### Wisconsin Electric Power Company’s Ap plication to Install Wet Flue Gas Desulfurization and Selective Catalyti c Reduction Facilities and Associated Equipment On Oak Creek Power Plant Units 5, 6, 7 & 8 for Control of Sulfur Dioxide and Nitrogen Oxide Emissions

Appendix C

Oak Creek Units 5, 6, 7 and 8 NO x 

### /SO 2 

### Emissions Reduction Study

## WE ENERGIES

OAK CREEK UNI TS 5, 6, 7 AND 8

NO x 

## /SO 2 

## EMISSIONS REDUCTION STUDY



# VOLUME 1

TECHNICAL AND APPENDICES

Washington Group International, Inc. Building 510 Carnegie Center Princeton, New Jersey 08540-5287

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### REPORT REVISION PAGE
Project Name: Oak Creek Units 5 - 8 Discipline : All

C l i e n t : W e E n e r g i e s L a t e s t R e v i s i o n : 3

Status Rev. No. Date Prepared By Pages Description of Changes Draft 0 09/08/06 T. Tsui Draft Report for Client Review

Final 1 09/25/06 T. Tsui Final Report

Revision 2 10/12/06 T. Tsui Final Report

Revision 3 04/26/07 A. Crawford Final Report

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### VOLUME 1

TABLE OF CONTENTS

Tab Description Page

1.0 EXECUTI V E SUMM ARY .................................................................................................1 1.1 Background

................................................................................................................. ...........1 1.2 NO x 

### and SO 2 

### Em issions Technology Selection Process........................................................1 1.3 Constructability

........................................................................................................... ...........5 1.4 Project Schedule........................................................................................................... ..........5

2.0 STUDY BASIS

.................................................................................................................... .7 2.1 Design Coal

................................................................................................................ ............7 2.2 Boiler Data

................................................................................................................ .............7 2.3 Oak Creek ESP Outlet Design Conditions .............................................................................8 2.4 Em issions L i m its

........................................................................................................... .........9 2.5 Equipm ent Design Assumptions ............................................................................................9 2.6 Cost Estim ate Assum p tions

.................................................................................................. .9

3.0 DESCRIPT IONS OF EVAL UAT E D SO 2 

### AND NO X 

### CONTROL TECHNOLOGY ................................................................................................................11 3.1 In Furnace NO x 

### Control Technologies ................................................................................11 3.2 Post Com b ustion NO x 

### Control Technology – Selected Catalytic Reduction (SCR) ...........13 3.3 SO 2 

### Control Technologies ...................................................................................................16 3.4 Multi-Pollutant (NO x 

### , SO 2 

### and Mercury) Control Technology ...........................................23

4.0 NO X 

### CONTROL TECHNOLOGY EVALUATION ......................................................30 4.1 Evaluation Criteria

........................................................................................................ .......30 4.2 Technology Evaluation Results of Selec tive Catalytic Reactor (SCR) System ..................31 4.3 Elim ination of Hot Side SCRs use on Units 5 & 6 ..............................................................32 4.4 Cold-Side and Tail End SCR Industry Experience ..............................................................33 4.5 Technology Evaluation Results of Mobotec R O FA/ROTAMIX System ............................34 4.6 Technology Evaluation Results of Mitsui Babcock NOxStar System.................................35 4.7 Summ ary of NO x 

### Control Technology Screening Results ..................................................35

5.0 SO 2 

### CONTROL TECHNOLO GY EVALUATION .......................................................39 5.1 Evaluation Criteria

........................................................................................................ .......39 5.2 Technology Evaluation Results of Wet Lim e st one Forced Oxidation (LSFO) Process ...................................................................................................40 5.3 Technology Evaluation Results of Li m e Spray Drying (LSD) / Fabric Filter (FF) S y stem

............................................................................................................ ....41 5.4 Technology Evaluation Results of Circ ulating Fluid Bed Scrubber (CFB)/ Fabric Filter (FF) System

..................................................................................................... 42 5.5 Summ ary of SO 2 

### Control Technology Evaluation Results ..................................................43

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### TABLE OF CONTENTS (Cont'd)

Tab Description Page

6.0 MULTI-POLLUTANT (NO X 

### /SO 2 

### ) CONTROL TECHNO L OGY EVALUATION ..................................................................................................................44 6.1 Technology Evaluation Results of J-Power ReACT System ...............................................44 6.2 Technology Evaluation Results of PowerSpan ECO Syste m ..............................................45 6.3 Summ ary of Multi Po llu tant Cont ro l Technology Evaluation Results ................................45

7.0 SO 2 

### AND NO X 

### COMBI N ED SYSTEM EVALUATION ...............................................47 7.1 Case 1 LSFO and Tail-end SCRs for all Four Units ...........................................................47 7.2 Case 2 LSFO and Cold-side SCRs for all Four Units .........................................................49 7.3 Case 3 LSFO for all Four Units, Cold-side for 5&6, and Hot-side SCRs for 7&8 ............51 7.4 Case 4 LSFO for all Four Units, Tail-end SCRs for 5&6, and Hot-side SC Rs for 7&8 ........................................................................................................5 2 7.5 Com p arison of Cases 1 to 4

................................................................................................. 55

8.0 CONCLUSIONS AND RE COMMENDATIONS ...........................................................56 8.1 Process Selection

.......................................................................................................... .......56 8.2 Site and New Plant Area Considerations .............................................................................57 8.3 Construction Considerations

................................................................................................ 59

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### 1.0 EXEC UTIVE SUMMARY

1.1 Backgrou n d
We Energies' Oak Cree k plant is located on th e shore of Lake Michig an, 20 m iles south of Milwaukee. The plant, located on a 400-acre site , consists of 5 operating Units; 5, 6, 7 and 8 are coal fired w h ile Unit 9 is a com bustion turbine Unit. The fuel used in Units 5-8 is PRB coal. These Units were initially designed to burn eastern bitu m i nous coal, and since have switched to PRB coal to reduce SO 2 

### em issions in acco rdance with W e Energies' e m issions-red u ction p r ogram . Units 5, 6, 7 and 8 are 1959, 1961, 1967 & 1968 vintages, respectively. Units 1-4 have been retired. The coal is supplied to the plant by Union Pacific unit tr ains. Average coal use varies between 5,000 to 10,000 tons per day, based on the dispatch load requirem e nts.

Units 5 and 6 have Foster W h eeler arch-fired furn ace steam generato rs. Units 7 and 8 are Com bustion Engineering corner-fired units. Steam production is at 2400 psig and 1050 ° F. Each Unit has a tu rbine gen e ra tor, which p r oduces e l ec tr ic generation at 18 kV. Step-up transfor m e rs raise supply power to the grid to 138 kV (Unit 5) and 230 kV (Units 6, 7 and 8).

Electrostatic precipitators rem ove fly ash from the flue gas prior to discharge to the atmosphere at the chim neys. Two chimneys are p r ovided, one each for 2 b o iler Units. Once throug h cooling with water from Lake Michigan cools the e xhaust steam at the surface condensers.

Currently We Energies is expanding Oak Creek ge neration through construction of tw o supercritical 615 M W coal-fired Units just nort h of the existing plant. These Units are equipped with SCRs for NO X 

### reduction and lim estone forced oxidation (L SFO) system s for SO 2 

### rem oval. The bi-product of the LSFO system s will be gypsum of wallboard p r oduction qu ality.

1.2 NO x 

### and SO 2 

### Emissions Technology Selection Process
The objectiv e of this stu dy was to select the m o st cost-effective, techn i cally and comm ercially viable processes for SO 2 

### and NO x 

### em issions control at Oak Creek for Units 5, 6, 7 and 8.

Washington Group International (Was hington G r oup) visited the site a nd obtained the pertinent site data through observation of the pl ant, discussions with plant pers onnel, and through co llection of the applicable docum e ntation. W e Energies provided the plant design data in cluding the data required for econom i c evaluation. The following processes were considered for evaluation in this Study, based on potential to reach the required em ission rates:

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### A. SO 2 

### Re m o val (FGD) Processes

• Lim e stone Forced Oxidation (LSFO)

• Lim e Spray-Dryer with Baghouse (LSD)

• Circulating Fluid Bed with Baghouse (CFB)

B. NO X 

### R e m o val P r oces ses

• Mobotec R O FA / ROTAMIX

• Mitsu i NOxStar

• Foster W h eeler Low NO x 

### Burners

• SCR (Hot Side, Cold Side, and Tail-end)

C. Multi-pollutant Processes

• J-Power ReACT Technology

• PowerSpan ECO Technology

These processes represent m a ture, comm ercially well-proven technologie s, while others are dem onstrated technologies but do not possess the sam e level of comm ercial experience. The not-som a ture technologies were considered with the v i ew that if th e evalua tion results ind i c a te overwhelm ing econom i c benefits with their use, that m a y justify taki ng the technology risks associa t ed w ith se lec ting them

. The plant costs were established for each of these processes using W a shington Group' s EPRI program IECCOST. The IECCOST program provides order-of- m agnitude cost es tim ates that a r e useful for comparing and screening alternative technologies. The capital costs in the IECCOST
program are based on historical cost data and recent equipm ent cost s, driven by m a ss balances for the particular Units. Adjustm e nts to the base IEC C OST output were m a de based on conceptual
genera l ar ra ngem e nts f o r the Oak-Cr eek site as w e ll a s othe r s ite -spec i f i c consider atio ns. Additio nal cost inputs were obtained from vendors and were factored into the cost estim ates.
The IECCOST program also develop s fixed and va riab le operating and mainten a nce costs for each

em ission-control process. This study also ev aluated predicted perform a nce, reliability, and availability f o r each of th e process e s considered. The total estim a ted capital cos t s, operating and

m a intenance costs, levelized annual costs, and tota l evaluated costs were developed. C o sts presented in this report are in le velized 2006 dollars. Costs details are pr esented in Sections 4 to 7 of this Report. A summ ary of t h e com p arative cost inform ation is presented below.

In addition to the cost comparison, other factors re lating to the com p eting t echnologies were used in the se lection process to d e term ine the m o st techni cally and co mmercially viab le system. To quantify these facto r s , a num erical rank ing pr ocess was used based on the following:

• Technology

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### • Constructability

• O&M

• Comm ercial Risk

• Perform a nce Margin

• Stable Long-term Market for Byproduct (SO 2 

### system s)

The results of both the cost estim a ting and tec hnology ranking process ar e shown in the tables below:

A. SO 2 

### Re m o val System s The LSFO system is the preferred tec hnology choice when com p ared to SDA and CFB syste m s based on total evaluated cost.

System
Cost $ M L S F O S D A C F B

C a p i t a l C o s

t 3 1 0

. 8 3 3

4

. 8 3 1 3

. 2 L

e

v

e l i z e d O & M 2 8

. 3 4 3

. 4 4 1

. 4 Total Evaluated C o s

t 5 8

5

. 3 7 5

5

. 6 7 1 5

. 0 E v

a l u a t

e

d Rank* 2 3

. 0 1 8

. 0 1 8

. 0

Notes : Costs are for all four Units. LSFO is located down s

tream of cold-side SCRs. *Denotes that higher number is more favorable



### B. NO x 

### Re m o val System s
Based on the lack of demonstrated ability to achieve th e desired NO X 

### em ission reductions with the Mobotec and Mitsui tec hnologies, they were elim inated from further consideration. Hot-side SCR on Un its 5 & 6 cannot be c onstructed without a

m a jor reconstruction of the units from the econo m i zer throu gh the electrostatic precip itator. The outage im pact of this constru c tio n is estim a ted to exceed $200 m illio n, so this op tion was eliminated. Hot-side SCRs on Units 7 & 8 have si gni fi cant l y more di ffi cul t re trofit construction than st andard insta lla tions , which would increase the estim ated total evaluate d cost (TEC) when com p ared with other SCR options. The curren t estim a te f a vors ta il-end SCR, but this dec i sion will be

exam ined further during detailed engin eering, and therefore tail-end SCR is the basis f o r the estim ate co mparisons in this r e por t.

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Syste m

Cost $ M SCR Hot Si de 7 & 8* Cold Si de 5 & 6 SCR Cold Si de (All Units ) SCR Tail End (All Units ) Capital Cost 241.9 190.5 178.6 Levelized O&M 22.6 19.8 12.9 Total Evaluated Cost 4 7

9

. 1 3 8

2

. 3 3 0

3

. 7 Evaluated Rank 19 20 22 *Including $18M power penalty.



### C. Multi-Pollutant Technologies The ReACT system from J-Power is a Japanese technology with lim ited operating experience. The ability o f the ReACT system to m eet Oak Cr eek' s NO x 

### -removal requirem e nts has not been dem onstrated in la rg e scale. The m a rket for the sulfuric acid byproduct is saturated, and other disposal options are not available. Further, total evaluated cost is not significantly di fferent from the selected option, and is subject to more uncertainty due to the early developm ent stage of the technology. The PowerSpan ECO system reduces both SO 2 

### and NO x 

### . This technology has currently been dem onstrated at a 50 M W scale. The planned next-generation application of this technology is for a pl ant in the 200 MW r a nge. Application of this technology for a plant the size of Oak Creek is not anticipated in the required tim efra m e , s o its use at Oak Creek would be first-of-a-kind, and would entail significant technology risk. The total eval uated cost of PowerSpan ECO c o m p ared to LSFO and tail-end S CR differs by le ss than 6%, which is not considered significan t g i ven the accuracy of the curren t estim a tes. Further, due to the early developm ent stage of the t echno log y, the Power S pan estim ate is sub j ec t to m o re uncertainty.

D. Technology Recommendation The recommended technology is a combination of LSFO and SCR on units 5 through 8. The tail end SCR locatio n is preferred, and will b e verified du ring detailed design.

Key considerations for this selection:

LSFO Process :

• Has the highest ranking base d on the evaluation criteria

• Can achieve the highest SO 2 

### e m ission reduction efficiency (up to 98%)

• Provides the greatest fuel flexibility

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### • Provides opportunity for shared sa vings with the Elm Road project

SCR Process :

• Has the highest ranking ba sed on evaluation criteria

• Has the m o s t comm ercial experience and industry acceptance

• Achieves high NO x 

### reduction efficiency

• Provides fuel flexibility

1.3 Constructability

A num b er of different system arrangem ents were consider ed, with the inte nt of locating the new equipm ent as close to the existi ng U n its as possible, and m i nim i zi ng the cost of running flue gas ductwork f r om the existing plan ts to the new equ i pm ent. Ultim ately it was determ ine d that the on ly practical location for the new equipm ent, for all four Units, is in the open ar ea to the south of the plant. The study determ ined that there is adeq u a te space in th is area to accommodate the new

em issions reduction system

. Constructability issues were a l so addr essed, inc l u d ing: tie- ins to exis ting plant with minim a l interruptions to operations, construction laydown ar ea requirem e nts, barge unloading f a cilities, crane access, equipm ent unloading at the d o ck, labor availab i lity, c onstruc tion sequence an d schedule. It

m a y be desirable to bu ild a tem porary dock on the lakeshore adjacen t to th e new facilities to facilitate shipping m odul arized equipm ent.

