Japanese researchers from Okinawa Institute of Science and Technology (OIST), led by Professor Shintake, have began a project titled “Sea Horse,” aiming to harness energy from the Kuroshio ocean current that flows from the eastern coast of Taiwan and around the southern parts of Japan.
The initial phase of the project was successful, and the Unit is now searching for industry partners to continue into the next phase. But the OIST researchers also desired an ocean energy source that was cheaper and easier to maintain.
This is where the vigor of the ocean’s waves at the shoreline comes into play. “Particularly in Japan, if you go around the beach you’ll find many tetrapods,” Professor Shintake explains. Tetrapods are concrete structures shaped somewhat like pyramids that are often placed along a coastline to weaken the force of incoming waves and protect the shore from erosion. Similarly, wave breakers are walls built in front of beaches for the same purpose. “Surprisingly, 30% of the seashore in mainland Japan is covered with tetrapods and wave breakers.” Replacing these with “intelligent” tetrapods and wave breakers, Shintake explains, with turbines attached to or near them, would both generate energy as well as help to protect the coasts.
Coral reefs are another type of location with strong breaking waves. Water moving from the deep sea over a shallow reef creates fast jet flows of water. Arrays of small WECs will harness electricity from the vortex flow of breaking waves. The design—dark-colored blades on top of white bodies with thin stems—is visually pleasing, and resembles a flock of birds or group of flowers.
