Power system reliability maintained during Sunday evening reserve shortage

ISO New England declared a Power Caution on the evening of Sunday, Nov. 23, due to an unexpected loss of generation during the evening peak period. This was not a system emergency.

The unexpected generation loss occurred at about 5:41 p.m., leaving the region unable to meet its operating reserve requirement. The timing of the generation loss, coupled with consumer demand being slightly higher than expected, meant other resources could not immediately fill the gap. Specific generators are not identified per the ISO’s Information Policy.

ISO-NE’s highly trained system operators followed established procedures to maintain system reliability during the shortage period, and ended the Power Caution at 7 p.m. A corresponding abnormal system conditions alert remained in effect until 9 p.m.

Preliminary information indicates the system event will trigger the region’s Forward Capacity Market Pay-for-Performance rules. The ISO is evaluating market data and will provide more information when it is available.