### Date: December 16, 2011 Subject: National Emission Standards for Haza rdous Air Pollutants (NESHAP) Maximum Achievable Control Technology (MACT) Fl oor Analysis for Coal- and Oil-fired Electric Utility Steam Generating Units for Final Rule

From: Jeffrey Cole (RTI International)

To: Bill Maxwell OAQPS/SPPD/ESG (D243-01) U.S. Environmental Protection Agency Research Triangle Park, NC 27711

Introduction Section 112 of the Clean Air Act (CAA) require s that the U.S. Environmental Protection Agency (EPA) establish National Emission Standards for Hazardous Air Pollutants ( NESHAP) for the control of the hazardous air pollutants (HAP) emitted from both new and existing sources in a source category. These standards must re flect the maximum degree of reduction in the HAP emissions that is achievable. The minimum leve l of control is referred to as the “Maximum Achievable Control Technology (MACT) floor.” The method for determining the MACT floor as the minimum control level allowed for establishing standards for a NESHAP is defined for both new and existing sources by CAA section 11 2(d)(3). For new sources, the MACT floor cannot be less stringent than the emission c ontrol that is achieve d in practice by the best-controlled similar source. For existing sour ces, the MACT floor cannot be less stringent than the average emission limitation achieved by the best-performing 12 percent of existing sources for source categories wi th 30 or more sources, or the best-performing 5 sources for source categories with fewer than 30 sources. The purpose of this memorandum is to present the methodology and the results of the MACT floor analysis for the NESHAP source ca tegory “Coal- and Oil-fired Electric Utility Steam Generating Units” (referred to in this memorandum as “EGUs”). This MACT floor analysis uses data collected in a nationwide su rvey of EGU owners and operators conducted by the EPA in 2010 under the Information Collection Request Fo r National Emission Standards For Hazardous Air Pollutants (NESHAP) for Coal- A nd Oil-Fired Electric Utility Steam Generating Units (OMB Control No. 2060

‐ 0631). Individual EGU operating a nd air emissions data reported by respondents to the Information Collection Re quest (ICR) were compiled into a Microsoft Access ® 

### data base that serves as the data set used for this MACT floor analysis (referred to in this memorandum as the “ICR data set”).

MACT Floor Analysis Hazardous Air Pollutants The specific chemicals, compounds, or groups of compounds designated to be HAP are listed in CAA section 112(b). Included on the li st are metals, organic compounds, and inorganic chemicals. From this HAP list, the following HAP, among others, were identified to be emitted from EGUs and were included in the MACT floor analysis: the metals antimony (Sb), arsenic

### 2 (As), beryllium (Be), cadmium (C d), chromium (Cr), cobalt (Co) , lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni), and selenium (S e); organic HAP, and the acid gases hydrogen chloride (HCl) and hydrogen fluoride (HF). In a ddition to these individual pollutants, MACT floor levels were analyzed usi ng filterable particulat e matter (fPM) emissions as a surrogate for HAP metals other than Hg (non-Hg metallic HAP) for coal-fired units and as a surrogate for total HAP metals for oil-fired units. In addition, MACT floor levels were analyzed using HCl as a surrogate for all acid gas HAP, and sulfur dioxide (SO 2 

### ) emissions as an alternative equivalent surrogate pollutant for acid gas HAP for units eq uipped with flue gas desulfurization systems for coal-fired units and solid oil-fired units.

MACT Floor Analysis Subcategories Under CAA section 112(d)(1), the EPA ha s the discretion to “...distinguish among classes, types, and sizes of sour ces within a category or subcate gory in establishing...” standards. When separate subcategories are established, a MACT floor is determined separately for each subcategory. To determine whether the EGU so urce category warrants subcategorization for the MACT floor analysis, the EPA reviewed EGU design, operating information, and air emissions data compiled in the ICR data set and othe r information collected by the Agency for development of the NESHAP for this source ca tegory. Based on this review, the EPA concluded that there are significant design and operational differences in EGUs that affect the levels of emissions of certain HAP to justify subcategor izing EGUs for the purpose of establishing MACT floors.
The data available to the EPA show that th e levels of HAP emissions for EGUs burning solid coal are the same for all of the HAP constituents except H g. To account for the differences in Hg emissions from these units, the EPA iden tified two subcategories for EGUs burning solid coal. The HAP emissions from integrated gasifica tion combined cycle (IGCC) EGUs are distinct from EGUs burning solid coal because IGCC burn a synthetic gas derived from coal or from a blend of coal and solid oil-derived solid fuel (i .e., petroleum coke). Consequently, a separate subcategory is defined for IGCC units. The data also show differences in all HAP emissions from oil-fired EGUs compared to coal-fired EGUs. Within the grouping of oil-fired EGUs, we have established four (4) subcategories based on distinct differences in the HAP emissions levels from the subcategories. For liquid oil-fired E GUs, we are establishing a subcategory for units located inside the continental United States , a subcategory for units located outside the continental United States, and a subcategory for oil-fired EGUs located inside the continental United States that have an annual oil-fired capacity factor of less than 8 percent. Furthermore, we are also establishing a subcategory for solid oil-fi red EGUs because there are distinct differences in the HAP emissions levels from oil-fired EGUs units depending on whether liquid fuel oil is burned or a petroleum-deri ved solid fuel is burned.

### 3 For the MACT floor analysis, the followi ng seven EU subcategories were defined: Subcategory 1

. New and existing EGUs designed to bur n a coal having a calorific value (moist, mineral matter-free basis) of greater than or equal to 19,305 kJ/kg (8,300 Btu/lb) that are not coal-fired EGUs in the “unit designed for low rank, virg in coal” subcategory. 1


### Subcategory 2

. New and existing EGUs designed to burn and burning nonagglomerating virgin coal having a calorifi c value (moist, mineral matter-f ree basis) of less than 19,305 kJ/kg (8,300 Btu/lb) that are c onstructed and operated at or near the mine that produces such coal. Subcategory 3

. New and existing IGCC EGUs. Subcategory 4

. New and existing EGUs located inside the continental United States that burn liquid oil and have an annual oil-fired cap acity factor of greater than or equal to 8 percent. Subcategory 5

. New and existing EGUs located inside the continental United States that burn liquid oil and are classified as limite d use by having an annual oil-fired capacity factor of less than 8 percent. Subcategory 6

. New and existing EGUs located outside the continental United States that burn liquid oil. Subcategory 7

. New and existing EGUs that burn solid oil-derived fuel.

Calculating Emission Values used in the MACT Floor Analysis
The EPA received emissions data from indus try respondents under the Electric Utility (EU) MACT ICR in a number of different units of measure and converted these units of measure to a common pound per million British thermal units (lb/MMBtu) and pounds per megawatt-hour (lb/MWh) basis shown in the statistical analysis spreadsheets. The emissions data could have been submitted under Part II of the ICR (histo rical stack testing conducted from 1/1/2005 to 12/31/2009) or from Part III of the ICR (tes ting done in 2010 or 2011 specifically for the 2010 EGU MACT ICR). Although the Part III data was s ubmitted in the units of measure specified by EPA, the Part II data came in a variety of un its of measure. The procedures used for making these unit conversions and the EP A’s procedure for converting a uni t’s stack emission data from a lb/MMBtu basis to a lb/MWh basis are presented in Attachment A. To en sure data quality, the EPA performed three levels of outlier analyses on the submitted data averages before they were considered for the floors. The first level was a visu al plotting of the data via a scatter plot to identify obvious outliers that warranted removal from the data set pendi ng further investigation. Using the scatter plot method of outlier identification, 14 data av erages were removed from floor consideration. These averages, their pollutant, and unit name are also listed in a table in the attachments. Once these data we re removed, the remaining data were then sorted by emission average (low to high) and the MACT floor se ts of averages were chosen following the methodology discussed in the following sections. Subs equent outlier analyses were conducted as part of the statistical anal ysis as discussed on page 12.

1 Subcategories 1 and 2 were differentiated for mercury emissions only. The remaining standards finalized in this action are the same for the two subcategories.

### 4 MACT Floor Analysis Methodology The first step in the MACT floor analysis for each subcategory and HAP (or surrogate) was to rank all of the EGUs in the subcategory (for which there were emissions data in the ICR data set) for the pollutant type by emission level (lowest to highest). From this ranking, a MACT floor pool of sources was identified for determ ining the minimum control level allowed for the MACT floor, consistent with th e criteria defined for new and existing sources by CAA section 112(d)(3). For the new-source MACT floors, the be st-controlled similar s ource was identified for which there were individual sour ce test run data in the ICR da ta set. For the existing-source MACT floors, selection of the MA CT floor pool size (i.e., number of EGUs to be included in the determination of the average emission limitation value) was determined on an individual subcategory basis as described below. Subcategory 1

. The existing-source MACT floors for fPM, HCl, SO 2 

### , total non-Hg HAP metals, and individual non-Hg HAP metals em issions were based on the top 12 percent of the total number of EGUs in the nationw ide subcategory coal- and oil-fired EU population (12% of 1,082 sources or 130 EGUs ). The existing-source MACT floor for Hg emissions was based on the top 12 percen t of the total number of the subcategory EGUs with Hg emissions in the ICR data se t (12% of 388 sources or 47 EGUs). In the ICR, EPA required the units selected for non-me rcury metal HAP testing to also test for mercury because the test methods are similar for mercury and non-mercury HAP. Subcategory 2

. This subcategory includes greater th an 30 (i.e., 36) sources. The EPA differentiated coal-fired units solely for Hg emissions and the existing-source MACT floors for fPM, HCl, SO 2 

### , total non-Hg HAP metals, and individual non-Hg HAP metals emissions were based on the same MACT floor data pool used for Subcategory 1 . The existing-source MACT floor for Hg emissions for this subcategory was based on the top 2 EGUs of the subcategory for which the EPA had emissions data (12% of 11 sources or 2 EGUs). Subcategory 3

. This subcategory includes 2 source s. The existing-source MACT floors for all HAP and surrogate pollutant emissi ons were based on the data for both IGCC EGUs in the subcategory. Subcategory 4

. This subcategory includes 40 sources. The existing-source MACT floors for all HAP and HAP surrogates emissions were based on the top 12 percent of the total number of the subcategory EGUs in each specific pollutant’s ICR data set. Subcategory 5

. This subcategory includes 78 sources . The existing- and new-source MACT floors will be achieved through work practice standards with no numerical emission limits established. Subcategory 6

. This subcategory includes 31 sources. The existing-source MACT floors for all HAP and HAP surrogates emissions were based on the top 12 percent of the total number of the subcategory EGUs in each specific pollutant’s ICR data set. Subcategory 7

. This subcategory includes 11 sources and the ICR data set includes data from 9 of those sources. The existing -source MACT floors for all HAP and HAP surrogates were based on the top five EGUs of the subcategory EGUs in the ICR data set. The next step in the MACT floor analysis wa s to incorporate data variability into the calculations of the applicable MACT floor limits for the subcategories using a 99 percent upper

### 5 prediction limit (UPL) approach. Specifically, the MACT floor limit is an UPL calculated with the Student’s t-test using the “T INV” function in Microsoft Excel ® 

