1. Market Readiness Seminar Update Nodal Cutover Update July 28, 2010 Market Readiness Seminar #5

2. 2 Nodal Cutover and Market Transition Agenda Key Cutover Milestones Major Cutover Activities – 4 Month Lookout Cutover Communications Method Discussion 7/28/2010Market Readiness Seminar #5

3. 3 Nodal Cut-Over and Market Transition Topics That Will Be Covered Today  Key Cutover Dates - 4 Month Look Out (NMMS, CRR, OS, Credit, S&B, MMS)  High-Level Timeline  Cutover Communication Method  Upcoming Events Topics That Will Not Be Covered Today Beyond 4 Month Look Out (details) Post Go-Live Activities Contingency Plans System Decommissioning/Retirement Plans 7/28/2010Market Readiness Seminar #5

4. 4 2/5/2016 Cut-Over Milestones 7/28/2010Market Readiness Seminar #5

5. 5 Nodal Cutover and Market Transition – Key Cut-Over Milestones Key Cut-Over Milestones Network Model Nodal Protocol Section 3.10 goes into effect (Sept. 1) TAC Approval – July 1 (July 20) Board Approval – July 20 Market Notice – July 30 Congestion Revenue Rights Nodal Protocol Section 7 goes into effect (Oct. 13) TAC Approval – August 5 Board Approval – August 17 Market Notice – September 13 Outage Scheduler Nodal Protocol Section 3.1 goes into effect (Nov. 1) TAC Approval – August 5 Board Approval – August 17 Market Notice – October 1 Full Nodal Operations Nodal Protocol Sections 3, 4, 5 and 6 go into effect as well as all other unimplemented Protocol Sections (Nov. 23) TAC Approval – October 7 th Board Approval – October 19 th Market Notice – October 23 rd 7/28/2010Market Readiness Seminar #5

6. 6 2/5/2016 Key Cutover Activities 4 Month Look Out 7/28/2010Market Readiness Seminar #5

7. 7 Cut-Over Timeline – 4 Month Look Out 7/28/2010Market Readiness Seminar #5 4 Month Lookout

8. 8 Functional Area Task Plan Data Prep Decommission/Retirement Template Contingency/Back-out Template MayJuneJulyAugSeptOctNovDec Cut-Over Monthly Outlook – August Key Cut-Over Activities for August 2010 (08/01) Model: Begin network modeling timelines (08/13) OS: Outage Scheduler Zonal to Nodal Import process run (08/13) CRR: Last day to register for CRR December monthly auction (08/16) OS: ERCOT releases Outage Scheduler to Market (08/16-09/17) OS: Market Participants synchronize / verify outages in the Nodal Outage Scheduler to the Zonal Outage Scheduler for Outages effective during and after December 2010 Network Model Outage Scheduler Congestion Revenue Rights Entities Involved  ERCOT  TSP  REs  CRRAH  QSE Impacts TSPs/REs submit Transmission and Resource data for December model (05_Nodal_Load_transition_1_0.doc posted on 06/01 NATF Materials) Resource outages will NOT be imported during Zonal to Nodal import into Outage Scheduler CRRAH must register by deadline to be eligible to participate in the December Auction (Protocol 16.8.2) TSPs/QSEs can begin entering outages in Outage Scheduler via Web Service or UI TSPs/QSEs are responsible for verifying outages imported to Nodal Systems and correcting any missed outages or incorrect outages by 09/17/2010 Functional Area 7/28/2010Market Readiness Seminar #5

9. 9 Key Cut-Over Activities for September 2010 (09/01) Model: Network Model Go-Live (09/01) Model: Deadline to submit Model changes for Month of December (09/02) Model: Begin interim update process (09/13) CRR: ERCOT publishes CRR Activity Calendar to MIS (09/17-12/01) OS: Outages are synched. Market Participants maintain outages in both the Zonal and Nodal Outage Scheduler for outages effective December and beyond. Network Model Outage Scheduler Congestion Revenue Rights Functional Area MayJuneJulyAugSeptOctNovDec Cut-Over Monthly Outlook – September Entities Involved  ERCOT  TSP  REs  CRRAH  QSE Impacts TSPs / REs that submit Model changes to ERCOT by 09/01 will be applied prior to Go-Live From 09/02 forward until Go-Live any Model changes submitted to ERCOT for application prior to Go-Live will leverage the interim update process. MPs can retrieve the CRR Activity Calendar from MIS public with a valid Digital Certificate 7/28/2010Market Readiness Seminar #5

