The development of the underwater kite began at the University of Groningen (RUG).
Tidal energy company SeaQurrent is currently installing an underwater-kite in the Waddenzee, offshore the Netherlands, near the island of Ameland.
The local flow is relatively low, 1.0-1.5 m/s, but predictable and water still has a density, 832 times higher than air, which more than compensates for the low flow. The size of the kite is 7 x 12 m, which should suffice for 500 kW or 700 households.
SeaQurrent has a pontoon, 1 kilometer out of the coast at Cornwerd, where they developed the system, that is now ready for prime time.
The system operates with 2 kites, that act as a sort of yo-yo using a winch: when one is moving away from the suspension point, the other one is pulled towards it. The electricity generated during moving away from the suspension point delivers more electricity than it costs to pull the kite in again. The kites move in 8-shape trajectories, like a kite in the air. With a maximum speed of about 14 kmh, like a bicycle, they won’t act as fish killers.
The principle isn’t new, other similar systems were tested, like the Swedish Minesto or Dutch Ampyx Power. New is that SeaQurrent kite can operate in waters as shallow as 10 m.
The system won’t solve the world’s energy problems, but it could become a niche product for coastal areas, where 700 households should have little trouble funding this relatively simple device.
The cable required to connect the kite to the grid in Ameland has been installed,