By TAKAHIRO TAKENOUCHI/ Staff Writer
March 5, 2020 at 07:00 JST
ISHIGAKI, Okinawa Prefecture--A bladeless wind turbine that can withstand the fiercest typhoon. The concept is a godsend to those who champion alternative sources of energy.
An enterprising engineer designed just such a device in the aftermath of the 2011 nuclear disaster, figuring that Japan "would be finished" energy-wise if it was hit by another nuclear catastrophe.
Atsushi Shimizu, 40, figured his invention will help Japan wean itself from nuclear power generation altogether.
Another advantage is that his system is entirely safe.
Shimizu was working for a leading manufacturer of sensors when the earthquake and tsunami disaster hit, triggering a triple meltdown at the Fukushima No. 1 nuclear power plant.
It was then that he floated his concept of a new style of wind turbine as an energy source.
He examined 5,000 patents involving wind power generation and hit upon the idea of a design that did not rely on turbine blades, which can break in very strong winds, but a device comprising cylindrical components.
He applied for a patent in June 2011, and built a scale model which he placed in front of an electric fan to simulate wind.
His patent was approved in 2013, and Shimizu quit his company to establish a Tokyo-based startup called Challenergy to pursue his dream.
The beauty of his design is that the 20-meter-tall windmill rotates each cylindrical part with electricity. Then the entire turbine rotates when wind gathers strength.
“Wind farms have not taken off in Japan due to the difficulty of adjusting the direction of the turbine blades when the wind rapidly changes direction,” Shimizu said. “The propeller structure is also the weak point in power generation because the blades can break in strong winds."
Wind turbines typically have to stop operating in winds of around 90 kph. At these speeds, blades rotate at an extremely fast pace and can easily snap.
However, his vertical-axis Magnus model can stop its turbine simply by cutting the power supply to the cylinders. It can operate in winds of up to 144 kph and withstand gusts as high as 252 kph.
Shimizu's innovative windmill is undergoing trial tests on Ishigakijima, an island in Okinawa Prefecture famed for its sandy beaches and turquoise waters. During the course of a year, he reckons it can generate enough electricity to meet the annual needs of four or five ordinary households.
The system will be commercially available by the end of the year, with a price tag in excess of 20 million yen (181,700). The company said it has already received inquiries from communications and other businesses.
To confirm whether his brainchild can withstand a typhoon, Shimizu began testing it in 2016 in Nanjo, southern Okinawa Prefecture, which is frequently buffeted by strong typhoons.
It passed with flying colors during a typhoon in October 2017 that generated wind speeds of 118.8 kph.
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Challenergy Inc.’s 10-kilowatt vertical-axis Magnus turbine (Provided by Challenergy Inc.)
