Recent Patents on Tidal Power Extraction Devices

The patents presented in this paper relate to power generating apparatus suitable for use in extracting energy from the movement of water, particularly tidal movement. This type of energy is generated by the relative motion of the Earth, Sun and the Moon, which interact via gravitational forces. Periodic changes of water levels, and associated tidal currents, are due to the gravitational attraction by the Sun and Moon. Tidal power generating systems have been studied for a number of years both in the form of barrages (similar to conventional hydroelectric dams in that the power extraction depends on the hydrostatic head), as well as tidal devices which exploit directly the kinetic energy of tidal streams. Modern advances in turbine technology may eventually see large amounts of power generated from the ocean, more precisely tidal currents, which is covered by the more general term “marine current power”. The work starts by examining the role played by Computational Fluid Dynamics in the prediction of the flow in these devices. In addition it reviews some recent and important patents relevant to this type of tidal devices, highlighting the significance and limitations of the patents reviewed. The paper concludes by highlighting current and future developments in the field.