What type of metering must each Balancing Authority have on their tie-line with other BAs?

The requirement for Balancing Authorities to have metering on their tie-lines with other Balancing Authorities is grounded in the need to accurately monitor and manage the flow of electric energy and ensure the reliability of the grid. The correct answer specifies that Balancing Authorities must measure both Megawatts (MW) and Megawatt-hours (MWh).

Megawatts reflect the instantaneous power flow on the tie-line, which is crucial for real-time operational decision-making. This measurement helps Balancing Authorities understand how much power is being transferred at any given moment, thus allowing them to balance supply and demand effectively.

On the other hand, Megawatt-hours provide a cumulative measure of the energy transferred over time. This is essential for recordkeeping and aids in understanding total energy exchanges over specific periods, which can be important for financial settlements and planning future power availability.

Other types of metering, such as power factor, voltage, frequency, phase angle, current, and impedance, do not provide the critical information needed specifically for balancing and managing electric power supply and demand across tie-lines as comprehensively as MW and MWh do. While these measurements may be important in different contexts, they do not directly relate to the core responsibilities of a Balancing Authority regarding tie-line