Department of Market Monitoring 2025 Annual Report on Market Issues and Performance, call on 6/30/26

The California ISO's Department of Market Monitoring (DMM) has published the 2025 Annual Report on Market Issues and Performance on the Annual and quarterly reports webpage, and has scheduled a stakeholder call on June 30, 2026, to discuss reported analysis and findings.

Overall prices in the day-ahead and real-time markets were competitive, averaging close to what DMM estimates would result under highly efficient and competitive conditions, with most supply being offered at or near marginal operating cost. 

Prices across the Western Energy Imbalance Market (WEIM) were about 14 percent lower in 2025 compared to 2024 in the 15-minute market. Prices in the 15-minute market averaged about $34/MWh, while prices in the 5-minute market averaged about $35/MWh. Day-ahead market prices averaged about $39/MWh. Lower prices in 2025 occurred despite higher natural gas prices due to the absence of extreme conditions that led to high prices in Jan. 2024 and increased renewable generation. 

During mid-day solar hours, prices were generally higher in the Pacific Northwest, Northern California, and the Intermountain West than in the Desert Southwest and Southern California. This pattern was primarily driven by congestion on major transmission corridors in the south-to-north direction during solar production hours. During non-solar hours, California balancing authority areas had higher prices compared to the rest of the WEIM due mainly to California greenhouse gas pricing. 

Total battery capacity reached approximately 25,700 MW by the end of 2025. Average battery discharge peaked at about 9,100 MW in the evening hours, compared to about 5,700 MW in 2024.

Information related to market monitoring is available on the Market Monitoring webpage.

For questions, please contact Ryan Kurlinski at rkurlinski@caiso.com, and the Department of Market Monitoring at DMM@caiso.com.