About the project
We are modernising substations that have been in use for over 60 years and doubling the capacity of existing overhead lines between Pelham and Hackney.
This will allow more home-grown electricity, including cleaner and more affordable sources, to flow through the network, strengthening energy security and supporting growing demand.
This project is part of The Great Grid Upgrade – the largest overhaul of the electricity grid 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.
To make sure everyone has access to secure, cleaner and more affordable home-grown energy, we must build new projects as well as upgrade the infrastructure we already have.
Projects like NLR focus on reinforcing the existing network, allowing more energy to flow through the system and supporting the UK’s transition to a cleaner and more secure energy future. The project will support growing demand for power across North London and surrounding areas.
Construction
We will be increasing the capacity of existing equipment between Pelham and Hackney so the electricity system can run at higher voltage and move more power across the network.
As part of this, some substations will be extended, and new technology – such as quad boosters and Supergrid Transformers – will be installed. Overhead lines will be replaced with new, higher capacity cables, known as higher-voltage conductors. Some existing overhead lines will be moved underground, and we will install equipment to connect them into the substations. This is known as a sealing end compound.
We are not building new overhead lines or pylons along the route. Our work focuses on upgrading the existing equipment so it can carry more electricity.
By modernising and replacing equipment in this way, we will increase capacity while making best use of the infrastructure already in place. This upgrade to the existing electricity network will help deliver a more affordable, secure and cleaner energy future, with less disruption for local communities than installing new equipment.
For more information about works in your local area, please visit the In your area page on our website or contact us at [email protected].
Project timeline
NLR will be delivered in stages along the route up to 2030, with work happening at separate locations at various times.
The first phase involves setting up sites, establishing compounds, and creating safe access for vehicles, equipment, and our teams. Preparatory works such as vegetation clearance and delivery of works cabins have already taken place at locations along the route.
The second phase is our main construction works, which involve the upgrade of overhead lines and substations along the route, including the delivery and installation of major pieces of electrical infrastructure such as supergrid transformers and quad boosters.
Once works are complete at each location, we will move over to our third phase, which will see temporary working areas removed and land reinstated in line with agreed plans.
Work timings will vary along the route, as they depend on factors such as equipment deliveries and how works are sequenced across different sites.
The project was granted development consent in 2014, meaning the overall approach to delivering the works - including how construction impacts will be managed - has already been approved.
We will keep communities informed as works progress. For more information about activity in your local area, visit the In your area page on our website or email [email protected].
NLR is a large project across North London, Hertfordshire and Essex, so we are delivering it in stages to keep work safe, efficient and minimise disruption.
Some work has to happen first, such as preparing sites, setting up access and getting areas ready — before construction can begin. At substations, existing equipment may also need to be modified or removed before installation.
Work is carefully planned across all locations. This depends on when major equipment is delivered, how sites connect to each other, and the need to keep electricity supplies running throughout.
By phasing the work, we can manage impacts across the route and make sure each stage is completed safely before the next begins.
We will keep communities informed as works progress. For more information about activity in your local area, visit the In your area page on our website or email [email protected].
Infrastructure
A substation is a site filled with electrical equipment that helps move electricity safely and reliably. Inside, you will find transformers, cables, switches, and control systems.
Electricity leaves power stations at extremely high voltage, which is too strong for homes and businesses to use safely. Substations reduce that voltage and send electricity along local lines into neighbourhoods — powering our homes, workplaces and public buildings.
There are six substations along the NLR route: Pelham, Rye House, Waltham Cross, Brimsdown, Tottenham and Hackney.
An overhead line is a set of electricity wires carried above ground on pylons. These lines form part of the national transmission network, moving large amounts of electricity across long distances, from where it is generated to where it is needed.
The wires on an overhead line that carry the electricity are called conductors. These are strung between pylons and held in place by insulators, which keep them secure and prevent electricity from escaping. You may also hear the word "cable" used to describe electricity wires, but this more commonly refers to insulated wiring used underground or in situations where extra protection is needed, it is different from an overhead conductor.
