Comments on Comments on Working Group 3/26

1. Please provide your organization’s overall feedback in response to the March 26, 2025 GHG Coordination working group call.

The Salt River Project Agricultural Improvement and Power District (SRP), Arizona Public Service (APS) and Tucson Electric Power (TEP), collectively identified as the Arizona Utilities, appreciate the opportunity to comment on the March 26 GHG Coordination Working Group meeting. The Arizona Utilities support CAISO's continued work to develop a flexible accounting and reporting framework that accommodates both state-mandated GHG requirements and voluntary corporate GHG reduction goals.

The Arizona Utilities support a flexible emissions allocation approach (Options 1a-1c) for excess generation and believes accurate residual rate reporting is essential. The Arizona Utilities support encourage CAISO to avoid the use of climate region definitions that may result in inequitable treatment or market distortion. The Arizona Utilities also support further discussion on how CAISO will determine excess generation for the residual rate, including whether entities should submit load data or directly identify excess generation. The Arizona Utilities support aligning the definition of null power with the SPP Markets+ definition. Additionally, the Arizona Utilities requests that entities be provided the flexibility to opt out of receiving a report, since it may not align with their internal accounting needs or sustainability goals.

Arizona does not have state-mandated GHG emission reduction goals. SRP’s goals are set and monitored by its governing Board of Directors.

2. Please provide your organization’s feedback on the presentation from WA UTC on CETA.

The Arizona Utilities appreciate the WA UTC providing an overview of CETA to help inform the design of the accounting and reporting framework. It is important that the greenhouse gas market design meets the requirements of state regulatory programs like CETA, as well as entity-specific needs that are voluntary, and also avoids any cost-shifts to states or entities that have voluntary corporate GHG reduction goals in place. By providing this type of public information to stakeholders, it will help ensure that the design meets the needs of state regulatory programs and entities with voluntary corporate GHG reduction goals in the West. Additionally, it will be important to maintain flexibility in any business practice manuals or protocols that are developed as markets evolve.

3. Please provide your organization’s overall input on key considerations with the accounting and reporting approach.

The Arizona Utilities believe that the key considerations with the accounting and reporting approach are:

• Equity between entities that have state mandates and those that have voluntary corporate GHG reduction goals.
• Flexibility to opt out of receiving a report if the report does not meet accounting needs.
• Ability to select and order resources when determining which generation is counted toward an entity’s emissions and what goes to the residual rate
• Consistency in reporting the residual emission rate among all entities. 
• Concerns with the concept of a climate region which could impose unnecessary complexity and impact entities based on varying requirements, resulting in potential cost shifts or policy disputes and administrative burden. The Arizona Utilities do not see a clear need for defining climate regions.
• Accuracy of emissions accounting. The Arizona Utilities are concerned that Options 2 and 3 for identifying excess energy would omit useful data and would be less accurate than Option 1.
• Granular data reporting rather than a single metric. Entities need the ability to use the underlying data to calculate metrics that are applicable to their reporting needs, for example, the residual mix. The Arizona Utilities prefer that the Report Total is provided with hourly granularity. Additionally, it is also critical that the data that is shared outside of the confidential report be publicly available or, alternatively, aggregated in a manner that it does not implicate one entity.
• Ability to identify which resources and loads are relevant for generating a report that meets the needs of state regulatory programs and entities with voluntary corporate GHG reductions goals.

4. Please provide your feedback on how the Accounting and Reporting approach should handle allowing an entity to associate MW and emissions from excess generation to their report (options presented on slides 19-25) versus what should feed back into the residual rate data set and/or residual rates. Please also share your organization’s perspective on how the ISO could obtain information on what should feed into the residual rate from reporting entities.

