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Market Notice
May 10, 2019


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Legal and Regulatory

Market Operations
Section 43A.6.3 Report of Non-RA Capacity for April 2019


The California ISO has published its monthly report of market and non-market commitment of non‑resource adequacy (RA) capacity for the month of April 2019.


ISO Tariff section 43A.6.3 requires the ISO to publish a monthly report of market and non-market commitment of non-RA capacity. The April 2019 report is available at


Starting with the October 2018 report, the ISO has enhanced the methodology used to identify the non-RA capacity. Previously the capacity was estimated on instances where resources were only committed. The enhanced report will more granularly report the non-RA capacity based on resource dispatches. With a larger set of records to include, the monthly non-RA capacity report now includes a spreadsheet listing all the instances for the month. This spreadsheet is available at


The report includes the following:

  • name of the resource;
  • utility service area and local capacity area (if applicable);
  • maximum non‑RA capacity dispatched in response to the event (MW);
  • how capacity was procured (for example, by residual unit commitment or exceptional dispatch); and
  • reason the non‑RA capacity was dispatched (either through market optimization or exceptional dispatch).

The "maximum" non-RA capacity includes non-RA capacity, which includes capacity payment mechanism capacity, committed as a result of physically binding start-up instructions and incremental energy dispatches.  Exceptionally dispatched non-RA capacity will be reported separately from in-market non‑RA capacity for each trading day. Exceptional dispatches for the purposes of testing will not be included.  Maximum non-RA capacity will not include any non‑RA capacity below the resource’s minimum operating level if the resource has sold any capacity below that level as RA capacity. When this occurs, the RA must offer obligation applies to the minimum operating level (PMin) available.


Market commitments and dispatches result from a security constrained optimization based on bids and self-schedules from all capacity (RA and non RA) that has submitted bids. The ISO may also issue exceptional dispatches to commit and dispatch resources, for which the ISO uses available information to select the most economic resources for exceptional dispatch that can meet the reliability need.  This generally results in exceptional dispatches only of RA capacity. The ISO had 4 exceptional dispatches of non-RA in the month of April 2019.


Phillip Booker at

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California Independent System Operator | P.O. Box 639014 | Folsom, CA 95630 | United States