Tidal Stream Turbines
The simplest way to develop tidal stream energy is to borrow from horizontal axis wind turbines, where the technology, components and know-how have been developed over the last 30 years. A tidal stream turbine is just like a wind turbine underwater, except that the density of seawater is 800 times greater than air, and flow rates typically one fifth. So a properly rated tidal turbine would have a rotor diameter about half that of a wind turbine of the same rated power. The blades, hub and transmission can all be borrowed from wind turbine components, properly sized and marinised for long-term underwater use.
The real problem is supporting the rotor-transmission so that it follows the water flow and can be installed and maintained easily and cheaply. For deepwater sites, where two thirds of the resource lies, submerged floating designs are necessary. These avoid the storm vulnerability of surface floating devices, and the impracticality of seabed-mounting.
The section below will take you through our thinking process to the final design shown on the Home Page.