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Avonmouth
Current construction activity
Date from | Date to | Activity |
February 2022 | Late 2025 | |
June 2021 | Late 2024 | |
May 2021 | 2024 | |
2018 | Ongoing |
Overview – Summer 2022
In July 2022, we started work on building 27 new lattice pylons in the northern section of the Hinkley Connection from Sandford to Seabank, near Avonmouth.
National Grid is using lattice pylons in and around Avonmouth, rather than the T-pylon design seen elsewhere on the Hinkley Connection route because at 50 metres high, the lattice design provides the height required across the River Avon, and means National Grid can navigate the tighter turning angles that are needed on the route between the River Avon and Seabank substation.
Our contractor, Balfour Beatty, erected the first lattice pylon next to the M49 on Tuesday 19 July 2022. Most pylons take up to four weeks to assemble with those near the River Avon taking approximately six weeks.
We expect all pylons to constructed and the wires in place by 2023. During the work to install the wires between the pylons, we’ll use controlled lifting systems and erect scaffolding where the wires cross over roads.
Our contractor, J Murphy and Sons, started work in February 2022 to modify the existing electricity, replacing nearby pylons at Crooks Marsh with new underground cables and make changes within Seabank substation. This work is set to be completed in late 2023.
To make way for the new 400,000 volt connection, National Grid is removing 67 kilometres of existing 132,000 volt overhead wires and 249 along the new connection route.
In 2021, we removed seven pylons from across the M49. During 2023, we we’ll take down another line of pylons between Portishead and Avonmouth substations, removing pylons from a residential area, including those near Avonmouth C of E Primary School and Daisy’s Nursery.
Thank you from everyone working on the project for your patience as we continue our work to deliver electricity safely, efficiently, and reliably, and support the UK’s ambition to achieve net zero by 2050.
Contact our community relations team to register for project updates direct to your inbox.
Avonmouth timeline
Completed September 2020
Modify Avonmouth substation and existing overhead line to the east of the substation
Work carried out by Western Power Distribution (WPD):
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.
This work will be done by Western Power Distribution.
Mid 2021 to mid 2025
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 2025
Remove the existing 132,000 volt overhead line
What we're doing:
Removing Western Power Distribution’s 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.