FERC Order No. 881 - Managing Transmission Line Ratings: Draft tariff revisions posted, call on 12/16/24

The California ISO has posted additional draft tariff revisions for its implementation of FERC Order No. 881, and will hold a virtual stakeholder call on Dec. 16, 2024.

The ISO plans to submit these tariff revisions to the Federal Energy Regulatory Commission (FERC) as part of a supplemental compliance filing with Order No. 881. As part of that supplemental compliance filing, the ISO plans to request authority to modify the effective date for the ISO’s Order No. 881 tariff provisions to a date no later than Dec. 1, 2026, subject to providing FERC with notice of the actual effective date 5 days before the tariff revisions will become effective. 

As discussed in the context of the ISO’s Order No. 881 stakeholder process, the ISO intends to deploy functionality in 2025 to accept hourly ratings through its Energy Management System via Inter-Control Center Communications Protocol. In 2025, the ISO also plans to deploy functionality through Open Access Technology International's(OATI) webLineR platform that will allow transmission providers and transmission operators to provide the ISO with hourly ambient adjusted ratings, seasonal ratings and emergency ratings. The ISO intends to monitor the submission of these ratings and evaluate the performance of the webLineR platform. The ISO plans to deploy and test functionality to incorporate ratings from WebLineR into its day-ahead and real-time market systems with a target go-live date in April of 2026. Based on stakeholder input and FERC authorization, the ISO may target a go-live date to incorporate ratings from WebLineR into its real-time market systems in Q1 2026.

The ISO will also undertake additional work to address the intersection of nomograms and hourly ambient adjusted ratings, as well as how to incorporate hourly ambient adjusted ratings into remedial action schemes, total transfer capability, available transfer capability, and scheduling limits. The ISO plans to complete this additional work by fall of 2026. 

The draft tariff language and associated materials are available on the FERC Order No. 881 - Managing Transmission Line Ratings Phase 2 initiative webpage.

The call will be recorded and the video file posted on the initiative webpage for a limited time. The recording is for informational convenience purposes only, and any related transcriptions should not be reprinted without the ISO’s permission.

Please submit comments on the draft tariff revisions as well as the ISO’s plans to request a new effective date for its Order No. 881 tariff language by end of day Dec. 12, 2024, through the ISO’s commenting tool using the link on the initiative webpage.

Meeting details

Date: Dec. 16, 2024

Time: 10: 30 a.m. - 11:30 a.m. Pacific Time

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Participation information

Step 1: join web conference

Step 2: connect audio by selecting computer audio or selecting call me and enter your phone number

Audio only participation: call 1-844-621-3956, access code: 24970475394.