ISO8528-1:2018 defines basic generator set rating categories based on four operational Emergency Standby Power (ESP), Prime Power (PRP), Limited-Time Running Prime (LTP), and Continuous Power (COP)

COP means Continuous Power. The continuous power rating is used for applications without a grid power connection, or for units running grid-connected and exporting continuously, relying upon the generator set to provide a steady and constant load for an unlimited number of hours annually. Applications would include remote power plants, using multiple generator sets to achieve a constant load, a “base-load power station.” Baseload is the minimum amount of power that a utility must make available to meet a consumer’s demand for power.