Hydrogen Electrolyzer & Fuel Cell Manufacturing worked example

Hydrogen Purge Loss with hydrogen purge flow rate of 13 Nm³ / hr: a worked example

What does the result look like when hydrogen purge flow rate reaches 13 Nm³ / hr? The full calculation is worked below with real intermediate numbers. Use it when a test engineer or operations manager wants to know how much hydrogen is being burned through purges and inerting cycles, and whether a recirculation loop or shorter purge recipe is worth the engineering work.

The inputs for this scenario

  • Hydrogen purge flow rate: 13 Nm³ / hr (raised for this scenario; the documented default is 5)
  • Total hydrogen purge runtime per stack: 1.5 hr (unchanged)
  • Delivered hydrogen cost: 7.5 $ / Nm³ (unchanged)

Working through the calculation

  • Applying the documented formula (Hydrogen purge consumption per stack = purge flow rate × total purge runtime) to the inputs above produces each figure below.
  • At this operating point the engine returns 146 $ for hydrogen purge cost per stack, the number this scenario is built around.
  • At this operating point the engine returns 19.5 units for hydrogen purge consumption per stack.
  • At this operating point the engine returns 1.5 hr for total hydrogen purge runtime.
  • At this operating point the engine returns 7.5 $ / unit for delivered hydrogen cost.

How this compares with the baseline

  • Against the tool's baseline example, where hydrogen purge flow rate sits at 5 Nm³ / hr and the headline result is 56.25 $, this scenario comes in 160% above the baseline at 146 $.
  • A figure at this level is achievable when hydrogen purge flow rate is genuinely sustained, not just peaked for a shift. It assumes a constant purge flow over the runtime, so a recipe with ramps or intermittent purges needs an effective average flow rate rather than a peak value.

Results at a glance

  • Hydrogen purge cost per stack: 146 $ (headline result)
  • Hydrogen purge consumption per stack: 19.5 units
  • Total hydrogen purge runtime: 1.5 hr
  • Delivered hydrogen cost: 7.5 $ / unit

Run it with your numbers

  • Every input above is editable in the live Hydrogen Purge Loss calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.