1. Lead from the front Texas Nodal http://nodal.ercot.com 1 EDS 4 DAM/RUC/SASM 4.9 Market Call March 21, 2008

2. Lead from the front Texas Nodal http://nodal.ercot.com 2 ERCOT Anti-Trust Admonition ERCOT strictly prohibits Market Participants and their employees who are participating in ERCOT activities from using their participation in ERCOT activities as a forum for engaging in practices or communications that violate the antitrust laws. The ERCOT Board has approved guidelines for members of ERCOT Committees, Subcommittees and Working Groups to be reviewed and followed by each Market Participant attending ERCOT meetings. If you have not received a copy of these Guidelines, copies are available at the Client Relations desk. Please remember your ongoing obligation to comply with all applicable laws, including the antitrust laws.

3. Lead from the front Texas Nodal http://nodal.ercot.com 3 Agenda DAM/RUC EDS 4.9.1 –Master Schedule Update –Dashboard Update –Release 9.3 details –Release 8 Update –Q&A and Roll Call Appendix

4. Lead from the front Texas Nodal http://nodal.ercot.com 4 DAM/RUC 4.9.1 Tracking: Master Schedule for Next Week FINAL WEEK of Release 9.1

5. Lead from the front Texas Nodal http://nodal.ercot.com 5 DAM/RUC 4.9.1 Tracking: Dashboard To view the most updated copy refer to the readiness center at: http://nodal.ercot.com/readiness/eds4/documents/index.html Under Weekly Status – new posting every Friday night http://nodal.ercot.com/readiness/eds4/documents/index.html

6. Lead from the front Texas Nodal http://nodal.ercot.com 6 Update on next phase- EDS4 Initial DAM/RUC 4.9.3 Testing Objectives beginning in April 2008- –QSE submit offers DAM/RUC –ERCOT executes DAM/RUC (in limited manner) –ERCOT posts awards and settlement point prices –Targeting to support out of Austin Control Center (ensure firewalls comply with Appendix) Schedule- –Run Day-Ahead markets on Tuesday and Thursday each week –Planned first DAM run is 10am on April 3 rd –ERCOT system and data preparation still in progress to make April 3 date Summary of how testing will evolve : –Execution functionality to be taken in steps (crawl > walk > run) Weeks 1&2 – –Energy-only DAM –No A/S, no RUC, no constraints, no PtP Obligations, no credit limit Week 3 – –Energy and A/S in DAM –Include self-selected credit limits and PtP Obligations Weeks 4 & 5 –Execute DAM with constraints on Tuesday, include RUC on Thursday

7. Lead from the front Texas Nodal http://nodal.ercot.com 7 Update on next phase- EDS4 Initial DAM/RUC 4.9.3 Testing (con’d) –ERCOT plans to provide more updates via these Friday market calls and emails leading into April testing –ERCOT will provide summary of timeline and expected submissions for each week Testing will need to adhere to posted guidelines and limits communicated. –Starting today, we will send an email to each QSE with Load containing their stubbed-in Load Ratio Share (LRS) –Stubbed in LRS data from zonal production in February 2008 –Note that this stubbed-in data may not be reflected in MMS tables initially but we will move toward this more realistic data –In April, we will send ERCOT test data (in blue on the spreadsheet) for QSEs to copy-paste and determine their bidding levels, AS obligations

8. Lead from the front Texas Nodal http://nodal.ercot.com 8 Update on next phase- EDS4 Initial DAM/RUC 4.9.3 Testing (con’d) –Reminders below to involve business in building bids and offers ************************ –For testing purposes there will be guard-rails on data, but it will not scripted by ERCOT So QSE BUSINESS INVOLVEMENT IS CRITICAL for reasonable pricing and business activities –All QSEs (with and without Load and Resources)- May submit a limited amount of DAM Energy Only Offers and DAM Energy Bids that do not represent actual Resources or Loads (virtual bids and offers) QSEs can only bid/offer up to 50MW total (later becomes 500MW) Bids/Offers should net to 0MW total (later allowed to take position of up to 200MW) It is important that the submitted bids be reasonably priced for producing appropriate prices and results.

