California’s power grid is at a crossroads. With devastating wildfires, unpredictable weather, and aging infrastructure, the state is searching for solutions to make its electric system safer and more reliable. One of the most debated strategies is undergrounding power lines.
Proponents see it as the ultimate shield against catastrophe. Critics see a financial black hole. The question is not whether undergrounding works, but whether California can deploy it strategically without breaking ratepayer budgets.
The Case for the Trench: Safety at All Costs
The case for undergrounding rests on one overriding priority: eliminating catastrophic wildfire ignitions tied to overhead infrastructure. Faulty overhead lines sparked the 2018 Camp Fire and the 2021 Dixie Fire, two of the most destructive wildfires in state history. Burying power lines virtually eliminates the risk of high winds or falling branches igniting the next megafire. Beyond safety, removing the overhead web of wires improves property values and clears the skyline for California’s growing cities.
The Price of Undergrounding: $5 Million Per Mile
The biggest barrier for statewide undergrounding is the “math of the grid.” The price gap between overhead and underground lines is staggering:
- Overhead lines range from $634,000 to $760,000 per mile
- Undergrounding lines range from $1.85 million to $6.07 million per mile depending on the utility (PGE, SCE, or SDG&E). The urban average often trends towards $5 million or higher (California Public Utilities Commission, CPUC Undergrounding Programs Description, 2025).
PG&E’s goal to bury 10,000 miles of line carries a projected price tag exceeding $20 billion (American Society of Civil Engineers, 2021 and CalMatters, 2024).
The Hidden Complications
Even unlimited funding wouldn’t make a fully underground grid feasible. Other significant challenges include:
- Repair and Maintenance Issues: While underground lines are more protected from external damage, when something does go wrong, repairs can be complex and time-consuming. Unlike overhead lines, which can be easily inspected and fixed, underground systems require excavation and specialized equipment to locate and repair faults.
- Seismic Vulnerability: In a state defined by fault lines, shifting soil can crush or snap buried conduits, leading to repairs that are far more invasive than up-righting a pole.
- The Construction Nightmare: The process of burying power lines involves extensive trenching, road closures, and environmental impacts, making large-scale projects difficult in urban and environmentally sensitive areas.
The Middle Ground: A Targeted Hybrid
Because a 100% underground grid is financially impossible, costing upward $800 billion (CPUC Undergrounding Programs Description, 2025), California is pivoting to a risk-based approach. Utilities are prioritizing:
- High Fire Threat Districts (HFTDs) for undergrounding
- Covered conductors in moderate risk zones
- Remote fault indicators and smart reclosers to reduce ignition risk
- AI-enabled vegetation management to identify hotspots before they become hazards
New technologies are helping narrow the cost gap. Micro-trenching and prefabricated cable systems reduce excavation burdens and increase deployment speed, particularly in select urban corridors.
The Practical Verdict
Undergrounding power lines would enhance safety, reduce wildfires, and improve grid reliability in California. However, the price tag and logistical hurdles of a full-scale statewide undergrounding project would make electricity a luxury few Californians could afford. California’s most realistic path forward is a strategic, hybrid model focused on the highest‑risk wildfire zones, supplemented by modern overhead hardening and digital grid tools elsewhere.
The Bottom Line
California’s future grid will be neither fully overhead nor fully underground. The utilities that lead this transition will be those that deploy undergrounding where it matters most, strengthen overhead systems where it is more practical, and leverage technology to reduce wildfire risk without placing unsustainable burdens on ratepayers.
