National Grid powers ahead with third London circuit energised bringing clean power to 340K homes in stunning underground project

National Grid has energised the third circuit of its landmark London Power Tunnels 2 project, bringing clean electricity to over 340,000 homes in South London. The newly activated transmission circuit runs 18 kilometers deep underground, marking a critical step in securing London’s energy infrastructure for decades to come.

National Grid Activates Third London Power Tunnels Circuit

The newly energised transmission circuit connects New Cross substation in Southwark with Hurst substation in Bexley, running 18 kilometres beneath South London through tunnels reaching depths of 50 metres. This represents one of two double-circuit high voltage links planned for the wider project, supplying power onwards to UK Power Networks’ distribution network.

The circuit replaces one of two buried cables that have served the capital reliably since the 1960s. According to Joe Senior, National Grid’s project director, this energisation marks another step in reinforcing London’s electricity network and ensuring the city maintains safe and reliable power into the future.

The London Power Tunnels 2 Project Specifications

Three Milestone Energisations Completed in Record Timeline

The London Power Tunnels 2 project has achieved three major energisation milestones in rapid succession. The first circuit between Hurst and Crayford was energised in August 2024, followed by the second Hurst-Crayford circuit in March 2025, and now the New Cross-Hurst connection in December 2025.

These successive milestones represent over 5 million working hours from more than 3,000 people collective effort since the project’s inception in 2019. The HOCHTIEF-MURPHY Joint Venture partnership with Taihan, Balfour Beatty, and Linxon coordinated this complex underground infrastructure delivery across seven South London boroughs including Wimbledon through to Hurst.

Community Benefits and STEM Investment Through London Power Tunnels

National Grid embedded significant community engagement throughout the project, reaching 147,000 students through dedicated schools programmes tackling social mobility and closing STEM skills gaps. The company invested £525,000 in local grant funding supporting organizations ranging from Lambeth food growing charities to Bexley Cricket Club’s solar panel initiative.

Underground construction crossed beneath critical London infrastructure including Northern Line, Victoria Line, and DLR routes, requiring precision engineering and coordination. The Deputy Mayor of London for Energy and Environment, Mete Coban, emphasized this approach ensures South London homes, schools, and local communities receive reliable power for the future while maintaining London’s status as a green energy leader.

What This New Circuit Means for London’s Energy Future?

National Grid’s expansion of London’s transmission network addresses the capital’s exploding electricity demand driven by electric vehicle adoption, heat pump installations, and renewable energy integration. The new 18-kilometre circuit serving 340,000 properties provides redundancy—if older cables fail, this circuit supplies power while replacements occur, eliminating widespread blackout risk.

With second New Cross-Hurst circuit coming online in early 2026, London Power Tunnels 2 provides infrastructure foundation for Britain’s Clean Power Plan targeting 126 GW clean generation connected by 2030. National Grid’s broader £51 billion investment in green infrastructure through RIIO-T3 regulation period to March 2029 positions the UK’s largest city to become a zero-carbon electricity hub while supporting millions of homes transitioning away from fossil fuels.

Sources

• National Grid – Official press release on London Power Tunnels 2 third circuit energisation December 2025
• Utility Week – Coverage of London Power Tunnels infrastructure milestones and South London coverage
• New Civil Engineer – Technical analysis of LPT2 project specifications and delivery timeline

Patrick Graham

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