About Sea Link | National Grid ET

National Grid is proposing to reinforce the electricity network across Suffolk and Kent.

Sea Link is a proposed new 2 gigawatt (GW) subsea high voltage direct current (HVDC) electricity connection, approximately 140 km in length and predominately offshore. This includes HVDC converter stations and high voltage alternating current (HVAC) connections onto the national electricity transmission system.

The UK Government has indicated its ambition to achieve net zero emissions by 2050. This means achieving a balance between the greenhouse gases put into the atmosphere and those taken out. The energy industry plays a key part in this transition, from developing the use of renewable energy generation, to upgrading the existing transmission network to allow communities across the country to benefit from this clean energy.

By building Sea Link, we will increase the network’s capacity to manage new energy transmission in and out of Kent and Suffolk to meet local and national energy demands.

Our proposals

The majority of Sea Link will be offshore HVDC subsea cables, with onshore infrastructure at either end connecting it to the transmission network. The exact route of the line will be informed by onshore and marine surveys plus feedback from our non-statutory consultation, which took place between October and December 2022.

We will use the feedback received from our non-statutory consultation, and the results of further technical assessments and surveys to refine our proposals. We will present and seek feedback on our updated proposals during our statutory consultation in 2023.

Power is generated and consumed in all regions of the UK, however, some regions generate more or consume less than others, and surplus electricity is shared across the country. In addition, surplus power is traded with our European neighbours through electricity interconnectors. Reliance on interconnectors will increase as a means of balancing the peaks and troughs in our domestic electricity generation, as a growing amount will be intermittent due to it being increasingly weather dependent. For example when wind generation is high, surplus power will be exported, and when wind generation is low, some of our needs will have to be met by importing power.

To learn more about our proposals that we consulted on during our non-statutory consultation, you can watch a recorded presentation by the project team on each of the three topics:

Our proposals in Suffolk

Marine route proposals

Our proposals in Kent

Sea Link includes:

Two HVDC converter stations, one in Kent and one in Suffolk
Approximately 140 km of underground and subsea electricity cables between these two stations
An underground cable connection to the proposed Friston substation in Suffolk
An underground cable or overhead line connection to the existing Richborough to Canterbury overhead line in Kent

In our proposals, you will find route corridors that are shown as a ‘graduated swathe’. We are considering siting new infrastructure somewhere within the graduated swathe, but darker areas show our preferred locations based on the assessments we have completed so far.

To explore the proposals we presented at our non-statutory consultation (October to December 2022), please use the drop-down buttons and links below. You can find more about the need for Sea Link, and our approach to routing and siting, in the project background document and other key materials within the document library.

Suffolk

Our study area is between the river Alde in the south, Minsmere in the north and the A12 in the west.

Our emerging preferences

On balance, a landfall between Aldeburgh and Thorpeness has been identified as the emerging preference for Sea Link. This is because it minimises interaction with other infrastructure in the immediate nearshore environment and avoids a nearshore geological feature, the Coralline Crag. The appraisal also identified that this landfall presents opportunities for coordination with other proposed developments.

Two converter station sites have been identified as emerging preferences, Site 1 which is located to the south of Knodishall and Site 3 which is located to the east of Saxmundham.

Both sites have existing woodland screening and present further opportunities to incorporate further mitigation planting into the design of the site. Both sites also minimise the length of the overall onshore cable corridors from the landfall and provide opportunity for a high voltage alternating current (HVAC) connection into the proposed Friston substation.

An alternative landfall, in the proximity of Sizewell nuclear power station, and onward terrestrial cable corridors to Sites 1 and 3 has also been identified. Based on the work we have done to date, we believe that landfall in the proximity of Sizewell can only accommodate one set of cables, thereby reducing the opportunity for coordination.

Two converter station sites have been identified as emerging preferences: Site 1 which is located to the south of Knodishall and Site 3 which is located to the east of Saxmundham.

For further information, please click here to read more about our proposals for Suffolk or watch a recorded presentation delivered by the project team.

Marine

Our study area runs from the Suffolk coast, in the vicinity of the existing network and the proposed Friston substation; to the Kent coast, in the vicinity of the existing network near to Richborough substation.

Our emerging preference and alternative option

A marine route corridor between a landfall on the Suffolk coast between Aldeburgh and Thorpeness and a landfall on the Kent coast at Pegwell Bay has been identified as the emerging preference. The marine route corridor emerging preference avoids or minimises interactions with marine designated sites, maintains sufficient water depth at crossings of other cables, whilst also minimising interactions with other marine users as far as possible.

An alternative marine route corridor landing in the proximity of Sizewell nuclear power station has also been identified for the Suffolk section of the marine route corridor.

For further information, please click read to read more about our marine proposals or watch a recorded presentation delivered by the project team.

Kent

Our study area is between Herne Bay on the north Kent coast and Sandwich Bay on the east Kent coast.

Our emerging preference

On balance, we have identified our preference as a route which runs from a landfall in Pegwell Bay to a proposed converter station site north east of the existing National Grid Richborough substation, and an HVAC connection back onto the existing overhead line to the south of Minster. This has sought to minimise the length of the onshore project whilst avoiding an area of challenging seabed on the north Kent coast.

To make it easier to understand our plans, we have broken the route of the project down into various sections, as set out in the links below.

Throughout our detailed proposals, you will find route corridors that include a ‘graduated swathe’. We are considering building the new link anywhere within the route corridors, but darker areas of the swathe show our preferred location for infrastructure, based on the assessments we have completed so far. We will use feedback from this consultation and further investigative work to confirm the precise route and will share details of this route at our statutory consultation in 2023.

For further information, please click read to read more about our proposals in Kent or watch a recorded presentation delivered by the project team.

Find out more about our proposals