Frequently asked questions
On this page you’ll find answers to some of the most frequently asked questions about Grimsby to Walpole.
Project Overview
Grimsby to Walpole is a proposal for a new high-voltage overhead electricity transmission line. It will connect a new substation at Grimsby West, called New Grimsby West to a new substation at Walpole, called Walpole B. Between these points will be a number of additional substations, including Lincolnshire Connection Substations A and B near Mablethorpe and up to two substations at Weston, near Spalding.
This Project is a key part of reinforcing the electricity transmission network. It’s designed to support new home-grown power generation and meet the growing demand for electricity.
You can find more details on the Our proposals page.
The electricity transmission system, made up of pylons, overhead lines and underground cables, was mostly built in the 1960s. It wasn’t designed to carry electricity from where it’s increasingly generated today: offshore wind farms and solar panels.
Electricity demand in Britain is expected to at least double by 2050. That means we’ll need to move much more energy to homes, businesses and public services. At the same time, we’re seeing rapid growth in offshore wind, interconnectors and nuclear power. This means more electricity will be generated than the current network can handle securely and reliably.
Grimsby to Walpole is one of five new electricity transmission projects being proposed in Lincolnshire. Three are mainly offshore projects. Grimsby to Walpole is an overhead line project. All are part of The Great Grid Upgrade – the biggest overhaul of the electricity transmission network in Britain for a generation. We require these new reinforcement projects so we can continue to deliver a reliable, affordable network into the future and meet the rising demand for electricity.
Much of the existing network in this area was built in the 1960s to serve coal and gas power stations. Today, the Lincolnshire coast is home to a growing number of renewable energy projects, but the infrastructure hasn’t kept pace. That means we can’t always get this clean, home-grown power to where it’s needed most.
Electricity demand is rising as more people switch to electric vehicles, heat pumps and other low-carbon technologies. At the same time, more renewable energy is being generated, especially along the east coast. To keep up, we need to upgrade the grid so it can carry more electricity and keep supply reliable.
Grimsby to Walpole plays a key role in building a more secure and resilient energy system, one that can reliably move electricity between the North, Midlands and South of England.
This Project will strengthen key parts of the network, especially across boundaries B8 and B9, which need more capacity by 2035. It includes a new 400 kV double circuit to connect offshore wind, solar, energy storage and other low-carbon sources to the grid.
Without these upgrades, the network won’t be able to meet future demand. This work is vital and will also support local jobs, skills and investment.
Progress and Timeline
In Spring 2024, we held our Stage 1 consultation to share early proposals for Grimsby to Walpole. Since then, we’ve carefully reviewed all the feedback we received. We also considered ongoing conversations with stakeholders, technical assessments and environmental surveys. Together, these helped us shape and improve our plans ahead of Stage 2.
Before launching Stage 2, we carried out another review looking closely at where community suggestions could help us refine the route further. This work is part of our preparation to submit a development consent order (DCO) application to the Planning Inspectorate.
You can find more detail on the feedback we received, and how we’ve responded in our 2024 Stage 1 consultation feedback report, available in the Document Library.
We’re currently preparing for our Stage 2 consultation for Grimsby to Walpole. This next stage will give you the chance to explore our updated proposals, ask questions, and share your feedback.
What you tell us during this consultation, alongside ongoing technical and environmental assessments, will help us finalise the plans for the Project.
We’ll include a full account of how we’ve considered all feedback in our Consultation Report. This will form part of our development consent order (DCO) application, which we expect to submit to the Planning Inspectorate soon.
Grimsby to Walpole is progressing through key phases, from early consultation to construction and operation. Here’s an indicative timeline of the main milestones:
- January – March 2024: Stage 1 (non-statutory) consultation
- April 2024 – May 2025: Review of Stage 1 feedback and design refinement
- June – August 2025: Stage 2 (statutory) consultation
- Winter 2025 / Spring 2026: Localised consultation on Weston Marsh substation proposals
- Summer 2027: Submission of the development consent order (DCO) application
- Winter 2027: Examination of the application by the Planning Inspectorate
- 2028: Recommendation and decision by the Secretary of State
- 2029 – 2033: Construction
- 2033: Operation.
