POWER GENERATION SYSTEM

PROBLEM TO BE SOLVED: To provide a power generation system capable of efficient generation independently of a region whereas a geothermal power generation system is available only in geothermal regions.SOLUTION: The power generation system includes: a generator for generating power by a turbine to which motive power is applied by energy of a working medium heated by a heat pump including a compressor; a circulating means for sending the working medium from the turbine; and a control unit. The working medium includes an organic compound with an absolute pressure of saturated steam pressure at 90°C of 0.3 MPa or higher, makes COserve as the coolant, and a scroll turbine or a screw turbine as the turbine, keeps working medium pressure at a turbine inlet equal to or less than the saturated steam pressure of the working medium at a temperature of the turbine inlet, so that total power equal to a sum of compressor driving power, circulating means driving power and control unit power for the control unit is supplied to enables the system to be driven under such conditions that generated power is predetermined to be larger than the total power. In an unsteady state, the generator is driven as a motor, and the turbine is used as a circulating means for the non-steady state.