You could call it lunar power, and certainly it’s long been eclipsed by the sun and wind for renewable energy. Yet, after nearly 90 years of frustration, the time of tide – of which Britain has the greatest resources of any country on earth – might finally be about to arrive, and by an unexpected route.
On Monday, a House of Commons select committee will produce yet another report on proposals for a tidal barrage across the Severn estuary that could generate 5 per cent of the country’s electricity. But it’s just possible that this much-touted solution – which has been unsuccessfully revived more than a dozen times since first proposed in 1925 – will be pipped to the post by a little-publicised scheme for a chain of lagoons around the estuary which, its promoters say, will produce more energy at about half the cost.
Overwhelmingly powered by the moon, tides rise and fall with metronomic predictability – a rare and invaluable attribute for a renewable source. The Severn has the second greatest tidal range in the world, after Canada’s Bay of Fundy, as Atlantic sea water accelerates on meeting the continental shelf, pushing a huge volume into a relatively shallow pool.
Other exceptional sites stud our coasts – including Liverpool and Morecambe Bays, the Solway Firth and the Wash – most of them conveniently close to towns and cities that can use the power. Indeed, the UK has half the tidal power resources of the whole of Europe.
The Commons Energy and Climate Change Committee will assess the latest barrage scheme, an 11-mile dam, containing 1,026 underwater turbines, stretching from Lavernock Point, near Cardiff, to Brean, near Weston-super-Mare. It is designed to have the capacity of more than three nuclear power stations, or more than 3,000 wind turbines, and to save the emission of 7.1 million tons of carbon dioxide a year.
Britain's tides could become an energy goldmine