## North Dakota State Implementation Plan

for Regional Haze

A Plan for Implementing the Regional Haze Program R equirements

of Section 308 of 40 CFR Part 51, Subpart P - Protecti on of Visibility

North Dakota Department of Health Adopted: February 24, 2010

Division of Air Quality Air Pollution Control Program North Dakota Department of Health

918 East Divide Avenue Bismarck, North Dakota 58501-1947 Telephone 701-328-5188

Terry Dwelle, M.D., M.P.H.T.M.

State Health Officer

Terry O’Clair, P.E.

Director

## APPROVAL PAGE

North Dakota State Implementation Plan for Regional Haze

North Dakota Department of Health, Environmental Health Section, Division of

Air Quality.

Approval by 

### the following North Dakota Department of Health Management

Personnel:

L. 

### David Glatt, E.,

Environmental Hea Date

i 

### Date

Adopted for the North Dakota Department of Health

Terry e, M.D., M.P.H.T.M. Date

Sta· Health Officer

North Dakota Department of Health

11iii 

## Table of Contents

Page No.

Approval Page

i Governor’s Submittal Letter 1

ii Executive Summary 2

1. Purpose/Legal Authority 3

2. Overview 4

2.1 Introduction 4 2.2 Visibility Impairment 8 2.3 Description of North Dakota’s Class I Areas 8 2.4 Class I Areas in Other States Impacted by Nort h Dakota Sources 9 2.5 Programs to Address Visibility Impairment 11 2.6 Reasonable Progress Toward the 2064 Visibility Goals 14

3. Plan Development and Consultation 16 3.1 Consultation with Federal Land Managers (FLM) 16 3.1.1 FLM Comments Provided During 60 Day Comment Period 16 3.1.2 Response to FLM Comments 16

3.1.3 FLM Comments Provided on BART Portion of SI P in 2008 16

3.2 Consultation with EPA 17

3.3 Consultation with Other States 17 3.4 Regional Planning Consultation 18

3.5 Consultation with Tribes 18

3.6 Other Consultation 18

4. Monitoring Strategy and Other Implementation Pla n Requirements 19 4.1 RAVI Monitoring Strategy in Current North Dako ta Long Term Strategy 19 4.2 Regional Haze Visibility Impairment Monitoring Strategy and Other 20 Implementation Plan Requirements 4.3 Overview of the IMPROVE Monitoring Network 25

5. Baseline and Natural Visibility Conditions and U niform Rate of Progress for 30

North Dakota Class I Areas

5.1 The Deciview 30 5.2 Baseline Visibility Conditions 30 5.3 Natural Visibility Conditions 33 5.4 Uniform Rate of Progress 35

6. Sources of Visibility Impairment in North Dakota Class I Areas 38

6.1 Introduction 38

6.2 Emissions in North Dakota 38

6.3 Emissions from Other States and Canadian Provi nces 42iv

Page

7. Best Available Retrofit Technology (BART) 56

7.1 Introduction 56

7.1.1 Overview of Paragraph 51.308(e) of the Federa l Regional Haze 56 Regulation - Best Available Retrofit Technology (B ART) Requirements for Regional Haze Visibility Impairme nt 7.1.2 Visibility-Impairing Pollutants of Concern 58

7.1.3 BART Identification Process 59 7.1.4 CALPUFF Screening Model Protocol 62 7.1.5 Screening Impact Threshold 62 7.2 BART-Eligible Sources in North Dakota 63 7.3 Determination of BART-Eligible Sources Subject to BART 65 7.3.1 Sources Subject to BART 65

7.3.2 Exclusion of Tesoro Mandan Petroleum Refine ry 67 7.3.3 Exclusion of American Crystal Sugar Drayton Refinery 67

7.3.4 Exclusion of Montana Dakota Utilities Heskett Unit No. 2 67 7.4 Determination of BART Requirements for Subject -to-BART Sources 68 7.4.1 Company BART Analyses 68 7.4.2 Department BART Determinations 69 7.4.3 Summary of Emission Reductions 77

7.5 Air Pollution Control Permits to Construct for Subject-to-BART Sources 77

7.5.1 Enforceable Emission Limits 78 7.5.2 Monitoring, Recordkeeping, and Reporting Re quirements 78 7.5.3 Operating and Maintenance Requirements 79 7.5.4 Compliance Date 79

8. Visibility Modeling 80

8.1 Introduction 80 8.2 Regional Haze Metrics 83 8.3 Projection of Future Visibility 86 8.4 WRAP Visibility Modeling Methodology 88 8.5 NDDoH Visibility Modeling Methodology 90 8.5.1 Hybrid Modeling System 95 8.5.2 CALMET Input 96 8.5.2.1 Meteorological Data 98 8.5.2.2 Geophysical Data 102 8.5.2.3 CALMET Control File settings 102 8.5.3 CALPUFF Input 103 8.5.3.1 Emissions Inventory 106 8.5.3.2 Boundary Conditions 110 8.5.3.3 Ozone Background 111 8.5.3.4 Ammonia Background 111 8.5.3.5 Receptors 112 8.5.3.6 CALPUFF Control File Settings 113 8.5.4 POSTUTIL Input 116

8.5.5 CALHAZE 118 8.5.6 Hybrid System Used to Adjust WRAP CMAQ Mode ling Results 121v

Page

8.6 Modeling Process and Results 1 28 8.6.1 Hybrid CMAQ-CALPUFF Performance Evaluation 128 8.6.2 Results for Default EPA Methodology 135

8.6.2.1 Cumulative Results 135 8.6.2.2 Apportionment by Species 139 8.6.2.3 Apportionment by Source Group 147 8.6.2.4 Apportionment by Source Region 153

8.6.2.5 Conclusions 156 8.6.3 Weight of Evidence Options 157 8.6.3.1 Discounting the Impact of Canadian Sourc e 158

Emissions 8.6.3.2 Discounting the Impact of All Sources Lo cated 162

Outside of North Dakota 8.6.3.3 Use Default EPA Methodology with Zero No rth 164

Dakota Future Emissions 8.6.3.4 Base 20% Worst Days on Modeling Results Rather 167 Than IMPROVE Monitoring Data 8.6.3.5 Weight of Evidence Summary and Conclusio ns 168

9. Reasonable Progress Goals 172

9.1 Introduction 173

9.2 Establish Baseline and Natural Conditions 173

9.3 Determine the Glide Path or Uniform Rate of Pr ogress 173 9.4 Identify and Analyze the Measures Aimed at Ach ieving the 173 Uniform Rate of Progress

9.5 Additional Controls 177 9.5.1 Point Sources Contributing to Visibility Im pairment in the 177

North Dakota Class I Areas 9.5.2 Agricultural Tillage Operations 188 9.5.3 Smoke Management for Agricultural, Forest M anagement 190 and Prescribed Burning

9.5.4 Reserved 190 9.5.5 Oil and Gas Exploration and Production 190 9.6 Visibility Modeling and Weight of Evidence 192 9.7 Establish Reasonable Progress Goals 195

10. Long-Term Strategy 198 10.1 Long-Term Strategy Requirements 198

10.2 Consultation With Other States 198

10.3 Demonstration of Inclusion of Measures to Obtain RPGs 199

Established for Class I Areas

10.4 Documentation of the Technical Basis for Model ing, 199 Monitoring and Emissions Information 10.5 Identification of Anthropogenic Sources of Vis ibility Impairment 200vi

Page

10.6 Seven Factors That Must be Considered in Devel oping the LTS 200 10.6.1 Emission Reductions Due to Ongoing Air Poll ution 201 Control Programs 10.6.2 Measures to Mitigate the Impacts of Constru ction 202

Activities 10.6.3 Emission Limitations and Schedules for Comp liance 205 10.6.4 Source Retirement and Replacement Schedules 205 10.6.5 Smoke Management Techniques for Agriculture and 205 Forest Management 10.6.6 Enforceability of Emission Limitations and Control 207

Measures 10.6.7 The Anticipated Net Effect on Visibility Due to Projected 207 Changes in Point, Area and Mobile Source Emissions 10.7 Prevention of Significant Deterioration 208

11. Commitment to Consultation, Progress Reports, P eriodic Evaluations of 209 Plan Adequacy, and Future SIP Revisions

11.1 Future Consultation Commitments 209

11.1.1 FLM Consultation and Coordination 209

11.1.2 Tribal Consultation 210

11.1.3 Interstate Consultation and Coordination 210 11.2 Commitment to Progress Reports 211 11.3 Determination of Current Plan Adequacy 212

11.4 Commitment to Future SIP Revisions 213 11.5 Monitoring Strategy 214

11.6 Rules for Non-BART Point and Area Sources 215

12. Public Participation and Review Process 216 12.1 Summary of Comments Received during Public Co mment 216 Period/Hearing 12.2 Response to Public Comments 2 16 12.3 Revisions to the State Implementation Plan 216

12.4 Revisions to the BART Air Pollution Control P ermits to Construct 217vii 

## List of Appendices

Appendix A. BART Modeling Protocols and Analyses

A.1 Protocol for BART-Related Visibility Impairment Modeling Analyses in North

Dakota

A.2 Montana-Dakota Utilities Heskett Station Unit 2

A.3 Notification of Subject-to-BART Letters to BART -Eligible Sources

A.4 Coyote Station Permit to Construct

A.5 WRAP Methodology for Determining Baseline Visib ility Conditions

Appendix B. Department BART Determinations for Subj ect-to-BART Sources in North Dakota

B.1 Basin Electric Power Cooperative Leland Olds St ation Units 1 and 2

B.2 Great River Energy Coal Creek Station Units 1 a nd 2

B.3 Great River Energy Stanton Station Unit 1

B.4 Minnkota Power Cooperative Milton R. Young Stat ion Units 1 and 2

B.5 Best Available Retrofit Technology Selective Ca talytic Reduction Technical Feasibility Analysis for North Dakota Lignite

B.6 Selective Catalytic Reduction (SCR) Technical F easibility for M.R. Young

Station

Appendix C. Company BART Analyses and Supporting Information

C.1 Basin Electric Power Cooperative Leland Olds St ation Units 1 and 2

C.2 Great River Energy Coal Creek Station Units 1 a nd 2

C.3 Great River Energy Stanton Station Unit 1

C.4 Minnkota Power Cooperative Milton R. Young Stat ion Units 1 and 2

Appendix D. Air Pollution Control Permit to Constru ct for the Subject-to-BART Sources

D.1 Basin Electric Power Cooperative Leland Olds St ation Units 1 and 2

D.2 Great River Energy Coal Creek Station Units 1 a nd 2viii

D.3 Great River Energy Stanton Station Unit 1

D.4 Minnkota Power Cooperative Milton R. Young Stat ion Units 1 and 2

Appendix E. Modeling Protocol for Regional Progres s Goals in North Dakota, October 3, 2008

Appendix F. Public Hearing Record

F.1 Hearing Notice

F.2 Press Release

F.3 Affidavit of Publication

F.4 Invoice of Publication

F.5 Registration List of Attendees

F.6 Hearing Transcript

F.7 Certification of Hearing

F.8 Response to Public Comments

Appendix G. Legal Opinion of the Attorney General

Appendix H. NDAC Chapter 33-15-25 Regional Haze R equirements

Appendix I. Four Factors Analyses

I.1 Supplementary Information for Four-Factor Anal yses for Selected Individual

Facilities in North Dakota

I.2 Supplementary Information for Four Factors Ana lyses by WRAP States

Appendix J. Plan Development and Consultation

J.1 Consultation with Federal Land Managers

J.1.1 FLM Comments Provided on BART Portion of SI P During 60-day

Consultation Period in 2008

J.1.2 NDDoH Response to FLM Comments on BART Port ion of SIP in 2008

J.1.3 FLM Comments Provided During 60-Day Consult ation Period

J.1.4 NDDoH Response to FLM Commentsix

J.2 Consultation with Other States

J.2.1 Minnesota September 19, 2007 Memorandum

J.2.1 NDDoH August 22, 2008 Letter of Response

J.3 Consultation with EPA Region 8

J.3.1 EPA Comments Provided on BART Portion of SI P During 60-Day FLM

Consultation Period in 2008

J.3.2 NDDoH Response to EPA Comments on BART Port ion of SIP in 2008

J.4 Consultation with Tribesx 

## List of Tables

Table 2.1 - North Dakota Species Contribution (%) - 20% Worst Days 2000-2004

Table 4.1 - IMPROVE Monitoring Sites in North Dakot a

Table 4.2 - Additional non-IMPROVE Monitors

Table 5.1 - Baseline Visibility (Deciviews)

Table 5.2 - EPA Default Natural Visibility Conditio ns (Deciviews)

Table 5.3 - WRAP Calculated Natural Visibility Cond itions (Deciviews)

Table 5.4 - Improvement Necessary to Achieve Natura l Conditions (Deciviews)

Table 6.1 - North Dakota 2002 Emissions Inventory ( tons)

Table 6.2 - North Dakota Point Source Emission Inve ntory 2007

Table 6.3 - North Dakota 2018 Emission Inventory (t ons)

Table 6.4 - North Dakota Emission Inventory Plannin g Period Change

Table 6.5 - Nearby States 2002 Emissions (tons)

Table 6.6 - ND Sources Extinction Contribution 2000 -2004 20% Worst Days

Table 6.7 - Source Region Apportionment 20% Worst D ays

Table 6.8 - 2002 Canadian Emissions (tons)

Table 6.9 - Saskatchewan Power Plants 2002 Emission s (tons)

Table 7.1 - BART- Eligible Sources in North Dakota

Table 7.2 - Individual BART-Eligible Source Visibil ity Impact On Class I Areas

Table 7.3 - BART-Level Emissions Reductions from th e 2000-2004 Sulfur Dioxide Average

Table 7.4 - BART-Level Emissions Reductions from th e 2000- 2004 Nitrogen Oxides Average

Table 8.1 - WRAP RMC Source Categories

Table 8.2 - CMAQ-CALPUFF Area Source Categoriesxi

Table 8.3 - CALPUFF System Versions Applicable For Regional Haze Modeling

Table 8.4 - User-Defined and Non-IWAQM Settings for CALMET Control File

Table 8.5 - Monthly Ammonia Background Concentratio ns

Table 8.6 - User-Defined and Non-IWAQM Settings for CALPUFF Control File

Table 8.7 - 3-Step Ammonia Limiting Method

Table 8.8 - WRAP CMAQ RRF (Specific Day Option)

Table 8.9 - Hybrid CMAQ-CALPUFF Performance Evaluat ion - Observed and Predicted

Concentrations Year 2002

Table 8.10 - Hybrid CMAQ-CALPUFF Performance Evalua tion - Predicted to Observed

Ratios 2002

Table 8.11 - WRAP and NDDoH Visibility Modeling Res ults - Uniform Rate of Progress - Default EPA Methodology

Table 8.12 - Summary of WRAP CMAQ Visibility Projec tions for Worst 20% Days at TRNP

Table 8.13 - Summary of WRAP CMAQ Visibility Projec tions for Best 20% Days at TRNP

Table 8.14 - Summary of WRAP CMAQ Visibility Projec tions for Worst 20% Days at LWA

Table 8.15 - Summary of WRAP CMAQ Visibility Projec tions for Best 20% Days at LWA

Table 8.16 - Hybrid Modeling Results - Total North Dakota Contribution to 20% Worst Days Predictions

Table 8.17 - NDDoH Visibility Modeling Results 20% Worst Days - Weight of Evidence - Discounting Canadian Emissions

Table 8.18 - NDDoH Visibility Modeling Results 20% Worst Days - Weight of Evidence - Discounting All Out-of-State Sources

Table 8.19 - NDDoH Visibility Modeling Results 20% Worst Days - Weight of Evidence -

Zero Future North Dakota Emissions

Table 8.20 - NDDoH Visibility Modeling Results 20% Worst Days - Weight of Evidence Analysis Summary

Table 9.1 - Baseline and Natural Visibility Conditi ons

Table 9.2 - Visibility Improvement Requiredxii

Table 9.3 - North Dakota Sources of Sulfate and Nit rates 2000-2004

Table 9.4 - North Dakota Title V Sources Q/D Analys is

Table 9.5 - Sources Evaluated for Additional Contro ls

Table 9.6 - Remaining Sources Existing Conditions

Table 9.7 - Control Options Evaluated

Table 9.8 - Control Options Cost

Table 9.9 - Visibility Improvement and Cost Effecti veness

Table 9.10 - Remaining Useful Life

Table 9.11 - NDDoH Visibility Modeling Results 20% Worst Days EPA Methodology and Weight of Evidence Analysis Summary

Table 9.12 - Source Region Apportionment 20% Worst Days

Table 9.13 - Projected Change in Emissions 2002-201 8

Table 9.14 - Reasonable Progress Goals

Table 9.15 - Time Necessary to Achieve Natural Cond itions

Table 10.1 - Annual Average Emissions from Fire in North Dakota (2000-2004)

Table 10.2 - North Dakota Anthropogenic Fire Contri bution to the 20% Worst Daysxiii 

## List of Figures

Figure 2.1 - Map of United States Class I Areas

Figure 2.2 - Map of North Dakota Class I Areas

Figure 2.3 - CENRAP PSAT Modeled W20% 2002 BEXT

Figure 4.1 - Pictures of the IMPROVE Monitoring Sit e at Lostwood National Wilderness Area

Figure 4.2 - IMPROVE Sample Modules

Figure 4.3 - Comparison of Extinction (Mm -1 ), Deciview (dv), and Visual Range (km)

Figure 5.1 - Monitoring Data for Worst 20% Visibili ty Days TRNP

Figure 5.2 - Monitoring Data for Best 20% Visibilit y Days TRNP

Figure 5.3 - Monitoring Data for Worst 20% Visibili ty Days LNWA

Figure 5.4 - Monitoring Data for Best 20% Visibilit y Days LNWA

Figure 5.5 - Uniform Rate of Progress

Figure 5.6 - Glide slope for Worst 20% Visibility D ays TRNP

Figure 5.7 - Glide slope for Worst 20% Visibility D ays LNWA

Figure 6.1 - WRAP Source Region/Type Contributions to Sulfate on Worst 20% Visibility Days TRNP

Figure 6.2 - WRAP Source Region/Type Contributions to Nitrate on Worst 20% Visibility Days TRNP

Figure 6.3 - Potential Sources and Areas of Sulfur Oxide Emissions on Worst 20% Visibility Days 2000-2004 Baseline & 2018 PRPb - Class I Area - Theodore Roosevelt National Park

Figure 6.4 - Potential Sources and Areas of Nitroge n Oxide Emissions on Worst 20% Visibility Days 2000-2004 Baseline & 2018 PRPb - Class I Area - Theodore Roosevelt National Park

Figure 6.5 - Potential Sources and Areas of Organic Aerosol Emissions on Worst 20% Visibility Days 2000-2004 Baseline & 2018 PRPb - Class 1 Area - Theodore Roosevelt National Park

Figure 6.6 - Potential Sources and Areas of Element al Carbon Emissions on Worst 20% Visibility Days 2000-2004 Baseline & 2018 PRPb - Cl ass 1 Area - Theodore Roosevelt National

Parkxiv

Figure 6.7 - Potential Sources and Areas of Fine PM Emissions on Worst 20% Visibility Days

2000-2004 Baseline & 2018 PRPb - Class 1 Area - The odore Roosevelt National Park

Figure 6.8 - Potential Sources and Areas of Coarse PM Emissions on Worst 20% Visibility Days

2000-2004 Baseline & 2018 PRPb - Class 1 Area - The odore Roosevelt National Park

Figure 6.9 - WRAP Source Region/Type Contributions to Sulfate on Worst 20% Visibility Days

LNWA

Figure 6.10 - WRAP Source Region/Type Contributions to Nitrate on Worst 20% Visibility Days

LNWA

Figure 6.11 - Potential Sources of Sulfur Oxide Emi ssions on Worst 20% Visibility Days, 2000- 2004 Baseline & 2018 PRPb, Class I Area - Lostwood NWRW

Figure 6.12 - Potential Sources of Nitrogen Oxides Emissions on Worst 20% Visibility Days, 2000-2004 Baseline & 2018 PRPb, Class I Area - Lost wood NWRW

Figure 6.13 - Potential Sources and Areas of Organi c Aerosol Emissions on Worst 20% Visibility Days 2000-2004 Baseline & 2018 PRPb - Cl ass 1 Area - Lostwood Wilderness Area

Figure 6.14 - Potential Sources and Areas of Elemen tal Carbon Emissions on Worst 20% Visibility Days 2000-2004 Baseline & 2018 PRPb - Cl ass 1 Area - Lostwood Wilderness Area

Figure 6.15 - Potential Sources and Areas of Fine P M Emissions on Worst 20% Visibility Days

2000-2004 Baseline & 2018 PRPb - Class 1 Area - Los twood Wilderness Area

Figure 6.16 - Potential Sources and Areas of Coarse PM Emissions on Worst 20% Visibility Days 2000-2004 Baseline & 2018 PRPb - Class 1 Area - Lostwood Wilderness Area

