T-pylons herald UK low-carbon electricity era

Wires to carry low carbon energy onto the UK electricity network have now been installed on 36 of the Hinkley Connection Project’s new T-pylons and 48 have now been built between Bridgwater and Loxton in Somerset, according to National Grid.

The so-called 'stringing' process is now complete on the pylons between Woolavington and Loxton and work is due to start in April to install the conductors on 12 T-pylons between Bridgwater and Woolavington. All 48 are set to be energised in October.

The Hinkley Connection stretches 57km from Hinkley Point C to Seabank power station. It is made up of sections of traditional lattice pylons at Shurton and Avonmouth and 116 new T-pylons, with a section of underground cable between Loxton and Sandford, running under the Mendip Hills Area of Outstanding Natural Beauty.

There will be a total of 116 T-pylons along the route. Construction work has begun on the remaining 68 T-pylons on the northern section between Sandford and Portbury and they will be completed, including stringing, by 2023. 

Engineers have been busy putting in place the conductors that will carry the low carbon energy onto the electricity network - and providing a new more environmentally friendly alternative to the A-frames which have dominated the UK landscape since the first one was installed in 1928.

T-pylons herald new era of low-carbon electricity on road to UK net zero

T-pylons have a single pole and T-shaped cross arms, which feature suspension diamond insulators - like ‘earrings’ - which hold the wires, or conductors.

The conductors are transported to site on large drums, weighing up to 7.5 tonnes and 2.5m high. Teams of engineers first pull a steel braided rope between sections of up to 12 T-pylons through circular running blocks suspended from the diamond-shaped insulators.

The heavier conductors are then attached to the rope via a rectangular headboard, which is then pulled back through the running blocks using large winches. Engineers control the speed of the winches to guide the conductors into position before they are fixed to the insulators.

T-pylons form part of a suite of technologies and approaches to mitigate visual impact, including alternative lattice pylon designs and different types of underground and subsea cable systems – with each approach chosen where it’s operationally possible and cost efficient for electricity consumers.

The span of cables between each T-pylon is up to 360m and the conductors are installed in sections of up to 12 T-pylons at a time, with each section taking around two weeks to ‘string’.

James Goode, Project Director for National Grid Electricity Transmission said National Grid is at the heart of the transition to net zero and the conductors will carry low carbon electricity onto the network for millions of people across the UK for years to come.

"The Hinkley Connection Project will be ready to connect six million homes and businesses in the south west and beyond with low-carbon electricity generated by Hinkley Point C and other sources of low carbon energy in 2024.

Liam Cave, Operations Director at Balfour Beatty, said it had reached a 'landmark moment' in edging closer to low-carbon electricity for UK homes and businesses.