Loss-of-Load Events

LOLEV. The number of events in which some system load is not served in a given year.

Last Updated:  June 20, 2025

Definition by NERC

Source:

Loss-of-Load Events (LOLEV) is the number of events in which some system load is not served in a given year. A LOLEV can last for one hour or for several contiguous hours and can involve the loss of one or several hundred megawatts of load. TRE-ERCOT is the only Assessment Area to provide this metric in its regional assessment.