What will the tidal lagoons do?
There are new plans in the UK that may pave the way for future developments across the world.
Six new tidal lagoons have been designed for construction across the UK. The lagoons will capture the incoming and outgoing tides behind giant sea walls and use the weight of the water to power turbines. They have been designed to produce enough energy to generate 8% of the UK's electricity and will cost around £30bn to build.
One of the lagoon sites in Swansea is said to stretch more than five miles, reach more than two miles out to sea and include up to 90 turbines.
The cost would be funded by electricity bill-payers under the existing government scheme to promote home-grown, low-carbon energy.
How does tidal lagoon power work?
The lagoons operate a system similar to a lock gate to alter the water level either side of a sea wall.
When the tide starts to rise, gates in the wall are closed and water builds up outside the lagoon.
When the tide is full outside the lagoon, the gates are opened and water rushes past the turbines to fill up the lagoon.
When the tide turns to go out, the gates are shut to hold the water inside the lagoon.
As low tide is reached outside the wall, the gates are opened to generate power again as water flows through from the raised water level in the lagoon.
A previous plan for a barrage on the River Severn to create tidal power was scuttled after environmentalists protested it would prevent the daily exposure of mud flats vital for wading birds.
The Swansea lagoon plan is more widely accepted as it does not impede estuaries and allows the tides to flow as normal. Some migrating fish will stray into the turbines, but the numbers of this will be tiny. The new sea wall will benefit fish by creating its own reef habitat.
The information in this article was extracted from the BBC website below: