less stable supply.
Understanding how transmission projects affect your region is increasingly important. Businesses in East Anglia may see more competition for grid connections as offshore wind capacity grows. Companies in the South East may benefit from improved access to renewable electricity as projects such as Sea Link come online.
Where to find more information
The Department for Energy Security and Net Zero oversees major energy infrastructure projects and publishes updates on policy and consent decisions. The Planning Inspectorate provides details of development consent applications, examination timetables, and decision documents for nationally significant infrastructure projects.
National Grid publishes project information, consultation responses, and construction updates on its website. The company also maintains community engagement channels for residents and businesses affected by its projects. For marine and environmental aspects, the Marine Management Organisation regulates offshore works and provides guidance on consenting and environmental compliance.
Businesses seeking to understand how transmission projects affect their energy costs and supply options should review their network charges, generation contracts, and regional grid constraints. Professional advice on energy strategy and carbon reporting can help you navigate these changes and align your operations with evolving infrastructure.