SDG&E to Build, Own and Operate New 500-kV Transmission Line in Southern California

San Diego Gas & Electric Company (SDG&E) will build, own and operate a new 500-kV transmission line between the existing Imperial Valley Substation and the border of San Diego and Orange Counties.

According to the California Independent System Operator (CAISO), the project is essential for California to achieve its carbon reduction goals and the resilience and modernization of the electrical grid in Southern California by offering a new pathway in a currently constrained area. Increasing transmission capacity across the region will help reduce unnecessary costs of congestion, integrate more clean energy, and expand access to resources in the Imperial Valley and the Southwest.

The transmission pathway was recognized in CAISO’s 2022-2023 Transmission Plan, which identified the need for 45 transmission projects throughout the state, including this project.

Costs to build and upgrade high-voltage transmission lines (200kV or higher) providing statewide benefits are proportionately distributed among all California customers within CAISO’s Balancing Authority Area and governed by the Federal Regulatory Energy Commission. The costs of building transmission projects are shared across California to limit the estimated cost impact on SDG&E customers to approximately 9%, based on current data.

SDG&E will also integrate its wildfire safety program into the project. The initiative has helped prevent a utility-caused wildfire for nearly 18 years, highlighting SDG&E’s commitment to safety and resilience.

SDG&E will start a community engagement process where the public will have multiple opportunities to submit feedback on ways to ensure the project is built responsibly as part of the state and federal permitting process. While construction on the transmission line is expected to begin in 2029, a target in-service date is scheduled for 2032, depending on necessary state and federal agency approvals and permits.