### software. The Student’s t-test has also been used in other EPA rulemakings (e.g., NESHAP for Portland Cement, NSPS for Hospital/Medical/Infectious Waste Incinerators [HMIWI], NESHAP for Industrial, Commercial, and Institutional Boilers and Process Heaters) in accounting for variability and reflects the level of confidence. The level of conf idence represents the level of pr otection afforded to facilities whose emissions are in line with the best perfor mers, and consequently, the level of confidence is not arbitrary. For example, a 99 percent leve l of confidence means th at a facility whose emissions are in line with the best performers has one chance in 100 of exceeding the floor limit. A prediction interval for a single future observati on (or an average of seve ral test observations) is an interval that will, with a specified degree of confidence, contain the next (or the average of some other pre-specified number) of randoml y selected observation(s) from a population. In other words, the UPL estimates what the upper bound of future values will be, based upon present or past background samples taken. The UP L consequently represents the value at which we can expect the mean of future observations for the HAP or HAP surrogate emissions to fall within a specified level of confidence, base d upon the measurements from an independent sample from the same population. The UPL appro ach encompasses all the data point-to-data point variability. The predictions derive from the da ta set to which it is applied, and, thus, can be applied to any type of data. The form of the UPL equation differs somewh at depending upon the nature of the data set to which it is applied. To this end, the data sets were evaluated for each HAP and HAP surrogate to ascertain whether th e data were normally distributed, or distributed in some other manner (i.e., log normally). For data sets where the number of available EGUs was 15 or more, use of the UPL was based on assuming a normal distribution based on the Central Limit Theorem (Durrett, 1996). The Central Limit Theorem states that regardless of the shape of the original distribution, if the distribu tion has a finite mean ( μ ) and variance ( σ 2), the sampling distribution of the mean approaches a normal distribution with a mean of ( μ ) and a variance of σ 2/N as N, the sample size, increases (Durrett, 1996). When the sample size is smaller than 15 a nd the distribution of the data is unknown, the Central Limit Theorem cannot be used to support the normality assumption. Statistical test of the kurtosis, skewness, and goodness of fit test are th en used to evaluate the normality assumption. The skewness statistic (S) characterizes the degree of as ymmetry of a given data distribution. Normally distributed data have an S value of 0. An S value that is greater (less) than 0 indicates that the data are asymmetrically distributed with a right (left) tail extending towards positive (negative) values. Further, the standard error of the skewness statistic (SES) can be approximated by SES = SQRT(6/N), where N is the sample size. According to the small sample skewness hypothesis test, if the S value is greate r than two times the SES, the data distribution can be considered non-normal. The kurtosis statistic (K) characterizes th e degree of peakedness or flatness of a given data distribution in comparison to a normal distribution. Normally distributed data have a K value of 3. A K value that is greater (less) than 3 indicates a relatively peaked (flat) distri bution. Further, the standard error of the kurtosis statistic (SEK) can be approximated by SEK = SQRT(24/N), where N is the sample size. According to the small sample kurtosis hypothesis test, if the K value is greater than two times the SEK value, the data distribution is typically c onsidered to be non-normal.

### 6 For each data set to which the UPL was applie d (i.e., the separate data sets for each HAP and HAP surrogate type applicable to the subcategory), the S and K statistics were calculated using both the reported test values and the log-tr ansformed reported test values. If the S and K values statistics of the reported data set were both less than twice the SES and SEK, respectively, the dataset was classified as norma lly distributed. If neither of th e S and K values, or only one of these statistical values were less than twice the SES or SEK, respectively, then the skewness and kurtosis hypothesis tests were c onducted for the natural log-tran sformed data. If the S and K values of the log-transformed reported data se t were both less than twice the SES and SEK, respectively, the log-transformed dataset was classi fied as normally distributed. In this case, the MACT floor was calculated using an UPL equation developed for log-normal data (Bhaumik and Gibbons, 2004). If both the reported values and the natural-log transformed reported values had S and K values that were greater than twi ce the SES or SEK, re spectively, the normally distributed dataset was selected as the basis of the floor to be conservative. If the results of the skewness and kurtosis hypot hesis tests were mixed for the re ported values and the natural logtransformed reported values, the normal distribut ion was chosen to be conservative. This approach is more accurate and obtained more representative results than a more simplistic normal distribution assumption. Specifically, in the case of normal distribu ted data, the MACT floor limit is an UPL calculated as:

UPL = 2 ,.99 

### 1 1
df 

### xt s n m        



### Where:



= mean of the top performing sources calculated as

1 1 

### 1 i n N

ij i j 

### x x n

  

###  

#  

n = Number of test runs =

m = Number of future test runs in the compliance average

N = Number of sources

s 2 

### = pooled varian ce calculated as

t df, 99 

### = 99 th 

### – quantile of t-distribution with df degrees of freedom

df

= degrees of fr eedom calculated as 1 N

i i 

# n

 

# 

  2 2

1 

# 1
1 n

i i 

# s x X
n

 

#  

 

# 

1 

### 1 N

i i 

### df n

 

###  

     



# 

### 7 This calculation was performed using the following Excel ® 

### functions:
Normal distribution: 99 th 

### Confidence UPL = AVERAGE(Test Runs in Top 12%) + [STDEV(Test Runs in Top 12%) x TINV (2 x probability, n-1 degrees of freedom)*SQRT((1/n)+(1/m))], for a one-tailed t-value, pr obability of 0.01, and sample size of n.

The 99 th 

### confidence UPL was selected as a reas onable upper limit because only 1 percent of future tests of the MACT pool of lowest emitting EGUs will exceed the limit if they are performing as well as the emission test data indi cate (i.e., these EGUs will be below or achieve the limit 99 percent of the time in the future). If variability was not accounted for in this manner and a limit was set based solely on the average pe rformance, then these EGUs could exceed the limit half the time or more. For some data sets, a single floor average pe r source or unit was available; analysis based solely in these single per unit observations will not reflect any possible within-source variability. In cases where additional available emissions data from past years were available, it was decided to incorporate these data in the estimation of the variance term, s 2 

### , allowing for consideration of within- and between-source variab ility. The most recent data (e .g., single floor average) were used to calculate the average in the UPL equation. The UPL equation for this case is calculated

as:

UPL = 2 ,.99 

### 1 1
df 

### xt s N m        



### Where:
m = Number of future test runs in the compliance average

N

= Number of units involved in calculati ng the average (a single measurement (e.g., floor average) per unit)

n i 

### = Number of data points (e.g., stack averag es) collected in the past for the i-th source

1 N

i i 

### nN n

 

###   

# 

i 

### x 

### = Current information (e.g., single fl oor average) for the i-th source

i 

### y 

### = Past information (e.g., stack average) for the i-th source

x 

### = mean of the top perf orming sources calculated as

1 

### 1 N

i i 

### x x N

 

###  

# 

x



### = grand mean (mean of the current and past information from the top performing sources

### 8 1 11 

### 1 i n N N

i i i ij 

### x x y n

 



###  
     



#  

s 2 

### = variance calculated as 

#   

#   2 2 2

1 11 

### 1
1 i n N N

i ij i ij 

### s xx y x n

  

###  
    

   

#  

t df, 99 

### = 99 th 

### quantile t-distribution with df degrees of freedom

df

= Degrees of freedom = n -1

The calculation of this UPL was performed using the following Excel ® 

### function:
Normal distribution: 99% UPL = AVERAGE (Test Runs in Top 12%) + [STDEV(Test Runs in Top 12%, stack averages) x TINV(2 x probability, (n-1) degrees of freedom)*SQRT((1/N)+(1/ 3))], for a one-tailed t-value (with 2 x probability), probability of 0.01, and sample size of n. The UPL, to test compliance based on a 3 -run average and assuming log-normal data, is calculated by the following equation (Bhaumik and Gibbons, 2004):

2

ˆ 22 2 2 2 4

ˆ ˆˆ ˆ ˆˆ 2 22 .99 

### ˆ ˆ ( 1) 2( 1) z UPL e me e m e
m nn      

###  

   

###  
     

  



### Where: 

#  
1 

### log

ˆ n i i 

### y

n   

###  

#  the average of the log transformed data from the top performing sources



#   

#   2

2 1 

### ˆ log

ˆ 1 n i i 

### y

n    

### 



 

#  the variance estimate of the log transformed data from the top

performing sources

z .99 

### is the 99 th 

### -percentile of the log-normal distributi on estimated using the trapezoidal rule approach from the following equation: 

#     

#  

.99 2 4 2 1 3

0 

### 336 1 3 ( ) .99 6 24 z z z 

### z z zz z               

# 

### 9 The calculation of this log-normal based UP L was performed using the following Excel ® 

### function:
Normal distribution: 99% UPL = EXP(AVERAGE(LN(Test Runs in Top 12%)) + VAR(LN(Test Runs in Top 12%))/2) + (99 TH 

### -PERCENTILE LOGNORMA L DISTRIBUTION/m)* SQRT(m*EXP(2* AVERAGE(LN(Test Runs in Top 12%))+ VAR(LN(Test Runs in Top 12%)))*(EXP(VAR(LN(Test Runs in Top 12%)))-1)+ m^2* EXP(2* AVERAGE(LN(Test Runs in T op 12%))+ VAR(LN(Test Runs in Top 12%)))*( VAR(LN(Test Runs in Top 12%))/n+ VAR(LN(Test Runs in Top 12%))^2/(2*(n1)))

The 99 th 

### percentile of the log-normal distribu tion was calculated following Bhaumik and Gibbons (2004).

Adjustment for Below Detect ion Level Emissions Data To account for the effect of measurement impr ecision associated with the data in the ICR databases (that include method de tection level data), a protocol specified by the EPA was used. The procedure for determining a representative de tection level (RDL) begi ns with identifying all of the available reported polluta nt-specific method detection levels for the best performing units regardless of any subcategory (e.g., existing or new, fuel type, etc.). From that combined pool of data, we calculate the arithmetic mean value. By limiting the data set to those tests used to establish the floor or emissions li mit (i.e., best performers), the EPA believes that the result is representative also of the be st performing testing companies and laboratories. The EPA also believes that the outcome should minimize the eff ect of a test(s) with an inordinately high method detection level (e.g., the sample volume wa s too small, the laboratory technique was insufficiently sensitive, or the procedure for dete rmining the detection level was other than that specified). The EPA then calls the resulting mean of the method detection levels the RDL, and the Agency considers it characteristic of accep ted source emissions measurement performance. The second step in the process is to calcula te three times the RDL to compare with the calculated floor or emissions limit. We use the multiplication factor of 3 to approximate a 99 percent upper confidence interval for a data set of 7 or more values. For comparing to the floor, if three times the RDL were le ss than the calculated floor or emissions limit (e.g., calculated from the UPL), we would conclude that measur ement variability was adequately addressed. The calculated floor or emissions limit would need no adjustment. If, on the other hand, the value equal to three times the RDL were greater than the UPL, we woul d conclude that the calculated floor or emissions limit does not account entirely for measurement variability. If indicated, we substituted the value equal to three times the RDL for the calculated MACT floor (UPL) emissions level. The equation used to determine emission rates for these RDLs is located in the summary tab of each of the statistical analysis spreadsheets with the exception of the Hg statistical analysis spreadsheet. Method 30B mercury stack testing is a performance-based test method and as such is not compatible with the “3 x RDL” procedure described above. And, because the vast majority of emissions data from Hg testing collected under the ICR is derived from Method 30B testing, the procedure was not utilized at all in the Hg statistical anal ysis spreadsheet. The RDL equation that was utilized, in the appropriate spreadsheet, is either Equation 19-1 (if the F factor utilized is

### 10 based on oxygen content, dry basi s) or Equation 19-6 (if the F f actor utilized is based on carbon dioxide content, dry basis) from the EPA’s Meth od 19. Based on representati ve concentrations in the ICR data set, the EPA chose to use an oxygen concentration of 6 perc ent or a carbon dioxide concentration of 9 percent depending on the subcategory. Depending on the fuel type being analyzed (i.e., coal, liquid oil, soli d oil, or syngas), a different F factor was utilized as shown in Table 1.
To convert the calculated RDL values from un its of lb/MMBtu to units of lb/MWh, the EPA derived a conversion factor of 10 million Btu/MW from the 2010 ICR data. This is an average factor derived from data and was n eeded so the minimum RDL’s calculated in accordance with Method 19 could be compared to the output based UPLs in units of lb/MWh. We determined the RDL for each pollutant using data from tests of all the best performers for all of the final re gulatory subcategories (i.e., pooled test data). We applied the same pollutant-specific RDL and emissions limit ad justment procedure to all subcategories for which we established emissions limits. The review cited above resulted in the existing and new MACT floors using three times the RDL value ra ther than the calculated UPL value for the pollutants listed in Table 2.

