What a 500 kV line is
SDG&E's Golden Pacific Powerlink (sometimes called the Pacific Power Link) would carry 500,000 volts on steel towers through Pauma Valley. Here is what that means, in plain terms.
The top tier of the grid
Electricity reaches your house on neighborhood lines under 34,000 volts. Lines of 34,000 to 69,000 volts carry power between nearby towns, and lines of 115,000 to 230,000 volts carry it across a region.
500,000 volts is the top tier of California's grid: lines built to move very large amounts of power over long distances.
Passing through, not serving us
The line would run about 145 miles from the Imperial Valley Substation to a new substation near San Onofre, on the Orange County line. SDG&E says it is needed to strengthen the regional grid and move power from the Imperial Valley to areas with higher demand.
Pauma Valley would be on the way, not the destination.
The state grid operator identified the need in its 2022–2023 plan. SDG&E expects to file with the CPUC, with construction as early as 2029 and the line in service by 2032.
How big it is
SDG&E's current estimate is towers 125 to 190 feet tall, 12 to 19 stories, with 1,400 to 1,800 feet between them. Other 500 kV lines in California use a strip of land about 200 feet wide reserved for the line.
Power lines and wildfire
“Since 2015 power lines have caused six of the State’s 20 most destructive wildfires.”
It has happened here. In October 2007, Cal Fire found that power lines started the Witch, Guejito and Rice fires in San Diego County. Investigators traced the Witch Fire to an SDG&E line that arced about 56 feet from where the fire began.
The Witch Fire burned 197,990 acres, killed two people and destroyed 1,650 structures.
Other effects people notice
A crackling hum
In wet weather, water drops on the wires make a crackling or humming sound near the line. It is mainly an issue on lines of 345 kV and above, like this one.
Shocks from metal
Long runs of metal near the line, such as fences, metal roofs, trellises and irrigation pipe, can pick up small electric currents. They can give annoying shocks unless the utility grounds or insulates them.
What you can do
Our neighbors at Save Temecula have a detailed explainer, too: SaveTemecula.org
Sources
- California State Auditor, Report 2021-117: Electrical System Safety (March 2022)
- CPUC decision, background on the 2007 Witch, Guejito and Rice fires
- KPBS: SDG&E, Cox power lines blamed for 2007 fires in San Diego (2008)
- NBC 7 San Diego: California's most destructive wildfires (Cal Fire figures)
- CPUC, Tri-Valley project EIR, chapter 17: Corona and induced current effects
- U.S. Department of Energy: How it works, electric transmission and distribution
- CPUC: Transmission structures fact sheet
- CPUC: Ten West Link 500 kV project description (200-foot right-of-way)
- East County Magazine: SDG&E outlines the 145-mile Golden Pacific Powerlink