California's Pacific Gas and Electric Company has filed a proposed 10-Year Electrical Undergrounding Plan with the California Office of Energy Infrastructure Safety that would place approximately 5,000 miles of electric distribution lines underground from 2028 to 2037 in locations where undergrounding is forecasted to provide the greatest reduction in wildfire risk.
In these areas, undergrounding power lines can reduce ignition risk by nearly 98% and improve reliability with 90% fewer outages, it said.
PG&E estimates that completing 5,000 miles of undergrounding will also save customers approximately $6 billion in vegetation management, operations and maintenance costs over the life of these assets. The plan includes work in more than 30 Northern and Central California counties.
PG&E estimates the plan will deliver long-term benefits valued at $117 billion by helping prevent wildfires and reduce outages, which is more than 10 times the value of the proposed investment, while avoiding approximately $6 billion in future vegetation management, operations and maintenance costs over the lifespan of the underground assets.
Over the last few years, PG&E has reduced its undergrounding cost per mile by approximately 25%, it said. The company expects a 10-year plan to enable continued improvements in planning, construction practices and supply chain coordination to help further improve efficiency and reduce costs over time.
The proposal will be reviewed by Energy Safety, which will evaluate whether the plan substantially increases reliability and substantially reduces wildfire risk. If the plan is approved, PG&E will submit the plan and an application to the California Public Utilities Commission requesting conditional approval of the plan's costs.
A key feature of the plan is PG&E's use of advanced data analytics and risk modeling to forecast where undergrounding will provide the greatest benefits for customers and communities.
The company's risk-based approach considers wildfire likelihood and consequence, system reliability, customer impacts, project costs and benefits, and how undergrounding compares with other wildfire mitigations.
When undergrounding is not the best fit for a given location, PG&E may deploy other system upgrade measures, including installing strengthened poles, covered powerlines and other overhead system upgrades. This approach helps direct investments toward the solutions that provide the greatest overall value to customers while maintaining a strong focus on safety and reliability.
By the end of 2027, PG&E plans to have completed more than 1,900 miles of undergrounding and approximately 2,000 miles of overhead system upgrades in high wildfire-risk areas, since the programs started.
Combined with the proposed 10-year EUP mileage and additional overhead system upgrade work, PG&E expects to underground or upgrade more than 11,000 miles of powerlines in high wildfire-risk areas by the end of 2037, subject to regulatory approval.
The complete filing, including a forecasted county workplan list, is available at pge.com/eup.
