Onshore Construction

This page features the latest updates on Sofia's onshore construction progress and upcoming activity, as well as details of the main contractors that will ensure the successful delivery of  the project's onshore electrical infrastructure, from landfall to the National Grid substation.


Onshore Map


The power produced by Sofia will be transmitted by offshore cables that arrive on land at a site between Redcar and Marske-by-the-Sea. Each offshore cable will connect to an onshore buried cable that will run seven kilometres to a new converter station to be constructed on a site adjacent to the Wilton Complex. Further buried cables will transport the power two kilometres from the converter station to the existing substation at Lackenby, where it will feed into the national grid. Onshore construction works began at the site of the converter station in June 2021, and onshore project-related activity will continue until early 2025.


Onshore converter station  

Civil engineering contractors contracted to GE's Grid Solutions have been onsite since spring 2022, readying it for the installation of the converter station's state-of-the-art electrical infrastructure. Work is making visible leaps forward with the converter station buildings now almost weathertight and ready for fitting out.

Sofia is keen to minimise disruption to those living nearest the site and part of this has involved re-shaping the northern of two mounds that separate the converter stations’ site from Lazenby Village. As well as being reshaped, it has also been planted with trees, shrubs and wildflowers. The second phase of reshaping, on the southern mound, is now underway. The reshaped mounds will be an improved barrier to the construction activity and will visually screen the two new converter stations and the Wilton International site. 

400kV AC cable route

A second GE contractor, VolkerInfra has carried out duct installation for the two-kilometre 400kV AC cable route from the converter station to the National Grid substation at Lackenby.

Cable route

The onshore civil engineering work for the export cable route is progressing at pace. J. Murphy & Sons Ltd. has completed most of the duct installation in readiness for the project’s export cables to be pulled through. Work on the construction of tunnels which will be used to take the export cables underneath the railway bridge at Redcar Road has recently been completed, with transition bays either side of the tunnels now under construction. 

Regular drone surveys of the converter station and both cable corridors will be carried out throughout the works to monitor progress.


At the landfall the teams are working on the one-kilometre horizontal directional drills from the construction compound opposite the beach near Marske-by-the-Sea, Teesside. Drilling work was on hold over winter but the site has remobilised and the final drills are now complete.


Mid 2021

Start of enabling works to prepare for the construction of the converter station.

Start of work on the mounds on-site - to increase the screening of the converter station site from the village of Lazenby.

Late 2021

Enabling works completed at the converter station site.

Work at the existing National Grid Lackenby Substation begins.

Early 2022

Construction of Sofia’s onshore converter station begins.

Start of works along the cable corridor from landfall to Lackenby Substation. Trenching and duct laying underway.

Mid 2022

Start of two years construction activity at the landfall between Redcar and Marske-by-the-Sea, including horizontal directional drill under the beach to lay ducts for the offshore cable.

Mid 2023

Start of work to install the export cables from shore to the converter station.

Installation of AC cables from the converter station site to the National Grid substation.


Mid 2024

Completion of construction works at the landfall site.

Completion of the installation of cables from shore to the converter station.

Late 2024

Sofia connected to the national grid. All work, including reinstatement, completed along the cable corridor between the converter station and substation, and at the substation itself.

Onshore converter station construction completed.

Completion of the mounds screening the converter stations.

Early 2025

Completion of reinstatement of cable corridor from shore to the converter station site.


All relevant plans relating to the project's onshore construction, including Design, Landscape, Fencing and Drainage, will be submitted to Redcar & Cleveland Borough Council for approval prior to work starting. The button below takes you to a list of all the available documents and their reference numbers so you can find them in the Planning Register of the Council website.



Starting onsite in 2022, GE's Grid Solutions will be responsible for the construction of the onshore converter station.

GE's Grid Solutions

Prysmian Group will design, supply, install and commission Sofia's HVDC export link including 15km of onshore cables and installation work.


Prysmian Group


Jones Bros Civil Engineering UK will deliver the enabling works package for the onshore converter station platforms for both Sofia and Dogger Bank C.

Jones Bros. Civil Engineering

Kier is carrying out the onshore converter station civils construction package on behalf of GE's Grid Solutions.


VolkerInfra will design, supply and install the 400kV AC cable between Sofia's onshore converter station and National Grid's Lackenby Substation.


BakerHicks will design the Sofia onshore converter station and carry out related activities.


J. Murphy & Sons will design and deliver the onshore export cable civil works in relation to both Sofia and neighbouring project Dogger Bank C.

Murphy Group