District Energy & Thermal Network Equipment worked example

Boiler Capacity at 65% expected boiler availability: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop expected boiler availability to 65%, then walk the calculation through step by step. Estimate dependable boiler plant capacity for a district heating, campus hot-water, or steam network after unit availability and capacity credit are applied.

The inputs for this scenario

  • Rated boiler thermal capacity: 4 MW or MMBtu/hr per boiler (held at the documented default)
  • Boilers available for dispatch: 480 boilers (held at the documented default)
  • Expected boiler availability: 65 % (the input this scenario stresses; the baseline uses 90)
  • Usable capacity credit: 97 % (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Installed boiler capacity = rated boiler thermal capacity × boilers available for dispatch.
  • Dependable boiler capacity works out to 1,211 MW or MMBtu/hr at these inputs, and this is the headline figure for the scenario.
  • Installed boiler capacity works out to 1,920 MW or MMBtu/hr at these inputs.
  • Boiler availability capacity loss works out to 672 MW or MMBtu/hr at these inputs.
  • Boiler derating or reserve loss works out to 37.44 MW or MMBtu/hr at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where expected boiler availability sits at 90% and the headline result is 1,676 MW or MMBtu/hr, this scenario comes in 27.78% below the baseline at 1,211 MW or MMBtu/hr.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to expected boiler availability, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. Simple multiplicative derating treats availability and capacity credit as steady factors; it does not model correlated outages, fuel curtailment, or simultaneous peak coincidence across connected buildings.

Results at a glance

  • Dependable boiler capacity: 1,211 MW or MMBtu/hr (headline result)
  • Installed boiler capacity: 1,920 MW or MMBtu/hr
  • Boiler availability capacity loss: 672 MW or MMBtu/hr
  • Boiler derating or reserve loss: 37.44 MW or MMBtu/hr

Run it with your numbers

  • To rerun this with your own numbers, open the live Boiler Capacity calculator, set expected boiler availability to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.