A power generation system includes: a power generation unit configured to discharge a flue gas; a housing configured to accommodate the power generation unit; a ventilator configured to ventilate the housing; a first gas channel through which a gas discharged from the ventilator flows; a second gas channel through which the flue gas from the power generation unit flows; a merging portion where the first gas channel and the second gas channel merge; a third gas channel through which the gases merged at the merging portion flow; a water trap unit connected to the first gas channel and including a water sealing structure; and a water discharge channel through which water in the water trap unit is discharged to an outside of the housing.