Shetland HVDC Link, UK

Aiming to create the first clean, renewable energy connection between the remote Shetland Islands archipelago and the Scottish mainland, the Shetland Island HVDC Link is a major step forward in the UK’s green transition as it strives to meet am- bitious net zero and energy security targets. It will also integrate the new 443 MW Viking Energy Wind Farm with the Great Britain electrical grid.

Once fully operational in 2024, the 103-turbine Viking Energy Wind Farm will utilise Shetland’s famously windy weather conditions to generate the clean energy needed to power approximately 500.000 homes – including every household on the Shetland Islands. This green link will be the key to fully unleashing Shetland’s natural wind energy resources from what will soon be the UK’s most productive onshore wind farm.

As the turnkey supplier for the complete HVDC cable system, NKT was responsible for design and manufacturing the cable system, onshore cable installation, offshore cable-laying with the NKT Victoria, jointing and termination works, and culminating with testing.

There was one more crucial consideration for this project: leaving a minimal footprint on the land. The Islands are populated by unique local flora and fauna, such as ground-nesting birds and sea otters. NKT also needed to prevent disruption to the many types of coastal wildlife that call the Shetland Islands home.

This project underscores NKT’s expertise and capability to efficiently manage complex, large-scale turnkey projects that demand meticulous planning and adherence to the highest standards for both power cable quality and environmental stewardship.

Created in close collaboration with SSEN Transmission, at the heart of this turnkey project is a 320 kV HVDC interconnector, which will play a critical role in supporting the integration of renewable energy in the UK.

NKT’s HVDC solution for this power cable project is comprised of two power cables, stretching 253 km offshore and 10 km onshore. The link can efficiently transmit up to 600 MW of renewable energy over the long distance between Shetland and the Great Britain electrical grid, unlocking the Islands' renewable potential and also securing a continuous supply of homegrown, low-carbon power.

A consistent environmental focus was the cornerstone of the project, which is evident in every phase, from manufacturing, installation and cable-laying, to the comprehensive implementation of wildlife safeguarding measures.

Leveraging our extensive experience within the field of HVDC technology, the reliable high-voltage cable system was designed and manufactured at NKT’s industry-leading, high-voltage cable production facility in Karlskrona, Sweden. This factory operates entirely on renewable electricity, reducing the carbon footprint of the HVDC cable system.

The conductor is made from stranded aluminum wires and is protectively armoured to withstand the harsh elements in the Islands and the North Sea.

After the production of the offshore cables was completed in Karlskrona, we loaded them onto our cable-laying vessel, the NKT Victoria, one of the world’s most energy-efficient vessels of its kind, for the long voyage to the Shetland Islands.

Cable-laying was performed in three campaigns to ensure safety and accuracy, with the project’s last step being the jointing of the cables to complete the full ≈ 263 km submarine HVDC link.

We took thorough measures to safeguard the Islands’ wildlife throughout the project. An environmental specialist was employed on-site for a year to oversee monitoring and protection of the resident ground-nesting birds and otters, demonstrating that it is possible to achieve a green transition while prioritising and preserving local wildlife.

The project was not only completed on-time and within-budget, but it also set a benchmark for upholding the highest standards for environmental sustainability and biodiversity conservation.