What the Golden Pacific Powerlink actually is

Project overview

The Golden Pacific Powerlink is a proposed 500 kV extra-high-voltage transmission line from San Diego Gas & Electric (SDG&E), a regulated investor-owned utility whose service territory is San Diego and Orange counties — not Riverside County. Its parent company is Sempra Energy.

SDG&E says the line is needed to meet CAISO's 2022–2023 transmission planning requirements, moving power from southwestern generation areas to Southern California population centers, with a target commercial operation date of 2032 (CAISO's latest required in-service date is June 1, 2034). EHV lines like this typically carry 1,000–2,000 megawatts.

The core grievance: the corridor would route 500 kV towers through Temecula while delivering no direct benefit to the Riverside County residents who'd live beneath them.

The Temecula segment

The preliminary corridor runs from a proposed new substation north of SONGS eastward through Temecula, across the county line toward Palomar Mountain, and down to the existing Imperial Valley Substation. The contested portion in Temecula primarily follows the Temecula Creek corridor — land zoned Open Space Conservation — passing near Vail Ranch Middle School, the Santa Margarita River, and Pechanga tribal land.

Across its full length, the line is roughly 135–145 miles of 500 kV transmission, which CAISO estimated at about $2.3 billion in its Project Sponsor Selection Report (May 9, 2024). That figure is a CAISO planning estimate, not a final cost — SDG&E has not yet published its own, which is expected with its CPUC application. Only about 5 miles run through Temecula — the contested segment detailed below.

Voltage

500 kV extra-high-voltage

Within city limits

~5 miles, I-15 to Anza Rd

Structures

Steel lattice towers (~15–21, est.)

Tower height

~125–200 ft (≈12–20 stories)

Span between towers

~1,400–1,800 ft (4–6 football fields)

Right-of-way

~200–250 ft (more on terrain)

Study corridor

1,000 ft wide (not the final RoW)

Land

Temecula Creek — Open Space Conservation

Height, span, right-of-way, and the 1,000-ft corridor are figures put on the record at the May 26 Council meeting; the tower count is a community estimate (SDG&E gave none), and SDG&E says engineering is still preliminary — so several are ranges.

See it on a map

Why here? Because of what the State already ruled out. When the California Energy Commission studied a 500 kV crossing of this area in a 2014 feasibility report, it catalogued the ground a line effectively cannot take: the Agua Tibia Wilderness (“a transmission corridor would not be compatible with wilderness lands”), the Pechanga Reservation — whose Nation “did not give its consent … and there is no indication that it would” — the restricted roadless areas of Cleveland National Forest, and the Santa Margarita Ecological Reserve. Two more are gated rather than barred: the Southwestern Riverside County Multi-Species Reserve, whose integrity ten local agencies' permits depend on, and Interstate 15 — Caltrans has approved “no longitudinal encroachments” on freeway right-of-way, which is what rules out the intuitive answer of just running it down the freeway.

Stack those and the geography does the arguing. Agua Tibia and Pechanga together, in the Commission's own words, “block north-south access between San Diego and Riverside Counties along a 12-mile stretch of the county line.” Eliminate the wilderness, the reservation, the restricted forest, the reserve and the freeway, and a north–south crossing has almost nowhere left to thread except the gap west of the Wilderness and north of the reservation — the developed floor of Temecula. That is the window the Commission rated “Very Challenging,” its worst tier, and where it said an overhead route “is unlikely.” So the finding isn't “the route is X” — it's that the constraints leave no good overhead route at all. The map below puts the no-go zones and the reported corridor on the same picture.

Every quote above is from that report — Transmission Options and Potential Corridor Designations in Southern California in Response to Closure of San Onofre Nuclear Generating Station (SONGS), prepared for the Energy Commission by Aspen Environmental Group, Publication CEC-700-2014-002, May 2014 (the constraint catalog is Table 5; archived copy, if the State's link ever moves). Read it yourself; it is a public document. One caveat we hold to: that study screened different endpoints than today's line, so nothing here claims the State reviewed this project. What carries over is the geography — a wilderness, a reservation, a national forest and a freeway rule don't move when the endpoints change.

