1. Indigo Agglomerator Reducing Particulate Emissions & Reducing Opacity

2. Agglomerated Particles

3. Agglomerator Is Like An ESP • Grounded plates • Discharge electrodes • Alternating arrangement • High voltage energization • Low pressure drop

4. Agglomerator Is Not Like An ESP • No collection • No hoppers • No rappers • High velocity / small size • +/- high voltage • Low power consumption

5. THE INDIGO AGGLOMERATOR

6. THE BENEFITS • Reduced mass emissions • Reduced visible emissions • Greater compliance safety margin • Increased choice of fuel supply • Higher tolerance for • Boiler upsets • Lost electrical sections of ESP

7. Tarong Power Plant -Australia

8. Mississippi PowerPlant WatsonUnit 4

9. Mississippi Power - Plant Watson Agglomerator Lift In Place

10. Watson ESP Outlet Tests Emerald Coal April 2004 • MEASUREMENTA PASSB PASSREDUCTION • OPACITY % 13.2 2.3 83% • PARTICULATE • Grains/Act. Cubic Ft. 0.0136 0.0082 40% • FLOW • Actual Cubic Ft/Min 443 609 406 455

11. Watson ESP Outlet Tests Method 17West Elk Coal – April 2003 • MEASUREMENTA PASSB PASSREDUCTION • OPACITY % 15 4 73% • PARTICULATE • Grains/Act. Cubic Ft. 0.012 0.0066 45% • Milligrams/Cubic Meter 27.5 15.1 • FLOW • Actual Cubic Ft/Min 408 718 450 700 • Actual Cubic Meters/Min 11 573 12 762 • GAS TEMPERATURE • Degrees F. 276 273 • Degrees C. 136 134

12. Drummond Sub Micron Particles

13. OPACITY TREND AT PLANT WATSON

14. A Precipitator B Precipitator Voltage (kV) Current (mA) Voltage (kV) Current (mA) Percentage Increase in Current Before Agglomerator 52.4 217 52.6 230 5.8% After Agglomerator 55.0 230 55.0 330 43.5% Percentage Increase 5.0% 6.0% 4.6% 43.8% INLET FIELD ELECTRICAL IMPROVEMENT

15. A Precipitator B Precipitator Voltage (kV) Current (mA) Voltage (kV) Current (mA) Percentage Increase in Current Following Installation Agglomerator 51.6 1197 52.8 1106 0.8% Before Shutdown Agglomerator 48.8 460 54.8 888 93.0% Percentage Increase -5.4% -58.1% 3.8% -19% OUTLET FIELD ELECTRICAL IMPROVEMENT