Interconnection Information and Map

SDG&E Transmission System Overview

The San Diego Gas & Electric’s (SDG&E) transmission system (69 kV and above) is under the operational control of the California Independent System Operator (CAISO).  Interconnection of generation facilities to the SDG&E transmission system is subject to the CAISO Federal Energy Regulatory Commission (FERC) approved Generation Interconnection Procedures (GIP) tariff.  Projects proposing to interconnect to the SDG&E transmission system (transmission lines and transmission substations) are studied in a cluster.  In order to evaluate the feasibility of an individual project, as far as transmission capacity is concerned, all projects in that cluster need to be considered to identify the available capacity. 

The transmission system included in the map on this web site provides the transmission information regarding the outlet capability from the distribution substation by indicating how the distribution substation/system is integrated into the transmission network.  This provides interconnecting customers information regarding the power flow capability from the distribution substation onto the transmission system.

For information on interconnecting to the SDG&E transmission system please refer to the following web site:

SDG&E’s transmission system, and generally the larger CAISO managed transmission grid, is configured as a network electrical system. The nature of a network transmission system is such that it requires a specific suite of studies to identify the available capacity on any transmission or substation within the network.  The networked characteristic of the transmission system serves in providing flexibility, unlike a radial system (distribution), in redistributing the power flow when an element of the network is out of service for maintenance or is forced out.

Accessing the Map

In order to view the map, you are required to register with SDG&E. Once registered, an email that contains a web link, username, password, and instructions to access and use the map will be sent to your email address.

Download Form and Register

Need Help Viewing the Map?

If you need assistance in viewing/registering for the interactive map, contact us via email or phone (858) 636-5581 during regular business hours (Mon-Fri, 7am-4pm)

Instructions to access and use the map

General Notes

  • The website is intended to provide an initial screening of generation interconnection projects. A detailed study is required to confirm all distribution upgrade costs. The interconnection customer should not rely on any cost estimates on this website as they are only intended to provide high level cost information.
  • The interactive substation area map is intended to show the general substation area and not a specific point of interconnection. The interconnection customer must meet with SDG&E to confirm the substation interconnection point.
  • The interactive feeder map is not intended for an interconnection customer to identify the exact location for interconnection. The interconnection customer must meet with SDG&E to confirm the interconnection point.
  • Feeder branch routes are not shown on the interactive map as they generally have limited capacity for interconnection. Should a branch be proposed as the point of interconnection it is likely that potentially significant distribution branch upgrades will be required to facilitate the interconnection.
  • The interactive website map is not intended for construction.
  • Interconnection to the distribution system may also impact the transmission system and will require additional analysis.
  • All interconnection requests shall follow applicable interconnection requirements.