An apparatus for generating energy using sensible heat of an offgas during manufacture of molten iron and a method for generating energy using the same are provided. The method for generating energy includes i) providing an offgas discharged from an apparatus for manufacturing molten iron including a reduction reactor that provides reduced iron that is reduced from iron ore and a melter-gasifier that melts the reduced iron to manufacture molten iron; ii) converting cooling water into high pressure steam by contacting the cooling water with the offgas; and iii) generating energy from at least one steam turbine by supplying the high pressure steam to the steam turbine and rotating the steam turbine.