The?huge Kairyu turbine, resembling an airplane, includes two 36-foot-long counter-rotating turbine fans and a central housing unit containing a buoyancy adjustment system. The system involves the use of a turbine placed on the ocean floor, where it can take advantage of stable deep-sea currents that flow steadily with little fluctuation in speed and direction. By rotating in opposite directions, the two turbine blades cancel out rotary torques—the force?that can cause an object to rotate about an axis—and act to maintain the generator’s stable position underwater. The 330-tonne prototype is designed to be anchored to the seafloor at a depth of around 30-50 metres (100-160 feet).

While the use of renewables is advancing in fits and starts, this system could provide an almost unlimited stream of energy, without relying on the wind or sun.

In February 2022, IHI successfully completed a 3 1/2 year-long test in the waters of southwestern Japan. IHI argues that the trial has opened the door for the wider use of deep-sea ocean currents to generate power.