Here you’ll find answers to some of the most frequently asked questions about Sea Link.
We hope they answer your questions and we will continue to update them as our work progresses. If your question is not listed below, get in touch with the team using the details provided on the Contact us page.
About Sea Link
Sea Link is a proposed electricity transmission network reinforcement between Suffolk and Kent, via a new, primarily offshore 2 gigawatt (GW) high voltage direct current (HVDC) link.
To bring the power from the subsea cables into and out of the electricity network in both Suffolk and Kent, we would need to build new onshore infrastructure including converter stations, substations and new underground and overhead electricity lines, as well as upgrading existing overhead electricity lines.
Power will be able to flow along the Sea Link cables in either direction, depending on where renewable energy is being generated at that time and where in the country power is needed.
Sea Link has been designed to increase the capability of the network to carry low-carbon and renewable energy from where it is generated to homes and businesses across the country.
Sea Link forms part of The Great Grid Upgrade, which will help with the transition to more secure, cheaper and cleaner forms of energy, helping to meet the UK’s net zero target.
We developed much of the existing network in East Anglia and Kent in the 1960s and it does not have sufficient capacity to carry future renewable and low-carbon power that’s forecasted to connect to the network – from offshore wind, interconnectors and nuclear power.
The four main reasons for reinforcement include:
the existing transmission network was not designed to transport electricity from where we increasingly now generate it (largely offshore)
the growth in offshore wind, interconnectors and nuclear power means that more electricity will be generated in the years ahead than the current network is able to securely and reliably transport
as a country, electricity demand is forecasted to at least double by 2050, increasing the amount of energy we need to transport to homes and businesses
upgrading the existing network as it is today (such as through replacing cables to carry more power) will not be enough to meet future demand whilst operating to required standards. This means we need to deliver new infrastructure whilst we upgrade the existing network.
The entire network is undergoing a transformation to ensure the grid keeps pace with this change and upgrades must be delivered for the UK to have a secure and stable transmission system which meets operating standards.
NGET alone is investing around £1.3 bn each year to adapt and develop our transmission network to connect new sources of low-carbon and green energy to our homes and businesses.
Sea Link is just one of several electricity network reinforcements that are needed to ensure the electricity transmission network is fit for the future and simultaneously deals with network constraints in both East Anglia and the south-east and was selected as the preferred solution to the shortfalls across both regions.
In Suffolk, our proposals for Sea Link include:
a connection from the existing transmission network via the proposed Friston substation, including the National Grid part of the substation itself
approximately 1.9 kilometres (km) of high voltage alternating current (HVAC) underground cable between the proposed Friston substation and a proposed converter station
a 2 GW high voltage direct current (HVDC) converter station near Saxmundham
approximately 10 km of HVDC underground cable between the proposed converter station near Saxmundham and a transition joint bay approximately 900 metres inshore from landfall, where the cable transitions between onshore and offshore technology
a landfall on the Suffolk coast, between Aldeburgh and Thorpeness.
You can read more information about our proposals in our Project update document.
Our marine proposals for Sea Link include:
approximately 122 kilometres (km) of subsea high voltage direct current (HVDC) cable between the Suffolk landfall location and the Kent landfall location.
You can read more information about our proposals in our Project update document.
In Kent, our proposals for Sea Link include:
a landfall point on the Kent coast at Pegwell Bay
a transition joint bay approximately 800 metres inshore, where the cable transitions between offshore and onshore technology, and approximately 2 km of high voltage direct current (HVDC) underground cable to a proposed converter station near Minster
a 2 GW HVDC converter station and substation near Minster
removal of up to 2.2 km of existing high voltage alternating current (HVAC) overhead line, and installation of approximately 3.5 km of new HVAC overhead line between the new converter station and substation near Minster and the existing Richborough to Canterbury overhead line.
You can read more information about our proposals in our Project update document.
Consultation activities so far
Between 24 October and 18 December 2022, we held an initial non-statutory consultation to introduce our proposals for Sea Link. This was an opportunity to explain why the reinforcement is needed, set out the options we have considered, and receive your early feedback.
We then refined our proposals based on feedback we received, input from specialists, environmental and engineering surveys, and design development.
Between 24 October and 18 December 2023, we held a statutory consultation on our refined proposals for Sea Link. As part of our application for development consent, we will prepare a Consultation report. This report will set out all feedback we received throughout each of our pre-application consultations, along with how we have had regard to that feedback.
Ongoing work
Since the close of our statutory consultation, we have made a small number of refinements to our plans for Sea Link, identified through feedback received and progression of ongoing design, technical and environmental work.
