EPA Annual Cost $28,740,000 Table 15 of TSD

EPA tons per year reduced 10,427 assumes 77.8% capacity factor used by APS (see cap factor tab)

Unit 5

NOx Control Total Annual Cost tpy reduced APS incremental cost

All Options SCR to LNB+OFA* Dominant Options

SCR $39,925,221 11,445 $5,443 $4,770 $5,443

ROTAMIX+ROFA

LNB+OFA+HERT

SNCR + LNB + OFA $11,221,000 6,171 -$178 $3,276

ROFA 

ROTAMIX + LNB 

SNCR + LNB $11,503,000 4,589 $10,185

LNB + OFA $3,447,000 3,798 $552 $979

LNB $1,991,000 1,160 $4,387

ROTAMIX 

SNCR $10,668,000 3,138 $4,120

COS $348,000 633

SCR costs from APS taken from Table 14 of October 2010 TSD (most recent cost estimates)

All other costs taken from Table 5 of TSD, costs dated August 2008

TPY reductions estimated by APS taken from Table 7 of TSD

Dominant Options are shown in Bold Face font, and were determined from the least cost envelope charts

* We also show incremental costs against the technology APS determined was BART for each unit

** EPA determined that controls relying on LNB or OFA (highlighted in grey) will not be effective on Unit 5 due to limitations 
y APS (see cap factor tab), 0.49 to 0.098 lb/MMBtu, heat rate = 7806 mmbtu/hr

EPA incremental cost average cost effectiveness

SCR to SNCR** SCR to LNB+OFA

$2,479 $3,815 $3,488

APS incremenal cost

SCR to SNCR** SCR to LNB+OFA $1,818

$3,522 $4,770

$2,507

$908

$1,716

$3,400

$550

Unit 5 due to limitations in the boiler configuration, as discussed in the TSD (see p 19)
EPA Annual Cost $28,740,000 Table 15 of TSD

EPA tons per year reduced 10,427 assumes 77.8% capacity factor used by APS (see cap factor tab)

Unit 4

NOx Control Total Annual Cost tpy reduced APS incremental cost

All options SCR to LNB+OFA* Dominant Options

SCR $43,587,221 11,445 $6,137 $5,249 $6,137

ROTAMIX+ROFA

LNB+OFA+HERT

SNCR + LNB + OFA $11,221,000 6,171 -$178 $3,276

ROFA 

ROTAMIX + LNB 

SNCR + LNB $11,503,000 4,589 $10,185

LNB + OFA $3,447,000 3,798 $552 $979

LNB $1,991,000 1,160 $4,387

ROTAMIX 

SNCR $10,668,000 3,138 $4,120

COS $348,000 633

SCR costs from APS taken from Table 14 of October 2010 TSD (most recent cost estimates)

All other costs taken from Table 5 of TSD, costs dated August 2008

TPY reductions estimated by APS taken from Table 7 of TSD

Dominant Options are shown in Bold Face font, and were determined from the least cost envelope charts

* We also show incremental costs against the technology APS determined was BART for each unit

** EPA determined that controls relying on LNB or OFA (highlighted in grey) will not be effective on Unit 4 due to limitations 
y APS (see cap factor tab), 0.49 to 0.098 lb/MMBtu, heat rate = 7806 mmbtu/hr

EPA incremental cost average cost effectiveness

SCR to SNCR** SCR to LNB+OFA

$2,479 $3,815 $3,808

APS incremenal cost

SCR to SNCR** SCR to LNB+OFA $1,818

$3,963 $5,249

$2,507

$908

$1,716

$3,400

$550

Unit 4 due to limitations in the boiler configuration, as discussed in the TSD (see p 19)
EPA Annual Cost $12,068,000 Table 15 of TSD

EPA tons per year reduced 4,505 assumes 90.8% capacity factor used by APS, 0.59 to 0.118 lb/M

Unit 3

NOx Control Total Annual Cost tpy reduced APS incremental cost

All Options SCR to LNB+OFA*

SCR $19,962,000 5,057 $13,623 $7,294

ROTAMIX+ROFA $4,858,000 3,809 $19,760

LNB+OFA+HERT $2,961,000 3,713 -$2,168

SNCR + LNB + OFA $4,210,000 3,137 $4,188

ROFA $3,406,000 2,945 -$677

ROTAMIX + LNB $3,536,000 2,753 -$5,125

SNCR + LNB $4,520,000 2,561 $36,094

LNB + OFA $1,055,000 2,465 $165

LNB $897,000 1,505 -$17,781

ROTAMIX $4,311,000 1,313 $30,021

SNCR $1,429,000 1,217 $1,161

COS $314,000 257

SCR costs from APS taken from Table 14 of October 2010 TSD (most recent cost estimates)

