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# OAR Box 1781 Prepped by Ollie Stewart



# Document

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# 26)11-1-1 8

Docket Number: 

# A-90-3 7

Printed 10/29/2008 10:46:19 AM Sheet 26 of 142

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89-72. 1 89-72. 4



### EXPERIENC E WITH TOP-DOW N BACT POLIC

Y

CYNTHI A A . SOUL E

CIT YPUBLI C SERVIC E SA N ANTON10 / TEXA S



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A I R& WAST EMANAGEMEN T ASSOCIATIO N

a > SlNC C 190 7



# Fo r Presentatio n aI th e 82n dAnnua l Meetin g & Exhibitio n Anaheim , Californi a Jun e 25-30 , 198 9 INTRODUCTION Th e determinatio no f Bes t Availabl e Contro l Technology (BACT ) i s a majo r face t o f the Preventio no f Significan t Deterio ratio n(PSD ) Program , whic hcam e abou t a s a resul t o f the Clea n Ai r Ac t Amendment s o f 1977 . I nfact , th e Amendment s redefine d th e wa y federa l permit s wer e issue d fo r th e constructio no f facil itie s whic hhav e the potentia l t o contribut e significantl y t o ai r pollution . Th e BAC T review

proces s remaine d relativel y unchange d fro

m it s inceptio nunti l Decembe r 1987 , whe nth e EP A announce d a ne

w "Top-Down " review polic y

fo r BACT . Thi s polic y ha s bee nthe sourc e o f confusio nan d controvers y

amon g PS D permi t applicants , includin g electri c utilities . Cit y Publi c Service , an-electri c utilit y i nSa nAntonio , Texa s (EP

A Regio nVI) , foun d the polic y

t o b e a sourc e o f frus tratio nwhic hresulte d i nmonth s o f negotiation s wit hth e EP A ove r it s PS D permi t fo r a coal-fire d powe r plant . Th e permi t wa s submitte d i nNovember , 1987 , on e mont hbefor e th e Top-Dow npolicy wa s issued . Th e tota l permi t review require d 1 1 month s t o com- - plet e and th e PS D permi t wa s issue d o nSept . 30 , 1988 . A s a resul t o f th e Top-Dow npolicy , som

e permitte d level s fo r the ne w 525-megawat t utilit y boile r wil l b e bette r tha nNe w Sourc e Per formanc e Standard s (NSPS ) levels . I nthi s paper , th e effort s undertake nb y CP S i npreparing it s PS D permi t ar e describe d a s wel l a s CPS 1 response s t o re quest s fo r additiona l informatio nmad e b y EP A Regio nV I unde r th e Top-Dow

npolicy . Ther e i s als o a descriptio no f th e pollutio n contro l equipmen t selecte d b y CP S t o mee t th e permi t requirement s negotiate d betwee nCP S an d Regio nV I EPA . A descriptio no f the ne w Top-Dow

npolic y

and som

e draf t polic y guideline s i s provide d a s wel l a s a discussio no f som e o f th e controvers y

surroundin g the policy' s interpretation . A brie f discussio no f BAC T a s i t i s define d and interprete d i nthe PS D regulation s i s presente d first . Fo r a mor e complet e understanding o f ho w an d wh y the PS D progra

m develope d and a nexplanatio no f relate d ai r qualit y regulations , a novervie w o f th e Clea nAi r Ac t i s provide d i nthe Appendix . BES T AVAILABL E CONTRO L TECHNOLOGY Unde r th e PS D provisions , determination s o f bes t availabl e contro l technolog y (BACT ) ar e require d fo r th e majo r sourc e bein g permitted . BAC T i s define d inthe PS D regulation s at 4 0 CFR 52.2 1 (a)(11 ) a s "anemission s limitatio n...base d o nth e maximu

mr "

89-72. 4 89-72. 4

degre e o f reductio nfo r eac hpollutan t subjec t t o regulatio n unde r (the ) Ac t whic hwoul db e emitte dfro m an y propose d majo r stationary

sourc e o r majo r modificatio nwhic hth e Administrator , o na case-by-cas e basis , takin g int o accoun t energy , environ menta l an

deconomi c impacts , an dothe r costs , determine s i s achievabl e fo r suc hsourc e o r modificatio nthroug happlicatio no f productio nprocesse s o r availabl e methods, system s and tech niques..." 1 A s indicate db y th e definition , BAC T analyse s ar e t o b e mad e o na case-by-cas e basis , an dsource-specifi c factor s suc h a s loca l energy , environmenta l o r economi c condition s ar e t o b e considered . BAC T i s require dfo r al l emission s o f an y pollutan t emitte d abov e significanc e level s (se e Tabl e I A i nAppendix) , whic h includ e criteria , non-criteri a an dnon-regulate d (bu t potentiall y toxic ) pollutants . Criteri a pollutant s ar e thos e fo r whic ha Nationa l Ambien t Ai r Qualit y Standar d(NAAQS ) ha s bee nestab lished . Non-crltcri a pollutant s ar e thos e whic har e controlle d b y regulatio nothe r tha nNAAQS . Pollutant s whic har e totall y non regulate dma y

als o b e include dinBAC T analyse s i f ther e ar e regulate dpollutant s bein g considered , accordin g t o a nEP A polic y directiv e issue dt o th e regiona l office s i nSeptembe r 1987 , i n whic hEPA

responde dt o concern s abou t ai r toxi c emission s fro m municipa l wast e incinerators 2