Local feedback has played an important role in shaping the Project so far. After the Stage 1 consultation in Spring 2024, we reviewed all the feedback we received and identified areas where design changes could be made. This input, alongside ongoing engagement with stakeholders, technical assessments, and environmental surveys, has helped us develop the proposals for the Grimsby to Walpole Project ahead of Stage 2 consultation.
The Proposals
The aim of Grimsby to Walpole is to strengthen the network, boosting power transportation between the north, the Midlands, and the South, and providing connection points for new renewable generation. Proposing building the Project elsewhere would not increase the capacity where it is needed.
Pylons are still one of the best ways to transport power. They can carry larger volumes of power than underground cables and are more cost-effective and simpler to build and maintain.
Planning policy also states that overhead lines should be the starting position when bringing forward new electricity network developments.
Costs of new electricity infrastructure are ultimately passed onto bill-payers, so we need to ensure that we are being economical and efficient in the transmission options we develop.
The reasons are technological, environmental and the impact to electricity bills. An overhead line can carry significantly more power than underground cables. To deliver Grimsby to Walpole’s 6 GW of power capacity via underground cables, the Project would require three times more cables than overhead line and would therefore need far more land – mostly agricultural land - for construction.
It would require a construction corridor between 40 and 120 metres wide, which would have greater environmental and construction impacts on local farmland and communities, including potential road closures.
During operation, any technical work on underground cables, including repair and replacement, would require excavation works. This would further disrupt local farmland, agricultural practices and communities.
The impacts of maintenance and operation of overhead lines are far less significant. As well as offering environmental and technical advantages, an overhead line is also the most cost effective solution to deliver. Compared to underground and offshore alternatives, which are significantly more expensive and complex to install and maintain, an overhead line helps manage the overall cost of the new infrastructure. This is important because the costs of such projects are ultimately considered by the energy regulator Ofgem when determining the charges paid by everyone in their electricity bills.
We have therefore proposed overhead line because it balances these cost, technical and environmental challenges in order to deliver home-grown, more affordable electricity from Scotland to Lincolnshire, the East Midlands and England.
We must bring forward the right proposals in the right place, working within the policy and regulatory framework set by Government and Ofgem. EGL3, EGL4 and Grimsby to Walpole are each separate projects, needed for different reasons.
Grimsby to Walpole is a 90 mile (140 kilometre) new onshore overhead line, needed to: (i) increase the capability of the network to carry more power to homes and businesses; and (ii) connect new sources of energy that are planned in the area. These include seven solar farms with battery storage, two offshore wind farms, two interconnectors, three gas-fired generation projects with battery storage and a subsea link from Scotland. It will carry enough electricity to power up to six million homes to where it is needed
EGL3 and EGL4 will each bring home-grown energy from different parts of Scotland over much longer distances through offshore subsea cables to the Midlands and South of England. Each will carry enough electricity for up to two million homes.
We are proposing overhead for Grimsby to Walpole as this provides the most cost-effective option for electricity bill payers. It is vitally important we reinforce these parts of the onshore network to carry electricity from new home-produced sources of energy that are planned in the area. Overhead lines are the least environmentally impactful technology we can use whilst transmitting the maximum amount of electricity. The EGL projects on the other hand are much longer distance and lower capacity offshore cables from different parts of Scotland, that are not connecting other sources of energy along the way. Those circumstances lend themselves to cost effectively running the cables via the sea and underground using high voltage direct current cables, to where the electricity is needed.
Grimsby to Walpole will use High Voltage Alternating Current (HVAC). This matches the existing transmission network, so it can connect directly. On the other hand, EGL 3 and EGL 4 will use High Voltage Direct Current (HVDC). HVAC and HVDC are different technologies and you can’t mix these.
Whilst there is the potential in some areas for infrastructure from all three projects to be located in similar areas, there are engineering, planning, environmental and technical factors that mean co-locating the projects along their entire length is not possible.
Additionally, minimum electrical distances need to be maintained between Grimsby to Walpole and both EGL 3 and EGL 4 to ensure the reinforcements work safely and effectively. Each of Grimsby to Walpole’s pylons requires foundations that would prevent any underground cables from being easily accessed for maintenance and repair in the event of a fault.
