“Enhanced Plant Performance via Effective SO 3 Control” Sterling Gray, URS Corporation Mick Harpenau, Duke Energy EUEC Conference Phoenix, AZ February 3, 2010

2 SO 3 Adversely Impacts … Heat Rate Air Heater Reliability NOx Removal Mercury Capture CO 2 Emissions Equipmen t Corrosion

3 Impact on Corrosion Potential

4 Air Heater Fouling Ash Sulfuric Acid Ammonium Bisulfate Source: Alstom Airpreheater Company

5 Impact on Heat Rate

6 Impact on CO 2 Emissions

7 Impact on NOx Control Increase SCR NOx Removal –limit ABS formation via SO 3 reduction –permit operation at elevated NH 3 slip Extend Useful Life of Catalyst –elevated slip permits lower reactor potential Extend Low-Load Operation of SCR –reduce SO 3 level at SCR inlet –lower Min Op Temp (min load) Strategy can be Applied to SNCR

8 Impact on NOx Removal

9 Impact of SO3 on ACI Performance Source: EPRI

10 Impact on Hg Capture in Ash

11 Impact on Hg Removal with ACI Source: EPRI, Mercury Research Center, March 2007

12 Comparison of SO 3 Controls

13 SBS Injection™ Technology Features Patented Technology Simple Solution Injection Sodium-Based Reagent Dual-Fluid Atomization Selective Reactions High SO 3 Removal Low Injection Rate Product Collected with Ash Benefits Opacity Elimination Corrosion Reduction ESP Enhancement HCl and Se Removal Potential Heat Recovery SCR/SNCR Flexibility Hg Capture Enhancement CO 2 Reduction Maximum Benefits with “Upstream” Injection

14 Simplified SBS Flow Diagram

15 SBS Injection Locations SCR Outlet Air Heater Outlet SCR Inlet

16 SBS Injection Installations 12,500 MW Installed on 20 Boilers

17 SCR First Catalyst Layer SBS Injection Lances (Par Mixers removed) Ammonia Injection Grid Economizer Outlet TurboMixers Gibson “Pre-SCR” Injection

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19 Gibson SO 3 Test Results Baseline SBS Injection

20 SCR Min Op Temp vs SO 3 Δ MOT ~ 80°F Baseline – 615°F With SBS – 635°F Composite Range of MOT Information Provided by Catalyst Suppliers

21 Summary SO 3 Adversely Impacts Plant Performance –Corrosion –AH Fouling –Heat Rate –CO 2 Emissions –NOx Removal –Mercury Capture SO 3 Removal can Generate Millions $ in Benefits –Avoided Forced Outages –Fuel Savings –Lower Environmental Compliance Costs SBS Injection Offers Cost-Effective SO 3 Control –Treats upstream of SCR / AH –Very high SO 3 removal (~98%) –Proven - 20 units - 12,500 MW – 7 yrs SO 3 Removal: It’s not just for “Blue Plume” anymore SO 3 Removal: It’s not just for “Blue Plume” anymore

22 Questions?