U.S. Environmental Protection Agency 

Region 9 

Clean Air Act Permit 

 

 

Supplemental Emissions Analysis – FCPP SCR Project 

Four Corners Power Plant 

Proposed PSD Permit NN 14-01 and Tribal Minor NSR Permit T-002-NN 

July 2014 

 

Introduction 

The U.S. Environmental Protection Agency, Region 9 (EPA) conducted a supplemental emissions analysis to the 

emissions analysis conducted by the Arizona Public Service Company (APS) in its April 2014 Application for a 

Prevention of Significant Deterioration Permit for the addition of selective catalytic reduction (SCR) systems to Units 

4 and 5 at the Four Corners Power Plant (FCPP). The review provided by APS demonstrated that the FCPP SCR 

Project would only cause a significant net emissions increase for emissions of sulfuric acid mist (SAM). In reviewing 

APS’s application, EPA determined that other there were certain instances where emissions could have be calculated 

slightly differently, but did not affect the overall conclusion regarding whether the FCPP SCR Project caused a 

significant emissions increase and a significant net emissions increase for a particular pollutant. The majority of the 

differences between this analysis and the Applicant’s is the emissions factors chosen when CEMS and performance 

test data were not available, as well as minor differences in rounding. This analysis is simply to illustrate an alternative 

calculation method and is not intended to supersede the Applicant’s analysis.
Summary of PSD Applicability – Supplemental Analysis 

Step 1 – Emissions Increases from the Project 

Table 1 Baseline Actual Emission for Existing Units 4 and 5 

Emission Unit NOX SO2 PM PM10 PM2.5 CO VOC H2SO4 Lead GHGs

(CO2e)

Unit 4 12,044 3,836 450.8 904.6 735.9 692.9 83.1 3.41 12.33 5,028,960 

Unit 5 11,986 4,537 237.9 717.5 594.2 692.4 83.1 5.60 12.32 5,029,166 

Totals 24,029 8,373 688.7 1,622 1,330 1,385 166.2 9.01 24.65 10,058,126 

Table 2 Projected Actual Emissions for New and Existing Equipment 

Emission Unit NOX SO2 PM PM10 PM2.5 CO VOC H2SO4 Lead GHGs

(CO2e)

Unit 4 2,391 3,849 366.0 930.9 788.17 695.1 83.4 106.2 12.37 5,045,303 

Unit 5 2,391 4,551 366.0 930.92 788.17 695.1 83.4 106.2 12.37 5,048,817 

Truck Traffic - Delivery of Sorbent 0.00 0.00 0.10 0.02 0.01 0.00 0.00 0.00 0.00 0.00 

Truck Traffic - Delivery of SCR 

Reagent 

0.00 0.00 0.09 0.02 0.00 0.00 0.00 0.00 0.00 0.00 

Silo for Dry Sorbent Storage 0.00 0.00 0.09 0.09 0.09 0.00 0.00 0.00 0.00 0.00 

Silo for SCR Reagent Storage 0.00 0.00 0.21 0.21 0.21 0.00 0.00 0.00 0.00 0.00 

Totals 4,783 8,400 733 1,862 1,577 1,390 166.8 212.4 24.74 10,094,120 

Table 3 Summary Emissions Increases from the Project 

Emission Unit NOX SO2 PM PM10 PM2.5 CO VOC H2SO4 Lead GHGs

(CO2e)

Baseline Emissions 24,029 8,373 688.7 1,622 1,330 1,385 166.2 9.0 24.65 10,058,126 

Projected Actual Emissions 4,783 8,400 732.5 1,862 1,370 1,390 166.8 212.4 24.74 10,094,120 

Emission Increases -19,246 27 43.8 240 247 5 0.6 203.4 0.09 35,994 

Significant Emissions Rate 40 40 25 15 10 100 40 7 0.6 75,000 

Significant Emission Increase No No Yes Yes Yes No No Yes No No 

*Note: For an existing major stationary source undergoing a modification such as this, PSD permitting for GHGs will occur only when the project would also cause a net 

increase in GHG emissions of 75,000 tpy or more on a CO2e basis and greater than 0 tpy on a mass basis. See 40 CFR 52.21(b)(23) and (49)(iv); PSD and Title V 

Permitting Guidance for Greenhouse Gases (March 2011) at 13-15. 
Summary of PSD Applicability – Supplemental Analysis 

Step 2 – Net Emission Increase 

Contemporaneous Emissions Increases and Decreases 

Table 4 Baseline Actual Emissions 

Emission Unit PM PM10 PM2.5 H2SO4

Unit 1 69.8 123.8 96.6 0.2 

Unit 2 81.6 153.4 153.4 0.6 

Unit 3 102.4 241.8 241.8 0.4 

Auxiliary Boiler 0.0 0.0 0.0 0.0 

Totals 253.8 518.9 491.7 1.2 

Table 5 Projected Actual Emissions 

Emission Unit PM PM10 PM2.5 H2SO4

Unit 1 0.00 0.00 0.00 0.00 

Unit 2 0.00 0.00 0.00 0.00 

Unit 3 0.00 0.00 0.00 0.00 

Auxiliary Boiler 0.96 0.96 0.96 0.00 

Totals 0.96 0.96 0.96 0.00 

Table 6 Contemporaneous Emissions Change 

Emission Unit PM PM10 PM2.5 H2SO4

Units 1-3 -253.8 -518.9 -491.7 -1.25 

Auxiliary Boiler 0.96 0.96 0.96 0 

Totals -252.9 -518.0 -490.8 -1.25 
Summary of PSD Applicability – Supplemental Analysis 

