High efficiency fuel cell

Fuel cell arrangement having an improved efficiency. The arrangement comprises one or more fuel cell sections 110 and a catalyst section 200 and a control unit 300. The fuel cell section comprises a water inlet 111, a hydrogen outlet 112 and an oxygen outlet 113. The catalyst section comprises a hydrogen inlet 21), a carbon oxide inlet 214 having a first controllable valve 215 and a methane outlet 216, wherein the hydrogen outlet of the first fuel cell section is coupled to the hydrogen inlet of the catalyst section, and the catalyst section is adapted to convert hydrogen and carbon oxide into methane, wherein the control unit is adapted to control the first controllable valve so as to obtain an optimum converting process to convert hydrogen and carbon oxide into methane.