Managing Generator Outages in the CAISO

Tracking and monitoring outages is a key function of managing generation assets in the California ISO (CAISO) market. CAISO Business Process Manuals and Operating Procedures detail the specific processes and procedures for coordinating generation outages. 

CAISO-generator-outages.jpgIf you are a Participating Generator within the CAISO footprint, your outage management procedures must be NERC and CAISO compliant, which means your company must follow a comprehensive set of operating procedures governing generator outage management.

Reporting outages to CAISO and other ISO and RTO’s requires complete and accurate outage planning and outage scheduling.  Click here to view CAISO’s Business Practice Manual for Outage Management.  CAISO’s BPM covers the business processes used by the ISO to coordinate the scheduling of generation and transmission outages and describes the roles and responsibilities of the ISO, its Transmission Owners, Transmission Operators and Scheduling Coordinators.

Versify is an Outage Management software vendor providing Generation and Transmission Outage Management System’s to help automate and improve outage planning, schedule and submission to CAISO.  Versify’s OMS is integrated with CAISO’s outage management system to submit and synchronize outages between systems.  

Overview of CAISO Generation Outages

Below are the CAISO’s data requirements for submitting outages.  Versify’s Outage Management System provides a single solution for managing outages in the CAISO region, including other ISO/RTOs such as MISO, PJM, ERCOT, SPP, NYISO and NEISO. 


Minimum Data Requirements for an Outage Request:

  • Resource information
  • Outage start date and time
  • Outage end date and time
  • Discovery date and time
  • Emergency return time
  • Nature of work (NoW)
  • Short description of outage

The NoW will determine what additional information is required for a valid request.

CAISO Outage Nature of Work:  The CAISO specifies over 20 NoW attributes that must be indicated with each outage request.  NoW attributes include: plant maintenance, ambient derates, fuel limitations, testing and communication issues that represent the cause of the outage or derate. 

Outage/Derate Types:  Outages may be planned well in advance or forced outages may be used for emergency maintenance. CAISO requires that each Participating Generator designate a single point of contact for managing outages and communicating with CAISO. Outage requests should be submitted via the CAISO OMS application.

Outages are assigned as either Forced or Planned based on the time the request is made relative to the outage start time.  Currently Planned outages must be submitted at least seven calendar days prior to the outage start time.  Outages submitted less than seven calendar days in advance will be considered Forced.  Requests for changes to approved Planned outages will not result in in a change to the outage type.

FAR vs. FAN:  All outages submitted to the CAISO are automatically classified as Final Approval Required (FAR) for Final Approval Not Required (FAN).  Classification or FAR or FAN is determined by the NoW included in the outage request or the type of resource.  For example, requests from Black Start resources are always classified as FAR.   

Resource Types and Classifications:  CAISO OMS resource types (Generator, Tie Generator, etc.) and resource classifications (Multi-stage Generator, Aggregate, etc.) also dictate what values are allowed for submission to the OMS.  For example, availability must be reported at the configuration level for multi-stage generators but A/S availability is reported at the generator level.

Outages and Resource Adequacy: For generators that are identified as Resource Adequacy (RA) resources, special rules apply on the timing that outages must be submitted, whether the outages require replacements or substitutions and what impact, if any, the outage will have on the RAIMM.

There are several unique aspects of managing Generation Outages in CAISO including:

  • Hourly Availability Profiles: allows Available MW changes over time within a single ticket
  • Treatment of overlapping derates: if overlapping derates exist generators are required to submit the minimum available MWs for the overlapping period
  • Vacated Periods: when the time of an outage is moved, generators must also submit a revised availability for the original timeframe
  • Change Requests: generators may withdraw a change request before it is accepted by CAISO
  • Treatment of Multi Stage Generators: availability for all configurations within a MSG must be submitted in a single ticket
  • Aggregates: CAISO accepts outage tickets for the rollup of smaller generators as aggregates
  • Ability to submit adjustments to ramp rates/PMIN/AGC MIN/Max within a single ticket

Versify Solutions, Inc. ( is an authority and leading provider of advanced enterprise situational awareness solutions for the electric power industry.  Versify’s application suite is a first-to-market software-as-a-service (“SaaS”) platform that uniquely addresses major challenges faced by companies involved in the generation, transmission, and sale of electric power.  Renewable energy operators, utilities and merchant power producers alike leverage the Company’s solutions to enable key digital transformation initiatives aimed at increasing revenue, reducing costs, mitigating compliance risks, and operating critical infrastructure assets more efficiently.  Versify’s OMS™ Outage Management System provides Generation Outage Management software, Transmission Outage Management software, NERC GADS/TADS reporting and is workflow enabled.  Versify’s PORTAL™ provides Power Generation Asset Management software, Operator Logs, NERC Compliance software and is also workflow enabled.  For more information, please visit