Three firms are chasing the lion’s share of a £600 million scheme to build four cable tunnels in London for National Grid.
London accounts for about one-fifth of the country’s electricity demand and the gas and electricity distributor has said this need is forecast to grow by five per cent a year - more than double that of the rest of the country.
National Grid is planning to start building the 4 m diameter tunnels next year and Costain, Murphy and Morgan Est are all working up bids for a tender return in September.
The first part of the deal is worth about £473 million and will involve boring 27.5 km of tunnel in two sections - including a continuous tunnel of 20 km - from Hackney in the east to Willesden in the west, due to be completed in 2015.
The winning team will also be responsible for a 7.1 km stretch between Hurst and Eltham in south-east London, which will be finished by 2014.
A fourth tunnel, which runs for 7.4 km between Wimbledon and Kensal Green in south-west London, is being tendered separately and construction will run from late 2009 to 2016.
This package will carry a price tag of about £127 million. All the tunnels will house 400kV cables that will feed into National Grid’s substations in Hackney, St John’s Wood, Wimbledon, Willesden, Hurst and Eltham.
A National Grid spokeswoman said: “The total construction time for all four tunnels will be six years, starting on the Hurst to Eltham route in spring 2009 and completing the Wimbledon to Kensal Green route in 2016.
“The work is vital to meet increasing demand in the capital. Additional cables can be installed in the tunnels if required in the future.”
But the company will have to compete with other projects for tunnellers. These include the £16 billion Crossrail project and Thames Water’s planned sewage overflow tunnel called Thames Tideway which is worth £2.3 billion.
One bidder for the National Grid work admitted it faced a challenge to get tunnellers on board for the work, which will see tunnels sunk to an average depth of between 12 and 60 m, including one stretch below the River Thames.
He said: “It’s going to be very busy and we don’t really have too many tunnelling people around. Something will need to be done to increase the skills base.”
Industry body TunnelSkills has already said the industry will need 15,000 tunnellers if the host of jobs planned are to be completed on time.
It expects recruits from Eastern Europe to fill some gaps, while Portuguese tunnellers who worked on the Channel Tunnel Rail Link are also expected to return.
Crossrail is setting up an academy to help staff its tunnelling works, which run 42 km in total from Paddington in west London across to Stratford and the Isle of Dogs in the east.
TunnelSkills is also promoting the use of an NVQ Tunnel Safety passport for personnel working underground.
Analysis: Investment needed for tunnel vision
By Tom Foulkes
With Crossrail finally getting the go ahead and the Thames Tideway project on the horizon, these are exciting times for tunnel engineering.
The problem we now face is finding enough people to get the job done.
Successive governments’ stop-start approach to planning for all major infrastructure projects has undermined skills investment and left us with a desperate shortage of engineers and technicians.
We only have to consider how many years it has taken for the Crossrail project to get off the ground to see why industry confidence has been so eroded. Initiatives such as Crossrail’s skills academy, as well as provisions in the new Planning Bill are hopefully a sign that the situation is being addressed, but we must not become complacent.
We need major investment across our transport and utilities networks.
An awful lot of tunnels need to be dug and we must ensure we have the right people to dig them.
Tom Foulkes is director general of the Institution of Civil EngineersTo download a PDF of the London cable tunnel route, click on the resource box on the right hand side of the page