### Via Federal 

### Express 

# JUL 3 1 2008 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8 1595Wynkoop Street DENVER, CO 80202-1129 Phone 800-227-8917 http://www.epa.gov/region08


### Ref: 8ENF-L

Mr: Terry O'Clair Director, Division ofAir Quality North DakotaDepartmentofHealth 918 E. Divide Avenue Bismarck, ND 58501-1947 Re: Transmittal ofEPA's Comments on the North DakotaDepartment ofHealth's PreliminaryNOxBACT Determination for Milton R. 

### Young Station DearMr. O'Clair: This lettertransmits the United States Environmental Protection Agency's ("EPA") comments on the North DakotaDepartmentofHealth's (NDDH's) Preliminary BestAvailable Control Technology (BACT) Determination for Nitrogen Oxides (NOx) for Milton R. 

### Young Station (MRYS), Units 1 and 2 thatwas dated June 2008 and published for public comments beginning on June 11,2008 and ending on July 11,20081 

### (hereinafter, "theNDDH BACT determination"). EPA asserts thatthe operatorofMRYS, MinnkotaPowerCooperative, Incorporated ("Minnkota"), failed to meet its burden ofdemonstrating to NDDH that selective catalytic reduction (SCR) is technically infeasible under Step 2 ofthe Top-Down BACT analysis and NDDH failed to provide a reasonedjustification for its elimination ofSCRas a control option at MRYS. EPA is providing additional information supporting the technical feasibility ofSCR at MRYS forNDDH to consider and include in the administrative record for NDDH's Final BACT determination. The comments and additional documents supplementprevious correspondence between EPA andNDDH concerning the October 2006 BACT analysis (hereinafter, "the MinnkotaBACT analysis") thatwas submittedby Bums & McDonnell ("B&McD") onbehalfof Minnkota. EPA submittedprevious comments to NDDH on the MinnkotaBACT analysis in letters dated January 11,2007, January 26,2007, and October4,2007. NDDH has not adequately responded to many ofthe substantive issues raised inthese letters.

1 Per July 8, 2008 letterfrom NDDH to EPA, the public commentperiod was extended until close ofbusiness on August 1, 2008.EPA Comments onNDDH Preliminary NOx BACTDetermination for MRYS



### As described in more detail inthe Enclosure, the basic premise ofthe NDDH BACT determination is unreasonable and unsupported because itrelies on the lack ofa demonstrated application ofSCRtechnology to North Dakota lignite-fired cyclone boilers to eliminate from considerationthe application ofSCRto the units at MRYS.2 

### This premise is both an incorrect application ofEPA's "Top-Down" BACT procedure, as outlined under ChapterB ofthe "New Source Review Workshop Manual---Prevention ofSignificantDeterioration and Nonattainment AreaPermitting," (Draft October 1990) (EPA's NSR Manual)3 and also fails to considerthe widespread and successful application ofSCRto utility boilers worldwide andto other industrial stationary source types that have extremely varied and challenging flue gas characteristics. NDDH's BACT determination uses the lack ofdemonstrated application ofSCR specifically to cyclone boilers fired with lignite from the CenterMine to conclude that the SCRtechnology in any form would be technically infeasible and thus eliminated from consideration ofthe TopDownBACT analysis. SCR systems are being successfully applied to virtually every kind ofstationary source and fuel type worldwide. In meeting these varied and significant challenges for the widespread deployment ofSCRtechnology, system designers must always tailor the specifics ofSCR applicationto the varied conditions at each facility and the most suitable location for installing the system. Inthe most challenging situations with highly variable flue gas characteristics containing potential catalystpoisons in significantconcentrations, designers have successfully used the tail-end orlow-dust SCRdesign. The responses from the vendor query thatwas submittedby Minnkotaand further pursued by EPA clearly confirmthat SCRis an available control optionthatcan be applied to MRYS without the need for any pilottesting. As detailed inthe Enclosure, vendors have statedthat a tail-end SCR systemwould without question address the uncertainties and technical challenges. associated withfiring North Dakotalignite in a cyclone boiler described in the NDDH BACT

2 The focus ofEPA's comments herein is on SCRbecause this is the "top" add-on control option (Le. has the highestpotential degree ofcontrol) listed in the NDDH BACT determination. As such, EPA's primary concern is thatthe "top" control option has been improperly eliminated from consideration. However, EPA has previously commented on other control options (Hydrocarbon Enhanced SelectiveNon-Catalytic Reduction, Reburn with Selective Non-Catalytic Reduction (SNCR), and Rich Reagent Injection with Advanced Separated Overfrre Air and with SNCR) also being improperly eliminated as being technically infeasible in the MinnkotaBACT analysis and those comments stand. While the NDDH BACT determination for these other control options cites information provided by Minnkota, there is no mention orresponse to the EPA's previous comments. EPA requests thatNDDH consider and respond to previous EPA comments priorto making the final BACT determination for these control options. 3 The ConsentDecree (Civil Action 1:06-CV-034) requires thatthe NDDH make its NOx BACT Determination, "in accordance with the applicable federal and state statutes, regulations, and guidance cited in the defmition of"NOx Top-Down BACT analysis," which requires the BACT analysis to, "be carried out in accordance with the provisions ofChapterB ofEPA's 'New Source Review Workshop Manual- Prevention ofSignificant Deterioration and NonattainmentArea Permitting,' (Draft 1990)." See page 7 ofthe Consent Decree. 

### -2-EPA Comments onNDDH Preliminary NOx BACT Determination for MRYS 

### determination. 

### Both SCR systemsuppliers andcatalystsuppliers clearly believe tail-endSCR 

### is an availableNOx 

### controloption atMRYS andwouldnotrequire anypilottesting/or application atMRYS. Vendorresponses also indicate that a high-dust application is commercially available atMRYS, albeit with the same concerns they-routinely have aboutthe uncertainties involved in applying SCRto any different fuel type and acknowledging the challenge to maintainthe propertemperature range for catalystperformance and life at MRYS. EPA submits the followingEnclosures for inclusion inthe administrative record: (I) supplemental information and experttechnicalopinion report (including references) of consultant, Hans Hartenstein, President ofEvonikEnergy Services LLC, (2) specific comments by EPA on the NDDH BACT determination, and (3) additional documentationto be considered inNDDH's final BACTdetermination.4 

### Mr. Hartensteinhas included copies ofmost ofthese references with his report. EPA believes the remainder ofthe references are public documents and generally available. EPA can provide copies ofthese documents upon requestby NDDH. Ifyou would like to discuss any ofthese matters, please call CynthiaReynolds at (303) 312-62006 or BrendaMorris at (303) 312-6891.

Andre M. Gaydosh AssistantRegional Administrator Office ofEnforcement, Compliance and

Environmental Justice Enclosures

cc: David Glatt, NDDH (w/o Enclosures), DeanHaas, NDDH (w/o Enclosures), Jerry MacLaughlin, USDOJ (w/o Enclosures), JeffKodish, OECA, (w/o Enclosures), Ron Rutherford, EPA (w/o Enclosures), BrendaMorris, EPA (w/o Enclosures), Hans Buenning, EPA Amy Platt, EPA (w/o Enclosures), Douglas Latimer, EPA (w/o Enclosures),

4 Enclosure 3 contains documents that EPA received from Bums & McDonnell in response to an information request submitted by EPA. Some ofthese documents may contain confidential business information and should be handled accordingly. 

### -3-

## ENCLOSURE 1 HANS HARTENSTEIN'S EXPERT OPINION REPORT & REFERENCES (ON CD - 2 COPIES)

### Feasibility ofSCRTechnology for NOx Control Technology for the Milton R. Young Station, Center, North Dakota

Expert Report of

Hans Hartenstein

ON BEHALF OF THE

UNITED STATES DEPARTMENT OFJUSTICE

July2008

A- 1TABLE OF 

### CONTENTS Page 1. INTRODUCTION AND OVERVIEW 3 1.1 Information Required for the Expert Report 3 1.2 Purpose ofthe Report 3 2. SUMMARY OF CONCLUSIONS 4 3. QUALIFICATIONS 6 4.

.THE MILTON R. YOUNG STATION: BACKGROUND 8 5. SCRTECHNOLOGy 8 6. SCREVALUATION 19 6.1 Variability ofFuel Composition : 23 6.2 Results ofthe Coyote PilotTesting 24 6.3 Soluble Sodium 27 6.4 Differences in Flue Gas Composition 29 6.5 Experience ofBums and McDonnell and Sargent and Lundy 30 6.6 Development Stage ofHigh-Dust SCR 32 6.7 Temperature Variations 33 6.8 CatalystErosion 33 6.9 CatalystPoisoning, Blinding and Plugging 34 6.10 Lack ofPilot Scale Testing Data 36 6.11 Lack ofVendor Guarantees 38 6.12 Review Authority 39 6.13 Conclusions 39 7. VENDOR QUERY TAIL-END SCR 46 8. SUMMARy 49 Appendix A: Data and Information Considered 51 Appendix B: SCRVendor Query Correspondence 57 Appendix C: Selected Papers Authored in LastTen Years 67 Appendix D: Resume 73

A-2

### 1. INTRODUCTION AND OVERVIEW 1.1 Information Required for the Expert Report
The following is a listing ofthe items provided with this report: (1) This report contains my personal opinions, conclusions and the reasons therefore. (2) The body ofthe report and Appendix A listthe data and other information considered in forming these opinions. (3) Appendix B provides a copy ofthe e-mail correspondence with several selective catalytic reduction (SCR) catalyst manufacturers and SCR equipment vendors concerning the technical feasibility oftail-end SCR (TESCR). (4) Appendix C includes a listing ofpublications authored during the pastten years. (5) Section III presents a statement ofmy qualifications; my resume is attached as Appendix D. (6) I am being compensated for the preparation ofthis report and my testimony by the U.S. Department ofJustice. (7) I have provided previous testimony within the preceding four years as an expert attrial orby deposition.


### 1.2 Purpose ofthe 

### Report
This report is written under a consulting contract and pursuantto a request from the DepartmentofJustice (DOJ) for an analysis ofwhether or notthe SCRtechnology would be a technically feasible and available technology for the reduction ofnitrous oxides (NOx) for installation atthe Milton R. Young Station located near Center, North Dakota. A preliminary Best Available Control Technology (BACT) determination for control ofNOx for the M.R. Young Station conducted by the Division ofAir Quality ofthe North Dakota Department ofHealth1 (the Department) concludes thatthe SCRtechnology is not

l Preliminary BestAvailable Control Technology Determination for Nitrogen Oxides for M.R. Young Station Units 1 and 2, Division ofAir Quality NO DepartmentofHealth, 918 E. Divide Avenue, Bismarck, NO, June 2008. 

### A-3technically feasible atthis time. I was asked to review the information in and provided by this preliminary BACT determination and render an expert opinion concerning the technical feasibility ofthe SCRtechnology for retrofit atthe M.R. Young Station.



### 2. SUMMARY OF CONCLUSIONS
In summary, and for the reasons described herein, I have concluded thatthe SCRtechnology is technically feasible and principally available for installation at both units atthe Milton R. Young Station for NOx reduction. I have further concluded that even though the high-dust SCR (HDSCR) principle was investigated in some detail priorto the BACT determination: The depth ofthe investigation concerning the technical feasibility ofHDSCR in this case by means ofpilottesting conducted at the Coyote Station (Coyote Pilot Testing) was insufficient and the conclusions drawn from this pilottesting were speculative and premature. Virtually no investigation ofthe technical feasibility oflow-dust SCR (LDSCR) and TESCR was conducted at all and both distinctly different SCRprinciples were incorrectly treated as ifthey would be essentially the same. The HDSCR Coyote Pilot Testing was ill-designed and inadequately conducted. The data generated by the Coyote Pilot Testing for these reasons is inconclusive and meaningless ofthe purpose ofthis determination. The conclusions suggested by the Departmentbased on the datapresented are not reasonably founded butpremature, purely speculative and mostly incorrect. Consequently, it is my opinion thatthe conclusions presented by the North Dakota DepartmentofHealth in the BACT determination2., namely, thatthe SCRtechnology is not technically feasible atthis time for both units atthe M.R. Young Station, is wrong. Such a conclusion cannot be drawn correctly based on the available data. The SCRtechnology must be consideredprincipally, technically feasible for Minnkota's Milton R. Young Station. This is even true for HDSCR even though not without significantbuttechnically resolvable challenges, which may result in HDSCR not being the economically most advantageous SCR principle. However, whetherHDSCR, LDSCR or TESCR is the economically most viable SCR solution for M.R. Young is beyond the scope ofthis report. Finally, I have concludedthat no sufficiently detailed investigation was conducted for LDSCR and/orTESCR in this case and the record ofinvestigation provided by the

£. Preliminary BestAvailable Control Technology Determination for Nitrogen Oxides for M.R. Young Station Units I and 2, Division ofAir Quality ND DepartmentofHealth, 918 E. Divide Avenue, Bismarck, ND, June 2008. 

### A-4Department is insufficient, inadequate and incomplete. Both ofthese SCRprinciples were incorrectly treated by the Department as being essentially the same, which is incorrect and unacceptable as the flue gas composition and characteristics entering a LDSCR are completely different from the one entering a TESCR. The statement made by the Departmentthat none ofthe various principles ofthe SCR technology (HDSCR, LDSCR, TESCR) can be considered applicable and technically feasible at this time is not only purely speculative but factually incorrect. As a matter offact a quick vendor survey conducted by me confirmed that all contacted vendors consider TESCR as being unquestionably technically feasible, available and applicable for M.R. Young Station. This was not only unanimously confirmed by all leading catalyst manufacturers (Argillon, CERAM, Cormetech, Haldor Topsoe and Hitachi) but also by leading SCR equipment vendors (Alstom, BabcockPower and Babcock & Wilcox). Furthermore, these SCR equipment vendors and catalyst manufacturers confirmed my opinion by stating thatthey also consider LDSCR as technically feasible and probably even HDSCR, however not without significantbut resolvable technical challenges such as limiting the boiler outlettemperature variations to a range tolerable for SCR catalyst and eliminating the popcorn ash problem. The temperature variations at the boiler outlets appearto be the biggest hurdle for the application ofHDSCR atthis time; however, this issue is considered to be technically resolvable as indicated by Babcock & Wilcoxd
, who supplied both boilers at M.R. Young Station. Answering the question ofwhether or notthe extent ofmodifications of existing equipmentrequired to resolve the temperature variation issue makes HDSCR economically less attractive in comparison to LDSCR oreven TESCR is beyond the scope of this report. However, it is my opinion thatthe available data presented in the Department's BACT determination± is insufficient, inconclusive and interpreted largely incorrectly when concluding the HDSCR is technically infeasible. This conclusion cannot be supported by the available data at all. Furthermore, concluding that LDSCR and/or TESCR are nottechnically feasible based on the available data is incorrect, since no relevant data was presentedthat supports such a conclusion in any way. Based on my more than 20 years ofSCRexperience and my evaluation ofthe vendor responses, it is my opinion thatthe SCRtechnology is technically feasible and principally available for installation at both units atthe Milton R. Young Station for NOx reduction. The only design engineering challenge is the proper selection ofthe best suitable type ofSCRprinciple.2. to be applied and the correct SCR process and catalyst design. This, however, is neither a question oftechnical feasibility nor ofapplicability or availability ofthe SCRtechnology but simply a question ofeconomics.

;). E-mail from Steve Moormann (Babcock &Wilcox) to Robert Blakley (Bums & McDonnell) dated July 18, 2007

. .1. Preliminary Best Available Control Technology Determination for Nitrogen Oxides for M.R. Young Station Units 1 and 2, Division ofAir Quality NO DepartmentofHealth, 918 E. Divide Avenue, Bismarck, NO, June 2008.
2. Defined by its location on the flue gas pass as HDSCR, LDSCR or TESCR. 

### A-5

### 3. QUALIFICATIONS
I have been involved in the business development, proposal engineering and estimating, project management, process and design engineering, component and equipment procurement, construction, erection, commissioning and start-up and operation ofair pollution control equipment for utility and industrial powerplants as well as waste incinerators (municipal waste, hazardous waste, sewage sludge, medical waste etc.) in a variety ofcapacities for overtwenty years. I began my career in the field ofair pollution control in 1983 as a staffengineerworking for Mercedes-Benz in automobile engine development adapting standard type European automobile engines with catalytic converters, secondary air injection systems, exhaust gas recirculation systems etc. in orderto comply with more stringent emission regulations in entities such as California, the U.S. (48 states), Japan etc. In late 1987, I accepted aposition with L&C SteinmUller GmbH in Germany, which was one ofthe leading engineering and equipmentvendors supplying power utility boilers, including the associated airpollution control equipment. Initially, my field ofresponsibility included business development for all environmental control technologies (air, water, waste) in Southern Germany. In 1990, I became DepartmentManager ofthe Department ofGas Cleaning for waste incineration facilities. In 1993, I became General Manager for Flue Gas Cleaning at L&C SteinmUller. Between 1988 and 1999, I was personally fully involved in the following retrofit phases in Europe: Retrofitting all fossil fuel fired boilers (utilityand industrial) with a thermal heat input ofmore than 300 MW with flue gas desulfurization (FGD) systems ensuring a continuous S02 removal efficiency ofat least 85% at all times, mostly wet limestone forced oxidation (LSFO) FGDs producing wallboard quality gypsum as a byproduct. This retrofitphase started in Western Europe in the late 1970s and ended in Eastern Europe in the late 1990s. FGD retrofits focused on Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, Germany, Greece, Holland, Hungary, Poland, Slovenia, Slovakia, Spain, Sweden, Turkey and the U.K. Retrofitting all fossil fuel fired boilers with a thermal heat inputofmore than 300 MW with nitrous oxide removal (DeNOx) systems ensuring aNOx emission rate of less than 100 ppmQat all times, almost exclusively selective catalytic reduction (SCR) DeNOx systems. This retrofitphase started in Europe in the mid 1980s and is still ongoing. SCR retrofits focused on Austria, Belgium, Denmark, Finland, Germany, Holland, Italy, and Sweden. Retrofitting all waste incineration facilities regardless ofthe type ofwaste (municipal, industrial, hazardous, sewage sludge, medical etc.) with extensive flue gas cleaning

2 Atthe following flue gas characteristics: NOx concentration by volume on a dry basis @ 5% O2, 1 atm., 273 K. A-6systems for the removal ofacid gases (SOx, HCI, HF), NOx, particulate matter (PM), heavy metals including mercury (Hg), cadmium (Cd), lead (Pb) and numerous others as well as dioxins (PCDD) and furans (PCDF). This retrofitphase started in Europe in the early 1990s and is still ongoing. Waste incineratorretrofits focused on Austria, Denmark, Finland, France, Germany, Holland, Norway, Sweden, and the U.K. In 1999, Ibecame a co-founder and Managing DirectorofE&EC

- Energy & Environmental Consultants GmbH, an international engineering consulting firm with offices in Germany and a representation in the U.S. Through E&EC I assisted a German SCRcatalyst manufacturer in a concentrated effort to supply SCR catalyst and system expertise to the North American market. Also, through E&EC I assisted BabcockBorsig Power in Germany to align their German subsidiary Babcock Borsig Power Environment (former L&C SteinmUller) with their U.S. subsidiary DB Riley (today BabcockPower) in Worcester, Massachusetts in orderto take full advantage ofthe business opportunities provided through the NOx SIP call underthe Clean Air Act Amendments (CAAA) Title I Groundlevel Ozone Requirements1

. Three months into the project, I was offered to take overthe environmental business unit of DB Riley, Inc. (later renamed Babcock Borsig Power, Inc., now renamed BabcockPower,· Inc.) in Worcester, Ma. After accepting this position, I was responsible for the SCR retrofits for the coal-fired units ofAmerican Electric Power (AEP), Detroit Edison (DTE), Duke Power, Louisville Gas & Electric (LG&E) and its subsidiaries Kentucky Utilities (KU) and Western Kentucky Energy (WKE), all now consolidated under E.ON-US, Northern Utilities (NU), Pennsylvania Power & Light (PP&L), Santee Cooper (SC), and Wisconsin Electric Energies (WE Energies) as well as the development ofthe emerging markets for FGDs and mercury-removal technologies. I left DB Riley and refocused on E&EC shortly before DB Riley's German parent company declared bankruptcy. Through E&EC I founded SCR-Tech LLC together with a German partner and was acting president ofSCR-Tech between 2001 and 2005. SCR-Tech was dedicated to providing the North American utility industry with SCR management and catalystregeneration services. Afterthe sale ofSCR-Tech in 2004, I left SCR-Tech in 2005 andjoined Steag LLC, a wholly owned subsidiary ofSteag AG in Germany. Steag AG (now renamed Evonik Steag GmbH) is part ofEvonik Industries AG and dedicated to powergeneration and engineering. Evonik Steag GmbH owns and operates more than 10,000 MW ofmostly coal-fired power plants around the world. In 2005, I accepted the position as president ofEvonik Energy Services LLC (formerly Steag LLC), which has been dedicated to serve the North American utility industry with SCR design and management services since 1992 and also with catalyst regeneration services since 2007. Through E&EC, I am also assisting the North American utility industry in their SCR and

1 Call by USEPA for State Implementation Plans in 19 Eastern States in orderto reduce the NOx emissions of large sources (e.g. coal fired power plants) as required by the 1990 Clean Air ActAmendments (CAAA) underTitle I - Groundlevel Ozone. A-7FGD needs by fully utilizing my experience and expertise, which I developedoverthe past 21 years working as an engineer solely in the area ofairpollution control systems for fossil fuel fired power plants and waste incineration facilities with afocus on FGDs and SCRs.



### 4. THE MILTON R. YOUNG STATION: BACKGROUND
The M. R Milton Station consists oftwo North Dakota lignite-fired steam electric generation units, with gross electric generating capacities ofapproximately 257 megawatts electric (MWe) (Unit I) owned by MinnkotaPower Cooperative and 477 MWe (Unit 2) owned by Square Butte Electric Cooperative. The units went into operation in 1970 (Unit 1) and 1977 (Unit 2). Both units feature cyclone-fired Babcock & Wilcox (B&W) boilers followed by tubular airpre-heaters. Airpollution control equipment consi,sts ofoverfire air (OFA) systems forboth units (Unit 2 OFA is scheduled in 2007 and Unit I OFA in 2009), a coldside electrostatic precipitator (ESP) for particulate matter (PM) control for both units and a lime/fly ash wet scrubber for sulfurdioxide (SOz) control for Unit**2~.** Unit I will be retrofitted also with a wet lime scrubber supplied by Marsulex, which is scheduled to commence operation in April 2011.2. Additionally, Minnkota Power Cooperative and Square Butte Electric Cooperative are committed to retrofit BACT for NOx control for both units under a ConsentDecree with the United States and the State ofNorth Dakota, dated July 27, 2006. The NOx control technology to be retrofitted must be determined by a top-down BACT Analysis, which must evaluate various technologies including SCR.



### 5. SCRTECHNOLOGY
The selective catalytic reduction (SCR) technology was originally developed in Japan under a governmentgrant in the 1970s and subsequently retrofitted to most Japanese fossil fuel fired powerplantslQ

. SCR involves injecting gaseous ammonia generated from UREA, aqueous or anhydrous ammonia into the flue gas at a specific temperature before it reaches a catalyst. The catalyst significantly lowers the temperature required to complete the reaction ofthe injected ammonia with NOx (mostly nitrogen oxide NO and nitrogen dioxide NO

### z ) to form nitrogen and water. Therefore the SCRreactor can be operated at a lowertemperature zone at a suitable location in the flue gas path. Compared to the same reactions taking place withoutthe presence ofa catalyst, which is commonly referred to as selective non-catalytic reduction (SNCR) and requires flue gas temperatures between 1,500 F**(~800** DC) and 2000 F

Milton R. Young Station

- OurJewel on the Prairie, brochure published by Minnkota Power Cooperative and Square Butte Electric Cooperative on Minnkota's website: www.minkota.com.
2 McIlvaine Utilitiy E-Alert #868, April 4, 2008.
12 Ando, Jumpei, "S02 and NOxRemoval for Coal Fired Boilers in Japan," presented at the Seventh Symposium on Flue Gas Desulfurization, May, 1992. A-8**(~** 1,100 °C), the SCRprocess allows for a much higherNOx removal efficiency compared to the SNCR process while ensuring a very low (typically less than 2 ppmvd @ 3% 02) ammonia slip. Continuous NOx removal efficiencies ofwell above 90% with NOx outlet concentrations well below 0.05 Ibs/MMBtull have been reportedll

. Various principles ofthe SCRtechnology are commonly described foremost by the SCR reactor's location within the flue gas path. Three main categories ofSCR systems with one being split into two subcategories are known for fossil fuel fired utility boilers, namely: High-dust SCR (HDSCR) located between the boiler's economizeroutletand the air perheater inlet upstream ofthe ESP (pictured below). Atthis location typically no reheating ofthe flue gas is required.

Steam Boiler High-Dust SCR Reactor Flue Gas Oesulfurization

Low-dust SCR (LOSCR), which is split into two subcategories, namely:

o Hot-side LDSCR located downstream ofa hot-side ESP and upstream ofthe airpreheater (notpictured below). Atthis location no reheating ofthe flue gas is typically required as the hot-side ESP is also upstream ofthe air pre-heater.

o Cold-side LDSCR located downstream ofthe air preheater as well as downstream ofa cold-side ESP (pictured below). Atthis location reheating of the flue gas is typically required as the cold-side ESP is downstream ofthe air preheater

.

.!l.. MMBtu = million British thermal units.
II Erickson,

## c., S. Straight, L. Hutcheson, "Coal-Fired SCR Operating Experience with High Removal Efficiency and Low-NOx Firing Systems", BabcockPower's website: www.babcockpower.com. A-9Steam Boiler Steam Coil For Flue Gas Reheating Low-Dust SCR Reactor

Gas/Gas

Heat Exchanger

Tail-end SCR (TESCR) located downstreamofa dry orwet flue gas desulfurization (FGD) system (pictured below). Atthis location the same type and net quantity of reheating ofthe flue gas is always required as in case ofLDSCR located downstream ofa cold-side ESP pictured above.