Use the legend to switch layers on and off. Beyond the corridor and the no-go zones, there is a half-kilometer impact band — about 4,200 homes sit inside it — a street-by-street layer labeling how many homes on each street fall in the band, and a separate layer for the businesses, offices, medical buildings and shopping centers along Temecula Parkway that sit in the same corridor.

About this map: it is a reasoned overlay, not a survey. It is not SDG&E's filed alignment — that has not been published. The corridor line is the route reported publicly, and the legs drawn west through De Luz and southeast to Warner Springs are traced by hand along the highway the State itself named, marked on the map as illustrative. The Wilderness, Reservation and National Forest boundaries are the official ones (U.S. Forest Service and Census Bureau data); the ecological reserve, the multi-species reserve and the I-15 barrier are drawn approximately and labeled as such. Please don't read acreages or “miles crossed” off it.

How it gets approved

Transmission lines above 50 kV are approved by the California Public Utilities Commission (CPUC) — five commissioners appointed by the Governor. SDG&E's own materials lay out a five-step process, and Temecula was only notified at step 4, after the project had already been planned and bid accepted by CAISO:

1. 1California Energy Commission (CEC) — forecasts statewide energy demand.
2. 2CPUC — sets generation/storage planning via the Integrated Resource Plan.
3. 3CAISO — decides where lines go and picks the solution in its Transmission Plan.
4. 4SDG&E — early engineering, environmental studies, community outreach. (← Temecula first notified here.)
5. 5CPUC + state/federal agencies — review under CEQA/NEPA, approve, and grant rights-of-way.

What was said on the record

Much of what we know comes from one public, on-the-record accounting — the May 26, 2026 City Council meeting, where SDG&E, the California ISO, and City staff laid out the project and took questions. Each statement below links to the exact moment in the meeting video so you can hear it in context.

See the full meeting — context, public testimony, and the Council's 5–0 vote to oppose the route — on the meeting page.

The bid: four routes, only one through a neighborhood

Before SDG&E ever took it over, the project went out for competitive bid through the California ISO in 2023. CAISO's own list of qualified applicants shows four companies submitted routes. CAISO picked Horizon West's — and according to CAISO's own Project Sponsor Selection Report (May 9, 2024), it was the only one of the four whose route ran through an urban area.

• Horizon West TransmissionSelectedThe only one of the four to route through an urban area.
• San Diego Gas & ElectricNon-urban route; crossed U.S. Forest Service land.
• Lotus Infrastructure / Southern California EdisonNon-urban route; crossed Forest Service and tribal land.
• California Grid Holdings (CalGrid)Non-urban route; crossed Forest Service and tribal land.

“Horizon West proposed a route that would traverse an urban area. The ISO understands that routing transmission facilities in urban areas poses a risk of public opposition, which can negatively impact budget and schedule risk.”— CAISO Project Sponsor Selection Report, May 9, 2024

CAISO acknowledged that risk in writing and selected the route anyway, judging that Horizon West had enough schedule “float” to absorb the delay. SDG&E — itself a losing bidder, with a non-urban route of its own — then took over the winning project's transmission line in summer 2025, so it is now building the Temecula route it did not originally propose. The full bids and the competing route maps remain confidential; only the selection report is public.

The May 26 Council exchange named only three bidders (Horizon West, SDG&E, California Grid); the fourth, named in CAISO's applicant list, was the Lotus Infrastructure / Southern California Edison team. CAISO's report says “an urban area,” not Temecula by name — the Temecula identification comes from the line's preliminary corridor.

It's been stopped here before

This is not the first time SDG&E has tried to push a 500 kV line through this region. In 2002, the CPUC denied the Valley-Rainbow Interconnect — a 500 kV line in this same southwest-Riverside corridor — because the company could not prove it was needed. In 2008, regulators rejected the Sunrise Powerlink's route through Anza-Borrego as “environmentally unacceptable and infeasible,” forcing it off the park. And from 2008 to 2012, this community and the Pechanga defeated the Liberty Quarry on the same county border.

See how these fights were won →