The Arizona Utilities agree with the CAISO’s straw proposal leaning to allow entities to choose from Options 1a-1c to determine how to associate MW and emissions. This option would align both markets in the West and would give entities flexibility in how to determine the excess, which could differ due to state policy or corporate goals. This option is preferred over Option 2 or Option 3 because it will capture all of the emissions providing a more accurate residual emission rate. The Arizona Utilities would like more information and discussion in a future working group on the options available for providing CAISO with the information for “excess generation” (option 1 or 2 on slide 25) and how this would interact with CAISO’s straw proposal leaning toward allowing entities to choose from options 1a-c to determine excess.  

The Arizona Utilities are open to limiting how often entities can change their approach but recommends that entities be given a chance to switch within a reasonable and practicable time period, especially as entities learn more about this new report.

In regards to the role of “state regulators”, different states have varying regulatory frameworks and may have limited knowledge of energy markets. Further discussion should address the role of regulators in this context.

5. Please share your organization’s feedback on information that should be captured when associating a resource to an entity’s report. For example, null power, jointly owned unit arrangements, and verification between an SC and the reporting entity.

The Arizona Utilities believe that CAISO will need to collect data to create an accurate report.  Some of this data will include:

• Resources to be associated with the reporting entity.
• Bilateral contracts.
• Jointly owned unit (JOU) ownership, with flexibility to use schedules provided to the resource operators rather than an ownership percentage.
• Null power
  • The Arizona Utilities agree with SPP Markets+ definition of null power.  Extending this definition to the CAISO markets would allow for consistency across the West.  For reference, the definition for Null Power in Markets+ is: Energy designated by a Reporting Entity indicating that the Renewable Energy Certificates and/or nonpower attributes have been separated from the Energy and retained by the Reporting Entity or sold to a third party. Nothing in these protocols requires a Reporting Entity to designate power as null.

The Arizona Utilities are open to a verification requirement for any contracts or JOUs. The Arizona Utilities are a proponent of a standardized REC accounting methodology among the entities in the West and would like a future GHG meeting to discuss standardization within the market.

With respect to Non-Participating entities, the Arizona Utilities are interested in more discussion on the pros and cons of assigning over a threshold vs. not assigning MW and emissions.

1. Please provide your organization’s overall feedback in response to the March 26, 2025 GHG Coordination working group call.

BPA appreciates the progress made on the GHG accounting and reporting approach.

2. Please provide your organization’s feedback on the presentation from WA UTC on CETA.

BPA appreciates the WA UTC taking the time to present. 

BPA recognizes that the issue of double counting and null power varies across states, and even different programs within states. As a wholesale power marketer with sales across many states, BPA emphasizes the importance of considering all state policies in the market tracking and reporting as it relates to null power.

3. Please provide your organization’s overall input on key considerations with the accounting and reporting approach.

BPA supports the CAISO’s recognition that more flexibility is needed in the GHG tracking and reporting as each entity has different requirements stemming from utility needs and state program compliance.

4. Please provide your feedback on how the Accounting and Reporting approach should handle allowing an entity to associate MW and emissions from excess generation to their report (options presented on slides 19-25) versus what should feed back into the residual rate data set and/or residual rates. Please also share your organization’s perspective on how the ISO could obtain information on what should feed into the residual rate from reporting entities.

BPA supports option 1 (slide 20) with the ability for the entity to choose between a-c for the method of crediting emissions back to the residual rate.  BPA supports a method for determining a residual rate for those entities/states that would use it in their GHG accounting.  The flexibility for each entity to determine the appropriate method is critical; it acknowledges that different entities have different requirements and needs.

On slide 24 of the presentation the CAISO asks if there should be limits on a reporting entity changing the method used.  BPA suggests that a reporting entity should be able to change the method at least annually.

On slide 25 of the presentation the CAISO asks what data a reporting entity should provide to enable the CAISO’s report.  At this time, BPA does not have a strong opinion on option 1 versus option 2.  BPA would like to hear from state regulators who intend to use this data whether there is a preference.  Option 1 provides a more unified and likely transparent approach to calculating what emissions should be included in the residual rate.  Option 2b leaves that calculation up to the reporting entity, which provides the reporting entity with greater control in determining what emissions are included in the residual rate, but may not provide as much transparency.