The m o st practical construction sequ ence will be from west to east, Unit 8 first on the West Side with Units 7

, 6, and 5 f o llowing towa rds the e a st. This will f a cilita te equ i pm ent m ovem e nt and crane access. Laydown and preassembly areas, and craft parking areas were id entified southwest and west of the new plan t area. There is ad equ a te space av ailable for the construction laydown purposes. T h e interconnecting ductwork from the exis ting Units to the ne w equipment has been routed and determ ined to be constructible from the east side of the existing Units, without interruptions to ongoing operations.

Although further study is required regarding labor issues, base d on the currently available inform ation it appears that adequate labor will be available to m a n the pr oposed construction in the Oak Creek project tim e fram e

.
1.4 Project Schedule
A prelim inary project developm ent schedule ha s been prepared, identifying key m ilestones necessary to m eet the co nsent-de cree-required in-service dates. The schedule projects that in 2007 enginee r ing will comm ence and per m its will be obtained. F u ll pro j ec t Notice

- to -Pro ceed is projected to occur by 1 January 2008. Early site activities in 2008 would i nvolve site preparation includ ing th e dem o lition and relo cation of underground utilities. Perm anent plan t equipm ent facility construction is scheduled to start in March 2009 to m i ni m i ze site construction overlaps and interferences and com p e tition for labor with th e Elm Road fa cility c onstruction. The schedule

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### projects commercial operation of Units 7 & 8 by 1 June 2012, and Units 5 & 6 by 15 Nove m b er 2012, which m eet the required cons ent decree in-service dates.

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### 2.0 STUDY BASI S

The designs and analyses contained in this report are based on the plant inf o rm ation supplied by We Energies, d a ta gath ered during visits to the station, and reason able assum p tions and extrapolations from previous studies. This se ction summarizes the design data us ed for the technical and economic analyses of the wet and dry FGD system s, J-Powe r ReACT sy stem , Power S pan ECO s y stem , Mobotec R O FA/ROTAMIX, Mitsui Babcock NOxStar, and SCR as they would be applied to the various conf igurations at the Oak Creek plant.

2.1 Design Coal
For this study, 100% Pleasant Prairi e Power Plant (P4) Design PRB coal serves as the design basis coal.

The ultim ate analys is of the P4 design -basis f u el is provided in Table 2-1.

Table 2-1. C o al Analysis

I t

e m U n i t s P R B C o a l Ultimate Analysis C a r b

o

n % 4 9

. 2

8 H

y

d r

o

g

e n % 3

. 6

5
N i t

r o

g

e n % 0

. 7

0 O

x y

g

e n % 1 1

. 1 0 S u l f u r % 0

. 5

0 C h l o r i n

e % 0

. 0

2 W

a t

e r % 2 9

. 9

0 A

s

h % 4

. 8

5 T o

t a l % 1 0 0 HHV, Btu/lb 8,677



### 2.2 Boiler Data
The existing Oak Creek Power Plant is com p rised of four (4) pulverized coal fired boilers. At current boiler conditions, Units 5 and 6 operate at approxim a tely 85% MC R when firing 100% PRB coal and at 100% MCR when supplem ented by natu ral gas. Units 7 and 8 can reach the m a xi m u m continuous rating (MCR) while firing PRB coal.

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### The operating conditions for Units 5, 6, 7 and 8 wh en burning PRB coal are provided in Table 2-2.

Table 2-2. U n it Design Data

Boiler Units 5 a nd 6 Units 7 a nd 8 S t

a t

u

s E x i s

t i n

g Exist i n

g Gross Rating, M W 522 669 Net Rating, MW 500 641 Gross Unit Heat Rate, Btu/kWHr 9,945 9,666 Net Unit Heat Rate, Btu/kWHr 10,376 10,085 Capacity Factor, % 70 70 Excess Air Downstream of Economizer, % 25 20 Air Heater Leakage, % 12 12 Stack NO x Emissions, lb s/MMBt u 0.2 0.15 Flue Gas Temp. at ESP Outlet, ° F 2 9

5 2 8

6 Particulate Loading At ESP Outlet, lb/MMBtu (*) 0.022 – 0.030 0.017 –0.094

Note : (* ) Per St ac

k Tes t Data.



### 2.3 Oak Creek ESP Outlet Design Conditions
Table 2-3 summarizes the flue gas flow rates for the four Oak Creek units. The gas flow rates and

com positions are based on the existing ID fan inlet conditions. The NO x 

### and fly ash data are based on stack m easurem ents.

Table 2-3. Oak Creek Flue Gas Conditions at the ID Fan Inlet

Units 5 & 6 Units 7 & 8
S C F M 1

, 3 2

0

, 0

0

0 1

, 5 8

4

, 0

0

0 Flue Gas Flow A C F M 2

, 0

2

5

, 0

0

0 2

, 4

0

1

, 0 0

0 Oper. Pressure In. w.c. -12 -12 Temperatu r e ° F 2 9

5 2 8

6 O 2 l b s

/ h r 3 7

2

, 5

1 6 4 0

1

, 3 6

5 CO 2 l b s

/ h r 1

, 0 8

0

, 6

6

2 1

, 3 4

5

, 6

5

8 N 2 l b s

/ h r 4

, 1 8 2

, 2

0

5 5

, 0

0

1

, 9 2

0 HC l l b s

/ h r 1 2 3 1 5 3 SO 2 l b s

/ h r 5

, 9

7

6 7

, 4

4

1 H 2

O l b s

/ h r 4 1 4

, 4

7 1 5 1 4

, 1 2 0 Fly Ash lbs/hr 156 194 Total (Gas only) lbs/hr 6,056,109 7,270,851

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### 2.4 Emissions Limits
The SCR and FGD system s are designed to m eet the followin g NO x 

### and SO 2 

### em ission lim its.

• NO x 

### 0.07 lbs/MMBtu

• SO 2 

### 0.07 lbs/MMBtu

2.5 Equipment Design Assum p tions
The key assum p tions for this study include the following:

• All the wet or dry FGD system s will be lo cated on the South Side of the plant.

• 29% aqueou s ammonia will be us ed as the r eage n t f o r the Re ACT, ECO and SCR syste m s.

• Delivery of reagen t and rem oval of by-product, w ill b e by tru c k.

• The new equipm ent will be designed and installe d so that it d o es not obstr uct

m a intenance and operation access to the existing plant du ring construction or af

ter cons tru c tion is complete.

• The existing ID fans will not be adeq uate for the increased flue gas system pressure drop through the wet or dry F GD syste m , so new booster fans will be required.

• The existing boiler furnaces, heat recove ry areas, and all the com ponents in the flue gas path to the existing ID fans n eed not be stiffened due to any transient conditions that m a y occur with the in stallation and operation of the new

em ission red u ction equ i p m ent.

• The existing auxiliary electric sys t em will not b e adequate to supply the additional electrical load im posed by th e new wet or dry FGD equipm ent. Two new auxiliary transform e rs located on the W e st Side of the tur b ine buildin g will supply power to the new e m ission reduction equipm ent.

• Ductwork f r om the existing induced f a ns to the n e w FGD equipm ent will be

m a de of carbon steel, and insulated.

2.6 Cost Estimate Assumptions

The economic criteria and costs provided in Table 2-4 were used to generate the capital and operating cost estim a tes in this report.

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### Table 2-4. E c onomic Criteria

V

a r

i a b l e U n i t s V a l u e Econo mic Cri t e

r ia Discount Rate (MAR) % 7.5 AFUDC Rate % 1 0

. 3 Construction Period Y e a r

s 3 First Year Fixed Charge Rate % 19.2 Levelized Fixed Charge Rate (FCR) % 14.4 Levelized Fixed Charge Rate (FCR, constant $) % 10.5 Service Life For Units 5 & 6 Years 15 Service Life For Units 7 & 8 Years 30 Start-Up Date Y e a r 2 0

0

9 Inflation Rate % 3

. 0 Land Cost (@ St art-Up Date) $ 0 Power Outage Days (1 ) Days 0 Cost Basis Y e a r 2 0

0

6 Construction Labor Rate $/hr 50.00 Prime Contracto r 's Markup ( %

of

equip. cost) % 10 Reagent Bulk St orage Days 30

O p e r at

i n g C o st D a t a FGD Ope r ating Labor Rate $/hr 33.0 Power Cost Mills/ k W

h 4 0

. 0 Replacement Power Cost Mills/ k Wh 40.0 Steam Cost - high pressure $/1000 lbs 5.50 Methane Cost $/1000 scf 8.00 Activated Coke Cost $ / t o

n 6 0

0 Sulfuric Acid Byproduct Price $/ton 30 Limestone Delivered Cost $/ton 15 Pebble Lime Delivered Cost $/ton 60 Ammonia Delive r ed Cost (as 29 % aqueous so lut

i on) $/ton 180 Hydrogen Peroxide (as 50 %

aqu eous solution) $/ton 318 ATS (as 60 %

aq ueous solution) $/ton 180 Ammonia Sulfat e By Product Credit $/ton 190 Gypsum Revenue $ / t o

n 2 Waste Disposal (landfill) $ / t o

n 3 5 Water Cost: Fresh Water $/1000 gal 0.40 Blowdown Water $/1000 gal 0.00 Cooling Water $/1000 gal 0.16

(1) Power Outage Days – For this study it has bee n assumed that t he tie-ins of wet or dry FGD equi pment and NO x equipment can be complete d during a future scheduled 5 to 6 weeks outage period (no powe r generation lost d u ring constructio n ).

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### 3.0 DESC RIPTIONS OF EVAL UATED SO 2 

### AND NO X



### CONTROL TECHNOLOGY

3.1 In Furnace NO x 

### Control Technologies
Mobotec ROFA/ROTAMIX System

Mobotec' s Rotating Opposed Fire Air (ROFA) proce ss utilizes booster fans to supply high velocity air to distrib u tion boxes placed at sp ecific lo ca tions around the furnace. These boxes are lo cated
asymm e trically n opposite sides of the boiler. A dam p er is provide d at each ROFA box to control the am ount of high velo city air go in g to the box. Th e flue gas volum e in the furnace is set in rotation due to the as ymm e trically placed box es and air no zzles. The com bustion g a ses m i x well with the added high velocity combustion air, m a king a com bustion gas swirl. This generates turbulence and rotation in the entire furnace. Rotation prevents lam i nated flow and the whole volu m e of the furnace can be used more effectively for the co m bustion process resulting in lower output NO x 

### . The ROFA swirl helps reduce the m a xim u m temperatu r e of the flam e combustion zone and increases heat absorption, which in turn im prove s the boiler overall efficiency.

MOBOTEC ROFA/ROTAMIX PROCESS

The Mobotec ROTAMI X system is an advance sele ctive non-catalyst (S NCR) system and has been developed to work in conjunction with th e ROFA system to provide additional NO x 

### reduction. The

sam e kind of asymm e trically p l aced air nozzle is used in th e ROTA MIX techniqu e as in the ROFA system . NO x 

### reduction is achieved by inje ction of liquid ammo nia or urea through lances that are inserted in the ROFA/ROTAMIX nozzles. The high veloc i ty air in the ROFA system carrie s th e reagen t into the cen ter of the furnace. Effective NO x 

### reduction can be achieved with a m i ni m u m

am ount of a mmonia slip.

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### The ROTAMIX system was designed in Sweden as an addition to a standard SNCR process. The Mobotec system has been installed on a num ber of fu ll-scale utility boilers lo cated in the US, North Carolina where rem oval efficiencies as high as 70-80% have been achieved. Most Mobotec experience to date is on units firing east ern bitum i nous coal with high initial NO x 

### levels.

Mitsui Babco ck NOxStar System
The NOxStar process is a post-com bustion process th at continuously injects co ntrolled quantities of an ammonia-based reagent with relatively m i nut e am ounts of hydrocarbon (t ypically natural gas or propane) into the superheater/rehea ter pass of an operating boiler. The injection g r id c o m p rises a
perm anent array of feed lances attached to the ad jacen t heat transfer asse mblies in th e upper furn ace pass. The lance grid is divided into num e rous discrete zones bot h in width and height in the convective gas pass. This arrangem ent optim izes reagent distribution thro ughout the relatively high
tem p erature NO x 

### -bearing flue gas mass. At these existi ng elevated tem p e r atures, the hydrocarbon auto-ignites to form a pl asm a of free radicals, wh ich auto catalyses th e r eaction of ammonia and NO x 

### to form har m less nitrogen (N 2 

### ) and water vapo r (H 2 

### O).

The NOxStar process has dem onstrated rem oval efficiencies of 60-68% NO x 

### at inle t NO x 

### levels of between 0.25 to 0.4 lb/MMBtu at T V A' s Colbert 4 station.

In conjunction with other in-fur nace technologies such as low NO x 

### burners or a single layer of catalyst installed in the existing ductwork, NO x 

### reduction over 75% is co nsidered ach ievable with NOxStar plus system

.
NOxStarTM Process

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### Modification of Existing Foster Wheeler Low NO x 

### Burners on Units 5 & 6

Retrof itting the boiler un its with Fos t er W h eeler low NO x 

### bur ners could reduce NO x 

### levels. The low NO x 

### burners redistribute com bustion air to the bu rners to ach ieve low NO x 

### levels. Installation of these burn e rs in the arch fired boilers, would involve furnace and furnace front m odifications.

The arch-fired boiler arrangem e nt is fairly rare am ong today's utility boilers. Nevertheless, Foster Wheeler ind i cated they h a ve successfully m a de NO x 

### -reduction m odifications arch-fired boilers.

However, in f u rther dis c ussions with Foster W h eeler it was d e term ined th at the i r exp e rienc e was n o t with PRB Coal. Foster Wheeler was not forthcom ing concerning the app licab ility of this app r oac h to PRB.

