Work out fuel cell output instantly with clear inputs, formula shown and shareable results.
Fuel cell electrical output is hydrogen mass flow times lower heating value times electrical efficiency. Because a fuel cell is not a heat engine, it is not bound by the Carnot limit, and 50-60% electrical efficiency is achievable. Cell voltage against the thermodynamic 1.23 volts gives voltage efficiency, the fundamental measure of polarisation loss.
Fuel cell output
Electrical (kW) = hydrogen (kg/h) x 33.33 x electrical efficiency
Voltage efficiency
Voltage efficiency = cell voltage / 1.23 V
Activation, ohmic and mass transport losses. Operating at 0.6-0.7 V per cell trades efficiency for power density; running at higher voltage is more efficient but needs a larger, costlier stack.
No, it improves — unlike an engine. Fuel cells are most efficient at low current density, which suits load-following applications.