MACT Floor Analysis Data Set In determining the MACT floor levels of pe rformance for each subcategory, two types of statistical analyses were utilized depending on th e amount of data available from the EGU ICR:

 The basic component of the variability analysis was us ed for all existing floor calculations to reflect variability betw een the emissions levels achieved by the top performers in the respective subc ategory. For smaller data sets (e.g., Subcategories 3 and 7) run-by-run data we re utilized. For larger data sets (e.g., Subcategories 1, 2, 4 and 6), the minimum test average was used.

 The extended component was added to the va riability analysis for pollutants with sufficient data to quantify normal variati ons in unit performance due to various operating factors. These analyses alwa ys utilized test averages (i.e., no run-by-run emissions data sets were used). Table 3 indicates by subcategory and pollutant the form of the variabilit y analysis utilized. The additional data utilized in the extended analyses were filtered so that only those data from emissions tests with the same pollutant control co nfigurations were included. For example, if a company supplied Hg emissions data (i.e., annu al tests conducted on a unit from 2005 through 2009) and the air pollu tion control within the ICR survey, fo r example, indicated the installation of an activated carbon injection (A CI) system and a fabric filter on the unit in 12/2007, only data following installation of the most recent APCD upgrade was used. After excluding each emissions test conducted on a unit prior to installation of the most recent air pollution control upgrade, all available da ta from the ICR was sorted to determine the lowest level of emissions control that was achieved for each unit within each subcategory. Available data for each unit reflecting emissions hi gher than the minimum value were utilized to determine the variabil ity of emissions.

### 11 Table 1. F-Factor and Oxygen Content used in Ea ch Representative Detection Level Equation by Fuel Type and Subcategory

Fuel Type Dry F factor (F d )/O 2 Content (%) Carbon F factor (F c )/CO 2 Content Coal (Subcategories 1 and 2) 9,780 / 6 IGCC (Syngas, Subcategory 3) 2,313 / 9 Liquid Oil (both Subcategories 4 and 6) 9,180 / 6 Solid Oil (Subcategory 7) 9,830 / 6



### Table 2. Pollutants where EPA Substituted the 3 x RDL value for the Calculated RDLs by Subcategory

Existing MACT Floors (lb/MMBtu) Existing MACT Floors (lb/MWh) New MACT Floors (lb/MWh)

Subcategory 1 Sb, Ni Sb, Ni fPM, Metal Total (non-Hg), HCl, Sb, As, Be, Co, Pb, Ni, Se

Subcategory 2 Sb, Ni Sb, Ni fPM, Metal Total (non-Hg), HCl, Sb, As, Be, Co, Pb, Ni, Se Subcategory 3 Sb, Be, Ni Sb, Be, Ni Be, Co, Ni Subcategory 4 None None HCl, HF, As, Be, Cd Subcategory 6 None None None Subcategory 7 Sb, Be Sb, Be HCl, Sb, As, Be, Co, Ni, Se



### Table 3. Variability Analyses Used in Each MACT Floor Subcategory

Basic Component of Variability Analysis (variability across units run-by-run) Basic Component of Variability Analysis

(variability across units test averages) Extended Component of Variability Analysis (variability across best performers and unit level variability test averages)

Subcategories 1 and 2 (Coal) N/A Total and Individual Metals (non-Hg) and SO 2 fPM, HCl, Hg

Subcategory 3 (IGCC, Syngas) All Pollutants N/A N/A

Subcategory 4 and 6 (Liquid Oil) N/A Total and Individual Metals including Hg HCl, HF fPM

Subcategory 7 (Solid Oil) All Pollutants N/A N/A

### 12 In addition to the initial scatter plot an alysis conducted on submitted emissions data, another outlier analysis was performed once the data were entered into the UPL spreadsheet. This outlier analysis (to identif y gross outliers) determined if the maximum test average in a unit’s set of test averages was two orders of magnitude greater than the minimum value for the given unit. Such gross outliers were removed from floor consideration. The third and final level of outlier analyses was the use of Tukey' s Exploratory Data Analysis Model. Only four test averages were excluded fr om the data sets based on the second outlier analysis and no test averages were excluded based on the third outlier analyses. The four removed test averages were all associated with Hg emissions tests and were not used to calculate the Hg floors for Subcategory 1. All of these data we re from Part II stack tests; two of the four excluded data points were submitted with no run-le vel data. Without run-level data, it was not possible to further evaluate the validity of these outliers. The two remaining averages reflect non-detect values from a Method 29 test on two units sharing a common stack. These units also submitted Method 30B run-level data under Part III with emission rates above the detection limit. Because the outlier was due to limitation of the sampling method, these test averages were removed from further analysis. The emission data averages excluded from each respective spreadsheet using the “two orders of magn itude” check and Tukey's Model are shown in Row 42 of their respective UPL spreadsh eet’s columns (where applicable).

Other Data Excluded from MACT Floor Data Sets There were five companies operating six of the oil-fired EGUs required to perform emissions testing by the 2010 ICR that requested permission from EPA to continue their normal operating practice of co-firing No. 6 residual fuel oil with natural gas (i.e., greater than 10 percent natural gas on a heat ba sis) while conducting their tes ting in order to meet the ICR reporting deadline. The EPA informed the companie s in question that they should complete their testing and that EPA might use their emissions data in the final MACT floor calculations. The EPA ultimately chose to exclude emissions data re ported for these EGUs from the data sets used for Subcategory 4 and 5 MACT floor calculations because th eir emissions are not representative of other oil-fired EGUs under the ICR.
One Method 29 test on an oil-fired unit wa s excluded because the testing contractor expressed concerns that the testing had not b een completed in accordance with the reference method. This excluded data was submitted for Fl orida Power and Light’s Port Everglades Station, Unit 4. The MACT floors for new sources are, according to the CAA, based on the emission control that is achieved in practice by the best -controlled similar source, as determined by the Administrator. In one case, the EPA determined th at the unit with the lowest level of emissions for a particular HAP was not the best-contro lled similar source. For the Subcategory 7 fPM lb/MMBtu floor limit, the EPA determined that a source with only a fabric filter and an SCR was not the best controlled source because a si milar unit with a fabric filter, SCR, and a dry scrubber had a very similar level of emissions. Therefore, the EPA determined that the best controlled source was the unit with the most comprehensive set of ai r pollution controls. In other cases as in the new-source MACT floors for Sub categories 1 and 2, there were situations for some pollutants where only a single test averag e and no individual run-leve l data were available for the EGU identified as the best-controlled so urce. In these cases, no em ission variability could be determined based on a single data point. Ther efore, the next best-controlled similar source

### 13 with sufficient data to account for variability was used to determine the new-source MACT standard as presented in Table 4. Additionally, similar to the approach used in the HMIWI rulemaking, if the emission limit for new sources was less stringent than the emission limit for existing sources in the same subcategory, the EPA decided to use existi ng-source limits for new sources. Although the minimum average test run for the best perf orming source resulted in the lowest three

‐ run average test, the 99 percent UPL

‐ based limit incorporated variability between test runs. As the sample size—in this case the number of test runs—gets smaller, the t

‐ statistic increases. When the sample size of test runs is small, and there is a large variability between te st runs, the calculated limit using the UPL approach can be larger than the variability among a larger set of test runs from units in the best performing 12 percent, esp ecially if the performanc e of the best performing units is comparable. Finally, EPA determined that the best cont rolled Subcategory 1 unit for Hg emissions was Logan, Unit 1 (ORIS 10043) because the only units with lower emissions [Spruance Genco, LLC (ORIS 54081), Generators 2a and 2b or Spru ance Genco, LLC, Generators 3a and 3b] are of an atypical design (stoker units ) for the subcategory that does not represent the most recently permitted and constructed units reflecte d in the RACT/BACT/LAER clearinghouse.

MACT Floor Analysis Results Tables 5, 6, 7, and 8 present the new-sour ce and existing-source MACT floor values determined for the EGU source category. Attachme nt B presents the summary tables with mean, UPL, and floor values for new and existing so urces. The data points removed due to being outliers are shown in Attachment C to this memorandum. Attachment D shows the outlier data removed via the scatter plot analysis method. It s hould be noted that all ta bles presented exclude reference to subcategory 5 because no numerical limits were calculated under the MACT floor analysis for this subcategory.

References Bhaumik, D.K. and Gibbons, R.D. 2004. An Upper Pr ediction Limit for the Arithmetic Mean of a Lognormal Random Variable. Te chnometrics, 46(2):239-248. Durrett, Richard (1996). Probability: Th eory and Examples (Second edition).

### 14 Table 4. EU New-source MACT Floor Data Set Substitutions

Pollutant Data Set Substitution

Hg (Subcategory 1) Did not use the data for either Spruance Genco, LLC (ORIS 54081), Gen 2a and 2b or Spruance Genco, LLC, Gen 3a and 3b, are of an atypical design (stoker units) that does not re present the most recently permitted and constructed units reflected in th e RACT/BACT/LAER clearinghouse. Therefore, the run-level data for Logan, Unit 001 (ORIS 10043) were used in the new MACT floor.

Chromium (Subcategory 1 and 2) Did not use the data for Dallman, Unit 34 (ORIS 963) as no run-level data were available; used the run-level data for Cholla, Unit 3 (ORIS 113) in the new MACT floor.

