Eastern Green Link 1

Survey operations for Eastern Green Link 1 (EGL1) officially commenced in June 2025. Prysmian, the main EPCI contractor, commissioned Next Geosolutions to carry out comprehensive land topographic and marine geophysical surveys along the nearshore and offshore sections of the proposed 190 km subsea cable corridor between Torness (East Lothian) and Hawthorn Pit (County Durham). The campaign deployed advanced survey vessels and ROVs to collect multibeam echosounder (MBES), side-scan sonar (SSS) and sub-bottom profiling data to inform final route micro‑routing, cable burial requirements and risk mitigation ahead of cable installation. The programme was described as the critical data-gathering phase for detailed design and engineering and was scheduled across 2025.

On 9 April 2025 Ofgem published a consultation recording that the EGL1 joint venture had applied for an ASTI ODI Penalty Exemption Period after seeking a 480‑day exemption, citing global unavailability of equipment and supply‑chain capacity. The consultation noted the JV’s claim that these supply‑chain constraints had delayed delivery and recorded that the project’s current expected delivery date was April 2029 (around 16 months later than previously required). Ofgem published its provisional view and sought stakeholder responses on whether the delay qualified for exemption.

Onshore construction works for Eastern Green Link 1 commenced and the project entered the construction phase, with offshore construction scheduled to start in the summer. The announcement confirmed that awarded suppliers (including Prysmian and the GE Vernova–MYTILINEOS consortium) had moved from contract award and design into execution, supporting the project’s delivery timeline toward a targeted in‑service date.

Pre‑installation and environmental baseline surveys for EGL1 commenced during the project enabling phase in 2024 (and continued into 2025). These studies included seabed and intertidal ecological baseline surveys, geophysical mapping, archaeological assessment and land topographic surveys around the Torness and Seaham landfalls to inform environmental impact assessment, micro‑routing and onshore enabling works. The Environmental Appraisal Report (EAR) documented the required survey methods and their purpose in supporting micro‑routing and mitigation.

As part of pre‑installation activities, EGL1's Environmental Appraisal Report set out a UXO management strategy and the requirement for site‑specific unexploded ordnance (UXO) surveys from 2024 onwards. The approach included desk-based assessment followed by targeted UXO survey work in areas of moderate and high risk, identification and verification of potential UXO (pUXO) targets and, where necessary, seabed excavation using divers (<10 m) or ROVs (>10 m) and clearance (including controlled detonation under separate consents) prior to further works.

Ofgem issued its final Project Assessment decision for Eastern Green Link 1 on 14–15 November 2024, approving regulatory funding allowances under the ASTI framework. Ofgem set a total funding allowance of £2,001,104,429 (2018/19 prices) for delivery of EGL1, comprising £1,657,441,102 for direct construction costs and £343,663,327 for indirect costs and risk, and established a 1% COAE materiality threshold and new reopener arrangements. The decision provided the JV with an agreed regulatory funding envelope to progress construction and allowed routes for further funding of specific uncertain costs.

The Secretary of State confirmed, with modifications, the Compulsory Purchase Order (CPO) enabling National Grid Electricity Transmission to acquire the land and rights necessary to construct and operate the English onshore elements of the project. The CPO confirmation (1 August 2024) followed an inquiry and negotiations intended to secure necessary land interests to deliver the onshore converter/substation, cable corridors and associated works.

Eastern Green Link 1 (EGL1) was established as a joint venture between National Grid Electricity Transmission and SP Transmission (part of SP Energy Networks) to develop a 2 GW, 525 kV HVDC subsea transmission link between Torness (East Lothian) and Hawthorn Pit (County Durham). The partners committed to a joint £2.5 billion investment to enable large-scale transmission of renewable electricity along the east coast, with the JV coordinating design, procurement and delivery activities and awarding major equipment and cable contracts to suppliers. The JV existed publicly by December 2023 when project contracting progressed.

Eastern Green Link 1 Ltd awarded Prysmian Group the cable supply contract to deliver the project’s HVDC cable system, selecting the company to manufacture and supply the UK’s first 525 kV HVDC XLPE submarine cable for the ~190 km route (requiring nearly 400 km of cable). The award formed part of a package of major supply contracts announced for EGL1 and enabled the project to progress from procurement into the design phase and towards construction.