Infrastructure
Pylons support high-voltage overhead lines, the cables that carry electricity as alternating current across the country. They keep these lines safely elevated over roads, rivers, valleys and railway tracks.
Overhead lines can carry more electricity than underground or subsea cables using a single piece of infrastructure. For example, one line of pylons can transport around 6,930 megawatts (MW), while the largest underground high-voltage direct current (HVDC) system can carry up to 2,000 MW.
Pylon height varies depending on the landscape and local needs. In areas with visual or environmental sensitivities, we may use low-height pylons to help reduce the impact.
Substations house electrical equipment which enables the system operator to control the flow of electricity. These substations come in many sizes and configurations depending on the need. Substations are also key in helping to isolate and fix faults and allow maintenance to be undertaken safely on the electricity network.
Gantries are bridge-like structures that support equipment and cables. They guide power lines from the final pylon into the substation, connecting them to the electrical equipment inside.
Angle pylons, also known as deviation pylons, help carry power lines around bends in their route. They have a distinctive design, with uneven arm lengths and wider bases for extra stability. These features help keep the power lines secure, especially where the route changes direction.
Local impact
We are undertaking a wide range of environmental surveys and assessments to identify potential effects on the environment as well as proposals to mitigate them.
The emerging results of these studies are detailed in the Preliminary environmental information report (PEIR). Feedback on the PEIR will help to inform the Environmental statement (ES) for the development consent order (DCO) application.
We’ve developed a proposed overhead line route and substation sites to minimise impacts on environmentally sensitive areas, including the Lincolnshire Wolds National Landscape.
The Stage 2 consultation seeks feedback on environmental mitigation areas, including those identified for landscape and wildlife mitigation.
For areas where there is an overhead line, it is mostly only the land directly under each pylon that is affected. A single pylon will occupy just a small area of land, so most normal agricultural practices are still viable along the route. For the construction and operation of substations, inevitably there will need to be the purchase of land for their construction and operation. We are working with landowners, including farmers, to mitigate impacts and ensure we understand and address the concerns of individuals and businesses where possible.
We aim to manage impacts on the landscape and views as much as possible, and respect the special characteristics of designated areas like the Lincolnshire Wolds National Landscape (formerly AONB).
The updated proposed route is sensitive to the landscape and proposes low-height pylons between Barnoldby le Beck and Waithe to minimise impacts. We have made routeing adjustments and are also considering natural screening with trees and hedges to minimise visual intrusion.
We welcome feedback on these proposals to ensure we effectively address community concerns and environmental impacts.
The Project includes comprehensive drainage and flood risk management plans to mitigate any potential increase in flooding. We will assess existing drainage systems and prepare pre-and post-construction drainage management plans. These measures ensure that the Project does not exacerbate flood risks and maintains effective drainage for local communities.
We understand how valuable agricultural land is and are committed to minimising our impact.
During construction, topsoil will be carefully removed and stored next to the working area so it can be returned to the same spot. This helps preserve its structure, nutrients, and organic content. All soil handling will be overseen by qualified professionals, and a tailored aftercare plan will support the land’s return to its original condition and grade.
Good drainage is just as important. Before any work begins, a specialist contractor will assess the existing drainage systems in consultation with landowners and stakeholders. We’ll create a pre-construction drainage plan to record the current setup, and a post-construction plan to make sure everything is restored and continues to work well.
These steps are designed to protect the long-term health and productivity of the land.
Yes, we’ve carefully considered the environmental impact of Grimsby to Walpole. We’ve assessed the likely significant effects over the Project’s lifetime and identified ways to avoid, reduce or offset them.
We’ve grouped our mitigation measures into three categories:
- embedded measures: These are built into the project design to reduce environmental effects from the start. For example, we’ve chosen low-height pylons in some areas to help reduce visual and environmental impact
- control and management measures: These reflect our commitment to good practice during construction. They’re set out in documents like the Code of Construction Practice (CoCP) and Construction Traffic Management Plan (CTMP). Examples include screening to reduce noise and using haul roads to keep construction traffic off local roads where possible
- additional mitigation measures: These are extra steps we take when impacts can’t be designed or managed out. For instance, we’ll enhance or create habitats to deliver biodiversity net gain (BNG).