On slide 26 of the presentation the CAISO asks what data on the residual rate should be published.  BPA supports the phased approach the CAISO proposes but notes that the CAISO should be willing to make the full data set available if a reporting entity would like to review its individual calculation.

5. Please share your organization’s feedback on information that should be captured when associating a resource to an entity’s report. For example, null power, jointly owned unit arrangements, and verification between an SC and the reporting entity.

BPA agrees that a reporting entity will need to provide details on contracts for the CAISO to accurately capture emissions for the residual rate (slide 27). 

On slide 28 of the presentation, the CAISO asks what assumptions should be made for jointly owned units (or multiple contracts for purchase from a generator).  The reporting tool should have the flexibility to capture various contractual arrangements.  In addition to percentage ownership/rights and primary off takers, there are also contingency reserve contracts where a contracting party may be able to call back the energy under certain circumstances.

On slide 29, the CAISO asks what assumptions should be made for nonparticipating entities.  BPA requests that the CAISO reconsider its proposal to not assign emissions from owned resources to non participating entities.   Not assigning emissions from owned resources to nonparticipating entities could have a significant and material impact on the residual rate data.  BPA understands the CAISO does not currently request such information for participants but would encourage the CAISO to consider whether it could obtain such information as part of registration parameters, etc.  Alternatively, public data is available for many major resources that could be used to determine resource ownership.  BPA requests the CAISO further explore how it could obtain such data on at least major resources to provide more accurate residual rate data.

1. Please provide your organization’s overall feedback in response to the March 26, 2025 GHG Coordination working group call.

PacifiCorp believes the accounting and reporting approach is moving with great momentum and anticipates the publication of the straw proposal.  

2. Please provide your organization’s feedback on the presentation from WA UTC on CETA.

PacifiCorp thanks Charlie Inman at Washington Utilities and Transportation for his presentation on the Clean Energy Transformation Act (CETA) and the challenges faced in organized markets with regard to renewable energy credit (REC) based accounting. PacifiCorp believes organized market participation will not impede the overall goal of CETA as the CAISO day-ahead and real-time markets use an attribution process to dispatch resources for states with a price on carbon and, as such, Washington customers have insight into the types of resources that are used to meet demand in the state. However, as presented on, RECs will not be included in the transfer of generation for specified market transactions. According to the newly published redlines UTC draft rules published April 1, 2025, primary compliance can still be achieved through organized market participation, as purchasers can obtain the REC from the specified power outside of the market and bundle to use for primary compliance which is a welcome alteration from previous versions of the draft rules. Draft rules also allow market participants to sell electricity from renewable resources on an unspecified basis and retain the REC for their own CETA compliance, allowing entities like PacifiCorp to maximize the resources participating in the market without risking double counting RECs.

3. Please provide your organization’s overall input on key considerations with the accounting and reporting approach.

PacifiCorp believes REC-based accounting should not be married with emission-based accounting for organized market transactions. Blending the two accounting frameworks creates a distortion between the actual emission intensity of the market footprint. As discussed during the WA UTCs presentation of REC-based accounting, there is no straightforward way to view null power in the organized market context as inclusion leads to double counting concerns and exclusion leads to an inaccurate residual rate. Resources should be reflected within the residual rate market mix at the emissions rate of the generation type, rather than the unspecified or “null” emission factor. In practice, when a renewable resource is offered into the market, PacifiCorp will retain its RECs for its own compliance position in either Washington, California, or Oregon.

4. Please provide your feedback on how the Accounting and Reporting approach should handle allowing an entity to associate MW and emissions from excess generation to their report (options presented on slides 19-25) versus what should feed back into the residual rate data set and/or residual rates. Please also share your organization’s perspective on how the ISO could obtain information on what should feed into the residual rate from reporting entities.

