A review of methods for determining average available power from a tidal current

The use of in-stream tidal energy conversion devices is gaining popularity as a potential energy source. Methods discussed for determining the average available power from a tidal current include; kinetic energy calculations, one dimensional (1D) analytic models derived from Bernoulli´s theorem and the Navier-Stokes equations, and the use of two dimensional (2D) numerical models of ocean flow. The kinetic approach may be used to provide an estimate of available power provided the ratio of TEC capture area to channel cross-section is much less than one; 1D analytic models demonstrate that tidal power resource assessments must not be based solely on the natural undisturbed flow state, the relationship between flow speed, frictional losses, and extracted power must be considered to determine a maximum available power; and 2D numerical models are necessary to allow for flow diversion around arrays of TEC devices and to evaluate the far field effects of energy extraction.