Reserve
The generating capability that is “standing by” ready for service in the event that something happens on the power system.
Last Updated: June 22, 2025
Definition by PJM
Source:
Reserves represent the generating capability that is “standing by” ready for service in the event that something happens on the power system, such as the loss of a large generator. (Reference NERC Performance Standard BAL-002-1, Disturbance Control Performance, and PJM Manual 12, Attachment D). The severity of the event determines how quickly the reserves have to be picked up. Exhibit 6 illustrates how PJM classifies the different types of reserve services.