SO 2 (Subcategory 1 and 2) Could not use the data for Stanton, Unit 10 (ORIS 2824) or R. Gallagher, Unit 2 (1008) as no run-level data were available; used the run-level data for Port of Stockton District Energy Facility, Unit 1 (ORIS 54238) in the new MACT floor.

fPM (Subcategory 7) Could not use the data for Manitowoc, Unit 9 (ORIS 4125) because its control configuration does not repr esent the most recently permitted and constructed units reflected in th e RACT/BACT/LAER clearinghouse. Therefore, the run-level data for Nort hside, Unit 1A (ORIS 667) were used in the new MACT floor.15Table 5. Summary of Existing-source MACT Floor Results for Hg and Non-Hg Metal HAPSubcategory Parameter Antimony (Sb) Arsenic (As) Beryllium (Be) Cadmium (Cd) Chromium (Cr) Cobalt (Co)1No. in MACT floor 130 130 130 130 130 13099% UPL of top 12% (i.e., MACTfloor; except where noted)0.80 lb/TBtua0.0080 lb/GWha1.1 lb/TBtu0.020 lb/GWh0.20 lb/TBtu0.0020 lb/GWh0.30 lb/TBtu0.0030 lb/GWh2.8 lb/TBtu0.030 lb/GWh0.80 lb/TBtu0.0080 lb/GWh2No. in MACT floor 130 130 130 130 130 13099% UPL of top 12% (i.e., MACTfloor; except where noted)0.80 lb/TBtua0.0080 lb/GWha1.1 lb/TBtu0.020 lb/GWh0.20 lb/TBtu0.0020 lb/GWh0.30 lb/TBtu0.0030 lb/GWh2.8 lb/TBtu0.030 lb/GWh0.80 lb/TBtu0.0080 lb/GWh3No. in MACT floor 2 2 2 2 2 299% UPL (i.e., MACT floor)1.40 lb/TBtua0.020 lb/GWha1.5 lb/TBtu0.020 lb/GWh0.10 lb/TBtua0.0010 lb/GWha0.15 lb/TBtu0.0020 lb/GWh2.90 lb/TBtu0.030 lb/GWh1.20 lb/TBtub0.020 lb/GWhb4No. in MACT floor 3 3 3 3 3 299% UPL of top 12% (i.e., MACTfloor)13 lb/TBtu0.20 lb/GWh2.8 lb/TBtu0.030 lb/GWh0.20 lb/TBtu0.0020 lb/GWh0.30 lb/TBtu0.0020 lb/GWh5.5 lb/TBtu0.060 lb/GWh21 lb/TBtu0.30 lb/GWh6No. in MACT floor 2 2 2 2 2 299% UPL of top 12% (i.e., MACTfloor)2.2 lb/TBtu0.020 lb/GWh4.3 lb/TBtu0.080 lb/GWh0.60 lb/TBtu0.0030 lb/GWh0.30 lb/TBtu0.0030 lb/GWh31 lb/TBtu0.30 lb/GWh113 lb/TBtu1.4 lb/GWh7No. in MACT floor 5 5 5 5 5 599% UPL of top 5 (i.e., MACT floor)0.80 lb/TBtua0.0070 lb/GWha0.30 lb/TBtu0.0050 lb/GWh0.060 lb/TBtua0.00050 lb/GWha0.3 lb/TBtu0.0040 lb/GWh0.80 lb/TBtu0.020 lb/GWh1.1 lb/TBtu0.020 lb/GWhSubcategory Parameter Lead (Pb) Manganese (Mn) Nickel (Ni) Selenium (Se)Total Non Hg HAPMetalsFilterable PMMercury(Hg)1No. in MACT floor 130 130 130 130 130 130 47c99% UPL of top 12% (i.e.,MACT floor; except where noted)1.2 lb/TBtu0.020 lb/GWh4.0 lb/TBtu0.050 lb/GWh3.5 lb/TBtua0.040 lb/GWha5.0 lb/TBtu0.060 lb/GWh0.000050 lb/MMBtu0.50 lb/GWh0.030 lb/MMBtu0.30 lb/MWh1.2 lb/TBtu0.013 lb/GWh2No. in MACT floor 130 130 130 130 130 130 2d99% UPL of top 12% (i.e.,MACT floor; except where noted)1.2 lb/TBtu0.020 lb/GWh4.0 lb/TBtu0.050 lb/GWh3.5 lb/TBtua0.040 lb/GWha5.0 lb/TBtu0.060 lb/GWh0.000050 lb/MMBtu0.50 lb/GWh0.030 lb/MMBtu0.30 lb/MWh4.0 lb/TBtue0.040 lb/GWhe3No. in MACT floor 2 2 2 2 2 2 299% UPL (i.e., MACT floor)189 lb/TBtub1.80 lb/GWhb2.5 lb/TBtu0.030 lb/GWh6.5 lb/TBtua0.070 lb/GWha22 lb/TBtu0.30 lb/GWh0.000060 lb/MMBtu0.50 lb/GWh0.040 lb/MMBtu0.40 lb/MWh2.5 lb/TBtu0.030 lb/GWh4No. in MACT floor 3 3 3 3 2f4 399% UPL of top 12% (i.e.,MACT floor)8.1 lb/TBtu0.080 lb/GWh22 lb/TBtu0.30 lb/GWh109 lb/TBtu1.1 lb/GWh3.3 lb/TBtu0.040 lb/GWh0.00080 lb/MMBtu0.0080 lb/MWh0.030 lb/MMBtu0.30 lb/MWh0.20 lb/TBtu0.0020 lb/GWh6No. in MACT floor 2 2 2 2 1f2 299% UPL of top 12% (i.e.,MACT floor)4.9 lb/TBtu0.080 lb/GWh20 lb/TBtu0.30 lb/GWh465 lb/TBtu4.1 lb/GWh9.8 lb/TBtu0.20 lb/GWh0.00060 lb/MMBtu0.0070 lb/MWh0.030 lb/MMBtu0.30 lb/MWh0.040 lb/TBtu0.00040 lb/GWh7No. in MACT floor 5 5 5 5 5 5 599% UPL of top 5 (i.e., MACTfloor)0.80 lb/TBtu0.020 lb/GWh2.3 lb/TBtu0.040 lb/GWh9.0 lb/TBtu0.20 lb/GWh1.2 lb/TBtu0.020 lb/GWh0.000040 lb/MMBtu0.60 lb/GWh0.0080 lb/MMBtu0.090 lb/MWh0.20 lb/TBtu0.0020 lb/GWhaBased on 3x the specific testmethod’s recommended detection limit.bBased on a log normal UPL calculation method.cSubcategory 1 used the top 47 data averages to calculate the MACT floor for mercury.dSubcategory 2 used the top 2 data averages to calculate the MACT floor for mercury.eBeyond the floor.fSubcategory 4 and 6’s Total Non Hg HAP Metalsvalue includes Hg emissions in the floor value.16Table 6. Summary of Existing-source MACTFloor Results for Acid Gases HAP SourcesSubcategory Parameter HCl HF SO21Number in MACT floor 130 N/A 13099% UPL of top 12% (i.e., MACT floor;except where noted)0.0020 lb/MMBtu0.020 lb/MWhN/A0.20 lb/MMBtu1.5 lb/MWh2Number in MACT floor 130 N/A 13099% UPL of top 12% (i.e., MACT floor;except where noted)0.0020 lb/MMBtu0.020 lb/MWhN/A0.20 lb/MMBtu1.5 lb/MWh3Number in MACT floor 2 N/A N/A99% UPL (i.e., MACT floor)0.00050 lb/MMBtu0.0050 lb/MWhN/A N/A4Number in MACT floor 3 3 N/A99% UPL of top 12% (i.e., MACT floor)0.0020 lb/MMBtu0.010 lb/MWh0.00040 lb/MMBtu0.0040 lb/MWhN/A6Number in MACT floor 2 2 N/A99% UPL of top 12% (i.e., MACT floor)0.00020 lb/MMBtu0.0020 lb/MWh0.000060 lb/MMBtu0.00050 lb/MWhN/A7Number in MACT floor 5 N/A 599% UPL of top 5 (i.e., MACT floor)0.0050 lb/MMBtu0.080 lb/MWhN/A0.30 lb/MMBtu2.0 lb/MWhaBased on 3x the specific test method’s recommended detection limit.17Table 7. Summary of New-source MACT FloorResults for Hg and Non-Hg Metal HAPSubcategoryParameterAntimony (Sb)Arsenic (As)Beryllium (Be)Cadmium (Cd)Chromium (Cr)Cobalt (Co)199% UPL of top performer (testruns)0.0080 lb/GWha0.0030 lb/GWha0.00060 lb/GWha0.00040 lb/GWh 0.0070 lb/GWhb0.0020 lb/GWha299% UPL of top performer (testruns)0.0080 lb/GWha0.0030 lb/GWha0.00060 lb/GWha0.00040 lb/GWh 0.0070 lb/GWhb0.0020 lb/GWha399% UPL of top performer (testruns)0.020 lb/GWh 0.020 lb/GWh 0.0010 lb/GWha0.0020 lb/GWh 0.040 lb/GWh 0.0040 lb/GWha499% UPL of top performer (testruns)0.010 lb/GWh 0.0030 lb/GWha0.00050 lb/GWha0.00020lb/GWha0.020 lb/GWh 0.030 lb/GWh699% UPL of top performer (testruns)0.0080 lb/GWh 0.060 lb/GWh 0.0020 lb/GWh 0.0020 lb/GWh 0.020 lb/GWh 0.30 lb/GWh799% UPL of top performer (testruns)0.0080 lb/GWha0.0030 lb/GWha0.00060 lb/GWha0.00070 lb/GWh 0.0060 lb/GWh 0.0020 lb/GWhaSubcategoryParameterLead (Pb)Manganese(Mn)Nickel (Ni)Selenium (Se)Total non-HgHAP MetalsFilterable PMMercury(Hg)199% UPL of top performer (testruns)0.0020alb/GWha0.0040lb/GWh0.040 lb/GWha0.0060lb/GWha0.060 lb/GWha0.0070lb/MWha0.00020 lb/GWhe299% UPL of top performer (testruns)0.0020alb/GWha0.0040lb/GWh0.040 lb/GWha0.0060lb/GWha0.060 lb/GWha0.0070lb/MWha0.040 lb/GWh399% UPL of top performer (testruns)0.0090 lb/GWh 0.020 lb/GWh 0.070 lb/GWha0.30 lb/GWh 0.40 lb/GWh 0.080 lb/MWh 0.040 lb/GWh499% UPL of top performer (testruns)0.0080 lb/GWh 0.020 lb/GWh 0.090 lb/GWh 0.020 lb/GWh 0.00020 lb/MWhc0.070 lb/MWh 0.00010 lb/GWh699% UPL of top performer (testruns)0.030 lb/GWh 0.10 lb/GWh 4.1 lb/GWhd0.020 lb/GWh 0.0070 lb/MWhc0.20 lb/MWh 0.00040 lb/GWhd799% UPL of top performer (testruns)0.020 lb/GWhd0.0070lb/GWh0.040 lb/GWha0.0060lb/GWha0.60 lb/GWhd0.020 lb/MWhf0.0020 lb/GWhaBased on 3x the specific testmethod’s recommended detection limit.bEPA chose to use an alternative unit for new MACT floor because it was the lowestemitting tested unit with run-by-run data.cSubcategory 4 and 6’s Total Non Hg HAP Metalsvalue includes Hg emissions in the floor value.dUsed existing MACT Floor’s limit as thenew MACT floor calculated would have been less restrictive than the existing MACT floor.eEPA chose to use an alternative unit for new MACT floor because of boiler size and design.fEPA chose to use an alternative unit for new MACT floor because it was characteristic of the control technology that a newlybuilt unit will employ.18Table 8. Summary of New-source MACT Floor Results for Acid Gases HAP SourcesSubcategory Parameter HCl HF SO21 99% UPL of top performer (test runs) 0.00040 lb/MWhaN/A 0.40 lb/MWhc2 99% UPL of top performer (test runs) 0.00040 lb/MWhaN/A 0.40 lb/MWhc3 99% UPL of top performer (test runs) 0.0020 lb/MWh N/A N/A4 99% UPL of top performer (test runs) 0.00040 lb/MWha0.00040 lb/MWhaN/A6 99% UPL of top performer (test runs) 0.0020 lb/MWh 0.00050 lb/MWhbN/A7 99% UPL of top performer (test runs) 0.00040 lb/MWhaN/A 0.40 lb/MWhaBased on 3x the specific testmethod’s recommended detection limit.bUsed existing MACT Floor’s limit as the new MACT floor calculated would have been less restrictive than the existing MACT floor.cEPA chose to use an alternative unit for new MACT floor because it was the lowestemitting tested unit with run-by-run data.

