SOFC is a fuel flexible technology suitable for producing clean energy. Understanding of the multi-reaction mechanism that a complex H-2-CO fuel presents to the electrochemical kinetics is numerically approached in this work. By using existing fundamental reaction mechanisms and kinetic parameters, elementary reactions involved in an SOFC anode have been assembled, modeled and analyzed. This involves both homogeneous and heterogeneous chemistry, electrochemistry and surface diffusion. The use of the patterned anode approach removes the mass transport complications and allows comparison with pre-existing experimental data. The model provides both polarization curves and surface coverage distribution, among other results, providing a high level of detail and understanding of the physical phenomena involved. In particular, analysis is focused upon understanding how the competitive H-2 and CO reactions behave. The presence of CO was found to stabilize OCV response to temperature and while it occupied most of the active sites it did not penalize overall performance except when significant product species were present. (C) 2016 The Electrochemical Society. All rights reserved.