How often is the hourly ATC calculated for the next 48 hours?

The calculation of Available Transfer Capability (ATC) typically occurs every hour for the next 48 hours to ensure that the system has up-to-date information for operational planning and reliability assessments. This hourly recalibration allows for timely adjustments based on the latest data, ensuring that operational entities can respond appropriately to changing grid conditions.

Calculating ATC every hour enhances the reliability of the transmission system, as it accounts for variations in generation, load levels, and network topology that can affect the amount of capacity that is available to transfer power. While 30-minute intervals could offer a more dynamic approach, the standard practice is to perform the ATC calculation on an hourly basis, making option B the correct choice.