California ISO - All comments

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES appreciates the productive discussion at the November 12 stakeholder meeting and recognizes the ISO's commitment to addressing critical operational challenges in storage. The meeting demonstrated that significant common ground exists among storage operators, ISO staff, and other stakeholders regarding the need for expedited market design improvements. AES particularly supports the working group's focus on three interconnected issues—nonlinearity representation, state-of-charge management, and default energy bid (DEB) modifications—which are inseparable in addressing the inadequacy of the current market design in capturing the operations of battery energy storage systems. The REV Renewables presentation effectively illustrated that practical, implementable solutions exist that can balance CPUC resource adequacy requirements with operational flexibility needs. AES endorses the principle that regulatory validation requirements should not unnecessarily constrain operational parameters in CAISO's real-time and day-ahead markets. We are encouraged by the technical depth of discussions regarding foldback constraints, SOC management, and uplift mechanisms.

However, AES is concerned that some proposed approaches may inadvertently restrict operational flexibility by excluding portions of a storage resource's physical capabilities from market participation. Storage resources must retain the ability to access their full operational range to effectively manage state-of-charge targets and respond to real-time grid conditions, as excluding the foldback region from dispatchable operations would create perverse outcomes in which available energy becomes inaccessible. AES strongly supports the REV proposal to integrate foldback parameters into the market model via Master File fields, preserving operational flexibility while accurately reflecting battery physics constraints. This separation of CPUC resource adequacy validation from operational market parameters represents sound policy direction. AES urges the ISO to prioritize engineering resources to develop detailed technical specifications for foldback parameter integration by the next stakeholder meeting. CAISO should implement a modeling solution in Fall 2026 release and consider this improvement essential for EDAM. The stakeholder process needs to discuss implementation details developed by CAISO.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

The California Community Choice Association (CalCCA) appreciates the opportunity to comment on the California Independent System Operator’s (CAISO) Storage Design and Modeling Working Group Meeting. In summary, the CAISO should:

Adopt CalCCA’s alternative resource adequacy (RA) accounting proposal for storage resources with foldback included in their PMax, if the CAISO puts forth a proposal in the California Public Utilities Commission’s (CPUC) RA proceeding;
Prioritize the development of a Master File parameter as a market-based solution to reflecting foldback in the market and ensuring known resource characteristics are modeled rather than reflected in a resource’s unforced capacity value;
Adopt the stakeholder-supported, principle-based approach in which negative revenues attributed to market algorithms or CAISO action may warrant uplift and negative revenues attributed to bidder behavior may not warrant uplift;
Require the submission of the day-ahead initial state-of-charge (SOC) parameter within a certain accuracy range to be eligible for bid cost recovery (BCR); and
Do not exempt storage resources from local Market Power Mitigation (MPM) and instead seek to enhance the tools and methodologies used to manage storage resources in the market and provide uplift payments when warranted.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

The California Energy Storage Alliance (CESA) appreciates the opportunity to comment on the November 12 hybrid meeting. CESA applauds the CAISO for holding a hybrid in-person meeting. While there was limited attendance by stakeholders, those that attended benefited from the interpersonal interactions with other concerned stakeholders and CAISO staff.

Although there were numerous interesting presentations at the meeting, in order for the discussions to meaningfully advance the Storage Design and Modeling initiative, CESA requests that CAISO clearly outline before the presentations are given how they are expected to address the core analytical questions and move stakeholders toward a decision point and an implementable market design solution.

In summary, CAISO should implement a nonlinearity modeling solution in Fall 2026 release and consider this improvement essential for EDAM. The stakeholder process needs to discuss implementation details developed by CAISO. Any RA capacity accreditation concerns should be clarified at the CPUC and not impact operations.

Lastly, CAISO should withdraw the BPM Proposed Revision Request (PRR) clarifying that distribution-level charging constraints fall under the ‘ambient due to fuel insufficiency’ nature of work. It was inappropriate for CAISO to move forward with a PRR given the limited discussion on the topic in the last working group.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Comments on Storage Design and Modeling

Working Group Presentation on November 12, 2025

Department of Market Monitoring

November 26, 2025

Summary

The Department of Market Monitoring (DMM) appreciates the opportunity to comment on the Storage Design and Modeling working group presentation held on November 12, 2025.[1]

DMM appreciates the ISO’s attention to storage bid cost recovery (BCR) issues. DMM continues to support eliminating day-ahead (DA) BCR for storage resources unless specific instances are identified where DA BCR is clearly appropriate to support efficient market outcomes for storage resources.[2] DMM continues to recommend a similar approach to establishing real-time (RT) BCR eligibility for storage resources, with a default of no BCR, and eligibility for RT BCR only established under specific situations when it is deemed appropriate. Specifically, DMM recommends the ISO eliminate RT BCR for storage resources buying back day-ahead schedules due to insufficient state-of-charge (SOC) by default, only allowing this source of RT BCR in specifically identified situations deemed appropriate.

If the ISO instead chooses to maintain default eligibility of batteries for RT BCR, and attempts to address each individual scenario that could lead to unwarranted RT BCR, DMM supports the proposal to reduce day-ahead buybacks due to insufficient SOC by better incentivizing accurate submissions of the DA initial state-of-charge (DA ISOC) parameter. Even if the DA ISOC is accurate, there is still a bidding incentive issue if storage resources receive BCR for day-ahead buybacks due to insufficient SOC. DMM supports the ISO requiring DA ISOC submission independent of the BCR issues. DMM recommends strengthening the tariff language to better define expected use of the DA ISOC in order to promote reliability and discourage misuse of this parameter.

The system state-of-charge mechanism introduced by the ISO appears to be another potential proposal aimed at reducing day-ahead buybacks due to insufficient state-of-charge. However, this approach also does not address the underlying BCR design issue, and DMM requests more information about this mechanism and how it is different than the minimum SOC constraint that was retired in 2023.

DMM supports enhancements to the storage default energy bid (DEB) and continues to recommend an hourly DEB for storage resources that reflects estimated intraday opportunity cost associated with future intervals and changing real-time conditions.[3]

DMM supports the ISO’s proposal to require storage resources to provide Master File parameters that reflect a qualifying capacity (QC) where the resource can discharge for four hours or more without expected power limitations (e.g., foldback).Further, DMM recommends the ISO introduce additional Master File parameters that allow for the additional energy within the resource to be available to the market during extenuating circumstances if the market or market operators were to need to access the stored energy.

Comments

DMM supports the ISO addressing storage bid cost recovery issues as a top priority. DMM continues to recommend redesigning storage BCR rules to assume no eligibility, and only add eligibility under specific situations where it is deemed appropriate and necessary to support market efficiency.[4]

DMM supports elimination of day-ahead BCR for storage resources

DMM supports the ISO’s proposal to eliminate DA BCR for storage resources. The ISO and stakeholders have not demonstrated that DA BCR for storage resources is necessary to support market efficiency. Further, the current DA BCR design can lead to unwarranted BCR payments and is susceptible to gaming. DMM recommends the same bottom-up approach be taken to establish rules for real-time bid cost recovery.

DMM continues to recommend that storage resources only be eligible for RT BCR under specific situations where deemed appropriate

Allowing storage resources to receive BCR for day-ahead buybacks due to insufficient state-of-charge removes their exposure to real-time prices and fails to incentivize efficient bidding for storage resources in the real-time. Many of the potential policy changes discussed by the ISO aim to minimize day-ahead buybacks due to insufficient SOC, but do not address the underlying issue that storage resources would still receive unwarranted BCR whenever these types of day-ahead buybacks do materialize.

As DMM has previously noted, allowing real-time bid cost recovery for day-ahead buybacks due to insufficient state-of-charge (SOC) can lead to inefficient bidding incentives and market outcomes.[5] DMM continues to recommend that storage resources only be eligible for RT BCR under specific situations where deemed appropriate.

If the ISO instead chooses to try to identify and address each different scenario that could lead to unwarranted RT BCR, DMM supports the consideration of proposals for limiting day-ahead buybacks due to insufficient SOC. DMM has found this to be the major driver of unwarranted BCR in the real-time market. Based on DMM’s monitoring over the last few years, DMM cautions that it will be challenging to identify and develop settlement rules to effectively prevent all the different causes of unwarranted BCR ex ante. In many cases, DMM has only been able to identify causes of unwarranted BCR ex post after detailed investigation of the interaction of market software features, market and operational conditions, and how settlement rules are applied.

DMM supports the ISO’s proposal to better incentivize accurate submission of day-ahead initial state-of-charge parameters. And DMM recommends strengthened tariff language to better define how the day-ahead initial state-of-charge should be used.

DMM supports the ISO’s proposal to address the current lack of incentive for storage resources to submit accurate DA ISOC parameters. While DMM supports the ISO’s specific proposals of requiring the submission of the DA ISOC in order to submit DA bids and making battery resources ineligible for RT BCR if their DA ISOC is sufficiently incorrect, DMM continues to recommend the ISO achieve this by removing RT BCR eligibility for day-ahead buybacks due to insufficient SOC. Even if resources submit accurate DA ISOC estimates, continuing to provide RT BCR for day-ahead buybacks due to insufficient SOC still results in inefficient bidding incentives and inefficient dispatch of storage resources in real-time.

Outside of the BCR context, DMM supports the ISO requiring the submission of DA ISOC for reliability purposes. DMM also supports strengthening the tariff language to better define expected use of DA ISOC, highlighting that it should be used to reflect a physical expectation of how the resource will be positioned in real-time at the beginning of the operating day, and explicitly state that it is not to be used solely for the purpose of effectuating a desired day-ahead schedule for economic purposes.

DMM requests more detail regarding the system state-of-charge mechanism mentioned in the presentation

The ISO’s presentation briefly introduced the concept of a system state-of-charge mechanism that would improve alignment between the SOC modeled in the day-ahead market and the telemetered SOC.[6] DMM’s understanding is the ISO is considering this mechanism as another potential avenue to minimize day-ahead buybacks for storage resources due to insufficient state-of-charge.

It is unclear whether this is the most efficient approach as it does not address real-time bidding incentives to manage SOC. DMM continues to recommend re-designing the BCR paradigm for storage resources so that they are properly incentivized to bid in a way that positions storage resources efficiently in the real-time. A system SOC mechanism does not address the underlying BCR design issues. DMM requests that the ISO provide additional information about this potential mechanism, and how it is different than the minimum state-of-charge constraint that was retired in 2023.

DMM supports enhancing the storage DEB to an hourly value that incorporates intraday opportunity costs

DMM has long recommended the storage DEB be refined to better incorporate real-time intraday opportunity costs. DMM has previously noted issues with the current storage DEB.[7] In particular, the DEB is static and therefore does not account for how intraday opportunity costs change across the day. In addition, the utilization of day-ahead prices does not account for differences that can materialize between the day-ahead and real-time and therefore may not be the most appropriate basis to estimate real-time intraday opportunity cost.

DMM continues to recommend the ISO implement a storage DEB that varies hourly so that it can incorporate the changing intraday opportunity cost associated with potential charge and discharge opportunities in future intervals.[8] An accurate hourly DEB would account for market conditions in future intervals when estimating the opportunity cost component of a particular hour. DMM recommends the ISO develop hourly DEBs that would allow the DEBs to be higher in the intervals leading up to the peak pricing hours, and lower in later intervals as intraday opportunity costs fall.[9]

In addition, a storage DEB that varies hourly would be necessary for the type of framework proposed by the California Energy Storage Alliance (CESA). DMM has discussed how storage resources may incorrectly be eligible or ineligible for BCR depending on DEBs that are incorrectly high or low.[10]

DMM recognizes that developing an approach that allows dynamic adjustments to battery DEBs in real-time could involve significant design and implementation complexities. Therefore, DMM recommends that the ISO and stakeholders pursue an incremental approach. A key software change that could be implemented expeditiously includes simply allowing real-time DEBs to vary for different time periods of the day, so that greater “headroom” is provided during the hours prior to the peak net load hours (12-17), compared to the level of “headroom” that is provided during the peak net load hours (18-22). A second key software change would be to allow real-time battery DEBs that are set based on day-ahead prices to be scaled upwards during the operating day based on actual market and system conditions.

Mitigation of storage resources should not be eliminated, as suggested by some stakeholders

While some stakeholders have suggested eliminating mitigation of storage resources, DMM does not believe this would be an appropriate market rule change. Storage resources should continue to be subject to market power mitigation where the potential for uncompetitive conditions exists. The establishment of more dynamic DEBs considering real-time conditions reduces the risk of mitigation to values that do not reflect real-time opportunity costs.

While the ISO’s presentation mentions that charging bids are subject to mitigation due to the need for monotonically non-decreasing bid curves, there are other reasons these bids are subject to mitigation including the flow effects of charging schedules on potentially uncompetitive constraints. Counterflow is provided when a resource forgoes charging. Uneconomically high bids to charge can worsen congestion by withholding this counterflow of foregone charging; therefore, mitigating those charging bids can relieve congestion by reducing uneconomic charging schedules.

DMM supports updating Master File characteristics for storage resources to reflect the stored energy available to the market to maintain full capacity of the resources across its operational range

The ISO is proposing that storage resources be “right sized”, whereby the parameters of storage resources provided to Master File reflect a qualifying capacity (QC) so that the resource can discharge for four hours or more without expected power limitations (e.g., foldback).^{^[11]} For resources in the CAISO balancing area, QC is determined by the California local regulatory authorities (LRAs). The proposal directs the LRAs to ensure that the QC of the resource is based on the SOC range that will not result in power limitations from physical (chemical) SOC constraints. The “right sizing” changes mean that in Master File the resource will only reflect the minimum and maximum continuous energy limit that will best ensure resources do not experience power limitations because of the resource’s SOC.^{^[12]}

The ISO states the change in resource QC will ensure consistency across all assets, minimize reliability and operational concerns, eliminate the need to use outage cards and be assessed resource adequacy availability incentive mechanism (RAAIM), and incorporate the power limitations into any future capacity constructs such as the unforced capacity (UCAP) adjustment to QC.^{^[13]} This change will effectively reduce the capacity and energy of storage resources that are available to the market, as well as reduce the QC that the asset owners will be able to sell to load serving entities as resource adequacy.

DMM has previously recommended the ISO create clear rules for storage resources experiencing power limitations in the extremes of their SOC.^{^[14]} DMM recommendations have emphasized that the rules must require that resources be assessed RAAIM and consider any future policies that would reflect capacity limitations to the market (e.g., UCAP). As a result, DMM supports the ISO requiring resources to only provide the operational characteristics of the resource in Master File that meet the capability of the resource. However, as discussed below, there are solutions to allowing access to the stored energy in the extremes of the SOC ranges to continue to provide grid services and reliability.

Reducing the operational range and adjusting the QC of some of the storage resources on the CAISO system will ensure the purchased resource adequacy (RA) of the storage resources can be expected to perform at their full power output when dispatched. As argued by REV Renewables, the reduction in the available SOC range may lead to adverse impacts on reliability, ratepayer costs, and storage owners.^{^[15]} DMM does not agree with this position, and would like to refer stakeholders to the resource adequacy modeling and program design (RAMPD) stakeholder initiative, and the importance of ensuring resources have a like-to-like resource adequacy (capacity) valuation to ensure fungibility within the RA market.^{^[16]}

REV Renewables argued the reduction in QC will result in reduced reliability without access to the additional energy, as well as increased RA price pressures as further RA would need to be procured.^{^[17]} A standard supply and demand analysis would suggest the reduction in RA supply will increase costs, however simultaneously the improved market modeling of the resources will lead to improved RA quality, and thus increased reliability of the QC on the system. Assuming no other changes in underlying conditions, this may ultimately lead to less demand for RA capacity in the long run, making the net effect on RA prices less clear.

DMM recommends access to energy in the extremes of the SOC should be available to the market in extenuating conditions. As proposed by REV Renewables, allowing access to the stored energy beyond the updated minimum and maximum continuous energy limits would require two modifications to Master File: (1) including a new maximum and minimum energy limit that extends beyond the range that is not power limited, but is still within the operating limits of the resource, and (2) a factor to adjust the Pmax of the resource to ensure power limits are not exceeded in the extended range.^{^[18]}

DMM has previously recommended the ISO develop additional Master File parameters to address power limitations at the SOC extremes.^{^[19]} To ensure there is consistent representation of the resource to the market, DMM recommends the ISO direct the LRAs to limit QC to the operational range that is not impacted by SOC limitations, and then allow resources to register their additional SOC and reduced power for extenuating circumstances if the market or system operators were to need the additional energy.

[1] Storage Design and Modeling Working Group on Outage Management, Uplift & DEB, and Mixed-Fuel & Distribution-Level Resources presentation, California ISO, November 12, 2025: https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Nov12-2025.pdf

[2] Comments on Storage Design and Modeling Working Group Presentation on September 29, 2025, Department of Market Monitoring, October 14, 2025: https://www.caiso.com/documents/dmm-comments-on-storage-design-and-modeling-sep-29-2025-working-group-presentation-oct-14-2025.pdf

[3] Comments on Storage Design and Modeling May 28, 2025 Presentation, Department of Market Monitoring, June 11, 2025: https://www.caiso.com/documents/dmm-comments-on-storage-design-and-modeling-may-28-2025-presentation-jun-11-2025.pdf

[4] Ibid.

