Upcoming piling work at Waltham Cross Substation
The first phase of piling work at Waltham Cross Substation will begin on Monday 6 July 2026 and last around one month.
Piling is a building method used to create strong foundations for large structures like converter stations and substations. It involves driving long steel or concrete piles deep into the ground which provide stability and support for heavy equipment and buildings.
For our first phase of work, we will temporarily use rigs to install pre-cast concrete piles deep into the ground. This will help ensure the upgraded Waltham Cross Substation is built on stable ground.
Later in the construction programme, we will need to carry out three more phases of piling work. We will update this webpage when timings are confirmed.
What to expect
Piling can sometimes be one of the noisier parts of construction, so you may notice some noise and vibration while this work is taking place. Based on our current plans, we expect any impacts to be minimal because the work will take place inside the site compound. To help keep disruption to a minimum, we will monitor noise levels and take steps where needed to reduce any impacts.
We don’t anticipate any additional impact on local roads or traffic because of this work, so our traffic management plans will remain the same.
Waltham Cross is a critical hub for the NLR project, supporting major infrastructure upgrades to strengthen electricity transmission into London. These upgrades are a key part of modernising the electricity network to support the Waltham Cross substation to operate at a higher voltage, enhancing network stability and future proofing the infrastructure to accommodate for our growing energy needs.
We are upgrading the Waltham Cross substation in Lee Valley Park to increase its electricity transmission capacity. The works will see transformers and electrical equipment replaced with higher capacity units, enabling the system to operate at increased voltage levels.
This work involves building an extension to the Waltham Cross substation and constructing a building to house the two new Super Grid Transformers (SGTs) we will be replacing the two existing transformers with.
We’ll also be upgrading the existing overhead line with higher voltage conductors. In addition, we will replace or remove several overhead line towers within Lee Valley Regional Park to accommodate this upgraded line.
We are working with the Lee Valley Regional Park Authority to minimise impacts on park users and protect the local environment during construction.
Please contact us using the details below if you have any questions or would like more information on our work at Waltham Cross.
To find out more about community benefits, please visit our home page.
Construction activity within Lee Valley Park
Construction of the haul road, site access and site compound began in spring 2026 and are expected to continue until works are complete.
As confirmed by the local planning authority, our permitted working hours at Waltham Cross Substation have been extended. To support the timely delivery of the project, construction activities can now take place between 7:30am to 6:30pm, Monday to Friday, and 7:30am to 4:30pm on weekends.
To facilitate our work, we have set up key operational zones for construction activity within Lee Valley Park. These have been established in the former Cornmill Meadows Car Park, and the Fisher’s Green Car Park. As a result, please note that there are a reduced number of parking spots in both car parks.
The surrounding areas will see increased levels of construction traffic and contractor presence as we prepare for the main construction works. Preparation works include installing new access roads and welfare facilities and making upgrades to fencing and security systems to ensure site safety.
Construction traffic
We are working closely with the local authority and have developed comprehensive management plans to manage increased traffic in Lee Valley Regional Park. Our plans are designed to minimise impacts on park visitors and local traffic as much as possible.
National Grid employees and contractors will access the site in construction vehicles via Holyfield Road and Stubbins Hall Lane. We are also setting up a temporary haul road on the east side of the site, to facilitate safe vehicle movements.
Five-way traffic lights will be in place to ensure the safe movement of construction vehicles, park visitors and pedestrians. The traffic management is expected to remain in place for at least two years while deliveries are ongoing. During peak activity, there will be a maximum of 30 Heavy Goods Vehicles (HGVs) deliveries per day, although traffic levels will vary depending on the stage of works.
All construction vehicles within the park area will operate within the 10-mph speed limit, with marshalling points established at the top of the access road to control site movements.
Keeping communities informed
We aim to minimise the impact of our project as much as possible and to keep people informed about the work we’re doing at Waltham Cross.
We have started to hold Community Liaison Group (CLG) meetings with key stakeholders to make sure we’re doing what we can to reduce disruption. Our first meeting was on Tuesday 17 March 2026, and you can view the slide deck we presented by clicking here.
We note that works are still being scheduled in this area, and the programme and details of our activities are subject to change.
Register your details with us here to receive information as it becomes available. You can also follow our WhatsApp channel for real-time updates on our activity. Read our Frequently Asked Questions document, including the QR code you can scan to join.
Community fund
We are developing a community fund to recognise and reward the communities near the project. Before it is launched, we are working with local groups, community organisations and key stakeholders to help us understand local needs, priorities and long-term aspirations.
Our first workshop for Waltham Cross was held on 30 April 2026. Thank you to all who attended. You can view the presentation slides we used here.
Works at Waltham Cross
About the works
We are upgrading Waltham Cross Substation as part of our North London Reinforcement project.
This includes extending the substation in Lee Valley Regional Park and replacing equipment so that the network can carry more electricity.
We’re also upgrading the overhead power lines connected to the substation. This includes removing one pylon and replacing several overhead lines within Lee Valley Regional Park.
