Comments on Draft tariff language and May 24, 2022 stakeholder call discussion

1. Please provide your organization's comments on the FERC 881 - Managing Transmission Line Ratings May 24 stakeholder call discussion:

A: General Comments:

The FERC Order 881 implementation timeline is July 12, 2025. While CalWEA strongly supports CAISO’s efforts in this area, we believe that there are immediate steps that can be taken earlier to achieve some of the basic goals of Order 881. We understand that such steps should only involve CAISO implementing simple changes in its systems and operating practices. During the call, a CAISO representative mentioned that CAISO is open to other ideas or recommendations from its stakeholders.

CalWEA proposes one simple change in its operating practices, to take effect before calendar year 2023:  for those transmission facilities where seasonal ratings are available to CAISO from its PTOs, CAISO would use the same temperature forecast used for its DA Market scheduling to determine the relevant seasonal facility rating that would be used for DA Market scheduling (and later for RT Market operation). This process would replace the existing CAISO practice of changing the rating of its transmission facilities based on calendar dates and instead base the rating on the actual ambient temperature forecast.   

B. Presentation comments:

CAISO requested stakeholders’ comments on specific presentation slides. (No comment at this time on slides not listed.) CalWEA’s responses are as follows:

Slide 13 of 20:

Order No. 881 encourages RTOs/ISOs to coordinate implementation of transmission ratings methodologies. CAISO is not proposing to create methodology requirements for participating transmission owners or WEIM Entities.

Do stakeholders have a different view and believe the CAISO must create methodology requirements that apply to participating transmission owners or WEIM Entities?

-           CalWEA’s preference would be that CAISO create methodology requirements that are consistent across its PTOs and WEIM entities.

Slide 14 of 20:

The CAISO will propose to use ambient adjusted ratings in its day day-ahead and real real-time markets.

CAISO will propose to require submission of ambient adjusted ratings by market close to allow time for CAISO validation and market systems to utilize ratings.

Do stakeholders have any perspective on the use of ambient adjusted ratings in the CAISO’s markets or the timing to incorporate ratings?

-           CalWEA strongly supports this CAISO proposal.

CAISO will also propose participating transmission owners validate ambient adjusted ratings prior to submission.

Does this proposed requirement create any stakeholder concerns?

-           CalWEA supports this CAISO proposal provided that it does not lead to unnecessary delays in updating these ratings for CAISO market and system operation.

CAISO will use seasonal rating if data or system issues prevent use of ambient adjusted rating.

-           CalWEA requests that CAISO flag such issues for all stakeholders.

-           CalWEA recommends  using transmission facilities’ seasonal ratings based on the same weather forecast that CAISO uses for its DA Market, rather than based on the season as determined by the calendar. For example, during a summer season, facilities’ winter ratings should be selected when forecasted temperatures are in the cooler winter range. Implementation in 2023 should allow for development of necessary tools for implementation.

Slide 15 of 20:

The CAISO proposes to use ambient adjusted ratings from the real real-time market in its real real-time contingency analysis.

Do stakeholders have any perspective on which ratings to use in RTCA, or potential variance between CAISO and participant RTCAs?

• CalWEA recommends that CAISO use the most accurate method -- ambient adjusted normal/emergency ratings -- during system contingencies.  (No comment on potential variance between CAISO and participant RTCAs.)

The CAISO requests stakeholder comment on the planned utilization of ambient adjusted ratings in remedial action schemes.

• CalWEA likewise recommends that CAISO use the most accurate method -- ambient adjusted normal/emergency ratings -- in its RAS implementation.

Slide 17 of 20:

Order 881 requires the CAISO to implement systems and procedures necessary to allow electronic updates to ratings at least hourly.

• Ratings submitted by participating transmission owners directly into the EMS through SCADA or similar systems

• Use of other electronic systems, such as Inter-Control Center Communication Protocol

Do stakeholders have any perspectives on allowing both functionalities to accommodate PTOs, EIM Entities and RC Customers?

-      CalWEA recommends that both functionalities be allowed because sometimes for certain entities, ICCP is addition/augmentation to SCADA for specific facilities and not a backup/replacement.

