In present discussions on energy conversion processes aimed at producing both thermal and process heat, catalytic burners provide an alternative approach for future applications. Catalytic burners are advantageous in that they cause only low pollutant emissions during the process of converting chemical energy into heat. In addition, novel engineering concepts require the complete combustion of a variety of fuels and fuel mixtures. Against this background a novel catalytic radiant burner was developed at the Research Centre Julich. Under near-stoichiometric conditions, this catalytic burner bums both natural gas with hydrogen admixture in a heat recovery boiler for stationary heat production and methanol with hydrogen admixture in a reformer producing process heat to be used in a fuel cell drive system. The emission data of the catalytic heater were recorded at a nominal power of 11.5 kW, a nominal air/fuel ratio of 1.15 and different hydrogen ratios between 0% and 50% and were 7-3 mg/kW h for carbon monoxide and 3.3-3.9 mg/kW h for nitrogen oxides. The test runs for a catalytic burner to be used for heating a compact reformer in a fuel cell vehicle were carried out at a power density of 15-60 kW/m(2), a nominal air/fuel ratio of 1.1 and different hydrogen, carbon dioxide and water ratios. For nitrogen oxides emissions of less than 0.4 mg/kW h, the measured carbon monoxide amount ranges between 0 and 13 mg/kW h.