Figure 6.17 - Sulphur Oxide (SO

x ) Emissions in Canada for 2002

Figure 6.18 - Nitrogen Oxides (NO

x ) Emissions in Canada for 2002

Figure 7.1 - BART-Eligible Sources and Class I Area s in North Dakota

Figure 8.1- WRAP CMAQ Domain and NDDoH CALPUFF Doma in

Figure 8.2 - Larger Point Sources and PSD Class I A reas

Figure 8.3 - IMPROVE 20% Worst Days - TRNP 2000

Figure 8.4 - Hybrid Interfacing of CMAQ and CALPUFF Modeling Systems

Figure 8.5 - CALPUFF 3-km Meteorological/Computatio nal Grid

Figure 8.6 - CALMET Surface / Upper Air Meteorologi cal Stationsxv

Figure 8.7 - CALMET Precipitation Stations

Figure 8.8 - NDDoH Domain - Locations of Larger Poi nt Sources and 36-km Area Source Grid

Figure 8.9 - NH 3 Emissions Density for North Dakota Counties and Ad joining Canadian

Provinces

Figure 8.10 - Illustration of Visibility Improvemen t Using EPA Default Glide Path and US Source Adjusted Glide Path for Sulfate

Figure 8.11 - Observed and Predicted Time Series TR NP NO 3 2002

Figure 8.12 - TRNP Uniform Rate of Progress - EPA D efault Methodology

Figure 8.13 - LWA Uniform Rate of Progress - EPA De fault Methodology

Figure 8.14 - IMPROVE 20% Worst Days - TRNP 2004

Figure 8.15 - IMPROVE 20% Worst Days - LWA 2004

Figure 8.16 - Hybrid Modeling Results - Source Grou p Contributions to 20% Worst Day

SO 4 at TRNP (Base and Future)

Figure 8.17 - Hybrid Modeling Results - Source Grou p Contributions to 20% Worst Day

SO 4 at LWA (Base and Future)

Figure 8.18 - Hybrid Modeling Results - Source Grou p Contributions to 20% Worst Day

NO 3 at TRNP (Base and Future)

Figure 8.19 - Hybrid Modeling Results - Source Grou p Contributions to 20% Worst Day

NO 3 at LWA (Base and Future)

Figure 8.20 - WRAP Modeling Results - Source Region Contributions to 20% Worst Day

SO 4 at TRNP (baseline)

Figure 8.21 - WRAP Modeling Results - Source Region Contributions to 20% Worst Day

NO 3 at TRNP (baseline)

Figure 8.22 - WRAP Modeling Results - Source Region Contributions to 20% Worst Day

SO 4 at LWA (baseline)

Figure 8.23 - WRAP Modeling Results - Source Region Contributions to 20% Worst Day

NO 3 at LWA (baseline)

Figure 8.24 - Uniform Rate of Progress - EPA Defaul t Methodology and Canada Sources

Discountedxvi

Figure 8.25 - Uniform Rate of Progress - EPA Defaul t Methodology and Non-ND Sources

Discounted

Figure 8.26 - TRNP Uniform Rate of Progress - EPA D efault Methodology and NDDoH Weight of Evidence

Figure 8.27 - LWA Uniform Rate of Progress - EPA De fault Methodology and NDDoH Weight of Evidence

Figure 9.1 - Sources and Areas of Potential Organic Carbon Emissions in Worst 20% Visibility Days - Theodore Roosevelt National Park

Figure 9.2 - Sources and Areas of Potential Organic Carbon Emissions in Worst 20% Visibility Days - Lostwood Wilderness Area

Figure 9.3 - TRNP Species Apportionment 20% Worst D ays

Figure 9.4 - LWA Species Apportionment 20% Worst Da ysxvii 

## List of Acronyms

AIRS Aerometric Information Retrieval System AQS EPA’s Air Quality System AVS Antelope Valley Station ASOFA Advanced separated overfire air BADL Badlands National Park, SD Bag Baghouse BART Best Available Retrofit Technology

B ext Light extinction (typically measured in inverse m egameters: 1/Mm or Mm -1)
BHP Brake Horsepower BOWA Boundary Waters Canoe Area Wilderness Area, MN BRCA Bryce Canyon National Park, UT BRID Bridger Wilderness, WY

Btu British thermal unit CAA Clean Air Act (42 United States Code Sections 7 401, et seq) CABI Cabinet Mountains Wilderness Area, MT CALPUFF Multi-layer, multi-species, non-steadystate , puff, long range transport dispersion

modeling system CAMx Comprehensive Air Quality Model with extensio ns CANY Canyonlands National Park, UT

CEM Continuous emissions monitor CENRAP Central Regional Air Planning Association CFR Code of Federal Regulations CM Coarse mass (PM 2.5 mass subtracted from PM 10 mass) CMAQ Community Multiscale Air Quality model CTIC Conservation Technology Information Center

D Distance in kilometers DGC Dakota Gasification Company DOA United States Department of Agriculture DOI United States Department of the Interior

Dv deciview

∆ dv Change in deciviews

EC Elemental carbon EDMS Emissions Data Management System EGU Electrical Generating Unit EPA United States Environmental Protection Agency ESP Electrostatic precipitator FGD Flue gas desulfurization FLM Federal Land Manager FM Fine mass (PM 2.5 mass) FR Federal Register FS United States Forest Service (DOA) FWS United States Fish and Wildlife Service (DOI) GAMO Gates of the Mountains Wilderness Area, MT GCVTC Grand Canyon Visibility Transport Commission GPSP Great Plains Synfuels Plant GRSA Great Sand Dunes Wilderness Area, COxviii

HEGL Hercules - Glades Wilderness Area, MO Hp Horsepower IMPROVE Interagency Monitoring of Protected Visual Environments IPM Integrated Planning Model ISLE Isle Royale National Park, MI

km Kilometers LADCO Lake Michigan Air Directors Consortium

lb Pounds

lb/10 6 Btu Pounds per million British thermal units

LEC Low Emission Combustion LOST Lostwood National Wildlife Refuge Wilderness A rea, ND ln Natural logarithm

LNB Low NO

x burner LTPD Long Tons Per Day LTS Long Term Strategy LWA Lostwood National Wildlife Refuge Wilderness Ar ea, ND MACT Maximum Achievable Control Technology MELA Medicine Lake National Wildlife Refuge Wildern ess Area, MT MEVE Mesa Verda National Park, CO MI Michigan MING Mingo Wilderness Area, MO Mm Megameters

MN Minnesota MOZI Mount Zirkel Wilderness Area, CO MPCA Minnesota Pollution Control Agency

MT Montana MRPO Midwest Regional Planning Organization NAAQS National Ambient Air Quality Standards

ND North Dakota NDAC North Dakota Administrative Code (state rules) NDCC North Dakota Century Code (state laws) NDDoH North Dakota Department of Health NEI National Emissions Inventory

NESHAP National Emission Standards for Hazardous Ai r Pollutants

NH 3 Ammonia

NO 3 Nitrate

NO

x Oxides of nitrogen or nitrogen oxides NOAB North Absaroka Wilderness, WY NPS National Park Service (DOI)

NSPS New Source Performance Standard OC Organic carbon

OFA Overfire air

PM Particulate matter PMC Coarse particulate matter, PM 10 – PM 2.5 PM
coarse Coarse particulate matter, PM 10 – PM 2.5 PMF Fine particulate matter, PM 2.5 PM fine Fine particulate matter, PM 2.5xix

PM 2.5 Fine particulate matter; particulate matter with an aerodynamic diameter less than

or equal to a nominal 2.5 micrometers as measured b y an EPA approved reference

method

PM 10 Particulate matter with an aerodynamic diameter l ess than or equal to a nominal

10 micrometers as measured by an EPA approved refer ence method POA Primary Organic Aerosol PSAT Particulate Matter Source Apportionment Techno logy PSD Prevention of Significant Deterioration Q Emission rate in tons per year RAVI Reasonably Attributable Visibility Impairment RPG Reasonable Progress Goal RHR Regional Haze Rule/Regulation ROMO Rocky Mountain National Park, CO SCR Selective catalytic reduction SENE Seney National Wildlife Refuge Wilderness Are a, MI

SD South Dakota SD Spray dryer SIP State Implementation Plan SMOKE Sparse Matrix Operator Kernel Emissions SMP Smoke Management Plan SNCR Selective non-catalytic reduction

SO 2 Sulfur dioxide

SO 4 Sulfate

SO

x Sulfur oxides SRU Sulfur recovery unit THRO Theodore Roosevelt National Park, ND TRNP Theodore Roosevelt National Park, ND TPY tons per year; also listed as tpy TSD Technical Support Document TSS WRAP Technical Support System UCR University of California at Riverside ULBE UL Bend National Wildlife Refuge Wilderness Ar ea, MT URP Uniform rate of progress

USC United States Code VIEWS Visibility Information Exchange Web System VISTAS Visibility Improvement State and Tribal Asso ciation of the Southeast VOC Volatile organic compounds VOYA Voyageurs National Park, MN VR Visual Range WEMI Weminuche Wilderness Area, CO WICA Wind Cave National Park, SD WRAP Western Regional Air Partnership

WS Wet scrubber YELL Yellowstone National Park, MT & WY ZION Zion National Park, UTEnclosures

C: L. David Glatt, Chief, Environmental Health, ND Department of Health Terry O'Clair, Director, Division of Air Quality, ND Department of Health

Gail Fallon, Environmental Protection Agency, Region 8

38:47:56

600 E Boulevard Ave.

Bismarck! ND 58505-0001

Phone: 701.328.2200

Fax: 701.328.2205

www.nd.gov 

# -
..... State**of-··~··** ! 

# I 

# North Dakota 

# I f Office of the Governor



### John 

### Hoeven I Governor 

### I

March 3, 2010

Lisa P. Jackson, Administrator

United States Environmental Protection Agency

c/o Ms. Carol Rushin Acting Regional Administrator

United States Environmental Protection Agency, Region 8

1595 Wynkoop Street Denver, CO 80202-1129

Re: North Dakota State Implementation Plan for Regional Haze

Dear Administrator Jackson:

The State of North Dakota is hereby submitting an amendment to the State Implementation Plan (SIP) to address the requirements for Regional Haze of Section 308 of

40 CFR Part 51, Requirements for Preparation, Adoption, and Submittal ofImplementation Plans, Subpart P - Protection of Visibility. This SIP amendment was prepared by the North

Dakota Department of Health, Air Quality Division.

Seven steam electric generating units in North Dakota have been identified as being subject to the BART requirements of 40 CFR 51.308(e). The installation of BART on these

sources will result in a reduction of 98,618 tons per year of sulfur dioxide emissions and a reduction of 21,137 tons per year of nitrogen oxides emissions from the 2000-2004 average emissions. These reductions will significantly improve visibility in North Dakota's Class I

areas as well as those in surrounding states.

With this submission, I am requesting the United States Environmental Protection Agency's approval of this SIP amendment.

If you have any questions regarding this submittal, please contact Terry O'Clair, P.E., Director, Division of Air Quality, North Dakota Department of Health, at 701-328-5178. 

# I

Sincerely, 

# I



# I2



## ii Executive Summary

This document comprises the State of North Dakota’s State Implementation Plan (SIP) submittal to EPA to meet the requirements of Section 308 of t he Regional Haze Regulation (40 CFR Part 51, Subpart P, Section 51.308). Adoption of the Nor th Dakota State Implementation Plan For Regional Haze amends the Implementation Plan for th e Control of Air Pollution for the State of

North Dakota.

Section 1 describes the purpose of and legal author ity of the SIP. Section 2 provides introductory and background information on the federal regional haze law and regulation, visibility impairment, a description of North Dakota’s Class I areas and reasonable progress towards the 2064 visibility goals. Section 3 describes plan dev elopment and consultation with federal land managers, other states, the EPA, and stakeholders. Section 4 describes the North Dakota monitoring strategy and commitments for future moni toring. Section 5 describes baseline and natural visibility conditions for the North Dakota Class I areas and the uniform rate of progress

for each Class I area. Section 6 describes the sour ces of visibility impairment at North Dakota = s Class I areas. Section 7 describes and provides the results of the Best Available Retrofit Technology (BART) process including the Air Polluti on Control Permits to Construct issued to the seven power plant boilers subject to BART. Sec tion 8 describes the CMAQ and CALPUFF modeling used in developing the SIP. Section 9 desc ribes the process for determining the reasonable progress goals for North Dakota’s Class I areas and what they are. Section 10 describes the long term strategy. Section 11 descr ibes the commitments to future consultation, progress reports, periodic evaluations of SIP adequ acy, and future SIP revisions. Section 12 summarizes the public participation and review proc ess and the revisions made subsequent to the public hearing for the SIP. Appendices at the end of this document provide additional information on BART and reasonable progress modelin g protocols, company BART analyses, Department BART determinations, the BART Air Pollut ion Control Permits to Construct, FLM and EPA comments during the 60-day FLM comment peri od, the public hearing record, Department responses to FLM, EPA, and public commen ts, consultation with the FLMs, EPA and other states, the legal opinions of the Attorney Ge neral, and the State BART rule.

The North Dakota BART determination process identif ied seven electrical generating units that are subject to the BART requirements. The installat ion of new control devices or modifications to existing control devices will reduce sulfur dioxide emission from point sources in the state by 98,618 tons per year and nitrogen oxides emissions by 21,139 tons per year. The BART reductions must be implemented no later than five y ears after EPA approves this SIP. The anticipated date of implementation is 2013. These r eductions are expected to make a significant improvement in visibility in the affected Class I a reas. Total sulfur dioxide emissions in North Dakota are expected to decline by 105,729 tons per year (60%) and nitrogen oxides emissions by 57,970 tons per year (25%) during this planning per iod.

The 2018 reasonable progress goals for the twenty p ercent worst days in the North Dakota Class I

areas have been established at 16.9 deciviews for e ach unit of Theodore Roosevelt National Park (TRNP) and 18.9 deciviews at Lostwood Wilderness Ar ea (LWA). The analyses conducted by the North Dakota Department of Health (NDDoH) and t he Western Regional Air Partnership (WRAP) indicates there will be no degradation durin g the 20% best days.3



## 1. Purpose / Legal Authority

The purpose of this submittal is to address the Sta te Implementation Plan requirements for the State of North Dakota found in Paragraph 40 CFR 51. 308, Regional Haze Program Requirements, of 40 CFR Part 51 Subpart P - Protection of Visibil ity.

The North Dakota Department of Health (the Departme nt), the agency designated to administer and coordinate a statewide program of air pollution control, has general legal authority under North Dakota Century Code Sections 23-25-03 and 28- 32-02 to adopt and enforce rules for visibility protection including regional haze visib ility impairment.

The Department adopted rules in 1987 to implement S ections 40 CFR 51. 300 - 307 (NDAC Chapter 33-15-19 Visibility Protection, Effective d ate October 1, 1987) and in 2006 to implement Paragraph 40 CFR 51.308(e) (NDAC Chapter 33-15-25 R egional Haze Requirements, Effective Date January 1, 2007).

It is the legal opinion of the North Dakota Attorne y General that the State Implementation Plan (SIP) is legal, valid and the Air Pollution Control Permits to Construct for the BART sources, and the Coyote Station, included within the SIP in Appe ndix D and Appendix A.4 have the force and effect of law. A copy of the Attorney General opini on is contained in Appendix G.4



## 2. Overview

2.1 Introduction

The Clean Air Act (CAA) defines the general concept of protecting visibility in each of the 156 Mandatory Class I Federal Areas across the nation a s shown in Figure 2.1. Section 169A from the 1977 CAA set forth the following national visibilit y goal:

“Congress hereby declares as a national goal the pr evention of any future, and the remedying of any existing, impairment of visibility in mandatory Class I Federal areas which impairment results from man-made air pollutio n.”

The federal visibility regulations (40 CFR Part 51, Subpart P - Visibility Protection Section 51.300 - 309) detail a two-phased process to determ ine existing impairment in each of the Class I areas, how to remedy such impairment, and how to es tablish goals to restore visibility to “natural conditions” by the year 2064 in each of these areas . The federal regulations require states to prepare a SIP to: include a monitoring strategy, ad dress existing impairment from major stationary facilities (Reasonably Attributable Visi bility Impairment), prevent future impairment from proposed facilities, address Best Available Re trofit Technology (BART) for certain stationary sources, consider other major sources of visibility impairment, calculate baseline, current and natural visibility conditions, consult with the Federal Land Managers (FLMs) in the development or change to the SIP, develop a long-te rm strategy to address issues facing the state, set and achieve reasonable progress goals for each Class I area, and review the SIP every five

years.

EPA promulgated regulations to implement the statut e in December, 1980. Following litigation, a court settlement divided visibility protection in to two phases.

Phase 1 of the visibility program, also known as Re asonably Attributable Visibility Impairment (RAVI), addresses impacts in Class I areas by estab lishing a process to evaluate source specific visibility impacts, or plume blight, from individua l sources or small groups of sources. Part of that process relates to the evaluation of sources p rior to construction through the Prevention of Significant Deterioration (PSD) permit program for major stationary sources. The plume blight part of the Phase 1 program also allows for the eva luation, and possible control, of reasonably attributable impairment from existing sources. Nor th Dakota has developed, and EPA approved, a SIP for Phase 1 of the visibility program. The Ph ase 1 rule is NDAC 33-15-19, Visibility

Protection.

Section 169B was added to the Clean Air Act Amendme nts of 1990 to address regional haze. Since regional haze does not respect state and trib al boundaries, the amendments authorized EPA to establish visibility transport regions as a way to combat regional haze.

Phase 2 of the visibility program addresses regiona l haze. This form of visibility impairment focuses on overall decreases in visual range, clari ty, color, and ability to discern texture and details in Class I areas. The responsible air pollu tants can be generated in the local vicinity or5

transported by the wind often many hundreds or even thousands of miles from where they originated. For technical and legal reasons the sec ond part of the visibility program was not implemented in regulation until 1999.

In July 1999, the EPA finalized the Regional Haze R ule (RHR) requiring States to adopt State Implementation Plans to address this aspect of visi bility impairment in the Class I areas. The rule was amended in July, 2005. Under the current rules the Regional Haze SIP was to be submitted to the EPA by December 17, 2007.

The two key requirements of the regional haze progr am are:

1. Improve visibility for the most impaired days, and 2. Ensure no degradation in visibility for the leas t impaired days.

Though the national visibility goals are to be ulti mately achieved by the year 2064, the SIP seeks to meet the two requirements stated above by 2018, the first planning period established by the

federal rule.

Pursuant to the requirements of 51.308(a) and (b), the SIP is intended to meet the requirements

of EPA = s Regional Haze rules that were adopted to comply with requirements set forth in

Section 169B of the Clean Air Act. Elements of this SIP are to address:

• The core regional haze program requirements pursuan t to 40 CFR 51.308(d),

• The Best Available Retrofit Technology (BART) requi rements of 40 CFR 51.308(e),

• The requirements for comprehensive periodic revisio ns of regional haze SIPs of 40 CFR 51.308(f),

• The requirements for periodic reports describing pr ogress towards the reasonable progress goals of 40 CFR 51.308(g),

• The requirement for determination of the adequacy o f the existing implementation plan of 40 CFR 51.308(h), and

• The requirements for State and Federal Land Manager coordination of 40 CFR 51.308(i).

In addition, 40 CFR 51.308(c) of the original July 1999 regulation provided options for a regional planning process to allow states to develo p a coordinated approach to regional haze. In March 1999, North Dakota became a member of the Wes tern Regional Air Partnership (WRAP), the regional planning organization serving 13 weste rn states, tribes and federal agencies. Section 51.308(c) was deleted on July 6, 2005 when the BART Guidelines were added to the regional

haze rule.6 Figure 2.1 - Map of United States Class I AreasFigure 2. 2

– Map of North Dakota Class I Areas

78



### 2.2 Visibility Impairment

Most visibility impairment occurs when pollution in the form of small particles scatters or absorbs light. Air pollutants come from a variety o f natural and anthropogenic sources. Natural

sources can include windblown dust and smoke from w ildfires. Anthropogenic sources can include motor vehicles, electric utility and indust rial fuel burning and manufacturing operations. More pollutants mean more absorption and scattering of light, which reduce the clarity and color of a scene. Some types of particles such as sulfate s and nitrates, scatter more light, particularly during humid conditions. Other particles like eleme ntal carbon from combustion processes are highly efficient at absorbing light. Commonly, the receptor is the human eye and the object may be a single viewing target or a scene.

In the 156 Class I areas across the country, visual range has been substantially reduced by air pollution. In eastern parks, average visual range h as decreased from 90 miles to 15-25 miles. In the West, visual range has decreased from an averag e of 140 miles to 35-90 miles.

Some haze causing particles are directly emitted to the air. Others are formed when gases emitted to the air form particles as they are carried many miles from the source of the pollutants. Some haze-forming pollutants are also linked to human he alth problems and other environmental damage. Exposure to very small particles in the air has been linked with increased respiratory illness, decreased lung function and premature deat h. In addition, particles such as nitrates and sulfates contribute to acid deposition potentially making lakes, rivers and streams unsuitable for some forms of aquatic life and impacting flora in t he ecosystem. These same acid particles can also erode materials such as paint, buildings or ot her natural and man-made structures.



### 2.3 Description of North Dakota’s Class I Areas

The Class I areas in North Dakota include: the Theo dore Roosevelt National Park (TRNP) which consists of three separate, distinct units and the Lostwood National Wildlife Refuge Wilderness Area (LWA). The North Dakota Class I Areas are show n on Figure 2.1 and Figure 2.2.

