Who initiates an interconnection-wide Transmission Loading Procedure or authorizes a transmission relief process?

The correct choice is the Reliability Coordinator, as this entity has the responsibility and authority to oversee and manage the reliability of the power system over a wide area. The Reliability Coordinator is tasked with monitoring the status of the transmission system and ensuring it operates within acceptable limits. When there are signs that the system might experience overloads or reliability issues due to transmission constraints, the Reliability Coordinator can initiate an interconnection-wide Transmission Loading Procedure or authorize transmission relief processes. This proactive approach is critical for maintaining the stability and security of the grid, allowing for coordinated action among various entities involved in system operations.

In contrast, while the Balancing Authority manages the balance between generation and load within its area, it may lack the broader oversight necessary to enact interconnection-wide procedures. The Grid Operator typically refers to an individual managing operations at a more localized level rather than across multiple interconnected systems. The Transmission Owner is responsible for maintaining and operating the transmission infrastructure but does not possess the authority to implement system-wide procedures for reliability management like the Reliability Coordinator does.