This paper describes results on direct-methane solid oxide fuel cell (air, LSM-YSZ vertical bar YSZ vertical bar Ni-YSZ, CH4) operation for combined electricity and syngas production. Thermodynamic equilibrium predictions showed that efficient methane conversion to syngas is expected for SOFC operating temperature > 700 degrees C and O-2-/CH4 ratios of I. A simple thermal analysis was used to determine conditions where the cell produces enough heat to self-sustain its operating temperature; relatively low cell voltage and O2-/CH4 ratios > 1 were found to be useful. Fuel cells operated at T approximate to 750 degrees C, V approximate to 0.4 V, and O2-/CH4 approximate to 1.2 yielded electrical power output of similar to 0.7 W cm(-2) and syngas production rates of similar to 20 SCCM cm(-2). Stable cell operation without coking for > 300 h was achieved. (c) 2006 Elsevier B.V. All rights reserved.