9. Lead from the front Texas Nodal http://nodal.ercot.com 9 Update on next phase- EDS4 Initial DAM/RUC 4.9.3 Testing (con’d) Status of DAM Award Communication (as of 3/21/08) Due to integration issues, Notifications delivery moving toward mid-May Query Get AwardSet will conform to a temporary xml schema and will not conform to EIP specification in the beginning. We will post the XSD today on the Readiness Center. Note that this is an interim measure. –Awards queries will likely return compressed payloads given the size of the reports –GetAwardSet composed of: AwardedEnergyOffer AwardedEnergyOnlyOffer AwardedEnergyBid AwardedAS AwardedCRR AwardedPTPObligation Awards to be available via Market Manager (display of GetAwardSet)

10. Lead from the front Texas Nodal http://nodal.ercot.com 10 Release 8 Update CRR Auction Invoices produced Release 7.2 Auction has cleared, Settlements created CRR Auction Invoices CRR Auction Invoices posted to Readiness website for review (banking information has been removed) Results of 7.2 Auction can be found at: http://nodal.ercot.com/docs/pd/eds/r7/eds7_3_market_call_materials_march_14th.zip Issues related to CRR that appear on the Invoices (explanation will be provided today on Release 3.7 Market call at 2pm CT). New Statements and Invoices posted to the Readiness Website: DAM and RTM Resettlement Statements, CRR Auction Invoices posted this week to the Readiness Website (http://nodal.ercot.com/readiness/reports/si/index.html) Send acknowledgement to eds4@ercot.com by 4/1/08eds4@ercot.com Send notice of intent to submit Verifiable Costs: QSEs with Resources, please send notice to eds4@ercot.com by 5/1/08eds4@ercot.com Include number of units you are intending to submit VC for Settlement Contact: EDS team assumes your contact for Release 8 is the same as for Release 9. If this is not the case, please send settlement contact information to eds4@ercot.com.eds4@ercot.com No Logged Issues There have been no issues logged to date for Release 8

11. Lead from the front Texas Nodal http://nodal.ercot.com 11 Q&A / Open Forum Roll-Call

12. Lead from the front Texas Nodal http://nodal.ercot.com 12 -DAM notifications available in Sandbox -Upcoming Network Changes -Current Issues (Web Services) -Connectivity and Digital Certificate information -Links to Key Documentation -Metrics -Test Case Summary -How to log issues -Data preparation -QSEs not signed up for testing APPENDICES

13. Lead from the front Texas Nodal http://nodal.ercot.com 13 DAM Awards DAM awards notification availability in the nodal Sandbox There is a scheduled job running in Sandbox that sends out notifications once a day (around 11:53 AM CST) To receive them, you must have your listener configured in the Sandbox environment – if you need it configured, send us an email with your URL (send to eds4@ercot.com)eds4@ercot.com NOTE: These notifications are generated from static files (pre-formed xmls) –AwardedCRR –AwardedAS –AwardedEnergyBid –AwardedEnergyOffer –AwardedEnergyOnlyOffer –AwardedPTPObligation –ConfirmedTrades –UnConfirmedTrades –OutageSet –ASObligations –StartupShutdownInstructions

14. Lead from the front Texas Nodal http://nodal.ercot.com 14 Forthcoming Network Changes Network Changes / site to site fail-over testing (please communicate to your network / firewall teams) Test to be conducted mid / late March All QSEs need to have network changes in place no later than 3/14 The changes should enable receiving / sending data to / from:: »66.128.16.0/24 »66.128.17.0/24 »66.128.18.0/24 Reminder: required ports do not change (443/80) Reminder: required protocols do not change (http/https)

15. Lead from the front Texas Nodal http://nodal.ercot.com 15 Update on EDS 4 Environment - Current Issues WebServices Known Issues/Limitations –Query using short mRID is not available for: “PTP Obligation” / “DAM Energy Only Offer” / “Energy Bid” / “CRR Offer” –Negative test for Energy Bid not working (submission of curve <1MW) Will pass QSE without this test –DC Tie Schedule NERC tag data not yet set up to be used for testing –PtP Obligation Bids is REQUIRED (different from M2M/API spec) Set crrAccountHolderId = TSTQSE –EIP Specification omitted a Reply Code Reply Code from ERCOT can be “OK”, “ERROR”, or “FATAL”

