Project Type: Transmission reinforcement
Location: Highland

Contact Details

Liaison Manager

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

Land Manager

Alastair Macmillan
Title: Wayleaves Officer
Mobile: 07584 313892
Address: 10 Henderson Road, Inverness, IV1 1SN
Status: Early Development

Our proposals

Our proposed Lairg-Loch Buidhe transmission reinforcement comprises of the following elements:

  • New Lairg Substation (Dalchork) Construct a new outdoor 132kV Air Insulated Switchgear (AIS) substation north of Lairg, adjacent to the existing 132kV single circuit overhead line.
  • Lairg to Loch Buidhe Overhead Line Construct approximately 17km of 132kV double circuit overhead line between the proposed new Lairg substation and the Loch Buidhe substation (due for completion in summer 2018) on a new alignment.
  • Lairg to Shin Overhead Line Dismantle approximately 12km of existing 132kV overhead line between the existing Lairg Grid Supply Point (GSP) and the Shin Substation (Inveran)

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.


Seven potential new substation sites were assessed based on existing and future circuits that require to connect into the substation, including wind farm developments.

3 options for the substation site were short-listed – marked as A, C and D.

Site A, adjacent to the existing Lairg GSP, was initially favoured


Initial Overhead Line Route Options

SSEN undertook a detailed assessment to identify a potential OHL route between the proposed new Dalchork Substation and the Loch Buidhe Substation due for completion under a separate project in summer 2018.

The first step of the route selection process identified a number of route options as shown on the figure opposite.

These initial options were presented with Option 2, shown in blue being favoured following initial assessments

Response to initial consultation

  • Feedback from the public following initial November 2013 consultation reflected strong concerns about substation Site A and the overhead line route initially identified
  • Further investigation identified that refinement to substation Site C, moving it further from the roadside, could allow it to be developed with reduced visual impact
  • This refinement to Site C addressed one of the main concerns which had been raised about this option by consultees

Proposed OHL Alignment – June 2014

In light of the changed substation site, the alignment shown was developed, seeking to balance technical, economic and environmental factors as required by SHE Transmission’s licence




Further review of route options

  • Following consultation in June 2014, feedback reflected continuing concerns about the proposed overhead line route, shown in brown
  • Community Action Lairg Loch Buidhe (CALL) asked for an alternative route, shown in blue, to be considered
  • SHE Transmission agreed to carry out a further review of this option in comparison with its proposed alignment

Presentation of conclusions – February 2015

  • Our work reaffirmed a number of significant challenges associated with the alternative route when compared with the route currently proposed, including:
  • ◦the potential for significant adverse impacts on two protected species;
  • ◦challenging access for construction and maintenance; and
  • ◦engineering impacts associated with crossing steep slopes on the route.
  • SHE Transmission is required by its licence to take a balanced decision and, in this case, we believe that means selecting the route corridor that is favoured by most environmental, technical and economic considerations, although we recognise that it is not the preferred option of the local community.
  • These findings were presented via a further public event in Lairg in February 2015

Cable Options

  • 3 potential cable options were identified: A, B and C
  • All cable options require 2 cables per phase (compared with one conductor per phase on an overhead line) due to the rating of the connection required
  • There would, therefore, need to be a total of 12 cables, plus 2 fibre optic cables for communications

The cable options can be split into 2 categories: 2 that seek to follow existing roads (A and C, with a length of 3.3-3.75km); and 1 that goes directly through fields (B, 2.45km


Cable Considerations

  • All options require a Horizontal Directional Drill under the railway line
  • All options require a minimum 40-metre wide construction corridor
  • All options include areas of rock and peat
  • Terminal towers and sealing end compounds would be required at either end of the cable section which presents a localised visual impact
  • Steep inclines introduce design and construction issues with anchoring cables. Trench washout may be a problem.



2017 Review of Background Generation

  • In early 2017 SSEN carried out an internal review of the connected, contracted and scoping wind farm developments in the Lairg area

  • Following the review which included studying the network under various scenarios, the review recommended that the reinforcement option should change from a 275kV to a 132kV OHL solution.


  • Proposal of Application Notice public exhibition (Q2).
  • Production of the Environmental Assessment Reports (Q2).
  • Submit Town & Country Planning Application for the substation.
  • Submit Section 37 (s37) consent application for the OHL (Q2).
  • Statutory consultation as part of consenting process.


  • T&C and s37 Consent Decisions Anticipated (Q2).
  • Award of construction contract.


  • Subject to consent, start of construction.


  • Construction and commissioning completion.
  • Dismantling redundant OHL.

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.

What are The Holford Rules?

The Holford Rules originated in 1959 as the result of work by Lord Holford, a part-time member of the Central Electricity Generating Board (National Grid's predecessor). The Holford Rules have been augmented by both National Grid and SHE Transmission plc to reflect environmental legislation and best practice in recent years. We have continued to use them as a valuable set of guidelines for reducing the impact of our assets on landscapes.
The guidance recommends appropriate application of the Holford Rules to inform routeing. These rules advocate the application of a hierarchical approach to routeing which first avoids major areas of highest amenity, then smaller areas of high amenity, and finally considers factors such as backdrop, woodland and orientation. The Holford Rules apply the term ‘amenity’ to refer to environmental designations and classifications such as Natura 2000 sites, Sites of Special Scientific Interest (SSSI), Scheduled Monuments, Listed Buildings, National Parks.
The guidance also recognises that the key effect of overhead lines is visual and it advises that the routeing of overhead lines should consider the types of mitigation (screening) that could offset any visual effects.
In their National Policy Statement EN-5, the Government has stated that the Holford Rules “should be followed by developers when designing their proposals.” Their use is therefore Government policy, rather than a voluntary choice of SHE Transmission plc.

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. 

Project Update November 2017

Following on from the public meeting attended in February 2017 when we talked about the preferred route there has been a review of the generation background in the Lairg area within Scottish and Southern Electricity Networks. The preferred project reinforcement option to progress changed from a 275kV to a 132kV overhead line circuit and in June 2017 we updated the community and website to reflect this. Over the past ten months, we have been revising the design, and we are now in a position to hold a public consultation event on 6 December 2017 at Lairg Community Centre to share this information and seek feedback on the project. We would encourage members of the community to come along to see the revised alignment and reduction in the tower size and substation footprint and speak to the project team.

Project Update

An internal review of the generation background in the Lairg area within Scottish and Southern Energy Networks has been ongoing. The preferred project reinforcement option to progress has changed from a 275kV to a 132kV overhead line circuit - this change will require a revised design and potential changes tower height, locations and numbers. Once a revised design is available a further public consultation event will be held to share with the community.

Project Update

We can confirm that options to reinforce the network between Lairg and Loch Buidhe remain under review. The review is being undertaken following a change to the amount of generation contracted to be connected to the network. The review will assess the optimum technical solution to deliver the necessary capacity to accommodate the need of all network users .

Lairg Map

At the most recent meeting with Dr Paul Monaghan MP and members of the local community, our project team explained that we are currently carrying out an Environmental Impact Assessment on the proposed transmission reinforcement. This includes continuing consideration of design options which could offer potential to avoid, reduce or mitigate impacts identified – including landscape and visual impacts. As agreed at the meeting, we have published a map showing the latest iteration of the current design proposal, including indicative tower positions. This is not the final design proposal and will be reviewed in light of the findings of our continuing work. Please go to 'Project Documentation' to download.

Public Meeting

A public meeting will take place at Lairg Community Centre on Wed 5 October at 7.00pm, to further discuss the Lairg to Loch Buidhe 275kV overhead line and associated substation with the local community.

Local People

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

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