Avonmouth

Current construction activity

Date from

Date to

Activity

February 2022

Late 2025

Seabank substation and nearby pylons at Crooks Marsh

June 2021

Late 2024

Access to public footpaths and rights of way

May 2021

2024

Building new pylons

2018

Ongoing

Roadworks and traffic management

Overview – Winter 2022

In May 2021, National Grid started work to build the new 400,000 volt overhead connection along the northern section of the Hinkley Connection Project between Sandford and Seabank substations.

This work brings us another step closer to connecting high-voltage electricity from Hinkley Point C and other sources to six million UK homes and businesses.

As part of the Hinkley Connection Project, we’re working in partnership with Western Power Distribution (WPD) to make changes to their local electricity distribution network.

In February, our contractor, J Murphy and Sons, start work to make changes within WPD’s substation at Seabank, and to replace nearby pylons at Crooks Marsh with new underground cables.

We recognise that our construction activity causes local impact and work with our contractors to limit that as much as possible.

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.
 

Take a look at our detail map

Projects 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.