Do stakeholders have perspectives on whether the CAISO should include tariff language governing dynamic line ratings, e.g., a definition and language recognizing dynamic line ratings in transmission rating methodologies?

• Since FERC and CAISO will be further exploring DLR implementation in coming years, this may not be necessary. However, one of the directives from Order 881 is for CAISO to prep the system for DLR type data and handling. So, for that purpose, defining DLR now may be helpful.

Slide 18 of 20:

Order No. 881 requires the CAISO to maintain a database of ratings and methodologies on OASIS or another password-protected website.

CAISO proposes to limit this database to ratings and methodologies of participating transmission owners and not include EIM Entities or RC Customers

Do stakeholders have any comments on these compliance requirements the CAISO should consider?

• CalWEA recommends including EIM entities and RC customers for consistency and transparency.

2. Please provide a summary of your organization's comment on the FERC 881 - Managing Transmission Line Ratings draft tariff language:

Minor comments included in uploaded document.

3. Please upload redlined tariff language using the "attachments” field below.

Attached.

1. Please provide your organization's comments on the FERC 881 - Managing Transmission Line Ratings May 24 stakeholder call discussion:

See attached comments.

2. Please provide a summary of your organization's comment on the FERC 881 - Managing Transmission Line Ratings draft tariff language:

See attached comments.

3. Please upload redlined tariff language using the "attachments” field below.

See attached comments.

1. Please provide your organization's comments on the FERC 881 - Managing Transmission Line Ratings May 24 stakeholder call discussion:

EDF-R appreciates the opportunity to comment on the CAISO’s FERC Order No. 881 compliance efforts. EDF-R appreciates the CAISO’s commitment to developing transparent reporting with respect to dynamic line rating changes. EDF-R looks forward to working with the CAISO on its response to the various transmission and efforts that will inevitably result from the Notice of Proposed Rulemaking on Transmission Planning and Cost Allocation and Generator Interconnection RM21-17-000.

It was clear on the May 24 web conference that there are significant technology tasks required to implement a solution. To that end EDF-R requests that CAISO continue to engage stakeholders in the stakeholder process through the development of the Business Requirements Specification (BRS) document as well as the first draft of any Business Practice Manual (BPM) Proposed Revision Requests (PRRs) that are spurred from this effort. EDF-R also requests that the CAISO provide a rough outline of that engagement when the implementation schedule is published in Q3 2022. The CAISO has done this in previous stakeholder efforts, such as the Summer 2021 Readiness effort.

EDF-R agrees with many of the questions on the stakeholder call. The CAISO did not publish a traditional straw proposal for this compliance effort, so EDF-R requests that CAISO publish some kind of stakeholder response document summarizing and responding to stakeholder questions with its July 21 tariff draft.

Questions on the call included:

• How will CAISO ensure information equity between the DA and RT markets? Transmission changes in RT will trigger corresponding changes in market results. As CAISO described in the call, the current system for considering transmission line ratings in DA markets models line ratings that only change every five to six weeks. EDF-R is concerned about the effects of improving RT transmission rating granularity without a correlated change to DA.
  
  Suggestions on the call included a temperature forecast for the next day or temperature forecast for the next operating hour and use the relevant seasonal rating for those transmission facilities in DA scheduling or RT dispatch. EDF-R does not support or oppose that proposal in particular, but appreciated the idea that DA and RT line ratings could be brought closer together than currently proposed.
   
• Given this proposal is that the transmission owners will be calculating ratings and then communicating those to the CAISO, will this proposal come with a discussion on the processes participating transmission owners use similar methodology to identify line rating adjustments? Disparate calculation methodologies could potentially result in disparate market outcomes or congestion that is not objective necessary for reliability.
  
  EDF-R supports the suggestion that the CAISO at a minimum validate dynamic rating submissions.
   
• Will the CAISO perform and publish analysis on the expected impacts of dynamic line ratings on congestion or remedial action schemes? Particularly to the extent that ratings are hard-coded or other limitations are embedded into the software.
  
