Comments on Issue Paper and Straw Proposal

1. Please provide your organization's comments on the Interconnection Service Capacity and Deliverability Retention for Non-Operating Generating Facilities Straw Proposal and April 6 meeting discussion

I. Introduction and General Position

The Bay Area Municipal Transmission group (BAMx)^[1] appreciates the opportunity to comment on the Interconnection Service Capacity and Deliverability Retention for Non-Operating Generating Facilities Straw Proposal, dated March 30, 2026, and April 6, 2026 meeting discussion. BAMx generally supports the direction of the Straw Proposal. The recommended actions appropriately address prolonged retention of unused interconnection service capacity and deliverability, which can otherwise be assumed in interconnection and transmission planning studies and contribute to unnecessary long-lead and costly reliability or deliverability network upgrades. This approach aligns with BAMx’s objective of supporting necessary and cost-effective transmission investments, while opposing unnecessary, excessive, or inefficient transmission upgrades that increase costs to ratepayers without commensurate reliability, policy or economic benefits.

II. Policy Alignment and Conceptual Support

BAMx agrees with CAISO’s core premise that extended non-operation of generating facilities—while retaining interconnection service capacity and deliverability—can distort planning assumptions by reserving capacity that may not reasonably be expected to return to service. (Straw Proposal §§1–2; Presentation Slide 6). Including such resources in base-case assumptions can affect study outcomes and increase the likelihood that network upgrades are identified to accommodate capacity that may ultimately remain unused.

BAMx therefore supports CAISO’s proposal to establish clearer expectations and timelines for generator owners to return facilities to service, pursue repowering, or enter the interconnection queue, with defined consequences where no action is taken. (Straw Proposal §3; Presentation Slide 7).

III. Requests for Clarification and Additional Information

A. Empirical Basis and Planning Impacts

To further inform stakeholder evaluation of the proposal, BAMx requests that CAISO provide data on the number of non-operating resources, including megawatt capacity, that have materially affected transmission or deliverability upgrade outcomes in recent interconnection studies or Transmission Planning Process (TPP) cycles. (Straw Proposal §1; Presentation Slide 6). Such information would help stakeholders appreciate the gravity of such identifiable planning inefficiencies in practice.

B. Distinguishing Speculative Retention from Legitimate Long-Term Outages

BAMx requests clarification on how CAISO intends to distinguish speculative retention of interconnection service capacity and deliverability from legitimate long-term outages due to factors outside a generator owner’s control including but not limited to, permitting challenges, equipment availability, financing constraints, labor constraints, and/or complex repowering efforts. (Straw Proposal §3; Presentation Slides 7–8).

In this context, BAMx also encourages CAISO to consider whether a requirement to submit a retirement or mothball affidavit after 12 consecutive months on outage is necessary in all circumstances. Certain forced outages—such as those resulting from major transmission equipment failures or other long-lead-time equipment replacements—may reasonably extend beyond one year despite diligent and commercially reasonable efforts by the generator owner to repair the facility and return it to service. Where a generator owner can demonstrate active repair efforts and a credible plan to return a resource to service within a reasonable timeframe (e.g., two to three years), BAMx requests that CAISO consider allowing such facilities to remain in outage status without requiring formal mothball designation. This flexibility would reduce unnecessary administrative burden while preserving CAISO’s visibility into resource status and would not undermine the proposal’s underlying objective of preventing speculative retention of interconnection service capacity and deliverability.

Clear articulation of the criteria or indicators CAISO will use in making this distinction, as well as the degree of discretion available to account for individual circumstances, will be important to ensure that bona fide repowering efforts are not inadvertently discouraged.

C. Treatment of Resources Already Offline

Finally, BAMx also requests clarification regarding how the proposed timelines would apply to generating facilities that were already offline for extended periods prior to the effective date of the tariff changes. (Straw Proposal §3; Presentation Slide 7). Specifically, BAMx seeks clarity on when the relevant compliance ‘clock’ would begin for such resources and whether transition provisions or initial compliance windows will be provided to avoid retroactive effects.

IV. Conclusion

BAMx supports CAISO’s efforts to better align retention of interconnection service capacity and deliverability with actual resource development and operational intent. The Straw Proposal represents a constructive step toward improving planning efficiency and protecting ratepayers from unnecessary transmission costs. (Straw Proposal §3; Presentation Slides 6–8). Subject to the clarifications requested above, BAMx looks forward to continued engagement as CAISO refines the proposal and develops final tariff language.

[1] BAMx consists of City of Palo Alto Utilities and City of Santa Clara, Silicon Valley Power.

