Energy Management System (EMS)

In a grid-operations context, an Energy Management System is the software platform grid operators use to monitor and optimize power generation and delivery in real time, including functions like Automatic Generation Control, load forecasting, and contingency analysis. It's distinct from SCADA: SCADA provides the underlying real-time monitoring and control of field equipment, while an EMS layers higher-level optimization and decision-support functions on top of that SCADA data.

Note: this grid-operations meaning is distinct from a building-focused "energy management system" used for HVAC and lighting efficiency, which is a different, unrelated use of the same term.