10. 10 Impacts MIS unavailable from 10/03-10/11 for production reconfiguration** CRRAH able to retrieve ACLs from CRR system each business day. MPs can post additional collateral until 11/08/2010 for Dec 2010 CRR Auction MPs able to start retrieving Go-Live postings on MIS. Refer to EMIL for dates per posting. More information in August workshop Dec 2010 CRR Model available on MIS Dec 2010 Monthly Auction Notice available on MIS Functional Area Network Model Outage Scheduler Congestion Revenue Rights Credit MayJuneJulyAugSeptOctNovDec Cut-Over Monthly Outlook – October Key Cut-Over Activities for October 2010 (10/01) CRR: CRR system data clean up for Go-Live (10/01) Credit: ERCOT assesses each CPs credit worthiness for the Dec CRR Auction (10/02) OS: First pull of December Outages for CRR Network Model (10/02) Model: Network Model built for PCRR Allocation (10/03-10/11) MIS: ERCOT PERFORMS PRODUCTION RECONFIGURATIONS ON MIS** (10/13) OS: December Outages pulled for CRR Auction Model (10/13) Model: Model built for CRR December Auction 7/28/2010Market Readiness Seminar #5

11. 11 Impacts MIS unavailable from 10/03-10/12 for production reconfiguration CRRAH able to retrieve ACLs from CRR system each business day. MPs can post additional collateral until 11/08/2010 for Dec 2010 CRR Auction MPs able to start retrieving Go-Live postings on MIS. Refer to EMIL for dates per posting. More information in August workshop Dec 2010 CRR Model available on MIS Dec 2010 Monthly Auction Notice available on MIS Functional Area Network Model Outage Scheduler Congestion Revenue Rights Credit MayJuneJulyAugSeptOctNovDec Cut-Over Monthly Outlook – October Key Cut-Over Activities for October 2010 (10/13-10/18) CRR: ERCOT begins accepting PCRR Nominations for December Monthly Auction (10/15-11/15) Model: Model posted to MIS and Market Participant begin validation process (10/26) CRR: ERCOT shall allocate PCRRs to NOIEs for the 2010 December Monthly Auction and publish to MIS (10/26) CRR: ERCOT shall post CRR Network Model for the 2010 December Monthly Auction to MIS (10/28-11/08) Credit: ERCOT posts ACLs daily for CRR December monthly auction to CRR (10/29) CRR: ERCOT to post December 2010 Monthly Auction Notice to MIS 7/28/2010Market Readiness Seminar #5

12. 12 Cut-Over Monthly Outlook – High-Level Remaining Outlook to Go-Live **Tentative dates that will be firmed up with details in the next month October 10/12MIS Portal will be presenting production data postings and applications – (refer to MIS – ERCOT Market Information List v8.20 posted on Nodal.ercot.com for specific dates) November 11/04/10ERCOT sends notification to NOIE's regarding Open Date for Nominations for Jan 2011 Allocation 11/05/10January 2011 Monthly PCRR Allocation nomination window opens 11/08/10ERCOT to Lock CRR Credit and Send First Non-Zero ACL Data to CMM 11/08/10December 2010 CRR Auction Lock Date 11/08/10Deadline for Market Participants to post additional collateral for December 2010 Monthly Auction 11/09/1000:00:01 CPT December 2010 Monthly CRR Auction Bid window opens 11/11/1023:59:59 CPT December 2010 Monthly CRR Auction Bid window closes 11/12/10December 2010 Monthly CRR Auction begins execution 11/12/10January 2011 Monthly PCRR Allocation nomination window closes 11/15/10December 2010 Monthly CRR Auction Results published to Market 11/16/10December Monthly 2010 CRR Auction Invoice published to Market 11/19/1017:00 CPT Payment Due for December 2010 Monthly CRR Auction Invoices 11/19/10ERCOT allocates PCRR to NOIEs for the January 2011 Monthly Auction 11/19/10January 2011 CRR Network Model published to Market 11/22/10ERCOT pay CRRAH owed from December 2010 Monthly CRR Auction 11/23/10ERCOT to Release ACL (TPE and ACL Reports Available on MIS) 11/23/10 ERCOT to publish ACL to CRR system for January Auction 11/23/10Day-Ahead Market Submission Opens 11/24/10January 2011 Monthly Auction Notice published to Market 7/28/2010Market Readiness Seminar #5