  EDF-R strongly encourages the CAISO re-activate the RAS review in this forum or in a separate initiative. As a general matter EDF-R is very interested in system congestion and how line ratings and RAS effect that transmission. EDF-R summarized these questions in its comments on the CAISO’s now-inactive Planning Standards – Remedial Action Scheme Guidelines Update. In that initiative CAISO stated that the Generator Contingency and RAS Modeling initiative “has turned out to be more of a challenge than was expected and is considered a work in progress.” EDF-R encourages the CAISO to take a holistic look at known RAS challenges in a timely matter, as the implementation of dynamic line ratings may further complicate future RAS reviews.

2. Please provide a summary of your organization's comment on the FERC 881 - Managing Transmission Line Ratings draft tariff language:

EDF-R appreciates the opportunity to comment on the CAISO’s FERC Order No. 881 compliance efforts. EDF-R appreciates the CAISO’s commitment to developing transparent reporting with respect to line rating changes.  The CAISO did not publish a traditional straw proposal for this compliance effort, so EDF-R requests that CAISO publish some kind of stakeholder response document summarizing and responding to with its July 21 tariff draft. Finally, EDF-R encourages the CAISO to take a holistic look at known RAS challenges in a timely matter, as the implementation of dynamic line ratings may further complicate future RAS reviews.

3. Please upload redlined tariff language using the "attachments” field below.

None at this time.

1. Please provide your organization's comments on the FERC 881 - Managing Transmission Line Ratings May 24 stakeholder call discussion:

PG&E has organized its comments in a manner that responds to the questions posed by CAISO staff in its May 24 workshop presentation.

1. The CAISO does not intend to modify the Transmission Control Agreement:  The TCA imposes a requirement on participating transmission owners to provide in a format acceptable to the CAISO applicable ratings of all transmission lines and associated facilities as well as changes to those ratings
   1. Request: Do stakeholders have a different view and believe modifications to the TCA are necessary?

PG&E Response: PG&E agrees with CAISO that no modification to the TCA is necessary.
 

2. The CAISO does not intend to impose additional tariff requirements on WEIM entities but will account for WEIM Entities’ rating methodologies:  Section 29.17 of the CAISO tariff require each WEIM Entity to submit transmission service information to the CAISO
   1. Request: Do stakeholders have a different view and believe changes to section 29 of the CAISO tariff are necessary?

PG&E agrees with CAISO that no additional tariff requirements on WEIM entities are necessary.

3. The CAISO does not intend to impose additional tariff requirements on RC Customers but will account for RC Customers’ rating methodologies:  Section 19.5(b)(2) of the CAISO tariff requires each RC Customer to exchanging data, operating plans, operating procedures, studies, and reports with the CAISO in accordance with the Business Practice Manual for RC Services and applicable RC Operating Procedures
   1. Request: Do stakeholders have a different view and believe changes to section 19 of the CAISO tariff are necessary?

PG&E agrees with CAISO that no additional tariff requirements on Reliability Coordinator (RC) Customers are necessary.

4. Order No. 881 encourages RTOs/ISOs to coordinate implementation of transmission ratings methodologies
   1. CAISO proposes to adapt the pro forma OATT language [and] state that it will coordinate with participating transmission owners in their development of transmission line methodologies
      1. CAISO will also coordinate with participating transmission owners on the development of exceptions and alternate ratings
      2. CAISO is not proposing to create methodology requirements for participating transmission owners or WEIM Entities
         1. Request: Do stakeholders have a different view and believe the CAISO must create methodology requirements that apply to participating transmission owners or WEIM Entities

PG&E supports CAISO’s proposal and looks forward to working with CAISO staff and the other Participating Transmission Owners (PTOs) on coordinating on the development of transmission line methodologies.  One area that PG&E would like to highlight now where coordination will be critical is at transmission tie-points that connect two PTO service areas and ensuring that the methodologies are aligned at these sections.

5. The CAISO will propose to use ambient adjusted ratings in its day-ahead and real-time markets
   1. CAISO will propose to require submission of ambient adjusted ratings by market close to allow time for CAISO validation and market systems to utilize ratings
      1. Request: Do stakeholders have any perspective on the use of ambient adjusted ratings in the CAISO’s markets or the timing to incorporate ratings

PG&E has no comments on this section.

