# MONTANA-DAKOTA UTILITIES

### CO. ADMs;onofMDU RSSOUTC6SGroup, Inc.
400North FourthStreet Bismarck, ND58501 (701)222·7900

March 17, 2009

U.S. Environmental Protection Agency 1595 Wynkoop Street Denver, Colorado 80202-1129 Attention: Laurel Dygowski, 8P-AR

Re: Montana Dakota Utilities Co. Response to Reasonable Progress Request for Inforn1ation Pursuant to Section 114(a) ofthe Clean Air Act

- Lewis & Clark Station, 35023 Highway 23, South, Sidney, Richland County, Montana

Dear Ms. Dygowski:

Attached are Montana Dakota Utilities Co.'s (Montana-Dakota's) responses to the abovereferenced Request for Inforn1ation, dated January 29, 2009, received on February 2, 2009. The Request seeks information necessary to allow EPA to establish Reasonable Progress Goals (RPGs) as provided in Section 51.308(d)(1) ofthe Regional Haze Rules promulgated by EPA on July 1, 1999 or, alternatively, to allow the State of Montana to establish the goals should it choose to resume development ofits Regional Haze SIP at a future date. The Regional Haze Rules specify that RPGs are interim goals that represent incremental visibility improvement over time toward achieving the goal ofnatural background conditions by 2064. The goals are to be developed in consultation with other affected states and Federal Land Managers and are intended to improve visibility on the haziest days and to ensure no degradation in visibility on the clearest days overthe period ofeach implementationplan for each Class I area in Montana.

To determine what constitutes reasonable progress EPA will consider the following four factors: (1) the cost ofcompliance; (2) the time necessary for compliance; (3) the energy and non-air quality environmental impacts of compliance; and (4) the remaining useful life of existing
sources that contribute to visibility impairment. CAA § 169A(g)(1); 40 C.F.R. § 51.308(d)(1)(i)(A). You indicated during our March 5,2009, telephone conference call that EPA will supply the enclosed responses to a consulting firn1 retained by the agency to assist in developing the RPGs for Montana. By mid- to late Summer 2009 stakeholdcrs like MontanaDakota will be supplied a demonstration as to how the above factors either have been or will be considered in setting the RPGs for each Class I area in the State.

We believe that the demonstration EPA will supply should also, among other things: (a) establish applicable baseline and natural visibility conditions (and the basis for the same); (b) establish a Uniform Rate of Progress (URP) (and the basis for the same); (c) identify the
measures aimed at achieving the URP; and (d) identify the degree ofvisibility improvement in the forn1 ofemissions reductions that can be expected from existing or forecast local, State and Federal programs (including BART), which, alone, may suffice for demonstrating progress forLaurel Dygowski March 17, 2009 Page 2

RPG planning periods. In Montana, EPA's demonstration may be complicated by transboundary sources located in Canada that contribute to visibility issues. Therefore, in addition to the factors referenced at 40 C.F.R. 51.308(d)(1)(i)(A), and immediately above, it will be important for EPA's demonstration to consider trans-boundary sources over which it has no authority to control orregulate.

We have made every effort to provide complete and accurate responses to the Request for Information given the constraints posed bythe time provided to respond. Bye-mail to you dated March 6, 2009, I posed a number ofquestions regarding certain elements ofthe Request. I also asked for an extension oftime to March 31, 2009, to supply the response. Since I received no reply from you to the questions I posed or to the request for an extension oftime to respond, Montana-Dakota has made its best effort to respond accurately and completely. We reserve the right to supplement the responses in the future, as necessary, to further address any items we or you may subsequently determine require further explanation, supplementation, amendment or reVISIOn.

