KW Stingray

In 2002 a 150 kW demonstrator device was designed, built and installed at Yell Sound in Shetland by the Engineering Business Ltd. The power take off mechanism consisted of four opposing hydraulic rams used to drive oil around a hydraulic circuit, via a hydraulic motor coupled to a rotary generator. It is possible to apply a variety of different control strategies in an attempt to maximise the power taken from the channel. For example, two features which may be controlled are the hydroplane angle of attack and the phase, shape and magnitude of the power take off force. The upper limit of extracted power will be dictated by the 59% Betz limit when considering the entire area swept by the hydroplane. Currently it is primarily the concept of tidal stream generation that is being investigated and there is no research programme in altering the present hydraulic take off mechanism. The direct drive concept is likely to be considered later in the Engineering Business development programme, in the region of 5-10 years from now [93].

Figure 7.1: Photograph of 150 kW prototype shortly before deployment

Figure 7.1 shows a photograph of the prototype as it was being assembled in Summer 2002. For this investigation the movement of the arm is assumed to extend 30° above and below the horizontal in a purely sinusoidal manner with a period of 21 seconds. The hydrofoils will oscillate between 5 and 17 m above the seabed, which is a typical cycle for a water velocity of 1.5 m/s. The speed and motion may be controlled to maximise the power captured by the device.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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