1. 2. CAISO will also propose participating transmission owners validate ambient adjusted ratings prior to submission
      1. Request: Does this proposed requirement create any stakeholder concerns

PG&E requests that CAISO clarify what is meant by “validate” in this proposal and what will be required of PTOs to validate ambient adjusted ratings prior to submission.

6. CAISO proposes to use ambient adjusted ratings from the real-time market in its real-time contingency analysis
   1. CAISO proposes to reflect the most granular ambient adjusted ratings used in the market as part of its RTCA during that same time interval
      1. Request: Do stakeholders have any perspective on which ratings to use in RTCA, or potential variance between CAISO and participant RTCAs?

PG&Es agrees that ambient adjusted ratings from the real-time market should also be used in real-time contingency analysis (RTCA).  Specifically, in accordance with the requirements in the OATT Attachment M and paragraphs 293 and 294 of FERC Order 881, PG&E believes that ambient adjusted emergency ratings should be used for RTCA.  Currently, PG&E manually enters the seasonal summer/winter normal and emergency ratings into State Estimation/RTCA.  PG&E requests that CAISO provide clarity on validation criteria that would determine ambient-adjusted rating (AAR) unusable for both Market and Real-time for reliability and whether PTO’s will be required to switch to seasonal ratings.

1. 1. 2. Request: The CAISO requests stakeholder comment on the planned utilization of ambient adjusted ratings in remedial action schemes

Since RASs are typically installed/designed for a specific set of conditions, PG&E recommends that RAS specific power flow studies be performed to identify any potential impacts associated with the use of AARs in an area where RASs are located.  For example, studies should not be limited to just transmission lines that will use AARs and are associated with a RAS, but if an adjacent line(s) not associated with the RAS uses AARs, studies should be performed to identify the potential impacts to that RAS. 

PG&E supports CAISO’s plan to coordinate with PTOs on implementation of AARs in RASs.  Additionally, if adjustments to RASs are required and such changes constitute a functional modification to a RAS, additional reviews, and approval by the RC (and WECC RASRS) may be required.

7. Seasonal ratings will apply to any long-term transmission service provided by the CAISO
   1. The CAISO is holding working group meetings to foster dialogue on the development of long-term transmission products and reservations, i.e. requests for transmission service more than 10 days in the future
   2. Seasonal rating methodologies would apply to these request for transmission service
      1. Request: Do stakeholders have any comments on how, if at all, the CAISO should address this issue in its Order No. 881 compliance filing.

PG&E agrees with CAISO’s approach to use seasonal ratings for any long-term transmission service (i.e., more than 10 days in the future).  Paragraph 5 of FERC Order 881 requires the use  seasonal  line  ratings  as  the  basis  for  evaluation  of transmission  service  requests  ending more than 10 days from the date of the request.

8. Order No. 881 requires the CAISO to implement systems and procedures necessary to allow electronic updates to ratings at least hourly
   1. Ratings submitted by participating transmission owners directly into the EMS through SCADA or similar systems
   2. Use of other electronic systems, such as Inter-Control Center Communication Protocol
      1. Request: Do stakeholders have any perspectives on allowing both functionalities to accommodate PTOs, EIM Entities and RC Customers.

PG&E recommends that CAISO allow both EMS and Inter-Control Center Communication Protocol (ICCP) functionalities for PTOs, EIM Entities and RC Customers to submit ratings.  Entities may already be using either EMS or ICCP to transmit data to CAISO and requiring the use of a different system may require some PTOs to perform time-intensive upgrades.  In the event the CAISO ultimately decides that only one electronic system should be used for transmitting data, then PG&E recommends ICCP be utilized since there is already a method by which PG&E is sending data to CAISO in real-time.

1. 1. 2. Request: Do stakeholders have perspectives on whether the CAISO should include tariff language governing dynamic line ratings, e.g. a definition and language recognizing dynamic line ratings in transmission rating methodologies

PG&E recommends CAISO not include at this time tariff language governing dynamic line ratings (DLRs) since the issue of requiring use of DLRs, and when, is currently under consideration by FERC via a Notice of Inquiry.  If FERC adopts a rule requiring the use of DLRs, at that time CAISO would likely need to make another compliance filing to update its tariff to align with the definition and use cases in the FERC order.

