Scott,

As a follow-up to our phone conversation this morni ng, I am providing a summary of the four instances where Colorado has allowed sources, under our existing NS R program, to use a time period that is different t han the two years (i.e., 24 months) immediately preceding t he proposed project to determine the source’s actua l emissions baseline for NSR permitting purposes:

Suncor Commerce City Refinery (West Plant) – Clean Fuels Project (to facilitate production of lower su lfur content fuels) Application submitted in Jan 2004 (two-year period immediately preceding would have been 2002 and 2003 ) Two-year period approved by Colorado: 2001 and 2003 Reason: During 2002, Suncor performed a major plan t turnaround/maintenance event at the refinery. Col orado determined that 2001 and 2003 were more representat ive of normal operation at the facility (netting ex ercise).

Lamar Utilities Board (Arkansas River Power Authori ty) – Lamar Repowering Project (converted from natu ral gas to coal-fired boiler) Application submitted in Dec 2004 (two-year period immediately preceding would have been approx. 2003 and 2004) Two-year period approved by Colorado: 2001 and 2002 Reason: LUB had historically operated a natural ga s fired boiler on site to generate electricity. Whe n natural gas prices increased substantially in 2003 and 2004, it was no longer economical for LUB to operate this b oiler.



### Summary of Instances Where Colorado Has Allowed a D ifferent Two-Year Actuals Baseline Hea, Roland C.

to: Scott Jackson 11/18/2011 12:13 PM Cc: "King, Kirsten L.", "Wojtach, Dena", Donald Law Hide Details From: "Hea, Roland C." <Roland.Hea@dphe.state.co.us >

To: Scott Jackson/R8/USEPA/US@EPA

Cc: "King, Kirsten L." <Kirsten.King@dphe.state.co. us>, "Wojtach, Dena" <Dena.Wojtach@dphe.state.co.us>, Donald Law/R8/USEP A/US@EPA

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...Colorado determined that 2001 and 2002 were more re presentative of normal operation at the facility (P SD

permit for some pollutants, netted out for NOx).

EVRAZ Rocky Mountain Steel – Pueblo Steel Mill (ste el production increase request) Application submitted in March 2011 (two-year perio d immediately preceding would have been 2009 and 20 10) Two-year period approved by Colorado: 2007 and 2008 Reason: Due to economic conditions, ERMS produced a lower amount of steel in 2009 than they had typic ally been producing since their new furnace had gone in to full operation, with demand picking back up in 2 010.
Colorado determined that 2007 and 2008 were more re presentative of normal operation at the facility (P SD permit).

OXY – Conn Creek Compressor Station in Garfield Cou nty (modifications to plant to remedy compliance is sues and facilitate production changes) Application originally submitted in April 2010 but revised several times during processing (two-year p eriod immediately preceding would have been approx. 2009 and 2010) Two-year period approved by Colorado: September 200 7 through August 2009 Reason: As a result of operational and compliance issues, OXY was required to shutdown two major piec es of process equipment at the plant, starting in Septemb er 2009. This equipment would normally run as part of the plant operations. Colorado determined that Septembe r 2007 through August 2009 was more representative of normal operation at the facility (netting exercise)

. Please let me know if you have any questions.

Thanks,
Roland

Roland C. Hea, P.E. Permitting Section Supervisor
Air Pollution Control Division Colorado Department of Public Health and Environmen t 4300 Cherry Creek Drive South Denver, Colorado 80246-1530

303-692-3252 303-782-0278 (Fax) roland.hea@state.co.us 

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