Until we submit our application for development consent, we continue to refine our proposals based on the feedback we receive from local communities, results from ongoing environmental assessments, surveys taking place along the route, and engagement with local authorities and stakeholders such as the Environment Agency.
Application for development consent
Once the consultation process and outstanding design, technical and environmental work is complete, we will submit an application for development consent to the Planning Inspectorate. If this application is consented, this will allow us permission to build and operate Sea Link.
We anticipate this application will be submitted in early 2025, though this date is subject to change.
We have made the following refinements to our proposals:
in Suffolk, the changes include an alteration to the cable route north of Aldeburgh, confirmation of the proposed access route to the converter station and changes to this access route and the associated bridge over the River Fromus. We are also proposing various changes to construction and maintenance access routes, compounds, and temporary overhead line diversion, and have identified additional land for environmental mitigation and enhancement. The strategy for coordination with other projects has also evolved
offshore, the changes include refinements to the cable route, additional marine areas for construction vessel maneuvering, and changes to the approach for backfilling marine trenches
in Kent, the changes include an increase of the overall maximum height of the converter station, confirmation of the type of pylon we intend to use for the connection to the existing overhead line and identifying a further construction and maintenance access route off Sandwich Road via the former hoverport. We are also proposing various other changes to construction and maintenance access routes, compounds, and temporary overhead line diversions, and have identified additional land for environmental mitigation and enhancement.
For detailed information on the full list of changes, please see our Project update document.
In Suffolk
Our proposals in Suffolk remain broadly the same as they were at our statutory consultation in 2023. We are still proposing to use underground cables between the proposed Friston substation, the converter station near Saxmundham and the landfall point on the Suffolk Coast. The route of these cables is mostly unchanged, and for the most part they will be constructed using standard open trenches. However, where our proposals interact with the Suffolk and Essex Coasts and Heaths National Landscape, we are proposing to use a trenchless construction method to install cables beneath the surface, therefore minimising disturbance to the natural environment.
Our proposals continue to allow for the co-location of key infrastructure with up to two future National Grid Ventures’ projects. Although it already has consent as part of another third-party project, we have kept the National Grid element of Friston substation within our proposals, to give us a comprehensive consenting position. If the substation is built under the existing consent, only a connection into it would need to be built as part of Sea Link.
At our statutory consultation in 2023, we sought views on potential converter station architectural design approaches. We are still in the process of considering feedback on this topic.
In Kent
Our proposals in Kent remain broadly the same as they were at our statutory consultation in 2023. We are still proposing to use underground cables between the landfall and proposed converter station, before using pylons to connect onto the existing Richborough to Canterbury 400 kV overhead line. The route of the underground cables and overhead line from the landfall point at Pegwell Bay, across to the proposed converter station and substation near Minster, and onto the existing overhead line, remains largely the same as it was previously. The route of these cables is mostly unchanged, and for the most part they will be constructed using standard open trenches. However, around the landfall point at Pegwell Bay we would use a trenchless construction method to install cables beneath the surface, therefore minimising disturbance to the natural environment.
The location of the proposed converter station and substation near Minster also remains the same as at our statutory consultation.
At our statutory consultation in 2023, we sought views on potential converter station/substation architectural design approaches. We are still in the process of considering feedback on this topic.
We are currently in the process of updating stakeholders on the changes we are making to our plans for Sea Link. We intend to make an application for development consent in early 2025, though this date is subject to change
The start of construction depends on the approval of our application for development consent. We currently anticipate the submission of our application to take place in early 2025, meaning that construction could commence in late 2026 or 2027, with the planning process typically taking place between 12-18 months.
We anticipate construction will be complete around 2030. This is to ensure the link is in place and connected to the rest of the network by the end of 2030. Some reinstatement and landscaping works would continue into 2031.
Local communities and the environment
We're dedicated to creating a positive impact in communities through infrastructure projects, emphasising social responsibility and equity via our Community Benefit Plan.
The Community Benefit Plan is split into four distinct pillars, each comprising several initiatives and schemes. These pillars are:
Grid for Nature - Develop green space for local and deprived communities to use and enjoy. Consists of the Woodland Strategy & Great British Bee Project initiatives, several regional/national partnerships, and green leases.
Net Zero Heroes - Form strong local partnerships with stakeholders close to our projects and through our in-house expertise, to help them realise their own climate ambitions.
Skills/STEM - Seek regional partnerships with suppliers to part fund the establishment of training centres and flexible training programmes to help give the next generation the skills they need to be part of the Net Zero Energy Workforce. Additionally, we will engage with schools and colleges through site visits, grants, and innovative targeted programmes that are aligned to the curriculum.
