At the present time, the role of renewable energy in Brazil is significant as hydropower and other renewable energies, principally biomass, contribute 76.9 and 6.0 %, respectively, towards the total offer of electricity, as compared to the corresponding values of 15.8 and 2.8 % worldwide. Nevertheless, there is already an increasing role which is played by wind energy, and a promising potential for the exploitation of tidal current energy. This paper is concerned with the assessment of the tidal current resource in São Marcos Bay, which is located at the northeastern coast of Brazil, and which possesses a highly promising potential for the generation of electricity through the conversion of tidal current energy. Three potential zones for tidal power exploitation have been identified employing a two-dimensional (2DH) hydrodynamic model. Power densities for these regions are in the range of 9.2–11.2 MWh/m\(^{2}\)-year. Three array densities for two thrust coefficient values have been studied in each zone to evaluate hydrodynamic interferences, revealing positive as well as negative impacts regarding power density.