Should you have any questions regarding the attached responses, or this cover letter, please do nothesitate to call me.
Thankyou. Sincerely yours,

# ~~«::J 

# .. Abbie Krebsbach Environmental Manager

Enclosure

Statement ofCertification

I certify underpenalty oflaw that I havepersonally examined and amfamiliar with the information submitted in Attachment "A" to this letter and all related attachments and that, based on my inquiry of those individuals immediately responsible for obtaining such information, I believe thatthe information is true, accurate, andcomplete. I am aware that there

### ~~~~~~:~~~;/ penaltiesfor submilling

### i~ibilitY of fine of

Andrea Stom erg Vice President, Electric Supply 

# \1 \N\.cu

## c..~ ,2009

## Attachment A Montana Dakota Utilities Co.

- Lewis and Clark Station Requestfor Information Pursuantto Section 114 ofthe CAA March 17, 2009

PartI: General Facility Data

1. Name offacility: Lewis and Clark Station 2: Complete street address offacility (physical location):
a. Street Address: 35023 Hwy 23 South Southwest 1/4, Section 9, Township 22 North, Range 59 East b. City: Sidney
c. State: Montana d. Zip: 59270
e. County: Richland County 3: Facility contact a. Name (First Name, LastName): Abbie Krebsbach b. Title: Environmental Manager
c. Telephonenumber: (701) 222-7844 d. Fax number: (701) 222-7845
e. E-mail: abbie.krebsbach@mdu.com

PartII: BoilerEmission Unit Data (Please complete entire section for each boiler, additional copies may be necessary)

1: Emission Unit Name: EU1 (Tangential Coal/Natural Gas boiler)
a. Type ofBoi1er (e.g., spreader stoker, suspension-fired, fluidized bed): Dry Bottom, Tangential-Fired Coal/Natural Gas Boiler b. Make: Combustion Engineering
c. Model: Not specified in the original designplans and specifications d. Model Year: This was not apackage boiler. The model yearwas not specifiedin the origimi.l designplans and specifications. Construction of the boilerbegan in 1957 andwas completed in 1958.
e. Year Installed: Constructionbegan in 1957. Theplant commenced operation in 1958. f. Expected equipment life: Not specified in the original designplans and specifications. There are currentlyno plans or schedule for removing the facility from service. g. Unit Is Currently Operational (Checkone): DNO Ifyou answered YES above, continue on to h: Ifyou answered NO above,
answerthe following and then continue to nextunit: i. Date offinal operation: ii. Will this unitbe operational in the future (Check One)? DYES DNa h. Unit Capacity (MW gross/net): 52 MW gross/48 MW net. These values reflect the maximum sustainable capacity ofthe unit when firing on both coal andnatural gas. The dataprovided in this request canbe assumed tobe representative ofthe unit firing on coal alone, since the time periods when natural gas is used are very short. [Source: operational history]

2: BoilerUnit Outlet Information (Complete the following exhaust gas parameters for the indicated boiler. Ifthe boiler shares a common stackwith anotherboiler, please only provide exhaustinformation for the specifiedboiler).
a. Does this unit share an exhaust stackwith anotherunit? (Check One) DYES b. Maximum BoilerExhaust Volumetric Flowrate (acfm): 260,000 ACFM [Source: 1996 Title V App, Section 5]
c. Maximum BoilerExhaustTemperature (F): 155 0 F [Source: 1996 Title V App, Section 5] d. BoilerExhaustMoisture (%): 22% [Source: 2008 GE PM Test]
e. StackHeight (ft): 250 ft [Source: 1996 Title V App, Section 5] f. StackDiameter (ft): 8.75 ft at the outlet [Source: Drawing# L-22505 Sheet#S 14-10] g. Maximum Gross Heat Input (MMBtu/hr): 600 MMBtu/hr [Source: 1996 Title V App, Section 5] h. Annual Hours ofOperation:

Actual Annual Hours ofOperation Year Hours ofOperation 2005 6722 (scheduled outage) 2006 8139 2007 7669 2008 8156 [Source: Form 20]

J. DesignPercent Load (Capacity Factor): The design percent load or capacity factor are not specified inthe original design plans and specifications. The ability to operate continuously at 52 MW gross/48 MW net is limitedprimarilyby the quality ofthe coal. The actual annual net capacity factor is calculatedby dividing the annual net generation in MWhrs by the product of8760 hours and the maximum sustainable net capacity of48 MW. [Source: Form 20]

Actual Annual Net CapacityFactor Year Net CapacityFactor 2005 68% (scheduled outage) 2006 80% 2007 75% 2008 79%

