Abstract: The invention relates a method for operating a high-temperature fuel cell installation having a high-temperature fuel cell module. The method includes the step of producing a combustion gas having a combustion gas power for an electrochemical reaction in a high-temperature fuel cell module by a reformation process using a heat content from the electrochemical reaction in the high-temperature fuel cell module for reforming the combustion gas. The method includes the step of producing excess hydrogen that is not consumed during the electrochemical reaction in the high-temperature fuel cell module. There is the step of operating cells of the high-temperature fuel cell module with a cell voltage of less than about 0.7 V. Finally, there is the step of storing the excess hydrogen that was not consumed in the electrochemical reaction outside of the high-temperature fuel cell module. In this manner, one optimizes the effectiveness of the high-temperature fuel cell installation.