9. Order No. 881 requires the CAISO maintain a database of ratings and methodologies on OASIS or another password-protected website
   1. Share ratings and methodologies with Transmission Providers, Market Monitor and other entities
   2. Maintain database of ratings used and methodologies as well as exceptions and alternate ratings
      1. Individual records of ratings in effect for each transmission line at which times
      2. Maintain records for 5 years
   3. CAISO proposes to limit this database to ratings and methodologies of participating transmission owners and not include EIM Entities or RC Customers
      1. Request: Do stakeholders have any comments on these compliance requirements the CAISO should consider?

PG&E has no comments on this section.

2. Please provide a summary of your organization's comment on the FERC 881 - Managing Transmission Line Ratings draft tariff language:

At this time, PG&E has no comments on the FERC 881 - Managing Transmission Line Ratings draft tariff language.

3. Please upload redlined tariff language using the "attachments” field below.

At this time, PG&E has no edits to the FERC 881 - Managing Transmission Line Ratings draft tariff language.

1. Please provide your organization's comments on the FERC 881 - Managing Transmission Line Ratings May 24 stakeholder call discussion:

Salt River Project Agricultural Improvement and Power District (SRP) requests additional information on how Western Energy Imbalance Market entities and Reliability Coordinator customers can stay engaged during the implementation phase of this initiative. The May 24 stakeholder call provided limited detail on steps that will follow the CAISO’s compliance filing.

2. Please provide a summary of your organization's comment on the FERC 881 - Managing Transmission Line Ratings draft tariff language:

No comments

3. Please upload redlined tariff language using the "attachments” field below.

No comments 

1. Please provide your organization's comments on the FERC 881 - Managing Transmission Line Ratings May 24 stakeholder call discussion:

SCE commends the CAISO for initiating this stakeholder process to address the myriad issues to implement the requirements of FERC Order 881.  SCE looks forward to coordinating with the CAISO to ensure a timely and effective implementation of Ambient Adjusted Ratings (AARs).  SCE appreciates the opportunity to comment on the CAISO’s proposals regarding implementation of FERC Order 881 and provides its responses to the issues raised during the May 24 stakeholder call as follows (SCE lists the CAISO’s request based on the corresponding slide from the May 24 CAISO presentation): 

(Slide 10) 

CAISO Request: Do stakeholders have a different view and believe modifications to the TCA are necessary 

SCE agrees there is no need to modify the TCA 

(Slide 11) 

Section 29.17 of the CAISO tariff require each WEIM Entity to submit transmission service information to the CAISO 

CAISO Request: Do stakeholders have a different view and believe changes to Section 29 of the CAISO tariff are necessary? 

SCE agrees there is no need to modify Section 29 of the CAISO tariff. 

(Slide 12) 

Section 19.5(b)(2) of the CAISO tariff requires each RC Customer to exchanging data, operating plans, operating procedures, studies, and reports with the CAISO in accordance with the Business Practice Manual for RC Services and applicable RC Operating Procedures 

CAISO Request: Do stakeholders have a different view and believe changes to Section 19 of the CAISO tariff are necessary? 

SCE agrees there are no revisions needed to Section 19 of the CAISO tariff.  

(Slide 13) 

• CAISO proposes to adapt the pro forma OATT language state that it will coordinate with participating transmission owners in their development of transmission line methodologies  
• CAISO will also coordinate with participating transmission owners on the development of exceptions and alternate ratings 
• CAISO is not proposing to create methodology requirements for participating transmission owners or WEIM Entities 

CAISO Request: Do stakeholders have a different view and believe the CAISO must create methodology requirements that apply to participating transmission owners or WEIM Entities? 

SCE strongly supports the CAISO’s position in coordinating with participating transmission owners on the development of exceptions criteria, development of alternate ratings and the development and implementation methodologies of transmission ratings for all transmission facilities as described in FERC Order 881. 