J. 2001

- 2003 Maximum 24-hour Average Uncontrolled PM Emissions (lb/hr): There were no uncontrolled PM emissions for the time period specified. It is notpossible to operate the boilerunless the control system is in operation. Ifthe control system shuts down, the boileris automatically shut down. 2k. 2001

- 2003 Maximum 24-hourAverage Uncontrolled NOx Emissions (lb/hr): There were no uncontrolled NOx emissions for the time period specified. It is notpossible to operate theboiler unless the control system is in operation. The system is adjusted manually for optimum NOx emissions control. Ifthe control systemmalfunctions, butdoes not shut down, the boileris shut downmanually. 1. 2001

- 2003 Maximum 24-hourAverage Uncontrolled S02 Emissions (lb/hr): There were no uncontrolled S02 emissions for the time period specified. It is notpossible to operate the boilerunless the control system is in operation. Ifthe control system shuts down, the boiler is automatically shut down.

3: Existing Pollution Control Equipment (Complete the following for eachpiece of control equipment, make additional copies to provide information for all equipment).

a. PM Control Technology Information: Multi-Cyclone Dust Collector i. Type ofPM Control Technology: Multi-Cyclone Dust Collector [Source: 1996 Title VApp, Section 6] ii. Make/Model ofPM Control Technology: Western Precipitation Corporation! 9VGR-12 [Source: 1996 Title V App, Section 6] iii. YearInstalled: 1957 [Source: 1996 Title V App, Section 6] iv. Installed Cost ofControl Device ($/yr): Not itemized in original unit cost. Control equipment cost included in the cost ofthe boiler.
v. Direct Annual Cost ofControl Device ($/yr): (2008 Costs) -O&M: $79,547.80 (Approximate cost of$70,912.80 for ash hopperoperations and $8,635.00 for multi-cyclone dust collectorand ash hoppermaintenance. [Source: accounting] vi. Expected life ofequipment: Not specified in the original design plans and specifications. There are currently no plans or schedule for removing the existing control equipment from service. vii. Relevant sizing information (Please provide information sufficient to apply the EPA AirPollution Control CostManual- SixthEdition (EPA 452/B-02-001) Section 6

-- Particulate MatterControls Chapter2

- Wet Scrubbers for Particulate Matter): EPA 452/B-02-001 does not yet have a section that is applicable to multi-cyclone dust collectors. Section 6 chapter4, Inertial Impactors, is not available in the manual. Vane Type: VGR Tube Diameter: 9" Total Tubes: 406 [Source: Manufacturer's Installation and Operating Manual for Multiclone

- WesternPrecipitation Corporation] viii. Design control efficiency (%): 75%-80% ofPM [Source: 1996 Title V App, Section 6] ix. 2007 Average ControlledPM Emissions (lb/hr) and method of determination: The multi-cyclone dust collectoris notthe final PM control device. The wet scrubber, which is in continuous operation
3when the boileris firing, is located afterthe multi-cyclone dust collector. See Sectionix. oftheFloodedDisc Wet Scrubber.

FloodedDisc Wet Scrubber i. Type ofPM Control Technology: FloodedDisc Wet Scrubber [Source: 1996 Title V App, Section 6] ii. Make/Model ofPM Control Technology: Research

- Cottrell/model not specified [Source: 1996 Title V App, Section 6] iii. Year Installed: 1975 [Source: 1996 Title V App, Section 6] iv. Installed Cost ofControl Device ($/yr): $14,779,668 in 2008 dollars. The installed cost ofthe control device from 1975 and 1976 dollars was escalated to 2008 dollars using the Chemical Engineering Plant Cost Index. [Source: accounting]
v. Direct Annual Cost ofControl Device ($/yr): (2008 Costs) -O&M: $24,911.27 (Approximate cost ofoutage cleaning and I&C maintenance.) [Source: accounting] -Waste Disposal: $180,000 (Approximate annual cost of scrubberpond maintenance and ash disposal.) [Source: accounting] -Power: $123,134.18 (Total scrubberpower consumption plus halfthe ID fan powerconsumption for 2008 at $27.14 /MW.) [Source: accounting] vi. Expected life ofequipment: Not specifiedin the original design plans and specifications. There are currentlyno plans or schedule for removing the existing control equipment from service. vii. Relevant sizing information (Pleaseprovide information sufficient to apply the EPA AirPollution Control Cost Manual -.- Sixth Edition (EPA 452/B-02-001) Section 6 - Particulate MatterControls Chapter2