1. Please provide your organization's comments on the Interconnection Service Capacity and Deliverability Retention for Non-Operating Generating Facilities Straw Proposal and April 6 meeting discussion

The California Community Choice Association (CalCCA) appreciates the opportunity to comment on the Interconnection Service Capacity and Deliverability Retention for Non-Operating Generating Facilities Straw Proposal (Straw Proposal). CalCCA supports the CAISO’s intention through this initiative as set forth in the Straw Proposal to clarify a generating facility’s rights and obligations to retain deliverability and interconnection service capacity rights. New deliverable generation capacity is needed to support reliability and the clean energy transition, but existing deliverability is scarce. The Straw Proposal, which contemplates the release of deliverability when a facility retires, will enable existing unused deliverability to be reallocated to projects that can use it.

In the Draft Final Proposal, the CAISO should include language describing the process for releasing deliverability after a generating facility is considered “permanently retired.”^[1] The Straw Proposal defines the process for classifying a resource as permanently retired and states that upon doing so, it will “releas[e] the associated interconnection service capacity and deliverability back into the system to become available to others.”^[2] CalCCA understands this to mean that: (1) the released deliverability will be included in the Transmission Plan Deliverability (TPD) Zones used for the interconnection request intake process to identify zones where planned or existing TPD exists; and (2) the released deliverability will be allocated to projects using the TPD allocation methodology established in the 2023 Interconnection Process Enhancements (IPE) Track 3 and IPE 5.0 stakeholder processes. The Draft Final Proposal should confirm CalCCA’s understanding to clarify how released TPD will be incorporated into the TPD zones and allocated to new projects.

[1]               Straw Proposal, at 9.

[2]               Ibid.

1. Please provide your organization's comments on the Interconnection Service Capacity and Deliverability Retention for Non-Operating Generating Facilities Straw Proposal and April 6 meeting discussion

The California Department of Water Resources – State Water Project (CDWR-SWP) thanks the California Independent System Operator (CAISO) for the opportunity to comment on the CAISO’s Interconnection Service Capacity and Deliverability Retention Straw Proposal.

The CDWR-SWP is in support of the expanded provisions in the repowering process/ interconnection request process regarding adding the seven-year timeline for replacement generation as well as the Commercial Viability Criteria (CVC) and GIA Default Provision checks should the project not be completed within the seven-year timeline. Allowing flexibility in construction timelines for replacement generation beyond the seven-year timeline provided in this straw proposal is important so long as the project is documenting commercial viability through their engineering and project management in addition to demonstrating active engagement in construction and achieving identifiable milestones.

1. Please provide your organization's comments on the Interconnection Service Capacity and Deliverability Retention for Non-Operating Generating Facilities Straw Proposal and April 6 meeting discussion

Calpine appreciates the opportunity to comment and supports CAISO’s objective to prevent inactive resources from holding interconnection capacity without a clear return-to-service path or redevelopment viability. The proposal moves in the right direction but needs clearer limits on scope and timing to avoid unintended impacts on existing resources and repowering efforts. The tariff should apply prospectively, preserve interconnection rights for resources acting under prior approvals, and provide clear rules for repowering pathways. The changes below focus on adding clarity, maintaining flexibility, and avoiding outcomes that undermine investment certainty.

Prospective application and historic retirements

The proposal does not state whether the new timelines apply to facilities already offline. We believe CAISO’s intent is for the contemplated tariff rules to apply prospectively only, and not retroactively to resources that previously came offline.  Retroactive application would also run afoul of the prohibition on retroactive ratemaking.  However, the proposal should make this clear.

Calpine supports prospective application only. Resources that retired, mothballed, or ceased operations under existing tariff and BPM frameworks should not face retroactive loss of interconnection service or deliverability. The tariff should clearly distinguish future non-operational events from existing retirements and outages.

We encourage CAISO to commit to reviewing the circumstances around existing non-operational units on a case-by-case basis so that resource owners working on advancing projects do not face loss of interconnection rights. Applying this set of new tariff provisions to resources in the midst of pursuing repowering projects risks unintended loss of rights that may have been preserved through CAISO review and approvals under BPM flexibility.  During the stakeholder discussion, CAISO indicated that it may address this concern during the tariff development following the finalization of the proposal. Calpine believes this aspect should not be left to the tariff development process.

Online resources utilizing deliverability and repowering CVC requirements

Calpine hopes to ensure the proposal will allow an operating resource seeking repowering to qualify the associated repowering interconnection request to remain eligible to stay in the queue. Specifically, Calpine recommends that the proposal also include clarification on this aspect to clearly state that an existing operating resource that is actively using or marketing its’ deliverability satisfies the Repowers’ Commercial Viability Criteria (CVC) while the repowering effort is underway. Repowering viability should not be in question while the operating unit is available for service.

