Eligible projects must interconnect with PG&E's transmission system, generally at line voltage levels greater than 60 kilovolts (kV). These projects are governed by the California Independent System Operator (CAISO) Tariff.

Process for Interconnecting

There are three paths of study that lead toward interconnection for distribution voltage projects:

Fast Track—This process is for smaller facilities of up to 5 megawatts (MW) that do not trigger the need for network upgrades to PG&E's electric system. Project proposals for applications are accepted on a rolling basis. (CAISO Appendix DD, Section 5)

Independent Study—This process is for facilities of up to 20 MW that pass the electrical independence test, which means it is electrically independent from all other projects in PG&E's study process queue. Project proposals are accepted for application on a rolling basis. (CAISO Appendix DD, Section 4)

Cluster Study—This process is for projects that are not electrically independent from all other projects in the study process queue. Customers only can apply during the cluster study window, which is during the month of March each year. (CAISO Appendix DD, Section 6) For an overview of Wholesale Transmission Generation, view the Interconnection Process Flow.

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.


Many factors need to be considered before your generating facility can be connected to the grid, including environmental requirements, land acquisition, equipment availability and permits, making the time required to complete a project highly variable. However, some deadlines and process timelines are governed by CAISO’s Generator Interconnection Procedures. For more information on CAISO study timelines, please review Sections 4, 5 and 6 of the CAISO Tariff, Appendix DD.

  • My Energy Usage
  • High-Tech Facility
  • Next Century Of Energy