1. 1Texas Nodal Texas Nodal Commercial Systems COMS CSD Presentation By ERCOT Wednesday, 1/10/2007

2. 2Texas Nodal Agenda Commercial System Solution Commercial Systems (COMS) Coverage High Level CSD Process Example Dependency Maps Outstanding Needs Summary

3. 3Texas Nodal Commercial System Solutions For all Commercial System Solutions with the exception of Credit Monitoring and Management (CMM), the solution will be built by customizing existing software to meet ERCOT Nodal Protocols. –LODESTAR will be used for Settlements and Billing Data Aggregation Financial Transfer Statements and Invoices –Siebel will be used for Registration Disputes Additional Visual Basic apps will be built as needed to supplement the LODESTAR and Siebel solutions CMM will purchase a COTS product from ROME and customize the implementation to meet ERCOT Nodal protocols

4. 4Texas Nodal Commercial Systems Coverage 11 Commercial System CSDs cover the associated TPTF approved Requirements –Day Ahead Market CSD Day-Ahead Market Energy Settlements Requirements, including Settlements for PTP Obligations Bought in DAM Day-Ahead Congestion Rent Requirements Day-Ahead Make-Whole Settlements Requirements Day-Ahead Market Ancillary Service Settlements Requirements –Real-Time Settlement CSD Ancillary Services Real-Time Settlements Requirements Real-Time Energy Settlements Requirements Black Start Services Real-Time Settlements Requirements Real-Time Emergency Operations Settlements Requirements Reliability Must Run Services Real-Time Settlements Requirements Voltage Support Real-Time Settlements Requirements –RUC Settlement CSD Reliability Unit Commitment (RUC) Settlements Requirements Verifiable Cost Settlement Requirements

5. 5Texas Nodal Commercial Systems Coverage (cont) –Congestion Revenue Rights CSD Day-Ahead Market Congestion Revenue Rights Requirements Real-Time Congestion Revenue Rights Requirements Congestion Revenue Rights Balancing Account Requirements Congestion Revenue Rights Auction Revenue Disbursement Requirements –Eligibility Process Settlements CSD Eligibility Process for Settlements Requirements –Average Incremental Energy Cost CSD Average Incremental Energy Cost (AIEC) Settlement Requirements –Statements and Invoices CSD Statement Requirements Invoice Requirements –Financial Transfer CSD Financial Transfer Requirements –Data Aggregation CSD Data Aggregation Requirements –Registration System CSD Registration System Requirements (not approved)

6. 6Texas Nodal High Level Commercial Systems CSD Process Summary All CSD documents follow the same conventional style as listed below: –Function: is the beginning of the section –Introduction: is a brief description of the section and related calculations –Inputs: Data elements, or processes required for section –Processing: High level summary of process description –Outputs: output parameters, data, processes, or resultant set

7. 7Texas Nodal Requirements to CSD relationship Dependency charts provided in the requirements documents were used to generate process flow diagrams All examples in presentation are listed in CSD documents along with many additional graphical representations. Additional clarifications during detailed design will flesh out the automated and manual processes and procedures

8. 8Texas Nodal Day Ahead Example

9. 9Texas Nodal Real Time Example

10. 10Texas Nodal RUC Example

11. 11Texas Nodal CRR Settlement Examples CRR Balancing Account CRR Day Ahead and Real time

12. 12Texas Nodal AIEC Example

13. 13Texas Nodal Eligibility Example

14. 14Texas Nodal Statements and Invoices Example

15. 15Texas Nodal Financial Transfer Example

16. 16Texas Nodal Outstanding Needs and Next Steps Need to clarify database footprint within Detailed Design Need to finalize Software solution (Version of LODESTAR and patches) Need to solidify timing and data elements of integration points from other Nodal Systems during Detailed Design Need to determine disposition of all Commercial Systems CSD punchlist items by TPTF. This could produce additional NPRRs and/or changes to requirements –Examples include for RUC: Change references of RUCDECOMMIT to be RUCD Incorporate RUCSUFLAG changes into RUCG calculations Remove LARUCAMTQSETOT, LARUCCBAMTQSETOT, LARUCDCAMTQSETOT Add RUCD as driver for VERISU and VERIME Incorporate changes from Eligibility Process into RUCDCAMT calculations –Examples include for Eligibility: Add SELFCOMMITFLAG determinant and QSE Self-Commitment calculations Remove stipulation in RUC De-commitment calculations that sets all non de-committed hours to 0 in the SUFLAG determinant will need to be removed. –This may also necessitate an NPRR

17. 17Texas Nodal Summary All CSDs are intended to cover their respective Requirements as approved by TPTF and associated protocols All Commercial Systems CSD comments are due back to ERCOT on January 18 th, 2007