PacifiCorp believes option 1a would be the most just and reasonable approach to ensure that reporting entities are reporting all fuel types that were dispatched to serve load. However, PacifiCorp would like additional discussion on this topic and specifically, the options that do not capture all emissions from the market. Additionally, PacifiCorp needs clarification on the crediting back process described in the matrix. The CAISO posed questions on whether there should be fixed limits on changing the approach from one year to the next and if any, whether state regulators would want to approve the approach used. PacifiCorp will act in accordance with regulatory approval of reporting methodologies resulting from the CAISO GHG working group and believes after the first compliance year, the report should be evaluated after the first year to check whether the report gives the information needed for compliance and reporting needs.  

The CAISO asked for feedback on whether load data from the reporting entity should be communicated to the CAISO or whether a notification on either what was associated with the reporting entity or what should be considered excess. PacifiCorp believes option two is the best option as it allows the reporting entity to inform the CAISO of what excess generation should go back into the residual rate. PacifiCorp also believes this will assuage double counting concerns as the generation used to formulate reporting entity’s individual report will be communicated to the ISO.

5. Please share your organization’s feedback on information that should be captured when associating a resource to an entity’s report. For example, null power, jointly owned unit arrangements, and verification between an SC and the reporting entity.

The CAISO should publish data on what resources are in the residual rate data set rather than producing a voluminous report total which could result in a mismatch of reporting data. Validation of data would be prudent for jointly owned contracts that include length of the arrangement. For market participants who are not participating in the accounting and reporting approach, PacifiCorp believes that assigning over a threshold could provide a good middle ground as there is “known” information to use. 

1. Please provide your organization’s overall feedback in response to the March 26, 2025 GHG Coordination working group call.

Portland General Electric thanks the CAISO for facilitating an informative meeting.

2. Please provide your organization’s feedback on the presentation from WA UTC on CETA.

No comment at this time.

3. Please provide your organization’s overall input on key considerations with the accounting and reporting approach.

PGE thanks the CAISO for clearly articulating some of the major design decisions for the accounting and reporting approach.

4. Please provide your feedback on how the Accounting and Reporting approach should handle allowing an entity to associate MW and emissions from excess generation to their report (options presented on slides 19-25) versus what should feed back into the residual rate data set and/or residual rates. Please also share your organization’s perspective on how the ISO could obtain information on what should feed into the residual rate from reporting entities.

PGE appreciates the options outlined by the CAISO, including an entity’s flexibility of choice in treating MW and emissions in excess of load within an interval to the residual rate. Separately, PGE recommends a limit in how frequently a reporting entity should be allowed to change its excess generation allocation decision, driven in part by the complexity of battery storage charging/discharge across dispatch intervals.

5. Please share your organization’s feedback on information that should be captured when associating a resource to an entity’s report. For example, null power, jointly owned unit arrangements, and verification between an SC and the reporting entity.

PGE supports the CAISO’s objective and believes that this GHG reporting design can accommodate different approaches for accounting for clean energy. 

HB 2021 is designed as a cap on emissions associated with serving Oregon retail load. The rules calculate the emissions based on the characteristics of the underlying source of generation, regardless of renewable energy credits (RECs). PGE recommends that the GHG Accounting Report provide information on the emissions of the underlying source of generation for market purchases.

To ensure the most accurate GHG accounting and reporting, the report’s residual rate should exclude transactions that have been attributed/deemed to other entities to ensure an accurate reflection of the GHG emissions of “excess generation” (as part of the residual market rate), regardless of whether those entities will be using the report.

For questions regarding jointly owned resources and reporting entity and SC, PGE would like to further explore the implications and impact of this to the residual rate. PGE requests clarity on the purpose of verification between an SC and the reporting entity.

