MMS Issues Review

1
MMS Issues Review

• Brandon Whittle
• Lead, Real-Time Market Operations

2
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?

3
Use of Combined Cycle Power Augmentation Methods

• Protocol 6.5.5.2 (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
• 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.

4
Use of Generic Incremental Cost for Energy
Dispatch in RUC

• Protocol 5.5.2 (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 4.4.9.4, 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 0.001.
• 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

5
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

6
Use of Telemetered Ramp Rate in Real-Time

• Protocols 6.4.5 (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 6.5.7.1.12
• (c) Normal Ramp Rate by using the curve submitted
  by the QSE and the Resources MW telemtery
• (d) Emergency Ramp Rate by using the curve
  submitted by the QSE and the Resources MW
  telemtery
• In Protocols 6.5.7.2, 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.

7
The End
Questions?