Avonmouth
Current construction activity
| Date from | Date to | Activity |
| May 2021 | 2024 | Building and energising new pylons |
| 2020 | 2024 | Removing existing pylons |
| 2018 | Ongoing | Roadworks and traffic management |
| 2018 | Ongoing | Access to public footpaths and rights of way |
Overview – Spring 2024
National Grid is in the final stages of completing the north section of the Hinkley Connection route between Sandford and Seabank substations.
The new 400,000 volt lattice pylon structures in and around the industrial area of Avonmouth are complete.
We’re using the traditional lattice design pylons in this area - at approximately 50 metres tall, they provide the height required across the River Avon and can navigate the tighter turning angles through Avonmouth’s industrial port area to complete and connect the final section of the route into Seabank substation.
We are expected to finish hanging the wires on the lattice pylons in a process known as stringing in March/April 2024.
Construction of the two new 76-metre tall lattice pylons on either side of the banks of the River Avon has been completed, with the final wiring works due in early April 2024. The new pylons are smaller than the two 91-metre pylons that once stood on either side of the bank of the River Avon.
To make way for the new 400,000 volt connection route, we are removing 67 kilometres of existing 132,000 volt lattice pylons operated by National Grid Electricity Distribution (formerly Western Power Distribution) between Bridgwater and Avonmouth as part of the Hinkley Connection Project.
During the summer, we waved goodbye to the two 91-metre pylons that once stood on either side of the bank of the River Avon and removed the line of pylons from Avonmouth village, including the pylon from the playground at Avonmouth C of E Primary School and Daisy’s Nursery.
Modifying the existing network near Seabank substation
We are continuing our work to modify the existing electricity network in and around Seabank substation. Our contractor, J Murphy and Sons, arereplacing nearby pylons at Crooks Marsh with new underground cables.
Thank you from everyone working on the project for your patience and understanding as we work to towards full completion of this project which will play such a key role in helping the UK meet its net zero ambitions by transmitting cleaner, homegrown, energy around the UK – enough to power six million homes and businesses.
Avonmouth timeline
Completed September 2020
Modify Avonmouth substation and existing overhead line to the east of the substation
Work carried out:
Replaced a small section of overhead line to the north of the substation with underground cables.
Constructed a new cable sealing end (CSE) pylon to connect the underground cables to the overhead line.
Changes inside Avonmouth substation to enable the connection of the new underground cables.
Reinstatement work including removal of the temporary construction compound and part of the haul road.
To be confirmed
Modify Seabank 132,000 volt substation and the existing overhead lines at Seabank
What we're doing:
Building a temporary construction compound and temporary entrances and access roads to allow construction traffic to enter the undergrounding site from the local highway.
Undergrounding a small section of the three existing overhead lines at Seabank. This will enable the new overhead line to pass safely overhead.
Building three pylons to connect the existing overhead lines to underground cables.
Modifying Seabank substation to enable the connection of the new underground cables.
Removing the existing overhead lines that are no longer needed in this area.
Mid 2021 to mid 2024
Build new 400,000 volt overhead line
What we're doing:
Building temporary entrances and access roads to allow construction traffic to enter site from the local highway.
Building a new overhead line from Sandford substation to Seabank substation (approximately 31.2 km).
In this area, we'll use a mix of steel lattice pylons and T-pylons.
Mid 2021 to mid 2024
Remove the existing 132,000 volt overhead line
What we're doing:
Removing the overhead line from the A368 in Sandford to Avonmouth substation, which will make way for, and minimise the visual impact of, the new connection.
Removing a small section of the existing overhead line to the east of Avonmouth substation.
To be confirmed
Modify Seabank 400,000 volt substation
What we're doing:
Extending the existing substation to enable the connection of the new overhead line.
Modifying the existing site access road.
Removing unnecessary electrical equipment.
Installing a perimeter flood defence wall with flood gates around the substation to help guard against tidal flood risk.