Steam Boiler Steam Coil For Flue Gas

Reheating Tail-End SCR Reactor

Gas/Gas

Heat Exchanger

### ~~~

Afterthe technology was initially installed in Japan, SCR began to be used in Europe, mainly in Germany during the 1980s, where legislation introduced in 198311 required all power plants to drastically reduce the NOx emissions by the end ofthe decade. As a result, the first HDSCR on a coal-firedpowerplant in Europe went into operation in 1985 (Altbach Power

il EPA-450/3-92-004, Office of Air and Radiation, Office ofAir Quality Planning and Standards, "Summ\lry of NOx Control Technologies andtheirAvailability and Extent ofApplication", February 1992. A-I0Station Unit Sl.±), the first TESCR in Europe went into operation in 1986 (Hamburg Hafen Generating Station Unit 1.li) and the first LDSCR went into operation in 1988 (Walsum Cogeneration Plant Unit 

### 7 lQ). By the end ofthe 1980s, SCRs wereused in a wide variety of coal-fired powerplants worldwide afterAustria, Denmark, Germany, Holland and Japan had retrofitted most oftheir coal fired powerplants with SCR systems forNOx removal. Even the first HDSCR on a lignite or brown coal fired utility boiler went into operation in Austria in 1990 (Voitsberg Power Station Unit J11). By the end ofthe 1980s, well over 100 SCR systems had been installed in Europe on more than 30,000 MW ofcoal fired**~enerating** capacity with most SCRs representing retrofits ofcoal fired generating unitsL**~.** As reported by the Electric Power Research Institute (EPRIio, an institution solely funded by and dedicated to the electric utility industry, by 1989 the SCRtechnology was fully developed in two basic forms, namely as HDSCRs and as TESCRs. It is worth mentioning thatthe TESCR principle was mainly developed for the use on cyclone-fired and otherwet bottom boilers because oftheir very high catalyst deactivation rates resulting from high arsenic levels in the flue gas in case offly ash re-injection into the furnace for internal vitrification and no arsenic mitigation by means oflimestone addition. Furthermore, TESCRs were also applied in some cases due to space constraints and/or difficult retrofit sites where the installation ofa HDSCR would have caused elongated periods ofdowntime ofthe unit. In total about40% ofthe SCR retrofits in Europe were TESCRs. EPRI211reports that all European SCR systems visited during a field trip in 1988 consistently mettheir design removal efficiencies ofup to 88% in HDSCRs and TESCRs operating in coal fired units firing coals with sulfurcontents up to I.S %wt. This overall finding was solidified by 1989 after additional years ofoperating experience. EPRI reported heat rate penalties on the unit between 1 and 3% resulting from the necessity offlue gas reheating in case ofcold-side LDSCR and/or TESCR. Such flue gas reheating requires the use ofa gas/gas heat exchanger, in which the flue gas coming from the SCR

1.1 Fisia Babcock GmbH (formerly L&C SteinmiillerGmbH) and BabcockPower, Inc. reference lists SCR systems
. .li Ibid

l.§ Ibid
11 Reference liston CERAM's website: www.frauenthal.net.
.lli Technical Feasibility and Cost ofSCRNOx Control in Utility Applications, RP 1256-8 prepared by United Engineers and Constructors, Inc. for Electric PowerResearch Institute (EPRI), August 1989.
12 EPA-450/3-92-004, Office ofAir and Radiation, Office ofAir Quality Planning and Standards, "Summary of NOx Control Technologies and theirAvailability and ExtentofApplication", February 1992

. .fQ Technical Feasibility and Cost ofSCRNOx Control in Utility Applications, RP 1256-8 prepared by United Engineers and Constructors, Inc. for Electric PowerResearch Institute (EPRI), August 1989.
l..!. Ibid A- 11reactor outlet is used to reheatthe flue gas going to the SCRreactor inlet similarly to an air preheater. These gas/gas heat exchangers can be designed as rotary type, tubular orplate type heat exchangers. All three types have been utilized successfully. Since a 100% efficient heat transfer from the outgoing to the incoming flue gas is physically impossible, a comparatively small amount ofadditional energy must be provided for reheating the flue gas downstream of the gas/gas heat exchangerto the SCR reactor inlettemperature. This additional energy, whichis needed to overcome the temperature gradient ofthe gas/gas heat exchanger, amounts to an additional heating ofthe flue gas oftypically between 45 degrees F (25 K) and no more than 90 degrees F (50 K) with amounts known as low as 18 degrees F (IO K). Flue gas reheating is most commonly accomplished in one oftwo ways, namely: In case ofcoal-fired powerplants or when steam ofsufficiently high pressure and temperature is available, a steam coil is used for flue gas reheating. The use ofsteam for flue gas reheating is generally the most economical and advantageous method as it neither increases the flue gas flow rate nor adds any additionally constituents (i.e. NOx) to the flue gas. Steam reheating is particularly economically advantageous in coal-fired powerplants, which are "turbine limited" meaning the boiler can generate more high pressure steam at full load than the turbine needs for generating its maximum electrical output. In sucha case, the surplus generated high pressure steam, which cannot be used for generating electricity, is ideally suitable for the use ofsteam reheating ofthe flue gas without or only minimal impact on the generating capacity ofthe unit. In this case, the heat rate penalty ofthe unit may be eliminated entirely. In case no steam oronly steam ofinsufficienttemperature and pressure is available as it is the case in many non-power plant applications, natural gas duct burners are typically used for flue gas reheating. Such flue gas reheating results in some additional operating cost for natural gas, which, however, can at leastpartially be offset by significantly prolonged catalyst life oftypically well over 100,000 SCR operating hours, a smaller overall SCR reactor, less installed catalyst volume and a smaller catalystpitch22• In some cases the additional operating costs can be completely offset by the elimination ofextended unit downtime, which would be necessary for an HDSCR retrofit, and the availability ofexcess high pressure steam, thus making TESCRthe most economical solution. EPRI23 reported TESCR systems in Europe to achieve NOx removal efficiencies between 83 and 92% with cost between US$ 180

- 225 perkW and HDSCR systems to achieve NOx removal efficiencies between 65 and 88% with cost between US$ 65

- 200 per kW. Considering the fact thatthis was reported in 1989, in otherwords more than a decade before the SCRretrofitphase in the U.S. resulting from the

1£ Sobolewski, H, H. Hartenstein, H. Rhein, "STEAG's Long Tenn SCR Catalyst Experience and Cost", The 2005 EPR! Workshop on Selective Catalytic Reduction, Louisville, KY, November2005.
II Technical Feasibility and Cost ofSCRNOx Control in Utility Applications, RP 1256-8 prepared by United Engineers and Constructors, Inc. for Electric PowerResearch Institute (EPR!), August 1989.
A- 12CAAA NOx SIP ca1l24 and considering the fact thatthe cost ofalmost all SCRs retrofitted in North America were within this range, it can be reasonably expected thatthe retrofit cost for TESCR will also fall approximately within the range determined by EPRI back in 1989. All European andNorth American HDSCRs have achieved theirtargeted NOx emission rates without any major operational problems. Early design flaws mostly resulting from inadequate flow conditions and flue gas distribution problems were mostly corrected by about 1990. By early 2000 more than 23,000 MW ofSCRs were in operation in Japan and more than 55,000 MW in Europe25

, ofwhich about 40% are TESCRs. Currently, more than an estimated 250,000 MW ofHDSCRs are successfullyoperating worldwide on utility boilers with an estimated more than 100,000 MW in North America. The balance can be found in Europe (Austria, Belgium, Denmark, Finland, France, Germany, Holland, Italy, Portugal, Spain, Sweden, Turkey, etc,) and Asia (China, Japan, Korea, Taiwan, etc.). By 1989/1990 approximately 18,000 MW ofTESCRs were in operation or near completion on coal-fired utility boilers in Europe. Atthe same time almost four years ofextremely positive operating experience had been collected on the first TESCR, which went into operation in Hamburg in 1986. Today after more than 20 years ofTESCR operating experience, catalyst lifetime in excess of 100,000 is considered normae6

. As a result ofthis extremely positive long term operating experience with TESCR, this principle was generally adopted as a universally applicable SCR solution for all types and compositions offlue gases incompatible for HDSCR due to the catalystdeactivation characteristics. Incompatible conditions for HDSCR can be eitherdue to: physical parameters ofthe flue gas, which are unacceptable, such as temperature, ash content, etc., or chemical composition ofthe flue gas, which may cause uneconomically rapid catalyst deactivation such as higher concentrations ofgaseous arsenic, phosphorus, sodium, potassium, calcium, magnesium, chromium, barium, selenium, etc
.. Consequently, TESCRs were installed for NOx control on a wide variety ofhigh temperature combustion and otherthermal processes including:

Call by USEPA for State Implementation Plans in 19 Eastern States in orderto reduce the NOx emissions of large sources (e.g. coal fired power plants) as required by the 1990 Clean AirActAmendments (CAAA) underTitle I - Groundlevel Ozone. Sanyal, A., W. Allison, "Lessons Learned from SCR Experience ofCoal-Fired Units in Japan, Europe and USA; Are These Enough?" Presented atthe 2002 DOE Conference Selective Catalytic Reduction and Non Catalytic Reduction forNOx Control, Pittsburgh, PA, May 2002

. .fQ Sobolewski, H, H. Hartenstein, H. Rhein, "STEAG's Long Term SCR CatalystExperience and Cost", The 2005 EPRI Workshop on Selective Catalytic Reduction, Louisville, KY, November 2005. 

### A-13municipal solid waste incinerators (1989) hazardous waste incinerators (1990) sewage sludge incinerators (1990) hospital and medical waste incinerators (1990)

. crematories (1991) pharmaceutical waste incinerators (1992) refinery crackers (1994) glass smelters (1994) blast furnace and coke gas combustors (1994) nitric acid plants (1994) biomass furnaces (1994) construction debris and waste wood combustors (1995) electric arc furnaces (1996) ammunition and chemical weapons incinerators (1997) ethylene crackers (1997) Orimulsion boilers (1999) roller mills (2000) photovoltaic cell production (2002) hydrogen reformers (2003) steel coil heattreatment facilities (2003) sintering plants (2003) steel pickling (2005) In short, almost every high NOx producing process imaginable was successfully retrofitted with TESCR systems making the SCRtechnology the most widely used secondary NOx A- 14reduction technology worldwide. As a matter offact, in many cases, HDSCRs or LDSCRs were successfully installed and operated despite the fact that original pilottesting often suggested severe, rapid catalystdeactivation and seriously questioned the technical feasibility ofeitherone ofthese two SCRprinciples for these applications. Examples include: lignite or brown coal fired boilers (HDSCR, 1990) cyclone fired and other wet bottom boilers with fly ash re-injection (HDSCR, 1991) heavy fuel oil (HDSCR, 1992) municipal solid waste incinerators (LDSCR, 1992) hazardous waste incinerators (LDSCR, 1995) roller mills (LDSCR, 2000)
cement kilns (HDSCR, 2003) biomass (HDSCR, 2006) Two o'fthe most recent examples ofthis development in the U.S. are the ongoing HDSCR retrofits on PRB-fired utility boilers as well as at several utility boilers firing Texas lignite. Once again, initial pilottesting seemedto have suggested thatcatalyst deactivation through fly ash pluggage and chemical poisoning may be too rapid to make HDSCR economically viable. Forexample, in case ofPRB-fired utility boilers, HDSCR pilottesting conducted at

.Dynegy's Baldwin Energy Center (Baldwin PilotTesting) yielded results thatclearly

suggested that PRB caused "significant accumulations ofash on the catalyst, on both macroscopic and microscopic levels. On a macroscopic level, there were significant observable accumulations that plugged the entrance as well as the exit ofthe catalyst sections. On a microscopic level, the ash materials filled pores in the catalyst and, in many cases, completely maskedthe pores within 4 months27." During HDSCRpilottesting atLuminant's Sandow Generating Station Unit4 catalyst deactivation was determined to be about 20% after approximately 2,900 hours before increasing to approximately 50% after some 3,500 hours due to catalyst**pluggin~.** Based on an extrapolation ofthis data a HDSCR would not likely have reached 10,000 operating hours priorto catalyst needed to be added or exchanged. Forcomparison purposes, typical SCR catalystdesign requires an addition or exchange ofcatalyst during an outage when the total

21. Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalyst performance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005. Smith, R, J. Bennett, D. Broske, "Impacts ofTexas Lignite on SCR Catalyst Life and Performance", presented at the 2007 EPRI SCR Workshop in Pensacola, Florida, November 2007. A- 15reactorpotential has reached between 60% and 75% ofthe original value when equipped with all new catalyst. Yet, in both cases, at Baldwin and Sandow, HDSCR has become the NOx control method of choice. Currently, more than fifty (50) PRB-fired boilers including at leasttwenty two (22) cyclone-fired units have successfully operated HDSCRs without any ofthe problems suggested based on the Baldwin Pilot Testing results29

.Likewise, HDSCRs are being installed at several utility units burning Texas lignite including Oak Grove 1 & 230, Sandow 411 & 532
, Martin Lake 1,2 & 333 and Limestone 334

. In case ofa TESCR installation, the situation is dramatically less challenging resulting from the fact that the flue gas downstream ofa wet scrubber, which a TESCR is exposed to, is extremely clean compared to whatthe catalyst is exposed to in a HDCSR upstream ofthe ESP. Downstream ofan ESP and a wetscrubber in excess of99% ofthe fly ash is removed in the ESP35 and between 90% and 95% ofS02 is removed in the wet**scrubbe~,** thus leaving very little ifanything in the flue gas that is critical for catalyst deactivation. Additionally, downstream ofa wet scrubber, the flue gas has gone through its dew point after being cooledto saturation while passing through the wet scrubber. Going through the dew point ofthe flue gas, which is typically between 110 F**(~43** °C) and 150 F**(~65°C),** means that all condensable catalystpoisons such as alkali and earth alkali salts, arsenic and phosphorus oxides will inevitably have condensed and, along with all other highly water soluble gaseous catalystpoisons including sodium and potassium sulfates, phosphates and carbonates, willhave been mostly removed by the wet scrubber. In a wet scrubber all water soluble compounds including water soluble alkali sulfates, phosphates and carbonates as well

. as all residual alkali vapors are virtually quantitatively removed as a result oftheir extremely

high water solubility. The very small residual amounts (less than 1%) ofsmall particles 

## « 5 /lm) passing through the ESP consist ofcondensed vapors or aerosols including sulfuric acid, alkali sulfates, earth22 Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalystperformance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005.
JQ E-Mail from Randy Sadleron behalfofCindy Khalaf, PresidentofArgillon LLC, supplier ofthe SCR catalyst for Oak Grove 1 & 2, dated June 24, 2008.
11 McIlvaine Utiltiy E-Alert#870 dated April 18, 2008. Jones, B., Introductory presentation at the GulfCoast Power Association Spring Conference, April 2006.
Jl McIlvaine Utiltiy E-Alert#874 dated May 16,2008.
11 McIlvaine Utility E-Alert#871 dated April 25, 2008.
J2 Milton R. Young Station

- OurJewel on the Prairie, brochure published by MinnkotaPower Cooperative and Square Butte Electric Cooperative onMinnkota's website: www.minkota.com.
JQ Ibid A- 16alkaline oxides and silicates. These small particles often act as condensation nuclei during the rapid flue gas quenching in the inletofthe wet scrubber and are largely removed by this mechanism. Thus, their already small quantity downstream ofthe ESP is reduced further, typically by at least 50% across a wet scrubber. This means that compared to a HDSCR, catalyst installed in a TESCR is confronted with less than 0.5% ofthe particulate matter and less than 5 - 10% ofthe acid gases, vapors and other water soluble compounds, which cause catalyst deactivation. Consequently, the experienced catalyst deactivation rate is correspondingly slower. It must be noted that particle bound compounds add very little to the chemical catalyst poisoning causing deactivation. Only gaseous compounds or in liquid dissociated ions of salts ofthese compounds are chemical catalyst poisons. However, as explained earlier, these gaseous compounds are largely removed in a wet scrubber and the remaining concentrations downstream ofa wet scrubber are typically so negligible thatthe result is and in extraordinarily slow catalyst deactivation. Furthermore, the flue gas is being reheated in a TESCRpriorto entering the catalyst, which means thatthese very small residual concentrations ofchemical catalystpoisons including alkali and earth alkali sulfates and phosphates as well as the flue gas itselfare at least400 degrees (200 K) above their respective dew points, which virtually eliminates the possibility ofthese residual catalyst poisons condensing in the pores ofthe catalyst. 

### In general, the condensation temperature or dew point ofany compound including these gaseous catalyst poisons is a function ofthe flue gas temperature and the compound's concentration in the flue gas. As noted above, the residual concentrations ofcatalyst poisons are very small in a TESCR downstream ofa wet scrubber and the difference between their dew pointtemperature, which is the flue gas temperature atthe outlet ofthe wet scrubber and the TESCR operating temperature is very large due to the reheating ofthe flue gas. Consequently, any type penetration ofthese chemical catalyst poisons and subsequentcondensation in the catalystpores is at least extremely unlikely ifnot physically impossible atthe TESCR operating conditions. The virtually negligible residual amount ofgaseous catalystpoisons entering a TESCR compared to an HDSCR results directly in an almost proportionally extended catalyst life. Based on 20 years ofextraordinarily successful full scale TESCR operating experience in Europe, a catalyst life oftypically well more than 100,000 hours mustbe consideredthe norm ratherthan the exception. Several TESCRs after wet bottom utility boilers are still in operation after 20 years with the initial fill ofcatalyst and no replacement, exchange or addition37• Additionally, the minimal concentration ofcatalystpoisons entering a TESCR and the resulting very slow long-term catalyst deactivation (as experienced over 20 years of operation ofTESCRs) ledto the reduction in operating temperatures for TESCRs as shown in the graph below, which can be found on Argillon's website38•Argillon, who is one ofthe

TI Sobolewski, H, H. Hartenstein, H. Rhein, "STEAG's Long Term SCR Catalyst Experience and Cost", The 2005 EPRI Workshop on Selective Catalytic Reduction, Louisville, KY, November 2005.
1J! Argillon's website: www.argillon.com. A- 17leading catalyst manufacturers ofhoneycomb as well as plate catalystmarketed underthe trade name SINOx, has a wealth ofexperience in all types ofSCR applications (HDSCR, LDSCR, TESCR) with more than 500 SCR installations worldwidel2.. Based on Argillon's extensive experience, Argillon promotes the use ofTESCR in a temperature range between approximately 300 F**(~150** °C) and no more than about 570 F (300°C) as can be seen in the graph below.

SlNOxe Hi9tl**Temperatu~'** 

## catalYst**.~~am.cenQt"ator** oVieI'PIMtS standard**SINO~** CatalySt L._--,-:"-'-

..**-~,7-:'.-,-:-,--'--~** __.--_."._--_._._--_.

__.__."'._

...0

__..0

...._. •

__.__. . _ i

..... . 

# I**S'N~~~ I~rn~~**  !.' '" Catalyst I.

. ... I I

# r 1 I i

# I I i 

### i 

# r i i I I ! 

### I I I i 

### i'. ··.. i •• };;.:**iTailel')~;** I ' ........•..... 

### 'Plants 

## !

.... ;;.!.;

.. 

### 200"C 350*C 

### Operating Temperature
As a matter offact, for purely economic reasons and regardless ofthe fuel burned, no TESCR system in Europe operates today at a temperature greaterthan about 550 F**(~290** °C). Today, the majority ofTESCRs behindplants such as municipal and hazardous waste incinerators, which have an incomparably greaterfuel variability and much higher concentrations ofthe entire spectrum ofcatalystpoisons (arsenic, barium, calcium, chromium, magnesium, phosphorus, potassium, selenium, sodium, thallium, etc.) than any coal-fired boiler will ever have, operate downstream ofwet scrubbers and/orbaghouses or activated carbon reactors (ACR) attemperatures as low as 300 F**(~150** °C). These low temperature TESCR operations have been extremely successful for over a decade now with minimal to no catalyst deactivation experienced. CERAM is another leading manufacturer ofhoneycomb SCR catalyst and with well over 500 SCR installations worldwide, more than 100 ofwhich are LDSCR and TESCR installations. CERAM, arguably one ofthe most experienced suppliers ofTESCRcatalyst, fully confirms this concept oflowering the TESCRtemperature. CERAM sees no need for a TESCR operating temperatureofmore than about 554 F (290°C) even in case ofa wet bottom boiler

J2 Argillon's website: www.argillon.com A- 18such as a cyclone fired unit burning the most complex and difficult fuels including North Dakota lignite4o

. As a matter offact, the only thing that dictates the minimum SCR operating temperature are the residualS02 and S03 concentrations in the flue gas, which determine the ABS reaction equilibrium±l and thus the probability for ABS deposition on the catalyst and in the gas/gas heat exchanger. This, however, is not an irreversible catalyst poisoning issue but rather a reversible fouling problem not related to the SCRcatalyst per se but simply to the reaction chemistry between H20, S03 and NH3 in the flue gas at various temperatures. In summary it can be stated thatthe SCRtechnology is the most widely used secondary NOx control technology in the world. It is technically feasible and applicable to a large number of thermal processes including all types ofutility boilers burning any kind offuel. In my professional experience gained overthe last 20 years with the SCRtechnology, neitherthe design ofthe boileror the combustion system nor the composition ofthe fuel burned has ever posed an irresolvable technical obstacle, which made the application ofthe SCRtechnology in one ofits principles (HDCSR, LDSCR, TESCR) technically infeasible. The only challenge is the proper selection ofthe appropriate type ofSCRprinciples (HDSCR, LDSCR or TESCR) and the correct SCR process and catalyst design. This selection, however, is neither a question oftechnical feasibility or applicability nor ofavailability ofthe SCRtechnology but simply a question ofeconomics.



### 6. SCREVALUATION
In June 2008, the North Dakota Department ofHealth's Division ofAir Quality issued a "Preliminary BestAvailable Control Technology Determination for Control ofNitrogen Oxides for M.R. Young Station Units 1 and 242", in which itdetermined "that SCR is not technically feasible for North Dakota lignite-fired cyclone boilers." This determination seems to rest largely on five documents provided by Minnkota Power, namely: 1. Minnkota's Best Available Control Technology Analysis Study for Milton R. Young Station Unit 1, October 2006.43 

### 2. Square Butte's Best Available Control Technology Analysis Study for Milton R.

iQ Personal conversation with John Cochran, PresidentofCERAM Environmental, Inc., on June 25, 2008.
11 The reaction equilibrium between ammonium sulfate «NH4)ZS04) and ammonium hydrogen sulfate (Nf!tHS04 ), which is often incorrectly referred to as ammonium bisulfate orABS, in the flue gas. Both, ammonium sulfate and ammonium hydrogen sulfate are products ofthe inevitable reaction ofgaseous sulfur trioxide (S03) and ammonia (NH3 ) contained in the flue gas upstream ofthe SCRcatalyst. Preliminary Best Available Control Technology Determination for Control ofNitrogen Oxides for M.R. Young Station Units 1 and 2, Division ofAir Quality, North DakotaDepartment ofHealth, 918 East Divide Avenue, Bismarck, North Dakota.
1J. NOx Best Available Control Technology Analysis Study for Milton R. Young Station Unit 1 Minnkota PowerCooperative, Inc., Revised Final Report, October 2006,311777. A- 19Young Station Unit 2, October 2006.44 3. SCR Catalyst Performance in Flue Gases Derived From Subbituminous and Lignite Coals, A. Benson, et al.45 4. Application ofSCRTechnology to North Dakota Lignite Fuels, PowerPoint Presentation slides by Sargent and Lundy, LLC, May 2007.46 5. Additional Information and Discussion ofVendor Responses on SCRTechnical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 and 2, May 2008.47 These five documents are seemingly reasonably recent with the first and second document dated October 2006 and the forth and fifth documents dated May 2007 and May 2008, respectively. However, the third document even though published in 2005 was already accepted for publication in mid 2004 and the actual HDSCR catalystpilottesting atthe Coyote Station (Coyote Pilot Testing) and atthe Baldwin Energy Center (Baldwin Pilot Testing) that lasted at least 6 months at each plantwas conducted as early as 2000/2001 48

. This is relevant, since the Coyote Pilot Testing, which was conducted following the Baldwin Pilot Testing, used the same pilottest reactorequipped with the same Haldor Topsoe catalyst that was used atthe Baldwin Pilot**Testin~.** Based on the Baldwin Pilot Test results the technical feasibility ofHDSCR at Baldwin's cyclone-fired Units 1 & 2 burning 100% PRB would have been at least highly questionable and a BACT determination similarly conducted as the one by the Department for the M.R. Young Station would most likely have reached the same conclusion as was reached for the M.R. Young Station, namely thatthe SCR is technically infeasible for retrofit atthe Baldwin Energy Center. However, the full scale HDSCRs at Baldwin Units 1 & 2 were commissioned in 2002 and 2003 and have since been in service for more than 45,000 hours without any ofthe problems indicated during the Baldwin Pilot Testing.

11 NOx Best Available Control Technology Analysis Study for Milton R. Young Station Unit 2 Minnkota PowerCooperative, Inc. Operating Agent for Square Butte Electric Cooperative, Owner. Revised Final Report, October2006, 311777. Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalyst performance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005. Sargent and Lundy, LLC, "Application ofSCRTechnology to North DakotaLignite Fuels", a Power Point presentation, May 2007.
11 MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendorResponses on SCR Technical Feasibility, North Dakota's NOx BACT Determination forMilton R. Young Station Units 1 & 2", May 8, 2008. E-mail from Flemming Hansen (Haldor Topsoe) dated June 30, 2008. Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalyst performance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005. A-20At Associated Electric's New Madrid Station Units 1 & 2, both cyclone-fired units burning 100% PRB, HDSCRs were commissioned in 1999/2000 already and have been in operation successfully since then. Numerous other cyclone-fired units burning 100% PRB were retrofitted with HDSCRs and have also been operating successfully2Q,.21. This clearly proves thatthe results obtained during the Baldwin Pilot Testing with this particular SCR catalyst and this particularpilot test reactor design cannot be considered representative for a full scale HDSCR installation atthe same u.nit. Baldwin Units 1 & 2 don't use tIie type ofHaldor Topsoe catalyst used in the Baldwin and Coyote PilotTesting but instead use Argillon plate catalyst. New Madrid Units 1 & 2 also don't use the type ofHaldor Topsoe catalyst used in the Baldwin and Coyote Pilot Testing but instead use Cormetech honeycomb catalyst. Also, the HDSCR reactors at Baldwin andNew Madrid were properly designed and are adequate to meetthe challenges ofthis application and not as ill-designed and fundamentally flawed as the Baldwin and Coyote Pilot Testing reactor and catalyst design. This fact along with the conclusion that the Coyote Pilot**Testin~** 9idn't provide much useful data was pointed out clearly by the Department. Furthermore, CERAM in one oftheir responses explicitly stated their beliefthat**"t~e** information and test work presented indicate that it is certainly premature to assume that there is afatal flaw for the use ofhigh duct SCR behind cyclones burning North Dakota lignite. The concerns presented are similar in argumentto those that where used 10 years ago againstthe application ofPRB for high dust (SCR) applications53". CERAM continues stating that "concerns reported by Dr. Benson54 regarding high sodium contents and fine fume are duly noted, but inadequate evidence is presented thatthis could be a fatal flaw to application of(HD)SCR considering the flawed pitch and resultantpluggage ofthe (Haldor Topsoe) catalyst (used) during (the) Coyote Station**testin~".** This view ofCERAM was further discussed in a personal conversation with Mr. Kurt Orehovsky, Product Manager of

2Q NOx Best Available Control Technology Analysis Study for Milton R. Young Station Unit 1 Minnkota PowerCooperative, Inc., Revised Final Report, October 2006, 311777

. .2l NOx BestAvailable Control Technology Analysis Study for Milton R. Young Station Unit 2 Minnkota PowerCooperative, Inc. Operating Agent for Square Butte Electric Cooperative, Owner. Revised Final Report, October2006, 311777.
g Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalyst performance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005.
21 MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendorResponses on SCR Technical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 & 2", May 8,2008.
2± Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalyst performance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005.
i2. Minnkota Power Cooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendor Responses on SCR Technical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 & 2", May 8,2008.
A- 21CERAM's SCR Catalyst Division56• Mr. Orehovsky clearly statedthat CERAM reviewed all available data carefully andthoroughly and sees currently no reason why HDSCR would be technically infeasible at M.R. Young Station, however, only after resolving the temperature variation problem. He pointed outthat CERAM would not expect any extraordinarily high catalyst deactivation orpluggage at a cyclone-fired unit burning North Dakota lignite ifin fact an HDSCR system would be properly designed and operated. CERAM's extensive experience with lignite and biomass fired units equipped with HDSCR supportthis position. Despite that clear statement and despite the ongoing proofin form ofthe success ofthe HDSCRs atNew Madrid, Baldwin and many other cyclone-fired units burning 100% PRB, the only field datathe Department relied upon concerning the expected catalyst deactivation and pluggage ofan HDCSR installed at M.R. Young Units I and 2 is the data obtained from the ill-designed and fundamentally flawed Coyote Pilot Testing. Admittedly, the Coyote PilotTesting results seem to indicate worse pluggage than the Baldwin Pilot Testing results. However, it must be noted thatthe same pilottestreactor and the same catalyst, which had been already used (and plugged) at Baldwin was subsequently used at Coyote. The well known fact that catalystthat had been plugged and only mechanically cleaned is more likely to quickly plug again than new, unused catalyst was simply ignored. Furthermore, it is more than reasonable to expect that lignite fired units will cause a higherrate ofcatalyst deactivation in an HDSCRthan a PRB fired unit. This fact was also proven during the Sandow 4 pilottesting2Z but is no reason for considering the SCR technology in general as technically infeasible. In case ofSandow 4 and other units burning Texas lignite HDSCR was even consideredto be more economically viable than LDSCR or TESCR with the technical feasibility noteven being a question. Given the fact thatthe same pilottestreactor and catalystwere used for the Baldwin and subsequently for the Coyote Pilot Testing, it can be clearly statedthatthe reason for the pilot testing results at Coyote being worse than atBaldwin was because ofthe pilottest reactor and catalyst designs and the execution ofthe pilottesting, all ofwhich were already inadequate for the Baldwin application but disastrous for the Coyote application. Yet, the unanswered question remains, why is it unreasonable to assume that a properly designed and operated HDSCR at M.R. Young Units I and 2 could be as successful as it has been and continues to be atNew Madrid, Baldwin and the many other cyclone-fired units burning 100% PRB despite the fact thatthe results ofthe Baldwin PilotTesting seemed to indicate the exact opposite? Based on this clear and indisputable evidence would not every reasonable engineer first suspectthatthe reason for the failure ofthe Coyote Pilot Testing was the illdesigned testpilotreactor and catalystand the flawed execution ofthe pilottestingjust as it was the case at Baldwin? However, instead oftrying to answerthese most important questions objectively and correctly, the Departmentjumpedto the highly premature and speculative conclusion thatthe SCRtechnology regardless ofthe selectedprinciple (HDSCR,

Personal conversation with Mr. Kurt Orehovsky in Vienna, Austria, on July 7, 2008.
:il. Smith, R, J. Bennett, D. Broske, "Impacts ofTexas Lignite on SCRCatalystLife and Performance", presented atthe 2007 EPRI SCRWorkshop in Pensacola, Florida, November 2007. A-22LDSCR orTESCR) cannotbe applied successful atthe M.R. Young Station. The Department lists the following twelve (12) conclusions that result in the Department's largely speculative and unsubstantiated determination "thathigh dust SCR is nottechnically feasible atthis time for both units atthe M.R. Young Station", the validity ofwhich are discussed in detail in the following sections.


