CAISO precedent for cancellation of the SDGE Gold Powerlink

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In May 2026, the California Independent System Operator (CAISO) Board of Governors formally cancelled the Serrano–Del Amo–Mesa 500-kV Transmission Reinforcement project in the Los Angeles Basin.

This cancellation provides the exact playbook needed to defeat the Golden Pacific Powerlink and preserve Palomar Mountain, Warner Springs, and Anza-Borrego Desert State Park from catastrophic destruction.

The Serrano-Del Amo-Mesa Precedent: Skyrocketing Costs & Modern Alternatives

The Serrano-Del Amo-Mesa project was approved during the exact same 2022–2023 CAISO transmission planning cycle as the Golden Pacific Powerlink. However, once real-world engineering took place, the project collapsed under its own weight:

• The Multi-Billion Dollar Reality Check: Initially projected to cost $1.125 billion, Southern California Edison’s detailed engineering phase revealed the true price tag had skyrocketed to $5 billion—a massive 350% increase.
• The Grid-Enhancing Solution: Rather than forcing a costly, outdated megaproject on California ratepayers, CAISO pivotally chose to meet grid reliability through 12 discrete reconductoring projects utilizing advanced grid-enhancing technologies (GETs) and expanded energy storage systems (BESS).

How the Two Projects Stack Up

Voltage & Scope

• Serrano-Del Amo-Mesa Project: 500-kV Transmission Reinforcement
• Golden Pacific Powerlink: 145-to-150-mile, 500-kV Transmission Line

Initial Estimated Cost

• Serrano-Del Amo-Mesa Project: $1.125 Billion
• Golden Pacific Powerlink: $1.6 to $2.3 Billion (Base Estimate)

True Cost Exposure

• Serrano-Del Amo-Mesa Project: Ballooned to $5 Billion before cancellation
• Golden Pacific Powerlink: Expected to skyrocket similarly through complex mountain terrain

CAISO Current Status

• Serrano-Del Amo-Mesa Project: Officially Cancelled (May 2026)
• Golden Pacific Powerlink: Soon under Active CPUC Review / Public Opposition

Proposed Solution

• Serrano-Del Amo-Mesa Project: Reconductoring existing lines & localized battery storage
• Golden Pacific Powerlink: Current: Up to 200-ft steel towers slicing through state parks and mountain communities

Why the Golden Pacific Powerlink is the Wrong Choice for California

SDGE claims the Golden Pacific Powerlink is vital for statewide grid reliability. However, just like the cancelled Serrano project, the proposed 145-mile line relying on towers up to 20 stories tall represents an archaic approach to modern energy management.

1. Astronomical Wildfire and Safety Risks

Placing massive 500-kV lines through Palomar Mountain or the Highway 79 corridor creates an existential wildfire threat. These massive towers severely limit aerial firefighting capabilities, making it impossible for water-dropping helicopters to maneuver and protect backcountry communities during a firestorm.

2. Destruction of Irreplaceable Public and Cultural Lands

The preferred and alternative routes threaten to slice through the heart of Anza-Borrego Desert State Park, de-designating protected State Wilderness. The routes also cross over sensitive ecosystems on Palomar Mountain, the Temecula Wine Country, and directly threaten ancestral cultural resources belonging to local Native American tribes, drawing heavy condemnation from the City of Temecula and the Pechanga Tribe.

3. Local Communities Bear the Cost, Orange County Gets the Power

Rural San Diego and Riverside communities are expected to absorb 100% of the environmental degradation, visual blight, and fire risk, while the electricity is predominantly routed to coastal hubs in Orange and Los Angeles counties. 

Worse yet, local jurisdictions have no voting power or permitting authority over the alignment, as the decision rests solely with the state.

Demand a Smarter Grid: Take Action Today

The cancellation of the Serrano-Mesa line proves that CAISO can and will drop multi-billion dollar transmission lines when ratepayers and communities demand fiscal and environmental responsibility. 

We must force the California Public Utilities Commission (CPUC) and CAISO to apply the exact same logic to the Golden Pacific Powerlink.

How You Can Help Fight Back:

• Submit a Formal Comment: Let the CPUC Public Advisor’s Office know that safer, cheaper alternatives—like energy storage and reconductoring existing corridors—must take precedence over destroying Palomar Mountain. We provided a template for such letter here.
• Sign the Coalition Petitions:  

- SavePalomarMountain petition is here, and you can find the more than 2,000 signatories here.

- SaveTemecula petition is here.

- SaveWarnerSprings petition is here

• Consult Anza Borrego "Take action" tool kit here
• Make a donation to support our efforts (legal expense, expert support, outreach programs...)