Community Benefit - Funds community projects that provide social, economic, and environmental benefits to local communities, ensuring we leave behind a positive legacy.
NGET's Community Benefit Plan aligns with National Grid’s Responsible Business Charter, emphasising impact in environment, communities, people, economy, and governance, shaping our strategic priorities with a focus on responsibility.
Our proposals in Suffolk have been developed for Sea Link as a standalone project, but also include opportunities to co-locate infrastructure for up to two further projects at the converter station, along the cable corridors and at the landfall location. We are also committed to exploring how we can coordinate our construction activity with other developers, like Scottish Power Renewables and EDF. We are also considering and assessing the potential for cumulative impacts arising from other projects as part of our ongoing Environmental Impact Assessment and we are seeking your views on our approach.
National Grid is committed to being a good neighbour and we fund projects run by charities and community groups that meet local community needs by providing a range of social, economic and environmental benefits.
There are several key differences between these projects that restrict the ability of all applications to be brought forward as on single DCO.
Sea Link is part of The Great Grid Upgrade and is an essential network reinforcement and standalone project
The projects are being promoted by different companies, with different project teams covering several different geographical locations who are at different stages. Making coordination into a singular DCO or examination unworkable given the need to deliver Sea Link by 2030
The businesses are separate legal entities and have different statutory duties
We work closely with local communities to make sure we minimise construction impacts as much as we can and support community initiatives in areas where we are working to deliver social, economic or environmental benefits. During construction we will need to do a range of temporary activities such as creating equipment storage areas, site offices, and road and public rights of way diversions will need to be implemented. Before we do this, we will prepare a construction management plan that will set out controls and measures to reduce our impact on the local community. We might still need permanent access rights for maintenance.
As the UK looks to accelerate its economic recovery following the coronavirus pandemic, strategic infrastructure solutions such as those proposed along the east coast can help ensure that the UK continues to deliver strong, sustainable growth.
The Sea Link Reinforcement Project is one of the essential network reinforcements needed to deliver on the UK’s net zero target – without it, low carbon, renewable energy generated offshore would not be able to be transported to homes and businesses across the country.Sea Link would help connect renewable sources of energy to homes and businesses helping to deliver 50 GW of offshore wind by 2030 and ultimately net zero.
EMFs are electric and magnetic fields. Electric fields are produced by voltage and magnetic fields by current flowing through a conductor. Overhead lines are a source of two fields: the electric field (produced by the voltage) and the magnetic field (produced by the current). Underground cables eliminate the electric field altogether as it is screened out by the sheath around the cable, but they still produce magnetic fields.
Background EMFs are present in most homes. They come from the house wiring, electrical appliances and the low-voltage distribution cables that carry electricity along streets.
Some people worry that Electromagnetic fields (EMFs) may have negative health effects. We take these concerns seriously and want to keep the public, our contractors and employees safe. We ensure all of our existing and proposed equipment, including those on this project, comply with independent safety guidelines set to protect us all against EMF exposure. After decades of research the weight of evidence is against there being any health risks of EMFs below the guideline limits.
For further information on EMFs visit our website, www.emfs.info. If you would prefer to talk about your concerns, please do not hesitate to call the EMF helpline on 0845 702 3270 or email [email protected].
We are rigorously assessing Sea Link's impact on designated sites and the environment, adhering to the "mitigation hierarchy" by avoiding, minimising, restoring, and offsetting impacts. Our efforts include micro-siting cables, using non-intrusive methods, and ensuring a 10% Biodiversity Net Gain, which means that the local environment will be left in a demonstrably and measurably more biodiverse state than prior to the commencement of the Project. This will be achieved by a range of measures, such as habitat creation and enhancement for protected species.
We'll conduct a comprehensive environmental impact assessment, meeting legal requirements under the EIA Regulations. Stakeholders can comment on our Preliminary Environmental Information Report (PEIR), and when we submit our application for development consent, we will include the full Environmental Statement accounting for expert and public feedback received during consultation.
All construction schemes have a target of delivering 10% Environmental Net Gain (which must include a minimum of 10% Biodiversity Net Gain).
Green Infrastructure (GI) features can contribute to a project's BNG calculations and there are a range of GI features that can be included, such as:
green roofs, green walls and Sustainable Drainage Systems (SuDS);
landscaping included within the Post-Development Plans.
It is possible to use sites delivering nutrient neutrality/ a suitable alternative natural greenspace (SANG)/Great Crested Newt habitat to also deliver net gain, on the basis that:
delivery of the non-BNG outcomes can contribute to a point equivalent to no net loss of BNG but NOT beyond
additional habitat features created or enhanced on the same land beyond those delivered for non-BNG outcomes (i.e.in addition) could take you into positive BNG territory.
