A hybrid energy system consists of a combination of two or more energy generation technologies to make the best use of their operational characteristics and to obtain higher efficiencies than could be obtained from a single source of energy. Since fuel cells directly transform fuel and an oxidant into electricity through an electrochemical process, they produce very low emissions and have higher operating efficiencies. Therefore, by combining fuel cells with other sources, the efficiency of the combined system can be further increased or extend the duration of the available power to the load as standby power. In this paper we present different types of hybrid fuel cell systems and their applications. An analysis of the combined cycle operation of a solid oxide fuel cell (SOFC) -micro-turbine is presented. A strategy is proposed to combine the thermo-photovoltaic power generation unit and SOFC to obtain the hybrid energy system that would have greater efficiency.