MODEC Inc exhibited a mock-up of a floating wind/tidal hybrid power generation system that the company is preparing to test.
The mock-up of the system, "skwid," was shown at Wind Expo 2013, which runs from Feb 27 to March 1, 2013, in Tokyo. The system is made by combining a Darrieus windmill whose blades erect and a Savonius waterwheel that rotates always in the same direction regardless of the direction of tidal current.
"It is more cost competitive than any other floating wind power generation systems," MODEC said.
The amount of power generated by a Darrieus windmill is twice as large as that of a propeller windmill, which is commonly used for wind power generation systems installed on land, when they have the same diameter because a Darrieus windmill has a larger swept area. Also, because of its low center of gravity, it is stable on the water.
MODEC used a Savonius waterwheel made by combining vertically-split cylinders so that it can fully utilize slow tidal currents. Because the Darrieus windmill and the Savonius waterwheel are both connected to a generator installed in the center of the floating system, power can be generated by using wind and tidal current.
MODEC has been manufacturing a hybrid power generation system with an output of about 500kW for a field test. And it has already made all the units for the system. The company plans to test the units on land and, then, the entire system on the sea within 2013.