Project Type: Transmission reinforcement
Location: Western Isles, Highland

Contact Details

Liaison Manager

Lisa Marchi
Title: Community Liaison Manager
Telephone: 01463 728072
Mobile: 07825 015507
Address: 10 Henderson Road, Inverness, IV1 1SN

Land Manager

Ali MacLeod
Title: Land Manager
Mobile: 07500 912996
Address: 10 Henderson Road, Inverness, IV1 1SN
Status: Early Development

Arnish HVDC Converter Station and GIS Substation Pre Application Consultation

SSEN Transmission is intending to submit a planning application to Comhairle nan Eilean Siar for a new High Voltage Direct Current Converter Station (HVDC) and Gas Insulated Substation (GIS) at Arnish Point in Stornoway. As such we are hosting a public exhibition to provide further details about this project.


The consultation event will be taking place on:
Tuesday 21st June
15:00 – 19:00
Caberfiedh Hotel
Manor Park,
Perceval Road

SSEN Transmission would like to extend an invitation to local members of the community and interested parties to attend the exhibition to discuss our plans with the project team and let SSEN Transmission know their views on the proposal.


Once planning applications have been submitted, the public will have an opportunity to make formal representations to Comhairle nan Eilean Siar for the proposed Arnish HVDC Converter Station and GIS Substation before a decision is made on our application.

Project overview

We are proposing to construct a High Voltage Direct Current (HVDC) connection between the island of Lewis and the Scottish mainland. The Western Isles Connection will be used to transmit electricity generated by renewable developments on the Western Isles to areas of demand around our towns and cities.


Why is the project required?

As the transmission licence holder in the north of Scotland we have a duty under Section 9 of the Electricity Act 1989 to facilitate competition in the generation and supply of electricity. We have obligations to offer non-discriminatory terms for connection to the transmission system, both for new generation and for new sources of electricity demand.

The aim of the project is to enable renewable energy to connect to our transmission network. Under our Network Operators Licence this connection should be efficient, co-ordinated and economic, whilst having the least possible impact on the environment.

The Western Isles is home to some of Scotland’s greatest wind resource and following the growth in small-scale renewable electricity generation over recent years, the existing Western Isles electricity network is at full capacity meaning no further generation can connect without significant network reinforcements. The connection, which is expected to bring local and national socio-economic benefits, is required to connect renewable electricity generators on the island to the main GB transmission system, maximising the significant renewable potential of the Western Isles.

Project elements

The project is made up of four main elements:

  • High Voltage Direct Current (HVDC) Converter Station and Gas Insulated Substation (GIS) located at Arnish Point, Stornoway.
  • 81km of HVDC subsea cable from Arnish Point, Stornoway to Dundonnell (Scottish Mainland).
  • Circa 75km of underground HVDC cable from Dundonnell to mainland HVDC Converter Station.
  • Underground AC (Alternating Current) cable from mainland HVDC Converter Station to the mainland Transmission System.

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The data in this map is provided for indicative purposes only and may be subject to change. Scottish Hydro Electric Transmission plc do not accept responsibility for its accuracy, completeness or validity. The data should not be copied, reproduced or utilised externally without permission.

Who is Scottish and Southern Electricity Networks?

Scottish and Southern Electricity Networks is the trading name of Scottish and Southern Energy Power Distribution Limited, Scottish Hydro Electric Transmission plc, Scottish Hydro Electric Power Distribution plc and Southern Electric Power Distribution plc.

How are Transmission network upgrades paid for?

Investments in projects are made by SHE Transmission plc. Electricity transmission companies are authorised to recover the costs of such investments through 'use of system' charges which are levied by National Grid Electricity Transmission plc on generators and suppliers of electricity. Suppliers recover their costs from all electricity customers. In order to protect the interests of customers, the transmission companies have to demonstrate to the energy regulator, Ofgem (Office for Gas and Electricity Markets) that proposed investments are necessary, are efficient and are economical so that the charges which are ultimately levied on all electricity customers are justified.

This means SHE Transmission is subject to a funding mechanism established by Parliament and regulated by Ofgem. Cross subsidies between different businesses in the SSE group is not permitted.

How are proposals scrutinised?

The Scottish Ministers are responsible for determination of applications submitted under Section 37 of the Electricity Act 1989. Both statutory consultees and members of the public have the right to submit their representations on the application. All representations will be considered by Scottish Ministers in their determination of the application.
The Office for Gas and Electricity Markets (Ofgem), as the regulator, has to approve all investment so project proposals are developed under license conditions.
Preferred route corridors chosen will comply with revised ‘Holford Rules’ which are the recognised industry approach to routeing overhead lines amended to reflect Scottish circumstances.

How and to what extent are electricity consumers' interests considered?

SHE Transmission are regulated by the Office for Gas and Electricity Markets (Ofgem), the regulator responsible for representing consumers' interests. Electricity consumer interests are therefore one of our key drivers and this is enshrined in our statutory duties under the Electricity Act.

In particular we have a statutory duty to develop, maintain and operate an efficient, economic and co-ordinated transmission system. Since the costs of these projects will ultimately be paid for by electricity consumers, we have a responsibility to take cost into account with due weighting in a comparison against other important factors.

What is the transmission network?

It’s the highest voltage electricity network in the UK – the ‘motorway network’ of the energy world. It transmits large quantities of electricity over long distances via wires carried on a system of mainly metal towers (pylons) and large substations. Transmission voltages in Scotland are 132kV, 275kV and 400kV. Larger generation schemes usually connect to the Transmission system.

The lower voltage parts of the system are called distribution networks. In Scotland, these local networks operate below 132kV whereas in England the distribution network includes 132kV. 

Pre-application consultation events

Great turnout, over 30 members of the public and stakeholders were welcomed at The Cabarfeidh Hotel in Stornoway on Monday to talk to the project team at the pre-application event for the marine cable due to be submitted in April 2018. Further events are being held at: The Argyle Hotel Ullapool - Wednesday 14th March 3pm - 7pm Badcaul Primary School - Thursday 15th March 3pm - 7pm

Pre-application consultation events

Scottish and Southern Electricity Networks (SSEN) is proposing to install a new submarine electricity cable between Stornoway and Dundonnel to enable the connection of renewable energy. The project team will be in attendance for this open door event where members of the community can drop in at any time to receive information and ask any questions on the proposals. The Cabarfeidh Hotel Stornoway Monday 12th March 3pm - 7pm The Argyle Hotel Ullapool Wednesday 14th March 3pm - 7pm Badcaul Primary School Badcaul Thursday 15th March 3pm - 7pm

Consultation on treatment of non-mainland GB onshore wind projects

We have today responded to the UK Government consultation on treatment of non-mainland GB onshore wind projects, to read our response please go to the ‘Project documentation’ section of the project website

Project Tender Update

Scottish Hydro Electric Transmission is currently undertaking a competitive tender exercise for the whole of the project and is working towards identifying a preferred Principal Contractor by the end of March 2017 with the overall project delivery currently anticipated to be by the end of September 2021.

Arnish Booklet

Related Projects: Western Isles

File Type: pdf
Published: 14 Jun 2022


Western Isles - Arnish Consultation Feedback June 2022

Western Isles - Arnish Consultation Feedback June 2022

Feedback form from consultation event in June 2022

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