NOTICE DATE: October 31, 2014 NOTICE TYPE: W-B103114-01 Operations SHORT DESCRIPTION: Some Real-Time Settlement Point Prices for Operating Days October 6, 2014, through October 17, 2014 were incorrect due to a system error INTENDED AUDIENCE: All Market Participants DAY AFFECTED: Operating Days October 6, 2014 - October 17, 2014 LONG DESCRIPTION: ERCOT has identified an issue related to the recent implementation of Nodal Protocol Revision Request (NPRR) 485, Clarification for Fuel Adder Provisions. The fuel adder for Resources having Verifiable Costs was scheduled to take effect on 10/06/2014 00:00. However, the fuel adder used in the Mitigated Offer Curve (MOC) was incorrectly set to zero for all Resources having Verifiable Costs due to a system error from 10/06/2014 00:00 to 10/17/2014 15:00. This issue has been fixed for all the SCED intervals after 10/17/2014 15:00. During the affected timeframe, the MOC for Resources having Verifiable Costs was reduced since the fuel adder was set to 0. In turn, this issue has impacted Real-Time prices including Real-Time LMPs (RTLMPs) and Real-Time Settlement Point Prices (RTSPPs) during the affected timeframe. On October 21, 2014, ERCOT posted a notice to the Market Information System (MIS) public area indicating that this issue was under investigation. ERCOT has finished a preliminary impact assessment for this system error. The impact assessment shows that this system error resulted in incorrect RTSPPs for many Settlement Intervals for Operating Days October 6, 2014 to October 13, 2014 and October 17, 2014 (see the table below for a summary). Operating Days October 14, 2014 to October 16, 2014 were not impacted by this system error. Pursuant to paragraph 6 of Protocol Section 6.3, Adjustment Period and Real-Time Operations Timeline, the RTLMPs and RTSPPs for these Settlement Intervals are final. However, ERCOT has determined that the prices are in need of correction and therefore will recommend that the ERCOT Board of Directors (ERCOT Board) approve price corrections for certain RTLMPs and RTSPPs for Settlement Intervals covering the above referenced period. No change was required in the values of the Operating Reserve Demand Curve (ORDC) components (RTORPA and RTOFFPA). ADDITIONAL INFORMATION: ERCOT will place this price correction request as an agenda item at the December 9, 2014 ERCOT Board meeting. Board materials, including a detailed analysis, regarding the price correction request will be distributed in accordance with the Board Policies and Procedures. 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]>. If you are receiving email from an ERCOT distribution list that you no longer wish to receive, please follow this link in order to unsubscribe from this list: http://lists.ercot.com. RTSPPs Change Summary OPERATING_DAY INT_COUNT RTSPP_COUNT RN_COUNT HUB_COUNT LZ_COUNT RN_DIFF_RANGE [MIN,MAX] ($/MWh) HUB_DIFF_RANGE [MIN,MAX] ($/MWh) LZ_DIFF_RANGE [MIN,MAX] ($/MWh) RN_AVGABSDIFF ($/MWh) HUB_AVGABSDIFF ($/MWh) LZ_AVGABSDIFF ($/MWh) 10/6/2014 3 141 65 0 4 [-0.26,3.13] [0,0] [0.01,0.37] 0.31 0.00 0.17 10/7/2014 6 2876 564 6 13 [-0.33,1.25] [-0.06,0.23] [-0.08,0.35] 0.09 0.09 0.10 10/8/2014 4 472 343 4 8 [-0.31,3.76] [0.01,0.01] [0.01,0.45] 0.12 0.01 0.12 10/9/2014 7 3673 565 6 13 [-2.85,22.57] [-0.11,7.17] [-0.15,7.16] 2.38 2.21 2.18 10/10/2014 3 651 565 6 13 [-0.35,3.44] [0.09,0.11] [0.01,0.5] 0.16 0.10 0.18 10/11/2014 6 146 24 0 3 [-0.05,4.3] [0,0] [0.01,0.47] 0.77 0.00 0.19 10/12/2014 6 1076 565 6 13 [-0.46,4.39] [-0.02,-0.01] [-0.02,0.54] 0.09 0.02 0.11 10/13/2014 5 1807 558 6 13 [-0.31,2.98] [-0.06,-0.01] [-0.07,0.32] 0.07 0.03 0.07 10/17/2014 30 14025 565 6 13 [-1.39,33.61] [-0.67,0.18] [-0.11,11.96] 0.50 0.13 0.80 TOTAL 70 24867 565 6 13 [-2.85,33.61] [-0.67,0.7.17] [-0.15,11.96] 0.67 0.40 0.76 Legend INT_COUNT Unique count of affected 15-minute Settlement Intervals RTSPP_COUNT Count of affected Real-Time Settlement Point Prices RN_COUNT Unique count of affected Resource Nodes HUB_COUNT Unique count of affected Hubs LZ_COUNT Unique count of affected Load Zones RN_DIFF_RANGE Range of price difference (corrected - original) for affected Resource Nodes HUB_DIFF_RANGE Range of price difference (corrected - original) for affected Hubs LZ_DIFF_RANGE Range of price difference (corrected - original) for affected Load Zones RN_AVGABSDIFF Average absolute price difference (ABS (corrected - original)) for affected Resource Nodes HUB_AVGABSDIFF Average absolute price difference (ABS (corrected - original)) for affected Hubs LZ_AVGABSDIFF Average absolute price difference (ABS (corrected - original)) for affected Load Zones mm