National Grid energises third London Power Tunnels circuit to boost city’s electricity network

• One side of a new double circuit between New Cross and Hurst now live
• New high voltage circuit runs deep underground across South London for 18km
• Marks key step in keeping the city connected to safe and reliable power into the future

Electricity is now flowing through a new part of National Grid's £1 billion London Power Tunnels 2 (LPT2) project following the energisation of a key transmission circuit, further reinforcing the network in the city.

The first of two new circuits that connect National Grid's New Cross substation in Southwark with its Hurst substation in Bexley is now live, running for 18km beneath South London through tunnels up to 50 metres deep.

This new link replaces one of two buried cables that have reliably served the capital since the 1960s, with the other to be replaced when the second New Cross-Hurst circuit goes live in the new year.

At almost 22km, the original links have historically been the longest AC transmission cables on the entire England and Wales network – an accolade that will pass to the Elstree-St John's Wood cable circuit in the north of the city.

The newly energised transmission circuit serves around 340,000 properties in South East London, supplying power onwards to UK Power Networks' distribution network via National Grid's substations at New Cross and Hurst.

Energisation of the first two of LPT2's circuits took place between Hurst and Crayford in August 2024 and March 2025, along a 2.5km route forming the project's most easterly section.

In total the LPT2 project, which began in 2019, spans 32.5km across seven South London boroughs from Wimbledon to Hurst. It has been delivered by National Grid in partnership with HOCHTIEF-MURPHY Joint Venture (HMJV), Taihan, Balfour Beatty and Linxon.

The LPT2 project at a glance:

• 32.5km of tunnels across seven South London boroughs between Wimbledon and Hurst.
• 200km of high voltage cable installed in the tunnels – enough to stretch from London to Cardiff, or circle around the M25.
• 30m average tunnel depth, with the route crossing under rivers and rail lines, including under the Northern and Victoria tube lines and the DLR.
• 147,000 students reached through a schools programme tackling social mobility, closing STEM skills gaps, and opening green energy career pathways for underrepresented youth.
• £525,000 in funding to local community groups and organisations through a grant programme, including a Lambeth food growing charity and Bexley Cricket Club.
• 5 million working hours from over 3,000 people across the project since 2019.

Deputy Mayor of London for Energy and Environment, Mete Coban, said:

“It's fantastic to see electricity flowing through a new part of the London Power Tunnels. This circuit ensures homes, schools and local communities in South London are one step closer to having the power they need for the future, as we continue building a better London for everyone.”

Joe Senior, project director at National Grid Electricity Transmission, said:

“Switching on this circuit on a new part of our London Power Tunnels 2 project is a significant achievement for our engineering and delivery teams. This milestone in the project marks another step in reinforcing London's electricity network and keeping the city connected to safe and reliable power into the future.”

Raj Kundan, HMJV project director, said:

“Our team is proud to be a part of the LPT2 Project 13 enterprise that has jointly achieved energisation of this new circuit and delivered National Grid's desired scheme outcomes. The scheme continues to set the benchmark for complex major infrastructure delivery, as well as leaving a lasting positive legacy to local communities and the wider industry – which as HMJV we've been glad to support through our ‘One Team, One Spirit' approach.”

Tony Wilson, managing director of Balfour Beatty's Power Transmission and Distribution business, said:

“This latest milestone marks a major step forward in National Grid's £1 billion London Power Tunnels project. Delivered safely and to the highest standards alongside National Grid and our partners, this new link deep beneath South London will bolster the resilience of the power network in the city, powering 340,000 homes, schools and businesses to meet increasing demand.”

Yousef Chamaneh, Country Manager, Linxon UK, said:

“This milestone is the result of the collective effort and ingenuity of exceptional teams; thanks to our Linxon colleagues on site and behind the scenes, and to our valued enterprise partners and supply chain who consistently go the extra mile. National Grid's leadership on LPT2 exemplifies how partnership can deliver world class infrastructure. We're proud to play our part safely, responsibly and with unwavering commitment to the communities we serve.”

Jongmin Song, CEO of Taihan Cable & Solution, said:

“The energisation of New Cross and Hurst will strengthen the reliability of London's power supply, and we are proud to celebrate this significant milestone with the enterprise partners. Taihan remains fully committed to enhancing the UK's transmission network through continued cooperation and our proven cable technology.”

The current London Power Tunnels project is the second phase of a massive endeavour to reinforce the capital's electricity network in readiness for growing electricity demand.

It follows the completion in 2018 of the first phase – a seven-year, £1 billion project to construct 32km of tunnels and two new substations to rewire the network in North London.