NOTICE DATE: April 15, 2011
NOTICE TYPE: M-A041511-01 NPRR
SHORT DESCRIPTION: Implementation details of NPRR285, Generation Resource Base Point Deviation Charge Corrections
INTENDED AUDIENCE: QSEs and QSE Settlement Personnel
DAY AFFECTED: May 18, 2011
LONG DESCRIPTION: The implementation of Nodal Protocol Revision Request (NPRR) 285 will provide a Curtailment Flag to Intermittent Renewable Resources (IRRs).
The following changes from the NPRR285 description are being implemented at ERCOT:
A flag will be sent by ERCOT to the Qualified Scheduling Entity (QSE) for each Resource indicating Security-Constrained Economic Dispatch (SCED) has dispatched a Generation Resource below the High Dispatch Limit (HDL) used by SCED.
A new settlements bill determinant, SBPBHDLFLAG (“SCED Base Point below HDL Flag”), will be created for this purpose. This bill determinant will be used by the settlement system to determine when the IRR Generation Resource Base Point Deviation Charge will apply. Additionally, two new pricing factors, PR1 and PR2, will be used by the settlement system in the Base Point Deviation calculations to modify how negative prices are considered in the penalty.
The following changes from the NPRR description are requested to be implemented in the relevant QSE systems:
Section 6.5.7.9(7), Compliance with Dispatch Instructions:
An Intermittent Renewable Resource (IRR) must comply with dispatch instructions when receiving a flag signifying that the IRR has received a Base Point below the HDL used by SCED.
The Curtailment Flag will be provided through Inter-Control Center Communications Protocol (ICCP) for all Resources. However, NPRR285 only requires IRR Generation Resources to take this flag into consideration.
QSEs may contact the ERCOT ICCP team at [log in to unmask] to obtain specific Object Names for their system implementation. The ICCP Handbook has been updated with the Curtailment Flag Object Name example and will be published following the ERCOT approval process.
Section 6.6.5.1.1(2), Base Point Deviation Charge for Over Generation:
The charge to each QSE for over-generation of each Generation Resource at each Resource Node Settlement Point, if the Real-Time metered generation is greater than the upper tolerance during a given 15-minute Settlement Interval, is calculated as follows:
BPDAMT q, r, p = Max (PR1, RTSPP p) * Max [0, (TWTG q, r, p – ¼ * Max (((1 + K1) * AABP q, r, p), (AABP q, r, p + Q1)))]
The Base Point Deviation Charge for Over Generation was modified to consider the new PR1 value to set a floor price when assessing the penalty.
Section 6.6.5.1.2(2), Base Point Deviation Charge for Under Generation:
The charge to each QSE for under-generation of each Generation Resource at each Resource Node Settlement Point for a given 15-minute Settlement Interval is calculated as follows:
BPDAMT q, r, p = (-1) * Min (PR2, RTSPP p) * Min (1, KP) * Max {0, {Min [((1 – K2) * ¼(AABP q, r, p)), ¼(AABP q, r, p – Q2)] – TWTG q, r, p}}
The Base Point Deviation Charge for Under Generation was modified to consider the new PR2 value to set a floor for the penalty.
New Settlement Bill Determinants:
The following new bill determinants will be implemented for NPRR285:
Bill Determinant | UOM | Description | Extract | Extract Table |
PR1 | $/MWh | The minimum price to use for the charge calculation when RTSPP is positive, $20. | PRDE | FACTOR FACTORVALUE |
PR2 | $/MWh | The minimum price to use for the charge calculation when RTSPP is negative, $-20. | PRDE | FACTOR FACTORVALUE |
SBPBHDLFLAG | Misc | Flag to indicate the condition of an IRR dispatched below HDL, i.e., the IRR was curtailed. The flag contains a value for each 15-minute interval. Format: SBPBHDLFLAG_<Q>_<R>_<SP> Value Set: 1 = The IRR was curtailed in all SCEDs within the 15-minute settlement interval. 0 = The IRR was not curtailed for all SCEDs within the 15-minute settlement interval. Application: If the SBPBHDLFLAG value = 1 in a 15-minute interval, the IRR will be subject to Base Point Deviation penalties in that interval. | SID RTM CODE | MKTINPUTHEADER MKTINPUTINTERVAL |
There are no changes to existing bill determinants.
ACTION REQUIRED: Implement the ICCP changes to receive the Curtailment Flag and make system changes to follow ERCOT dispatch instructions when the Curtailment Flag is set for IRRs. Implement changes to shadow settlement systems in compliance with NPRR285 grey box settlement language.
ADDITIONAL INFORMATION: A reminder Market Notice will be sent to all QSEs ten days prior to the actual ERCOT production migration, which is planned for May 18, 2011.
All IRRs will continue to receive exemption from Base Point Deviation penalties during a transition period effective upon implementation of the IRR Curtailment Flag and expiring at the end of Operating Day May 31, 2011.
All settlement changes required by NPRR285, and described above, will become effective on Operating Day June 1, 2011.
Even though the Base Point Deviation settlement will not use SBPBHDLFLAG prior to June 1, 2011, the flag data will be available and will be published in the Settlement Inputs Data (SID) Extract for all Operating Days beginning May 18, 2011.
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].
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