Market Readiness for ERCOT Contingency Reserve Service - Key Milestones and Implementation

Weekly Market Readiness for ERCOT Contingency Reserve Service (ECRS) ERCOT staff May 16, 2023

Agenda 1. 2. 3. 4. 5. Key Milestones Key supporting documentation Qualification next steps Communication and Cutover Questions 2 PUBLIC

Milestones for ECRS Implementation ECRS Technical Specs- Sept 29, 2022 TWG meeting Market Readiness and Qualification Workshop (Monday April 3, 2023) Friday April 14, 2023- Deadline for Deadline for QSE Declaration of Resources Thursday, April 20, 2023- MOTE deployed for QSEs to test Tuesday, April 23, 2023- Begin Weekly Market Readiness WebEx meetings Current activity ECRS QSE qualification in-flight For all QSEs, scorecards begin for current MOTE activity June 6-8, 2023 Go-Live (first ECRS OD planned for June 10, 2023) 3 PUBLIC

Market Readiness for ECRS Key References (in April 13, 2023 Market Notice): ECRS Interface changes: https://www.ercot.com/calendar/09292022-TWG-Meeting-by-Webex ECRS Operations and Business explanation April 3, 2023 Workshop will be latest revisions- link to meeting Technical updates: Sample XML Questions XML Sample ECRS Deployment 03/29/2023 09.03.09 AM DEPLOY_MW: 5.0, BEGIN_TIME: 2023-03-29 09:03:09, END_TIME: 2023-03-29 10:00:00, DURATION: 56.85 mins, ID: 365; XML Sample ECRS DAM Award Sample DAM AS Awards place on April 3, 2023 Workshop link to meeting EIP specifications document has been updated here https://www.ercot.com/files/docs/2022/05/03/EIP-External- Interfaces-Specification-v1.25.zip Extract MODE/CODE details in Market Notice Friday May 5, 2023 Updated AS Methodology supporting deployment details Incorporated the ECRS deployment procedure into the updated AS Methodology documentation on the ERCOT website (ercot.com | Market Information | Day-Ahead Market | Methodology for Determining Minimum AS Reqt). Scorecards will begin publishing on May 9, 2023 (for activities of May 1-8) AS Offer submissions will be scored on ability to submit a single AS Offer into MOTE. COP submissions will be scored on ability to submit a single COP into MOTE. AS Self-Arrangement submissions will be scored on ability to submit an AS Self- Arrangement into MOTE. (see attached population of QSEs) QTEST CM-ASM-NOTF AS_TYPE: ECRS, RES_NAME: LD_TEST, 4 PUBLIC

Scorecard Details Important note, MOTE submissions should be OpDay + 2 days to avoid Credit errors in MOTE Scorecards on follow slides 5 PUBLIC

