September 17, 2007 ARC Event

Monday September 17, 2007 from 19:35 EST through 20:15 EST the Midwest ISO invoked the ARC procedure due to 700 MW Net Scheduled Interchange obligation over a ten minute period and evening peak load coming in 1,100 MW higher than projected. Up to 75% of the available ARC operating reserves were utilized during this period to correct the imbalance. There were no ARS events during the procedure.