Accurate and complete outage scheduling is vital to reliable operation of the transmission system.

Managing outages helps ensure system reliability

The ISO coordinates outage schedules for maintenance, repair and construction within the ISO grid to maintain system reliability, maximize schedule feasibility and ensure effective planning for resource use.

Transmission outage reports

All transmission outages must be reported to the ISO with a description of the cause and all remedial actions taken. Information is confidential. The ISO processes, coordinates, and approves transmission outages to ensure system reliability in its controlled grid area.

Available reports

• Short-term transmission outage report published hourly - all transmission outages up to the next seven days.
• Long-term transmission outage report published daily - all transmission outages up to the next 1000 days.

View transmission outage reports*

*Requires a valid user certificate

The daily long-term transmission outage report will not be generated during certain monthly congestion revenue rights (CRR) periods as noted below:

2024 Monthly PeriodStop Date/TimeStart Date/Time
January01/03/2024 5:00 p.m.01/23/2024 5:00 p.m.
February02/02/2024 5:00 p.m.02/22/2024 5:00 p.m.
March03/04/2024 5:00 p.m.03/22/2024 5:00 p.m.
April04/03/2024 5:00 p.m.04/23/2024 5:00 p.m.
May05/02/2024 5:00 p.m.05/23/2024 5:00 p.m.
June06/03/2024 5:00 p.m.06/21/2024 5:00 p.m.
July07/02/2024 5:00 p.m.07/22/2024 5:00 p.m.
August08/02/2024 5:00 p.m.08/21/2024 5:00 p.m.
September09/04/2024 5:00 p.m09/23/2024 5:00 p.m.
October10/02/2024 5:00 p.m.10/23/2024 5:00 p.m.
November11/04/2024 5:00 p.m.11/20/2024 5:00 p.m.
December12/06/2024 5:00 p.m.12/24/2024 5:00 p.m.

Stop Date/Time: Date and time when daily long-term outage report will stop being posted
Start Date/Time: Date and time when daily long-term outage report will start being posted

Curtailed and non-operational generator reports

A daily report of California power plants that are not operational due to planned or unplanned outages.

Please be advised that system conditions are dynamic, and this information is subject to change without further notice. Decisions based on information contained in the reports are the sole responsibility of the user.

Glossary for curtailed/non-operational generator reports

This list is posted in accordance with California Public Utilities Code Section 352.5. Section 352.5 requires the ISO to make publicly available a daily list of all power plants located in the state that are not operational due to a planned or unplanned outage. At this time the ISO does not have information regarding the operational status of all plants located in the state. Accordingly, the non-operational generator report includes only the units for which the ISO has information.

This report includes all outages/curtailments that may be effective for the indicated dates. Because outages may overlap or may not all be simultaneously in effect, this report may indicate a different total outage/curtailment than a real-time report using only data from curtailments/outages in effect at that time.

Starting July 10, 2001, the ISO publishes a report of unit availability. This reflects the status of units at that time only. The approximate publishing time for these reports is 15:15 Pacific Time.

Outage MRID
The ID uniquely identifying the outage.

Resource ID
The ISO resource ID for this unit.

Resource Name
The Name of the generator unit which is being reported upon. Individual outages for each unit covering the reporting period are summarized under a single record.

Outage Type
Outage type is either Planned or Forced. If multiple outages exist for a resource, these outages are stacked by resource ID. 

Nature of Work (NOW)
This is nature of work associated with the outage. Please refer to the Outage Management BPM for details regarding the various NOW and their usage.

Curtailment Start and End Date Time
This is the period during which there is a curtailment reported on the unit. This may span a portion of the day or could be longer. For outages that span beyond the trade date, the end date will be blank. If the curtailed MW differ within the outage for that trade date, then this is captured by multiple break-points in the outage card. In this case, the report will display all the break-points i.e. the curtailment start and end date time, with the varying curtailed MW. 

Curtailment MW or Curtailed 
This figure represents the total megawatts for all outages active any time during the day being reported on up to the total Unit Maximum for the unit. For units reporting multiple outages during the 24 hour period of the report, this number will probably reflect a higher curtailment than is actually in effect at any given time. Indicated as "Curtailed" on the Curtailed and Non-Operational Generation snapshot.

Resource PMax MW (Capacity)
The unit maximum rating in megawatts. Indicated as "Capacity" on the Curtailed and Non-Operational Generation snapshot.

Net Qualifying Capacity (NQC)
ISO publishes the NQC for the resources in the CAISO BA on the caiso.com website. The numbers on this report refer to the same data.

The ISO documents the location for each unit and this information is locally maintained in webOMS. If a unit's zone is not captured, the field will display a blank value.

Balancing Area (BA)
The Balancing Area consuming the resource. 

Information for other control areas
The ISO depends upon the other control areas for outage information for units in their control area. The information presented in the prior trade date report, covers the outages in the CAISO BA. The current trade date projected report contains outages in the following BAs: CAISO, BANC, TIDC, LADWP and IID.

NOTE: The ISO does not generally receive specific enough information from other control areas to indicate whether a unit is unavailable at the time of the report. Generally, the ISO receives only a set of dates when the units are/will be unavailable.

Related application(s) and access

Report and manage generation and transmission outages through this web-based system. The webOMS technical specification documents are available at https://developer.caiso.com (developer account required).

Related ISO Tariff and Business Practice Manuals

All forced outages must be reported to the California ISO with a description of the cause and all remedial actions taken.

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