Caithness - Moray HVDC Link
Domestic ReinforcementOperationalGB1,200 MW320 kV160 km2018
Status:Operational
Capacity:1,200 MW
Project Company:
Scottish Hydro Electric Transmission Plc (SSEN Transmission)
Type:domestic reinforcement
Website:www.ssen-transmission.co.uk
The Caithness–Moray HVDC link is a GB domestic VSC-HVDC transmission reinforcement connecting Spittal in Caithness to Blackhillock/Portgordon in Moray, delivered by SSEN Transmission (formerly SHE Transmission). Commissioned and energised in late 2018 and declared operational in early 2019, the project was a ~£1.1bn investment to strengthen the north of Scotland...
Supply Chain (20)
Project Timeline (36)
5 Feb 2025Operations Other
Hitachi Energy commenced an EnCompass Long‑Term Service Agreement (LTSA) to provide long‑term maintenance, cyber‑security services, inspections and other lifecycle services for the Caithness‑Moray and Shetland multi‑terminal HVDC system. The LTSA formalised Hitachi Energy’s role in operating and maintaining the multi‑terminal VSC HVDC infrastructure to support reliable power transmission.
21 Jul 2023Converter Supplier Selected
Hitachi Energy was publicly selected by SSEN Transmission under a multi‑project framework announced on 21 July 2023 to supply onshore HVDC converter stations for a series of large HVDC links in northern Scotland. The announcement named projects including Caithness‑Moray and Shetland and positioned Hitachi Energy to supply VSC HVDC converter technology and related systems as part of SSEN's programme to integrate large‑scale renewables.
Nov 2022Onss Commissioned
The Caithness HVDC switching station at Noss Head was completed and moved into the operational phase in November 2022, enabling the HVDC subsea cable between Caithness and Moray to connect into the onshore transmission network. SSEN Transmission documented the switching station as operational (Stage 5) and published a completion video in November 2022; Hitachi Energy referenced the successful completion of the Caithness–Moray HVDC subsea link in its project summaries.
21 Jun 2022Operations Other
SSEN Transmission concluded and awarded a long‑term service agreement for the Caithness, Moray & Shetland multi‑terminal HVDC link to Hitachi Energy UK Limited on 21 June 2022. The single‑source contract (value £28,210,957.17 excluding VAT) covered mobilisation, scheduled maintenance, emergency call‑out, unscheduled maintenance and cyber‑security services for the HVDC equipment, with SSEN citing the proprietary nature of the HVDC technology as the rationale for sole sourcing.
27 Jul 2020Late Development Other
SSEN Transmission awarded the contract for the design and construction of the Caithness HVDC Switching Station at Noss Head to principal contractor BAM Nuttall Ltd on 27 July 2020. The award appointed the principal contractor responsible for delivering the onshore switching station works that form part of the Caithness–Moray HVDC link.
2 Oct 2019Cable Installation Complete
NKT announced completion of the turnkey 320 kV HVDC submarine and underground power cable system for the Caithness–Moray link, confirming finalisation of cable system works and noting the performance of the cable-laying vessel NKT Victoria used during the installation campaign.
29 Mar 2019Other Permit Submitted
A Marine Licence variation application was submitted on 29 March 2019 seeking amendments to existing Caithness‑Moray marine licences to permit additional rock placement (tens of thousands of tonnes of rock), inclusion of Controlled Flow Excavation (CFE) as an installation method, updates to the cable burial plan and the potential installation of up to 1,000 m of cable protection system (e.g., Cast Iron Shell or Tekmar). The application supported remediation and protection works following post‑installation assessments.
5 Feb 2019Other Permit Submitted
A Controlled Flow Excavation / Rock Placement Marine Protected Areas assessment for the Caithness–Moray HVDC Link was prepared and published in February 2019 to support marine works. The assessment documented proposed seabed intervention methods (CFE and rock placement), considered potential sediment and ecological effects on nearby MPAs, and formed part of the project’s marine consenting and construction planning documentation.
11 Jan 2019First Power
SSEN Transmission completed construction, commissioning and energisation of the Caithness–Moray HVDC link and brought the link into service on 11 January 2019, enabling up to 1,200 MW of capacity to transmit renewable generation from northern Scotland into the GB transmission system.
11 Jan 2019Onss Commissioned
The land-based 320 kV HVDC converter stations at Blackhillock and Spittal were commissioned as part of the Caithness–Moray project’s energisation, with Hitachi Energy (formerly ABB business) responsible for design, supply and commissioning of the converter equipment supporting the link’s operational service.