Severn Tidal Barrage

Plans to construct a tidal barrage across the River Severn, producing hydroelectric power, have been scrapped due to the current financial situation. The Severn tidal project would cost Ł30 billion.
The plans envisaged a 10-mile long tidal barrage across the Severn Estuary stretching from Cardiff to Weston-super-Mare, incorporating some 200 turbines, able to generate about 5% of the UK's annual electricity requirements.
The project originally received government backing and would play a leading role in plans to meet climate-change targets (40% of UK electricity should be generated from renewable sources by 2020 if EU targets are to be met).
Opposition to the project has grown over recent years and a coalition of 10 groups including the National Trust, the RSPB and WWF (but not Greenpeace) say the barrage would be a mistake, both economically and environmentally.
The groups commissioned a report from the economics consultancy Frontier Economics, that concluded that more power could be generated more cheaply by using other green technologies.
The report argues that the financial cost of the project has been substantially underestimated and is likely to cost much more than the widely quoted Ł15bn. For instance that figure does not take into account the cost of land acquisition in Cardiff and Weston-super-Mare, or the creation of new wildlife habitats.
The report also argues that the cycle of the tides in the Severn means that a barrage would not necessarily provide electricity at peak times, and thus, the amount of power that the barrage would contribute to the National Grid has been over-estimated.
In terms of the environmental benefits of the scheme, the report says that huge amounts of CO2 would be emitted during the building of the barrage. An estimated 5m tonnes of CO2 during construction and another 5m tonnes emitted during transport of the materials.
The barrage would destroy nearly 86,486 acres (35,000 ha) of highly protected wetlands across the estuary. The land that would be submerged is home to about 68,000 birds in winter, including huge flocks of dunlins and shelducks, together with Bewick's swans, curlews, pintails, wigeons and redshanks. In summer, many breeding birds favor the estuary include curlews, shelducks and oystercatchers. The estuary is also important to sea-life and at least 30,000 salmon and tens of thousands of shads, lampreys and sea trout use the estuary to reach spawning grounds in the Usk and Wye rivers. Eels swim back down these rivers to reach spawning grounds at sea and millions of elvers return in the spring.