2025 California ISO Summer Loads and Resources Assessment Report posted

The California ISO has posted its 2025 Summer Loads and Resources Assessment Report and a Technical Appendix on its website. The files are available on the Seasonal assessments library page.

The 2025 Summer Loads and Resource Assessment (Summer Assessment) evaluates expected 2025 summer supply and demand conditions for the California Independent System Operator (ISO) balancing authority area (BAA). The ISO publishes and shares results of the Summer Assessment each year with state regulatory agencies, industry participants, and stakeholders. This Summer Assessment fits into a broader collaborative effort on behalf of the ISO, California Public Utilities Commission (CPUC), and California Energy Commission (CEC) to prepare for summer system operations and maintain grid reliability.

The Summer Assessment shows continued improvement in resource availability particularly driven by accelerated resource development. This results in an increase in projected capacity margins that exceed demand and reserve requirements and have met performance target levels three years in a row. The ISO’s probabilistic assessment of the anticipated 2025 summer conditions indicates a surplus meeting the “one day every 10 years loss-of-load expectation” (“1-in-10 LOLE”) planning target.

These results do not take into account more extreme events such as those demonstrated in the last several years, including extreme drought, wildfires and the continued potential for widespread regional heating events and other disruptions that can continue to pose reliability challenges for the ISO grid.