Ultim ately it was conclu ded that thes e burners alone would not reduc e th e NO x 

### level to the pe rm it lim its.

3.2 Post Combu s tion NO x 

### Control Technology – Selected Catalytic Reduction (SCR)

Selective Ca taly tic Redu ction (SCR) utilizes a ni trogen-based reducing agen t, such as urea or ammonia to reduce flue gas NO x 

### to molecular n i trogen (N 2 

### ) and water vapor (H 2 

### O). The SCR
process em ploys a m e ta-based cataly st with activ at ed s ites to incre a se th e rate of the re duction reaction, res u lting in a higher NO x 

### removal efficiency within a lower and broader temperature window that that possible for non cat alytic processes. The dom i nant reduction reactions involved in the SCR process are described by the following equations:

4NO + 4NH 3 

### + O 2 

### Æ 4N 2 

### + 6H 2 

### O

2NO 2 

### + 4NH 3 

### + O 2 

### Æ 3N 2 

### + 6H 2 

### O

These NO x 

### reduction reactions occur as the flue gas pa sses through the catalyst cham ber. Reagent is injected into the flue gas downs tream of the econom i zer through an injection grid m o unted in the ductwork. The reagent is typically diluted with compressed air or st eam to aid in injection, and is injected at a sufficient distance ups tream of the cat aly s t cham ber to a llow f o r adequate m i xing of the reagent and flue gas. The hot flue gas and r eag en t then flow into the c a talyst where N O x 

### in the f l u e gas chem ically reduces into nitrogen and water. T h e nitrogen, water, and othe r flue gas constituents flow out of the SCR reactor.

The SCR pr ocess has demonstrated rem oval efficiencies of 70-90% NO x 

### . For this study, a 29% by weight aque ous ammonia is selected as the NO x 

### control reagent.

SCR can be located in th ree places. T h ese are:

• Hot Side SCR, with the reacto rloca ted between th e econom izer and air preheater. In this configuration the SCR is located upstream of the existing cold side ESP and is subject to a high fly ash loading. This is the most commonly used configuration in the industry.

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### Hot Side SCR

• Cold Side SCR, with the reac tor lo ca te d between the existing induced draft fan and the booster fan for the FGD system. In this configuration the SCR is located downstream of the existing cold si de ESP and is subjected to a low fly ash loading at norm a l operation. This c onfiguration requires a gas-gas heat exchanger and duct burners or steam coil heaters to bring the flue gas
tem p erature to reaction tem p erature. Steam reheat is likely the lower cos t option.

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### Cold Side SCR

• Tail End SCR, with the reacto r loca ted downstream of a FGD system and upstream of a stack. In this configurat ion since the SCR is located downstream of the existing cold side ESP and the F GD system, it is sub j e c ted to a ver y low fly ash and SO 2 

### loading. It also requires a gas-gas heat exchanger and duct burners or steam coil heaters to bring the flue gas tem p erature to reaction
tem p erature. The natural ga s or steam usage is h i g h er than the cold sid e SCR due to the lo wer FGD system exit ga s tem p er ature. The expected catalyst life is longer because som e of the catalyst poison chem icals would be rem oved in the FGD syste m

.

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### 3.3 SO 2 

### Control Technologies
Limestone Forced Oxidation System (LSFO) LSFO Process Description
In the LSFO process, hot flue gas exiting the ESP enters an ab sorber wher e it is contac ted with a dilute calcium carbonate and calcium sulfate sl urry (typically 15%-20% by weight suspended solids). The dissolved SO 2 

### reacts with the calcium carbonate in the limestone particles and the slurry d r ain s into th e abs o rber reactio n tank (integ ral with the absorber ). Lim e stone with f o rced oxidation FGD is a m o dification of a trad ition a l we t lim estone FGD process and inv o lves con tin uous sparging of air into th e reaction tank (sparg ing air is provid e d by de dicated air com p res s ors). This process alleviates problem s such as gypsum scali ng and dewatering difficult ies that plagued early natural oxidation, wet lim e stone processes. LS FO offers the advantage of controlled oxidation of reaction products and potentially scale-free operation of the wet scr ubber. LSFO produces a salable byproduct in the form of commercia l-grade gypsum that can be used for wallboard m a nufacturing or other industrial applications.
LSFO Process

The chem istry for the L SFO process begins with lim estone (CaCO 3 

### ) reagent, being f e d to the spray tower absorber, in an aqueous slurry at a m o lar feed rate of 1.02-1.03 m o les of CaCO 3 

### /m ole of SO 2


### rem oved, when producing wallboard quali ty gypsum . The m a jor product of SO 2 

### reaction with

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### lim estone is the form ation of hydrated calcium sulfite (CaSO 3 

### • 1/2H 2 

### O(s)) acco rding to the f

o llowing re action :

CaCO 3 

### (s) + SO 2 

### (g) + 1/2H 2 

### O Æ CaSO 3 

### • 1/2H 2 

### O(s) + CO 2 

### The sulfite is oxidized by the injection of air into the bottom of the absorb er reaction tank, and then hydrated to form calcium sulfate (CaSO4 • 2H2O) through the following reaction:

CaSO 3 

### • 1/2H 2 

### O(s) + 1/2O 2 

### + 3/2H 2 

### O Æ CaSO 4 

### • 2H 2 

### O

The absorber m a y be an open spray tower, a spra y tower with a gas/liquid contact tray, a fountain type spray, or a jet bubble r reactor. The contact tray prom otes additional rem oval efficiency but results in ad dition a l flue gas pressu re drop.

The LSFO process requires m a keup water to repl ace the losses that o ccur through evaporation, in liquor entrained in the byproduct solids, and due to blowdown stream s used to control dissolved solids and fines. This makeup water can be suppl ied from any source that is not saturated with respect to any of the dissolved so lids and contains a re latively low concentration of suspended solids. However, the m i st elim inator wash stream , which se rves as a relatively large portion of the scrubber

m a keup water, m u st be potable water in order to m a intain scale-free operation.

The LSFO process is cap able of rem o ving m o re than 95% of the SO 2 

### pres ent in the in let f l ue gas. Up to 98% SO 2 

### rem oval effi ciency is achievable.

The LSFO process requires lim e stone as its reag ent. The followi ng table shows a typical lim estone specification

. Limestone Properties

CaCO 3 , wt % dr

y > 95 CaCO 3 , wt % (a

vailable) dry 94 MgCO 3 , wt % dr

y 0.5 – 3 Total Inerts, wt %

dry 3 –7 Moisture, wt % 7 Particle Size (inch) (no mo re than 50 %

< 6 mesh) ≤ 3⁄4" x 0" Bulk Densit y, lb m/ft 3 100 Reactivity Test Per EPRI Metho d

or equal Work Index, kW h/ short ton 13


### LSFO Byproduct Handling

The SO 2 

### rea c tion with c a lcium carb onate in itially f o rm s calc i um sulf ite, which is sub s equently oxidized to calcium sulfate (gypsum ) in the abso rber reaction tank. The form ation of gypsum crystals in th e slurry help s to reduce s caling po ten tial by providing suspen ded crystal s u rface for crystal grow th and reducing the calcium sulfate satu ra tion lev e l in the slu r ry. A certain level of sulfate super saturation is re quired for gypsum for m ation.

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### The gypsum slurry rem o ved from the absorber reaction tank is part ially dewatered using hydroclones

. No additiv es are required to accom p lish th is s e paration sin ce gypsum c r ystals from the LSFO process tend to be relatively large, dense crystals that do not retain water. The hydroclone overflow is returned to th e sc rubber reaction tank. The hydroclone underflow is directed to a dewater i ng f acility, whic h uses either rotary d r um or belt f ilte r s . The cake com i ng off the belt f i lte r is typically 90% gypsum solids and 10% water. If the gypsum is to be sold for industrial use, a washing seq u ence is included in th e vacuum filter design, to reduce chlo ride conten t and elim inate
contam ination. Only water low in dissolved and su spended solids should be used for washing the
gypsum filter cake. The cake wash water is usua lly heated to prom ote drying to less th an 10% moisture.

The gypsum from the vacuum filter is transferred by belt con v eyor to a s t orage building, when it is to be sold for wallboard production. The gypsum is offloaded from the storage area by conveyor to barge, trucks, or railcars for sh ipm e nt to th e wallboard plan t.
LSFO Purge Wastewater Treatment
Blowdown of a portion of the proc ess water returned from the gyps um de watering/washing process is necessary to control th e concentr ations of disso lved solids in the scrubb er liquor as it concen trates due to the continuous recycle of sc rubber slurry and evaporation of water into the flue gas. The blowdown stream is used prim arily to control ch loride levels in the ab sorber reaction tank and recycle system . A typical equilib rium chloride level is 15,000 ppm

. The blowdown stream m a y also be used to purge fines, which tend to blind filt er cloths, leading to di fficulties in dewatering.

The quality of the wastewater purge stream from the FGD pro cess depends upon the sources of

m a keup water, the coal com position, and the bypr oduct specifications. Contam inants that m a y require rem oval could include trace heavy m e tals a nd chlorides. Multi-s t age treatm ent system s are typically used, consisting of pr ecipitation, flocculation, and dewateri ng equipm ent to address Hg, Fe, Cd, and other contam inants. Sodium hydroxide or lim e is added to increase the pH to approxim a tely 9 where m a ny m e tals will tend to pr ecipitate out of the solution. S odium sulfide is then added to precip itate addition a l m e tals to le v e ls of less than 0.1 ppb. Ferric ch loride is then added to rem ove excess sulfides and to produce large flocs of solids that are easily dewatered. Chlorides can be

rem oved by a variety of m e thods including evaporat ion or treatm e nt with activated carbon, but is usually not treated. The solids ge nerated by these treatm ent system s have to be disposed in an environm entally acceptable m a nner. The liquid st ream can be used for coal pile wetting, ash sluicing, and/or com b ined with th e plant cooling water discharge.
LSFO Limestone Reagent

Lim e stone from the bulk storage area is transferre d to a local storage area by trucks. T h e reclaim system includes a vibrating feeder and conveyor syst em to transfer lim estone to day bins. Lim e stone day bins and f eeders sup p ly lim eston e to ball m ills. The ball m ills grind the lim estone to 95 perc e n t less than 325 m e sh and use a wet recycle classificat ion loop to ensure proper size distribution to the process. This particle size pr oduces a large surface area for ga s contact w ithout excessive power

consum ption by the ball m ill. The 3 0 -35 perc ent solids s l ur r y f r om the ball m ill sys t e m is stored in lim estone slurry tank s pr ior to tran sf er to th e abso rbers.

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### Lime Spray Drying System (LSD) LSD Process Description

The lim e spray drying process is a sem i -dry FGD sy stem that produces a dry m i xture of fly ash and reaction products. In the Lim e Spra y Dryer process, the hot flue gas ex iting the pre c ipita tors en te rs a spray dryer vessel. W ithin the ve ss el, an atom i zed slurry of lim e and recycled so lid s contacts th e flue gas stream . The sulfur oxi des in the f l ue ga s reac t with th e lim e and fly ash alkali to form calcium salts. The water entering with the slurry vaporizes, lowering the tem p erature and rais ing the moisture content of the scrubbed ga s. In som e spray dryer designs, the scrubbed gas leaves from the side of the vessel, and a portion of the dried reaction products and fly ash drop out in the conical bottom

. The spray dryer outlet temperature is typically controlled within 1-2 ° F of the operating set point (norm a lly 35 ° F above the gas saturation tem p erature). If the coal sulfur conten t varies over a wide range in a short period of tim e, there m i ght be a tendency to operate outside of the norm a l outlet
tem p erature range. A closer approach to the sa tu ration tem p erature allows the LSD system to achieve higher rem oval efficiency for a short pe riod, but at the sam e tim e risks the buildup of wet solids on internal surfac es with the resultant potential for corrosion.

A particulate control device is requ ired downstream of the spray drye r. A fabric filter downstream of the LSD vessels removes the dr y solid reaction products, unreacted reagent, and fly ash before the scrubbed gas is released to the atm o s phere. The fa bric filter bags collect a layer of solids on their surfaces between clean ings, and the move m e nt of the flue gas through th is layer enhances the g a ssolid contact. A portion of the co llected reaction product and fly ash so lids is recycled to the slurry feed system . The rem a ining solid s are tr ansported to a landfill for disposal.

The following chem ical reactions define how the sulf ur dioxide is rem oved from the flue gas in the lim e spray drying process:

Raw lim e is slaked with an excess of water to form a calcium hydroxide slurry:

CaO + H 2 

### O Æ Ca(OH) 2 

### The sulfur oxides in the flue gas are absorbed in to the slu rry and reac t to f o rm the salt products:
Ca(OH) 2 

### + SO 2 

### Æ CaSO 3 

### • 1/2H 2 

### O + 1/2H 2 

### O Ca(OH) 2 

### + SO 3 

### + H 2 

### O Æ CaSO 4 

### • 2H 2 

### O A fraction of the sulfite product m a y also be ox idized to the sulfate form by reaction with oxygen in the flue gas:
Ca(OH) 2 

### + SO 2 

### + 1/2O 2 

### + H 2 

### O Æ CaSO 4 

### • 2H 2 

### O Any HCl in the flue gas, pres ent b ecause of the ch lorid e content of the fired coal, also absorbs in to the slu rry an d r eacts with the slaked lim e by: Ca(OH) 2 

### + 2HCl Æ CaCl 2 

### + 2H 2 

### O

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### LSD Process

The m a jority of the water evapo r ate s in the sp ra y dryer, leaving dry particles com posed of the reaction products, unreacted absorbent, and fly ash. In the particulate control device, the rem a ining SO 2 

### continues to react w ith the residual lim e in the collected solids, although at a m u ch slower rate. As m u ch as 25% of the total SO 2 

### removal can occur in the baghouse. In addition, the LSD process is highly effective at contro lling sulfur trioxide, which condenses with water vapor to form sulfuric acid. Over 90% of the sulfur trioxi de that is form e d during combusti on is absorbed in the LSD vessel and FF. This elim inates the potential for acid-rela ted problems such as plum e opacity due to acid

m i st or sulfuric acid corrosion in the downstr eam ductwork and particul ate collection system

. However, if the outlet gas tem p erature drops too low, then water condensation can occur on downstream surfaces. T h e water d r o p lets can abs o rb addition a l SO 2 

### producing sulfurous acid, increasing the potential for corrosio n, and can fo rm a m ud t h at can plug the filter bags.
LSD Removal Capabilities and Other P e rformance Parameters

The Lim e Based Sem i -Dry system (LSD) can m eet the specified 0.07 lb/MMBtu S O x 

### em ission and 95% rem oval efficiency for the design coal. In order to achieve 95% SO 2 

### rem oval, plant operators must closely watch the L S D system operation and ad just the p r ocess con t r o l param e ter s f r equently. Any variation of boiler op erations can cause th e SO 2 

### e m ission to exceed the lim its. Based on industrial experience, a 92-93% SO 2 

### rem oval can be consistently achieved. The LSD s y stem for each boiler will be com p rised of on e spray dry e r, followed with one fabric filter m odule.
LSD Reag ent The LSD process requires pebble lim e as its reag ent. The following table shows a typical lim e specification

.

