2024-2025 Transmission planning process

Started: Dec 28, 2023

Jeff Billinton

The California ISO 2024-2025 transmission planning cycle involves key stakeholder activities from 2024 through early 2025. Each year, the ISO conducts its transmission planning process to identify potential system limitations as well as opportunities for system reinforcements that improve reliability and efficiency. The transmission planning process core product is the ISO Transmission Plan, which provides an evaluation of the ISO control grid, examines conventional grid reliability requirements and projects, summarizes key collaborative activities and provides details on key study areas and associated findings.


Development Decision Implementation Completed/Closed
Feb 22, 2024 Draft study plan posted
April 2024* Final study plan posting
Aug 15, 2024* Preliminary reliability study results and mitigation solutions posting
Aug 30, 2024* Base scenario base case posting
Sep 25-26, 2024* Meeting
Oct 10, 2024* Comments due
Oct 31, 2024* Final reliability study results posting
Nov 12, 2024* Preliminary assessment of policy and economic studies posting
Nov 14, 2024* Meeting
Dec 02, 2024* Comments due
Mar 31, 2025* Draft transmission plan posting
Apr 15, 2025* Meeting
May 2025* Board of governors meeting
May 30, 2025* Final board-approved transmission plan posting


Web meeting

Presentation - 2024-2025 Transmission Planning Process - Feb 28, 2024

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Phase 1 - develop study plan

In collaboration with stakeholders, the ISO develops and finalizes a study plan that consists of a common set of assumptions for reliability and other planning studies the ISO will perform in Phase 2. The development of a conceptual statewide transmission plan begins in this phase and may be completed during Phase 1 or Phase 2. Stakeholders may also request economic planning studies to assess potential economic benefits (such as congestion relief) in specific areas of the grid.

Draft Study Plan - 2024-2025 Transmission Planning Process

Stakeholder comment period for 2024-2025 unified planning assumptions and study plan is Dec 28, 2023 through Jan 29, 2024. See the notice for more information.

Letter - Data Request and Invitation to the CAISO 2024-2025 Transmission Planning Process - Dec 28, 2023