EcoMax and Dispatch Setpoint are set in Real-Time Unit Dispatch System (RT UDS) for Dispatchable Intermittent Resources (DIR) when the it is on-control (control status = 1). The logic used for EcoMax and Dispatch are as follows:
EcoMax:
1. If there is an operator EcoMax override on the resource, the override value will be used as the Forecast Maximum Limit.
2. If the DIR Asset Owner submitted a DIR forecast, RT UDS will use the MP submitted DIR forecast (timing and values are validated).
3. If the Real-Time capability forecast submitted by the DIR Asset Owner is not provided, or is submitted to the MUI more than 30 minutes prior to the UDS interval end-time, or the value submitted is larger than the Resource’s DIR Feasibility limit times a technical margin, then the Real-Time capability forecast generated by MISO will be used as the Forecast Maximum Limit.
4. If the Real-Time capability forecast generated by MISO is not provided, or is generated more than 30 minutes prior to the UDS interval end-time, or the value is larger than the Resource’s DIR Feasibility limit times a technical margin, then the most recent State Estimated output for the DIR will be used as the Forecast Maximum Limit.
Dispatch:
1. If the unit’s offer price is less than Locational Marginal Price (LMP), the unit is “in the money”, and the MP submitted EcoMax is used.
2. If the unit’s offer price is greater than LMP, it is dispatched down, using the Economic Dispatch determined value (Bounded by MP submitted EcoMin and EcoMax limits and the unit ramp rate).
3. If the unit’s offer price is the same as LMP, it is a marginal unit and is dispatched down, using Economic Dispatch determined value
When the Dispatch Setpoint is less than EcoMax and the DIR unit is on control, the unit is dispatched down. This is usually caused by the unit’s offer price being greater than or equal to LMP.
Reference: BPM-002 Energy and Operating Reserve Markets (See DIR Forecast Maximum Limit)