Avonmouth
National Grid is continuing to work on the northern section of the Hinkley Connection route. This route runs between Sandford and Seabank substations, passing west of Nailsea and east of Tickenham village.
This is part of the Hinkley Connection Project, a significant investment in the region’s electricity network. The project aims to connect new sources of low-carbon energy to homes and businesses to the new Hinkley Point C power station in Somerset.
Upcoming construction works
- Seabank susbtation modification: Works are taking place to modify the 400,000 volt Seabank substation to replace redundant equipment used for the previous iteration of the substation and replacing this with upgraded equipment. Commissioning works are also ongoing at this time.
- Current work includes removing temporary roads, access points, and work areas used during construction.
As we continue construction works in this area, you might see more construction traffic on local roads. We will keep you informed about any required traffic management updates in advance.
Avonmouth Timeline
Completed September 2020
Modification of the Avonmouth substation and existing overhead line to the east of the substation
Work Included:
- Replacing a small section of overhead line to the north of the substation with underground cables.
- Constructing 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.
Completed Mid 2024
Modification of the Seabank 132,000 volt substation and the existing overhead lines at Seabank.
Work Included:
- 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.
Construction of a new 400,000 volt overhead line
Work Included:
- 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).
Removal of the existing 132,000 volt overhead line
Work Included:
- 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.
Completed Late 2024
Extension of the Seabank 400,000 volt substation
Works include:
- Extending the existing substation to enable the connection of the new overhead line, including the introduction of new AIS equipment with switchgear.
2025 – Late 2026
Works taking place:
Modification of the Seabank 400,000 volt substation
Works include:
- Modify the existing site access road.
- Remove redundant electrical equipment, such as protection and control equipment and switchgear designed for the previous iteration of the substation, and replacing this with upgraded equipment.
- Conduct commissioning tests of electrical infrastructure at Seabank substation
- Reinstatement works to restore access to public footpaths and rights of way. To facilitate the above works, roadworks and traffic management may be in place. Reinstatement is due to complete in late 2026.
Thank you
Thank you from everyone working on the project for your patience and understanding as we work to toward completion. This project will play 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.
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