26 Nov 2008 05:11:23
Tidal reef 'cheaper, better' than Severn Barrage
A tidal reef would provide more electricity with less impact on natural life and at a lower cost than the proposed Severn Barrage, according to the Royal Society for the Protection of Birds (RSPB).
The mouth of the River Severn has a 45 foot difference between high tide and low tide, which the government and energy companies would like to exploit to generate renewable electricity.
Currently about ten proposals are being reviewed, with the most famous being the ten-mile barrage, which proponents claim would generate 17,000 gigawatt hours (GWh) a year, or five per cent of the UK's energy requirements.
However, conservationists are concerned that the barrage, which traps water at high tide, before letting it out through gates to power high-speed turbines, would have an impact on local wildlife.
The RSPB claims that saltmarshes in the area, on which 68,000 birds feed, would be destroyed by the proposal, while fish would be at risk from the rotating turbine blades.
It proposes instead a 12-mile tidal reef, further out to sea, which it claims would generate 20,000 GWh and cost £2 billion less.
Professor Rod Rainey, the report author, said: "We believe this scheme could be more powerful but less costly than other plans being put forward, particularly the Cardiff to Weston barrage."
It would also preserve saltmarshes as it would lie low in the sea and its slow moving turbines would be less of a hazard for fish.
Developing the tidal resource could significantly contribute to government plans to generate 15 per cent of electricity from renewable sources by 2020.http://www.rspb.org.uk/Images/atkins_tcm9-203975.pdf