Transmission Utilization

The utilization map illustrates the estimated historical utilization of the transmission system in 2022. The utilization values are estimated using the historical hourly load and generation dispatches, the normally in-service configuration, and seasonal thermal ratings of the transmission system as of Dec. 31, 2022, and the most critical contingency for each transmission line.   

It is important to note that the utilization results on the map are based solely on thermal ratings and do not account for other factors that may affect transmission system utilization, such as the need to plan and build transmission infrastructure at an economically optimal scale, or system-related constraints that may be more stringent than the thermal ratings. Although utilization is a consideration in transmission planning and development, it is not a sufficient factor to evaluate the need, feasibility, and impact of a specific transmission project. The need for transmission capacity expansion is approved in a formal regulatory application and approval process. For more information on each transmission project, please see Transmission Projects and Long-term Transmission Plan. 

It's also important to note that the utilization of each transmission line does provide an indicator of the remaining capacity on each line individually. However, because it does not consider system-related constraints, it is not the estimated additional capacity (capability) that could be connected to the transmission line or the substation(s) linked with that line. Please use the Transmission Capability Map for information related to transmission capability.