London’s Hurst-Crayford power tunnel energised

National Grid has energised its 2.5km 275kV power tunnel between Hurst substation and Crayford, one of the transmission circuits in the 32.5km LPT2 route across south London.

“The previous cables between Hurst and Crayford were reaching the end of their operational life, having been commissioned in 1967 and having served London reliably for decades,” according to National Grid, which explained: “While the old cables were buried in shallower trenches in the streets, the LPT2 network carries power in three metre wide tunnels deep beneath the road network.”

Energy minister Michael Shanks was up the line at the New Cross sub-station for the switch-on.

“The London Power Tunnels show British infrastructure at its best and I congratulate the efforts of everyone involved,” he said.

President of National Grid Electricity Transmission Alice Delahunty and Minister for Energy Michael Shanks

New Cross is at the centre of two double circuits: 12km to Wimbledon’s sub-station and 18km to Hurst.

LPT2 tunnels are connected to the surface by vertical shafts between 9m and 15m wide and up to 55m deep, each covered by a head-house.

Also under construction now is the Bengeworth Road sub-station, which will use SF₆-free switch gear – SF₆ has one of the worst global warming ratings of all chemicals, rated at ~23,000 times worse than CO₂, and is virtually indestructible.

Completed in 2018, LPT, the original 32km London Power Tunnels project, transports energy across north London (credit Costain)