Artists’ impression of what the completed tidal fence might look like. Given the height of the ship in the illustration, the fence wouldn’t exactly be unobtrusive. Not that the Severn Barrage would be either.
A fairly recent report said that the Severn Barrage should not be built, based on high cost and the possible damage to local ecosystems. However, alternative tidal power plans for the region are now being investigated, according to the BBC.
A Tidal ‘Fence’ Rather Than a Dam
The main idea, being put forth by the Severn Tidal Fence group, is rather than a full tidal barrier a line of underwater turbines would be built, with spaces between the turbine groups large enough for commercial shipping to pass, as well allowing for the migration of salmon and reducing the risk of flooding upstream by reducing high tide levels upstream from the fence. Mudflat areas used by migratory birds would also be protected.
Though lower in capacity than the Severn Barrage, the Tidal Fence would have a capacity of 1.3GW—equal in capacity to an average nuclear plant—and be able to produce approximately 1% of the country’s electric supply. Unlike the barrage, which would produce most of its power and high and low tide, the fence would be most productive in the middle of the tidal cycle.
Total cost for the fence would be approximately £3.5 billion, with between 8,000 and 13,000 jobs created directly and indirectly by its construction. The barrage is expected to cost around £15 billion to build.
via :: BBC News
Severn Tidal Barrage Should Not be Built, Report Claims
Commercial-Scale Tidal Power Turbine Begins Feeding Electricity to Grid
Wave and Tidal Power Could Supply 20% of UK Needs