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NEDO Develops Counter-Rotating Propeller Technology for Tidal Stream Power Generation
– Power generation performance and safety evaluated in actual sea environment through towing test –

November 17, 2017
New Energy and Industrial Technology Development Organization (NEDO)
Kyowa Engineering Consultants Co., Ltd.
EIM Electric Co., Ltd.
Maeda Corporation
Kyushu Institute of Technology
Waseda University

NEDO, together with Kyowa Engineering Consultants Co., Ltd., EIM Electric Co., Ltd., Maeda Corporation, the Kyushu Institute of Technology, and Waseda University, has developed a counter-rotating propeller technology for tidal stream power generation. The propeller technology has been developed to serve as an element technology for the next-generation of ocean energy power generation.

After developing the concept of a power generator and simulating a tank test, using a 1/7 scale model of the projected practical machine (propeller diameter of 7m; output 500 kW when the flow rate is 4m/s) a towing test was conducted from October 17 to 20 off the coast of Nagasaki Bay. The towing test evaluated the power generation performance and the safety. It confirmed a power generation efficiency of 43.1%, which exceeded the power generation efficiency estimate based on the design.

This power generation technology is characterized by its adoption of a counter-rotating method, which generates power by using two-stage propellers rotating in opposite directions. It is expected to have higher power generation efficiency than a conventional one-stage propeller system. The size of the device can also be smaller for the same amount of power generation.

  • Image of the 1/7 scale model of the projected practical machine
    Figure 1 A 1/7 scale model
  • Image of the tug boat conducting a test at sea
    Figure 2  The towing test

For more information, please contact:

NEDO New Energy Technology Department
Contact Persons: Hamamoto, Tamura Tel: +81-44-520-5273­

Kyowa Engineering Consultants Co., Ltd.
Advanced Project Team
Contact Person: Samura Tel: +81-3-3376-3170­