Assessment of tidal stream energy resources in a hypertidal estuary with highly irregular bathymetry using 3D numerical modelling

Abstract

Owing to large currents generated by the strong tides coming from Ungava Bay, the hydrokinetic energy potential of the Koksoak River Estuary (KRE) Nunavik, Canada, is substantial. With a tidal range of more than 12 m, the KRE is classified as “hypertidal”, and with water depths ranging from 10 to 130 m and widths ranging from 700 to 4500 m, it could also be said that the KRE is “hyperbathymetric”. Even aside from the intense cold associated with its Arctic climate, this combination of hypertidal/hyperbathymetric makes the KRE possibly the most extreme estuary in the world. Using a 3D hydrodynamic finite-difference model to simulate the KRE’s velocities, the in-stream power densities were calculated over the entire domain. The resulting map pinpoints the energy sites available for the 3000 residents of Kuujjuaq, a town located 50 km from the estuary mouth. At optimal KRE sites, based on vertically averaged velocities, the available mean power density is 7.2 kW/m2. Near the surface, the available mean power density increases to 10.5 kW/m2. These values exceed that calculated (6.0 kW/m2) for the famous Bay of Fundy’s Minas Passage. This paper describes the nature of the estuary, introduces the modelling efforts, and quantifies the spatial–temporal variability of the available hydrokinetic power density.