For operating or non-operating units seeking repowering, the seven-year limit for repower interconnection requests that trigger CAISO’s CVC requirements should also be clarified. CAISO should consider confirming in its proposal that it will continue to apply a case-by-case review approach for repower requests that may be delayed beyond the 7-year window due to circumstances outside of the resource owner’s control. The proposal should explain how Commercial Operation Date (COD) extensions and phased construction are treated.

Repowering clarifications; technology changes, timing, and MMA versus queue entry rules

The tariff should explicitly confirm that a repower from gas or thermal units to battery storage may proceed through the repower or modification process without entering the interconnection queue, consistent with existing Business Practice Manual (BPM) provisions. The straw proposal does not state this clearly, although CAISO alluded to this treatment during the stakeholder call.

The intent of two-year repowering window proposal should be further clarified. As written, it could be unclear whether this is a filing requirement for a Material Modification Assessment (MMA) or Interconnection Request, or a construction deadline. Calpine believes CAISO’s intent is to require submission of a repower MMA or Interconnection Request within two years, not completion of construction. The proposal and respective tariff should state this clearly and allow reasonable flexibility for permitting and development delays.

The proposal should also define when a post-COD modification is permitted versus when a repowering queue request is required. The tariff should specify when an MMA is sufficient and when queue entry is required so owners know when interconnection service and deliverability remain protected.

Finally, CAISO should clarify what starts the compliance clock. The proposal should define whether the trigger is the last date of commercial operation, outage submission entry in OMS, or submission of a retirement or mothball affidavit.

1. Please provide your organization's comments on the Interconnection Service Capacity and Deliverability Retention for Non-Operating Generating Facilities Straw Proposal and April 6 meeting discussion

1. In Section 3 (Proposal) of the Retention of Interconnection Service and Deliverability for Retirements and Repowers Straw Proposal, dated March 30, 2026, CAISO states that it “intends to limit the amount of time a resource can continuously be on outage in the OMS system to 12 months.”  CAISO further states that “resources in outages longer than 12 months in length – including through multiple consecutive outages – would need to go through the retirement/mothball process before returning to service (if so desired).”  In the current environment, it is common that a resource owner’s ability to acquire key electrical equipment and other material may be delayed for an extended period of time primarily due to supply chain challenges.  NCPA believe that a 12 month period is too short.  NCPA suggests that the period of time during which a resource can continuously be on outage in the OMS system be extended to 36 months, so long as the resource owner provides CAISO evidence of its active effort to repair and return the resource to service during that time.  Requiring a resource to either retire or apply for mothball status would create unnecessary and inefficient administrative burdens for a resource owner that is actively working to repair a resource with the goal of returning such resource to service as soon as reasonably possible.  Based on NCPA’s practical experience, key electrical equipment and other materials, such as transformers, hydroelectric runners, replacement rotors, and other major or key pieces of equipment now commonly take more than 1-year to replace based on limited supply.  NCPA recommends that CAISO add a “repair in progress” category to this proposal to account for extended but active maintenance activities.  NCPA fully understands CAISO’s desire to free up deliverability and prevent unnecessary network upgrades by removing truly idle units, but if an resource owner is diligently working to fix a unit and is delayed due to real supply chain issues or other delays outside of its control, CAISO needs to provide additional time to complete such repairs prior to requiring the resource owner to mothball or retire the resource.

2. NCPA would like to better understand CAISO’s statements about the deliverability associated with GIAs for units that pre-existed CAISO. If the CAISO is contemplating a change in treatment for such units on outage, NCPA believes that such units should have a reasonable period of time from the Effective Date of the tariff change to pursue repowering or retirement. A reasonable period of time would be seven years, provided that the owner can demonstrate that it is taking concrete steps to pursue repowering. Seven years is consistent with the Straw Proposal statement that “If a generating facility repowers or submits a new interconnection request, the replacement generation must come online within seven years from when the outage began,” with the possibility of extension beyond seven years based on CVC.

3. Regardless, NCPA opposes setting any hard and fast deadlines for submitting retirement affidavits, repower requests, or returns to operation. For example, CAISO’s proposal to allow a unit to remain on outage for a maximum of 12 months is unreasonable given uncertainties and supply chain constraints. Generators should be able to retain their deliverability provided they are providing evidence that they are taking reasonable steps toward restoration.

1. Please provide your organization's comments on the Interconnection Service Capacity and Deliverability Retention for Non-Operating Generating Facilities Straw Proposal and April 6 meeting discussion

PG&E supports CAISO's efforts to formalize the process around facilities with extended outages or repowering requests, and to move the current BPM language into the tariff.   

PG&E requests clarification with respect to how this initiative would apply in the case of existing facilities that are already on an extended outage (but intend to return to operation).   Would the notification timelines apply retroactively from the original date of the outage?