[5] Comments on Storage Design and Modeling Working Gr oup Presentation on June 30, 2025, Department of Market Monitoring, July 16, 2025: https://www.caiso.com/documents/dmm-comments-on-storage-design-and-modeling-jun-30-2025-working-group-presentation-jul-16-2025.pdf

[6] Storage Design and Modeling Working Group, California ISO, November 14, 2025, p 56: https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Nov12-2025.pdf

[7] Comments on Storage Design and Modeling Working Group Session 2 and 3, Department of Market Monitoring, March 7, 2025: https://www.caiso.com/documents/dmm-comments-on-storage-design-and-modeling-working-group-sessions-2-and-3-mar-07-2025.pdf

[8] Comments on Storage Design and Modeling May 28, 2025 Presentation, Department of Market Monitoring, June 11, 2025: https://www.caiso.com/documents/dmm-comments-on-storage-design-and-modeling-may-28-2025-presentation-jun-11-2025.pdf

[9] Comments on Storage BCR and DEBs July 8, 2024 Workshop, Department of Market Monitoring, July 18, 2024: https://www.caiso.com/documents/dmm-comments-on-storage-bcr-and-default-energy-bids-july-8-2024-workshop-jul-18-2024.pdf

[10] Comments on Storage Design and Modeling Working Group Presentation on August 14, 2025, Department of Market Monitoring, September 5, 2025: https://www.caiso.com/documents/dmm-comments-on-storage-design-and-modeling-aug-14-2025-working-group-presentation-sep-05-2025.pdf

[11] Storage Design and Modeling Working Group on Outage Management, Uplift & DEB, and Mixed-Fuel & Distribution-Level Resources presentation, California ISO, November 12, 2025: https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Nov12-2025.pdf

[12] DMM notes that the minimum and maximum continuous energy limit ought to be “best” represented to the market to not impact power limitations due to the SOC of the resource. The use of best acknowledges there are many temporary factors that can lead to power limitations of the storage resource, such as cell imbalance. The scheduling coordinator should work with their operator to have the long-term limitations accurately reflected to the market. Whereas short-term limitations, such as maintenance and cell imbalances, should not be reflected within the limitations. These limitations will then be incentivized through interrelated policies such as RAAIM or UCAP.

[13] Storage Design and Modeling Working Group on Outage Management, Uplift & DEB, and Mixed-Fuel & Distribution-Level Resources presentation, California ISO, November 12, 2025: https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Nov12-2025.pdf

[14] Comments on Storage Design and Modeling Issue Paper and Straw Proposal on Outage Management, Nonlinearity and SOC Clarification, Department of Market Monitoring, May 23, 2025: https://www.caiso.com/documents/dmm-comments-on-storage-design-and-modeling-issue-paper-and-straw-proposal-on-outage-management-nonlinearity-and-soc-clarification-may-23-2025.pdf

[15] CAISO Storage Design and Modeling – Foldback/Non-Linearity Proposal, REV Renewables, November 12, 2025: https://stakeholdercenter.caiso.com/InitiativeDocuments/REV-Renewables-Presentation-Storage-Design-and-Modeling-Nov12-2025.pdf

[16] Comments on Resource Adequacy Modeling and Program Design Working Group, Department of Market Monitoring, March 13, 2025: https://www.caiso.com/documents/dmm-comments-on-resource-adequacy-modeling-and-program-design-working-group-mar-13-2025.pdf

[17] CAISO Storage Design and Modeling – Foldback/Non-Linearity Proposal, REV Renewables, November 12, 2025: https://stakeholdercenter.caiso.com/InitiativeDocuments/REV-Renewables-Presentation-Storage-Design-and-Modeling-Nov12-2025.pdf

[18] Ibid.

[19] Comments on Storage Design and Modeling Working Group Presentation on August 14, 2025, Department of Market Monitoring, September 5, 2025: https://www.caiso.com/documents/dmm-comments-on-storage-design-and-modeling-aug-14-2025-working-group-presentation-sep-05-2025.pdf

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

The Public Advocates Office at the California Public Utilities Commission (Cal Advocates) appreciates the opportunity to comment on the California Independent System Operator Corporation’s (CAISO) November 12, 2025 meeting on CAISO’s Storage Design and Modeling Initiative[1]

Cal Advocates provides the following comments on the November 12, 2025 meeting:

CAISO should coordinate with the California Public Utilities Commission (CPUC) to ensure the CPUC’s qualifying capacity (QC) accreditation method for energy storage is correctly informed, subject to an impact study on the resulting changes to the storage fleet’s overall QC value.
Cal Advocates supports CAISO’s proposal to eliminate Day-Ahead (DA) Bid Cost Recovery (BCR) for storage. CAISO should limit storage’s eligibility for Real-Time (RT) BCR to instances of exceptional dispatch and local market power mitigation (LMPM).
Cal Advocates supports a longer term, fundamental storage BCR redesign. However, CAISO should not delay the implementation of straightforward and effective intermediate solutions to protect ratepayers from unwarranted and excessive storge BCR.

[1] CAISO, Working Group on Outage Management, Uplift & DEB, and Mixed-Fuel & Distribution-Level Resources, November 12, 2025 (November 12 Workshop). Materials available at: https://stakeholdercenter.caiso.com/StakeholderInitiatives/Storage-design-modeling.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

Middle River Power LLC ("MRP") encourages the CAISO to modify the NGR model to address non-linearity and to allow market particiants to use the "Technical Limitations Not in Market Model" for outages to address non-linearity until the NGR model has been updated.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

NV Energy appreciates CAISO’s continued work toward ensuring market rules recognize the unique characteristics of storage resources and their participation in the market. NV Energy appreciates the meeting held on November 12^th and finds the proposals appropriate. However, NV Energy is concerned that the meeting was scheduled too short and did not provide enough time for detailed stakeholder discussion.

As stated in other comments, NV Energy requests that CAISO reserve the appropriate amount of time to review all the material presented and provide sufficient time for stakeholder discussion, and if needed, schedule separate stand-alone sessions to continue discussion on more complex issues.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E’s Primary Comments

Implementation Timeline: Strongly supports CAISO’s plan to reserve bandwidth in Q3 2027 for enhancements identified in this initiative. The timeline is realistic given the complexity of DAME and EDAM implementation and the significant enhancements expected after go-live.
State Of Charge: Endorses CAISO’s current SOC range approach and emphasizes adding SOC max and SOC min parameters to improve visibility under stressed conditions. Maintaining the minimum SOC constraint is essential to ensure reliable discharge capability and simplify battery operations.
Day-Ahead Uplift: Recommends delaying any decision to discontinue Day-Ahead BCR until at least six months after DAME go-live to confirm whether uplift remains necessary under the new market design.
Default Energy Bids (DEB): Calls for a comprehensive review of current DEB calculation methods to ensure they accurately reflect true opportunity costs. This analysis should address forecast accuracy, buyback cost treatment, multi-day cycling patterns, and the ability of batteries to provide services beyond energy.

Additional Comments

Supports consideration of AS re-optimization as a major market initiative after the successful implementation of DAME and EDAM.
Could support implementing REV Renewables’ proposal if CAISO confirms minimal resource impact and feasibility.
Agrees with CAISO’s clarification on why High Sustainable Limits (HSL) values are not auto-generated, recognizing resource flexibility and calculation complexity.
Provides detailed responses to Vistra’s questions regarding SOC management, physical constraints, and market horizon feasibility.
Requests a clearer definition of system SOC and its practical application.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

PGE appreciates the breadth of topics covered on Nov. 12 and sees the nonlinearity/foldback problem statement as an impactful near-term enhancement opportunity. The CAISO’s proposed exclusion of the lower and upper foldback regions could improve operational certainty but would understate resource-specific physical capability. PGE supports continued evaluation of approaches that improve upon the status quo while preserving the flexibility to optimize the entire range of a storage resource’s physical capacity.

Other topics, including SOC responsibility, uplift/DEB, and real-time AS enforcement, are important but not yet conceptually mature in the stakeholder community, and the learning process is still unfolding. Nonetheless, clarifying SOC roles, improving constraint transparency, and ensuring region-neutral DEB structures will support consistent storage behavior across the regional footprint. PGE will remain engaged in these upcoming discussions.

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV Renewables (REV) appreciates CAISO continuing discussions on this important initiative with its all-day meeting and allowing stakeholders to present proposals. As discussed in #3, REV is concerned with CAISO’s proposed near-term approach to address nonlinearity as it would negatively impact reliability, ratepayers, and storage owners by limiting energy available in the market. REV encourages further consideration of a solution, such as REV’s alternate proposal, to integrate nonlinearity into the market model in the near term to avoid these negative impacts. CAISO should aim to implement such a model solution for the Fall 2026 release given that this is also critical for EDAM storage resource integration.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

San Diego Gas and Electric (SDG&E) appreciates the opportunity to comment on the November 12 working group meeting for the Storage design and modeling (SDM) initiative. Our comments below focus primarily on feedback relating to nonlinearity, including the proposal from REV Renewable, as well as the uplift and initial/target SOC topics.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

Please see attached file.

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra provides our comments on the Storage Design & Modeling effort including the November 12 meeting below.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF appreciates the opportunity to comment on the Nov 12 working group session. Our comments below suggest a reprioritization of the topics based on discussions to date. For the more specific comments, we focus only on the topics discussed during the meeting; we will provide additional comments on the remaining items after the December session when those topics will be covered in more detail.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES supports the initiative's structured approach but is concerned about the pace of advancing longer-term solutions and urges the ISO to establish concrete timelines for the objective. The ISO should distinguish between technical improvements that can be achieved through business practice manual updates and policy decisions that require tariff or rule modifications. For decisions requiring formal approval, AES recommends establishing interim technical milestones to demonstrate progress rather than pursuing accelerated timelines that could compromise quality. Having said that, it is AES's position that the CAISO's approach proposal to address non-linearity cannot be implemented through a business process manual change.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA is concerned with the pace of this initiative and the inability to issue a proposal to implement longer-term solutions requested by stakeholders. Also, it is unclear how these comments can be incorporated into the December 4^th meeting and subsequent issue paper & straw proposal planned for mid-December.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates supports CAISO’s renewed focus on BCR and Default Energy Bids (DEB),[1] and its schedule to release an Uplift and DEB issue paper and draft straw proposal by December 15, 2025.[2] As discussed below, there are straightforward and effective approaches to protect ratepayers from unwarranted BCR. CAISO should proceed with implementation of these solutions.

[1] Cal Advocates recommended at the outset of the Storage Design and Modeling initiative that CAISO prioritize BCR and DEB reform. See Cal Advocates, Comments on Working group session 1 - Initial Discussion and BCR, DEB, and OMS, December 12, 2024, response to Question 1. Available at: https://stakeholdercenter.caiso.com/Comments/AllComments/2b83f24a-ad3a-4c29-aae1-b3997d81b383#org-e242b7ec-a271-4164-9b4d-2ddce44bd10d.

[2] CAISO, Working Group on Outage Management, Uplift & DEB and Mixed-Fuel & Distribution-Level Resources, November 14, 2025 (November 12, 2025 Workshop Slides) at 7. Available at: https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Nov12-2025.pdf.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

NV Energy finds the timeline reasonable.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E strongly supports CAISO’s proposed reserving implementation bandwidth for Q3 2027 for any enhancements identified in this initiative. The timeline is realistic given the complexity of DAME and EDAM implementation and the significant enhancements expected after go-live.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV is encouraged to see the schedule for most of the initiative coming to decision in 2026. However, given that the initiative has been in progress for nearly a year and is only at the straw proposal phase for a few parts and near the issue paper stage for others, while some issues have not even been discussed (e.g. Track 3), it is clear that more substantive work needs to be done in the next quarter to achieve this schedule.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

SDG&E thanks CAISO for the update and supports the initiative overview and schedule as described on pages 6-8 of the presentation. SDG&E strongly supports prioritization of this initiative in the roadmap and encourages CAISO to consider what (if any) near-term improvements to either improve the model or facilitate operational efficiencies, can be made in advance of the 2027 implementation timeline.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

The goal of this effort should be addressing (1) long-standing stakeholder concerns with storage operations since 2020 (and earlier) that we have been urging CAISO to address without success and (2) taking a holistic approach to reassess storage market operations and settlement rules in light of operational experience since 2020 as committed to following the Bid Cost Recovery and Default Energy Bid Enhancements emergency effort. We are concerned that the current process may not fully address the first set of issues, and we hope future discussions will provide a more holistic approach to these topics.

On the first goal of this initiative, Vistra requests the CAISO work with its technology team on robust solutions that can be implemented in 2026 to address the urgent operational issues. The issues that stakeholders have been advocating for are needed for improving storage operations include:

Outage Management System improvements
Outage rule clarifications on the newly emerging outages affecting storage as to which Nature of Work and what parameters & thresholds apply for reporting
Modeling solution for foldback
Real-Time Market Default Energy Bid changes to allow storage to reasonably reflect opportunity costs in real-time including the ability to seek reference level change requests as well as ensure placement is accurate under mitigation when the offer cap is raised above the soft offer cap
Co-located and hybrid resource rule clarifications

Vistra wants to see a proposal on the clear urgent issues above taken to the Governing Body and Board of Governors at the March board meeting for solutions #1-4. This would necessitate a straw proposal in December 2025 with options, revised straw proposal in January 2026, and draft final proposal in February 2026. While we understand the desire for additional time, we believe the timeline established for this initiative is appropriate given its scope and the duration of prior discussions.[1]

[1] SDM was launched on December 10, 2024 affording a roughly 14 month timeline between launch and Governing Body decision in March 2026. These issues have also been discussed in Energy Storage Enhancements, Price Formation Enhancements Bidding Rules Above Soft Offer Cap, and Storage BCR & DEB Enhancements that collectively made up 32 months. That amounts to with SDM affording 46 months or just shy of four years to stakeholder the issues and propose solutions.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

Overall, WPTF encourages CAISO to continue moving forward on elements of the policy where there is a clear and actionable path, specifically the DEB, long-term nonlinearity solutions, and outage improvements. At the same time, we urge CAISO to recognize where it may be more productive to reprioritize topics within this overall effort. In particular, we believe it is best to pause further discussions around bid cost recovery for several reasons as noted in response to question #5 below. We also believe it may be worthwhile to reset the discussions related to SOC management to ensure that the end product of this policy effort truly is a holistic review and evaluation of how storage resources are modeled and managed within the market. We discuss this in more detail in response to question #11.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES strongly supports ISO's focus on nonlinear representation as a foundational element of modern storage design, as current market models that assume linear discharge capability across all state-of-charge levels fundamentally misrepresent battery physics and operational constraints. However, AES does not support CAISO's current proposal to redefine the "maximum continuous energy limit" Master File field to align only with minimum RA qualification rules, which conflates CAISO's distinct operational concerns with the CPUC's resource adequacy planning framework. CAISO's data demonstrates that storage assets can charge and discharge in the foldback range in the CAISO market while operating at a reduced power rate. Yet, CAISO's proposal would remove this capability from market dispatch control. This approach risks removing up to significant energy (MWH) of available energy from CAISO's market annually, presenting concerning reliability and economic implications . AES urges CAISO to reevaluate its analysis and assumptions before implementing a proposal that would engineer market optimization to avoid deliberately accessing the foldback region. The REV Renewables proposal represents the correct approach: it maintains the full operational capability of storage assets—including the foldback region—available to system operators while accurately representing nonlinearity through dynamic foldback parameters.

AES emphasizes that RA programs accredit resources by reflecting their contributions to reliability, not as limits on maximum operational capability—solar resources with 10% qualifying capacity in November can produce at their full nameplate when physically capable. Similarly, storage resources must be allowed to access energy throughout their operational range, including the foldback region, when that energy is physically available and needed for grid reliability. CAISO's proposed approach would constitute CAISO-sanctioned physical withholding of available energy, which is particularly concerning during emergencies when every available megawatt-hour matters. AES strongly supports the adoption of REV's technical proposal, or any other proposal that integrates foldback parameters into the market model, to address the core nonlinearity while preserving operational flexibility and preventing artificial energy withholding. Separating CPUC resource adequacy validation from operational market parameters is essential to ensuring that regulatory accreditation requirements do not unnecessarily constrain market dispatch. AES urges the ISO to prioritize the REV approach and reject proposals that would restrict market access to otherwise available energy in the foldback region.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

The CAISO’s proposed path forward addresses two issues: (1) reflecting foldback in the CPUC RA qualifying capacity (QC) calculation; and (2) reflecting foldback in CAISO market optimization.

The CAISO should adopt CalCCA’s alternative RA accounting proposal for storage resources with foldback included in their PMin to PMax range if the CAISO puts forth a proposal in the CPUC’s RA proceeding. CalCCA understands that the CAISO plans to propose a QC methodology that accounts for foldback in the CPUC’s Rulemaking (R.) 25-10-003, on January 23, 2026. The CAISO’s proposed calculation would divide the amount of energy the resource can provide unaffected by foldback by four (for a four-hour battery). This will discount the RA counting for the resource for all hours it can be shown. This is not reflective of the nature of foldback and would overly constrain the RA value a resource can provide in the hour of greatest need. This is particularly important given the slice-of-day (SOD) nature of the CPUC RA system in which an LSE must demonstrate sufficient capacity to serve load in all 24 hours of the “worst day” of the month. Using an average rather than values that can be provided will unnecessarily discount resources in some hours in which the resource is available to reliably serve grid needs.

Instead, if the CAISO makes a proposal in the CPUC’s RA proceeding to account for foldback in the CPUC’s QC calculation, it should modify its proposed calculation to allow a resource to count for full capacity for three of the four hours and a derated amount in the fourth hour. Under the SOD framework, an LSE can claim the full amount of capacity for a single hour but may not need the full capacity in other hours. CalCCA’s proposed alternative calculation would result in a higher RA counting in the hour of highest need, and more accurately reflect the impacts of foldback on RA capacity.

The example below compares the CAISO’s proposal with CalCCA’s proposed alternative assuming a resource with a 25 megawatts (MW) nameplate, 90 megawatt hours (MWh) available, and 10 MWh unavailable due to foldback.

