Diagnostic Marginal Unit

Units:	Yes/No
Default Value:	False (0)
Validation Rule:	False (0) or True (-1)
Description:	Execute region marginal unit diagnostic (this is an active diagnostic)

The Marginal Unit Diagnostic calculates the marginal unit for each Region in the system or for the whole system. This is calculated by performing a sensitivity analysis on regional load or system load for all periods in the simulation.

Marginal Unit Transmission Detail flag sets the units report level. Note that currently, Fixed shift factor OPF method does not support Regional setting in Marginal Unit Transmission Detail.

Note:

• In regional reporting, Region can be excluded from this diagnostic with the Region Include in Marginal Unit flag.
• Possible marginal units can be:
  • A physical object with controllable generation and/or load (Generator, Battery, Power2X etc.)
  • Purchaser
  • Physical Contract
  • Market.

The various steps that are involved in creating this diagnostic are as follows (for regional report):

1. Freeze certain decision variables (i.e. pumps, hydro's and the unit commitment), as we do not want these values to change during the sensitivity analysis
2. Optimize this problem so that we have a 'base' solution.
3. Get the current region's Load and increment this by the Marginal Unit Increment at the Reference Node
4. Optimize this problem
5. Retrieve the list of possible marginal objects across the system whose Generation/Load changed in response to the change in Load
6. Reset the Load for the Region
7. Print out the report for this Region
8. Go back to step (3) using the next Region in the system or until all Regions have been analyzed

The marginal unit diagnostic in no way modifies the solution values i.e. the solution database does not include any results from this diagnostic. The following table (Table 1) describes the values that are reported in the Marginal diagnostic.

Table 1 - Marginal Unit Diagnostic Property Description

Property Reported	Description
Year / Month / Day / Hour / Minute	The time and date of the period reported
Sample	The sample number that is being reported
Region Name*	The name of the region which the sensitivity analysis is being performed on
Region Shadow Price*	The locational marginal price (LMP) of the reference node (Node Price)
Uplift*	The uplift for the region (Region Uplift)
Region Price*	The price of the reported region (Region Price)
Marginal Region	The name of the region which the marginal unit belongs to
Marginal Change	The change in the marginal unit's generation in response to a one MW increase in region load. It is most commonly one but values other than unity indicate other units have increased or decreased their generation due to constraints.
Marginal Unit	The name of the marginal unit for the analysed region. This is a physical object such as a Generator or a Battery. If no marginal object can meet the demand sensitivity, USE will be reported
Marginal Market	The name of the marginal market for the analysed region. If no marginal object can meet the demand sensitivity, USE will be reported
Marginal Purchaser	The name of the marginal purchaser for the analysed region. If no marginal object can meet the demand sensitivity, USE will be reported
Marginal Generation Physical Contract	The name of the marginal generation physical contract for the analysed region. If no marginal object can meet the demand sensitivity, USE will be reported
Marginal Load Physical Contract	The name of the marginal load physical contract for the analysed region. If no marginal object can meet the demand sensitivity, USE will be reported
SRMC/Price	The Marginal SRMC or Market/Purchaser/Physical Contract Price
Load	The Region Load (excluding any increases performed by the diagnostic report)
Imports	The imports to the region (Region Imports)
Exports	The exports from the region (Region Exports)
Net Load	This is the Region Load + Region Net Interchange
Heat Rate	The marginal Heat Rate
Hydro Generation	The sum of all generation by the hydro generators in the region
Pump Generation	The sum of all generation by the pump generators in the region
Pump Load	The sum of all load for the pump generators in the region (Generator Pump Load)
Maintenance Outage	The sum of all generator maintenance outages in that region (Generator Maintenance)
Forced Outage	The sum of all generator forced outages in that region (Generator Forced Outage)
Fuel	The name of the fuel that the marginal unit is generating with. If there are no fuels then the name will reported as "None".
Fuel Price	The price of the fuel being used by the marginal unit (Fuel Price)
VOM Charge	The marginal VOM Charge
Wheeling Charge*	This is calculated by: Shadow Price - Marginal Unit's SRMC - ∑x (Emission (x) SRMC - Marginal Unit. SRMC where 'n' is the total number of emissions belonging to the marginal unit.
Unserved Energy	This is the unserved energy in the region (Region Unserved Energy)
Dump Energy	This is the dump energy in the region (Region Dump Energy)
Emission Rate	This is the marginal unit's incremental emission production value (Production Rate)
Emission Cost	This is the marginal unit's incremental emission cost. This is calculated by the following: Emission SRMC - SRMC

* items are for regional report only.