- Wet Scrubbers for ParticulateMatter): -Particle Size Distribution: Aerodynamic Diameter at Unit % less Density (Microns) than 0.6 4

1 5.6 2 17 3 28 4 37 7 52 10 57 14 62 [Source: Scrubber Operatmg Manual, Section 4] Loading: 1.12 gr/dscf

- 1.43 gr/dscf[Source: Scrubber Operating Manual, Section 4]

-Waste gas flow Rate: 168,930 acfm

- 313,730 acfm [Source: Scrubber Operating Manual, Section 4] Temperature: 3500 F - 4200 F [Source: Scrubber Operating Manual, Section 4] 4Humidity: 14.5%

- 17.8% [Source: ScrubberOperating Manual, Section 4] -Gas velocity and pressure drop Gas velocity: There is no value specified in the Scrubber Operating Manual. However, this value has been estimated to be approximately 126 feet per second based
on the normal disk operating height of14 inches and normal operating conditions. [Source: Scrubber Operating Manual, Section 4] Pressure Drop: 12 inches water column (IWC). The ScrubberOperating Manual specifies 13 IWC, but operational experience demonstrates 12 IWC is optimal. -Liquid-to-gas ratio: There is no value specified in the Scrubber Operating Manual. However, this ratio has been estimated to be approximately 12 gallons per 1,000 actual cubic feet based on normal operating conditions. [Source: Scrubber Operating Manual, Section 4] -Droplet size: There is no value specified in the Scrubber Operating Manual and the value is currently unknown. -Residence time: There is no value specified in the Scrubber Operating Manual. However, this value has been estimated to be approximately 7.0 seconds based on norn1al operating conditions. [Source: Scrubber Operating Manual, Section 4] viii. Design control efficiency (%): 98% ofPM [Source: 1996 Title V App, Section 6, and Scrubber Operating Manual, Section 3] ix. 2007 Average Controlled PM Emissions (lb/hr) and method of determination: 47.1 lb/hr [Source: Calculated from GE 2007 Particulate MatterEmissions Compliance Test Report]

b: NOx Control Technology Information: i. Type ofNOx Control Technology: Low NOx Firing System [ABB NOx Tuning Report] ii. Make/Model ofNOx Control Technology: ABB C-E Services, Inc.lLevel 1 Low NOx Firing System with Close-Coupled Overfire Air [ABB NOx Tuning Report] iii. YearInstalled: 1996 [ABB NOx Tuning Report] iv. Installed Cost ofControl Device ($/yr): $463,978 in 2008 dollars. The installed cost ofthe control device from 1996 dollars was escalated to 2008 dollars using the Chemical Engineering Plant Cost Index. [Source: accounting]
v. Direct Annual Cost ofControl Device ($/yr): -O&M: $52,861.10 (Approximate cost of$50,000per year for burnertip replacement and $2861.10 per year for burner cleaning and checks.) [Source: accounting] vi. Expected life ofequipment: Not specified in the original design plans and specifications. There are currently no plans or schedule for removing the existing control equipment from service.



### 5vii. Relevant sizing information (Please provide information sufficient to apply the EPA AirPollution Control CostManual- Sixth Edition (EPA 452/B-02-001) Section 4

