or late. This appeared in 2010. And the device is definitely a turbine with wings, if the artist's rendering is accurate.
Minesto-kites
Minesto, a spin-off from Swedish automaker Saab, (in 2007) is developing what it calls it's "Deep Green" technology, underwater kites tethered to the ocean floor that could produce continuous energy from tidal flows. A single Deep Green turbine could produce up to 500 kilowatts of electricity. And tides are much more regular than winds, so that the energy produced would be less erratic and variable.
The kites have a 12m (almost 40 ft) wingspan. The kites would remain at least 20m (66 feet) below the surface, to prevent conflicts with ocean navigation and minimize visual impact. Tidal flow as low as 1.6 meters/second can be used to create the lift necessary to move the kite.
Since the underwater kite is anchored to the ocean floor, it is able to move at much faster speeds, which makes the turbine more effective, as it traverses back and forth in order to generate electricity. Although wind-based deepwater offshore power systems are difficult to install and operate, Deep Green tidal kites would be well suited for instalation in deeper waters. Furthermore, the underwater kites are much lighter and easier to install than the equipment needed for other deepwater generation systems. Deepwater generating systems have the additional expense and technical hurdles of transmitting the power over a greater distance. But the higher efficiency and more consistent generation offered by Deep Green could offset those drawbacks.
The company indicates the Deep Green system offers an operating cost of 0.06-0.14 Euros/kWh, as compared to 0.15-0.30 Euros/kWh for other tidal systems, and 0.10-0.12 Euros/kWh for offshore wind systems.
A scale model of Deep Green will be tested in Northern Ireland next year as the next stage of development for this system.
http://www.ecogeek.org/component/content/article/3159-using-underwater-kites-to-generate-power
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