Our proposals
Between 11 June and 6 August 2025, we are seeking your feedback on our updated proposals for reinforcing the transmission network between Grimsby and Walpole.
Our proposals for Grimsby to Walpole include:
- approximately 140 km of new 400 kV overhead transmission line
- a new 400 kV substation to be built in the vicinity of the existing Grimsby West 400 kV Substation in North East Lincolnshire (to be referred to as New Grimsby West Substation). The existing substation would be decommissioned, in full, or part. The extent of decommissioning will be determined and reported in the Environmental statement
- two new 400 kV Lincolnshire Connection substations located south-west of Mablethorpe in East Lindsey (to be referred to as Lincolnshire Connection Substation A and Lincolnshire Connection Substation B)
- up to two new 400 kV substations in the vicinity of the Spalding Tee-Point in South Holland District (to be referred to as Weston Marsh Substation A and Weston Marsh Substation B)
- a new 400 kV substation in proximity to the existing Walpole Substation west of the village of Walpole St Andrew and north of the town of Wisbech, in King’s Lynn and West Norfolk District (to be referred to as “Walpole B Substation”)
- replacement of short sections of existing 400 kV overhead line and local changes to the lower voltage distribution networks to facilitate the construction of the new overhead line and substations.
The Project will include other required works such as diversions for existing overhead lines, temporary access roads, highway improvements, work compounds, and ancillary works. It will also include utility diversions and drainage works. Land would also be required for mitigation and enhancement of the environment, to deliver an overall biodiversity net gain (BNG). BNG is an approach to development that leaves habitats in a better state than before.
We will carry out an Environmental impact assessment (EIA) and submit a full Environmental statement and non-technical summary as part of our application for development consent.
You can view the proposals on our interactive map. To learn more about the detail of what is proposed in your area, please see the ‘Our proposals’ chapter of the Stage 2 consultation document, which is available to download from the Document library.
Route Sections
You can use the Interactive map to zoom in and explore the route and associated infrastructure.
Our proposals for Grimsby to Walpole have been divided into the following Route Sections:
Learn more
Explore our interactive map and photomontages of the proposals.
The new Grimsby West Substation would be located immediately to the west of the existing National Grid Electricity Transmission substation, to the west of Wybers Wood. Once Grimsby West Substation has been constructed, the existing substation would be mostly, or entirely, decommissioned. The new substation would use Air Insulated Switchgear (AIS), meaning most of the equipment would be outdoors.
Click here to look at the detailed maps and plans, or watch the Route fly through videos below.
From the proposed new Grimsby West Substation, the route would cross the A46 between Laceby and Laceby Acres, pass between Barnoldby le Beck and Waltham, then run south towards Brigsley. It would then continue southeast, crossing the B1201 east of North Thoresby, and route west of Fulstow, Covenham St Bartholomew, Covenham St Mary, Yarburgh, and Alvingham, before crossing the Louth Canal east of Louth. The route then heads south, connecting to Lincolnshire Connection Substation-A.
Click here to look at the detailed maps and plans, or watch the Route fly through videos below.
Lincolnshire Connection Substation A is proposed to be located northwest of Alford, to the immediate east of Greenfield Wood and Mother Wood. Lincolnshire Connection Substation B is proposed to be located northeast of Bilsby. The two proposed 400 kV substations would be connected by an overhead line that routes southeast from Lincolnshire Connection Substation A and crosses the A1104 south of Saleby, before crossing the A1111 and connecting into Lincolnshire Connection Substation B.
Click here to look at the detailed maps and plans, or watch the Route fly through videos below.
From Lincolnshire Connection Substation B, northeast of Bilsby, the proposed overhead line would run south over the B1449, pass west of Cumberworth, and cross Sloothby High Lane east of Sloothby. It would then continue south towards the A158 Skegness Road, then west of Burgh le Marsh, crossing the Poacher railway line and Steeping River, before heading southwest past Midville, Gipsey Bridge, and Frithville, crossing the A16 to reach the Refined Weston Marsh Substation Siting Zone.
Click here to look at the detailed maps and plans, or watch the Route fly through videos below.
Up to two new 400 kV substations are proposed in the vicinity of Spalding Tee-Point in South Holland district (referred to as Weston Marsh Substation A and Weston Marsh Substation B). The proposals for Weston Marsh are currently at an early stage, and we are seeking feedback to help shape the design.
A further consultation, providing more developed proposals and seeking your feedback, is planned to be held in Spring 2026 on this section of the Project.
The proposed overhead line would head south from Weston Marsh, crossing the A151 west of Weston, then east, passing north of Weston Hills and Austendike. From Whaplode Fen, it routes southeast, passing north of Whaplode St Catherine and northeast of Holbeach St Johns, then southeast of Tydd St Giles and Newton-in-the-Isle. It would cross the River Nene before continuing east to connect to the new Walpole B substation, north of Walton Highway.
Click here to look at the detailed maps and plans, or watch the Route fly through videos below.
The proposed location for the substation would be to the north of Walton and immediately west of West Drove North, adjacent to the existing 400 kV overhead line. The substation would require us to reconfigure the existing overhead lines that currently connect to the existing 400 kV substation, enabling them to connect into the new substation.
Click here to look at the detailed maps and plans, or watch the Route fly through videos below.
For more information
Visit our Have your say page for a series of in-person events and webinars where you can learn more about our plans from members of our team.