Minesto says it has unveiled a way of using an underwater kite that can harness tidal power. The principle of the technology can be explained as a two stage process.
The first stage increases the relative flow speed entering a tidal turbine. When the tide hits the wing it creates a lift force, since the kite is mounted to the ocean bed with a tether and is controlled by a rudder, the kite can be taken in the desired trajectory. The method increases the flow velocity into the turbine with 10 times the current speed.
The second stage uses a conventional plant to convert kinetic energy into electrical power. The net result is increased tidal power from a smaller package.
The tidal power plant weighs 13-14 tons/MW and electricity generation costs using Deep Green are in the range of €0.06-0.14/kWh.
Minesto’s tidal concept has been verified on a scale of 1:10 and Minesto is now working on the next prototype in a 1:4 scale. It will be tested outside the coast of Northern Ireland.
The tidal power technology will contribute to “a substantial increase of power from the tides with its ability to produce energy from areas where other technologies are less efficient,” Minesto says.
The main reason for this is the extended site areas available when looking at sites with a current velocity of 1.2-2.2m/s and depths between 60-120 m. In the UK, Deep Green alone could add 18 TWh of electricity potential utilised from tides.
The existing owners of Minesto, Saab Group, Midroc New Technology, Verdane Capital and Encubator have recently invested additional capital to accelerate the development of the slow current tidal power technology.
In total they have invested just under €2 million into the company while additional funding has been received from both Swedish and UK governments.