National Grid’s T-Pylons project powers up
National Grid has successfully energised 36 of the world’s first T-pylons between Bridgwater and Loxton in Somerset, UK.
High-voltage electricity – up to 400,000 volts – is now passing through the T-pylons, a newly constructed electricity substation at Sandford and 8.5km of underground cables through the Mendip Hills Area of Outstanding Natural Beauty (AONB).
A further 80 T-pylons will be completed and energised by 2024.
The uniquely shaped pylons have been constructed as part of the £900 million ($110.5 million) Hinkley Connection Project, a new 57km high-voltage electricity line that will connect six million homes and businesses to new sources of home grown, low carbon energy.
Construction of the first T-pylons began in September 2021, with all the conductors or wires that transmit the energy between Bridgwater and Loxton installed by March 2022. The conductors are now energised and transporting electricity around the National Grid’s electricity network.
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First major redesign in nearly a century
The T-pylon design, the first major UK redesign since 1927, has a single pole and cross shaped arms, and is around a third shorter than traditional high-voltage pylon design with a smaller ground footprint.
The new design was selected from over 250 designs entered in an international competition run in 2011, organised by the Royal Institute of British Architects and government (the then Department of Energy and Climate Change).
With a need for new energy infrastructure to enable progress towards net zero, the competition sought a new design to reduce impact on the local environment and surroundings.
Along with offshore routes, underground cabling and continued use of traditional lattice pylons, the new T-pylon design is a potential technology choice for future projects.
Each new transmission network project is assessed on a case-by-case basis, with the technology used by National Grid based on planning policy and regulations set by Ofgem as well as engineering, environmental and cost considerations.
T-pylons: An element of Hinkley
The Hinkley Connection Project is a new high-voltage electricity connection between Bridgwater and Seabank near Avonmouth. It is considered a significant investment in the region’s electricity network and will enable connection of new sources of low-carbon energy to homes and businesses, including Hinkley Point C.
The project began in 2009; the new high-voltage 400kV overhead line featuring the new T-pylons is one element of the Hinkley Connection.
The full route is made up of 14 interconnected project stages which are set for completion by 2025.
It includes modifications to the existing local network by removing 67km of overhead wires (including 249 pylons) and 8.5km of underground cables through the AONB, which will leave the area free of pylons for the first time since the 1960s.
Significant milestones from the project have included:
- Construction and commissioning of two substations, at Shurton and Sandford
- Installation of 8.5km of underground cable under the Mendip Hills Area of Outstanding Natural Beauty
- Construction of Loxton Cable Sealing End, next to the M5 where the T-pylons connect into the underground cables
- 150 existing pylons removed to date, 249 in total will be removed from the Somerset landscape as part of the project
- Energisation of the new high-voltage electricity connection between Bridgwater and Sandford, including 36 of the world’s first T-pylons.
The project has to date awarded more than £1.1 million ($1.4 million) in community grants to 75 different projects in areas nearby.
The Hinkley Connection project began construction in 2018 will be ready to connect to Hinkley Point C by the end of 2024, with the project complete, including reinstatement at the end of 2025.
