A submerged marine turbine design is proposed to harness the energy of the Kuroshio Current that flows northward along Japan’s east coast. The turbine is envisioned by Okinawa Institute of Science and Technology Graduate University researchers to operate in the middle layer of the current, 100 meters below the surface, where waters flow calmly and steadily, even during strong storms.

Tow tests trialed the ocean current turbine. Image source: Elsevier Ltd. Moored to the seabed, the three-bladed turbine positioned in the current would generate near-constant electricity. Rotor torque is canceled by a float at the top and a counterweight at the bottom. Towing tests conducted with a prototype verified the float and counterweight configuration and confirmed high hydrostatic stability and reliable electric power generation.

The design can be scaled up or down, depending on local conditions and needs, they researchers say. They aspire to build an energy farm featuring 300 turbines 80 meters in diameter with an expected output of about 1 GW.