FIELD: hydroelectric power plants. SUBSTANCE: invention relates to the structures of autonomous tidal damless tidal hydroelectric power plants. The hydroelectric power plant contains a cylindrical tank 1 and a storage tank 2, connected at the upper level by a pipeline 3, at the lower level by a pipeline 4 for water drain, equipped with a check-off valve 5. At the base of the tank 1, there is a bi-directional Welsh turbine 6, which is kinematically connected to the generator 7. The pipeline 4 is located above the hydraulic turbine 6. The tank 1 has an opening 8 for water inlet, located at a level below the hydraulic turbine 6, and an opening 9 for air outlet in its upper part. At the upper tide level, an additional water reservoir 10 is introduced, the inlet 11 of which is equipped with a check valve 12, and the outlet 13 is connected by a pipe 14 with the lower additional opening 15 of the tank 1. The opening 8 has a spring-loaded closing valve 16, connected by a flexible rod 17 with a loaded additional load with a float 19 installed in the tank 10 on a height-adjustable stop 21. EFFECT: creation of a small-sized damless tidal hydroelectric power plant. 1 cl, 1 dwg.