CAISO Contingency Reserve Requirement Change effective 11/4/26

The California ISO (ISO) Balancing Authority (BA) will remove the additional reserve requirement equal to 3 percent of generation plus 3 percent of load from its contingency reserve calculations effective with the Nov. 4, 2026, trade date. This change completes ISO BA’s implementation of North American Electric Reliability Corporation (NERC) BAL-002 following the retirement of BAL-002-WECC on July 1, 2026.

The ISO BA procures Regulation, Spinning Reserve, and Non-Spinning Reserve in the Day-Ahead Market (DAM) and Real-Time Market (RTM) to ensure total reserve procurement meets or exceeds requirements established using the Most Severe Single Contingency (MSSC) criteria, consistent with NERC BAL-002-3. Ancillary Services are procured at the lowest overall cost while maintaining market competitiveness and system reliability.

Additional information on related operating procedure revisions removing the 3 percent generation plus 3 percent load requirement is available in the notice published on July 1, 2026. 

Please contact ISO Customer Service at 916-608-7320 with any questions.