In recent years, California has brought an unprecedented amount of new clean energy and storage resources into operation to meet climate goals and reliability needs and keep pace with increasing electrification of the building and transportation sectors. California added 17,200 megawatts (MW) of new energy resources to the California Independent System Operator (California ISO) transmission system from 2020 to 2023. In 2023 alone, nearly 6,300 MW were added, primarily from solar and storage resources.  

To achieve the targets set by Senate Bill 100 (De León, 2018) of 100 percent clean electricity by 2045, the state must maintain this rapid pace of new resource development. This will require successful implementation of the California ISO recent transmission plans and interconnection queue reform, among other efforts, aimed at streamlining transmission development.  

Investment in new and upgraded transmission system infrastructure is crucial for meeting reliability and policy objectives. This requires a focused effort to ensure the timely completion of transmission projects that vary widely in scale and complexity, from localized network upgrades to major new transmission lines. Although some transmission projects involve relatively simple upgrades to existing equipment, larger transmission projects require long lead times to permit and construct due to their scale, cost, impact, and complexity.   

Modernizing the transmission grid, through capacity expansion and maintenance projects, must be prioritized along with efforts to upgrade the distribution system, energize new customers and enhance the overall safety and resiliency of the electricity system, particularly against climate-driven wildfires. This push to accelerate transmission build-out also coincides with rising global competition for equipment and skilled labor. And adding to the challenge is the critical need focus on affordability while facilitating the timely construction of needed infrastructure.  

This confluence of demands—from upgrading aging infrastructure to supporting rapid electrification in transportation and building sectors—creates a uniquely challenging environment that can delay development timelines. Facilitating the timely buildout of needed infrastructure in light of these interrelated challenges and priorities require coordinated and strategic approaches. 

A map of California that shows how transmission lines of various size criss-cross the state.