Disclosed is an MCFC power generation system and a method for operating the same enabling significant reduction of CO 2 emission or substantially zero CO 2 emission by minimizing the equipment added to a general power generation facility to a minimum, enabling both high power generation efficiency and high heat recovery efficiency, enabling adjustment of the voltage and output of the fuel cell in a certain range by adjusting the cathode gas composition, enabling great variation of the ratio between the heat and electricity, and thereby enabling variable thermoelectric operation. The MCFC generation system includes a cathode gas circulation system in which the cathode gas is circulated by a cathode gas recycle blower, and a closed loop is formed. Oxygen consumed by power generation is supplied from an oxygen supply plant, and CO 2 is supplied from recycled CO 2 . Combustible components in anode exhaust are burned with oxygen, the resultant gas is cooled, and water is removed. The fuel gases in the anode exhaust is recycled.
