ERCOT Adjusts Responsive Reserve Deployment Practice

On December 7, 2011, ERCOT will adjust the current Responsive Reserve Service (RRS) deployment practice, while still being in accordance with the ERCOT Protocols, ERCOT said in a market notice.

Currently, the ERCOT Energy Management System (EMS) 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.

Under the adjusted practice, to ensure that RRS capacity is requested and appropriately released during a potential NERC Disturbance Control Standard (DCS) event, 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).