What does the ACE value represent for a Balancing Authority?

The ACE, or Area Control Error, represents the difference between the actual and scheduled interchange with neighboring Balancing Authorities, adjusted for the frequency bias. It is a critical measurement for a Balancing Authority, as it indicates how well the generation and load are balanced within a specific area.

When the ACE value is zero, it signifies that the generation is perfectly matched with the load and the interchange with other areas is as planned, reflecting an ideal load generation balance. If the ACE is positive, it indicates that actual generation is higher than scheduled, suggesting excess generation, while a negative ACE indicates under-generation relative to scheduled levels.

This balance is essential for maintaining system stability and ensuring reliable operation of the electric grid, as discrepancies can lead to frequency imbalances and potential system issues.