1. Please provide your organization’s overall feedback in response to the March 26, 2025 GHG Coordination working group call.

The Public Generating Pool (PGP) appreciates the opportunity to comment on the progress made so far in the GHG Coordination Working Group. In these comments, PGP makes several suggestions with respect to the topics discussed at the March 26, 2025, Working Group meeting. 

2. Please provide your organization’s feedback on the presentation from WA UTC on CETA.

PGP extends our thanks to CAISO staff and Charlie Inman, UTC staff, for providing this overview of issues relating to double counting in the context of CETA. With two of our Washington members—Seattle City Light and Tacoma Power—currently participating in the WEIM, PGP believes that the Accounting and Reporting approach will need to appropriately address CETA’s double counting framework to avoid of the unintended consequence of impairing the use of market participants’ Renewable Energy Certificates (RECs) when CETA goes into full effect in 2030.  

PGP recognizes that Washington’s policy creates a challenge with neighboring states’ policies that do not incorporate RECs into GHG emissions accounting. PGP strongly encourages stakeholders in both Washington and Oregon to consider compromise approaches that consider both states’ policies versus selecting one approach over the other. Since Washington state agencies, including the UTC, have confirmed that the approach to null power adopted in in the Southwest Power Pool (SPP) Markets+ context appropriately addresses CETA’s double counting framework, PGP suggests that it might be helpful for the CAISO GHG Coordination Working Group to receive a deeper dive presentation on the Markets+ adopted approach and the tradeoffs associated with it. To that end, PGP reiterates the offer made in our February 2025 comments to provide this overview and/or work with SPP or other stakeholders to present perspectives on the topic.  

3. Please provide your organization’s overall input on key considerations with the accounting and reporting approach.

Central to PGP’s considerations with the Accounting and Reporting approach are the implementation of safeguards against double counting of both energy and RECs/nonpower attributes, as required under Washington state law. This includes mechanisms by which a reporting entity can designate its owned or contracted energy resources as “null power” and the appropriate reflection of null power in the residual rate/residual rate data set. PGP recommends further discussion within the working group to define when double counting occurs. Approaches that label energy as null but still apply a fuel type and/or emissions factor for calculation in a residual rate may still prove a problematic use of the nonpower attributes in the absence of the associated REC. Further discussion is also warranted with respect to the granularity with which null power data may be published. It may be possible to aggregate null power across timeframes to avoid some of the double-counting concerns while also providing transparent and complete data.  

Under the Markets+ approach, a monthly public GHG report will be published with hourly volumes of null power without the underlying fuel type and emissions profile. On a quarterly and annual basis, a public GHG report will be published with aggregated volumes of null power by fuel type and emissions. The rationale behind this compromise was to enable transparency in terms of the fuel type associated with null power on a quarterly and annual basis while avoiding double-counting risks associated with publishing granular data identifying the fuel type and emissions profile of null power.  

The Markets+ GHG protocol language is attached to the PGP comments for reference.  

4. Please provide your feedback on how the Accounting and Reporting approach should handle allowing an entity to associate MW and emissions from excess generation to their report (options presented on slides 19-25) versus what should feed back into the residual rate data set and/or residual rates. Please also share your organization’s perspective on how the ISO could obtain information on what should feed into the residual rate from reporting entities.

PGP agrees with CAISO staff’s proposed straw proposal leaning of allowing a reporting entity to choose among three sub-options for associating MW and emissions from excess generation to their report: 

• Option 1 – Credit a reporting entity and return “excess generation” to the residual rate 
  • Option 1a – Average the emissions and return to the residual rate 
  • Option 1b – Use a merit stack order and return excess to the residual rate 
  • Option 1c – Allow the user to choose which MW and associated emissions are returned to the residual rate 

The Accounting and Reporting approach should allow a reporting entity to communicate its choice among these three sub-options to the CAISO by some date certain preceding the relevant calendar year for which the methodology selection is being made. For reporting entities who do not select a methodology, excess energy should be contributed to the residual energy calculation using Option 1a.  