List/Snapshot of QSEs that historically submitted an AS Offer Jan 1 - Jan 31, 2023 Scorecard AS Offers Cumulative Score G R G R G G G G G R G R R R R R R R R R G R R R R R R G R G G G G G R R G R G G R R R G R R G G G G G G G G R R PARTICIPANT_NAME QAEN QALTRE QBEEP1 QBRAZP QBRD11 QBTU QCALP QCPSE QDENT2 QDUKER QECNR QEDE20 QEDE21 QEDES3 QEDF20 QEDF21 QEDF22 QEDF23 QEDF26 QEDF39 QEDIS9 QENDU2 QENEL5 QENEL6 QENROC QENRWI QEONG3 QEXELO QFPL12 QGAR QGAR14 QGEUS QLCRA QLUMN QMCADO QMP2EN QNGREN QNRGTX QOCCID QPERFT QPRIO1 QPRIOR QSCURY QSHEL2 QSTEC QSTEC3 QSUE23 QTEN20 QTEN22 QTEN23 QTEN25 QTENS4 QTENS7 QTENSK QTURKY QVOLTU MP_FULLNAME CITY OF AUSTIN DBA AUSTIN ENERGY (QSE) MP2 ENERGY TEXAS LLC DBA SHELL ENERGY SOLUTIONS (QSE) HEN POWER MARKETING LLC (SQ1) BRAZOS ELECTRIC POWER CO OP INC POST (QSE) BROAD REACH QSE I LLC (SQ1) BTU QSE SERVICES INC (QSE) CALPINE POWER MANAGEMENT LLC (QSE) CPS ENERGY (QSE) DENTON MUNICIPAL ELECTRIC (SQ2) DUKE ENERGY RENEWABLE SERVICES LLC (QSE) RWE RENEWABLES QSE LLC (QSE) EDF ENERGY SERVICES LLC (SQ20) EDF ENERGY SERVICES LLC (SQ21) EDF ENERGY SERVICES LLC (SQ3) EDF NORTH AMERICA (SQ20) EDF NORTH AMERICA (SQ21) EDF NORTH AMERICA (SQ22) EDF NORTH AMERICA (SQ23) EDF NORTH AMERICA (SQ26) EDF NORTH AMERICA (SQ39) BOSTON ENERGY TRADING AND MARKETING LLC (SQ9) ETC ENDURE ENERGY LLC LAAR (SQ2) ENEL TRADING NORTH AMERICA LLC (SQ5) ENEL TRADING NORTH AMERICA LLC (SQ6) ENEL X NORTH AMERICA INC (QSE) ENERWISE GLOBAL TECHNOLOGIES LLC (QSE) UNIPER GLOBAL COMMODITIES NORTH AMERICA LLC (SQ3) CONSTELLATION ENERGY GENERATION LLC (QSE) NEXTERA ENERGY MARKETING LLC (SQ12) CITY OF GARLAND (QSE) CITY OF GARLAND (SQ14) GEUS (QSE) LOWER COLORADO RIVER AUTHORITY (QSE) LUMINANT ENERGY COMPANY LLC (QSE) MCADOO WIND ENERGY LLC (QSE) MP2 ENERGY LLC (QSE) NG RENEWABLES ENERGY SERVICES LLC (QSE) NRG TEXAS POWER LLC (QSE) OCCIDENTAL POWER SERVICES INC (QSE) PERFECT POWER SOLUTIONS TEXAS LLC (QSE) PRIORITY POWER MANAGEMENT LLC (SQ1) PRIORITY POWER MANAGEMENT LLC (QSE) SCURRY COUNTY WIND LP (QSE) SHELL ENERGY NORTH AMERICA (US) LP (SQ2) SOUTH TEXAS ELECTRIC CO OP INC (QSE) SOUTH TEXAS ELECTRIC CO OP INC (SQ3) ENGIE ENERGY MARKETING NA INC (SQ23) TRQ20 (SQ20) TRQ22 (SQ22) TRQ23 (SQ23) TRQ25 (SQ25) TRQ4 (SQ4) TRQ7 (SQ7) TENASKA POWER SERVICES CO (QSE) TURKEY TRACK WIND ENERGY LLC (QSE) VOLTUS INC (QSE) Week 1 Week 2 Week 3 Week 4 G R G R G G G G G R R R R R R R R R R R G R R R R R R G R G G G G G R R G R G G R R R G R R G G G G G G G G R R G R G R G G G G G R G R R R R R R R R R G R R R R R R G R G G G G G R R G R G G R R R G R R G G G G G G G G R R - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6 PUBLIC

