Ocean currents are generated from the forces acting upon the water like the earth's rotation, the wind, the temperature, salinity differences and the gravitation of the moon. The depth contours, the shoreline and the temperature influence the current's direction and strength. The estimated total power in ocean currents is about 5,000 GW, whereas power density may be up to 15kW/m2. Power can be extracted from the ocean current using a horizontal or a vertical axis turbine.
Vertical axis turbines will produce electricity from water, regardless of the direction of the flow. This research proposes a hybrid turbine that has a much better self-starting behaviour. This paper presents the design of a hybrid turbine based on a straight bladed darrieus (Lift type) turbine along with a double step savonius (Drag type) turbine. The hybrid turbine will be used to generate power at the sea-floor for an instrumentation system.