PGP is interested in further discussion with respect to accounting for “excess generation” in the residual rate data set, and the options set out on slide 25. PGP appreciates the flexibility reflected in Option 2 on enabling market participants to determine and identify what should be considered excess generation. However, PGP is interested in hearing from others, particularly those who may use the data and/or residual energy for compliance reporting purposes, on whether this flexibility will drive the need for additional data verifications or processes to verify the data submitted by individual entities.  

5. Please share your organization’s feedback on information that should be captured when associating a resource to an entity’s report. For example, null power, jointly owned unit arrangements, and verification between an SC and the reporting entity.

The Accounting and Reporting approach should allow a reporting entity to self-identify owned and contracted resources, including partially owned resources, that should be mapped or associated to that entity’s report. The approach should provide a means for a reporting entity to confirm its self-identified contracted resources with the appropriate Scheduling Coordinator (SC), including SCs that are not themselves reporting entities. Safeguards against double counting of energy should be implemented such that if the CAISO identifies an instance where more than one reporting entity claims the same energy for the mapping or association process, the CAISO has the ability to notify the affected reporting entities as soon as practicable and pause the mapping or association process until the reporting entities resolve their conflicting claims.  

Any definition for “null power” reporting purposes should, at minimum, allow a reporting entity to designate energy for which the RECs or nonpower attributes have been separated from the energy and either retained by the reporting entity or sold to a third party. In keeping with the voluntary nature of participation in the Accounting and Reporting approach, the designation of energy as “null power” should also be voluntary.  

1. Please provide your organization’s overall feedback in response to the March 26, 2025 GHG Coordination working group call.

Six Cities’ Response:  Please see specific comments below.

2. Please provide your organization’s feedback on the presentation from WA UTC on CETA.

Six Cities’ Response:  The Six Cities have no comments on the WA UTC presentation.

3. Please provide your organization’s overall input on key considerations with the accounting and reporting approach.

Six Cities’ Comments:  Subject to further discussion and more detailed development of design elements, the Six Cities generally support further efforts to flesh out the accounting and reporting framework described in the CAISO’s 3/26 presentation.  The Six Cities reiterate their previous comments (i) that any SC ID level data should be reported in the first instance only to the LSEs responsible for load served by the resource in question, with such LSEs having responsibility and authority for further publication or distribution of their own data based on policies or requirements established by the applicable Local Regulatory Authority or other local, state, or federal regulatory authorities having applicable jurisdiction, and (ii) that the CAISO provide a high level estimate of the costs of implementing different approaches for accounting and reporting and a description of alternative methods for recovering the implementation costs for each approach.

4. Please provide your feedback on how the Accounting and Reporting approach should handle allowing an entity to associate MW and emissions from excess generation to their report (options presented on slides 19-25) versus what should feed back into the residual rate data set and/or residual rates. Please also share your organization’s perspective on how the ISO could obtain information on what should feed into the residual rate from reporting entities.

Six Cities’ Comments:  On a preliminary basis and subject to further evaluation and discussion, the Six Cities generally support the approach of allowing flexibility (i.e., choice among approaches 1a-1c as described in the CAISO’s 3/26 presentation) for reporting entities to attribute use of owned or contracted resources to serve their loads versus residual energy.  In general, it seems reasonable to allow load serving entities the option to direct attribution of non-emitting resources they own or control to serving their own loads first, with contribution of excess energy to the residual pool.  It also would seem reasonable to allow a change in the option selected on an annual basis by a pre-established date announced at least sixty days in advance.

5. Please share your organization’s feedback on information that should be captured when associating a resource to an entity’s report. For example, null power, jointly owned unit arrangements, and verification between an SC and the reporting entity.

Six Cities’ Response:  The Six Cities have no comments at this time regarding this aspect of the reporting framework.