Centralia Power Plant BART-Like Control Technology Analysis

1. Centralia Power Plant BART-Like Control Technology Analysis Alan Newman, PE Washington State Department of Ecology

3. Why was the BART-like process done? • Response to requests from NPS, USFS, and EPA Region 10 to recognize Reasonably Available Control Technology decision as equal to or better than BART • Done by Ecology for inclusion in the SWCAA’s RACT Order Technical Support Document • The RACT technology review was in response to a SWCAA request for the plant to evaluate and implement emission controls to reduce the air quality impacts of the plant.

4. Brief history • Permitted in 1969 for construction • Unit 1 on line in 1972, Unit 2 in 1972 • Initial operational problems with particulate controls limited generation to less than full design rate • Particulate problems fixed but new coal field increased SO2 causing continuing operational limitations until company could address

5. Plant description • 2 B&W tangentially fired dry bottom pulverized coal boilers • Steam turbines rated at 1440 MWe, boiler limited to 1404 MWe • Mine mouth plant designed for Centralia coal field’s sub-bituminous coal • At full production, uses about 6.5 million tons of coal per year, Powder River Basin provides coal that the mine can’t produce

6. Initial Design criteria for Plant

7. 1988/89 Control Technology Analysis • Required to look at plant solutions for measured stack and ambient SO2 violations • Concluded that no cost effective SO2 or NOx control existed to implement at the plant

8. Plant Emissions Before RACT

9. 1995 RACT Analysis • Required by local air pollution control authority to comply with state law • Established SO2 limit at Acid Rain Allowance level (55,000 tpy) • Did not address other pollutants • RACT Order appealed • Conclusion that RACT limit did not protect human health • SWCAA repealed the order setting stage for negotiated process and final RACT report and Order

10. Collaborative Decision Making Process • Year long negotiation process involving Pacific Corp, the rest of the owners and • Used a facilitator/mediator to move the process along

11. Ground Rules Of The CDM Negotiations • Result would not cause plant to close • Accepted NPS visibility impacts modeling • Agreed plant subject to BART based on unit age and emissions • Agreed that a an attribution of visibility impacts would not be done • Goal would be to minimize visibility impacts based on the NPS monitoring

12. Visibility Evaluation by NPS [1] 2/24/95 National Park Service comment letter on Draft 1995 RACT Order Estimated as the PTE for the plant

13. Technology Evaluation • 74 different SO2 control techniques evaluated • 37 different NOx control techniques evaluated • Lists included experimental technologies which would remove SO2 and NOx • PM/PM10 emission limits based on series ESPs would be evaluated

14. Types Of SO2 Technologies Evaluated • Experimental • Chemical recovery technologies • Joint SO2 and NOx removal technologies • Conventional • Multiple vessel configurations • Single vessel configurations • Lime and limestone based • Ammonia based • 100% PRB coal • Conversion to natural gas

15. Criteria to Shorten List • Only available technologies • Meets emission limits from the CDM negotiation • Used on coal fired powerplants • At least as effective in reducing pollutant as controls installed • Technical feasibility • Does not generate safety hazards at plant • Minimal adverse impact on salability of by-products

16. Technologies Evaluated In Detail

17. Common Characteristics • By products would be marketable • No changes to wastewater discharge permits required • No or minimal hazardous waste generated • Took advantage of 20+ years of FGD technology and reliability improvements by minimizing component count • Reduced modeled visibility impacts to 2 days or less impacted per year

19. Selected SO2 Technology • LSFO FGD system • 1 ball mill for both FGD vessels • 1 FGD vessel per boiler • 1 common FO/clarifier unit • Gypsum sold for wallboard • Cost effectiveness of $250 – 300/ton • Emission limit of 10,000 ton SO2 per 12 month period

20. Selected NOx Control Technology • Combustion Controls • Low NOx burners • CCOFA • SOFA • Cost effectiveness of $113 – 233/ton • Emission limit of 0.30 lb/MMBtu

21. PM/PM10 Control • No technology changes seriously evaluated • Some changes considered as part of adding Lime Spray Drier controls • Review supported PM limit of 0.010 grains/dscf to include effects of selected FGD process

22. Effects of Selected Controls • Reduced modeled visibility impacts to 2 days or less impacted per year • Did not affect salability of collected fly ash for pozzolan • Gypsum produced is salable for wall board • Fits the plant site • Did not generate a hazardous waste of require NPDES permit to be modified

23. Ambient Air Quality Impacts • No modeled SO2, NOx, PM, or ozone impacts to NAAQS due to selected controls • Visibility impacts at or below the 2 days per year target rate • A health effects study performed as part of the RACT process • Study focused on populated areas (Seattle area) • Emissions reduction would result in large mortality reduction • Showed small impact on mortality due to remaining emissions

24. BART like analysis • Evaluation done by Ecology for inclusion in SWCAA support document • Done to support inclusion of the SO2 and NOx limitations in the SIP • Followed process in the 1980 BART for fossil fueled electric generating plants guidance • Used the RACT technical evaluation for its base • Included a comparison to the NSPS limits

25. Legal Results Of Process • One person appealed the results of the RACT process numerous times • Contended that public health from SO2 impacts not protected • Health effects study supported RACT decision • Courts supported SWCAA process and decision in the final RACT order at every appeal

26. Financing and Tax Aspects of Project • Capital costs estimated at $250,000,000 (final costs about $200,000,000) • Owners insisted that project needed tax breaks to make economically feasible • Went to legislature to get sales and property tax relief on new control equipment • Tax relief law passed second time proposed • contained the RACT SO2 emission limit • “banked” certain sales taxes while construction underway • Releases banked taxes once plant met emission limits • Contains tax penalty if emission limit not maintained • Contained requirement to educate plant and mine workers of owners chose to close plant rather than install controls

27. Phase 1 Visibility SIP • Contains Centralia RACT limits for SO2 and NOx as part of reasonable progress

28. Centralia Emission Limits