National Grid launches North West London upgrade

National Grid has launched a major electricity infrastructure programme across North West London and surrounding areas that will strengthen network capacity and enable five new data centres requiring a combined 1GW of power.

The North West London Upgrade (NWLU) will involve a new substation, upgrades to existing substations, 60km of new cable infrastructure and reinforcement of more than 200km of overhead line.

The programme stretches from Sundon substation in Bedfordshire through Elstree in Hertfordshire to St John’s Wood in London and is intended to accommodate rising electricity demand from homes, businesses and digital infrastructure.

A significant element of the project will be delivered at Elstree, where National Grid will extend its existing 400kV gas insulated switchgear substation and construct a new 132kV facility at Letchmore Heath.

Together, the infrastructure will enable connections for five new data centres with combined demand of 1GW.

The scale of the requirement highlights the increasingly close relationship between data centre development and investment in the UK's electricity transmission infrastructure. Power availability and connection times have become major considerations for developers seeking to bring forward new facilities, particularly around established data centre clusters.

National Grid said the wider programme would increase network capacity and resilience while reducing constraint costs and supporting economic growth across North West London.

Joe Senior, project director at National Grid, said: “The North West London Upgrade is a nationally significant investment that will strengthen the electricity network, unlock new connections, support regional economic growth and help keep long term energy costs down for consumers.

“Working closely with our delivery partners and supply chain, we're bringing together substations, cables and tunnels, and overhead line reinforcement in a single programme to deliver the infrastructure needed to power future homes, businesses and digital industries as electricity demand rises.”

The programme will include reconductoring the 35km overhead line route between Sundon and Elstree, resulting in more than 200km of overhead line being upgraded.

National Grid will also install 60km of new cable infrastructure within the existing Elstree-St John’s Wood tunnel. The tunnel extends for more than 20km and was originally designed in the early 2000s with capacity for an additional cable circuit.

A series of contractors and equipment suppliers have been appointed to deliver the works.  Laing O’Rourke will undertake substation works at Letchmore Heath, Elstree and St John’s Wood, while the Hochtief-Murphy Joint Venture will deliver cable installation and tunnel upgrades.

Hyundai Electric will supply and install major electrical equipment including transformers, with Siemens Energy responsible for shunt reactors at Elstree.

Peter Lyons, Managing Director of Laing O’Rourke’s Europe hub, said: “These critical upgrades are just part of our ongoing work with National Grid to provide more secure energy for the UK.”

The NWLU joins other major National Grid programmes currently being delivered across the capital, including London Power Tunnels 2 and the North London Reinforcement scheme.

Communities close to the proposed Letchmore Heath substation will also be eligible for up to £530,000 for local projects under the Government's community funding arrangements for electricity transmission infrastructure.