. I t i s importan t t o not e tha t th e legislativ e languag e mandatin g th e establishmen t o f New Sourc e Performanc e Standard s (NSPS ) i s ver y

simila r t o th e languag e whic hdefine s BAC T i nth e PS D regulations . I nSectio n11 1 (a ) o f th e Clea nAi r Ac t a stan dardof

_performanc e selecte da s NSP S wa s intende d t o reflec t th e applicatio no f th e "bes t technologica l system o f continuou s emissio nreduction " takin g int o consideratio nth e cos t o f achiev in g tha t emissio nreduction , an d"an y nonai r qualit y

healt hand environmenta l impac t andenerg y requirements." 3 Thus , th e standard s hadt o reflec t th e bes t demonstrate d contro l practice , adequatel y

considerin g th e cos t o f suc hcontro l and al l varia tion s o f operatin g conditions . Determinatio no f th e degre e o f emissio nreductio nachievabl e wa s largel y base do nresult s o f emission s test s fro m wel l controlle dexistin g sources . Historically , th e BAC T analysi s a s presente di nth e permi t applicatio nha s bee na nanalysi s an dcompariso no f th e curren t contro l technologie s availabl e fo r th e particula r sourc e bein g permitted . Th e analysi s woul dfirs t presen t the leve l o f control , optio nrequire dt o mee t NSP S generall y a s th e bas e case . The n alternativ e system s woul db e describe dtha t coul d achiev e com plianc e wit hNSP S o r bette r tha nNSP S an dthes e alternative s woul dbe compare dt o th e bas e case . Sinc e BAC T contro l canno t b e les s stringen t tha nth e appli cabl e federa l NSPS , n o analysi s woul dconside r an y limi t greate r tha nNSPS . However , whe nperformanc e standard s wer e bein g de veloped , a s state d previously , economic , environmental , an d energy impact s wer e eac hconsidere d fo r th e particula r source . Th e bes t demonstrate d contro l practice , base d o nemissio ntest s o f existin g facilities , wa s use da s a basi s fo r NSPS . Sinc e EPA' s developmen t o f NSP S standard s considere d th e ver y element s require dunde r th e BAC T process , meetin g NSP S ha s generall y bee n take nt o b e a nadequat e demonstratio no f BACT . Thi s equatin g o f BAC T wit hNSP S wa s specificall y eliminate d b

y th e Top-DownBAC T policy . LICENSINGPROGRA

M FORJ.K . SPRUC E

I nlat e 1986 > cit y Publi c Service , th e municipa l electri c utilit y

whic hserve s th e cit y o f Sa nAntonio , Texa s and sur roundin g areas , bega nintensiv e environmenta l assessmen t wor k i n preparatio nfo r licensin g tw o 525-megawat t wester ncoal-fire d powe r plants . Extensiv e environmenta l studie s wer e undertake ni n orde r t o provid e baselin e dat a fo r preparatio no f all.necessar y permit s an d license s fo r th e plants . Th e investigation s and survey s too k ove r a yea r t o complet e an d cos t i nexces s o f $ 1 million . Ai r permittin g cost s wer e abou t one-thir d thi s amount . Th e ne w

plant , calle d J.K . Spruce , i s t o b e buil t adjacen t t o fou r existin g powe r plant s - two natura l ga s and tw o wester n coa l unit s a t Calavera s Lake , approximatel y 1 3 mile s southeas t o f Sa nAntonio . Th e existin g coal-handlin g facilitie s wil l b e modifie d t o accommodat e th e expande d generatin g capacit y whic h woul dus e th e sam e fue l source . Th e fue l i s lo w sulfur , sub bituminou s coa l fro m the Powde r Rive r Basi ni nWyoming . A chronolog y

o f event s i nth e ai r permittin g proces s i s provide d i nTabl e I . Permi t applicatio npreparation , whic hbega n i nJanuar y

o f 1987 , involve d collectio no f ambien t ai r qualit y dat a an

d climatologica l dat a whic hwer e t o b e use d i ndispersio n analysi s modelling . Additionally , preliminar y desig ninformatio n relatin g t o emission s fro m th e propose d facilit y wer e needed . Sinc e permittin g necessaril y precede d detaile d desig nengineerin g work , initia l permittin g wa s conducte d o nthe basi s o f a surrogat e facilit y whic hver y

conservativel y

represente d th e propose d fina l design . Importan t desig nfeature s o f th e surro gat e facilit y

include d anestimatio no f size , fue l bur nrate , fue l quality , stac k height , stac k diameter , exac t locatio nan d coa l yar d design . A s fina l desig ndat a becam e available , th e conservativ e natur e o f th e surrogat e parameter s becam e obvious .

