London Power Tunnels is a project by

National Grid plc National Grid plc is a British multinational electricity and gas utility company headquartered in London, England. Its principal activities are in the United Kingdom, where it owns and operates electricity and natural gas transmission networks ...

to reinforce the electricity transmission network in

London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...

, UK, by constructing more than 60 km of new deep-level tunnels carrying high-voltage cables. The new network of tunnels replaces a series of ageing power cables, most of which were buried directly beneath roads. These were becoming unreliable, difficult to maintain without disrupting traffic, and were unable to meet future demand for electricity. The new tunnels allow the power cables to be upgraded and maintained without disruption to traffic and residents on the surface. The project is divided into two phases: the first phase involved constructing tunnels connecting substations at

Wimbledon Wimbledon most often refers to: * Wimbledon, London, a district of southwest London * Wimbledon Championships, the oldest tennis tournament in the world and one of the four Grand Slam championships Wimbledon may also refer to: Places London * ...

, Hackney, and

Willesden Willesden () is an area of northwest London, situated 5 miles (8 km) northwest of Charing Cross. It is historically a parish in the county of Middlesex that was incorporated as the Municipal Borough of Willesden in 1933, and has formed ...

, and was completed in 2018. The second phase involves linking Wimbledon substation with

Crayford Crayford is a town and electoral ward in South East London, England, within the London Borough of Bexley. It lies east of Bexleyheath and north west of Dartford. Crayford was in the historic county of Kent until 1965. The settlement deve ...

, and is expected to be completed in 2026.

Phase 1

The first phase involved constructing 32 km of tunnels linking substations from

in the south west to Hackney in north east of London, at a cost of £1 . The 3–4 m diameter tunnels were dug by

tunnel boring machines A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore throu ...

and run 20–60 m below street level. The tunnels were constructed by a joint venture between

Costain Group Costain Group plc is a British construction and engineering company headquartered in Maidenhead, England. Founded in 1865, its history includes extensive housebuilding and mining activities, but it later focused on civil engineering and commerci ...

and

Skanska Skanska AB () is a multinational construction and development company based in Sweden. Skanska is the fifth-largest construction company in the world according to ''Construction Global'' magazine. Notable Skanska projects include renovation of t ...

. This phase linked Wimbledon and Hackney to substations at

St John's Wood St John's Wood is a district in the City of Westminster, London, lying 2.5 miles (4 km) northwest of Charing Cross. Traditionally the northern part of the ancient parish and Metropolitan Borough of Marylebone, it extends east to west from ...

, St Pancras, and

Islington Islington () is a district in the north of Greater London, England, and part of the London Borough of Islington. It is a mainly residential district of Inner London, extending from Islington's High Street to Highbury Fields, encompassing the ar ...

. It also involved the construction of two new substations at Seven Sisters Road in

Highbury Highbury is a district in North London and part of the London Borough of Islington in Greater London that was owned by Ranulf brother of Ilger and included all the areas north and east of Canonbury and Holloway Roads. The manor house was situ ...

, and at

Kensal Green Kensal Green is an area in north-west London. It lies mainly in the London Borough of Brent, with a small part to the south within Kensington and Chelsea. Kensal Green is located on the Harrow Road, about miles from Charing Cross. To the w ...

, to feed traction power to

Crossrail Crossrail is a railway construction project mainly in central London. Its aim is to provide a high-frequency hybrid commuter rail and rapid transit system crossing the capital from suburbs on the west to east, by connecting two major railway ...

. As well as the main power transmission circuits for the National Grid, the tunnels also carry circuits from Islington substation to St Pancras and Seven Sisters Road, forming part of the London power distribution network operated by

UK Power Networks UK Power Networks is a distribution network operator for electricity covering South East England, the East of England and London. It manages three licensed distribution networks (Eastern Power Networks, South Eastern Power Networks and London Pow ...

. The project was started in February 2011 and the first section was energised five years later in February 2016. The project was officially opened by Prince Charles in February 2018.

Phase 2

The second phase (known as LPT2) started in spring 2020 and will span 32.5 km from Wimbledon to Crayford in south-east London. The tunnels will be between 3–3.5 m in diameter, 10–63 m below street level, with most being around 30 m deep, and is expected to cost £750m. The contract for the second phase was awarded to a joint venture between Murphy Group and

Hochtief Hochtief AG is a German construction company based in Essen, North Rhine-Westphalia, Germany.Elstree to St. John's Wood Cable Tunnel * New Cross to Finsbury Market Cable Tunnel * Lower Lea Valley Cable Tunnels

References

External links

Official Website
{{Major Development Projects in London Tunnels in London Electric power infrastructure in England Electric power transmission in the United Kingdom Tunnels underneath the River Thames