Supplier agreement signals major step forward for subsea HVDC projects

SSEN Transmission_SSEN Transmission and NKT at the supplier agreement signing.jpg

SSEN Transmission has taken a major step forward in the delivery of two major High Voltage Direct Current (HVDC) transmission connection projects, after securing agreements with Cable Supplier NKT.

The agreements will see NKT proceed with the initial works on projects connecting Lewis on the Western Isles to Beauly on the Scottish mainland and Spittal in Caithness to Peterhead in Aberdeenshire.

The projects form a key part of SSEN Transmission’s infrastructure development programme, a £20bn investment that will deliver major upgrades to the electricity transmission network in the north of Scotland that will enable the connection and transportation of renewable energy around Great Britain.

The Western Isles Connection project will see the installation of 81km of subsea cable and a further 80km of underground cable between the HVDC site on Lewis and the corresponding HVDC site at Fanellan on the mainland, while the Spittal to Peterhead connection comprises a 150km subsea cable. Both projects will also require land cable sections and new associated HVDC Convertor Stations.

Sandy Mactaggart, Director of Offshore Delivery at SSEN Transmission, said:
“We are delighted to have secured agreements with our supply chain partner NKT to help deliver the cables needed for the Western Isles and Spittal-Peterhead HVDC connections, an important step supporting the timely delivery of these projects. 

“Recognising the unprecedented global demand for HVDC technology, we have acted with pace to secure these key components at the earliest opportunity - and we’re now looking forward to building on our long-established and strong working relationship with NKT.

“We are particularly pleased to be working with NKT on the delivery of the crucial Western Isles Connection Project. Having been involved in efforts to connect the Western Isles for several years, NKT have demonstrated a real understanding of the project’s importance in enabling the development of renewable energy in and around the Western Isles and the associated benefits this will deliver for the local community, and it will be great to work together to help realise that opportunity.”

Darren Fennell, EVP & Head of HV Solutions Karlskrona in NKT, said:
“We are very satisfied taking the next steps for the projects and continuing the long-term collaboration with SSEN Transmission to strengthen the interconnection of the Scottish power grid.

“With our extensive experience in large turnkey HVDC projects, we remain committed to supporting the decarbonisation of the power system in Great Britain.

“The agreement is a statement of the exceptional collaboration with SSEN Transmission on interconnector projects like the Caithness-Moray HVDC Link and the ongoing Shetland HVDC Link.”

 

As Background

Extensive studies have confirmed the need for an offshore transmission connection to the Western Isles and between Spittal and Peterhead. The links will enable the efficient high volume power transmission from generators in the far North and West of Scotland to the network connection points.

Both projects are required to connect onshore and offshore wind in and around the Western Isles and North Sea to the National Grid Transmission System, maximising the significant renewable potential of Wind Energy.

Both connection projects will utilise 525kv HVDC cable with Bi Pole design due to the long conductor lengths, in addition on the Spittal to Peterhead connection an additional DMR (dedicated metallic return) cable will be installed.

Western Isles Connection Project

Project Elements include:

  • High Voltage Direct Current (HVDC) Converter Station and an Alternating Current (AC) Substation located near Arnish Point Stornoway, Lewis
  • Circa 4km of underground HVDC cable from the new HVDC converter station and AC substation to the landfall at Arnish Point, Stornoway
  • 81km of HVDC subsea cable from Arnish Point, Stornoway to Dundonnell on the Scottish mainland
  • Circa 80km of onshore underground HVDC cable from Dundonnell to a mainland HVDC Converter Station near Beauly
  • A mainland HVDC Converter Station near Beauly

Spittal – Peterhead Connection Project

Project Elements include:

  • High Voltage Direct Current (HVDC) Converter Station and an Alternating Current (AC) Substation located near Spittal.
  • Circa 20km of HVDC on land cable from Spittal Convertor Station to Landfall Transition of Subsea Cable
  • 150km of HVDV subsea cable from Spittal to Peterhead on land transitions.
  • Circa 15km of HVDC on land cable from Peterhead Convertor Station to Landfall Transition of Subsea Cable
  • High Voltage Direct Current (HVDC) Converter Station and an Alternating Current (AC) Substation located near Peterhead.