Tidal Power from Rectangular Estuaries: Tidal Dynamics Constraints

A one-dimensional analytical model of frictional tidal flow in rectangular uniform section estuaries is presented. The response of different lengths of estuary to given tidal forcing at the mouth is explored to obtain resonance curves, and the linearized friction coefficient appropriate to different tidal amplitudes is indicated. A permeable, energy extracting barrier is introduced and the optimum head/flow ratio is determined for maximum power generation with an ebb/flood operating scheme. Pumped energy storage is introduced by allowing for a complex head/flow ratio and the maximum available net power at optimum design condition is shown to be very much greater than without pumping. The mouth is shown to be the best location. The energy available under various operating constraints, from estuaries of different lengths, is compared with the original energy dissipation in the estuaries. Finally the critical dependence of power output on the choice of barrier flow condition is explored.