Theodore Roosevelt National Park is located within Billings and McKenzie Counties in North

Dakota. The colorful badlands and Little Missouri R iver of western North Dakota provide the scenic backdrop to the park which memorializes the 26 th president for his enduring contributions

to the conservation of our nation’s resources. The park contains 70,447 acres divided among three separate units: South Unit, Elkhorn Ranch and North Unit and is managed by the National Park Service. The park is comprised of badlands, o pen prairie and hardwood draws that provide habitat for a wide variety of wildlife species incl uding bison, prairie dogs, elk, deer, big horn sheep and other wildlife. The Little Missouri River passes through the three units of the park.

Lostwood National Wildlife Refuge Wilderness Area i s located in Burke County in the northwestern part of the State. Created by an act o f Congress in 1975, the wilderness covers an area of 5,577 acres. It is contained within Lostwoo d National Wildlife Refuge and is managed by

the U.S. Fish and Wildlife Service. Lostwood Nation al Wilderness Area is designated to preserve9

a region well known for numerous lakes and mixed gr ass prairie. The wilderness ensures that the finest duck and waterfowl breeding region in North America remains wild and unimproved.



### 2.4 Class I Areas in Other States Impacted by North Dakota Sources

In accordance with 40 CFR 51.308, emissions sources within North Dakota have or may be reasonably expected to have impacts on the followin g Class I Areas: Boundary Waters Canoe Area Wilderness Area (BOWA) and Voyageurs National Park (VOYA) in Minnesota, Isle Royale National Park (ISLE) and Seney National Wil dlife Refuge Wilderness Area (SENE) in Michigan, Medicine Lake National Wildlife Refuge Wi lderness Area (MELA) and U. L. Bend National Wildlife Refuge Wilderness Area ((ULBE) in Montana, and Badlands National Park (BADL) and Wind Cave National Park (WICA) in South Dakota. As shown in Table 2.1 and Figure 2.1, sources in North Dakota have only a sma ll impact on out-of-state Class I areas. For Class I areas that are more distant, the impact wil l be even smaller. Impacts from emission sources in North Dakota contribute 5 percent or mor e of the total 2002 extinction (Bext) in the above Class I areas except those in Michigan and BO WA. A 5 percent or larger contribution is considered a significant contribution.

Table 2.1

North Dakota Species Contribution (%) 20% Worst Days

2000-2004

Class I Area Sulfate Nitrate OC EC PMF PMC Sea Salt

TRNP 21 19 12 29 44 45 0

LWA 18 13 23 35 28 32 0

Badlands 8 10 2 4 3 3 0

Wind Cave 8 8 1 2 4 3 0

U.L. Bend 9 5 1 1 1 1 0

Medicine Lake 11 7 9 15 17 16 0

Gates of the Mountains < 1 < 1 < 1 < 1 < 1 < 1 0

North Absaroka 1 1 < 1 < 1 < 1 < 1 0
Voyageurs 6 9 3* 6* 15* 22* 0
Boundary Waters* 3 10 2 4 10 7 0
Isle Royale* 2 4 1 2 6 6 0
Seney* 1 3 <1 <1 2 4 0

Based on WRAP’s tracer analyses (SO 4 and NO 3 ) and weighted emissions potential (WEP) analyses unless otherwise noted.

*Based on CENRAP data.10

From CENRAP’s PSAT analysis, North Dakota’s contrib ution to total extinction (20% worst days in base year 2002) at the nearby Class I areas is shown in Figure 2.3.

Figure 2.311



### 2.5 Programs to Address Visibility Impairment

North Dakota and EPA have many existing emission co ntrol programs/rules to improve and protect visibility in Class I areas.

North Dakota adopted and EPA approved a SIP for Pha se 1 of the visibility program. This program addresses major source PSD permitting, sour ce specific haze and plume blight aspects of visibility impairment. The Phase 1 rule is NDAC 33-15-19, Visibility Protection. It has an effective date of October 1, 1987.

North Dakota adopted NDAC 33-15-25, Regional Haze R equirements in 2006 with an effective date of January 1, 2007. This rule implements the B ART provisions of the federal RHR.

North Dakota has several other emission control pro grams/rules that while not specifically written to address visibility impairment, do addres s visibility and work to improve and protect visibility in Class I areas. These include:

NDAC Chapter 33-15-02, Ambient Air Quality Standard s, Section 33-15-02-03. Air quality guidelines. This rule states in part:

“In keeping with the purpose of these ambient air quality standards, the quality should be

such that:

4. Visibility will be protected.

7. Natural scenery will not be obscured.”

NDAC Chapter 33-15-04, Open Burning Restrictions. S ection 33-15-04-02. Permissible open burning. This rule states in part:

“2. The following conditions apply to all types of permissible burning listed in

subsection 1.

h. Except in an emergency, burning may not be co nducted is such proximity of any Class I area, as defined in chapter 33-15- 15, that the ambient air of

such area i s adversely impacted.

i. Except in an emergency, the visibility of any Class I area cannot be adversely impacted as defined in chapter 33-15-1 9.”

NDAC Chapter 33-15-15, Prevention of Significant De terioration of Air Quality, requires that a visibility analysis be prepared in accordance with chapter 33-15-19 as a part of the requirements for a PSD permit to construct.

NDAC Chapter 33-15-17. Restriction of Fugitive Emis sions. Section 33-15-17-02 Restriction of fugitive particulate emissions. This rules states i n part: “No person shall emit or cause to be12

emitted into the ambient air from any source of fug itive emissions as specified in section 33-15- 17-01 any particulate matter which:

5. Would have an adverse impact on visibility, as defined in chapter 33-15-19, on any federal class I area.”

In addition to the above programs, the following em ission control programs/rules, which do not specifically address visibility impairment, control the emission of pollutants that cause or contribute to visibility impairment:

NDAC Chapter 33-15-03 Restriction of Emission of V isible Air Contaminants NDAC Chapter 33-15-05 Emissions of Particulate Mat ter Restricted NDAC Chapter 33-15-06 Emissions of Sulfur Compound s Restricted NDAC Chapter 33-15-07 Control of Organic Compounds Emissions NDAC Chapter 33-15-08 Control of Air Pollut ion from Vehicles and Other Internal Combustion Engines NDAC Chapter 33-15-12 Standards of Performance fo r New Stationary Sources NDAC Chapter 33-15-14 Designated Air Contaminant Sources, Permit to Construct, Minor Source Permit to Operate, Title V Permit to Operate NDAC Chapter 33-15-20 C ontrol of Emissions from Oil and Gas Well Productio n Facilities NDAC Chapter 33-15-21 Acid Rain Program NDAC Chapter 33-15-22 E missions Standards for Hazardous Air Pollutants for Source Categories

It should be noted that unless specifically stated in the text, all references to existing rules or emission control programs are intended only to prov ide information about various aspects of the program described and are neither being submitted t o EPA for approval nor being incorporated into the SIP as Federally enforceable measures if t hey haven’t previous been incorporated.

This SIP is North Dakota’s comprehensive visibility plan which now contains both Phase 1 and Phase 2 visibility requirements. It addresses all a spects of North Dakota’s visibility improvement

program.

North Dakota is also setting emission limits as a p art of this SIP for those sources subject to Best Available Retrofit Technology (BART) requirements o f Phase 2 of the RHR which are described in detail in chapter 7 of this SIP.

This SIP documents those programs, rules, processes and controls deemed appropriate as measures to reduce regional haze and protect good v isibility in North Dakota toward meeting the 2018 and 2064 goals established in the EPA RHR and CAA.

EPA has several existing emission control programs /rules which do not specifically address visibility impairment that will control the emissio n of pollutants that cause or contribute to visibility impairment which will impact North Dakot a Class I areas. They include:13

CAIR. CAIR will permanently cap emissions of SO 2 and NO

x from EGUs in the eastern United States by 2015. When fully implemented, CAIR as ori ginally promulgated would have reduced

SO 2 emissions from EGUs in these states by more than 7 0%, and NO

x emissions by more than 60%, from 2003 levels. CAIR has been remanded with a replacement rule likely to take 2 years to finalize. Any emission reductions from a CAIR r eplacement rule are unknown at this time. When winds are from an easterly direction, North Da kota Class I areas will see some benefit

from the CAIR reductions.

NO

x SIP Call. Phase I of the NO

x SIP call applies to certain EGUs and large non-EGU s, including large industrial boilers and turbines, an d cement kilns in the eastern United States. It is expected to reduce NO

x emissions by 90% to mitigate ozone transport. Whe n winds are from an easterly direction, North Dakota Class I areas will see some benefit.

Heavy Duty Diesel (2007) Engine Standard (for on-ro ad trucks and buses). The EPA set a PM emissions standard for new heavy-duty engines of 0. 01 grams per brake-horsepower-hour(g/bhphr), to take full effect for diesel engines in the 2007 model year. This rule also includes standards

for NO

x and non-methane hydrocarbons (NMHC) of 0.20 g/bhp- hr and 0.14 g/bhp-hr, respectively. These NO

x and NMHC standards will be phased in together betw een 2007 and 2010, for diesel engines. Sulfur in diesel fuel mus t be lowered to enable modern pollution control technology to be effective on these trucks and buse s. The EPA will require a 97 percent reduction in the sulfur content of highway diesel f uel from its current level of 500 parts per million (low sulfur diesel, or LSD) to 15 parts per million (ultra-low sulfur diesel, or ULSD).

Tier 2 Tailpipe (On-road vehicles). The EPA mobile source rules include the Tier 2 fle et averaging program, modeled after the California LEV II standards. Manufacturers can produce vehicles with emissions ranging from relatively dir ty to zero emissions, but the mix of vehicles a manufacturer sells each year must have average NO

x emissions below a specified value. Tier 2 standards became effective in the 2005 model year.

Large Spark Ignition and Recreational Vehicle Rule . The EPA has adopted new standards for

emissions of NO

x , hydrocarbons, and carbon monoxide from several gr oups of previously unregulated nonroad engines. Included in these are large industrial spark-ignition engines and recreational vehicles. Nonroad spark-ignition engin es are those powered by gasoline, liquid propane gas, or compressed natural gas rated over 1 9 kilowatts (kW) (25 horsepower). These engines are used in commercial and industrial appli cations, including forklifts, electric generators, airport baggage transport vehicles, and a variety of farm and construction applications. Nonroad recreational vehicles include snowmobiles, off-highway motorcycles, and all-terrain-vehicles. These rules were initially ef fective in 2004 and will be fully phased-in by

2012.

Nonroad Diesel Rule . This rule sets standards that will reduce emissio ns by more than 90 percent from nonroad diesel equipment, and reduce sulfur le vels by 99 percent from current levels in nonroad diesel fuel starting in 2007. This step wil l apply to most nonroad diesel fuel in 2010 and

to fuel used in locomotives and marine vessels in 2 012.14

Industrial Boiler/Process Heater MACTs. The EPA issued final rules to substantially reduce emissions of toxic air pollutants from industrial, commercial and institutional boilers and process

heaters. These rules reduce emissions of a number o f toxic air pollutants, including hydrogen chloride, manganese, lead, arsenic and mercury by 2 009. This rule also reduces emissions of SO 2 and PM in conjunction with the toxic air pollutant reductions. The applied Maximum Achievable Control Technology (MACT) control efficiencies were 4 percent for SO 2 and 40 percent for

PM 10 and PM 2.5 . The EPA’s industrial boiler MACT rules were vacat ed on June 8, 2007, however it is believed that by 2018 the USEPA will have re-promulgated a boiler MACT rule; however, the emission reductions may change from th ose of the vacated rule.

Combustion Turbine and Reciprocating Internal Combu stion Engines MACTs . The EPA MACT regulations for Gas Turbines and stationary Recipro cating Internal Combustion will have NO

x co-benefit effects.

VOC 2-, 4-, 7-, and 10-year MACT Standards. Various point source MACTs and associated emission reductions have been implemented by EPA.



### 2.6 Reasonable Progress Toward the 2064 Visibility Goals

Section 51.308(d) contains the core requirements fo r the regional haze SIP. The requirements for reasonable progress goals (RPG) are found in 51.308 (d)(1) which reads:

“Reasonable progress goals. For each mandatory Clas s I Federal area located within the State, the State must establish goals (expressed in deciviews) that provide for reasonable progress towards achieving natural visibility condi tions. The reasonable progress goals must provide for an improvement in visibility for t he most impaired days over the period of the implementation plan and ensure no degradatio n in visibility for the least impaired days over the same period.”

The reasonable progress goals are interim goals tha t represent incremental visibility improvement over time for the most-impaired (20% wo rst) days and no degradation in visibility for the least-impaired (20% best) days. The first r egional haze plan that States must submit to EPA needs to include RPGs for the year 2018, also k nown as the “2018 milestone year”. The State has the flexibility in establishing different RPGs for each Class I area. In establishing the RPG, the State must consider four factors:

• the costs of compliance;

• the time necessary for compliance;

• the energy and non-air quality environmental impact s of compliance; and

• the remaining useful life of any potentially affect ed sources.

States must demonstrate how these factors were take n into consideration in selecting the RPG for

each Class I area.15

The North Dakota Department of Health has worked wi th the Western Regional Air Partnership (WRAP) and with the WRAP’s ongoing modeling program as well as implemented our own modeling program to establish and refine RPGs for 2 018 for the North Dakota Class I areas. This process is described in detail in sections 8 and 9.

The RPGs for each North Dakota Class I area establi shed for 2018 are found in section 9. Required BART controls will be installed and become operational as expeditiously as practicable, but no later than five years after thi s SIP is approved by EPA. The controls are expected to be operational in 2013 - 2014.

The technical analyses described in this SIP demons trate that emissions both inside and outside of North Dakota have an appreciable impact on the S tate’s Class I areas. This includes emissions from neighboring states as well as international em issions from Canada, especially from the provinces of Alberta and Saskatchewan. Emission con trols from many sources outside of North Dakota will not be fully defined during this round of the Regional Haze SIP process, necessitating consideration of outside controls and further interstate and possibly tribal consultation in the reasonable progress process to establish refined reasonable progress goals. The EPA, through the Department of State, will have to work with Canada and its provinces to reduce visibility impairing pollutants that impact North Dakota and other states’ Class I areas. Until SIP controls including BART and other program s outside of North Dakota are defined, modeled and analyzed, North Dakota cannot fully det ermine progress toward the 2018 goal or the 2064 goal. North Dakota will make its best att empt at demonstrating progress toward the goals based on addressing sources within its contro l.16



## 3. Plan Development and Consultation

The State is required by Section 51.308(d) (3) (i) of the EPA Regional Haze Rule to consult with other states to develop coordinated emission manage ment strategies for Class I areas in those states North Dakota’s emissions impact or those sta tes whose emissions impact North Dakota’s Class I areas and by Section 51.308(i) to consult w ith the federal land managers of the Class I

areas in our state and the Class I areas in other s tates that emissions from North Dakota impact.



### 3.1 Consultation with Federal Land Managers

The North Dakota Department of Health consults with the FLMs as a part of the WRAP and as needed directly with the National Park Service and U.S. Fish and Wildlife Service in Denver, CO. They have reviewed and commented on North Dako ta’s BART modeling protocol and draft BART determinations submitted by the BART sources.

The National Park Service, the U.S. Fish and Wildli fe Service, and the U.S. Forest Service (federal land manager of Boundary Waters Canoe Area Wilderness in Minnesota) were each furnished copies of the draft SIP for review and co mment as part of the required 60 day FLM comment period (Section 51.308(i)(2)). Continuin g consultation with the three FLM’s in the future as required by 40 CFR 51,308(i)(4) is addres sed in Section 11.1.1.



### 3.1.1 FLM Comments Provided During 60 Day Comment P eriod

A draft was provided to the FLMs in August 2009 for their 60-day consultation period. The FLM comments are included in Appendix J.



### 3.1.2 Response to FLM Comments

The Department’s responses to the FLM’s comments ar e included in Appendix J.



### 3.1.3 FLM Comments Provided on BART Portion of SIP in 2008

The Department had originally planned to submit the BART portion of the regional haze SIP separately from the Reasonable Progress portion of the SIP. The BART portion (which is now Section 7) was submitted to the FLMs in June of 200 8 as part of the required 60-day FLM comment period.

Comments that were received from the FLMs in August of 2008 are attached in Appendix J.1.1 and discussed further in Section 7. They have been reviewed and considered by the Department and included as appropriate in Section 7 of this cu rrent SIP. The Department’s responses to the FLM comments are attached in Appendix J.1.2.17



### 3.2 Consultation with EPA Region 8

The North Dakota Department of Health has consulted with EPA as a part of the WRAP and as needed directly with Air Program staff of the EPA R egion 8 office in Denver, CO in developing

this SIP. EPA has reviewed and commented on the Sta te BART modeling protocol, the BART Air Pollution Control Permit to Construct template and the draft BART determinations submitted by the BART sources.

In June of 2008, the Department submitted the BART portion of the SIP to EPA Region 8 at the

same time it was submitted to the FLMs as discussed in Section 3.1.3. Comments were received from EPA and are attached as Appendix J.3.1. The D epartment’s responses to the EPA comments are attached as Appendix J.3.2.

EPA was also provided a copy for comment of the dra ft SIP at the time it was provided to the FLMs as a part of the FLM 60 day comment period. T he Department considered the EPA comments and made appropriate revisions to the SIP.

The Department also consulted with EPA Region 8 con cerning Class I areas in Montana as they are preparing a federal implementation plan for Mon tana.



### 3.3 Consultation with Other States

The North Dakota Department of Health has consulted with our neighboring states of South Dakota and Montana through the WRAP and as needed i ndividually. We also participated in monthly teleconferences from 2004 through 2008 with Minnesota and Michigan, the states containing the four northern Class I areas (Boundar y Waters Canoe Wilderness Area and Voyageurs National Park in Minnesota, Isle Royale N ational Park and Seney National Wildlife Refuge Wilderness Area in Michigan), and other stat es in CENRAP and LADCO. We also individually consulted as needed with Minnesota, ou r neighbor directly to the east.

As a result of the consultations, Minnesota sent a memorandum dated September 19, 2007 to North Dakota and other states impacting Minnesota’s Class I areas. Minnesota requested a response documenting these consultations have taken place to the satisfaction of North Dakota or detailing areas where additional consultation shoul d occur. In those states Minnesota has identified as additional contribution states, they asked those states to respond with their agreement or disagreement with Minnesota’s determin ation of contributing states and the additional control strategies that will be evaluate d. Minnesota’s memorandum and the NDDoH letter of response dated August 22, 2008 are attach ed in Appendix J.2.

These states were notified of the availability of t he draft SIP at the time it was sent to the FLMs.18



### 3.4 Regional Planning Consultation

The North Dakota Department of Health became a memb er of the Western Regional Air Partnership (WRAP) in March of 1999. WRAP is one of five regional planning organizations representing 13 western states, tribes in those sta tes, federal agencies including EPA and FLMs, environmental organizations, industry, academics, a nd other stakeholders. Department staff has participated and continues to participate in many W RAP committees and workgroups including the Air Managers Committee, the Initiatives Oversig ht Committee, the Technical Oversight Committee, the Emissions Forum, the Stationary Sour ces Joint Forum, the Technical Analysis Forum, the Implementation Workgroup, and the BART W orkgroup. Membership in the WRAP and participation in its many committees, forums an d workgroups allows consultation with the many organizations WRAP represents.



### 3.5 Consultation with Tribes

The Department notified the tribes in North Dakota of the public hearing and comment period on the draft RH SIP. The Department also notified the WRAP Tribal Caucus Coordinator of its intent to draft a SIP to address regional haze and provided a list of contacts within the Department (see Appendix J.4).



### 3.6 Other Consultation

The Department has monthly teleconferences with the Subject-to-BART sources in North Dakota and has quarterly meetings with the Lignite Energy Council, an organization representing lignite coal mines and users within the State.19



## 4. Monitoring Strategy and Other Implementation Pla n Requirements

Part 40 CFR 51.305 and 51.308(d)(4) of the Federal Regional Haze Rule requires states to have a monitoring strategy in the SIP for addressing reaso nably attributable visibility impairment (RAVI) and regional haze visibility impairment in t he federal Class I areas within the State. The monitoring strategy required by 40 CFR 51.305 is di scussed in Section 4.1. The monitoring strategy required by 40 CFR 51.308(d)(4) is summari zed in Section 4.2 and is made a part of this

RH SIP.



### 4.1 RAVI Monitoring Strategy in Current North Dakota Lo ng Term Strategy

The RAVI monitoring strategy required by 40 CFR 51. 305 was first included in the long term strategy section of North Dakota’s first visibility protection SIP dated October 1, 1987 as Section 6.10. The visibility monitoring strategy was replac ed on March 1, 1994 with Section 6.12. It was again replaced on January 1, 1996 with Section 6.13 of the SIP which is the present RAVI monitoring strategy. Section 6.13 is:

Air Quality Surveillance

In April 1994, Section 6.12 of the SIP was submitte d to EPA indicating visibility monitoring was not necessary due to a lack of visib ility impairment and a database indicating stable conditions. In late 1994 and earl y 1995, there has been a resurgence of activity in the oil fields of Western North Dakota. The purpose of Section 6.13 is to withdraw Section 6.12 and identify current activiti es regarding visibility monitoring.

