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EPA Region 6 feedback on AECC Bailey and McClellan- SO2 and PM BART 

 In our August 2012 conference call, AECC explained that in the October 2006 SO2 BART 

analysis for the Bailey and McClellan plants, the permit limits (fuel oil with 2.3% and 2.8% 

sulfur) were used as the base case for the sulfur content of fuel oil burned. In the revised draft 

BART analysis, AECC used historical averages of actual sulfur content of fuel oil burned as the 

new base case (fuel oil with 1.81% and 1.38% sulfur). AECC explained that the new base case is 

very close to (and more representative of) the actual SO2 emissions during the 2001-2003 

baseline period than are the permit limits. Region 6 asked AECC to include in the BART 

analysis this justification for using the new base case and to provide documentation of the 

historical actual sulfur content of fuel oil burned at the two units. 

 On the conference call, Region 6 pointed out that AECC’s revised cost analysis for switching to 

a different fuel type is inconsistent with AECC’s October 2006 analysis and with the 

documented cost-differential of switching from greater than 1% to less than 1% fuel oil at other 

comparable units. AECC explained that the revised cost analysis was based on a very limited 

number of fuel oil purchases made by the facility and that the inconsistency between the revised 

analysis and the October 2006 analysis is primarily due to market fluctuations. It appears that 

AECC based the revised cost analysis on the actual price paid for a very limited number of fuel 

oil purchases made in past years, which may have resulted in outdated fuel oil cost numbers and 

an overestimation of the cost of fuel oil when compared to the cost in today’s market. Region 6 

asked AECC to obtain vendor quotes for the current cost of all evaluated fuels, including the 

currently used fuel, and include this in the BART analysis, and to update the cost analysis using 

the cost numbers obtained from the vendor’s quote. 

 EPA expressed concern about the following statement made on page 5-12 of AECC’s revised 

draft BART analysis for SO2: “When the BART limits become effective, Bailey and McClellan 

would burn the existing supply of No. 6 fuel oil as the normal course of business dictates. Future 

fuel purchases will be fuels of 0.5% sulfur content or less.” On the conference call, AECC 

clarified that its current fuel oil supply is for 100 days or less and that the Bailey and McClellan 

units would be able to comply with BART as expeditiously as practicable, but no later than 5 

years from approval of BART. We recommend that to avoid confusion, AECC either remove the 

above quoted statement from the BART report or revise the language to make the statement 

consistent with the compliance requirements under 40 CFR section 51.308(e)(1)(iv) of the 

regional haze regulations. We remind ADEQ that Chapter 15 of Regulation No. 19 of the 

Arkansas Pollution Control and Ecology Commission (APCEC), also known as Arkansas’s 

regional haze rule, must also be consistent with the compliance requirements under 40 CFR 

section 51.308(e)(1)(iv) and that under 40 CFR section 51.230 the state must have the legal 

authority to enforce all regulations submitted into the SIP. 

 Concerning the bullet point above, we remind ADEQ that in our March 12, 2012, final action on 

the Arkansas RH SIP (see 77 FR 14655) we partially approved and partially disapproved 

APCEC Reg. 19.1504(B), which provides that “Each source subject-to-BART shall install and 

operate BART as expeditiously as practicable, but in no event later than 6 years after the 

effective date of this regulation or 5 years after EPA approval of the Arkansas Regional Haze 
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State Implementation Plan, whichever comes first.” Our final partial disapproval of Reg. 