The CAISO’s proposed calculation
- NQC = 90MWh/4 hours = 22.5 MW
- SOD Showing: No greater than 22.5 MW in any hour
CalCCA’s proposed alternative
- NQC = 25 MW
- SOD Showing: MW in hour 1 + MW in hour 2 + MW in hour 3 + MW in hour 4 cannot exceed 90 MWh

Under CalCCA’s alternative proposal, the NQC will equal 25 MW (nameplate), and the total energy in all hours shown will not exceed 90 MWh. In this case, that means the resource can be shown for 25 MWs in hours 1 – 3, resulting in a total of 75 MWh and leaving 15 MW available for the fourth hour. The result is a maximum amount of 25 MW in any hour, limited by energy. Under this proposal, an LSE could show the resource for 22.5 MW in each hour and get the same result as the CAISO’s proposal but could also show up to an addition 2.5 MWs in three hours from the resource as long as the total showing does not exceed the resource’s energy limit. If the CAISO proposes derating a resource’s capacity value to account for foldback, it should do so using CalCCA’s alternative proposal and apply it only to resources whose PMax includes the foldback range.

This proposal will also work for resources that are not constrained by foldback. For example, if the resource has a 25 MW peak capacity and sufficient storage to provide 110 MWh, then the foldback never occurs and the energy limit is never reached meaning that the resource can be counted for 25 MWs in all four hours.

Market Optimization

The CAISO should prioritize the development of a Master File parameter as a market-based solution reflecting foldback in the market and ensuring known resource characteristics are modeled rather than reflected in a resource’s unforced capacity value. The CAISO proposes an interim and long-term proposal for addressing foldback in the market optimization. The interim proposal would result in the market optimization being unable to access the resources’ foldback range. As described in section 4, below, unnecessarily making energy in the foldback range unavailable to the market when foldback ranges are not static is a negative outcome for reliability, ratepayers, and storage owners.

Any interim approach should continue to allow the market to access the foldback range, when the resource is available within that range. A better alternative would be to maintain the status quo in the interim, in which storage resources reflect foldback ranges with outage cards and prioritize the CAISO’s long-term solution of a Master File parameter to reflect foldback in the market. CalCCA has previously advocated for the “Technical Limitations Not in the Market Model” Resource Adequacy Availability Incentive Mechanism (RAAIM) exempt outage card to be used and continues to support that approach for the reasons described in CalCCA’s September 5, 2025, comments.[1] More important than the type of outage card used in the interim, however, is prioritizing a Master File parameter as a market-based solution to reflecting foldback in the market and ensuring known resource characteristics are modeled rather than reflected in a resource’s unforced capacity value.

[1] https://stakeholdercenter.caiso.com/Comments/AllComments/a35d7182-e62e-4559-93c0-80ede736ceba#org-a3c4805c-db85-45ec-b58c-a9ccff090a32.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA does not support CAISO’s proposal. CAISO continues to conflate its operational and market model issues with resource planning process for capacity accreditation from local regulatory authorities. The CAISO must develop a market-based solution to enable the full operational capability of storage, including the foldback region, to be available to system operators.

This issue has been raised for over eight years since ESDER 2 Draft Final Proposal. CAISO erroneously concluded that foldback would not be an operational concern. Since there have been larger scale storage coming online in 2020 and later years, storage operators have raised that foldback impacts maximum output (Pmax) and minimum output (Pmin) as storage nears 0% state-of-charge (SOC) and 100% SOC respectively. CAISO should implement a modeling solution in Fall 2026 release and consider this improvement essential for EDAM. The stakeholder process needs to discuss implementation details developed by CAISO. Any RA capacity accreditation concerns should be clarified at the CPUC and not impact operations.

CAISO’s proposal to address storage non-linearity is simply to redefine its “minimum continuous energy limit” Master File field to align with minimum resource adequacy (RA) qualification rules. This conflates CAISO’s distinct operational concerns (like deviation risk) with the details of the CPUC’s RA planning framework. In effect, CAISO’s proposal has the potential to remove up to a TWh of energy out of its market and dispatch control per year, presenting concerning reliability and economic implications. To the extent that resources can produce power in hours beyond their minimum RA duration requirements, they must be allowed to do so. Generally, the RA program is not structured, and should not be construed to be structured, to disincentivize or discourage RA resources from offering more energy capability to the CAISO than its minimum RA qualifications.

CAISO’s core issue regarding storage nonlinearity, or foldback, revolves around an apparent attempt to reconcile the dispatch of lithium-ion battery energy storage systems within both operational requirements and the CPUC’s qualifying capacity (QC) methodology. This reconciliation is a inappropriate. RA programs often accredit resources at values less than their full capability, reflecting an average contribution to reliability. This is to ensure that load-serving entities procure more resources to meet overall reliability objectives, not to limit these resources’ participation in the market. For instance, CAISO sees many solar resources with a net qualifying capacity (“NQC”) value of 10.1 MW in November, but that does not mean that those resources should be limited to produce 0.1 MW if they are physically capable of producing more power.

CAISO proposes to limit the MWh value represented in the “minimum continuous energy limit” and “maximum continuous energy limit” Master File fields to only the MWh that is not affected by foldback. The result of this misguided proposal is that the market optimization will not access otherwise available energy within a storage resource’s foldback region. By engineering the market optimization to steer clear of the foldback region, CAISO is deliberately restricting the maximum operational use of the asset. This change would force the asset's dispatch to be limited to the simplified QC definition, which requires the resource to discharge at its QC level for four or more uninterrupted hours at an energy capability that is lower than its maximum performance. CESA believes this approach would effectively be CAISO-sanctioned physical withholding of available energy. Any physical MWh capability, even in the foldback region, should remain accessible to the system, especially during an emergency. CAISO’s medicine is worse than the disease because it artificially restricts the amount of energy that could be available to system operators.

For storage resources located in non-CAISO Western Energy Imbalance Market (WEIM) areas that are relied on to support their resource sufficiency evaluation (RSE) or their ancillary service needs this would unfairly shift a California centric decision to remove energy from the market onto entities externally comfortable with the reduced charging or discharge capability in this region.

Furthermore, CAISO’s supporting data does not demonstrate that the proposal is justified or that foldback energy is insignificant. CAISO analysis, which CAISO interprets as showing that most assets already represent only the range unaffected by foldback, fails to distinguish whether resources were actually discharged within their foldback regions. For instance, the data shows resources discharged to 0.1% SOC, but not whether those same resources were (or were not) actually discharged through their foldback regions to reach the 0.1% SOC. Therefore, this data cannot conclusively show the potential magnitude of the affected energy.

Reliability risks outweigh any claimed administrative simplicity, and CAISO must preserve access to physical energy. Even if CAISO anticipates that its proposal would not result in the loss of a material amount of available energy, the potential impact on reliability must be prioritized above all else. During a system emergency, which would a system operator choose: shed load or discharge foldback energy? The answer is clearly the latter, meaning that the full available energy—including that in the foldback region—must not be withheld from the market optimization.

Similar questions exist for when a non-CAISO WEIM entity would need that energy at the adjusted Pmax or Pmin levels to be used to pass its RSE where the WEIM participants should be able to choose whether storage’s available energy affected by foldback can be used to support its RSE. If a storage resource is not providing RA to a CPUC jurisdictional load serving entity, how should the resource’s maximum and minimum continuous energy limits be set in Master File? It is unclear to CESA why CAISO, as a market operator, would seek to limit the capabilities of storage resources artificially.

In addition, FERC found it unjust and unreasonable for CAISO to consider adding market values into Master File for parameters such as ramp rate even while the physical capability would be available for exceptional dispatches in its Commitment Cost Enhancements Phase 3 filing. It is unlikely that FERC would agree it is just and reasonable to require storage to physically withhold their maximum performance in physical parameters. CAISO cannot require a storage resource to register less than its maximum performance to be registered for a given parameter through a Business Practice Manual change.

In summary, CAISO should implement a nonlinearity modeling solution in Fall 2026 release and consider this improvement essential for EDAM. The stakeholder process needs to discuss implementation details developed by CAISO. Any RA capacity accreditation concerns should be clarified at the CPUC and not impact operations.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

CAISO presented a “path based on operational information and stakeholder feedback” at the November 12 workshop.[1] CAISO states that the CPUC should ensure that the QC value of storage resources is based on the resource’s state-of-charge (SOC) range that is unaffected by foldback.[2] Specifically, CAISO states that the CPUC should calculate the QC for storage by subtracting the minimum continuous energy limit from the maximum continuous energy limit, divided by 4 hours.

At the CPUC’s resource adequacy (RA) proceeding, CAISO raised a concern that the CPUC’s current QC calculation may not be aligned with the CPUC’s adopted methodology.[3] The issue that CAISO identified is that the CPUC may be using the CAISO master file data that measures continuous energy delivery where the output may vary over those hours. However, CPUC’s method intends to measure the minimum fixed output of a resource for 4 hours.[4]

CAISO’s recommendation to calculate the QC for storage by subtracting the minimum continuous energy limit from the maximum continuous energy limit, divided by 4 hours would effectively match the existing CPUC accreditation method to determine a storage QC because it uses the capacity output that can be sustained over 4 hours of consecutive dispatch.[5] CAISO concludes that “this approach would make it so that the market optimization will not access the foldback range.”[6]

CAISO should coordinate with the CPUC to ensure the CPUC’s energy storage accreditation method is correctly informed, subject to an impact study

CAISO should coordinate with the CPUC to ensure the CPUC’s adopted storage accreditation methodology is informed by the correct parameters. However, CAISO’s proposed fix to the misalignment between the CPUC’s QC methodology and the CPUCs use of CAISO master file parameters may cause significant adjustments to the QC values of storage in the CAISO fleet. The result could be a reduction in the amount of RA supply available for CPUC compliance. Correction of the error could cause load-serving entities (LSEs) to suddenly fail to comply with their RA requirements and make it necessary for these LSEs to procure replacement RA capacity.

To mitigate potential ratepayer harm and impacts to the value of storage on the grid, CAISO should conduct a study that quantifies monthly impacts to the net qualifying capacity (NQC) to assess the impacts that a fix to the potential error may cause. If the impact is significant,[7] CAISO and the CPUC and should consider either a phased-in approach or an alternative to CAISO’s solution. CAISO should present this monthly NQC impact study prior to, or along with, a CAISO proposal to adopt the change to correct the parameters that the CPUC uses to inform its QC accreditation methodology.

Adoption of the CPUC’s QC methodology to inform the CAISO market optimization may be costly and may not be enforceable if applied market-wide

CAISO also appears to suggest that the CPUC accreditation approach would inform the market optimization so that CAISO markets do not access energy in the foldback range.[8] However, it is unclear that reductions to storage energy and capacity availability would be cost effective or desirable. Reduced availability of storage energy and ancillary service products would likely cause wholesale market prices to increase because the overall pool of available energy and ancillary services products would be reduced. The net effect could be to increase costs to ratepayers beyond any benefits resulting from a reduction in unexpected storage foldback-caused outages. If CAISO intends to limit storage energy and capacity products to the market based on its proposed accreditation methodology, CAISO must first conduct a study to determine the impact this approach would have on the cost of energy and ancillary services. Stakeholders and CAISO may then compare the costs and benefits to determine if it is appropriate to proceed with any market offer limits.

It is also unclear whether CAISO intends to apply the CPUC’s QC methodology to the market optimization of all storage resources on the grid. CAISO’s tariff prevents it from enforcing a QC methodology on resources shown by the Local Regulatory Authorities (LRAs) that participate in the CAISO market, unless those LRAs do not use a QC methodology of their own.[9] In CAISO’s next proposal for this initiative, CAISO should clarify that its proposal would not affect the QC methodology for storage used by LRAs other than the CPUC. CAISO should also clarify that it will not decrease the ability of non-CPUC jurisdictional storage resources to provide energy and ancillary services to CAISO markets.

[1] November 12, 2025 Workshop Slides at 13-15.

[2] Foldback, also known as nonlinearity, is a reduction in charging or discharging capabilities of storage that occurs when the resource operates near 0% or 100% SOC. November 12, 2025 Workshop Slides at 9 and 13.

[3] “The Commission’s current QC calculation methodology may not align with its stated QC counting methodology for storage resources for two reasons. First, some storage resources have a minimum state of charge above zero megawatt-hour (MWh). Using only the maximum state of charge in the QC calculation does not recognize the inaccessible MWh below the resources minimum state of charge. Second, as some storage resources approach their state of charge limits, they can no longer be charged or discharged at their maximum level. Using the entire range between storage resources’ maximum state of charge and zero MWh may fail to recognize the state of charge range in which some storage resources are not capable of performing at their maximum level.” CAISO, Comments of the California Independent System Operator Corporation on Order Instituting Rulemaking, November 4, 2025 (CAISO OIR Comments) at 3; issued in R.25-10-003, Order Instituting Rulemaking to Oversee the Resource Adequacy Program, Consider Program Reforms and Refinements, and Establish Forward Resource Adequacy Procurement Obligations. Available at: https://docs.cpuc.ca.gov/PublishedDocs/Efile/G000/M586/K273/586273752.PDF.

[4] CAISO OIR Comments at 3.

[5] “Because all RA resources must be able to operate for four or more consecutive hours, the storage operator must submit to the CAISO an output level (in megawatts) at which the resource is capable of discharging for four or more uninterrupted hours; this is defined to be its PmaxRA, the maximum output that can be considered for RA calculations. Like fossil generators, the storage facility must then submit to physical testing by the CAISO to verify that it can be dispatched at this capacity. The QC will be equal to this PmaxRA value.” Decision (D.) 14-06-050, Decision Adopting Local Procurement and Flexible Capacity Obligations for 2015, and Further Refining the Resource Adequacy Program, June 26, 2014 at B-9; issued in Rulemaking (R.) 11-10-023, Order Instituting Rulemaking to Oversee the Resource Adequacy Program, Consider Program Refinements, and Establish Annual Local Procurement Obligations. Available at: https://docs.cpuc.ca.gov/PublishedDocs/Published/G000/M097/K619/97619935.PDF.

[6] November 12, 2025 Workshop Slides at 14.

[7] CAISO has undertaken some analysis already that “suggests most assets already represent only the range unaffected by foldback.” November 12, 2025 Workshop Slides at 16-17.

[8] November 12, 2025 Workshop Slides at 14.

[9] CAISO has previously stated:

The LRA-determined reserve margins and QC values, respectively, are inputs into CAISO’s RA processes, which include validating LSE RA plan submissions and determining resources’ NQC values. The CAISO tariff also specifies a default PRM of 15% and default QC criteria, which apply if LRAs do not specify QC values or reserve margins for their jurisdictional LSEs…

CAISO, Resource Adequacy Modeling and Program Design (RAMPD) Modeling and Default Rules (Track 1) Final Proposal, September 26, 2025 at 3. Available at: https://stakeholdercenter.caiso.com/InitiativeDocuments/Track-1-Final-Proposal-Resource-Adequacy-Modeling-and-Program-Design-Sep-26-2025.pdf.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP appreciates the CAISO’s attention to the minimum discharge requirement for an RA resource, which is 4 hours per day for 3 consecutive days. The CAISO’s clarification for standalone storage to maintain 4 hours of continuous discharge at a constant rate is reasonable. However, the CAISO proposal to simply not consider the portion of available energy in MWh in the non-linear range of the resource is unreasonable. For example, a 25MW/100MWh resource may be required to reduce to 20MW/100MWhto prevent the resource from being operating in its non-linear range but the CAISO is proposing to only allowi20MW/80MWh to be available to the CAISO. The additional 20MWh is not available to the CAISO market unless the CAISO chooses to access it via exceptional dispatch. MRP submits that the 4-hour requirement is a minimum and not maximum requirement for RA resources and therefore the additional 20MWh should be made available to the CAISO, just as non-duration limited resources are required to be available for all hours of the day.

MRP recommends the CAISO work to improve the NGR model to account for the nonlinearity so that the CAISO can access the full range of energy. In the meantime, the CAISO should allow the outages the CAISO proposes to address non-linearity to use the “technical limitation not in market model” nature of work.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

NV Energy does not support the CAISO proposal for non-linearity such that the market optimization will not account for the foldback range. NV Energy is particularly concerned that this proposal limits the total available capacity of a storage resource. While NV Energy does not participate in CAISO’s RAAIM program, this proposal may negatively impact entities passing the Resource Sufficiency Evaluation (RSE) test. The reduction of the charging capability of the resource would reduce the total charge available along with decreasing the ramp and capacity available for RSE tests.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E supports CAISO’s current approach of requiring SOC ranges that allow discharge at the RA maximum value until changes—such as those proposed by REV Renewables—are incorporated into the NGR model to enable dispatch within foldback ranges. REV’s proposal may offer a path to relaxing this restriction in the near term.

CAISO should prioritize implementing additional SOC range parameters (SOC max and SOC min) so that the physical minimum SOC is visible to operators under extremely stressed conditions for exceptional dispatch. While CAISO could consider relaxing its constraint on the maximum SOC range—since battery operators can constrain bids to avoid full charge awards when nearing maximum SOC in real time—maintaining the minimum SOC constraint remains essential. This guarantees discharge awards and simplifies operator management of batteries under stressed conditions.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

PGE views the nonlinearity update as a pivotal issue for SDM.

The CAISO’s proposed exclusion of the foldback region improves operations but inherently removes physically available energy from the modeled envelope. This approach is tightly linked to CPUC QC requirements for RA and may be overly conservative for a multi-BAA environment.

From a WEIM/EDAM participant perspective, operational modeling should reflect actual physical capability rather than CPUC RA-driven simplifications, especially as storage technologies and performance curves vary across BAAs. Eliminating the foldback region entirely reduces modeled flexibility footprint-wide and could unnecessarily constrict capacity during tight conditions.

Further, while PGE understands that the CAISO has verbally characterized the foldback proposal as a temporary solution, without a stated timeframe, PGE is concerned that this temporary measure could persist longer than intended.

PGE prefers an approach which accurately represents reduced power near SOC limits, rather than discarding that range. Such a design better aligns with EDAM scalability, regional neutrality, and market efficiency.

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV strongly opposes CAISO’s proposed solution for resources to only reflect the range unaffected by foldback Min/Max Continuous Energy Limit in the ISO’s Master File. CAISO’s proposal would cut 5-15% of storage energy available to sell in the market, leading to potential reliability impacts in the event of emergency where it’s needed, as well as significant lost revenue for storage owners. This lost energy will also be a loss for consumers with impact on cost of storage and potentially market prices as less energy is available. Additionally, the proposed limitation is discriminatory towards storage given that other resources have their physical restrictions integrated into the market model, such as ramp rates for thermal resources. This also infringes on a storage operators right per FERC Order 841 to self-manage their SOC through the participation model.