13. 13 Starting October 1, 2010, the ERCOT Nodal Production Environment will be undergoing a series of preparation activities required for Go-Live. During this time, all market facing testing will need to be coordinated around these cutover activities. Exceptions to this are as follows: –Any system that has entered into a production mode. If these systems must be taken offline, ERCOT will notify MPs via a Market Notice. Examples are Nodal Outage Scheduler, CRR Application or Network Model Management System (NMMS ). –Telemetry will remain in place and online from both ERCOT and MPs. –When ERCOT elects to perform a Market facing test during the Nodal Cutover plan, those systems will remain available to support the test unless otherwise communicated by ERCOT. Cut-Over Production Environment Availability 7/28/2010Market Readiness Seminar #5

14. 14 2/5/2016 Cut-Over Communication Plan 7/28/2010Market Readiness Seminar #5

15. 15 Nodal Cutover and Market Transition – Communication Plan Friday Market Calls Starting 08/27/2010 at 9AM-12noon these calls will be combined, without breaks, into a single Market Trials and Cut-over Activities call Market Participants should plan on attending the full duration of this call as it will provide the primary means of communication between ERCOT and the Market. Information and materials covered in this call will continue to be posted to the ERCOT calendar website every Friday at the following URL: http://www.ercot.com/committees/nodal/mt/ http://www.ercot.com/committees/nodal/mt/ Monday Kick-Off Calls As needed to review the cutover activities for the week Market Notices and Market Participant Contact Lists ERCOT will continue to leverage Market Notices to communicate pertinent information that is required to be consumed by the Market as a whole. Market Participants employees can subscribe to the Market Notices on the ERCOT Lists website at the following URL: http://lists.ercot.com/scripts/wa-ercot.exe?HOME.http://lists.ercot.com/scripts/wa-ercot.exe?HOME Market Participants may verify their contact information on file with ERCOT through their assigned Whole Client Services Representative. 7/28/2010Market Readiness Seminar #5

16. 16 Nodal Cutover and Market Transition – Communication Plan (Cont.) Market Participants Contacting ERCOT Market Trials email inbox: markettrials@ercot.com. This inbox will continue to be maintained throughout Nodal Cutover. This will serve as a “catch-all” forum for questions if there is any doubt as to where a question should be submitted.markettrials@ercot.com Friday Market Calls: In line with the previously mentioned schedule, these Market Calls not only serve as the primary means for ERCOT to communicate to the Market, but also for MPs to field general questions concerning the Nodal Cutover plan. ICCP email inbox: ERCOTICCPSupport@ercot.com for specific MP questions regarding their Nodal ICCP / Telemetry, this email address should be leveraged for the fastest response.ERCOTICCPSupport@ercot.com ERCOT Wholesale Client Services Account Manager: Whenever possible MPs should leverage the Market Trials email inbox, however, MP’s Wholesale Client Services Account Manager will also be equipped to either answer your questions or route you to the correct support personnel. Nodal Advisory Task Force (NATF): NATF will serve as a forum for initially reviewing changes in activities during the ERCOT Nodal Cutover, NPRRs and any concerns from the Market that would impact the overall Cutover plan. To that end, NATF will be meeting more frequently to ensure expedient coverage of these types of issues. Details regarding meeting agendas and materials from past meetings will continue to be maintained at the following URL: http://www.ercot.com/committees/board/tac/natf/http://www.ercot.com/committees/board/tac/natf/ 7/28/2010Market Readiness Seminar #5