### A-1 ATTACHMENTS

### 2 Attachment A: Explanation of EPA’s Calcul ation of the Final MACT Floor Values For New and Existing Sources

The EPA received emissions data from i ndustry respondents under the 2010 EGU MACT ICR in a number of different units of measure and had to convert them to a common lb/MMBtu and lb/MWh basis shown in the statistical analys is spreadsheets. The emissions data could have been submitted under Part II of the ICR (histo rical stack testing conducted from 1/1/2005 to 12/31/2009) or from Part III of the ICR (testi ng done in 2010 or 2011 sp ecifically for the EU MACT ICR). While the Part III data was submitted in the units of measure specified by the EPA, the Part II data came in a variety of units of me asure. The procedures used for making these unit conversions on Part II ICR emissi ons data are explained in this Attachment. In addition, the EPA’s procedure for converting a unit’s stack emission data from a lb/MMBtu basis to a lb/MWh basis is also explained below.

Part II Emission Calculations

 The pollutant test results could be entered in to the database as an emission factor (e.g., lb/MMBtu), an emission rate (e.g., lb/hr) and/or a concentrat ion (e.g., μg/dscm) as a run or a test average. Because the MACT floor was calculated using an emission factor (lb/MMBtu), a hierarchy was selected to be able to use as much company-provided data as possible. The hierarch y was the following order:

1. Company-provided emission factor

2. Company-provided emission rate

3. Company-provided concentration

 Calculations were used to calculate the em issions factor (lb/MMBtu) from the provided emission rate or concentration:

o Using the emission rate required that one of the following two sets of data were provided per run:

 The unit load (MW), or

 The fuel flow rate (dry lb/hr) a nd the fuel heating value (Btu/lb)

o The calculations were:

ݐܽ݊ݐݑ݈݈݋݌ ݈ܾ ݎ݄ ܹܯ ܽ݀݋݈ ݐ݊݅ݑ ሺ rate heat unit כ 1
MMBtu /MWhሻ ൌ emission factor lb/MMBtu

ݎ݋ , ݐܽ݊ݐݑ݈݈݋݌ ݈ܾ ݎ݄ ݁ݐܽݎ ݓ݋݂݈ ݈݁ݑ݂ ݈ܾ ݎ݄ ݁ݑ݈ܽݒ ݅݊݃ݐ݄݁ܽ ݈݁ݑ݂ כ ݑݐܤ ݈ܾ כ ݑݐܤܯܯ 1 ݑݐܤ 1,000,000 ݎ݋ݐ݂ܽܿ ݊݋݅ݏݏ݁݉݅ ൌ ݈ܾ
ݑݐܤܯܯ

### 3 o If the units are originally kg/hr, then the following e quation is used to convert kg/hr to lb/hr

ݐܽ݊ݐݑ݈݈݋݌ ݇݃ ݎ݄ כ ݈ܾ ݇݃ 0.453593 ݐܽ݊ݐݑ݈݈݋݌ ൌ ݈ܾ ݎ݄

o Using the concentration required that one of the following two sets of data were provided per run:

 Fuel type and flue gas oxygen content

 Fuel type and flue gas ca rbon dioxide content, and

 Flue gas moisture content, if concen tration was provided on a wet basis.

o The F-factor method used in EPA Test Method 19 was used to calculate an emission factor for each run that provided the necessary data. The following equations were used:

 Equation 19-1: when measurements are on a dry basis for both oxygen and pollutant concentrations

 Equation 19-4: when the pollutant co ncentration is on a wet basis and oxygen concentration is on a dry basis

 Equation 19-6: when measurements are on a dry basis for both carbon dioxide and pollutant concentrations

 Equation 19-8: when pollutant concen tration is measured on a wet basis and carbon dioxide is m easured on a dry basis

o Concentration units were converted to lb /scf based on the following conversions

Concentration Conversions
Concentration units Conversion to ng/scm Conversion to lb/scf gr/scf 2.2883E+09 1.428571E-04 mg/scm 1000000 6.242797E-08 ng/scm * 1 6.242797E-14

μ g/scm 1000 6.242797E-11 *Not used for particulate or mercury conversions.



### o Calculated a Wet_Dry_O2_CO2_Factor

 If dry O 2 

### , factor = ଶ଴.ଽ ଶ଴.ଽି%ைଶ ௖௢௡௧௘௡௧



###  If wet O 2 

### , factor = ଶ଴.ଽ ሺଵି ೑೒ ೘೚೔ೞ೟ೠೝ೐ ೎೚೙೟೐೙೟
భబబ ሻכሺଶ଴.ଽିௗ௥௬ %ைଶ ௖௢௡௧௘௡௧ሻ



###  If dry CO 2 

### , factor = ଵ଴଴ %஼ைଶ ௗ௥௬ ௖௢௡௧௘௡௧

### 4  If wet CO 2 

### , factor = ଵ଴଴ ሺଵି ೑೒ ೘೚೔ೞ೟ೠೝ೐ ೎೚೙೟೐೙೟
భబబ ሻכሺ%஼ைଶ ௗ௥௬ ௖௢௡௧௘௡௧ሻ



### o F-factors**:

 F d 

### = 9,780 dscf/MMBtu (bituminous and subbituminous coal)

 F c 

### = 1,800 scf/MMBtu (bituminous and subbituminous coal)

 F d 

### = 9,860 dscf/MMBtu (low rank virgin coal)

 F c 

### = 1,910 scf/MMBtu (low rank virgin coal)

 F d 

### = 9,190 dscf/MMBtu (fuel oil)

 F c 

### = 1,410 scf/MMBtu (fuel oil)

**If a Part II test report show ed a tested unit firing coal refuse only, and provided the unit’s emissions in units of concentration only, an emission factor was not calculated. This was because Method 19 does not provide F factors for coal refuse-firing.

o Completed the calculation as follows:

ݎ݋ݐ݂ܽܿ ݊݋݅ݏݏ݁݉݅ ݈ܾ
ݑݐܤܯܯ
݊݋݅ݐܽݎݐ݊ܿ݁݊݋ܿ ൌ ݈ܾ ݂ܿݏ ݎ݋ݐ݂ܽܿ െ ܨ כ ݂ܿݏ
ݑݐܤܯܯ ݎ݋ݐܽܿܨ_ܱ2ܥ_ܱ2_ݕݎܦ_ݐܹ݁ כ

With the exception of the calculations for the output-based Hg MACT fl oor standard, the EPA converted a unit’s reported emission rates from a lb/MMBtu basis to a lb/MWh basis using unitspecific heat rates to conver t between the input- (lb/MMBt u) and output- (lb/MWh) based emission factors. Each unit’s heat rate was cal culated by dividing their maximum heat input by the gross summer generating capacity.

In response to public comments the EPA comple ted output-based Hg MACT floor calculations using a different methodology. The EPA received co mments on the proposed rule that the output based Hg standard should reflect the heat rates of the most effi cient units. One commenter stated that the “EPA should not assume a heat rate any higher than 9,854 Btu/kW h in developing a Hg MACT limit in terms of lb/GWh to comply w ith the goal of rewarding energy efficiency.” Commenters had also stated that “... the EPA should simply convert the average Hg emission rate in lb/MMBtu to lb/MWh (or lb/G Wh) based on a reasonable heat rate.”

The EPA agrees with the commenters that Hg calc ulations should be comp leted using a different methodology because of the antagonistic relationship between low Hg emissions and high thermal efficiency in coal combustion that is evident at the lowest emitters in Subcategory 1. This antagonistic relationship is attributable to the high carbon conten t (i.e., high loss on ignition (LOI)) typical of inefficient combustion units and th e affinity of this high-carbon flue gas stream

### 5 for Hg. For example the units achieving the lowest level of Hg emissions in Subcategory 1 were largely stoker-fired units and fluidized bed comb ustors (FBCs). Many of the stoker-fired units and some of the FBCs had approximately 25 to 30 percent lower efficiencies than the most efficient pulverized coal-fired units in the fl oor pool. The best performing unit on a lb/MMBtu basis was a stoker unit with an emission factor half the value of the lowest emitting pulverized coal source. This disparity between thermal effi ciency and Hg removal efficiency increases the intra-unit variability predic ted by the UPL calculation.

For the conversion of the Hg emission rates for the best performing (lowest emitting) sources in Subcategory 1, EPA utilized the average heat rate for the sources in the input based floor pool (i.e., the 47 sources used to set the lbs Hg/MMBtu standard) and maintained the same units and their rankings between the input and output based standards. The numerical value of this average heat rate is 11.18 MMBtu/MWh.

In order to eliminate the mercury-specific statis tical artifact resulting from the disparity between thermal efficiency and mercury removal efficiency exhibited in the lowest emitters in Subcategory 1, prior to completing the UPL calcu lation to set the lb/MWh alternative emission standard, EPA converted the lb/MMBtu emission rates for the lowest emitters to lb/MWh by multiplying by the average heat rate (11.18 MMBt u/MWh) for the sources in the input based floor pool (i.e., the 47 sources used to set the lb s Hg/MMBtu standard) an d maintained the same units and their rankings between the input and output based standards.