### 6.1 Variability ofFuel Composition _Lignite from the Center Mine is highly variable in heat and ash contents and in the constituents that make up ash, which will affect SCR design and operation. This is an undisputed fact, however, not only true for lignite from the Center Mine but for all coals regardless whether it is anthracite, bituminous, sub-bituminous, lignite, brown coal etc. As a matter offact, these listed classifications are nothing butthe result ofthe extremely high variability ofthe various types ofcoal. Each class in itselfhas a high variability again, which unquestionably affects SCRdesign and operation. This high variability includes also the compounds sodium and potassium (as further discussed in several subsequent sections) as well as all other catalystpoisons. Bituminous and sub-bituminous coals, which are considered relatively unproblematic for HDSCR design and operation, may serve as an example for this typical variability. Bituminous and sub-bituminous coal-fired boilers constitute the vast majority ofHDSCRs in the world even though the: The heating value ranges from less than 8,000 Btu/lb to more than 13,000 Btu/lb. The ash content can vary by one order ofmagnitude from as low as 4 %wt. to as high as 40 %wt. Sulfur contents also vary easily by one order ofmagnitude from less than 0.5%wt. in sub-bituminous to more than 5%wt in bituminous coal. Likewise arsenic contentrange over an orderofmagnitude from less than 3 ppm to more than 40 ppm. The list ofsimilarly wide ranges ofconcentrations and/or variability for individual constituents ofbituminous and sub-bituminous coals could be extended for almost every element ofthe Periodic Table. However, I am not aware ofone single case where this high variability ofthe heat and ash contents ofthe coals and/or ofthe constituents that make up the ash precluded one ofthe principles ofthe SCRtechnology (HDSCR, LDSCR, TESCR) from being technically feasible and applicable. Thus, it remains unexplained why the Department's conclusion that "lignite from the Center Mine is extremely variable in heat content, ash content and in the constituents that make up the ash", leads to the determination thatthe SCRtechnology is not technically feasible. Even though the statementthat "this variability will affectthe design and operation ofan SCR
A- 23system", is only correctwith respectto a HDSCRand maybe partially to a LDSCR, it is most definitely notplausible for a TESCR. In case ofTESCRthe preceding airpollution control equipment (ESP and wet FGD) as well as the flue gas reheating system ofa TESCR, which typically includes a gas-gas heat exchanger and steam coil upstream ofthe SCRreactor, virtually eliminate even the most extreme variability in the fuel and its resulting flue gas composition upstream ofthe SCRcatalyst. It is intuitively obvious that the coal's variability in heat and ash content and in the constituents that make up the ash is no longer ofany relevance in case ofa TESCR system after more than 99% ofthe ash has been removed in the upstream airpollution control equipment 58• 

### 6.2 Results ofthe Coyote Pilot Testing
The Departmentcorrectly states that "the only pilottesting that has ever beenconducted on a unit firing North Dakota lignite was at the Coyote Station59• The pilot scale SCR was plugged after 2 months and little useful data was obtained". The Department further alludes to the fact that "the pilottesting at the Coyote Station did notprovide much useful data, and in hind-sight, was ill-designed for a unit combustingNorth Dakota lignite". Yet despite the Department's indisputably correct and valid recognition ofthis as well as the facts that:

no deactivation data exists and no conclusions should be drawn from this ill-designed and highly flawed Coyote Pilot Testing; several SCRequipment suppliers (Alstom, Babcock Power) clearly stated that, an "(HD)SCR system could be successfully utilized on a boiler fired with Northern lignite,,6o; several catalyst manufacturers (CERAM, HaldorTopsoe) clearly stated and that concerns reported by Dr. Benson2.l regarding high sodium contents and fine fume are duly noted, but inadequate evidence is presented thatthis could be a fatal flaw to application ofSCR considering the flawed pitch and resultantpluggage ofthe (Haldor Topsoe) catalyst during Coyote Stationtesting,,62;
Milton R. Young Station

- OurJewel on the Prairie, brochure published by MinnkotaPower Cooperative and Square ButteElectric Cooperative on Minnkota's website: www.minkota.com.
l2 Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalyst performance in flue gas derived from subbituminous and lignite coals", FuelProcessing Technology 86 (2005) pages 577

- 613,2005

. .§Q MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, "AdditionalInformation and Discussion ofVendorResponses on SCR Technical Feasibility, North Dakota's NOx BACTDetermination forMilton R. Young Station Units 1 & 2", May 8, 2008.
§l Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalystperformance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005.
g MinnkotaPowerCooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendorResponseson SCR Technical Feasibility, North Dakota's NOx BACTDetermination 

### A-24several catalyst manufacturers (CERAM, Haldor Topsoe), who have experience with high sodium and potassium containing fuels, offered industry standard type catalyst performance guarantees (NOx removal efficiency, S02/S03 conversion rate, pressure drop, NH3 slip, catalyst lifetime)63; the Department still concludes that "the Coyote testing demonstrates to the Departmentthat North Dakota lignite firing will have more severe effects (plugging and catalyst deactivation) than units firing sub-bituminous coal when the same design is employed". This statement promotes three basic questions, namely:

a. How can the Coyote Pilot Testing demonstrate to the DepartmentthatNorth Dakota lignite firing will have more severe effects (plugging and catalystdeactivation) when no catalyst deactivation data exists and the pilot scale SCR reactor atthe Coyote Station plugged very quickly because the reactor was ill-designed and the selected catalyst design not suitable, particularly for a unit combusting North Dakota lignite? b. Does the Department have any additional information that may substantiate the Department's otherwise completely unfounded conclusion and that wasn'tprovided to the contacted vendors including Alstom, Babcock Power, CERAM and Haldor Topsoe so thatthey reached the essentially opposite conclusion?

c. Why does the Department imply thatthe same catalyst and SCRdesign employed for units firing sub-bituminous coal must also be used for M.R. Young Station? As pointed out earlier, this is relevant since in the early 2000s, when the Coyote Pilot TestingM was conducted, the results ofwhich provide the only catalystrelevantfield data for the Department's conclusion concerning the rapid pluggage and deactivation ofcatalyst in a HDSCR, no long term full scale HDCSR operating experience was available from Associated Electric's New Madrid Station, which was the first one to install HDSCR on a cyclone-fired unit burning PRB. Yet, as pointed out by Bums & McDonnell, today a significant number ofcyclone-fired units in the U.S. burning PRB successfully operate HDSCRs65, QQ, 67.

for Milton R. Young Station Units 1 & 2", May 8, 2008.
2l Ibid

§± Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalyst performance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005. NOx Best Available Control Technology Analysis Study for Milton R. Young Station Unit I Minnkota Power Cooperative, Inc., Revised Final Report, October 2006, 311777.
§§ NOx Best Available Control Technology Analysis Study for Milton R. Young Station Unit 2 Minnkota PowerCooperative, Inc. Operating Agent for Square Butte Electric Cooperative, Owner. Revised Final Report, October 2006, 311777. A- 25The Department further states that "besides catalyst deactivation, it is likely that a high-dust SCRwould experience plugging problems (deposition on the catalyst surface) due primarily to the carryover ofpopcorn ash from the boiler". This statement is also quite puzzling, since the formation ofpopcorn ash is a commonly known phenomenon that has first caused catalyst pluggage in Germany inthe mid 1990s68 and is also a well known problem in the U.S. since the early 2000s. However, it has been solved successfulll9 by the use ofproperly designed popcorn ash removal systems70. The Department's statementthat "the advances made in the last few years for controlling popcorn ash are not shown to be applicable to a cyclone boilerburning North Dakota lignite" is not only purely speculative but defies all common engineering sense. Various designs and types ofpopcorn ash screens have been installed in a wide variety ofunits in the U.S. and are operating successfully. I believe that no engineering company with SCR experience including Sargent and Lundy and Burns & McDonnell would seriously argue the fact that properly designed popcorn ash screens couldbe successfully installed atM.R. Young Station's Units 1 and 2 without additional pilot scale testing. Needless to addthat in case ofa LDSCR orTESCR any concern overpopcorn ash would be considered absurd simply by virtue ofthe location ofthe LDSCR orTESCR in the flue gas path downstream ofthe ESP (LSDCR) and wet scrubber (TESCR). Furthermore, the Department's statementthat "operation ofan SCR system for only 2 months between catalystreplacements is not considered successful operation ofSCR technology," implies thatthe catalyst in a properly designed full scale HDSCR atthe M.R. Young Station would have to be replaced every two (2) months. Again, no deactivation data was everdetermined during or afterthe Coyote Pilot Testing to substantiate this claim. This forces the conclusion thatthe mostly useless data obtained from the ill-designed and flawed Coyote Pilot Testing was improperly and incorrectly used by the Departmentto speculatively extrapolate to what mayor may not happen in aproperly designed HDSCR system. This bold speculative extrapolation to a catalyst life ofonly two (2) months between replacements in a full scale HDSCR is particularly interesting since the Department immediately contradicts its own conclusion by postulating that "withoutpilottesting, the life ofthe catalyst cannot be predicted with any reasonable certainty." Assuming this latter statementis true and further reiterating the fact that no deactivation testing from pilottesting

fil Sargentand Lundy, LLC, "Application ofSCR Technology to North DakotaLignite Fuels", a PowerPoint presentation, May 2007.
2!! Hartenstein, H., H. Gutberlet, L. Licata, "Utility Experience with SCR in Gennany", a paperpresented atthe Sixteenth Annual International Pittsburgh Coal Conference, October 1999.
22 Sargentand Lundy, LLC, "Application ofSCRTechnology to North DakotaLignite Fuels", a PowerPoint Presentation, May 2007.
1Q Martin, M., M. Harrell, J, Jancauskas, H. Hartenstein, H. Sobolewski, "Large Particel Ash (LPA) Screen Retrofits at Coal-Fired Units in Indiana and Ohio", DOE-NETL Conference on SCR/SNCR, 2006. A-26is available, how can the Department assertthat a properly designed full scale HDSCR system would operate for only two (2) months between catalystreplacements while stating at the same time that the life ofthe catalystcannot be predicted without further pilottesting? Furthermore, the Department's bold postulation ofan expected catalyst life ofonly two (2) months between replacements is made despite the fact thattwo (2) experienced catalyst suppliers (Haldor Topsoe and CERAM) offered firm performance and lifetime guaranteesll for their catalyst installed in an HDSCR ofconsiderably more than the 10,000 hourthreshold arbitrarily defined by the Department. Why the Department ignores all these facts and concludes that it can predictthe expected catalyst life betterthan even the most experienced catalyst manufactures remains unknown.


### 6.3 Soluble Sodium
The Department concludes that "the combustion of(North Dakota) lignite produces soluble sodium compounds, which cause more severe catalyst deactivation than insoluble sodium compounds". Even though this statementmay be generally correct, it remains unclear and unexplained, why soluble sodium compounds, which can only penetrate into the catalyst and deactivate the catalytically active vanadium pentoxide (V20S) when in they are either in the gas phase or as sodium ions (Na+) dissociated in a liquid, would be present in the gas phase or in a liquid and therefore in a mobile form. The argument raised by Minnkota and reiterated by the Departmentthatthe formation oflow temperature sodium-calcium-magnesium sulfates and phosphates poses the most significant problem for the successful operation ofSCRcatalysts in a HDSCR may be true with respect to catalyst deactivation. However, the simple comparison ofemission rates ofthese compounds with the fly ash is not a correct and appropriate way to derive any meaningful prediction concerning the expected catalyst deactivation. Even though the Department correctly states that "the catalyst deactivation rate may not be directly proportional to the emission rates ofthe various constituents", incorrectly continues that "it does provide a means ofcomparison ofthe flue gas characteristics". Unfortunately, the Departmentfails to realize what was pointed out by one ofthe mostexperienced catalyst suppliers, namely that "sodium is not apoison to catalyst at SCR operating temperatures72." Thus, the elaborate comparison ofemission factors ofsodium, potassium, calcium and magnesium emission factors with the fly ash may have some academic value but is effectively meaningless for the correctprediction ofcatalyst deactivation, since particle bound sodium, potassium, calcium and magnesium in the fly ash are not mobile and therefore are not catalystpoisons. Typically, sodium and potassium sulfates, so called pyrosulfate compounds, have very high

II Minnkota Power Cooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendorResponses on SCRTechnical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 & 2", May 8, 2008.
J1 Ibid A-27boiling points well above any possible SCR operating temperature. Thus, it is highly unlikely that any appreciable quantities ofthese pyrosulfates will be present in the SCR in the gas phase. This, however, would be necessary in orderto cause severe and rapid catalyst deactivation. Therefore, underthese conditions these compounds are not a major concern. Alternatively, these pyrosulfate compounds would have to be present in a liquid so thattheir dissociated ions (i.e. Na+, K+) would be mobile in orderto enterthe catalystpores and react with the catalyst's active sites. However, these compounds will only be present in the catalyst in a liquid form ifeitherthe SCR operating temperature is too low orduring shut down when cooling the SCR reactorto temperatures below the moisture dew point. Since the melting point ofmostpyrosulfates is well above the typical HDSCR operating temperature of 650

- 750 F(343

- 400°C) the intrusion ofliquid pyrosulfates is no major concern with respectto a severe, rapid catalyst deactivation. Therefore, even catalyst suppliers state clearly that "sodium is not apoison to catalyst at SCR operating temperatures. Significant deactivation can occur ifcondensed moisture transports sodium residing atthe surface into the catalyst pore structure during outage or layup73". Since the HDSCR operating temperature must be expected to be maintained at well above 650 F (343°C) at all times, no liquid ever occurs during SCR operation not even in the innerpores as the temperature is too high even for capillary condensation. This well known fact is one ofthe main reasons why HDSCR operating temperatures are selectedto be typically in the range between 600 F (315 °C) and 800 F (427°C). Maintaining the required minimum SCR operating temperature at all times is an absolute requirement for all HDSCRs regardless offuel type and/or boiler/burner configuration and has nothing to do with North Dakota lignite and/orcyclone-fired boilers. As pointed out earlier, the condensation ofmoisture in the pores ofthe SCRcatalysttypically occurs only during shut-down and subsequent cooling ofan SCRreactor. Thus, reducing the number ofshut-downs, which result in cooling the SCRcatalystto below the moisture dewpoint, is always advantageous for all HDSCRs regardless offuel- and/or firing type. Given the fact that sixty (60) start-ups were reported for M.R. Young Unit 174 within a five (5) yearperiod and sixty two (62) start-ups for the same period for M.R. Young Unit 275

, it can be easily calculatedthatthis equates to an average ofapproximately twelve (12) start-ups peryear orroughly one (1) per month. However, in case ofUnit 1 only six (6) and in case of Unit 2 only seventeen (17) were considered "cold" start-ups, which are defined as the boiler having been withoutfuel-firing for more than seventy two (72) hours76•During shut-downs

1J. MinnkotaPowerCooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendorResponses on SCRTechnical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 & 2", May 8, 2008.
11 NOx Best Available Control Technology Analysis Study for Milton R. Young Station Unit 1 Minnkota PowerCooperative, Inc., Revised Final Report, October 2006, 311777.
1.2. NOx Best Available Control Technology Analysis Study for Milton R. Young Station Unit 2 Minnkota PowerCooperative, Inc. Operating Agentfor Square ButteElectric Cooperative, Owner. Revised Final Report, October 2006, 311777.

1§. MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA A-28ofless than seventy two (72) hours, SCR reactors are typically "buttoned up hot", which means the SCR reactor is isolated from the flue gas path during shut down by means of putting it in a bypass mode while the SCR is still at its design operating temperature. The cooling rate ofsuch a "buttoned up hot" SCR reactor is known to be extremely slow. Unless forced cooled with ambient airno "buttoned up hot" SCR reactor loses more than approximately 50

- 100 degrees and therefore gets nowhere nearthe sulfuric acid or even the moisture condensation temperature in a seventy two (72) hour period. Therefore, catalyst deactivation by means ofsoluble sodium compounds in the ash being dissociated into a liquid and penetrating into the catalyst pores and reacting there with the catalytically active 

### V20S must be expected to be rather slow. Since the actually experienced catalyst deactivation rate due to this effect has never been measured, the respective conclusion postulated by the Department cannot be considered more than an unsubstantiated speculation.


### 6.4 Differences in Flue Gas Composition
The Department concludes that "the flue gas generated atthe M.R. Young Station is different from the flue gas at any plantwhere SCRtechnology has been applied". The absoluteness of this statement, which is not even limited to powerplants, is quite amazing as it indubitably implies thatthe Departmenthas complete detailed knowledge not only ofthe flue gas composition ofevery other powerplant in the world equipped with an SCR system but also ofevery other plant in the world where the SCRtechnology is applied. Even though theoretically possible, the lack ofany data from all these otherplants strongly suggests that this may be highly questionable and largely overreaching. As a matter offact, 1am sure that I could easily present to the Department several plants where the SCRtechnology has been applied successfully thatthe Departmentdoesn't even know thatthese plants existed. Furthermore, the Department states thatthis absolute uniqueness is "primarily due to the high ash concentration ofsoluble sodium compounds and the total loading ofcatalyst deactivation chemicals". Again, as discussed in section 6.3 and clearly pointed out by catalyst suppliers, sodium is not a catalystpoison at SCRoperating temperatures77

. The claimed uniqueness of the flue gas generated atthe M.R. Young Station appears to be highly speculative and completely unproven as comparisons were only drawn to: bituminous coal (specifically mentioning Pennsylvania coal); sub-bituminous coal (specifically mentioning Wyoming PRB);

Comments Regarding SCR Technical Feasibility and Non-SCR Concerns Milton R. Young Station Unit 1 and Unit 2NOx BACT Analysis Study, April 18, 2007.
J1 MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendor Responses on SCR Technical Feasibility, North Dakota's NOx BACTDetermination forMilton R. Young Station Units 1 & 2", May 8, 2008. 

### A-29other lignites (specifically mentioning Texas lignite). Needless to say that Pennsylvania coal is notthe only bituminous coal in the world, Wyoming PRB iS,notthe world's only sub-bituminous coal and Texas lignite is referred to as Texas lignite for the simple reason that it is somewhat unique to Texas compared to the many othertypes oflignites and brown coals around the world. Thus, the Department's statement in its far reaching and absolute form must eitherbe considered extraordinarily uninformed or only correct ifrigorously limitedto the three specific coal types mentioned. In that sense this conclusion has little ifany relevance to the question ofthe technical feasibility ofthe SCR technology to the M.R. Young Station and should be simply ignored as completely irrelevant.


### 6.5 Experience ofBurns and McDonnell and Sargent and Lundy The Department concludes that "both Bums and McDonnell and Sargent and Lundy have extensive experience with the design and operation ofSCR systems". The fact ofthe matter is, however, thatthe SCRexperience ofBums & McDonnell must be considered rather limited for a number ofreasons, namely Bums & McDonnell has provided SCRrelated services for only seventeen (17) power'plants78. At least ten (10) ofthese are not even in operation yet and only two (2) SCRprojects are retrofits. Thus, Bums & McDonnell has very little experience with SCR retrofits and the only two (2) SCRretrofits, in which Bums and McDonnell was involved as Owner's Engineer, namely Hoosier Energy's Merom Station and HMPL's Henderson Station, have accumulated any appreciable long-term operating experience. However, in both ofthese cases, Bums & McDonnell's scope was limited to portions completely irrelevantto SCRprocess and catalyst design such as balance-of-plant design including foundations, electrical, controls integration, civil and contract oversighe9• In the case ofthe Henderson Station, the SCRwas supplied by Alstom and the catalyst by Cormetech. All process design, catalyst selection and design and all relevantprocess performance guarantees were provided by eitherAlstom or Cormetech. None were provided by Bums & McDonnell. In the case ofthe Merom Station, the SCRwas supplied by Lurgi and the catalystby KWH. Again, all process design, catalyst selection and design and all relevant process performance guarantees were provided by either Lurgi or KWH. None were provided by Bums & McDonnell. Detailed design is currently being provided by Bums & McDonnell for only one (1) power plant, namely Associated Electric's Thomas Hill Units 1,2 and 3. The SCRs are currently under construction and Bums & McDonnell lists conceptual design and studies" structural

1l! Summary ofResponses to EPAIDOH Questions onMinnkotaPower's NOx BACT Analysis for Milton R. Young Units 1 & 2, Presentation by EERC, MinnkotaPower, Bums & McDonnell to NDDH and U.S. EPA, May 23, 2007.
12. Ibid 

### A-30design, balance ofplant design and construction management as services provided8o• It is worth noting that again none ofthese services have anything to do with the SCRprocess or catalyst design. The only service provided by Bums & McDonnell for this one (1) SCR retrofit project at least remotely related to SCR process design was the selection ofthe reagent and the catalyst manufacturer. However, reagent selection is irrelevantfor catalyst deactivation and/or pluggage and the SCR catalyst itselfis supplied by CERAM including the design, sizing as well as all process performance guaranteesll

. Thus, the catalyst selection performed by Bums and McDonnell was nothing more than recommending CERAM as the catalyst supplier presumably on the basis ofa lowestprice competitive bidding process. In summary 

### it is worth noting that Bums & McDonnell has neither provided SCRprocess design and/or SCRprocess performance guarantees in one single case nor ever operated any SCR system. Thus, the Department's conclusion concerning Bums & McDonnell's "extensive experience with the design and operation ofSCR systems" seems to be based on a surprising lack offamiliarity ofthe true capabilities and limitations ofthese architect engineering (A/E) firms. Concerning the "extensive operating experience" the Department's conclusion is plain wrong and for the remainder coarsely exaggerating as no A/E ever provides any process and/or catalyst design and/orperformance guarantees. Even though Sargent and Lundy claims significantly more SCRexperience than Bums & McDonnell, Sargent and Lundy has also only acted as an A/E for SCRretrofits. Sargent and Lundy lists to have been involved in approximately 27,000 MWs ofSCRs as an A/E. This represents a little more than one fifth 

### e/s) ofthe SCRs retrofitted to coal-fired units in North America82 or less than halfofthe 46% claimed by Sargentand Lundy. Despite Sargentand Lundy's greater involvement in SCRretrofits as an A/E compared to Bums & McDonnell, it must be noted that Sargent and Lundy has also never provided any SCRprocess and/or catalyst design and/orperformance guarantees and never operated any SCR systems. Thus, the Department's conclusion concerning Sargent and Lundy's "extensive experience with the design and operation ofSCR systems" seems to be also based on a lackoffamiliarity ofthe true capabilities and limitations ofthese architect engineering (A/E) firms. Concerning the "extensive operating experience" the Department's conclusion is plain wrong and for the remainder at leasthighly questionable as no AlE ever provides and process and/or catalyst design and/orperformance guarantees. In general it must be noted that all services, which are critical for SCR system process design and process performance guarantees, including: process design;

Jill Summary ofResponses to EPAIDQH Questions on MinnkotaPower's NQx BACT Analysis for Milton R. Young Units 1 & 2, Presentation by EERC, MinnkotaPower, Burns & McDonnell to NDDH and U.S. EPA, May 23, 2007.
1U. Reference liston CERAM's website: www.frauenthal.net. Sargent and Lundy LLC, "Application ofSCR Technology to North Dakota Lignite Fuels", a PowerPoint Presentation, May 2007. A- 31catalyst sizing and design; flow modeling and SCR rector design; process performance guarantees; catalystperformance guarantees; have never been and most likely will never be provided by neither Bums and McDonnell nor Sargent and Lundy. All these critical services are always either supplied by an SCR equipment supplier (Alstom, Babcock Power, Babcock & Wilcox, etc.) orby the catalyst manufacturer (Argillon, CERAM, Cormetech, Haldor Topsoe, Hitachi, etc.). As a matter of fact, all catalyst related performance guarantees (NOx removal efficiency or activity, S02/S03 conversion rate, catalyst life or deactivation rate, etc.) are neverprovided by anyone otherthan the catalyst manufacturers. Even the SCR equipment suppliers only pass through the catalyst performance guarantees obtained from the catalyst manufacturerto the end customer. And at least two 

### (2) ofthese catalyst manufacturers, namely Haldor Topsoe and CERAM were clearly willing to provide industry standardtype performance guarantees for their**catalys~.** Notably, both ofthese catalyst manufacturers have extensive HDSCR experience with high sodium and potassium containing fuels such as biomass and/or lignite. It remains unclear why the Departmentdidn't exploit the statements ofthese highly experienced catalystmanufacturers further but rather relied on the AlE's who have no SCR process and/orcatalyst design experience, have neverprovided any SCRprocess and/or catalystrelated performance guarantees and have absolutely no SCR operating experience.


### 6.6 Development Stage ofHigh-Dust SCR
The Department states that "to design and install an SCR system for a cyclone-fired unit firing North Dakota lignite without obtaining additional data from bench scale would be experimentation". This conclusion is again in cleardisagreement with the statement of catalyst manufacturers such as Haldor Topsoe and CERAM, who were willing to provide industry standard type**cataly~t** performance guarantees even for HDSCR. This clearly indicates that both ofthese highly experienced catalyst manufacturers see no need for obtaining additional data from bench scale experimentation but feel to be in the position to design and install a HDSCR system atM.R. Young's Units 1 and 2. Needless to say that no catalystmanufacturer and/or SCR system supplier will tum down the opportunity for additional bench scale and/orpilottesting ifoffered as it always effectively presents itselfas a welcome possibility for risk free research paid by others. Also needless to say, every A/E, who typically charges billable manhours, will favor bench scale and/or pilot
MinnkotaPowerCooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendorResponses on SCRTechnical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 & 2", May 8, 2008. 

### A- 32testing, thus extending the life ofthe project andtherefore the amount ofmanhours billable. Furthermore, even ifHDSCR would not be economically viable, LDSCR orTESCR certainly would be and are indubitably technically feasible and applicable as clearly indicated by the multitude ofapplications ofthis principle ofthe SCRtechnology to a wide range ofprocesses (see also section 5 ofthis report). Why the Department essentially ignores all the statements by these catalyst manufacturers and insists stubbornly thattheir provided SCRcatalyst design84 is experimentation, remains a mystery.


### 6.7 Temperature Variations
The Departmentcorrectly states that "the temperature variation ofthe flue gas entering the (HD)SCR will adversely affectthe performance and must be resolved for successful application ofthis technology". However, the large temperature variations present atthese units is very unusual for coal-fired units including cyclone-fired units. 

### It is a unit specific problem related to the very unique design ofthe backpass ofthe boiler and the airpreheater ratherthan to cyclone-fired boilers and/orNorth Dakota lignite. According to the boiler supplier Babcock & Wilcox only four (4) ofthese type boilers including the two (2) at M.R. Young Station were ever**buil~,** which clearly makes this the exception ratherthan the rule. 

### In fact, such large temperature variations would notbe tolerable for any HDSCR installed after any type offiring system (single oropposed wall-fired, tangentially-fired, turbo-fired, cyclone-fired, etc.) burning any type offuel (bituminous, sub-bituminous, lignite, brown, etc. coal, oil, gas, biomass, etc.). Thus, the temperature variation problem, which Babcock & Wilcox indicated can be technically resolved by incorporating the appropriate and necessary measures for the modification ofthe boiler's backpass and possibly the lignite pre-drying**system~,** is no reason to determine thatthe SCRtechnology is technically infeasible for cyclone-fired units burning North Dakota lignite. 

### In a worst case scenario itmay make HDSCRthe economically less attractive alternative compared to LDSCR orTESCR due to the very unique boiler design employed atthe M.R. Young Station.


### 6.8 Catalyst Erosion
The Departmentconcludes that "there are unresolved issues regarding catalyst erosion from the ash generated atthe M.R. Young Station". This conclusion is not substantiated by any data and at leasthighly disputable based on long-term SCR operating experience in Europe. Units equipped with HDSCR systems firing up to 40% ash waste coals have been in

M MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendor Responses on SCR Technical Feasibility, North Dakota's NOx BACTDetermination for Milton R. Young Station Units I & 2", May 8, 2008. E-mail from Steve Moormann (Babcock &Wilcox) to RobertBlakley (Bums & McDonnell) dated 07/18/07. Ibid 

### A-33successful operation for almosttwo (2) decades now without any major operating problems or excessive catalyst erosion87•The average ash content ofCenterMine North Dakota lignite, which has an average heating value ofapproximately 50% ofbituminous coal, is less than about 8%wt88• Hence, approximately twice as much lignite must be burned for the same heat input compared to average bituminous coal. This, however, results still only in an equivalent average ash content ofabout 16%wt. ofcomparable bituminous coal, which is a factor of approximately 2.5 lowerthan the maximum ash contentthat HDSCRs have been exposedto successfully in Europe. As a matter offact, bituminous coals with ash contents in the range of 12

- 15 %wt. are considered normal in Europe and pose no erosion threatto SCR catalyst whatsoever. Consequently, preventing excessive ash erosion ofthe catalyst is simply a matter ofcorrect SCRdesign as has been proven extensively in Europe. Neither Bums & McDonnell nor Sargent and Lundy have any experience with HDSCR designs for higher ash coals or any experience with the operation ofHDSCRs on high ash units. This leads to the conclusion thatthe Department's concerns over seemingly unresolved issues regarding catalyst erosion appearto be the result ofa simple lack ofknowledge ofthe many HDSCRs that have been subjected to much harsher conditions for almosttwo (2) decades now. 

