ERCOT said Wednesday it will seek board approval for a potential price correction needed because of software errors that occurred on Feb. 15 when the grid operator shed 20 GW of load after losing half its generation at the height of a winter storm.
The grid operator said in a market notice that an initial staff analysis determined that the errors affected dispatch instructions for 79 intervals between 9:45 a.m. and 10:35 p.m. that day. Correcting the pricing errors would increase prices by 1 cent/MWh to $1,241.68/MWh, with an average increase of $58.36/MWh.
ERCOT said it also reviewed whether the programming error affected prices for the Feb. 16-17 operating days. However, it found that market prices for those days were already subject to the Public Utility Commission’s order that implemented $9,000/MWh scarcity pricing and were not affected.
The grid operator’s protocols allow it to take the price-correction request to its Board of Directors for approval. The board is scheduled to meet on April 13.
An ERCOT spokesperson said the Technical Advisory Committee will discuss the issue during its meeting on March 24.
Staff found that ERCOT’s market management system software contained programming errors that resulted in the use of an incorrect megawatt amount for the estimated deployed emergency response service (ERS) component of Security Constrained Economic Dispatch’s (SCED) real-time online reliability deployment price adder on Feb. 15. ERCOT was at its highest energy emergency alert that day and deployed all ERS resources. Those resources remained deployed during the EEA until their deployment obligations were exhausted.
ERCOT said that while it was able to determine accurate prices for the affected SCED intervals, it is still developing software fixes to address the noted issues.
The market notice attracted attention from some in the Texas media, given the current controversy over whether to reprice $16 billion of market transactions on Feb. 18-19. (See Texas Senate Passes Bill to Reprice ERCOT Feb. Sales.)
However, price corrections because of software input errors are not uncommon. Last October, the board approved price corrections for 25 operating days as a result of two unrelated events. (See “Board Approves 2 Sets of Price Corrections,” ERCOT Board of Directors Briefs: Oct. 13, 2020.)
ERCOT stakeholders subsequently approved a nodal protocol revision request (NPRR1024) that isn’t expected to go into effect until April 1. The measure requires ERCOT to seek board review of real-time prices if, within 30 days of the affected operating day, staff determines correcting an error would result in “an absolute value impact to any single counterparty” based on certain metrics.
The grid operator also alerted market participants that it has posted an application for gas facilities that provide fuel to generators so they can request designation as a “critical load-serving electric generation and cogeneration.”
Almost half of ERCOT’s natural gas-fired generation was lost during the winter weather because power was cut to gas infrastructure not listed as critical load.
