Chemical looping combustion (CLC) is a combustion process in which the different fuels can be burnt with inherent separation of CO,. A CLC system has two interconnected reactors named as fuel and air reactor. In the fuel reactor) metal oxides supply oxygen for the combustion of the gaseous fuel, and the metal oxides are regenerated (oxidized) with air in the air reactor. The feasibility of a CLC system greatly depends oil the selection of appropriate metal oxides as oxygen carriers. In the present study, NiO/NiAl2O4 and Cu0.95Fe1.05AlO4 were tested experimentally in a fluidized-bed reactor as a function of number of oxidation-reduction cycles, temperature and effect of steam mixed with methane as a fuel. A 30-MWfuel CLC system was simulated for the combustion of biogas, syngas and methane oil the basis of the experimental results.