### 6.9 CatalystPoisoning, Blinding and Plugging The Department correctly states that "poisoning, blinding and plugging ofa catalyst are affected by the geometries and properties ofthe catalyst". However, subsequently, the Department concludes that "cyclone firing ofFort Union lignite and CenterMine coal results in a flue gas stream that highly accelerates poisoning, blinding and plugging (ofpores) due to the rich sodium and potassium vapors, particles and ammonia sulfates (due to ammonia injection) in lignite-fired cyclone flue gas". The categorical absoluteness ofthis statement is impressive as it rest solely on the highly questionable results ofthe ill-designed Coyote Pilot**Testin~.** As already elaborated on in detail in sections 6.2 and 6.3 ofthis report and confirmed by the Department90

, the data ofthe referenced Coyote PilotTesting is more or less useless. Despite the facts that: No deactivation data ofthe catalystwas everdetermined during or afterthe Coyote

.!IT Sobolewski, H, H. Hartenstein, H. Rhein, "STEAG's Long Term SCR Catalyst Experience and Cost", The 2005 EPRI Workshop on Selective Catalytic Reduction, Louisville, KY, November 2005

. .§J! MinnkotaPowerCooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA Comments Regarding SCR Technical Feasibility and Non-SCR Concerns Milton R. Young Station Unit 1 and Unit 2 NOx BACT Analysis Study, April 18, 2007. Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalyst performance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005.

90 Page 7 ofthe Preliminary BestAvailable Control Technology Determination forNitrogen Oxides for M.R. Young Station Units 1 and 2, Division ofAir Quality ND DepartmentofHealth, 918 E. Divide Avenue, Bismarck, ND, June 2008. 

### A-34Pilot Testing. The combination ofthe fatally flawed Coyote Pilot Testing reactor design, the inadequacy ofthe selected catalysttype and the extremely poor execution ofthe test runs caused the severe catalystpluggage after only two (2) months ratherthan the flue gas composition and/or ash characteristics as pointed by highly experienced catalyst manufacturers including CERAM and HaldorTopsoe2.l, who provided the catalyst for the Baldwin and Coyote Pilot Testing. The catalyst manufacturers most experienced with similar fuels (i.e. biomass, PRB, brown coal, etc.) clearly stated92 that:

o "the deactivation rate ofthe catalystwill be high but manageable" (Haldor Topsoe);

o "the information and test workpresented indicate that it is certainly premature to assume thatthere is a fatal flaw for the use ofhigh dust SCRbehind cyclones firing North Dakota lignite" (CERAM);

o they "are willing to warrantthe catalyst performance" based on industry standard terms (Haldor Topsoe);

o "a commercial offering regarding this project" can be provided (CERAM); the Department boldly decided that "the engineering solutions ofa larger SCR reactor, more catalyst and larger pitch do notresolve the rapid plugging ofcatalyst pores". This conclusion is in sharp contrastto the statements provided not only by the catalystmanufacturers most experienced with similartypes offuels but also with the statements made by some ofthe most experienced SCR system suppliers (Alstom, BabcockPower), who "expectthat an SCR system could be successfully utilized on a boiler fired with Northern lignite fueI93". The Departmentcontinues stating that "there is no catalyst vendor solution to reduce or eliminate pore plugging. The chemical and physical process ofpore plugging cannot be reversed, which dictates catalyst change out." This statement is simply incorrect as several well proven methods exist for successfully reducing and/or eliminating pore plugging and completely reversing sodium and potassium poisoning ofthe catalyst. For instance, Alstom in their correspondence with Bums & McDonnell points out several times94 that as a result of

.2.l MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA Comments Regarding SCRTechnical Feasibility and Non-SCR Concerns Milton R. Young Station Unit 1 and Unit 2NOx BACT Analysis Study, April 18, 2007.
2l Ibid
21 Ibid
2± Ibid A- 35the highly efficient flue gas cleaning equipment upstream ofa LDSCR orTESCR, the installation ofa LDSCR orTESCR would eliminate these issues. Furthermore, Haldor Topsoe points outthat "the expected poisons are mostly water soluble, therefore periodic waterwashing ofthe catalyst can be used to regain activity and to increase overall service life95". This is a clearreference towards the various in-situ96

, on-site97 and off-site98 catalyst washing, rejuvenation and regeneration processes that are commercially available and have been successfully used in the U.S. as well as in Europe for more than a decade now. These methods have proven beyond any doubtthe possibility ofregaining the catalyst's full initial activity for a fraction ofthe costofnew catalyst. They can also be applied multiple times to the same catalyst, particularly in case ofsodium and potassium poisoning as well as fly ash pluggage, where simple washing either in-situ99 or on sitelOO has yielded excellentresults. These various washing, rejuvenation and regeneration technologies have been utilized successfully by the U.S. utility industry since early 2003l.Ql. Why the Department ignores these facts and makes a statement in clear contradiction to all this evidence remains unknown.


### 6.10 Lack 

### ofPilot Scale Testing Data The Department states that "withoutpilottesting, the long termNOx reduction efficiency, the volume ofthe reactor, the catalystpitch, life ofthe catalyst, or even type ofthe catalystto be used cannot be predicted with a high degree ofconfidence." This statement is most interesting as is seems to be in clear contradiction to the Department's previous statements that: "Cyclone firing ofFort Union lignite and Center Mine coal results in aflue gas stream that highly accelerates poisoning, blinding and plugging (ofpores) due to the rich sodium and potassium vapors, particles and ammonia sulfates (due to ammonia

22. MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA Comments Regarding SCRTechnical Feasibility andNon-SCR Concerns Milton R. Young Station Unit 1 and Unit 2 NOx BACT Analysis Study, April 18, 2007.
2§ Maier, H, W. Gotz, "In Situ Catalyst Regeneration

- a Cost Saving**Tec~nology** for SCR Operators", a paper presented atPower Gen, 2001.
21 Nagai, Y, Y. Inatsune, I. Morita, Y. Kato, K. Yokoyama, K. Ito, P. Otte, "Rejuvenation ofthe SCR Catalyst atMehrum", a paperpresented atthe Electric PowerConference, 2004

. .2J! Hartenstein, H., H. Gutberlet, "CatalystRegeneration

- An Integral PartofProper Catalyst Management", The 2001 EPRI Workshop on Selective Catalytic Reduction, 2001.
22 Maier, H, J. Matschke, "RecentExperience With SCR Catalyst Regeneration", a paperpresented atthe DOE-NETL Conference on SCR/SNCR, 2001.

100 www.envirgy.com/en/references/catalyst regeneration.
lQl www.ebinger-kat.com/en/referenzen.php. 

### A-36injection) in lignite-fired cyclone flue gas". "The engineering solutions ofa larger SCR reactor, more catalyst and largerpitch do not resolve the rapid plugging ofcatalystpores." "The pilot scale (HD)SCRthat was deployed atthe Coyote Station was plugged and the catalystpores deactivated after 2 months (approx. 1,430 hours)" The Department believes successful operation is considerably more than a few thousand hours of operation." How can the Departmentpostulate on one hand that without further pilottesting long term NOx reduction efficiency or in other words catalyst deactivation and therefore catalyst life cannotbe predicted with a high degree ofconfidence, while claiming on the otherhand with the seemingly highest degree ofconfidence that: The flue gas composition leads to highly accelerated catalyst poisoning, blinding and plugging? Successful operation is considerably more than a few thousand hours based on the fact that the ill-design HDSCRpilot testreactorplugged after only two (2) months? Likewise how can the Departmentpostulate on one hand that such fundamental HDSCR design parameters as volume ofthe SCR reactor, catalystpitch and type ofcatalyst cannotbe predicted with a high degree ofconfidence, while claiming on the other hand with the seemingly highest degree ofconfidence that no engineering solutions ofa larger SCR reactor, more catalyst volume and larger pitch existto resolve the rapid plugging ofcatalyst pores? Unfortunately, the Departmentfails to resolve these obviously diametrically contradicting statements. Yet, it mustbe noted thatthe Department's claims concerning the rapid catalystpoisoning, blinding and plugging as well as the claim that no engineering solutions existto mitigate these, are solely based on the highly questionable results ofthe ill-designed Coyote Pilot Testing. Atthe same time, however, the Department states that without additional pilot testing none ofthese necessary predictions could be made since the Coyote PilotTesting was ill-designed and didn'tprovide much useful datalO2•This contradiction further nurtures the impression that the Department either solely relies upon orcompletely negates the Coyote PilotTesting results depending on what ever seems to favor the particular argument against SCR atthe moment
.

.!RPreliminary BestAvailable Control Technology Determination for Nitrogen Oxides for M.R. Young Station Units 1 and 2, page 7, Division ofAir Quality NO DepartmentofHealth, 918 E. Divide Avenue, Bismarck, NO, June 2008. 

### A-37

### 6.11 Lack ofVendor Guarantees
The Department states that "vendors cannotwithout further pilottesting, guarantee SCR system performance for M.R. Young Station boilers firing North Dakota lignite". This statement is simply incorrect as both CERAM and HaldorTopsoe clearly stated that they would be willing to offer industry standard type performance guarantees 103 for their catalyst for a HDSCR system installed atM.R. Young Station

- see also the discussion in section 6.9 ofthis report. The Department's claim that "even the most optimistic vendors don't offertrue guarantees of catalystperformance", is as incorrect as the first statement. Both, HaldorTopsoe and CERAM clearly stated that they would be willing to offer industry standard type guarantees for the performance oftheir catalyst for a HDSCR atM.R. Young Station. The fact that the Department argues that "the guarantee is limited to the contractvalue" merely unveils the Department's surprising lack offamiliarity with the type and extent ofperformance guarantees provided within the utility industry. The fact ofthe matter is that no equipment vendor in the utility industry ever accepts any liability for performance guarantees above and beyond the full amount ofthe contract value, which is exactly what was offered Le. by Haldor Topsoe104• This is not only common practice in the utility industry but also a well known fact to all A/E's including Bums & McDonnell and Sargent and Lundy. Ifasked, none ofthe eight (8) participants in the SCRVendor Query would offer an unlimited liability or even a limit ofliability ofmore than the contract value for performance guarantees. Bums & McDonnell as well as Sargent and Lundy, who themselves neverprovide any type of process or system performance guarantees what so ever, are fully aware ofthis fact and will surely admitto it ifasked. It is worth mentioning that in case a project such as an SCR retrofit atM.R. Young Station would be carried outby an AlE such as Bums & McDonnell or Sargent and Lundy as an owner's engineerfor Minnkota and/or Square Butte, the only performance guarantees the owner (in this case Minnkota and/or Square Butte) would ever receive would be the various system performance independentguarantees for the performance ofthe individual equipment and components supplied by the individual vendors including the one from the catalyst supplier. Each ofthese individual equipment and componentperformance guarantees would be limited to the value ofand the equipment and/or component supplied by the respective vendor and simply passed through by the AlE to the owner. Thus, none ofthese individual performance guarantees would come even remotely close to covering the entire value ofthe SCRretrofit as each one would represent only a small portion ofthe entire project. The owner (in this case Minnkota and/or Square Butte) would have no performance guarantee for

103 Minnkota PowerCooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA Comments Regarding SCRTechnical Feasibility andNon-SCR Concerns Milton R. Young Station Unit 1 and Unit 2 NOx BACT Analysis Study, April 18, 2007.

104 Minnkota Power Cooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendorResponses on SCR Technical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 & 2", May 8, 2008. A- 38the entire SCR system and not even any kind ofsystem performance guarantee from the 

### AlE that all the individually purchased pieces ofequipment

### andlorcomponents fit together as intended so thatthe entire system performs as intended. As a matter offact, the type and extent ofperformance guarantees offered by the catalyst suppliers CERAM and Haldor Topsoe including the stated limitation ofliability are most certainly exactly the same as were provided for each and every SCRproject, in which Bums & McDonnell and Sargent and Lundy were ever involved. Ifan owner seeks a true system performance guarantee that covers the entire scope ofthe project, no 

### AlE is needed. As a matter offact, an

### AlEis a hindrance in such a case as such true complete system performance guarantees are only offered by complete system suppliers such as Alstom, Babcock Poweror Babcock & Wilcox. Contrary to an

### AlE, these true system suppliers are willing and able to provide the entire scope ofa tum-key SCR retrofit including complete system performance guarantees for up to the value ofthe entire retrofit project, which is then again the value ofthe contract. Such a tum-key supply, however, eliminates the need for an ownerto additionally pay an

### AlE, which is the simple reason why these types ofcontracts are not favored by the AlEs. Yet, the most successful SCRretrofits in the U.s. were done as tum-key installations withoutthe use ofan

### AlE.


### 6.12 Review Authority
The Department claims the review authority for this case. I do not comment on this.


### 6.13 Conclusions
In conclusion, it mustbe stated thatthe Department made numerous factually incorrect claims, conclusions and statements as outlined in detail above. The most significant ones include: The conclusion that HDSCR is nottechnically feasible based on the data obtained from the ill-designed HDSCR Coyote Pilot Testing thatprovided little useful data

- see sections 6.2, 6.3 and 6.9. The conclusion that HDSCR is nottechnically feasible based on the lack ofany meaningful pilot testing data because the HDSCR Coyote Pilot Testing was illdesigned and provided little useful date

- see sections 6.4, 6.6, 6.8 6.10 and 6.11. The statementthat Bums & McDonnell and Sargentand Lundy have extensive experience with the design and operation ofSCR systems

- see section 6.5. The claim that vendors cannot guarantee SCR system performance for M.R. Young Station

- see section 6.11. 

### A-39The claim that LDSCR and TESCR are nottechnically feasible based on the data obtained from the ill-designed HDSCR Coyote PilotTesting that provided little useful data and must be considered completely irrelevant altogetherfor an LDSCR and/or TESCR design and application. It is worth pointing outthatthe Departmentcontradicted its own statements numerous times, particularly concerning the quality ofthe data ofthe HDSCR Coyote PilotTesting and the unavailability ofany really useful data from saidpilottesting. No explanation was offered why the HDSCR Coyote Pilot Testing data is condemned as inadequate in some cases, yet hailed as offering the absolute truth in some othercases. Depending on what seems to best fit the argument atthe moment that HDSCR is not technically feasible for the M.R. Young Station, the Department seems to either solely rely on this essentially useless Coyote Pilot Testing data, which appears to be the case for the Department's conclusions concerning catalyst: poisoning, blinding and plugging; deactivation and lifetime;

or seems to complain that no reliable pilottesting data is available, which appears to be the

.case for the Department's conclusions concerning catalyst: erosion; sizing (type, pitch, volume); performance guarantees from the vendors. The incorrectness ofthe Department's conclusions concerning the expected catalyst deactivation as well as the performance guarantees was pointed out by some ofthose, who know best, namely the catalyst manufacturers and SCR system supplierslOS. The Department's arguments concerning fuel variability and ash composition are true for all coals and by no means unique to this application and thus ofno relevance to this case. Likewise, the argumentconcerning unacceptable temperature variations and possible popcorn ash problems are also ofno further relevance to this case as all these issues would have to and can be successfully resolved regardless ofthe type ofcombustion system (i.e. cyclone fired) and/orthe type offuel burned (i.e. North Dakota lignite). Finally, the Department's conclusions againstthe technical feasibility ofLDSCR and TESCR are completely unsubstantiated and erroneous. Not only does the Department fail to

105 MinnkotaPowerCooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendorResponses on SCRTechnical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 & 2", May 8,2008. A-40correctly distinguish and separate these two (2) distinctly differenttypes ofSCR systems, it also concludes that "the (catalyst) deactivation issue for low-dust and tail-gas SCR remains as with the high-dust SCR". Deciphered in detail, this is the Department's only single argument againstthe application ofa LDSCR or TESCR, since all other argued issues are admitted to be "not unresolvable". Unfortunately, the Department again bases its erroneous conclusion concerning LDSCR and TESCR solely on the data obtained during the illdesigned HDSCR Coyote PilotTesting. As little ifany relevance this essentially useless data may have for an HDSCR application it most certainly has absolutely no relevance for a possible LDSCR and/or TESCR application. The Department fails to recognize this. A noticeably poor and incomplete attempt was made to provide at least some, however, not meaningful data for the flue gas and fly ash composition downstream ofthe ESP. This clearly suggests the lack ofany meaningful data for the correct evaluation ofan LDSCR. The only data provided was some sampling performed downstream ofthe ESP at a temperature of 300 F (149 cC), which is well below the temperature range of650

- 750 F (343

- 400 cC) required for LDSCR operation. Therefore, the deposition data cited by the Department from Minnkota's November 9,2007 response to comments 106 is not relevant for the flue gas conditions present in a LDSCR and even less for the flue gas conditions in a TESCR. Unquestionably, the condensation ofvapors including pyrosulfates and gaseous compounds responsible for the stickiness ofthe ash is a function oftemperature as condensation of vapors and gaseous compounds occurs progressively at lowertemperatures. The Department fails to explain how data concerning the stickiness ofthe ash particles collected on a silicon dioxide surface at 300 F (149 cC) would have any significant relevance for the prediction of catalyst pore pluggage by ashparticles at 650

- 750 F (343

- 400 cC). Absolutely no useful data characterizing the conditions downstream ofthe wet FGD was provided, thus making any conclusion concerning a TESCR nothing but presumptive speculation. The only at least somewhat factual attempts to argue why catalystdeactivation downstream ofa wet scrubber could be an issue is the Department's comment concerning the Minn-Dak Farmer's Coop's coal fired boilers and some convoluted data107

, which presumably obtained by means ofstacktesting downstream ofthe wet scrubber at M.R. Young Station's Unit 2. Using the Minn-Dak boilers 7A and 7B as an example, the Department argues that "MinnDak had trouble complying with its particulate matter emission limit due to sodium compounds passing through the airpollution control device. In orderto maintain compliance, the ash Na20 content ofthe coal combusted had to be limited". The Department argues that this is sufficient support for the Department's conclusion that "alkali mineral compounds are not removed by the ESP or S02 scrubbing system". As a result the Department argues that "it

106 Response letterto EPA's October4, 2007 letter sent from Minnkota Power Cooperative, Inc. to Mr. Terry O'Clair, Director, Division ofAir Quality atthe North DakotaDepartmentofHealth, dated November 9, 2007.

107 Minnkota Power Cooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA Comments Regarding SCR Technical Feasibility and Non-SCR Concerns Milton R. Young Station Unit 1 and Unit 2 NOx BACT Analysis Study, April 18, 2007. A- 41appears a significant amount ofsodium compounds, a catalystpoison, will enter a low-dust ortail-gas SCR system. The deactivation issue for low-dust and tail-gas SCRwill remain the same as for the high-dust SCR. The research, design and pilottesting needed to develop an SCR system that will have reasonable success makes this technology also not applicable at this time." As will be shown in detail in section 7 ofthis report, no research, design and/orpilot testing is needed to install a TESCRthat will have complete success at M.R. Young Station. The Minn-Dak experience cited by the Department, however, is by no means ofany relevance to the technical feasibility ofa TESCR at M.R. Young Station, yet it seems to form the sole and only basis for the Department's reasoning that TESCR is not applicable atthis time. Reviewing Minn-Dak's Air Pollution Control Title V Permitto Operate108 and the North Dakota Department ofHealth's Inspection**Repo~,** it becomes evidentthat neitherthe particulate matter removal device northe wet scrubber are comparable to the airpollution control equipment installed orunder construction atM.R. Young Station. Minn-Dak's boilers 7A and 7B, which are two Babcock & Wilcox stoker-fired boilers burning coal, biogas and natural gas, are equipped with multi-cyclones and co-currentventuri scrubbers ratherthan ESPs and counter-current spray towers. The coal burned was reported to be sub-bituminous coal from the Spring Creek Coal Company in Montana ratherthan North Dakota lignitellQ

. Not only is the partitioning ofthe ash constituents ofthe coal that occurs in a cyclone-fired boilerdifferent from that in a stoker-fired boilerillbut also is said partitioning different for different coals. Thus, using data from a stoker-fired unit burning PRB to predictthe partitioning at a cyclone-fired unit burning North Dakota lignite is simply inappropriate. As correctly stated by the Department, Minn-Dakhas a restriction on the sodium content in the coal at 2.8% NazO on a dry mass basis in the coal ash in orderto meetthe particulate emission limit of45.5 lb/hr, which, however, equates to 0.40 Ib/l06 Btu ratherthan 0.10 Ib/l06 Btu as erroneously claimed bythe Department. It is critically importantto note thatthe sub-bituminous coal fired at Minn-Dakill. has an ash content ofapproximately 4

- 5%, which is typical for sub-bituminous coal and not about 8

- 10% on average as North Dakota lignite. In otherwords, North Dakota lignite has abouttwice the amount ofash compared to subbituminous coal. Furthermore, it is importantto realize thatthe sub-bituminous coal burned atMinn-Dak has only between 0.3% and 0.5% sulfur, which means thatthe uncontrolled SOz

108 State ofNorth Dakota, Department ofHealth, Division ofAir Quality, AirPollution Control Title V Permit to Operate, PermitNumberT5-X78001 issued on 7/31/2006.

109 North DakotaDepartment ofHealth, Inspection Report, issued on 10/27/2003.
llQ Ibid
ill Response letterto EPA's October4, 2007 letter sent from MinnkotaPower Cooperative, Inc. to Mr. Terry O'Clair, Director, Division ofAir Quality atthe North DakotaDepartmentofHealth, dated November 9, 2007.
ill State ofNorth Dakota, DepartmentofHealth, Division ofAir Quality, AirPollution Control Title V Permit to Operate, PermitNumberT5-X78001 issued on 7/31/2006. A-42emissions range between 0.7Ib/l06 Btu and 1.1 Ib/l06 Btuill
, which compares very favorably to a permitted emission limit of3.0 Ib/106 Btu. The measured S02 emission rate was reported to be around 0.1 lb/l06 Btu at atime when the uncontrolled emission rate was theoretically and not accounting for any S02 being captured in the fly ash only about 0.7 lb/l06 Btu (based on the coal data included in the report), which suggests a S02 removal rate ofno more than atthe most 70%ill:. Combining this with the fact thatthese stoker fired units have no ESP but are equipped with only multi-cyclones as primary particulate control devices, suggests very strongly thatthe co-current venturi scrubbers were never intended to remove any significant amounts ofS02 but where designed as additional particulate removal devices. Multi-cyclones are comparatively simple devices designed for the removal ofonly the coarsest fly ash particles. Therefore, multi-cyclones have not been used in utility boilers for more than 40 years anymore. Due to the fact that multi-cyclones are based on the principal of centrifugal forces removing the particles, only the largest and heaviestparticles can be removed. Contrary to that, ESPs electrically charge all sizes ofparticles, which are then removed in an electric field as a result oftheir electric charge. Therefore, ESPs are much more effective removal devices for particulate matter, particularly for very small particles. Since PRB is known to generate a comparatively larg<;: fraction ofvery fine ash particles and since these stoker-fired units were most likely not designed for burning PRB, it is quite conceivable why the units didn't meettheir particulate emission limit while burning PRB. Not being equipped with particulate control devices suitable for the removal offine particles, limiting the sodium content in the ash serves as means to limitthe amount ofvery small particles formed. Co-current venturi scrubbers are particulate removal devices, which operate on the principle ofinertial impaction ofsmallerparticles on waterdroplets as a result oflargely different velocities. Again, only the largerparticles have enough mass and therefore inertiato be removed successfully. Small particles with a small mass and therefore very little inertia follow the gas stream and successfully evade impaction. Contrary to that, counter-current spray towers designed for S02 removal are based on the principle ofoffering a large amount offinely dispersed liquid for the rapid cooling ofthe flue gas to its saturationtemperature followed by the absorption ofgaseous airpollutants such as S02. During the rapid cooling of the flue gas with a large excess ofwater, the very small particles, which provide a comparatively large surface area, act as condensation nuclei and are absorbed into the

. scrubbing solution. Also, the flue gas residence time in a counter-current spray tower is much longerthan in a co-current venturi scrubber, which further assists removing small particles. Suggesting thatthe flue gas inletcomposition to a TESCR downstream ofan ESP and a counter-current wetflue gas desulfurization scrubber is even similarto the flue gas composition downstream ofa multi-cyclone and a co-current venturi scrubberdesigned for

ill. North DakotaDepartment ofHealth, Inspection Report, issued on 10/27/2003.
ill Ibid A-43coarse particulate removal is truly creative. Yet, the fact ofthe matter remains thatthe MimlOak experience is not comparable to the situation atthe M.R. Young Station due to the different: coal burned (PRB versus North Dakota lignite); combustion system design (stoker fired versus cyclone fired); primary particulate matter removal device (multi-cyclone versus ESP);
wet scrubber design and purpose (co-current venturi for particulate removal versus counter-current spray tower for S02 removal). Thus, the Minn-Dak experience mustbe considered completely meaningless and irrelevant for the possible application ofa TESCR at the M.R. Young Station. In Minnkota's April 

### 18,2007 response to question from the Departmentill
, Minnkota states that "stack sampling was conducted downstream ofthe ESP and wet FGD on Unit 

### 2." However, itremains unclear whetherthe dataprovided represents samples taken downstream ofthe ESP or samples taken downstream ofthe wet scrubber. Furthermore, even ifthe data represents samples downstream ofthe wet scrubber, it is unknown whetherthe samples were taken downstream ofthe wet scrubberbut upstream ofthe bypassing flue gas re-entering the flue gas streamto the stack ordownstream ofthe bypass re-entry point. These questions are very relevant, since the flue gas stream downstream ofthe ESP and upstream ofthe wet scrubber is significantly different from the flue gas downstream ofthe wet scrubber. Likewise, the flue gas stream downstream ofthe wet scrubberbutupstream ofthe bypass reentry point is significantly differentthan the flue gas downstream ofthe bypassing flue gas re-entering the flue gas stream coming from the wet scrubberto the stack. An e-mail string between Minnkota and Bums & MacDonnelllli seems to indicate that at leastthe sampling may have been done downstream ofthe wet scrubber and downstream ofthe bypass re-entry point ofthe flue gas for reheating. Ifthis is confirmed than this data is completely useless for the correct characterization ofthe flue gas stream entering a TESCR as approximately 

### 18% ofthe flue gas bypassed the wet scrubber atthe time ofsamplingill. This means thatthe flue gas sampled clearly does not represent what would enter a TESCR as everything that is removed in a wet scrubberwas still present in almost one fifth ofthe flue gas during sampling. Since the sampling was clearly not intended to characterize the flue gas composition entering a TESCR but intendedto prove the particulate removal downstream of the ESP, this data cannot be considered relevant for any reasonablejudgmentconcerning the technical feasibility ofa TESCR.

ill MinnkotaPower Cooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA Comments Regarding SCR Technical Feasibility andNon-SCR Concerns Milton R. Young Station Unit I and Unit 2 NOx BACT Analysis Study, April 18, 2007.
ill E-mail string from John Graves (Minnkota) to Robert Blakely (Bums & McDonnell) dated April 12, 2007.
ill Ibid A-44Also, no flue gas characteristics (temperatures, velocity, composition, etc.) atthe sampling point are provided. Without exact knowledge ofall these important details, the provided data is useless even for any reasonablejudgmentconcerning a LDSCR. However, even ifsome of this missing information would be made available, the data would still be meaningless unless the total mass flow or at leastthe total concentration ofthe various compounds in the flue gas would be provided. The provided data only offers a morphological composition analysis of the samples expressed in relative percentages ofthe various elements as a portion ofthe entire sample. No information about the absolute amount ofthe various compounds as well as their aggregate state was made available, which renders the data in its provided form as absolutely useless for any meaningful interpretation concerning expected catalyst deactivation rates. Why only this by itselfcompletely useless portion ofthe data was provided while all information needed to make the data possibly meaningful was withheld (assuming thatthis information exists), remains unknown. While the Department devotes forty (40) pages ofthe seventy two (72) page documentto arguments why HDSCR should be considered technically not feasible, little more than two (2) pages are dedicated to LDSCR and TESCR combined. Ofthese two (2) pages little more than one (I) page deals with possible site constraints and flue gas reheating, both ofwhich are correctly dismissed as being economic considerations instead oftechnical feasibility issues, thus leaving about only one (1) page for the combined evaluation ofLDSCR and TESCR. This one (1) page states the Department's conclusion that a LDSCR and/or a TESCR are technically infeasible without presenting any relevant supporting data. The Department's conclusion rests solely on the incorrect, unsupported and unfounded claim that "the deactivation issue for low-dust and tail-gas SCR remains the same as for high-dust SCR". However, only a few paragraphs later, the Department contradicts this earlier statement by postulating that "catalyst deactivation ofa low-dustortail-gas SCRdue to alkali compounds is an issue that will require extensive research, design and pilottesting to determine whetherthe technology can be successfully applied to units fired on North Dakota lignite". Eitherthe Department can provide relevant supporting data for the claim thatthe deactivation issue in aTESCRremains the same as in a HDSCR, or such supporting data doesn't exist, in which case the claim is purely speculative and unsupported. It is also a fact thatthe SCR Vendor Query conducted by Bums & McDonnell very specifically stated that itwas solely directed towards HDSCR, thus ignoring LDSCR and TESCR. Why attempts by various vendors (Alstom, BabcockPower, CERAM) to also consider LDSCR and/or TESCR were seemingly ignored remains unexplained. Thus, the final conclusion reached by the Departmentthat HDSCR is nottechnically feasible is unacceptable. All the presented data, investigations, vendor information etc. most certainly don't allow the conclusion that HDSCR is nottechnically feasible. Concluding that HDSCR is technically infeasible is premature and unfounded. Furthermore, the Department's conclusion that LDSCR and TESCR are both nottechnically feasible is clearly presumptive and speculative as this conclusion cannotbe supported by any relevant data, investigation or vendor information. Additionally, itmustbe stated thatthis 

### A-45conclusion is wrong as the only one (1) claim ofexcessive catalystdeactivation made against TESCR is clearly technically not defendable. In summary, this leads to the conclusion thatthe Department's statementthat that SCR technology is nottechnically feasible for application atthe M.R. Young Station's cyclonefired units burning North Dakota lignite is incorrect. HDSCR may very well be technically feasible, LDSCR is most likely technically feasible and TESCR is most certainly technically feasible for application atthe M.R. Young Station's cyclone-fired units burning North Dakota lignite. With at least one SCR principle, namely TESCR being most certainly technically feasible for the application atthe M.R. Young Station, the Department's BACT analysis incorrectly eliminatedthe SCRtechnology from further consideration.