QEDF21 QEDF22 QEDF23 QEDF24 QEDF25 QEDF26 QEDF27 QEDF28 QEDF29 QEDF32 QEDF33 QEDF35 QEDF39 QEDF40 QEDF41 QEDF42 QEDF43 QEDF44 QEDIS4 QEDIS5 QEDIS7 QEDIS9 QEDISO QENDU2 QENE10 QENEL1 QENEL2 QENEL5 QENEL6 QENEL7 QENEL8 QENEL9 QENELT QENROC QENRWI QEONG3 QEONG4 QEONG6 QEONG7 QEONG8 QEXELO QFORMO QFPL10 QFPL11 QFPL12 QFPL14 QFPL17 QFPL18 QFPL20 QFPL23 QFPL24 QFPL25 QFPL26 QFPL28 QFPL29 QFPL30 QFPL31 QFPLE EDF NORTH AMERICA (SQ21) EDF NORTH AMERICA (SQ22) EDF NORTH AMERICA (SQ23) EDF NORTH AMERICA (SQ24) EDF NORTH AMERICA (SQ25) EDF NORTH AMERICA (SQ26) EDF NORTH AMERICA (SQ27) EDF NORTH AMERICA (SQ28) EDF NORTH AMERICA (SQ29) EDF NORTH AMERICA (SQ32) EDF NORTH AMERICA (SQ33) EDF NORTH AMERICA (SQ35) EDF NORTH AMERICA (SQ39) EDF NORTH AMERICA (SQ40) EDF NORTH AMERICA (SQ41) EDF NORTH AMERICA (SQ42) EDF NORTH AMERICA (SQ43) EDF NORTH AMERICA (SQ44) BOSTON ENERGY TRADING AND MARKETING LLC (SQ4) BOSTON ENERGY TRADING AND MARKETING LLC (SQ5) BOSTON ENERGY TRADING AND MARKETING LLC (SQ7) BOSTON ENERGY TRADING AND MARKETING LLC (SQ9) BOSTON ENERGY TRADING AND MARKETING LLC (QSE) ETC ENDURE ENERGY LLC LAAR (SQ2) ENEL TRADING NORTH AMERICA LLC (SQ10) ENEL TRADING NORTH AMERICA LLC (SQ1) ENEL TRADING NORTH AMERICA LLC (SQ2) ENEL TRADING NORTH AMERICA LLC (SQ5) ENEL TRADING NORTH AMERICA LLC (SQ6) ENEL TRADING NORTH AMERICA LLC (SQ7) ENEL TRADING NORTH AMERICA LLC (SQ8) ENEL TRADING NORTH AMERICA LLC (SQ9) ENEL TRADING NORTH AMERICA LLC (QSE) ENEL X NORTH AMERICA INC (QSE) ENERWISE GLOBAL TECHNOLOGIES LLC (QSE) UNIPER GLOBAL COMMODITIES NORTH AMERICA LLC (SQ3) UNIPER GLOBAL COMMODITIES NORTH AMERICA LLC (SQ4) UNIPER GLOBAL COMMODITIES NORTH AMERICA LLC (SQ6) UNIPER GLOBAL COMMODITIES NORTH AMERICA LLC (SQ7) UNIPER GLOBAL COMMODITIES NORTH AMERICA LLC (SQ8) CONSTELLATION ENERGY GENERATION LLC (QSE) FORMOSA UTILITY VENTURE LTD (QSE) NEXTERA ENERGY MARKETING LLC (SQ10) NEXTERA ENERGY MARKETING LLC (SQ11) NEXTERA ENERGY MARKETING LLC (SQ12) NEXTERA ENERGY MARKETING LLC (SQ14) NEXTERA ENERGY MARKETING LLC (SQ17) NEXTERA ENERGY MARKETING LLC (SQ18) NEXTERA ENERGY MARKETING LLC (SQ20) NEXTERA ENERGY MARKETING LLC (SQ23) NEXTERA ENERGY MARKETING LLC (SQ24) NEXTERA ENERGY MARKETING LLC (SQ25) NEXTERA ENERGY MARKETING LLC (SQ26) NEXTERA ENERGY