Final milestone for Shetland HVDC link complete following appointment of main contractors

The link, which will connect Shetland to the GB transmission system for the first time, is required to facilitate the connection of renewable electricity developments on Shetland and will also support Shetland’s future security of supply needs.

The project consists of an AC Substation at Kergord on Shetland, which is required for the connection of renewable electricity generators on Shetland, supporting the transition to net zero emissions. These works will be led by Siemens BAM, who have extensive experience constructing substations on behalf of SSEN Transmission across the north of Scotland. 

The power will then be converted from Alternating Current to Direct Current at a HVDC Converter Station, also at Kergord, before being transported around 270km via underground and subsea cable (257km) to a HVDC Switching Station at Noss Head, Caithness, in the north of Scotland. Global marine cable solution provider, NKT, will be responsible for the manufacture and installation of the subsea cable; with BAM Nuttall delivering all civil engineering works, including the construction of all buildings; and leading HVDC technology provider, Hitachi ABB Power Grids, delivering and commissioning the HVDC system.

The power will then be transported via the Caithness Moray HVDC link before being converted back to Alternating Current for onward transmission to meet the electricity demand requirements of homes and business across the north of Scotland and beyond. 

All four contractors played a major role in the construction of the Caithness Moray HVDC link, which has been operational since January 2019 and continues to provide highly reliable and efficient transmission of renewable electricity from the north of Scotland to areas of demand.

Enabling works are due to begin at Kergord and Noss Head towards the end of August, with full construction of the AC Substation, and HVDC Convertor and Switching Stations, due to commence in early 2021.  The subsea cable installation will take place in 2022 and 2023 following it’s manufacture.

Commenting on the major contract awards, Sandy Mactaggart, SSEN Transmission’s Director of Offshore Delivery, said: ‘We are delighted to have finalised contracts with our supply chain partners for the Shetland HVDC link, building on the experience and strong track record we have collectively established over recent years following the construction and operation of the Caithness Moray link. All four contractors are leading specialists in their field, building the high quality and reliable infrastructure required to meet Shetland’s future energy needs and contribute to UK and Scottish net zero targets. The Shetland HVDC link will deliver substantial socio-economic and environmental benefits to Shetland’s, Scotland’s and the UK’s economy, supporting hundreds of skilled jobs in the process as part of the green recovery from the coronavirus pandemic. With all major milestones complete, we now look forward to working closely with the Shetland and Caithness communities and other stakeholders throughout the construction and future operation of these critical national infrastructure assets.’

Niklas Persson, Managing Director of the Grid Integration at Hitachi ABB Power Grids, said: ‘Our advanced HVDC technology will bring clean electricity to consumers and enable the sharing of renewable resources by interconnecting Shetland with mainland Scotland.  We value this opportunity to further grow our partnership with SSEN Transmission. Being part of this innovative project is another example of Hitachi ABB Power Grids’ commitment to a sustainable energy future and a partner of choice for enabling a stronger, smarter and greener grid.’

Claes Westerlind, NKT’s EVP and Head of Solutions, said: ‘We are very pleased to be a partner for the Shetland HVDC link and to extend the good collaboration with SSEN Transmission from the Caithness Moray project. Together, we will provide a sustainable grid connection to Shetland and renewable energy supply from the island.’

Mark Tiernan, Siemens Director High Voltage Substations, said: ‘Siemens /BAM are delighted to be delivering the Kergord 132kV GIS substation through the well-established Siemens/BAM JV which has worked extensively across the network with the SSEN Transmission team  The project will use Siemens Energy’s world leading and innovative environmentally friendly gas insulated switchgear, which enables climate-neutral, reliable power transmission, free of harmful greenhouse gases, supporting SSEN Transmission’s commitment to reduce its own greenhouse gas emissions by one third by 2026.’

Adrian Savory, BAM Nuttall Chief Executive, said: ‘BAM is delighted to continue our collaborative relationship with SSEN Transmission on this project in Shetland, which has such strategic national importance. We look forward working closely with SSEN Transmission, ABB, NKT, and Siemens. And we’re excited to be providing infrastructure that contributes to Scottish net-zero targets and boosts the local economies in both Shetland and Caithness.’

All construction works are scheduled to be complete in December 2023, with energisation and full commissioning due to be complete in July 2024.  At its peak, in the summer of 2022, the project is expected to employ almost 250 people.

About SSEN Transmission

• SSEN Transmission, operating as Scottish Hydro Electric (SHE) Transmission plc, owns, operates and develops the high voltage electricity transmission system in the north of Scotland and remote islands. 
• SSEN’s strategic priority is to enable the transition to a low carbon economy through building the transmission infrastructure necessary to connect and transport renewable energy.
• Since the start of the current price control period, RIIO-T1, in April 2013, SSEN Transmission has invested over £3bn in the north of Scotland transmission system, supporting the growth of renewable energy across the region which has grown from 3.3GW to over 6.3GW as at 31 March 2020. 
• You can find out more information about the Shetland HVDC project on its dedicated website: www.ssen-transmission.co.uk/projects/shetland/  

Kergord infrastructure (HVDC Converter Station and AC substation) visualisation.