### 7. VENDOR QUERY TAIL-END SCR
In orderto further substantiate the technical feasibility ofTESCR for the M.R. Young Station, the same eight (8) vendors were contacted that also participated in the Vendor Query conducted by Bums & McDonnellill

. Due to vacation schedules and otherpersonal restrictions only six (6) ofthe eight (8) vendors contacted were able to provide written responses, while two (2) could provide only verbal responses. Also, time constraints demanded thatthe scope and extent ofthe discussion withthese eight (8) vendors had to be limited to some very fundamental questions concerning TESCR. Since catalyst deactivation seems to be the primary concern ofthe Department, more time was devoted to communication with the catalyst manufacturers (Argillon, CERAM, Cormetech, Haldor Tospoe, Hitachi) as they are ultimately the ones, who provide the process performance guarantees for the catalyst. Somewhat less time was devoted to the SCR equipmentvendors, who ultimately also rely on the catalyst manufacturers for catalyst performance and deactivation information and guarantees. Therefore, the response ofthe catalyst manufacturers was considered to be most meaningful, particularly the responses of the ones with extensive TESCRexperience. Again, more time was devoted to the companies with TESCR experience (Alstom, Argillon, CERAM, BabcockPower, Haldor Topsoe) comparedto the ones with no TESCR experience (Babcock & Wilcox, Cormetech, Hitachi). The following eight (8) vendors were contacted: SCRequipment vendors:

o Alstom

- Mr. Michael Philips was not available due to time constraints and therefore directed me to Mr. John Buschmann, SCRProduct Manager at Alstom, who provided only a verbal response due to insufficienttime for a

ill. Minnkota PowerCooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA Comments Regarding SCR Technical Feasibility andNon-SCR Concerns MiltonR. Young Station Unit 1 and Unit 2 NOx BACT Analysis Study, April 18,2007. 

### A-46written response. Alstom has extensive TESCRexperience.

o BabcockPower

- Dr. Clayton Erickson provided a written statement. BabcockPower has access to extensive TESCR experience and is the equipment supplier ofthe LOCSR downstream ofa cold-side ESP under construction as WE Energies' South Oak Creek Station.

o Babcock & Wilcox

- Mr. Steve Moormann could not be reached. Instead, Mr. Donald Tonn, SCRProcess Expert at Babcock & Wilcox in Barberton, OH was contacted and provided a written response. Babcock & Wilcox has no TESCR experience. SCR catalyst manufacturers:

o Argillon

- Mrs. Cindy Khalafprovided a written statement. Argillon has extensive TESCRexperience.

o CERAM

- Mr. John Cochran provided a written statement. CERAM has extensive TESCRexperience.

o Cormetech

- Mr. Scot Pritchard provided a written statement. Cormetech has no TESCR experience but some LOSCRexperience.

o HaldorTopsoe

- Mr. Flemming Hansen provided awritten statement. Haldor Topsoe has extensive TESCRexperience.

o Hitachi

- Mr. Anthony Favale provided only a verbal response due to insufficienttime for a written response. Hitachi has no TESCRexperience but some LOSCRexperience. Due to the time constraints, the person named above at each ofthe eight (8) vendors was contacted by phone and informed aboutthe purpose ofthe discussion as well as asked whether he or she would be willing to provide a briefstatement in writing pere-mail. All contacted people agreed to provide a written statement. However, Messrs. John Buschmann ofAlstom and Anthony Favale ofHitachi who could provide only provide a verbal response due to time constraints as the written response would have arrived afterthe submission of this report. All eight (8) vendors, namely three (3) SCR system suppliers (Alstom, BabcockPower and Babcock & Wilcox) and five (5) SCR catalyst suppliers (Argillon, CERAM, Cormetech, HaldorTopsoe and Hitachi) were asked to provide answers to the following three (3) questions: Given your knowledge aboutthe plant (cyclone-fired B&W boilers, ESP, wet scrubber) and the fuel (NO lignite), would 

### <company>: a. Consider atail-end SCRtechnically feasible? 

### A-47b. Recommend orrequire additional pilottesting? c. Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime? Ifso what would these be? All eight (8) vendors answered the question a. with a clear "yes". None ofthe vendors expressed even the slightest doubts thatTESCR would not be technically feasible for both units atthe M.R. Young Station. All three (3) contacted SCR system suppliers and all responding five (5) SCR catalyst suppliers consider TESCRto be unquestionably technically feasible for cyclone fired units burning North Dakota lignite. All five (5) responding catalyst manufacturers answered question b. with a clear "no", thus dismissing any need for any further pilottesting for a TESCR application at M.R. Young Station. Likewise, the SCR system suppliers BabcockPower and Alstom also dismissed any need for any additional pilottesting for a TESCR. The only SCR system supplier, who stated thatthey "would require further discussion with the catalyst suppliers", was Babcock & Wilcox. This caution is simply the result ofthe lack ofexperience ofBabcock & Wilcox with TESCRs. Given the fact that even though Babcock & Wilcox has a license from Hitachi for SCR catalyst but Hitachi has no experience with TESCR either, such caution is no surprise. All five (5) responding catalyst suppliers and all three (3) SCR system suppliers answered question c. with a clear statementthatthey would provide common commercial performance guarantees. Argillon indicated 90% NOx removal efficiency at less than 2 ppmvd @ 3% O2 NH3 slip and greater 24,000 SCR operating hours catalyst life. Obviously, more details would have to be determined as the project would need to be defined better. Only Babcock & Wilcox statedthatthe commercial guarantees would have to be discussed first with the catalyst suppliers before passing them on to the buyer. Hitachi stated thatthey would have to see the exact flue gas composition in orderto determine what commercial guarantees would be provided. Again, this can be explained by the fact that neither Babcock & Wilcox nor Hitachi has any TESCR experience and did nothave time to evaluate a TESCR application for M.R. Young Station in sufficient detail. Additionally, during the verbal discussions with all four (4) catalyst suppliers as well as all three (3) responding SCR systems suppliers, the contactpersons made itvery clearthattheir companies would not consider HDSCR as technically infeasible atthis time. Particularly, all five (5) responding catalyst suppliers very adamantly statedthat the existing knowledge does not supportprematurely discarding HDSCR as a technically feasible possibility. All five (5) responding catalyst suppliers suggestedthatproperly designed and executed HDSCRpilot testing would certainly be helpful to decide whetherHDSCR would be more economically attractive than LDSCR or TESCRfor the M.R. Young Station. The e-mail correspondence of all six (6) vendors, who responded in writing, is presented in detail in Appendix A.



### A-48

### 8. SUMMARY
In summary, it must be concluded that TESCR is not only technically feasible butmay be even the most economical SCR alternative for M.R. Young Station. As reiterated by the responding vendors, the very high removal efficiency ofthe ESP and wet FGD upstream ofa TESCR combined with the flue gas reheating from the flue gas dew pointprovides flue gas conditions, which are unquestionably much more favorable for SCR catalystthan the conditions present in almost all HDSCRs. Two decades ofTESCRexperience in Europe have proven that TESCR can be successfully applied to the most complex processes and the most difficultflue gases. Catalystreplacement in mostTESCRs has been minimal to none. Most coal-fired units equipped with TESCRs still utilize the initial catalyst fill after more than 130,000 SCR operating hours. Due to the greatly reduced mass flow ofcatalystpoisons to the SCR catalyst the catalystdeactivation rates in TESCRs have proven to be extremely low, in some cases barely measurable. Additionally, minimal unit downtime for TESCRtie-in resulting in very little ifany lost generation is a huge advantage for TESCRs as they can be constructed typically completely independentofand parallel to unit operation. Flue gas reheat cost is relatively low as the flue gas needs to be reheated with high pressure steam only by about 18

- 65 degrees (10K

- 35 K) and the condensate from the steam coil is typically further used for dilution air heating and subsequent feed water before returned to the condensate from the turbine.

2BO"C PO7. 34mb., 02

## B.~~; 

# I

S02 260mgim' 'j CO 8. 59mg1m ' j NO. 103mgim 3 A

, stBubO.01E i NOxi1230ntgINm'!5%02 

## I

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# f
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-**10~** 2 % l66'C 76.2bar**~X** 3 FGOPFVERS OENOX 02B

... EIN 009 FGVERDlFTGEBL SAENTWAsSERUNG FOMenge 213 kg/'

... EIN 002 EIN RG-Menge 371m's VWVERotFTGEBL BAN'E-ENTSP NOXSW 105m91NIII' VOOWAHLl ErN NH3 SW 301kg/. E f

### ~~.~E~Ng6 NH3 Konzontr.l4.1

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....**~-.;--=_·~-:1~4!!3-b;.rJiiiiliii~,.~** VWNH3EINO 45.3% 

### I 478"C REliELVENT 1 • I SW 290'C AUF 54.2·c I

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# -

---**~-~--** --- ----- r-**-·-----r~----** -- ---- r- ,- r**~-** -- 1----

, . I 

# :------.----11-- ---·1
- :: ; I 

# i

A-49The graph above presents a typical process flow diagram from a TESCR on a 300 MW coalfired unit. This TESCR has operated for more than 130,000 hours for more 20 years now on the initial fill ofcatalyst with a continuous NOx removal efficiency in excess of91 %. As can be seen on the graph, the high pressure steam used for reheating is cooled from about 892 F (478°C) to ultimately 410 F (210°C) after dilution air and feedwater heating and priorto being discharged to the feedwater storage tank. Also worth noting is the small amount of only 18 degrees F (10K) that need to be added to the flue gas by means ofhigh pressure steam. As can be seen, the flue gas downstream ofthe gas-gas heat exchanger enters the steam coil with a temperature ofapproximately 534 F (279°C) and enters the SCR reactor downstream ofthe steam coil with a temperature ofonly about 552 F (289°C). This proves the high efficiency ofthe gas-gas heatexchanger and the small amountofhigh pressure steam needed for flue gas reheating, which makes this concepteconomically more attractive. In the

# u.s. currently both 325 MW units at PSE&G's Mercer Generating Station are equipped with TESCRs with flue gas reheat downstream ofthe ESPs. Spray dryer absorbers followed by baghouses downstream are being added downstream ofthe SCRs, thus effectively converting them from TESCRs to LDSCRs.**Th~** same type SCRwith flue gas reheat is currently being installed at WE Energies South Otter Creek Generating Station. Thus, LDSCR and/orTESCR systems can neither be dismissed as being technically infeasible nor based on economic reasons. Particularly the TESCRprinciple was developed specifically in orderto successfully adaptthe SCRtechnology to units with the most difficult flue gas compositions and the most complex retrofit challenges. During its 22 years of extraordinarily successful operating history, the TESCRprinciple has not only unconditionally proven itselfas one ofthe most viable SCRprinciples but certainly the most universally applicable ofall SCRprinciples.

A- 50

### Appendix A: Data and Information Considered
"Alternative Control Technologies DocumentNOx Emissions from Utility Boilers" March 1994. U.S. EPA, Office ofAir and Radiation, Office ofAir Quality Planning and Standards. This information can be found at website address: http://www.epa.gov/ttn/catc/dir1/utboiler

.pdf. Amended SIP Permitto Operate, letter from the North Dakota Department ofHealth to John Graves, Minnkota Power Cooperative, dated February 5, 2002. Ando, Jumpei, "S02 and NOx Removal for Coal Fired Boilers in Japan," presented atthe Seventh Symposium on Flue Gas Desulfurization, May, 1992. Argillon's website: www.argillon.com.
Assessment ofS02and NOx Emission Control Technology in Europe, Air and Energy Engineering Research Laboratory, EPA-600/2-88-013, February 1988.
Attachment 10, "Initial Design" BoilerHeat Input Rating vs "As Built" Boiler Heat Input Rating, George W. Button, January. 2001.
Attachment 11, Expert Opinion Report, Maximum Boiler Heat Input Capacity Units 1 and 2 Milton R. Young Station, Minnkota Power Cooperative, Inc. Center, N.D., 58530, Robert L. Pearson, Ph.D., PE, CH2M Hill, 100 Inverness Terrace East, Englewood, CP 80224, ca. 2001. Benson, A. J. D. Laub, C. R. Crocker, J. H. Pavlish, "SCR catalystperformance in flue gas derived from subbituminous and lignite coals", Fuel Processing Technology 86 (2005) pages 577

- 613,2005. "Compilation ofAir Pollutant Emission Factors AP-42, Fifth Edition, Volume 1: Stationary Point and Area Sources, Chapter 1.1, Bituminous and Subbituminous Coal Combustion" dated July 1993. Current Status ofSCR in Japan. by: Yasuyuki Nakabayashi and Rikiya Abe, Research and Engineering office, Thermal PowerDepartment, Electric Power Development Co., Ltd. Tokyo, Japan 100. ca 1987. Cyclone NOx Control: Technology and Issues Assessment, Electric Power Research Institute, 1998.

A- 51East Texas Electric Generating Facilities (EGFs) StakeholderMeeting Summary, TCEQ East Texas rulemaking concept, Austin, Texas, November 18,2005.
E-Mail from Randy Sadleron behalfofCindy Khalaf, President ofArgillon LLC, supplier ofthe SCRcatalyst for Oak Grove 1 & 2, dated June 24, 2008. E-mail from Flemming Hansen (Haldor Topsoe) dated June 30, 2008. E-mail string from John Graves (Minnkota) to Robert Blakely (Bums & McDonnell) dated April 12,2007. E-mail from Steve Moormann (Babcock &Wilcox) to Robert Blakley (Bums & McDonnell) dated July 18,2007. EPA-450/3-92-004, Office ofAir and Radiation, Office ofAir Quality Planning and Standards, "Summary ofNOx Control Technologies and theirAvailability and Extent of Application", February 1992. Erickson, C., S. Straight, L. Hutcheson, "Coal-Fired SCR Operating Experience with High Removal Efficiency and Low-NOx Firing Systems", BabcockPower's website: www.babcockpower.com.
Exclusive analysis ofTXU court decision;an article published in PowerEngineering, September2006. Feasibility and Cost ofSCRNOx Control in Utility Applications, RP 1256-8 prepared by United Engineers and Constructors, Inc. for Electric Power Research Institute (EPRI), August 1989. Fisia Babcock GmbH (formerly L&C Steinmiiller GmbH) and BabcockPower, Inc. reference lists SCR systems. Hartenstein, 

### H., H. Gutberlet, "CatalystRegeneration

- An Integral Part ofProper Catalyst Management", The 2001 EPRI Workshop on Selective Catalytic Reduction, 2001. Hartenstein, H., H. Gutberlet, L. Licata, "Utility Experience with SCR in Germany", a paperpresented atthe Sixteenth Annual International Pittsburgh Coal Conference, October 1999. Institute ofClean Air Companies (ICAC) letterto Michael Leavitt, USEPA Administrator dated July 15,2004.

A-52Impact ofTexas Lignite Coal on SCRCatalystLife and Performance, Field Datafrom TXU's Martin Lake Plant, EPRl Report 1004732, Electric Power Research Institute, December2003. Jones, 

### R, Introductory presentation atthe GulfCoast Power Spring Conference, April 2006. Maier, H, J. Matschke, "RecentExperience With SCR Catalyst Regeneration", apaper presented atthe DOE-NETL Conference on SCR/SNCR, 2001. Maier, H, W. Gotz, "In Situ Catalyst Regeneration - a Cost Saving Technology for SCR Operators", a paperpresented at Power Gen, 2001. Martin, M., M. Harrell, J, Jancauskas, H. Hartenstein, H. Sobolewski, "Large Particle Ash (LPA) Screen Retrofits at Coal-Fired Units in Indiana and Ohio", DOE-NETL Conference on SCR/SNCR, 2006. McIlvaine Utility E-Alert#868, April 4, 2008.
McIlvaine Utility E-Alert#871 dated April 25, 2008. McIlvaine Utility E-Alert#870 dated April 18, 2008. McIlvaine Utility E-Alert#874 dated May 16,2008. Milton R. Young Station

- OurJewel on the Prairie, brochure published by Minnkota Power Cooperative and Square Butte Electric Cooperative on Minnkota's website: www.minkota.com. Minnkota Power Cooperative, Inc. and Square Butte Electric Cooperative, "Additional Information and Discussion ofVendor Responses on SCR Technical Feasibility, North Dakota's NOx BACT Determination for Milton R. Young Station Units 1 & 2", May 8, 2008. Minnkota Power Cooperative, Inc. and Square Butte Electric Cooperative, Responses to NDDH and EPA Comments Regarding SCRTechnical Feasibility and Non-SCR Concerns Milton R. Young Station Unit 1 and Unit 2 NOx BACT Analysis Study, April 18,2007. Nagai, Y., Y. Inatsune, 

### 1. Morita, Y. Kato, K. Yokoyama, K. Ito, P. Otte, "Rejuvenation of the SCR Catalyst atMehrum", a paperpresented atthe Electric PowerConference, 2004. North Dakota Department ofHealth, Inspection Report, issued on 10/27/2003.
A- 53NOx Abatement for Stationary Sources in Japan, Jumpei Ando, EPA/600/7-81-030, May 1983. NOx Abatement for Stationary Sources in Japan, Jumpei Ando, Heiichiro Tohata, Katsuya Nagata, and B.A. Laseke. EPA/600/7-77-l03b, September 1977. NOx Best Available Control Technology Analysis Study for Milton R. Young Station Unit 1 Minnkota Power Cooperative, Inc., Revised Final Report, October 2006, 311777.
NOx BestAvailable Control Technology Analysis Study for Milton R. Young Station Unit 2 Minnkota Power Cooperative, Inc. Operating Agent for Square Butte Electric Cooperative, Owner. Revised Final Report, October 2006,311777. NOx Control Field Test Results on Coal-Fired Cyclone Boilers-CNCIG Programs, Electric Power Research Institute, 1999. Preliminary Best Available Control Technology Determination for Control ofNitrogen Oxides for M.R. Young Station Units 1 and 2, Division ofAir Quality, North Dakota Department ofHealth, 918 East Divide Avenue, Bismarck, North Dakota. Preliminary Best Available Control Technology Determination forNitrogen Oxides for M.R. Young Station Units 1 and 2, Division ofAir Quality ND DepartmentofHealth, 918 E. Divide Avenue, Bismarck, ND, June 2008. PSD Applicability Determination M.R. Young Station Unit 1 Turbine Upgrade, letterfrom the North Dakota Department ofHealth to John Graves, Minnkota Power Cooperative, dated March 11,2005. Reference list on CERAM's website: www.frauenthal.net.
Reference list on Ebinger Katalysatorservice's website: www.ebingerkat.com/en/referenzen.php Reference list on Envirgy's website: www.envirgy.com/en/references/catalyst regeneration. Response letterto EPA's October4, 2007 letter sentfrom Minnkota PowerCooperative, Inc. to Mr. Terry O'Clair, Director, Division ofAir Quality at the North Dakota Department ofHealth, datedNovember 9,2007. Sanyal, A., W. Allison, "Lessons Learned from SCRExperience ofCoal-Fired Units in Japan, Europe and USA; Are These Enough?" Presented at the 2002 DOE Conference Selective Catalytic Reduction andNon Catalytic Reduction for NOx Control, Pittsburgh, PA, May 2002.
A- 54Sargent & Lundy Engineers Engineering Data, Unit 1 Baldwin Power Station. IPPRO0085676-744. Sargent and Lundy, LLC, "Application ofSCRTechnology to North Dakota Lignite Fuels", a Power Point presentation, May 2007. Selective Catalytic Reduction for Coal-Fired Power Plants: Feasibility and Economics, EPRI CS-3603, October 1984. Smith, R, J. Bennett, D. Broske, "Impacts ofTexas Lignite on SCR Catalyst Life and Performance", presented at the 2007 EPRI SCR Workshop in Pensacola, Florida, November 2007. S02 and NOxAbatement for Stationary Sources in Japan. 1. Ando. U.S. EPAlIERL, EPA600/7-83-028, May 1983. Sobolewski, H, H. Hartenstein, H. Rhein, "STEAG's Long Term SCR Catalyst Experience and Cost", The 2005 EPRI Workshop on Selective Catalytic Reduction, Louisville, KY, November 2005. State ofNorth Dakota, Department ofHealth, Division ofAir Quality, Air Pollution Control Title V Permitto Operate, PermitNumber T5-X78001 issued on 7/31/2006. Summary ofResponses to EPA/DOH Questions on Minnkota Power's NOx BACT Analysis for Milton R. Young Units 1 & 2, Presentation by EERC, Minnkota Power, Burns & McDonnell to NDDH and U.S. EPA, May 23, 2007. Tangential Low NOxSystem at Reliant Energy's Limestone Unit 2 Cuts Texas Lignite, PRB and Pet Coke NOx , Ron Pearce, Reliant Energy and John Grusha, Foster Wheeler Energy Corporation, May 30, 2001. Technical Assessment ofNOx Removal Processes for Utility Application. EPA-600/7-77- 127, November 1977. Technical Feasibility and Cost ofSCRNOx Control in Utility Applications, RP 1256-8 prepared by United Engineers and Constructors, Inc. for Electric Power Research Institute (EPRI), August 1989. 

### "Top-Down"BestAvailable Control Technology Guidance Document (Mar. 15, 1990). Office ofAir Quality Planning and Standards, U.S. EPA. Twenty-five Years ofSCR Evolution: Implications for US Application and Operation, Cichanowicz and Muzio, 2001.

A- 55Yurkanin, T., H,-V. Hartenstein, "O&M Cost Savings Through SCR Management and CatalystRegeneration for the Logan Generating Plant", apaperpresented atthe 6th Annual Electric Power Conference & Exhibition,Baltimore, MD, 2004.

A-56

### Appendix B: SCRVendor Query Correspondence
1. Vendor Correspondencewith SCR system suppliers 1.1 E-Mail correspondence with Clay Erickson, BabcockPower (SCR System Vendor

- extensive tail-end SCRexperience) From: cerickson@babcockpower.com [mailto:cerickson@babcockpower.com] Sent: Thursday, June 19, 2008 15:59 To: Hans Hartenstein Cc: jlangone@babcockpower.com; tlicata@babcockpower.com Subject: Re: Tail-end SCR Hans, Babcock Power has reviewed the Milton Young plant in the past, based on these reviews Babcock Powerfinds o A tail-end SCR is technically and commercial feasible o Babcock Power does not recommend or require additional pilot testing only properflue gas characterization as with any SCR system per performed o Will provide commercial guarantees for the SCR and catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime Babcock Power has the largest SCR experience list in the world; from this experience we are completely confident in the application of a tail end system at Milton Young. Ifyou have further questions please let me know. With best regards, Clay Clayton Erickson, PhD Director, Process Engineering Babcock Power Inc. 5 Neponset Street Worcester, MA 01606 T: 508-854-4039 F: 508-854-1177 M: 508-245-2383

From: "HansHartenstein"<Hans.Hartenstein@Evonik-EnergyServices.us> Sent: 06/18/2008 12: 16 To: <cerickson@babcockpower.com> SUbject: Tail-end SCR Clay, As discussed during our phone conversation today, during which you stated that Babcock Power considers a high-dust SCR principally, technically feasible even though not without technically resolvable challenges for Minnkota's Milton R. Young Station, I would also be interested in Babcock Power's position'on the technical feasibility of a tail-end SCR (downstream of a wet scrubber including
A- 57flue gas reheat) Given your knowledge about the plant (cyclone-fired B&W boilers, ESP, wet scrubber) and the fuel (ND lignite), would Babcock Power: Consider a tail-end SCR technically feasible? Recommend or require additional pilot testing? Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime? If so what would these be? Given the fact that tail-end SCRs in Germany including the ones built by your licensor Fisia Babcock (most ofwhich are on wet bottom boilers) went into operation in the late 1980s and most ofthem still operate on the initial fill of catalyst after almost 20 years and up to 130,000 operating hours, I would assume that Babcock Power 1Fisia Babcock has sufficient confidence in yourtail-end SCR experience to competently respond to these questions. Please let me know ifyou have any additional questions. Thanks. Best regards, Hans Hartenstein


### 1.2 E-Mail Correspondence with Don Tonn, Babcock & 

### Wilcox (SCR System Vendor

- no tail-end SCRexperience) From: Tonn, Donald P [mailto:dptonn@babcock.com] 

### sent: Monday, June 23, 2008 16:06 To: Hans Hartenstein Subject: RE: Tail-end SCR Hans: Please note my responses to your questions in the referenced email below. Regards, Donald P. Tonn Babcock & Wilcox Power Generation Group AQCS Technology Phone 330-860-1986 Cell 330-289-7795

From: Hans Hartenstein [mailto:Hans,Hartenstein@Evonik-EnergyServices.us] 

### sent: Wednesday, June 18, 2008 13:25 To: Tonn, Donald P Subject: Tail-end SCR Don, As discussed during our phone conversation today, during which you stated that Babcock &Wilcox considers a tail-end SCR (downstream of a wet scrubber including flue gas reheat) principally technically feasible for Minnkota's Milton R. Young Station, I would be interested in Babcock & Wilcox's position on the following questions. Given your knowledge about the plant (cyclone-fired B&W boilers, ESP, wet scrubber) and the fuel (ND lignite), would Babcock & Wilcox: Consider a tail-end SCR technically feasible? Yes Recommend or require additional pilot testing? Requires further discussion with catalyst suppliers. 