An increase in oil drilling activities in 1995 has prompted the Park Service to revisit the idea of establishing visibility monitoring sites at the Class I areas in North Dakota. The Department has met with the Park Service to discuss arrangements for financing visibility monitoring. The Department has offered to use funds from an environmental trust that was established through deposits from penalties col lected on several enforcement cases. Theodore Roosevelt National Park (TRNP) Service off icials were receptive and have transmitted requests to their offices in Denver. Pl ans currently call for the Department

and the Park Service to enter into a memorandum of understanding to proceed with establishing visibility monitoring at TRNP.

The Federal Land Managers installed IMPROVE monitor s in Theodore Roosevelt National Park South Unit and Lostwood National Wildlife Refuge Wi lderness Area in December of 1999.

The Department also worked with the National Park S ervice to install a webcam at the South Unit of TRNP using funds from the environmental tru st as included in Section 6.13. The webcam became operational in August of 2002. It can be acc essed on the internet at:20

http://www.nature.nps.gov/air/WebCams/parks/throcam /throcam.cfm . In addition to the webcam picture, current conditions for ozone, sulfur dioxi de, fine particulate matter (PM 2.5 ) and weather

have been added and can be observed.



### 4.2 Regional Haze Visibility Impairment Monitoring Strategy and Other Implementation Plan Requirements

Section 51.308(d)(4) requires that the State must s ubmit with the implementation plan a monitoring strategy for measuring, characterizing, and reporting of regional haze visibility impairment that is representative of all mandatory Class I Federal areas within the State. This monitoring strategy must be coordinated with the mo nitoring strategy required in section 51.305 for reasonably attributable visibility impairment. Compliance with this requirement may be met through participation in the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. The IMPROVE monitoring program is discussed in section 4.3.

The state of North Dakota will depend on the Intera gency Monitoring of PROtected Visual Environments (IMPROVE) monitoring program to collec t and report aerosol monitoring data for long-term reasonable progress tracking as specified in the Regional Haze Rule (RHR). Because the RHR is a long-term tracking program with an imp lementation period nominally set for 60 years, the state expects that the IMPROVE program w ill provide data based on the following goals:

1. Maintain a stable configuration of the individua l monitors and sampling sites, and stability in network operations for the purpose of continuity in tracking reasonable progress trends; 2. Assure sufficient data capture at each site of a ll visibility-impairing species; 3. Comply with EPA quality control and assurance re quirements; and 4. Prepare and disseminate periodic reports on IMPR OVE program operations.

The state of North Dakota is relying on the IMPROVE program to meet these monitoring operation and data collection goals, with the funda mental assumption that network data collection operations will not change, or if change d, will remain directly comparable to those operated by the IMPROVE program during the 2000-200 4 RHR baseline period. Technical analyses and reasonable progress goals in this impl ementation plan for Regional Haze are based on data from these sites. As such, the State asks that the IMPROVE program identify potential issues affecting RHR implementation trends and/or n otify the State before changes in the IMPROVE program affecting a RHR tracking site are m ade.

Further, the state of North Dakota notes that the h uman resources to operate these monitors are provided by Federal Land Management agencies. Beyo nd that in-kind contribution, resources for operation and sample analysis of a complete and representative monitoring network of these long-term reasonable progress tracking sites by the IMPROVE program are a collaborative responsibility of the EPA, states, tribes, and FLMs and the IMPROVE program steering

committee. The state of North Dakota will collabor ate with the EPA, FLMs, other states, tribes,21

and the IMPROVE committee to assure adequate and re presentative data collection and reporting by the IMPROVE program. North Dakota will consult with the FLMs if IMPROVE monitoring budget changes will threaten Class I area monitorin g within North Dakota, or in Class I areas affected by emissions from North Dakota.

Section 51.308(d)(4)(i) requires that the implement ation plan must also provide for the following:

(i) The establishment of any additional monitoring site s or equipment needed to assess whether reasonable progress goals to address region al haze for all mandatory Class I Federal areas within the State are being achieved

.

The state of North Dakota depends on the following IMPROVE program-operated monitors listed in Table 4.1 for tracking RHR reasonable pro gress.

Table 4.1 IMPROVE Monitoring Sites in North Dakota

IMPROVE Monitoring Site Class I Area Sponsor Start Date Elevation

MSL

LOST1 Lostwood National

Wilderness Area US Fish and

Wildlife Service 12/1999 696 m

2283 ft

THRO1 Theodore Roosevelt

National Park-South Unit, North Unit,

Elkhorn Ranch Unit National Park

Service 12/1999 862 m

2828 ft

Note that the THRO1 IMPROVE monitor is located at t he Painted Canyon Overlook in the

South Unit of Theodore Roosevelt National Park. The THRO1 IMPROVE monitor also serves and is representative of haze conditions in the sep arate North Unit and the separate Elkhorn

Ranch Unit of the Park. The monitor was sited at t he existing monitoring site at the Painted Canyon Overlook in December 1999 by the federal age ncies running the IMPROVE program. Site selection followed criteria in the Improve Par ticulate Monitoring Network Procedures for Site Selection, February 24, 1999, to be representa tive of the Park’s three units. The existing site at the Painted Canyon Overlook met all the siting c riteria including that all areas represented by the site should be within 100 km of a current or po tential site. The northern boundary of the North Unit is approximately 80 km away from the sit e and the Elkhorn Ranch Unit is approximately 45 km away.

The state of North Dakota will also operate additio nal non-IMPROVE monitors that may be used

in the future evaluations of Class I area visibilit y. These may include PM 2.5 speciation or Federal Reference Methods, monitoring systems for SO 2 , NO

x , ozone, continuous PM 2.5 , continuous

PM 10 , and meteorological monitors for wind speed, wind direction, ambient temperature, ambient pressure, relative humidity, solar radiatio n, and precipitation. Monitors presently operating are listed in Table 4.2.22 Table 4.2

Additional non-IMPROVE Monitors

Monitoring Site Parameter Sampling &Analysis

Method Operating

Schedule
Lostwood National Wildlife Refuge AQS#: 38-013-0004

Co-located with the LOST1 IMPROVE

site. Sulfur Dioxide Instrumental Pulsed Florescent Continuous Nitrogen Dioxide Instrumental Chemiluminescence Continuous

Ozone Instrumental Ultra Violet Continuous

PM 2.5 PM 2.5 SCC W/No Correction

TEOM Gravimetric 40 0 Celsius Continuous

PM 10 PM 10 TEOM Gravimetric 50 0

Celsius Continuous

Wind Speed Elec. or Mach Avg. Level 1 Continuous Wind Direction Elec. or Mach Avg. Level 1 Continuous

Ambient Temperature Elec. or Mach Avg. Continuous

Delta Temperature Elec. or Mach Avg. Continuous

Ambient

Pressure Barometric Pressure Transducer Continuous

Solar Radiation Pyranometer Continuous

Relative Humidity Hydgroscopic Plastic Film Continuous

Theodore Roosevelt National Park

North Unit AQS# 38-053-0002 Sulfur

Dioxide Instrumental Pulsed Florescent Continuous

Nitrogen Dioxide Instrumental Chemiluminescence Continuous

Ozone Instrumental Ultra Violet Continuous

PM 2.5 PM 2.5 SCC W/No Correction

TEOM Gravimetric 40 0 Celsius Continuous

PM 10 PM 10 TEOM Gravimetric 50 0

Celsius Continuous

Wind Speed Elec. or Mach Avg. Level 1 Continuous Wind Direction Elec. or Mach Avg. Level 1 Continuous

Ambient Temperature Elec. or Mach Avg. Continuous

Ambient

Pressure Barometric Pressure Transducer Continuous

Relative Humidity Hydroscopic Plastic Film Continuous

Theodore Roosevelt National Park

South Unit

Co-located with the THRO1 IMPROVE

Site. Sulfur

Dioxide

Instrumental Pulsed Florescent Continuous

Ozone Instrumental Ultra Violet Continuous

PM 2.5 PM 2.5 SCC W/ No Correction

TEOM Gravimetric 50 0 Celsius Continuous

Wind Speed Elec. or Mach Avg. Level 1 Continuous Wind Direction Elec. or Mach Avg. Level 1 Continuous

Ambient Temperature Elec. or Mach Avg. Continuous

Relative Humidity Hydroscopic Plastic Film Continuous

Solar Radiation Pyranometer Continuous Precipitation Recording Weighting Continuous23

It should be noted that the two IMPROVE monitors lo cated at the Theodore Roosevelt National

Park South Unit and the Lostwood National Wildernes s Area have complete data for the period 2000 through 2004 and are relied upon in this Regio nal Haze SIP to establish the baseline

deciview conditions.

In addition, the National Park Service monitors dry deposition at the Theodore Roosevelt National Park South Unit monitoring site. The dry d eposition is analyzed for SO 4 , NO 3 , HNO 3 , NH 4 , and SO 2 weekly.

Section 51.308(d)(4)(ii) requires that the implemen tation plan must also provide for the following:

(ii) Procedures by which monitoring data and other information are used in determining the contribution of emissions from with in the State to regional haze visibility impairment at mandatory Class I Federal areas both within and outside

the State.

The state of North Dakota will use data reported by the IMPROVE program as part of the regional technical support analysis tools found at the Visibility Information Exchange Web System (VIEWS), as well as other analysis tools tha t are available from EPA, FLMs and other

states and tribes. The state of North Dakota will participate in any ongoing regional analysis activities to collectively assess and verify the pr ogress toward reasonable progress goals, also supporting interstate consultation as the RHR is im plemented, and collaborate with EPA, states, tribes, and FLMs to ensure the continued operatio n of existing technical support analysis tools and systems developed by WRAP. If the WRAP systems disappear, North Dakota will develop or contract for other technical support analysis to ols and systems as necessary.

The state of North Dakota may conduct additional an alyses as needed.

Section 51.308(d)(4)(iv) requires that the implemen tation plan must also provide for the following:

(iv) The implementation plan must provide for th e reporting of all visibility monitoring data to the Administrator at least annually for eac h mandatory Class I Federal area in the State. To the extent possible, the State sho uld report visibility monitoring data electronically.

The state of North Dakota will depend on the routin e timely reporting of haze monitoring data by the IMPROVE program for the reasonable progress tra cking sites to the EPA air quality data system and VIEWS. The state of North Dakota will c ollaborate with EPA, states, tribes, and FLMs to ensure the continued operation of existing WRAP technical support analysis tools and

systems.

The additional non-IMPROVE monitoring is conducted and the data collected and reported in accordance with EPA guidance. It is reported throug h electronic data transfer techniques quarterly.24

Section 51.308(d)(4)(v) requires that the implement ation plan must also provide for the following:

(v) A statewide inventory of emissions of pollutant s that are reasonably anticipated to cause or contribute to visibility impairment in any mandatory Class I Federal area. The inventory must include emissions for a baseline year, emissions for the most recent year for which data are available, and estim ates of future projected

emissions. The State must also include a commitment to update the inventory periodically.

The state of North Dakota has prepared a statewide inventory of emissions that can reasonably be expected to cause or contribute to visibility im pairment in Federal Class I Areas. Section 6 of this plan summarizes the emissions by pollutant and source category.

The state of North Dakota commits to updating state wide emissions inventories periodically and submitting data to the EPA NEI system. The updates will be used for state tracking of emission changes, trends, and evaluation of whether reasonab le progress goals are being achieved and other regional analyses. The inventories will be up dated every one to three years on the same schedule as the every three-year reporting required by EPA’s Consolidated Emissions Reporting Rule and the Air Emissions Reporting Requirements R ule. The Air Emissions Reporting Requirements Rule will completely replace the Conso lidated Emissions Reporting Rule after the 2008 emission inventory data submittal which is due to June 1, 2010.

As a member of the WRAP, North Dakota will continue to use the WRAP-sponsored Emissions Data Management System (EDMS) and Fire Emissions Tr acking System (FETS) to store and access emission inventory data for the region as lo ng as they are maintained and available. If they are not available, North Dakota stores its dat a in house. North Dakota will continue to conduct its own modeling to simulate the air qualit y impacts of emissions for haze and other related air quality planning purposes. The state of North Dakota will collaborate with EPA, states, tribes and FLMs to ensure the continued ope ration of existing WRAP technical support analysis tools and systems.

Section 51.308(d)(4)(vi) requires that the implemen tation plan must also provide for the following:

(vi) Other elements, including reporting, recordkee ping, and other measures, necessary to assess and report on visibility.

The state of North Dakota will track data related t o RHR haze plan implementation for sources for which the state has regulatory authority, and w ill depend on the IMPROVE program for monitoring data. To ensure the availability of dat a and analyses to report on visibility conditions and progress toward Class I area visibility goals, the state of North Dakota will collaborate with EPA, states, tribes and FLMs to ensure the continue d operation of the IMPROVE program and the existing WRAP-sponsored technical support analy sis tools and systems for emissions inventory data.

### 4.3 Overview of the IMPROVE Monitoring Network

In the mid program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal cooperative relationship between the EPA, Na Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western States Air Resources Council (WES (MARAMA) and Northeast States for Coordinated Air U se Management (NESCAUM).

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol conditions in mandatory Class sources responsible for existing human trends for assessing progress towards the national visibility goals; and supporting the requirements of visibility Lostwood National Wilderness Area, and Figure 4.2 s hows the four separate module sampling the different pollutant species. 

### Overview of the IMPROVE Monitoring Network

In the mid -1980’ s, the Interagency Monitoring of PROtected Visual program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal cooperative relationship between the EPA, Na Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western States Air Resources Council (WES (MARAMA) and Northeast States for Coordinated Air U se Management (NESCAUM).

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol conditions in mandatory Class sources responsible for existing human trends for assessing progress towards the national visibility goals; and supporting the requirements of the Regional Haze Rule by providing regional haze m onitoring representing all visibility

- protected Federal Class I areas where practical. Fi gure 4.1 shows the IMPROVE site at Lostwood National Wilderness Area, and Figure 4.2 s hows the four separate module sampling the different pollutant species. 

### Overview of the IMPROVE Monitoring Network

s, the Interagency Monitoring of PROtected Visual program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal cooperative relationship between the EPA, Na Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western States Air Resources Council (WES (MARAMA) and Northeast States for Coordinated Air U se Management (NESCAUM).

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol conditions in mandatory Class I Federal areas; identifying the chemical species a nd emission sources responsible for existing human trends for assessing progress towards the national visibility goals; and supporting the

the Regional Haze Rule by providing regional haze m onitoring representing all protected Federal Class I areas where practical. Fi gure 4.1 shows the IMPROVE site at Lostwood National Wilderness Area, and Figure 4.2 s hows the four separate module sampling the different pollutant species.



### Pictures of the

Lostwood National Wilderness Area 

### Overview of the IMPROVE Monitoring Network

s, the Interagency Monitoring of PROtected Visual program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal cooperative relationship between the EPA, Na Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western States Air Resources Council (WES TAR), Mid (MARAMA) and Northeast States for Coordinated Air U se Management (NESCAUM).

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol I Federal areas; identifying the chemical species a nd emission sources responsible for existing human

- made visibility impairment; documenting long trends for assessing progress towards the national visibility goals; and supporting the

the Regional Haze Rule by providing regional haze m onitoring representing all protected Federal Class I areas where practical. Fi gure 4.1 shows the IMPROVE site at Lostwood National Wilderness Area, and Figure 4.2 s hows the four separate module sampling the different pollutant species.



### Pictures of the IMPROVE Monitoring Site

Lostwood National Wilderness Area

25 

### Overview of the IMPROVE Monitoring Network

s, the Interagency Monitoring of PROtected Visual program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal cooperative relationship between the EPA, Na tional Park Service, U.S. Fish and Wildlife Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western TAR), Mid

- Atlantic Regional Air Management Association (MARAMA) and Northeast States for Coordinated Air U se Management (NESCAUM).

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol I Federal areas; identifying the chemical species a nd emission

made visibility impairment; documenting long trends for assessing progress towards the national visibility goals; and supporting the

the Regional Haze Rule by providing regional haze m onitoring representing all protected Federal Class I areas where practical. Fi gure 4.1 shows the IMPROVE site at Lostwood National Wilderness Area, and Figure 4.2 s hows the four separate module



### Figure 4.1 IMPROVE Monitoring Site

Lostwood National Wilderness Area

Exterior 

### Overview of the IMPROVE Monitoring Network

s, the Interagency Monitoring of PROtected Visual program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal tional Park Service, U.S. Fish and Wildlife Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western Atlantic Regional Air Management Association (MARAMA) and Northeast States for Coordinated Air U se Management (NESCAUM).

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol I Federal areas; identifying the chemical species a nd emission

made visibility impairment; documenting long trends for assessing progress towards the national visibility goals; and supporting the

the Regional Haze Rule by providing regional haze m onitoring representing all protected Federal Class I areas where practical. Fi gure 4.1 shows the IMPROVE site at Lostwood National Wilderness Area, and Figure 4.2 s hows the four separate module



### Figure 4.1 IMPROVE Monitoring Site

Lostwood National Wilderness Area

Exterior 

### Overview of the IMPROVE Monitoring Network

s, the Interagency Monitoring of PROtected Visual Environments (IMPROVE) program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal tional Park Service, U.S. Fish and Wildlife Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western Atlantic Regional Air Management Association (MARAMA) and Northeast States for Coordinated Air U se Management (NESCAUM).

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol I Federal areas; identifying the chemical species a nd emission

made visibility impairment; documenting long trends for assessing progress towards the national visibility goals; and supporting the

the Regional Haze Rule by providing regional haze m onitoring representing all protected Federal Class I areas where practical. Fi gure 4.1 shows the IMPROVE site at Lostwood National Wilderness Area, and Figure 4.2 s hows the four separate module



### IMPROVE Monitoring Site at
Lostwood National Wilderness Area Environments (IMPROVE) program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal tional Park Service, U.S. Fish and Wildlife Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western Atlantic Regional Air Management Association (MARAMA) and Northeast States for Coordinated Air U se Management (NESCAUM).

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol I Federal areas; identifying the chemical species a nd emission

made visibility impairment; documenting long

trends for assessing progress towards the national visibility goals; and supporting the

the Regional Haze Rule by providing regional haze m onitoring representing all protected Federal Class I areas where practical. Fi gure 4.1 shows the IMPROVE site at Lostwood National Wilderness Area, and Figure 4.2 s hows the four separate module s used for



### at Environments (IMPROVE) program was established to measure visibility impai rment in mandatory Class I Federal areas throughout the United States. The monitoring sites are operated and maintained through a formal tional Park Service, U.S. Fish and Wildlife Service, Bureau of Land Management, NOAA and U.S. F orest Service. In 1991, several additional organizations joined the effort: Nationa l Association of Clean Air Agencies, Western Atlantic Regional Air Management Association

The objectives of the IMPROVE program include estab lishing the current visibility and aerosol I Federal areas; identifying the chemical species a nd emission

- term trends for assessing progress towards the national visibility goals; and supporting the

the Regional Haze Rule by providing regional haze m onitoring representing all protected Federal Class I areas where practical. Fi gure 4.1 shows the IMPROVE site at

s used for



### at26 

### Interior27

The IMPROVE sampler consists of four separate modul es for measuring regional haze



### Figure 4.2 IMPROVE Sampler Module

The data collected at the IMPROVE monitoring sites are used by land managers, industry planners, scientists, public interest groups and ai r quality regulators to better understand and protect the visual air quality resource in Class I areas. Most importantly, the IMPROVE Program scientifically documents the visual air quality of the wilderness areas and national parks.

The IMPROVE program has developed methods for estim ating light extinction from speciated aerosol and relative humidity data. The three most common metrics used to describe visibility impairment are:

Extinction (b ext ) – Extinction is a measure of the fraction of light lost per unit length along a sight path due to scattering and absorption by gases and particles, expressed in inverse Megameters (Mm -1 ). This metric is useful for representing the contr ibution of each aerosol species to visibility impairment and c an be practically thought of as the units of light lost in a million meter distance.

Visual Range (VR) – Visual range is the greatest distance a large bla ck object can be seen on the horizon, expressed in kilometers (km) o r miles (mi).28

Deciview (dv) – This is the metric used for tracking regional haz e in the RHR. The deciview index was designed to be linear with respe ct to human perception of visibility. A one deciview change is approximately equivalent t o a 10% change in extinction, whether visibility is good or poor. A one deciview change in visibility is generally considered to be the minimum change the average per son can detect with the naked eye.

See Section 5.1 for additional information.

For reference, Figure 4.3 compares b ext in Mm -1 , deciviews (dv) which are unitless, and visual range in kilometers (km).

Figure 4.3

Comparison of Extinction (Mm -1 ), Deciview (dv), and Visual Range (km)

The IMPROVE network estimates light extinction base d upon the measured mass of various contributing aerosol species. EPA’s 2003 guidance f or calculating light extinction is based on the original protocol defined by the IMPROVE program in 1988. For further information, see: http://vista.cira.colostate.edu/improve/Publication s/GuidanceDocs/guidancedocs.htm

.

