'Underwater kite' aims to turn energy tide  

CNN has a report on a novel Swedish designed tidal power turbine - 'Underwater kite' aims to turn energy tide.

A new type of tidal turbine which its creators describe as an "underwater kite" has taken a step closer to becoming commercially available.

"Deep Green," developed by Swedish start-up Minesto, has just secured €2 million ($2.5 million) from investors to fund testing scheduled to start in 2011. The technology comprises of a turbine attached to a wing and rudder which is tethered to the ocean floor by 100 meters of cable.

Anchoring "Deep Green" and steering the tethered "kite" enables the turbine to capture energy from the tidal currents at ten times the speed of the actual stream velocity, say Minesto. When operational, the turbine is expected to generate 500 kilowatts of power.

One of the big advantages of their technology, Minesto executives say, is its small size -- 12 meters for the wingspan and one meter for the turbine -- relative to other tidal-energy designs.

According to Minesto's chief technical officer, Ted Rosendahl, this means that "Deep Green" can operate efficiently at sites with low current velocities and also at greater depths, allowing tidal energy to be implemented in new stretches of sea water.

The company hope to begin trials of a scale model in 2011 at Strangford Lough, in County Down, Northern Ireland -- which is already home to a commercial tidal power device operated by UK renewable energy company, SeaGen.

Rosendahl is confident that a commercial model of "Deep Green" will be available within four years but he says obstacles still remain.