### A-58Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime? If so what would these be? While B&W has considered tail-end SCR systems on other projects we have not had these commercial guarantee discussions with the catalyst suppliers for the North Dakota lignite application. Before consideration of providing these guarantees a comfort level would be required after obtaining guarantees from catalyst suppliers. Given the fact that tail-end SCRs in Germany went into operation in the late 1980s and most ofthem still operate on the initial fill of catalyst after almost 20 years and up to 130,000 operating hours, I would assume that Babcock & Wilcox has sufficient confidence in tail-end SCR systems to competently respond to these questions. Please let me know ifyou have any additional questions. Thanks. Best regards, Hans Hartenstein



### 2. Vendor Correspondence with SCR CatalystManufacturers
2.1 E-Mail Correspondence with Cindy Khalaf, Argillon (Catalyst Manufacturerextensive tail-end SCR experience)

From: Khalaf Cindy R [mailto:cindy.khalaf@argillon.com] 

### Sent: Tuesday, June 24 2008 14:15 To: Hans Hartenstein Subject: Re: Argillon Tail-end SCR No problem. Regards, Cindy

From: Hans Hartenstein <Hans.Hartenstein@Evonik-EnergyServices.us> Sent: Tuesday, June 24,2008, 16:45 To: Khalaf Cindy R Subject: RE: Argillon Tail-end SCR Cindy, Thanks a bunch for taking the time to respond. I greatly appreciate your answer. I'll keep you posted where this thing is going. Best regards, Hans Hartenstein http://www.evonik-energyservices.us

From: Sadler Randy rmailto:randy.sadler@argillon.coml Sent: Tuesday, June 24,200808:15 AM
A- 59To: Hans Hartenstein Cc: Khalaf Cindy R Subject: Argillon Tail-end SCR Importance: High On behalf of Cindy Khalaf
- Hans, Further to our phone call, as far as I know, Argillon has more tail end experience than any other SCR catalyst manufacturer and, as you noted, we also have experience with high dust, German lignite SCRs. Argillon also won the first US lignite SCR catalyst project (Luminant Oak Grove 1 & 2) and provided commercial guarantees. These units are not in service yet. So, yes, we consider ourselves able to answerthese questions competently. Consider a tail-end SCR technically feasible? Yes, we consider this configuration to be technically feasible. As you know, tail end SCRs are often used when there are significant catalyst poisons in a flue gas stream. A wet scrubber can remove most ofthese poisons, resulting in very low catalyst deactivation. Recommend or require additional pilot testing? For a high dust configuration, we would say definitely. For a tail-end configuration, we would say no. We would only like to see a flue gas analysis for conditions at the inlet to the SCR in order to predict deactivation rate. Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime? If so what would these be? Generally speaking, yes, we would provide guarantees for DeNOx & slip as specified (not to exceed 90% or 2 ppm), 24k hours life, S02 conversion rate - low but value TBD, pressure drop
- value TBD. Ofcourse we would have to see the technical specifications before being more specific. In addition, tail-end SCRs perform much longer, so depending on the application specifics, customer, etc., we may decide to extend the operating life guarantees. This is a commercial decision and will be reviewed on a case-by case basis. Ifyou have any more questions, please let me know. Regards, Cindy Cindy R. Khalaf Argillon LLC President Tel: 678.341.7520 Mobile: 770.331.9571 FAX: 678.341.7509 Email: cindy.khalaf@argillon.com 5895 Shiloh Road, Ste. 101 Alpharetta, GA 30005

From: Hans Hartenstein [mamo: Hans. Hartenstein@Evonik-EnergyServices.us] Sent: Thursday, June 19, 2008 16:29
A-60To: Khalaf Cindy R Subject: Tail-end SCR Cindy, As discussed during our phone conversation today, during which you stated that Argillon considers a high-dust SCR principally technically, feasible based on your high-dust SCR experience with lignite fired units in Europe even though not without technically resolvable challenges for Minnkota's Milton R. Young Station, I would also be interested in Argillon's position on the technical feasibility of a tailend SCR (downstream of a wet scrubber including flue gas reheat). Given your knowledge about the plant (cyclone-fired B&W boilers, ESP, wet scrubber) and the fuel (NO lignite), would Argillon: Consider a tail-end SCR technically feasible? Recommend or require additional pilot testing? Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime? If so what would these be? Given the fact that tail-end SCRs in Germany including the ones equipped with Argillon catalyst went into operation in the late 1980s and most ofthem still operate on the initial fill of catalyst after almost 20 years and up to 130,000 operating hours, I would assume that Argillon has sufficient confidence in yourtail-end SCR experience to competently respond to these questions. Please let me know ifyou have any additional questions. Thanks. Best regards,

. Hans Hartenstein


### 2.2 E-Mail Correspondence with John Cochran, CERAM Environmental (Catalyst Manufacturer

- extensive tail-end SCRexperience) From: John Cochran [mailto:John.Cochran@ceram-usa.com] 

### sent: Wednesday, June 25, 2008 15:14 To: Hans Hartenstein Cc: Greg Holscher; Noel Rosha; Orehovsky Kurt Subject: RE: Request for Information Hans, CERAM certainly considers the use of atail-end SCR on applications such as the Milton R. Young Station as technically feasible provided a proper design approach is used. CERAM has the experience from more than 100 tail-end and low dust applications dating from 1988 that would substantiate our opinion. For atail-end approach we see no need for additional pilot testing. As such, we can provide full commercial guarantees for catalyst performance (activity or lifetime, conversion rate, pressure drop, etc.). The choice between high dust and tail-end processes certainly should consider capital costs, operating costs and process risk. Based on our experience certainly process risk would favor atailend approach, but albeit for most circumstances at a higher "all-in" cost. Should very high retrofit factors be present for a high dust arrangement then the relative economic factors may even favor a tail-end approach. I hope this information is useful to your evaluation. Please advise should you have any further A- 61questions or information needs. Thanks. Best Regards, John Cochran CERAM Environmental, Inc. www.frauenthal.net 913.239.9896 (phone) 913.205.5615 (cell) This e-mailandanyattachments are confidential. If you have receivedthis electranic transmission in error, please reply to the sender regarding the errorandpermanentlydelete the originalmessage andanyattachments.

From: Hans Hartenstein [mailto:Hans.Hartenstein@Evonik-EnergyServices.us] sent: Tuesday, June 17, 2008 7:20 To: John Cochran 

### Subject: Request for Information John, As discussed during our phone conversation today, during which you stated that CERAM considers a high-dust SCR principally technically, feasible even though not without technically resolvable challenges for Minnkota's Milton R. Young Station, I would also be interested in CERAM's position on the technical feasibility of a tail-end SCR (downstream of a wet scrubber including flue gas reheat) Given your knowledge about the plant (cyclone-fired B&W boilers, ESP, wet scrubber) and the fuel (ND lignite), would CERAM: Consider a tail-end SCR technically feasible? Recommend or require additional pilot testing? Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime? If so what would these be? Given the fact that tail-end SCRs in Germany including the ones equipped with CERAM catalyst (Herne 1, 2 and 3, Voerde (West) 1 and 2, LOnen 10 and 11
- all ofwhich are wet bottom boilers) went into operation in the late 1980s and most ofthem still operate on the initial fill of catalyst after almost 20 years and up to 130,000 operating hours, I would assume that CERAM has sufficient confidence in yourtail-end SCR experience to competently respond to these questions. Please let me know ifyou have any additional questions. Thanks. Best regards, Hans Hartenstein


### 2.3 E-Mail Correspondence with ScotPritchard, Cormetech (Catalyst Manufacturer

- no tail-end SCR experience)
From: Pritchard, Scot G. [mailto:PritchardSG@Cormetech.com] Sent: Thursday, June 19, 2008 17:41 To: Hans Hartenstein Subject: RE: Tail-end SCR Hans,
A- 62I was thinking of ifyou put a coupon in the tailend location and it showed something weird then you would have to do something more elaborate Le. A slipstream with longer hours, etc. We do not anticipate this
- in fact you could probably do without the coupon test as well since I don't see any reason why this system would be any different the primary tail end experience i.e. Unlikely any nasties make itthrough the lowertemperature environment and scrubber process. The coupon is OK but I really don't expect to see much. Finally, we have not done any specific coupon tests (because slipstream has been the primary way to evaluate) so we would need to think through the best way to do it
- Le. holder, mounting arrangement, test method, hours of exposure, etc. Ifyou already have something in mind please let uS know. Hope that helps with the clarification. Scot

From: "Hans Hartenstein" <Hans.Hartenstein@Evonik-EnergyServices.us> Sent: Thursday, 6/19/084:26 pm To: "Pritchard, Scot G." <PritchardSG@Cormetech.com> Subject: RE: Tail-end SCR Scot, Thanks for the input from Cormetech, which is greatly valued. One question for clarification purposes only, though. Coupon tests and/orflue gas analysis would only be performed in order to characterize the flue gas going into the tail-end SCR as is needed for the design of any APC equipment. Obviously, nobody could offer any performance guarantees concerning what's coming out of a tail-end SCR without knowing what's going into it. You state that in case coupon tests would show a significant accumulation of catalyst poisons, a subsequent slip stream test, which is unquestionably more accurate and representative of a full scale
- in this case tail-end
- SCR, would be recommended. Stating this, do I understand you right that you would recommend this slip stream testing mainly for the purpose of properly characterizing the flue gas composition at the inlet to the tail-end SCR in orderto provide a reliable basis for correct catalyst design? Do I assume correctly, that you would not require extensive and long-term (12
- 24 months) pilot testing with a slip stream reactor because you have serious doubts about the principal technical feasibility of a tail-end SCR forthis application? Please clarify. Thanks. Best regards, Hans Hartenstein

From: Pritchard, Scot G. [mailto:PritchardSG@Cormetech.com] Sent: Thursday, June 19, 2008 12:15 To: Hans Hartenstein Subject: RE: Tail-end SCR Hans, Please see my input below. As discussed during our phone conversation today, during which you stated that Cormetech considers a high-dust SCR principally technically, feasible even though not without technically resolvable challenges for Minnkota's Milton R. Young Station, I would also be interested in Cormetech's position on the technical feasibility of a tail-end SCR (downstream of a wet scrubber including flue gas reheat) Given your knowledge about the plant (cyclone-fired B&W boilers, ESP, wet scrubber) and the fuel (ND lignite), would Cormetech: Consider a tail-end SCR technically feasible?
- yes A- 63Recommend or require additional pilot testing?
- We generally do not consider coupon testing an accurate representation of an SCR, however in orderto minimize cost and provide basic screening information we would suggest the potential use of a coupon sample test. Ifthe coupon shows significant accumulation of catalyst poisons, a subsequent slipstream type test which is more representative of a full scale SCR i.e match velocity, AVs, etc. would be recommended. Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime? If so what would these be? Presuming the coupon test does not shoW anything unusual (which we do not expect to see anything unusual) we would be willing to provide commercial guarantees for a low dust application. Basic guarantees would be associated with life (this would not include specific Ko and KlKo as guarantees - the guarantee would be an efficiency and slip guarantee at a certain number of operating hours ), S02 conversion, pressure loss. As discussed, the high dust application needs additional due diligence testing (slipstream, ash testing, etc.) as well as the practicality ofthe applicable operating temperature to establish the commercial stance for a high dust application on North Dakota Lignite. We have done such work for Texas lignite as well as other coal sources and otherfuels/applications in the past and would expect to be able to achieve the same for this application. The economics for any given application would be considered on a case by case basis. Let me know ifyou have any questions. Also I would appreciate anything ofthe final document that you can share. Thank you and regards, Scot Pritchard VP, Sales & Marketing Cormetech 919-595-8708 0 919-815-2380 c
Frain: Hans Hartenstein [mailto:Hans.Hartenstein@Evonik-EnergyServices.us] 

### sent: Thursday, June 19, 2008 11:35 AM To: Pritchard, Scot G. Subject: Tail-end SCR Scot, As discussed during our phone conversation today, during which you stated that Cormetech considers a high-dust SCR principally technically, feasible even though not without technically resolvable challenges for Minnkota's Milton R. Young Station, I would also be interested in Cormetech's position on the technical feasibility of a tail-end SCR (downstream of a wet scrubber including flue gas reheat) Given your knowledge about the plant (cyclone-fired B&W boilers, ESP, wet scrubber) and the fuel (NO lignite), would Cormetech: Consider a tail-end SCR technically feasible? Recommend or require additional pilot testing? Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion rate) and lifetime? If so what would these be? Given the fact that tail-end SCRs in Germany (most ofwhich are on wet bottom boilers) went into operation in the late 1980s and most ofthem still operate on the initial fill of catalyst after almost 20 years and up to 130,000 operating hours, I would assume that Cormetech has sufficient confidence in tail-end SCR systems to competently respond to these questions. Please let me know ifyou have any additional questions. Thanks.
A- 64Best regards, Hans Hartenstein


### 2.4 E-Mail Correspondence with Flemming Hansen, HaldorTopsoe (Catalyst Manufacturer

- extensive tail-end SCR experience) From: Flemming Hansen [mailto:FGH@topsoe.com] sent: Friday, June 27, 2008 12:56 To: Hans Hartenstein Subject: RE: Tail-end SCR Hans, Your understanding is what I meant to say. Thanks Flemming G. Hansen Manager SCR DeNOx Catalyst HaldorTopsoe, Inc. 281-228-5120 (office) 281-228-5129 (fax) 281-684-8820 (cell) FGH@Topsoe.com www.topsoe.com

"Hans Hartenstein"<Hans.Hartenstein@EvonikEnergyServices.us> 06/24/2008 04: 16 PM

Flemming, To "Flemming Hansen" <FGH@topsoe.com> cc Subject RE: Tail-end SCR

Thanks for your note. Just to make sure that I understand you correctly. Is it correct to state that HaldorTopsoe feels fully confident that a tail-end SCR is technically feasible and would not experience any accelerated catalyst deactivation? Therefore, you would be willing to guarantee catalyst performance (NOx removal efficiency, pressure drop, S02/S03 conversion rate and catalyst lifetime) without any need for further pilot testing. Please confirm. Thanks. Best regards, Hans Hartenstein

From: Flemming Hansen [mailto:FGH@topsoe.com] Sent: Dienstag, 24. Juni 200816:44 To: Hans Hartenstein


### A-65Subject: Re: Tail-end SCR Hans, Like you describe we have had very good operating experience with SCR in the clean environment after a scrubber or bag filter. There appears to be practically no catalyst deactivation and with the low amount of particulate the catalyst pitch can be small, which both leads to a compact SCR as compared to a high dust SCR. Based on the clean flue gas afterthe FGO we would not require any further testing in orderto guarantee a catalyst performance. The actual guarantees would be as normally applied in a high dust installation and depend on the catalyst volume and operating conditions. At the low operating temperature expected at the tail-end position the S02 oxidation will be negligible. I hope this confirmation will have your approval. Flemming G. Hansen Manager SCR OeNOx Catalyst HaldorTopsoe, Inc. 281-228-5120 (office) 281-228-5129 (fax) 281-684-8820 (cell) FGH@Topsoe.com www.topsoe.com

"Hans Hartenstein" <Hans.Hartenstein@EvonikEnergyServices.us> 06/24/2008 10:24 AM Flemming, To <fgh@topsoe.com> cc Subject Tail-end SCR

As discussed during our phone conversation today, during which you stated that Haldor Topsoe considers a high-dust SCR principally technically, feasible even though not without technically resolvable challenges for Minnkota's Milton R. Young Station, I would also be interested in Haldor Topsoe's position on the technical feasibility of a tail-end SCR (downstream of a wet scrubber including flue gas reheat) Given your knowledge about the plant (cyclone-fired B&W boilers, ESP, wet scrubber) and the fuel (NO lignite), would HaldorTopsoe: Consider a tail-end SCR technically feasible? Recommend or require additional pilot testing? Be willing to provide commercial guarantees for catalyst performance (activity, pressure drop and S02/S03 conversion**rat~)** and lifetime? If so what would these be? Given the fact that tail-end SCRs in Germany including the ones equipped with your catalyst have been in operation since the late 1980s and most ofthem still operate on the initial fill·of catalyst after almost 20 years and up to 130,000 operating hours, I would assume that HaldorTopsoe has sufficient confidence in yourtail-end SCR experience to competently respond to these questions. Please let me know ifyou have any additional questions. Thanks.
Best regards, Hans Hartenstein 

### A-66

### Appendix C: Selected Papers Authored in Last Ten Years
Selected SCR related papers in English I have authored in the lastten years: Licata, A., W. Schiittenhelm, H. Hartenstein, "Mercury and Dioxin Control for Municipal Waste Combustors", Asia-North American Waste Management Conference, Los Angeles, CA, USA 1998. Hartenstein, H., P. Dyke, "Working Group 1 Expert Report

- Sources and Technology", 1st Scientific and Evaluation Workshop on Persistent Manufactured Chemicals and ByProducts from Industrial and Combustion Processes, UNEP Chemicals, Geneva, Switzerland 1999. Bouwman, H., H. Hartenstein, "Working Group 

### 2 Expert Report

- Technology and Remediation", 4th Workshop on Policy, Social and Economic Issues Assessing Persistent Toxic Substances, UNEP Chemicals, Geneva, Switzerland 1999. Chandler, J, 1. Gallant, H. Hartenstein, "Retrofit ofa WTE-Facility With SCR for NOx and PCDD/FControl NazS4-lnjection for Mercury Control", 

## i h North American Waste-ToEnergy Conference, Tampa, FL, USA 1999. Hartenstein, H., "Dioxin and Furan Inventories

- National and Regional Emissions of PCDD/PCDF", UNEP Chemicals, Geneva, Switzerland 1999. Hartenstein, H., H. Gutberlet, "Utility Experience with SCR in Germany", DOE Conference on SCRlSNCR, Pittsburgh, PA, USA 1999. Chandler, 1., 

### J. Gallant, H. Hartenstein, A. Licata, "Retrofit ofa WTE Facility with SCRfor NOx and PCDDIF Control and NaZS4 Injection for Mercury Control", DOE Conference on SCRlSNCR, Pittsburgh, PA, USA 1999. Schiittenhelm, W., R. Wemhoner, H. Hartenstein, K. Werner, "Reduction ofPCDD/F Emissions From Iron Ore Sintering Plants

- The First Full-Scale SCR Installation", 19th International Symposium on Halogenated Environmental Organic Pollutants and POPs

- Dioxin 99, Venice, Italy 1999. Gutberlet, H., H. Hartenstein, 

### A. Licata, "SOz Conversion Rate ofDeNOx Catalysts

- Effects on Downstream Plant Components and Remedial Measures", The Mega Symposium

- EPA-DOE-EPRI Combined Power Plant Air Pollution Control Symposium, Atlanta, GA, USA 1999. Hartenstein, H.-U.; Schiittenhelm, W.; "Dioxin and Furan Reduction Technologies for Combustion and Industrial Thermal Process Facilities", Workshop on Polychlorinated Dibenzo-P-Dioxins and Polychlorinated Dibenzofurans, Pollution Control Department, Bangkok, Thailand 1999
A- 67Hartenstein, H. "UNEP's Standardized Dioxin Release Inventory Kit- A Tool to Assist Countries in EstablishingNational 

### PCDD/PCDF Release Inventories", Sub-Regional Expert Meeting on the Reduction ofPersistent Organic Pollutants (POPs) in Particular Dioxins and Furans, St. Petersburg, Russia 1999. Hartenstein, H. "Techniques to Reduce Emissions ofDioxins And Furans From Large Sources", Sub-Regional Expert Meeting on the Reduction ofPersistent Organic Pollutants (POPs) in Particular Dioxins and Furans, St. Petersburg, Russia 1999. Hartenstein, H., "Modem Technologies to Reduce Emissions ofDioxins and Furans from Waste Incineration", International Symposium on Environmental Endocrine Disrupters '99, Kobe, Japan 1999. Fiedler, H., P. Dyke, H. Hartenstein, "Standardized Dioxin Inventory Toolkit" UNEP Chemicals, Geneva, Switzerland 2000. Chandler, J, H. Hartenstein, "Controlling Heavy Metals and Persistent Organic Pollutants from Waste Incineration", Internationales Symposium zurAbfallwirtschaft in Mitteleuropa, Prague, Czech Republic 2000. Hartenstein, H., "Availability ofTechniques to Reduce Non-Pesticide PTS", STAP Brainstorming Meeting on Persistent Organic Pollutants (POPs), Bridgetown, Barbados 2000. Hartenstein, H., "Guidance Document for the Collection, Assembly and Evaluation ofData on Sources, Environmental Levels and ImpactAssessment" GEF: Regionally Based Assessment ofPersistentToxic Substances, UNEP Chemicals, Geneva, Switzerland 2000. Hartenstein, H., "Techniques to Reduce 

### PCDD/PCDF Emissions from Waste Incineration", Invitational Expert

### PCDDIPCDF Workshop sponsored by UNEP Chemicals Switzerland, Gesellschaft fUr Technische Zusammenarbeit Germany and the Thai Pollution Control Department, Bangkok, Thailand 2000. Licata, A., H. Hartenstein, "Modem Technologiesto Reduce Emissions ofDioxins and Furans from Waste Incineration", 8th Annual North American Waste To Energy Conference, Nashville, TN, USA 2000. Hartenstein, H., "Introduction and Use ofTechniques to Reduce Emissions ofDioxins and Furans - A Training Module to Complement UNEP's Standardized Toolkit for Identification and QuantificationofDioxin and Furan Releases", UNEP Chemicals, Geneva, Switzerland 2000. Hartenstein, H. "Techniques to Reduce Emission ofDioxins and Furans", UNEP Workshop on PCBs, Dioxins and Furans, Montevideo, Uruguay 2000. A- 68Fiedler, H., P. Dyke, H. Hartenstein, "Standardized Toolkitto Establish Dioxin Inventories", UNEP Workshop on PCBs, Dioxins and Furans, Montevideo, Uruguay 2000. Fiedler, H., P. Dyke, H. Hartenstein, "Needs and Ways to Establish Complete and Comparable Dioxin Inventories", 20th International Symposium on Halogenated Environmental Organic Pollutants and POPs

- Dioxin 2000, Seoul, Korea 2000. Schluttig, A., P. Servatius, H. Hartenstein, "Lifetime Extension ofSCR-DeNOx Catalysts Using SCR-Tech's High Efficiency Ultrasonic Regeneration Process", DOE Conference on SCR/SNCR, Pittsburgh, Pa, USA 2001. Hartenstein, H., "Final Result Evaluation Report

- Thailand Dioxin Sampling Program November 20,2000

- January 26, 2001", Gesellschaft fUr Technische Zusammenarbeit, Bonn, Germany 2001. Hartenstein, H., A. Schluttig, P. Servatius, "Lifetime Extension ofSCR-DeNOx Catalysts Using SCR-Tech's High Efficiency Ultrasonic Regeneration Process", Coal-Gen, Chicago, II, USA 2001. Hartenstein, H., A. Schluttig, P. Servatius, H. Gutberlet, "Experience with Full Scale Commercial Regeneration ofSCR-DeNOx Catalyst" The Mega Symposium

- EPA-DOEEPRI Combined Power PlantAir Pollution Control Symposium, Chicago, IL, USA 2001. Hartenstein, H., H. Gutberlet, "CatalystRegeneration

- An Integral PartofProperCatalyst Management", The 2001 EPRI Workshop on Selective Catalytic Reduction, Baltimore, MD, USA 2001. Hartenstein, H., "SCR Experience in Europe

- Lessons Learned After 17 Years ofSCR Operation", Invitational SCR Workshop by Babcock & Wilcox, Akron, OH, USA 2002. Bullock, D., H. Hartenstein, "O&M Cost Reduction ofa Coal-Fired US Merchant Plant Through an Optimized SCR Management Strategy Involving Catalyst Regeneration", DOE Conference on SCR/SNCR, Pittsburgh, PA, USA 2002. Fiedler, H., P. Chareonsong, 1. Mayer, H. Hartenstein, 

### "PCDD/PCDF Emissions From Stationary Sources

- First Results From Thailand", 22nd International Symposium on Halogenated Organic & Persistent Organic Pollutants

- Dioxin 2002, Barcelona, Spain 2002. Harrison, K., E. Healy, H. Hartenstein, "Southern Company's Investigation ofCatalyst Cleaning and Regeneration Options", The 2002 EPRI Workshop on Selective Catalytic Reduction, Atlanta, GA, USA 2002.

.

A- 69Craig, M., H. Harrison, E. Healy, H. Hartenstein, "CatalystPluggage Due to Popcorn AshCleaning and Regeneration Options", The Mega Symposium

- EPA-DOE-EPRI Combined Power PlantAir Pollution Control Symposium, Washington, D.C., USA 2003. Bullock, D., H. Hartenstein, "O&M Cost Reduction ofa Coal-Fired US Merchant Plant Through an Optimized SCR Management Strategy Involving CatalystRegenerationStrategy Update Summer 2003", The Stack Emissions Symposium, Clearwater Beach, FL, USA 2003. Bullock, D, H. Hartenstein, "Full-Scale Catalyst Regeneration Experience At The CoalFired Indiantown Generating Plant", DOE Conference on SCR/SNCR, Pittsburgh, PA, USA 2003. Hartenstein, H., "Dioxin and Furan Reduction Technologies for Combustion and Industrial Thermal Process Facilities", HandbookofEnvironmental Chemistry- Volume 3 Anthropogenic Compounds Part 

### 0 - Persistent Organic Pollutants, Springer Verlag Berlin Heidelberg New York, ISBN 3-540-43728-2, Germany 2003. Hartenstein, H. "Performance ofCommonly Used Combustion Technologies on POPs Destruction", STAP/GEF Technical Workshop on Emerging Innovative Technologies for the Destruction and Decontamination ofObsolete POPs, Washington D.C., USA 2003. Hartenstein, H., "Control Technologies for the W. H. Sammis Plant, Stratton, Ohio" Expert Report for the US Department ofJustice, Civil Action No. C-2-99-1181, Washington D.C., USA 2003. Hartenstein, H., "CatalystRegeneration Experience", NOx Round Table 2004 Conference and Exhibit, Akron, OH, USA 2004. Yurkanin, T, H. Hartenstein, "O&M Cost Savings Through SCR Management and Catalyst Regeneration for the Logan Generating Plant", Electric Power2004 Conference and Exhibit, Baltimore, MA, USA 2004. Hartenstein, H., "AirPollution Control Technologies for the W. H. Sammis Plant, Stratton, Ohio developed in connection with United States v. Ohio Edison Company, et at." Expert Rebuttal Report for the US Department ofJustice, Civil ActionNo. C-2-99-1181, Washington D.C., USA 2004. Hartenstein, H., "Incineration Technologies", World Bank Workshop Series: Issues on Waste Disposal: Workshop 1 - Hazardous Wastes, Washington D.C., USA, 2004. Wiese, S., D. Monnin, K. Sauvageau, H. Hartenstein, "O&M Cost Optimized SCR Operation and Management atAES' Somerset Station", The Mega Symposium

- Combined AirPollution Control Symposium, Washington D.C., USA 2004.

A-70Harrison, K, E. Healy, M. Craig, T. Harbin, L. Mays, H. Hartenstein, "Simultaneous Reduction ofthe S02 Oxidation Rate During Catalyst Washing And Regeneration", 2004 EPRl SCR Workshop, Pittsburgh, PA, USA 2004. Hartenstein, H., "Pet Coke

- Effects ofWet and Dry Scrubbing", 2005 WPCA / Dominion Particulate

- Scrubber Seminar, Richmond, VA, USA 2005. Hartenstein, H., "LPA Screens

- Utilities Need a Proven Solution", WPCA News, Issue 8 fall 2005, Chicago, IL, USA 2005 Sobolewski, H, H. Hartenstein, H. Rhein, "STEAG's Long Term SCR Catalyst Experience and Cost", The 2005 EPRl Workshop on Selective Catalytic Reduction, Louisville, KY, USA 2005. Hartenstein, H., "LPAScreens - A Proven Solution", 2006 NOx Round Table Conference and Expo, Charlotte, NC, USA 2006 Hartenstein, H., "SCR Management Ensures SCR Performance at Minimum Operating Cost", WPCA News, Issue 9 spring 2006, Chicago, IL, USA 2006 Sobolewski, H., H. Hartenstein, M. Martin, "STEAG's Long Term SCR Catalyst Experience and Cost", DOE-NETL Conference on SCRlSNCR, Pittsburgh, PA, USA 2006 Martin, M., M. Harrell, J, Jancauskas, H. Hartenstein, H. Sobolewski, "Large Particel Ash (LPA) Screen Retrofits at Coal-Fired Units in Indiana and Ohio", DOE-NETL Conference on SCRlSNCR, Pittsburgh, PA, USA 2006 Hartenstein, H., "SCR Operating and Management Experience Including Catalyst Regeneration", AES Operator's Meeting, Denver, CO, USA 2006 Hartenstein, H., "AIG Tuning

- An Essential Part ofSCR Management", WPCA News, Issue 10 fall 2006, Chicago, IL, USA 2006 Rhein, H., S. Sobolewski, H. Hartenstein, M. Martin, "STEAG's Long-Term Catalyst Operating Experience and Cost", Power Plant Air Pollutant Control Mega Symposium, Baltimore, MD, USA 2006 Harrell, M., J. Jancauskas, H. Hartenstein, S. Sobolewski, M. Martin "LPA Screen Retrofits at Coal-Fired Units in Indiana and Ohio", Power Plant Air Pollutant Control Mega Symposium, Baltimore, MD, USA 2006 Rhein, H., H. Hartenstein, H. Brilggendick, "Cost Development ofSingle Absorber Open Spray Tower LSFO FGDs During the Last 20 Years

- STEAG's Experience", Power Plant AirPollutant Control Mega Symposium, Baltimore, MD, USA 2006.

