National Grid completes erection of new T-pylons for Hinkley Connection Project

All 116 new T-pylons being constructed as part of National Grid’s Hinkley Connection Project have been erected – a new milestone for the project. 

The first T-pylons were constructed in March 2022, but now the project is almost complete thanks to the erection of the final T-pylons. These will carry low-carbon energy between Hinkley Point C to Seabank power station, providing electricity to six million homes and businesses in the South West of England. 

The last of the T-structures’ 232 diamond-shaped insulators – which hold the high-voltage conductors in a diamond ‘earring’ shape – was recently lifted by crane into place on a T-pylon between Yatton and Kenn in North Somerset by National Grid and principal contractor Balfour Beatty.

T-pylons are quicker to erect than traditional lattice pylons, and 47 more T-pylons were completed – including installation of the conductors – by the end of 2022. 

36 new T-pylons between Woolavington and Loxton were energised in early 2023, meaning high voltage electricity is now running along the new T-pylons, through cables under the Mendip Hills Area of Outstanding Natural Beauty and via the newly built substation at Sandford.

At the same time work began to build the 68 T-pylons running north of Sandford substation to Portbury. With the hanging of the final diamond insulator, those 68 T-pylon structures are now complete.

All the T-pylons will be energised by the end of 2024. Before then, conductors will be hung from the T-pylons, and the last of 249 traditional lattice pylons and 67km of overhead wires will be removed from the landscape to make way for the new electricity connection.

Roxane Fisher-Redel, Senior Project Manager for National Grid on the Hinkley Connection Project, commented, "National Grid’s T-pylons are the first new design for overhead electricity lines in over a century and will play a central role in connecting low-carbon energy to millions of people when Hinkley Point C begins generation.

"Erecting all the 116 T-pylon structures is a huge milestone and now we look ahead to 2025 and full completion of this project, which will play such a key role in transmitting cleaner, homegrown energy around the UK – enough to power six million homes and businesses."

The T-pylons were designed to reduce the visual impact of the 57km connection route on the landscape as a direct response to community feedback.

At 35m high, they are a third shorter than National Grid’s traditional lattice transmission pylons and take up less room on the land.