In December 2005, the IMPROVE Steering Committee vo ted to adopt a revised algorithm for use by IMPROVE as an alternative to the original ap proach.

The choice between use of the default or the revise d equation for calculating the visibility metrics for each Class I area is made by the state in which the Class I area is located. North Dakota has chosen to use the revised equation. The revised algorithm for estimating light extinction is calculated as recommended for use by the IMPROVE steering committee using the following equations:

b ext ≈ 2.2×f

s (RH)×[Small Amm. Sulfate] + 4.8×f L (RH)×[Large Amm. Sulfate]

+2.4×f

s (RH) × [Small Amm. Nitrate] + 5.1×f L (RH) × [Large Amm. Nitrate] +2.8× [Small Particulate Organic Matter] + 6.1× [La rge Particulate Organic
Matter] +10× [Elemental Carbon] +1× [Fine Soil]

+1.7×f

ss (RH) × [Sea Salt] +0.6× [Coarse Mass] +0.33× [NO 2 (ppb)] +Rayleigh Scattering (Site Specific)29

Where:

b ext

= light extinction in units of inverse megameters (Mm -1 ),

f

S (RH) = function of relative humidity for small size fraction,

f

L (RH) = function of relative humidity for large size fraction,

f

SS (RH) = function of relative humidity for sea salt, and all species concentrations are provided in μg/m 3

.

The revised algorithm splits ammonium sulfate ((NH 4 ) 2 SO 4 ), ammonium nitrate (NH 4 NO 3 ) and total particulate organic matter (POM =1.8 × organi c carbon) concentrations into small and large size fractions. The equations for ammonium sulfate are:

[Large (NH 4 ) 2 SO 4 ] = [ Total (NH 4 ) 2 SO 4 ] 2 ÷ 20, for [Total (NH 4 ) 2 SO 4 ] < 20 μg/m 3
[Large (NH 4 ) 2 SO 4 ] = [Total (NH 4 ) 2 SO 4 ], for [Total (NH 4 ) 2 SO 4 ] ≥ 20μg/m 3

[Small (NH 4 ) 2 SO 4 ] = [Total (NH 4 ) 2 SO 4 ] – [Large (NH 4 ) 2 SO 4 ]

Similar equations are used to apportion total ammon ium nitrate and total particulate organic matter concentrations into small and large size fra ctions.

Light extinction is converted to deciview using the following relationship:

dv = 10 × ln(b ext

/10)

Where: dv = deciview,

b ext

= light extinction in units of inverse megameters (Mm -1 ).30



## 5. Baseline and Natural Visibility Conditions and U niform Rate of Progress for North Dakota Class I Areas

5.1 The Deciview

The Clean Air Act (Section 169A(a)(1)) states “Cong ress hereby declares as a national goal the prevention of any future, and remedying of any exis ting impairment of visibility in mandatory Class I Federal areas which impairment results from man-made air pollution.” In order to achieve this goal, all man-made pollution must be e liminated such that natural conditions (visibility) are restored. Natural conditions incl ude naturally occurring phenomena that reduce visibility as measured in terms of light extinction , visual range, contrast, or coloration (40 CFR 51.301). The State is required to develop a SIP th at contains measures that make reasonable progress toward the national goal of no man-made vi sibility impairment.

The primary metric for assessing baseline condition s, natural conditions and the rate of progress

is the deciview. A deciview is a haze index derive d from calculated light extinction, such that uniform changes in haziness correspond to uniform i ncremental changes in perception across the entire range of conditions, from pristine to highly impaired. The deciview index is calculated based on the following equation:

Deciview haze index = 10 ln (b ext /10 Mm -1 )

Where: b ext

= the atmospheric light extinction coefficient exp ressed in inverse megameters (Mm -1 )

The deciview scale is zero for pristine conditions and increases as visibility degrades. Each one deciview change represents a perceptible or small j ust-noticeable change in visual air quality or haziness to the average person under most circumsta nces when viewing scenes in Class I areas regardless of background visibility conditions. Th is is approximately a 10% change in the light extinction (Mm -1 ) reading.

In order to determine the rate of progress of visib ility improvement, the baseline conditions and

natural conditions must be determined for each Clas s I area. The baseline visibility conditions are calculated from IMPROVE data for the years 2000 -2004. Natural visibility conditions are determined by estimating the natural concentrations of visibility impairing pollutants that existed prior to man’s influence. These concentrations are then used to calculate light extinction and the

deciview metric.



### 5.2 Baseline Visibility Conditions

The Class I Federal Areas in North Dakota are the N orth Unit, South Unit and Elkhorn Ranch

Unit of Theodore Roosevelt National Park and the Lo stwood Wilderness Area. Although IMPROVE monitoring data is not available for the No rth Unit and Elkhorn Ranch Units of31

TRNP, the Department considers monitoring data from the South Unit to be representative of

conditions at the other two units. See Section 4.2 for a discussion of the representativeness of the

monitor in the South Unit for the other two units o f TRNP. Since the monitoring is representative, we only refer to the TRNP although there are three distinct separate areas.

Baseline visibility is the average of the IMPROVE m onitoring data for 2000 through 2004. Baseline visibility is calculated for both the 20 p ercent best and 20 percent worst days. The monitoring data from the IMPROVE sites as plotted b y WRAP and displayed on their TSS website are shown in Figures 5.1 - 5.4.

Figure 5.1

Figure 5.2

Figure 5.332 Figure 5.3

Figure 5.433

Based on the IMPROVE data, the baseline visibility conditions in the North Dakota Class I areas

are shown in Table 5.1.

Table 5.1 Baseline Visibility (Deciviews)

Year TRNP LWA

20% Best Days 20%

Worst Days 20%

Best Days 20%

Worst Days

2000 8.2 18.1 9.1 19.7

2001 7.8 18.0 8.2 20.6

2002 7.8 17.0 7.9 18.8

2003 7.5 18.4 7.9 18.6

2004 7.5 17.5 7.9 20.2 Baseline (avg.) 7.8 17.8 8.2 19.6

Note: Figures 5.1-5.4 and Table 5.1 are based on th e revised IMPROVE Algorithm. The source of the figures and data is the WRAP TSS website. A description of the WRAP methodology is found in Appendix A.5.



### 5.3 Natural Visibility Conditions

EPA has prepared “Guidance for Estimating Natural V isibility Conditions Under the Regional Haze Program” (EPA-454/B-03-005, Sept. 2003) to aid states in estimating natural visibility conditions. Natural visibility conditions represen t the long-term degree of visibility that is estimated to exist in a given Class I area in the a bsence of man-made impairment. Natural visibility conditions are not constant, but vary wi th changing natural processes such as fire, windblown dust, volcanic activity and biogenic emis sions. EPA has developed a default approach which will satisfy the requirements for th e initial SIP which addresses regional haze. The default approach defines two separate regions o f the United States (1) The East, which consists of all states east of the Mississippi Rive r, and up to one tier of states west of the Mississippi; and (2) the West, including the region s of the Mountain and Pacific time zones. States that are near the boundary between East and West are free to choose which set of natural visibility values are more appropriate and adopt th ose values. North Dakota is considered to be in the West Region; however, it is one of those sta tes that are on the boundary of East and West. Appendix B of EPA guidance document provides the de fault natural extinction values (deciviews) for both the best and worst days. The v alues for the North Dakota Class I areas are

shown in Table 5.2.34 Table 5.2 EPA Default Natural Visibility Conditions (Deciview s)

Area Best Days Worst Days

TRNP 2.19 7.31

LWA 2.21 7.33

These natural visibility condition values were calc ulated based on an IMPROVE algorithm which has since been modified. The new IMPROVE equ ation accounts for the effect of particle size distribution on light extinction efficiency of sulfate, nitrate and organic carbon. The mass multiplier for organic carbon is increased from 1.4 to 1.8. New terms were added to the equation to account for light extinction by sea salt and lig ht absorption by gaseous nitrogen dioxide. Site specific values are used for Rayleigh scattering to account for variations in elevation and temperature. Separate relative humidity enhancemen t factors are used for small and large size distributions of ammonium sulfate, ammonium nitrate and sea salt.

The WRAP calculated the natural background visibili ty conditions consistent with EPA’s guidance using the revised IMPROVE equation. The r esults of that calculation are shown in

Table 5.3.

Table 5.3

WRAP Calculated Natural Visibility Conditions (Deci views)

Area Best Days Worst Days

TRNP 3.0 7.8

LWA 2.9 8.0

The values in Table 5.3 have been established as th e natural background values for North Dakota and are used to establish the uniform rate of progr ess. The improvement necessary to achieve

natural conditions is shown in Table 5.4.35 Table 5.4 Improvement Necessary To Achieve Natural Conditions

(Deciviews)

Area Baseline

Best Days Natural

Best Days Improvement

Required Baseline

Worst Days Natural

Worst Days Improvement

Required

TRNP 7.8 3.0 4.8 17.8 7.8 10.0

LWA 8.2 2.9 5.3 19.6 8.0 11.6



### 5.4 Uniform Rate of Progress

The uniform rate of progress to achieve natural con ditions in any Class I Federal area is

calculated as the difference between baseline condi tion for the 20% worst days and natural condition for the 20% worst days divided by 60 year s (2004-2064). Mathematically it is determined by the following equation:

URP = [Baseline Condition - Natural Condition] ) 60 yrs dv/yr

By multiplying the uniform rate of progress by 14 y ears in the first planning period (10 years thereafter), the progress needed by 2018 to be on t he path to achieving natural conditions can be calculated as shown in Figure 5.5.

Figure 5.5

∆ dv = Baseline conditions minus natural conditions36

Based on the above data, the uniform rate of progre ss is calculated as follows:

Theodore Roosevelt National Park

URP = (17.8 – 7.8)(14/60) dv

URP = 2.3 dv

Lostwood Wilderness Area

URP = (19.6 – 8.0)(14/60) dv

URP = 2.7 dv

The uniform rate of progress for the Theodore Roose velt National Park and Lostwood Wilderness Area for the first planning period is sh own graphically in Figures 5.5 and 5.6. For the best days, the State must ensure that no degrad ation occurs over the same planning period.

Figure 5.637 Figure 5.738



## 6. Sources of Visibility Impairment in North Dakota Class I

Areas

6.1 Introduction

40 CFR 51.308(d)(4)(v) requires a statewide invento ry of emissions of pollutants that are reasonably anticipated to cause or contribute to vi sibility impairment in any mandatory Class I

Federal Area be included in the SIP. Emissions wit hin North Dakota are both naturally occurring and man-made. Naturally occurring emissi ons include wildfires, windblown dust and others. In North Dakota, the primary sources of an thropogenic emissions include electric utility steam generating units (EGUs), energy production an d processing sources, agricultural production and processing sources, prescribed burni ng and fugitive dust sources. The North Dakota inventory includes emissions of sulfur dioxi de (SO 2 ), nitrogen oxides (NO

x ), fine particulate matter (PMF), coarse particulate matter (PMC), organic carbon (OC), volatile organic compounds (VOC), elemental carbon (EC) and ammonia (NH 3 ).



### 6.2 Emissions in North Dakota

The most recent complete inventory of all emission categories is from 2002. The point source data was compiled by the State while the rest of th e inventory was prepared by the WRAP and its contractors with input from the state (Case Plan 02 d – see Section 9 for a discussion of this case plan). A summary of the inventory is shown in Tabl e 6.1. The WRAP Oil and Gas inventory for sulfur dioxide was adjusted to include sulfur dioxi de emissions from flaring and lease use of sour gas at well sites (WRAP did not include flaring and lease use emissions). The adjustment was based on hydrogen sulfide data for the combusted ga s, which is compiled by the Health Department, and the amount of gas flared or used on site which is compiled by the North Dakota

Oil and Gas Division.39Table 6.1North Dakota 2002 Emissions Inventory (tons)PointAll FireBiogenicAreaAreaO&GOnRoadMobileOffRoadMobileRoadDustFugitiveDustWindBlownDustTotalSO2157,06954005,5574,9588127,2463260176,211NOx87,4381,77444,56910,8334,63124,74655,5023400229,536OC2623,65701,46602311,0342011,98908,840EC29510026202723,6251513504,847PMF2,00282101,6170003,08636,35417,63961,519PMC56550301990141028,711172,066158,752360,936NH35188120118,398073233000120,493VOC2,0863,849233,56160,4557,74012,81413,515000334,020CO11,94460,73567,76921,93336211,84295,869000470,129Total261,91273,200345,898220,71917,365251,590176,82532,020210,610176,3911,766,52940

A complete emissions inventory is not available for a more recent year. However, more recent data for point source emissions are available for 2 007. Those data are shown in Table 6.2.

Table 6.2 North Dakota Point Source Emissions Inventory 2007

SO 2 NO

x OC EC PMF PMC NH 3 VOC CO

Point Sources 147,998 82,185 526 31 655 2,749 6,446 4,579 15,897

WRAP has developed a future inventory for North Dak ota for the year 2018. The PRP18b emissions inventory for North Dakota is shown in Ta ble 6.3. Again, sulfur dioxide emissions for the Area Oil and Gas inventory were increased by th e Department to include emissions from flaring and lease use of sour gas. The PRP18b emis sions inventory also included the proposed Gascoyne 500 coal-fired power plant. The Permit to Construct application for this facility has been withdrawn. The sulfur dioxide and nitrogen ox ides emissions for this plant were removed from the inventory by the Department. The Departme nt does not expect any additional coalfired power plants to be constructed in North Dakot a before 2018.

The Department does not agree with WRAP’s estimate of nitrogen oxides emissions from the Area Oil and Gas industry for 2018. WRAP has predi cted that 2018 NO

x emissions would be 4.5 times greater than 2002 emissions. The Departm ent discussed this estimate with the Oil and

Gas Division of the North Dakota Industrial Commiss ion. It was the opinion of the Oil and Gas Division that most of the Bakken formation developm ent will be over by 2018 and drilling rig activities are expected to settle back to the same ratio as production (i.e., 2-2.5 times the 2002 levels). Based on discussions with the Oil and Gas Division, it is believed that an increase of 2 – 2.5 times the 2002 emission rate is appropriate for 2018. In subsequent discussions with WRAP, representatives of WRAP admitted that 2018 estimate s of NO

x emissions related to oil and gas activity in North Dakota may have been overstated. The inventory in Table 6.3 represents a 2.5

times increase for Area Oil and Gas sources.

The Department also disagrees with WRAP’s estimate of PMF and PMC emissions for 2018. As explained in Section 9.5.2, agricultural conservati on tillage practices, which reduce emissions, are expected to increase by 2018. Since agricultur al activities and farm land are the major sources of fugitive and windblown PMF and PMC emiss ions, it is expected these emissions will decrease. Even though a decrease is expected, the emissions of PMF and PMC shown in Table 6.3 were not adjusted by the Department.

In future Regional Haze SIP reviews, the Department will use the most current, refined

emissions inventories available.41Table 6.3North Dakota 2018 Emission Inventory (tons)PointAll FireBiogenicAreaAreaO&GOnRoadMobileOffRoadMobileRoadDustFugitiveDustWindBlownDustTotalSO259,56033705,9954,20081276330070,482NOx62,3831,07344,56912,45611,5774,90634,5573410171,566OC2482,64701,38701514571932,04107,126EC3244902670481,3631413902,312PMF2,08640401,6470002,95637,99917,63962,731PMC2,34946002160111027,478184,063158,752373,429NH34623790118,49307394700120,120VOC2,4182,346233,56169,59717,9683,4878,357000337,735CO17,47741,60467,76921,47417290,152102,471000341,118Total147,01549,699345,898231,53233,91799,675147,52830,648224,314176,3911,486,61842

The change in emissions during the planning period (2002-2018) is shown in Table 6.4.

Table 6.4 North Dakota Emission Inventory Planning Period Cha nge

2002 (TPY) 2018

(TPY) Change

(TPY) Change

(%)

SO 2 176,211 70,482 -105,729 -60.0

NO

x 229,536 171,566 -57,970 -25.3

OC 8,840 7,126 -1,714 -19.4

EC 4,847 2,312 -2,535 -52.3

PMF 61,519 62,731 1,212 2.0

PMC 360,936 373,429 12,493 3.5

NH 3 120,493 120,120 -373 -0.3

VOC 334,020 337,735 3,715 1.1

CO 470,129 341,118 -129,011 -27.4



### 6.3 Emissions from Other States and Canadian Provin ces

The visibility in the Class I areas in North Dakota is influenced by emissions from surrounding states, Canada and sources outside WRAP’s modeling domain. The three contiguous states to North Dakota are Montana, South Dakota and Minnesot a. The 2002 emissions from the respective states are shown in Table 6.5.43 Table 6.5 Nearby States 2002 Emissions (tons)

Montana a South Dakota a Minnesota b North a

Dakota

SO 2 51,923 22,725 160,000 176,211

NO

x 243,142 146,822 485,000 229,536

OC 48,088 9,166 8,840

EC 11,873 4,703 4,847

PMF 77,239 82,414 169,000 61,519

PMC 621,276 615,354 610,000 360,936

NH 3 66,229 120,406 179,000 120,493

VOC 1,181,318 518,981 366,000 334,020

CO 1,639,949 509,702 470,129

a Source - WRAP TSS (Case Plan 02d)

b Source - Minnesota Draft Haze SIP

North Dakota’s contribution to visibility impairmen t in TRNP and LWA is generally small (see Table 6.6). Sulfates and nitrates, as discussed fu rther in Section 8, are the primary pollutants of

concern in these Class I areas. In-state sources c ontribute 21 percent or less of sulfate or nitrate during the 20 percent worst baseline days at TRNP o r LWA. It should be noted in Table 6.6 the sulfate and nitrate values are based on WRAP region al modeling using the CAM

x – PSAT source apportionment total, while the analyses of weighted emissions potential for organic carbon (OC), elemental carbon (EC), and particulate matter (PM) are based on emissions and residence time, not modeling.44 Table 6.6

ND Sources Extinction Contribution

2000-2004 20% Worst Days

Class I Area Pollutant

Species Extinction

(Mm -1 ) Species Contribution

To

Total Extinction (%) ND Sources

Contribution To Species Extinction (%) a

TRNP Sulfate

Nitrate

OC

EC

PMF

PMC

Sea Salt 17.53

13.74

10.82

2.75

0.9

4.82

0.07 35

27

21

5

2

10

0 21

19

12

29

44

45

0

LWA Sulfate

Nitrate

OC

EC

PMF

PMC

Sea Salt 21.4

22.94

11.05

2.84

0.62

3.93

0.26 34

36

18

5

1

6

0 18

13

23

35

28

32

0

a North Dakota contribution for sulfate and nitrate b ased on WRAP’s tracer analysis and OC, EC, PMF, PMC and Sea Salt contribution based on WRA P’s weighted emissions potential analysis.

In general, sources within Canada and sources outsi de WRAP’s modeling domain are bigger contributors to regional haze in TRNP and LWA than North Dakota sources.

The influence of sources outside of North Dakota on TRNP and LWA for the 2000-2004 period can be seen in Figures 6.1-6.16 and Table 6.7. The se figures and data were obtained from the WRAP TSS website. Figures 6.3, 6.4, 6.9 and 6.10 a re based on WRAP’s tracer analysis study which is considered a more rigorous analysis than t he weighted emissions potential analysis (Figures 6.5 – 6.8 and 6.11 – 6.16). The Departmen t does not agree with the WRAP’s estimate of nitrogen oxides emissions from the oil and gas s ource category for 2018 (see Section 6.2). The Department believes WRAP has overestimated the 2018 nitrogen oxides emissions. Therefore, Figures 6.4 and 6.12 overestimate the pe rcentage of oil and gas nitrogen oxides

contribution for 2018.Figure 6.1

Figure 6.2

45Figure 6.3

Figure 6.4

46Figure 6.

Figure 6.

47 5

6Figure 6.

Figure 6.

48 7

8Figure 6.

Figure 6.

49 9

10Figure 6.11

Figure 6.12

50Figure 6.

Figure 6.

51 13

14Figure 6.

Figure 6.

52 15

1653 Table 6.7 Source Region Apportionment 20% Worst Days

Contributing

Area Class I Area

TRNP LWA

SO 4 NO 3 SO 4 NO 3 North Dakota 21.1% 19.1% 17.9% 13.0%

Canada 28.3% 31.8% 45.9% 44.6%

Outside Domain 32.6% 17.9% 20.2% 14.0%

Montana 3.1% 15.0% 2.4% 9.3%

CENRAP 4.9% 2.5% 5.3% 5.1%

Other 10.5% 13.7% 8.3% 14.0%

The primary Canadian provinces which influence visi bility in the Class I areas of North Dakota are Saskatchewan, Alberta, Manitoba and British Col umbia. Emissions from these provinces in 2002, as reported in WRAP’s TSS website, totaled mo re than one million tons of sulfur dioxide, 1.4 million tons of nitrogen oxides and 2 million t ons of particulate matter as shown in Table 6.8.

