Assessment of Tidal Current Resources: Case Studies of Estuarine and Coastal Sites

The potential for tidal stream power in North Western European waters is large and a number of axial flow, vertical rotor and oscillating hydroplane schemes are approaching full scale design and construction. The accurate determination of the available or potential fluid power is being addressed by, in particular, the regulatory bodies as they move towards the establishment of industry standards and the identification and designation of licensing areas. A generic formulation is developed here which utilises Admiralty tidal diamond data and the arithmetic summation of harmonics due to the lunar semi-diurnal, the solar semi-diurnal and (for shallow water and estuarine sites) the lunar quarter diurnal components. Numerical and sensitivity analyses show that the long term potential power is sensitive to the amplitudes of the harmonics but insensitive to the frequencies and phase differences. The results are applied to estuarine sites off Immingham and at Hull Roads in the Humber and to a shallow water, coastal site off Weston-super-Mare in the Bristol Channel. The results indicate that the shore side energy output from a small scale, meso-generation, 100 m 2 capture area device with 60% efficiency varies from about 600 MWha −1 in the Bristol Channel to about 900 MWha −1 in the Humber where the ebb dominated tide flows for longer durations and at slightly higher speeds.