Compute r dispersio nmodellin g mus t b e performe d inorde r89-72. 4 89-72. 4

Tabl e I . Chronolog y o f Event s - Ai r Permittin g

Decembe r 198 6

Jan.-Oct . 198 7

Nov . 5 , 198 7
Dec . 1 , 198 7

Marc h8 , 198 8

Marc h9 , 198 8 Apri l 26 , 198 8

May 16 , 198 8 Jul y 1 , 198 8

Jul y 14 , 198 8

Sept . 30 , 198 8 Environmenta l studie s begi ni nsuppor t o f permittin g Permi t applicatio npreparation , dat a collection , modellin g efforts , meeting s wit hTACB . PS D applicatio nsen t t o TAC B Crai g J . Potte r memorandu m sen t t o regiona l EPA office s
EPA informe dCP S o f nee dfo r a mor e in-dept hBAC analysi s CP S bega nadditiona l BAC T studie s BAC T Suppor t Study presente dt o EP

A Draf t PS D Permi t receive d fro m TAC B
EP A sen t TAC B thei r comment s o ndraf t PS D permi t requestin g mor e BAC T information . CP S me t wit hEP

A t o discus s thei r comment s an d supplie dSupplementar y BAC T Informatio n PS D Permi t grante db y EPA t o determin e complianc e o f th e new sourc e wit hth e NAAQ S an dPS D incremen t levels . CPS ' modellin g wa s performe d a t maximu m operatin g level s inorde r t o determine.impact s base d onwors t cas e conditions . Th e modellin g methodolog y wa s th e subjec t o f severa l earl y

meeting s wit hth e Texa s Ai r Contro l Boar d(TACB ) an d the EP

A and thos e meeting s eliminate d potentia l source s o f modellin g problem s late r i nth e process . Preliminar y modellin g wa s performe d t o determin e th e are a o f impac t fo r al l pollutant s emitte d i nsignifican t quantities . Then , regiona l emissio n inventorie s wer e obtaine dfo r thes e pollutants . Projec t review

meeting s wer e hel d wit hth e TAC B severa l time s in198 7 t o discus s th e permittin g strateg y an d the model lin g approach . Th e TAC B ha s partia l delegatio no f th e PS D permi t progra m bu t EP

A Regio nVI mus t approv e an d issu e the fina l PS D permit . Th e fina l PS D permi t applicatio nwa s submitte d i nearl y November , 198 7 t o the TACB , and late r t o th e EP A afte r i t wa s declare d administrativel y complet e b

y th e TACB . Th e BAC T portio no f th e PS D permi t describe d th e contro l technology

fo r th e ne

w unit s t o b e th e following : fabri c filter s for contro l o f particulat e matter , we t limeston e scrubbe r syste m for contro l o f sulfu r dioxide , an d a combinatio no f combustio n contro l technique s an d furnac e desig nfo r contro l o f nitrou s oxid e emissions . A combinatio no f dus t collector s an d we t sup pressio nwoul d b e use d for th e coal , as handlimeston e handlin g systems . Tabl e I I describe s th e alternativ e technologie s whic h wer e considere d for BAC T andTabl e III . provide s a descriptio no f th e BAC T whic hwa s ultimatel y chose nfo r th e ne w plant . Th e chose ntechnologie s woul d mee t th e Ne w Sourc e Performanc e Stan dard s (NSPS ) fo r Electri c Utilit y Steam Generatin g Unit s buil t afte r Sept . 197 8 whic har e describe d i n4 0 CF RPar t 60 , Subpart s A an dDa , Subpar t Yfor Coa l Preparatio nPlants , an dSubpar t OO O for Non-Metalli c Minera l Processin g Plants . Th e BAC T portio no f th e permi t wa s a conventiona l analysi s o f the variou s contro l alternative s obtaine d fro m literatur e data , technica l an d engineerin g journal s an d textbooks , infor matio nfro

m boile r an

d scrubbe r manufacturers , othe r PS D permi t application s an

dEnvironmenta l Impac t Statement s fro m othe r coal fire d plants . A

revie w o f previousl y

submitte d permi t applica tion s als o helpe d determin e th e forma t an d conten t o f the study . TOP-DOW N BAC T POLICY O nDecembe r 1 , 1987 , J . Crai g Potter , Assistan t Administra tor fo r Ai r an

d Radiatio na t th e EPA , wrot e a memo t o al l Region al Administrator s recommendin g a new "Top-Down " approac ht o BAC T analysis . I t wa s describe d a s "th e determinatio no f th e sos t89-72. 4 

### r

89-72. 4 Tabl e II . BAC T Contro l Technologie s Pollutan t Selecte d BAC T Contro l Technolog y Alternative s Considere d

Particulate s

Sulfu r Dioxid e

Nitrou s Oxid e Carbo nMonoxid e Volatil e Organi c Compound s Fabri c Filte r

We t limeston e Scrubbe r (FGD ) Syste m

Combustio ncontrols , typ e o f boile r

Tabl e III .