MARKETING LLC (SQ28) NEXTERA ENERGY MARKETING LLC (SQ29) NEXTERA ENERGY MARKETING LLC (SQ30) NEXTERA ENERGY MARKETING LLC (SQ31) NEXTERA ENERGY MARKETING LLC (QSE) R R R R R R R R R R G R R R R G R R R R R G R R R R R R R R R R R R R R R R R R G R R R G R R R R R R R R R R R R R Scorecard COP part 1 List/Snapshot of QSEs that historically submitted a COP Jan 1 - Jan 31, 2023 Cumulative Score G G R G G G R G G G G R G G G R G R R R G G G G G G G R G G R R R R R R R R R R R R R R PARTICIPANT_NAME QAEN QAEPS3 QALTRE QAVAN3 QBEEP1 QBEEPO QBRAZP QBRD11 QBRZSC QBTU QBULL QCAL13 QCALP QCPSE QCPSE1 QDENT1 QDENT2 QDENT3 QDIR12 QDIR13 QDUKE1 QDUKE2 QDUKE3 QDUKE4 QDUKE5 QDUKE6 QDUKE7 QDUKE8 QDUKER QECNR QECNR2 QECNR4 QECNR5 QECNR6 QECNR7 QEDE12 QEDE20 QEDE21 QEDE34 QEDES3 QEDF15 QEDF16 QEDF17 QEDF20 MP_FULLNAME CITY OF AUSTIN DBA AUSTIN ENERGY (QSE) AMERICAN ELECTRIC POWER SERVICE CORP (SQ3) MP2 ENERGY TEXAS LLC DBA SHELL ENERGY SOLUTIONS (QSE) AVANGRID RENEWABLES LLC (SQ3) HEN POWER MARKETING LLC (SQ1) HEN POWER MARKETING LLC (QSE) BRAZOS ELECTRIC POWER CO OP INC POST (QSE) BROAD REACH QSE I LLC (SQ1) BRAZOS SANDY CREEK ELECTRIC COOPERATIVE INC (QSE) BTU QSE SERVICES INC (QSE) BULL CREEK WIND LLC (QSE) CALPINE POWER MANAGEMENT LLC (SQ13) CALPINE POWER MANAGEMENT LLC (QSE) CPS ENERGY (QSE) CPS ENERGY WIND (SQ1) DENTON MUNICIPAL ELECTRIC (SQ1) DENTON MUNICIPAL ELECTRIC (SQ2) DENTON MUNICIPAL ELECTRIC (SQ3) DIRECT ENERGY LP (SQ12) DIRECT ENERGY LP (SQ13) DUKE ENERGY RENEWABLE SERVICES LLC (SQ1) DUKE ENERGY RENEWABLE SERVICES LLC (SQ2) DUKE ENERGY RENEWABLE SERVICES LLC (SQ3) DUKE ENERGY RENEWABLE SERVICES LLC (SQ4) DUKE ENERGY RENEWABLE SERVICES LLC (SQ5) DUKE ENERGY RENEWABLE SERVICES LLC (SQ6) DUKE ENERGY RENEWABLE SERVICES LLC (SQ7) DUKE ENERGY RENEWABLE SERVICES LLC (SQ8) DUKE ENERGY RENEWABLE SERVICES LLC (QSE) RWE RENEWABLES QSE LLC (QSE) RWE RENEWABLES QSE LLC (SQ2) RWE RENEWABLES QSE LLC (SQ4) RWE RENEWABLES QSE LLC (SQ5) RWE RENEWABLES QSE LLC (SQ6) RWE RENEWABLES QSE LLC (SQ7) EDF ENERGY SERVICES LLC (SQ12) EDF ENERGY SERVICES LLC (SQ20) EDF ENERGY SERVICES LLC (SQ21) EDF ENERGY SERVICES LLC (SQ34) EDF ENERGY SERVICES LLC (SQ3) EDF TRADING (SQ15) EDF TRADING (SQ16) EDF TRADING (SQ17) EDF NORTH AMERICA (SQ20) 7 PUBLIC

