7 August, 2006 TPTF MMS Issues Review Brandon Whittle Lead, Real-Time Market Operations

TPTF7 August, 2006 Notification of Mitigation in SCED If SCED issues a base point based on a mitigated offer, is there a requirement that QSEs be notified? –If not, is it something to add as a nice-to-have?

TPTF7 August, 2006 Use of Combined Cycle Power Augmentation Methods Protocol (9) –A QSE representing combined-cycle Resources shall provide ERCOT with the possible operating configurations for each power block with accompanying limits and price points. Power augmentation methods must be made available to ERCOT as part of one or more of the configurations. Price points for the range of the curve represented by the power augmentation method must reflect the price of the added capability. Such power augmentation methods may include: (a)Combustion turbine inlet air cooling (CTIAC) methods; (b)Duct firing; (c)Other ways of temporarily increasing the output of combined-cycle Resources; and (d)For QFs, an LSL that represents the minimum energy available, in MW, from the Resource for economic dispatch based on the minimum stable steam delivery to the thermal host plus a justifiable reliability margin that accounts for changes in ambient conditions. Assumption is that this is instructing QSEs to include these methods when considering their configuration limits and bids and ERCOT does provide any specific type of dispatch or commitment to account for these methods.

TPTF7 August, 2006 Use of Generic Incremental Cost for Energy Dispatch in RUC Protocol (4) –To determine the projected energy output level of each Resource and to project potential congestion patterns for each hour of the RUC, ERCOT shall calculate proxy Energy Offer Curves based on the Mitigated Offer Caps for the type of Resource as specified in Section , Mitigated Offer Cap and Mitigated Offer Floor, for use in the RUC. Proxy Energy Offer Curves are calculated by multiplying the Mitigated Offer Cap by a constant selected by ERCOT from time to time and applying the cost for all Generation Resource output between HSL and LSL. The constant selected by ERCOT may not be more than Multiplying offers by a small constant (.001) will prevent offers from influencing commitment ERCOT is concerned that using Mitigated Caps instead of available Offers will produce a inaccurate dispatch prediction within RUC leading to a different set of transmission constraints than would be present in SCED

TPTF7 August, 2006 Energy Offer Curves for RUC Committed Units Is a QSE required to submit an Energy Offer Curve for a RUC committed unit? –If Yes: This would be consistent with Zonal Protocols Would allow Settlement Calculations to be simpler Needs to be in Protocols –If No: RUC calculation depends on Energy Offer Curve (through RTAIEC) Using Proxy Curves developed around Output Schedule leads to times when it is financially rewarding for QSEs to not enter offer curve

TPTF7 August, 2006 Use of Telemetered Ramp Rate in Real-Time Protocols (1) –ERCOT shall use the telemetered Resource Status for all applications requiring status of Resources during the Operating Hour, including SCED, Load Frequency Control (LFC), and Network Security Analysis processes. QSEs shall provide ERCOT with accurate telemetry of the current capability of each Resource including the Resource Status, Ramp Rates, HSL, and LSL and a text reason for any Resource where a Ramp Rate is deviating from a standard Ramp Rate curve for the Resource, or the HSL is less than, or LSL is greater than, the normal high and low limits set in Section 3.7.1, Resource Parameter Criteria. Protocols –(c) Normal Ramp Rate by using the curve submitted by the QSE and the Resource’s MW telemtery; –(d) Emergency Ramp Rate by using the curve submitted by the QSE and the Resource’s MW telemtery; In Protocols , SCED ramp rates are calculated using normal and emergency ramp rates. What then, is the purpose of having a telemetered ramp rate? –ERCOT believes that using a telemetered ramp rate in SCED would be preferable since generation characteristics can change without timely update to registration data. –Use of telemetered ramp rates in SCED would require protocol changes.

TPTF7 August, 2006 Questions? The End