Comments on EDAM Implementation - 11/14 Q&A

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

Brookfield Renewable Trading and Marketing LP (BRTM) and Brookfield Renewable Energy Marketing US LLC (BREMUS), collectively, Brookfield Renewable, appreciate the opportunity to submit these comments on the CAISO’s November EDAM workshops on intertie pricing and import resource adequacy (RA) scheduling. Brookfield Renewable has submitted confidential information and questions through the CAISO's customer inquiry, dispute and information (CIDI) system.

Overall, Brookfield Renewable supports, as discussed at the November 14, 2025, workshop, that the CAISO retain, through 2026 (transition period), the existing SP-Tie modeling for intertie scheduling/pricing at CAISO interties with non-EDAM balancing areas and the existing rules for scheduling import RA. In addition, Brookfield Renewable supports the CAISO’s plan to defer submitting the proposed tariff clarification filing until early 2026 and to hold additional stakeholder meetings to help refine and clarify implementation details in support of a May 1, 2026, EDAM implementation.

As discussed at the November workshops, Brookfield Renewable urges the CAISO, in future discussions of the above topics, to clearly distinguish between the roles and functional responsibilities of market participants, the CAISO as market operator, EDAM entities, and EIM entities when submitting and processing bids/schedules at either CAISO intertie points, EDAM transfer locations, or effecting EIM transfers.  Finally, and as also noted at the workshops, Brookfield Renewable asks that the CAISO carefully assess the impact of any proposed changes on existing commercial trading practices, including power sales/purchases made under the existing Western System Power Pool (WSPP) agreements.

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

Intertie Scheduling

1. Will Transaction ID's be available for an SC within CAISO for import/export transactions with the implementation of EDAM (for both EDAM and non-EDAM entities)?

Resource Adequacy (RA) treatment questions: 

1. CDWR requests for examples illustrating how RA imports from a non-resource specific resource from, a) an adjacent WEIM participant BAA (non-EDAM participant), b) adjacent EDAM BAA will be subject to RA must offer obligation in the EDAM and RTM.  
2. The CAISO document indicates that the Resource Adequacy Availability Incentive Mechanism (RAAIM) applies to the intertie resources used before the RA obligation reassignment, and to the EDAM/EIM physical resources after the reassignment. Will there be a separate RAAIM assessment for resource prior to reassignment and the other resource after the reassignment? 
3. In 5.1.3 the document indicates the SC for the SR at the EIM BAA DGAP must be the same as the SC for the SR at the GGAP. Can one entity become the SC for both (receiving SC for both SR at GGAP and the EIM BAA DGAP)? 
4. Who registers the System Resource (SR)? Is it a new requirement to register in the CAISO Masterfile? 

CRR Implementation question: 

5. CDWR requests for an example showing how existing CRR from the 2026 annual Allocation processes and Long-Term (LT) Allocation processes sourced at Scheduling Points (Interties) will be settled in the interim period.   
6. Furthermore, CDWR would like to know in which CRR Allocation processes (for example: July 2026 monthly CRR Allocation process; 2027 annual CRR Allocation process, etc), Market Participants would be allowed to request CRR from sources located in the adjacent to CAISO Balancing Authorities. 

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

Please see attached comments.

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

Can you please explain the sourcing requirements for a Transfer from (1) the CAISO to an adjacent (for simplicity) EDAM entity (e.g., NVE) and (2) between two non-CAISO EDAM entities.  By sourcing requirements, I mean what obligations must the source of the Transfer meet?  Must it be a specific resource or will the EDAM pool fill the transfer?  Must it show a bid in the market (a MOO)? Must it demonstrate that it is not committed to another LRA?  Must it receive a RUC schedule in order for the Transfer to be valid and have a priority equivalent to native load? 

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

Idaho Power is appreciative of the detailed workshops on November 5-6, which shared a significant amount of complex information and examples.

CAISO must allow sufficient time for participants to ask questions and provide comments and feedback.  That did not occur in these workshops. We appreciate the opportunity to submit comments here and the Q&A follow-up meeting that has been scheduled for November 14^th.

PacifiCorp’s and CAISO’s implementation of EDAM has significant impacts on adjacent BAs and market participants. We understand that PacifiCorp and CAISO each have their own specific and unique requirements, but we are being told inconsistent things by the two entities about what will be required.  CAISO and PacifiCorp should work together to try to align their explanations in these types of meetings to provide market participants the full story.  For example, in the Nov. 4th workshop, we specifically asked if we would need a CRN to use long-term transmission rights we hold on PacifiCorp's system, and CAISO told us “no”.  This is contrary to what PacifiCorp has told us.  We believe we now understand how the answers work together, and that we will use a CRN per PacifiCorp's processes, but having the two entities tell us different things each time we ask is very confusing and creates delays.

