The barrage, which was yesterday hailed as Britain's flagship engineering project of 21st century and is forecast to generate nearly 5 per cent of UK electricity, was initially proposed in 1849. It has long been considered a white elephant because of its enormous cost - estimated at between £14 and £15 billion. But recent support in the Government's Energy White Paper and yesterday, at the launch of the SDC's report on tidal energy, has resurrected the case for the project.
Environmental groups reacted with dismay to the proposals. A spokesman for Friends of the Earth, which has long advocated the building of 'tidal lagoons' in the estuary instead of the barrage, said he was 'appalled':
'We urgently need to promote renewable energy initiatives but they need to be the right ones. A combination of a smaller barrage and tidal lagoons would produce more energy with more flexibility, are cheaper and would cause less damage,' said Neil Crumpton, Energy campaigner for the group.
Tidal lagoons are oval-shaped, enclosed sections of the estuary, ringed with rock walls. At high tide, water flows in through turbines set in the lagoon walls, generating electricity. At low tide, water flows back out through the turbines, generating electricity again.
Asked by the Ecologist why the SDC had not given more support to the prospect of tidal lagoons, which are predicted to cause far less environmental damage, be significantly less expensive and generate more power, head of the Commission Jonathon Porritt said:
'We're not against tidal lagoons, but the fact is that we have sod all evidence to go on.'
The SDC are, however, recommending that a smaller demonstration tidal lagoon be built in Swansea Bay.
The SDC's recommendations are conditional on the Government finding alternative habitats to replace those which will be destroyed by the barrage, and being able to finance the project entirely from the public purse.
This article first appeared in the Ecologist October 2007