There’s an abundant source of power beneath the seas that’s unlike any other. To tap into it and in an attempt to obtain endless renewable energy, Japan is dropping a gigantic 330-ton turbine power generator onto the ocean floor just off the country’s coast. This beast is capable of withstanding the most powerful ocean currents and converting its flow into an unlimited supply of electricity. Kairyu is the name given to the 330-ton prototype, which roughly translates to “ocean current”. It had a 20-metre-long fuselage flanked by two cylinders of equal size, each holding a power generation system connected to an 11-metre-long turbine blade.
Ishikawajima-Harima Heavy Industries – now known as IHI Corporation – has been experimenting with the technology for more than a decade. In 2017, it partnered with the New Energy and Industrial Technology Development Organization (NEDO) to put their concepts to the test.
The Tokyo-based engineering firm finished a three-and-a-half-year test of the underwater Kairyu turbine in the waters of southwestern Japan in February 2022. It is expected to be operational sometime in the 2030s.
The device can orient itself to locate the most optimal place to generate power from the push of a deep-water current and feed it into a grid when it is anchored to the ocean floor by an anchor line and power cables.
To generate a substantial portion of its power, Japan is significantly reliant on fossil fuel imports. The country has huge tracts of coastline sea. The ocean swirls to the east under the power of the North Pacific gyre. When the gyre meets Japan, it forms the Kuroshio current, which is a relatively strong current. IHI estimates that if the energy in the current could be harnessed, it could generate roughly 205 gigawatts of electricity, which is comparable to the country’s current power-producing capacity.
Kairyu was meant to float 50 metres beneath the waves, with the drag caused providing the necessary torque to the turbines as it approaches the surface. Each of the blades also rotates in the opposite direction, ensuring that the gadget remains somewhat steady.
Kairyu was discovered to be capable of producing 100 kilowatts of power in a flow of two to four knots (about one to two metres per second). It may appear insignificant when compared to the 3.6 megawatts of an average offshore wind turbine.
Kairyu could soon have a monstrous sibling spinning 20-metre-long turbines to generate two megawatts, thanks to its proved ability to endure all nature can throw at it.
If everything goes according to plan, a farm of power generators might be flowing electricity into the grid by the middle of the next decade. However, it remains to see if Kairyu can scale up.