As part of NLR, we are replacing some existing conductors with new, higher capacity ones, a process known as reconductoring. This allows the lines to carry more electricity without needing to build entirely new infrastructure across London and the surrounding region.
A Supergrid Transformer (SGT) is a large piece of electrical equipment found inside a substation. While a substation is the overall facility that manages the flow of electricity through the network, an SGT is one of the key components within it that does the voltage conversion itself.
It works by taking electricity at the very high voltages used to transmit power across long distances, in NLR's case, 400kV, and stepping it down to a lower voltage that can be distributed to homes, businesses and public services via the local network.
SGTs are among the largest and most complex pieces of equipment in the electricity network. They are substantial in size and weight, which means their delivery to site requires careful planning and coordination with local authorities to manage the impact on local roads.
As part of the North London Reinforcement Project, new supergrid transformers are being installed at Waltham Cross, Hackney, and Brimsdown substations.
A quad booster is a specialised piece of electrical equipment installed within a substation. While an SGT changes the voltage of electricity moving through the network, a quad booster controls and balances the flow of electricity across the network itself.
When electricity demand is high, or when power is flowing unevenly across different lines, a quad booster can redirect electricity from busier lines to those with spare capacity. This helps prevent overloading, improves efficiency and ensures electricity reaches where it is needed reliably.
Like supergrid transformers, quad boosters are large and complex pieces of infrastructure. Their delivery to site requires careful planning and coordination with local authorities to minimise the impact on local roads and communities.
As part of the North London Reinforcement Project, new quad boosters are being installed at Pelham substation.
A sealing end compound is a small, secure site where overhead power lines meet underground cables or connect into a substation. It’s a connection point and safety enclosure that helps different parts of the electricity network work together reliably. They are used at the interface between overhead lines and underground cables.
Inside the compound are cable sealing ends, which are designed to join and seal the cables so they can operate safely at high voltage. These compounds make it possible for electricity to move between overhead lines and underground sections, or into substations, without interruption.
Working with communities
Biodiversity net gain (BNG) means leaving the natural environment in a measurably better condition after development than it was before. It is now a legal requirement for major infrastructure projects in England, and it is a commitment National Grid takes seriously across all of its construction work.
As part of its five-year Environmental Action Plan, National Grid has committed to delivering at least 10% net gain in environmental value, including biodiversity, across its construction projects. For NLR, we’re going beyond the minimum requirement, targeting a 15% biodiversity net gain.
In practice, this means that where works affect land or habitats along the route, we will look to reduce impacts as far as possible and identify opportunities to create or enhance habitats, both on and off site. Any biodiversity gains must be secured for a minimum of 30 years, ensuring that improvements deliver lasting benefits for local nature rather than short-term fixes.
We work closely with Natural England, local authorities and specialist ecologists to identify the right environmental measures for each location. Further details about specific habitat improvements and environmental commitments along the route will be shared as local plans are developed and finalised.
The Community Fund is a funding programme designed to deliver lasting benefits for communities living and working along the NLR route. It reflects National Grid's commitment to leaving a positive legacy in areas that host electricity transmission infrastructure, not just completing the construction and moving on.
We are still developing the fund and want it to reflect what matters most locally. It could support things like skills and training, green spaces, health and wellbeing, and improvements to community facilities.
We are speaking with residents, community groups and local organisations to help shape the fund.
We expect more than £3.5 million to be available across the NLR project route. National Grid is developing the fund in line with Government guidance on community funds for new transmission infrastructure projects, which ensures the programme is structured fairly and that funding reaches the communities that need it most.
We will share more information, including funding arrangements, eligibility criteria and how to apply, once these have been confirmed.
If you have ideas about what the fund should support in your area, or would like to register your interest, please contact us at [email protected].