In addition, CAISO should consider clearly defining terms and avoiding redundant or duplicated terminology or acronyms. For example, CAISO used the acronym "IR" in these workshops to mean "Intertie Resource"; however, up to now, the acronym "IR" has meant "Imbalance Reserves" in the EDAM context. Is CAISO planning to use IR to mean both terms in the future?  If so, that will very confusing.  In addition, we were previously told by Pacificorp that interties between EDAM BAAs and WEIM BAAs would be called “System Resources (SR).” However, in the November 5^th EDAM Implementation Workshop presentation, CAISO used the term “IR” to represent those intertie resources. CAISO did mention on slide 8 that ‘IR’ is used as shorthand for SR, IT, or TG but this creates further confusion on the terminology that should be used to represent the intertie resources between EDAM BAAs and those that are not in EDAM.    Also, it appears that "TSR" is being used interchangeably between EDAM and WEIM, but it has very different meanings in each context: Transfer System Resource (TSR) in EDAM, and Energy Transfer System Resource (ETSR) in WEIM.  Using the same acronyms to mean different things is very confusing and not helpful.

We are unclear if these comments should be submitted in the comment template for the November 5th meeting, or for the November 14th meeting, so we are submitting them in both out of an abundance of caution. Thank you.

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

PacifiCorp thanks the CAISO for the additional stakeholder call to answer outstanding questions from the initial November 5th and 6th Intertie Scheduling workshops and the presentation on the EDAM transitional period plan during the November 14th stakeholder call. During the initial calls, the CAISO presented on the EDAM design transition from the Scheduling Point (SP)-Tie to a Generation Aggregation Point (GAP)-Tie construct for day-ahead market bids and the congestion revenue rights auction, mechanisms for transfers between EDAM and WEIM participants in real-time, and how replacement schedules for Generic GAP (GGAP) would work. PacifiCorp’s comments provide feedback on the GAP-Tie design and its support for the November 14th EDAM transitional period plan.  

Prior to the EDAM transitional period plan, non-resource specific generation would be bid into the day-ahead market either under a Default GAP (DGAP), if the source BAA was known, or a GGAP if the source Balancing Authority Area (BAA) was not known in addition to a Custom GAP (CGAP) for resource specific generation. Bidding at various GAP-Ties would create multiple prices, where there was only one price before at the SP-Tie. This change will require market participants to modify their business practices prior to implementation, which doesn’t lend much time prior to go-live. PacifiCorp, among other entities in the West, often transact with counterparties that bid at the CAISO interties to hedge positions and believe the GAP-Tie concept requires thorough evaluation from stakeholders to assess the pricing impacts that could result in the bilateral market due to the multiple prices from the GAP-Tie concept.   

Specifically, the CAISO confirmed that schedules at the GGAP would be required to be bought back and resubmitted at a valid DGAP settlement location. If not, then Scheduling Infrastructure Business Rules (SIBR) would zero out the schedule in real-time due to the GGAP not being a valid settlement location creating a new process that market participants will need to adapt to. This step could introduce financial impacts that market participants will need to manage. Notwithstanding, the new GAP-Tie construct would ultimately expose the day-ahead schedule to real-time costs resulting from the marginal loss and marginal congestion between the intertie and the generating resource at the source BAA which adds additional risk to hedging positions. PacifiCorp understands this concept was created to accommodate bilateral transactions where market participants may not know the generator source BAA prior to the day-ahead market closure at 10am.  

The CAISO has since walked back the GGAP and CGAP design for the all EDAM interties and opted to retain the current SP-Tie construct at CAISO interties, while having a single DGAP-Tie price at PacifiCorp’s interties. 

• PacifiCorp supports the retention of status quo until additional stakeholder discussions can take place so that entities understand the financial implications of moving to a GAP-Tie construct.

• PacifiCorp supports the CAISO improving their power flow and congestion modeling and understands the single SP-Tie does not provide the CAISO enough information for where energy is flowing on the system. 

• PacifiCorp supports having a single DGAP-Tie price at PacifiCorp’s interties.

However, as EDAM is a novel design, it is prudent to take a step back and assess the downstream implications before implementation of a GAP-Tie design for day-ahead market participation at the scheduling coordinator level. PacifiCorp encourages the CAISO to attain operational data for how the market is functioning under the current design for intertie scheduling where stakeholders can then assess the need, if at all, for the GAP-Tie design. 

In addition, PacifiCorp would like to better understand how a single DGAP-Tie pricing would work in the case when there are multiple BAAs adjacent to PacifiCorp at an intertie location, such as Four Corners or MIDC. For example, during the November 14th workshop, it was mentioned that PacifiCorp East’s Four Corners intertie would be held to the AZPS DGAP.   

PacifiCorp appreciates the CAISO's willingness to work with stakeholders on the design and looks forward to additional discussions. 

