Interconnection request and study
New resources interested in interconnecting to the ISO controlled grid are required to complete a study process. To begin the study process, resources must submit an Interconnection Request into a tariff-defined study process.
Transmission-level resource interconnection
In general, if the desired interconnection voltage level is listed below, an Interconnection Request should be filed with the ISO. Review the Interconnection Area Substation Point of Interconnection (POI) List to determine if the desired POI is ISO controlled. Contact IRInfo@caiso.com for additional assistance.
- Pacific Gas & Electric service area: transmission lines 60 kV and higher
- Southern California Edison service area: several 66 kV and 115 kV lines and all transmission lines 220 kV and 500 kV
- San Diego Gas & Electric service area: transmission lines 69 kV and higher
- Municipal utility service areas: some lines owned by the municipal utilities but outside of the cities’ boundaries
- Valley Electric Association service area: transmission lines 138 kV
- GridLiance West service area: transmission lines 230 kV and 500 kV
- Ten West Link Delaney to Colorado River (DCRT): 500 kV transmission line
- DesertLink Harry Allen to Eldorado (DSLK): 500 kV transmission line
- Other transmission lines: Trans-Elect NTD Path 15, Startrans, Trans Bay Cable, Western Area Power Administration-Path 15, and several lines outside the ISO Balancing Authority which have been turned over to ISO for operational control
Informational presentations and guidelines
The generator interconnection planning process provides a pathway for power plants to interconnect to the ISO controlled grid. We provide information and resources to help you understand and comply with requirements.
Learn about the many facets of interconnection application—from how to apply, the requirements, and what to anticipate during the process.
Generator Interconnection Deliverability Allocation Procedures Customer Guidelines
Save the Date - Resource Interconnection Standards Fair on 9/17/24 | California ISO (caiso.com)
To confirm which interconnection study is appropriate, check with the utility that serves the territory where the project is located.
Submit an interconnection request for study
Determine which available study process is appropriate for your interconnecting facility then submit an interconnection request to begin the study. Interconnection requests are submitted electronically, including the interconnection request document below, through the ISO Resource Interconnection Management System (RIMS) application.
To submit a new interconnection request or update an existing interconnection request, use the Interconnection Request (Appendix 1) Microsoft Word template and the Generating Facility Data (Attachment A to Appendix 1) Microsoft Excel spreadsheet – both documents are required. Sample completed templates for both document types are available for reference.
Interconnection study options
The ISO has four interconnection options for resources interconnecting to the high voltage ISO controlled transmission system:
1. Cluster study process
Designed for most interconnection customers. See Tariff Appendix DD Section 3.
REQUIREMENTS
- Completed interconnection request
- Study deposit
- Evidence of site exclusivity (or deposit in lieu of)
- Technical data
REQUEST WINDOW
- Request window is open once per year: April 1 - April 15 or the following business day.
- All projects in a cluster are assigned a queue position number and have equal standing within the cluster.
2. Fast track study process
Designed for interconnection customers developing or adding less than 5 MW and is requesting Energy Only Deliverability. See Tariff Appendix DD Section 5.
REQUIREMENTS
- No larger than 5 MW
- Energy Only Deliverability status
- Must pass all screens*, as detailed in Tariff Appendix DD Section 5.2.1
- Completed interconnection request
- Non-Refundable $500 processing fee
- Evidence of site exclusivity
- Technical data
* Customer Options meetings are needed if they fail screens. Additional supplemental review meeting based on the outcomes of the customer options meetings (includes a short study process and additional deposit for estimated costs).
REQUEST WINDOW
- An applicant may apply at any time of the year
3. ISO as an affected system study
Designed for interconnection customer in Balancing Authority Areas that may affect the reliability of the ISO Controlled Grid. See Tariff Appendix DD Section 14.5.
REQUIREMENTS
Forms and resources
Interconnection study resources, supplemental examples and documents
- Appendix B to Generator Interconnection Study Process Agreement09/30/2022, 3:23 PM
- Briefing on Resources Available for Near Term Interconnection12/05/2023, 3:03 PM
- Evaluation of Generator Reactive Capability - White Paper09/02/2021, 11:26 AM
- Generating Facility Data - Sample Solar and Battery
- Generating Facility Data - Sample Wind
- Generator Interconnection Deliverability Allocation Procedures Customer Guidelines09/28/2023, 9:06 AM
- Inverter-Based Interconnection Requests (IBR) Dynamic Model Review Guideline10/07/2021, 10:10 AM
- ISO Inverter-Based Model Validation Procedure03/30/2023, 9:17 AM
- Pre-Application Report Request Form11/09/2016, 12:56 PM
- Prohibited Project Names03/13/2023, 12:02 PM
- Upgrade and Cost Responsibility Implementation11/27/2019, 9:50 AM
Affected systems
The ISO will notify the Affected System Operators that are potentially affected by the Interconnection Customer’s Interconnection Request. If required by an Identified Affected System, the Interconnection Customer will sign separate study agreements with the Identified Affected System and pay for necessary studies. See Tariff Appendix DD, section 3.7.
