The marine hydropower system proposed in this study uses a seawater exchange type breakwater, which has empty space like a basin to store ocean water in it, as a tidal jet generator. Due to the water level difference between the inner and outer sides of the breakwater, strong and uni-directional jets are generated and the energy from the jets are gained by putting turbines in the ducts of the breakwater
In this study, the proposed system is introduced at first. Then, the results of numerical simulations to predict the efficiency of newly designed hydropower turbine for the system are presented. The performances of the turbine were estimated under the open water and duct conditions. It was confirmed the estimated power could be generated by using the developed turbine.