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### Pebble Lime Property

CaO, wt % (Total) > 95 CaO, wt % (available for reaction) 90 or greater MgO, wt % 2 %

max Inerts, wt % 5 M

o

i s

t u r

e N e g l i g i b l e Particle Size (inch) 1⁄4" to 3/8" Bulk Densit y, lb m/ft 3 55 – 60 Reactivity Slaking rate test – Achieve 40 ° C temp rise in 3 min. or less



### Fresh slak in g water is in troduced wh ich hydrates th e pebble lim e . A ball m ill slaker p u lverizes the iner t m a teria l and m a intains the iner ts with the rea g ent slurry. If a de tention or paste slaker is used, the grits are rem oved at the slaker for se parate disposal. The slaked lim e , Ca(OH) 2 

### , flows to an agitated lime slurry feed tank, and this slurry is then pum ped to th e lim e spray dryer rotary atom izer
LSD Waste/Byproduct Handling
The spray dryer system produces a dry solid produc t consisting of calcium sulfite/sulfate, unused hydrated lim e, and fly ash. These dry solid produ cts can be handled by conventional dry fly ash handling system s. A por tion of the collected reacti on product and fly ash solid s is recy cled to the slurry feed system and the rem a ining solids are sent via the dry solids conveying system s to a storage silo. From the silo they ar e tr ucked to a la ndf ill f o r dis posal.
Circulating Fluidized Bed (CFB) Absorption System CFB Process Description
The Circulating Fluid Bed Scrubber (CFB) proce ss is a dry scrubbing tech nology. The process is totally dry, m eaning it not only produces a dry, f r ee flowing disposal product but also introduces the lim e reagent as a dry, free flowing powder.

In a Circulating Fluid Bed (CFB) process, the fl ue gas enters the bottom of the fluidized bed reactor(s). As the flue gas ente rs th e venturi-sh aped entrance to each reactor, it is m i xed with hydrated lim e reagent and recycled fly ash and reaction product solids . Water is injected into the reactor to hum i dify the fl ue gas and assist in SO 2 

### rem oval.

The CFB reactor h a s a tall cy lind r ical configuration to allow adequate tim e for the m i xing of the SO 2 

### laden gas with the reagent to com p lete the reac tion. Calcium salts are form ed when the hydrated lim e and fly ash react with the su lfur oxides in the flue gas.

The spent so lids and fly ash are car ried out of the top of the react or and captured downstream by a fabric filter or an ESP, one for each CFB Reactor. A portion of these combined solids is recy cled to the fluid bed absorber v i a air s lid es. The rem a ining m a terial is transported to a disposal solids silo. The fly ash and reaction products are drawn from the silo and condition ed in a pug m ill(s) for disposal to landf ill.

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### CFB Proces s

The Circulating Fluid Bed process chem ical reac tions are sim ilar to that of the Spray D r yer Absorber, as shown below:

Lim e Hydra tion: CaO + H 2 

### O ⇒ Ca(OH) 2 

### SO 2 

### Reaction: Ca(OH) 2 

### + SO 2 

### ⇒ CaS O 3 

### .1/2H 2 

### O + 1⁄2 H 2 

### O

SO 3 

### Reaction: Ca(OH) 2 

### + SO 3 

### + H 2 

### O ⇒ CaSO 4 

### . 2H 2 

### O

Sulf ite Oxid ation : Ca(OH) 2 

### + SO 2 

### + H 2 

### O 1/2O 2 

### ⇒ CaSO 4 

### . 2H 2 

### O

HCl Reactio n: Ca(OH) 2 

### + HCl ⇒ CaCl 2 

### + 2H 2 

### O

Pebble lim e is transported pneum atically from the lim e stora g e silos to th e lim e day bin which f e e d s the dry lim e hydration plant. From the day bin, pebbl e lim e is charged into a lim e hydrating fluid bed reactor. The pebble lim e is hydrat ed by the injection of fresh wate r in the hydrating reactor in an

am ount proportional to the feed rate of the pebble lim e. Hydrating water consum ption is approxim a tely 150% of the stoichio m e tric require m e nt. The highly reactive hydrated lim e product is
pneum atically transported by one of two 100% capac ity hydrate transfer bl owers to four hydrated lim e surge bins, one for each CFB tower. A total of four CFB towers are provided, on e for each u n it. The hydrated lim e reagent is drawn from each hydrat ed lim e surge bin by a variable speed rotary feeder which transfers the hydrated lim e to an airslide which conve ys and feeds the hydrated lim e into th e asso ciated scrub b er tower.
The hydrated lim e feed rate through the variable sp eed rotary feeder and ai rslide into the CFB is adjusted based on a feed forward signal from the SO 2 

### inlet an d outle t m o nitors. Injection of water direc tly into the CFB rea c tor f u rth e r enhances S O 2 

### rem oval efficiency making 96% to 98% rem o val

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### efficiency feasible with this technology. However, since high rem oval effi ciencies of 96% to 98% have not been commercially dem onstrated in FG D system s s e rving large power plants, the evaluation of CFB technology in this study is based on 95% SO 2 

### rem oval. Furtherm ore, the stoich iom e tric ra tio, and the assoc i ated lim e consumption rate for SO 2 

### removal lev e ls g r eater th an 95% have not yet been accurately determ ined or dem onstrated.

The evaporation of water within th e CFB reactor results in d e creas ed flue gas tem p erature and increased hu m i dity. Desulfurized flu e gas exits the CFB reactors and is d r awn throug h either an electros tatic precip itator (ESP) or fabric filter, on e per CFB reacto r

. Fabric filters are assum e d for Oak Creek. Hydrated lim e and SO 2 

### reaction products are separated from the flue gas and collected with the fly ash in the new fabric filter hoppers. The fly ash and r eaction solids are discharged from the hoppers and split into two stream s. The first str eam is recycled via an airslide and fed back into the lower section of the associated C F B reactor. Th e second stream is discharged thro ugh an airlo c k hopper and transported by a pneum atic pressure c onveying system to a fly ash / reaction products storage silo. The fly ash and reac tion products are gravity dis c harged fro m the silo in to a pug m ill. The pug m i l l conditions and discharges the ash and reaction products into ash dum p trucks for transpo r ta tio n to the land f ill.

The flue gas exiting the f a bric filter is ducted to new booster fans, and then to the chimney.
CFB System Materials and othe r Mechanical Considerations

The CFB ve ssel and ductwork are ty pically constructed of carbon st eel because sulfuric acid is absorbed an d neutralized by the alk a line solid s present.
The CFB system includes the dry hydrati on plant upstream of the reactor vessels.

Evaluation of the CFB system includes a new fabric filter immediately down stream of the reacto r vessel to cap ture the re ac tion products, unreacted ab sorbent, and fly ash.

Evaluation o f the CFB system includes the cos t s a ssociated with installation and operation of new booster fans located immediately downstream of th e FF. The additional pressure provided by the new fans compensates for pressure losses due to the CFB' s, FF and ductwork.

3.4 Multi-Polluta nt (NO x 

### , SO 2 

### and Mercury) Control Tec hnology J-Power ReACT System Process Description

The ReACTTM technolo gy is a dry multi-po llutant c ontrol technology. It util izes a moving activated coke (AC) bed with ammonia inject ion to sim u ltaneously remove SO 2 

### , NO x 

### , and mercury from the flue gas. The ReACT system (process flow diagra m shown in Figure 3-1) consists of three m a jor process step s:

• SO 2 

### and Hg are rem oved by adsorption onto activated coke pellets in the adsorber m odules, while NO x 

### is rem o ved by reduction reactions

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### • SO 2 

### desorption and activated coke rege neration occurs in the regene rato r modules

• Sulfuric acid by-product producti on is in an acid plant.

ReACT Tech nology Process

NH 3



### Adsorption

Each adsorber m odule consists of a bed of ac tivated coke m oving slowly downward through each open cell at a constant rate. W h en the flue gas pa sses through the activated coke bed (horizontal gas flow), SO 2 

### is adsorbed onto the activated coke w h ere it reacts with oxygen and water in the flue gas to f o rm sulfuric a c id. T h e sulf uric a c id then r eacts with th e injected a mmonia to form a m m onium sulfate and b i sulfate salts accord ing to the following chem ical reactions :

Sulfuric Acid 4 2 2 2 2 1 2 

### SO H O H O SO → + +

Ammonia Salts 4 4 3 4 2 

### HSO NH NH SO H → + 

# ( ) 4 2 4 3 4 4 

### SO NH NH HSO NH → +

Activated co ke also work s as a NO X 

### reduction catalyst. NO X 

### in the flue gas is reduced to nitrogen and water w h en it reacts with amm o nia and oth e r species on the surface o f activated coke.

O H N O NH NO 2 2 3 2 2 4 1 3 

### + → + +

NO + NH x 

### O-AC → N 2 

### + H 2 

### O + OH- AC (where AC = Activated Coke)

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### AC fines are generated as the coke m oves through th e adsorb er cells and can be entrained in the flue gas. However, the adsorber does remove som e of these fines as well as a portion of the fly ash that enters with the incom i ng flue gas. The adsorber can achieve an expected net particu l ate rem oval of 70%.

As the activated coke trav els down the adsorber, it continuously adsorbs m e rcury, SO 2 

### and NO x 

### from the flue gas and gradually loses its adsorp tion capability. The ReACT system i s designed so that when th e activated coke is dis c h a rged from the adsorbe r , the spen t ac tiva t ed coke is satu ra ted with amm o nia sa lts and s u lf uric acid. The AC elevator then tr ansfers the s p ent coke from the adsorber m odules to a lock hopper before the coke is delivered to the rege nerator m o dules. J-Power has confirmed that the activated coke rem oves 90+% of the m e rcury contained in the inle t f l ue ga s.
Regenerator
To regain th e activated coke adso rption capability, the spen t activ ated coke needs to be reactivated in a regenerator vessel by indirect hot gas heating. The coke goes thr ough three stages of processing – preheating, regeneration and cooling – in the rege nerator m o dules to com p lete the regeneration cycle.

At the preh eating s t age, the spent ac tivated coke is heated indirectly to a p r eset tem p erature us ing th e hot air exiting from the coke cooling process. Th e heated activated coke then trav els d o wnward to the regeneration stage.

At the regeneration stage, the preheated activated coke tem p erature is raised further to 750-930 ° F. Ammonium sulfate and s u lfuric acid trapped on th e activated coke surface are th erm a lly decom posed to amm onia vapor, sulfur dioxide and wa ter vapor. Mercury is not released during the regeneration of the activ ated coke. The coke ha s a high cap acity for Hg adsorption, and will req u ire regeneration to rem ove the collected m e rcury ev ery 2-3 years depending u pon the concentration of

m e rcury in the fuel.

The gas stream generated in the regenerator m o dules is then di rected to a by-product recovery facility for further p r ocessing. A natural gas o r o il-fired furn ace equipp ed with a co mbustion air fan is used to generate the hot gas that is needed for the AC regeneration.

The regenerated activated coke m ove s into the co oling section at the bott om of the regenerator module where it is cooled indirectly by air. On ce cooled to a preset tem p erature, the AC is transferred to a discharge lock hopper.

From the lock hopper the cooled activated coke is se nt to a separator where cl assification air is used to separate the degraded fine m a terial from the c oke m eeting the desired size param e ters. The fine

m a terial en trained in the class i ficatio n air is sen t directly to a dust collecto r where th e fines and air
are sep a ra te d. The f i ne activ ated co ke can then be burned in the boiler o rsent to a la ndf ill f o r disposal. For this analysis, it was assu m e d that the fines would be landfilled.

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### Fresh activated coke is added to rep l ace the fines th at are lo st during th e regeneration process. Th e added fresh coke along with the rege nerated coke is then recycled b ack to the adsorber m odules via an AC supply elevator.
By-Product Recovery Facility to Prod uce Sulfuric Acid

The SO 2 

### -rich gases from the regenerator m u st first go through a cleaning pr ocess to remove the entrained du st and oth e r im purities th at m i ght degrad e th e quality of the su lfur ic acid p r oduct. Once cleaned, the SO 2 

### -rich gas stream is sent to an SO 2 

### to SO 3 

### converter.
Equipm ent used for washing the con centrated s t ream of SO 2 

### would normally consist of a wet scrubber, a cooler, a wet m i st precip itator, a drying tower and a blower. T h e wet scrubber is used to cool and remove the entrained dust and im purities. The gas cooler is used to reduce the water vapor in the SO 2 

### -rich gas. The m i st precipitator is used to rem ove fine acid m i st generated in the wet scrubber an d cooler. A drying towe r is used to rem ove additional water vapor from t h e by-produ ct gas stream

. After the washing and cleaning process, the cooled and cleaned SO 2 

### -rich gas is reheated before it is
sent to a con v erte r to co mplete the c a taly tic con v ersion of SO 2 

### to SO 3 

### . After the conversion, the SO 3 

### is absorb ed in a f i nal abs o rbing towe r to f o rm a 98% sulf uric acid so lutio n. Bef o re the SO 3 

### - free gas can be discharged to the atm o sphere or sent ba ck to the ReACT system , it passes th rou gh a m i st elim inator located a t the exit of the f i nal ab sorbing tower to rem ove any fine acid m i st entrained in the gas stream.

J-Power does not supply the by-produc t recovery facility. Suppliers such as Monsanto Enviro-Chem can provide sulfuric acid plants . For this study the by-product rec overy cost is factored from a previous Monsanto quote.

