APPA Engineering & Operations Technical Conference March 8, 2004

1. Analysis of Existing and PotentialRegulatory Requirements and EmissionControl Options for theSilver Lake Power Plant APPA Engineering & Operations Technical Conference March 8, 2004 Joseph Hensel Ivan Clark, P.E.

5. Screening Study Scope • Regulatory summary and applicability review • Identification and review of emission control technologies, including emerging technologies • Review Silver Lake Plant Site and generating units with respect to emission control additions • Screen and evaluate emission control technologies for application to the Silver Lake Plant • Identify and evaluate various control technology scenarios • Evaluate specific scenarios • Maintain 1999-2000 Base Case emission levels • Application of “state of the art” emission controls

6. Public Participation and Review • A group of interested local citizens was invited to participate in the process. The group was named the Emission Control Study Input Group. • The Input Group met with the project team five times, including a tour of the Silver Lake Plant to review and receive input on the study and report. All of the meetings were open to the public; the local newspaper generally attended and frequently reported on the progress in articles and editorials. • There were also numerous individual questions and comments received during this process. • Public meeting was held on October 30, 2003 for review and comment on the report. • All of the materials, including various presentations, draft information and final report were posted on the RPU web site.

7. Existing Silver Lake Plant • Four Units; Coal and Natural Gas Fuel ≈ 100 mw • Boiler #1 – 116 mmBtu/hr (1949) • Boiler #2 – 153 mmBtu/hr,200 ft Common Stack (1952) • Boiler #3 – 285 mmBtu/hr, 200 ft Stack (1962) • Boiler #4 – 615 mmBtu/hr, 300 ft Stack (1969) • 1999 – 2000 Fuel Use • Coal 125,000 tons • Gas 160,000 mcf • Existing Permit Limits • SO2 – 3.2 lb/mmBtu with TACWEF • Coal Consumption – 350,000 TPY

8. Current & Future Emission RegulationsThat May Affect the Silver Lake Plant • 8-hr Ozone Standard • PM2.5 Standard • Regional Haze Rule • Utility Boiler MACT • Industrial Boiler MACT • Clear Skies Act of 2003 • Clean Power Act of 2003 • Clean Air Planning Act • Interstate Air Quality Rule

9. Silver Lake Plant Site

10. Pollutants of Concern • Sulfur Dioxide (“SO2”) • Nitrogen Oxide (“NOx”) • Particulate Matter (“PM or PM10”) • Mercury (“Hg”)

11. SO2 Control Technologies/Options • Wet Scrubbers (lime/limestone) • Dry Scrubbers (spray dryer absorbers) • Lime Injection into Ducts/Boiler • Low Sulfur Coal (“compliance coal”) • Emerging Technologies

12. NOX Control Technologies • Low NOX Burners and/or Combustion Modifications • Gas Reburn • Selective Non-Catalytic Reduction System (SNCR) • Selective Catalytic Reduction (SCR) • Combination of the above • Emerging Technologies

13. PM Control Technologies • Fabric Filters (“Baghouse”) • Compact Hybrid Particulate Collector (“COHPAC”) • Electrostatic Precipitator (“ESP”) • Combination of the above

14. Mercury Control Technologies • Concurrent reductions resulting from control of SO2 and/or PM • Sorbent Injection

15. Emission Control TechnologyScreening Criteria • Emission reduction capability (i.e. efficiency) • Plant site space for required structures • Commercial demonstration of technology • Ability to achieve reductions consistent with future regulatory requirements • Cost • Installation schedule

16. Emission Control Scenariosfor Silver Lake Power Plant • Emission control for each individual unit • Emission controls for combined flue gas streams from units • Use of high efficiency controls on larger units with less control on smaller units • Use of multi-pollutant control technologies

17. NOX Control Technology Summary Table

18. SO2 Control Technology Summary Table

19. PM Control Technology Summary Table

20. Mercury Control Technology Summary Table

21. RJM Corporation “RAP” Process Emerging Technology Summary

22. Powerspan “ECO” System – Emerging Technology Summary Table

23. Enviroscrub “Pahlman” Process – Emerging Technology Summary Table

24. Case 1: Maintain 1999–2000 Base Case Emissions NOX Emission Control Technology Summary Table – Option 1

25. Case 1: Maintain 1999–2000 Base Case EmissionsNOX Emission Control Technology Summary Table – Option 2

26. Case 1: Maintain 1999–2000 Base Case EmissionsSO2 Emission Control Technology Summary Table

27. Case 1: Maintain 1999–2000 Base Case EmissionsPM10 Emission Control Technology Summary Table

28. Case 1: Maintain 1999–2000 Base Case Emissions Summary Cost Table – Option 1

29. Case 1: Maintain 1999–2000 Base Case EmissionsEmerging Control Technology Cost Summary Table

30. State-of-the-Art Emission Control Technology Summary Table

31. Case 2 - State-of-the-Art Emission Control, Summary Cost Table

32. Regulation Timeline

33. Silver Lake Power Plant Emission ControlsReview Phase II