A-71Hartenstein, H., S. Wiese, M. Martin, "Regeneration

- STEAG Process and Experience", The 2006 EPRI Workshop on Selective Catalytic Reduction, Dearborn, MI, USA 2006 Martin, M. H. Hartenstein, "Bench Scale Testing ofCatalyst

- History and Protocol", The 2006 EPRI Workshop on Selective Catalytic Reduction, Dearborn, MI, USA 2006 Hartenstein, H., "German Experience With CatalystRegeneration", 2007 NOx Round Table Conference and Expo, Cincinnati, OH, USA 2007 Hartenstein, H., "STEAG's Catalyst Regeneration Process

- Ten Years ofExperience", 2007 NOx Round Table Conference and Expo, Cincinnati, OH, USA 2007 Martin, M., H. Hartenstein, "Catalyst Bench Scale Testing: Guidelines and Round Robin Testing", WPCA News, Issue 11 spring 2007, Chicago, IL, USA 2007 Elliot, P., Hartenstein, H., "Selective Separation ofMercury and Other Heavy Metals During FGD Wastewater Treatment"", 2007 APC Round Table Conference and Expo, Chattanooga, TN, USA 2007 Elliot, P., H. Hartenstein, "A Cost Effective FGD Wastewater Treatment System" WPCA News, Issue 12 fall 2007, Chicago, IL, USA 2007 Kramer, M., C. Gerlach, H. Hartenstein, "As203 and S03 Testing at Hoosier Energy's Merom Generating Station", The 2007 EPRI Workshop on Selective Catalytic Reduction, Pensacola, FL, USA 2007



### A-72

### Appendix D: Resume 

# Hans-Ulrich H art ens t e i n

Title: Managing DirectorE&EC Nationality: German
Education:

• University ofStuttgart

• University ofStuttgart

• University ofFlorida

• University ofToronto
General Experiences: B. Sc. in Mechanical Engineering M.E. in Mechanical Engineering M.E. in Environmental Engineering Global Executive MBA

Mr. Hartenstein has been in the**envirom~ental** field for overtwenty years. His experience includes projectdevelopment, projectmanagement and supervision, coordination and implementation ofdesign and building projects for municipal waste-to-energy, hazardous waste incineration, and air pollution control facilities (SCR, FGD, Hg control, 

### PCDD/PCDF control) in the power utility industry and waste-to-energy industry. His responsibilities included project development, process engineering and management, procurement and construction supervision, start-up and commissioning, environmental and financial analysis, permitting application procedures and regulatory interfacing. Mr. Hartenstein has been project management director ofnumerous airpollution control systems, one municipal waste-to-energy project, and four hazardous waste incineration projects. He has been involved in the development ofeighteen environmental projects out of which seven also included permitting procedures and process design, two also included construction and one included complete start-up and commissioning. Mr. Hartenstein has also directed development ofwaste management and airpollution control segments and managed a 

### $ 61 million turnkey contract for 80 TPD hazardous waste incineration contract including a tail-end SCR. After completion ofthe facility Mr. Hartenstein was responsible for the initial 2 years ofoperation ofthe plant. He was also responsible for the successful negotiations ofeight tum key mass bum, waste-to-energy contracts valued in excess of

### $ 600 million and he has successfully negotiated several international airpollution control technology licenses (SCR and FGD) among Polish, 

### A-73Korean, American and Japanese companies. He has managed and supervised feasibility analysis, conceptual engineering and design, permitting final design, technology development, and project implementation and has assisted in project financial planning including assuring financing for several projects. Since 

### 1999 Mr. Hartenstein has been active mainly in the U.S. in the areas ofSCR and FGD retrofits to fossil fuel fired electric utility generating stations. He expanded his initial focus on the design and construction ofthese SCR and FGD retrofits quickly into the areas oflong term operation and maintenance ofairpollution control equipment. His currentfocus is on most cost effective long term FGD and SCRmanagement ensuring maximum performance at the lowest possible cost.
Positions Held:

• Environmental EngineerL&C SteinmUller GmbH!)

• SeniorEnvironmental Engineer L&C SteinmUller GmbH!)

• Engineering DepartmentManagerL&C SteinmUller GmbH!)

• SeniorEngineering DirectorL&C SteinmUller GmbH!)

• Project Management Director L&C SteinmUller GmbH!)

• Plant Manager RVA Bohlen RVA Bohlen GmbH

• SeniorVice President Babcock Borsig Power, Inc.2)
• President SCR-Tech LLC

• President Evonik Energy Services LLC3)
• Managing DirectorE&EC GmbH 

### 1987

- 1989 1989 -1990 1990-1992 1992 -1995 1995

- 1997 1997 -1999 2000

- 2001 2001- 2005 2006

- present 

### 1999

- present
I) L&C Steinmiiller GmbH has been acquired and renamed to Fisia Babcock GmbH 2) Babcock Borsig Power, Inc. has been acquired and renamed Babcok Power, Inc. 3) Steag LLC was renamed Evonik Energy Services LLC, no change in ownership
Professional Memberships

• Member ofthe World Pollution Control Association (WPCA)

• Invitational member ofthe Scientific Technical Advisory Panel (STAP) ofthe United Nations EnvironmentProgramme related to POPs and PTS.



### A-74

## ENCLOSURE 2 EPA COMMENTS ON NDDH PRELIMINARY BACT DETERMINATION

### EPA COMMENTS ON NDDH PRELIMINARY BACT DETERMINATION

I. NDDH'S ANALYSIS OF TECHNICAL FEASIBILITY OF TAIL-END AND LOW-DUST SCRAT MRYS IS INCORRECT AND BASED ON INCOMPLETE INFORMATION. In previous comment letters, EPA explained thatthe applicability ofSCR downstream ofpollution control equipment (tail-end SCR (TESCR) orlow-dust SCR (LDSCR» would effectively eliminate the catalystplugging and deactivationproblems described inthe Minnkota BACT analysis andthatthe costs associated withplant modifications and flue gas reheat in order achieve proper catalyst operating temperatures are a matter ofcost and not technical feasibility. \ B&McD's response to EPA's comments was thatthe information provided by the Energy & Environmental Research Center (EERC) shows that, "effective solutions to prevent orremove micropore pluggage and blinding ofSCR catalyst from sodium-sulfur compounds evident inthe flue gas stream exhausted from a North Dakota lignite-fired boiler, whether installed in a conventional hot-side orcold-side application downstream ofa wet scrubber, have notbeen developed by SCR catalystvendors" and that, "these are credible arguments that adequately describe the reasons thatprecludethe successful deployment ofthis technology onthe cyclone boilers atMRYS.,,2 B&McD does not agree that an economic analysis would be required because, "[t]he extensive plant modifications anticipatedto deploy SCRatUnit 1 and Unit2 

### at MRYS still do notresolve the catalystmicropore plugging andblinding problems evidentinthe Coyote Stationpilotscale testing.,,3 EERC adds that, "[t]here is evidence ofsodium, potassium, calcium, and sulfur deposition downstream ofthe ESP as illustrated in Figure 1 presented inresponse to ERC Core Issue number 

### 2.,,4 Based on these responses, it appears thatthe basis for Minnkota's assertion thatTESCR and LDSCR are teChnically infeasible is solely basedthe perceived catalystmicropore plugging and deactivation problems extrapolated from the results ofthe Coyote Station pilot testing andthe flue gas sampling performed on MRYS Unit 1 downstream ofthe electrostatic precipitator at 3000 

### F.

.The NDDH BACT determination states thatthe site constraint and flue gas reheat issues are a matter ofeconomicsinstead oftechnical feasibility, but "catalystdeactivation of a low-dustortail-gas SCR due to alkali compounds is an issue that will require extensive research, design and pilottesting to determine whetherthe technology can be successfully appliedto units fired on North Dakotalignite. Therefore, these technologies are not
1 See EPA's January 9, 2007 letterto NDDH (sent via fax), pages 13-16 and October4,2007 letterto NDDH and Minnkota, pages 31-35. 2 See Minnkota's November 9, 2007 letterto NDDH, page A-28. 3 See Minnkota's November 9, 2007 letterto NDDH, page A-29. 4 See Minnkota's November 9,2007 letterto NDDH, page A-29. Figure I shows a "Cross-section ofa surface exposed to flue gas at about 3000 F in MRY Unit 1" and the relative weightpercentages ofsodium, silicon, sulfur, potassium, calcium, and iron.EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS

. . 

### considered applicable and nottechnically feasible atthis time."s,6 The NDDH BACT determination cites the sampling provided in Minnkota's November 9,2007 letter which showed weightpercentages ofvarious compounds collected downstream ofthe electrostatic precipitator and previous·experierlce at the Minn-DakFarmer's Coop. coal-fired facility, which hadproblems maintaining compliance with a particulate limit and subsequently had to limittheir fuel sodium content.7 

### As more fully set forth below, Minnkotahas failed to produce sufficient evidence to showthat TESCRorLDSCRwould experience extreme

.catalyst deactivation that would preclude the successful operation at MRYS. 

### Coyote StationPilot Testing Minnkota cites the Coyote Station pilottesting results as they relate to catalyst deactivation and plugging caused by sodium compounds and other alkali compounds as evidence that MRYS wouldnot be suitable for a TESCR orLDSCR installation. This assertion is completelyunfounded for a number ofreasons. First, as described inprevious EPA comment letters and as supplemented

## by the expert opinion report ofMr. Hartenstein provided herein, the Coyote Stationpilottesting was clearly flawed and does not even provide meaningful conclusions to apply to

# afull-scale installation ofhigh-dust SCR (HDSCR). Furthermore, since the Coyote Station pilottesting used flue gas upstream ofthe pollution control equipment, there is even less reason to believe thattest results (even the qualitative results expounded on by Minnkota) have any relevance to a TESCR or LDSCR application, which would have substantially less ash constituents downstream ofan

5 See NDDH BACT detennination, pages 56-57. 6 The NDDH has made the detennination that SCRwould be technically feasible in its analysis ofthe WestmorelandPower, Inc. Gascoyne 500 Generating Station. In its May 2007 analysis ofthe Gascoyne 500 project, the NDDH states, "[b]y reheating the flue gas and locating the SCRdownstream ofthe other air pollution control devices, SCR appears to be technically feasible. However, the Department is not certain thatthis technology will work with a Dakota lignite-fIred unitbecause ithas not beenused before

.. Forthese reasons, the Department retained, with reservations, it as a technologically feasible control option." (See pages 58-59.) This proposed

.project would consist oftwo 285 MW-gross circulating fluidized bed boilers controlled by a dry scrubber and baghouse. The SCR would be located downstream ofboth control devices. In this case, the applicant (Westmoreland) cited many ofthe same concerns stated by Minnkota and the NDDH regarding uncertainty with North Dakota lignite and the signifIcant engineering involved in applying SCRto this facility (Westmoreland even cited the EERC report on the pilottesting at Coyote Station), but concludedlow-dust SCR was still technically feasible. In their pennit application, Westmoreland states, "it is likely that Westmoreland would incur signifIcant engineering and testing to ensure the viability ofa low-dust SCR control system on a lignite-fIred CFB boiler. However, there does not appearto be any technical basis to exclude low-dust SCR from the BACT detennination." Apparently, the NDDH agrees with Westmoreland thatthe signifIcant engineering and testing does notpreclude technical feasibility AND agrees with Minnkota who believes that such activities do preclude technical feasibility. Low-dust SCR was eventually eliminated from consideration for mainly economicreasons, primarily due to the low uncontrolled NOx emissions from the Gascoyne boilers. While the confIguration in the Westmoreland detennination is referred to as low-dust SCR, it should be considered tail-end SCR, as it is downstream ofa both a particulate control device and S02 scrubber. 7 See NDDH BACTdetennination, pages 55-56. 

### -2-EPA Comments onNDDH Preliminary NOx BACTDetermination for MRYS


### electrostatic precipitator (for LDSCR) andwet scrubber (TESCR). Thus, the Coyote Station pilottesting did not provideany meaningful data interms ofevaluating HDSCR and is even less useful for evaluating technical feasibility ofTESCR and LDSCR. MRYS Unit 1 Sampling Minnkota's November 9, 2007 letter, which is cited in the NDDH BACT determination, explains that flue gas sampling ofMRYS Unit 1 was conducted downstream ofthe electrostatic precipitator and a cross-sectional analysis ofthe constituents was performed. Minnkota andthe EERC asserts that the sampling shows a high degree of sulfatedpotassium and sodium compounds similarto the compounds observed atthe Coyote Station pilottest. Therefore, Minnkotabelieves thatthe electrostatic precipitatorwould not remove much ofthe vaporized sodium andpotassium andimplies that similarresults would have beenproduced during the Coyote Stationpilottest ifconducted doWnstream ofthe electrostatic precipitator. Aside from the factthat the Coyote Station pilottesting had significantdesign and operational problems, the results ofthe flue gas sampling presented in Minnkota's November 9, 2007 letter in no wayquantifies the total amount ofparticulate material thatwas collected and would be expected to exist in a LDSCRenvironment. The datathatwas presented is only interms weight percentages and only provides evidence that there will be sodium and potassium downstream ofthe electrostatic precipitator. While these compounds may existin a LDSCR environment, no attemptwas made by Minnkotato quantify howthese weightpercentage would translate to loading to a LDSCR andhow that would affect catalystlife. Therefore, using this datato show thatthe presence ofsodium and potassium compounds downstream ofthe electrostatic precipitatorwould preclude the successful operation ofa LDSCR is completely speculative and highly questionable. The NDDH BACT determination uses this**d~ta** 

### in conjunction with an emission factor comparisonpresented inthe NDDH analysis to reach a similarconclusion. Withoutknowing whatthe total amount ofloading is downstream ofthe electrostatic precipitator and how these weightpercentages relate to LDSCR loading and catalystlife, however, the conclusions inthe NDDH BACT determination are pure speculation and highly questionable. The NDDH BACT determination also uses this datato supportthatconclusionthatthese catalyst poisons will enter a TESCR, eventhoughthe sampling was done withoutwet scrubbing. Using this datain anyway to supportthe conclusionthat aTESCRcould notbe successfully operated is completely without merit. As explained inthe expert opinionreportby Mr. Hartensteinprovided herein, soluble compounds would almost completely be removedby a wet scrubber and the flue gas temperatures after gas reheat for either a TESCRorLDSCR system would be higherthan those expected for condensation ofany trace sodium or potassium compounds remaining. Therefore, the MRYS Unit 1 sampling presented does not



### -3-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS 

### demonstrate, to any degree, that a TESCRor LDSCR could notbe successfully operated at MRYS.8 

### Minn-DakFarmer's Coop. Experience As explained in detail in Mr. Hartenstein's expert opinion report, using the experience atthe Minn-DakFarmer's Coop. facility to make the claimthat TESCR and LDSCR is technically infeasible at MRYS is unfounded. First, the pollution control atthe Minn-Dak facility is completely unlike that at MRYS. The Minn-Dakboilers are equipped with multiclones and a venturi scrubber. The lack ofsimilarity ofMRYS to other facilities that have successfully operated SCRhas been used extensively elsewhere in the NDDH BACT determination to supportthe claim ofSCRtechnical infeasibility, yet this fact seems to be unimportantto the NDDH in this instance. The NDDH BACT determination also makes no attempt to relate the particulate matter emissions experienced at Minn-Dak to atheoretical TESCR sodium loading rate and catalystlife at MRYS thatwould supportthe claimthat the· Minn-Dak situation is evidence that TESCR would notbe technically feasible at MRYS. This is likely because no such case couldbe made. Furthermore, as explained elsewhere herein and in Hans Hartenstein's expert opinionreport, stacktemperature conditions (and how those temperatures relate to the physical state ofcatalystpoison compounds) during a particulate matter stacktest (as would have beenthe case inthe Minn-Dak situation) andthe operation ofa TESCR after flue gas reheat are very different. Therefore, to use the NDDH's experience with the Minn-Dakfacility to supportthe conclusion that TESCR could notbe successfully operated at MRYS is completely speculative anq highly questionable. SCR System andCatalyst VendorResponses on TESCR The NDDH BACT determination fails to adequately address the vendorresponses provided by Minnkota in the evaluation ofTESCR or LDSCR. This is likely because the B&McD SCR system and catalyst vendor query appears to have been specifically directed at only getting responses related to a HDSCR application and with no attemptmade to get information aboutvendor opinions or guarantees relatedto TESCRor LDSCR.

. As detailed in Mr. Hartenstein's expert opinionreport, an additional query was made to the same vendors thatwere contacted by B&McD to getinformation ontechnical feasibility, the need for additionalresearch, and guarantees relatedto TESCR.

8 Although not referenced in the NDDH BACT determination, Minnkota also submitted some sampling information for Unit 2 thatmay have been taken downstream ofthe electrostatic precipitator and S02 scrubber (although the bypass was operating during the sampling). As explained in Mr. Hartenstein's expert opinion report, this data cannotbe considered relevant for any reasonablejudgmentconcerning the technical feasibility ofaTESCR. 

### -4-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS


### The responses received from SCR system suppliers (Alstom and BabcockPower) and catalyst vendors (Argillion, CERAM, and HaldorTopsoe) that have extensive experience with TESCR demonstrate that TESCR is available and applicable to MRYS withoutthe need to do additional pilottesting. This information is very important, because these experts have actual experience withthese installations. While much ofthis experience is outside ofthe United States, that should not influence the analysis oftechnical feasibility. Clearly, these companies will make TESCR available to Minnkota and believe the physical and chemical characteristics ofthe flue gas at MRYS in a TESCR environmentposes no significant differences thatwould preclude the successful operation at MRYS. 

### Conclusion on TESCRTechnical Feasibility Based onthe evidence outlined above, in addition to the substantial explanation provided inthe expert opinion report ofMr. Hartenstein, a leading expertin SCR installations atpowerplants, TESCR is atechnically feasible control option at MRYS and

.needs to be evaluated to at least step 4 ofthe Top-Down BACT analysis.



### Conclusion on LDSCRTechnical Feasibility Since no apparent attempt was made to query vendors related to LDSCR, this analysis remains incomplete. While both Minnkota and the NDDH have made technical arguments as to why LDSCRwould be technically infeasible at MRYS due to catalystplugging and deactivation, these arguments are based onpure speculation and improper comparisons with other situations that do not quantitatively provide any evidence that LDSCR could notbe successfully operated at MRYS. EPA believes LDSCR is very likely technically feasible. 

### II. .NDDH'S TECHNICAL FEASIBILITY ANALYSIS OF HIGH-DUST SCRIS INCORRECT AND BASED UPON FLAWED DATA. As more fully setforth below, the NDDH BACT determination's conclusionthat HDSCRis technically infeasible is not supported by the record and is based upon an incorrectinterpretation ofEPA's NSRManual. NDDH's BACT determinationprovides twelve reasons to support its decisionthat HDSCRis technically infeasible. These individual points are examined in detail in

### Mr. Hartenstein's expert opinion report and will notbe expoundedupon here in detail. HDSCR CatalystPlugging & 

### Deactivation

• The catalystplugging and deactivationproblems cited inthe NDDH's BACT determination are largely based uponthe Coyote Station pilottestconducted by EERC, which was fundamentally flawed and would not be indicative ofa full-scale operation. 

### -5-EPA Comments onNDDH Preliminary NOx BACTDetermination forMRYS



### • The NDDH BACT determination acknowledges the fundamental problems with Coyote Stationpilottest and states that itprovided little useful data. However, the pilottest is citedthroughoutthe HDSCRtechnical feasibility analysis as abasis for supporting the position that HDSCR is technically infeasible.9



### • The comparison ofdifferent coal-type emission factors in the NDDH BACT determination is used to supportthe conclusion thatthe differences in flue gas characteristics ofsodium and total primary alkali constituents (CaO, Na20, MgO, and K2 0) would "preclude the successful application ofexisting (presumably high-dust) SCRtechnology to the M.R. Young Station."lO This conclusion is complete speculation. While the NDDH BACT determination correctlypoints outthat a linear relationship does not existbetweenthe loading rates ofalkali constituents derived from emission factors and catalyst deactivation, theNDDH BACT determination uses this comparisonto draw the conclusionthatthe flue gas characteristics at MRYS would be sufficiently "different" than otherfuel types where SCRhas been successfully applied. Again, there is no clearbasis for this conclusion. The comparison shows cyclone units firing North Dakota lignite to emit about six times as much NaO and abouttwice as muchprimary alkali constituents as wall-fired or tangentially-fired plants burning Wyoming Powder River Basin (PRB) subbituminous coal. The NDDH BACT determination does not attemptto relate these ratios to expected catalystlife;

• Forthe current coal analyses, the ratios ofprimary alkali loading for CenterMine cyclone units compared to Texas Lignite cyclones, Texas Lignite pulverized units, and PRB subbituminous pulverized units are 

### 1.7,2.0, and 

### 23 respectively. There is a larger disparity between the same primary alkali constituents on units within other fuel andboilertypes that have successfully demonstrated SCRuse. For example, the· ratio ofprimary alkali constituent loading between pulverized coal units burning PRB subbituminous coal versus easternbituminous coal on a Ib/MMBtu basis would be 3.0. This difference is higherthanthe 2.3 ratio between a CenterMine cyclone unit and the same pulverized unitburning PRB. Therefore, pasedonthe methodology and

'.J 9 For example, on pages 49-50, the NDDH BACT determination states, "[t]he pilot scale SCRplugged after only 2 months and little useful data was obtained

.....Operation ofan SCR system for only 2 months between catalyst replacement is not considered successful operation ofSCRtechnology." Based on this discussion, the NDDH is strongly implying that a HDSCR at MRYS would need a catalystreplacement due to deactivation after only two months, although it is widely known that information relatedto catalystplugging on a pilot scale is not applicable to full-sca:Ie installations and no activation data was obtained onthe Coyote Station pilottest. The NDDH BACT determination also states the Coyote Station pilot testwas "ill-designed for a unit combusting North Dakota lignite" (see page 7), which makes the use ofthis 2-month prediction ofcatalystreplacementbased on pilot-scale plugging results even more baffling. 10 See NDDH BACT determination, page 51. 

### -6-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS


### rationale presented inthe NDDH BACT determination, HDSCRcould nothave been successfully appliedto pulverized coal units burning PRB subbituminous coal because there was three times as muchprimary alkali constituentloading inthe flue gas comparedto the easternbituminous coal plants, where SCRhad already been successfully operated.

• Despite the considerable and varied experiencethat exists worldwide with applying SCRon different source and fuel types, the NDDH BACT determination dismisses the notion thatHDSCR is technically feasible at MRYS as "speculation." However, theNDDH believes a mathematical comparison showing elevated amounts ofsodium and other alkali constituents in the flue gas with some unknown effect on catalystlife in a HDSCR location is "evidence" that HDSCR is technically infeasible at MRYS.

• The responses from two ofthe three catalystmanufacturers (CERAM and Haldor Topsoe) to the B&McD query related to HDSCR indicates that catalyst suppliers would be willing to guarantee HDSCRperformance ifthe temperature issue unique to the units atMRYS was resolvedby SCR system suppliers. The catalystvendors expressed concern aboutthe flue gas constituents ofNorthDakotalignite, but did not indicate there was a fatal flaw to operating HDSCRbased onthe fuel type. The issue ofsodiumpoisoning was specifically discussed byCERAM andwas not a cause of concernbased ontheir past experience with high sodium applications. Haldor Topsoe was also made aware ofthe sodium issue and was able to provide an industry-

.standard guarantee. The catalystsuppliers were able to estimatethe catalystlife ofa HDSCR application at MRYS based ontheir previous experience.

• It 

### is apparentthatthe catalyst suppliers that responded affirmatively to being able to provide performance guarantees on a HDSCR ifthe temperature variation issue was resolved (CERAM and HaldorTopsoe) were prompted by B&McD to issue statements thatpilottesting onNorth Dakotalignite would be requiredpriorto such guarantees. ll 

### As noted in

### Mr. Hartenstein's expert opinionreport, catalystvendors would always be in favor ofdoing HDSCR pilottesting for a new fuel type, as it minimizes theirrisks at little or no costto themselves.

• CERAM responded to B&McD's follow-up by stating that "we agree that there is good cause for further testing on a lignite fired unitto further mitigate the risks and optimize design." This statementis clearly a recommendation that acknowledges testing would enhance the applicability oftheir catalystin a HDSCR applicationto North Dakotalignite, not arequirement in orderto develop its availability. In its May 11,2007 response to the B&McD query, CERAM outlined detailed design ofthe
11 See April 28, 2008 emails from Robert Blakley (B&McD) to Noel Rasha (CERAM) and Flemming Hansen (HaldorTopsoe). 

### -7-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS 

### catalyst and guaranteed a catalystlife of 16,000 hours. Contrary to statements inthe NDDH BACT determination thata HDSCR could not be designed at MRYS due to uncertainties in deactivationrates ofthe catalyst, a very experienced and reputable catalystvendor has expressed confidence that it could do so (ifthe temperature variation issue is resolved) and provided such information.

• HaldorTopsoe respondedto B&McD's follow-up by stating, "[w]e suggestthatthe next step is a largerpilot scale experimentwith in the order of2x2m ofcatalyst installed. We would like to participate in such an experiment. This would allow better catalystcleaning and give a better determination ofthe catalyst degradation overtime. Based on our currentinformation, we expect 60% deactivation overthe first 10,000 operating hours. We cannot provide a 'make good' guarantee',.butare willing to warrantthe catalystperformance up to the contract value." These statements are clearly a recommendationthat acknowledge testing would enhance the applicability oftheir catalyst in a HDSCR applicationto North Dakotalignite, not a requirement in orderto develop its availability. In fact, contrary to statements inthe NDDH BACT determination that a HDSCR could not be designed at MRYS due to uncertainties in deactivation rates ofthe catalyst, a very experienced and reputable catalyst vendor has expressed confidence that it could do so, provided the temperature variation issue is resolved. As explained in Mr. Hartenstein's expert opinion report, the guarantee up to the contract value is a standard industry guarantee. Thus, the statements by HaldorTopsoe do not supportthe notion that HDSCR would require pilottesting in orderfor commercial availability, as outlined·inthe NDDH BACT determination.

• The export opinionreport ofMr. Hartenstein clearly indicates that based on his extensive knowledge and experience with SCR applications under widely different flue gas conditions and discussions he had with catalystvendors and SCR system suppliers, catalyst andplugging and deactivation would not be a fatal flaw to installing HDSCR at MRYS.

• As will be explained in more detail in alater section, the docket informationforthe TXU Oak Grove New SourceReviewpermit (aproposed projectthat will include HDSCR and burn 100% Texas lignite) provides further evidencethat, despite the challenges that existin applying HDSCRto a new fuel type, the utility industry believes that SCRis technically feasible and any questions aboutthe its application are a matter ofcost. This is evident not only in the permit docket, but also in a letter from the Electric Power Research Institute thatwas originally sentto the NDDH in EPA's January 8, 2007 letter. In addition, the Texas Commission on Environmental Quality determinedthat the uncertainties involved with firing a new fuel type andthe accelerated HDSCR catalystplugging and deactivation that was expected from


### -8-/ EPA Comments on NDDH Preliminary NOx BACTDetermination forMRYS 

### exclusively firing Texas lignite was not a reason to find that SCRwouldbe technically infeasible. While the properties ofNorth Dakotaand Texas lignite might notbe the same, the same basic principle applies thatthe accelerated catalyst replacement requirements are a matter ofeconomics and nottechnical feasibility. Based on the information and observations above, EPA concludes thatthe successful operation and technical feasibility ofHDSCR at MRYS would notbe precluded by the catalystplugging and deactivation issues related to the cyclone-firing North Dakota lignite described by Minnkota and in the NDDH BACT determination. Catalyst vendors believe the challenges involved would be manageable and they would be able to design a suitable catalystwith a performance guarantee. While the vendors wouldpreferto conduct some testing to mitigate risks, optimizethe design, and betterpredictcatalystlife, these same vendors also appear willing to make the catalyst commercially available. Therefore, HDSCR should notbe eliminated as being technically infeasible onthe basis ofcatalystplugging and deactivation. 

### MRYS Temperature Variation Issue Relatedto HDSCR

• The SCR system supplierresponses indicate thatthe temperature variation issue would likely be very challenging for a HDSCR installation atMRYS (and more unique than the potential catalystplugging and deactivation issues for cyclone-firing ofNorth Dakota lignite). Although the B&McD query was clearly directed toward a response only on HDSCR, SCR system suppliers (Alstom and BackbockPower) suggested looking at the possibility ofTESCR as a way ofavoiding both the concerns with temperature variations and fuel characteristics.

• The other SCR system supplier (Babcock & Wilcox, which does not have extensive TESCR experience) certainly did not dismiss the possibility ofbeing able to overcome the challenges presented at MRYS for SCR installation and welcomed working withMinnkotato explore "creative solutions."

• EPA received information in response to a CleanAirAct Section 114 request pertaining to the vendor query conducted by B&McD. 12 

### This information is included herein. Babcock & Wilcox (B&W), who was the original manufacturer ofthe boilers at MRYS, indicates thatmodifications to the boiler likely couldbe made that would address the temperature problems, orthat out ofboiler modifications/changes (e.g. auxiliary fuel drying) would be necessary. In either case, the temperature issue appears to a resolvable technical problem, albeit at a likely high cost.

