NOTICE DATE: September 16, 2026

NOTICE TYPE: M-A091626-01 Settlements

SHORT DESCRIPTION: Resolution of NRG ADR proceeding (ADR No. 2026-NRG-01); Refund to be reflected in RTM True-Up Statements for Operating Day March 23, 2026

INTENDED AUDIENCE: All Market Participants

DAYS AFFECTED: September 21, 2026

LONG DESCRIPTION: ERCOT has granted Alternative Dispute Resolution (ADR) proceeding No. 2026-NRG-01 initiated by NRG Texas Power LLC (NRG) concerning a $229,614.35 RUC Clawback Charge.  In accordance with Protocols Section 20.9(1), ERCOT issues this Market Notice providing a description of the relevant facts underlying the ADR; a list of the parties involved in the ADR; and a summary of ERCOT's disposition of the ADR and its reasoning in support thereof.

Further, in accordance with Protocols Section 20.9(2), ERCOT hereby provides notice that ERCOT's refund of the $229,614.35 RUC Clawback Charge will be reflected in the Real-Time Market (RTM) True-Up Statements for Operating Day (OD) March 23, 2026, which will be issued on September 21, 2026.

Parties: NRG and ERCOT.

Relevant Facts: At 12:25 a.m. on March 23, 2026, NRG received a RUC instruction for one of its Generation Resources (the Resource) for Operating Hours Ending 19:00 through 23:00 on OD March 23.  At 12:33 a.m. that same morning, NRG changed the Resource's COP Status to "ONOPTOUT," thereby opting out of the RUC pursuant to Protocols Section 5.5.2(21).  Though NRG timely opted out of the RUC, an error in ERCOT's RUC Opt-Out Snapshot application caused ERCOT's systems to treat the Resource as having not opted out. NRG was accordingly assessed a $229,614.35 RUC Clawback Charge pursuant to Protocols Section 5.7.2.

ERCOT's Disposition and Reasoning:  Protocols Sections 5.5.2(21) and 2.1 ("RUC Opt-Out Snapshot") provide a process by which Market Participants may opt out of a RUC instruction and instead choose to self-commit their resource(s).  In this case, NRG timely and properly opted out of the RUC instruction it received on OD March 23, 2026.  Because of an error in ERCOT's RUC Opt-Out Snapshot application, as described in Market Notice M-B040126-01, NRG was prevented from opting out of the RUC and was assessed a $229,614.35 RUC Clawback Charge.  ERCOT did not identify any other action NRG should have taken to avoid the RUC Clawback Charge. ERCOT therefore grants NRG's requested refund of the RUC Clawback Charge.

Adjustments to September 21, 2026 RTM True-Up Statements: ERCOT's refund of the $229,614.35 RUC Clawback Charge will be reflected in the RTM True-Up Statements for OD March 23, 2026, which will be issued on September 21, 2026.  Her

CONTACT: If you have any questions, please contact your ERCOT Account Manager. You may also call the general ERCOT Client Services phone number at (512) 248-3900 or contact ERCOT Client Services via email at [email protected].

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