Fuel cells (FCs) are promising for future energy systems, since they are energy efficient and fuel can be produced locally. When hydrogen is used as fuel, there are no emissions of greenhouse gases. In this study a two dimensional CFD (COMSOL Multiphysics) is employed to study the effect from porous material surface area ratio on reforming reaction rates and gas species distributions for an anode-supported solid oxide fuel cell (SOFC). FCs can be considered as multifunctional energy devises, combining (electro-) chemical reactions, heat exchange, gas- and ionic transport. All these functions are strongly integrated, making modeling an important tool to understand the couplings between mass-, heat-, momentum transport and chemical reactions. Steam reforming takes place at the nickel material surfaces in the anode and water-gas shift reaction occurs where fuel gas is present. Benefit from the internal reforming is that the energy conversion efficiency will be higher, compared to the case of pure hydrogen as fuel.