Energy integrated fuel cell systems show the potential for highly efficient and enviromentally friendly power generation. In this study, an energy integrated system with a solid oxide fuel cell (SOFC) and a methane steam reformer is considered. The effect of the reformer design parameters (steam-to-carbon (S/C) ratio and operating temperature) on the steady-state performance of the entire SOFC system is studied. Additionally, the effect of the S/C ratio on the open-loop behavior is also analyzed under small and large steps in the current. Lastly, the closed-loop performance of the entire energy system for a decentralized control scheme is evaluated under a large disturbance in load current.