Engineers energised National Grid’s £1 billion London Power Tunnels 2 (LPT2) project in south London on 5 August.
Energisation of the LPT2 project sees 2.5km of new high voltage 275kV network made live between Hurst substation and Crayford. The tunnel route is at an average of 35 metres below ground, work was completed by National Grid’s tunnel boring machine, dubbed ‘Christine’, in October 2023.
The previous cables between Hurst and Crayford, installed in 1967, were reaching the end of their operational life. They were also in shallower trenches than the new network. LPT2 carries power in three metre wide tunnels with vertical shafts 9-15 metres wide and up to 55 metres deep at key points along each circuit, each covered by a headhouse.
The headhouses and shafts provide ventilation and safe access for project teams, meaning less construction and maintenance disruption as well as easier future upgrade potential.
At the start of 2023, National Grid confirmed it would be using green technology to reduce the use of sulphur hexafluoride (SF6) across the LPT project; also under construction on the LPT2 route is a new substation at Bengeworth Road, which is the UK’s first to be built using SF6-free gas insulated switchgear technology.
On the same day that part of the LPT2 was energised, energy minister Michael Shanks visited New Cross substation, a key site at which work is ongoing on the project’s other double circuits. One is between Wimbledon substation and New Cross, 12km, and the other is between New Cross and Hurst, covering 18km.
Alice Delahunty, president of National Grid Electricity Transmission, said: “We were pleased to welcome the minister at such a milestone moment for London Power Tunnels, and demonstrate the ongoing work to reinforce the city’s network.
“There’s still a way to go on the project, but the Hurst-Crayford circuit seeing volts for the first time is a tremendous achievement for our National Grid teams and supply chain partners.
“It’s hard to overstate what an engineering challenge it has been to build over 30km of tunnels under London to upgrade and futureproof the capital’s electricity supplies, so the project’s progress to date is a real testament to all those involved.”
LPT2 was launched in 2020 and has seen Nation Grid work closely with supply chain partners to progress the project, which is projected to complete in 2027. It is the second phase of an endeavour to reinforce London’s electricity network in readiness for future demand.
Shanks said: “The London Power Tunnels show British infrastructure at its best and I congratulate the efforts of everyone involved, as this new circuit switches on to power up homes and businesses across the capital.
“It is feats of incredible engineering, such as this, that will be the driving force behind our race to become a clean energy superpower and help to revive communities across the UK with new skilled jobs.”
