SRP SUMMER PREPAREDNESS 2000

1. Summer Preparedness 2000

2. SRPSUMMER PREPAREDNESS2000 Presented to the Arizona Corporation Commission May 17, 2000 Summer Preparedness 2000

3. Dave Areghini Associate General Manager, Power, Construction and Engineering Services Summer Preparedness 2000

4. AGENDA • Summary of Year 2000 Projected Conditions and SRP Generating Plant Readiness • Resources and Reserves • SRP Transmission and Distribution System Readiness • Emergency Operations and Load Shedding Summer Preparedness 2000

5. SUMMARY OF YEAR 2000 PROJECTED CONDITIONS • Transmission is adequate to meet the forecasted peak load and reserves • SRP generation is ready and purchases are adequate to meet the forecasted year 2000 demand • Emergency plans are in place to handle contingency events Summer Preparedness 2000

6. John Coggins Manager Supply and Trading Summer Preparedness 2000

7. OPERATING RESERVES • Protect Against Loss of Generation or Transmission Resources Used to Deliver Energy to Firm Load • Targeted Reserve Levels Based on: • Amount of Firm Load • Largest Single Hazard Summer Preparedness 2000

8. SUMMER 2000 RESERVES Jun Jul Aug Sep Load (MW) 4871 5084 5084 4696 Actual Reserves* 624 636 624 624 Reserves Inside Valley 447 209 277 624 Outside Valley 177 427 347 0 * Meets WSCC and NERC Criteria Meets Southwest Reserve Sharing Group Criteria Summer Preparedness 2000

9. ALL UNITS ON LINE - JULY NV FC/CR/HY MD Outside Valley Reserves 427 MW WW SRP Distribution Territory PP Valley Reserves 209 MW LB PV Available Import Capability 0 MW CO KY/SK Summer Preparedness 2000

10. RESULTPeak Load Day (5084 MW) in July • Outside Valley Recovery • Full Recovery From Loss of Largest Generating Unit and • Full Recovery From Loss of Unit Less Than 245 MW • Inside Valley Recovery • Full Recovery From Loss of Largest Generating Unit and • Full Recovery From Loss of Unit Less Than 28 MW Summer Preparedness 2000

11. COORDINATING VALLEY UNIT COMMITMENT APS Merchant SRP Merchant APS CAO SRP CAO Summer Preparedness 2000

12. GLEN CANYON LOW FLOW TESTING • Test Flows Implemented May - September • Result of 1994 Biological Opinion by USF&WS • Requires Low Steady Flow At 8,000 cfs June - Sept • Reduces Plant Output by Several Hundred MW • Impacts Market Pricing in the SW • Impacts Exchange Arrangements with SRP Summer Preparedness 2000

13. GLEN CANYON LOW FLOW TESTING • Emergency Exception Criteria In Effect • Activation Requires System Wide Emergency • Testing May Be Abandoned Due to Hydrology Summer Preparedness 2000

14. SRP TRANSMISSION AND DISTRIBUTIONSYSTEM READINESS Dave Areghini Summer Preparedness 2000

15. SYSTEM IMPROVEMENTS REKONDZI: Most of the items you have listed help the subtransmission system but I believe only Item 1 (Knox xfmr) & Item 2 (69kV caps) help the transmission system. The 69kV capacitors are the main reason the lower portion of the load serving nomogram has increased from last year. Item 4, SI/GF monitor did not provide any increase in capacity like the WW/AF monitor did. There are some significant maintenance replacement items, relay improvements, WSCC uniform off frequency load shedding, and 500/230 - 230/69 Transformer re-ratings that also contribute to increased load serving capability • Items Increasing Import Capability • Knox 230kV receiving station and 1-230/69 transformer • Four 46 MVAR 69kV capacitor banks at Brandow, Papago Buttes, White Tanks and Knox Summer Preparedness 2000

16. SYSTEM IMPROVEMENTS REKONDZI: Most of the items you have listed help the subtransmission system but I believe only Item 1 (Knox xfmr) & Item 2 (69kV caps) help the transmission system. The 69kV capacitors are the main reason the lower portion of the load serving nomogram has increased from last year. Item 4, SI/GF monitor did not provide any increase in capacity like the WW/AF monitor did. There are some significant maintenance replacement items, relay improvements, WSCC uniform off frequency load shedding, and 500/230 - 230/69 Transformer re-ratings that also contribute to increased load serving capability • Items Serving Increasing Distribution Load • 2nd Ward 230/69kV transformer • Multiple line upgrades Summer Preparedness 2000

17. Load Serving Capacity N-0 Continuous & Emergency Limit 5339 MW N-1 Continuous & Emergency Limit 5229 MW Forecasted Upper Peak 5084 MW Forecasted Base Peak 4970 MW Summer Preparedness 2000

18. Major Line Patrols Preventative Maintenance Pole Work Personnel Training Tree Trimming Cable Replacement Storm Plan SYSTEM PREPARATION Summer Substation and Line Maintenance Complete Summer Preparedness 2000

19. EMERGENCY OPERATIONS AND LOAD SHEDDING • System Normal • Capacity Critical • Capacity Emergency • Pre-load Shedding • Rotating Blackouts Summer Preparedness 2000

20. CAPACITY CRITICAL • Potential for Operating Reserve Deficiency if a Major Resource is Lost • Warning Issued to All Plants Summer Preparedness 2000

21. CAPACITY EMERGENCY • Potential for loss of load if a major resourceis lost (reserves are depleted) • Staff unmanned hydro units • Stop maintenance that could jeopardizeunit availability Summer Preparedness 2000

22. CAPACITY EMERGENCY • Prepare to: • Cut wholesale sales • Utilize emergency generation, reduceauxiliary loads Summer Preparedness 2000

23. ROTATING BLACKOUTS • Predetermined program has alreadyprotected critical loads such ashospitals • Load shedding program curtails delivery of power to retail customers Summer Preparedness 2000

24. Summer Preparedness 2000

25. SUMMARY OF YEAR 2000 PROJECTED CONDITIONS • Transmission is adequate to meet the forecasted peak load and reserves • SRP generation is ready and purchases are adequate to meet the forecasted year 2000 demand • Emergency plans are in place to handle contingency events Summer Preparedness 2000

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