IN Brief:
- A temporary construction compound at Faebait is due to start on 31 August and take approximately four weeks.
- The compound will support later work on the Western Isles HVDC mainland underground cable route.
- The wider 1.8GW connection includes 81km of subsea cable and roughly 80km of underground mainland HVDC cable.
SSEN Transmission is preparing to establish a temporary construction compound at Faebait near Muir of Ord as enabling work continues along the mainland section of the 1.8GW Western Isles HVDC connection.
Work is due to begin on 31 August and is expected to take approximately four weeks. The compound will be located slightly west of Faebait Farm, close to the planned cable alignment, providing a working area for personnel, plant, and materials required during later phases of underground-cable construction.
Current working hours are planned from 7.30am to 6pm, Monday to Friday, without weekend activity. SSEN Transmission does not expect road traffic management to be required for construction of the compound because the immediate works will take place within the landowner’s area away from the public road.
The activity is comparatively small beside the converter stations and subsea cable at the centre of the project, but temporary compounds are necessary before long underground sections can be installed efficiently. Similar enabling work is progressing at several points along the mainland route, creating the logistics chain needed for the later cable programme.
A long HVDC route needs repeated working bases
The Western Isles project is intended to connect renewable generation around Lewis and the wider island group with Great Britain’s transmission system. Existing network capacity serving the islands is already constrained, preventing further generation from connecting without substantial reinforcement.
The planned solution uses high-voltage direct current technology rated at 1.8GW. On Lewis, a converter station and AC substation near Stornoway will connect to approximately 4km of underground HVDC cable running to the landfall at Arnish Point.
An 81km subsea cable will cross from Arnish Point to Dundonnell on the Scottish mainland. From there, approximately 80km of underground HVDC cable is planned across the Highlands to another converter station near Beauly, where the link will interface with the wider alternating-current transmission system.
That geography makes logistics an engineering issue rather than a simple construction convenience. Underground high-voltage cable installation requires successive work fronts for civil engineering, cable handling, specialist plant, workforce facilities, materials, testing, drainage, and local access.
Different sections also require different construction methods. Road crossings, watercourses, constrained ground, and environmentally sensitive areas can require trenchless techniques rather than continuous open excavation, increasing the importance of positioning compounds and access routes before specialist equipment arrives.
The Faebait site is another part of that sequence. Establishing a working base close to the planned alignment reduces daily movement of equipment and gives later cable teams a controlled area from which to support civil and electrical activity along the route.
The link addresses a physical generation constraint
The current 1.8GW design is substantially larger than an earlier 600MW Western Isles connection concept. The higher rating was developed as national network planning incorporated a larger pipeline of onshore and offshore renewable generation around northern and western Scotland.
HVDC is well suited to long subsea links because power flows can be controlled precisely and transmission losses remain manageable over distances where conventional AC cable systems become more difficult. The converter stations at either end carry much of the electrical complexity by converting between direct current on the long-distance link and alternating current on the surrounding transmission network.
Those stations require extensive control, protection, cooling, filtering, auxiliary supplies, communications, and reactive-power management. The cable may provide the physical connection across sea and land, but the converters determine how that link behaves as part of the wider power system.
For the Western Isles, the transmission constraint affects more than renewable export. SSEN Transmission expects the new connection to strengthen island security of supply and reduce reliance on diesel generation while creating sufficient capacity for additional renewable projects.
The scheme forms part of a much broader programme of transmission investment across northern Scotland, involving new substations, overhead lines, converter stations, and other reinforcement required to move renewable electricity from resource-rich regions towards larger demand centres.
Large HVDC programmes naturally attract attention when major cable, converter, or construction contracts are announced, yet delivery relies on smaller enabling works being completed in sequence. Access, compounds, vegetation management, surveys, drainage, and civil preparation all have to be in place before specialist electrical installation can proceed efficiently.
The Faebait compound will not add a single megawatt of transmission capacity by itself. It does move another section of the mainland route towards the stage where cable installation can begin, turning a planned 1.8GW connection into a chain of physical construction sites stretching from Lewis, beneath the Minch, and across the Highlands.
That progression is now the useful measure of the project. Converter ratings and cable lengths define the engineering ambition, but compounds such as Faebait show whether the route is actually being prepared for the sustained civil and electrical work required to put the link into service.
