By Ashley Karen
As part of National Grid’s £1bn London Power Tunnels phase 2 project to rewire London, construction work has begun on a new high-voltage substation in south London.
Construction engineering company Lixon and National Grid are constructing the new 400kV electricity substation at the Bengeworth Road site in the London borough of Lambeth.
Since 2021, National Grid has been working at the Bengeworth Road site, where it has completed a deep vertical tunnel access shaft construction. The shaft will link the site to the new London Power Tunnels phase 2 route from Wimbledon to Crayford.
In total, 32.5km of 3m diameter tunnels are being constructed deep below the road network between Wimbledon and Crayford, which will carry high voltage electricity cables.
The high voltage substation will be constructed by utilizing Hitachi Energy’s SF6 free gas-insulated switchgear technology in the UK first. The technology forms part of National Grid’s purpose to have no SF6 in electrical assets by 2050. Although SF6 gas is a potent greenhouse gas with a high global warming potential, it is used throughout the electricity industry as an insulating medium in switchgear.
The substation will balance voltage on the network, assist power homes and businesses across London and allow more future renewable electricity to join the grid.
Onur Aydemir, London Power Tunnels project director claimed: “Breaking ground at Bengeworth Road marks the first major milestone in the development of this new substation, which forms part of our £1bn project to completely rewire South London.”
Chris Goodwin, Linxon chief operating officer pointed out: “We are proud to be supporting National Grid in the delivery of this critical infrastructure, providing secure and reliable power to London, where we are deploying Hitachi Energy’s EconiQ SF6 free solution, further demonstrating Linxon’s commitment to sustainably power the world with carbon free energy.”
National Grid’s London Power Tunnels project is a seven-year project that will replace ageing high-voltage cables and rewire South London through deep underground tunnels. Tunnel construction is well underway with the project due to be finished and fully operational in 2027.
In February this year, the Christine tunnel boring machine (TBM) completed its drive in a flooded shaft at Crayford in southeast London after moving 2.5km from the project’s Hurst site.
As reported, the project’s TBM Edith finished its 6.3km journey from the New Cross substation to Kings Avenue this week.
Only one more drive is left as part of the tunnelling works, driving 11.1km from New Cross to Eltham. National Grid has planned TBM Grace’s arrival at Eltham for November 2023.
The fourth tunnel boring machine on the project, Caroline, completed its 5.6km journey last year in July, excavating from the Kings Avenue shaft in Brixton to Wimbledon.
Hochtief Murphy Joint Venture has carried out the project’s tunnelling.
