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.
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Oct 31, 2025 Final reliability study results posted
Mar 31, 2026 Draft transmission plan posting Apr 07, 2026 Hybrid meeting April 21, 2026 Comments due May 2026* Board of Governors meeting May 2026* Board-approved transmission plan posting |
Web meeting |
https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-2025-2026-Transmission-planning-process-policy-and-Economic-Preliminary-Assessment-and-Study-updates-Nov-19-25.pdf | View comments |
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Final Reliability Assessment Results
VEA - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
SDG&E - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
SCE - TEHBC - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
SCE - NOL - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
SCE - MAIN - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
SCE - EASTERN - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E - NVLY - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E -NCNB - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E - KERN - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E - Humbolt - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E - High Voltage - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E - GFA - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E - GBA - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E - CVLY - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
PG&E - CCLP - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
Bulk - South - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
Bulk - North - 2025-2026 Transmission Planning Process Final Reliability Assessment Results 10/31/2025
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Web meeting |
https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-2025-2026-TransmissionPlanningProcess-Sep2525.pdf
Presentation - 2025-2026 Transmission Planning Process - Sep 25, 2025 09/22/2025
Presentation - San Diego General Electric - 2025-2026 Transmission Planning Process - Sep 25, 2025 09/22/2025
Presentation - Southern California Edison - 2025-2026 Transmission Planning Process - Sep 25, 2025 09/22/2025
Presentation - GridLiance West - 2025-2026 Transmission Planning Process - Sep 25, 2025 09/22/2025
Presentation - PG&E - 2025-2026 Transmission Planning Process - Sep 25, 2025 09/23/2025
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Web meeting |
https://stakeholdercenter.caiso.com/InitiativeDocuments/Agenda-2025-2026-Transmission-Planning-Process-Sep-24-2025.pdf.pdf
Agenda - 2025-2026 Transmission Planning Process - Sep 24, 2025 09/22/2025
Presentation- 2025-2026 Transmission Planning Process - Sep 24, 2025 09/22/2025
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https://www.caiso.com/generation-transmission/transmission/transmission-planning#planning-engagement
2025-2026 Request Window (Closes Oct 15, 2025) 08/15/2025
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Preliminary Reliability Assessment Results https://stakeholdercenter.caiso.com/InitiativeDocuments/BULK-NORTH-2025-2026-Transmission-Planning-Process-Preliminary-Reliability-Assessment-Results.pdf
BULK NORTH 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
BULK SOUTH 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E CCLP 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E CVLY 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E FRESNO 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E GBA 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E High Voltage 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E HUMB 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E KERN 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E NCNB 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
PG&E NVLY 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
SCE EASTERN 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
SCE MAIN 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
SCE NOL 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
SCE TEHBC 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
SDG&E 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
VEA 2025-2026 Transmission Planning Process Preliminary Reliability Assessment Results 08/15/2025
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https://stakeholdercenter.caiso.com/InitiativeDocuments/2025-2026TransmissionPlanningProcessUnifiedPlanningAssumptionsAndStudyPlan.pdf
2025-2026 Transmission Planning Process Unified Planning Assumptions and Study Plan 06/03/2025
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Web meeting |
https://stakeholdercenter.caiso.com/InitiativeDocuments/SCE-Load-Allocation-for-Local-Area-Studies-2025-2026-TPP.pdf
https://stakeholdercenter.caiso.com/InitiativeDocuments/PGE-Transmission-Planning-Load-Forecast-2025.pdf
https://stakeholdercenter.caiso.com/InitiativeDocuments/2025-2026-TPP-SHMeeting1-DraftStudyPlan.pdf
Presentation - 2025-2026 Transmission Planning Process- Draft Study Plan - Feb 26, 2025 02/24/2025
Presentation - SDGE - Methodologies to Derive Bus Level Forecast - Feb 26, 2025 02/26/2025
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https://stakeholdercenter.caiso.com/InitiativeDocuments/2025-2026-Transmission-Planning-Process-Unified-Planning-Assumptions-and-Draft-Study-Plan.pdf
2025-2026 Transmission Planning Process Unified Planning Assumptions and Draft Study Plan 02/19/2025
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Stakeholder comment period for 2025-2026 unified planning assumptions and study plan is Dec 30, 2024 through Jan 30, 2025. See the notice for more information. https://www.caiso.com/notices/stakeholder-input-for-2025-2026-unified-planning-assumptions
Link to Dec 30 notice 12/30/2024
Letter - Data Request and Invitation to 2025-2026 Transmission Planning Process - Dec 30, 2024 12/30/2024
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