A Process Flow Diagram for a typical Monsanto E nviro-Chem H 2 

### SO 4 

### process is provided below:

Sulfuric Acid Plant Process

G a s H e a t i n g

S O 2 + 1⁄2 O 2 S O 3 A l l o y T r o u g h D i s t r i b u t o r s

G a s C ool i n g C a t a l y t i c C o n v ert er w i t h E n v i r o - C h e m C a t a l y s t Ga s He a t E x c h a n g e r In t e r p a s s A b s o r b i n g T o w e r w i t h Br i n k M i s t E l i m i n a t o r s F i n a l A b s o r b i n g T o w e r wi t h B r i n k M i s t E l i m i n a t o r s S t a c k B r i n k M i s t E lim i n a t o r SO 3 + H 2 O H 2 S O 4 P r i m a r y D y n a w ave R e v ers e J e t S cru b b e r G a s C ool i n g T o w e r W e t E l ect rost a t i c P reci p i t a t o r D r y i n g T o w er w i t h D e m i s t e r C o m p res s o r F i n a l D y n a w a v e R e v e r s e J e t S c r u b b e r

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### PowerSpan ECO System Process Description
The ECOTM process is designed fo r installation downstream of an exis ting particula t e c o llec tion device. The process utilizes a dielectric barrier di scharge reac tor to ox idiz e pollu tants in the f l ue g a s stream , followed by a wet amm onia s c rubber and wet ESP for rem oval of oxidized pollutants and byproducts. The technology produces a saleable amm onium sulfate/ammonium nitrate fertilizer byproduct. PowerSpan ECOTM Proce ss

Flue gas flo w s from the existing ESP or fabric fi lter into an electrocataly tic oxidation (ECO) reactor, where hydroxyl (OH) radicals and atom ic oxygen (O) are form ed by the reaction of high-energy electrons with water and oxygen m o l ecules.

O 2 

### + e- Æ O + O + eH 2 

### O + e- Æ OH + H + eO + H 2 

### O Æ 2OH

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### These rad i ca ls then reac t with pollu ta nts in th e f l ue gas, oxidizing m e rcury (Hg) to m e rcuric oxide (HgO), SO 2 

### to sulf uric a c id (H 2 

### SO 4 

### ), and NO x 

### to nitr ic ac id ( HNO 3 

### ). Approxim a tely 90% of NO in the flue gas is oxidized to NO 2 

### and HNO 3 

### at this stage. Less than 10% of SO 2 

### in the gas is ox id ized to f o rm SO 3 

### , which ultimately f o rm s sulf uric a c id

.
OH + SO 2 

### Æ HSO 3 

### HSO 3 

### + O 2 

### Æ HO 2 

### + SO 3 

### SO 3 

### + H 2 

### O Æ H 2 

### SO 4 

### NO + HO 2 

### Æ NO 2 

### + OH

O + NO Æ NO 2 

### OH + NO 2 

### Æ HNO 3 

### O + Hg Æ HgO

The oxidized flue gas is then se nt to a double loop ammonia scr ubber where the final products are

rem oved from the flue gas stream . In the upper lo op of the scrubber, ammonia is added to form ammonium sulfate and n itrate byp ro ducts by reaction with sulfuric and nitric acid. T h e lower loop of the scrubber cools and satura tes the flue gas and concentrat es the byproducts for removal. Oxidation a i r is added to the lower lo op to f u rthe r oxidize sulfites and nitrit es. Chem ical reactions that occur in the scrubber are:

H 2 

### SO 4 

### + 2NH 3 

### Æ (NH 4 

### ) 2 

### SO 4 

### HNO 3 

### + NH 3 

### Æ NH 4 

### NO 3 

### SO 2 

### + H 2 

### O Æ H 2 

### SO 3 

### H 2 

### SO 3 

### + 2NH 3 

### Æ (NH 4 

### ) 2 

### SO 3 

### H 2 

### SO 3 

### + (NH 4 

### ) 2 

### SO 3 

### Æ 2NH 4 

### HS O 3 

### (NH 4 

### ) 2 

### SO 3 

### + 1/2O 2 

### Æ (NH 4 

### ) 2 

### SO 4 

### NH 4 

### HS O 3 

### + 1/2O 2 

### Æ NH 4 

### HSO 4 

### NH 4 

### HS O 4 

### + NH 3 

### Æ (NH 4 

### ) 2 

### SO 4 

### NH 3 

### + HCl Æ NH 4 

### Cl

The flue gas then enters a m i st elim inator that removes entrained droplets from the gas prior to entering a w e t ESP (W ESP) located in the top po rtion of the scrubber. The W E SP collects acid aerosols, particulate m a tter, and m e rcuric oxide, while collecting and recy cling ex ces s ammonia as an aqueous solution.

The soluble ammonium sulfate and nitrate byproducts exit the scrubber in a bleed stream that is treated by filtration to remove ash and insolubl e m e tal com p ounds. The stream is then passed through an activated carbon absorption bed where m e rcury com pounds are absorbed onto the bed. The purified byproduct stream is then sent to a crys tallizer w h ere well-defined sulfate and nitrate

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### crystals are form ed by evaporation. The crystals are then dried and granulated to form a fertilizer byproduct that could be m a rketable depending on quality and location. At sites where the fertilizer byproduct could be sold, but where synthetic gypsum from a lim e or lim es tone process could not be sold due to the absence o f a m a rket within th e eco nom i c haul distan ce, the ECOTM process would avoid the landfill dispo s al cos t s th at typically account for a larg e portion of FGD system operating
costs.

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### 4.0 NO X



### CONTROL TECHNO LOGY EVAL UATION

A set of m a ndatory criteria was id en tified and used to evalu a te each NO x 

### control technology. Each NO x 

### control technology is evaluated and ranked f o r each criterion. The technology that has the highest overall raking is considered the m o st suitable control technology.

4.1 Evaluation Criteria

Each NO x 

### control techn o logy is ev aluated in five areas – tech nology, cons tructability, operating an d

m a intenance, commercial risk, and perform a nce m a rgin. Basing on the rating criteria, a rating is assigned to each area.

• Technology Rating: 0 to 5 (5 is proven, 1 is to be dem onstrated, 0 is not appropriate f o r the Oak Creek installation) Rating Criteria

– Comm ercially proven on a power genera ting facility of 250 MW or m o re for a period at least one y ear and cu rrently available

– Capable of achieving the required NO x 

### rem oval efficiency

– Com p atible with exis tin g boile r configuration and equipm ent

• Constructability Rating: 0 to 5 (5 is easy, 1 is difficult, 0 is extremely difficult) Rating Criteria

– Com p atible with availabl e space and plant location.

– Com p atible with exis tin g boile r configuration and equipm ent

• Operating and Maintenance Rating: 1 to 5 (5 is easy, 1 is difficult) Rating Criteria

– Ease of operation

– Ease of Equipm ent Maintenance

• Comm ercial Risk Rating: 0 to 5 (5 is low, 1 is high, 0 is extrem ely high) Rating Criteria

– Comm ercially proven

– Com p arable experience with the project design fuel

– Com p arable experience with project boiler capacity

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### – Availability of guarantees

• Perform a nce Margin Rating: 1 to 5 (5 is good, 1 is poor) Rating Criteria

– Margin to achieve high er then required NO X 

### rem o val efficiency

– Addition of perform a nce-enhanced chem icals is required.

– De m onstrated.

Note: Tota l Ranking is r a ted ze ro when a ny one of the criteria is rated zero.

4.2 Technology Evaluation Results of Selec tive Catalytic Reactor (SCR) System

Units 5 & 6

Cold side and tail end S CR can be installed at the South side of the pl ant for Units 5 and 6.

After a caref ul rev i ew of the site, it is concluded that at east side of the pla n t, the r e is insuf f i cient space between the Units 5 & 6 boilers, existing E SPs a nd Lake Mich igan for installatio n of hot side SCRs f o r Units 5 & 6

. Further, it is e x trem ely di fficult (without m a jor plant m odifications at high cost) to run the ductwork from the air preheater to the hot side SCR and back to the air preheater. For m o re de tailed inform ation, see Section 4.3. Ther efore, only cold side and tail end SCRs are considered as valid options for these units.

Table 4-2A below summ arizes the technology evaluation results of th e cold side and tail end SCR for Units 5 & 6.
Table 4-2A. Technology Evalua tion of SCR for Units 5&6

Cold Si de Tail End Rankin g (0 -5) T e

c

h n

o

l o

g

y 3 4 C o n

s

t r u

c

t a b

i l i t

y 5 5 Operating and M a intenance 3 3 Commercial Risk 4 5 Performance Ma rgin 5 5 Total 2 0 2 2 Ot

her Fac t ors Scaling Require d No No Can meet 0.07 lbs/MMBtu NO x Emission? Yes Yes Unconditional C o mmercial Guarantees Yes Yes

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### Units 7 & 8

Cold side and tail end S CR can be installed at the South side of plant for Units 7 and 8.

There is adequate space behind ex isting Boile r 7 to install a h o t side Unit 7 SCR. Rout ing the ductwork from Unit 7 econom izer outlet to the SCR a nd back to the air preheater can be done with

m i ni m a l plant m odifications. It is expected that relocation of som e of the existing ductwork would be needed.

The Unit 8 hot side SCR can be located directly a bove the existing workshop on the south side of the plant. Routing of the duct from Unit 8 econom izer outlet to the SCR and back to the air preheater would require relocating existing platform s, Unit 7 ESP control room and electrical cables and conduit, FD fan inlet ductwork, pipin g, wall penetration and siding repairs, etc. It is estim a ted that an additional 60 days down tim e over the norm a l outag e duration would be needed for the tie in. Outage rep l acem ent power costs have been included in the total ev aluated cost, but the additional outage duration does not appear to nega tiv ely im pact th e overall schedule.

Table 4-2B below summ arizes the technology evaluation results of th e hot side, cold side and tail end SCRs for Units 7 & 8.
Table 4-2B. Technology Evalua tion of SCR For Units 7&8

Hot Si de Cold Si de Tail End
Rankin g (0 -5)
T e

c

h n

o

l o

g

y 5 3 4 C o n

s

t r u

c

t a b

i l i t

y 1 5 5 Operating and M a intenance 2 3 3 Commercial Risk 3 4 5 Performance Ma rgin 5 5 5 Total 1 6 2 0 2 2

Ot

her Fac t ors Scaling Require d No No No Can meet 0.07 lbs/MMBtu NO x Emission? Yes Yes Yes Unconditional C o mmercial Guarantees Yes Yes Yes



### 4.3 Elimination of Hot Side S CRs use on Units 5 & 6

Hot side SCRs for Units 5 and 6 would be norm a lly located behind the un its, between the boiler buildings and Lake Michigan. Ductwork would need to be run from the ou tle t of the existing boiler

econom izers inside the station building to the SC R in let, and then from the SCR outlet back into the station building to the ex isting air heaters.

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### No two SCR insta lla tions are a lik e, because of different station configurations. Retrofit SCR insta lla tions typica lly a r e reasonab l y difficult, because the plants we re not originally designed with sufficient ex tra space to accomm odat e the new eq ui pm ent. Measures requ ired for an industrytypica l SCR retrof it inc l u d e loca ting the SCR on new steel, reinforcing som e existing building support s t eel to accep t ad dition a l weight and load ing, and relo cating som e existing equ i pm ent to perm it routing of ductwork.

For Oak Creek Units 5 and 6 however, installing SCRs and their associated ductwork would be substantially m o re difficu lt than an "industry typical" installati on. The prim ary reason is that the units have already been retrofitte d with additional em ission control e quip m ent, specifically the larger precip ita tors . W h en the large r pre c ip ita tors we re added new ductwork wa s required, and the space that would otherwise have been available for th e SCR ductwork was consum ed. This is further

com p licated by the coal conveying system that is al so located inside the pl ant in this area. In addition, the existing econom i zer design does not perm it suffi cient space between the econom izers and air heaters to connect the SCR ductwork. Cons equently a workable physical arrangem e nt for SCRs and their associated ductwork on these units could not be identified.

To install S CRs would require extraordinary m easures that would inclu d e, as a m i nimum :

• De m o lishing the coal conveyors and associ ated equipm ent inside the plant and installing new conveyors in a location not yet determ ined. This would involve substantial modifications to the boiler building itself and its structural support steel.

• The precipitators and their ductwork w ould have to be reconfigured and possibly m oved to prov ide space for the SCR ductwork.

• The existing econom izers would have to be replaced with econom i zers of a different physical design, which would likely have an im pact on the boilers' therm a l perform a nce.
These are not the type of modifications that are encountered in an "industry-typical" SCR installation. Due to the unusual ex tent of required m odifications, th eir expense, and the substantial outage tim e s they would require fo r installation, hot-side SCRs are not considered practical for O a k Creek Units 5 and 6. The estim a ted outage ti m e exceeds 24 months, which would entail a replacem ent power cost in excess of $200 m illio n.

4.4 Cold-Side and Tail End SCR Industry Experience
Most experience with co ld-sid e and tail-end SCR is in Europe. Babcock Power, Alstom Power and Babcock & W ilcox were contacte d and requested to subm it thei r co ld-s id e and ta il- en d SCR reference list. Babcock Power and Alst om responded to the request, B & W did not.

Based on the received infor m ation, th e bulk of the European installati ons are the cold-side or tail-end configuration. Babcock Power' s re ference lis t in dicates that they have supplied tail-end SCR for twenty (20) power plants with a total of 4,550 MW Worldwide, prim arily in Europe. Many of those

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### designs were driven by specific s ite space cons traint s. Out of the twenty installations, seven plan ts have the tail end SCR located downstream of either a wet or dry FGD system

.
Alstom Power has supplied twenty (20) tail end S CRs in Europe. These plants are designed to burn waste or sludge.

In the USA there is only one known cold-side SCR installation at PSE&G Mercer Station. The coldside SCR at Mercer station is loc a ted downstrea m of an existi ng ESP and ID fan. A future FGD system is planned, whic h will be do wnstream of the SCR.

Based on the feedback from Babcock Power, Alst omPower and PSE&G Mercer station, the coldside and tail-end SCRs have all m e t the perfor m a nce requirem ents as originally designed.

Babcock Power and Alstom Power cold side a nd tail-end SC R reference lists are included as Appendix 8 in this report.

4.5 Technology Evaluation Results of Mobotec ROFA/ROTAMIX System
The Mobotec ROFA/ROTAMIX process will not work for Units 5 & 6. Mobotec' s process creates a rotational op posed fired air (ROF A) condition in the upper fu rnace.

Units 5 & 6 are arch-fired. The design of the units requires the use of high excess air to control
steam tem p e r ature. Stud y indicates that atte m p eration cannot be accom p lished by a means other than high excess air, so burner air cannot be dive rted to the upper furnace. Therefore, the Mobotec ROFA/ROTAMIX is not a feasible technology and is given a perfor m a nce m a rgin ranking of zero.

Units 7 & 8 are co rner-fired boilers . There is no restriction in the furnace to prevent th e introductio n of rotational opposed fired air. Mobotec RO FA/ROTAMIX m a y be used on Units 7 & 8.

