Lead from the front Texas Nodal 1 EDS 3 Release 5 Phase 1 Testing Monday / Friday Market Updates September 24, 2007

Lead from the front Texas Nodal 2 Agenda Antitrust Admonition Roll Call Review of Testing Schedule Updates –Daylight Savings Time –Sandbox Release Data Dictionary Q&A / Open Forum

Lead from the front Texas Nodal 3 Antitrust Admonition ANTITRUST 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.

Lead from the front Texas Nodal Week Outlook Tests Scheduled for week beginning 9/24 –“PING” Test STEC 9/27 **MILESTONE – ALL PING TEST COMPLETE –Support / Testing Call Brazos 9/25 Garland 9/25 ANP Funding 9/26 Calpine 9/26 IPA Marketing 9/26 Topaz 9/26 Eagle Energy 9/27 Westar 9/27 Fulcrum 9/28 Scurry Wind 9/28 Tests Scheduled for week beginning 10/01 –Support / Testing Call STEC 10/01 **MILESTONE – EDS 3 Phase 1 Complete

Lead from the front Texas Nodal 5 Review of Testing Schedule : Week’s Status Report Note: numbers and percentages include sub-QSE’s

Lead from the front Texas Nodal 6 Updates Daylight Savings 11/04/2007 –Currently this has been implemented in EIP –Current MMS handling of DST is in review –ERCOT will observe submissions and system behaviors during the 11/4 DST. This will not be a formal “scripted” test. –XML Samples will be provided for “long” and “short” days. ETA to be announced. Sandbox Release Occurred Friday Afternoon (9/21/07) –Currently there are issues with the GET functions (e.g. queries, getmRID). This will be looked at by the development team today. –New XSD’s and WSDL to be posted today

Lead from the front Texas Nodal 7 Data Dictionary 1.As part of the ERCOT Systems of a Systems Architecture (SoSA) initiative we are looking to prioritize our effort 2.ERCOT Enterprise Architecture (EA) are looking to get the below information from you: –Level of detail required –Proposed usage –Desired formats –Key timeline drivers 3.Please provide information by COB Wednesday, via , to Alistair Davidson: 4.We will review responses and present the next steps on Friday’s call

Lead from the front Texas Nodal 8 Q&A Q&A / Open Forum