out_epacems__yearly_operational_characteristics
Return to SearchAnnual time series of estimated operational characteristics for EPA CEMS emissions units.
- Most-recent data:
2025
- Processing:
Data has been expanded into a wide/denormalized format, with IDs and codes accompanied by human-readable names and descriptions.
- Source:
EPA Hourly Continuous Emission Monitoring System (CEMS)
- Primary key:
plant_id_epa, emissions_unit_id_epa
Usage Warnings
Contains estimated values.
This table is experimental and/or a work in progress and may change in the future.
This table estimates values from a configurable trailing window of EPA CEMS quarters ending at the most recent complete year (12 quarters, i.e. the most recent three full years, in production). Builds that only have a limited number of EPA CEMS quarters available, such as the fast ETL and CI, will produce estimates from a shorter, less accurate window.
Additional Details
This table summarizes several inferred operational characteristics for each EPA CEMS emissions unit using hourly CEMS gross load and fuel heat content over a trailing window of EPA CEMS quarters. In production this window is the most recent three full years (12 quarters) of data, ending at the most recent complete calendar year.
The values are not directly reported to source agencies. They are derived from observed hourly operations. These variables should be treated as an analytical estimate rather than as reported plant characteristics.
For methodological details, see /methodology/operational_characteristics.
Columns
The ORISPL ID used by EPA to refer to the plant. Usually but not always the same as plant_id_eia.
Emissions (smokestack) unit monitored by EPA CEMS.
The unique six-digit facility identification number, also called an ORISPL, assigned by the Energy Information Administration.
Four-digit year in which the data was reported.
Two letter US state abbreviation.
Maximum observed gross load for an EPA CEMS emissions unit.
Estimated minimum stable operating level as a fraction of maximum gross load.
Minimum observed duration of a consecutive run at or above the minimum stable level.
Minimum observed duration of a consecutive non-operating run.
Estimated heat rate at the highest observed load-factor bin for an EPA CEMS emissions unit.
Estimated heat rate at the minimum stable operating level for an EPA CEMS emissions unit.
Median ramp rate among the steepest 5% of observed upward ramps expressed as a fraction of maximum gross load per minute.
Median ramp rate among the steepest 5% of observed downward ramps expressed as a fraction of maximum gross load per minute.