As is well known, the increasing energy demand requires an efficient use of conventional energy sources, as well as the development of renewable technologies. The distributed generation systems entail significant benefits in terms of efficiency, emission reduction, availability and economy consequences. Renewable energy technologies are fed by intermittent resources. This feature makes the energy storage an important issue in order to improve the management or to enlarge annual operation of the facility. The use of hydrogen as an energy vector may satisfy this requirement and; at the same time, it introduces additional advantages in terms of energy efficiency and emissions reduction. This work presents an analysis based on the first and second thermodynamics law to investigate the efficiency of a hydrogen/oxygen-fueled gas turbine, which produces both electrical and thermal energy (cogeneration). A 20 kWe, microgas turbine is proposed to supply the base load demand of a residential area. The results show that the proposed facility is appropriate when the thermal energy demand is significant. We obtain an exergy efficiency of 45.7% and an energy efficiency of 89.4% regarding the lower heating value (LHV) of hydrogen. This high energy efficiency remains on the use of the liquid water effluent and the condensation heat. The main sources of irreversibility are analyzed and the effect of the design parameters on the energy and exergy efficiencies is discussed.