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

Thank you, CAISO, for hosting the EDAM Implementation Q&A workshop on November 14. To enable effective participation by market participants, we respectfully request the following clarifications and data:

• Interim EDAM FNM Availability
  During the November EDAM workshops, SCE requested an interim EDAM FNM—consisting of a power-flow snapshot (PSS/E RAW file) and general data—for market simulation. We recognize that CAISO’s original plan was to publish the EDAM FNM during the parallel market run and appreciate your willingness to consider an earlier release.
  Request: Could CAISO provide the EDAM FNM at its earliest convenience?
• Scheduling Points (SPs), ITCs, and DGAPs During the EDAM Transition Period
  While most CAISO BAA SP–ties will remain unchanged during the transition preiod, CRAGVIEW_1_GN001 and MONA_3_N501 will become internal to EDAM.
  Questions:
  • How will these two SPs be modeled in EDAM?
  • Will their associated ITCs continue to be enforced?
  • Will DGAPs be defined for the new EDAM BAAs—PACE and PACW—and if so, what are those definitions?
  • Based on current information, DGAP_LADWP-APND at tie point MPAC is expected to be available for intertie scheduling with PACE. Could CAISO confirm and provide the relevant details?

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

Shell Energy appreciates the opportunity to provide comments on the EDAM intertie workshops and commends CAISO for its hard work and significant progress on this complex technical topic. We especially value the publication of a rigorous, well-structured paper detailing the mechanics of the future intertie bidding framework in response to stakeholder feedback. The document and supporting workshops effectively clarified GAP types, explained the linkage between capacity awards and real-time dispatchability, and thoughtfully addressed conflicts between HASP intertie schedules and economic schedules.

While the workshops were highly informative, we remain concerned about a potential misalignment between stakeholder readiness and the proposed implementation timeline. The changes are inherently complex, and questions raised during the November 5–6 sessions suggest that many foundational concepts such as when to use DGAP versus GGAP, when intertie energy can be economically bid versus self-scheduled, or whether GGAP schedules qualify as physical supply for RA are not yet well understood across the stakeholder community.

Shell Energy has a few specific concerns:

• The GGAP is well defined in theory however, it appears to be operationally complex. Further, the treatment of an unreplaced GGAP schedule as a ‘virtual-like’ position is critical risk information that merits focused attention. While the intention of the GGAP is to solve the unknown source problem, it winds up creating a highly path dependent, multi-step tagging and replacement process with various bridging options. Additionally, the DA GGAP price vs. RT replacement and imbalance exposure is potentially difficult to model and hedge. This exposes participants to unknown imbalance costs, price uncertainty and potentially undermines confidence in RA imports.
• Many existing intertie arrangements today rely on non-EIM transmission and straightforward e-tagging. Entities currently schedule bilateral wheels through EIM BAAs today using PTP transmission and e-tags, but the future state will necessitate navigating a multi-layered framework of TSR/ETSR/MSR constructs whose financial value is mostly handled through BAA neutrality and transfer revenue distribution. This represents a significant increase in complexity when compared to the traditional bilateral + tagging methods and stakeholders will need time to assess commercial contracts, hedge risk and better understand how this is operationalized.
• The proposed import intertie RA framework is even more complex, as it operates on top of the intertie framework itself, necessitating various reassignments and navigation of multiple modeled layers (GGAP > DGAP > TSR > specific units) on tight DA and RT timelines with CIRA touchpoints and SC coordination. Additionally, RAAIM applies at several points thereby increasing financial risk.
• Shell Energy does not have a clear understanding of the extent to which the GAP-tie framework will impact intertie prices and risk exposure. Further, we are concerned that there is insufficient time to assess the impact of these changes under the proposed go-live date.

Given the apparent misalignment between stakeholder readiness and the proposed implementation timeline, Shell Energy recommends that CAISO consider delaying the intertie bidding framework, either in full or in part, until after EDAM go-live. If complete decoupling is not feasible, a phased approach may be considered, with direct interties and CGAP/DGAP introduced first, followed by more indirect and GGAP functionality, and finally full RA import integration.

To support stakeholder preparedness, we encourage the CAISO to develop supplemental materials. For example, a migration guide with before-and-after examples of tagging and registration processes would be valuable. This could clarify which arrangements must convert to ETSRs and what changes are required in tagging, contract language, and other upstream processes. 

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

Six Cities’ Comments:  The Six Cities generally support the CAISO’s proposals to retain SP-Tie modeling for intertie scheduling at CAISO interties with non-EDAM balancing authority areas (“BAAs”) for a transition period and SP-Tie modeling and settlement of Congestion Revenue Rights (“CRRs”) on CAISO’s system for the 2026 allocation and auction, as summarized at Slide 11 of the presentation for the 11/14/25 Q&A session on EDAM implementation.  However, the Six Cities remain extremely unclear as to what specific changes in procedures for scheduling imports and exports of resources, including Resource Adequacy imports, they, as load serving entities within the CAISO BAA, will need to make as of EDAM implementation, particularly with respect to scheduling procedures for ties with EDAM Entity BAAs.  Much of the discussion during the Q&A sessions to date has focused on scheduling procedures applicable to participants in EIM or EDAM Entity BAAs or in external BAAs.  The Six Cities request additional guidance and training focused on changes in scheduling procedures as a result of EDAM implementation that will apply to market participants located within the CAISO BAA. 

