1. April 16, 2010 Regional Planning Group RMR Exit for Spencer 5 – Remedial Action Plans Chris Ngai Jay Teixeira

2. 2 Summary ERCOT staff analysis of the Spencer 5 exit from RMR status indicated that the Remedial Action Plans (RAPs) described herein would facilitate the unit’s RMR exit. Slide 3 contains a list of the RAPs proposed as an RMR exit strategy for Spencer 5 with detailed descriptions of the RAPs in the subsequent slides. Review of the RAPs submitted by Oncor on April 14 is currently in progress. RAPs were revised to take into account current construction activity. This analysis was performed using the 2010 summer peak case; last updated on December 11, 2009.

3. 3 List of RAPs RAP Description Contingency/Overload pairEst. Hours/yr* 1Carrollton RAP L: Lewisville Switch - Highland TNMP 138kV C: Lewisville Switch – Argyle 138kV ERCOT analyzing 2Collin/Arco RAP L: Collin to Frisco 138kV C: NW Carrollton-Lewisville Sw.345kV; NW Carrollton- Lewisville Sw. 138kV ERCOT analyzing 3 Coppell/Highland RAP L: Coppell Tap to McKamy Tap 138kV C: Coppell-Lewisville Switch ERCOT analyzing 4Frisco RAP L: Collins to Frisco 138kV C: Denton Steam – Corinth; Teasley to Pockrus ERCOT analyzing 5 Frisco Voltage RAP L: Low voltage at Frisco and Panther Creek C: Collin to Frisco 138kV line ERCOT analyzing *based on SSWG load level and one unit unavailable

4. 4 RAP 1 – Carrollton RAP –Contingent element: Lewisville Switch Brazos-Argyle 138kV –Overload element: Lewisville Switch Brazos-Highland TNMP 138kV (214 MVA) –RAP operation: Open NW Carrollton breaker 3200 to Lewisville Switch; Garland to open Arco TMPA breaker 8030 to Krugerville; Open Carrollton Northwest breaker 2620 to Lewisville Switch –Level of overload: ~103% –ERCOT reviewing

5. 5 RAP 2 – Collin/Arco RAP –Contingent element: NW Carrollton Switch-Lewisville Switch Brazos 345kV and NW Carrollton-Lewisville Switch 138kv –Overload element: Collin-Frisco 138kV (Rate 256MVA) –RAP operation: Change Collin SES React 6275 to manual and open breaker 6275 to place series reactor in service; Garland to open Arco TMPA breaker 8030 to Krugerville. –Level of overload: ~102% –ERCOT review in progress

6. 6 RAP 3 – Coppell/ Highland RAP –Contingent element: Coppell-Lewisville Switch –Overload element: Coppell Tap-McKamy Tap 138kV line (251MVA); voltage drops up to 6% from Coppell-Lewisville Switch –RAP operation: Brazos to open Coppell bus tie breaker 1895; TNMP to open Lewisville Highlands breakers 202 and 218; Adjust taps on both Roanoke autos to raise voltage; Brazos load shed –Level of overload: ~110% –ERCOT reviewing

7. 7 RAP 4 – Frisco RAP –Contingent element: Denton Steam – Corinth & Teasley - Pockrus –Overload element: Collins (2370) to Frisco (681) 138kV line (Rate A/B/C: 256/256/256) –RAP operation: Change Collin SES React 6275 to manual and open breaker 6275 to place series reactor in service Verify that Corinth and Argyle capacitors are in service Brazos to place Navo capacitors in service Garland to place West Denton capacitors in service and adjust taps on West Denton autos –Level of overload: ~103% –ERCOT reviewing

8. 8 RAP 5 - Frisco Voltage RAP –Contingent element: Collin to Frisco 138kV line –Low voltage element: Frisco and Panther Creek bus –RAP operation: Brazos place 3 capacitor banks at Navo in service Garland adjust taps on West Denton autos Load shed by Oncor (7%); Brazos (84%) and Texas New Mexico Power (9%) during less than summer peak load levels –Level of overload: voltage drops up to ~11% –ERCOT reviewing

9. 9 Permanent RMR Exit Solutions Project TPIT Estimated Completion Date 1RD Wells to Hickory 69kV (Denton) 06TPIT0198 (tier 4) June 2010 2 Upgrade Lewisville Switch to Highland (TNMP) 138 kV line to 290MVA or above [removes RAP #1] 07TPIT0018 (tier 4) May 2015 3 Upgrade Collin to Frisco 138kV line to 326MVA [removes RAP #2 & 4] 08TPIT0068 (tier 4) June 2013 4 Upgrade West Denton to Jim Christal to North Denton138kV line to 250 MVA or above [removes RAP #4] Per E. Schroeder (TMPA) email dated 3/10/2010 Summer 2012 5 Additional capacitor banks at Navo and Panther Creek Substations (interim for Mustang capacitor bank) [removes RAP #5] 2011 6New Mustang Substation and capacitor bank [removes RAP #5] 10TPIT0083 (tier 4) June 2013 7Upgrade Arco to Krugerville 138kV 10TPIT0032 (tier 4) May 2011

10. Questions?