Glossary
capacity factor
The capacity factor is the ratio of actual generation to maximum possible generation over a period - generation divided by installed capacity, expressing how intensively an asset runs. EIA publishes dedicated capacity-factor tables in its Electric Power Monthly, OPSD ships capacity-normalized wind and solar profiles, and Renewables.ninja offers simulated country-aggregated datasets under commercial delivery terms-NC.
What is a capacity factor?
A plant running flat-out all year scores 1.0; real fleets score lower because of maintenance, fuel limits and - for renewables - weather. EIA's Electric Power Monthly carries 'capacity factors' among its tags, with a short_description covering 'retail sales/revenue/prices, capacity factors, additions/retirements'.
Renewables get dedicated treatment: OPSD's Time Series Package includes 'installed capacity and capacity-normalized profiles' tagged capacity factors, letting analysts separate weather effects from fleet growth. Renewables.ninja publishes 'downloadable country-aggregated capacity factor datasets under commercial delivery terms-NC' from simulation rather than metering.
Why does the capacity factor matter when choosing a dataset?
Asset economics hinge on it. Revenue scales with actual output while capital cost scales with installed capacity, so the ratio decides project viability - and comparing technologies without it misleads badly.
Source provenance changes interpretation though: measured factors (EIA tables) describe what happened; simulated ones (Renewables.ninja, under commercial delivery terms-NC licence) estimate what could happen at candidate sites. Capacity-normalized OPSD profiles serve a third purpose - isolating resource quality from fleet expansion. Mixing the three without labels produces forecasts no one can audit.
How do you evaluate capacity factor data in a source?
- “Identify measured versus simulated.” EIA Electric Power Monthly reports observed fleet factors; Renewables.ninja simulates them - label which you hold.
- “Check normalisation options. ”OPSD provides capacity-normalized profiles alongside installed capacity, enabling weather-only comparisons.
- “Watch denominators. ”Factors computed against nameplate versus net capacity differ; confirm the basis.
- “Respect licence terms. ”Country datasets under commercial delivery terms-NC restrict commercial redistribution.
- “Pair with additions and retirements. ”Fleet change explains factor drift as much as weather.
Related terms
- hourly-time-series-grid - the structure underlying normalized profiles.
- load-factor - the demand-side cousin of the metric.
- nameplate-capacity - the denominator's anchor.
- net-generation - the numerator's source.
Sector hubs: electric-utilities data, independent-power-producers-energy-traders data.
Frequently asked questions
How is capacity factor calculated?
Actual generation divided by maximum possible generation over the period - equivalently output as a share of installed capacity.
Where can I find country-level renewable capacity factors?
Renewables.ninja publishes downloadable country-aggregated capacity factor datasets under commercial delivery terms-NC, and OPSD offers capacity-normalized hourly wind and solar profiles.
Datasets containing this field
Datasets containing capacity factor
6 datasets carry capacity factor in the catalog. Open one, count the fields, judge for yourself.
EIA Consumption & Efficiency - Electricity Surveys (RECS/CBECS/MECS)
CAISO OASIS — Open Access Same-time Information System
EIA API Technical Documentation (v2 Routes & Facets)
EIA Electric Power Annual
EIA Electric Power Monthly
EIA Form EIA-860 — Annual Electric Generator Inventory
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