A number of installations integrating high temperature fuel cells with a gas turbine have been proposed. By nature, these are systems whose power depends on the power of the available solid oxide cells. Therefore, these are low-power hybrid installations that can be used in distributed systems of electricity and heat generation, as power supply units for public buildings or as backup power units. They can also be modules of more complex installations, integrated with hydrogen production systems, powered from various sources. The literature analyzes the characteristics of both hydrogen and natural gas systems with internal or external reforming. The article analyzes various technological structures of installation of hierarchical high-temperature cells with a gas turbine, including cogeneration systems. The production efficiency, optimal power ratio of the cell and gas turbine as well as the heat to power ratio were compared. The analysis was carried out for various degrees of fuel conversion in the fuel cell. In addition, the optimum levels of pressures in the gas cycle and the optimal values of the fluid streams were determined. Energy indicators were compared in the models selected for detailed analysis. The selected models differed, inter alia, in the way the unburned fuel from the fuel cell was used. In the analyzes, attention was drawn to technical limitations related to heat exchange, pressure drops and temperature levels in individual elements of the system. The summary compares the energy indicators of the analyzed models with theoretical values and compares the advantages and disadvantages of individual configurations.