London Power Tunnels Map

Project Overview

In Spring 2020 we embarked upon a seven-year, £1 billion project, to rewire South London via deep underground tunnels. This vital work will help keep Londoners connected to safe and reliable electricity supplies.

In total, 32.5km of 3m diameter tunnels are being constructed deep below the road network between Wimbledon and Crayford, which will carry high voltage electricity cables.

Most of the electricity supply in South London is currently transmitted through underground cables, traditionally found just below the road surface. Work to maintain them is carried out at street level and can be disruptive.

By housing new electricity cables in deep underground tunnels, there will be a number of benefits:

  • Less disruption during construction as the majority of works will take place deep underground
  • Future repairs and maintenance work can be carried out without disrupting traffic, residents and businesses
  • Additional cables can be installed in the tunnels to meet future demand

Tunnel construction is well underway, with the project due to be complete and fully operational in 2027. It follows the successful completion of phase 1 in 2018, which was a seven-year, £1 billion programme, building 32km of tunnels and two new substations in North London.

Timeline

Time period

Site activity

Wimbledon 
May 2022Works began on site
Summer 2022Works to the existing headhouse building were carried out, including the removal of the roof
July 2022TBM breakthrough from Kings Avenue site
Early 2023Tunnel repair works, cable bracket installation and final fittings to the tunnel 
Autumn 2023Tunnel boring completed along entire route of project
Late 2023Headhouse construction completed
January 2024 – September 2025Site will be occupied
2026Project expected to be fully operational
Kings Avenue 
Spring 2020Works began on site
May 2021 – July 2022The tunnel was built
August 2022 – October 2022The initial tunnel clean to Wimbledon took place
April 2023TBM breakthrough from New Cross site
Autumn 2023Tunnel boring completed along entire route of project
January 2024Headhouse construction began
2026Project expected to be fully operational
Bengeworth Road 
December 2020 – January 2021Three public engagement events held with local residents
August 2021 – May 2022Shaft construction works
February 2022Engagement with local residents on substation and headhouse design
Summer 2022TBM breakthrough from New Cross site
Autumn 2023Tunnel boring completed along entire route of project
Winter 2022 – 2025Substation and headhouse construction
2026Project expected to be fully operational
New Cross 
June 2019Site preparation including ground remediation works to remove unwanted materials and contaminated land began
January 2022 – September 2023Tunnel construction to Kidbrooke took place
Autumn 2023Tunnel boring completed along entire route of project
March 2024Construction on two headhouses began
2026Project expected to be fully operational
Kidbrooke 
Spring 2022Works began on site
Summer 2022Shaft construction works began
Autumn 2023Tunnel boring completed along entire route of project
January 2024Works began to install cable brackets inside the tunnels from Eltham to Kidbrooke, then Kidbrook to New Cross
March 2024Headhouse construction began
2026Project expected to be fully operational
Eltham 
October 2021 – May 2022Shaft construction works
June 2022TBM breakthrough from Hurst site
Mid-2023Cable installation in the Eltham to Hurst tunnel concluded
September 2023TBM breakthrough from New Cross site
Autumn 2023Tunnel boring completed along entire route of project
March 2025Headhouse expected to have been built
2026Project expected to be fully operational
Hurst 
February 2021Work began on site
January 2022Completed 2km of tunnel boring
February 2023TBM passed from Hurst to Crayford
March 2023Headhouse construction works began
Autumn 2023Tunnel boring completed along entire route of project
2026Project expected to be fully operational
Crayford 
July 2021Digging of the shaft began
February 2023TBM breakthrough from Hurst site
Autumn 2023Tunnel boring completed along entire route of project
Late 2023Headhouse construction began
2026Project expected to be fully operational
Shafts and headhouses

Intermediate shafts and headhouses are required at key points along the route of the tunnel. The tunnel boring machines will link these points as it progresses along the routes.

The shafts and headhouses are needed for the following reasons:

  • Health and safety – it is essential to have access points to ensure the safety of our workforce during construction. The shafts are also used to access the tunnel for maintenance work once the tunnel is built and operational.
  • Ventilation – ventilation equipment, in the form of fans, is required at some sites to cool the cables and regulate the temperature inside the tunnel.

The headhouses will be designed in order to minimise their visual impact on the local area. For example, materials are being chosen to complement the surrounding environment in agreement with the local council.

London Power Tunnels Phase 1

In February 2011, we embarked upon a seven-year, £1bn infrastructure project to rewire the Capital, the first major investment in the electricity transmission system in London since the 1960s. The project, known as London Power Tunnels, saw the construction of 32kms of underground tunnels, running from Hackney in the east to Willesden in the west, and from Kensal Green to Wimbledon in the south. The newly built 10 transmission circuits can now carry some 20% of the Capital’s electricity demand and stretched out they would run all the way around the M25.

Key facts about London Power Tunnels phase 1

  • The depth of the tunnels varies between 20-60metres. The tunnels go under tube lines, canals and rivers.
  • 192km of 400kV cable was installed in the tunnels, along with 30km of 132kV cable.
  • There were 14 access shafts dug to support the tunnelling work, which was completed in 2015.
  • Over 700 people were employed at the busiest time on the project, with forty apprenticeship tunnelling roles created over the project’s lifespan. In total, it took over 6 million people hours to complete LPT.
  • We recycled 99% of the material excavated during the construction of the tunnels, with the excavated 500 cubed metres of London clay enough to fill Arsenal’s Emirates stadium, which is just down the road from the project’s Highbury substation.
  • We are proud of the positive legacy we left with phase 1 of the London Power Tunnels project where we engaged with over 30,000 students; it is our aspiration to build on this through phase 2.

Field worker inside london power tunnels

Contact us

If you would like to discuss the project in greater detail or have any questions, please contact our community relations team using the details below:

Call our Freephone helpline number: 0800 783 2855 (lines open 9am to 5pm, Monday to Friday)

Email: [email protected] 

Write to: FREEPOST NATIONAL GRID