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# OAR Box 1778 Prepped by Ollie Stewart



### Document

Number: 

# 80 ) ll-C-2 2 Docket Number: 

# A-90-0 6

Printed 10/28/20089:50:55AM

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< r____« * / £ » r i UNITE D STATE S ENVIRONMENTA LPROTECTIO N AGENC Y

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" WASHINGTON , D.C . 2046 0 

## MA R26

## 199 1 OFFIC E O F AI R AN O RADIATIO N 

### Mr . Andre wAitke n Vic e P re s iden t r ^ - zfff ' \/AA '••:: \ Directo r o f Environmenta l Affair s Ne wEnglan dPowe r Servic e Compan yi\-<r . •• * 2 5 Researc hDriv e \\\U l B 

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### \ Westborough , Massachusett s 01582-009 9 Dea r Mr . Aitken : Thi s lette r i s i n respons e t o you r reques t fo r a determinatio no n th e applicabilit yo f Ne wSourc e Revie w(NSR ) regulation s an d Ne wSourc e Performanc e Standard s (NSPS ) t o th e additio no f natura l gas-burnin g capabilit ya t Ne wEnglan dPowe r Servic e Company' s Brayto nPoin t Station , Uni t No . 4 . A s yo u describe di n you r Januar y25 , 199 1 presentation , you r letter s o f Februar y1 an d Februar y19 , 1991 , an d i n subsequen t telephon e conversation s wit hScot t Throw e o f mystaff , th e projec t a t Uni t Ho. 4 i s a pollutio ncontro l projec t tha t i s bein g conducte da s par t o f a progra mt o compl ywit hstat e an d federa l aci drai nlaw s an d wil l no t expan dth e unit' s capacity , involv e extensiv e renovation s t o th e uni t o r exten dit s usefu l life . Yo u stat e tha t thi s projec t involve s th e installatio no f ne wgas/oi l low-NO xburner s i n Uni t No . 4 , replacin g th e existin g oil-onl y burners . Yo u hav e provide dEP Ainformatio nstatin g tha t this projec t wil l no t resul t i n a n increas e i n maximu mhourl yemission s o f an yo f th e pollutant s emitte d(S02 , NOx , PM , CO , VOC ) whe n firin g oil . Furthermore , yo u stat e tha t thi s projec t wil l resul t i na significan t decreas e i n th e maximu mhourl yemission s o f al l pollutant s emitte dwhe nfirin g gas . Th e NS Ran d NSP S provision s o f th e Clea nAi r Ac t appl yt o bot hne wsource s an d t o modification s o f existin g sources . I ngenera l unde r EP Aregulations , a physica l o r operationa l chang e whic hincrease s emission s ove r baselin e level s i s a modificatio n tha t trigger s thes e ne wsourc e requirements . Unde r NSPS , a n emission s increas e i s define da s a n increas e i n maximu mhourl y emission s [se e 4 0 CF R60.14] . Unde r NSR , a n emission s increas e i s define da s a n increas e i n annua l actua l emission s t o th e atmospher e [se e e.g. , 4 0 CF R51.165(a ) (1 ) (v ) (A ) an d (vi)(A) , an d 4 0 CF R52.21(b ) (2 ) (i ) an d (3 ) (i)] . EP Aha s observe dtha t thes e

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- definition s can b e interprete d i n suc ha manne r a s t o subjec t t o NSR , NSPS , o r both , certai n environmentall ybeneficia l activitie s whic hneithe r Congres s no r EP Aintende d t o b e covere d b yne wsourc e requirements . EPA' s curren t interpretatio n o f it s NS Rand NSP S regulation s i s tha t environmentall ybeneficia l activitie s suc ha s pollutio n contro l project s involving th e additio no f pollutio ncontro l equipmen t or , a s i n th e cas e o f Brayto nPoin t th e us e o f a les s pollutin g fuel , ar e no t th e typ e o f physica l o r operationa l change s intende d t o b e covere d bythe-EPA' s regulations . Therefore , pollutio n contro l project s ar e no t modification s fo r th e purpose s o f NSP S o r majo r modification s fo r th e purpose s o f NSR . EP Aha s determine d tha t th e installatio no f ne wgas/oi l low

NO xburner s i n uni t No . 4 a t Brayto n Poin t i s anenvironmentall y beneficia l pollutio n contro l projec t tha t shoul d no t b e considere d a physica l o r operationa l chang e withi nth e meanin g o f th e NS Ro r NSP S regulations , and i s no t subjec t t o th e requirement s o f NS Ro r NSPS . EP Ai s i n th e proces s o f drafting a n interpretativ e ruling t o provid e furthe r guidanc e o n defining wha t activitie s d o no t constitut e a modificatio n tha t ma ytrigge r applicatio no f ne w sourc e requirements . I n particular , i f a sourc e onl yadd s o r enhance s system s o r device s whos e primar yfunctio ni s th e reductio n o f ai r pollutio n an d ar e determine d t o b e environmentall ybeneficial , the n thos e activitie s wil l no t constitut e a physica l o r operationa l chang e triggerin g ne wsourc e requirements . Pleas e b e awar e tha t this - lette r doe s no t exemp t Ne wEngland Powe r Servic e Compan yfroman

yapplicabl e stat e regulations . I f yo u hav e an

yquestions , pleas e contac t John Rasni c o f m y staf f a t (703 ) 308-867 2 o r EPA' s Regiona l offic e i nBoston . You r contac t ther e wil l b e Mr . Loui s F . Gitt o wh o ca nb e reache d a t (617 ) 835-3800 . 

# T' WilliamG . Rosenber g Assistan t Administrato r Offic e o f Ai r and Radiatio n

cc : R . Brenner , OPAR(ANR-443 ) L . Gitto , Regio n 1 B . Tyndall , OG C (LE-132A ) D . Solomon , AQMD (MD-15 ) S . Throwe , SSC D (EN-341W )