In addition to the proposed Community Fund, we are also offering a range of wider community benefits as part of the NLR project. This includes delivering social value initiatives. These are the broader, longer-term benefits a project can bring to people, places and communities.
This includes running talks and workshops with local schools about science, engineering and future careers. We also promote local job and skills opportunities, and support charities and community projects through staff volunteering.
Environmental volunteering is another crucial part of this work – we’ve taken part in local clean-ups and worked to improve wildlife habitats. These activities help us to make a positive difference in the areas impacted by our work, during construction and beyond.
We know that construction can affect local communities. Alongside developing our social value commitments, our focus is on keeping people informed, listening to concerns and working closely with local stakeholders. This includes engagement with local authorities, councillors, community groups and affected residents.
You can read more about our social value work, including examples of our ongoing community-focused activity, on our latest news page.
Yes. Substations are designed and operated to be safe for people living and working nearby.
Electrical equipment, including substations and overhead lines, produces electric and magnetic fields (often referred to as EMFs). All substations are designed to operate well within the safety guidelines for EMFs. Due to how the equipment is designed, substations do not produce significant electric fields outside their boundaries, and the magnetic fields they generate reduce quickly with distance.
These guidelines are set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and are adopted by the UK Government. They are based ondecades of scientific research, which has found no consistent evidence of health risks at levels below these limits.
We understand that people may have concerns, and we take them seriously. Our priority is to ensure the safety of the public, our contractors and employees, and local communities, while providing clear and accessible information.
Find out more about EMFs and substations here.
Community engagement
Keeping communities informed and listening to local concerns is central to how we deliver the North London Reinforcement project. We recognise that living or working near construction can raise questions and concerns, and we are committed to being open, accessible and responsive throughout.
We engage at several levels, working with local authorities, elected councillors and parish councils, as well as community groups, residents' associations and directly affected residents. This helps us both share information and understand local views.
As part of this, we run Community Liaison Group (CLG) meetings along the route, bringing together local representatives and the project team to provide updates, discuss upcoming works, and address questions and concerns.
The project was approved by the Secretary of State in May 2014 following public consultation. With construction now underway, our focus is on keeping people informed about what is happening, when and why, and how impacts are being managed.
We have set up a dedicated WhatsApp channel to provide key updates to communities directly. This includes things like traffic management measures, or changes in working times.
If you have a question or concern about works in your area, we would encourage you to get in touch directly. You can contact the project team at [email protected].
The NLR WhatsApp channel is a quick and easy way to stay up to date. We use it to share real-time updates about works in your area, so you can stay informed without having to search for information.
Updates shared through the channel may include advance notice of upcoming works, traffic diversions or road changes, or any unplanned incidents or changes to the programme. We may also share photos and videos to give a clearer picture of what is happening on the ground.
The channel is one-way, meaning National Grid can post updates but followers cannot reply directly through it.
Read our Frequently Asked Questions document, which includes instructions on how to join.
Community Liaison Groups (CLGs) are a way for the NLR project team to engage directly with local representatives and key stakeholders throughout construction.
Each CLG brings together a focused group of invited participants, which may include local councillors, parish council representatives, community group leads and other stakeholders with a direct interest in the project. This allows for open and informed discussion in a setting where local knowledge and concerns can be properly heard and considered.
The best place to find local information about the North London Reinforcement Project is the In your area section of the NLR website.
This part of the site is organised by location, with dedicated pages for each substation and the overhead line route. Each page sets out what works are taking place, where and when activity is happening, and what you might notice locally – such as traffic management or access changes.
Because construction details vary by location, these pages are the best source of information relevant to your area. We update these pages regularly as works progress, so it is worth checking regularly to see when activity is planned in your area.
For broader project information, the NLR website also includes pages covering traffic management, latest project news and FAQs.
If you cannot find what you are looking for, or have a specific question about works near you, please contact the Community Relations Team at [email protected]. We are always happy to help.
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
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