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​2018-2019 transmission planning process

The California ISO 2018-2019 transmission planning cycle involves key stakeholder activities from 2018 through early 2019. 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.


Process status

Phase 3: In progress
Board of Governors approval of transmission plan: March 27, 2018
Phase 1:  March 30, 2018 Final Study Plan

Board approved plan

Current meeting

Market notices

Phase 3 - select project sponsor

Project sponsors submit proposals for transmission solutions that are eligible for competitive solicitation and were approved by the ISO Board in the comprehensive transmission plan at the end of phase 2.

Phase 2 - conduct technical studies and develop comprehensive plan

The ISO performs technical studies, and with stakeholders develops an annual comprehensive transmission plan that examines the ISO controlled grid and reliability requirements and identifies mitigation solutions. Transmission mitigation solutions may meet reliability, economic or public policy-driven needs that support state, federal, municipal and county policy requirements and directives.

Transmission plan

  • 2018-2019 transmission planning process - transmission plan
    • 2018-2019 transmission planning process - board approved plan and appendices
      Minor updates to executive summary. Appendix B is available on the Market Participant Portal
    • 2018-2019 transmission planning process - revised draft plan and appendices
      Appendix B is available on Market Participant Portal
    • 2018-2019 transmission planning process - draft plan and appendices
      Appendix B is available on the Market Participant Portal
    • Meeting Feb 14, 2019

Reliability assessment

Special studies 

Policy-driven and economic assessment

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.