In this Doctoral Thesis several factors involved in the use of tidal energy in the Ría de Ortigueira are studied, including the determination of the most appropriate conversion system, based on the analysis of annual yields and their intra-annual variability, and the impacts derived from energy use on transient and residual circulations. For this purpose, a 3D high-resolution numerical model is implemented for simulate the hydrodynamics of the estuary during different periods, with different combinations of boundary conditions and different tidal power plants. The results achieved allow to continue advancing in the research and development of renewable energies in Galicia, more specifically, marine renewable energies, which have great potential in this territory due to its privileged location in the South Atlantic Region of Europe.