12 See July 18,2007 e-mail from Steve Moormann (Babcock & Wilcox) to Robert Blakely (Bums & McDonnell). 

### -9-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS



### EPA believes thatthe technical issue withthe temperature variation inthe backpass end ofthe boilers at MRYS where a HDSCRwould be located presents a,significant challenge. However, itappears that the technical challenges withthetemperature variation can be resolved. Furthermore, the issue ofbackpass boilertemperature variation completely goes away inthe case ofTESCR and LDSCR. Therefore, no matterwhatthe implications are ofresolving the temperature variation issue, there are otheroptions for installing SCR technology thatwould avoid this problem altogether. 

### EPA's Conclusion on HDSCR In summary, EPAbelieves the NDDH BACT analysis incorrectly eliminates HDSCR as technically infeasible at MRYS because pilottesting would be required on CenterMine lignite fuel before application at MRYS. The uniqueness ofthe fuel at MRYS (CenterMine lignite) does not appear to pose technical problems that catalyst vendors do not believe can be managed in orderto provide areasonable guarantee. The soluble sodium deactivation issue cited inthe NDDH BACT determination as a fatal flaw to installing HDSCR is not supported by any useful orrelevant data and is speculative. Furthermore, the opinions of catalyst suppliers and leading SCRexpertMr. Hartenstein indicate that catalystpoisoning by sodiumis only an issue during periods when, the catalystis allowedto cool well below its normal operating temperature. This wouldbe an infrequent occurrence and canbe managed by isolating the catalyst during shut-downs. Additionally, catalystregeneration is a viable option (that is currently used inpractice) for restoring catalyst life by either in-situ, on-site, or off-site water washing. 13 

### The temperature variationproblem appears to be a more significant challenge for the successful operation ofHDSCR (butnot TESCR or LDSCR), butthe necessary modifications to resolve this problem would be a matter ofcost. 

### III.' THE NDDH BACT DETERMINATION INCORRECTLY APPLIES THE CONCEPT OF PILOT TESTING IN EPA'S NsRMANUAL TO CONCLUDE THAT SCRIS NOT TECHNICALLYFEASIBLE. NDDH has misinterpreted EPA'sNSR Manual to support a finding oftechnical infeasibility ofSCR at MRYS because ithas been suggested pilottesting and/or engineering researchwould be required. EPA has previously clarified for Minnkota andthe NDDH that this reference in**E~A's** 

### NSRManual is only relevantto whether a control option was.

13 On page 46, the NDDH BACT detennination states thatthere are "no known engineering solutions to
....restore the catalytic reactions by removing particles from catalystpores." This is simply nottrue and it appears thatthe NDDH did not investigate this possibility in any depth. As one example ofactual regeneration experience, EPA is enclosing a 2007 NOx Round Table & Expo Presentation by Reinhold Environmental Ltd (February 5-6, 2007 in Cincinnati, OH) that details in-situ and on-site catalyst washing experience atthe Avedore Station in Denmark. 

### -10-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS


### "available." There is little question that SCR is "available" for installation at MRYS and, in fact, the MinnkotaBACT analysis already conceded that SCR is "available.,,14 The NDDH BACT determinationrelies uponthe lack ofdemonstrated application of SCR technology and mitigating tools used to manage ash deposition and catalyst deactivation (such as screens, baffles, soot-blowing, rejuvenation, etc.) on a cyclone boilerfiring North Dakota lignite to conclude that it is necessary for the source to do additional pilottesting and engineering studies. According to NDDH's interpretation ofEPA's NSRManual, this additional step precludes the technology from being considered technically feasible. The NDDH BACT determination states that, "[t]he fundamental question for this BACT determination is whether SCR is an available technology for North Dakota lignitefired cyclone boilers such as MinnkotaUnits 1 

### and 2.,,15 The concept ofavailability ofa control technology is introduced in the NDDH BACT determination by quoting EPA's NSR Manual, which states, "[a] control technique is considered available, within the context presented above, ifit has reached the licensing and commercial state ofdevelopment. A source would not be required to experience extendedtime delays orresource penalties to allow research to be conducted on a newtechnique. Neither is it expected that an applicant would be required experience extendedtrials to learn how to apply a technology on a totally new and dissimilar source type. Consequently, technologies in the pilot scale testing stages ofdevelopment would not be considered available for BACT review.,,!6 The NDDH BACT determination concludes, "SCRhas notreached this stage for North Dakota lignite-fired cyclone boilers, and because ofthe difference in the gas stream!?, the Departmentconcludes that Minnkotaneed not experience extendedtrials to learnhowto apply the technology on such a dissimilar source type.,,18 Withthis statement, NDDH has erroneously combined two steps which are described in EPA's NSR Manual as separate steps for determining technical feasibility ofa control option,

14 See EPA's October4, 2007 letterto NDDH and Minnkota, page 31 and Minnkota BACT analysis, page AI-32, where B&McD states, "SCRtechnology is an available technology which has been installed on numerous powerplant facilities around the world and there are a large numberofmanufacturers thatmarketthe technology. The question is whether SCRtechnology is "applicable" fOfa unit firing North Dakota lignite." In its November 13, 2007, letter, Minnkota appears to have reversed course on the issue ofSCR availability, and attempts to focus on the dissimilar aspects ofMRYS to otherfacilities thathave installed SCR. Notwithstanding the statements in this letter, however, there is no disputing that the Minnkota BACT analysis clearly stated that SCR is available and thatthe only question is whether it is applicable. 15 See NDDH BACT Determination, page 5. 16 See EPA's NSR Manual, page 8018. 17 The concept ofevaluating differences inthe gas stream between the source under review and other sources where a control option has been applied is introducedin EPA's NSR Manual during the discussion ofwhether an available control option is also applicable. 18 See NDDH BACT Determination, page 6. 

### -11-EPA Comments on NDDH Preliminary NOx BACT Determination forMRYS 

### namely, availability and applicability, A plainreading ofEPA's NSR Manual shows that EPA saw the technical feasibility determination as two separate steps. First, the reviewing authority should determine whether a control option is available. As stated in the EPA NSR Manual, ifa

### new control option is only in the early developmental stage, it is riot considered (commercially) available. Therefore, underthe Top-Down BACT analysis, the control option is eliminated from consideration as being technically infeasible, without any analysis on whetherthe control option is applicable to the source under review and does not require the same degree oftechnical analysis andjudgmentonthe part ofthe reviewing authority. EPA's NSR Manual specifically mentions pilottesting as a component ofdetermining availability, which is defined as the "process commonly used for bringing a control technology conceptto reality as a commercial product.

• conceptstage;

• research and patenting;

• bench scale or laboratory testing;



### • pilotscale testing; (emphasis added)

• licensing and commercial demonstration; and

• commercial sales." 19 For determining whether a control option is available, EPA's NSR Manual does not describe the comparison ofgas stream characteristics between the source underreview and other sources. Commercial availability ofSCRis a plain fact, evidenced by the SCR system supplier and catalyst vendorresponses garnered by B&McD and supplementedby EPA herein, the extensive applications ofSCRto coal-firedpowerplants and other industrial sources worldwide for decades, and eve.n as stated inthe MinnkotaBACT analysis. 20 

### The second step ofthe technical.feasibility analysis is to determine whether an available control option is also applicable to the source under review. As noted correctly in the NDDH BACT determination, the EPA's NSR Manual "provides that technicaljudgment ofthe review authority must be exercised in detetmining whether a control alternative is applicable to the sourcetype under consideration,,21 (emphasis added) and cites aportion EPA's NSRManual regarding applicability, which states, "acommercially available control option will be presumedto be applicable ifithas been or is soon to be deployed (e.g. is
19 See EPA's NSRManual, page B.17. 20 EPA also strongly disagrees withthe assertion in the NDDH BACT determination that a control option can be eliminated underthe Top-Down BACTprocess ifany "engineering study" is required. This very vague and broad term could be appliedto any phase ofdesigninga piece ofpollution equipment ortechnique. Presumably, every major piece ofpollution control equipment (Le. scrubber, SCR, baghouse, Electrostatic Precipitator, etc.) appliedto a utility boilerhas entailed engineering study. EPA categorically dismisses use ofthis term in NDDH's BACT determination andbelieves thatthis extremely narrow view ofwhat is required in the Top-Down BACT process is particularly problematic. 21 See NDDH BACT Determination, page 5 and EPA's NSR Manual page 8.18. 

### -12-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS 

### specified in apermit) onthe same or similar source type. Absenta showing ofthis type, technical feasibility would be based on examination ofthe physical andchemical characteristics ofthe pollutant-bearing gas stream and comparison ofthe gas stream characteristics ofthe source types to whichthe technology has been applied previously.,,22 (Emphasis added.) Hence, a comparison ofgas stream characteristics would onlybe required once ithas already been established thatthe control option is available. Furthermore, the question ofwhetherpilottesting and conducting additional research is necessaryno longer applies to the analysis, since itis only relevantfor a determination ofavailability, which would have already been confirmed. Contraryto EPA's NSRManual, the NDDH BACT determination makes a determination ofavailability based, inpart, on the comparison ofgas stream characteristics. The NDDH BACT determination states, "all responses (to the B&McD vendor query) indicated the following: l}The need for additional testing to either determine ifthere were any fatal flaws orto obtain data for the design ofa potentially successful SCR system.',23 Clearly, this is notthe type ofpilottesting thatis referenced in the·EPA NSR Manual for developing anew control technology from concept stage to the commercial state of development. This type oftesting would instead provide more certaintyto designers and likely result in amore optimum SCR systemdesign at MRYS, as it wouldto any application ofSCRto anew,plant. In other words, this type oftesting would be usedto enhancethe applicability ofSCRat MRYS. The responses from SCR system suppliers and catalyst vendors are speaking to the advantages ofdoing additional testing onNorth Dakota lignite to enhance the applicability of(HD)SCR at MRYS, not on whetherSCR is acommercially available control technology. Forexample, whenprompted by B&McD onthe prospectof doing pilottesting, CERAM stated, "we would agree thatthere is good cause for further testing on a lignite fired unit tofurthermitigate the risks andoptimize design.,,24 

### (Emphasis added.)

. Since SCRhas been so widely applied to coal-firedboilers and otherindustrial sources, commercial availability ofSCR should be determinedprimarily based on whetherthe SCR system suppliers and catalyst suppliers ·are willing to commercially provide and install the technology onthe source in question, notbased on whetherthe reviewing authority believes additional testing wouldprovide more certainty and lead to a betterdesigned SCR. It is clear from the record thatvendors are willing to do so. Many ofthe vendors responses from the B&McD query clearly indicate thatthey believe SCR can work at MRYS2 and do not
22 See EPA's NSRManual, page 8.18. 23 See NDDH BACTDetermination, pages 39-40. 24 See May 6, 2008 email from Ceram Environmental, Inc. to B&McD. 25 See May 30, 2007 and May 5, 2008 letters from Alstom Powerto B&McD; see May 11,2007 and May 6, 2008 emails from Babcock PowerEnvironmental, Inc. to B&McD; see May 11,2007 and May 6, 2008 emails from Ceram Environmental, Inc. to B&McD; see May 10,2007 and May 5, 2008 emaiisfromHaldorTopsoe.Inc.to B&McD. Note thatthese responses have been greatly supplementedby the vendorresponses related to TESCR 

### -13-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS 

### require that pilottesting be conducted upfrontto make the technology commercially available.

. Lastly, the NDDH BACT Determination for LDSCR and TESCR at MRYS also concludes, "catalystdeactivation ofa low-dust ortail gas SCR due to alkali compounds is an issue thatwill require extensive research, design and pilottesting to determine whetherthe technology can be successfully appliedto units fired on North Dakotalignite. Therefore, these technologies are not considered applicable and nottechnically feasible at this time.,,26 Again; this rationale is a misinterpretation ofthe EPANSR Manual. The question of whether LDSCR and TESCR are in the pilottesting stage ofdevelopment is only relevant in terms ofwhether it is an available control option. Both LDSCR and TESCR are not only available control options, butwould also be applicable to MYRS. In fact, the responses from the supplemental SCR system catalyst vendor query conducted by Mr. Hartenstein, and provided inthe Enclosure herein, clearly indicates that vendors wouldprovide a TESCR at MRYS with a guarantee and do not support doing any additional pilottesting. 

### IV. THE NDDH BACT DETERMINATION FRUSTRATESTHE TECHNOLOGYFORCING FUNCTION OF THE BACT PROCESS THAT WAS INTENDED BY CONGRESS. The NDDH BACT determination is not only atodds with EPA's NSR Manual, but it also frustrates the technology-forcing function ofthe BACT process. As described above, the NDDH BACT determination repeatedly notes a lack ofactual experience with SCRon North Dakota lignite and cyclone boilers as aprimary basis for concluding that "experimentation" and/or "extensive, and correspondingly expensive, engineering studies" would be necessary to determine ifUncertainties could be overcome. Congress developedthe case-by-case BACTprocess so thatthe besttechnology becomes as widespread as possible. The NDDH BACT determinationtakes the positionthat a control option is technically infeasible because no otherpowerplantwiththe exact same design and fuel source has applied the control option. Underthis presumption, the besttechnology would not become widely used, unless some independent "proof' ofitworking onthe exacttype ofsource and flue gas characteristics underreview was provided. This application ofthe BACTprocess is contrary to the technology-forcing function ofthe BACTprocess that congress intended when enacting Clean Air Act.

gathered by Mr. Hartenstein.

. 26 See NDDH BACT Determination, page 57. 

### -14-EPA Comments on NDDH Preliminary NOx BACTDetermination for MRYS 

# v. OTHER COMMENTS ON THE NDDH BACT DETERMINATION 1. 

### Page 4 ofNDDH BACT Determination: "Information from Sargent and Lundy indicates that not enough information is available to determine whether SCR technology canbe successfully adaptedto units burning North Dakota lignite." EPA Response: This is not what Sargent & Lundy actually said inthe May 

### 2007 presentationto NDDH and EPA. In Sargent and Lundy's Conclusion Summary, they state, "[slome importantunanswered questions pose significantrisks for an SCR design engineer: An unknown catalyst deactivation rate will prevent:

• optimum selection ofa catalyst design

• selection ofan appropriate reactor size This could burden the operator with a long term costly maintenance requirements (sic) and unscheduled outages" Sargent & Lundy states thatpremature catalystfailure will require more frequent catalystreplacement, ammonia slip and subsequent airheaterpluggage, and higher auxiliary powerrequirements. These conclusions suggestthat Sargent & Lundy's opinion is thatthe lack ofdata specific to NorthDakotalignite on SCR operation wouldresult in a less than optimal design and as a result increased capital and operating costs. While this opinion indicates that applying SCRto North Dakota lignite withoutobtaining further datamightnotbe the best engineering approach, Sargent & Lundy did not opine that SCR could not be "successful" on units firing North Dakotalignite. 2. Page 70ftheNDDH BACT determination: "The advances made inthe last few years for controlling popcorn ash are not shownto·be applicable to a cyclone boilerburning North Dakotalignite. Extensive engineering analyses, and likely pilot scale testing, will be necessary to determine ifthese advances canbe applied atM.R. Young Station." EPA Response: This statement and conclusion is inconsistentwiththe discussions betweenNDDH, EPA, and Minnkota atthe May 

### 23,2007 meeting heldin Bismarck. During this meeting popcorn ash was discussed and EPA's consultant, Roger Christman, statedthathe believedthe popcorn ashproblemhad been dealt with successfully atmany otherfacilities and that itwould not pose a significantproblem at MRYS. Mr. Christman asked Minnkota and B&McD whetherthey agreed that the


### -15-EPA Comments on NDDfI Preliminary NOx BACTDeterminationfor MRYS


### effects ofpopcorn ash is solvable at MRYS and whether 

### it couldbe "taken offthe table" as a real issue inthe discussion ofHSSCRtechnical feasibility. Minnkota agreed that it was a solvable issue and certainly did not indicate thatpilottesting would be requiredto address the effects ofpopcorn ash at MRYS. In light ofthese discussions, it is unclearwhy NDDH still believes that this is atechnical barrier for the successful operation ofHDSCR at MRYS. 3. Pages 13-15 ofthe NDDH BACT determination: In identifying all control technologies under Step 1 ofthe Top-Down BACT analysis, the NDDH BACT determination lists, "Fuel Switching/Blending/Cleaning." In the Step 2 analysis for this control option, the NDDH BACT determination cites experience atthe Big Stone Power Plant in South Dakota with switching to PRB fuel as not loweringNOx 

### emissions and then references a Seventh CircuitAppeals Court decision regarding the Prairie State Generating Station PSD permitthat stated fuel switching is not required for mine mouth powerplants in the BACT analysis. Therefore, the NDDH BACT determination concludes that switching orblending fuels otherthan Center Mine lignite in orderto mitigate the effects ofthe fuel on other control options would not be required. EPA Response: While the NDDH BACT determination appears·to have looked at fuel switching and blending, 

### it ignores the possibility offuel cleaning in Step 2, although fuel cleaning was correctly listed under Step 1. Many ofthe technical problems described intheNDDH BACT determination for installation ofother control options, such as SCR, are due to downstream conditions causedby the poor quality ofthe CenterMine lignite fuel (i.e. high ash, high sodhun, high moisture, low heating content, the needto do fuel predrying in the cyclone boiler, etc.). Therefore, it appears thatNDDH should explorepotential fuel cleaning possibilities to address these effects. While EPA does not agree that fuel cleaning would be required in order for SCRto be considered technically feasible, the conclusions ofthe NDDH BACT determination are further flawed and incomplete without such an analysis. 4. Page 29 ofthe NDDH BACT determination: "Consumers Energy indicated they purchase coal from several western mines as well as easternmines. They also· indicated that none ofthe coal obtained from the Spring Creek Mine is fed to a unit equipped with an SCR system. Based onthis information the Departmentis not aware ofany powerplantthat is equippedwith an SCR system and bums Spring CreekMine coal." EPA Response: There is areference to a May 13, 2008 email froin Bradely Plummer ofConsumers Energy to Tom Bachman ofNDDH. This email was not made part of the administrative record, but appears to beinformation thatthe NDDHrelied upon in


### -16-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS 

### making its BACT determination. This email shouldbe made publically available and part ofthe administrative record for this BACT determination.

. 5. EPA would like to addthe documents identified in Sections VI through VIII, below, to the administrative record for the NDDH to consider in its Final BACT determination. 

### VI. DOCKET INFORMATION FORTHE TXU OAKGROVE NSR PERMITIS EVIDENCE THAT THE UTILITY INDUSTRY & 

### OTHER STATE AGENCIES BELIEVETHAT SCRIS TECHNICALLY FEASIBLE & 

### CAN BE APPLIED TO NEW FUEL TYPES & BOILERTYPES. On July 27,2005, Oak Grove Management Company, LLC (Oak Grove) appliedto the Texas Commission on Environmental Quality (TCEQ) for a Prevention ofSignificant Deterioration (PSD) permitto construct a new 1,600 MW (net) pulverized coal powerplant consisting oftwo 860 MW (gross) units. The proposed facility wouldbe fired on 100% Texas lignite. On February 21, 2006, the TCEQ Executive Director issued apreliminary decision and draft permitthatrequired HDSCR and a limit of0.08 lb/MMBtu as BACT for NOx. 

### At Oak Grove's request, the application and determination was referred to the State Office ofAdministrative Hearings (SOAH) for hearing on whether it complied with all applicable statutory and regulatory requirements. OnAugust 23, 2006, the SOAR Administrative Law Judges (ALJs) issued aProposal for Decision (PFD) with a finding that Oak Grove failed "prove by a preponderance ofthe evidencethatits BACT proposal to use SCRwithlignite-firedboilers can reasonably be expectedto achieve a 0.08lb1MMBtuNOx emission rate.',27 Essentially, the ALJs found that since HDSCRhas notbeenpreviouslyproven inpractice on a plantburning 100% Texas lignite, there were uncertainties withthe application of, "arelatively newtechnology thathas neverbeen used in the United States on a commercial scale with a lignite-fired electric power plant.',28 While Oak Grove tookthe positionthatthere were uncertainties and challenges with the designofan SCRreactor for lignite coal firing, the company argued that SCRis technically feasible and that, "the PFD failed to make the distinction between 'technical practicability' and 'economic reasonableness'.',29 Oak Grove takes the positionthat, "[t]o the extentthatthere is any issue or question regarding the use SCR (sic) at the proposed facility, it is a question ofcost.',30 Oak Grove's reason for pointing outthe uncertainties with

27 See AU's Proposal for Decision and Order, August23,2006, page 24. 28 See AU's Proposal for Decision and Order, August 23,2006, page 24. 29 See Applicant's Exception to the Proposal for Decision, September 12,2006 page 10. 30 See Applicant's Exception to the Proposal for Decision, September 12,2006, page 10. 

### -17-· EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS 

### applying SCRto a fuel type thathas neverbeen demonstrated in practice was an attemptto have the NOx 

### limitraised in the final permit, notto show that SCR should be considered technically infeasible. Additionally, Babcock Power Environmental, as the Air Quality Control System supplierfor Oak Grove, sent a letterto the TCEQ's Executive Director (August 

### 30,2006) outlining why itbelieves the ALl's PFD is incorrect and SCR is technically feasible for the Oak Grove plant. Interestingly, BabcockPower cites the EERC Coyote Stationpilottesting results and dismisses those problems based on moisture problems introduced by the sootblowers that caused much ofthe plugging during thattest. The TCED permitengineer for the Oak Grove permit, Randy Hamilton; also believed that HDSCR should notonly be considered technically feasible, but Mr. Hamilton also recommended a lowerNOx

### limit of

### 0.07 IblMMBtu to the TCEQ Environmental Director. Althoughthe ALJs appearto have misconstrued a statementmade by Mr. Hamilton in his written deposition to SOAH, where Mr. Hamilton describes the hypothetical best and worst case possibilities ofSCR ash deposition onthe Oak Grove units,31 Mr. Hamilton confirmed with EPA that it was never his professional opinion that the worst case scenario he described was a real possibility, but only a rhetorical examination oftwo logicallypossible outcomes.32 Ultimately, the TCEQ's Final Order (June 

### 21,2007) rejected the arguments over technical infeasibility ofSCR at Oak Grove, overturned the ALJ'sPFD, and grantedthe PSD permitto Oak Grove with aNOx 

### BACT determination ofSCR and a limit of

### 0.08 IbIMMBtu. In short, the Commission found thatthe ALJs "placed too much emphasis onthe absence of previous applications ofthe proposed technologies with regard to Texas lignite.,,33 Thepositions taken by the TCEQ (technical staff, Executive Director, and Final Order), Oak Grove, and BabcockPower largely coincide-with and supportEPA's position with regard to general technical feasibility ofSCR on different fuel types and whether questions of feasibility are a matter oftechnical feasibility or economic feasibility. EPA also generally agrees with these parties thatthe positiontaken by the ALls (and likewise by Minnkota and the NDDH inthe case ofMRYS), "will remove an essential element ofthe airemissions permitting process as contemplatedbyboth state and federal Clean AirActs

- the advancement ofairpollution control process.....Simply stated, the ALl's interpretation ofthe

31 See ALJ's Proposal for Decision and Order, August 23,2006, page 15, "[t]he uncertainty with regard to ash deposition is notmathematically convertible to a NOx emission limit adjustment. The ideal outcome wouldbe that plugging proyes to be no problem at all. Underthis scenario, NOx emissions couldbe as low as any coal-fIred boiler andthe BACT emission limit could have been lower. The worst outcome would be thatthe SCRplugs with flyash rapidly and completely and no engineering solution can be found. Under this scenario, SCRwould be technically infeasible, and BACT would have to be higher, based on the next most effective technology

..." 32 See April 16,2008 email from Randy Hamilton (TCEQ) to Hans Buenning (EPA Region 8). 33 See TCEQ Final Order, June 21,2007, page 45. 

### -18-EPA Comments on NDDH Preliminary NOx BACT Determination for MRYS


### technical practicability element ofthe BACT analysis would categorically preventthe first-

. time application ofnew control technologies inTexas.,,34 The same couldbe said ofthe state

ofNorth Dakotaunderthe positions taken inthe NDDH BACT determination. EPAis submitting theTCEQ/SOAH Docketinformation for the Oak Grove permit proceeding to be entered inthe administrative record and considered inNDDH's Final BACT determination (see Enclosure 3). 

### While EPA understands thatthere are differences between Texas and North Dakota lignites, as well as the boiler configurations at Oak Grove and MRYS that make the technical application ofSCRdifferent, the principles illustrated in the Oak Grove permitproceeding related to the BACT process largely parallel those inthe MinnkotaNOx BACT determination. EPA is also submitting additional information relative to the Oak Grove permitproceeding that is not contained in the docket (also part of Enclosure 3). 

### The docket can be accessed electronically at:
. http://www7.tceq.state.tx.us/uploads/eagendas/Agendas/2007/6-13

-2007/Oak%20Grove.pdf 

### VII. B&McD 114 RESPONSE DOCUMENTS On June 20, 2008, EPA issued a CleanAirAct, Section 114 request for informationto B&McD asking for informationrelatedto the SCR system and catalyst vendor query thatwas conducted by B&McD onbehalfofMinnkota. EPA received B&McD's response onJuly 3, 

### 2008. EPA is submitting portions ofthe response herein as part ofEnclosure 3 

### for the state to include in the administrative record and consider inNDDH's Final BACT determination. To summarize some significantfindings, the B&McD response indicates:

• Early draftversions ofthe vendor query document prepared by B&McD asked for vendor opinions ofthe temperature variation issue for HDSCRatMRYS andpossible boiler modifications that could address thisproblem. At Minnkota's direction, this request was removed from the final query document.

• Based on B&McD's call notes following up with the vendors that gave more optimistic responses in early 2007 (those that were less optimistic were deemed by Minnkota as not needing follow-up), it is clearthat catalystvendors were not swayed by**~he** 

### arguments set forth by B&McD and EERC relatedto the potential severity ofsodium catalystpoisoning. Also, SCRsystem suppliers told B&McD thatthey believe tail-gas SCR would resolve the problems being advancedby B&McDandEERC relatedto lignite fuel firing. Why B&McD did notpursue the tail-gas option with vendors after ithad been suggested is unclear.

34 See Applicant's Exceptionto the Proposal for Decision, September 12, 2006, page 8. 

### -19-EPA Comments on NDDH Preliminary NOx BACTDetermination for MRYS



### • Intwo separate documents (comments on a draft response to EPA comments dated February 6, 2007 and an email correspondence dated May 10,2007),. Robert Johnson (who was working as a consultant, but itis believed previously worked for Argillion and then B&McD) opined on many ofthe technical issues for an SCR at MRYS. The positions taken by Mr. Johnson largely support positions taken by EPA, namely that there is no useful underlying datathat supports the claims ofEERC regarding the severity ofsodium catalyst poisoning (in HDSCR, LDSCR, orTESCR), the Coyote Stationpilottesting "was a flawed test andthe results should notbe usedto draw any conclusions otherthan that a full scale system design needs to be done very carefully", sodium is not much ofa concern as a catalystpoison at SCR operating temperatures, and thatTESCR is a likely candidate for MRYS.



### • It appears Minnkotahas conducted a cost analysis ofSCRat MRYS using different expected catalyst life spans of 12,000 and 24,000 hours. This information has not been made publically available to EPA's knowledge. 

### VIII.DOCKET INFORMATIONFORTHE CLEANAIRINTERSTATERULE (CAIR), BESTAVAILABLE RETROFIT TECHNOLOGY (BART) GUIDELINES, AND NEW SOURCE PERFORMANCE STANDARDS jNsPS) STATES THAT EPA DETERMINED THAT SCRIS TECHNICALLY FEASIBLE FORLIGNITE FIRED UTILITY BOILERS. In a January 8, 2007 letter (sent via fax), EPA provided the NDDH with docket information and references relatedto various rulemakings (CAIR, BART Guidelines, NSPS), where EPA determined SCRto be feasible at lignite-fired utility boilers. This information does not appearto be completely inthe administrative record for the NDDH BACT determination, so EPA is providing informationrelatedto these rulemakings herein as part of Enclosure 3 for the NDDH to include inthe administrative record and consider inNDDH's Final BACT determination. As mentioned inthe January 8, 2007 letter, through these three rulemakings, EPA determined SCRto be technically feasible and rejected commenter's concerns that SCR wouldnot be technically feasible for lignite units, including those fired on North Dakotalignite. EPAreiterates thatthe position nowbeing taken inthe NDDH BACT determination is contrary to that establishedby EPA inthese three national rulemakings.

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## ENCLOSURE 3 ADDITIONAL DOCUMENTATION FOR ADMINISTRATIVE RECORD