California Commission Approves Electric Resource Portfolios to Improve Reliability, Integrate More Renewable Energy

The California Public Utilities Commission on Feb. 20 approved electric resource portfolios to support transmission grid planning and help the state achieve its clean energy targets. The portfolios provide key information for the California Independent System Operator to optimize its 2025-2026 transmission planning to work toward climate goals while ensuring the reliability and affordability of electricity. The commission found that the portfolios would enable the state to integrate 60 gigawatts of new clean power generation and reduce greenhouse gas emissions to 25 million metric tons within the next decade.

The 2025 base case portfolio includes all renewable energy and energy storage assets procured or planned by every electric utility in their latest integrated resource plans. The adopted base case portfolios would achieve 99 percent clean energy serving retail load by 2035, which surpasses the 90 percent target stipulated in the 2022 Clean Energy, Jobs, and Affordability Act. Introducing new renewable energy resources is expected to steadily reduce the use of natural gas plants to generate electricity, with an estimated 71 percent decrease in annual natural gas generation by 2035 and up to 80 percent by 2040, compared to 2026 forecasts.

In its decision, the commission requested the grid operator to reserve deliverability on the transmission system for specific renewable energy sources that are still nascent or geographically limited, such as geothermal, biomass, offshore wind, and non-battery long-duration energy storage. The grid operator will also study new transmission investments to support some out-of-state wind and Northern California wind, which would require complex, long-term planning and regional cooperation.