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Combined wind and wave power device

Green Ocean Energy Ltd has developed a wave power machine which attaches to an offshore wind turbine thereby giving combined wind and wave power from one installation.

The 500 kW Wave Treader has achieved proof of concept and a full size prototype could be ready for testing in 2010.

The Wave Treader has been developed using the core concept of a stand-alone wave power device called Ocean Treader which is also being developed by Green Ocean Energy. Mounting the device on the foundation of an offshore wind turbine is said to make the technology more commercially viable because of the relatively low technical risk.

The Wave Treader comprises sponsons mounted on the end of arms both in front and behind the turbine’s column, which is vertically mounted on the seabed. Hydraulic cylinders are attached between the arms and an interface structure, and as the wave passes along the device the sponsons and arms lift and fall stroking the hydraulic cylinders.

The cylinders pressurise hydraulic fluid which, after smoothing by accumulators, spins hydraulic motors and then electric generators. The electricity is exported back to the shore through the same cables used by the wind turbines.

Wave Treader can turn to face the direction of the wave and it has active on-board adjustments to allow for the effects of tidal range. It has a design life of 25 years.

Green Ocean Energy was able to develop the Wave Treader technology after securing £60,000 of funding from npower’s Juice fund – a scheme that supports the development of wave and tidal technology.

Helen Steed of npower’s Juice fund comments: “The device is the first of its kind, and shows tremendous potential in utilising existing off-shore infrastructure to generate clean renewable energy.”

To date npower Juice fund has invested £2 million into the development of marine renewable industry.

Green Ocean Energy is now looking to attract further investment to enable continual development of the company’s products.

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Wave and tidal energy  •  Wind power