Sycamore to Peñasquitos 230-kV Transmission Line

This new 15-mile electric transmission line helps improve reliability and support increasing demand for renewable energy.

Project overview

The California Public Utilities Commission (CPUC) approved the new 230-kilovolt (kV) transmission line on Oct. 13, 2016. Construction began in early 2017 to connect our existing Sycamore Canyon and Peñasquitos substations via this new electric system highway in north-central San Diego.

Key benefits

Key benefits of the Sycamore to Peñasquitos transmission line include:

  • Improved reliability for San Diego County’s 3.6 million residents.
  • Better integration of existing renewable energy resources into the power grid.
  • Safety and visual advantages of placing most of the transmission line underground.

The project helps address vital needs such as:

  • Efficiency – Delivers imported energy more efficiently to the San Diego coastal area.
  • Policy – Meets state policy goals addressing the planned retirement of coastal power plants that use once-through cooling systems.
  • Electricity demand – Reliably and economically meets the forecasted increase in electricity demand in the San Diego region.
  • Grid reliability – A statewide task force, requested by Governor Brown, deemed the project as necessary for grid reliability, due to the planned retirement of coastal power plants as well as the unanticipated early retirement of the San Onofre Nuclear Generating Station.
  • Priority – The California Independent System Operator identified this project as a priority in its 2012-2013 Transmission Plan.

Project at a glance

The project traverses approximately 15 miles of developed residential and commercial areas as well as undeveloped areas in north-central San Diego. Components include:

Segment A

  • Approximately 0.75 miles of new 230-kV transmission line and relocated 138-kV power line located underground and on new steel poles and steel H-frame structures all within SDG&E’s existing right-of-way located between the Sycamore Canyon Substation and a trail starting at Stonebridge Parkway.

Segment B

  • Approximately 11.5 miles of 230-kV underground transmis­sion line within existing roads and bridges.

Segment C

  • A new cable pole at the transition point from underground to overhead near the intersection of Scranton Road and Carroll Canyon Road and approximately 2.2 miles of new 230-kV transmission line and communication cable on existing 230-kV tubular steel poles within SDG&E’s existing right-of-way from the cable pole to the Peñasquitos Substation.