Costain earns National Grid tunnelling contract

National Grid has decided to award Costain the GBP 200 million contract for 32km of tunnel beneath London. The plan is to lay cables that will enable National Grid to deal with increased demand and better handle rising energy flows across the city.

The project calls for two tunnels, each between three and four metres in diameter and approximately 20 to 60 metres below ground. The first, at 20km, will run from the National Grid substation in Willesden via Kensal Green, St. John’s Wood and Islington to the substation in Hackney. The shorter 12km tunnel will run from Kensal Green to Wimbledon. Work on the tunnels will commence in late 2010 and is expected to be finished by the end of 2014. The energisation of the new cables is anticipated to have taken place by November 2018.

Construction director of National Grid, Michael Dyke has said that the new programme will be built below the existing network ‘minimising disruption’. The contract also includes the design and build of associated head-houses and installation of ventilation equipment.

Programme and project management contracts were awarded to Arup and Mott McDonald earlier this year.