Table 7Summary of PSD Applicability for the FCPP SCR Project 

PSD Applicability PM PM10 PM2.5 H2SO4

Significant emissions increases from the Project 43.80 240 247 203.4 

Combined Contemporaneous Emissions Decreases -252.9 -518.0 -490.8 -1.25 

Significant net emissions -209.1 -278.0 -243.8 202.15 

Significant emission rate 25 15 10 7 

PSD Applicable No No No Yes
Emissions Data 

Table 8 Monthly Heat Input Data for Units 1-5, MMBtu (from Air Program Markets Data) 

 Unit 1 Unit 2 Unit 3 Unit 4 Unit 5

Jan-11 972090.516 1308914.82 1036011.81 4818978 4368754 

Feb-11 1124453.03 1030734.33 666763.646 3926055 4452798 

Mar-11 1227565.56 1354241.7 1801061.14 4236866 4243254 

Apr-11 927974.266 1281977.6 1821410.27 4720085 1038010 

May-11 1129553.26 1331767.8 1928686.7 4815280 1754094 

Jun-11 1178500.17 845075.939 1694924.3 4665251 4110498 

Jul-11 1121346.88 1381361.2 1854187.1 5028511 4632886 

Aug-11 1257988.7 1288649.22 1621793.02 4438588 3038607 

Sep-11 1179030.26 1372613.5 1867166.51 4262185 4841997 

Oct-11 490617.163 1055004.91 1148136.48 1605241 4938771 

Nov-11 67836.972 1389108.43 1419915.74 986383 5003720 

Dec-11 1076716.37 1303861.26 1759555.48 4912582 5088454 

Jan-12 1218290.6 1034382.01 1601246.7 4752868 5166560 

Feb-12 929907.257 684297.012 1735158.1 4466424 4768715 

Mar-12 837476.5 1336802.99 167183.652 3277307 4139506 

Apr-12 120848.508 396862.83 943443.692 2527269 2315397 

May-12 802448.104 872440.909 1817017.52 3078124 2870813 

Jun-12 1201318.82 1248913.66 1668151.66 3942563 3990395 

Jul-12 1090000.88 1165597.35 2003676.6 3856303 5158952 

Aug-12 1019637.1 970488.797 1688895.36 3108086 4474533 

Sep-12 1025024.06 885641.113 1970444.52 5106082 4895140 

Oct-12 1396175.5 1376517.68 1900685.96 5315754 5260406 

Nov-12 1034158.81 892990.736 1680220.14 4397283 4152108 

Dec-12 1323045.76 1171672.49 1457425.8 5046099 2522078 

24- Month

Average

(MMBtu/yr)

