Wholesale Transmission Generation: 60 kV and Above

Interconnecting Your Generating Facility with PG&E's Transmission System

If you are interested in selling power directly through the California Independent System Operator (CAISO) network and you want to apply to connect to a PG&E transmission line of 60 kV or greater, this page is for you.

CAISO is the non-profit, public-benefit corporation that operates most of the high-voltage wholesale power grid in California, including the transmission lines in PG&E's service territory. During some parts of the interconnection process, CAISO plays a leading role, and during others, PG&E takes the lead. This page explains the respective roles and provides information about project siting, costs and timelines.

View the Wholesale Transmission Interconnection Process Slides to learn more >> Process Overview, Cluster Study, Independent Study and Fast Track.

CAISO's Role

Your first step in applying to interconnect with PG&E's transmission system is through CAISO. CAISO oversees the application process for generating facilities that apply as part of a Cluster Study, an Independent Study or a Fast Track process. CAISO conducts initial studies on the effects the proposed generation facilities will have on the transmission grid and also ensures the fair and consistent treatment of all applicants.

View more information, including definitions of the different processes, on CAISO's website >>

PG&E's Role

All owner/generators who wish to connect their systems to the PG&E electric transmission grid must have an interconnection agreement with PG&E and CAISO. Once CAISO's studies are completed, your interconnection agreement can be finalized and the necessary interconnection facilities and network upgrades required for the physical interconnection between your generating facility and our transmission system can be built.

Your Project Site

To help you evaluate the sites you are considering, PG&E has created a map that shows the locations of selected electric transmission and distribution lines, associated substations and their names, operating voltages, and line capacity. If your project is in the planning stages, you'll want to check out this map. View the map >>

Before you get started on your project, please contact your local city or county building or planning department to learn about permitting requirements.

Find your local building department >>

Understanding Costs

In addition to the costs associated with designing and installing your generation facility, you will be required to pay for interconnecting your generating system to the PG&E electric transmission system. This cost will depend on several factors, including your generation system's size, substation and circuit capability and voltage. Interconnection costs can vary significantly, depending on the interconnection point and size of the generation project.

View information about 2012 Transmission Owner Unit Costs >>


Many factors need to be considered before a customer can be connected to the grid, including environmental requirements, land acquisition, equipment availability and permits, so the time required to complete a project is highly variable. However, some deadlines and process timelines are governed by CAISO's Generator Interconnection Procedures.

The CAISO Tariff mandates that a commercial operation date cannot exceed seven years from the date on the interconnection application unless the developer, the Participating Transmission Owner (PG&E) and CAISO agree to delay the interconnection beyond seven years through a Material Modification Request the developer submits to CAISO.

PG&E is Here to Help

If you have questions about the transmission interconnection process and its rules, PG&E is here to help. Our Generation Interconnection Services team can help you ensure a successful project and a safe, reliable interconnection to the grid. For assistance, please email wholesalegen@pge.com.

You can also contact CAISO at 916-351-4400 or visit the CAISO website.

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