A novel stochastic structure model has been developed for the purpose of investigating the dynamic molten carbonate fuel cell (MCFC) performance, in particular, the effect of constant change of electrolyte distribution with time. As a preliminary application and verification of this model, the steady-state relationship between electrolyte distribution and cell performance has been investigated using the agglomerate model of porous electrode performance based on the stochastic structure. To investigate the optimization of electrode structure for maximum performance, the effect of microstructure and physical properties on electrode performance is analyzed taking into account total polarization (cell voltage loss), using the dimensionless-number (K) approach. This makes it possible to explore the effect of electrode microstructure on fuel cell performance, and power density in particular. (C) 2004 The Electrochemical Society.