A/ C rati o (Gross ) No . o f bag s Clot hare a Gas ' flo

w rat e Typ e o f bag s Temperatur e Min/Ma x Typ e o f cleanin g Soni c horn s

Typ e Remova l efficienc y

Ho . o f absorber s

Manufacture r Typ e Control G Electrostati c Precipitato r Spray drye r Dua l alkal i Wellman-Lor d Magnesiu

m oxid e Fluidize d be d combustio n Selectiv e catalyti c reductio n Selectiv e non-cata lyti c reducti c Flue-ga s recircula tion Wate r injectio n Reburnin g
Desig nContro l Technologie s
FABRI C FILTE R 1.35 : 1 13,44 0 i n2 8 compartment s 1,335,39 8 ft 2 1,805,43 5 acf m

(a t 28 5 F ) Teflo nFinishe d fiberglas s 23 5 t o 50 0 F Revers e ai r Tw o pe r compartmen t SCRUBBE R
We t limeston e scrubbe r 70 % overall ; 90 % remova l fo r 77.8 % o f flu

e gas;remaindo r by-passe d fo

r reheat . 3 ( 2 i noperation , 1 spare )
BOILE R Combustio nEngineerin g Tangential-fired , dr y bottom Overfir e air , concentri c tiring stringen t contro l availabl e fo r a simila r o r identica l sourc e o r sourc e category" , an d th e demonstratio ntha t thi s leve l o f con tro l i s "technicall y o r economicall y

infeasibl e fo r th e sourc e i n question." 4 I f thi s demonstratio ni s done , th e nex t mos t strin gen t leve l o f contro l woul d b e evaluate d unti l th e BAC T leve l unde r consideratio n"canno t b e eliminate d b y an y substantia l o r uniqu e technical , environmenta l o r economi c objections." 4 Th e memo goe s o nt o stat e tha t th e approac hdiffer s fro m othe r anal yse s i ntha t "i t require s th e applican t t o analyz e a contro l technology

onl y i f th e applican t oppose s tha t leve l o f control ; th e othe r proces s require d a ful l analysi s o f al l possibl e type s an d level s o f contro l abov e th e baselin e case." 4

Severa l draf t Guideline s fo r Top-DownBAC T hav e becom e availabl e throug hvariou s regiona l EP A offices . Tw o o f thes e wil l b e describe d briefly . Draf t "Guideline s fo r Determinin g BAC T unde r th e Top-DownApproach " wa s distribute d a t a nApri l 14 , 198 8 meetin g a t EP A Regio nI V

offices . Anothe r guidelin e - currentl y

bein g considere d b y EP A a s a nappropriat e an d usefu l interi m guidanc e documen t i s th e Northeas t State s fo r Coordinate d Ai r Us e Managemen t (NESCAUM ) BAC T Guidelines . Th e firs t ste p suggeste d i nth e Regio nIV guideline s i s t o • identif y

th e mos t stringen t technicall y viabl e contro l alter natives , wit hcategorie s o f control s being : existin g contro l technology

(prove ni npractic e o r require d b y a-permi t fo r sourc e category) , technicall y feasibl e alternative s (demonstrate d i n practic e o nothe r sourc e categories) , innovativ e contro l technol og y (neve r applie d t o an y sourc e bu t whic hcoul d b e technicall y applied) , an

d productio nprocesses , fuels , and material s tha t ar e inherentl y

les s polluting. 5 Th e NESCAU M Guideline s ad d tha t n o technicall y

feasibl e alternativ e shoul d b e rule d ou t an d tha t th e applican t shoul d no t simpl y revie w

existin g control s fo r th e sourc e categor y

i nquestio nbu t loo k a t simila r categorie s an d innovativ e contro l technologies. 6

Th e mos t stringen t contro l technolog y "i s assume d t o b e BACT , unles s th e applican t demonstrate s vi a a cas e specifi c analysi s th e infeasibilit y o f th e contro l optio nbase d onuniqu e projec t specifi c mitigatin g factors." 5 I njustifyin g a les s stringen t contro l option , th e guideline s sugges t tha t th e contro l option s b e ranke d i nterm s o f stringentness , wit hcontro l option s mos t stringen t ontop , followe d b y a discussio no f th e variou s impact s o f eac hcontro l option , includin g contro l efficiency , economic , environmenta l an d energy

impacts . Th e mos t stringen t contro l alternativ e i s assume d t o b e BAC T unles s th e applican t ca ndemonstrat e tha t i t i s infeasible. 5 Th e proces s i s continue d for eac hleve l o f contro l unti l th e applican t demonstrate s BAC T for hi s facility . Example s o f uniqu e factor s considere d



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appropriat e inevaluatin g th e infeasibilit y o f the mos t stringen t contro l optio nar e a s follows : technica l infeasibility , othe r environmenta l impacts , energ y penalties , and economi c impacts . Th e burde no f proo f fo r applyin g a les s stringen t contro l technolog y

remain s i nth e applicant' s "cas e specifi c evaluatio n o f th e contro l alternatives. " 6

Du e t o the man

y interpretation s o f th e Potte r memo , ther e ha s bee nconfusio na s t o th e correc t metho d fo r makin g BAC T determinations . Some EP A region s apparentl y ar e equatin g BAC T wit hLowes t Achievabl e Emissio nRat e (LAER ) accordin g t o a lette r date dAug . 17 , 198 8 t o Mr . Donal dClay , EPA' s Actin g Assistan t Administrato r o f Ai r andRadiatio nb y th e la

w fir m o f Hunto nand Williams , representin g th e Utilit y Ai r Regulator y

Grou p (UARG) . Fo r example , th e lette r state s tha t Regio nI Xha s issue d a BAC T guidanc e documen t tha t adopt s a tes t fo r determinin g BAC T tha t focuse s "almos t exclusivel y onth e financia l abilit y o f th e owne r o r operator" , an

drequire s tha t th e mos t stringen t contro l technolog y

- LAE R- b e installe di f th e owne r o r operato r ha s th e financia l abilit y t o pa y

fo r it. 7 Th e lette r argue s tha t "Wher e th e environmenta l benefit s o f additiona l control s ar e negligibl e bu t th e economi c o r energ y cost s ar e significantl y greate r tha n othe r system s o f control , th e Clea nAi r Ac t doe s no t requir e applicatio no f th e mos t stringen t contro l system." 7