QFPLE1 QFPLE2 QFPLE3 QFPLE6 QFPLE8 QGALT QGALT1 QGALT4 QGAR QGAR11 QGAR14 QGAR5 QGERD QGEUS QGOLD QGOLDN QGRIDB QGUNSI QIBER QIBER1 QIPLU2 QIPLUM QIPRAD QLCRA QLONE2 QLUMN QLUMN1 QM2SQ1 QMCADO QMIAMI QMITS2 QMP2E5 QMP2EN QNGREN QNRGT4 QNRGTX QOCCID QPATT1 QPATT2 QPATT3 QPERFT QPRIO1 QPRIO2 QPRIOR QRATTL QRAYBN QSAMEN QSAMSO QSANDY QSANTA QSANTE NEXTERA ENERGY MARKETING LLC (SQ1) NEXTERA ENERGY MARKETING LLC (SQ2) NEXTERA ENERGY MARKETING LLC (SQ3) NEXTERA ENERGY MARKETING LLC (SQ6) NEXTERA ENERGY MARKETING LLC (SQ8) GALT POWER INC (QSE) GALT POWER INC (SQ1) GALT POWER INC (SQ4) CITY OF GARLAND (QSE) CITY OF GARLAND (SQ11) CITY OF GARLAND (SQ14) CITY OF GARLAND (SQ5) GERDAU AMERISTEEL ENERGY INC (QSE) GEUS (QSE) GOLDTHWAITE WIND ENERGY LLC (QSE) GOLDEN SPREAD ELECTRIC COOPERATIVE INC (QSE) GRIDBEYOND LLC (QSE) GUNSIGHT MOUNTAIN WIND ENERGY LLC (QSE) AVANGRID RENEWABLES LLC (QSE) AVANGRID RENEWABLES LLC (SQ1) IP LUMINA II LLC (QSE) IP LUMINA LLC (QSE) IP RADIAN LLC (QSE) LOWER COLORADO RIVER AUTHORITY (QSE) MESQUITE GENERATION HOLDINGS LLC (QSE) LUMINANT ENERGY COMPANY LLC (QSE) LUMINANT ENERGY COMPANY LLC (SQ1) MP2 ENERGY LLC (SQ1) MCADOO WIND ENERGY LLC (QSE) MIAMI WIND I LLC (QSE) MITSUI AND CO ENERGY MARKETING AND SERVICES (USA) INC (SQ2) G MP2 ENERGY TEXAS LLC DBA SHELL ENERGY SOLUTIONS (SQ5) MP2 ENERGY LLC (QSE) NG RENEWABLES ENERGY SERVICES LLC (QSE) NRG TEXAS CEDAR BAYOU (SQ4) NRG TEXAS POWER LLC (QSE) OCCIDENTAL POWER SERVICES INC (QSE) PATTERN ENERGY MANAGEMENT SERVICES LLC (SQ1) PATTERN ENERGY MANAGEMENT SERVICES LLC (SQ2) PATTERN ENERGY MANAGEMENT SERVICES LLC (SQ3) PERFECT POWER SOLUTIONS TEXAS LLC (QSE) PRIORITY POWER MANAGEMENT LLC (SQ1) PRIORITY POWER MANAGEMENT LLC (SQ2) PRIORITY POWER MANAGEMENT LLC (QSE) RATTLESNAKE WIND I LLC (QSE) RAYBURN COUNTRY ELECTRIC COOPERATIVE INC (QSE) SAMSON SOLAR ENERGY III LLC (QSE) SAMSON SOLAR ENERGY LLC (QSE) SANDY CREEK ENERGY ASSOCIATES LP (QSE) SANTA RITA WIND ENERGY LLC (QSE) SANTA RITA EAST WIND ENERGY LLC (QSE) R R R R R R R R G R G R R G R R R R G G G G G G R G G R R R QSCUR2 QSCURY QSHEL1 QSHEL2 QSHEL7 QSTANT QSTEC QSTEC3 QSTEC4 QSUE10 QSUE11 QSUE15 QSUE16 QSUE17 QSUE18 QSUE19 QSUE20 QSUE23 QSUE24 QSUE30 QSUE35 QSUE37 QSUE41 QSUE42 QSUE47 QSUEZ8 QSUST QTEN10 QTEN14 QTEN15 QTEN16 QTEN17 QTEN20 QTEN21 QTEN22 QTEN23 QTEN25 QTENS4 QTENS7 QTENSK QTOTL2 QTOTL3 QTURKY QVOLTU QWAKE QWAKE2 SCURRY COUNTY WIND II LLC (QSE) SCURRY COUNTY WIND LP (QSE) SHELL ENERGY NORTH AMERICA (US) LP (SQ1) SHELL ENERGY NORTH AMERICA (US) LP (SQ2) SHELL ENERGY NORTH AMERICA (US) LP (SQ7) STANTON WIND ENERGY LLC (QSE) SOUTH TEXAS ELECTRIC CO OP INC (QSE) SOUTH TEXAS ELECTRIC CO OP INC (SQ3) SOUTH TEXAS ELECTRIC CO OP INC (SQ4) ENGIE ENERGY MARKETING NA INC (SQ10) ENGIE ENERGY MARKETING NA INC (SQ11) ENGIE ENERGY MARKETING NA INC (SQ15) ENGIE ENERGY MARKETING NA INC (SQ16) ENGIE ENERGY MARKETING NA INC (SQ17) ENGIE ENERGY MARKETING NA INC (SQ18) ENGIE ENERGY MARKETING NA INC (SQ19) ENGIE ENERGY MARKETING NA INC (SQ20) ENGIE ENERGY MARKETING NA INC (SQ23) ENGIE ENERGY MARKETING NA INC (SQ24) ENGIE ENERGY MARKETING NA INC (SQ30) ENGIE ENERGY MARKETING NA INC (SQ35) ENGIE ENERGY MARKETING NA INC (SQ37) ENGIE ENERGY MARKETING NA INC (SQ41) ENGIE ENERGY MARKETING NA INC (SQ42) ENGIE ENERGY MARKETING NA INC (SQ47) ENGIE ENERGY MARKETING NA INC (SQ8) SUSTAINING POWER SOLUTIONS LLC (QSE) TRQ10 (SQ10) TRQ14 (SQ14) TRQ15 (SQ15) TRQ16 (SQ16) TRQ17 (SQ17) TRQ20 (SQ20) TRQ21 (SQ21) TRQ22 (SQ22) TRQ23 (SQ23) TRQ25 (SQ25) TRQ4 (SQ4) TRQ7 (SQ7) TENASKA POWER SERVICES CO (QSE) TOTALENERGIES GAS AND POWER NORTH AMERICA INC (SQ2) TOTALENERGIES GAS AND POWER NORTH AMERICA INC (SQ3) TURKEY TRACK WIND ENERGY LLC (QSE) VOLTUS INC (QSE) WAKE WIND ENERGY LLC (QSE) WAKE WIND ENERGY LLC 2 (SQ1) R R R G R R R R R R R R R R R R R G R R R R R R R R R G G G G G G G G G G G G G G G R R G G COP part 2 R R G R R G R R R G G R R R R R R G R R 8 PUBLIC