Mobotec' s ROFA/ROTAMIX system has dem ons tr ated that it can rem ove 50 to 70% NO x 

### for a Tfired or wall fired boile r which normally has a ba seline or uncontrolled N O x 

### level of 0.35 lb/MMB tu or higher. Mobotec has not dem onstrated that th e ROFA/ROTAMIX system can achieve the same NO x 

### rem ova l for boilers like Oak Creek Units 7 & 8 that have a baseline NO x 

### level in the 0.12 to 0.15 lbs/MMBtu. Therefore, it is given a perform a nce m a rgin ranking of 1.
Summary:
The performance m a rgin issues put the Mobot ec system in a high t echnology risk category.

Table 4-5 below summarizes the overall evalua tion results of the Mobotec ROFA/ROTAMIX system

.

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### Table 4-5. Technology Evaluation of Mobotec ROFA/ROTAMIX System

Units 5 & 6 Units 7 & 8
Rankin g (0 -5)
T e

c

h n

o

l o

g

y 3 3 C o n

s

t r u

c

t a b

i l i t

y 3 3 Operating and M a intenance 4 4 Commercial Risk 0 2 Performance Ma rgin 0 1 Total 0 1 3

Other Factors Scaling Require d Yes Yes Can meet 0.07 lbs/MMBtu NO x Emission? No Unproven Unconditional C o mmercial Guarantees No Possib l y



### 4.6 Technology Evaluation Results of Mitsui Babcock NOxStar System
Mitsui Babcock offers the NOxStar pr ocess with and without in-duct SCR.

Only lim ited inf o rm ation was rece ive d f r om Mitsui-Babcock. However, investig ation indica ted th at Mitsui-Babcock has not dem onstrat e d perf orm a nce at low inlet NO x 

### levels like those at Oak Creek, so expected results are difficult to predict. In addition, congestion in th e roof and penthouse areas will hind er the use of Mitsui' s standard concen tric lance d e sign.

Mitsui Babcock stated that with som e design chan ges and/or enhancem ents to the NOxStar system

, or com b ining it with o t h e r NO x 

### reduction technology, W e Energies could possibly m e et its overall objectives. Mitsui Babcock proposed a phased appro ach to dem onstrate NOxSt ar technically at Oak Creek 5 & 6, and was not willing to offer perform a nce guarantees.

Mitsu i -Babcock provided a ROM estim ate for the NOxSt ar System with an in-duct SCR. However, this conf igu r ation is not consider ed f easib le due to lack of ductwork space at Oak Creek for installation of an in-duct SCR.

4.7 Summary of NO x 

### Control Technology Screening Results

SCR Techn o logy – The SCR process exhibits a higher eval uated ranking and has greater operational flexibility in term s of fuel flexibility. Due to layo ut issues hot side SCR cannot be retrofitted for Units 5 & 6, but can be considered for Units 7 & 8. The site layout pe rm its cold side or tail end SC R insta lla tion on the sout h side of plant.

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### NOxStar Technology – Was elim inated from further evaluati on due to the technical risk associated with its u s e.

Mobotec R O FA/ROTAMIX Technology – Furn ace type and geom etry precludes the application of Mobotec R O FA/ROTAMIX technology for Units 5 & 6. This technology was considered for Units 7 & 8, but was ultim ately d i scard e d due to unproven perform a nc e under con d itions sim ilar to Oak Creek.

4.8 Cost Compa r ison of NO x 

### Control Technology Options

The costs of the tec hnica lly f easib le NO x 

### control options are com p ared in the tables below:

Table 4.8A Cost S u mmary for Tail -End SCRs (Cos t in Millions)

Unit 7 & 8 Unit 5 & 6 I n c r e m e n t a l T o t a l Capital ($2006) $95.6 $83.0 $178.6

First Year O&M Steam $1.9 $1.9 O t

h

e r $ 3

. 1 $ 2

. 9 T o

t a l $ 5

. 0 $ 4

. 8 $ 9

. 8

Levelized O&M Steam $2.6 $2.3 O t

h

e r $ 4

. 4 $ 3

. 6 T o

t a l $ 7

. 0 $ 5

. 9 $ 1 2

. 9

Capitalized O&M Steam $25.2 $22.1 O t

h

e r $ 4

2

. 7 $ 3

5

. 1 T o

t a l $ 6

7

. 9 $ 5

7

. 2 $ 1 2

5

. 1

Total E v a l u a t

e

d C o s

t $ 1 6

3

. 5 $ 1 4

0

. 2 $ 3

0

3

. 7

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Table 4.8B Cost S u mmary for Cold-Side S CRs (Cos t in Millions)

Unit 7 & 8 Unit 5 & 6 I n c r e m e n t a l T o t a l Capital ($2006) $101.5 $89.0 $190.5

First Year O&M Steam $1.7 $1.7 O t

h

e r $ 6

. 1 $ 5

. 5 T o

t a l $ 7

. 8 $ 7

. 2 $ 1 5

. 0

Levelized O&M Steam $2.4 $2.1 O t

h

e r $ 8

. 5 $ 6

. 8 T o

t a l $ 1 0

. 9 $ 8

. 9 $ 1 9

. 8

Capitalized O&M Steam $23.1 $20.2 O t

h

e r $ 8

2

. 6 $ 6

5

. 9 T o

t a l $ 1 0

5

. 7 $ 8

6

. 1 $ 1 9

1

. 8

Total E v a l u a t

e

d C o s

t $ 2

0

7

. 2 $ 1 7

5

. 1 $ 3

8

2

. 3

Table 4.8C Cost S u mmary for Cold-Side S CRs (Uni ts 5 & 6) and Hot Side SCRs (U nits 7 & 8) (Cos t in Millions)

Unit 7 & 8 Unit 5 & 6 Incremental To tal Capital ($2006) $104.4 $89.0 $193.4

First Year O&M Steam $0.1 $1.7 O t

h

e r $ 6

. 1 $ 5

. 5 T o

t a l $ 6

. 2 $ 7

. 2 $ 1 3

. 4

Levelized O&M Steam $0.2 $2.1 O t

h

e r $ 8

. 6 $ 6

. 8 T o

t a l $ 8

. 8 $ 8

. 9 $ 1 7

. 7

Capitalized O&M Steam $1.9 $20.2 O t

h

e r $ 8

3

. 1 $ 6

5

. 9 T o

t a l $ 8

5

. 0 $ 8

6

. 1 $ 1 7 1

. 1

Total Evaluated Cost * $189.4 $175.1 $364.5 Note (*) Including $18M power p enalty

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Table 4.8D Cost S u m m

ary for Tail -En d SC Rs (U nits 5 & 6) and H o t Si de S CRs ( U ni ts 7 & 8) (Cos t in Millions)

Unit 7 & 8 Unit 5 & 6 I n c r e m e n t a l T o t a l Capital ($2006) $104.4 $83.1 $187.5

First Year O&M Steam $0.1 $1.9 O t

h

e r $ 6

. 2 $ 2

. 9 T o

t a l $ 6

. 3 $ 4

. 8 $ 1 1

. 1

Levelized O&M Steam $0.2 $2.3 O t

h

e r $ 8

. 7 $ 3

. 6 T o

t a l $ 8

. 9 $ 5

. 9 $ 1 4

. 8

Capitalized O&M Steam $1.9 $22.3 O t

h

e r $ 8

4

. 4 $ 3

4

. 8 T o

t a l $ 8

6

. 3 $ 5

7

. 1 $ 1 4

3

. 4

Total Evaluated Cost (*) $190.7 $140.2 $330.9 Note (*) Including $18M power p enalty

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### 5.0 SO 2 

### CONTROL TECHNO LOGY EVAL UATION

A set of m a ndatory criteria was id en tified and used to evalu a te each SO 2 

### control technology. A control technology that has the highest overall raking is cons idered the most suitable.

5.1 Evaluation Criteria

Each SO 2 

### control techno logy is evalu a ted in five areas – tech nology, cons tructability, operating an d

m a intenance, commercial risk, and perform a nce m a rgin.

• Technology Rating: 0 to 5 (5 is proven, 1 is to be dem onstrated, 0 is not suitable for the Oak Creek a pplica tion ) Rating Crite r ia

– Comm ercially proven on a power genera ting facility of 250 MW or m o re for a period at least one-year and currently available

– Capable of achieving the required SO 2 

### rem oval efficiency

– Produces an acceptable waste produ ct for dispos al, if applicable.

– Com p atible with availab l e space, reag ent suitability/availability and plan t location

– A stable lon g -term m a rket exists for the by-product

• Constructability Rating: 0 to 5 (5 is easy, 1 is difficult, 0 is extremely difficult) Rating Crite r ia

– Com p atible with availabl e space and plant location.

– Com p atible with exis tin g boile r configuration and equipm ent

• Operating and Maintenance Rating: 1 to 5 (5 is easy, 1 is difficult) Rating Crite r ia

– Ease of operation

– Ease of Equipm ent Maintenance

• Comm ercial Risk Rating: 0 to 5 (5 is low, 1 is high, 0 is extrem ely high) Rating Crite r ia

– Comm ercially proven

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### – Com p arable experience with the project design fuel

– Com p arable experience with project boiler capacity

– Availability of guarantees

• Perform a nce Margin Rating: 1 to 5 (5 is good, 1 is poor) Rating Crite r ia

– Margin to achieve high er then required NO X 

### rem o val efficiency

– Addition of perform a nce-enhanced chem icals is required.

– De m onstrated.

Note: Total Ranking is ra ted z e ro when any one of the criteria is rated.

5.2 Technology Evaluation Results of Wet Li mestone Forced Oxidation (LSFO) P r ocess Major equ i p m ent included in each L SFO system is:

• One (1) Absorber common for two (2) un its, with its associated pum ps, piping, instrum e nts and controls

• One (1) Limestone storage and slurry preparation system

• One (1) Gypsum de watering system

• One (1) W a stewater treatm e nt system

• One (1) Flue for two (2) units in a co mmon stack

Table 5-2 below summarizes the te chnology evaluation results of W e t Lim e stone Forced Oxidation system located upstream of the tail-end SCR.

Table 5-2. E valuation of LSFO Syst em Based on Cold-Side SCR Selection (Cost in M i l l i ons)

Units 7 & 8 Units 5 & 6 Incremental Total Cost ($2006) C a p i t a l C o s

t $ 1 4

8 $ 1 6

2

. 8 $ 3

1 0

. 8 First Year O&M $10.5 $8.1 $18.6 L

e

v

e l i z e d O & M $ 1 4

. 8 $ 1 3

. 5 $ 2

8

. 3 C a p i t a l i z e d O & M $ 1 4

8

. 1 $ 1 2

6

. 4 $ 2

7

4

. 5 Total Evaluated Cost $291.3 $294 $585.3

Rankin g (0 -5)
T e

c

h n

o

l o

g

y 5 5 5 C o n

s

t r u

c

t a b

i l i t

y 5 5 5

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Units 7 & 8 Units 5 & 6 I n c r e m e n t a l T o t a l Operating and M a intenance 3 3 3 C o m

m

e r

c

i a l R i s k 5 5 5 P e r f o

r m

a n

c

e Ma r g i n 5 5 5 T o

t a l 2 3 2 3 2 3

Ot

her Fac t ors Scaling Require d No No Unconditional C o mmercial Guarantees Yes Yes



### 5.3 Technology Evaluation Results of Lime Spray Drying (LSD) / Fa bric Filter (FF) System
Major equ i p m ent included in each L S D/FF system is:

• Four (4) LS D/FF system s, one for each unit with associated recycle silo, slurry tank, pum ps , piping, instrum e nts and controls

• One (1) Common Li m e Storage and slurry p r eparation system

• One (1) Common Ash Handling system

• One (1) Common Stack with two (2) flues (total of two stacks and four flues for four units)

Table 5-3 below summarizes the te chnology evaluation results of th e Lime Spray Drying / Fabric Filte r syste m

.
Table 5-3. E valuati on of LSD/FF Syst em (Cost in M i l l i ons)

Units 7 & 8 Units 5 & 6 I n c r e m e n t a l T o t a l Cost ($2006) Capital Cost $151.6 $183.2 $334.8 First Year O&M $16.8 $16.1 $32.9 Levelized O&M $23.6 $19.8 $43.4 Capitalized O&M $228.6 $192.3 $420.9 Total Evaluated Cost $380.3 $375.3 $755.6

Rankin g (0 -5) T e

c

h n

o

l o

g

y 5 5 5 C o n

s

t r u

c

t a b

i l i t

y 5 5 5 Operating and M a intenance 2 2 2 Commercial Risk 5 5 5 Performance Ma rgin 1 1 1 Total 1 8 1 8 1 8

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Units 7 & 8 Units 5 & 6 I n c r e m e n t a l T o t a l Ot

her Fac t ors Scaling Require d No No Unconditional C o mmercial Guarantees Yes Yes



### 5.4 Technology Evaluation Results of Circulating Fluid Bed Scrubber (CFB) / Fabric Filter (FF) System
Major equ i p m ent included in the CF B/FF system is:

• Four CFB/FF system s, one for each unit with ass o ciated recy cle s ilo, s l urry tank, pum ps , piping, instrum e nts and controls

• One (1) Common Li m e storage and hydrated lim e system

• One (1) common ash handling system

• One (1) stack with two flues (total of two stacks and four flues for four units)

Table 5-4 below summarizes the technology evalua tion results of the Circulating Fluid Bed Scrubber/Fabric Filter system

.
Table 5-4. E valuati on of CFB/FF Syst em (Cost in M i l l i ons)

Units 7 & 8 Units 5 & 6 I n c r e m e n t a l T o t a l Cost ($2006) C a p i t a l C o s

t $ 1 4

2

. 3 $ 1 7

0

. 9 $ 3

1 3

. 2 First Year O&M $16.2 $15.2 $31.4 L

e

v

e l i z e d O & M $ 2

2

. 7 $ 1 8

. 7 $ 4

1

. 4 C a p i t a l i z e d O & M $ 2

2

0

. 5 $ 1 8

1

. 3 $ 4

0

1

. 8 Total Evaluated Cost $362.9 $352.1 $715.0

Rankin g (0 -5)
T e

c

h n

o

l o

g

y 4 4 4 C o n

s

t r u

c

t a b

i l i t

y 5 5 5 Operating and M a intenance 4 4 4 C o m

m

e r

c

i a l R i s k 2 2 2 P e r f o

r m

a n

c

e Ma r g i n 3 3 3 T o

t a l 1 8 1 8 1 8

Ot

her Fac t ors Scaling Require d No No Unconditional C o mmercial Guarantees Yes Yes

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### 5.5 Summary of SO 2 

### Control Technology Evaluation Results

The LSFO t echnology has the highest technical ranki ng and the lowest total evaluated cost when

com p ared with th e LSD and CFB processes.