This work is part of The Great Grid Upgrade, the largest overhaul of Britain's electricity network in generations.
As the UK moves towards cleaner energy and uses more electricity for heating and transport, demand is expected to increase significantly. Existing equipment wasn’t designed to carry the amount of electricity we need to meet this growing demand.
Waltham Cross Substation has been in service for more than 60 years. Upgrading the network, including Waltham Cross will help make sure we can continue to support homes and businesses across North London and the surrounding area.
Safety
Keeping the public safe is our top priority. We have put several measures in place to protect park visitors, cyclists and residents during construction, including:
- clearly marked construction zones with secure fencing to keep the public away from active work areas.
- signs throughout the park to direct people safely around any restricted areas.
- pedestrian routes will be kept safe and maintained at all times, with temporary paths provided where needed.
- a dedicated officer responsible for coordinating all vehicle movements on site
- a 10 mph speed limit for all construction vehicles within the park, enforced by signs and speed-activated displays.
- a booking system for large vehicle deliveries so they arrive at staggered times and do not cause queuing.
- large vehicles are required to drive in and out of the site facing forward, with trained safety staff supervising any reversing near public areas.
- regular checks to make sure all fencing, signs and safety measures are in place and up to date.
We also work closely with the local council and Lee Valley Regional Park Authority so we can respond quickly if any issues arise.
Traffic management
Construction vehicles will access the substation via Holyfield Road and Stubbins Hall Lane. We have also set up a dedicated logistics area on Stubbins Hall Lane to help manage deliveries and reduce disruption.
Temporary traffic lights are in place at the junction off Holyfield Road to help vehicles enter and leave the site safely. We also schedule deliveries to avoid the busiest times of day wherever possible.
All contractors must follow the agreed access routes. Drivers are fully briefed before they begin working on the project.
There will be up to 30 large vehicle movements a day. Deliveries are staggered through the day to reduce the risk of traffic building up on local roads or in the park.
We understand that construction traffic can affect local roads. Before and after major phases of work, we check the condition of the roads our vehicles use.
If our work causes damage to the road surface, we will work with the relevant authority to arrange repairs. During construction, we will also:
- regularly inspect access routes and promptly fix any potholes or damage.
- use wheel-cleaning equipment and road sweepers to stop mud and debris spreading onto public roads.
- adjust road features like speed cushions where needed to protect surfaces while keeping safety measures in place.
Once the major construction work is finished, we will carry out a final check of all the roads we have used.
Access
We will do everything we can to keep paths in Lee Valley Park open. At times, some footpaths and cycle routes may need to close temporarily so we can carry out work safely. If this happens, we will clearly signpost temporary diversions.
For the latest information on any path closures or diversions, please click here to visit our dedicated traffic management webpage.
We will put up signs wherever restrictions are in place and show alternative routes where needed. We will also aim to give advance notice of planned closures, including how long they are expected to last.
We also have a dedicated WhatsApp channel where we share key updates with local communities, including traffic management and changes to working hours.
If you have a question or concern about work in your area, please get in touch with us directly. You can contact the project team at [email protected].
Noise
Some construction noise is unavoidable, but we will do all we can to keep it to a minimum. This includes using modern, well-maintained equipment, turning off engines when machinery is not in use, and monitoring noise levels during the busiest phases of work.
We plan our work carefully to reduce both the length of time and the impact of noisy activity. Standard working hours are 7:30am to 6:30pm, Monday to Friday, and 7:30am to 4:30pm at weekends. We will not work on public holidays. If work is needed outside these hours, we will discuss this with the local council and make sure it is clearly communicated.
Environment
We are committed to protecting wildlife and improving the natural environment where we can. We have set a minimum target of 10% Biodiversity Net Gain on all construction projects. This means leaving the natural environment in a measurably better state than before the work began.
For the North London Reinforcement project, we are currently aiming to achieve 15% Biodiversity Net Gain. At Waltham Cross, we are working closely with Lee Valley Regional Park and specialist ecologists to make sure our work meets environmental requirements.
Before work began, we carried out detailed surveys to identify protected species, important habitats and sensitive areas. We then put measures in place to help protect the local environment during construction.
During construction, we have:
- put additional protection in place around areas close to the River Lea
- appointed specialist ecologists to oversee the works and make sure all wildlife protections are followed
- installed secure fencing around the construction area to prevent any accidental disturbance to nearby woodland, riverbanks and wetland habitats
We will share more detail on habitat improvements and environmental commitments for this area as local plans are finalised.
Stay informed and contact us
If you have a question or concern about our work at Waltham Cross, our Community Relations team is happy to help. You can get in touch with us directly via the contact details below:
Email: [email protected]
Phone: 0800 538 5398
Freepost: FREEPOST NATIONAL GRID NLR
Contact us
If you would like any further information or to speak to a member of the community relations team about the works, please use the contact form on our website or via the contact details below.
Email: [email protected]
Phone: 0800 538 5398