The extractable power from a channel linking a bay to the open ocean

TLDR

Interest in tidal‑stream power is growing worldwide, yet current Canadian estimates (~42 GW) based on average kinetic energy flux fail to capture the maximum extractable power for electricity generation. This work presents an updated theory for the extractable power from a tidal stream in a channel linking a bay to the open ocean. The authors develop a theory that models the channel as a tidal stream linking a bay to the open ocean, deriving an expression for maximum extractable power. The maximum average extractable power from such a channel may be estimated, within ~15 %, as 0.22 ρ g a Q₀, where a is the amplitude of the dominant tidal constituent in the open ocean and Q₀ is the maximum volumetric flowrate in the undisturbed state.

Abstract

Interest in the power potential of tidal streams is growing worldwide. While the latest assessment for Canadian coastlines estimates a resource of approximately 42 GW, these results are based on the average kinetic energy flux through the channel. It has been shown, however, that this method cannot be used to obtain the maximum extractable power for electricity generation. This work presents an updated theory for the extractable power from a tidal stream in a channel linking a bay to the open ocean. The maximum average extractable power from a channel linking a bay to the open ocean may be estimated, within approximately 15 per cent, as 0.22ρ gaQ 0 , where a is the amplitude of the dominant tidal constituent in the open ocean and Q 0 is the maximum volumetric flowrate in the undisturbed state.