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NPRR #486 · Revision Request

NPRR486  Calculation of Generation to be Dispatched

Withdrawn sponsor Luminant Energy Company LLC posted 2012-10-03 next action Consideration ercot.com
ReasonAs a result of the analysis of actual amounts of Regulation Service deployed on an hourly basis since the Nodal market implementation, it has been noted that the quantities of Regulation Service energy deployed have generally increased over time due to the bias toward Regulation Up Service (Reg-Up) compared to Regulation Down Service (Reg-Down). Additionally, there have been many hours where Regulation Service in only one direction has been deployed for the entire hour. Paragraph (2) of Protocol Section 6.5.7.3 specifies: "the SCED solution must monitor cumulative deployment of Regulation Services and ensure that Regulation Services deployment is minimized over time." In addition, paragraph (4)(b) of Protocol Section 6.5.7.6.2.1, Deployment of Regulation Service, requires that "ERCOT shall minimize Reg-Up and Reg-Down energy as much as practicable in each SCED cycle." Changing the current calculation of the generation to be dispatched input from using the sum of actual generation to using the sum of desired generation (i.e., Updated Desired Base Point), plus the amount of Regulation Service, will better minimize actual Regulation Service deployed. Data reviewed in the Qualified Scheduling Entity (QSE) Managers Working Group (QMWG) indicates there are many Generation Resources that have small deviations between actual output and desired output that are too insignificant to cause those Resources to fail Generation Resource Energy Deployment Performance (GREDP) metrics or incur Base Point deviation penalties, but that in aggregate, cause significant deployments of Reg-Up. For example, if 200 Generation Resources are On-Line and deviate from their Base Points by only one MW each in the same direction, the amount of Regulation Service deployed is consistently biased to deploy an extra 200 MW.
Created2012-10-18
Sections Affected
6.5.7.3
Summary
This Nodal Protocol Revision Request (NPRR) proposes revisions to specify the method for calculation of generation to be dispatched. This NPRR specifies that the generation to be dispatched input should be based on the sum of expected Updated Desired Base Points for all Generation Resources plus the amount of Regulation Service deployed at the time of the determination of GTBD for each execution of the Security-Constrained Economic Dispatch (SCED).
Timeline