COMBINED POWER GENERATION SYSTEM AND DRIVING METHOD THEREOF

A combined power generation system (101, 102, 103, 104) includes a gas turbine (20), a heat recovery steam generator (50) (HRSG) generating steam using combustion gas from the gas turbine (20), a vaporizer (73) vaporizing liquefied ammonia, an ammonia decomposer section (30) decomposing ammonia with the combustion gas, a first exhaust gas line (27) through which exhaust gas from the gas turbine (20) is transferred to the HRSG (50), a steam turbine (40) generating a rotational force with the steam from the HRSG (50), a decomposed gas supply line (34) through which decomposed gases generated in the ammonia decomposer section (30) are supplied to a combustor (23), and a cold heat transfer line (62) absorbing cold heat of the liquefied ammonia and supply the cold heat to the condenser section (60), and a condenser section (60) condensing the steam from the steam turbine (20).