CAISO has two stated reasons for this proposal: 1) to ensure compliance with CPUC Qualifying Capacity Resource Adequacy (RA) definition of needing 4 hours of max continuous energy unaffected by foldback; and 2) CAISO Operations is increasingly concerned with infeasible dispatches and deviations due to foldback.

REV agrees on CPUC Resource Adequacy definition (reason #1), but as stated in our presentation this could be done with something like a “RA Max/Min Continuous Energy Limit” field in the Master File if needed. This new field would not be used in the market model. CAISO does not need to impact operational parameters to support compliance with CPUC RA. Additionally, implementing an operational restriction for CPUC compliance purposes could be discriminatory against EIM/EDAM entities with storage that do not need to comply with CPUC. An RA specific limit field would allow EIM/EDAM entities the option to use that field for their RA purposes or not.
REV does not agree that CAISO should make changes to the operational parameters in the CAISO market for foldback impacts. As discussed above, the proposed operational limitation is negative for reliability, consumers, and storage operators, and is discriminatory towards storage. REV understands that CAISO proposes this as an interim solution until the Track 3 “biddable SOC” model is implemented. However, if the schedule stays on track, that would mean waiting until mid-2027 decision and sometime after that for implementation (likely 2028 at best). This timeline would leave storage with restricted MWh for ~3 years, which is unacceptable.
- Additionally, if the solution would only be integrated into the new, yet-to-be-defined SOC model, then that would make the Non-Generator Resource (NGR) model obsolete. REV only supports future storage model development if the NGR model is also continued. The NGR model works very well for storage, with a few exceptions such as nonlinearity. Any new model takes time to implement and work out issues. Given this uncertainty, CAISO should not rely on a new model to fix this nonlinearity issue.

CAISO showed several bar charts to suggest that most assets already represent only the range unaffected by foldback. REV requests more information on how this data was calculated, such as what fields or operational values were used in the calculation and whether the resource was actually dispatched in the foldback range to reach the stated values. Additionally, while the data show that the discharge range may be already limited by storage operators, the charging range is not and limiting this range could negatively impact a storage resource’s ability to fully charge and offer its full RA capability to the grid.

To be clear, REV is very supportive of addressing the nonlinearity issue. In fact, REV raised this issue with CAISO and in stakeholder forums since 2020. However, the proposed near-term solution is not the answer.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

SDG&E cautions that CAISO’s proposed revised approach of using Master File continuous energy limits to exclude SOC ranges affected by foldback could create unintended consequences for system reliability and market efficiency. This approach reduces the operational capacity available to the system, results in physical withholding of energy, and increases energy and ancillary services prices. By embedding RA logic into resource operations, CAISO risks driving overbuild requirements for storage assets to meet compliance with constrained SOC representation, rather than leveraging their full market design capability. The proposed revised approach presented by CAISO during the working group meeting does not address these underlying issues. While SDG&E recognizes this revision is driven by CAISO’s desire to move swiftly to a consistent representation of these ranges for the purpose of preventing infeasible dispatches during operations, the cons of preventing the market from accessing available energy should point to an alternative short-term solution.

Further, SDG&E requests CAISO commit to developing and implementing a more durable solution as quickly as possible. It has been made clear in both CAISO’s analysis and stakeholder comments that addressing nonlinearity for storage resources is complicated by resource constraints, limitations of the market model, and alignment with the RA paradigm. However, it is critical to implement a proposal on nonlinearity that accomplishes the goals of improving market efficiency, reliability, and avoiding undue costs to ratepayers from reducing the available capacity of storage assets.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

CAISO should implement a modeling solution in Fall 2026 release and consider this improvement essential for EDAM. The stakeholder process needs to discuss implementation details developed by CAISO. Any RA capacity accreditation concerns, which Vistra shares, should be clarified at the CPUC and not impact operations.

This issue has been raised for over eight years since ESDER 2 Draft Final Proposal. We believe that the conclusion regarding foldback warrants further review, especially in light of recent operational data. Since there have been larger scale storage coming online in 2020 and later years, storage operators have repeatedly raised that the market is not capturing foldback impacts when maximum output (Pmax) and minimum output (Pmin) as storage nears 0% State of Charge (SOC) and 100% SOC respectively.[1]

Below is specific feedback on the presentation and discussion to help clarify the record.

CAISO presentation refers to Tariff sections that refer to “maximum sustainable performance”,[2] which is a requirement to register physical characteristics in Master File that are maximum representations of the asset’s physical performance capability applicable to each Master File parameter. When referring to maximum output the CAISO’s Tariff does not use the word “performance”. CAISO was not successful in seeking the ability to establish two parameters for a given physical characteristic – design and market-based – in ER18-1169. CAISO filed proposal to allow market values for various physical parameters such as maximum daily start-ups, maximum daily number of transitions, operational ramp rate values, operating reserve ramp rate values, and regulation ramp rate values with some limitations.[3] The physical, design values would still be available for exceptional dispatch purposes, which helped ensure that the maximum sustainable performance would be available under emergency needs even if the market relied on a less restrictive value.[4] FERC rejected what Bidding Rules Enhancements had stakeholder and was filed in the Commitment Cost Enhancements Phase 3 filing. FERC rejected the proposal to allow market-based parameters for elements such as thermal ramp rates because, “the use of market value parameters82 that do not reflect the full design capability of resources may have the effect of reducing the amount of capacity available to the market”.[5]

Since FERC found it unjust and unreasonable for CAISO to consider adding market values into Master File for parameters such as ramp rate even while the physical capability would be available for exceptional dispatches then Vistra finds it unlikely that FERC would agree it is just and reasonable to require storage to physically withhold their maximum performance in physical parameters. Any changes to registration requirements for storage resources be carefully considered to ensure alignment with established rules.

Storage assets should be registering their Maximum Continuous Energy Limit and their Minimum Continuous Energy Limit consistent with Tariff Section 4.6.4 to represent the maximum sustainable performance of those parameters, which is the maximum SOC that can be continuously held and the minimum SOC that can be continuously held. CAISO should then implement a market modeling solution that adjusts Pmax and Pmin once foldback range is entered.

The issues that CAISO raised concerning whether the Net Qualifying Capacity (NQC) today may result in a NQC that is representing higher MW than can be sustained over minimum duration of four hours is a separate issue from the market operation one being held. We believe the NQC rules are clear that the rule is that the Qualifying Capacity eligible to provide RA is only the PmaxRA that is based on the MW that can be sustained for four hours associated with full capacity deliverability status. It is also clear that the physical Pmax may exceed that PmaxRA amount for energy dispatches.[6] We believe the Commission’s decision was prudent in allowing storage to provide energy only capability up to its Pmax while limiting its ability to sell RA to the amount that can be sustained over four hours.

Vistra strongly supports that the QC rules at the CPUC should be updated to provide clarity on how the SOC input into this calculation is performed both under an ICAP and UCAP framework. Importantly, these clarifications do not require registering a narrower SOC physical range (minimum CEL and maximum CEL). The development of processes to better ensure compliance with existing CPUC rules should be held at the CPUC – the Local Regulatory Agency with the authority over its jurisdictional units’ QCs. A lack of clarity around existing QCs is best resolved through strengthening the Commission’s record on the subject and providing clarification in CPUC Docket 25-10-003. These changes should not impact market operations but limit the amount of storage that can count towards meeting RA requirements consistent with the LRA’s accreditation rules.

[1] This is due to the discharge current and charge current rates changing as the asset nears 0% SOC and 100% SOC.

[2] CAISO Tariff Section 4.6.4.

[3] ER18-1169 Transmittal Letter at Page 31.

[4] Id at Page 33.

[5] Order Accepting in Part, Subject to Condition, and Rejecting in Part, Proposed Tariff Revisions in Docket No. ER18-1169, Paragraphs 44- June 21, 2018.

[6] CPUC D.14-06-050 codifies storage operator’s right to submit maximum output (Pmax) greater than its maximum output eligible for RA at B-9: “Storage facilities may also submit a short-term maximum rated output to the CAISO, for dispatch purposes. This is defined as the resource’s Pmax, and is a value which could be greater than PmaxRA.”

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF appreciates the update and the overview of the CPUC’s plan to take up nonlinearity. We believe there is a clear path forward for addressing nonlinearity comprehensively in the CAISO market.

Given this direction, CAISO and stakeholders should focus its time and effort on developing a long-term, durable solution. Several viable modeling-based approaches have already been presented. We encourage the CAISO to advance those discussions while allowing resources to continue using RAAIM-exempt outage cards in the interim.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES strongly supports the REV Renewables presentation and its core principle that storage operators must access their full operational range to effectively manage state-of-charge and grid services while opposing CAISO's proposal to exclude the foldback region from market dispatch. The REV approach of integrating foldback parameters into the market model is in the right direction. Still, AES recognizes that implementation feasibility requires rigorous technical evaluation by CAISO's technology team to assess practical deployment and identify potential refinements. AES recommends that CAISO consider whether an hourly bid component approach might better capture the dynamic nature of foldback entry points, since the state-of-charge level at which storage resources enter the foldback region varies across operating conditions and battery chemistry, making static Master File fields potentially limiting. Hourly bid components would enable a more accurate reflection of changing foldback thresholds while also providing CAISO capability to assess resource adequacy compliance, such as whether resources are meeting their RA showing minimums. Suppose linear degradation modeling proves impractical or insufficient for operator dispatch optimization needs. In that case, AES recommends CAISO evaluate alternative approaches such as predetermined derate caps (e.g., capping dispatch at a percentage of Pmax when operating in the foldback region) rather than wholesale exclusion of foldback capability. The fundamental requirement is that CAISO must model nonlinearity within market optimization rather than continue with interim measures that fail to capture storage's actual operational capabilities and limit available energy to system operators. AES urges CAISO to prioritize technical feasibility assessment of REV's proposal and actively evaluate implementation refinements that maintain full energy access while accurately representing battery physics constraints.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA agrees with Rev Renewables that unnecessarily making energy in the foldback range unavailable to the market when foldback ranges are not static is a negative outcome for reliability, ratepayers, and storage owners. As stated in section 3, the CAISO should prioritize developing Master File fields for resources to reflect foldback ranges in the market model.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA supports accurate modeling of the foldback region in the market. This issue has been raised by multiple storage stakeholders in this effort. Based on the discussions/presentations to date, there may be a variety of simplifying market solutions that CESA is open to. It is essential that CAISO produce a timeline for all parties to understand which solutions could be implemented on what timeline.

REV Renewables’ proposal offers a constructive starting point for addressing foldback-region operations, and CAISO’s technology group is well-positioned to build on this foundation by assessing implementation feasibility and identifying potential enhancements. For example, while the concept is directionally sound, the level of SOC at which a storage resource enters the foldback region is dynamic, suggesting that an hourly bid-based value may be more practical than a static Master File entry.

Vistra previously presented similar proposals early on in this effort that aligned with Rev Renewables proposal presented at the November workshop indicating shared interest among storage to pursue similar types of solutions. Vistra also suggested CAISO’s technology group should assess whether a simplified implementation could be taken to allow the market to recognize foldback impacts in near term.

The REV Renewable and Vistra proposals should be evaluated by CAISO’s technology group to assess the implementation feasibility and identify improvements. For example, the level of SOC where a storage resource enters the foldback regions is dynamic. Thus, it may be better to implement this operational constraint through an hourly bid component or dynamic limit tool rather than in Master File. Also, the CAISO could use this hourly value to assess if RAAIM penalties would apply. For example, assume that the minimum SOC to meet the resource’s RA showing is 10 MWh. If the storage resource submitted 14 MWh as the point it enters foldback for a given hour, then the storage resource would be subject to RAAIM. Lastly, if CAISO determined that implementing a liner curve from the start of the foldback region is not implementable or does not meet the dispatch needs of operators, the CAISO could consider establishing a predetermined derate of the Pmax, for example cap dispatch at 10% of PMax when operating in the foldback region.

CESA recommends CAISO focus on how to implement a modeling approach for nonlinearity within the market optimization versus continuing to discuss interim measures because nonlinearity isn’t modeled. We look forward to CAISO bringing forward a proposal that can be implemented in Fall 2026 that allows the market to see the derated MW discharge capability and rerated (increased) MW charge capability without outage cards.

In summary, CAISO should implement a modeling solution in Fall 2026 release and consider this improvement essential for EDAM. The stakeholder process needs to discuss implementation details developed by CAISO. Any RA capacity accreditation concerns should be clarified at the CPUC and not impact operations.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

In prior comments, Cal Advocates supported CAISO’s proposal to continue the use of the Plant Trouble nature of work outage card to represent the impact of nonlinearity.[1] Cal Advocates also supported CAISO’s proposal to continue CAISO’s application of the resource adequacy availability incentive mechanism (RAAIM) to storage under foldback conditions.[2] Cal Advocates continues to support CAISO’s initial foldback proposal[3] as a near-term solution.

However, Cal Advocates also identified the need for a long-term, durable, and more effective approach to modify the representation of energy storage in the CAISO master file to incorporate the effects of foldback in the market model of storage dispatch. The values registered in the master file should be an accurate representation of the physical characteristics of the storage resource.

REV Renewables offers one such approach to incorporate foldback into the CASO market model. REV Renewables proposes that CAISO add several new parameters to the CAISO master file to model nonlinear storge foldback with a simpler approximate linear representation.[4] REV Renewables states that, unlike CAISO’s proposal for nonlinearity that would make the foldback SOC regions inaccessible to the CAISO market optimization,[5] the linear model would allow the CAISO optimization to dispatch resources within the foldback region, but at a reduced power capacity.[6] REV Renewables also indicates that the foldback region for storage resources is dynamic and can change on a daily or even an hourly basis. The dynamic nature of foldback could require battery operators to provide hourly updates to the foldback parameters in the RT market to maintain an accurate linear foldback representation.

REV Renewable’s general concept for representing foldback within the CAISO master file and optimization has merit, and CAISO should further develop the concept as part of a longer-term solution. However, Cal Advocates is concerned that a linear representation of nonlinear foldback would be inaccurate, particularly over a dynamic and potentially larger foldback range than initially anticipated. The potential need for hourly foldback parameter updates could significantly complicate implementation and market operations. Consequently, CAISO could face the same challenges as it does today if the updated optimization continues to issue infeasible schedules that fall within the foldback range. Robust stakeholder review, initial testing with historical data, and an iterative process of detailed design and testing is necessary before CAISO puts any solution into operation.

[1] Cal Advocates, Comments on Revised Straw Proposal on Outage Management Meeting on Aug. 14, 2025, September 5, 2025 (Cal Advocates September 2025 Comments), response to Question 1. Available at: https://stakeholdercenter.caiso.com/Comments/AllComments/a35d7182-e62e-4559-93c0-80ede736ceba#org-5948f86f-6979-42b0-b490-b0f75556dea7

[2] Cal Advocates September 2025 Comments, response to Question 1.

[3] CAISO, Revised Straw Proposal on Outage Management Topic Group, August 8, 2025 (Revised Straw Proposal) at 11. Available at: https://stakeholdercenter.caiso.com/InitiativeDocuments/RevisedStrawProposal-StorageDesignModeling-OutageManagement-Aug082025.pdf.

[4] REV Renewables, CAISO Storage Design & Modeling – Foldback/Non-linearity Proposal, November 12, 2025 (REV Renewables Proposal) at 4. Available at: https://stakeholdercenter.caiso.com/InitiativeDocuments/REV-Renewables-Presentation-Storage-Design-and-Modeling-Nov12-2025.pdf

[5] REV Renewables Proposal at 2.

[6] REV Renewables Proposal at 8.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

NV Energy is interested in REV Renewables’ proposal and is supportive of a proposal to integrate foldback into the Market Model. NV Energy would like to know more about the feasibility of implementing REV Renewables’ proposal into the CAISO market.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E could support an initiative to implement REV Renewables’ proposed solution if CAISO agreed that it would require relatively minimal internal resources. The proposal enables market dispatch of batteries with foldback ranges, based on Master File-registered foldback range values and by adding constraints within the real-time NGR optimization. This would have the benefit of giving CAISO access to feasible dispatches of batteries in the foldback range without requiring batteries to submit derates, improving both market efficiency and potential storage utilization, and eliminating the risk of RAAIM penalties for batteries offering their foldback range. These changes appear to not introduce new decision variables — particularly integer variables— so they should not negatively impact solution time or convergence.

Successful implementation would depend on market participant (i.e., battery operators) acceptance of this approach as a near-term solution to the foldback issue and requires updates to the Master File (which CAISO has indicated it is receptive to making, allowing both RA continuous energy limits and physical continuous energy limits of batteries visible to operators) along with seemingly straightforward model changes, such as additional charge and discharge constraints.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

PGE appreciates the REV proposal and sees value in representing nonlinearity through capability-based constraints rather than eliminating the foldback region entirely. As an enhancement to REV’s approach, PGE proposes evaluating a SOC-percentage formulation instead of fixed MWh thresholds.

Using SOC% to define foldback start points would better accommodate normal variations in available energy and dynamic Pmax (such as module outages, inverter derates, and ambient-driven performance changes) without requiring frequent updates to absolute MWh values. A SOC%-based structure scales naturally with changing conditions, while retaining the simplicity of the REV proposal. PGE is open to further exploration of this conceptual refinement with CAISO staff and regional stakeholders.

PGE believes that the REV proposal would allow the market to reflect physical capability more accurately across external BAAs without introducing complexity into the CAISO’s market model. As presented, PGE is directionally supportive of, and preferential towards, the REV proposal.

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV appreciates the opportunity to present our solution to account for foldback in the market model. This would limit infeasible dispatches and allow the high/low ends of state of charge to be accessed (fixing CAISO’s reason #2 as discussed above).

