A thermodynamic and electrochemical framework transformed into an electrical network is used to analyze the power output and efficiency of high-temperature, ceramic fuel cell heat engine systems for the hydrogen oxidation reaction. It is interesting that the heat engine combustor subsystem performance was able to be recast in electrochemical and electrical network terms. The analysis includes the effect of temperature on the operation and performance of these ceramic, high-temperature systems. The power and efficiency responses of a distributed energy system operated at constant voltage to protect the fuel cell, using supplemental firing of the heat engine, and subjected to a cyclic load demand is presented. These systems are of interest to the emerging renewable energy grid. While the perfect fuel cell would undergo no degradation, practical fuel cells will degrade. The partition of power in a degrading distributed energy system is examined.