NOTICE DATE: October 22, 2021

NOTICE TYPE: W-A102221-01 Operations

SHORT DESCRIPTION: Update to forecast variability process beginning November 1, 2021

INTENDED AUDIENCE: ERCOT Market Participants

DAYS AFFECTED: November 1, 2021 onwards

LONG DESCRIPTION: Beginning with Operating Day November 1, 2021, ERCOT will update the forecast variability process. Specifically, ERCOT will determine any increase in Non-Spin requirement for Operating Day hours that have an increased potential for high forecast variability by close of business (COB) two days in advance. Additionally, ERCOT will post the updated Non-Spin quantities in the DAM Ancillary Service Plan (EMIL ID NP4-33-CD | Report Type ID 12316) report created one day in advance of the Operating Day. For example, for Operating Day November 1, 2021, ERCOT will determine any increase in Non-Spin quantities for hours with a potential for high forecast variability by close of business on October 30, 2021. ERCOT will post any update to the Non-Spin quantities in the DAM Ancillary Service Plan (EMIL ID NP4-33-CD | Report Type ID 12316) report for Operating Day November 1, 2021 that is posted the morning of October 31, 2021. (Typical posting time is around 5:00 am).

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 ClientServices@ercot.com.

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