In this work the identifiability and estimability of a 17-state nonlinear solid oxide fuel cell model are studied. A model is identifiable if the value of each model parameter can be uniquely determined under ideal conditions. A model is estimable if each parameter can be determined from a specific experimental design or data set. The identifiability of the fuel cell model was tested by partitioning the main model into four submodels whose identifiability could be verified. The estimability of the model was studied using sensitivity analysis. The model of interest was found to be identifiable in all parameters. The estimability of parameters was tested by varying the external load as a step and also as a square pulse. The charge transfer capacitance was found to be inestimable from a step change in the external load for a specific cut-off value, whereas all five parameters are estimable from a square pulse design of the external load input This study forms a basis for experimental studies. (C) 2008 Elsevier Ltd. All rights reserved.