Theproperties of single-chamber solid oxide fuel cells (SC SOFCs) composed of an electrolyte based on yttria-stabilized zirconia (YSZ), a platinum anode, and a strontium-doped lanthanum manganite (LSM) cathode and fed with a methane-air mixture in a temperature range of 500-750 degrees C have been studied. It has been shown that, in the presence of LSM, the methane conversion in the oxidation reaction at 650 degrees C does not exceed 10%; therefore, LSM can be used as a cathode material in SC SOFCs. It has been shown that a Pt vertical bar YSZ vertical bar LSM cell makes it possible to generate electricity. The maximum specific power (36 mW/cm(2)), voltage (0.85 V), and short-circuit current density (132 mA/cm(2)) are achieved at 700 degrees C, a [CH4]/[O-2] ratio of similar to 1.0, and a reaction mixture feed rate of 330 cm(3)/min. The study has shown that it is possible to design SC SOFCs fed with a methane-air mixture, which are capable of generating electrical power. The methane remaining after the operation of SC SOFCs can be used to generate heat or converted to synthesis gas, which is used as a feedstock, for example, in the production of ammonia, methanol, or hydrocarbons by the Fischer-Tropsch process.