- NOx Controls Section 4.2

- NOx Post-Control Chapter 1

- SelectiveNon-Catalytic Reduction and the EPA AirPollution Control Cost Manual

- Sixth Edition (EPA 452/B02-001) Section4

- NOx Controls Section4.2

- NOx Post-Control Chapter2

-- Selective Catalytic Reduction): EUI does not use a catalytic form ofNOx reduction. EPA 452/B-02-001 does not yethave
a sectionthatis applicable to close-coupled overfire airNOx combustion control. viii. Design control efficiency (%): A design control efficiency was not specifiedin the design manual ofthe overfire air control system, However, acurrent control efficiencyhave been estimatedto be 33%. (Based on the averageNOx emissionrates calculated using AP-42 emissionrate of0.60 lb/mmbtu before installation ofthe control system compared with the manufacturer's guaranteed NOx rate of0.40 lb NOx/MMBtu providedin the ABB Tuning Report. The efficiencyhas been confirmed with measured values. Note: 0.40 lb NOx/MMBtu is also the maximum allowable NOx emissionrate in the MT DEQ air permit. ix. 2007 Average Controlled NOx Emissions (lb/hr): 229.27 lbs/hr [Source: Calculations based on 2007 annual emissions inventory data]

c. S02Control TechnologyInformation: i. Type ofS02Control Technology: FloodedDisc Wet Scrubber [Source: 1996 Title V App, Section 6] ii. Make/Model ofS02 Control Technology: Research

- Cottrell/not specified [Source: 1996 Title VApp, Section 6] iii. YearInstalled: 1975 [Source: 1996 Title V App, Section 6] iv. Installed CostofControl Device ($/yr): $14,779,668 in 2008 dollars. The installed cost ofthe control device from 1975 and 1976 dollars was escalatedto 2008 dollars using the Chemical Engineering Plant CostIndex. [Source: accounting]
v. DirectAnnual CostofControl Device ($/yr): (2008 Costs) -O&M: $24,911.27 (Approximate cost ofoutage cleaning and I&C maintenance.) [Source: accounting] -Chemicals: $36,452.90 (Cost of 142.68 tons oflime including delivery.) [Source: accounting] -Waste Disposal: $180,000 (Approximate annual cost of scrubberpondmaintenance and ash disposal.) [Source: accounting] -Power: $123,134.18 (Total scrubberpower consumption plus halfthe ID fan powerconsumption for 2008 at $27. 14/MW) [Source: historical operation and accounting] vi. Expected life ofequipment: Not specified in the original design plans and specifications. There are currentlyno plans or schedule for removing the existing control equipment from service.

6vii. Relevant sizing information (Please provide information sufficient to apply the EPA AirPollution Control Cost Manual- Sixth Edition (EPA 452/B-02-001) Section 5 - SOz and Acid Gas Controls Section 5.2

- Post-Controls Chapter 1 - Wet Scrubbers for Acid Gas):

-Waste gas flow rate (acfm): 168,930 acfm

- 313,730 acfm [Source: Scrubber Operating Manual, Section 4] -Waste gas composition and concentration ofthe pollutants in the gas stream: 378 PPM -1691 PPM SOz [Source: Scrubber Operating Manual, Section 4] -Solvent flow rate (gpm): 2200

- 3700 gpm [Source: Scrubber Operating Manual, Section 4] -Properties ofthe pollutant, waste gas and solvent: diffusivity, viscosity, density and molecularweight The properties ofthe pollutant, waste gas and solvent are currently unknown. viii. Design control efficiency (%): The original design control efficiency is 15% or greater; the actual control efficiencyhas been demonstrated to be approximately 60%. [Source: Scrubber Operating Manual, Section 3, and actual emissions measurement] ix. 2007 Average Controlled SOz Emissions (lb/hr): 306.39 lbs/hr [Source: Calculations based on the 2007 annual emissions inventory data]

Thefollowing information shouldbe completedusing datafor theyear2002. 

## If informationfor2002 is notrepresentative of currentoperations (for example, 

## if this unit is no longer using naturalgas), provide informationfor a representativeyearand provide reasonsfor why the alternativeyear is more representative than 2002.

4: Fuel Information: Informationprovided is for year 2002.
Heating Sulfur Ash 

# I Amount of Value of Max Fuel Content Content, Fuel Type Fuel Fuel Firing Rate of Fuel of Fuel Liqnite 283,202 Tons 6658 Btu/lb 46.8 Tons/hr 0.51% 9.30% Pipeline Natural 667.75 0.02 Gas 14133DKT 1200 Btu/cf DKT/hr grief 0%

7