All other costs taken from Table 5 of TSD, costs dated August 2008

TPY reductions estimated by APS (see cap factor tab) taken from Table 7 of TSD

Dominant Options are shown in Bold Face font, and were determined from the least cost envelope charts

* We also show incremental costs against the technology APS determined was BART for each unit

** EPA determined that controls relying on LNB or OFA (highlighted in grey) will not be effective on Unit 3 due to limitations 
 factor used by APS, 0.59 to 0.118 lb/MMBtu, heat rate = 2400 mmbtu/hr

EPA incremental cost average cost effectiveness

Dominant Options SCR to SNCR** SCR to LNB+OFA

$12,650 $3,236 $5,398 $3,947

$1,275

$1,527 APS incremenal cost $797

SCR to SNCR** SCR to LNB+OFA $1,342

$4,826 $7,294 $1,157

$1,284

$1,765

$336 $428

$596

$3,283

$1,174

$1,222

ost envelope charts

e effective on Unit 3 due to limitations in the boiler configuration, as discussed in the TSD (see p 19)
EPA Annual Cost $12,114,000 Table 15 of TSD

EPA tons per year reduced 3,806 assumes 91.1% capacity factor used by APS (see cap factor tab)

Unit 2

NOx Control Total Annual Cost tpy reduced APS incremental cost

All options SCR to LNB* Dominant Options

SCR $20,978,000 4,310 $17,821 $7,328 $17,821

ROTAMIX+ROFA $4,191,000 3,368 $18,333 $18,333

LNB+OFA+HERT $2,816,000 3,293 -$2,305 $1,567

SNCR + LNB + OFA $3,851,000 2,844 $6,007

ROFA $2,956,000 2,695 -$3,680

ROTAMIX + LNB $3,508,000 2,545 -$2,752

SNCR + LNB $3,918,000 2,396 $35,000

LNB + OFA $1,293,000 2,321 $496 $496

LNB $922,000 1,573 -$22,669 $478

ROTAMIX $4,277,000 1,425 $4,421

SNCR $3,941,000 1,349 $3,464

COS $314,000 302

SCR costs from APS taken from Table 14 of October 2010 TSD (most recent cost estimates)

All other costs taken from Table 5 of TSD, costs dated August 2008

TPY taken from Table 7, except for tpy values for LNB+OFA and LNB which were mistakenly reported in the TSD, the correcte

Dominant Options are shown in Bold Face font, and were determined from the least cost envelope charts

* We also show incremental costs against the technology APS determined was BART for each unit

** EPA determined that controls relying on LNB or OFA (highlighted in grey) will not be effective on Unit 2 due to limitations 
ed by APS (see cap factor tab), 0.64 to 0.128 lb/MMBtu, heat rate = 1863 mmbtu/hr

EPA incremental cost average cost effectiveness

SCR to SNCR** SCR to LNB

$3,326 $5,012 $4,867

$1,244

APS incremenal cost $855

SCR to SNCR** SCR to LNB $1,354

$5,754 $7,328 $1,097

$1,378

$1,635

$557

$586

$3,001

$2,921

$1,040

orted in the TSD, the corrected values above are based from Table 5-2 of B&V report

e on Unit 2 due to limitations in the boiler configuration, as discussed in the TSD (see p 19)
EPA Annual Cost $11,475,000 Table 15 of TSD

EPA tons per year reduced 4,578 assumes 89.9% capacity factor used by APS (see cap factor tab)

Unit 1

NOx Control Total Annual Cost tpy reduced

All Options SCR to LNB* Dominant Options

SCR $19,334,000 5,134 $18,518 $7,178 $18,518

ROTAMIX+ROFA $4,223,000 4,318 $19,274 $19,274

LNB+OFA+HERT $2,816,000 4,245 -$2,217 $1,608

SNCR + LNB + OFA $3,785,000 3,808 $5,678

ROFA $2,956,000 3,662 -$3,807

ROTAMIX + LNB $3,508,000 3,517 -$2,336

SNCR + LNB $3,849,000 3,371 $35,014

LNB + OFA $1,293,000 3,298 $509 $509

LNB $922,000 2,569 -$3,543 $288

ROTAMIX $4,277,000 1,622 #DIV/0!

