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Fuel Cell Output Calculator

Work out fuel cell output instantly with clear inputs, formula shown and shareable results.

About Fuel Cell Output Calculator

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.

Formulas

Fuel cell output

Electrical (kW) = hydrogen (kg/h) x 33.33 x electrical efficiency

Voltage efficiency

Voltage efficiency = cell voltage / 1.23 V

Worked example

With the default values below, Fuel Cell Output Calculator returns Electrical Output of 91.658. Change any input above and every figure here is recalculated in your browser.

Inputs used

Hydrogen Consumptionminimum 0 kg/hour
5 kg/hour
Electrical Efficiencyaccepts 1–90 %
55 %
Heat Recovery Efficiencyaccepts 0–60 %
30 %
Cell Voltageaccepts 0.01–1.23 V
0.7 V

Results

Electrical Output
91.658
Recoverable Heat
49.995
Total Energy Utilisation
85.00%
Voltage Efficiency
56.91%

Step by step

  1. 1Values used
  2. 2Fuel cell output
  3. 3Voltage efficiency
  4. 4Electrical Output= 91.658
  5. 5Recoverable Heat= 49.995
  6. 6Total Energy Utilisation= 85.00
  7. 7Voltage Efficiency= 56.91

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is cell voltage below 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.

Does fuel cell efficiency fall at part load?

No, it improves — unlike an engine. Fuel cells are most efficient at low current density, which suits load-following applications.

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