Plans for sea energy device Searaser
A Devon inventor's electricity from seawater generator could be sited at 200 points around the UK coastline.
Energy firm Ecotricity wants to develop a commercial Searaser for testing off Falmouth in Cornwall and put hundreds around the coast in five years.
Dale Vince of Ecotricity said the potential was "enormous".
The Searaser machine works by using wave energy to pump water up to container tanks and the water is then released to a hydro-electric turbine.
Searaser is the brainchild of British engineer Alvin Smith from Dartmouth.
He came up with the idea about 10 years ago while he was playing with an inflatable ball in a swimming pool.
Searaser pumps seawater using a vertical piston between two buoys - one on the surface of the water, the other suspended underwater and tethered to a weight on the seabed.
As the ocean swell moves the buoys up and down, the piston works like a bicycle pump to send seawater through a pipe to an onshore turbine to produce electricity or to a coastal storage reservoir.
It can then be released through a generator as required.
Mr Smith: "There are over 150 reservoirs on our cliff tops already around the south west.
"A lot of these are becoming available.
"The tanks can be large or the size of a family swimming pool."
He said that a full size machine would be about 1m wide and 12m deep and cost up to £250,000.
The ideal site for machines would be in water about 25m deep near a cliff face.
He is hoping the test machine will be installed off Falmouth in Cornwall by the end of the year.
An area off Falmouth, called the Fabtest site, has been designated in 2011 for wave testing machines.
Another test machine could be sited off Portland in Dorset where a reservoir is available.
The machines would protrude about 1m above sea level.
Mr Smith said: "There would be no trawling around them but there would be no trouble with line fishing or lobster pots.
"We might even increase the habitat because weights holding them onto the seabed are quite big and they can induce more life in the sea."
Ecotricity believes Searaser addresses two of the biggest barriers to the deployment of renewable energy, cost and variable output.
Mr Vince said: "We believe Searaser has the potential to produce electricity at a lower cost than any other type of energy, not just other forms of renewable energy but all 'conventional' forms of energy too."
It believes that 200 sites could generate enough energy to power about 230,000 homes.