SNCR $4,314,000 1,622 $3,431

COS $314,000 456

SCR costs from APS taken from Table 14 of October 2010 TSD (most recent cost estimates)

All other costs taken from Table 5 of TSD, costs dated August 2008

TPY reductions estimated by APS taken from Table 7 of TSD

Dominant Options are shown in Bold Face font, and were determined from the least cost envelope charts

* We also show incremental costs against the option APS determined was BART for each unit. APS calculated incremental cos

** EPA determined that controls relying on LNB or OFA (highlighted in grey) will not be effective on Unit 1 due to limitations 

APS incremental cost 
d by APS (see cap factor tab), 0.78 to 0.156 lb/MMBtu, heat rate = 1863 mmbtu/hr

EPA incremental cost average cost effectiveness

SCR to SNCR** SCR to LNB

$2,423 $5,254 $3,766

$978

APS incremenal cost $663

SCR to SNCR** SCR to LNB $994

$4,277 $7,178 $807

$997

$1,142

$392

$359

$2,637

$2,660

$689

S calculated incremental cost in its comment letters by comparison with combustion controls

on Unit 1 due to limitations in the boiler configuration, as discussed in the TSD (see p 19)
$10,000,000

$15,000,000

$20,000,000

$25,000,000

T

otal A

n

n

ual C

ost of C

o

ntrols

Incremental Cost of NOx Controls on Unit 1 at Four Corners Power Plant based on APS Cost Estimates

Dominant Controls on Least-Cost Envelope: 

(COS, LNB, LNB+OFA, LNB+OFA+HERT, 

ROTAMIX+ROFA, SCR)

$0

$5,000,000

0 1,000 2,000 3,000 4,000 5,000 6,000

tons per year NOx reduced

Inferior Controls: 

(ROTAMIX, SNCR+LNB, ROTAMIX+LNB, 

ROFA, SNCR+LNB+OFA)
$10,000,000

$15,000,000

$20,000,000

$25,000,000

T

otal A

n

n

ual C

ost of C

o

ntrols

Incremental Cost of NOx Controls on Unit 2 at Four Corners Power Plant based on APS Cost Estimates

Dominant Controls on Least-Cost Envelope: 

(COS, LNB, LNB+OFA, LNB+OFA+HERT, 

ROTAMIX+ROFA, SCR)

$0

$5,000,000

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000

tons per year NOx reduced

Inferior Controls: 

(ROTAMIX, SNCR+LNB, ROTAMIX+LNB, 

ROFA, SNCR+LNB+OFA)
$10,000,000

$15,000,000

$20,000,000

$25,000,000

T

otal A

n

n

ual C

ost of C

o

ntrols

Incremental Cost of NOx Controls on Unit 3 at Four Corners Power Plant based on APS Cost Estimates

Dominant Controls on Least-Cost Envelope: 

(COS, LNB+OFA, LNB+OFA+HERT, SCR)

$0

$5,000,000

0 1,000 2,000 3,000 4,000 5,000 6,000

tons per year NOx reduced

Inferior Controls: 

(ROTAMIX, LNB, SNCR+LNB, ROTAMIX+LNB, ROFA, 

SNCR+LNB+OFA, ROTAMIX+ROFA)
$20,000,000 

$25,000,000 

$30,000,000 

$35,000,000 

$40,000,000 

$45,000,000 

$50,000,000 

T

otal A

n

n

ual C

ost of C

o

ntrols

Incremental Cost of NOx Controls on Unit 4 at Four Corners Power Plant based on APS Cost Estimates

Dominant Controls on Least-Cost Envelope: 

$0 

$5,000,000 

$10,000,000 

$15,000,000 

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000

tons per year NOx reduced

Dominant Controls on Least-Cost Envelope: 

Inferior Controls (LNB, SNCR, SNCR+LNB) (COS, LNB+OFA, SNCR+LNB+OFA, SCR)
$20,000,000 

$25,000,000 

$30,000,000 

$35,000,000 

$40,000,000 

$45,000,000 

T

otal A

n

n

ual C

ost of C

o

ntrols

Incremental Cost of NOx Controls on Unit 5 at Four Corners Power Plant based on APS Cost Estimates

Dominant Controls on Least-Cost Envelope: 

(COS, LNB+OFA, SNCR+LNB+OFA, SCR)

$0 

$5,000,000 

$10,000,000 

$15,000,000 

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000

tons per year NOx reduced

(COS, LNB+OFA, SNCR+LNB+OFA, SCR)

Inferior Controls (LNB, SNCR, SNCR+LNB)
Calculation of capacity factors 

From information in 2007 B&V report

Baseline Post-control TPY reduced Max Heat Rate Max Hours ton to lb conv

Unit 1 0.78 0.08 5134 1863 8760 2000

Unit 2 0.64 0.06 4310 1863 8760 2000

Unit 3 0.59 0.06 5057 2400 8760 2000

Unit 4 0.49 0.06 11445 7806 8760 2000

Unit 5 0.49 0.06 11445 7806 8760 2000
Capacity Factor

89.9%

91.1%

90.8%

77.8%

77.8%