Onsite: Within the project’s development area
Offsite:
land owned by the client
land leased by the client
Offsite: Use a financial contribution to offset impacts
through discussions / agreements with the Local Planning Authority /Local Wildlife Trust
through a Habitat Banking / Biodiversity Unit Provider
through the use of Government Statutory Units (last resort)
National Grid’s non-operational land can be used for offsite mitigation.
The ‘offsite’ locations could be either a wildlife site or nature reserve and would meet the ‘ecologically desirable’ criteria. National Grid will implement a range of strategies to protect and improve known wildlife sites and nature reserves as well as creating new habitats where appropriate.
Infrastructure and construction methods
A converter station houses the technology that converts electricity between alternating current (AC) and direct current (DC) and enables it to be transmitted over long distances. AC current is used in each country’s transmission system to power homes and businesses, while DC is used for sending electricity more efficiently over long distances.
Substations house electrical equipment which enables the system operator to control the flow of electricity. These substations come in many sizes and configurations depending on the need. Substations are also key in helping to isolate and fix faults and allow maintenance to be undertaken safely on the electricity network.
Cable joint bays are needed at intervals of approximately 500 metres to 1,000 metres when constructing underground cables, to allow for individual sections of cable to be joined together. In areas where a cable joint bay is needed, a wider cable corridor may be required.
Cable ducts are sections of tubing where electricity cables are placed.
A link box is an above ground kiosk which allows inspection and maintenance of the cables.
Transition joint bays are used to connect an onshore cable to an offshore cable. These are generally around 10 to 15 metres in length, 5 metres in width (dependent on design requirements) and are located near the coast.
We are proposing to use a range of construction methods for Sea Link. These include underground cable installation, which requires an area beyond the corridor, accommodating site compounds and material storage. Trenchless crossing which minimises surface interaction, reducing impact on wildlife and communities. Subsea cable installation, which involves precise surveys and specialised cable-laying vessels.
We are proposing to use a range of construction methods for Sea Link. These include underground cable installation, which requires an area beyond the corridor, accommodating site compounds and material storage. Trenchless crossing which minimises surface interaction, reducing impact on wildlife and communities. Subsea cable installation, which involves precise surveys and specialised cable-laying vessels.
Overhead electricity transmission lines typically involve building new steel lattice pylons to support the wires (conductors). The size, height, and spacing of pylons are determined by safety, topographical, operational, and environmental considerations. A typical 400 kV pylon is around 50 metres tall.
Draft order limits form the current anticipated boundary of the entire area within which Sea Link could take place.
Limits of Deviation lie within the Draft Order Limits, they give us flexibility when constructing the project in case of unforeseen circumstances (such as unexpected environmental constraints), they allow us to move infrastructure within the Draft Order Limits. We would not need all of the land within the draft order limits, but permanent infrastructure could be installed within the Limits of Deviation.
Yes. Potential effects on tourism are being assessed as part of our Preliminary Environmental Impact Report. Measures have been considered throughout the construction phase of the project that would look to manage the impacts that could impact tourism such as footpath or road closures impacting journey times and travel patterns.
What will you be doing to mitigate the impact of HGVs on the local road network during construction?
Within our outline code of construction practice, we are considering a range of measure that would help control the management of impacts on local traffic and transport. Our traffic management plan will set out how we plan to reduce route and journey mileage to and ensure considerate parking practices in local areas. We will work closely with the local authority and take guidance from them to further reduce our impact such keeping our movements to earlier in the day.
Proposed working hours will be included within the environmental impact assessment. The exact timings will form a requirement of the Development consent order. We will do as much as we can to keep disturbance to the local community to a minimum.
We don’t anticipate closing any public footpaths permanently, but we will need to redirect public rights of way during the construction phase and possibly permanently Our traffic management plan will set full details of where and when these will be implemented. We will keep the community informed at all times and provide as much notice as possible.
The power needed is still required to come onshore and feed into the network at the right places, otherwise we wouldn’t be adding to capacity and resilience where it is needed. Even predominantly offshore projects need to come onshore and link into the network in order to take power from where it is generated to where it is needed up and down the country.
To put this into perspective, successfully delivering the Government’s 50 GW of offshore wind ambition will require significant new onshore and new offshore electricity transmission network being consented and delivered within this decade across the east side of the country.
What's energy resilience got to do with movie marathons? Find out how – and why – we’re connecting more clean energy to power the things you love.
Find out more