What timeframe is specified for updating changes to the operating plan concerning backup facilities?

The correct timeframe specified for updating changes to the operating plan concerning backup facilities is 60 calendar days. This requirement ensures that all relevant entities have a standardized period to document and communicate any modifications to their backup facilities, which are critical for maintaining reliability in the electric grid. Timely updates are essential for coordination among different reliability coordinators, as they help in assessing and responding to potential impacts on system reliability. The 60-day period allows sufficient time for the necessary assessments and communication to occur, enhancing overall operational preparedness and risk management for entities involved in grid management.