Title: Remove NPRR153 Grey Boxes and Clarify Fixed Quantity Block Treatment in the DAM
Next Group:
Next Step:
Status: Approved on 11/19/2013
Effective Dates:


Date Gov Body Action Taken Next Steps
11/19/2013 BOARD Approved
09/05/2013 TAC Recommended for Approval ERCOT Board consideration of NPRR548
08/22/2013 PRS Recommended for Approval TAC consideration of NPRR548
07/18/2013 PRS Recommended for Approval PRS Impact Analysis review

Voting Record

Date Gov Body Motion Result
11/19/2013 BOARD To approve NPRR548 as recommended by TAC in the 9/5/13 TAC Report. Passed
09/05/2013 TAC To recommend approval of NPRR548 as recommended by PRS in the 8/22/13 PRS Report. Passed
08/22/2013 PRS To endorse and forward the 7/18/13 PRS Report as amended by the 8/20/13 ERCOT comments and Impact Analysis for NPRR548 to TAC. Passed
07/18/2013 PRS To recommend approval of NPRR548 as revised by PRS and to request that WMS review NPRR548 and submit comments. Passed

Vote tallies here reflect individual votes, not the weight of the votes by market segment. Affirmative votes are not recorded in these vote tallies. For additional details on the voting record, please consult the Recommendation or Action Report, or the official vote tally if available, as posted in the key documents.


Status: Approved
Date Posted: Jun 21, 2013
Sponsor: ERCOT
Urgent: No
Sections:,,, 4.5.1
Description: This Nodal Protocol Revision Request (NPRR) removes the grey boxes that are pending implementation of system changes associated with NPRR153, Generation Resource Fixed Quantity Block. Further, this NPRR provides clarification for how the Day-Ahead Market (DAM) currently considers blocked offers and bids for Ancillary Services.
Reason: The ERCOT Board approved NPRR153 on 1/19/10, and on 11/13/12 assigned a priority of 2013 and rank of 790 for the associated project. Recently, at the 5/8/13 WMS meeting and 6/4/13 Qualified Scheduling Entity (QSE) Managers Working Group (QMWG) meeting, ERCOT discussed with Market Participants the potential market clearing price impacts of implementing NPRR153, namely that clearing prices could be artificially reduced. While currently the DAM has fixed quantity blocks for energy, because the Ancillary Services market is much smaller, the magnitude of the price difference between the marginal offer price and the clearing price could be large. This NPRR is a result of those discussions and will remove the NPRR153 grey boxes to eliminate the requirement and implementation. Further, ERCOT believes it would be beneficial to clarify the way that the DAM is designed to price and clear fixed quantity blocks. Due to the nature of the market design and mixed integer programming clearing process, fixed quantity block bids can clear at prices that exceed their bid price, and fixed quantity block offers can clear at prices that are below their offer price, when the blocks are marginal. Block offers and bids do not set the clearing price and are essentially price-takers once selected in the commitment phase of the DAM. Further, fixed quantity blocks may fail to clear when seemingly economic based on the final Settlement Point Price. The language introduced in Section 4.5.1 clarifies that, for certain products, the clearing prices are subject to these inconsistent pricing scenarios. The intent is to improve market education and minimize disputes based on this market design construct.

Key Documents

Related Content