A fuel cell system includes a fuel cell and a fuel infeed device. The fuel cell has first and second electrodes (cathode and anode). A layer with catalytic activity permeable to protons is between the electrodes. A fuel supply device provides a fuel, and a reactant supply device provides a reactant that reacts with protons from the fuel to produce current. The fuel and reactant supply devices are located directly on the face of an electrode. The fuel infeed device is connected to the fuel supply device for feeding in the fuel, the fuel supply device being one of the electrodes. The fuel supply device also stores the fuel. Besides supplying an electrical circuit with the fuel cell system as a micro energy supply device, the fuel cell system as a fuel infeed device also has an integrated electrolysis unit for regenerating the fuel supply.