National Grid’s £1 billion ($1.22 billion) London Power Tunnels (LPT) project has achieved a major milestone with its final tunneling breakthrough at Eltham substation in Greenwich, south of the River Thames. A 140-tonne Tunnel Boring Machine reached the end-point of its journey on 2nd October. Now all 32.5km (20.2 miles) of the tunnels are complete and the next stage of the much-needed upgrade to the UK capital city's transmission system can proceed.
This is the installation of 200km (124 miles) of high voltage cable, which is already underway. Construction of the tunnels began in March 2020 with the tunneling works undertaken by National Grid’s delivery partner HOCHTIEF-Murphy Joint Venture.
Alice Delahunty, president of National Grid Electricity Transmission, said, “Our London Power Tunnels project has achieved a lot since it kicked off in 2020, but the final tunneling breakthrough at Eltham is a particularly remarkable moment.
“This complex engineering endeavor is now really taking shape, with completion of tunneling now physically linking our sites across South London for the first time and meaning we can move on to the next chapter to progress our vital cabling work.
“The outstanding effort by our project teams and suppliers is strengthening London’s electricity network and making sure it safely, reliably and efficiently powers homes and businesses in the capital for years to come.”
Tunneling on the LPT project was completed in three sections between existing National Grid substations – Wimbledon-New Cross; New Cross-Hurst; and Hurst-Crayford – using four Tunnel Boring Machines named Christine, Caroline, Edith and Grace.
The project is due to be fully operational by 2026, with the aim of reinforcing and future-proofing London’s electricity network – and supporting Britain’s transition to net zero – as power demand in the capital grows.