RSPB backs 12-mile reef electricity plant

A HUGE tidal barrage stretching from the Westcountry to South Wales would produce less electricity than a "reef" which would be less damaging to wildlife, a major study suggests today.

Conservationists are backing the 12-mile reef design which would link Minehead, on the Somerset coast, to Aberthaw in the Vale of Glamorgan.

It follows concerns that a barrage further upstream – capable of holding back the full height of the tide – would cause the destruction of internationally important wetland habitats.

For decades the idea of harnessing the power of the Severn has been held up as the ultimate green energy project capable of producing 5 per cent of the UK's total electricity.

Last year ministers launched a feasibility study into a series of projects varying in scale and cost, with several involving a barrage built across the width of the estuary. But a study commissioned by the RSPB and conducted by engineering consultants Atkins suggests that the reef design would be less environmentally damaging.

It would be bigger than the proposed Cardiff-Weston barrage scheme which would extend some 10 miles across the estuary. But the reef scheme would only hold back two metres of the tide and so not alter the tidal patterns to the same extent. The study suggested a tidal reef would cost £2 billion less than the estimated £15 billion for the barrage – which is itself an out-of-date estimate.

It is believed that it would not cause the same level of damage to the saltmarshes and mudflats upstream on which tens of thousands of birds over-winter, including dunlin, curlew, shelduck and redshank, oystercatchers and pintails.

Dr Mark Avery, director of conservation at the RSPB, said: "The Government must crack the problem of how to use the Severn's tidal power without harming its wildlife.

"We already know a Cardiff-Weston barrage would cost far more than almost any other form of green energy and seriously damage sites protected by law. A tidal reef could rein in that damage, cost much less and be built more quickly."

The reef would also be able to generate electricity for longer periods than the barrage and, therefore, meet power needs at peak demand times. It has been estimated that the Cardiff-Weston barrage could generate 17,000GW of clean energy a year – almost five per cent of the UK's needs. But the report suggests a tidal reef could produce 20,000GW. According to the reef's designers, it could open at set points to let container ships pass, would be less damaging to fish because the turbines would move slower, and could be built in sections to generate electricity sooner. Evans Engineering said its potential was "enormous". Rupert Evans said: "It would cut Britain's carbon emissions by around 12 million tonnes annually, create more than 30,000 jobs during construction and give a global lead for local manufacturing companies, particularly in the marine engineering sector."

A spokesman for the Department for Energy and Climate Change said: "We are still looking at all 10 options on our list of potential Severn tidal power schemes. As part of this work we have been doing our own study into the tidal reef proposal, but we will also consider this report by the RSPB."