The Proposal
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.
More onshore and offshore wind farms, solar energy and battery storage are connecting to the power network, and we need to increase the voltage of the overhead transmission lines in this area from 275kV to 400kV, 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 to 400kV.
This will contribute to connecting Clydesmill to the planned new Kincardine North substation to ensure greater security of electricity supply in the future for the surrounding area, including Easterhouse, Clydesmill, and Newarthill.
The Clydesmill substation extension will have space for equipment to facilitate new connections that may be needed in future.
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:
- 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
- 1 x 400/275kV 500 MVA autotransformer
- 1 x 400kV disconnector
- 1 x 275kV circuit breaker and associated disconnector
- 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.
- Two 400/275kV Transformers, two shunt reactors and two containerised Automatic Voltage Regulators
Overhead line changes
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.
FAQ's
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
- 1 x 400/275kV 500 MVA autotransformer
- 1 x 400kV disconnector
- 1 x 275kV circuit breaker and associated disconnector
- 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 are planning two rounds of public consultation before we submit our planning application to South Lanarkshire Council.
Our first round of consultation runs until 28 February 2025.
We are holding a public event on Friday 7 February from 2pm to 7pm at the Cambuslang Institute, 37 Greenless Road, Cambuslang, Glasgow, G72 8JE
You can find more details and an online feedback form on our Have Your Say tab.
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.
Have your say
Our public consultation runs until Friday 28 February 2025.
SPEN attaches great importance to the effect our work may have on the environment and local communities. We want to hear what local people think about our plans, to help us develop the project in the best way.
Feedback form
How to contact us
Email: clydesmill@communityrelations.co.uk
Freephone:0800 470 2376
You can write to us free of charge at FREEPOST SPEN DWUP
What happens next?
Following this round of consultation we will develop a detailed design for the substation layout, including proposed locations for buildings, access route and working areas.
We will publish a report summarising the feedback received and how this has influenced our proposals.
We will carry out a detailed Environmental Impact Assessment (EIA), and hold further consultation, before we finalise our proposals and submit a planning application under the Town and Country planning (Scotland) Act 1997 (as amended) to South Lanarkshire Council.
We will agree a Traffic Management Plan with the local authorities regarding vehicle movements and road improvements.
We will also need to submit applications 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.
At this stage, your comments are not representations to consenting authorities. When we submit applications for development consent in the future, you will be able to make formal representations at that stage.