Transmission planning
Transmission planning at the ISO actively engages stakeholder and public input and uses the best engineering analysis possible to determine short- and long-term infrastructure needs.
Transmission plans
The annual transmission plan serves as the formal and Board-approved roadmap for infrastructure requirements for the ISO balancing authority. ISO and participating transmission owner studies demonstrate how the ISO is planning for infrastructure needs while meeting North American Electric Reliability Corporation and ISO planning standards.
Current plan
- ISO Board Approved 2023-2024 Transmission Plan05/31/2024, 11:28 AM
- Appendix A - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
- Appendix B - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
- Appendix C - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
- Appendix D - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
- Appendix E - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
- Appendix F - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
- Appendix G - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
- Appendix H - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
- Appendix I - Board Approved 2023-2024 - Transmission Plan05/31/2024, 11:28 AM
Plans under development
- 2024-2025 Transmission Planning Process05/18/2024, 7:42 PM
- 20-Year transmission outlook (2023-2024)05/18/2024, 7:42 PM
- 2024 20 Year Transmission Outlook Jul 31, 202407/31/2024, 3:44 PM
- 2023-2024 Transmission Planning Process05/18/2024, 7:41 PM
Standards and processes
The Transmission Planning Standards assure consistent reliability standards across the ISO controlled grid, above those established by NERC and WECC that will maintain or improve transmission system reliability to a level appropriate for the California system and will ensure secure and reliable operation of the ISO controlled grid. View the previous planning standards and processes.
- CIP-014-2 R2 Risk Assessment Review and Verification Methodology v2.009/09/2024, 1:50 PM
- Transmission Planning Process Overview10/30/2023, 10:33 AM
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FAC-002-4-R6 Qualified Change Technical Bulletin10/24/2023, 2:17 PM
Definition of qualified change in compliance with FAC-002-4 R6 Facility Interconnection Studies.
- ISO Planning Standards - Effective Feb 2, 202302/14/2023, 8:02 AM
- FAC-10-3 and FAC-14-2 System Operating Limits Methodology for the Planning Horizon v3.409/27/2022, 1:24 PM
- FAC-013-2 Transfer Capability Methodology Near-Term Transmission Planning Horizon08/04/2020, 9:31 AM
- Transmission Economic Assessment Methodology - Nov 2, 201711/17/2017, 4:00 PM
ISO, CEC and CPUC
Memorandum of Understanding
The Memorandum of Understanding (MOU) is an agreement between The California Public Utilities Commission (CPUC), The California Energy Commission (CEC), and the ISO. The MOU tightens the linkages between resource and transmission planning activities, interconnection processes and resource procurement so California is better equipped to meet its reliability needs and clean-energy policy objectives required by Senate Bill 100.
- ISO CEC and CPUC Memorandum of Understanding - Dec 202201/19/2023, 10:00 AM
Transmission planning engagement
Request window
During a two-month period in Phase 2 of the Transmission Planning Process, parties may submit potential mitigation solutions, either transmission or non-transmission alternatives, to address reliability constraints identified in the current planning cycle.
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Request Window Submission Form and Attachment A05/14/2015, 1:24 PM
Form used in Phase 2 during the two-month Request Window to submit potential mitigation solutions, either transmission or non-transmission alternatives, to address reliability constraints identified in the current planning cycle.
Competitive solicitation process
Project sponsor
To become a project sponsor, submit a proposal, the application form, and workbook for the Transmission Planning Process phase 3 competitive solicitation process. More information about this process is available in the application.
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Prior Projects and Experience Workbook06/26/2024, 10:56 AM
Workbook for competitive solicitation projects.
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Competitive Solicitation Transmission Project Sponsor Application06/26/2024, 10:55 AM
Application used to submit proposals to build and own the approved projects that are eligible for competitive solicitation.
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2023-2024 Competitive Solicitation Questions Matrix06/26/2024, 10:55 AM
Questions and answers for 2023-2024 competitive solicitation projects.
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Cost and Cost Containment Workbook (Revised)06/26/2024, 10:55 AM
Workbook for competitive solicitation projects.
Approved project sponsor
Once selected as an approved project sponsor, a construction plan is needed. Use the construction status report template for the initial construction plan and the subsequent construction plan status reports in accordance with Section 24.6 of the California ISO Tariff.
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Construction Report Template - Approved Project Sponsor Agreement (APSA) Construction Status09/14/2018, 12:03 PM
This is the construction status report template to be used by Approved Project Sponsors for the initial construction plan and the subsequent construction plan status reports in accordance with Section 24.6 of the California ISO Tariff.
Submittal requirements - data for power system modeling and analysis
Project sponsors use these documents when submitting proposals for the competitive solicitation process.
