NOTICE DATE:  June 26, 2015
NOTICE TYPE:  W-B062615-01 Settlements
SHORT DESCRIPTION:  Real-Time price corrections
INTENDED AUDIENCE:  QSE and CRRAH Settlement Personnel
DAY AFFECTED:  June 1, 2015 - June 25, 2015
LONG DESCRIPTION:  ERCOT has identified a need to correct the mean and standard deviation for the Loss of Load Probability distributions (LOLP) used in the Operating Reserve Demand Curve (ORDC), beginning June 1, 2015.  The correction affects ORDC price adders for less than 15% of the Security-Constrained Economic Dispatch (SCED) intervals from Operating Day June 1, 2015 through Operating Day June 25, 2015.  The estimated impact on the Real-Time On-Line Reserve Price Adder (RTORPA) ranges from $-1.81/MWh to $4.10/MWh, with a weighted average price change of about $-0.04/MWh.
The correction was implemented for the SCED runs starting from Operating Day June 25, 2015, hour 17:00.  ERCOT will correct the affected Real-Time prices for Operating Days June 24, 2015 and June 25, 2015 within the established timeframe for price corrections (See Protocol Section 6.3). The price correction for Operating Day June 24, 2015, will be posted by 16:00 of June 26, 2015, and the price correction for Operating Day June 25, 2015, will be posted by 16:00 of June 29, 2015.

For impacted intervals affecting Operating Days June 1, 2015 through June 23, 2015, ERCOT will seek Board of Directors review of such prices at its August 11, 2015 meeting (See Protocol Section 6.3(6)(a)).  ERCOT will recommend price corrections for the following:


  *   Real-Time On-Line Reserve Price Adder (RTORPA)
  *   Real-Time Off-Line Reserve Price Adder (RTOFFPA)
  *   Real-Time Reserve Price for On-Line Reserves (RTRSVPOR)
  *   Real-Time Reserve Price for Off-Line Reserves (RTRSVPOFF)
  *   Real-Time Settlement Point Prices (RTSPP)
  *   Real-Time Settlement Point Price Energy-Weighted (RTSPPEW)

*         EPS Meter Prices (RTRMPR)
The data issue was discovered in the mean and standard deviations posting which is effective through February 2016.  ERCOT will update this posting today, June 26, 2015.
ADDITIONAL INFORMATION:    The corrected Settlement Point Prices will be posted in both CSV and XML formats in the RTM Price Corrections folder located at http://www.ercot.com/mktinfo/prices/.
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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