The California ISO 2025-2026 transmission planning cycle involves key stakeholder activities from 2025 through early 2026. 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 |
|---|---|---|---|
|
Jun 03, 2025 Final study plan posted
Aug 15, 2025 Preliminary reliability study results and mitigation solutions posted Aug 30, 2025* Scenario base cases posting Sep 24-25, 2025* Hybrid stakeholder meeting Oct 09, 2025* Comments due Oct 31, 2025* Final reliability study results posting Nov 2025* Preliminary assessment of policy & economic planning studies posting Nov 19, 2025* Hybrid stakeholder meeting Dec 05, 2025* Comments due Mar 31, 2026* Draft transmission plan posting Apr 15, 2026* Meeting May 2026* Board of Governors meeting May 2026* Board-approved transmission plan posting |