Capacity Factor Calculator Formula

Understand the math behind the capacity factor calculator. Each variable explained with a worked example.

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Formulas Used

Capacity Factor

capacity_factor_pct = actual_output_mwh / max_output * 100

Maximum Possible Output

max_possible_mwh = max_output

Unused Capacity

unused_capacity_mwh = max_output - actual_output_mwh

Variables

VariableDescriptionDefault
actual_output_mwhActual Energy Output(MWh)2500
rated_capacity_mwRated (Nameplate) Capacity(MW)2
period_hoursTime Period(hours)8760
max_outputDerived value= rated_capacity_mw * period_hourscalculated

How It Works

Power Plant Capacity Factor

The capacity factor measures how much energy a plant actually produces compared to its theoretical maximum if it ran at full power continuously.

Formula

Capacity Factor = Actual Output / (Rated Capacity x Hours) x 100%

Typical capacity factors: Nuclear 90-93%, Natural gas 40-60%, Wind onshore 25-45%, Solar PV 15-30%. Higher factors mean better utilization of installed capacity.

Worked Example

A 2 MW wind turbine produces 2,500 MWh in one year (8,760 hours).

actual_output_mwh = 2500rated_capacity_mw = 2period_hours = 8760
  1. 01Maximum output = 2 MW x 8,760 hr = 17,520 MWh
  2. 02Capacity factor = 2,500 / 17,520 x 100 = 14.3%
  3. 03Unused capacity = 17,520 - 2,500 = 15,020 MWh

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