REV chose a linear representation a way to very closely mirror nonlinearity because it assumed it would be easier to implement. However, if CAISO prefers nonlinear model and that has a similar implementation timeline, REV is open to this and other adjustments to this proposal. One item that is important is the ability to update nonlinearity limits in the Real Time. These updates may be done easier if the limits are represented as a percentage rather than a MWh level. Again, these are details that could be discussed in the stakeholder forum with CAISO as we understand what model improvements are possible in the near-term.

REV requests CAISO provide an update on the feasibility of REV’s or a similar solution to integrate into the market model, including an implementation timeline. If such a solution can be done in the Fall 2026 release, REV suggests that no other interim solution (e.g. continuous energy limits or outage cards) is necessary.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

SDG&E agrees with REV’s assertion that CPUC RA QC validation rules should not influence operational limits within CAISO’s market design, as these are distinct frameworks and should remain separate. Based on our initial review, REV’s proposed approach would be a preferred alternative to CAISO’s revised proposal, as it appears to keep the RA and operational parameters separate while addressing the operational impacts of nonlinearity in the market dispatch. As part of the next set of meeting materials for the SDM initiative, SDG&E requests that CAISO provide an evaluation of the implementation effort and resources required for this proposal to inform stakeholder feedback and prioritization of this approach.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

CAISO began discussing with storage community its views around foldback back in 2016-2017 in Energy Storage and Distributed Energy Resources (ESDER) Phase 2 process. In its Draft Final Proposal the CAISO evaluated whether it would prioritize resources to include changes to the Non-Generator Resource (NGR) model due to reduced MW throughput limitations, which it determined not to do so because it was the “ISO’s understanding that these specific SOC based MW throughput limitations are, for the most part, removed by the battery manufacturer and battery management and control systems”.[1] Importantly, this conclusion was arrived to well before there was sufficient storage online to gain operational experience to prove out this assumption. Just like all emerging technologies, there comes a time after sufficient resources achieve commercial operations where the CAISO should evaluate operational data to help inform needed enhancements. CAISO agreed on November 12^th that it is observing operational challenges that now necessitate resolving this issue so that the feasibility of market awards to storage can be assured.[2]

The urgency from the stakeholder community to address this issue has been high since 2020-2021 when various stakeholders began raising the issue again with urgent calls to address the operational challenge. Vistra has proposed potential solutions previously such as Master File resource-specific fields that would provide either a % modifier to Pmax as function of telemetered SOC or a Pmax MW value as function of SOC for the discharge current rate curve and similar but inverted data for the current discharge rate.[3] Rev Renewables presented a similar implementation approach at the November 12^th meeting. Vistra has also presented ideas that could simplify the approach significantly by either adopting a generic assumption for foldback that could be applied to all storage resources based on historical performance. We have also floated the dynamic limit tool as another option to reflect changes to Pmax and Pmin as result of foldback. We recognize that other technical solutions may exist to reflect the impacts of foldback on Pmax and Pmin that CAISO’s technology team may be able to better envision.

With the onboarding of new Balancing Authority Area (BAA) outside of California it is increasingly imperative that the CAISO cure what has been a known market design issue since at least 2020 as Extended Day-Ahead Market (EDAM) committed and leaning BAAs will be joining the day-ahead market with sizable portions of storage. See below DMM’s 2024 annual report showing the storage fleet outside of California ISO with Portland General Electric (~275 MW), Public Service Company of New Mexico (~600 MW), LADWP (~275 MW), and NV Energy (~800 MW).

Source: 2024 Annual Report on Market Issues and Performance.

The ability to manage storage in the CAISO’s market is swiftly becoming an area neutral, regional issue not a California centric issue. Vistra wants to see this issue resolved with a technical solution that CAISO’s technology team is willing to implement in 2026. We should not let perfect be the enemy of good.

The next step is that CAISO’s technology team needs to assess what the feasible implementation solutions are that can be deployed by Fall Release 2026. We look forward to CAISO bringing forward a proposal that can be implemented in 2026 that allows the market to see the derated MW discharge capability and rerated (increased) MW charge capability without outage cards. This will allow stakeholders to respond to what is feasible in 2026 with substantive feedback on whether meets the needs or not.

In summary, CAISO should implement a modeling solution in Fall 2026 release and consider this improvement essential for EDAM. The stakeholder process needs to discuss implementation details developed by CAISO. Any RA capacity accreditation concerns, which Vistra shares, should be clarified at the CPUC and not impact operations.

[1] CAISO ESDER 2 Draft Cinal Proposal, Pages 30-31, available at https://stakeholdercenter.caiso.com/InitiativeDocuments/DraftFinalProposal-EnergyStorage_DistributedEnergyResourcesPhase2.pdf.

[2] CAISO SDM November 12 presentation at slide 12.

[3] Vistra presentations on July 26, 2021 on slides 4-6 available at https://stakeholdercenter.caiso.com/InitiativeDocuments/VistraPresentation-EnergyStorageEnhancementsWorkingGroup-Jul26-2021.pdf; April 13, 2022 on slide 2 available at https://stakeholdercenter.caiso.com/InitiativeDocuments/Vistra-Corp-Presentation-Energy-Storage-Enhancements-Apr13-2022.pdf; December 11, 2024 meeting on slides 9-10 available at https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-VistraCorp-Storage-Design-and-Modeling-Dec-11-2024.pdf; January 23, 2025 meeting on slides 4-5 available at https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Vistra-Storage-Design-Modeling-Jan-23-2025.pdf. Note, these are the major presentations and other comments on the topic were also submitted.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES supports the guiding principle that storage must provide reasonable assurance of the ability to reflect willingness to charge/discharge, even when mitigated, and this is critical for managing state-of-charge to meet schedules throughout the operating day. AES recommends that the ISO develop a storage-specific make-whole payment design that distinguishes between revenue shortfalls caused by CAISO market design constraints and those resulting from bidding behavior inconsistent with actual system conditions, ensuring that compensation mechanisms don't inadvertently incentivize economically inefficient bidding. AES strongly supports modifications to storage default energy bids that enable resources across the entire market footprint to reflect intertemporal opportunity costs in their bids, recognizing that a storage resource's value depends on when and how it charges and discharges relative to forward prices and grid conditions. Effective DEB modifications must allow storage resources to represent their full operational range and update bids in real time to reflect changing state-of-charge conditions, opportunity costs, and grid requirements, as static bids cannot accommodate storage's dynamic operational economics. Storage DEB designs must be fundamentally different from conventional generation approaches, explicitly accounting for storage's unique role in arbitrage, grid services, and SOC management rather than fuel cost minimization. These guiding principles should guide detailed DEB design work to ensure storage resources can effectively participate in CAISO markets while supporting grid reliability objectives.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA supports the CAISO eliminating opportunities for strategic bidding to inflate BCR payments. CalCCA agrees with the stakeholder-supported, principle-based approach in which negative revenues attributed to market algorithms or CAISO action may warrant uplift, and negative revenues attributed to bidder behavior may not warrant uplift.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA supports developing a storage make-whole payment design that differentiates between a shortfall caused by the CAISO market and a shortfall caused by bidding behavior inconsistent with system conditions.

CESA supports changes to the storage DEB to enable storage resources across the entire market footprint to reflect intertemporal opportunity costs in bids.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates agrees with CAISO’s guiding principles for the Uplift and DEBs topic group. CAISO indicates that stakeholders broadly agree on two fundamental principles: 1) BCR is not warranted when it results from operator action, and 2) BCR may be warranted when it results from CAISO action, including exceptional dispatch, multi-interval optimization (MIO), and local market power mitigation (LMPM).[1] A limited group of stakeholders suggest that market constraints such as the ancillary service SOC constraint should be included among CAISO actions that warrant BCR.[2]

In prior comments, Cal Advocates recommended that CAISO eliminate DA and most RT BCR, except for RT BCR in warranted circumstances that result from exceptional dispatch, MIO, and LMPM.[3] In response to analysis from CAISO’s Department of Market Monitoring (DMM),[4] Cal Advocates amends its recommendation to instead limit RT BCR only to instances of exceptional dispatch and LMPM, as discussed in response to Question 7.

[1] November 12, 2025 Workshop Slides at 28 and 49.

[2] November 12, 2025 Workshop Slides at 49.

[3] Cal Advocates, Comments on Mixed-Fuels & Distribution-Level Resources Discussion Paper and June 30, 2025 working group meeting, July 16, 2025 (Cal Advocates July 2025 Comments), response to Question 2. Available at https://stakeholdercenter.caiso.com/Comments/AllComments/9167b4eb-0cc2-4eef-ae2c-9de975861f85#org-c0be0451-0cb6-451d-845e-b6b5693a7677.

[4] DMM, Comments on Storage Design and Modeling Working Group Presentation on September 29, 2025, October 14, 2025 (DMM Comments) at 1. Available at: https://stakeholdercenter.caiso.com/Comments/AllComments/c9903a4c-a900-47d2-b362-51c768a52e73#org-491a4bfb-f7b6-4ec6-afdc-b46f6d2c8bc5.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

NV Energy finds the guiding principles for the DEB reasonable and NV Energy supports the use of the DEB for all resources in the WEIM, which is currently not available. NV Energy believes that these principles should be further developed to ensure that all resources receive equal treatment. For example, there is a component that is unique to EIM entities that these bids are critical to passing the RSE tests in the WEIM. An inaccurate DEB used during mitigation could dramatically affect the charging of a storage resource leading to a higher loss due to shortages at peak times.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

No comment.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV supports the guiding principles related to uplift and DEB. REV agrees if the storage operator actions led to inefficient dispatch it should not be allowed for uplift, while inefficient dispatch due to the market model should be allowed for uplift.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

SDG&E supports CAISO’s guiding principles and thank CAISO for their responsiveness to stakeholder feedback, as the principles are reflective of the challenges described by stakeholders on this topic.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra requests pausing further work on uplift until the impact of the upcoming emergency changes can be assessed and until market outcomes under EDAM/DAME can be analyzed.

As a general principle, make-whole payments, or uplift, for net shortfalls experienced across an operating day due to the market optimization are inherent and healthy aspects of an organized market. There are bid components that are not represented in $/MWh such as commitment cost offers that drive the optimal outcome but are not priced into the energy clearing price that are elements of the optimal cost-minimized solution that just are not recovered through energy clearing prices necessitating make-whole payments. There are also costs that are not always priced into the energy clearing prices for the cost associated with maintaining security constraints in the market that may result in what appear to be uneconomic results but are in fact optimal because respecting a physical constraint or respecting a market constraint at a specified penalty price is the nature of running a security constraint market. In all these instances, we agree with stakeholders that it is foundational to Energy & Ancillary Service markets that the market provides uplift payments to all resources when the market outcome results in net shortfalls. The only exception to this foundational rule is when a market participant is taking actions to drive that outcome (i.e., in control of the market result for that interval). If the market participant is taking action to intervene in the economic solution to drive an outcome outside of economics then it should not be made whole for that is not the optimal outcome and instead driven by the SC intervention.

The trade-off between whether CAISO may eliminate or severely restrict uplift resulting from its market decisions hinges on whether that decision was driven by the market and its constraints or driven by SC driven decisions. If CAISO wants to eliminate uplift, then it needs to cede control over storage operations instead of shifting the responsibility onto storage Scheduling Coordinators. Otherwise, CAISO should cease this discussion on uplift as it will be making a policy decision to maintain strict control over storages’ operations through the mitigation and SOC management constraints it enforces.

Finally, uplift is important to send signals to the market operator for when there is an element of its design that may be undermining the overall efficiency of the market pricing where shifting that cost out of non-priced adjustments or out of commitment costs (e.g., Constrained Output Generator) into the energy clearing prices help to minimize uplift covered by Load Serving Entities. Vistra believes the data CAISO is showing does not indicate an urgent need to restrict uplift payments but instead indicates an urgent need for us to holistically reassess market design choice to enforce constraints that are driving uneconomic results. Decisions to protect Ancillary Service awards at any cost by the market and consequently load while allowing storage to avoid AS no rescission payments for their unavailability is a policy decision. This policy decision challenges Storage SCs ability to manage their asset and unfairly shifts the cost of our SOC management onto load serving entities. Observing uplift that may be reduced through changes to the market designshould be incentivizing CAISO to reassess whether it should continue to overly constrain storage not incentivizing it to explore whether to eliminate/restrict uplift.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF would like to reiterate the context for the current BCR discussion. More than a year ago, CAISO and stakeholders undertook an expedited process to revise the BCR calculation for storage resources in response to DMM concerns. During that process, stakeholders agreed that the existing BCR framework was not designed with storage resources in mind and that a broader, holistic re-evaluation of an uplift mechanism for storage should follow.

To date, the discussion has not moved toward that holistic review. Instead, it has focused on incremental modifications to the existing framework, such as eliminating day-ahead BCR and narrowing the conditions under which real-time uplift might apply. We are concerned that this narrow framing is preventing the group from stepping back and evaluating, from first principles, what a storage-appropriate make-whole framework should look like.

WPTF continues to believe it is fundamental for the market to provide make-whole payments to all resources. Make-whole payments exist precisely for rare situations where market revenues are insufficient to cover appropriate costs. The fact that certain factors trigger uplift only infrequently is not a reason to eliminate BCR, rather it is evidence that the mechanism is functioning to provide cost coverage for exceptional circumstances.

Given the significant changes coming to the day-ahead market in six months, including entirely new products and constraints, with no operational experience regarding how these will affect storage scheduling or cost recovery, we strongly believe the prudent path forward is to gain additional experience with the new products and market before discussing any more changes to the BCR framework for storage resources. Additionally, the newly approved BCR calculation changes have not yet been implemented. Once these changes are implemented the expectation is that the magnitude of BCR to storage resources will decrease and the concern raised by DMM will be addressed, thus further support pausing discussions on BCR for the interim.

For these reasons, WPTF recommends that CAISO pause all further discussion of BCR until:

The modified BCR calculation has been implemented and we have real-world experience with its performance; and
DAME and EDAM have gone live and the market has gained experience under the new design.

At that time, WPTF would support re-initiating a discussion on a truly holistic make-whole framework for storage resources, one that begins by understanding the purpose behind make-whole payments and then design a mechanism that aligns with the purpose. The discussion should not start with the current framework and simply explore how to modify or constrain it (e.g., eliminating day-ahead BCR or adding more real-time eligibility requirements).

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES recommends that CAISO prioritize developing a real-time make-whole payment design for storage before pursuing day-ahead market modifications, as CAISO's own benefit-cost analysis data demonstrates that day-ahead benefit-cost ratios for storage resources are very low, indicating limited economic value from day-ahead uplift mechanisms. Current day-ahead uplift mechanisms inadequately address storage-specific cost structures, as storage economics are primarily driven by real-time arbitrage opportunities and grid service provision rather than by day-ahead scheduling certainty. AES recommends that after CAISO develops a comprehensive real-time make-whole payment design that appropriately compensates storage for real-time dispatch constraints and opportunity costs, the initiative should then sequence day-ahead market modifications to support and align with the real-time mechanism rather than developing day-ahead solutions in isolation. This sequencing approach would ensure coherent policy design, in which day-ahead mechanisms reinforce real-time economics rather than creating conflicting incentives or redundant compensation mechanisms. AES supports the principle that initial state-of-charge levels should be determined by prior market outcomes rather than ISO manipulation, and recommends that real-time make-whole payments focus on compensating for genuine operational constraints rather than on enforcing particular SOC levels through uplift penalties. By establishing real-time mechanisms first, CAISO can then design day-ahead provisions that enable storage resources to position optimally for real-time opportunities while maintaining grid reliability objectives.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA reiterates its October 13, 2025, comments.[1] Specifically, the CAISO’s solution should adhere to the principle, rather than institute a blanket elimination of day-ahead BCR, unless the CAISO can demonstrate all cases of day-ahead BCR are driven by scheduling coordinator action rather than CAISO market or operator action.

CalCCA directionally supports the CAISO’s proposal to require the submission of the day-ahead initial State of Charge (SOC) parameter within a certain accuracy range to be eligible for BCR. In general, scheduling coordinators (SC) should be responsible for accurately reflecting their resources’ characteristics rather than relying on a default value. CalCCA supports adopting a mechanism to incent submissions within a pre-defined accuracy range, though it does not take a position on which proposed mechanism should be adopted among the CAISO, California Energy Storage Alliance, and Vistra Corp. (Vistra) proposals.[2] If an SC does not select a value despite the requirement to do so, then the CAISO should include a default value. If the default value is outside the accuracy range, the resource should be ineligible for uplift.

[1] https://stakeholdercenter.caiso.com/Comments/AllComments/c9903a4c-a900-47d2-b362-51c768a52e73#org-57fb586b-0cfd-4b02-a180-1b0262593a0f.

[2] Storage Design and Modeling, Working Group on Outage Management, Uplift & DEB and Mixed-Fuel & Distribution Level Resources (Nov. 14, 2025) (CAISO Presentation), at Slide 45.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

The CAISO committed to performing a holistic review of the uplift storage resources need to be made whole for CAISO driven market outcomes, and to date this effort has fallen short of that commitment. To progress the conversation, CESA recommends CAISO focus on starting that holistic review with a focus on real-time market. CESA recommends developing a real-time make-whole design for storage. As CAISO has shown, day-ahead BCR is very low for storage resources. This data supports focusing on real-time issues. Yet, CAISO continues to focus on the day-ahead market. After developing a real-time make-whole payment design, the initiative should then focus on changes to the day-ahead market that will support and align with the real-time make-whole payment design. Given the upcoming Day Ahead Market Enhancements (DAME) changes it is also premature to propose a day-ahead uplift policy until sufficient experience is gained under the DAME enhancements to identify whether Imbalance Reserves and the new envelope equations may lead to more frequency in the day-ahead market requiring uplift.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates supports DMM’s recommendation that CAISO should eliminate storage DA BCR, unless CAISO identifies specific instances of warranted storage DA BCR.[1] DMM indicates that CAISO has not identified any such instances.[2] Consistent with CAISO’s guiding principles for Uplift, CAISO should not make BCR payments to storage to offset negative DA storage revenues that occur due to operation action.