### B-1 Attachment B: Summary Tables with Mean, Upper Prediction Limit, and Final MACT Floor Values for New and Existing Sources

Table B-1. Subcategory 1 Existing Sources Summary of UPLs using emission averages ................................................................................B-2

Table B-2. Subcategory 2 Existing Sources Summary of UPLs using emission averages ...............................................................................B-3

Table B-3. Subcategory 3 Existing Sources Summary of UPLs using emission averages ...............................................................................B-4

Table B-4. Subcategory 4 Existing Sources Summary of UPLs using emission averages ...............................................................................B-5

Table B-5. Subcategory 6 Existing Sources Summary of UPLs using emission averages ...............................................................................B-6

Table B-6. Subcategory 7 Existing Sources Summary of UPLs using emission averages ...............................................................................B-7

Table B-7. Subcategory 1 New Sources Summary of UPLs using emission averages ...............................................................................B-8

Table B-8. Subcategory 2 New Sources Summary of UPLs using emission averages ................................................................................B-9

Table B-9. Subcategory 3 New Sources Summary of UPLs using emission averages .............................................................................B-10

Table B-10. Subcategory 4 New Sources Summary of UPLs using emission averages ..............................................................................B-11

Table B-11. Subcategory 6 New Sources Summary of UPLs using emission averages .............................................................................B-12

Table B-12. Subcategory 7 New Sources Summary of UPLs using emission averages .............................................................................B-13

### B-2 Table B-1. Subcategory 1 Existing Sources - Summary of UPLs using emission averages

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu) Number of units in the floor UPL (lb/TBtu) Floor value Units Filterable PM 0.00216 0.0278 130 0.030 lb/MMBtu
Metal total 0.0000179 0.0000453 130 0.000050 lb/MMBtu Antimony (Sb) 2.1004E-07 5.5482E-07 130 0.554824085 0.80 a lb/TBtu Arsenic (As) 3.9963E-07 1.0021E-06 130 1.002124046 1.1 lb/TBtu Beryllium (Be) 4.2310E-08 1.1305E-07 130 0.113047058 0.20 lb/TBtu Cadmium (Cd) 9.7248E-08 2.0328E-07 130 0.203278401 0.30 lb/TBtu Chromium (Cr) 1.1594E-06 2.7159E-06 130 2.715890762 2.8 lb/TBtu
Cobalt 2.8382E-07 7.2317E-07 130 0.723171199 0.80 lb/TBtu Lead (Pb) 5.0430E-07 1.1530E-06 130 1.15298026 1.2 lb/TBtu Manganese (Mn) 1.6328E-06 3.9917E-06 130 3.991746516 4.0 lb/TBtu Nickel (Ni) 1.3248E-06 3.0971E-06 130 3.097081415 3.5 a lb/TBtu Selenium (Se) 1.4124E-06 4.6602E-06 130 4.660200683 5.0 lb/TBtu Mercury (Hg) 1.9429E-08 1.1324E-06 47 1.132429224 1.2 lb/TBtu
HCl 0.000190 0.001586 130 0.0020 lb/MMBtu
SO 2 0.063421 0.144796 130 0.20 lb/MMBtu

a Based on 3x the specific test method’s recommended detection limit.

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor UPL (lb/GWh) Floor value Units Filterable PM 0.021 0.285 130 0.30 lb/MWh
Metal total 0.000187 0.000472 130 0.50 lb/GWh Antimony (Sb) 2.1488E-06 5.6182E-06 130 0.00561823 0.0080 a lb/GWh Arsenic (As) 4.1470E-06 1.0434E-05 130 0.01043371 0.020 lb/GWh Beryllium (Be) 4.3912E-07 1.1778E-06 130 0.00117776 0.0020 lb/GWh Cadmium (Cd) 1.0015E-06 2.1479E-06 130 0.00214787 0.0030 lb/GWh Chromium (Cr) 1.2091E-05 2.9125E-05 130 0.02912466 0.030 lb/GWh
Cobalt 2.9352E-06 7.6633E-06 130 0.00766334 0.0080 lb/GWh Lead (Pb) 5.0486E-06 1.1398E-05 130 0.01139832 0.020 lb/GWh Manganese (Mn) 1.7012E-05 4.1872E-05 130 0.04187177 0.050 lb/GWh Nickel (Ni) 1.4058E-05 3.3263E-05 130 0.03326290 0.040 a lb/GWh Selenium (Se) 1.5062E-05 4.9694E-05 130 0.04969358 0.060 lb/GWh Mercury (Hg) 2.1717E-07 1.2658E-05 47 0.01265789 0.013 lb/GWh
HCl 0.001918 0.016199 130 0.020 lb/MWh
SO 2 0.642155 1.444099 130 1.5 lb/MWh

a Based on 3x the specific test method’s recommended detection limit.

### B-3 Table B-2. Subcategory 2 Existing Sources - Summary of UPLs using emission averages

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu) Number of units in the floor UPL (lb/TBtu) Floor value Units Filterable PM 0.00216 0.0278 130 0.030 lb/MMBtu
Metal total 0.0000179 0.0000453 130 0.000050 lb/MMBtu Antimony (Sb) 2.1004E-07 5.5482E-07 130 0.554824085 0.80 a lb/TBtu Arsenic (As) 3.9963E-07 1.0021E-06 130 1.002124046 1.1 lb/TBtu Beryllium (Be) 4.2310E-08 1.1305E-07 130 0.113047058 0.20 lb/TBtu Cadmium (Cd) 9.7248E-08 2.0328E-07 130 0.203278401 0.30 lb/TBtu Chromium (Cr) 1.1594E-06 2.7159E-06 130 2.715890762 2.8 lb/TBtu
Cobalt 2.8382E-07 7.2317E-07 130 0.723171199 0.80 lb/TBtu Lead (Pb) 5.0430E-07 1.1530E-06 130 1.15298026 1.2 lb/TBtu Manganese (Mn) 1.6328E-06 3.9917E-06 130 3.991746516 4.0 lb/TBtu Nickel (Ni) 1.3248E-06 3.0971E-06 130 3.097081415 3.5 a lb/TBtu Selenium (Se) 1.4124E-06 4.6602E-06 130 4.660200683 5.0 lb/TBtu Mercury (Hg) 1.0672E-06 1.0574E-05 2 10.5740272 4.0 b lb/TBtu
HCl 0.000190 0.001586 130 0.0020 lb/MMBtu
SO 2 0.063421 0.144796 130 0.20 lb/MMBtu

a Based on 3x the specific test method’s recommended detection limit.

b Beyond the floor.

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor UPL (lb/GWh) Floor value Units Filterable PM 0.021 0.285 130 0.30 lb/MWh
Metal total 0.000187 0.000472 130 0.50 lb/GWh Antimony (Sb) 2.1488E-06 5.6182E-06 130 0.00561823 0.0080 a lb/GWh Arsenic (As) 4.1470E-06 1.0434E-05 130 0.01043371 0.020 lb/GWh Beryllium (Be) 4.3912E-07 1.1778E-06 130 0.00117776 0.0020 lb/GWh Cadmium (Cd) 1.0015E-06 2.1479E-06 130 0.00214787 0.0030 lb/GWh Chromium (Cr) 1.2091E-05 2.9125E-05 130 0.02912466 0.030 lb/GWh
Cobalt 2.9352E-06 7.6633E-06 130 0.00766334 0.0080 lb/GWh Lead (Pb) 5.0486E-06 1.1398E-05 130 0.01139832 0.020 lb/GWh Manganese (Mn) 1.7012E-05 4.1872E-05 130 0.04187177 0.050 lb/GWh Nickel (Ni) 1.4058E-05 3.3263E-05 130 0.03326290 0.040 a lb/GWh Selenium (Se) 1.5062E-05 4.9694E-05 130 0.04969358 0.060 lb/GWh Mercury (Hg) 1.1464E-05 1.1213E-04 2 0.11213482 0.040 b lb/GWh
HCl 0.001918 0.016199 130 0.020 lb/MWh
SO 2 0.642155 1.444099 130 1.5 lb/MWh

a Based on 3x the specific test method’s recommended detection limit.
b Beyond the floor.

### B-4 Table B-3. Subcategory 3 Existing Sources - Summary of UPLs using emission averages

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu) Number of units in the floor Floor value Units Filterable PM 1.0772E-02 3.5195E-02 2 0.040 lb/MMBtu
Metal total 2.3539E-05 5.0551E-05 2 0.000060 lb/MMBtu Antimony (Sb) 1.1454E-07 4.2298E-07 2 1.4 a lb/TBtu Arsenic (As) 6.3633E-07 1.4137E-06 2 1.5 lb/TBtu Beryllium (Be) 1.1236E-08 2.5025E-08 2 0.10 a lb/TBtu Cadmium (Cd) 5.9005E-08 1.4769E-07 2 0.15 lb/TBtu Chromium (Cr) 1.2311E-06 2.8173E-06 2 2.9 lb/TBtu Cobalt (Co) 1.3523E-07 1.1354E-06 2 1.2 b lb/TBtu Lead (Pb) 5.9758E-06 1.8860E-04 2 189 b lb/TBtu Manganese (Mn) 1.0094E-06 2.4143E-06 2 2.5 lb/TBtu Nickel (Ni) 2.0434E-06 4.9097E-06 2 6.5 a lb/TBtu Selenium (Se) 1.2342E-05 2.1355E-05 2 22 lb/TBtu Mercury 9.1481E-07 2.4877E-06 2 2.5 lb/TBtu
HCl 1.8795E-04 4.4175E-04 2 0.00050 lb/MMBtu

a Based on 3x the specific test method’s recommended detection limit.
b Based on a log normal UPL calculation method.

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor Floor value Units Filterable PM 1.0886E-01 3.5661E-01 2 0.40 lb/MWh
Metal total 2.3485E-04 4.9940E-04 2 0.50 lb/GWh Antimony (Sb) 1.1355E-06 4.1735E-06 2 0.020 a lb/GWh Arsenic (As) 6.3263E-06 1.3906E-05 2 0.020 lb/GWh Beryllium (Be) 1.1164E-07 2.4580E-07 2 0.0010 a lb/GWh Cadmium (Cd) 5.8654E-07 1.4564E-06 2 0.0020 lb/GWh Chromium (Cr) 1.2376E-05 2.8575E-05 2 0.030 lb/GWh Cobalt (Co) 1.3574E-06 1.1257E-05 2 0.020 b lb/GWh Lead (Pb) 5.8991E-05 1.7941E-03 2 1.8 b lb/GWh Manganese (Mn) 1.0156E-05 2.4517E-05 2 0.030 lb/GWh Nickel (Ni) 2.0345E-05 4.8367E-05 2 0.070 a lb/GWh Selenium (Se) 1.2365E-04 2.1639E-04 2 0.30 lb/GWh Mercury 9.0777E-06 2.4576E-05 2 0.030 lb/GWh
HCl 1.8909E-03 4.4910E-03 2 0.0050 lb/MWh

a Based on 3x the specific test method’s recommended detection limit.
b Based on a log normal UPL calculation method.

