An energy analysis of three typical solid oxide fuel cell (SOFC) power systems fed by methane is carried out with detailed thermodynamic model. Simple SOFC system, hybrid SOFC-gas turbine (GT) power system, and SOFC-GT-steam turbine (ST) power system are compared. The influences of air ratio and operative pressure on the performance of SOFC power systems are investigated. The net system electric efficiency and cogeneration efficiency of these power systems are given by the calculation model. The results show that internal reforming SOFC power system can achieve an electrical efficiency of more than 49% and a system cogeneration efficiency including waste heat recovery of 77%. For SOFC-GT system, the electrical efficiency and cogeneration efficiency are 61% and 80%, respectively. Although SOFC-GT-ST system is more complicated and has high investment costs, the electrical efficiency of it is close to that of SOFC-GT system. Copyright (c) 2013 John Wiley & Sons, Ltd.