A method and apparatus for providing a substantially constant output voltage from a fuel cell, notwithstanding output current variations, is disclosed. The voltage and secondarily the current of the cell is determined at least periodically. The pressure of the reactant gas in the fuel cell is then regulated so substantially the nominal voltage is maintained. The temperature in the fuel cell may also be regulated to maintain the nominal output voltage. Also, a method and apparatus for minimizing the parasitic power drain in a electric power generation system is disclosed. The fuel cell is fed with an reactant gas by a compressor driven by parasitic power drawn from the fuel cell. The method is carried out by determining that the output current of the fuel cell has changed, and changing one or more or the pressure, the mass flow rate and the reactant utilization ratio of the reactant in the fuel cell, thereby changing the amount of the parasitic power drawn from the electrical power output to drive the compressor.