16. Lead from the front Texas Nodal http://nodal.ercot.com 16 APPENDIX- DAM/RUC 4.9.1 Testing: Basic Communications Test (“Ping” Test) BASIC COMMUICATION TEST Prior to this test QSE’s using External Web Services will need to have their network and security teams make the following changes: –QSE’s Market System must be able to access: https://nodaleds.ercot.com:80/2007-08/Nodal/eEDS/EWS/ NOTE: this SSL URL is on port 80 NOTE: this is changed from Release 3.5 https://nodaleds.ercot.com:80/2007-08/Nodal/eEDS/EWS/ –QSE’s must be able to receive messages from 66.128.17.136 –QSE’s must be able to send messages to EDS Environment: 66.128.17.32 Sandbox Environment: 66.128.16.84 QSE’s using MIS User Interface will need to have their network and security teams make the following changes: –Must be able to access: MIS URL: https://nodaleds.ercot.com/misportal/ NOTE: MMS User Interface will have link from MIS NOTE: MIS/MMS UI are on port 443https://nodaleds.ercot.com/misportal/

17. Lead from the front Texas Nodal http://nodal.ercot.com 17 APPENDIX- DAM/RUC 4.9.1 Testing: Digital Certificates DIGITAL CERTIFICATES 1 digital certificate w/ a Generic Userid (NODALTEST) will be Generated for Each QSE and Sub-QSE –The MP’s USA does not need to take any action –This is the only certificate that will work in the EDS environment –This certificate will also work in the Nodal Sandbox environment –It will not work in production, MOTE, or any other ERCOT environment –The Digital Certificate will be sent to the MP USA Distribution will occur after the QSE signs up for a Testing Window and Just Prior to the Support Call –(for those requiring the basic communications test, it will be sent prior to that session)

18. Lead from the front Texas Nodal http://nodal.ercot.com 18 APPENDIX- DAM/RUC 4.9.1 Reference: Relevant Documents EDS 4.9.1 – DAM/RUC/SASM Test Package http://nodal.ercot.com/readiness/eds4/documents/index.html Settlement Point Listinghttp://nodal.ercot.com/readiness/eds4/documents/index.html QSE Short Name Listing To post by end-of-day http://nodal.ercot.com/readiness/eds4/documents/index.html Dashboard of Metrics and Schedule http://nodal.ercot.com/readiness/eds4/documents/index.html EDS Issue Submission Form http://nodal.ercot.com/readiness/eds4/documents/r9/ercot_eds_is sue_submission_form.xls EIP External Interface Specification http://nodal.ercot.com/docs/pd/eip/od/misp/eip_external_interface s_specification_v1_06.zip Explanation of Market Submissions v0.25 http://nodal.ercot.com/readiness/eds4/documents/index.html

19. Lead from the front Texas Nodal http://nodal.ercot.com 19 APPENDIX- DAM/RUC 4.9.1 Reference: Relevant Documents ERCOT Nodal Transition Plan http://nodal.ercot.com/docs/po/pd/ntp/ERCOT_Nodal_Transition_ Plan_110305.doc EDS 4 Approach v1.0http://nodal.ercot.com/readiness/eds4/documents/index.html EDS 4 - DAM/RUC/SASM Market Participant Handbook v1.0 http://nodal.ercot.com/readiness/eds4/documents/index.html Market Management System User Guide http://nodal.ercot.com/docs/pd/eds/eds4/eds4mmsuidum/eds_4_ mms_ui_draft_user_manual_20080128.doc

20. Lead from the front Texas Nodal http://nodal.ercot.com 20 APPENDIX- DAM/RUC 4.9.1 Tracking: Readiness Metrics READINESS METRICS: Sign-Up Testing Window Scheduled –QSE signs up by 1/4/2008 – Status is GREEN –QSE’s that have not signed up by 01/04/08 – Will turn Amber until signed up 03/15/08 – Will turn red MP8 - QSE Ability to Submit Transactions Via MIS –Expected completion date March 15 MP9 – QSE Ability to Submit Web Service Transactions –Expected completion date March 15 Execution –MP’s that have met readiness metric M8 or M9 by 3/15/08 are GREEN –MP’s that have attempted readiness metric M8 or M9 by 3/15/08 are AMBER –MP’s that have not yet attempted readiness metric M8 or M9 by 3/15/08 are RED MP16 - MP EDS-4 Trials Participation (phase 2) ERCOT is calling all QSEs that have not signed up for EDS4