11876002.5 13489959.1 18626580.9 48645083.5 48613223 

 
Table 9CEMS Data for NOX, SO2, and CO2 from Air Markets Program Data 

NOX SO2 CO2

Unit 4 Unit 5 Unit 4 Unit 5 Unit 4 Unit 5

Jan-11 1204.258 1077.495 455.361 571.180 497874.1365 452325.1813 

Feb-11 921.031 1052.130 363.684 540.970 406053.8316 460984.8022 

Mar-11 993.865 967.569 354.790 432.691 438003.6745 439420.2859 

Apr-11 1138.335 242.510 442.928 127.663 487452.289 107431.4999 

May-11 1178.202 393.311 376.892 186.379 497332.6721 181395.3465 

Jun-11 1172.055 971.580 360.041 356.917 482383.1509 425086.2309 

Jul-11 1288.240 1151.445 392.935 316.025 519431.4656 479118.3647 

Aug-11 1094.550 757.429 345.557 183.445 459014.2091 314207.5846 

Sep-11 987.888 1239.079 317.949 351.512 440974.7981 500663.7621 

Oct-11 395.979 1257.366 149.745 509.158 165996.1737 510949.4237 

Nov-11 205.293 1286.256 102.717 547.630 102129.9583 516927.6906 

Dec-11 1092.236 1328.988 403.492 580.665 508392.2822 526587.5722 

Jan-12 1099.051 1339.212 418.091 577.324 491305.7256 534206.9876 

Feb-12 1039.452 1189.908 413.095 527.710 462087.6933 493910.2861 

Mar-12 732.402 1026.488 276.634 443.344 338812.3769 428612.5194 

Apr-12 598.361 566.123 182.691 237.616 261494.4004 239732.6271 

May-12 779.954 631.291 196.385 254.490 318342.5233 296971.8085 

Jun-12 1016.080 927.832 225.117 295.043 407898.8619 412578.3208 

Jul-12 922.647 1233.955 234.251 307.533 398776.8318 533303.7553 

Aug-12 820.868 1098.172 175.747 274.146 321483.3582 462644.3918 

Sep-12 1382.268 1230.916 310.367 338.736 527718.0706 506085.751 

Oct-12 1421.436 1372.250 367.718 459.174 548625.4889 544583.0249 

Nov-12 1236.066 1023.637 337.976 413.346 454484.7398 429815.459 

Dec-12 1366.603 606.329 468.800 240.792 521850.3398 260789.3219 

24- Month

Average

(tons/yr)

12043.560 11985.636 3836.482 4536.745 5028959.526 5029165.999 

 
Performance Test Results 

Table 10 Filterable PM Performance Test Data, lb/MMBtu 

Year Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 

2011 0.018 0.03 0.048 0.011 0.01 

2012 0.029 0.025 0.021 0.026 0.006 

Average 0.0235 0.0275 0.0345 0.0185 0.008 

Table 11 Sulfuric Acid Mist Performance Test Data, lb/MMBtu 

Year Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 

2011 0.000068 0.00018 <0.000094 0.00014 0.00023 

Emission Factors 

Filterable PM10: 

· 92% of filterable PM emissions (from performance test data above) 

· Source: AP-42 – Bituminous and Subbituminous Coal Combustion, Table 1.1-6 for a baghouse 

Filterable PM2.5: 

· 53% of filterable PM emissions (from performance test data above) 

· Source: AP-42 – Bituminous and Subbituminous Coal Combustion, Table 1.1-6 for a baghouse 

Condensable PM: 

· 0.02 lb/MMBtu + Sulfuric Acid Test Data (lb/MMBtu) 

· Source: AP-42 – Bituminous and Subbituminous Coal Combustion, Table 1.1-5, CPM-TOT, for all 

controls combined with an FGD control, sulfuric acid test data above 

Carbon Monoxide: 

· 0.028 lb/MMBtu 

· Source: AP-42 – Bituminous and Subbituminous Coal Combustion, Table 1.1-3, 0.5 lb/ton for PC 

dry bottom pre-NSPS, 8,776 Btu/coal from Application 

Volatile Organic Compounds: 

· 0.003 lb/MMBtu 

· Source: AP-42 – Bituminous and Subbituminous Coal Combustion, Table 1.1-19, 0.06 lb/ton for 

PC dry bottom, 8,776 Btu/coal from Application 

Lead 

· 0.000507 lb/MMBtu 

· Source: AP-42 – Bituminous and Subbituminous Coal Combustion, Table 1.1-17, for PC dry 

bottom 

Greenhouse Gases: 

· Methane: 0.02425 lb/MMBtu, GWP of 25, 0.60625 lb/MMBtu CO2e 

· N20: 0.003527 lb/MMBtu, GWP of 298, 1.051046 lb/MMBtu CO2e 

· Source: Greenhouse Gas Mandatory Reporting Rule, Table A-1 and C-2 of Part 98 
Projected Actual Emissions 

Table 12 Demand Growth Exclusion (same as Fact Sheet) 

Maximum heat input (MMBtu/hr), both units 14,822 

Maximum heat input (MMBtu/yr), both units 129,840,720 

Baseline heat input (MMBtu/hr), both units 97,258,307 

Future expected capacity factor (without Project-related increases) 89.35% 

Future expected heat input (w/o Project-related increase), both units 116,012,683 

Project related increase in fuel use 0.3% 

Increase in heat input caused by Project-related increase in fuel, both units 348,038 

Heat Input for Determining Projected actual emissions, MMBtu/yr (baseline + 

Project-related, excluding demand growth) 97,606,345 

Table 13 Average Emission Rates for Projected Actual Emissions for Units 4 and 5 

Pollutant Unit 4 Unit 5 Basis

NOX 0.098 0.098 BART FIP limit, 30-day rolling average 

SO2 0.1577 0.1865 

Average emission rate from baseline actual emissions, 

Units 4 and 5 combined 

PM 0.015 0.015 BART FIP limit 

PM10 0.03394 0.03403 

92% of BART FIP + 0.02 lb/MMBtu + 0.00435 lb/MMBtu 

SAM limit 

PM2.5 0.02818 0.02795 

53% of BART FIP + 0.02 lb/MMBtu + 0.00435 lb/MMBtu 

SAM limit 

CO 0.028 0.028 Average emission rate from baseline actual emissions, 

VOC 0.003 0.003 Average emission rate from baseline actual emissions, 

H2SO4 0.00435 0.00435 Proposed BACT limit 

Lead 0.000507 0.000507 

Average emission rate from baseline actual emissions, 

Units 4 and 5 combined 

CO2e 206.76 206.90 

Average emission rate from baseline actual emissions, 

Units 4 and 5 combined