Ocean current power generation is a harvesting method of ocean renewable energy. This energy regeneration technology is intended to effectively utilize the Kuroshio Current and is suited to Japan.
For over a decade, Japanese heavy machinery maker IHI Corporation has been working on Kairyu, a sea turbine that harnesses energy in deep ocean currents. Developed in collaboration with New Energy and Industrial Technology Development Organization (NEDO), the world’s first 100 kW-class ocean current turbine can withstand the strongest currents in the ocean and convert this flow into an inexhaustible source of energy.
After three and a half years of testing off the coast of Kuchinoshima Island, Kagoshima Prefecture, and obtained data for commercialization, the turbine should be expected to be up and running sometime in the 2030s.
Kairyu weighs 330-ton and features a 66-foot long central cylinder with two extra ones on each side, each carrying 36-foot variable-pitch twin-blade turbine rotors attached to them. Each rotor spins a 50kW generator. The sea turbine is designed to operate around 50-meter (164-foot) below sea level to generate power efficiency, having a mechanism that utilizes depth measurements from water pressure sensors and a buoyancy adjustment device built into the central pod to enable the optimum position underwater to be maintained.
A massive fuselage allows the entire apparatus to float while moored at a depth of around 50-meter (164-foot) below sea level. The floating generator anchored to the bottom of the sea takes advantage of the balance between its buoyancy and the drag caused by the ocean current, thereby generating electric power while floating at any desired depth.
During the demonstration earlier this year, IHI Corporation was able to generate 100 kW of stable power achieved at a rated flow speed of 1.5 m/s. The company will continue to develop the ocean current turbine with the aim of realizing an ocean current power generation farm equipped with a full-scale production turbine with a rated output of 2 MW and a turbine rotor blade diameter of approximately 40-meter (131-foot).