A power supply includes a fuel cell stack, a thermoelectric module and a burner module. The fuel cell stack generates a primary source of electricity and secondary source of heat. The thermoelectric module generates a secondary source of electricity. The burner module is juxtaposed to the fuel cell stack and the thermoelectric module, to provide primary heat to the system and to generate a temperature differential across the thermoelectric module, and to pre-heat a fuel and an oxidant for the fuel cell stack. The burner module is regulated to maintain a given system temperature, or when needed by the thermoelectric generator for secondary power generation.