Much of the electricity transmission network in Scotland is between 50 and 100 years old. It has grown and evolved to meet industrial needs and serve the expanding population, but the network in central Scotland is approaching full capacity – while our need for clean, green renewable energy continues to grow.
More onshore and offshore wind farms, solar energy and battery storage sites are connecting to the power network. That means we need to increase the voltage of the overhead transmission lines in this area, in keeping with the wider electricity transmission network, to create more capacity so we can get the energy from where it’s produced to where it’s needed.
Extending Clydesmill substation to accommodate new 400kV transformers and equipment will allow the voltage of a circuit on the existing overhead line between
Clydesmill and Denny North substation to increase from 275kV (275,000 volts) to 400kV.
This will contribute to connecting Clydesmill to the planned new Kincardine North substation – ensuring greater security of electricity supply in future for the surrounding area, including Easterhouse, Clydesmill, East Kilbride and Newarthill.
What will happen at Clydesmill substation?
View a larger version of the site plan.
The proposed extension to the existing Clydesmill 275kV substation will include new equipment and security fencing, earthworks and drainage improvements, vehicle access and parking.
What has changed since our previous consultation?
We considered all feedback received on the early proposals we shared in February 2025, and following further technical and environmental assessments, we have revised our design as follows:
- Red line boundary (the area covered by our planning application) extended to allow for substation platform, access road and drainage solution.
- Number of access roads reduced from two to one.
- Sustainable Drainage System (SuDS) basins redesigned, based on progress in drainage solution design and changes to platform outline and access roads.
- Maintenance trackway added for SuDS pond in east of site.
- Reduction in length of access tracks for SuDS maintenance and welfare compound, near site entrance.
- Platform for 400kV substation extension will now be level with existing platform.
We will need to uprate one of the circuits – the east side – of the existing ZD overhead line between Clydesmill and Denny North substation from 275kV to 400kV to increase network capacity and ensure greater security of supply for the local area in future.
We will need to make changes to two existing overhead lines, where they enter Clydesmill and Denny North substations. At Clydesmill we will need to install one new tower and a section of overhead line to the north of the site, to replace one tower and a short section of overhead line. South of the site we will need to install one new tower and remove two existing towers.
The works at Denny North substation will include two new towers and two new spans of overhead line.
View the interactive map below shows the proposed changes at Clydesmill.
Who are SP Energy Networks?
SP Energy Networks is part of the ScottishPower Group. We are responsible for the transmission and distribution of electricity in central and southern Scotland, and, through SP Manweb, the distribution network in North Wales and part of North West England. Our role is to maintain, operate and invest in our network to secure a safe, reliable, and economic service for current and future consumers.
What statutory obligations does SP Energy Networks have?
Our statutory obligations are set out in the Electricity Act 1989 and in our transmission licence. We must develop and maintain an efficient, coordinated and economical transmission system in accordance with security and quality of supply standards. We must offer to connect new power generators to the system and, make sure any work we do keeps disturbance to the natural and built environment and the people who live in it, work in it or enjoy it to a minimum.
Who regulates SP Energy Networks?
We are regulated by Ofgem (Office of the Gas and Electricity Markets), and independent national regulatory body. Further information about Ofgem is available on:
Why is the Clydesmill Substation Extension and Overhead Line Uprating needed?
Much of the electricity transmission network in Scotland is between 50 and 100 years old. It has grown and evolved to meet industrial needs and serve the expanding population, but the network in central Scotland will soon be at full capacity – unable to accommodate all the clean, green renewable energy we will all need in future.
We need to increase the voltage of the overhead lines in this area from 275kV to 400kV so we can get more energy from where it’s produced to where it’s needed.
The proposed new substation extension at Clydesmill and associated overhead line uprating will have a key role in enabling Scotland and the UK to meet Net Zero emissions targets while ensuring that power flows efficiently through the system in central Scotland. It will also strengthen the regional power network so it can cope with any unexpected faults in future.
What exactly are you proposing?
The Clydesmill Subsation extension project will involve a range of new infrastructure including:
- 2 x 400/275kV 1000 MVA inter-bus transformers
- 2 x 400kV air-insulated switchgear circuit breakers
- 1 x 400kV bus section circuit breaker
- Air-insulated switchgear and busbar connections
- Gas insulated busbar connections (non SF6)
- Modular Control Building
- Vehicle access and parking
- Earthworks and drainage improvements
- A new 3m high, steel palisade fence and internal fencing around the live compound to ensure safety and security.