In prior comments, Cal Advocates supported CAISO’s proposal to require storage operators to submit an initial DA SOC parameter instead of defaulting to a zero initial SOC.[3] More accurate market parameters provide benefits to ratepayers from resultant improvements in market efficiency. DMM subsequently commented that a more effective approach is to provide stronger incentives for storage operators to submit accurate SOC parameters.[4] Currently, storage operators are not incentivized to submit accurate SOC parameters because they have assurance that BCR payments will offset any negative revenue resulting from insufficient RT SOC that triggers buy-backs of DA schedules.[5] Cal Advocates agrees with DMM that strong incentives are a more effective approach to improve market efficiency. CAISO should eliminate RT BCR that shields storage operators from non-performance due to insufficient SOC as an incentive to submit accurate SOC parameters.

[1] DMM Comments at 2.

[2] DMM Comments at 2.

[3] Cal Advocates, Comments on Uplift & DEB, State-of-Charge Management, and Mixed-Fuel and Distribution-Level Resources Meeting on Sep 29, 2025, October 14, 2025 (Cal Advocates October 2025 Comments), response to Question 2. Available at: https://stakeholdercenter.caiso.com/Comments/AllComments/c9903a4c-a900-47d2-b362-51c768a52e73#org-92173f73-939c-427e-8ac6-33156be8f2f8.

[4] DMM Comments at 2.

[5] DMM Comments at 2.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

NV Energy supports the ISOC parameter if this policy is extended to the EDAM.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E recommends postponing any decision to discontinue Day-Ahead BCR until at least six months after DAME go-live. While CAISO’s analysis of Day-Ahead Uplift makes a strong case for eliminating day ahead BCR under the current market regime, the implementation of imbalance reserve and reliability capacity products in the DAME initiative could change this assessment or the need for uplift.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV continues to support keeping Day-Ahead uplift eligibility, particularly until EDAM and its related new products, such as imbalance reserves, is rolled out and CAISO and participants are able to understand its impact. While REV agrees Day-Ahead uplift will likely be minimal, it should not be eliminated right before these significant market changes.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

Regarding initial SOC, SDG&E supports exploring methods to improve accuracy by either refining default SOC values or incentivizing SCs to provide accurate SOC information within reasonable thresholds. These requirements should remain forward-looking and account for evolving market features—such as imbalance reserves and storage envelope equations—that could make current accuracy thresholds impractical in the future. At this point, SDG&E does not take a position on tying SOC accuracy to uplift eligibility due to the challenges outlined by stakeholders regarding real-time SOC management (i.e., exceptional dispatch, market power mitigation, etc…), but we are supportive of further discussion on this topic.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

CAISO should pause discussions on day-ahead uplift as these discussions in the face of implementing drastic changes to the day-ahead market via EDAM and Day-Ahead Market Enhancements are premature. It is imperative that we observe Integrated Forward Market results after EDAM/DAME go-live to determine whether to make Limited Energy Storage Resources whole in day-ahead or not. The addition of Imbalance Reserves and envelope equations are two elements that are likely to drive significant changes to day-ahead market outcomes compared to today.

Vistra responds below in #8 to Initial SOC as Initial SOC is a real-time challenge not day-ahead.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

See response to #5 above. Additionally, WPTF would like to reiterate that the purpose of these BCR discussions was to take a holistic approach to rethinking make whole payments for storage resources. Adding elements such as ensuring initial day-ahead SOC is within a certain threshold of real-time SOC and eliminating day-ahead BCR is viewed as making a modification to the existing framework and is not furthering the original intent of this effort. Furthermore, eliminating day-ahead BCR simply because there is minimal BCR in the day-ahead market is not a valid policy reason to eliminate a market mechanism that ensures resources are able to recover costs submitting in the market. We need to keep in mind that there are some significant changes coming to the day-ahead market and we have zero experience at this point as to what impact those changes will have on storage resources. Lastly, eliminating day-ahead BCR for one resource type is viewed as discriminatory. We have provided examples in previously submitted comments highlighting examples where under the exact same conditions a thermal resource would receive BCR but not a storage resources.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES supports CAISO's continued development of the real-time make-whole conceptual framework, which provides a coherent structure for evaluating whether storage resources are bidding in line with real-time operational conditions. The accuracy of the real-time default energy bid is critical to this framework's effectiveness, as inaccurate real-time DEBs will result in excessive make-whole payments that compensate for market design failures rather than genuine operational constraints. AES recommends that, rather than implementing hourly DEB updates for each interval, CAISO establish a more efficient approach that allows system operators to dynamically adjust storage default energy bids when they identify that real-time system conditions during the net load peak will be materially different from day-ahead forecasts. Under this approach, when CAISO determines that system conditions warrant adjustment, the revised DEB should apply across all operating hours through the net load peak period rather than on an hour-by-hour basis, reducing administrative complexity while maintaining alignment with actual grid conditions. This method enables responsive bid adjustment without requiring frequent real-time updates, while ensuring storage resources have appropriate default bids that reflect genuine operational conditions. AES emphasizes that the real-time make-whole framework will only function effectively if real-time DEBs accurately reflect storage opportunity costs and grid conditions, making improvements in DEB accuracy essential to reducing inappropriate make-whole payments.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA supports a real-time uplift approach aligned with the principle discussed in section 5, above. The data provided by the CAISO and the Department of Market Monitoring clarifies the magnitude of out-of-merit dispatches resulting from the multi-interval optimization (MIO) and the comparison of net revenues under the MIO and a counterfactual no-MIO scenario. The overall BCR methodology for storage should consider MIO out-of-merit dispatches and provide resources make-whole payments if they experience net losses over the day. However, a specific uplift payment for MIO out-of-merit dispatches without consideration of net losses over the day, as suggested by some stakeholders, is unnecessary and unsupported.

Instances of MPM may warrant uplift if a resource bids to preserve its output until later in the day, but the bid is mitigated, causing the resource to be dispatched when it otherwise would not have been. On the other hand, instances of MPM may not warrant uplift if the resource is rightfully mitigated to avoid the abuse of market power. For the reasons described in section 11, the CAISO should not cease local MPM for storage assets as a means to eliminate the need for a real-time uplift mechanism because MPM plays a role in protecting ratepayers from the exercise of market power.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA supports continued development by CAISO of the real-time make-whole conceptual framework. Since the conceptual framework determines if a storage resource is bidding consistent with real-time conditions based upon the real-time DEB, an inaccurate real-time DEB will result in higher make-whole payments. CESA does not believe an hourly DEB is necessary. Rather, if CAISO identifies that system conditions during the net load peak will be higher than planned for in the day-ahead market, the storage DEB should be increased and applied to all hours though the net load peak. The reference level change request process could also be explored for making changes intra-day.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

In the September 2025 Storage Design and Modeling workshop, CAISO provided an analysis of storage operation under the RT MIO process that shows RT prices in binding intervals are generally consistent with advisory interval prices, and that CAISO RT storage schedules in the binding interval are comparable to storage schedules in the advisory intervals.[1] Several stakeholders, including Cal Advocates, requested that CAISO conduct an analysis of the overall impact of MIO on storage revenues that includes both revenue gains and revenues loses due to MIO.[2]

In comments on the September 2025 workshop, DMM provided an initial analysis of the MIO’s impact on storage revenues based on the historical operation of 130 storage resources between October 2024 and September 2025.[3] DMM’s analysis compares actual market settlement in the fifteen-minute market (FMM) including MIO, versus a counterfactual that removes MIO. DMM’s analysis shows that the MIO process provides overall benefits to storage resources that exceed the cost of uneconomic dispatches, with a conservative estimate of 24% average higher daily net revenues with MIO than without MIO across all resources.[4]

DMM’s initial analysis is subject to limitations, including consideration of only the FMM and the potential to underestimate MIO benefits. The analysis does not consider other storage limitations that could yield counterfactual schedules that may have been infeasible in the RT market, which would overestimate the supposed counterfactual benefits.[5] However, DMM’s analysis provides a strong initial indication that the MIO provides higher storage revenues than would be achieved without the MIO. CAISO should extend DMM’s analysis to the five-minute RT market and work to resolve any additional limitations of the analysis.

Pending a comprehensive analysis of the net impacts of MIO, Cal Advocates recommends that CAISO eliminate RT storage BCR related to MIO. CAISO’s continued payment of RT storage BCR for MIO unreasonably burdens ratepayers with excessive and duplicative costs for which storage resources are evidently already well compensated.

[1] CAISO, Working Group on Uplift & DEB, SOC Management, and Mixed-Fuel & Distribution-Level Resources, September 29, 2025 at 17. Available at: https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Sep-29-2025.pdf.

[2] Cal Advocates October 2025 Comments, response to Question 3.

[3] DMM Comments at 3.

[4] DMM Comments at 3.

[5] DMM Comments at 3.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

NV Energy agrees that more analysis is needed. While NV Energy found the DMM’s comments and assessments informative, NV Energy believes there is no distinction whether uneconomic awards are due to the Multi-Interval-Optimization (MIO) or if they could be related to constraints like the End-of-Hour bid constraint. While this biddable constraint is useful it can lead to more instances of uneconomic awards than the MIO.

NV Energy also believes that there are some existing mechanisms that compensate for these uneconomic situations in the form of Real-Time Imbalance Energy (RIE). This calculation should be revisited to possibly clarify these scenarios.

While Ancillary Service State-of-Charge Constraint (ASSOC) does not apply to the WEIM, NV Energy believes in the fundamentals of this constraint and should be used for accurate SOC deliverability.

NV Energy’s initial thought is that the proposed DEB framework with Nth highest Maximum Import Bid Price (MIBP) for opportunity cost as well as price-based opportunity costs could be beneficial.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

No comment.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV continues to encourage Real-Time DEB adjustments that can better reflect changing real-time constraints and opportunity costs. Locking in the DEB to day-ahead prices is not reflective of real-time conditions, such as transmission constraints or outages that can lead to mitigation and often results in inefficient storage dispatch.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

SDG&E supports CAISO’s guiding principle that real-time uplift should apply only to negative revenues caused by ISO actions or market algorithms, not to outcomes driven by resource bidding behavior. DMM’s analysis shows that OOM dispatch, while seemingly infrequent when compared against every hour of the day, is concentrated around early morning and early evening net peak hours - periods of heightened system stress where uneconomic outcomes can have significant reliability and cost implications. Because of this, OOM dispatch due to MIO remains an important consideration in the real-time uplift framework.

Additionally, while charging mitigation appears to occur infrequently, its magnitude can be substantial. When mitigated bids prevent resources from charging to meet future obligations, the resulting shortfalls can create severe operational challenges and undermine market efficiency. SDG&E believes any real-time uplift design must account for these potentially high-impact scenarios to ensure resources are not penalized for conditions beyond their control.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

See above response. To continue discussing the need for real-time market to allow Storage Scheduling Coordinators to have the ability to reflect in their energy bids its real-time opportunity costs including from not being able to meet a day-ahead schedule unless real-time conditions would incent the change in dispatch. CAISO should stop its focus on real-time uplift and conditioning eligibility to receive real-time uplift based on how well the SOC is managed whether by the SC or the market to align with the bid-in initial SOC. CAISO should focus on establishing a real-time Default Energy Bid that will allow SC’s to manage their SOC in real-time. Vistra is skeptical that it will be able to do so and continues to recommend that CAISO acknowledge the challenges with SOC management in real-time market given the limited market horizon and deactivate its mitigation of LESR.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

See response to #5.

8. Provide your organization’s comments regarding the notion of establishing a form of System SOC target or constraint, including your perspective on how the SOC target should be established and the relationship this target or constraint would have with market products.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES is cautious about establishing a formal system state-of-charge target or constraint mechanism, preferring instead an approach that enables storage resources to respond dynamically to real-time conditions rather than conforming to predetermined system-level mandates. AES recommends that CAISO prioritize publishing detailed system-state-of-charge information to inform better all market participants of changes between day-ahead SOC expectations and actual real-time system conditions. By providing transparent, real-time SOC visibility, storage resources can more accurately reflect changing system needs in their energy bids without requiring complex enforcement mechanisms or targets that may create unintended market distortions. This market-transparent approach enables storage operators to make economically efficient bidding decisions aligned with actual grid conditions while preserving operational flexibility.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA is weary of having a system SOC target or constraint. As part of CESA’s conceptual framework, CESA recommended the CAISO publish information regarding system SOC to better inform market participants of changes between day-ahead SOC expectations and actual real-time SOC. This will enable storage resources to better reflect real-time conditions in their energy bids.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates does not have comments at this time.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

NV Energy is concerned with how the System SOC would apply to WEIM entities. NV Energy could not locate details describing how the System SOC would work. NV Energy has found that the resource SOC has worked well and believes the System SOC could be another constraint that could lead to uneconomic awards that would be viewed as MIO issues.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E cannot support or oppose this proposal without a clearer definition of system SOC and its practical application. Specifically, PG&E needs clarity on what system SOC means, how its minimum and maximum limits are determined, and how it can be effectively employed to manage the portfolio of storage in CAISO.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV defers comment on this issue at this time.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

SDG&E does not have a position at this time on establishing a form of System SOC target or constraint as we still do not fully understand the proposal. CAISO asserts that a system SOC concept would align with existing stakeholder proposals on initial SOC submission, and therefore the ability to qualify for make-whole payments under certain proposed uplift frameworks. While inclusion of an SOC submission requirement may be fairly straightforward, the proposal lacks the detail required for stakeholders to make any such assessments. It is unclear to SDG&E what how this target/constraint would be submitted and how it would impact system SOC visibility. SDG&E requests further information and clarification on this topic.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra requests clarity from CAISO on the role of the initial State of Charge (SOC) bid and the ISO expectations on how it should be managed by SCs. Today, SCs submit an initial SOC forecast at 10AM T-1 for the next day’s real-time market. However, actual end-of-day SOC may diverge from this forecast due to real-time conditions such as transmission outages or unexpected local constraints. These dispatch changes are not the fault of SCs, but rather the result of responding appropriately to real-time market signals.

The key policy question is whether CAISO expects storage to:

(a) prioritize real-time market needs, even if this causes SOC to differ from the forecast, or
(b) manage operations to align with the initial SOC bid, regardless of real-time conditions.

To make the issue clearer here is an example. On 11/25 the CAISO runs IFM for 11/26. At 10am on 11/25 a storage SC submits an initial SOC bid for its expectation based on current real-time market expectations for the end-of-hour in HE24 that it expects will be used as the initial condition in the first RTM run for 11/26. However, if for example a transmission outage occurs after the IFM market close leading to a constrained load pocket that the storage is located in driving increased discharge awards in e.g., HE16-HE20 greater than it had expected based on fundamentals at 10AM (HE11) then its SOC telemetered to set the initial condition in the first RTM run for HE1 this is not the SC’s fault but due to being willing to respond to market signals in real-time.

The initial SOC discussion is an issue that requires us to have a higher-level policy discussion on whether storage should be responding to real-time market needs or if the expectation is they bid in real-time to reflect a need to move its SOC at end-of-day into alignment with what it had forecasted at 10AM that morning. If CAISO deactivates market power mitigation for storage, SCs will be better able to manage real-time dispatches toward their bid-in SOC. In lieu of deactivating then CAISO will need to establish a real-time mitigated price that allows the SOC management such that the SC can manage the SOC to bring its forecasted SOC in alignment with its bid if that is CAISO’s directive.

Vistra believes sending incentives for storage to force alignment with its forecasted SOC is not good market design. Further, we have reevaluated and recommend removing the System SOC concept from the current scope to focus on more pressing issues.

In cases where reliability concerns arise due to SOC misalignment, CAISO operators already have sufficient tools—such as exceptional dispatch—to manage the situation. We encourage the CAISO policy team to coordinate with operation training teams to see if there can be improved procedures to ensure this risk is being monitored and managed through exceptional dispatches.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF is open to further discussing this concept, however, as noted in response to #11 below this should be part of the holistic discussion first that tries to establish at a policy level how we want storage resources to be managed within the market.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

No additional comments. Please see previous response.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

See previous response.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

In prior comments, Cal Advocates recommended that CAISO develop a dynamic RT storage DEB to accurately represent hourly or sub-hourly changes in RT storage opportunity costs.[1] Accurate representation of RT opportunity costs though the DEB is necessary to ensure accurate LMPM and ensure that CAISO efficiently dispatches storage when the LMPM mitigates bids. An accurate RT DEB would also lessen the need for RT BCR because the mitigated bid would be more likely to result in an in-the-money RT schedule. Moreover, if CAISO uses the RT DEB in a BCR framework to compensate storage for out-of-merit-dispatch, the RT DEB must accurately capture dynamic RT opportunity costs, rather than reflect a static DA DEB value.

[1] Cal Advocates September 2025 Comments, response to Question 8.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E request thorough analysis of whether current methods for calculating real-time and day-ahead battery DEBs accurately identify the true opportunity cost. Specifically, does the “fourth highest hour” approach correctly capture a battery’s real opportunity cost in these markets? If not, PG&E suggests examining potential causes, including:

use of a forecasted price that is significantly different from the actual fourth highest price
Incorrect inclusion of costs of day ahead buyback in the opportunity cost calculation?
Errors from using an energy-only calculation when batteries can offer other services in addition to energy (especially relevant post-DAME go-live)
Lack of consideration for multi-day values or nonstandard cycling patterns beyond a single-cycle pattern.

PG&E requests this analysis at both the portfolio and individual battery level, with the latter analysis appropriately anonymized to protect commercial strategies.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

PGE supports continued refinement of the storage DEB to improve representation of intertemporal opportunity cost and real-time system conditions. At the same time, DEB structures should remain broadly applicable across EDAM BAAs and avoid relying on California-specific assumptions. A balanced, region-neutral approach will help ensure consistent and efficient storage participation across the footprint.

