Generation Capacity Factor Calculator

How the generation capacity factor calculator works

Continuous reference output = entered capacity in MW × period hours. Capacity factor against that reference = actual generation in MWh ÷ continuous reference MWh × 100. Average output = generation ÷ period hours. Capacity is treated as constant throughout the period.

A zero reference capacity or zero duration is valid only with zero generation; the corresponding capacity factor is undefined. Average output is undefined for zero hours. Positive generation with zero capacity or duration is rejected because its denominator cannot describe the same generating period.

Ratios above 100% remain visible with a prompt to check reference capacity and data boundaries. They are not clamped. Use consistent AC/DC, net/gross, seasonal and time bases; a changing reference capacity needs a time-weighted model that this tool does not perform.

The signed difference between continuous reference output and actual generation is a mathematical comparison, not avoidable lost production or an energy forecast. EIA explains actual-versus-reference output and notes the time-adjusted capacity basis of its published statistics. This simple entered-reference model does not reproduce every EIA reporting adjustment.

Worked example

A constant 5 MW reference over 8,760 hours corresponds to 43,800 MWh. Actual generation of 10,000 MWh gives about 22.831% capacity factor and 1.142 MW average output. The mathematical reference-output difference is 33,800 MWh. Entering 21,900 MWh gives exactly 50%.

Sources and assumptions

The source material explains the underlying calculation or pricing structure. Entered prices, costs, schedules and scenario choices are your assumptions; this tool does not obtain supplier quotes or predict actual results.

• EIA: generation capacity, generation and capacity factor