Several models have been proposed to address the operating characteristics of tubular solid oxide fuel cells (SOFC). A discussion covers modeling work and the validation of a model on a commercial SOFC; physical phenomena that occur in a cell; momentum conservation equations; calculation errors; modeling of oxygen ion conduction; full cell model of SOFC developed considering all the significant physical phenomena that play a critical role in determining the resultant power-density of the system; and the predictive capability of the model. This is an abstract of a paper presented at the 2006 AIChE Annual Meeting (San Francisco, CA 11/12-17/2006).