19.1504(B) applied to that portion of the regulation that requires compliance with BART 

requirements no later than six years after the effective date of the State’s regulation (if such date 

takes place before five years from EPA approval of the Arkansas RH SIP). As explained in our 

final action, the partial disapproval was because in March 26, 2010, the APCEC issued Minute 

Order No. 10-08, granting all Arkansas subject-to-BART sources a variance from the compliance 

deadline imposed by APCEC Reg. 19.1504(B). Although we believe the compliance timeframe 

in Reg. 19.1504(B) is consistent with the requirements under 40 CFR 51.308(e)(iv), because of 

the variance granted to all Arkansas subject to BART sources (which has never been submitted 

into the SIP), the State of Arkansas does not have the legal authority to enforce compliance 

within the timeframe required by Reg. 19.1504(B). Specifically, Arkansas currently does not 

have the authority to enforce compliance with BART within six years after the effective date of 

its regulation. 40 CFR section 51.230 requires that a state must show it has the legal authority to 

enforce a rule that is submitted as part of the SIP. Our recommendation to ADEQ is that Reg. 

19.1504(B) be revised such that it is consistent with the compliance requirements under 40 CFR 

section 51.308(e)(1)(iv) and such that the State has the legal authority to enforce the regulation 

submitted into the SIP. Alternatively, we recommend that Minute Order No. 10-08 granting 

Arkansas BART sources a variance from the compliance deadline imposed by Reg. 19.1504(B) 

be submitted as part of the SIP. 

 On the conference call, AECC agreed to follow up with Region 6 on several concerns we 

expressed regarding the emission rates used in the modeling analysis. Section 1 of the BART 

analysis states that the pre-control visibility impairment of each unit is based on modeling of 

emission rates that were derived from stack testing, CEMS, and AP-42 emission factors. Section 

4-1 explains that the SO2 and NOx emission rates modeled are actual maximum 24-hour 

emission rates based on CEMS data and that the PM10 emission rates modeled are based on 

maximum burner capacities using AP-42 emission factors. However, it is unclear how stack 

testing was used to derive any of the emission rates modeled. The SO2 emission rates and the 

revised NOx baseline emission rates appear to be consistent with the maximum daily emission 

rates during the baseline period of 2001-2003. The revised PM emission rates are significantly 

lower than those used in the original BART analysis (summarized in the table below) and appear 

to be inconsistent with AP-42 emission factors and the maximum burner capacities. The source 

should explain the revised PM emission rates and provide emission estimation calculations. 

AECC BART engineering analysis, October 20, 2006 

Unit SO2 NOx PM(modeled values for 

PMc and PMf) 

 g/s lb/hr g/s lb/hr g/s lb/hr 

Bailey Unit 

1 299.34 2375.75 36.93 293.1 21.73 172.46 

McClellan 

Unit 1 346.19 2747.56 47.12 373.97 28.76 228.26 
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Revised AECC BART baseline modeling 

Unit SO2 NOx Total PM10 (speciated into 

PMc, PMf, EC, and SOA) 

 g/s lb/hr g/s lb/hr g/s lb/hr 

Bailey Unit 

1 299.34 2375.8 51.51 408.8 6.22 49.4 

McClellan 

Unit 1 346.19 2747.5 73.05 579.8 6.07 48.2 

 Visibility modeling of fuel switching scenarios should include the decrease in PM emissions 

anticipated from switching to lower sulfur fuels. While visibility impacts from PM are relatively 

small, visibility benefits from decreases in PM emissions as a result of fuel switching should be 

accounted for. Region 6 asked AECC to include in the BART analysis a brief discussion of the 

impact of reductions of PM emissions on visibility to address this. 

 In calculating the SO2 emission rates to model to reflect fuel switching, the maximum emission 

rate from the baseline period should be used rather than the average. Additionally, the sulfur 

content used to scale this emission rate should be representative of the sulfur content of the fuel 

burned during the same baseline period and reflected in the baseline emission rate. There also 

appears to be an error in the ratio used in the calculation as shown on page 5-8. If AECC 

chooses not to re-model using the maximum SO2 emission rates at this time, then a justification 

should be provided explaining what impact if any using the maximum emission rates would have 

on the modeling results and the ultimate BART determination 

 The source should include a plot showing the meteorological modeling domain, computational 

modeling domain, location of sources, and Class I area receptor locations used in the visibility 

analysis.