With respect to transparency and consistency of CAISO guidance regarding questions relating to EDAM implementation, the Six Cities request confirmation that the CAISO plans to post its responses to all stakeholder questions on EDAM implementation in a public location available to all interested entities.

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

The Sacramento Municipal Utility District (SMUD) appreciates the opportunity to submit comments regarding the EDAM Implementation meetings convened in November 2025. SMUD is an active participant in the California Independent System Operator’s (CAISO) day-ahead and real-time markets via the interties and currently operates within the Western Energy Imbalance Market (EIM) through the Balancing Authority of Northern California. Additionally, SMUD plans to join the Extended Day Ahead Market (EDAM) in 2027.

SMUD acknowledges CAISO’s responsiveness to stakeholder concerns initially raised during the August 2025 meeting and commends the ongoing engagement demonstrated by the additional meetings held in November. SMUD further appreciates CAISO’s decision to defer implementation of the Generation Aggregation Point (GAP)-Tie approach for modeling intertie transactions within the CAISO footprint until 2026 to allow for further stakeholder input. SMUD supports the proposed stakeholder initiative to evaluate and guide the transition to the GAP-Tie approach and looks forward to actively participating in this process.

SMUD respectfully submits the following inquiries:

Financial Treatment Under EDAM:

Stakeholders have voiced apprehension that changes in market design could alter how various resources are settled financially. Accordingly, SMUD seeks clarity on whether Tie Gen resources will experience any change in their financial settlement process under EDAM when it launches in Spring 2026. Currently, Tie Gen resources settle at the nodal price; will this remain unchanged, or are there circumstances under EDAM—such as implementation of gap pricing or other proposed settlement changes—where this may be modified? If there will be changes, SMUD requests detailed information on how these settlements will be calculated and what specific triggers would result in different financial outcomes for Tie Gen resources.

Impact of Gap Pricing:

Several stakeholders have raised concerns regarding transparency, complexity, and potential market distortions associated with gap pricing. SMUD echoes these concerns and specifically asks:

How will gap pricing affect settlement calculations and compensation for Tie Gen resources, especially for those that are utilized as Supporting Resources for non-resource-adequacy (non-RA)?

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

SCE appreciates CAISO listening to stakeholders and being willing to modify the implementation details based on the comments and reactions from stakeholders. However, SCE, seemingly like most stakeholders, is not clear how the new implementation details will actually function. The previous version of implementation details was accompanied by a working paper with detailed examples and very specific descriptions of how various resources would need to be treated through the EDAM day-ahead and EIM real-time markets. That working paper seems to have been removed from the CAISO’s website, but there has been no replacement published. Further, the tariff clarifications that seemed to cover these situations have not yet been updated. SCE has numerous questions about how to treat non-resource specific resource adequacy (RA) imports. Stakeholders would benefit greatly from further discussions with detailed examples stepping through the process. The CAISO should also explain how these scenarios will be tested through market sim and/or parallel operations to allow stakeholders to ensure that they have all systems and understandings ready to follow the process.

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

The Energy Authority (TEA) offers the attached revised comments/slides that build on its prior submitted written comments but pivot to focus on specific EDAM Intertie Scheduling scenarios and remaining concerns that recognize CAISO's decision to mostly maintain its existing SP-Tie functionality at a minimum for 2026 EDAM/DAME implementation and for the 2026 CRR cycle.

As noted in prior comments, TEA appreciates and acknowledges all the work of CAISO leadership and staff, as well as the effort put in by fellow stakeholders and CAISO's DMM, over the past week that has delivered a viable and supported solution that keeps EDAM implementation on track for May 1, 2026. TEA looks forward to continuing working with CAISO and other stakeholders down the road to revisit and/or build on CAISO's GAP-Tie work to ultimately develop efficient intertie and EDAM transfer solutions for future enhancement of the EDAM model. 

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

The Energy Authority (TEA) offers the following summary comments and observations regarding CAISO’s EDAM Intertie Scheduling implementation plans shared on August 21 and November 5-6. TEA expects to submit additional detailed comments and questions following the November 12 and 14 meetings and potentially amend aspects of its comments as more information is shared in those meetings and there is more time to assess the impacts of CAISO’s planned implementation components.