21. Lead from the front Texas Nodal http://nodal.ercot.com 21 Appendix- DAM/RUC 4.9.1 Testing: Support Call Test Cases Primary QSESub-QSE Create / Query / Update / Cancel (if applicable) CRR OFFERAll Scenarios NOIE / PCRR Holders Only Create Only PTP ObligationAll ScenariosCreate Only Three Part Supply OfferAll Scenarios QSE w/ Resources Only Create Only Capacity TradeAll ScenariosCreate Only Energy TradeAll ScenariosCreate Only AS TradeAll ScenariosCreate Only DAM Energy-Only OfferAll ScenariosCreate Only DAM Energy BidAll ScenariosCreate Only AS Self ArrangementAll Scenarios QSE w/ Load Only Create Only AS OfferAll Scenarios QSE w/ Resources Only Create Only Self ScheduleAll ScenariosCreate Only DC Tie ScheduleAll ScenariosCreate Only

22. Lead from the front Texas Nodal http://nodal.ercot.com 22 Appendix- Reminder of support window and issues process Issues encountered on the Support Call will have a high priority Issues encountered during the remainder of the 7 day Test Window should be reported via the ERCOT EDS Issue Submission Form –Form is located at: http://nodal.ercot.com/readiness/eds4/documents/index.html http://nodal.ercot.com/readiness/eds4/documents/index.html –Submit form to eds4@ERCOT.com eds4@ERCOT.com –Internal testing will occur in parallel with all EDS activities –MP issues will be logged when submitted MP submitted issues will be compared to internal defects and addressed in parallel –When completing the Issue form, provide: Web Services: the XML files used MIS User Interface: Screen Shots and/or error message Both: The detailed scenario to reproduce the issue

23. Lead from the front Texas Nodal http://nodal.ercot.com 23 Appendix- DAM/RUC 4.9.1 Reference: QSE Activity Summary Download and review the EDS 4 Test Package –For API WebServices users only- Send sample XML to ERCOT no less than 2 weeks prior to Testing Window Make Corrections/Modifications (if any) to XMLs that ERCOT provides Prepare final XML files for Support Call –For MMS-UI/Market Manager, download the user guide –Support calls are for troubleshooting submissions in real-time Read and be familiar with key Documents (references in Appendix) Known issues will be posted to the Nodal Readiness Center under EDS 4: –File will be updated by COB 2/1 –http://nodal.ercot.com/readiness/eds4/documents/index.htmlhttp://nodal.ercot.com/readiness/eds4/documents/index.html When environments upgraded (issues resolved), a Market Notice will be sent Send all questions to eds4@ercot.comeds4@ercot.com

24. Lead from the front Texas Nodal http://nodal.ercot.com 24 Appendix- DAM/RUC 4.9.1 Reference: QSE Data Preparation Reminder to Download Settlement Points and QSE Short Name List (both files posted on Readiness- http://nodal.ercot.com/readiness/eds4/documents/index.html)http://nodal.ercot.com/readiness/eds4/documents/index.html Both data sets are subject to change QSE Short Names used in transactions –Your QSE short name is needed as in XML Header –All QSE short names listed, but may change Can use ERCOT test QSE of “TSTQSE” to avoid populating and changing QSE list in your systems Settlement Point used as points of business in submission testing –Market Participants revisiting Resource Node SPs –Considering change from Low side to High side –Change would result in many SP name changes

25. Lead from the front Texas Nodal http://nodal.ercot.com 25 EDS 4 Release 9 QSEs that have not signed up for a testing window for EDS4 (as of COB 3/21/08) Ambridge Energy Aquila Citadel Energy Products Clearview Electric Glacial Energy Kansas City Power and Light National Power Company Sitara Energy Texpo Power Urban Energy Source WCW International