- We will need to uprate one of the circuits – the east side – of the existing ZD overhead line between Cydesmill and Denny North substation from 275kV to 400kV to increase network capacity and ensure greater security of supply for the local area in future.
We will need to make changes to two existing overhead lines, where they enter Clydesmill and Denny North substations. At Clydesmill we will need to install one new tower and a section of overhead line to the north of the site, to replace one tower and a short section of overhead line. South of the site we will need to install one new tower and remove two existing towers.
The works at Denny North substation will include two new towers and two new spans of overhead line.
How much will the project cost?
It is early days and we won’t be able to cost the project fully until we have a definite proposal.
Who will pay for this project?
Ultimately, the cost of our investment in the electricity system is partly borne by consumers through electricity bills, so we are obliged to be economic and efficient. We recover our costs through transmission charges levied by National Grid.
The amount we invest in our networks and the amount we are able to recover is agreed with Ofgem, which is committed to working with industry, governments and consumer groups to deliver a net zero economy at the lowest cost to consumers. You can find out more about Ofgem.
How are you consulting local people?
We consulted local people and other stakeholders in February 2025 on our initial plans to extend Clydesmill substation and upgrade the overhead line (ZD route).
We considered all comments received, and following further technical and environmental assessments we have revised our plans. We are consulting local people and stakeholders on these updated plans during February 2026, and we will provide further feedback in March 2026 before we submit our planning and consent applications.
There will be further opportunities for local people and other stakeholders to comment on the plans after our applications have been submitted.
Are you consulting landowners?
Yes, we will be talking to owners and occupiers of land that might be affected by our proposals. If you believe that your land may be affected and you have not yet heard from us, please contact us on our Have Your Say tab.
Can you tell me more about Electric and Magnetic Fields (EMFs)?
Wherever electricity is used there will also be electric and magnetic fields. This is inherent in the laws of physics – we can modify the fields to some extent, but if we are going to use electricity, then EMFs are inevitable.
Like many other things that we encounter in nature, EMFs can be harmful at high-enough levels. But the fields required, for example, to start interfering with the body’s nervous system are much greater than those produced by the UK electricity system. Hundreds of millions of pounds have been spent investigating this issue around the world. Research still continues to seek greater clarity; however, the balance of scientific evidence to date suggests that EMFs do not cause disease.
For more information, please see the EMF - The Facts
We are holding a public consultation on our plans from Monday 9th February to Friday 27th February 2026. An online feedback form will be available here between those dates for you to give us your comments.
Local residents are invited to our public exhibitions where you can see our plans in more detail, meet the project team and ask any questions you may have:
Wednesday 11 February, 10am to 2pm: Halfway Hall, 26 Graham Avenue, Cambuslang, Glasgow G72 7RB
Friday 13 February, 2pm to 7pm: Cambuslang Institute, 37 Greenlees Rd, Cambuslang, Glasgow, G72 8JE
If you have any questions regarding our proposals, please contact us at clydesmill@communityrelations.co.uk or by calling 0800 470 2376.
At this stage, your comments are not representations to the planning authorities. It is when we submit applications for development consent in the future that you will be able to make formal representations to those planning authorities.
What happens next?
Following the February 2026 consultation, we will finalise our design for the substation layout, including proposed locations for buildings, equipment, internal access routes, landscaping and drainage.
We will be hosting additional events to present our detailed plans and explain how we have considered any feedback received. Details of those events are as follows:
Wednesday 18 March, 10am to 2pm: Halfway Hall, 26 Graham Avenue, Cambuslang, Glasgow G72 7RB
Friday 20 March, 2pm to 7pm: Cambuslang Institute, 37 Greenlees Rd, Cambuslang, Glasgow, G72 8JE
We plan to submit a planning application under the Town and Country Planning (Scotland) Act 1997 (as amended) to South Lanarkshire Council in 2026. We will also submit an application to the Scottish Government Energy Consents Unit, under Section 37 of the Electricity Act 1989, for the proposed changes to the overhead lines and uprating in voltage.