The UK National Grid’s Hinkley Connection Project has completed all 116 of its new T-pylons, which will connect six million homes and businesses in the South West to the Hinkley Point C NPP.

The last of the T-structures’ 232 diamond-shaped insulators – which hold the high-voltage conductors in a diamond ‘earring’ shape has now been installed in place. The first T-pylon to be built was constructed in September 2021. T-pylons are quicker to erect than traditional lattice pylons, and 47 more were completed – including installation of the conductors – by the end of 2022.

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 system.

Roxane Fisher-Redel, Senior Project Manager for National Grid on the Hinkley Connection Project, said: "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."

The T-pylons are 35 metres high – a third shorter than National Grid’s traditional lattice transmission pylons and take up less room on the land. They were designed to reduce the visual impact of the 57km connection route on the landscape in response to community feedback.

Hinkley Point C, when complete, will comprise two 1,630 MWe EPR reactors supplied by EDF. Construction began in December 2018 but the project has faced delay challenges. In May 2022 EDF, following a review of the project, confirmed that the plant would begin operating a year later than planned and could cost up to £3bn ($3.7bn) more to build than originally budgeted. This put the start date for unit 1 at June 2027, with the cost estimated at £25-26bn, an increase on the previous estimate of £23bn.

Image: National Grid's new T-pylons will connect six million homes and businesses in the South West to the Hinkley Point C NPP (courtesy of National Grid)