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IHI unveils prototype 'ocean energy' generator

The prototype of the ocean current power generator developed by IHI Corp. and the New Energy and Industrial Technology Development Organization is seen in Yokohama, on July 7, 2017. (Mainichi)

As the world considers alternative ways of generating energy, engineering giant IHI Corp. on July 7 unveiled an "ocean current power generator" prototype.

    The device, which harnesses ocean energy using currents found in oceans, will be tested in a demonstration experiment off the coast of Kuchinoshima, an island in Kagoshima Prefecture. It follows an experiment relating to wave-power generation that Mitsui Engineering and Shipbuilding Co. announced in April.

    Given Japan's lack of energy resources, the emergence of alternative-energy projects such as these ones carried out by IHI and Mitsui are gaining attention.

    In the case of IHI, the ocean-driven machinery consists of propellers in the sea that are rotated by ocean currents, which in turn move turbines that generate power. It is a reliable form of energy as the fairly constant speed and direction of ocean currents means that energy can be generated throughout the year. Ocean energy differs considerably to other forms of renewable energy such as solar and wind power, which are both heavily dependent on climate.

    Since fiscal 2011, IHI has collaborated with the New Energy and Industrial Technology Development Organization (NEDO) to harness the energy of ocean currents, and together they came up with the prototype. In mid-August the prototype is set to be used in the world's first verification test in Kagoshima Prefecture.

    The machine, unveiled on July 7 in Yokohama, consists of two tubular generators about 20 meters long with two propellers, about 11 meters in diameter, attached to them, along with a transformer. The generated power is carried through a cable on the sea bed to a power receiving facility, with a power generation capacity of 100 kilowatts.

    IHI aims to turn its prototype into an actual product by 2020. The company wants each generator to produce 2,000 kilowatts of energy, enough to provide 3,000 homes with power. Shigeki Nagaya, a director at IHI, says, "We're not just thinking about selling this device, but also believe that a business model based on ocean power generation is possible."

    However, while the concept sounds impressive, there are some issues that need to be addressed. First, the cost of the equipment is very high. Nagaya explains that the current prototype is "too expensive to be compared" to solar power and wind power, which cost between 20 to 40 yen per kilowatt-hour. In addition, to put a product on the market, it is also necessary to assess the possible effect on ecosystems, and also coordinate with local communities about issues such as fishing rights.

    It remains unknown whether the project can be a successful business as "ocean energy" has never been commercialized before. IHI manager Akio Ito says, "First, our priority is to succeed in our prototype experiment, and gain recognition in society."

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