Flow turbulence stands out as one of the main issues that must be addressed for tidal stream energy to become a fully-fledged renewable energy source. In this context, the present paper studies the impacts on the turbulence conditions derived from the operation of a tidal energy farm. For this purpose, a 3D hydrodynamic model was implemented for the Orkney region (N Scotland), which was validated against field data of tidal flow velocity and turbulence kinetic energy (TKE).After validation, the model was used to assess the impacts on the TKE for a complete tidal cycle. The results obtained highlight the remarkable effects of tidal stream exploitation in the turbulence conditions, especially at the deepest layers of the water column, with differences up to 50 % with respect to the undisturbed conditions. Therefore, these important modifications in the turbulence conditions may increase the fatigue and loads on the mooring and supporting structures of the tidal turbines and also impact other relevant coastal processes such as pollutant and nutrient transport.