Work out power plant heat rate instantly with clear inputs, formula shown and shareable results.
Heat rate is fuel energy input per unit of electrical output, in kilojoules per kilowatt-hour. It is the reciprocal of efficiency: efficiency = 3600 / heat rate. Net heat rate uses output after station auxiliaries, which consume 5-8% of gross output in a coal plant and 2-3% in a gas turbine plant.
Heat rate
Heat rate (kJ/kWh) = fuel energy input / net electrical output
Efficiency
Efficiency % = 3600 x 100 / heat rate
About 9500-11,000 kJ/kWh for a subcritical coal unit (33-38%), 8000-8500 for supercritical, and 6000-6600 for a modern combined cycle gas plant (55-60%).
Only net output reaches the grid and earns revenue. A plant with efficient auxiliaries has a better net heat rate even at the same boiler and turbine performance.