A model for simulating a solid oxide fuel cell (SOFC) stack is presented based on efficient numerical algorithms. This approach reduces the computational cost significantly while maintaining a sufficient accuracy of the solution. The single cell SOFC model can be used to optimize the electrode microstructure and geometry of the cell. In the case of direct internal reforming in anode supported cell, optimal anode thickness can be found for a given inlet fuel composition. The model also predicts the optimal catalyst loading required for a given inlet fuel composition. This single cell model was used to study the optimal performance of the cell for a variety of operating and geometrical conditions. This is an abstract of a paper presented at the 2007 AIChE Annual Meeting (Salt Lake City, UT 11/4-9/2007).