Swedish tidal energy developer Minesto reports that results of quarter-scale sea trials of its Deep Green tidal technology, ongoing since 2013 at its test facility in Northern Ireland, correspond to full power production for a full-scale power plant.

The scale model of the system designed to produce electricity from low-velocity ocean and tidal currents generated an output of more than 3 kW at a tidal current velocity of 0.8 m/s. This corresponds to full power production for a full-scale 0.5 MW power plant at 1.75 m/s current velocity, the company says.

The seabed-anchored energy kite exploits low velocity currents. Image source: MinestoNear-term testing will focus on a 3-meter-long composite wing. The updated quarter-scale design features a revised hydrodynamic shape to increase the power production performance.

Deep Green is an underwater kite comprising a wing with a rudder to steer the turbine to face in the direction that will allow it to capture the maximum amount of tidal energy and generate electricity. The kite flies in a figure eight and travels up to 10 times the water current speed.

As the kite moves, water flows through the turbine and electricity is produced in the gearless generator. The electricity is transmitted through a cable in the tether attached to the wing, and via sub-sea cables to shore.