DEVELOPMEN T O F ADDITIONA L BAC T STUDIE S I N RESPONS E T O EP

A
A s a resul t o f CPS ' meetin g wit hEP A Regio nV I i nearl y Marc ho f 1988 , th e impac t o f Potter' s Top-Dow nmem o becam e ap parent . Th e EP

A requeste dgreate r detai l i nthe BAC T analysi s beginnin g wit hbette r tha nNSP S level s for contro l o f parti culate , sulfu r dioxid e an dnitrou s oxides . On e particula r West er ncoal-fire dplan t wa s mentione dwhic hha dbee npermitte d fo r a 0.0 2 lb/MMBT Uleve l fo r particulat e matte r an d CP S wa s questione d a s t o wh

y they shoul dno t mee t thi s level , rathe r tha nthe NSP S leve l o f 0.0 3 lb/MMBTU . EPA indicate dtha t they had obtaine d thi s informatio nfro m th e EPA' s BACT/LAE RClearinghous e document , whic hprovide s recen t dat a o ncontro l technolog y determination s an demissio nlimit s b y sourc e category . Th e Regio nrequeste dmor e detaile d informatio no nth e alternativ e contro l technologie s fo r sulfu r dioxid e (S0 2 ) an d nitrou s oxid e (NOx) , suc ha s th e rational e fo r choosin g we t ver su s dr y

scrubbing . Also , mor e detai l wa s requeste d o nalterna tive s fo r NO

xcontrol , specificall y selectiv e catalyti c reductio n (SCR ) an

d selectiv e non-catalyti c reductio n(SNCR) , technique s whic hhav e no t foun dextensiv e us e i ncoal-fire dutilit y plant s inth e U.S . bu t whic hhav e bee nuse di nsom e case s inEurop e an d Japan . Detaile deconomi c dat a fo r additiona l remova l efficienc y wa s als o requested . CP S immediatel y

prepare d a supplementa l BAC T documen t whic h focusedo

nth e economi c issue s raise d b y th e EPA . Th e 65-pag e BAC T Suppor t Study wa s complete d andsubmitte dt o th e EP A withi n tw o months , b

y th e end o f April , 1988 . Th e repor t examine d i n detai l th e cost s fo r alternativ e contro l level s fo r particulates , S0 2 , NOxan

d carbo nmonoxide . CPS ' preferre d technology'wa s use d a s th e bas e case , the n compare d wit halternativ e an d increasingl y

stringen t level s o f control . Thi s compariso nwa s primaril y technica l an

d economi c in nature , comparin g incrementa l cost s fo r additiona l contro l level s an d representin g th e result s i nterm s o f dollar s pe r to no f pol lutan t remove d o nth e basi s o f a 30-yea r levelize d cos t calcu lation . Energ y penaltie s an d othe r environmenta l factor s wer e als o compared . Fo r example , b y usin g a we t limeston e scrubber , fl y as h canb e collecte d separatel y and sol d a s a cemen t additive . Thi s i s th e curren t operatio na t CPS ' existin g coal-fire dplant , an d i t ha s resulte d i nsaving s an d royaltie s t o CP S o f u p t o $400,00 0 pe r year . I ncontrast , a lim e spra y

drye r system

woul dno t allo

w separat e collectio no f fl y as han

d s o woul d resul t i nlos s o f royalt y revenue s t o CP S a s wel l a s reguir e substantiall y greate r landfil l constructio nt o accommodat e additiona l wast e disposal . Anothe r exampl e o f environmenta l factor s describe dwa s the proble m wit hammoni a whic hi s use d i nSCRan d SNC Rtechnologies . Emission s o f unreacte d ammoni a ca ncreat e odo r problem s andca n als o contaminat e fl y ash , thu s preventin g it s sal e an d increasing soli d wast e problems . Uponfurthe r investigation , CP S discovere d tha t th e facilit y whic hth

e EP A ha d pointe d ou t a s havin g th e "top " level s o f par ticulat e contro l ha d actuall y neve r bee nconstructed ; thu s th e permitte d level s fo r tha t plan t coul dno t b e show nt o hav e bee n demonstrate d i noperation . Th e BAC T Suppor t Study differe d fro

m the permi t applica tion' s BAC T stud

y i ntha t BAC T impact s wer e evaluate d usin g ex pected o r averag e conditions . Normally , PS D permitte dimpacts , ar e base dupo na wors t cas e fue l analysi s an d100 % capacit y factors . CPS' s BAC T study result s reflecte dexpecte d o r averag e rathe r thanwors t cas e assumptions . Th e approac ho f usin g ex pected versu s wors t cas e condition s create d som e question s fro

m th e EP A intha t expecte demission s fro m the plant , base dupo n averag e conditions , woul d be significantl y les s tha npermitte d condition s whic har e base dupo nwors t cas e assumptions . I nfact ,