(Slide 14)  

• CAISO will propose to require submission of ambient adjusted ratings by market close to allow time for CAISO validation and market systems to utilize ratings 

CAISO Request: Do stakeholders have any perspective on the use of ambient adjusted ratings in the CAISO’s markets or the timing to incorporate ratings 

SCE is unclear of how the CAISO will use the ambient adjusted ratings (AARs) in the Day Ahead (DA) and Real-Time (RT) markets, as well as how the transmission owner will transfer this data to the CAISO.  SCE asks for further explanation on how the usage of AAR data will be operationalized in the DA and RT markets. 

• CAISO will also propose participating transmission owners validate ambient adjusted ratings prior to submission – Request: Does this proposed requirement create any stakeholder concerns 

CAISO Request: Does this proposed requirement create any stakeholder concerns 

SCE is unclear of the validation process and details of the CAISO proposal where participating transmission owners validate ambient adjusted ratings prior to submission.  SCE expects that these details will be addressed during the CAISO-led implementation discussions and activities, including further explanation and clarification on the validation requirements and guidelines.  

• CAISO will use seasonal rating if data or system issues prevent use of ambient adjusted rating 

In the absence of the required AAR data submission, SCE asks if it would be better suited to use the most recently submitted AAR ratings such as the prior day or the prior week’s data, rather than seasonal ratings. Further explanation on the use of seasonal ratings such as use cases etc. would be appreciated. 

(Slide 15)  

The CAISO proposes to use ambient adjusted ratings from the real-time market in its real-time contingency analysis 

• CAISO proposes to reflect the most granular ambient adjusted ratings used in the market as part of its RTCA during that same time interval 

CAISO Request: Do stakeholders have any perspective on which ratings to use in RTCA, or potential variance between CAISO and participant RTCAs 

SCE requests the CAISO clarify what is meant by the “most granular ambient adjusted ratings” as part of its RTCA analysis.  SCE is unclear on how this will affect the RTCA analysis and what the ratings will be used in its RTCA analysis. SCE also asks for further explanation on how the RTCA analysis will be coordinated with the Transmission Owners.  

CAISO Request: The CAISO requests stakeholder comment on the planned utilization of ambient adjusted ratings in remedial action schemes 

SCE’s position is RAS schemes should not be required to incorporate AARs in their operations. Currently, it is infeasible for SCE to implement AARs in our RAS schemes within the timeframe allocated by FERC Order 881. Moreover, the potential benefits of using AARs on RAS schemes would not justify the implementation effort.

(Slide 16)  

Seasonal ratings will apply to any long-term transmission service provided by the CAISO 

• The CAISO is holding working group meetings to foster dialogue on the development of long-term transmission products and reservations, i.e. requests for transmission service more than 10 days in the future 
• Seasonal rating methodologies would apply to these request for transmission service 

CAISO Request: Do stakeholders have any comments on how, if at all, the CAISO should address this issue in its Order No. 881 compliance filing? 

SCE’s assumption is that seasonal ratings would be used for most long-term transmission planning studies and requirements.  

(Slide 17)  

Order No. 881 requires the CAISO to implement systems and procedures necessary to allow electronic updates to ratings at least hourly 

• Ratings submitted by participating transmission owners directly into the EMS through SCADA or similar systems 
• Use of other electronic systems, such as Inter-Control Center Communication Protocol (ICCP) 

CAISO Request: Do stakeholders have any perspectives on allowing both functionalities to accommodate PTOs, EIM Entities and RC Customers? 

SCE does not have any concerns with using both functionalities to accommodate PTOs, EIM Entities and RC Customers.  However, SCE will need to ascertain the technical viability of using these methods to communicate AAR data via the ICCP Protocol and EMS / SCADA systems due to the volume of data.  SCE foresees significant technical challenges with achieving seamless data transfer using these two functionalities.  

SCE also seeks clarification on how the CAISO would accommodate other stakeholders and what these accommodations mean in terms of data communication.  

CAISO Request: Do stakeholders have perspectives on whether the CAISO should include tariff language governing dynamic line ratings, e.g. a definition and language recognizing dynamic line ratings in transmission rating methodologies? 

SCE recommends excluding tariff language governing Dynamic Line Ratings (DLRs) until the FERC NOI proceeding on DLRs has been concluded or there is ultimately a requirement to implement DLRs as part of FERC’s transmission planning and cost allocation and generator interconnection NOPR.   