North American Electric Reliability Corporation (NERC) - MOD-32-1
Documentation regarding base case development and data submittal requirements for transmission and generation owners in accordance with NERC Reliability Standard MOD-032-1
- ISO-DCRT MOD-032-1 Requirements10/24/2024, 8:24 AM
- ISO-SDGE MOD-032-1 Requirements10/10/2024, 11:23 AM
- ISO-HWT MOD-032-1 Requirements10/10/2024, 11:23 AM
- ISO-VEA MOD-032-1 Requirements09/09/2024, 8:48 AM
- ISO-PG&E MOD-032-1 Requirements02/15/2024, 2:52 PM
- ISO-SCE MOD-032-1 Requirements09/19/2023, 2:25 PM
- ISO-DWR MOD-032-1 Requirements12/13/2021, 10:36 AM
- ISO-DesertLink MOD-032-1 Requirements04/16/2020, 8:35 AM
- ISO City of Pasadena MOD032-1 Requirements09/27/2018, 3:33 PM
- ISO-SVP MOD-032-1 Requirements08/28/2018, 10:59 AM
- ISO-TBC MOD-032-1 Requirements07/19/2018, 1:12 PM
- ISO-MWD MOD-032-1 Requirements10/03/2017, 4:08 PM
- ISO-HHWP MOD-032-1 Requirements06/05/2017, 11:11 AM
Submittal requirements - transmission planning process (TPP) BPM
Data templates, resource list, and documentation regarding base case development and data submittal requirements for participating generator owners in accordance with ISO’s Transmission Planning Process Business Practice Manual (BPM).
- Video - Generator Model Data Requirements Update - Jan 14, 2020
- Video - Generator Model Data Requirements Webinar - May 30, 2019
- Resource Category and Phase All Participating Resource IDs05/14/2024, 8:32 AM
- Data Template for Generators in Category 1 and 205/09/2024, 11:49 AM
- Data Template for Generators in Category 503/25/2024, 11:23 AM
- Data Template for Generators in Category 3 and 403/25/2024, 11:23 AM
- Presentation - Electromagnetic Transient Model Submission Requirements - Apr 28, 202104/23/2021, 11:58 AM
- California ISO Electromagnetic Transient Modeling Requirements04/19/2021, 2:15 PM
- Presentation - Electromagnetic Transient Model Submission Requirements - Oct 21, 202010/16/2020, 9:08 AM
Accessing transmission data
Transmission planning base case data
The ISO provides access to its regional transmission planning base case data and dynamic data files to members of the Western Electricity Coordinating Council (WECC) and non-WECC members who have an approved WECC Base Case Data Request Package prior to requesting access to this data. Requesting entities must submit a Regional Transmission Non-Disclosure Agreement (NDA). Please review the Submission Instructions before submitting any forms for thorough instructions and links to the necessary forms.
Accessing positive sequence load flow data and dynamic models descriptions
General Electric International, Inc. (GEII) is the only party authorized to distribute GE Positive Sequence Load Flow (PSLF) reference manuals to other parties. A non-PSLF licensed user wanting copies of the load flow data and dynamic models export/import documents needs to contact GEII.
Please direct all questions and access requests for a PSLF license to GEII at pslf-caiso@ge.com.
Planning coordinator services
A Planning Coordinator coordinates and integrates transmission facility and service plans, resource plans, and protection system plans among the Transmission Planner(s), Resource Planner(s), and Distribution Provider(s) within its area of purview. As a Planning Coordinator, the ISO provides the Planning Coordinator functions set forth in the Reliability Standards to NERC registered Transmission Planners, Resource Planners, and Distribution Providers that are connected to the transmission network under ISO operational control.
- Template - ISO Planning Coordinator Agreement11/25/2020, 1:24 PM
- Technical Bulletin - California ISO Planning Coordinator Definition ver 1.0403/16/2020, 4:27 PM
- Generic Schedule for Implementing a Planning Services Agreement with an Adjacent System12/10/2015, 11:41 AM
Transmission access charge (TAC) forecast model
This model is used to project TAC impact of the capital program in each year’s transmission plan.
Information provided for CPUC integrated resource plan
See information on transmission capability estimate inputs for CPUC integrated resource planning.
- Transmission capability estimate inputs for CPUC integrated resource plan - Aug 29, 2024
- Transmission capability estimate inputs for CPUC integrated resource plan - Jul 05, 2023
- Transmission capability estimate inputs for CPUC integrated resource plan - Jul 27, 2021
- Transmission capability estimate inputs for CPUC integrated resource plan - May 28, 2019
Related ISO Tariff and Business Practice Manual
- ISO Tariff05/18/2024, 7:42 PM
- ISO Tariff Section 2404/05/2024, 7:42 PM
- Business Practice Manual for Transmission Planning Process05/16/2024, 3:29 AM