28th July 2026
A major piece of underground engineering at Dounreay has been completed, bringing the Orkney electricity link another step closer to reality and putting Caithness at the centre of a project designed to unlock hundreds of megawatts of renewable energy.
SSEN Transmission has announced the successful completion of horizontal directional drilling (HDD) at Dounreay, describing it as a major milestone in the construction of the Orkney Link.
The work involved installing an 830-metre underground duct, running from the Dounreay landfall area out beneath the seabed. The duct will eventually allow the subsea electricity cable to be pulled ashore without the need for major excavation through the coastal environment.
The significance of the work becomes clearer when the latest development is viewed alongside the much bigger Orkney Link project.
What has just been completed?
The Dounreay drilling was one of the more technically demanding parts of the project.
Rather than excavating a route from the shore towards the sea, horizontal directional drilling allows the duct to be installed underground before emerging beneath the seabed offshore.
The technique has several advantages, particularly in an environmentally sensitive coastal area.
SSEN says environmental specialists worked alongside the construction team to minimise impacts on marine and terrestrial environments.
The project also used remote-operated excavators for the final subsea section of the drilling, reducing the need for personnel to work directly in the marine environment.
The work was delivered by principal contractor RJ McLeod, with support from OCU Group, Lucion, Kirkwall-based Leask Marine and HDD specialists Peter McCormack & Sons.
The other end of the route is already prepared
An important part of the announcement is that the Dounreay work completes the horizontal directional drilling at both ends of the future subsea cable route.
Similar HDD work was completed at Warebeth in Orkney last year, where the drilled section was approximately 1,200 metres long.
That means the basic route for bringing the future subsea cable ashore has now been established on both sides of the Pentland Firth.
The next stages are therefore increasingly focused on the cable itself and the associated substations and onshore connections.
What exactly is the Orkney Link?
The project is much more than a cable under the Pentland Firth.
The Orkney–Caithness 220kV HVAC Subsea Link is being built to connect Orkney to the high-voltage electricity transmission network on the Scottish mainland for the first time.
It consists of several major elements:
A new Finstown substation in Orkney.
Approximately 14km of underground high-voltage cable from Finstown to Warebeth on Orkney's west coast.
Approximately 53km of subsea cable across the Pentland Firth from Warebeth to Dounreay.
A short underground cable connection on the Caithness side.
A new Dounreay West substation, connecting the new link into the existing transmission infrastructure at Dounreay.
The system is designed to transmit up to 220MW of new renewable electricity from Orkney into the wider electricity network.
That is a substantial amount of electricity for an island community.
Why does Orkney need the connection?
Orkney has an unusually strong renewable-energy resource.
The islands already have significant onshore wind generation and have also been at the forefront of developing marine-energy technologies.
The problem is that producing renewable electricity is only half the equation.
You also need a sufficiently powerful electricity network to take that electricity away from where it is generated.
The new transmission link is intended to remove one of the major constraints on Orkney's ability to develop additional renewable generation.
Instead of renewable projects being limited by the capacity of the existing electricity network, the new transmission connection will provide a much larger route into the mainland transmission system.
And that is where Dounreay comes in
For Caithness, the project is particularly significant because Dounreay becomes the mainland gateway for the Orkney connection.
The new Dounreay West substation will connect the Orkney link to the existing transmission network at Dounreay.
The new substation will step the voltage up to 275kV for connection into the existing infrastructure.
That makes Dounreay much more than simply the location where a cable comes ashore.
It becomes an important part of the infrastructure allowing renewable electricity generated in Orkney to reach electricity demand centres elsewhere in Scotland and beyond.
A project years in the making
The Orkney connection has a surprisingly long history.
Ofgem gave conditional approval to the 220MW transmission link in 2019. At that stage, the project was estimated to cost around £260 million, with completion originally envisaged much earlier than the current programme.
The project subsequently went through further regulatory assessment and development.
SSEN's project information now identifies the scheme as being in its construction phase, with the eventual operational phase still to come.
SSEN's project documentation has previously indicated a programme leading towards completion of cable installation in 2027 and commissioning and energisation in 2028.
