Balfour Beatty – London Power Tunnel (LPT)

Project Overview

National Grid’s London Power Tunnel Scheme embarks upon a seven-year project to rewire the capital via deep underground tunnels, in order to meet increasing electricity demand and help London access the renewable energy of the future.

A new network of tunnels are being constructed between 20m and 60m deep below the road network. The tunnels carry high voltage (400kV) electricity cables and connect existing substations at Hackney; St John’s Wood; Willesden and Wimbledon. With intermediate shafts and headhouses located at key points along the tunnel route to ensure the safety of our workforce during construction, provide access to the tunnel for maintenance work and to store ventilation equipment which is required to cool the cables and regulate the temperature inside the tunnel.

Scope of Works

Working on behalf of Balfour Beatty, specialist APS operatives have performed throughout various aspects of the LPT scheme completed so far:

• East West Phase; 5km tunnel work Willesden – Kensall Green Cct 1 & Cct 2
• East West Phase; 5km tunnel work Kensall Green – St John’s Wood Cct 1 & Cct 2
• East West Phase; 6½km tunnel work St John’s Wood to Hackney Cct 1 & Cct 2
• North South Phase; 5km tunnel works Kensall Green to Wimbledon Cct 1 & Cct 2

Comprising of enabling and preparatory works; installing joint bay and transition steelwork; cable support saddles; cable cleating and intermediate spacing straps.

400kV Cable installation from the Shaft into the Tunnel using specialist equipment and machinery; ACIE (cable pulling/laying machine); push/pull rollers; hoist operations and Monorail Cable Delivery System (MCDS).

Fibre Optic Cable installation and testing.

APS staff are also actively involved in supporting the management and coordination of project, acting on behalf of and working alongside Balfour Beatty’s operational delivery team providing services such as:

• Construction Management
• Primavera P6 Planning Management
• Site Engineer