NERC System Operator (SOS) Practice Exam 2025 – Complete All-in-One Guide for Exam Success!

The acronym ACE in the context of Balancing Authorities stands for Area Control Error. This metric is crucial for Balancing Authorities as it represents the difference between the scheduled and actual power flow across the boundaries of control areas. It is measured in megawatts (MW) and plays a vital role in maintaining the reliability and security of the electric grid.

ACE helps operators determine if they are meeting their load obligations and maintaining the proper frequency. A positive ACE indicates that the actual generation is less than the scheduled generation, while a negative ACE indicates the opposite. By monitoring and correcting ACE, Balancing Authorities can make real-time adjustments to generation and load, promoting both stability and efficiency within the interconnected power system.

Understanding ACE is fundamental for system operators as it forms the basis for their actions to balance supply and demand in real time, ensuring that generation matches load within specific tolerances, thus contributing to the overall reliability of the grid.