Table 6.8 2002 Canadian Emissions (tons)

SO 2 NO

x PMC PMF
Saskatchewan 126,528 292,539 364,739 78,108
Manitoba 398,806 142,685 144,928 25,403
Alberta 433,394 752,966 503,835 807,738
British Columbia 101,990 214,914 64,545 39,695

The location of sulfur dioxide and nitrogen oxides emissions, as reported by Environment Canada, are shown in Figures 6.17 and 6.18. As can be seen, the heaviest concentration of emissions of sulfur dioxide and nitrogen oxides are northwest, in the prevailing wind direction of North Dakota’s Class I areas, especially the Lostwo od Wilderness Area.54 Figure 6.1755 Figure 6.18

Three major coal-fired electric utility steam gener ating plants within Saskatchewan are located just north of the U.S./Canada border within 250 km of the Lostwood Wilderness Area. During 2002, emissions from these plants totaled nearly 11 0,000 tons of sulfur dioxide and 38,000 tons of nitrogen oxides as shown in Table 6.9. The Boun dary Dam plant, which has the largest amount of emissions, is located within 60 kilometer s of LWA.

Table 6.9 Saskatchewan Power Plants 2002 Emissions (tons)

Plant SO 2 NO

x PMC PMF Boundary Dam 47,338 18,950 7,444 2.996
Shand 15,146 6,463 40 17 Poplar River 47,107 12,864 337 13656



## 7. Best Available Retrofit Technology (BART)

7.1 Introduction

7.1.1 Overview of Paragraph 51.308(e) of the Federa l Regional Haze Regulation - Best Available Retrofit Technology (BA RT) Requirements for Regional Haze Visibility Impairment

The requirements for Best Available Retrofit Techno logy (BART) are found in Section 51.308(e) of the federal regional haze regulation.

Paragraph (e) has six subparagraphs which identify the requirements as follows:

1. 51.308(e)(1) - BART for individual sources; 2. 51.308(e)(2) and (3) - An emissions trading pro gram, or other alternative measure, rather than to require sources subject to BART to install , operate, and maintain BART; 3. 51.308(e)(4) - Participation in the EPA adm inistered Clean Air Interstate Rule (CAIR) trading programs for sulfur dioxide and nitrogen ox ides; 4. 51.308(e)(5) - Status of BART-eligible sources a fter a state has met the requirements for BART; and 5. 51.308(e)(6) - An exemption from BART requiremen ts for BART-eligible sources.

Section 51.308(e) requires the State to submit an i mplementation plan containing emission limitations representing BART and schedules for com pliance with BART for each BARTeligible source that may reasonably be anticipated to cause or contribute to any impairment of visibility in any mandatory Class I Federal area, u nless the State demonstrates that an emissions trading program or other alternative measures will achieve greater reasonable progress toward natural visibility conditions, or the State partici pates in a Clean Air Interstate Rule (CAIR) trading program.

The Department has decided not to develop an emissi ons trading program or other alternate measures and is not eligible to participate in the CAIR program. Therefore only Sections 308(e)(1), (5), and (6) apply in North Dakota.

Each state implementation plan must contain two ele ments related to BART.

The first, found in Section 308(e)(1)(i), is the re quirement that the State submit a list of the BART-eligible sources in the State.

The second requirement is detailed in Section 308 ( e)(1)(ii) and requires the State to determine and include in the plan BART emission reductions f or each BART-eligible source in the State which may reasonably be anticipated to cause or con tribute to any impairment of visibility in any mandatory Class I area.57

BART must be determined for each visibility-impairi ng pollutant that is emitted by a BARTeligible source which may reasonably be anticipated to cause or contribute to regional haze. The

definition for BART 51.301 reads:

Best Available Retrofit Technology (BART) means an emission limitation based on the degree of reduction achievable through the applicat ion of the best system of continuous emission reduction for each pollutant which is emit ted by an existing stationary facility. The emission limitation must be established, on a c ase-by-case basis, taking into consideration the technology available, the costs o f compliance, the energy and the non air quality environmental impacts of compliance, an y pollution control equipment in use or in existence at the source, the remaining useful life of the source, and the degree of improvement in visibility which may reasonably be a nticipated to result from the use of such technology.

Visibility-impairing pollutants include sulfur diox ide (SO 2 ), nitrogen oxides (NO

x ), particulate matter (PM 10 and PM 2.5 ) volatile organic compounds (VOC), and ammonia (NH 3 ).

In developing source specific emission limits for B ART, the State must take into consideration the control technology available and a number of sp ecific factors:

• The costs of compliance;

• The energy and non-air environmental impacts of com pliance;

• Any existing pollution control technology in use at the source;

• The remaining useful life of the source; and

• The degree of improvement in visibility which may r easonably be anticipated from the use of such technology.

The State has the discretion as to how much weight will be given to each of the factors.

EPA issued final guidance for the determination of BART on July 6, 2005 as 40 CFR Part 51 Appendix Y - Guidelines for BART Determinations Und er the Regional Haze Rule (BART guideline).

The SIP for source-specific BART (51.308(e)(1)) mus t contain the requirement that each source subject to BART install and operate BART as expedit iously as practicable, but in no event later than five years after approval of the implementatio n plan revision by EPA.

The SIP must contain procedures to ensure control e quipment is properly maintained and operated in the BART requirements (51.308(e)(1)(v))

.

Paragraph 51.308(e)(5) provides that after a State has met the requirements for source-specific BART, BART-eligible sources will be subject to the core requirements of Section 51.308(d) in

the same manner as other sources. This would inclu de enforceable emissions limitations, compliance schedules and other measures as necessar y to achieve the reasonable progress goals set out in the long-term strategy to attain natural conditions by 2064.58

Paragraph 51.308(e)(6) provides that even where a B ART-eligible source may reasonably be anticipated to cause or contribute to visibility im pairment, section 169A(c) of the Clean Air Act allows for the exemption of any source from the BAR T requirements if it can be demonstrated that the source, by itself or in combination with o ther sources, is not reasonably anticipated to cause or contribute to significant visibility impai rment. Significant impairment 51.301 is defined

as:

“Significant impairment means, for purposes of Sect ion 51.303, visibility impairment which, in the judgement of the Administrator, inter feres with the management, protection, preservation, or enjoyment of the visit or’s visual experience of the mandatory

Class I Federal area. This determination must be ma de on a case-by-case basis taking into account the geographic extent, intensity, duration, frequency and time of the visibility impairment, and how these factors correlate with (1 ) times of visitor use of the mandatory Class I Federal area, and (2) the frequency and tim ing of natural conditions that reduce visibility.”

EPA believes that the question of whether a source can be reasonably anticipated to cause or contribute to significant visibility impairment req uires an analysis of the cumulative effects of emission sources on a region. Regional modeling wi ll be one appropriate method to determine whether a source could qualify for a BART exemption . If a significant cumulative impact is

demonstrated from the sources across the relevant r egional modeling domain, then any BARTeligible source in the region would most likely be found to be reasonably anticipated to cause or contribute to significant visibility impairment.

A source may apply to EPA for an exemption from the BART requirement. The EPA will grant or deny an application after providing notice and o pportunity for a public hearing. Any exemption granted by EPA must have the concurrence from all affected Federal Land Managers. The requirements for an exemption are found in Sect ion 51.303. The authority to grant an exemption is reserved to EPA and will not be delega ted to a state.



### 7.1.2 Visibility-Impairing Pollutants of Concern

For both BART applicability and degree of visibilit y improvement analyses, the BART guideline specifies that only primary emissions need to be co nsidered. These primary emissions include

SO 2 , NO

x , and direct particulate matter (PM) emissions spec ified as either coarse (PM 10 minus

PM 2.5 ) or fine (PM 2.5 ). If this distinction in size of PM emissions can not be made, it would be appropriate to consider all PM 10 emissions as PM 2.5

.

The BART guideline also discusses volatile organic compounds (VOC) or ammonia (NH 3 ) emissions as possibly impacting visibility. For th e BART-eligible sources identified in North Dakota, these emissions (and associated visibility impacts) are negligible, and therefore the Department will not require inclusion of VOC or amm onia species in BART-related visibility analyses.59

7.1.3 BART Identification Process

The first step in preparing the RH BART SIP is to d evelop a list of all BART-eligible sources

within the State.

The regional haze rule contains the following defin itions in Section 51.301:

BART-eligible source means an existing stationary facility as defined in this section.

Existing stationary facility means any of the follo wing stationary sources of air pollutants, including any reconstructed source, whi ch was not in operation prior to August 7, 1962, and was in existence on August 7, 1 977, and has the potential to emit 250 tons per year or more of any air pollutant. In determining potential to emit, fugitive emissions, to the extent quantifiable, must be coun ted.

(1) Fossil-fuel fired steam electric plants of more than 250 million British thermal units per hour heat input, (2) Coal cleaning plants (thermal dryers), (3) Kraft pulp mills, (4) Portland cement plants, (5) Primary zinc smelters, (6) Iron and steel mill plants, (7) Primary aluminum ore reduction plants, (8) Primary copper smelters, (9) Municipal incinerators capable of charging more than 250 tons of refuse per day, (10) Hydrofluoric, sulfuric, and nitric acid plant s, (11) Petroleum refineries, (12) Lime plants, (13) Phosphate rock processing plants, (14) Coke oven batteries, (15) Sulfur recovery plants, (16) Carbon black plants (furnace process), (17) Primary lead smelters, (18) Fuel conversion plants, (19) Sintering plants, (20) Secondary metal production facilities, (21) Chemical process plants, (22) Fossil-fuel boilers of more than 250 million B ritish thermal units per hour heat input, (23) Petroleum storage and transfer facilities with a capacity exceeding 300,000 barrels, (24) Taconite ore processing facilities, (25) Glass fiber processing plants, and (26) Charcoal production facilities.60

The following three steps identify the key elements in the definition of existing stationary facility

and other related definitions that should be consid ered when determining whether a source is a BART-eligible source.

STEP 1. IDENTIFY EMISSION UNITS IN THE 26 BART LIST ED SOURCE

CATEGORIES.

Listed Source Categories - The facility must fall w ithin one of the 26 listed categories in the definition of existing stationary facility. These are the same categories that are included in the definitions of major source under PSD. PSD guidanc e documents and case history can be used to answer any questions related to the 26 categorie s.

Aggregated Unit Applicability - the definition for existing stationary facility includes stationary sources. Stationary source is defined as:

Stationary source means any building, structure, fa cility, or installation which emits or may emit any air pollutant.

Building, structure, or facility are defined as:

Building, structure, or facility means all of the p ollutant-emitting activities which belong to the same industrial grouping, are located on one or more contiguous or adjacent properties, and are under the control of the same p erson (or persons under common control). Pollutant-emitting activities must be co nsidered as part of the same industrial grouping if they belong to the same Major Group (i. e., which have the same two-digit code) as described in the Standard Industrial Class ification Manual, 1972 as amended by the 1977 Supplement (U.S. Government Printing Offic e stock numbers 4101-0066 and 003-005-00176-0 respectively).

Installation is defined as:

Installation means an identifiable piece of process equipment.

The above definitions have been interpreted by EPA to mean that all of the units within the source that meet the BART criteria should be aggreg ated together to determine if the source is BART-eligible.

STEP 2. IDENTIFY THE STARTUP DATES OF THE EMISSION UNITS.

Date of Operation/Construction/Reconstruction - BAR T review is limited to units that were constructed during a 15-year window between 1962 an d 1977. There are several nuances in the definition of existing stationary facility that mus t be considered when determining if a unit falls within this 15-year window. The unit must not have been in operation prior to August 7, 1962. In operation is defined as:61

In operation means engaged in activity related to t he primary design function of the

source.

The date that the unit is permitted is not importan t to meet this test because the focus is on actual operation of the unit.

In addition, the unit must have been in existence a s of August 7, 1977. In existence is defined as:

In existence means that the owner or operator has o btained all necessary preconstruction approvals or permits required by Federal, State, or local air pollution emissions and air quality laws or regulations and either has (1) begu n, or caused to begin, a continuous program of physical on-site construction of the fac ility or (2) entered into binding agreements or contractual obligations, which cannot be canceled or modified without substantial loss to the owner or operator, to under take a program of construction of the facility to be completed in a reasonable time.

The actual date a unit begins operation may not be important to meet this test. For example, a unit that did not begin operation until 1983 may st ill be considered BART-eligible if the unit had all the necessary preconstruction approvals or perm its and had begun, or caused to begin, a continuous program of physical on-site construction of the facility, or entered into binding agreements or contractual obligations, which cannot be canceled or modified without substantial loss prior to August 7, 1977.

STEP 3. COMPARE THE POTENTIAL TOTAL EMISSIONS FOR E ACH

POLLUTANT FROM THE EMISSION UNITS TO THE 250 TON PE R

YEAR CUT OFF.

Potential Emissions - The emission units that meet the source category and date of construction or operation requirements must then be aggregated t ogether to determine if the combined emission units have the potential to emit 250 tons per year of any air pollutant.

Potential to emit is defined as:

Potential to emit means the maximum capacity of a s tationary source to emit a pollutant under its physical and operational design. Any phy sical or operational limitation on the capacity of the source to emit a pollutant includin g air pollution control equipment and restrictions on hours of operation or on the type o r amount of material combusted, stored, or processed, shall be treated as part of i ts design if the limitation or the effect it would have on emissions is federally enforceable. Secondary emissions do not count in determining the potential to emit of a stationary s ource.

Applicability for BART is determined on a pollutant -by-pollutant basis. The total emissions for each pollutant from all the units at the source remaining after step 2 above is compared to the 250 ton per year cut off.62

Pollutants to be considered include the visibility- impairing pollutants, SO 2 , NO

x , PM 2.5 and PM 10 , VOC, and NH 3

.

Fugitive emissions, to the extent quantifiable, mus t be counted. Fugitive emissions are defined

as:

Fugitive Emissions means those emissions which coul d not reasonably pass through a stack, chimney, vent, or other functionally equival ent opening.

As noted in the definition for Potential to emit, s econdary emissions do not count in determining the potential to emit of a stationary source. Seco ndary emissions are defined as:

Secondary emissions means emissions which occur as a result of the construction or operation of an existing stationary facility but do not come from the existing stationary facility. Secondary emissions may include, but are not limited to, emissions from ships or trains coming to or from the existing stationary facility.

A SOURCE THAT PASSES ALL THREE STEPS IS A BART-ELIG IBLE SOURCE.



### 7.1.4 CALPUFF Screening Model Protocol

The Department has established a protocol for BART- related dispersion modeling applicable to BART-eligible sources in North Dakota. The protocol uses the CALPUFF model and conforms to the requirements of Appendix Y to Part 51- Guide lines for BART Determinations Under the Regional Haze Rule. It follows recommendations for long range transport of Appendix W to Part 51 - The Guideline on Air Quality Models and EPA’s Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary Report and Recomme ndations for Modeling Long Range Transport Impacts. The protocol was reviewed by EPA and Federal Land Manager meteorologists in Denver, CO prior to finalizing.

The protocol, “Protocol for BART-Related Visibility Impairment Modeling Analyses in North Dakota, November 2005”, is included as Appendix A.1 . Both BART applicability and degree of visibility improvement analyses were conducted foll owing this protocol.



### 7.1.5 Screening Impact Threshold

In general, to determine which BART-eligible source s must apply BART, single facility modeling results for PSD Class I areas are compared with a visibility threshold, expressed in deciviews. The Department will follow recommendati ons in the July 6, 2005 BART guideline

which states:

“A single source that is responsible for a 1.0 deci view change or more should be considered to “cause” visibility impairment; a sour ce that causes less than a 1.0 deciview change may still “contribute” to visibility impairm ent and thus be subject to BART .... As63

a general matter, any threshold that you use for de termining whether a source “contributes” to visibility impairment should not b e higher than 0.5 deciviews.”

As a practical matter, the NDDH sees no reason to d istinguish among BART-eligible sources which “cause” visibility impairment versus those so urces which “contribute” to visibility impairment in PSD Class I areas. Therefore, the De partment will generally use one threshold to determine which BART-eligible sources must apply BA RT.

The Department, in accordance with the BART guideli nes, used a contribution threshold of 0.5 deciview for determining which sources were subject to BART. The BART guidelines provide

States the discretion to set a threshold below 0.5 deciviews if “the location of a large number of BART-eligible sources within the State and proximit y to a Class I area justifies this approach.”

This decision was based on several factors:

- It equates to the 5 percent extinction threshold for new sources under the PSD New Source Review rules, - It is consistent with the threshold selected by o ther States in the West (all selected 0.5 dv), - It represents the limit of perceptible change

There are only a few major point sources in North D akota affecting the Class I areas and they are mostly 100 or more miles away, downwind in the prev ailing wind direction. BART screening modeling indicates the visibility impact to either be much greater than 1.0 deciview or 0.5 deciview or less (See Section 7.3.1.), and there wa s no clear rationale or justification for selecting a lower level.

The Department therefore has established 0.5 decivi ew as the threshold to determine which BART-eligible sources must apply BART and included it in the State rules. Definition 2 of NDAC Section 33-15-25-01, Definitions, is:

“Contributes to visibility impairment” means a chan ge in visibility impairment in a Class I federal area of five-tenths deciviews or more (24 -hour average) above the average natural visibility baseline. A source exceeds the t hreshold when the ninety-eighth percentile of the modeling results based on any one year of the three years of meteorological data modeled exceeds five-tenths dec iviews.



### 7.2 BART - Eligible Sources in North Dakota

The ten BART-eligible sources in the State of North Dakota and their locations are listed in Table 7.1. The locations of the BART-eligible sourc es with respect to Class I areas in North Dakota are illustrated in Figure 7.1.64 1

2

3 4 5 6

km 0 100 200 300 400 Key

1 Leland Olds Station/
Stanton Station 2 Milton R Young Station
3 Heskett Station/ Mandan Refinery
4 Coal Creek Station 5 ACS Drayton 6 ACS Drayton (modeled)

BART-Eligible Source Lostwood
Wilderness Area

TRNP South Unit TRNP North Unit

TRNP Elkhorn Ranch Unit

PSD Class I Area Bismarck NDDH Modeling
Domain Table 7.1 BART-Eligible Sources in North Dakota

Source and Unit Location American Crystal Sugar Company Main Boiler and Lime Kiln Drayton, Pembina County Basin Electric Power Cooperative Leland Olds Statio n Unit 1 Stanton, Mercer County Basin Electric Power Cooperative Leland Olds Statio n Unit 2 Stanton, Mercer County Great River Energy Coal Creek Station Unit 1 Falki rk, McLean County Great River Energy Coal Creek Station Unit 2 Falki rk, McLean County Great River Energy Stanton Station Unit 1 Stanton, Mercer County Minnkota Power Cooperative Milton R. Young Station Unit 1 Center, Oliver County Minnkota Power Cooperative Milton R. Young Station Unit 2 Center, Oliver County MDU Resources Group, Inc. R. M. Heskett Station Uni t 2 Mandan, Morton County Tesoro Petroleum Corporation Mandan Refinery Carbon Monoxide Furnace Mandan, Morton County

Figure 7.1 BART-Eligible Sources and Class I Areas in North Da kota65

The BART-eligible sources were identified using the methodology in the Guidelines for BART Determinations Under the Regional Haze Rule, 40 CFR Part 51, Appendix Y, and summarized in

7.1.3.

Eight of the BART-eligible sources are fossil-fuel fired steam electric plants of more than 250 million British thermal units per hour heat input. One is a fossil-fuel fired boiler of more than 250 million British thermal units per hour heat inp ut and a lime plant (the main boiler and the lime kiln at the American Crystal Sugar Company sug ar beet processing plant at Drayton) and one is a process unit at a petroleum refinery (the carbon monoxide furnace at the Tesoro Petroleum Corporation refinery at Mandan).



### 7.3 Determination of BART-Eligible Sources Subject to BART

7.3.1 Sources Subject to BART

The modeled visibility impact of each of the ten BA RT-eligible sources listed in Table 7.1 on the

Class I areas in North Dakota is shown in Table 7.2 . The maximum 24-hour 98 th percentile deciview represents the result for the worst year o f the three years modeled (2000-2002).

The visibility impact of each BART-eligible source is considered significant if the projected change in the maximum 24-hour impact at a Class I a rea compared against natural conditions is equal to or greater than 0.5 deciviews. The source is then subject to BART. If the impact is less than 0.5 deciviews, the source is exempt from BART.

The modeling to determine if each BART-eligible sou rce has a significant impact on visibility was performed by the Department using the CALPUFF m odel following EPA’s Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 S ummary Report and Recommendations for Modeling Long Range Transport I mpacts specified in the Guidelines for BART Determinations Under the Regional Haze Rule, 4 0 CFR Part 51, Appendix Y. The modeling protocol is included in Appendix A as Appe ndix A.1.

After completion of the subject-to-BART screening m odeling, the eight subject-to-BART sources were notified they were subject-to-BART by letters dated November 30, 2005. These letters are attached as Appendix A.3.