1 089-72. 4 89-72. 4

expecte demission s woul db e 2 5 t o 30 % les s tha npermitted , wors t cas e conditions . Th e wors t cas e level s ar e thos e whic hmus t b e proven - t o b e les s tha no r equa l t o thos e require d unde r NSPS . A fe w week s afte r the BAC T Suppor t Study wa s submitted , th e draf t PS D permi t wa s writte nb y th e TAC B and sen t ou t fo r com ments . Th e EP A

officiall y

responde dwit hthei r comment s t o th e TAC B o nth e draf t permi t onth e firs t o f July . Th e EP A comment s reiterate dth e same concern s abou t th e BAC T analysis , tha t ther e wa s stil l no t sufficien t justificatio nfo r no t meetin g th e "top " leve l o f 0.0 2 lb/MMBT Ufor particulat e matter , no r th e bette r tha nNSP S level s fo r SO 2 an dNOx . Mor e informatio nonenergy and environmenta l impact s t o justif y th e highe r emissio nlimi t wa s requested . Some aspect s o f th e BAC T Suppor t Study previousl y

submitte d wer e discusse di nth e EP A comments , suc ha s margina l versu s averag e costs . CPS ' positio nwa s tha t th e economi c compariso n betwee nth e bas e cas e an dth e mor e stringen t contro l case s shoul d b e don e o na nincrementa l o r margina l cos t basis . Thi s analysi s mean s tha t remova l cost s ar e expresse di nterm s o f additiona l o r incrementa l cost s divide db y th e additiona l ton s removed . Thi s incrementa l cos t shoul dthe nb e judge dagains t th e bas e cas e an d compare dt o th e environmenta l benefit s whic hmigh t accrue . How ever , sinc e CP S wa s abl e t o demonstrat e compelling , noneconomi c rationale s fo r selectin g it s chose ncontro l equipment , th e issu e "o f margina l versu s averag e cost s neve r becam e a seriou s issue . Soo nafte r receivin g th e comments , CP S me t wit hth e EP A t o reques t furthe r elaboratio no nthe additiona l informatio nbeing requested . At tha t meeting , an di na supplementar y BAC T documen t supplie dlater , i t .was determine dtha t uniqu e operatin g an d environmenta l impact s associate dwit hth e preferre d technologie s woul db e provide da s justificatio nfo r selecting.th e preferre d options . Tw o o f th e uniqu e factor s wer e tha t th e ne w uni t woul d be designe dfo r spee dcycling , a typ e o f operatio nwhic hcause s the loadt o swin g dail y durin g certai nmonth s o f th e year , causin g harshe r operatin g requirement s an demissio nvariation s whic h baseloa dunit s d o no t encounter . Anothe r facto r wa s tha t feature s o f the new

uni t woul db e replicatin g th e technolog y o f a nexist in g statio nwhos e operatin g level s wer e alread y documente d an

d coul db e use dt o determin e permitte dlevels . Wit hregar dt o particulat e matter , informatio nfro m an EPA/EPR I conferenc e o nparticulat e contro l technolog y wa s pre sente do nth e variabilit y o f fabri c filte r emission s an d the numerou s factor s whic haffec t baghous e performance , suc ha s coa l an d as hcharacteristics . Fo r example , on e facto r differentiatin g th e unit s bein g compare d wa s th e differenc e i ncoa l quality . Eve n thoug hth e two unit s bot hbur ncoal , on e burnin g a highe r BTU valu e coa l wit hlowe r as hconten t woul ddemonstrat e lowe r emissions . Th e fina l PS D permi t wa s issue do nSept . 30 , 1988 , eleve n month s afte r th e applicatio nwa s made . Th e fina l permi t term s resulte d i nreduction s fro m NSP S level s fo r sulfu r dioxid e an d opacity , bu t retaine d NSP S level s fo r NO xand particulat e matter . Sulfu r dioxid e emissio nlevel s wer e reduce d fro m th e NSP S leve l o f 0. 6 lb/MMBT Ut o 0. 5 lb/MMBT Uo na 30-da y rollin g average ; opacit y

wa s reduce d fro

m th e NSP S leve l o f 20 % t o 10% . CONCLUSIO N

A s a resul t o f EPA' s new Top-DownBAC T policy , a nextremel y thoroug hBAC T analysi s wa s performe d fo r a PS D permi t fo r a coal fire d powe r plan t i nTexas . A s a resul t o f intensiv e researc h an d continuou s negotiations , th e permitte e and agenc y wer e abl e t o reac hmutuall y satisfactor y

permi t levels , some o f whic hre sulte d i nlevel s mor e stringen t tha nNSP S fo r th e sourc e du e t o th e Top-Downpolicy . Top-downBAC T i s a new concep t whic hi s difficul t t o addres s becaus e o f th e lac k o f unified , specifi c guidanc e fro m th e EP A

t o determin e th e technica l feasibilit y o f specifi c contro l tech nologies . Thus , thoroug hresearc hint o th e chose ntechnolog y and rational e fo r selectin g i t i s recommende d prio r t o PS D appli catio nsubmittal . Earl y agenc y

contac t and negotiation s abou t contro l technologie s bein g considere d fo r th e permitte dsourc e wil l ai di npreparatio nfo r th e BAC T review . I naddition , a thoroug hrevie w

o f th e BACT/LAE RClearinghous e documen t an d othe r PS D permit s i s recommende d t o determin e previousl y permitte d level s fo r simila r sources .

