NOTICE DATE:  November 30, 2011

NOTICE TYPE:  W-B113011-01 Operations

SHORT DESCRIPTION:  Change in RRS deployment practice

INTENDED AUDIENCE:  QSEs with Resources

DAY AFFECTED:  December 7, 2011

LONG DESCRIPTION:  Responsive Reserve (RRS) is a service used to restore or maintain the frequency of the ERCOT System in response to, or to prevent, significant frequency deviations. The ERCOT Energy Management System (EMS) currently calculates how much RRS is needed based on the change in frequency and the ERCOT Frequency Bias. This amount is then compared to Regulation-Up service remaining, as well as the generation capacity available between the ERCOT-wide High Dispatch Limit (HDL) and the total On-Line generation capacity. If required, then an electronic signal is sent to release the RRS capacity.

On December 7, 2011, ERCOT will adjust the current RRS deployment practice, while still being in accordance with the ERCOT Protocols. Under the adjusted practice, to ensure that RRS capacity is requested and appropriately released during a potential NERC Disturbance Control Standard (DCS) event (for more information see NERC BAL-002 Standard), ERCOT will only compare the calculated RRS against the available Regulation-Up service. The calculated RRS will also have a tunable constant which will be seasonally adjusted to accurately reflect the RRS required for recovering frequency disturbance. The change will ensure that the required amount of RRS capacity is requested at the necessary times (via telemetry) by the ERCOT EMS. In turn, the RRS capacity can be released by the Ancillary Service providers and made available to Security-Constrained Economic Dispatch (SCED).

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 [log in to unmask]<mailto:[log in to unmask]>.

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dh




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