An ocean wave and tidal current energy conversion system includes a first vessel and a second vessel, the first vessel being parallel and spaced apart from the second vessel. The first and second vessels include supports that receive cylinders that rotate from ocean waves and currents to create hydraulic oil pressure via hydraulic cylinders. The hydraulic oil in the energy conversion system is pumped into a pressure accumulator that removes hydraulic surges and operates an electric generator. The electric generator may power an electrolysis batch system for the production of hydrogen that fills each vessel with hydrogen gas.