IN Brief:
- Eastern Green Link 2 is a £4.3bn, 505km HVDC scheme with planned transfer capability of 2GW between Scotland and England.
- Peterhead has completed its first converter-building steel frame and AC hall, while Wren Hall is advancing foundations and buildings.
- More than 25km of Yorkshire haul road and 8km of trenching are complete, with cable manufacture and landfall work continuing.
SSEN Transmission and National Grid Electricity Transmission have marked two years of construction on Eastern Green Link 2 (EGL2), with permanent converter-station buildings now rising at both ends of the planned electricity link between Scotland and England. The £4.3 billion scheme is designed to move up to 2GW of power over a 505km high-voltage direct current (HVDC) connection from Peterhead in Aberdeenshire to the Drax area in Yorkshire. The latest works update, issued on 6 November, records progress in converter-station structures, underground cable preparation and the transition points between land and sea.
At Peterhead, the first converter building’s steel frame and the first alternating current (AC) hall have been completed, with concrete works finished for both transformer buildings. Cladding is continuing across the converter-station site. These are identifiable construction milestones rather than evidence that converter equipment has been installed, tested or energised. The project partners say the station has progressed from formation of its construction platform to permanent structures that will accommodate the electrical systems needed to connect the HVDC link with the existing high-voltage network.
Foundations and permanent structures are also progressing at Wren Hall, near Drax in Yorkshire. The converter building will house power-electronic equipment that changes direct current from the cable into alternating current suitable for the surrounding network; Peterhead’s station will perform the corresponding conversion at the Scottish end. Transformer halls, cooling arrangements, protection systems, controls and AC switchgear must be integrated around those converters. Civil progress creates the spaces for the equipment, while the electrical installation and testing programme follows a separate sequence.
High-voltage direct current transmission is suited to EGL2’s long submarine route. With high-voltage AC subsea cables, capacitance produces charging current over the entire length, consuming part of the current-carrying capability even when the cable is transferring little useful power. HVDC avoids that alternating charging cycle along the cable, although the terminals require complex converter equipment and consume energy themselves. The proposed 2GW rating is the link’s transfer capability, dependent on the connected grid and the availability of both converters, rather than new generating capacity at either site.
Work is progressing along the Yorkshire land cable corridor, where nearly 70km of ground is being prepared for underground cable installation. Since enabling works began in August 2025, construction teams have installed more than 25km of haul road, completed more than 8km of cable trenching and carried out nine horizontal directional drills. The roads provide access for construction vehicles and cable deliveries, while the trenching creates the route in which the cable system can subsequently be placed. The amount of trench dug should not be read as an equivalent length of finished, electrically tested cable.
Horizontal directional drilling is being used at locations where a buried crossing can avoid an open excavation through an obstacle or sensitive area. At Peterhead, drilling beneath the U66 road has been completed to provide ducts for a new 400kV connection from the converter station to the existing Peterhead substation. That connection is part of the AC transmission interface and is separate from the long HVDC export route. Its final electrical role will depend on installation and testing of the required cables and station equipment, not simply completion of the duct works.
The offshore transition works have reached different stages at the two ends of the route. The Sandford Bay landfall drill at Peterhead is complete, while drilling at Fraisthorpe near Bridlington remains under way. These landfalls must enable cables to pass between the offshore route and their onshore sections without relying on an exposed excavation across the entire coastal crossing. Manufacturing of the main cables and specialist HVDC equipment is continuing away from the sites, demonstrating that civil progress and factory production are running in parallel rather than as one continuous sequence.
After the permanent buildings are weatherproofed, installation of converter valves, transformers and their auxiliary systems will become central to progress. Cable laying will require jointing, terminations and insulation testing, followed by integration with the protection and control systems at both terminals. The link will then need coordinated commissioning across the Scottish and English network interfaces before its designed 2GW capability can be used. These activities involve different trades, specialist equipment and outage arrangements from those employed for earthworks, foundations and structural steel.
Approximately three million working hours have been recorded across the EGL2 programme, according to the partners. Those hours span work on converter stations, landfalls and the cable corridors, as well as supporting operations. The figures show the scale of simultaneous construction along a geographically dispersed transmission project. They also emphasise the need to coordinate factory-produced cables and electrical equipment with construction progress, since finished components cannot simply be installed before access, foundations and cable ducts are ready.
The partners describe EGL2 as a means of strengthening north–south electricity transmission, allowing more power produced in Scotland, including renewable generation, to reach demand centres elsewhere in Great Britain. Its usefulness will depend on the wider AC network at both ends as well as the HVDC equipment itself. A 2GW interconnector cannot independently remove all constraints on the connected networks, and the amount of power it carries at any moment will be governed by dispatch conditions, system limits and equipment availability. Further construction is scheduled through 2027, with cable installation and integration still ahead.
Fionán Doonan, EGL2 project director, highlighted the emergence of permanent converter structures at Peterhead after two years of work. The next programme stages include completion of those buildings, further landfall drilling, continued cable manufacture and installation of the electrical systems at each end. Progress is measurable in completed foundations, installed ducts and manufactured equipment, while the eventual test of the investment will be successful operation of the 505km transmission link between Peterhead and Yorkshire.
