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# OAR Box 1787 Prepped by Ollie Stewart



### Document

Number: 

# 49 ) ll-C- 7 Docket Number: 

# A-90-3 7

Printed 11/4/200810:22:19AM

Sheet 49of 147P. 2



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## 1294
. UNITE D STATE S ENVIRONMENTA LPROTECTIO N AGENCY REGIO N 5 AI R AN D RADIATIO N DIVISIO N 7 7 WES TJACKSO N BOULEVAR D CHICAGO , I L60604-359 0 

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# O S 199 3 REPL YT O TH E ATTENTIO N OF : (AT-18J )



## ji b Denni s Drake , Actin g Chie f Ai r Qualit yDivisio n Michiga n Departmen t o f Natura l Resource s P.O . Bo x3002 8 Lansing , Michiga n4890 9 Dea r Mr . Drake : Thi s lette r concern s a proposa l byGenera l Motor s (GM ) t o bur n natura l ga s i nexistin g industria l boiler s a t a nestimate d 1 6 site s i nth e Stat e o f Michigan , and 1 2 othe r site s i nRegio n5 . Th e unit s a t issu e currentl ybur ncoa l o r fue l oil . Durin g a February23 , 1993 , telephon e conferenc e betwee nGM , th e Unite d State s Environmenta l Protectio n Agenc y(USEPA) , and th e Michiga nDepa:rtmen t o f Nattira l Resource s t o discus s thes e alternat e fue l projects , GMwa s aske d t o provid e a demonstratio ntha t a chang e i nfuel s woul d no t affec t futur e aut o productio n rate s a t thes e facilities . Th e dat a provide d byGMi n a Marc h9 , 1993 , lette r indicat e tha t th e utilizatio nrat e o f th e boiler s woul d no t b e influence d bya switc h t o thi s mor e economica l fue l becaus e (1 ) th e tota l steamcos t a t a give nplan t i s insignifican t whe ncompare d t o th e tota l operatin g cos t a t tha t plant , and (2 ) th e steamproductio ni s primaril y determine d b

yclimat e conditions , no t aut o productio nrates . Th e Ne wSourc e Revie w(NSR ) regulator yprovision s requir e tha t a propose d pnysica l chang e resul t i n a nincreas e i nactua l emission s i n orde r fo r th e chang e t o b e considere d a modificatio n and therefor e subjec t t o NSR . See , e.g. , 4 0 Cod e o f Federa l Regulation s 52.21(2)(i) . I nthi s case , th e propose d switc ht o natura l ga s a t variou s GMfacilitie s wil l resul t i n substantia l reduction s i n th e emission s factor s o f particulat e matter , sulfu r dioxide , and , i nmos t cases , oxide s o f nitrogen , a s wel l a s ai r toxics . Th e us e o f natura l ga s wil l als o resul t i na substantia l cos t saving s fo r th e source . I ngeneral , wher e a sourc e make s a chang e tha t reduce s th e cost s o f production , suc hchange s usuall yaffec t th e utilizatio no f th e facility . I nthi s case , GMha s clearl ydemonstrate d tha t th e utilizatio nrat e o f th e boiler s wil l no t b e affecte d b yth e propose d fue l switc ht o natura l gas . Consequentl ysinc e th e emission s factor s fo r al l relevan t pollutant s wil l decreas e and neithe r th e rat e o f productio n no r hour s o f operation s o f th e facilitie s wil l increas e a s a resul t o f th e change , USEP Aha s determine d tha t th e propose d-2

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project s wil l no t resul t i n a nincreas e i nemissions . Therefore , base d o nth e specifi c circumstance s and dat a presented , i t i s USEPA' s vie wtha t GM' s propose d natura l ga s conversio nproject s shoul d no t b e considere d a majo r modificatio nunde r th e Federa l Ne wSourc e Revie w regulations . I f yo u hav e anyquestion s wit hregar d t o thi s letter , pleas e contac t me . Sincerel yyours ,

— y Davi d Kee , Directo r Ai r and Radiatio n Divisio nP. 4

standar d bcc's : officia l fil e copyw/attachment(s )

originator' s fil e copyw/attachment(s ) originatin g organizatio n readin g fil e w/attachment(s ) othe r bcc's : D . Kee , AR D

K . Berry , OAQP S B . Tyndall , OG C

: D . Crumpler , OAQP S S . Rothblatt , RD B G . Gulezian , ATR B G . Czerniak , AE B R . Va n Mersbergen , RD B ARD:ATRB:GMPES:CAMPBELL:cc:4/1/9 3 DISKETTE/FILE:F:\USER\CCAMPBEL\MDNR.GM



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