The TEGs referred to in this report consist of an array of thermocouple elements heated on one face by a self-contained burner and cooled on the other face by air or a liquid-to-air system. The thermocouple elements are typically semiconductor material, and they develop a voltage proportional to the temperature differential maintained across them and an available current that is proportional to the heat flow. Fuel cells consist of a two-stage system in which fuel is first processed into hydrogen and then fed, together with air, to a cell stack. In the cell stack, hydrogen releases electrons in reaction with the oxygen (from the air) thus creating water and a flow of electrons. The cell stack collects the electrons liberated in the reaction and delivers the electrical energy to the external circuit or load.