So the drilling milestone announced in July 2026 should be viewed as part of a much longer infrastructure programme rather than the final stage of the project.
Why the project matters beyond Orkney
It would be easy to regard the Orkney Link as an Orkney project that happens to land at Dounreay.
That would underestimate its importance.
The electricity system in the north of Scotland is undergoing a major transformation.
Large amounts of renewable generation are being developed in areas where electricity demand is relatively low compared with the potential amount of power that can be generated.
That creates a fundamental infrastructure problem.
How do you move the electricity from remote areas of Scotland to where it is needed?
The answer requires substantial investment in transmission infrastructure.
The Orkney Link is one part of that wider process.
What could it mean for Caithness?
There are several potential benefits for the area.
Construction and supply-chain opportunities
Major infrastructure projects generate demand for:
construction workers;
engineering services;
transport;
accommodation;
catering;
plant hire;
security;
materials;
environmental services;
specialist contractors.
SSEN has previously held "Meet the Buyer" events specifically to encourage local businesses to participate in the supply chain.
For Caithness businesses, the important point is that the economic activity doesn't necessarily end when the construction machinery leaves.
A larger electricity transmission network can make the area more attractive for future energy developments.
Strengthening the energy infrastructure
Caithness is already becoming an important part of Scotland's renewable-energy infrastructure.
Dounreay's position gives it strategic importance because it can act as a connection point between electricity generated around the northern islands and the wider mainland network.
That could become increasingly valuable as Scotland adds more wind generation and attempts to move towards a lower-carbon electricity system.
Supporting renewable development
The biggest prize is potentially on the Orkney side.
The new connection is designed to enable up to 220MW of additional renewable electricity to connect to the national grid.
In other words, the transmission project isn't primarily about producing electricity.
It is about creating the network capacity that allows other projects to produce it.
That distinction is important when considering Scotland's energy strategy.
There is another side to the story
The project also illustrates the enormous infrastructure challenge involved in Scotland's energy transition.
It is one thing to announce large amounts of new wind and marine generation.
It is quite another to build the substations, cables and transmission network needed to transport that electricity.
The Orkney project involves:
Finstown → 14km of underground cable → Warebeth → 53km subsea cable → Dounreay → new substation → existing transmission network.
That is a substantial engineering undertaking simply to connect an island group to the mainland grid.
It also demonstrates why the UK's transition to renewable electricity requires very large investment in infrastructure that consumers may never see.
A milestone beneath the ground
The completion of the Dounreay HDD works may not be as visually impressive as a new wind turbine or a large electricity pylon.
Much of the work is now hidden underground.
But that is precisely what makes the milestone important.
The 830-metre duct now provides the route through which the future subsea cable can eventually come ashore at Dounreay.
Combined with the completed HDD works at Warebeth, the project has now overcome one of the most difficult engineering challenges at either end of the Pentland Firth connection.
For Caithness, it is another sign that the region is becoming increasingly important to Scotland's future electricity infrastructure.
What happens next?
The drilling is complete, but there is still plenty of work ahead.
Construction continues on the Dounreay West substation, while work is also progressing on the Orkney infrastructure and the cable landfall arrangements.
SSEN has also indicated that construction work at Warebeth is progressing, including the works needed to bring the subsea cable ashore and create the underground joint bay.
The major remaining challenge will be installing and connecting the subsea cable itself.
If the project remains on its current programme, the eventual objective is to have the connection commissioned and energised in 2028.
From Dounreay's past to Scotland's energy future
There is something particularly appropriate about the location of this project.
For decades, Dounreay was associated with Britain's nuclear research and development programme.
Now the same part of Caithness is becoming involved in a very different chapter of Britain's energy story.
The Orkney Link will not generate electricity itself.
Instead, it will provide the infrastructure required to move renewable electricity into the national network.
And that may ultimately be its greatest significance.
The 830 metres of drilling completed at Dounreay might look like a relatively small part of a much larger project, but it represents another step towards turning the far north of Scotland into a major part of the country's renewable-energy network.
For Caithness, the Orkney Link is therefore not simply an Orkney project with a cable landing at Dounreay.
It is another piece of the infrastructure that could help shape the economic and energy future of the north of Scotland.
Orkney Connection