1. Southern Company Biomass Co-firing Research

2. Doug Boylan & Steve Wilson Southern Company Bill Zemo Alabama Power Kathy Russell Georgia Power Southern Company Participants

3. Switchgrass Co-firing Sponsors and Participants Southern Company Auburn University EPRI Southern Research Institute Wilson Farms Sunbelt Expo U.S. DOE McBurney

4. Plant Staff Gadsden and Mitchell

5. Co-milling - mix biomass with coal and introduce into the furnace through the coal handling system Simple procedure Reduced capital cost Reduced transport cost Considerable system experience Direct injection - introduce ground biomass pneumatically into the furnace through dedicated burners Higher co-firing percentages Direct biomass control Biomass Co-firing Technologies

6. Co-Milling Switchgrass and Coal Coal does not flow when mixed with low percentages of grass

7. Pellet Co-firing – Potential Advantages Improved efficiency Reduced plant capital Reduced transportation Reduced labor Reduced dust

8. Cubing Setup - Switchgrass farm in Lincoln, AL

9. Cubes sensitive to Moisture Binder type and percentage Grass type and rate

10. Mitchell – Cube Combustion One week of testing completed Cubes handle and burn fairly well Serious bunker issues – Rat-holing

11. Tub grinder Metering Bin Transport Fan 3 Levels of coal at each corner Boiler Pneumatic Transport Lines Upper Grass Burner Lower Grass Burner (not connected) Switchgrass Bales Upper Grass Burner Switchgrass Co-firing Schematic

12. Gadsden – Co-Firing Facilities

14. (Full Load - 7% by heat input) Switchgrass Co-firing and Boiler Efficiency

15. Cement and Ash Tests ASTM specifications exclude biomass ash with coal ash for cement Conducted tests with University of Alabama in Birmingham to evaluate effect of wood ash on cement properties Coordinating efforts with ASTM

16. SCR Catalyst Effects SCR (Selective Catalytic Reduction) is NOx emission control device Catalyst is affected by biomass ash Pilot study at Plant Gadsden with EPRI

17. Grass Co-Firing Energy Cost Present

18. Grass Co-Firing Energy Cost Future

19. Conclusions 1.Direct injection with grass was technical success 2.Co-firing reduced emissions, but was a little less efficient 3.Cubes have problems 4.Grass co-firing cost predictions were about 2.6¢/kWh to 3.0¢/kWh higher than coal power 5.Results suggest a subsidy will be required to make grass co-firing viable for an RPS 6.Biomass cannot be co-fired at some units for technical and cost reasons at this time 7.Research is on-going at Southern Company to address these issues

20. Questions?