Summary Comments

Despite good intentions, the implementation decisions CAISO has been signaling since late August 2025 regarding intertie scheduling and CRR management under its “GAP-Tie” design have already begun destabilizing the EDAM go-live effort and disrupting critical Western forward financial and physical power, transmission, and RA markets. Continuing on the current GAP-Tie focused implementation path, with all the associated changes to CRR and Import RA functionality, in fact risks undermining much of the expected efficiency and reliability gains driving the combined EDAM and DAME efforts. These are not small changes and in no way would Western markets experience “business as usual” if they are implemented. Given the broader market environment in which the GAP-Tie functionality would live, it is unlikely it will achieve the goals CAISO outlined. Rather, it would likely just trade one set of modeling inaccuracies for another as entities become forced into attempting to work around the model to contain the price risk it introduces. Moreover, Western market participants, the EDAM Entities, and WEIM BAs and TSPs, as well as the CAISO itself, are unprepared for these elective and untested changes, and there is not time for them to "catch up" in the seven short months leading to go-live. CAISO therefore should set aside the proposed GAP-Tie functionality definitively and communicate to the market that it and the associated changes will not be a part of the EDAM or CRR markets at least through 2027. Doing so as quickly as possible will allow the 2026 Annual CRR Auction to proceed without further delay. It will also allow attention to be refocused on resolving intertie scheduling and pricing seams and other EDAM and DAME functionality issues stakeholders have already identified through MarketSim to support successful EDAM go-live on May 1, 2026.

Acknowledging Staff and Stakeholder Engagement

The significant effort of CAISO staff and leadership on this project, including George Angeledis, James Lynn, and Khaled Abdul-Rahman, among many others, is commendable. EDAM is an entirely new and untested market concept and DAME is introducing entirely new market products and constraints. Developing solutions for interconnected systems and processes given the resource and other constraints the May 1, 2026, go-live timeline demands is difficult enough on its own. Asking CAISO staff to do all of that without triggering seams issues with CAISO’s existing CRR, intertie, and RA markets, as well as the adjacent bilateral markets its LSEs rely on for critical supply and demand, all while troubleshooting onboarding issues in the non-CAISO EDAM areas, moves the bar even higher. CAISO staff have been stepping up to the challenge across the board. Even though course-correction is needed here, the effort that went into the plan is not wasted. The engagement it has driven among the broader CAISO stakeholder community around EDAM and DAME implementation progress and go-live expectations is a solid payoff for the effort invested and will help smooth the process from here. Likewise, CAISO’s pivoting to provide this immediate opportunity for comments and its organizing of additional meetings this week is exactly what was needed to keep that engagement high moving forward.

Assessing Proposed GAP-Tie Functionality

CAISO’s rationale for its proposed movement to a GAP-Tie or “resource specific” bidding structure is well-reasoned and well-intentioned, and not a surprise – it is a goal the CAISO has been pursuing since 2013 when it shelved its Full Network Model Phase 2 initiative following extensive stakeholder and MSC pushback. Experience in Eastern organized markets supports CAISO’s premise that moving to a resource-specific bidding framework in the DA market would improve the accuracy of models and overall improve the efficiency of markets, particularly as a foundation on which to build market-to-market seams enhancements. Carrying the concept through into the CRR market is a logical piece of that puzzle as well.

That said, it is no more appropriate and no less risky to attempt to shoehorn this functionality today into a market landscape that remains grounded in contract-path, bilateral-forward contracting than it was a dozen years ago. All the issues raised back then are still with us – the individual BAs and TSPs, the ownership alignment and contracting between generation and load outside the CAISO BAA, and the disconnect between the hedging available through CAISO’s CRR market and the physical-rights based hedging achieved in the rest of the West. Beyond that, there is not sufficient time to test the assumptions embedded in the proposed functionality, nor is there time to adapt EDAM Entity and others’ tariffs and business practices to deal with the carry-on effect of the changes. Moreover, adequate consideration has not been given to the unintended consequences and ripple effects these changes would have into other markets that themselves have orders of magnitude more value transacting in them than even the DA market. Combined, these points only further drive home that this is not functionality that should be pursued as part of the combined EDAM and DAME go-live for May 1, 2026, or left as a potential near-term change that could impact 2027 markets without advanced notice.

Instead, the GAP-Tie functionality should be considered going forward as a long-term target, likely after developing durable congestion revenue allocation solutions for the growing EDAM footprint. The GAP-Tie functionality work should have a timeline that recognizes the need for EDAM to mature and reach scale before solutions that rely on the absence of internal market seams can be approached.

Departure from EDAM Final Proposal, Consequences for EDAM Go-Live

While it is arguable whether CAISO has or could attain tariff authority to enact the GAP-Tie functionality, there is no question that its plans are a departure from both the EDAM model it developed with stakeholders in 2021-23 and the description of how the EDAM would work embedded in the PacifiCorp and Portland General EDAM Entity Tariffs recently approved by FERC. There also is no question whether CAISO’s EDAM Intertie scheduling vision would disrupt EDAM Entity onboarding efforts, causing them to initiate new Tariff and BP revision processes while deep into the MarketSim phase, upend WEIM Entity expectations and agreements, encourage early exit from the WEIM by entities committed to Markets+, and generally inject chaos into CAISO’s CRR and Import RA markets.

