REGION — Plans for a new high-voltage transmission system bridging the power supply from the Arizona border to Los Angeles have some North County residents concerned that a massive power line will cut directly through the heart of Palomar Mountain and its nearby unincorporated community.
Last May, the California Independent System Operator, an independent nonprofit responsible for maintaining the reliability of the electric grid and operating the wholesale energy market in California and a portion of Nevada, identified a list of projects in its 2022-2023 Transmission Plan.
The plan, developed in coordination with the California Public Utilities Commission and the California Energy Commission, identified 45 projects for system expansion and upgrades necessary to meet the region’s growing energy demand and transition to a carbon-free electric grid.
The CAISO board recently approved the transmission plan, which features upgrades to existing power line segments along the Interstate 10 corridor and the installation of new transmission lines, including an approximately 137-mile, 500-kV (500,000 volts) line spanning portions of Imperial, San Diego, Riverside and Orange counties.
The proposed Imperial Valley-North of SONGS line system would connect an existing Imperial Valley substation to a new proposed 500/230-kV substation located north of the decommissioned San Onofre Nuclear Generating Station.
Horizon West Transmission, the company developing portions of the project, would also construct the new substation as part of the project.
According to Horizon West, the proposed transmission line would provide a critical link between renewable resources — solar, geothermal and wind generation — in California’s Imperial Valley region and communities in the Greater Los Angeles area.
Horizon West was chosen as the project’s developer over San Diego Gas & Electric, CalGrid, and Lotus Infrastructure Global Operations, LLC, in association with Southern California Edison Company.
Over the last few weeks, Palomar Mountain residents have begun noticing an increased presence of SDG&E workers. Several residents have received letters notifying them that SDG&E will be conducting environmental surveys in the area.
Bonnie Phelps, a Palomar Mountain resident and author of the Palomar Mountain News blog, said the workers were probing a potential route for the new power line before Horizon West won the project bid.
“This would be the largest transmission line carrying the most volts through San Diego County – and its route would be over Palomar,” Phelps told The Coast News prior to the bid selection announcement on April 29. “We cannot believe they would send the line through here.”
Phelps said Palomar Mountain State Park, the Cleveland National Forest and its surrounding areas are home to precious Native American historical sites, patches of old-growth forests and threatened and endangered species. She also said the power lines would cut through the Palomar Mountain community without providing power to the area.
While those might have been the plans for SDG&E, Horizon West officials said it’s still far too early to tell exactly where the power lines will be located.
“A detailed environmental assessment is being conducted to evaluate proposed routes, which will be shaped by input from stakeholders, environmental agencies, local governments, Indigenous Nations and other interested parties,” Horizon West’s website states.
The California Public Utilities Commission will have the final say on the power line’s route.
According to Horizon West officials, its permit application for the power line project is estimated to be submitted for review by late 2025 or early 2026 – though things could change by then.
The project will also require an environmental impact report that will be subject to public review and input prior to CPUC approval.
Horizon West is also in charge of developing the North Gila-Imperial Valley project, an 80-mile, 500-kv transmission line that would span southern Imperial County and connect the existing Imperial Valley substation to the North Gila substation in Yuma County, Arizona.
A subsidiary of NextEra Energy Transmission, Horizon West currently owns and operates transmission assets throughout the state as a regulated public utility.
According to the company, the North Gila-Imperial Valley project will be online by 2032 and the Imperial Valley-North of SONGS project in 2034.
“The proposed transmission lines would provide an important link between renewable resources in California’s Imperial Valley region and homes and businesses in the Greater Los Angeles area, as well as help California reach its clean energy goals and ensure its customers have reliable and affordable electricity as energy demands increase,” Horizon West asserts in a statement provided to The Coast News. “Selection marks an initial step in project development, which could be a multi-year process for each project and will require comprehensive studies and approvals by the California Public Utilities Commission.”
While Horizon West isn’t necessarily probing Palomar Mountain as a potential route for the Imperial Valley-North of SONGS power line, Phelps and other neighbors are keeping a close eye on the project. They plan to continue spreading the word and pushing back against any possibility that the route will cross the mountain.
“The narrative following this project is about going green, but you don’t go green at the expense of butchering the Cleveland National Forest, Palomar Mountain or endangered species,” she said.
