The power generation changes from conventional to renewable generators resulting in new challenges for the grid operators. One important aspect is reserve power. Due to fluctuating resources as wind and photovoltaics, the need for reserve power even increases. In this paper, it is studied, how tidal energy conversion systems can be controlled providing primary response. Thereby, the rotor speed is an important control parameter varying the power output for a given tidal current velocity as desired. A network model is proposed containing a synchronous motor load for testing the tidal turbine influence on the grid. Simulation is carried out in Matlab/Simulink. The results validate the proposed control for primary response.