METHOD FOR OPERATING INDIRECT INTERNAL REFORMING SOLID OXIDE FUEL CELL SYSTEM

Provided is a method for operating an indirect internal reforming SOFC system, in which the temperature of a reformer can be maintained stably and suitably. A method for operating an indirect internal reforming solid oxide fuel cell system including a reformer including a reforming catalyst layer, for producing a reformed gas from a hydrocarbon-based fuel, a solid oxide fuel cell for generating electric power using the reformed gas obtained in the reformer, and a combustion region for combusting an anode off-gas discharged from the solid oxide fuel cell, wherein the reformer is disposed at a position where the reformer can receive combustion heat generated in the combustion region, the method including the step of controlling the temperature of the reforming catalyst layer by changing the electric power generation output value of the solid oxide fuel cell.