The LSFO process has th e capability to achieve g r eater th an 9 5 % SO 2 

### removal on a long term basis and has greater operational flexibili ty in te rm s of f

u el variab ility than SDA and CFB processes. The expected SO 2 

### rem oval efficiency for the LSD and CF B technology is 92% and 95% respectively.

The LSFO process has th e m o st comm ercial opera ting exp e rience of all th e available processe s
For these reasons, the L SFO technology was retained for evaluation in the to tal project case studies and LSD and CFB technologies were elim inated.

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### 6.0 MULTI POLLUTANT (NO X 

### /SO 2 

### ) CONTROL TECHNO LOGY EVAL UATION

The m o st prom ising of the em erging m u lti-po llutant technolo g ies are the ReACT system from the Japanese company J-Power and th e ECO syste m from the US com p any PowerSpan. Both of these technologies are under developm ent, and have ve ry lim ited application. N e ither technology is installed on units that have si m ilar size and perform a nce requirem e nts as Oak Creek. It is question a ble whether either of these technolog ies w ill be sufficiently developed in time to m e et Oak Creek’s consent decree schedule. The evaluati on of the ReACT and ECO system s was done on a technical/perform ance basis, which is summarized in this section.

6.1 Technology Evaluation Results of J-P o

wer ReACT System
Major equipm ent included in the ReACT syste m for Oak Creek would potentially include:

• Two (2) ReACT adsorber/regenerator system s, one for Units 5 & 6 and one for Units 7 & 8.

• One (1) Ammonia delivery /storage system

.

• One (1) activated coke f eed storage system

.

• One (1) by-product recovery f acility (sulfuric plant).

• One (1) stack with two flues

Table 6-1 below summarizes the technology ev aluation results of the ReACT System

. Table 6-1. Technology Eval uation of ReACT System

Units 5 & 6 Units 7 & 8
Rankin g (0 -5) T e

c

h n

o

l o

g

y 3 3 C o n

s

t r u

c

t a b

i l i t

y 4 4 Operating and M a intenance 2 2 Commercial Risk 1 1 Performance Ma rgin 1 1 Total 1 1 1 1

Ot

her Fac t ors Scaling Require d No Yes Can meet 0.07 lbs/MMBtu NO x E m i s

s

i o

n ? U n p r o

v

e n U n p r o

v

e n Unconditional C o mmercial Guarantees Undetermined Undetermined Chemical Used Activated Coke and Ammonia Activated Coke and Ammonia

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### 6.2 Technology Evaluation Results of PowerSpan ECO System
Major equ i p m ent included in the Po werSpan ECO Sy stem for Oak Creek woul d pote n tia lly in clu d e:

• Two (2) ECO reacto r /ab s orber/W E SPs.

• One (1) Ammonia deliv ery/s t orag e s y stem

.

• One (1) by-product facility (ammonia sulfate)

• One (1) stack with two flues

Table 6-2 below summarizes the technology evalua tion results of the PowerSpan ECO System

.
Table 6-2. Technical Evalua tion of PowerSpan System

Units 5 & 6 Units 7 & 8
Rankin g (0 -5)
T e

c

h n

o

l o

g

y 2 2 C o n

s

t r u

c

t a b

i l i t

y 4 4 Operating and M a intenance 3 3 Commercial Risk 1 1 Performance Ma rgin 3 3 Total 13 13

Ot

her Fac t ors Scaling Require d Yes Yes Can meet 0.07 lbs/MMBtu NO x Yes Yes Unconditional C o mmercial Guarantees Doubtful Doubtful

Chemical Used Ammonia Ammonia



### 6.3 Summary of Multi Polluta nt Cont rol Te chnology Evaluation Results
J-Power ReACT technology was elim inated for further analysis becau se of the risks associated w ith this technology. The risks are:

• Lack of US experience, including PR B coal-fired units

• Lack of an execution plan for engineer ing procurem ent and construction of a ReACT System in the US

• Excess world-wide supply of the process byproduct: Sulfuric Acid

• No ReACT reference p l ant rem oving both high levels of both SO 2 

### and NO X 

### in the sam e system , raising technical qu estions concerning the ability of the system to meet th e leve l of NO x 

### re moval required by W e Energies

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### PowerSpan ECO technology was also elim inated from further consideration for the following

reasons :

• Currently only operating as a 50 MW de m onstration projec t, with opera ting experience o n ly at lower loads.

• Dem onstrate d scale

- up for Oak Cree k will not b e accom p lished in tim e to m e et the consen t decree schedule; p r oj ect would be first-of-a-kind.

• Technology has not been dem onstrated on 100% PRB coal.

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### 7.0 SO 2 

### AND NO X



### COMBINED SYSTEM EVALUATION

Based on the above technology and econom ic evaluations it is determ ined that:

• For Units 5 & 6, LSFO and SCR (cold side and tail end ) tech nologies are suitab l e candidates for com b ined system evaluation.

• For Unit 7 & 8, LSFO and SCR (hot side, co ld side and tail e nd) technologies are suitable candidates for com b ined system evaluation.

• Four com b i n ed system s, Cases 1 to 4 as lis ted below, are formulated and evaluated f u rther to d e term ine which com b ined system would of f

e r the m o st cost ef f

e ctive, technically and commerciall y viable processes for NO x 

### and SO 2 

### em issions control at Oak Creek for Units 5, 6, 7 and 8.

Case 1 LSFO and Tail-end SCRs for all four units

Case 2 LSFO and Cold-side SCRs for all four units

Case 3 LSFO for all four units, Cold-side SCRs for Units 5 & 6, and Hot-side SCRs for Units 7 & 8

Case 4 LSFO for all four units, Tail-end SCRs for Units 5 & 6, Hot-side SC Rs for Units 7 & 8

Evaluation results of the four com b ined system s follow.

7.1 Case 1 LSFO and Tail-end SCRs for all Four U n its Overall System Description

Lim e stone Forced-Oxidation FGD system produci ng wallboard quality gypsum controls the SO 2


### em issions. Tail-End SCR addresses NO x 

### -reduc tio n requir e m e nts. All th e e quipm ent will be located south of Unit 8.

LSFO

The LSFO FGD would c onsist of tw o absorber sy stem s. One absorber sy stem would treat the

com b ined fl ue gas from Units 5 & 6, and the s econd absorber would treat the com b ined flue gas from Units 7 and 8.

Common system s consist of:

• Lim e stone storage and slurry preparation

• Gypsum de watering

• Wastewater treatm ent

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### SCR System

Tail-End SC Rs will be in stalled down s tream of each LSFO system . For this arrang em ent the flue g a s tem p erature must be reheated to raise it to the temperatu r e (>5 2 5 ° F) at which the catalyst is active. Each tail end SCR woul d consists of two (2) ga s-gas heaters, two (2) duct burners or steam coil heaters, and two (2) reactors. The co mbined treate d flue gas from each reactor would be discha rged
to a comm on stack which has two (2) flues, one fo r treated flue gas from Units 5 & 6 and one for treated flue gas from Units 7 & 8.

Stack

One comm on stack with two f l ues downstream of th e SCR system will dis c harge c l ean f l ue gas to atm o sphere.
Technology Evaluation and Cost

Table 7-1 below summarizes the tech nology evaluation results of Case 1.

Table 7-1 Evaluation results of Case 1 (Cost in M i l l i ons)

Total

Tech nol o g

y N O x SO 2 NO x + SO 2

Tail End S CR LSF O Tail End S CR + LSF O Cost ($2006) Capital Cost $178.6 $335.8 $514.4 First Year O&M $9.8 $18.9 $28.7 Levelized O&M $12.9 $28.4 $41.3 Capitalized O&M $125.1 $276.1 $401.2 Total Evaluated Cost $303.7 $612.0 $915.7

Rankin g (0 -5)
T e

c

h n

o

l o

g

y 4 5 9 C o n

s

t r u

c

t a b

i l i t

y 5 5 1 0 Operating and M a intenance 3 3 6 Commercial Risk 5 5 10 Performance Ma rgin 5 5 10 Total (Note 1 ) 22 23 45 Ot

her Fac t ors Scaling Require d No No No Can meet 0.07 lbs/MMBtu NO x E m i s

s

i o

n ? Y e s N A Y e s Unconditional C o mmercial Guarantees Yes Yes Yes

Chemical Used Ammonia Limestone

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### 7.2 Case 2 LSFO and Cold-side SCRs for all Four Units Overall System Description

Lim e stone Forced-Oxidation FGD system produci ng wallboard quality gypsum controls the SO 2


### em ission. Cold Side SCR addresses NO x 

### -reduction requir e ments. All th e equipm ent will be located south of Unit 8.

LSFO

The LSFO FGD would c onsist of tw o absorber sy stem s. One absorber sy stem would treat the

com b ined fl ue gas from Units 5 & 6, and the s econd absorber would treat the com b ined flue gas from Units 7 and 8.

Common system s consist of:

• Lim e stone storage and slurry preparation

• Gypsum de watering

• Wastewater treatm ent
SCR System
Four (4) co ld side SCRs, one f o r eac h Unit, will be used to c ontrol the N O x 

### em issions. Each unit' s cold sid e SCR will be lo cated down stream of its dedica ted e x isting indu ced draf t f a n s and upstr e a m of the new booster induced draft fans. For this arrangem e nt the flue gas temperature m u st be rehea t ed to r a ise it to the tem p erature (>600 ° F) at which the catalys t is active. Each cold side SCR would consists of one (1) gas-gas heater, one (1) duct burne r system or steam coil heater system , and one (1) reac tor.
The treated flue gas from each cold side SCR will be ducted to the new booster inducted draft fan s

.
Stack

One comm on stack with two f l ues downstream of LSFO will discharg e clean f l ue gas to the
atm o sphere.

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### Technology Evaluation and Cost

Table 7-2 below summarizes the tech nology evaluation results of Case 2.

Table 7-2 Evaluation Results of Case 2 (Cost in M i l l i ons)

Total

NO x SO 2 NO x + SO 2 Tech nol ogy Cold Si de SCR LSF O Cold Si de SCR + LSF O Cost ($2006) Capital Cost $190.5 $310.8 $501.3 First Year O&M $15.0 $18.6 $33.6 Levelized O&M $19.8 $28.3 $48.1 Capitalized O&M $191.8 $274.5 $466.3 Total Evaluated Cost $382.3 $585.3 $967.6

Rankin g (0 -5)
T e

c

h n

o

l o

g

y 3 5 8 C o n

s

t r u

c

t a b

i l i t

y 5 5 1 0 Operating and M a intenance 3 3 6 Commercial Risk 4 5 9 Performance Ma rgin 5 5 10 Total 2 0 2 3 4 3

Ot

her Fac t ors Scaling Require d No No No Can meet 0.7 lbs/MMBtu NO x E m i s

s

i o

n ? Y e s N A Y e s Unconditional C o mmercial Guarantees Yes Yes Yes

Chemical Used Ammonia Limestone

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### 7.3 Case 3 LSFO for all Four Units, Cold-side S CR for 5 & 6, a nd Hot-side SCRs for 7 & 8 Overall System Description

Lim e stone Forced-Oxidation FGD system produci ng wallboard quality gypsum controls the SO 2


### em ission. Hot side SCR addresses NO x 

### -reduction requirem e nts for Units 7 & 8. Cold Side SCR addresses NO x 

### -reduc tio n requir e m e nts f o r Units 5 & 6. All the equipm ent will b e lo cated sou t h of Unit 8.

LSFO

The LSFO FGD would c onsist of tw o absorber sy stem s. One absorber sy stem would treat the

com b ined fl ue gas from Units 5 & 6, and the s econd absorber would treat the com b ined flue gas from Units 7 and 8.

Common system s consist of:

• Lim e stone storage and slurry preparation

• Gypsum de watering

• Wastewater treatm ent
SCR System
Hot side SCRs, one for Unit 7 and o n e for Unit 8, would be installed b e tween each existing un it' s

econom izer and air preheater.

Two Cold Side SCRs will be ins t alled upstream of one common 5 & 6 LSFO system . For this
arrangem ent the flue gas must be reheat ed to raise it to the temperatu r e (>6 0 0 ° F) at which the catalyst is active. Each cold side SC R would cons ist of two (2) gas-gas heaters, two (2) duct burner system s or steam coil heater sy stem s, and two (2) r eactors. The com b ined treated flue gas from eac h reactor would be discharged to the comm on LSFO system

. Technology Evaluation and Cost

Table 7-3 below summarizes the tech nology evaluation results of Case 3.

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### Table 7-3 Evaluation Results of Case 3 (Cost in M i l l i ons)

Total

NO x SO 2 NO x + SO 2 Tech nol ogy Hot Si de & Cold Si de SCR LSF O SCR + LS FO Cost ($2006) Capital Cost $193.4 $325.6 $519.0 First Year O&M $13.4 $18.8 $32.2 Levelized O&M $17.7 $28.1 $45.8 Capitalized O&M $171.1 $272.3 $443.4 Total Evaluated Cost* $364.5 $598 $962.5

Rankin g (0 -5)
T e

c

h n

o

l o

g

y 4

. 5 5 9

. 5 C o n

s

t r u

c

t a b

i l i t

y 3 5 8 Operating and M a intenance 2.5 3 5.5 Commercial Risk 4 5 9 Performance Ma rgin 5 5 10 Total 1 9 2 3 4 2

Ot

her Fac t ors Scaling Require d No No No Can meet 0.7 lbs/MMBtu NO x Emission? Yes NA Yes Unconditional C o mmercial Guarantees Yes Yes Yes

Chemical Used Ammonia Limestone *Including $18M power penalty.



### 7.4 Case 4 LSFO for all Four Units, Tail-end S CRs for 5&6, and Hot-side SCRs for 7&8 Overall System Description

Lim e stone Forced-Oxidation FGD system produci ng wallboard quality gypsum controls the SO 2


### em ission. Hot side SCR addresses NO x 

### -reduction requirem e nts for Units 7 & 8. Tail End SCR addresses NO x 

### -reduc tio n requir e m e nts f o r Units 5 & 6. All the equipm ent will b e lo cated sou t h of Unit 8.

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### LSFO

The LSFO FGD would c onsist of tw o absorber sy stem s. One absorber sy stem would treat the

com b ined fl ue gas from Units 5 & 6, and the s econd absorber would treat the com b ined flue gas from Units 7 and 8.

