PJM will resettle $89 million in bills due to logging errors that caused overcharges of load serving entities in the eastern portion of PJM and undercharges for those in the west. The improperly inputted data incorrectly placed RTO-wide charges entirely in the eastern zones, PJM’s Joe Ciabattoni told the Market Implementation Committee last week.

Ciabattoni said an unusual transaction code used during the polar vortex led to a “misunderstanding in the control room.” The “regional conservative operations” code has since been eliminated.

Suzanne Coyne, of PJM Settlements, said the issue was discovered in February and adjustments were made in the March bills, which were distributed last week.