A £660 million project to connect Shetland to the national electricity grid on the mainland for the first time has reached a new “significant milestone”.
Scottish and Southern Electricity Networks (SSEN) has hailed the start of work installing a 162 mile subsea cable system between Noss Head in Caithness and Weisdale Voe in Shetland.
The project – due to complete next year – will help ensure the islands future supply of clean, low-carbon power.
Shetland is currently an “islanded” electricity network, which means all electricity is met from on-island sources, primarily the diesel powered Lerwick Power Station.
Energy regulator Ofgem approved SSEN Transmission’s huge power link cable from the Shetland Isles to the Scottish mainland in 2020.
The Shetland HVDC Link project is thought to be “crucial” to the UK’s energy system, connecting projects such as SSE Renewables’ giant Viking onshore wind farm as well as the Shetland-based Orion (Opportunity, Renewables, Integration, Offshore Networks) scheme.
A specialist cable laying vessel, the NKT Victoria and its crew are readying themselves to start laying 37 miles of high voltage direct current (HVDC) subsea cable system as part of the next stage of installation.
The first 62 mile length of cable was successfully installed in July last year, with NKT Victoria laying the cable from Noss Head.
Now in waters off Weisdale Voe, the vessel lowered the end of the cable which was then successfully pulled onto shore via previously installed ducts by a winch located on the shoreline.
Once secured in the transition joint bay, the offshore cable will be jointed to the previously installed HVDC land cable which will then connect to SSEN’s Kergord substation.
The NKT Victoria will make her way south out to sea along the designated cable route, slowly lowering the cable system onto the seabed.
Once the cable is in place, it will be trenched into position using a construction support vessel with a specialist subsea jet trencher, which will ensure the cables are buried to the correct depth.
Rock placement will also take place at some sections to ensure the cables are protected where trenching is not possible.
The third and final campaign will take place later this year, which will complete the link between the first and second campaigns in the North Sea to join all three campaigns together and complete the full link.
Another ‘major and hugely symbolic milestone’
SSEN Transmission’s Shetland HVDC Link project director John Scott said: “The arrival of NKT Victoria in Shetland signals yet another major and hugely symbolic milestone in the Shetland HVDC Link project, and it’s been great to see the cable make landfall in Shetland as the vessel begins her voyage into the North Sea and kick off the next cable campaign.
“The installation of the subsea cable system is complex and requires significant planning to reach this point, and working with subsea cable experts NKT has enabled this process to take place reliably, safely and to the highest standard.
“The second cable campaign marks an exciting step in the project for SSEN Transmission and our contractors, and we look forward to the completion of this phase of the subsea cable campaign over the coming weeks.
“The Shetland HVDC Link is crucial to transporting clean, renewable energy to where it is needed most, ultimately helping us achieve a network for net zero; alongside securing Shetland’s future security of supply.”
Claes Westerlind, executive vice president and head of the NKT high-voltage factory in Karlskrona, Sweden, said: “I am very satisfied that we continue the good collaboration with SSEN Transmission by leveraging our extensive experience within HVDC-technology to enable low-carbon power supply to Shetland.”
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