Common system s consist of:

• Lim e stone storage and slurry preparation

• Gypsum de watering

• Wastewater treatm ent
SCR System
Hot side SCRs, one for Unit 7 and o n e for Unit 8, would be installed b e tween each existing un it' s

econom izer and air preheater.

One Tail-En d SCR will be installed downstream of one common 5 & 6 LSFO system. For this
arrangem ent the flue gas must be reheat ed to raise it to the temperatu r e (>5 2 5 ° F) at which the
cata l yst is ac tive. Each ta il end SCR would consist of two (2) gas- gas heaters, two (2) duct burner system s or steam coil heater system s, and two (2) reactors. F o r this configuration, a single stack would be installed; one flue would discharge dry flue gas from the Units 5 & 6 SCRs and the other flue would discharge saturated flue gas from the Unit 7 & 8 LSFO, with potential associated stack design issues.
Technology Evaluation and Cost

Table 7-4 below summarizes the tech nology evaluation results of Case 4.

Table 7-4 Evaluation Results of Case 4 (Cost in M i l l i ons)

Total

NO x SO 2 NO x + SO 2 Tech nol ogy Hot Si de & Tail End SCR LSF O SCR + LS FO Cost ($2006) Capital Cost $187.5 $325.6 $513.1 First Year O&M $11.1 $18.8 $29.9 Levelized O&M $14.8 $28.2 $43.0 Capitalized O&M $143.4 $274.1 $417.5 Total Evaluated Cost* $ 3

3

0

. 9 $ 5

9

9

. 6 $ 9

3

0

. 5

Rankin g (0 -5)
T e

c

h n

o

l o

g

y 4

. 5 5 9

. 5

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NO x SO 2 NO x + SO 2 Tech nol ogy Hot Si de & Tail End SCR LSF O SCR + LS FO
C o n

s

t r u

c

t a b

i l i t

y 3 5 8 Operating and M a intenance 2.5 3 5.5 Commercial Risk 4 5 9 Performance Ma rgin 5 5 10 Total 1 9 2 3 4 2

Ot

her Fac t ors Scaling Require d No No No Can meet 0.7 lbs/MMBtu NO x Emission? Yes NA Yes Unconditional C o mmercial Guarantees Yes Yes Yes

Chemical Used Ammonia Limestone *Including $18M power penalty.

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### 7.5 Comparison of Cases 1 to 4
Table 7.5 summarizes the total proce ss capital, evaluated cost with pow er penalty and overall system ranking of Cases 1 to 4.
Table 7-5. S u mmary of C ases 1 to 4 (Cost in Millions)

Cases Unit # System Component To tal Process Capital To tal Evaluated

Cost Power Ou tage Penalty Total Evaluated

Cost + P e n a l t y R a n k i n g
1 All Four LSFO +Tail End SCR $514 $916 $0 $916 45 2 All Four LSFO + Cold Side SCR $501 $968 $0 $968 43 3 Units 5 & 6 Units 7 & 8 LSFO +Cold Side SCR LSFO + Hot Side SCR $ 5

1 9 $ 9

4

5 $ 1 8 $ 9

6

3 4 2

4 Units 5 & 6 Units 7 & 8 LSFO +Tail End SCR LSFO + Hot Side SCR $ 5

1 3 $ 9

1 3 $ 1 8 $ 9

3

1 4 2



### LSFO and Tail-end SCR (Case 1) have a total ev al uated cost of $916 m illion and an o v erall rank in g of 45. Due to cleaner flue gas conditions downstr eam of LSFO system , th e tail-end applications have technical benefits when com p ared to the cold side SCR applic ation s

.
LSFO and Cold side SC R for all units (Case 2 ) h a s a to tal ev aluated cost of $968 m illion and an overall ranking of 43. Both the LS F O and SCR are proven technologies.

Hot side SCR f o r Units 7 & 8 (Case 3 & 4) pose high re trof it dif f i cultie s r e sulting in h i gher than standard capital cost, and power outage pe nalties due to extended outage tim e

.
Based on the overall closeness of bot h the total estim ated cost and te chnical ranking, all four cases should be retained for further exam ination during prelim inary engineer ing before a final selection is

m a de.

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### 8.0 CONCLUSIONS AND RECOMMENDATIONS

8.1 Process Selection
This study evaluated the following technologies:

A. SO 2 

### Re m o val (FGD) Processes

• Lim e stone Forced Oxidation (LSFO)

• Lim e Spray-Dryer with Baghouse (LSD)

• Circulating Fluid Bed with Baghouse (CFB)

B. NO X 

### R e m o val P r oces ses

• Mobotec R O FA / ROTAMIX

• Mitsu i NOxStar

• Foster W h eeler Low NO x 

### Burners

• SCR (Hot Side, Cold Side, and Tail-end)

C. Multi-pollutant Processes

• J-Power ReACT Technology

• PowerSpan ECO Technology

Based upon the analyses presented in this report, LSFO and SCR system s are recommended for use on Oak Creek Units 5-8. Som e of the ke y considerations are listed below.

NO x 

### Reduction
The design criterion is to reduce NO x 

### em issions to less than .07 lbs/m b tu. The SCR pr ocess can achieve this perf orm a nce with m a rgin to spare.

The SCR pr ocess exhibits a higher evaluated ra nking over the other eval uated technologies. The overrid i ng f actor is th e num b er of successf ully ( r el iability /av a ilab i lity) o p erating SCR system s in the USA and overseas.

The SCR pr ocess has greater operational flex ib ility com p ared with the o t her choices.

Mobotec technology is prom ising but not yet proven on PRB c o al. Also low inlet NO x 

### em issions level is a harder application than the current experience of this system

. Mitsui has not convincingly dem onstrated that their NOxStar sy stem can achieve the required NO x 

### reduction. T h ere is no sp ace at Oak Creek for ac commodating polishin g SCRs in the ductwork downstream of the econom i zers, which is a featu r e of the NOxStar Plus s y stem

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### SO 2 

### Reduction
The design criterion is to reduce SO 2 

### em issions to less than 0.07 lb s/MMBtu. The LSFO process can achieve this perf orm a nce with m a rgin to spare.

The LSFO process exhibits a higher evaluate d ranking over the SDA and CFB technologies. The overrid i ng f actor is th e num b er of successf ully ( r eliability /av a ilab i lity) o p er ating LSFO system s in the USA.

Af ter resolu tion of initial problem s in the ea rl y developm ent phase, the LS FO process is now considered highly reliable. The forced oxidation f eature produ ces comm er cial g r ade g ypsum that can be sold for wall board m a nufacturing use.

The LSFO process is cap able of achieving greater than 95% S O 2 

### rem oval efficiency. In com p arison the SDA can achieve 93% and CFB can achieve 95% SO 2 

### removal efficiency.

The LSFO process ha s g r eater ope rational f l ex ibi lity in te rm s of f

u els used at the bo ile r s

. The LSFO process has th e lowest ev aluated cost o f the alternatives com p ared. The LSFO process has also the highest evaluated ranking

Installation of an LSFO system fo r the Oak Creek units presents th e possibility of further shared savings with the neighboring Elm Road project by utilizing the capac ity of common system s such as lim estone storage and handling, gypsum storage and ha ndling, and the wastewater treatm e nt system.
Multi-polluta nt (NO x 

### plus SO 2 

### ) Systems
J-Power has not convincingly dem o nstrated that they could make a commercial offering of their system in the Oak Creek project tim e fram e.
PowerSpan ECO syste m is a potential altern ativ e; however, PowerS pan has lim ited industry experience a nd a high de gree of scaling will be re qui red f o r Oak Creek ca pacity. The technica l r i sk is considered high. Overall ranking is lowe r than the com b ined LSFO a nd SCR system

.
For reasons stated abov e the SCR and LSFO co mbined sy stem is reco mmended for Oak Creek units

.
8.2 Site and New Plant Area Considerations
The Study confirm e d that there is adequate space at the site to locate com b ined SO 2 

### and NO x 

### system s on the South sid e of the exis ting plan t. T h e area requ ired to acco mmodate the new equipm ent will require excavating s o m e bluff areas adjacent to the wes t o f the new plant area. Two new auxiliary transform e rs will b e lo cated sou t h w est of the existing p l an t. The underg round utilities that are present in the area woul d be abandoned or relocated base d on further investigation. Som e preassembly work needs to be performed in areas not in the immediate vicinity of the plant. Certain auxiliary system equipment such as reagent st orage and preparation, byproduct storage and handling facilities, ch em ical storage, et c. were located on the bluff to reduce cos t o f excavation for the

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### purposes of this study. However, during detail design, areas adjacent to the plant will be analyzed for locating thes e facilities to reduce p i p i ng and electrica l m a terial costs and also to m i nimize operating and m a intenance costs.

A new Stack with 2 flues, one for Units 5 & 6 flue gas and the other for Units 7 & 8 flue gas is required. The stack will be located on the south side of the new plant tow a rd s the existing ash ponds. The height of the new stack is to be determ ined based on dispersion analysis and regulatory code requirem e nts. The new stack will be of concrete construction; the m a terials of construction of the flues will be determ ined through life and economic stud ies to be perform e d later.

The flue gas ductwork from the existing ID fan(s) discharge to the new plant will be routed on the east side of the existing plant. Portions of the Units 7 & 8 ductwork transporting gas to the 7 & 8 existing chimney will b e no longer needed for Units 7 & 8. Therefore, these ductwo r k sections will be utilized and m a de part of Units 5 & 6 gas ductwork to the new plant. Other ductw ork routing options were studied an d found to be eith er not practical or econom ical . Round ductwork will be used where possible. Combining two (2) units ' gas flow into comm on ductwork m a y provide opportunities for cost savings, but w ill increase the potential for duc twork corros i on. This will b e studied during detailed design.

The SCR location will require further study bef o re final configuration selection:

• Tail-end SCRs have the potential for longer ca talyst life, sm aller re actor size, and lower operating temperature

• Cold-side S CRs m a y ha ve sim p ler and less-co stly ductwork arrangem ents, and m a intain unitized operation

• Hot-side SC Rs elim inate the gas/gas heat exch an ger and natu ral gas usage, but have increased im pact on the existing station

The booster fans receiv e the flue gas through th e ne w gas ductwork from t h e existing ID fans. These new booster fans were assum e d to be axial fans. F u rt her study is required to com p are axial and radial fans. The new design assum e s that tw o booster fans are prov ided for each unit. Poten t ial co st savings with the use of single booster fan for each unit will be studied.

Materials of construction of various com ponents of the LSFO FGD system will be determ ined based on process conditions an d industry experience.

The designs assum e d in this report do not share fa cilities with Elm Road. However, it is expected that the lim e stone unloading and l ong term storage could be at the existing dock area designated for this purpose for Elm Roa d plant. Lim e stone transf er between f acili ties would be by truck. A shorter duration clo s e-in s t orag e is plann e d o n the W e st Side of the new facility. L i kewise gyp sum produc ed at Oak Cree k plant cou l d be truck e d to the Elm Road dock. Future stud ies will inclu d e sharing o f system s with the Elm Road plant.

A wastewater treatm e nt facility is in cl uded in the scope of the new facility.

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### Two auxilia ry tran sf ormers will re ce ive electric a l f eed f r om the exis ting s w itchyard. T h ese transf orm e rs will m eet th e load dem a nd f r om the new em issio n s contro l plant.

Electrica l an d contro l ro om s will be located with in the new p l ant a r ea ba s e d opera tion and

m a intenance consider ations. A DCS system will be provided f o r plant con t rols with monitor i ng inputs to the m a in plant control room.

A tem porary m a terials unloading dock to receive construction m a terial d e live r ie s tr a n sported by barges should be evaluated. This m a y allow shipm e nt of larger assem b lies to the site to reduce construction tim e and cost.

Areas for craft parking and equipm e n t storage have been identified, and need to be further studied from efficient m ove m e nt point of view.

8.3 Construction Considerations
The new plant constructability issues were stud ied to ensure there are no issues that could significantly increase erection duration and cost s. Am ong the construction issues studied are:

• The ductwork routing from the existing Units 5 & 6 ID fan discharge to the inlet of booster fans. This ductwork runs in a North-South direction along east of the boiler house. Large sections of ductwork can be erected utilizing cranes that travel o v er the ash h a ul road. The construction sequence and technique needs to be f u rther developed taking into cons ide r ation the ex isting p l an t operations. Portions of Units 7 & 8 return du ctw o rk to th e stack will b e used as new Units 5 & 6 ductwork for cost savings. The ductwork supports and foundations will need to be designed to take into consideratio n existing structures and underground utilities.

• A tem porary m a teria l s u n loading do ck c ould be built on the lakeshore adjacent to the new facility. This would allo w transportation of m odul arized and
preassem b led sections to the site ut ilizing barges, which m a y r e sult in considerable savings in sc hedule and construction cost.

• Crane and material m ovem e nt requires the new plant construction to begin with Unit 8 and f o llow with Units 7

, 6, and 5 in that order. New Unit 7 & 8 equipm ent is loca ted W e st of 5 & 6 and w ill be placed in op eration firs t to free up the portions existing Units 7 & 8 ductwor k that will be used for Units 5 & 6.

• Units 5 & 6 and 7& 8 have common flues, therefore each p a ir of units will be started up together. The prelim inary pr oject schedule is based on a 6-m o nth gap between the comm is sioning of Units 7 & 8 and Units 5 & 6.

• Installation of certain n e w plant equi pm ent such as booster fans will be sequenced to allow m a terial m ove ment to the areas north of the fans. "L eaveout" equipm ent and "leave-out" steel m a y be necessary for access to certain erection areas.

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### • Further investigations are needed to determ ine the underground utility reloc a tion s

.

• Excavation of certain b l uff areas m a y be required to accom modate the
perm anent plant s t ructures.

• It is b e lieve d that suf f i cient cr af t lab o r will b e av ailab l e f o r th e new f a cility construction in the window of 2008 t h rough 2012. During the developm ent of the project execution pro cedures, detailed labor su rveys will be conducted which will include th e study of any new construction projects that m a y be on the anvil.

• The existing plant tie -ins to the new f aci lity will b e genera lly be com p leted in the planned outages of the existing units . The tie-in work will be carefully coordinated not to cause interruptions to the existing plant generation.

• Detailed plant testing and start-up pro cedures will be developed to allow

sm ooth transition of the new plant from c onstruction to start-up and from startup to perm anent plant operation.

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