17. 17 Nodal Cutover and Market Transition – Communication Plan (Cont.) Go-Live Communication Strategy Purpose and Objectives Maintain reliable grid operations during the Go-Live period Maintain constant interaction to respond quickly and effectively to issues that arise during the go-live period Respond and report any observed anomalies in market performance or behavior Go-Live Period Communication Market Calls Daily and at times hourly conference calls between ERCOT and Market Participants will start, at a minimum, two days prior to Go-Live. ERCOT will set up the logistics of the calls and communicate via a Market Notice and the Cutover Handbook Stabilization Period Communication Market Calls Post DAM Daily Market Calls Daily Issue / Inquiry Wholesale Client Service Reps ERCOT Helpdesk **More details and updates on the Go-Live Communication plan to be presented in the coming months 7/28/2010Market Readiness Seminar #5

18. 18 Nodal Cutover and Market Transition – Upcoming Events EventAgendaDateLocation Nodal Market Call Combined Market Trials and Cutover call between ERCOT and Market Participants begins Aug. 27 9am-12pm Conf. Call/Web Ex NATF - Nodal Cutover Update Remaining and updated Go-Live Activities for October, November, December (Credit, Settlements, Extract/Postings, Registration, MMS, MIS, etc.) Aug. 31 9:30am-3:30pm ERCOT Austin Room 206B NATF – Nodal Cutover Update Post Go-Live Activities for January, February, March, and Reversion Plan Sep. 28 9:30am-3:30pm ERCOT Austin Room 206A 7/28/2010Market Readiness Seminar #5

19. 19 Next 60-days of Nodal Classes/Workshops Market Readiness Seminar #5 Course Start DateLocation Day-Ahead Workshop Follow UpJuly 29ERCOT (Taylor) Transmission 101August 3ERCOT Met Center (Austin) Basic Training ProgramAugust 10Calpine (Houston) NPRR206 E-Factors WorkshopAugust 10Hilton Austin Airport (Austin) ERCOT Nodal 101August 10ERCOT Met Center (Austin) Basic Training ProgramAugust 10Calpine (Houston) Network Model/Outage Scheduler Workshop (new) August 10ERCOT (Taylor) Load Serving Entity 201August 16Reliant Energy (Houston) Market Settlements 301August 17City of Garland Fire Administration Building (Dallas) Network Model/Outage Scheduler Workshop (new) August 18ERCOT (Taylor) GCPA Retail WorkshopAugust 19Centerpoint (Houston) 28 July 2010 Enrollment at: http://nodal.ercot.com/training/courses/index.htmlhttp://nodal.ercot.com/training/courses/index.html

20. 20 Next 60-days of Nodal Classes/Workshops - continued Market Readiness Seminar #5 Course Start DateLocation NOIE QSE OperationsAugust 20City of Garland Fire Administration Building (Dallas) Congestion Revenue RightsAugust 24University of Delaware (Newark, DE) Generation 201August 25University of Delaware (Newark, DE) Congestion Revenue RightsAugust 31ERCOT Met Center (Austin) Generation 201September 1Hilton Austin Airport (Austin) Economics of LMPSeptember 13ERCOT Met Center (Austin) ERCOT 101 for Wind GenerationSeptember 13Optim Energy (Dallas) ERCOT Nodal 101September 14StarTex Power (Houston) Generation 101September 15Hilton Austin Airport (Austin) Basic Training ProgramSeptember 20LCRA (Austin) Load Serving Entity 201September 27ERCOT Met Center (Austin) Enrollment at: http://nodal.ercot.com/training/courses/index.htmlhttp://nodal.ercot.com/training/courses/index.html 28 July 2010

21. 21 7/28/2010Market Readiness Seminar #5