Ancillary Services Scarcity Event on 4/11/25

The California ISO has an ancillary services scarcity pricing mechanism in place that is triggered when the ISO is unable to procure the target quantity of one or more ancillary services in the integrated forward market or real-time market runs.

On April 11, ancillary service scarcity occurred in the 15-minute market run for the following region, service and quantity:

Trade

Date

Hour Ending

Interval

Ancillary Service

Region

Shortfall (MW)

Percentage of Requirement

April 11

Regulation Down

NP26_EXP

6.96

1.2%

The ISO confirmed the scarcity event during its price correction process. The published ancillary services prices correctly reflect the approved administrative set of scarcity prices.

Contact information

Please contact Jennie Araj at 916-351-2165 or jaraj@caiso.com with any questions.