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Proposed Revision Request Detail Help
PRR Life Cycle*****Stakeholder Meeting on Recommendation****
PRR Details
PRR #
1688
Title Formula details on fifteen-minute market ex-post capacity calculations
Date Submitted 7/15/2026 9:24 AM
PRR Category A
Priority Normal
Owner Martin, Michael (CAISO)
Status Stakeholder Meeting on Recommendation
Status End Date 9/16/2026 11:59 PM
Related BPM Market Operations
BPM Section Appendix P FMM Ex-Post Capacity Calculations (New)
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Existing Language

​See Attached

Proposed Language

​See Attached​

Reason For Revision

This in an informational BPM update that outlines the formulas used in the FMM Ex-Post Capacity Calculations as well as graphed examples.​

Click here to view the Recommendation Details for this PRR
BPM PRR Submitter

Martin, Michael (CAISO)
Modified BPM language proposed by the PBM Chnage Management Coordinator

​Approve the BPM PRR as submitted

Identification of the authorship of comments

Approve as sumitted
Action

Approve the BPM PRR as submitted

Note that details answers to the questions provided by PGE are in process. 
Statement of apparent requirements of the BPM PRR

Notified PGE that answers are forthcoming.
Priority and rank for any BPM PRR requiring a CAISO system change

NA
Proposed effective date(s) of the BPM PRR

Other recommended actions

Announcements
No Announcements has been posted for this PRR.
Impact Analysis
PRR 1688 Impact Analysis Form.doc    
Notes:
Initial Comments
PG&E offers the following comments:

1. What is driving this PRR?
• What problem is this PRR addressing?
• Why is this coming up now?

2. Is the calculation accurate?
2a. Calculation Questions:
• The note in section 1.1.3 states that “The time-block will be the entire month window for all resource types with the exception of interties, where the time-block can be any time frame window within the month.” Please explain how the FMM Ex Post Capacity Allocation is connected to this time-block.
• In section 1.1.3, the mathematical formulation for Resource Adequacy (RA) Capacity value FMM Ex Post Capacity Allocation is determined by the minimum between the shown RA (which is the maximum of available showing) and maximum of the daily RA. PG&E would like to understand CAISO’s rationale for structuring the formula in this manner.
• How is the RA Capacity variable connected to existing RA concepts (for example, Net Qualifying Capacity)? To better understand the RA Capacity variable’s representation, PG&E requests additional explanation regarding the derivation of Generic RA Capacity and Flex RA Capacity, the treatment of RA substitutions between RA showing and RA capacity, the rationale for using MAX(Generic RA Capacity, Flex RA Capacity), and the intended physical interpretation of RA Capacity when converting daily RA showings into FMM overlapping IR and RC capacity quantities. A detailed numerical example would go a long way towards this effort.
• In section 1.1.3, is the exclusion of Regulation Down (RD) from the IR & RC RA overlap FMM Ex Post Capacity Allocation because that calculation is only intended for upward overlap calculations? If so, why?

2b. Prioritization Questions:
• Please explain the rationale and tariff source for the priority of market awards used in the FMM Ex Post Capacity Allocation. This methodology seems to imply that incongruent awards may be awarded within an FMM period and must be accounted for.
• Is the exclusion of Regulation Down (RD) from the IR & RC RA overlap FMM Ex Post Capacity Allocation because that calculation is only intended for upward overlap calculations?

3. Please list all of the ways that Appendix P will impact CAISO processes.
• Settlements: PG&E requests CAISO explain all of the places that this calculation will impact settlements.
• Market Operations: Also, PG&E requests that the CAISO provide an updated redline version of the Market Operations BPM for stakeholders to better understand how the proposed Appendix P impacts the Market Operations BPM.
• Other: PG&E requests CAISO list any other ways that Appendix P will impact CAISO processes.
8/19/2026 9:13 AM
Logged By - alan.meck@pge.com (CAISO)
Recommendation Comments
Although the Six Cities did not submit Initial Comments on PRR 1688, PG&E submitted extensive comments on PRR 1688 requesting clarifications or explanations on a number of elements included in the PRR.  The CAISO has committed to respond in detail to PG&E’s comments, but the detailed response has not yet been posted.  The Six Cities would like to have the opportunity to review (and potentially follow up on) the CAISO’s responses to PG&E’s Initial Comments before the Recommendation Comment period for the PRR expires.  Accordingly, the Six Cities request that the CAISO extend the Recommendation Comment period for PRR 1688 for two weeks beyond the posting of its responses to the PG&E Initial Comments.
9/16/2026 2:43 PM
Logged By - bblair@thompsoncoburn.com (CAISO)
Attachments