Plans for a ten-mile barrage across the River Severn, which could generate 5 per cent of the UK’s electricity needs, moved closer yesterday with the appointment of an American engineering company to study the proposals.

Parsons Brinckerhoff, the company that built New York City’s first subway system and which is helping to build the Jumeirah Palm island in Dubai, will head a two-year assessment of the project, which is expected to cost up to £15 billion and could take a decade to complete.

PricewaterhouseCoopers is also to advise the Government on financing and ownership options, according to a statement from the Department for Business, Enterprise and Regulatory Reform.

The Parsons Brinckerhoff-led group will examine the scheme’s environmental impact and explore two main technologies — a conventional barrage, running between the English and Welsh coasts, and a tidal lagoon. Both would harness the enormous tidal range of the Severn, which at 14 metres is the second-highest in the world, to drive electricity-generating turbines.

A conventional barrage could be built at various locations, although a study in 1989 recommended one running ten miles between Lavernock Point, near Cardiff, to Brean Down, near Weston-super-Mare. This would have a capacity of 8,640MW and an estimated output of 17 terawatt hours a year — providing about 5 per cent of present UK electricity demand.

The alternative, a tidal lagoon, would need an artificial lake in an area of shallow water with a high tidal range. It would fill during a rising tide, gradually releasing the water afterwards to drive turbines. This would probably be a smaller scheme generating less power, but it might have a less damaging environmental impact.

John Hutton, the Energy Secretary, said: “A Severn tidal power project could be larger in size, output and cost than any other energy project in this country. It’s therefore vitally important that we undertake the most thorough and exhaustive study and contract the right companies.“

He added that the Severn barrage had the potential to deliver a substantial portion of ambitious new renewable energy targets set by the European Union in January. Under this, Britain has pledged to generate 40 per cent of its electricity from renewable sources by 2020, up from 4 per cent at present.

Jane Davidson, Minister for the Environment at the Welsh Assembly, said that the project would make an important contribution to helping tackle climate change.

According to the Sustainable Development Commission, a barrage across the Severn would produce clean and sustainable electricity for 120 years. It could have other uses, such as supporting a high-speed rail or road bridge.

However, the proposals are controversial. Opponents include Friends of the Earth and the RSPB, despite the project’s green credentials. The proposed Cardiff-Weston link would involve moving 18 million tonnes of seabed to create a level surface and would require 13 million tonnes of concrete, gravel and other aggregates. It would threaten the welfare of migratory fish and destroy tidal flats and saltmarsh, damaging the habitat of rare birds including the shelduck, teal, pintail, dunlin and redshank.

The Parsons Brinckerhoff-led consortium includes Black & Veatch, ABPmer, HR Wallingford, Hartley Anderson and George Corderoy.

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