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.

Interconnection generation 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.

Resource Interconnection Standards Fair 

Hosted annually, this educational forum provides stakeholders with an opportunity to learn more about the ISO’s interconnection process and recent changes affecting Cluster 15. The last fair was held Sept. 17, 2024, see the event page for presentation and video recording. 

Commercial Interest

To allocate commercial interest points to Interconnection Customers, a Load Serving Entity must do the following at least two months prior to the Cluster Application Window’s opening: 1) Provide the CAISO written, electronic notice of intent to participate in the points allocation. The notice must include (a) the publicly accessible website used by the Load Serving Entity; and (b) the contact information for the person or department Not current tariff language This document includes pending language Pending Tariff Language conducting the points allocation for the Load Serving Entity. 2) Publish on the publicly accessible website (a) the selection criteria or consideration factors for awarding points; and (b) the contact information for the person or department conducting the points allocation for the Load Serving Entity. Public websites requiring registration are permissible. Within five (5) Business Days after the deadline for Load Serving Entities to provide their notices, the CAISO will publish on the CAISO Website the contact information, website, and points allocation for each participating Load Serving Entity. 

Load Serving Entities submitting commercial interest points must do so no later than ten (10) days after the CAISO provides the list of Interconnection Requests.

Affidavits from non-Load Serving Entities must be executed by an authorized representative. The affidavit must attest the counterparty is supporting the Interconnection Request in support of corporate policy goals on sustainability; the capacity of the Interconnection Request aligns with its individual needs; the counterparty and its holding company, if any, is not affiliated with the Interconnection Customer or its holding company; and that the counterparty and its holding company and affiliates support this Interconnection Request only, and no other Interconnection Requests in this Cluster Application Window.

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. Sample reference documents are available below. Requests will only be accepted through the Grid Resource Interconnection Portal.

Grid Resource Interconnection Portal (GRIP)

The resubmission window is now closed.

View the GRIP FAQ, tutorial, and user guide.

Access the GRIP login page

Interconnection study options

The ISO has three interconnection options for resources interconnecting to the high voltage ISO controlled transmission system:

1. Cluster study process

Designed for most interconnection customers. See Pending Tariff Appendix KK Section 3.

REQUIREMENTS
APPLICATION RESUBMISSION WINDOW
  • The application Resubmission Window is open Oct 1, 2024, to Dec 2, 2024 
  • This window is only open to projects that were deemed complete in the 2023 Cluster 15 application window

2. Fast track study process

Designed for interconnection customers developing or adding less than 5 MW and is requesting Energy Only Deliverability. See Pending Tariff Appendix KK Section 5.

REQUIREMENTS

* 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 Pending Tariff Appendix KK Section 14.5.

REQUIREMENTS

Forms and resources

Interconnection study resources, supplemental examples and documents

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.

Participating transmission owner financial security instruments

Use our standardized forms to post Interconnection Financial Security with the applicable Participating Transmission Owner.

Cluster 15 Instructions for Commercial Readiness, Merchant Deposit, Study Deposit and Application Fee requirements
DCR Transmission (DCRT)
DesertLink
GridLiance West (GLW)
Horizon West Transmission (HWT)
LS Power Grid California
OC TRANSMISSION LLC
Pacific Gas and Electric Co. (PG&E)
Southern California Edison (SCE)
San Diego Gas and Electric (SDG&E)
Valley Electric Association (VEA)

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 cost guides

View all participating transmission owner per unit costs.

Generator interconnection planning process

Continue on in the generator interconnection planning process.

 

Transmission plan deliverability

Allocate or retain full or partial capacity deliverability status in a specified geographic or electrical area.

Contract development

After a resource has completed the study phase and provided the transmission plan deliverability, the customer executes the contracts, notably the generator interconnection agreement.

Queue management

After a resource has completed the study phase and provided the transmission plan deliverability, the customer executes the contracts, notably the generator interconnection agreement. 

New resource implementation

As the final step, projects need to enter and complete the New Resource Implementation process to ensure deliverables and activities needed prior to operation are complete. This will ensure successful integration into the ISO market systems and grid.

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. 

The current FERC approved Tariff sections are below.

Back to top