TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred System: In the aircraft fuel cell system, the fuel was produced by a biomass-to-liquid method comprising: (a) pyrolysis of the biomass in order to obtain a carbon monoxide/hydrogen mixture (synthesis gas); (b) conversion of the synthesis gas to a mixture of liquid hydrocarbons; and (c) processing of the mixture in order to obtain the fuel. The fuel was produced from bio oils comprising the method steps of: (a) extraction of oil from a biomass containing oil; (b) processing of the oil by catalytic hydrocracking, hydration or transesterification in order to obtain a mixture of hydrocarbons; and (c) processing of the mixture in order to obtain the fuel. The aircraft fuel cell system comprises a cleaning unit arranged between the reactor and the fuel cell to separate impurities contained in the generated gas that contains hydrogen. Heating apparatus comprises a burner that is supplied with the synthetic fuel and/or with impurities which were separated, by the cleaning unit, from the generated gas that contains hydrogen. The reactor is designed to carry out steam reforming, autothermal steam reforming or catalytic partial oxidation. Reforming is to be carried out at a reaction temperature ranging from 500 degrees C to 1000 degrees C, preferably from 600 degrees C to 700 degrees C, and at a reaction pressure ranging from 10 bars to 25 bars. The reactor is designed to carry out partial dehydration. Reforming is to be carried out at a reaction temperature ranging from 300 degrees C to 500 degrees C, preferably from 400 degrees C to 450 degrees C, and at a reaction pressure ranging from 10 bars to 25 bars. The aircraft fuel cell system further comprises a condensation device that is arranged between the reactor and the cleaning unit in order to separate the dehydrated residual fuel from the generated gas that contains hydrogen. The burner is supplied with the dehydrated residual fuel. The cleaning unit and/or the condensation device are/is connected to the engine in order to feed to the engine the impurities separated in the cleaning unit, and/or the dehydrated residual fuel. The fuel cell is thermally coupled to the heating apparatus in order to utilize the heat generated during operation of the fuel cell for the purpose of heating the fuel supplied to the reactor.