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

March 2022

Site set-up and enabling works

April 2022 – August 2022

Works to existing headhouse inc. roof removal to facilitate TBM removal

August 2022 – September 2022

Completion of Kings Avenue to Wimbledon tunnel

TBM 1 dismantle and removal

August 2022 – October 2022

Initial tunnel clean from Kings Avenue to Wimbledon

October 2022 – January 2023

Headhouse works to reinstate roof following TBM removal 

Cable bracket and monorail installation from Kings Avenue to Wimbledon

March 2023

Demobilise from site

Kings Avenue

May 2021 – August 2022

Tunnel construction to Wimbledon (drive 1)

September 2022 – November 2022

Initial tunnel clean to Wimbledon

November 2022 – February 2023

Cable bracket and monorail installation from Kings Avenue to Wimbledon

Early 2023 (Jan/Feb)

TBM arrival from New Cross (drive 3), dissemble and removal

Feb 2023 – April 2023

Cable bracket and monorail installation from Kings Avenue to Wimbledon

Bengeworth Road

September 2021 – June 2022

Shaft construction

New Cross

July 2021 – early 2023

Tunnel construction to Kings Avenue (drive 3)

September 2021 – January 2022

TBM 4 arrival, assembly and launch. Drive to 400m

January 2022 – end 2023

Tunnel construction to Eltham (drive 4)

January 2023 - February 2023

Initial tunnel clean to Kings Avenue

Kidbrooke

June 2022- August 2022

Site set-up

August 2022 – November 2022

Shaft construction

Winter 2022 – March 2023

Headhouse construction

Eltham

October 2021 – May 2022

Shaft construction

August 2022

August – September 2022

Completion of tunnel from Hurst to Eltham

TBM 3 dismantle and removal

September 2022 – end 2022

Cable bracket and monorail installation from Eltham to Hurst, followed by installation of tunnel steelwork               

End 2022

Full tunnel clean Hurst - Eltham

Hurst

October 2021 – August 2022

Tunnel construction to Eltham (drive 2B)

August 2022 - September 2022

Initial tunnel clean to Eltham

August 2022 – October 2022

Refurbishment and reinstallation of TBM 3

October 2022 – April 2023

Tunnel construction to Crayford

Early 2023 – June 2023

Cable installation from Hurst to Eltham

Crayford

September 2021 – April 2022

Site set-up and enabling works inc. vegetation clearance

April 2022 – November 2022

Shaft construction

March 2023 – June 2023

TBM arrival from Hurst. Dismantle and removal.

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