A method for controlling a fuel cell during operation of the fuel cell by determining a power requirement of a load electrically connected with the fuel cell, sensing an electromotive force of the fuel cell, determining an available electrical power from the fuel cell based on the sensed electromotive force of the fuel cell, calculating a deviation between the determined power requirement of the load and the available electrical power from the fuel cell, and controlling thermal operating parameters of the fuel cell to compensate for the calculated deviation. Also, a fuel cell system configured to perform such a method.