Opportunity Cost of Pursuing GAP-Tie Functionality

EDAM Entity and SC onboarding efforts since June 2025, combined with ongoing assessments of the transactional, price formation, hedging, and other seams EDAM creates with CAISO’s existing markets and forward financial and physical generation and transmission markets, have uncovered multiple teething issues that have not been adequately addressed in EDAM and DAME go-live planning to date. Pursuing the GAP-Tie functionality leaves less staff and stakeholder time to address these issues, which include:

• Intra-change transaction barriers that overly complicate EDAM LSEs’ ability to contract with on-system counterparties for RSE-eligible supply prior to the RSE-showing deadline;
• Ongoing uncertainty regarding day-one EDAM transfer paths;
• Lack of clarity regarding interchange pricing and congestion exposure under more complex transaction scenarios;
• Inability for entities to acquire Firm transmission to meet market requirements and be given the opportunity to hedge congestion risk; and
• Inability for NT customers to use the full quantity of rights they are billed for to receive a congestion hedge.

These and other issues fall somewhere between implementation concerns and policy concerns and may be drivers for Tariff clarifications at either/both the CAISO and/or EDAM Entity level. They should be scoped by stakeholders, discussed openly, and dealt with as soon as possible to promote a stable and successful EDAM go-live on May 1, 2026.

Distraction from EDAM’s and DAME’s Core Objectives

The primary goal of EDAM is to execute hourly unit commitment on a day-ahead basis informed by a centralized, automated view of available generation and transmission alongside wide-area forecasted demand and VERs to enhance the ability for the existing WEIM to find an optimal real-time solution without having to unwind an inefficient day-ahead plan. The primary goal of DAME is to adjust or add market components that support the EDAM concept and enhance its efficiency and reliability. At a high level, these are the game plans for EDAM and DAME the Board and GB signed off on. Neither body approved nor intended for EDAM or DAME to overhaul CAISO’s non-EDAM intertie markets or add undue complication to them, or to make unnecessary changes to or otherwise disrupt its CRR or RA markets. In fact, both cautioned that the CAISO should keep the scope of EDAM and DAME tight and prevent “perfect from being the enemy of good” to avoid delaying achieving a stable implementation as soon as possible. CAISO should be focused on doing everything it can to ensure the core objectives of EDAM and DAME are met, including promoting the continuance of the liquid bilateral power markets that exist at its and the external EDAM Entities’ borders.

CAISO Should Maintain Its Existing Intertie Scheduling Conventions

The trade-offs and risks simply are not worth bearing for the limited model accuracy improvements that may or may not be achieved under the GAP-Tie methodology. Based on the discussion and its knowledge of power flows in the West, it is questionable whether any of the CAISO’s stated objectives[1] below are achievable with their GAP-Tie design in the context of EDAM and WEIM operations:

• Significant improvement in power flow and market solution accuracy
• Increased accuracy in congestion management and LMP calculation
• Improved alignment with actual power flow (reduced phantom congestion)
• Reduced need for conforming transmission limits in the market
• Improved alignment with EIM BAA intertie schedules in WEIM

Improving accuracy and alignment between the CRR model and DA model, and between DA and RT, to a level worth pursuing with these changes would require controlling variables and asserting top-down control in the market that CAISO is not capable of or authorized to do under the EDAM design. Without having that control, the accuracy and alignment may in fact be worse than if they were not implemented. When that outcome is combined with the other negative impacts to the CRR and RA markets, implementing this functionality would very likely be a net loss for participants.

Overriding the Voluntary Nature of the WEIM

CAISO’s GAP-Tie methodology and associated intertie scheduling conventions appear to undermine the voluntary nature of the WEIM. As affirmed by FERC, entities with load, generation, or transmission in a WEIM BAA have the right to have only limited interaction with the WEIM. Through base scheduling their resources and continuing to use their contract-path and network transmission rights to support transfers, they are exposed only to imbalance-based charges and certain uplift and offsets allocations that their BAs and TSPs choose to pass on to them. The model presented by the CAISO, however, implies that WEIM will transition to being an involuntary market at EDAM go-live for any entity wishing to deliver energy to an EDAM BAA, whether the CAISO’s or another. As presented, it appears bilateral transfers from a WEIM area to an EDAM area would have a lower priority than in-market optimized transfers and would be exposed to hurdle rates. Moreover, it appears entities holding transmission rights between WEIM areas and EDAM areas would have to register those rights and use them exclusively within the CAISO markets as a comingled set of transfer resources. While these and other aspects of the proposal undoubtedly pull the WEIM and EDAM areas into tighter dependence on each other and may achieve some dispatch and transfer efficiencies, they do so at the cost of disrupting forward contracting and adding significant process burdens for all involved – generators, loads, and the BA/TSPs. If this was to be part of the EDAM implementation effort, it should have been discussed in 2022-23, or stakeholdered as a separate initiative once conceived as an implementation solution. It was not, and forcing this change on the entire WEIM community with just seven months to triage, test, and implement associated changes on non-CAISO systems is simply unworkable.