- Affected Systems Contact List11/02/2023, 9:40 AM
Participating transmission owner financial security instruments
Use our standardized forms to post Interconnection Financial Security with the applicable Participating Transmission Owner.
DCR Transmission (DCRT)
- Letter of Credit - DCRT04/05/2018, 8:46 AM
GridLiance West (GLW)
- Letter of Credit - GLW10/03/2022, 8:44 AM
Pacific Gas and Electric Co. (PG&E)
- Surety Bond - PG&E Interconnection Facilities06/04/2024, 2:02 PM
- Surety Bond - PG&E Network Upgrades05/21/2024, 3:28 PM
- Letter of Credit - PG&E05/21/2024, 3:28 PM
- PG&E Escrow Agreement - Transmission Tariff05/21/2024, 3:28 PM
- Letter of Credit - PG&E04/01/2019, 10:16 AM
- Escrow Agreement - PG&E03/26/2019, 11:34 AM
- Surety Bond - PG&E03/01/2016, 9:57 AM
Southern California Edison (SCE)
- Letter of Credit - SCE01/10/2024, 8:24 AM
- Surety Bond - SCE03/21/2023, 10:51 AM
- Escrow Agreement - SCE12/16/2022, 9:38 AM
- Guaranty - SCE02/02/2016, 9:03 AM
San Diego Gas and Electric (SDGE)
- Guaranty - SDG&E06/04/2024, 2:02 PM
- Escrow Agreement - SDG&E06/04/2024, 2:02 PM
- Letter of Credit - SDG&E06/04/2024, 2:01 PM
- Surety Bond - SDGE05/24/2024, 4:29 PM
- Letter of Credit - SDG&E04/01/2021, 1:44 PM
- Surety Bond - SDG&E03/24/2021, 9:02 AM
- Guaranty - SDG&E03/23/2021, 8:57 AM
Valley Electric Association (VEA)
- Letter of Credit - VEA04/17/2013, 3:17 PM
- Surety Bond - VEA04/17/2013, 2:41 PM
Participating transmission owner per unit costs
Learn the anticipated costs of procuring and installing facilities required to interconnect generation to the applicable Participating Transmission Owner.
- Current Emergency Interconnection Network Upgrade Maximum08/10/2023, 1:11 PM
- Current Reliability Network Upgrade Reimbursement Maximum08/08/2023, 3:00 PM
Current cost guides
- SCE 2023 FInal Per Unit Cost Guide09/18/2023, 10:49 AM
- VEA 2023 Final Per Unit Cost Guide09/18/2023, 10:49 AM
- DSLK 2023 Final Per Unit Cost Guide09/18/2023, 10:49 AM
- GLW 2023 Final Per Unit Cost Guide09/18/2023, 10:49 AM
- PGAE 2023 Final Per Unit Cost Guide09/18/2023, 10:49 AM
- SDGE 2023 Final Per Unit Cost Guide09/18/2023, 10:49 AM
- DCRT 2023 Final Per Unit Cost Guide09/18/2023, 10:49 AM
Generator interconnection planning process
Continue on in the generator interconnection planning process.
Related ISO Tariff and Business Practice Manuals
The California ISO operates under the terms and conditions of its FERC-approved tariff. Business practice manuals provide detailed rules, procedures and examples for the administration, operation, planning and accounting requirements of the ISO and the market that are consistent with the ISO tariff.
The ISO has filed Tariff Amendments to Comply with Order No. 2023. The documentation below contains draft language pending FERC approval.
- FERC Order 2023 Pending ISO Tariff Appendix A
- FERC Order 2023 Pending ISO Tariff Appendix DD
- FERC Order 2023 Pending ISO Tariff Appendix KK
- FERC Order 2023 Pending ISO Tariff Appendix LL
- FERC Order 2023 Pending ISO Tariff Appendix MM
- FERC Order 2023 Pending ISO Tariff Section 25
The current FERC approved Tariff sections are below.
- ISO Tariff05/18/2024, 7:42 PM
- ISO Tariff, Section 2504/05/2024, 11:14 AM
- ISO Tariff, Appendix DD - Generator Interconnection Deliverability Allocation Procedures (GIDAP)04/05/2024, 11:14 AM
- Business Practice Manual for Generator Interconnection and Deliverability Allocation Procedures05/16/2024, 3:29 AM
- Business Practice Manual for Generator Interconnection Procedures05/16/2024, 3:29 AM
- Business Practice Manual for Generator Management05/16/2024, 3:29 AM
- Business Practice Manual for Transmission Planning Process05/16/2024, 3:29 AM
- Business Practice Manual for Distributed Generation for Deliverability05/16/2024, 3:29 AM