TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The nanotubes comprise carbon nanotubes having a total surface area greater than 1000 m2/g. The carbon nanotubes comprise single walled nanotubes (SWNTs) having a total surface area of 1000-1587 m2/g. The hydrocarbon fuel is methane and natural gas; and the fuel cells comprise solid oxide fuel cells. The nanotubes contain a hydrocarbon fuel absorbed or adsorbed to the nanotubes. The inventive system further comprises a heating device adapted to heat the storage device to desorb the hydrocarbon fuel from the nanotubes in the storage device. The heating device comprises a heat transfer device adapted to transfer heat from the fuel cell stack to the storage device. The inventive system further includes a pressurization device adapted to lower a pressure in the storage device to desorb the hydrocarbon fuel from the nanotubes in the storage device and to raise the pressure in the storage device to adsorb the hydrocarbon fuel to the nanotubes. It has a fuel cell stack containing fuel cells; first mechanism for storing a hydrocarbon fuel; and second mechanism for providing the hydrocarbon fuel from the first mechanism to the fuel cell stack. Preferred Methods: The operation of the fuel cell system comprises heating the nanotubes to desorb the hydrocarbon fuel from the nanotubes prior to providing the hydrocarbon fuel from the nanotubes to the fuel cell stack. Heating comprises transferring heat from the fuel cell stack to the nanotubes. The operation method further comprises lowering the temperature of the nanotubes and providing hydrocarbon gas to the nanotubes to store the hydrocarbon fuel in the nanotubes. It includes lowering a pressure of the nanotubes to desorb the hydrocarbon fuel from the nanotubes prior to providing the hydrocarbon fuel from the nanotubes to the fuel cell stack; and raising the pressure of the nanotubes and providing a hydrocarbon gas to the nanotubes to adsorb the hydrocarbon gas to the nanotubes.