### B-5 Table B-4. Subcategory 4 Existing Sources - Summary of UPLs using emission averages

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu) Number of units in the floor Floor value Units Filterable PM 1.3314E-03 2.4893E-02 4 0.030 lb/MMBtu Metal total (including Mercury) 2.4825E-05 7.8679E-04 2 0.00080 lb/MMBtu Antimony (Sb) 1.4555E-06 1.2398E-05 3 13 lb/TBtu Arsenic (As) 4.2018E-07 2.7038E-06 3 2.8 lb/TBtu Beryllium (Be) 4.0680E-08 1.3306E-07 3 0.20 lb/TBtu Cadmium (Cd) 3.8431E-08 2.0859E-07 3 0.30 lb/TBtu Chromium (Cr) 1.1867E-06 5.4468E-06 3 5.5 lb/TBtu
Cobalt 7.0384E-07 2.0771E-05 2 21 lb/TBtu Lead (Pb) 1.1334E-06 8.0993E-06 3 8.1 lb/TBtu Manganese (Mn) 3.3671E-06 2.1030E-05 3 22 lb/TBtu Mercury (Hg) 1.9933E-08 1.8671E-07 3 0.20 lb/TBtu Nickel (Ni) 1.6894E-05 1.0802E-04 3 109 lb/TBtu Selenium (Se) 7.4541E-07 3.2101E-06 3 3.3 lb/TBtu
HCl 1.3813E-04 1.0360E-03 3 0.0020 lb/MMBtu
HF 5.9000E-05 3.9720E-04 3 0.00040 lb/MMBtu

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor Floor value Units Filterable PM 1.3315E-02 2.5344E-01 4 0.30 lb/MWh Metal total (including Mercury) 2.4851E-04 7.8059E-03 2 0.0080 lb/MWh Antimony (Sb) 1.3953E-05 1.1513E-04 3 0.20 lb/GWh Arsenic (As) 4.1225E-06 2.6934E-05 3 0.030 lb/GWh Beryllium (Be) 4.0527E-07 1.2688E-06 3 0.0020 lb/GWh Cadmium (Cd) 3.7605E-07 1.9946E-06 3 0.0020 lb/GWh Chromium (Cr) 1.2081E-05 5.8542E-05 3 0.060 lb/GWh
Cobalt 7.0479E-06 2.0588E-04 2 0.30 lb/GWh Lead (Pb) 1.1062E-05 7.8478E-05 3 0.080 lb/GWh Manganese (Mn) 3.5511E-05 2.2775E-04 3 0.30 lb/GWh Mercury (Hg) 1.8441E-07 1.6744E-06 3 0.0020 lb/GWh Nickel (Ni) 1.6341E-04 1.0106E-03 3 1.1 lb/GWh Selenium (Se) 7.3915E-06 3.1453E-05 3 0.040 lb/GWh
HCl 1.3620E-03 9.8579E-03 3 0.010 lb/MWh
HF 5.8726E-04 3.5975E-03 3 0.0040 lb/MWh

### B-6 Table B-5. Subcategory 6 Existing Sources - Summary of UPLs using emission averages

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu) Number of units in the floor Floor value Units Filterable PM 1.2700E-02 2.1977E-02 2 0.030 lb/MMBtu Metal total (including Mercury) 4.5871E-04 5.6896E-04 1 0.00060 lb/MMBtu Antimony (Sb) 4.4789E-07 2.1463E-06 2 2.2 lb/TBtu Arsenic (As) 2.6443E-06 4.2902E-06 2 4.3 lb/TBtu Beryllium (Be) 7.6624E-08 5.0492E-07 2 0.60 lb/TBtu Cadmium (Cd) 6.6022E-08 2.5659E-07 2 0.30 lb/TBtu Chromium (Cr) 1.3835E-06 3.0666E-05 2 31 lb/TBtu
Cobalt 1.9783E-05 1.1270E-04 2 113 lb/TBtu Lead (Pb) 8.5809E-07 4.8932E-06 2 4.9 lb/TBtu Manganese (Mn) 6.6888E-06 1.9361E-05 2 20 lb/TBtu Mercury (Hg) 2.1831E-08 3.5917E-08 2 0.040 lb/TBtu Nickel (Ni) 4.0120E-04 4.6425E-04 2 465 lb/TBtu Selenium (Se) 9.4374E-07 9.7515E-06 2 9.8 lb/TBtu
HCl 1.2095E-04 1.8416E-04 2 0.00020 lb/MMBtu
HF 2.1756E-05 5.2130E-05 2 0.000060 lb/MMBtu

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor Floor value Units Filterable PM 1.3185E-01 2.1372E-01 2 0.30 lb/MWh Metal total (including Mercury) 5.0411E-03 6.2527E-03 1 0.0070 lb/MWh Antimony (Sb) 4.8254E-06 1.6104E-05 2 0.020 lb/GWh Arsenic (As) 2.6572E-05 7.7602E-05 2 0.080 lb/GWh Beryllium (Be) 7.9423E-07 2.1190E-06 2 0.0030 lb/GWh Cadmium (Cd) 6.3449E-07 2.3752E-06 2 0.0030 lb/GWh Chromium (Cr) 1.4080E-05 2.7391E-04 2 0.30 lb/GWh
Cobalt 2.1952E-04 1.3569E-03 2 1.4 lb/GWh Lead (Pb) 9.0902E-06 7.6756E-05 2 0.080 lb/GWh Manganese (Mn) 6.9665E-05 2.1207E-04 2 0.30 lb/GWh Mercury (Hg) 2.1573E-07 3.6387E-07 2 0.00040 lb/GWh Nickel (Ni) 3.5305E-03 4.0854E-03 2 4.1 lb/GWh Selenium (Se) 9.9111E-06 1.3208E-04 2 0.20 lb/GWh
HCl 1.2018E-03 1.8604E-03 2 0.0020 lb/MWh
HF 2.0860E-04 4.9981E-04 2 0.00050 lb/MWh

### B-7 Table B-6. Subcategory 7 Existing Sources - Summary of UPLs using emission averages

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu) Number of units in the floor Floor value Units Filterable PM 2.4854E-03 7.7373E-03 5 0.0080 lb/MMBtu
Metal total 1.6248E-05 3.3086E-05 5 0.000040 lb/MMBtu Antimony (Sb) 3.8154E-08 8.7808E-08 5 0.80 a lb/TBtu Arsenic (As) 1.4149E-07 2.8119E-07 5 0.30 lb/TBtu Beryllium (Be) 1.8805E-08 4.9371E-08 5 0.060 a lb/TBtu Cadmium (Cd) 9.9768E-08 2.1618E-07 5 0.30 lb/TBtu Chromium (Cr) 3.4205E-07 7.2031E-07 5 0.80 lb/TBtu Cobalt (Co) 3.4111E-07 1.0863E-06 5 1.1 lb/TBtu Lead (Pb) 4.0216E-07 7.4535E-07 5 0.80 lb/TBtu Manganese (Mn) 9.7323E-07 2.2392E-06 5 2.3 lb/TBtu Nickel (Ni) 3.5824E-06 8.9021E-06 5 9.0 lb/TBtu Selenium (Se) 5.0506E-07 1.1126E-06 5 1.2 lb/TBtu Mercury 8.2310E-08 1.5996E-07 5 0.20 lb/TBtu
HCl 1.0296E-03 4.0628E-03 5 0.0050 lb/MMBtu
SO 2 8.0859E-02 2.1346E-01 5 0.30 lb/MMBtu

a Based on 3x the specific test method’s recommended detection limit.

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor Floor value Units Filterable PM 2.6840E-02 8.3421E-02 5 0.090 lb/MWh
Metal total 1.9811E-04 3.6323E-04 5 0.60 lb/GWh Antimony (Sb) 4.1331E-07 7.6573E-07 5 0.0080 a lb/GWh Arsenic (As) 1.6539E-06 4.0507E-06 5 0.0050 lb/GWh Beryllium (Be) 2.1359E-07 4.8671E-07 5 0.00060 a lb/GWh Cadmium (Cd) 1.4616E-06 3.2344E-06 5 0.0040 lb/GWh Chromium (Cr) 5.6987E-06 1.4692E-05 5 0.020 lb/GWh Cobalt (Co) 4.3110E-06 1.0409E-05 5 0.020 lb/GWh Lead (Pb) 5.5763E-06 1.1608E-05 5 0.020 lb/GWh Manganese (Mn) 1.4346E-05 3.4025E-05 5 0.040 lb/GWh Nickel (Ni) 4.7150E-05 1.2121E-04 5 0.20 lb/GWh Selenium (Se) 6.3226E-06 1.3132E-05 5 0.020 lb/GWh Mercury 8.4520E-07 1.6051E-06 5 0.0020 lb/GWh
HCl 1.8168E-02 7.8803E-02 5 0.080 lb/MWh
SO 2 8.3935E-01 1.9019E+00 5 2.0 lb/MWh

a Based on 3x the specific test method’s recommended detection limit.

### B-8 Table B-7. Subcategory 1 New Sources - Summary of UPLs using emission averages

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor UPL (lb/GWh) Floor value Units Filterable PM 0.00224 0.00414 1 0.0070 a lb/MWh
Metal total 0.0000135 0.0000191 1 0.060 a lb/GWh Antimony (Sb) 2.9040E-08 1.5157E-07 1 0.00015157 0.0080 a lb/GWh Arsenic (As) 2.4741E-07 7.9714E-07 1 0.00079714 0.0030 a lb/GWh Beryllium (Be) 1.8323E-08 2.2213E-08 1 0.00002221 0.00060 a lb/GWh Cadmium (Cd) 7.3840E-08 3.6937E-07 1 0.00036937 0.00040 lb/GWh Chromium (Cr) 1.3085E-06 6.3194E-06 1 0.00631940 0.0070 b lb/GWh
Cobalt 1.3748E-07 7.1620E-07 1 0.00071620 0.0020 a lb/GWh Lead (Pb) 8.9650E-07 1.4190E-06 1 0.00141905 0.0020 a lb/GWh Manganese (Mn) 1.3326E-06 3.0511E-06 1 0.00305110 0.0040 lb/GWh Nickel (Ni) 1.0770E-06 3.1608E-06 1 0.00316076 0.040 a lb/GWh Selenium (Se) 1.1974E-07 2.7349E-07 1 0.00027349 0.0060 a lb/GWh Mercury (Hg) 4.6691E-08 1.9899E-07 1 0.00019899 0.000020 c lb/GWh
HCl 0.000113 0.000239 1 0.00040 a lb/MWh
SO 2 0.0912 0.3883 1 0.40 d lb/MWh

a Based on 3x the specific test method’s recommended detection limit. b EPA chose to use an alternative unit for new MACT floor because of the best unit ha ving a single average value (i.e., no run-b yrun data).

c EPA chose to use an alternative unit for new MACT floor because of boiler size and design. d EPA chose to use an alternative unit for new MACT floor because it was the lowest emitting tested unit with run-by-run data.

### B-9 Table B-8. Subcategory 2 New Sources- Summa ry of UPLs using emission averages

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor UPL (lb/GWh) Floor value Units Filterable PM 0.00224 0.00414 1 0.0070 a lb/MWh
Metal total 0.0000135 0.0000191 1 0.060 a lb/GWh Antimony (Sb) 2.9040E-08 1.5157E-07 1 0.00015157 0.0080 a lb/GWh Arsenic (As) 2.4741E-07 7.9714E-07 1 0.00079714 0.0030 a lb/GWh Beryllium (Be) 1.8323E-08 2.2213E-08 1 0.00002221 0.00060 a lb/GWh Cadmium (Cd) 7.3840E-08 3.6937E-07 1 0.00036937 0.00040 lb/GWh Chromium (Cr) 1.3085E-06 6.3194E-06 1 0.00631940 0.0070 b lb/GWh
Cobalt 1.3748E-07 7.1620E-07 1 0.00071620 0.0020 a lb/GWh Lead (Pb) 8.9650E-07 1.4190E-06 1 0.00141905 0.0020 a lb/GWh Manganese (Mn) 1.3326E-06 3.0511E-06 1 0.00305110 0.0040 lb/GWh Nickel (Ni) 1.0770E-06 3.1608E-06 1 0.00316076 0.040 a lb/GWh Selenium (Se) 1.1974E-07 2.7349E-07 1 0.00027349 0.0060 a lb/GWh Mercury (Hg) 1.0726E-05 3.4543E-05 1 0.03454321 0.040 lb/GWh
HCl 0.000113 0.000239 1 0.00040 a lb/MWh
SO 2 0.0912 0.3883 1 0.40 c lb/MWh

a Based on 3x the specific test method’s recommended detection limit. b EPA chose to use an alternative unit for new MACT floor because of the best unit ha ving a single average value (i.e., no runby-run data).

c EPA chose to use an alternative unit for new MACT floor because it was the lowest emitting te sted unit with run-by-run data.