The Department was contacted by Montana Dakota Util ities who requested approval to do a more refined CALPUFF screening analysis considering that the Department’s results were slightly above the 0.5 deciview cutoff. MDU submitt ed a refined analysis in May 2006. This analysis is attached in Appendix A.2 and is discuss ed in 7.3.4 below.66 Table 7.2 Individual BART-Eligible Source Visibility Impact o n Class I Areas

Source and Unit Class I Area Maximum 24 Hour

98th Percentile Visibility Impact

Value Deciview Subject to BART or Exempt American Crystal Sugar Company Main

Boiler and Lime Kiln Lostwood

TRNP South Unit

TRNP North Unit

TRNP Elk. Ranch

Unit 0.04

0.04

0.04

0.04 Exempt

Basin Electric Power Cooperative Leland

Olds Station Unit 1

and Unit 2 Lostwood

TRNP South Unit

TRNP North Unit

TRNP Elk. Ranch

Unit 5.42

6.22

5.32

4.49 Subject to BART

Great River Energy

Coal Creek Station

Unit 1 and Unit 2 Lostwood

TRNP South Unit

TRNP North Unit

TRNP Elk. Ranch

Unit 4.04

4.48

3.56

3.04 Subject to BART

Great River Energy

Stanton Station Unit 1 Lostwood

TRNP South Unit

TRNP North Unit

TRNP Elk. Ranch

Unit 1.35

1.68

1.54

1.43 Subject to BART

Minnkota Power Cooperative Milton R. Young Station Unit 1

and Unit 2 Lostwood

TRNP South Unit

TRNP North Unit

TRNP Elk. Ranch

Unit 4.88

6.69

5.58

6.10 Subject to BART

MDU Resources Group, Inc. R. M.

Heskett Station Unit 2 Lostwood

TRNP 0.23 1

0.28 1 Exempt

Tesoro Petroleum Corporation Mandan Refinery Carbon

Monoxide Furnace Lostwood

TRNP South Unit

TRNP North Unit

TRNP Elk. Ranch

Unit 0.04

0.05

0.04

0.04 Exempt

1 MDU BART Screening Results (12/09)67

Detailed descriptions of the seven subject-to-BART sources can be found in the Department BART Determinations in Appendix B and in the Compan y BART Analyses in Appendix C.



### 7.3.2 Exclusion of Tesoro Mandan Petroleum Refinery

The Department single-source modeling for the Tesor o Petroleum Corporation Mandan Refinery Carbon Monoxide Furnace predicted the highest maxim um 24 hour 98th percentile visibility impact value to be 0.05 deciviews at Theodore Roose velt National Park South Unit. This is a

factor of 10 less than the 0.5 deciview threshold f or determining whether a BART-eligible source causes or contributes to visibility impairment. The refore, the unit is exempt and not subject to

BART.



### 7.3.3 Exclusion of American Crystal Sugar Drayton R efinery

The Department single-source modeling for the Ameri can Crystal Sugar Company Drayton Plant Main Boiler and Lime Kiln predicted the highest max imum 24 hour 98th percentile visibility impact value to be 0.04 deciview at all four Class I areas. This is more than a factor of 10 less than the 0.5 deciview threshold for determining whe ther a BART-eligible source causes or contributes to visibility impairment. Therefore, th e unit is exempt and not subject to BART.

As shown in Figure 7.1, the American Crystal Sugar Company Drayton Plant is located outside the Department’s modeling domain. Even if the domai n was extended eastward to incorporate the Drayton plant, the plant is located about 400 k ilometers from the nearest North Dakota Class I area (Lostwood Wilderness Area), and this distanc e is beyond the accepted range of CALPUFF (about 300 kilometers). For modeling purposes, the refore, the Department repositioned the Drayton plant about 100 kilometers to the west, to create a virtual source located just inside the east boundary of the current modeling domain (repre sented by the “ACS Drayton (modeled)” source in Figure 7.1). This adjustment provided a source-receptor distance more consistent with the documented limits of CALPUFF, and should ensure results are conservative.

In addition, the Minnesota Pollution Control Agency modeled the American Crystal Sugar Company Drayton plant and found similar impact leve ls at the Class I areas in Minnesota, Voyagers National Park which is about 300 kilometer s from the plant and Boundary Waters

Canoe Area Wilderness which is about 350 kilometers from the plant.



### 7.3.4 Exclusion of Montana Dakota Utilities Hesket t Unit No. 2

The Department single-source modeling for the Monta na Dakota Utilities R.M. Heskett Station Unit 2 located near Mandan predicted the highest ma ximum 24 hour 98th percentile visibility impact value to be 0.82 deciview at the Theodore Ro osevelt National Park South Unit, and 0.54 deciview at the North Unit, 0.61 deciview at the El khorn Ranch Unit and 0.58 deciview at Lost

wood National Wilderness Area. Because these values were slightly above the threshold of 0.5 deciviews, Montana Dakota Utilities hired a consult ant, ENSR Corporation, to perform a refined68

CALPUFF modeling analysis. The ENSR analysis submit ted June 9, 2006 is included as Appendix A.2.

The ENSR analysis made three refinements to the ana lysis performed by the Department:

- A 1 km grid size was used instead of 3 km, - Particulate matter emissions were speciated into several components that have different light scattering potential, and - The annual average background visibility was used instead of the annual 20 percent best day’s background visibility (as per an EPA court se ttlement agreement).

The results of the refined ENSR analysis predicted the highest maximum 24 hour 98th percentile visibility impact value to be 0.436 deciviews at Lo stwood National Wilderness area in 2001.

The Department had originally reviewed the ENSR ana lysis and found it acceptable. Additionally, MDU has committed to reduce the poten tial sulfur dioxide emissions from Heskett Unit 2 by a minimum of 70 percent within five years of EPA approval of this SIP. This would have reduced sulfur dioxide emissions to 1,847 tons per year from the 2000-2004 emissions of 2,400 tons per year, a 553 tons per year reduction. The Department had determined that Heskett Unit 2 was not subject to BART. See the Department’ s letter of May 8, 2007 in Appendix A.3. The FLMs and EPA have expressed concerns about the modeling that was conducted. MDU agreed to remodel using a revised modeling protocol approved by EPA. The Department

reassessed the determination to exclude Heskett Sta tion Unit 2 following review of the revised modeling. That reassessment shows that Heskett Uni t 2 is not subject to the BART requirements. The results of the analysis using th e protocol as approved by EPA indicated the highest maximum 24-hour 98 th percentile visibility impact value to be 0.28 deci views at TRNP and 0.23 deciviews at LWA. Based upon the refined analysis and the reassessment analysis, Heskett Unit 2 is exempt from the BART requirements

.



### 7.4 Determination of BART Requirements for Subject- to-BART

Sources

7.4.1 Company BART Analyses

The Department met individually with the seven subj ect-to-BART sources in December 2005 and requested they complete and submit BART analyse s within nine months of the notification letters dated November 30, 2005 or by September 1, 2006. The nine month time was required by NDAC 33-15-25-02.1. This was agreed to by the seven sources. They were required to address BART for sulfur dioxide, nitrogen oxides, fine part iculates and condensable particulates.

The Department also requested the sources follow re quirements of Appendix Y to Part 51 - Guidelines for BART Determinations Under the Region al Haze Rule in conducting their analyses.69

The seven BART analyses were submitted in final for m in late 2007 to early 2008. The final company BART analyses are attached as Appendix C.



### 7.4.2 Department BART Determinations

The Department has reviewed the company BART determ inations and conducted its own

determinations for each source. The BART determinat ions followed the methodology of Section IV of Appendix Y to Part 51 - Guidelines for BART D eterminations Under the Regional Haze Rule. This includes identifying the best system of continuous emission reduction taking into

account:

1. The available retrofit control options, 2. Any pollution control equipment in use at the so urce (which affects the availability of options and their impacts), 3. The costs of compliance with control options, 4. The remaining useful life of the facility, 5. The energy and non-air quality environmental imp acts of control options, and 6. The visibility impacts analysis.

A case-by-case top down BART analysis using the fiv e basic steps was followed. The five steps

are:

STEP 1 - Identify all available retrofit technologi es, STEP 2 - Eliminate technically infeasible options,

STEP 3 - Evaluate control effectiveness of remainin g technologies, STEP 4 - Evaluate impacts and document the results, and STEP 5 - Evaluate Visibility impacts.

The Department BART determinations are included as Appendix B. Each BART determination includes a source description including the major b oiler units and the minor sources such as auxiliary boilers, emergency generators, coal/mater ials handling dust controls, and coal storage piles; the site characteristics; BART evaluations f or the major and minor sources; and a permit to construct description.

As detailed in Appendix B, Department BART determin ations included an evaluation of visibility impacts. Single-source modeling was con ducted by the companies to determine the degree of visibility improvement associated with va rious control options for individual units. This modeling was based on EPA guidance for BART de terminations 1 . The Department asked companies to provide a 90 th percentile 24-hr visibility modeling result (delta -deciview) along

with the 98 th percentile 24-hr value referenced in the guidance, because the 90 th percentile would

1 Federal Register, 2005. EPA Regional Haze Regulati ons and Guidelines for Best Available Retrofit Technology (BART) Determinations ; Final Rule. Federal Register, July 6, 2005, Vol.70, No. 128, p. 39103-39172.70

be more consistent with the average of 20% worst days metric utilized for assessing visibility improvement progress under the Regional Haze Rule.

Single-source visibility modeling as provided by th e affected companies was reviewed by the Department, and results related to visibility impro vement were considered in Department BART determinations. Because the Department had concern s regarding the viability of single-source modeling in representing actual visibility improvem ent, however, modeling was given less weight than other factors in the BART determination process.

Though single-source modeling is specified in the B ART guidance for determining degree of visibility improvement, it is clear that this model ing overstates the real single-source visibility impact, given the complexity of multiple-source emi ssions and chemistry actually affecting visibility impairment in Class I areas. As suggest ed by the logarithmic relationship between deciview and light extinction (Section 5.1), an obs erver’s perception of visibility change is affected by the total loading of visibility-affecti ng species in the atmosphere. The observer’s perception of visibility change, due to a reduction (or increase) in visibility-affecting emissions from one source, depends on cumulative visibility i mpact due to all sources. For example, a unit reduction in visibility-affecting emissions (from o ne source) will have only half the visual impact on the observer (delta-deciview) if total light ext inction is 80 Mm -1 compared to the impact if total light extinction is 40 Mm -1 . By excluding the impact of all other sources, th erefore, singlesource modeling is overstating the perceived (delta -deciview) change in visibility. Based on Department experience, single-source modeling resul ts (delta-deciview) tend to be five to seven times larger than results obtained for the same sou rce when it is combined with all other sources in a cumulative analysis.

It is because of this anomaly that the Department h as been very cautious in the interpretation of single-source modeling results, and has focused BAR T determinations on factors other than visibility modeling. In some instances, as discuss ed in Appendix B, the Department has conducted supplemental cumulative modeling to more realistically assess the visibility impact of emissions reductions associated with optional contr ol strategies for individual sources. Cumulative modeling is consistent with the procedur e for determining status with respect to uniform rate of progress goals, which is discussed in Section 8.

BART determinations were made for sulfur dioxide, n itrogen oxides, filterable particulate matter, and condensable particulate matter for all seven sources. A summary of the BART determinations for the main boilers by pollutant fo llows.

Sulfur Dioxide

Three of the seven sources have existing sulfur dio xide removal equipment. Great River Energy

Coal Creek Station Unit 1and Unit 2 and Minnkota Po wer Cooperative Milton R. Young Station Unit 2 are equipped with wet limestone scrubbers. T he existing scrubbers at the Coal Creek Station employ a bypass for flue gas heat and achie ve a 68 percent sulfur dioxide reduction. The lime/fly ash wet scrubber at Milton R. Young Unit 2 achieves a 65 percent sulfur dioxide

reduction.71

Great River Energy Coal Creek Station Unit 1 and Un it 2 - The BART selected by the Department for Unit 1 and Unit 2 is a 95 percent re duction efficiency or a limit of 0.15 pounds per million Btu of heat input on a 30-day rolling a verage basis to be achieved by modifying the existing wet scrubbers and the adding of a new coal dryer serving both units. Unit 1 and Unit 2 emissions may be averaged provided the average does not exceed the limit.

Minnkota Power Cooperative Milton R. Young Station Unit 2 - The BART for sulfur dioxide selected by the Department for Unit 2 is a 95 perce nt reduction efficiency or limit of 0.15 pounds per million Btu of heat input on a 30-day rolling a verage basis to be achieved by modifying the existing wet scrubber. The Consent Decree for Minn kota requires a minimum of 90 percent reduction of sulfur dioxide at Unit 2. The 90 perc ent reduction requirement will apply when Minnkota chooses to comply with the 0.15 lb/10 6 Btu limit. The 90 percent reduction requirement is included in the BART permit.

Minnkota Power Cooperative Milton R. Young Station Unit 1 - Unit 1 has no existing sulfur dioxide removal equipment. The BART selected by the Department for Unit 1 is a 95 percent reduction efficiency on a 30-day rolling average ba sis to be achieved by the installation of a new

wet scrubber. The EPA/State Consent Decree states t hat if Minnkota installs a wet scrubber, they must comply with a 95 percent reduction requirement with no alternative pounds per million Btu of heat input limit.

Basin Electric Power Cooperative Leland Olds Statio n Unit 1 and Unit 2 - Unit 1 and Unit 2 have no existing sulfur dioxide removal equipment. The BART selected by the Department for Unit 1 and for Unit 2 is a 95 percent reduction eff iciency or a limit of 0.15 pounds per million Btu of heat input on a 30-day rolling average basis to be achieved by the installation of new wet scrubbing system.

Great River Energy Stanton Station Unit 1 - Unit 1 has no existing sulfur dioxide removal equipment. Unit 1 burns either lignite coal or sub bituminous coal. Because these coals have different average sulfur contents, Btu contents and chemical characteristics, the Department will issue BART limits appropriate to each coal. The BAR T selected by the Department for Unit 1 is a 90 percent reduction on a 30-day rolling average basis burning either coal or a limit of 0.24 pounds per million Btu of heat input on a 30-day ro lling average basis when burning only lignite coal, a limit of 0.16 pounds per million Btu of hea t input on a 30-day rolling average basis when burning subbituminous coal, and weighted average em ission limit when burning a combination of lignite and subbituminous coal.

The sulfur dioxide emissions before and after BART control, the BART controls, and the sulfur

dioxide emission limits for each of the seven sourc es are summarized in Table 7.3.72 Table 7.3

BART-Level Emissions Reductions From the 2000-2004

Sulfur Dioxide Average

Source and

Unit 2000-2004

Average

Emissions Tons per

Year Baseline

Level of

Control

% Reduction BART Level

of Control

%

Reduction* Control

Device Emissions

after Controls Tons per

Year** Emission

Reduction Tons per

Year** Emission

Limit

Basin Electric

Power Cooperative

Leland Olds

Station Unit 1 16,666 0% 95% New Wet

Scrubber 1,376 15,290 95% reduction

or 0.15 lb/10 6
Btu 30 day rolling average

Basin Electric

Power Cooperative

Leland Olds

Station Unit 2 30,828 0% 95% New Wet

Scrubber 2,530 28,298 95% reduction

or 0.15 lb/10 6
Btu 30 day rolling average

Great River Energy Coal

Creek Station

Unit 1 14,086 68% 95% Modified Existing Wet

Scrubber and Coal Dryer 3,781 10,305 95% reduction

or 0.15 lb/10 6
Btu 30 day rolling average

Great River Energy Coal

Creek Station

Unit 2 12,407 68% 95% Modified Existing Wet

Scrubber and Coal Dryer 3,621 8,786 95% reduction

or 0.15 lb/10 6
Btu 30 day rolling average

Great River Energy

Stanton

Station Unit 1 8,312 0% 90% New Spray Dryer and

Fabric Filter 1,179 7,133 90% reduction

or 0.24 lb/10 6
Btu (lignite) or

0.16 lb/10 6
Btu (PRB) 30 day rolling

average
Minnkota

Power Cooperative

Milton R. Young Station

Unit 1 20,148 0% 95% New Wet

Scrubber 1,007 19,141 95% reduction 30 day rolling

average

Minnkota

Power Cooperative

Milton R. Young Station

Unit 2 12,404 65% 95% Modified Existing Wet

Scrubber 2,739 9,665 95% reduction; or

90% reduction

and 0.15 lb/10 6
Btu 30 day rolling average
Total 114,851 ---- ---- ---- 16,233 98,618 ----

*Based on the two year baseline emission rate for B ART. ** Based on the average 2000-2004 operating rate an d emission rates.

Nitrogen Oxides

There are many different technologies available for controlling nitrogen oxides emissions from coal fired boilers. The technical feasibility for a particular technology is dependent on the type and size of the boiler and the type of coal being c ombusted. The types of boiler used at the seven BART sources in the state are cyclone (3), tangenti ally-fired pulverized coal (2), and wall-fired pulverized coal (2). The types of coal burned in th e state are lignite coal with varying73

characteristics from several different mines near t he plants and subbituminous coal from the Powder River Basin (PRB) in Wyoming and Montana.

The nitrogen oxides control technologies that are a pplicable to a particular boiler are listed in the Company BART Analyses in Appendix C and in the Depa rtment BART Determinations in Appendix B.

One technology, selective catalytic reduction (SCR) , has one of the highest nitrogen oxides removal rates (in the range of 90 percent) and has been commercially installed on many different types of boilers burning different types of coal. H owever, it has never been installed on any type of boiler burning North Dakota lignite. The only pi lot scale testing conducted on North Dakota lignite failed after two months. The seven BART so urces determined SCR is not technically

feasible for installation on boilers in North Dakot a burning lignite coal. The Department agrees that high dust SCR is not technically feasible; how ever, low dust and tail end SCR are considered technically feasible. A detailed discuss ion on the technical feasibility of SCR is provided in Appendix B.5. The BART for nitrogen oxi des for each source follows:

Basin Electric Power Cooperative Leland Olds Statio n Unit 1 - This unit is a wall-fired pulverized coal boiler combusting primarily lignite coal (80-100%) and PRB subbituminous coal (20-0%). The existing nitrogen oxides control equip ment is low NO

x burners installed in 1995. The BART selected by the Department is a limit of 0 .19 pounds per million Btu of heat input on a 30-day rolling average basis. This limit is to be achieved by the installation of selective noncatalytic reduction (SNCR) and basic separated o verfire air (SOFA).

Basin Electric Power Cooperative Leland Olds Statio n Unit 2 - This unit is a cyclone boiler combusting primarily lignite coal (80-100%) and PRB subbituminous coal (20-0%). The unit has no existing nitrogen oxides control equipment. The BART selected by the Department is a limit of 0.35 pounds per million Btu of heat input on a 30-day rolling average basis. This limit is to be achieved by the installation of selective non catalytic reduction (SNCR) and advanced separated overfire air (ASOFA).

Great River Energy Coal Creek Station Unit 1 and Un it 2 - Unit 1 and Unit 2 are identical tangentially-fired pulverized coal boilers combusti ng lignite coal. The existing nitrogen oxides control equipment is low NO

x burners (LNB) and separated overfire air (SOFA). T he BART selected by the Department for each unit is a limit of 0.17 pounds per million Btu of heat input on a 30-day rolling average basis. This limit is to be achieved by the use of the existing low NO

x burners (LNB) and modified/additional separated ove rfire air (SOFA).

Great River Energy Stanton Station Unit 1 - Unit 1 is a wall-fired pulverized coal boiler combusting PRB subbituminous coal and lignite coal. The existing nitrogen oxides control equipment is low NO

x burners. The BART selected by the Department is a limit of 0.29 pounds per million Btu of heat input on a 30-day rolling a verage basis when burning only lignite coal, a limit of 0.23 pounds per million Btu of heat input on a 30-day rolling average basis when burning subbituminous coal, and a weighted average emission limit when burning a combination of lignite and subbituminous coal. These limits are to be achieved by the installation of low NO

x burners (LNB), overfire air (OFA), and selective no ncatalytic reduction (SNCR).74

Minnkota Power Cooperative Milton R. Young Station Unit 1 and Unit 2 - Unit 1 and Unit 2 are both cyclone boilers burning lignite coal. The unit s have no existing nitrogen oxides control equipment. The BART selected by the Department for Unit 1 is a limit of 0.36 pounds per million Btu of heat input on a 30-day rolling avera ge basis and for Unit 2 is a limit of 0.35 pounds per million Btu of heat input on a 30-day ro lling average basis. These limits will be achieved by the installation of selective noncataly tic reduction (SNCR) and advanced separated overfire air (ASOFA). These limits do not apply dur ing startup. During startup, NO

x emissions from Unit 1 shall not exceed 2070.1 pounds per hour on a 24-hour rolling average basis and 3995.6 pounds per hour from Unit 2 on a 24-hour rol ling average basis.

The nitrogen oxides emissions before and after BART control, the BART controls, and the nitrogen oxide emission limits for each of the seve n sources are summarized in Table 7.4.