You can find the full list of proposed mitigation measures in our Preliminary Environmental Information Report (PEIR), available in the Document Library.
To support construction of Grimsby to Walpole, a wide range of roads will be used to safely and efficiently move materials, equipment, and personnel:
- wherever possible, construction traffic will use the Strategic Road Network (SRN), including the M180, A180, and A47. These roads are managed by National Highways and are designed to handle higher volumes of heavy vehicles
- in addition to the SRN, several A roads managed by local highway authorities will be used to access construction areas. Routes are selected to avoid travelling through villages where possible and to prioritise roads with suitable width and surface quality to reduce disruption to local communities
- some B, C, and unclassified roads may be used to reach remote or agricultural sites. These roads will be assessed for suitability, and where needed, mitigation measures, such as temporary closures, traffic management, or surface improvements will be considered.
Route selection will continue to be refined as the Project progresses, in close coordination with local highway authorities and stakeholders, to ensure routes remain safe, efficient, and minimise disruption.
We’re committed to working closely with land and property owners as we develop our plans for Grimsby to Walpole. We’ll keep you updated as the Project progresses and encourage you or your professional representative, to get in touch if you have any questions or concerns.
As part of our statutory consultation, we’ve written to all landowners who may be affected by our proposals, sharing details about the Project and how to take part in the consultation.
If you’re a landowner and think your property might be affected, you can contact our Lands team directly:
- email: [email protected]
- phone: 0333 034 7961
- post: Unit 1, Staplehurst Farm, Weston on the Green, OX25 3QU.
Consultation
You can have your say on Grimsby to Walpole by taking part in our Stage 2 consultation, open until 11:59pm on Wednesday 6 August 2025. This is your chance to comment on our updated proposals for new overhead lines and substations that will help support the UK’s move to cleaner energy.
There are several ways to share your feedback:
- online: Fill in the feedback form at nationalgrid.com/g-w
- email: Send your comments to [email protected]
- post: Write to Freepost G TO W (no stamp needed)
- in person: Pick up a printed form at local information points
To find out more, visit the Project website, come to a public information event, or join an online webinar. These sessions are a great way to explore the plans, ask questions and speak with the team. You can also visit local libraries and community hubs along the route to view printed materials and technical documents.
If you have any questions or need help, call us on 0808 258 4395 (Monday to Friday, 9am–5pm). Your feedback will help shape the final proposals before we submit our application for development consent.
Once the Stage 2 consultation for Grimsby to Walpole closes on 6 August 2025, we’ll carefully review all the feedback we receive. This input, alongside ongoing technical and environmental assessments, will help us refine our final proposals.
Here’s what happens next:
- we’ll continue working closely with landowners, local authorities, elected representatives and other stakeholders.
further technical studies and surveys will take place across the Project area. - we’ll develop detailed proposals for the Weston Marsh substation, which will be consulted on at a localised consultation in Spring 2026.
- in Summer 2027, we’ll submit a full application for a development consent order (DCO) to the Planning Inspectorate. This will include a Consultation Report showing how feedback has shaped the final plans.
If the application is accepted, the Planning Inspectorate will examine it and make a recommendation to the Secretary of State for Energy Security and Net Zero, who will decide whether to grant consent.If approved, construction is expected to begin in 2029, with the Project becoming operational by 2033.
About National Grid
National Grid sits at the heart of Britain’s energy system, connecting millions of people and businesses to the energy they use every day. We bring energy to life – in the heat, light and power we bring to our customer’s homes and businesses; in the way that we support our communities and help them to grow; and in the way we show up in the world. It is our vision to be at the heart of a clean, fair and affordable energy future.
Within the National Grid Group there are distinctly separate legal entities, each with their individual responsibilities and roles. More information on National Grid can be found here.
National Grid Electricity Transmission owns, maintains and operates the high voltage electricity transmission network in England and Wales. This network operates primarily at 400 kilovolts (kv) and 275 kV.
National Grid Strategic Infrastructure is developing the proposals for North Humber to High Marnham. The proposals form part of The Great Grid Upgrade, which is the largest overhaul of the electricity grid in generations.