### B-10 Table B-9. Subcategory 3 New Sources- Summa ry of UPLs using emission averages

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor UPL (lb/GWh) Floor value Units Filterable PM 1.5233E-02 7.3966E-02 1 0.080 lb/MWh
Metal total 2.0439E-04 3.5845E-04 1 0.35844614 0.40 lb/GWh Antimony (Sb) 5.3304E-07 1.6941E-05 1 0.01694051 0.020 lb/GWh Arsenic (As) 3.7662E-06 1.3169E-05 1 0.01316932 0.020 lb/GWh Beryllium (Be) 6.1049E-08 1.5247E-07 1 0.00096255 0.0010 a lb/GWh Cadmium (Cd) 3.4277E-07 1.6018E-06 1 0.00160182 0.0020 lb/GWh Chromium (Cr) 6.7312E-06 3.1134E-05 1 0.03113404 0.040 lb/GWh
Cobalt 8.9184E-07 3.1390E-06 1 0.00360955 0.0040 a lb/GWh Lead (Pb) 2.3758E-06 8.6936E-06 1 0.00869363 0.0090 lb/GWh Manganese (Mn) 4.8551E-06 1.7680E-05 1 0.01768028 0.020 lb/GWh Nickel (Ni) 1.4376E-05 2.7198E-05 1 0.06497191 0.070 a lb/GWh Selenium (Se) 9.9489E-05 2.9550E-04 1 0.29549610 0.30 lb/GWh Mercury (Hg) 4.0666E-06 3.2809E-05 1 0.03280946 0.040 lb/GWh
HCl 9.0994E-04 1.0743E-03 1 0.0020 lb/MWh

a Based on 3x the specific test method’s recommended detection limit.

### B-11 Table B-10. Subcategory 4 New Sources-Summary of UPLs using emission averages

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor Floor value Units Filterable PM 9.9560E-03 6.5380E-02 1 0.070 lb/MWh Total Metals (including Mercury) 1.1139E-04 1.4413E-04 1 0.00020 lb/MWh
Antimony (Sb) 3.3944E-06 9.1970E-06 1 0.010 lb/GWh Arsenic (As) 1.6590E-06 1.7190E-06 1 0.0030 a lb/GWh Beryllium (Be) 2.8769E-07 2.9925E-07 1 0.00050 a lb/GWh Cadmium (Cd) 1.4385E-07 1.4963E-07 1 0.00020 a lb/GWh Chromium (Cr) 8.6940E-06 1.7775E-05 1 0.020 lb/GWh
Cobalt 3.4404E-06 2.0932E-05 1 0.030 lb/GWh Lead (Pb) 2.3853E-06 7.8272E-06 1 0.0080 lb/GWh Manganese (Mn) 8.4398E-06 1.3215E-05 1 0.020 lb/GWh Mercury (Hg) 6.4837E-08 9.3613E-08 1 0.00010 lb/GWh Nickel (Ni) 4.9223E-05 8.6803E-05 1 0.090 lb/GWh Selenium (Se) 4.0341E-06 1.4859E-05 1 0.020 lb/GWh
HCl 1.5213E-04 1.6682E-04 1 0.00040 a lb/MWh
HF 1.5661E-04 1.7130E-04 1 0.00040 a lb/MWh

a Based on 3x the specific test method’s recommended detection limit.

### B-12 Table B-11. Subcategory 6 New Sources-Summary of UPLs using emission averages

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor Floor value Units Filterable PM 9.7155E-02 1.3453E-01 1 0.20 lb/MWh Total Metals (including Mercury) 5.0411E-03 6.2527E-03 1 0.0070 lb/MWh
Antimony (Sb) 4.6207E-06 7.7015E-06 1 0.0080 lb/GWh Arsenic (As) 2.5646E-05 5.2717E-05 1 0.060 lb/GWh Beryllium (Be) 7.7019E-07 1.0080E-06 1 0.0020 lb/GWh Cadmium (Cd) 6.0290E-07 1.0847E-06 1 0.0020 lb/GWh Chromium (Cr) 9.3654E-06 1.2084E-05 1 0.020 lb/GWh
Cobalt 1.9888E-04 2.5213E-04 1 0.30 lb/GWh Lead (Pb) 7.8624E-06 2.3734E-05 1 0.030 lb/GWh Manganese (Mn) 6.7081E-05 9.3682E-05 1 0.10 lb/GWh Mercury (Hg) 1.6618E-07 1.8700E-06 1 0.00040 a lb/GWh Nickel (Ni) 3.5205E-03 7.4115E-03 1 4.1 a lb/GWh Selenium (Se) 7.6945E-06 1.7693E-05 1 0.020 lb/GWh
HCl 9.5001E-04 1.1240E-03 1 0.0020 lb/MWh
HF 2.0082E-04 7.1472E-04 1 0.00050 a lb/MWh

a Used existing MACT Floor’s limit as the new MACT floor calculated would have been less restrictive than the existing MACT floor.

### B-13 Table B-12. Subcategory 7 New Sources - Summary of UPLs using emission averages

Pollutant Mean (lb/MWh) UPL (lb/MWh) Number of units in the floor Floor value Units Filterable PM 4.4581E-03 1.7873E-02 1 0.020 a lb/MWh
Total Metals 1.3441E-04 5.5697E-04 1 0.60 b lb/GWh Antimony (Sb) 2.1008E-07 8.4167E-07 1 0.0080 c lb/GWh Arsenic (As) 4.8046E-07 1.2775E-06 1 0.0030 c lb/GWh Beryllium (Be) 6.7508E-08 7.0105E-08 1 0.00060 c lb/GWh Cadmium (Cd) 2.3972E-07 6.2101E-07 1 0.00070 lb/GWh Chromium (Cr) 1.2450E-06 5.9693E-06 1 0.0060 lb/GWh Cobalt (Co) 6.3762E-07 1.5659E-06 1 0.0020 c lb/GWh Lead (Pb) 3.9369E-06 1.3036E-05 1 0.020 b lb/GWh Manganese (Mn) 1.6067E-06 6.1877E-06 1 0.0070 lb/GWh Nickel (Ni) 1.9944E-06 6.3292E-06 1 0.040 c lb/GWh Selenium (Se) 7.0615E-07 8.2187E-07 1 0.0060 c lb/GWh Mercury 7.1153E-07 1.0105E-06 1 0.0020 lb/GWh
HCl 2.1559E-04 2.7169E-04 1 0.00040 c lb/GWh
SO 2 2.4601E-01 3.6175E-01 1 0.40 lb/MWh

a EPA chose to use an alternative unit for new MACT floor because it more characteristic on the control technology that a newly built unit will employ.

b Used existing MACT Floor’s limit as the new MACT floor calculated would have been less restrictive than the existing MACT floor.

c Based on 3x the specific test method’s recommended detection limit.

### C-1 Attachment C: Data Excluded from the Analysis for Existing Sources using the Gross Outlier Method or Tukey Expl oratory Data Analysis Model

The following data were excluded from the MACT floor calculations via the Gross Outlier Method or the Tukey Explorator y Data Analysis Model (see me morandum text for details of these data exclusions):

HAP Plant name and unit ID Emission value test average excluded

Hg Spruance Genco, LLC (ORIS Code 54081) / Spruance Genco Unit 4A 1.62 x 10 -6 lb/MMBtu

Hg Spruance Genco, LLC (ORIS Code 54081) / Spruance Genco Unit 4A 2.10 x 10 -5 lb/MWh

Hg Spruance Genco, LLC (ORIS Code 54081) / Spruance Genco Unit 4B 1.62 x 10 -6 lb/MMBtu

Hg Spruance Genco, LLC (ORIS Code 54081) / Spruance Genco Unit 4B 2.10 x 10 -5 lb/MWh

Hg TIFD VIII-W, Inc. (ORIS Code 1014 3) / Colver Power Project Unit AAB01 4.07 x 10 -6 lb/MMBtu

Hg TIFD VIII-W, Inc. (ORIS Code 1014 3) / Colver Power Project Unit AAB01 3.74 x 10 -5 lb/MWh

Hg Cedar Bay Generating Company L.P. (ORIS Code 10672) / Cedar Bay Station Unit CBA1 2.48 x 10 -6 lb/MMBtu

Hg Cedar Bay Generating Company L.P. (ORIS Code 10672) / Cedar Bay Station Unit CBA1 2.87 x 10 -5 lb/MWh

### D-1 Attachment D: Outlier Data Removed From MACT Floor Consideration after The Scatter plot Method of Outlier Identification



### Using the scatter plot method of outlier identification (described above), ten data averages were removed from MACT floor considerati on. These averages are listed below.

HAP Plant name and unit ID and Report ID Emission value test average excluded

Hg Interstate Power and Light / Burlington, Unit 1 (ORIS Code 1104), Report ID: BGS-Hg-20071010 3.62 x 10 -3 lb/MMBtu

Hg Basin Electric Power Cooperative/ Leland Olds, Unit 1 (ORIS Code 2817), Report ID: LOS Mercury Alstom Demo 5.26 x 10 -3 lb/MMBtu

Hg Basin Electric Power Cooperative/ Antelope Valley Station, Unit 1 (ORIS Code 6469), AVS Mercury Demo 5.09 x 10 -3 lb/MMBtu

Hg Wisconsin Power and Light / Columbia, Unit 1 (ORIS Code 8023), Report ID: COL1-Hg-20071023 6.99 x 10 -3 lb/MMBtu

HCl Allegheny Energy Supply Company LLC / Harrison Power Station, Unit 1 (ORIS Code 3944), Report ID: 9 9.00 x 10 -1 lb/MMBtu

HCl Public Service Enterprise Group (PSEG) / Hudson Generating Station, Unit 2 (ORIS Code 2403), Report ID: EG08009 3.94 x 10 -4 lb/MMBtu

HCl Public Service Enterprise Group (PSEG) / Hudson Generating Station, Unit 2 (ORIS Code 2403), Report ID: EG07044 4.59 x 10 -4 lb/MMBtu

fPM Arizona Public Service Company / Cholla, Unit 3 (ORIS Code 113), Report ID: 21 9.21 x 10 0 lb/MMBtu

fPM Allegheny Energy Supply Company LLC / Harrison Power Station, Unit 1(ORIS Code 3944), Report ID: Report ID: 9 9.76 x 10 1 lb/MMBtu

fPM Wisconsin Electric Power Company / South Oak Creek, Unit 7 (ORIS Code 4041), Report ID: OCPP-PM-B7B8-6.2005 1.52 x 10 1 lb/MMBtu

fPM Wisconsin Electric Power Company / South Oak Creek, Unit 8 (ORIS Code 4041), Report ID: OCPP-PM-B7B8-6.2005 8.63 x 10 0 lb/MMBtu

fPM Indiantown Cogeneration L.P./ Indiantown Cogeneration L.P., Unit AAB01 (ORIS Code 50976), Report ID: 10669-3 2.44 x 10 1 lb/MMBtu

fPM Indiantown Cogeneration L.P./ Indiantown Cogeneration L.P., Unit AAB01 (ORIS Code 50976), Repo rt ID: from Part III testing 3.22 x 10 -6 lb/MMBtu

SO 2 Public Service Enterprise Group (PSEG) / Hudson Generating Station, Unit 2 (ORIS Code 2403), Report ID: HUDU2E2PT2OS1-Coal 1.83 x 10 -1 lb/MMBtu