Modelling assessment of the tidal stream resource in the Ria of Ferrol (NW Spain) using a year-long simulation

The availability of tidal stream energy in the Ría of Ferrol (NW Spain) has been assessed using a long term hydrodynamic simulation (351 days). A priori, a strait in the central part of the estuary seems a promising site for tidal energy tapping, but the results show that barotropic currents rarely exceed 0.9 m/s during spring tides, with a maximum peak power density of 0.45 kW/m2 estimated at a spring tide mid-ebb. The maximum annual energy density is estimated at 415 kWh/m2, significantly lower than at other nearby estuaries. A comparison of the annual resource estimates shows that differences of up to 35% can be introduced depending on whether a simulation of one tidal cycle, one lunar month, or a full year is used for the calculations. This proves that usual tidal resource estimations, based on a single tidal cycle, can significantly misestimate the tidal energy potential of a site.