The GE Vernova – MYTILINEOS consortium was awarded the contract to supply and construct both HVDC converter stations for EGL1. GE Vernova supplied VSC HVDC technology (including VSC valves and the eLumina control system) from UK facilities while MYTILINEOS took responsibility for EPC civil works, balance of plant and installation. The award progressed the project from preferred supplier stage into detailed design and delivery planning.

The Eastern Green Link 1 joint venture (National Grid Electricity Transmission and SP Transmission) submitted its initial costs and funding request to Ofgem in September 2023 as part of the Accelerated Strategic Transmission Investment (ASTI) Project Assessment (PA). The submission set out direct construction costs and higher-confidence contingency requests (P50/P80) and sought regulatory funding allowances and reopener mechanisms to manage uncertainty and delivery risk. This application initiated Ofgem’s PA process for EGL1 and triggered subsequent consultations on cost allowances, contingencies and mechanisms for potential further funding.

The EGL1 joint venture selected a consortium led by GE Vernova’s Grid Solutions business, in partnership with MYTILINEOS Energy & Metals, as preferred suppliers to provide the two HVDC converter stations (one at each end of the link). The appointment covered engineering and technology for VSC HVDC terminals that will convert DC to AC for connection into the onshore transmission network; full contracts were contingent on final regulatory approvals from Ofgem.

A marine licence decision letter for the project was issued on 20 July 2023 (marine licence reference L/2023/00212/1), representing the licensing authority's determination on the marine permit for the subsea cable. The decision followed the 2022 marine licence application and associated Marine Environmental Reports submitted by the JV to enable the subsea installation and associated marine works.

East Lothian Council issued an in-principle planning permission for the Scottish onshore elements of EGL1 in May 2023, permitting the principle of the proposed onshore infrastructure (including the proposed Branxton substation site near Dunbar) subject to detailed design and statutory consents. This in-principle decision followed pre-application engagement and scoping of environmental matters for the Scottish onshore works.

The East Lothian Council in-principle planning decision in May 2023 for the project's Scottish onshore elements indicated acceptance of the environmental assessments submitted for that element of EGL1, including the EIA scoping and assessment materials used to inform the council's in-principle agreement on the Branxton substation siting.

Prysmian Group was selected as the exclusive preferred bidder by the EGL1 joint venture (National Grid Electricity Transmission and SP Transmission) to supply the HVDC submarine and underground cable system for Eastern Green Link 1. The scope covered roughly 400 km of submarine and land cable for a 2 GW, 525 kV HVDC link using extruded XLPE insulation, together with a short 400 kV HVAC cable connection at the Scotland end. Prysmian entered contract negotiations with the aim of concluding a final agreement later in 2023.

Ofgem published a conditional approval of the Final Needs Case (FNC) for the Eastern HVDC projects, approving the EGL1 Final Needs Case on 8 July 2022 (subject to obtaining necessary planning consents). This FNC decision recognised the national need for the Torness–Hawthorn Pit HVDC link to increase GB transmission capacity and supported progressing EGL1 through subsequent regulatory assessment and funding processes.

Ofgem issued a conditional decision in July 2022 approving the Final Needs Case for the Eastern Green Link 1 (EGL1) high-voltage direct current subsea link under its Large Onshore Transmission Investment (LOTI) mechanism, effectively greenlighting the £2.5 billion regulated project, subject to planning consents. This regulatory approval, for a 2GW HVDC connection between Torness in East Lothian and Hawthorn Pit in County Durham being developed by SP Energy Networks and National Grid Electricity Transmission, enabled the project to progress towards construction, with National Grid later reporting that onshore works were underway following Ofgem’s green light.

National Grid submitted the onshore planning application for the England elements of EGL1 to Durham County Council on 21 June 2022 (planning application that became referenced DM/22/01663/OUT). The application covered onshore infrastructure including a converter/substation near Hawthorn Pit and underground cable corridor from the landfall north of Seaham to the grid connection. The submission triggered the local planning consultation and determination process.

Landfall operations for EGL1 were planned to be completed as part of the offshore campaign and were to be delivered using Horizontal Directional Drilling (HDD) to install conduits beneath the intertidal zone at the Torness and Seaham/Hawthorn Pit landfall locations. HDD was selected to minimise intertidal works and environmental impacts; completion of landfall works was expected to be achieved during the broader subsea installation programme.