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

As discussed in #7, REV supports modifications to the real-time DEB to better reflect real-time conditions, which are often location specific.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

No comment.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra appreciates renewed focus on advancing the discussion, building on the principles outlined beginning in December 2024 to a speedy policy resolution in Q1 2026.

CAISO does not apply market power mitigation to all resource types. Some are exempt due to their size because it is found less credible that they would be able to exert market power (e.g., small storage) and others are exempt because the CAISO acknowledges it would be very difficult to estimate opportunity costs associated with its use (e.g., participating demand response). Vistra has observed challenges with CAISO's ability to estimate LESR's incremental costs and as such exempting from mitigation at least in real-time may be appropriate.

Efforts to estimate LESR’s opportunity costs given how dynamic its use limitations are and the limited view the real-time market horizon sees have been fraught. CAISO has not shown evidence that the storage DEB is producing DEBs that align well with what the opportunity costs of these resources. Nor has CAISO shown evidence of how the placement of storage in the supply stack changes when mitigation is applied.

The crux of the issue is that storage need to be able to submit bids that relative to other resources’ allow them to be evaluated as either higher priced (needing to be reserved) or as trade-offs (indifferent to discharging storage or hydro) at the appropriate point in the supply stack.

We are skeptical that CAISO can develop a DEB methodology that both (1) would allow the market result to approximate what could be produced if the market horizon was 24 hours and (2) would place storage in the right place in the supply stack. Further, this effort has failed to hold a high-level policy question on “where is the right place in the stack”.

While we do not want to presuppose the policy discussions on where in the stack storage should sit from an incremental cost perspective, we will add a few brief principles.

Storage’s charging bids should not be mitigated, and of course to respect increasing monoticity the discharge bids should be increased by at least the registered Variable Operations & Maintenance values or a deminimis value to approximate some indifference between modes.
Storage should not be deployed sooner than hydro or participating demand response resources also valued based on opportunity costs due to a mitigated price that approximates a lower opportunity cost than other opportunity cost resources.
Storage should not be deployed to support off-system sales (i.e., exports) due to a mitigated price making it appear as if it is willing to sell off its SOC prematurely.

It is possible modifying the Hydro DEB methodology to only include the short-term opportunity cost and gas bid floor appropriately valuing an intra-day use limitation may offer improvements over the current storage DEB methodology. The Hydro DEB multiplier was established based on analyzing next day hub prices, which have changed since its establishment so a narrow improvement helping both hydro and storage if these approaches are aligned would be to make the multiplier be a value updated on a periodic basis to ensure it continues to achieve its goal when designed.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF supports modifying the storage DEB so that it better reflects expected opportunity costs across the day in both the day-ahead and real-time markets. This is an area where CAISO should continue making progress and we believe there are some viable options that have been presented so far. A more accurate DEB will help resources better manage their SOC and could naturally alleviate several of the concerns that currently manifest through BCR, reducing the need for uplift while ensuring appropriate cost recovery.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES appreciated PG&E's presentation as an excellent example of collaborative stakeholder input that informs CAISO's policy roadmap and demonstrates the value of diverse perspectives in shaping long-term market design evolution. AES supports continued engagement with utilities and other major market participants like PG&E, as their operational insights and strategic perspectives strengthen the technical foundation for implementing the Storage Design and Modeling initiative recommendations.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA appreciated PG&E’s presentation. The PG&E presentation was an excellent example of the type of discussion that should occur as part of the CAISO’s annual policy initiative roadmap process. What is the collective stakeholder vision of the CAISO market design evolution? However, it is unclear how CAISO expected the PG&E presentation to move forward resolution of issues being discussed in the Storage Design and Modeling initiative.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

CAISO and stakeholders have long recognized that the current BCR framework that was developed for thermal resources is inappropriate for storage given storage’s unique operational characteristics.[1] Cal Advocates supports fundamental, long-term BCR reform that recognizes storage does not have the key characteristics of thermal resources that necessitate BCR, as noted by the Federal Energy Regulatory Commission (FERC).[2]

Cal Advocates appreciates PG&E’s and the Vistra Corp.’s (Vistra) presentations of their conceptual ideas for fundamental BCR reform. Cal Advocates recommends that CAISO and stakeholders continue to explore these ideas in an ongoing effort to develop market rules that maximize storage’s potential to increase efficiency and reliability to the benefit of both ratepayers and market participants. Cal Advocates also agrees with Vistra’s verbal comments that it would be helpful for CAISO to provide stakeholders with more information about the relative difficulty of implementation for various potential reforms.[3]

However, PG&E’s and Vistra’s proposals at this late stage in the Storage Design and Modeling initiative should not delay CAISO’s implementation of straightforward and effective measures to protect ratepayers from unwarranted, excessive, and duplicative BCR payments. CAISO should move swiftly to eliminate DA BCR and limit eligibility for RT BCR to instances of exceptional dispatch and LMPM.

[1] CAISO, Storage Bid Cost Recovery (BCR) and Default Energy Bid (DEB) Enhancements Stakeholder Meeting on Issue Paper & Straw Proposal (IPSP), August 5, 2024 (August 5, 2024 Workshop) at 12. Available at: https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Bid-Cost-Recovery-and-Default-Energy-Bids-Enhancements-Aug-5-2024.pdf.

[2] August 5, 2024 Workshop at 19.

[3] Nov 12, 2025 Workshop Recording at 2:02:50. Available at: https://www.youtube.com/watch?v=H9CKq95bnb4.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E supports consideration of AS re-optimization as a major market initiative after the successful implementation of DAME and EDAM. However, PG&E emphasizes that this effort requires a comprehensive stakeholder process that extends to all market participants — not only those involved in the storage enhancements discussions.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV supports PG&E’s proposed enhancements of CAISO AS reoptimization. REV agrees with the benefits laid out and that this solution would improve real time market efficiency and reduce the need for bid cost recovery. REV encourages further discussion of this proposal, though understands it may be more of a mid-term solution.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

SDG&E appreciates PG&E’s proposal to reform ancillary services optimization as a strategic enhancement to CAISO’s market design. Providing resources the ability to buy back day-ahead AS awards through decremental bidding could improve operational flexibility and reduce uneconomic outcomes caused by rigid constraints. This approach has the potential to minimize OOM dispatch and better align real-time decisions with system needs, particularly as storage penetration grows.

The integration of immense quantities of variable energy resources and energy storage systems suggests that we have significant opportunities to re-optimize existing products, which could yield meaningful improvements to economic outcomes and dispatch efficiency throughout the market. However, SDG&E understands real-time AS re-optimization to be a very large, longer-term project. As such, SDG&E recommends this be considered later in this initiative, after near-term priorities and incremental fixes are addressed.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra really appreciated PG&E’s presentation. This is the type of big picture information that is critical for stakeholders and CAISO staff to connect the dots on. CAISO does not perform full AS co-optimization in real-time market, which is why the CAISO market protects the day-ahead AS awards through the Upper Economic Limit and Lower Economic Limit even if it results in real-time market energy awards. The other heuristic interventions that PG&E raised further moved the discussion on why it is critical for CAISO to take a step back and ask itself whether it has a challenge managing storage that receive AS awards, or if it is that its market is no longer well situated for protecting AS awards in real-time given the changing mix of the fleet. We really appreciate PG&E trying to help connect the dots on how the SOC management actions that CAISO desires would likely be unneeded with AS co-optimization. As discussed, AS co-optimization also addresses price formation concerns that improve the price signal in the real-time market such that if storage’s energy bids are allowed to reflect opportunity costs, then the market results will be better tuned to meet the markets collective needs while effectively managing storage. We request the CAISO reprioritize AS co-optimization in Price Formation Enhancements effort and respectfully, we do not support AS co-optimization requiring nodal AS.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF appreciates the presentation made by PG&E. We believe this also highlights the need to ensure the discussions taking place in this policy effort start from a heuristic level and try to understand all the implications of market features on storage resources as that will help narrow down the root cause of some of the challenges storage resources are facing.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES appreciated Vistra's presentation and recognizes the importance of understanding how storage resources experience constraint modeling across CAISO's multiple market clearing processes (IFM, RUC, STUC, FMM, and RTD). AES supports Vistra's emphasis that CAISO should fulfill its commitment to provide comprehensive documentation of all constraints enforced on storage dispatch and state-of-charge calculations across these market timeframes, as this transparency is essential for storage operators to understand dispatch outcomes and bid appropriately. AES recommends that CAISO prioritize delivering this constraint documentation as a near-term deliverable that will directly support the Storage Design and Modeling initiative's technical work on nonlinearity representation and operational parameter refinement.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA appreciates Vistra’s presentation and acknowledges the challenges with managing use-limited storage resources in the CAISO market. However, CalCCA does not support exempting storage resources from local MPM under Vistra’s proposed self-management option. MPM is a critical component of the CAISO’s market design to prevent suppliers from exerting market power, maintain competitive market outcomes, and ensure just and reasonable rates for customers. While there are other resource types to which MPM is not applied, these resources are: (1) not fully integrated into the CAISO market (e.g., certain investor-owned utility-run load reduction programs); (2) called upon only in emergencies (e.g., reliability demand response resources); (3) bid but based on the value to load, with bids being struck primarily where other marginal cost based supply has run out or load is willing to curtail at a price lower than the marginal resource (e.g. proxy demand response); or (4) should be subject to MPM pending the development of a DEB (e.g., hybrid resources). The CAISO should therefore seek to enhance the tools and methodologies used to manage storage resources in the market and provide uplift payments without exempting the technology from MPM.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA appreciated Vistra’s presentation. While CESA advocates for a holistic review of the current constraint modeling of storage in CAISO markets, it is unclear how CAISO expected the Vistra presentation to move forward resolution of issues being discussed in the Storage Design and Modeling initiative. CESA does note that Vistra highlighted the importance of CAISO meeting its commitment to CESA to provide documentation of the constraints enforced on storage resources dispatch and SOC calculation in the IFM, RUC, STUC, FMM, and RTD.

CESA agrees with the general notion raised that when the market enforces SOC management constraints that lead to uneconomic results, storage should be eligible for real-time uplift. As CESA noted in our comments on working group session 8, the CAISO implemented the ancillary services (AS) SOC constraint based on a policy decision to maintain AS awards "at any cost." We understood Vistra’s presentation to be to try to ask whether there should be an alternative to this policy decision to explore whether an alternative to provide more control to storage scheduling coordinators in exchange for eliminating uplift could be considered. As we put in our previous comments, since CAISO is making a policy decision to maintain AS at any cost it is appropriate to make storage whole for this choice. While CESA prefers maintaining uplift with the changes we have proposed, we do agree that if uplift is eliminated or significantly limited then revisiting the policy decision to maintain AS at any cost is needed and that the ability to reflect opportunity costs in energy bids must be ensured.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

See Cal Advocates response to Question 10.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E provides the following positions on Vistra’s questions:

Who should be responsible for managing the storage’s SOC – SC or ISO?

Batteries should manage their own SOC, provided CAISO has sufficient confidence —on an aggregate basis — in the deliverability of battery energy awarded in the markets or dispatched by CAISO.
The CAISO’s RA framework (distinct from the PUC’s related RA framework) could help secure energy guarantees on a planning basis, potentially through “slice of day” submission to indicate storage commitments by batteries.
Currently, day-ahead bid-in SOC is managed by SCs, while real-time SOC is managed primarily by CAISO over a myopic horizon. One option for longer-term real time planning would be constraining end-of-horizon or/and binding dispatches to ensure the feasibility of day-ahead awards, similar to energy-limited hydro.

Is allowing market enforcing physical parameters similar to the physical constraints of other assets (Pmin,Pmax)?
- Battery operators appear to want CAISO to manage assets subject to real physical constraints estimated based on telemetry, as evidenced by the time spent on the foldback issue. If this is not the case, as Vistra suggests, battery operators should weigh in to indicate this.
- If battery operators want CAISO to enforce SOC parameters, they must accept the current market model.
- Vistra’s assertion that batteries should have the option to manage their own SOCs independently should be addressed by CASIO with legal and tariff clarity.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV appreciates Vistra’s proposal and agrees with the importance of storage resources being able to self-manage their SOC. REV encourages CAISO to provide more time for group discussion in a workshop on the questions posted by Vistra, as they are important foundational positions for being able to move forward other issues including DEB and uplift as well as nonlinearity.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

Vistra’s proposal to allow self-management through unmitigated bidding, paired with non-performance penalties and the elimination of uplift payments, represents a significant departure from current design. This concept introduces complex questions around market power mitigation, risk allocation, and compliance. These issues would require careful analysis and discussion to understand and weigh the risks of any unintended consequences, such as impacts on reliability or inequitable cost shifts. Given the breadth of items in scope already, along with CAISO’s and stakeholder’s resource constraints, we recommend prioritizing other topics in the SDM initiative—such as uplift redesign, DEB redesign, and SOC accuracy measures—that can deliver immediate benefits to storage resources and scheduling coordinators.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra has been waiting for the CAISO to create a forum for higher level policy discussions that allow connecting dots on complex issues regarding SOC management and who should bear the costs associated with its mismanagement through either penalties on the Scheduling Coordinator or assessing uplift to load in this effort that has been on-going for almost a year. SOC management and uplift is inextricably linked, and we are losing confidence that this foundational fact is understood. We request the CAISO pause discussions on more robust, holistic improvements to SOC management until after EDAM/DAME has gone live. Since uplift & SOC management are inextricably linked, Vistra agrees that if CAISO pauses its pursuit of uplift changes until after EDAM/DAME it should also pause its discussions on SOC management.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF would like to take this opportunity to remind the CAISO and stakeholders that the original intent of this policy effort was to take a step back and discuss at a policy level first how we feel storage resources should be managed. This includes a discussion around what constraints are in the market, what tools SCs have to manage the resources on their end, and any other revenue and cost implications like BCR, no pay for ancillary services, etc. We believe Vistra’s presentation was trying to initiate those discussions and bring it back to a policy level first. While we appreciate the CAISO providing the information on what constraints and SOC formulations are in the market today (and planned for implementation), the discussions have continued to be in the weeds of those constraints and formulas and thus derailing the higher level policy conversation around how storage resources should be modeled and managed.

Thus WPTF strongly encourages the CAISO and stakeholders to engage in discussions at a policy level first that really try to identify the appropriate balance between market constraints and market participant tools as means to managing storage resources.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES appreciates Professor Chen's presentation as an excellent academic exercise that rigorously explores multi-interval dispatch pricing under uncertainty and the fundamental relationship between state-of-charge intertemporal constraints and bid cost recovery and lost opportunity cost issues. Professor Chen's theoretical work on Temporal Locational Marginal Pricing (TLMP) and its mathematical framework provides valuable insights into how pricing mechanisms can address storage's unique intertemporal operational challenges in ways that extend beyond conventional generator ramp constraints. AES recognizes the intellectual contribution of this research to advancing understanding of storage economics and market design principles in multi-interval dispatch environments.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

No comments.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates does not have comments at this time.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

No comment.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV defers comments on this issue at this time.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

No comment.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

We recommend that future stakeholder meetings prioritize content directly related to ongoing policy discussions, reserving academic presentations for separate sessions as appropriate. In the future, we expect CAISO to better manage content for a policy meeting and navigate items that are irrelevant to the policy effort to other venues.

Flexible Ramping Product’s forecasted movement was developed to address the need to price ramping and SOC into the binding clearing price. The issue raised has at least partially been addressed in the Flexible Ramping Product introduction to our market design. If there are concerns with FRP performance then these should be taken up in either EDAM Enhancements or Price Formation Enhancements.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

13. Provide your organization’s comments regarding the update provided regarding the high sustainable limit (to ease the development of comments, please note that a more detailed review of the proposed guidance is included in the materials presented September 29, 2025).

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES supports CAISO's efforts to enhance telemetry and resource information collection that will improve dispatch accuracy and operational visibility across all resource types. AES recognizes that clear guidance on how HSL proposals apply consistently across similar resource categories is essential to ensuring equitable treatment and operational clarity in CAISO's market design. AES also supports CAISO’s efforts to address these issues.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

In general, CESA supports reasonable requests by CAISO to enhance telemetry and other resource information that will improve the CAISO dispatch of resources. During this and previous working groups, CAISO mentioned that the iHSL proposal would apply to all solar resources.

CESA is appreciative that CAISO engaged the Large Solar Association (LSA) to ensure their participation in this initiative. However, CESA is unclear why this topic was presented again but without additional information on the request CAISO has of solar resources.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates does not have comments at this time.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

PG&E agrees with CAISO’s clarification on why it does not automatically generate (High Sustainable Limit) HSL values for resources. While CAISO recommends a calculation method, resources may choose alternative approaches, and CAISO cannot unilaterally calculate HSL because other factors beyond those in the recommended formula may influence the value.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV defers comments on this issue at this time.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

SDG&E appreciates the discussion on this topic and looks forward to further clarification regarding the iHSL calculation and methodology, as well as any requirements on its submission, in the upcoming SDM paper.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Following this discussion, Vistra continues to be uncertain of the problem driving the data integrity concerns. We encourage the CAISO to be crisper on the problem that they are trying to solve and whether it is a small enough issue that “guidance” is sufficient or if the underlying concern merits requiring consistent practice across VERs. Without making this a requirement it may be difficult to bridge some of the challenges that projects that are not fully owned and operated by the same entity may experience in determining whose obligation it is to ensure accuracy – Generator Owner or the Scheduling Coordinator – and whether all owners – e.g., Jointly Owned Units – must coordinate the methodologies across shares of the unit(s). This issue seems more complex given the different types of ownership structures that exist and we encourage more consideration of this as CAISO makes its problem statement crisper and assesses what type of solution best addresses any operational issues.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

14. Provide your organization’s comments regarding the update and materials on outage reporting for distribution-level resources. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4)

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

No comments

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA supports the CAISO’s proposed changes to this element.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA does not support using a nature of work that is not exempt from the resource adequacy availability incentive mechanism (RAAIM) for WDAT storage resources subject to distribution charging constraints. CESA supports including the charging restrictions placed on WDAT storage resources in the Master File. If these operational constraints were modeled in the optimization, there would be no exposure to RAAIM penalties. Until the operational constraints are modeled, WDAT storage resources should continue to use an outage nature of work that is exempt from RAAIM penalties.