1 189-72. 4 REFERENCE S

1 . Offic e o f th e Federa l Register , Nationa l Archive s and Record : Administration , Cod e o f Federa l Regulations . 4 0 CF R52.2 1 (a)(11) , Washington , D.C . (1987 )
2 . Emison , Geral dA. , Director , Offic e o f Ai r Qualit y Plannin g Standards , Memorandu m onImplementatio no f Nort hCount y Resourc e Recover y PS D Reman dt o al l Regiona l Directors , (Septembe r 25 , 1987) . 3 . Clea nAi r Act , Sectio n11 1 (a) . 4 . Potter , J . Craig , Assistan t Administrato r fo r Ai r and Radiation , Environmenta l Protectio nAgency , Memorandu m o n Improvin g Ne w

Sourc e (NSR ) Revie w Implementation , t o al l Regiona l Administrator s (Decembe r 1 , 1987 ) . 5 . Environmenta l Protectio nAgency , "Determinin g Bes t Availabl e Contro l Technolog y (BACT) : Th e "Top-Down " Approach , (marke d draft) , distribute da t EPA Regio nIV

office s o nApri l 14 , 1988 . 6 . Northeas t State s fo r Coordinate dAi r Us e Managemen t (NESCAUM) , NESCAUM BAC T Guideline , Octobe r 1988 . 7 . Field , Andre a B . et.al. , Hunto n& Williams , Correspondenc e t o Mr . Donal dClay , Actin g Assistan t Administrato r o f Ai r an dRadiation , U.S.Environmenta l Protectio nAgency , (Auqus t 17 , 1988) .



### NOT E T O EDITOR S

Unde r th e ne

wfedera l copyrigh t law , publicatio n right s t o thi s pape r ar e retaine d by th e author(s)

. 89-72. 4 APPENDI X OVERVIE W O F CLEA

N AI RAC T Sinc e i t wa s originall y passe d i n1955 , th e Clea nAi r Ac t (CAA ) ha s bee nth e majo r regulator y mean s o f protectin g huma n healt hand th e environmen t fro m source s o f ai r pollution. . Th e ac t wa s amende d significantl y i n197 0 and 1977 , an d i s currentl y undergoin g majo r review i nCongress . Th e CA A directe d EP

A t o delegat e authorit y t o th e individua l state s t o implemen t thei r ow nprogram s fo r ai r pollutio ncontrol . Eac hstat e mus t demonstrat e tha t it s progra m i s equa l t o o r mor e stringen t tha nth e federa l progra m befor e th e stat e ca nb e grante d fina l authority . Provision s o f th e CA A ar e carrie d ou t b y th e EP A

throug henforcin g regulation s whic hinclud e th e fol lowing : Nationa l Ambien t Ai r Qualit y Standard s (NAAQS) , Preven tiono f Significan t Deterioratio n(PSD) , Nonattainmen t (NA ) Are a Regulation s and Ne w Sourc e Performanc e Standard s (NSPS ) . Nationa l Ambien t Ai r Qualit y Standard s Nationa l Ambien t Ai r Qualit y Standard s (NAAQS ) ar e standard s establishe d b

y th e Clea nAi r Ac t t o protec t publi c health-an d welfare . Pollutant s fo r whic hNAAQ S ar e establishe d ar e calle d criteri a pollutant s an d include : sulfu r dioxid e (SO2) , nitrogen , oxide s (NOx) , carbo nmonoxid e (CO) , ozone , particulat e matte r (smalle r tha n1 0 micron s i ndiamete r o r PM-10 ) and lead . NAAQ S standard s ar e base d upo nscientifi c informatio nregardin g identifiabl e effect s onpubli c healt ho r welfare . Area s o f th e countr y whic har e incomplianc e wit hNAAQ S ar e calle d "attainment " area s an dar e subjec t t o th e Preventio no f Significan t Deterioratio n(PSD ) regulations ; area s no t i ncom plianc e wit hNAAQ S ar e terme d"nonattainment " an dar e subjec t t o a differen t se t o f rule s (th e Emissio nOffse t Interpretativ e Ruling ) unde r whic hne w source s may

no t b e permitte d t o caus e a ne t increas e i npollutio no r creat e a dela y i nmeetin g ai r qual it y standards . Designation s ar e mad e o na pollutant-specifi c basis ; thus , fo r example , a nare a ca nb e designate d attainmen t for carbo nmonoxid e bu t nonattainmen t fo r ozone . Preventio no f Significan t Deterioratio n Th e purpos e (PSD ) program , f o I960 , i s t o pres e progra m ther e ar e ambien t pollutan t pollutant s - SO2 , wer e se t t o "prev (e.g.baseline ) a i adde d t o baselin e o f the Preventio no f Significan t Deterioratio n r whic hfina l regulation s wer e issue di nAugus t rve ai r qualit y

inattainmen t areas . Unde r th e maximu m allowabl e increase s o r "increment's " in concentration s allowe dfo r thre e specifi c NOx , an

d particulat e matter . Thes e increment s en t significan t deterioration " inexistin g r quality . I neffect , th e PS D increment , whe n concentrations , represen t ne w ambien t ai r qual 

