A system for generating a high-hydrogen gas comprises a reformer for the catalytic water vapor reforming of a water vapor/fuel mixture while supplying thermal energy; a gas purification stage for removing carbon monoxide from the high-hydrogen gas while releasing heat; and devices for transmitting thermal energy from the gas purification stage into the reformer. The reaction rates in the reformer and in the gas purification stage are designed such that a defined temperature level is set automatically by the coupling of the two reactions.