Japan Develops Unique Wave-Catching Turbines to Harvest Power

Researchers with the Okinawa Institute of Science and Technology are solving two problems at one time by creating a unique wave turbine. The turbine both captures wave power and can help save shorelines from heavy wave erosion.
Shelby Rogers
Strong breaking waves can be found along coral reefs. This mockup of the turbines along a reef could be the future of Japan's wave energy.OIST

A team of researchers from the Okinawa Institute of Science and Technology just make a unique innovation that could revolutionize water power. The OIST developed a system that not only harnesses energy from crashing waves, it also dissipates the impact of the waves and could help save coastlines around the world.  

Wave energy provides coastal areas with seemingly endless energy. From Hawaii to Gibraltar to the Californian coast, environmental scientists are developing ways to harness the power of water. However, that power can also be destructive when it comes to wave erosion along populated coastal areas. Professor Tsumoru Shintake and the Quantum Wave Microscopy Unit at OIST started the "Sea Horse" project to try and take advantage of both wave power and reduce overall erosion along Japan's coast. 

Japan Develops Unique Wave-Catching Turbines to Harvest Power
The final diameter of the turbine is expected to be 0.7 meters. The axis is attached to a magnet electric generator. This particular design is expected to function for 10 years before needing replacement. Source: OIST

The project began with submerged turbines to convert the kinetic energy of the natural currents into electricity. That energy is delivered by cables to inland areas as well. Shintake noticed a considerable number of tetrapods along the coastline. Tetrapods are triangular structures that weaken the force of waves to protect a shore from erosion.  

"Particularly in Japan, if you go around the beach you'll find many tetrapods," Professor Shintake explained. "Surprisingly, 30 percent of the seashore in mainland Japan is covered with tetrapods and wave breakers."

So, Shintake and his team decided to upgrade "Sea Horse" to take advantage of tetrapods. Shintake said that by putting turbines next to or attached to a tetrapod, the team would ultimately do more good. 

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"Using just 1 percent of the seashore of mainland Japan can [generate] about 10 gigawats [of energy], which is equivalent to 10 nuclear power plants," Shintake noted in a press release. "That's huge."

Thus, the Wave Energy Converter (WEC) project was born. Each turbine is positioned to experience the ideal wave conditions near coral reef systems or along preexisting tetrapods to generate energy. They're anchored to the sea with mooring cables. The turbines will 'peek' above the sea level at the proper height to catch most of the wave's energy. After more than three years of testing and trials, the team has finished the first step of the project. They're prepping for installation fo half-scale model turbines with a diameter of 0.35 meters for a commercial experiment. 

Blades inspired by dolphin fins

The OIST team made the turbines capable of withstanding nearly any force imaginable, including during extreme weather like typhoons. The flexible blades are modeled after dolphin fins. The cartilage-esque build means they're able to release stress rather than break under pressure. Shintake compares the back of the structure to a flower.  

"The stem of a flower bends back against the wind," he said, noting that the turbines will also bend along the anchoring axes. The team also reported that the turbines were designed with oceanic wildlife in mind. The blades rotate at such speeds to give anything caught around them time to get out of the way. 

Shintake said he hopes the project outlasts him and can serve as a legacy for the team.

"I’m imagining the planet two hundred years later," Shintake said. "I hope these [turbines] will be working hard quietly, and nicely, on each beach on which they have been installed."