### 1 3IT

89-72. 4 89-72. 4 Tabl e IA . Significan t Emissio nRate s ity standard s fo r PS D areas . Wherea s NAAQ S limit s ar e applicabl e ove r th e entir e U.S . andrepresen t the greates t allowabl e degre e o f ai r contamination , th e PS D regulation s essentiall y establis h new ambien t standard s whic har e les s tha no r equa l t o NAAQ S an d whic har e determine do na nare a b y are a basis . Th e PS D permi t regulation s ar e triggere db y emission s o f certai npollutant s regulate dunde r th e Clea nAi r Ac t by a new sourc e o r b

y a majo r modificatio nt o anexistin g source . Modi fication s o f majo r source s ar e subjec t t o PS D permittin g i f emission s ar e mor e tha nsignificanc e level s whic har e liste d i n Tabl e IA . Majo r source s includ e facilitie s belongin g t o 2 8 cate gories , liste di nTabl e IIA , whic hhav e th e potentia l t o emi t 10 0 ton s pe r yea r o f an y pollutan t regulate dunde r th e Clea nAi r Act . Potentia l t o emi t mean s controlle demission s (afte r pollutio n contro l equipment ) whic har e base dupo nth e maximum desig ncapa cit y o f the source . Source s no t onthe lis t ar e considere d "major " i f the y

hav e emission s o f 25 0 ton s pe r yea r o r more . NonAttainmen t Are a A majo r new

stationar y

sourc e o r majo r modificatio nlocate d i na nonattainmen t are a mus t obtai na permi t unde r EPA' s Emissio n Offse t Interpretativ e Ruling . Thi s progra m require s a ne t ai r qualit y

improvemen t afte r th e sourc e begin s operation . Majo r ne w source s ar e subjec t t o revie w onl y i f the y

hav e th e potentia l t o emi t majo r amounts , generall y 10 0 ton s pe r yea r o r greate r o f the pollutan t fo r whic hth e are a i s designate dnonattainment . Modi fication s havin g th e potentia l t o increas e emission s b y greate r tha nsignificanc e level s ar e als o subjec t t o review . Unde r Stat e New

Sourc e Review

rule s fo r nonattainmen t areas , the sourc e mus t compl y wit hth e Lowes t Achievabl e Emissio nRat e (LAER ) an

d obtai nemissio nreduction s fro m othe r existin g source s tha t mor e tha noffse t th e increas e inemission s fro m th e new source . LAERi s base do nth e mos t stringen t emission s rat e containe dinth e implementatio npla no f an y stat e (unles s th e owne r candemonstrat e tha t suc ha limi t i s unachievable ) o r th e mos t stringen t emissio nlimitatio nachieve d i npractic e b y a sourc e o f the same category . Generally , cos t o r energ y impact s ar e no t considere di nLAE Ranalyses . He w Sourc e Performanc e Standard s Th e Ne w Sourc e Performanc e Standard s (NSPS ) ar e a se t o f nationa l emissio nstandard s fo r criteri a an d designate d pollut ant s fo r variou s categorie s o f new o r modifie d stationar y sources . Ther e ar e ove r 5 0 differen t type s o f stationar y source s - for whic hperformanc e standard s hav e bee nestablished .

1 5 Pollutan t Rat e (Ton/year )



### * * **. ** * *

a * 

### * * ** * *

* * * * 

### * * * * * * 

### * * 

### * *

a *



### * * * * * *

*a

a m Carbo nmonoxid e 100. 0

Nitroge noxide s 40. 0 Sulfu r dioxid e 25. 0 Tota l suspende d particulate s 25. 0 PM 1 0 (Particulat e Matte r < 1 0 microns ) 15. 0 Ozon e (volatil e organi c compounds ) 40. 0 Lea d 0. 6 Asbesto s 0.00 7 Beryllium

0.000 4 Mercur y

0. 1 Viny l chlorid e 1. 0 Fluoride s 3. 0 Sulfuri c aci d mis t 7. 0 Tota l reduce d sulfu r (includin g H2S ) 10. 0 Reduce d sulfu r (includin g H2S ) 10. 0 Hydroge nsulfid e 10. 0

Tabl e IIA . Majo r Stationar y Source s Fossil-fue l fire d stea m electri c plant s o f mor e tha n 25 0 millio nBTUpe r hou r hea t input . Coa l cleanin g plant s (wit htherma l dryers ) Kraf t pul pmills . Portlan dcemen t plants . Primar y

zin c smelters . Iro nand stee l mil l plants . Primar y

aluminu

m or e reductio nplants . Primar y

coppe r smelters . Municipa l incinerator s capabl e o f dischargin g mor e tha n25 0 ton s o f refus e pe r day . Hydrofluori c acid , sulfuri c aci dand nitri c aci d plants . Petroleum

refineries . Phosphat e roc k processin g plants . Cok e ove nbatteries . Sulfu r recover y

plants . Carbo nblac k plants . Lime plants . Furnac e process : Primary lea dsmelters . Fue l conversio n plants . Sinterin g plants . Secondar y

meta l productio nfacilities . Chemica l proces s plants . Fossil-fue l boiler s o f mor e tha n25 0 millio nBTU/h r hea t input . Petroleu

m storag e an

dtransfe r facilitie s wit hcapacit y exceedin g 300,00 0 barrels . Taconit e or e processin g facilities . Glas s fibe r processin g plants . Ch_rcoa l productio nfacilities . 1 6



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