First, it is illogical to subject storage resources to RAAIM penalties if the CAISO’s ultimate goal is to introduce new Master File parameters to adequately reflect distribution-level charging restrictions in the market optimization. The CAISO is unjustified in applying a RAAIM penalty for a near-term solution when – once the operational characteristic is included in the market model – there would be no outage subject to a RAAIM penalty.

Second, if the CAISO has issues with the calculation of QC developed by the CPUC, CAISO should engage in a CPUC process and not inappropriately apply RAAIM penalties the purpose of which is NOT to validate QC calculations.

CAISO attempted to justify its position by arguing that WDAT storage resources made this decision by not choosing Firm charging service. This was not a viable choice for resources interconnecting with SCE. SCE requires that resources fund all upgrades to resolve all N-1 contingencies, which is an unreasonable expectation of a project developer. In addition, the static charging tables are intended to be an interim solution put in place until SCE can deploy a sub-transmission level constraint management system (CMS). SCE currently estimates that this system will be completed in Q2 of 2027. CESA notes that the CAISO’s security constrained economic dispatch (SCED) enforces N-1 contingencies in the market and does not penalize storage resource not dispatched to charge because a constraint is binding. This further justifies using a RAAIM exempt nature of work during this interim period.

CESA opposes using the “ambient due to fuel insufficiency” nature of work. The CAISO proposal is discriminatory against distribution interconnected resources for the following reasons:

Grid-scale resources are commonly dispatched lower than their full capability to respect N-1 constraints in the security constrained economic dispatched and not penalized by RAAIM. Distribution interconnected storage resources respect N-1 limitations by following the charging restrictions established by the PTO.
The Off Grid Charging Indicator (OGCI) is a CAISO SIBR parameter that, when enabled, prevents grid-charging and ancillary service awards. This is used to prevent charging storage resources when co-located with solar. When the sun is not shining, the storage resource cannot be charged. Since this constraint (contractual limitation, not physical) is modeled in the market, there is no need for the storage resource to enter an outage. The storage resource is not subject to RAAIM even though it cannot charge in certain hours.

The appropriate solution for distribution charging restrictions is to model this resource’s charging constraint in the market. In the interim, outage cards should be used which are RAAIM exempt to communicate the charging limitation and ensure feasible dispatch instructions result from the market optimization.

CAISO should withdraw the BPM Proposed Revision Request (PRR) clarifying that distribution-level charging constraints fall under the ‘ambient due to fuel insufficiency’ nature of work. It was inappropriate for CAISO to move forward with a PRR given the limited discussion on the topic in the last working group. In fact, the PRR notification was made November 25 which is conveniently the day prior to the Storage Design and Modeling working group comments due date.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates does not have comments at this time.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

No comment.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV defers comments on this issue at this time.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

No comment.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra will respond following discussion in December.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF will hold comments until after the Dec 4 meeting.

15. Provide your organization’s comments regarding the materials and upcoming discussion on the co-located variable energy resource Follow DOT topic. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

AES looks forward to the December 4 discussion on co-located resources follow DOT procedures, as the current instruction creates operational constraints when ancillary services are awarded to co-located storage-VER facilities. AES recommends that CAISO evaluate allocating upward headroom below the aggregate capability ceiling on a pro rata basis, based on variable energy resource dispatch, as a reasonable approach to enabling more efficient storage dispatch while respecting facility-level transmission constraints.

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

CESA looks forward to having additional discussions on December 4th. The current follow DOT instruction is overly restrictive when ancillary services are awarded to co-located resources. Allocating upward headroom below the ACC pro rata by VER resource dispatch seems a reasonable starting point.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates does not have comments at this time.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

No comment.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV defers comments on this issue at this time.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

No comment.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra will respond following discussion in December.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF will hold comments until after the Dec 4 meeting.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

No comments

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

No comments.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates does not have comments at this time.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

No comment.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV defers comments on this issue at this time.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

No comment.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

Vistra will respond following discussion in December.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

WPTF will hold comments until after the Dec 4 meeting.

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES

Submitted 11/26/2025, 04:39 pm

Contact

Rahul Kalaskar (rahul.kalaskar@aes.com)

No comments

California Community Choice Association

Submitted 11/26/2025, 11:38 am

Contact

Shawn-Dai Linderman (shawndai@cal-cca.org)

CalCCA has no additional comments at this time.

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

Contact

Donald Tretheway (donald.tretheway@gdsassociates.com)

No additional comments.

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

Contact

Aprille Girardot (agirardot@caiso.com)

Please see the PDF attached below the final question for DMM's fully formatted complete set of comments. For the reader's convenience, the complete text of the comments is pasted in response to #1, but there may be some formatting errors.

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm

Contact

Paul Worhach (paul.worhach@cpuc.ca.gov)

Cal Advocates reiterates our previous position that CAISO should develop and apply market power mitigation to hybrid resources.[1]

[1] Cal Advocates July 2025 Comments, response to Question 8.

Middle River Power, LLC

Submitted 11/26/2025, 03:08 pm

Contact

Brian Theaker (btheaker@mrpgenco.com)

MRP has no comment on this topic.

NV Energy

Submitted 11/26/2025, 03:11 pm

Contact

Rodger Manzano (RodgerJoseph.Manzano@nvenergy.com)

No comment.

Pacific Gas & Electric

Submitted 11/25/2025, 01:49 pm

Contact

JK Wang (jvwj@pge.com)

No comment.

Portland General Electric

Submitted 11/26/2025, 09:49 am

Contact

Jonah Cabral (jonah.cabral@pgn.com)

Rev Renewables

Submitted 11/26/2025, 11:02 am

Contact

Renae Steichen (rsteichen@revrenewables.com)

REV has no further comments at this time.

San Diego Gas & Electric

Submitted 11/26/2025, 11:40 am

Contact

Nikki Emam (nemam@sdge.com)

No comment.

SCE

Submitted 11/26/2025, 01:29 pm

Contact

Jonathan Lawson Rumble (jonathan.rumble@sce.com)

SRP

Submitted 11/24/2025, 02:07 pm

Contact

Mark Shoemaker (mark.shoemaker@srpnet.com)

Vistra Corp.

Submitted 11/26/2025, 04:41 pm

Contact

Cathleen Colbert (cathleen.colbert@vistracorp.com)

We encourage CAISO to consider adjustments to the meeting format to better facilitate collaborative problem-solving among stakeholders.

WPTF

Submitted 12/02/2025, 09:55 am

Submitted on behalf of
Western Power Trading Forum

Contact

Kallie Wells (kwells@gridwell.com)

AES
California Community Choice Association
California Energy Storage Alliance (CESA)
California ISO - Department of Market Monitoring
California Public Utilities Commission - Public Advocates Office
Middle River Power, LLC
NV Energy
Pacific Gas & Electric
Portland General Electric
Rev Renewables
San Diego Gas & Electric
SCE
SRP
Vistra Corp.
WPTF

AES
Submitted on 11/26/2025, 04:39 pm

No attachments

California Community Choice Association
Submitted on 11/26/2025, 11:38 am

No attachments

California Energy Storage Alliance (CESA)
Submitted on 11/26/2025, 03:31 pm

No attachments

California ISO - Department of Market Monitoring
Submitted on 11/26/2025, 10:44 am

DMM Comments on Storage Design and Modeling November 12, 2025 Working Group Presentation - Nov 26, 2025.pdf

California Public Utilities Commission - Public Advocates Office
Submitted on 11/26/2025, 04:45 pm

No attachments

Middle River Power, LLC
Submitted on 11/26/2025, 03:08 pm

No attachments

NV Energy
Submitted on 11/26/2025, 03:11 pm

No attachments

Pacific Gas & Electric
Submitted on 11/25/2025, 01:49 pm

No attachments

Portland General Electric
Submitted on 11/26/2025, 09:49 am

No attachments

Rev Renewables
Submitted on 11/26/2025, 11:02 am

No attachments

San Diego Gas & Electric
Submitted on 11/26/2025, 11:40 am

No attachments

SCE
Submitted on 11/26/2025, 01:29 pm

SCE_Comments_Nov 26.docx

SRP
Submitted on 11/24/2025, 02:07 pm

Storage Design and Modeling 11.26.2025 SRP Comments.docx

Vistra Corp.
Submitted on 11/26/2025, 04:41 pm

No attachments

WPTF
Submitted on 12/02/2025, 09:55 am

No attachments

Stakeholder center

Comments on Nov 12 Hybrid Meeting, Working Group Session 10: Uplift and Default Energy Bids (DEB), State-of-Charge Management, and Mixed-Fuel and Distribution-Level Resources

Storage design and modeling

AES Submitted 11/26/2025, 04:39 pm

1. Please provide a summary of your organization's general comments on the materials shared and subsequent discussion during the Nov 12 meeting.

2. Provide your organization’s comments regarding the initiative’s overview and schedule.

3. Provide your organization’s comments regarding the update on nonlinearity.

4. Provide your organization’s comments regarding the presentation offered by REV Renewables.

5. Provide your organization’s comments regarding the guiding principles related to the Uplift & Default Energy Bid (DEB) topic group.

6. Provide your organization’s comments regarding the responses on Day-Ahead Uplift and Initial State-of-Charge (SOC) as part of the Uplift & Default Energy Bid (DEB) topic group.

7. Provide your organization’s comments regarding Real-Time Uplift and Proposed Approaches as part of the Uplift & Default Energy Bid (DEB) topic group.

8. Provide your organization’s comments regarding the notion of establishing a form of System SOC target or constraint, including your perspective on how the SOC target should be established and the relationship this target or constraint would have with market products.

9. Provide your organization’s comments regarding the potential modifications to the storage DEB to enable the representation of real-time conditions and ease its use across different geographies.

10. Provide your organization’s comments regarding the presentation offered by Pacific Gas & Electric (PG&E).

11. Provide your organization’s comments regarding the presentation offered by Vistra, including the discussion questions included in their materials.

12. Provide your organization’s comments regarding the presentation offered by Cong Chen Ph.D., Assistant Professor, Thayer School of Engineering, Dartmouth College.

13. Provide your organization’s comments regarding the update provided regarding the high sustainable limit (to ease the development of comments, please note that a more detailed review of the proposed guidance is included in the materials presented September 29, 2025).

https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Sep-29-2025.pdf

14. Provide your organization’s comments regarding the update and materials on outage reporting for distribution-level resources. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4)

15. Provide your organization’s comments regarding the materials and upcoming discussion on the co-located variable energy resource Follow DOT topic. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

16. Provide your organization’s comments regarding the upcoming discussion on mixed-fuel ancillary services. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

17. Please provide any additional comments, feedback, or examples in the Nov 12 stakeholder meeting. You may upload examples or data using the Attachments field below.

California Community Choice Association Submitted 11/26/2025, 11:38 am

1. Please provide a summary of your organization's general comments on the materials shared and subsequent discussion during the Nov 12 meeting.

2. Provide your organization’s comments regarding the initiative’s overview and schedule.

3. Provide your organization’s comments regarding the update on nonlinearity.

4. Provide your organization’s comments regarding the presentation offered by REV Renewables.

5. Provide your organization’s comments regarding the guiding principles related to the Uplift & Default Energy Bid (DEB) topic group.

6. Provide your organization’s comments regarding the responses on Day-Ahead Uplift and Initial State-of-Charge (SOC) as part of the Uplift & Default Energy Bid (DEB) topic group.

7. Provide your organization’s comments regarding Real-Time Uplift and Proposed Approaches as part of the Uplift & Default Energy Bid (DEB) topic group.

8. Provide your organization’s comments regarding the notion of establishing a form of System SOC target or constraint, including your perspective on how the SOC target should be established and the relationship this target or constraint would have with market products.

9. Provide your organization’s comments regarding the potential modifications to the storage DEB to enable the representation of real-time conditions and ease its use across different geographies.

10. Provide your organization’s comments regarding the presentation offered by Pacific Gas & Electric (PG&E).

11. Provide your organization’s comments regarding the presentation offered by Vistra, including the discussion questions included in their materials.

12. Provide your organization’s comments regarding the presentation offered by Cong Chen Ph.D., Assistant Professor, Thayer School of Engineering, Dartmouth College.

13. Provide your organization’s comments regarding the update provided regarding the high sustainable limit (to ease the development of comments, please note that a more detailed review of the proposed guidance is included in the materials presented September 29, 2025).

https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Sep-29-2025.pdf

14. Provide your organization’s comments regarding the update and materials on outage reporting for distribution-level resources. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4)

15. Provide your organization’s comments regarding the materials and upcoming discussion on the co-located variable energy resource Follow DOT topic. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

16. Provide your organization’s comments regarding the upcoming discussion on mixed-fuel ancillary services. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

17. Please provide any additional comments, feedback, or examples in the Nov 12 stakeholder meeting. You may upload examples or data using the Attachments field below.

California Energy Storage Alliance (CESA) Submitted 11/26/2025, 03:31 pm

1. Please provide a summary of your organization's general comments on the materials shared and subsequent discussion during the Nov 12 meeting.

2. Provide your organization’s comments regarding the initiative’s overview and schedule.

3. Provide your organization’s comments regarding the update on nonlinearity.

4. Provide your organization’s comments regarding the presentation offered by REV Renewables.

5. Provide your organization’s comments regarding the guiding principles related to the Uplift & Default Energy Bid (DEB) topic group.

6. Provide your organization’s comments regarding the responses on Day-Ahead Uplift and Initial State-of-Charge (SOC) as part of the Uplift & Default Energy Bid (DEB) topic group.

7. Provide your organization’s comments regarding Real-Time Uplift and Proposed Approaches as part of the Uplift & Default Energy Bid (DEB) topic group.

8. Provide your organization’s comments regarding the notion of establishing a form of System SOC target or constraint, including your perspective on how the SOC target should be established and the relationship this target or constraint would have with market products.

9. Provide your organization’s comments regarding the potential modifications to the storage DEB to enable the representation of real-time conditions and ease its use across different geographies.

10. Provide your organization’s comments regarding the presentation offered by Pacific Gas & Electric (PG&E).

11. Provide your organization’s comments regarding the presentation offered by Vistra, including the discussion questions included in their materials.

12. Provide your organization’s comments regarding the presentation offered by Cong Chen Ph.D., Assistant Professor, Thayer School of Engineering, Dartmouth College.

13. Provide your organization’s comments regarding the update provided regarding the high sustainable limit (to ease the development of comments, please note that a more detailed review of the proposed guidance is included in the materials presented September 29, 2025).

https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Sep-29-2025.pdf

14. Provide your organization’s comments regarding the update and materials on outage reporting for distribution-level resources. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4)

15. Provide your organization’s comments regarding the materials and upcoming discussion on the co-located variable energy resource Follow DOT topic. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

16. Provide your organization’s comments regarding the upcoming discussion on mixed-fuel ancillary services. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

17. Please provide any additional comments, feedback, or examples in the Nov 12 stakeholder meeting. You may upload examples or data using the Attachments field below.

California ISO - Department of Market Monitoring Submitted 11/26/2025, 10:44 am

1. Please provide a summary of your organization's general comments on the materials shared and subsequent discussion during the Nov 12 meeting.

2. Provide your organization’s comments regarding the initiative’s overview and schedule.

3. Provide your organization’s comments regarding the update on nonlinearity.

4. Provide your organization’s comments regarding the presentation offered by REV Renewables.

5. Provide your organization’s comments regarding the guiding principles related to the Uplift & Default Energy Bid (DEB) topic group.

6. Provide your organization’s comments regarding the responses on Day-Ahead Uplift and Initial State-of-Charge (SOC) as part of the Uplift & Default Energy Bid (DEB) topic group.

7. Provide your organization’s comments regarding Real-Time Uplift and Proposed Approaches as part of the Uplift & Default Energy Bid (DEB) topic group.

8. Provide your organization’s comments regarding the notion of establishing a form of System SOC target or constraint, including your perspective on how the SOC target should be established and the relationship this target or constraint would have with market products.

9. Provide your organization’s comments regarding the potential modifications to the storage DEB to enable the representation of real-time conditions and ease its use across different geographies.

10. Provide your organization’s comments regarding the presentation offered by Pacific Gas & Electric (PG&E).

11. Provide your organization’s comments regarding the presentation offered by Vistra, including the discussion questions included in their materials.

12. Provide your organization’s comments regarding the presentation offered by Cong Chen Ph.D., Assistant Professor, Thayer School of Engineering, Dartmouth College.

13. Provide your organization’s comments regarding the update provided regarding the high sustainable limit (to ease the development of comments, please note that a more detailed review of the proposed guidance is included in the materials presented September 29, 2025).

https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Storage-Design-and-Modeling-Sep-29-2025.pdf

14. Provide your organization’s comments regarding the update and materials on outage reporting for distribution-level resources. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4)

15. Provide your organization’s comments regarding the materials and upcoming discussion on the co-located variable energy resource Follow DOT topic. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

16. Provide your organization’s comments regarding the upcoming discussion on mixed-fuel ancillary services. This topic will be discussed during the next stakeholder meeting (scheduled for Dec. 4).

17. Please provide any additional comments, feedback, or examples in the Nov 12 stakeholder meeting. You may upload examples or data using the Attachments field below.

Attachments

AES

Submitted 11/26/2025, 04:39 pm

California Community Choice Association

Submitted 11/26/2025, 11:38 am

California Energy Storage Alliance (CESA)

Submitted 11/26/2025, 03:31 pm

California ISO - Department of Market Monitoring

Submitted 11/26/2025, 10:44 am

California Public Utilities Commission - Public Advocates Office

Submitted 11/26/2025, 04:45 pm