Disconnect in Understanding of Existing Markets

Aspects of CAISO’s implementation plan appear to reveal a disconnect in CAISO’s understanding of the breadth and depth of forward and spot bilateral financial and physical markets in the West, and how those markets are leveraged to maintain reliability and reduce rate-increase pressure.

Considerations for firm energy and/or renewables-attributes transactions generally include relying on some of the following:

• Using forward index-based, trading hub price discovery to inform deal pricing and risk management;
• Investing in forward physical or financial transmission rights to mitigate or benefit from physical delivery risk and financial exposure;
• Leveraging common transaction elements to ensure entities can move in and out of positions and trade products without making every agreement and buy/sell location, attributes, expectations, and quantity custom;
• Understanding applicable market rules over the term of the contract to mitigate compliance and dry-hole risk, and the risk of having to litigate or renegotiate existing provisions; and
• Relying on inter-regional trade to make the most of assets and spread weather and outage risks to a broader area.

It would be good for CAISO and stakeholders to engage with each other around these cross-market fundamentals and dependencies so greater understanding can be gained around what is likely to happen if, for example, a change is made to markets that undermines the integrity and liquidity of index-based trading hub activity.

Assessing the Feasibility of Proposed Functionality

CAISO should give stakeholders an opportunity to present and stress-test sample transactions, assumptions, and data-dependencies against CAISO’s implementation model for EDAM and DAME. This testing needs to include an assessment of the feasibility of completing all the necessary steps in various new processes within the time available and the cost of doing so. For example, during the November 5 meeting, TEA’s preschedule activity for the next operating day included engaging with twenty-two Western BAs and their TSPs to approve the tags required to effect its DA transactions and fulfill its CAISO market awards. TEA would welcome transitioning this activity to full RTO operations; however, that's not what is on the table for 2026-27, and the practical impacts of living between a bilateral and a fully-organized world need to be accounted for in EDAM implementation. 

Known-Unknowns if the GAP-Tie Functionality is Pursued

If CAISO decides to move forward with its GAP-Tie functionality, more information needs to be shared with stakeholders and more time needs to be taken to troubleshoot and test various scenarios and concepts. At a minimum, CAISO needs to improve its data availability around the changes as soon as possible, and should ensure that all data is available to all market participants. CAISO should publish the intended GAP-Tie mapping and show any on-/off-peak or seasonal differences in defense of that mapping as the two slides included in the November 5-6 presentation are not detailed enough to give stakeholders confidence in CAISO’s choices. CAISO also should clarify whether the GAP-Tie mapping relative to existing intertie points and 2026 annual award positions will be 1:1 or in some way spread across nodes in some instances. Further, CAISO should attempt to quantify the impact to underfunding that these model changes will deliver and be prepared to follow up on that in ongoing CRR Enhancements reporting and future work. And CAISO should discuss the bidding rules and impacts associated with bidding at a G-GAP vs. D-GAP vs. C-GAP as compared to a resource-specific bid in a WEIM or EDAM area, and whether and how certain bids may or may not be subject to mitigation and off-system sales (i.e., DNR) FERC rules where others may not, as well as whether entities would be right to include lost basis value in their bids or sunk transmission costs as a cost component. Included in that should be an explanation of whether GAP-Tie bids are limited to only those entities that hold transmission rights to a CAISO or EDAM BAA, or to wheel through an EDAM BAA, prior to the market run. CAISO should also discuss whether the model for PacifiCorp and Portland General’s intertie transactions will cause pricing anomalies where the D-GAP may electrically overlap or share facilities with a modeled internal constraint on an EDAM system.

These are just a handful of the many questions that come to mind when considering the myriad of impacts moving to a GAP-Tie methodology for transactions that today are effected using the simple contract-path, one-part price-quantity pair bid conventions that have been in place for at least 15 years and that are foundational to power contracts, risk management, hedging, and other market activities related to moving power in to and out of the CAISO BAA.

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About TEA:

The Energy Authority is a nation-wide, non-profit, public-power owned provider of wholesale energy market services. In the West, TEA has partnered with load serving entities inside the CAISO BAA and those in external EDAM and WEIM BAAs to leverage CAISO’s markets to return value to their end-use consumers from their investments in generation and transmission assets. TEA has also partnered with the same to leverage the two SPP markets, RTO-Expansion and Markets+, which are going live in 2026 and 2027 respectively. Given the geographical diversity of its clients, TEA is to an extent on every side of every market design issue. TEA’s participation in these efforts is focused, therefore, not on biasing market outcomes in the direction of supply vs. demand interests, or influencing entities’ organized market decisions, but on CAISO and SPP developing practical solutions that enhance DA and RT market efficiency without undermining other aspects of the complex near- and long-term energy markets its customers engage with to meet their load-service and least-cost planning goals.

