A fuel processor (10) comprises a supply of natural gas (12) and a compressor (14), which compresses the natural gas and supplies the natural gas to a partial oxidation reactor (16). A supply of oxygen (20) supplies the oxygen to the partial oxidation reactor (16). The partial oxidation reactor (16) partially reacts the natural gas and the oxygen to form a mixture comprising hydrogen and carbon dioxide. The partial oxidation reactor (16) supplies the mixture of hydrogen and carbon dioxide to a turbine (20). The turbine (20) is arranged to drive the compressor (14). The turbine (20) expands and cools the mixture of hydrogen and carbon dioxide and supplies the mixture of hydrogen and carbon dioxide to a fuel cell stack (22) requiring hydrogen and/or carbon dioxide.