National Grid Partners With HMJV, Laing O’Rourke, Siemens Energy and Hyundai Electric on NWLU

National Grid Partners With HMJV, Laing O’Rourke, Siemens Energy and Hyundai Electric on NWLU

(IN BRIEF) National Grid has launched the North West London Upgrade, a major electricity transmission project designed to strengthen network resilience, increase capacity and support future economic growth across North West London and surrounding areas. The programme spans from Sundon substation in Bedfordshire to Elstree substation in Hertfordshire and onward to St John’s Wood substation in London, and includes a new substation, substation upgrades, 60 kilometres of new cable infrastructure, more than 200 kilometres of upgraded overhead line, and reinforcement of existing transmission assets. The project will enable new connections, including five data centres equivalent to 1GW of demand, while supporting reliable electricity supply for homes, businesses and digital industries. Delivery partners include HMJV, Laing O’Rourke, Siemens Energy and Hyundai Electric, while communities near the new Letchmore Heath substation will be eligible for up to £530,000 in government-backed community funding for local projects.

(PRESS RELEASE) LONDON, 14-Aug-2026 — /EuropaWire/ — National Grid has launched the North West London Upgrade, a major electricity transmission investment designed to strengthen network resilience, support economic growth and enable new connections across North West London and surrounding areas.

The project will reinforce the transmission network across a route running from Sundon substation in Bedfordshire to Elstree substation in Hertfordshire, and onward to St John’s Wood substation in London.

The complex programme includes new and upgraded substations, new cable infrastructure and reinforcement of existing overhead lines.

National Grid said the works will increase network capacity, improve the resilience of electricity supplies and help keep energy bills down by reducing constraint costs.

The investment is also expected to support future economic growth as electricity demand rises across North West London and the wider region.

The project will enable new connections, including five data centres, while helping ensure that homes, businesses and digital industries have access to reliable electricity now and in the future.

The North West London Upgrade adds to National Grid’s wider programme of work across the capital, which also includes London Power Tunnels 2 and the North London Reinforcement scheme.

The programme includes upgrades to Sundon substation in Bedfordshire and reconductoring of the 35-kilometre Sundon–Elstree overhead line.

It also includes extending the existing Elstree gas insulated switchgear substation, constructing a new Letchmore Heath gas insulated switchgear substation next to Elstree, and installing a new 400kV cable circuit within the existing Elstree–St John’s Wood tunnel.

Further works include upgrades to the Elstree–St John’s Wood tunnel and headhouses, as well as reinforcement of the existing St John’s Wood substation.

Across the Sundon to Elstree route, more than 200 kilometres of overhead line will be upgraded.

In addition, 60 kilometres of new cable infrastructure will be installed within the existing Elstree–St John’s Wood tunnel.

The tunnel, which stretches for more than 20 kilometres, already carries the longest alternating current transmission cables on the England and Wales transmission network.

It was originally designed in the early 2000s to accommodate an additional cable circuit if required in the future.

In Hertfordshire, the project will extend the existing 400kV Elstree GIS substation and build the new 132kV Letchmore Heath GIS substation next door.

The new infrastructure will connect five new data centres, representing the equivalent of 1GW of demand.

National Grid is delivering the project with several major partners.

Laing O’Rourke has been appointed to deliver substation works at Letchmore Heath, Elstree and St John’s Wood.

The Hochtief-Murphy Joint Venture, known as HMJV, will deliver cable installation and tunnel upgrades.

Hyundai Electric will supply and install major electrical equipment, including transformers.

Siemens Energy will be responsible for shunt reactors at Elstree substation.

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.

He said National Grid is working closely with delivery partners and the supply chain to bring together substations, cables, tunnels and overhead line reinforcement in a single programme.

Senior added that the project will deliver the infrastructure needed to power future homes, businesses and digital industries as electricity demand increases.

Raj Kundan, Project Director at HMJV, said the joint venture is proud to continue supporting National Grid in the delivery of critical national energy infrastructure.

He said HMJV will bring its solutions and collaborative “One Team, One Spirit” approach to the programme, while working with National Grid and enterprise partners to leave a positive legacy for those connected with the scheme.

Peter Lyons, Managing Director of Laing O’Rourke’s Europe hub, said the work builds on the company’s partnership with National Grid.

He noted that Laing O’Rourke has also been appointed as construction partner to The Great Grid Upgrade, Wimbledon Asset Replacement, and the Margam and Port Talbot substations.

Lyons said the company will use digital tools to support safe and efficient delivery on site, adding that the upgrades form part of Laing O’Rourke’s ongoing work with National Grid to provide more secure energy for the United Kingdom.

In line with government guidance, communities near the new Letchmore Heath substation will be eligible for up to £530,000 to spend on local projects.

The funding is intended to support projects that improve the social, economic and environmental wellbeing of the community and deliver long-term local benefits.

Through the North West London Upgrade, National Grid is investing in electricity infrastructure intended to support rising power demand, strengthen regional resilience and enable the connections needed for future homes, businesses and digital services.

Media Contact:

email: media.uk@nationalgrid.com
Tel: 01926 656 536

SOURCE: National Grid