Channel Tunnel interconnector

ElecLink awards Channel Tunnel interconnector construction contract

Image credit: Prysmian

A consortium of Balfour Beatty and Prysmian has been chosen to install a high-voltage direct current (HVDC) power transmission cable between Britain and France through the Channel Tunnel.

The ElecLink interconnector will have a capacity of 1000MW in either direction, increasing the scope for energy trading between the two countries. By taking advantage of the existing rail infrastructure of the tunnel, the project will avoid the cost and environmental impact of laying undersea cables.

This will be the world’s first installation of an HVDC interconnector in a live railway tunnel environment.

The €219m (£185m) contract was placed by ElecLink Ltd, a subsidiary of Groupe Eurotunnel.

Balfour Beatty will lead the design and installation of the project, with its share of the work valued at €140m. The international infrastructure group has experience in power transmission and distribution, construction and rail, including the London Power Tunnels ‘electricity superhighway’.

The installation of the HVDC interconnector will involve laying two 51km cables through the north tunnel and connecting them to converter stations in Peuplingues, northern France, and Folkestone, Kent.

Prysmian Group will be responsible for the design and manufacture of the ±320kV cabling for the HVDC symmetrical monopole circuit and for jointing services, and will also supply and install underground cables for the HVAC link to the Sellindge substation in Kent.

All the cables will be manufactured at Prysmian’s plant in Gron, France, which is a centre of excellence for extra high voltage (EHV) cables.

Balfour Beatty says it will make the construction programme more efficient by using offsite jointing facilities in Calais and Folkestone to assemble 2.5km sections of cable and by using computer modelling to plan the build. It has developed what it calls a unique system for the transportation and installation of the cable “which minimises risk, enables efficient installation and addresses the effect of high-voltage cable heat emissions in a live tunnel environment”. 

ElecLink has been selected and is part-funded by the European Commission as a Project of Common Interest that will contribute to the functioning of the internal energy market as well as promoting energy efficiency and the development of new and renewable forms of energy. It could also support the development of a potential European ‘super grid’ that would let the entire region share the costs of producing and distributing electricity.

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