[1] https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-Extended-Day-Ahead-Market-Implementation-Workshop-Nov-5-6-2025.pdf - at p.10

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

TransAlta Energy Marketing (U.S.) Inc. (TEMUS) appreciates this opportunity to submit comments in response to implementation details of the California Independent System Operator’s (CAISO) Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy (RA) treatment, and intertie implementation.

TEMUS also appreciates CAISO’s responsiveness to stakeholders concerns regarding the significant and unanticipated changes to current market practices raised in the CAISO’s workshops on intertie scheduling and resource adequacy imports in EDAM. As explained in our previous comments, the concepts presented in the November 4 paper and the workshops were very complex and substantially changed TEMUS’ understanding of the EDAM design.

While the detailed explanation of the power flow modeling behind the intertie framework provided some clarity regarding market optimization, TEMUS continues to have many questions regarding implementation and the harmonization with current commercial practices. In addition, to-date the CAISO and PacifiCorp’s (PAC) implementation efforts have focused on preparing Balancing Area Authorities (BAAs) and their embedded generation and load. TEMUS urges the CAISO to widen this scope to include all market participants. The prioritization of load and generation is understandable but transmission users and marketers play an important role in supporting market efficiency and resource adequacy.

Before the looming go-live date of May 2026, TEMUS asks that the CAISO:

1. Hold stakeholder workshops focusing on implementation for “other” market participants, including transmission users and marketers.
2. Compile a complete searchable database of all questions posed by stakeholders with associated answers to deepen understanding of the new processes. TEMUS has observed that stakeholder questions posed during workshops and submitted comments ask for implementation detail that delve much deeper than what is provided in the EDAM “FAQs”.
3. More timely response to submitted CIDI tickets. TEMUS has several open CIDI tickets that have been waiting for response for weeks. Some of TEMUS’ outstanding questions include:
   1. Some bilateral deals originate in real time and therefore would not warrant interaction with the EDAM market. It is unclear how these real-time bilateral deals are expected to occur in 2026 between non-Energy Imbalance Market (EIM) or non-EDAM market participants and EDAM BAAs. When PAC joins EDAM in 2026, more detail is needed around how real-time bilateral deals will change, including changes to the existing settlements processes.
   2. It is unclear from the November workshops how intertie interactions with non-CAISO BAA (CISO) EDAM BAAs will be cleared and settled based on the neighboring Default Generation Aggregation Point (DGAP)-tie pair. More details and examples around how bidding, scheduling, and settlements will work during the 2026 transitional period at non-CISO EDAM interties are needed.
   3. It remains unclear how intertie bidding, scheduling, and settlements are changing in 2026 for CISO interties (excluding MDWP and CRAGVIEW). The November workshops indicated that 2026 will be a transitional year during which there are no changes to the current Market Redesign & Technology Upgrade (MRTU) processes for CISO interties in both day-ahead (DA) and real-time (RT) markets (excluding MDWP and CRAGVIEW). A detailed explanation of the new process posted publicly for all stakeholders is needed to confirm how bidding, scheduling, and settlements are changing in 2025 for CISO interties.
4. Direct meeting with the EDAM Market Simulation team for live troubleshooting during submission or validation if TEMUS has encountered unresolvable issues.
5. Greater alignment regarding implementation and requirements between EDAM BAAs and the CAISO. TEMUS has received several pieces of conflicting guidance from EDAM BAAs and the CAISO, with each redirecting TEMUS to each other for resolution.

TEMUS appreciates CAISO’s willingness to continue open dialogue on these important issues, and in upcoming workshops, requests that CAISO share more information regarding price formation and impacts on market and commercial practices for all market participants.

1. Please share any comments your organization has on the implementation details of the Extended Day-Ahead Market (EDAM), including but not limited to Congestion Revenue Rights (CRRs), Resource Adequacy treatment, and Intertie implementation.

WPTF appreciates the opportunity to provide these brief comments on the EDAM Implementation meetings held in November 2025. These meetings addressed important details regarding how participants will transact at intertie locations under EDAM and, equally important, how the market will optimize submitted offers. As noted during the discussions, many of the changes presented extend well beyond the implementation details of existing EDAM policy and will significantly affect market participation, bilateral transactions and contracts, and commercial operations.

We appreciate that the CAISO acknowledged the concerns raised by stakeholders during the initial August meeting and convened additional meetings in November to continue the design discussion. We also thank CAISO staff for making themselves available to answer outstanding questions and to consider stakeholder concerns.

While we value these additional engagement efforts, further discussion is still needed given the broad and significant implications this change will have on the western energy market. WPTF therefore supports CAISO’s plan to defer filing the Tariff Clarification until early 2026 and to hold additional stakeholder meetings to help refine and clarify what will be implemented on May 1, 2026, particularly with respect to participation at interties.

We request that the final implementation design strive to ensure that the market continues to optimize all offers in a least-cost manner, produces appropriate and reliable pricing, and preserves, to the extent feasible, current scheduling and bidding practices and functionality, with consistency between the day-ahead and real-time markets.