The California ISO 2026-2027 transmission planning cycle involves key stakeholder activities from 2026 through early 2027. 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 15, 2026 Final study plan posted
Aug 14, 2026 Preliminary reliability study results and mitigation solutions posted Aug 28, 2026* Post scenario base cases Sep 23, 2026* Meeting (day 1) Sep 24, 2026* Meeting (day 2) Oct 08, 2026* Comments due Oct 30, 2026* Final reliability study results posting Nov 16, 2026* Preliminary assessment of policy and economic planning studies posting Nov 18, 2026* Meeting Dec 04, 2026* Comments due Dec 07, 2026* Meeting, Long-term LCR Dec 21, 2026* Comments due Mar 31, 2027* Draft transmission plan posting Apr 07, 2027* Meeting May 2027* Board of Governors meeting May 31, 2027* Final board-approved transmission plan posting |