(Slide 18)  

Order No. 881 requires the CAISO maintain a database of ratings and methodologies on OASIS or another password-protected website 

• Share ratings and methodologies with Transmission Providers, Market Monitor and other entities 
• Maintain database of ratings used and methodologies as well as exceptions and alternate ratings 

• Individual records of ratings in effect for each transmission line at which times 
• Maintain records for 5 years 

• CAISO proposes to limit this database to ratings and methodologies of participating transmission owners and not include EIM Entities or RC Customers 

CAISO Request: Do stakeholders have any comments on these compliance requirements the CAISO should consider? 

SCE concurs with the CAISO on the compliance requirements stated above.

2. Please provide a summary of your organization's comment on the FERC 881 - Managing Transmission Line Ratings draft tariff language:

SCE has no comment.

3. Please upload redlined tariff language using the "attachments” field below.

N/A

1. Please provide your organization's comments on the FERC 881 - Managing Transmission Line Ratings May 24 stakeholder call discussion:

The Bay Area Municipal Transmission group (BAMx)^[1] appreciates the opportunity to comment on the California Independent System Operator (CAISO) 's new initiative to comply with FERC Order No. 881 - Managing Transmission Line Ratings (DLR). BAMx's comments below address the CAISO's May 24, 2022, stakeholder call discussion.

BAMx applauds the CAISO's diligence and thoughtfulness in commencing a stakeholder process to engage stakeholders in the CAISO's effort to comply with FERC Order 881. As BAMx suggested earlier in its March 8, 2022, comment in CAISO's 2022-2023 Transmission Planning Process, BAMx believes there is a need for the CAISO to commence a stakeholder process to consider dynamic ratings to evaluate the relative benefits, costs, and challenges of DLR implementation.[2]

BAMx supports the CAISO's proposed schedule to complete its compliance filing by July 12, 2022, to use ambient-adjusted ratings (AAR). With stakeholder comments due by June 7 and the planned availability of a revised draft of CAISO tariff language by late June, the CAISO is on a good, albeit tight, schedule to comply with FERC's immediate requirements. However, BAMx recommends the CAISO start the DLR implementation discussion and activities with stakeholders as early as possible in the third quarter of 2022. As commented by stakeholders during the May 24 call, there are multiple aspects of AAR and DLR that the CAISO can implement immediately, and perhaps as early as the fourth quarter of 2022, that can vastly improve the CAISO markets, transmission planning, and operations. Furthermore, the CAISO should conduct a study to evaluate DLR implementation's relative benefits and costs that would capture the incremental benefits of early implementation.

NERC Reliability Standard FAC-008 requires each transmission owner to have a documented methodology for determining facility ratings. The CAISO is responsible for coordinating and integrating the resulting ratings in CAISO operations. FERC Order No. 881 mandates ambient-adjusted ratings (AAR) and allows transmission owners to use DLR that considers factors beyond ambient temperatures and solar heating. With technology advancements in electric transmission line monitors, BAMx encourages the CAISO to explore using both DLR and AAR with the stakeholders in the third quarter of 2022. In addition, BAMx suggests the CAISO modify its compliance tariff language to include DLR, e.g., a definition and language recognizing dynamic line ratings in CAISO transmission rating methodologies.    

BAMx appreciates the opportunity to comment on the CAISO's FERC Order 881 Compliance effort. BAMx looks forward to working with the CAISO and stakeholders in implementing DLR and AAR to further improve the CAISO markets, transmission planning, and operation.

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

[2] BAMx comments on CAISO 2022-2023 Draft Transmission Study Plan, dated March 14, 2022.

2. Please provide a summary of your organization's comment on the FERC 881 - Managing Transmission Line Ratings draft tariff language:

FERC Order No. 881 mandates the use of ambient-adjusted ratings (AAR) and allows transmission owners to use DLR that considers factors beyond ambient temperatures and solar heating. Accordingly, the CAISO should add the necessary tariff language on DLR in its compliance filing.   

3. Please upload redlined tariff language using the "attachments” field below.

BAMx has attached a redlined tariff language.