Performance analysis of the solid oxide fuel cell - micro gas turbine (SOFC-MGT) hybrid system has been made assuming the fuel to be methane-based artificial ones including H2, CO, CO2, H2O or N2 of different concentration in preparation for the study of biomass fuelled SOFC-MGT hybrid system. This is based on the fact that the chemical composition of biomass fuel produced from different fuel production processes is diversified, i.e. in one case one chemical species rich in concentration and in another case another chemical species rich. In the analysis is used the multi-stage model for internal reforming SOFC module developed previously with some modification. With this model, studies cover not only the performance of the hybrid system but also the spatial distributions of temperature and concentration of some chemical species inside the module, namely in the cell stack and in the internal reformer.