NOTICE DATE: November 7, 2024

NOTICE TYPE: M-A110724-01 Operations

SHORT DESCRIPTION: FINAL Geomagnetically Induced Current (GIC) flow results posted

INTENDED AUDIENCE: ERCOT Resource Entities (REs) and Transmission Service Providers (TSPs) and NERC-registered Transmission Owners and Generator Owners

DAYS AFFECTED: November 7, 2024

LONG DESCRIPTION: On October 4, 2024, ERCOT posted preliminary GIC flow results for the benchmark and supplemental GMD events as described in Market Notice M-B100424-01 Preliminary Geomagnetically Induced Current (GIC) flow results posted. ERCOT requested that TSPs and REs provide comments on the posted GIC flow results by October 18, 2024. ERCOT has addressed the comments received from TSPs and REs and posted the final GIC flow results.

Pursuant to paragraph (1) of Planning Guide Section 3.1.8, Planning Geomagnetic Disturbance (GMD) Activities, the final GIC flow results have been posted as a “GIC Transformer GIC Flow Information” report (EMIL ID PG3-953-M, Report ID 15633) on the Regional Planning page of the Market Information System (MIS) Secure Area. A Digital Certificate with the role ICE_M_VIEW_ECEII is required to access this ERCOT Critical Energy Infrastructure Information (ECEII) data.

Pursuant to paragraph (1)(e) of Planning Guide Section 6.11, Process for Developing Geomagnetically-Induced Current (GIC) System Models, supporting models are available to TSPs in the “GMD Planning Studies” reports (EMIL ID PG6-105-M, Report ID 14546) on the Transmission Service Provider Information page of the MIS Certified Area. A Digital Certificate with the ICE_M_VIEW_TOECEII role is required to access this Transmission Operator-only ECEII data.

In both locations, see files that include "Final_Transformer_GIC" in the file name.

ACTION REQUIRED: Pursuant to paragraph (2) of Planning Guide Section 3.1.8, ERCOT requests that affected TSPs and Resource Entities email their thermal impact assessment results and suggested actions to mitigate the impact of GICs, if applicable, to GMDVA@ercot.com with “Transformer Thermal Impact Assessment” in the subject line by May 7, 2026.

CONTACT: If you have any questions, please contact ERCOT Grid Planning via email at GMDVA@ercot.com.

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