A reduced 1D dynamic model of a planar direct internal reforming SOFC (DIR-SOFC) is presented in this paper for system research by introducing two simplifications. The two simplification strategies employed are called Integration and Average, respectively. The present model is evaluated with a detailed 1D SOFC model, which does not introduce the two simplifications, and a lumped parameter (i.e., OD) SOFC model. Results show that under the operating conditions investigated the accuracy of the reduced model is not significantly compromised by the two simplifications in prediction of the outlet gas flow rates and molar fractions, the outlet temperatures, and the cell voltage, while its computational time is significantly decreased by them. Moreover, it is quite simple in form. Therefore, the reduced SOFC model is attractive for system research. Compared with the lumped model, the reduced SOFC model is an improvement with regard to accuracy because it takes into account the spatially distributed nature of SOFCs to a certain extent. The discretized node number for solving the reduced model can be taken as an adjustable parameter in modeling, and is determined according to specific modeling requirements. (C) 2008 Elsevier B.V. All rights reserved.