Patent ID: 6969561

Claim:
A power generation system comprising: a fuel cell stack comprising at least one fuel cell, an oxidant inlet, an oxidant outlet, a fuel inlet and a fuel outlet; a fuel delivery system for delivering fuel to the fuel inlet of the fuel cell stack; an oxidant delivery system for delivering oxidant to the oxidant inlet of the fuel cell stack; an oxygen sensor for measuring an oxygen concentration of ambient air in a vicinity of the power generation system; a hydrogen concentration sensor for measuring a hydrogen concentration in the ambient air in the vicinity of the power generation system; and a controller communicatingly coupled to receive signals from the oxygen sensor and from the hydrogen concentration sensor, the controller configured to cease delivery of fuel to the fuel cell stack by the fuel delivery system in response to the earlier of either the hydrogen concentration measured by the hydrogen concentration sensor exceeding a hydrogen concentration threshold or the oxygen concentration measured by the oxygen sensor falling below an oxygen concentration threshold.