In 2017, Japan tested a twin-turbine machine in the Kuroshio Current; the floating device later showed it could generate 100 kW from the Pacific’s “river”

In August 2017, engineers dropped a 330-ton machine into one of the ocean's fastest currents and waited to see if it would make it out alive. It held up better than that. It generated electricity. The twin-turbine device, named Kairyu, was confirmed capable of a rated 100 kilowatts of power during a towing test simulating the Kuroshio Current, and went on to generate power directly from the current itself once moored on-site off Kagoshima Prefecture, according to a joint announcement by Japan's New Energy and Industrial Technology Development Organization (NEDO) and IHI Corporation. That test was the basis for a technology that researchers continue to refine today.

The current that behaves like a river