List/Snapshot of QSEs that historically submitted Self AS Jan 1 - Jan 31, 2023 Scorecard AS Self- Arrangement Cumulative Score R R R R G G G R R R R R R R R R R R R R R R R R R R G R R R R G R R R R G R R R G G R R PARTICIPANT_NAME QACCEN QAEN QALTRE QBPEC7 QBTU QCALP QCPSE QEDE10 QEDE12 QEDES1 QEDES2 QEDES5 QEDES6 QEDES8 QEDF7 QEXEL1 QFREE1 QFRONT QGAR6 QGERD QGEXA QGEXA7 QGOLDN QJUSL1 QJUSL2 QJUSL3 QLCRA QMP2E3 QMP2E6 QNEWBR QNRGTX QOCSQ1 QRAYBN QSEMES QSHE14 QSHEL9 QSHELL QSTEC QSTEC1 QSUEZ1 QTEN18 QTENSK QTEXPO QTOTL1 MP_FULLNAME ACCENT ENERGY TEXAS LP (QSE) CITY OF AUSTIN DBA AUSTIN ENERGY (QSE) MP2 ENERGY TEXAS LLC DBA SHELL ENERGY SOLUTIONS (QSE) BPTX (SQ7) BTU QSE SERVICES INC (QSE) CALPINE POWER MANAGEMENT LLC (QSE) CPS ENERGY (QSE) EDF ENERGY SERVICES LLC (SQ10) EDF ENERGY SERVICES LLC (SQ12) EDF ENERGY SERVICES LLC (SQ1) EDF ENERGY SERVICES LLC (SQ2) EDF ENERGY SERVICES LLC (SQ5) EDF ENERGY SERVICES LLC (SQ6) EDF ENERGY SERVICES LLC (SQ8) EDF TRADING (SQ7) CONSTELLATION ENERGY GENERATION LLC (SQ1) FREEPOINT COMMODITIES LLC SOLUTIONS (SQ1) FRONTIER UTILITIES LLC (QSE) CITY OF GARLAND (SQ6) GERDAU AMERISTEEL ENERGY INC (QSE) GEXA ENERGY LP (QSE) GEXA ENERGY LP (SQ7) GOLDEN SPREAD ELECTRIC COOPERATIVE INC (QSE) JUST ENERGY LIMITED (SQ1) JUST ENERGY LIMITED (SQ2) JUST ENERGY LIMITED (SQ3) LOWER COLORADO RIVER AUTHORITY (QSE) MP2 ENERGY TEXAS LLC DBA SHELL ENERGY SOLUTIONS (SQ3) MP2 ENERGY TEXAS LLC DBA SHELL ENERGY SOLUTIONS (SQ6) NEW BRAUNFELS UTILITIES (QSE) NRG TEXAS POWER LLC (QSE) OCCIDENTAL POWER SERVICES INC (SQ1) RAYBURN COUNTRY ELECTRIC COOPERATIVE INC (QSE) CALPINE ENERGY SOLUTIONS LLC (QSE) SHELL ENERGY NORTH AMERICA (US) LP (SQ14) SHELL ENERGY NORTH AMERICA (US) LP (SQ9) SHELL ENERGY NORTH AMERICA (US) LP (QSE) SOUTH TEXAS ELECTRIC CO OP INC (QSE) NUECES ELECTRIC COOPERATIVE INC RETAIL DIVISION (SQ1) ENGIE ENERGY MARKETING NA INC (SQ1) TRQ18 (SQ18) TENASKA POWER SERVICES CO (QSE) TEXPO POWER LP DBA TEXPO ENERGY (QSE) TOTALENERGIES GAS AND POWER NORTH AMERICA INC (SQ1) Week 1 Week 2 Week 3 Week 4 R R R R G G G R R R R R R R R R R R R R R R R R R R G R R R R G R R R R G R R R G G R R R R R R G G G R R R R R R R R R R R R R R R R R R R G R R R R G R R R R G R R R G G R R - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 9 PUBLIC

Qualification and Telemetry for ECRS ERCOT s ICCP handbook was updated to include the various telemetry changes that are being put in place to support implementation of ECRS. ERCOT is proceeding through Qualification Requests on a first-in-first-out basis Telemetry should have been requested by end of week (4/28), but if not then sooner is better. If telemetry is not requested and ready, ERCOT will move to next QSE Follow normal processes for requesting new ICCP Service Request. Additional support from ercoticcpsupport@ercot.com 10 PUBLIC

Communication and Cutover Please send all communication through ERCOT Client Services to ensure it is assigned and addressed (ClientServices@ercot.com). MOTE questions will go to IT group Qualification questions for Gen-side will go to Operations Qualification questions for Load resource will go to Demand-side Details of ECRS will go to Operations and/or MarketDesign teams 11 PUBLIC

Communication and Cutover June 8, 2023 o System upgrade will occur the afternoon of June 8th between 3:30-4:00pm o MPs do not need to take any immediate action following the upgrade. o After the upgrade ECRS system functionality will be available for OD June 10, 2023 Note that COP, AS Trades, AS Offers, Self-Arranged AS must only be submitted for OD June 10 or later (not systematically enforced) - June 9, 2023 o Starting at 12:01am Telemetry for On-Hold status can be used (NPRR1085) o Day-Ahead Market activities include ECRS: o AS Plan published for DAM OD June 10 will include ECRS values for DAM consideration o QSEs submit AS Self Arrangements and AS Offers into DAM o DAM Awards for OD June 10 will include ECRS Awards and should be reflected in COP for OD June 10 for DRUC run. o After DAM, QSE submits COP updates OD June 10 to include ECRS - June 10, 2023 o First Operating Day with ECRS o Starting at 12:01am, telemetry should include ECRS values - 12 PUBLIC

Wrap-up and Questions Questions from last week: Question regarding details for XSD for Current Day reports: Answer: Posting is here: https://www.ercot.com/files/docs/2023/03/31/Current-Day-Reports_XSD_2023-R3-ECRS-DRAFT.txt Question: Can you please advise if ERCOT xsd will be updated so that users can submit a null value for ECRSM via API ? Currently, the XSD does not allow null value to be submitted for ECRSM. The following error message was received when we tested it. Users are allowed to null out the value in MOTE however, API does not allow an ECRSM tag with a null value. Answer: The XSD does not allow null value for <ecrsm_value>. This element is not required in the submission. Wrap-Up: For ECRS QSE qualification in-flight For all QSEs, scorecards continue for current MOTE activity this week May 15 to be reported at next meeting Cumulative, one-and-done scoring on this, not a weekly activity Market cutover discussion next week Open to any and all questions? You can also contact Matt.Mereness@ercot.com 13 PUBLIC