Table 7.4

BART-Level Emissions Reductions From the 2000-2004

Nitrogen Oxides Average

Source and

Unit 2000-2004

Average

Emissions Tons per

Year Baseline Level

of Control

% Reduction BART Level

of Control

% Reduction* Control

Device Emissions

after Controls Tons per

Year** Emission

Reduction Tons per

Year** Emission Limit

Basin Electric

Power Cooperative

Leland Olds

Station Unit 1 2,501 0% 42% SOFA and

SNCR 1,744 757 0.19 lb/10 6 Btu 30 day rolling

average

Basin Electric

Power Cooperative

Leland Olds

Station Unit 2 10,422 0% 54.5% ASOFA and

SNCR 5,904 4,518 0.35 lb/10 6 Btu 30 day rolling

average

Great River Energy Coal

Creek Station

Unit 1 5,116 0% 30% SOFA 4,285 831 0.17 lb/10 6 Btu 30 day rolling

average

Great River Energy Coal

Creek Station

Unit 2 5,391 0% 30% SOFA 4,104 1,287 0.17 lb/10 6 Btu 30 day rolling

average

Great River Energy Stanton

Station Unit 1 2,048 0% 45% LNB, Overfire

Air and SNCR 1,425 623 0.29 lb/10 6 Btu lignite coal 0.23

lb/10 6 Btu PRB coal 30 day rolling average

Minnkota Power Cooperative Milton R. Young

Station Unit 1 8.665 0% 58.1% ASOFA and

SNCR 3,857 4,808 0.36 lb/10 6 Btu 30 day rolling

average

Minnkota Power Cooperative Milton R. Young

Station Unit 2 14,705 0% 58.0% ASOFA and

SNCR 6,392 8,313 0.35 lb/10 6 Btu 30 day rolling

average

Total 48,848 ---- ---- ---- 27,711 21,137 ----

*Based on the two year baseline emission rate for B ART. ** Based on the average 2000-2004 average operating rate.75

Filterable Particulate Matter

Filterable particulate matter is solid and liquid ( non-condensable) matter that is captured in the front half of EPA test method five, the standard te st method for determining particulate

emissions from boilers.

The existing control devices for filterable particu late matter on all seven boilers are dry electrostatic precipitators (ESPs) with control eff iciencies of 99+ percent. Each unit has an existing particulate emission limit of 0.1 pounds p er million Btu of heat input.

Recent test results submitted to the Department sho w the actual emissions from the seven units average 0.03 to 0.05 pounds per million Btu of heat input with occasional values approaching 0.07 pounds per million Btu of heat input.

Upgrading or replacing existing ESPs could reduce t he particulate emission rates to 0.013 to 0.015 pounds per million Btu of heat input. However , the BART analyses conducted by the

sources indicate the cost effectiveness in dollars per ton is unreasonable and there is very little benefit to visibility in the federal Class I areas.

The existing particulate emissions from all seven b oilers are very low, ranging from 74 tons per year, 2000-2004 average, at Stanton Station Unit 1 to 589 tons per year, 2000-2004 average, at Coal Creek Station Unit 2. The BART screening model ing indicates the maximum visibility impact improvement from reducing actual existing em issions levels of approximately 0.03 pounds per million Btu of heat input to 0.015 pound s per million Btu of heat input at any Class I area from any of the seven sources was 0.037 decivi ews 98th percentile or less. Detailed particulate emissions data and modeling visibility impact improvement data for each source can be found in the Department BART determinations in A ppendix B.

The Department has determined that the BART for fil terable particulate matter for all seven sources is no additional controls and allowable par ticulate emission rate of 0.1 pounds per million Btu of heat input be reduced to 0.07 pounds per million Btu of heat input for five of the seven units. The Minnkota Power Cooperative Milton R. Young Station Unit 1 and Unit 2 are subject to an EPA/State consent decree for New Sour ce Review violations. The consent decree requires filterable particulate emissions not to ex ceed 0.030 pounds per million Btu of heat input. Therefore 0.030 pounds per million Btu of heat inpu t will be the BART limit for these two units.

Condensable Particulate Matter (PM 10 )

Condensable particulate matter is made up of both o rganic and inorganic substances. Organic condensable particulate matter will be made up of o rganic substances, such as volatile organic compounds, which are in a gaseous state through the air pollution control devices but will eventually turn to a solid or liquid state. The pr imary inorganic substance expected from the boiler is sulfuric acid mist, with lesser amounts o f hydrogen fluoride and ammonium sulfate.76

Since sulfuric acid mist is the largest component o f condensable particulate matter, controlling it will control most of the condensable particulate ma tter. The options for controlling sulfuric acid mist are the same options for controlling sulfur di oxide. These include wet and dry scrubbers. Three of the sources have existing wet scrubbers th at will be upgraded. Three of the remaining four units will be equipped with new wet scrubbers and one with a dry scrubber/baghouse system. These technologies will achieve greater tha n 40-60 percent reduction of sulfuric acid mist emissions. Changes that would provide addition al reductions are economically infeasible considering the minimal improvement in visibility t hat could be achieved.

The control of volatile organic compounds at power plants is generally achieved through good combustion practices. The Department is not aware of any BACT determination at a power plant that resulted in any control technology being used. BACT has been found to be good combustion practices which are already in use since it minimizes the amount of fuel to generate electricity.

EPA document AP-42, Compilation of Air Pollutant Em ission Factors, indicates the emission rate of condensable particulate matter could be exp ected to be 0.02 pounds per million Btu. This

emission rate is less than the current emissions of filterable particulate matter and the emissions of filterable particulate matter were determined to have a negligible impact on visibility.

Having considered all the factors, the Department h as determined that BART for condensable particulate matter is represented by good sulfur di oxide control and good combustion control. Since the primary constituent of condensable partic ulate matter is sulfuric acid mist which is controlled proportionately to the sulfur dioxide co ntrolled, the BART limit for sulfur dioxide can act as a surrogate for condensable particulate matt er along with a requirement for good combustion practices.

BART Modifications Description

A summary description of the BART modifications pro posed at each of the seven subject-toBART sources follows:

Basin Electric Power Cooperative Leland Olds Statio n Unit 1 and Unit 2 - A wet scrubbing system will be installed to remove sulfur dioxide f rom the flue gas of each unit. Nitrogen oxides emissions from Unit 1 will be controlled by basic s eparated overfire air (SOFA) and selective noncatalytic reduction (SNCR). Nitrogen oxides from Unit 2 will be controlled by advanced separated overfire air (ASOFA) and selective noncat alytic reduction (SNCR).

Great River Energy Coal Creek Station Unit 1 and Un it 2 - Sulfur dioxide emissions will be controlled by the installation of a coal drying sys tem; the installation of trays or new liquid distribution rings (LDRs) and high flow mist elimin ators (MEs) in the existing wet scrubbers; the elimination of the bypass of the wet scrubbers and the modification of the existing stacks for wet operating conditions. Nitrogen oxides emissions wi ll be controlled by the installation of an additional level of separated overfire air (SOFA) i n each boiler.77

Great River Energy Stanton Station Unit 1 - Sulfur dioxide emissions will be controlled by the installation of a spray dryer and fabric filter sys tem (dry scrubber). Nitrogen oxides emissions will be controlled by the installation of low-NO

x burners plus overfire air plus selective noncatalytic reduction (SNCR) technology.

Minnkota Power Cooperative Milton R. Young Station Unit 1 and Unit 2 - Sulfur dioxide emissions will be controlled by the installation of a new wet scrubber on Unit 1 and by upgrading the existing wet scrubber on Unit 2. Nit rogen oxides emissions from both units will be reduced using advanced separated overfire air (A SOFA) and selective noncatalytic reduction (SNCR).

The control technology to be installed on each sour ce unit is described in more detail in the company BART determinations in Appendix C and the D epartment BART determinations in Appendix B.



### 7.4.3 Summary of Emission Reductions

BART for the BART-eligible sources in the State of North Dakota that are significant contributors to visibility impairment in a Class I area are shown in Tables 7.3 and 7.4 for sulfur dioxide and nitrogen oxides. BART is the emission limit for each pollutant based on the degree of reduction achievable through the application of the best system of continuous emission reduction, taking into consideration the technology available, the costs of compliance, the energy and the non-air quality environmental impacts of co mpliance, any pollution control equipment in use or in existence at the source, the remaining us eful life of the source, and the degree of improvement in visibility which may reasonably be a nticipated to result from the use of such technology. The Department BART determination anal ysis for each BART-eligible source is included in Appendix B.

The application of BART to all BART-eligible source s provides an estimated emission reduction from the 2000-2004 average baseline emissions of 98 ,618 tons per year of sulfur dioxide and 21,137 tons per year of nitrogen oxides. These red uctions are shown in Tables 7.3 and 7.4 for

each source and in total.

BART for each BART-eligible source was determined u sing the methodology in the Guidelines for BART Determinations Under the Regional Haze Rul e. 40 CFR Part 51, Appendix Y.



### 7.5 Air Pollution Control Permit to Construct for S ubject-to-BART

Sources

Section V of Appendix Y to Part 51 - Guidelines for BART Determinations Under the Regional Haze Rule requires the State establish enforceable emission limits that reflect the BART determinations and require compliance within a give n period of time. In particular, the State

must establish an enforceable emission limit for ea ch subject emission unit at the source and for each pollutant subject to review that is emitted fr om the source. The Department worked closely78

with the staff of the EPA Region 8 Air Programs off ice to ensure the permit template contents and language were acceptable to meet the requiremen ts of Section V.

The emission limits, monitoring, recordkeeping and reporting requirements specified in the Department BART determination for each subject-to-B ART source are included in a federally

enforceable Air Pollution Control Permit to Constru ct that will be issued by the Department to the owner/operator of the facility before the SIP i s submitted to EPA. The permits are issued by the Department under existing authority pursuant to NDAC Chapter 33-15-14 and Chapter 33-

15-25.

There are four Permits to Construct, one for both U nit 1 and Unit 2 at the Basin Electric Power Cooperative Leland Olds Station, one for both Unit 1 and Unit 2 at the Great River Energy Coal Creek Station, one for Unit 1 at the Great River En ergy Stanton Station, and one for Unit 1 and Unit 2 at the Minnkota Power Cooperative Milton R. Young Station. The four permits are included in Appendix D.



### 7.5.1 Enforceable Emission Limits

Enforceable emission limits that reflect the BART d eterminations are included in each Air Pollution Control Permit to Construct as permit con dition II.A.1. Conditions for sulfur dioxide are in II.A.1.a., nitrogen oxides in II.A.1.b., and filterable (non-condensable) particulate matter in

II.A.1.c. Each Air Pollution Control Permit to Con struct is incorporated as a part of this Regional Haze SIP.

As required by Section V of Appendix Y, the limitat ions for sulfur dioxide and nitrogen oxides specify an averaging time of a 30-day rolling avera ge, and contain a definition of “boiler operating day” which is any 24-hour period between 12:00 midnight and the following midnight during which any fuel is combusted at any time at t he steam generating unit.



### 7.5.2 Monitoring, Recordkeeping, and Reporting Requ irements

Monitoring, recordkeeping, and reporting requiremen ts have been included in each Air Pollution Control Permit to Construct. The owner/operator is required to conduct monitoring, recordkeeping and reporting as required by NDAC Cha pter 33-15-14-06, Title V Permit to Operate and NDAC 33-15-21, Acid Rain Program (40 CF R 72, 75, and 76). The conditions in each source’s existing Title V operating permit wil l be revised as necessary to cover the new BART emissions limits as they are included these pe rmits. Monitoring requirements are found in permit condition II. A. 4, recordkeeping requiremen ts are found in II.A.5, and reporting requirements are found in II. A. 6.79



### 7.5.3 Operating and Maintenance Requirements

Item 51.308(e)(1)(v) of the EPA BART rule requires that each source subject to BART maintain the control equipment and establish procedures to e nsure such equipment is properly operated. This requirement is also included in the state rule s at NDAC 33-15-25-02.3.

Each Air Pollution Control Permit to Construct has condition II. B. 4 which requires that the owner shall at all times, including periods of star tup, shutdown, and malfunction, maintain and operate the BART unit(s) and all other emission uni ts including associated air pollution equipment and fugitive dust suppression operations in a manner consistent with good air pollution control practices for minimizing emission s.



### 7.5.4 Compliance Date

The Department is requiring that each source subjec t to BART shall install and operate BART as expeditiously as practicable but in no event later than five years after approval of the implementation plan revision by EPA as required by Section V of Appendix Y to 40 CFR Part 51 and Item 51.308(e)(1)(iv) of the EPA BART Rule. This requirement is also included in the

State rule as NDAC 33-15-25-02.2.

This requirement is included as Condition II.A.2 in the Air Pollution Control Permit to Construct issued for each source subject to BART. When this implementation plan is approved by EPA, a Title V operating permit will be issued for each so urce incorporating the conditions of the

Permits to Construct.80



## 8. Visibility Modeling

8.1 Introduction

Computer modeling to determine progress with respec t to visibility improvement goals was conducted in support of this North Dakota Regional Haze SIP. The Regional Haze Rule 2 (Rule) specifies that modeling must be applied to demonstr ate reasonable progress toward the goal of achieving natural visibility conditions in each PSD Class I area by 2064. As discussed in Section 5.4, the uniform rate of progress defines the visibility improvement which would be needed for each planning period to achieve natural visibility conditions by 2064. The first planning period begins at the end of the baseline (2004) and termin ates in 2018. The visibility improvement progress needed by 2018 (or 2018 target) is determi ned by interpolating from the uniform rate of progress glide path, as illustrated in Figure 5.5.

Modeling analyses completed in support of the North Dakota SIP and discussed here address the first planning period, and the 2018 target. These analyses assume that the 2018 goal for each Class I area is the uniform rate of progress (glide path) target for 2018. The Regional Haze Rule, however, gives states the option of establishing reasonable progress goals which are independent of the uniform rate of progress. The r easonable progress goals established by a state for 2018 will not necessarily equal the uniform rat e of progress target for 2018 (see Section 10).

To demonstrate reasonable progress with respect to visibility goals for the first planning period, the Rule specifies that visibility on the 20 percen t worst (most impaired) days must improve, while visibility on the 20 percent best (least impa ired) days must not deteriorate, between the base period (2000-2004) and 2018. Computer modelin g was used to project future visibility, accounting for proposed BART controls and other vis ibility-affecting emissions increases/decreases. Modeling was applied in a rel ative sense. Baseline and projected future emission inventories were modeled to develop a futu re/baseline prediction ratio (relative response factor). The ratio was then applied to ba seline monitoring data for visibility-affecting species to project future visibility.

The Western Regional Air Partnership (WRAP) regiona l planning organization has established a Regional Modeling Center (RMC) to assist member sta tes, including North Dakota, with modeling to determine status with respect to the 20 18 goals. The RMC has applied a chemically sophisticated grid model (CMAQ), on a regional basi s, to project future visibility in Class I areas in the WRAP region 3 . The RMC has developed comprehensive base period and future period visibility-affecting emission inventories to use wi th CMAQ, and has performed numerous studies

2 40 CFR 51.308

3 Tonnesen, G., R. Morris, Z. Adelman, et. al., 2006 . 2006 Report for the Western Regional Air Partnership (WRAP) Regional Modeling C enter (RMC). Western Regional Air Partnership, Denver, CO 80202.81

using base period model and monitoring data to eval uate CMAQ performance 4 . Finally, the RMC has applied CMAQ to project 2018 visibility for each Class I area in the WRAP region, including the Theodore Roosevelt National Park and Lostwood Wilderness Class I areas in North

Dakota.

To supplement work done by the WRAP RMC, the North Dakota Department of Health (NDDoH) has conducted further modeling analysis to address 2018 visibility goals for North Dakota Class I areas. Though the NDDoH utilized WR AP RMC results in assessing progress with respect to visibility goals in North Dakota Cl ass I areas, the NDDoH also recognized it would have to develop further modeling capability f or visibility projection in order to address weight of evidence issues not included in WRAP mode ling, such as discounting the impact of international sources. In addition, the NDDoH had concerns regarding the spatial resolution of the WRAP CMAQ simulations, particularly for large p oint sources.

The RMC is applying CMAQ on a national basis using a grid resolution of 36 km, with no plume-in-grid treatment. This means that emissions from point sources are immediately mixed uniformly throughout a 36 km (square) grid cell vol ume, which may overstate the dilution of the plume, and the speed of chemical reactions for spec ies contained in the plume. This may be problematic, especially for sources located relativ ely near Class I areas. Consequently, the contribution of visibility-affecting species from t hese sources may be misrepresented for both base period and future period modeling. This limit ation in treatment of point sources is recognized in CMAQ documentation 5

.

The NDDoH utilized a hybrid modeling approach for d etermining status with respect to the visibility goals. This approach involved nesting t he local NDDoH CALPUFF domain within the WRAP National CMAQ domain, and applying the Lagrang ian CALPUFF model in a retrospective sense to more realistically define pl ume geometry for local point sources. To implement the nesting, hourly output concentrations from WRAP CMAQ were used to set hourly boundary conditions for CALPUFF. The use of CMAQ o utput to set CALPUFF boundary conditions has been suggested by Escoffier-Czaja an d Scire 6 . Location of the NDDoH CALPUFF domain within the National CMAQ domain is i llustrated in Figure 8.1.

Given limitations in the CALPUFF chemistry for othe r species, the NDDoH hybrid modeling system was used for simulation of SO 2 -SO 4 -NO X -HNO 3 -NO 3 chemistry and transport, and thus sulfate (SO 4 ) and nitrate (NO 3 ) predictions, only. Results for all other visibil ity-affecting

4 See WRAP RMC web site at http://pah.cert.ucr.edu/a qm/308/

5 EPA, 1999. Science Algorithms of the EPA Models-3 Community Multiscale Air Quality (CMAQ) Modeling System. Office of Research and Development, Washington DC

20460.

6 Escoffier-Czaja, C., and J. Scire, 2005. Comments on the Computation of Nitrate Using the Ammonia Limiting Method in CALPUFF. Appendix A , Draft Protocol for the Application of the CALPUFF Model for Analyses of Best Available Retrofit Technology (BART), VISTAS.82Figure 8.1WRAP CMAQ Domain and NDDoH CALPUFF Domain83

species, including organic carbon mass (OMC), eleme ntal carbon (EC), fine particulate (Soil), and coarse particulate (CM), were obtained directly from the CMAQ output for the grid cell containing each subject Class I area IMPROVE monito r. CMAQ output was combined with

CALPUFF results for sulfate and nitrate in order to perform necessary light extinction calculations. In this way, the NDDoH benefits from the sophistication of the RMC approach for other particulate components, which reflect a very small percentage of emissions from the local point sources of concern.

WRAP and NDDoH protocols for modeling visibility pr ogress goals generally adhere to EPA Guidance on the Use of Models and Other Analyses fo r Demonstrating Attainment of Air Quality Goals for Ozone, PM 2.5 , and Regional Haze 7 . An evaluation of modeling system performance was conducted first. Then baseline (2000-2004) and future (2018) emission scenarios were modeled in order to develop relative response facto rs (RRFs). Finally, RRFs were applied to baseline IMPROVE monitoring data to project future visibility in North Dakota Class I areas.

Class I areas in North Dakota include the three uni ts of Theodore Roosevelt National Park (TRNP), and the Lostwood Wilderness Area (LWA). IM PROVE monitors are located at the TRNP South Unit and LWA, only. Therefore, these tw o Class I areas were the focus of the modeling analyses. Locations of North Dakota Class I areas, IMPROVE monitor sites

, and larger visibility-affecting sources are depicted in Figure 8.2.

While this presentation (Section 8) addresses both WRAP and NDDoH visibility modeling analyses, focus is on the NDDoH modeling as WRAP pr ocedures are extensively documented elsewhere. The WRAP protocol for regional haze vis ibility modeling is summarized in 2006 Report for the Western Regional Air Partnership (WR AP) Regional Modeling Center (RMC) 8

. The NDDoH protocol for regional haze progress goal modeling is attached as Appendix E to this

document.



### 8.2 Regional Haze Metrics

To address progress in visibility improvement, mode ling is used to provide mass concentrations of visibility-affecting species. These concentrati ons are translated into light extinction using the IMPROVE algorithm. Finally, light extinction is co nverted to deciviews to accommodate comparison with visibility goals. Use of the deciv iew metric to assess baseline visibility, natural visibility, and improvement in visibility was discu ssed in Section 5.

Calculation of light extinction from visibility-aff ecting aerosol concentrations for the WRAP

7 EPA, 2007. Guidance on the Use of Models and Othe r Analyses for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, a nd Regional Haze. Publication No. EPA 454/B-07-002, Office of Air Quality Planning and St andards, Research Triangle Park, NC

27711.

8 See supra note 3.84Figure 8.2Larger Point Sources and PSD Class I Areas3156279101112131448km0 100 200 300 400Point Source Key1 Coal Creek Station2 Leland Olds Station/Stanton Station3 Milton R Young Station4 Heskett Station5 Antelope Valley Station/Great Plains Synfuels6 Coyote Station7 Little Knife Gas Plant8 Tioga Gas Plant9 Colstrip Station10 Celp Boiler11 Lewis & Clark Station12 Poplar River Station13 Boundary Dam Station14 Shand StationLostwoodWilderness AreaTRNP South UnitTRNP North UnitTRNP Elkhorn Ranch UnitPSD Class I AreaBismarckNDDoHModelingDomainIMPROVE Monitor Site85

RMC and NDDoH regional haze analyses is based on th e “new” IMPROVE algorithm 9 . This new system was seen to reduce bias associated with use of the “old” IMPROVE algorithm, and was adopted as an alternative by the IMPROVE Steeri ng Committee in December 2005. The new algorithm splits ammonium sulfate, ammonium nit rate, and organic mass concentrations into two fractions: small and large. The new algor ithm for light extinction is:

b ext = 2.2 x f

s (RH) x [small amm. sulfate] + 4.8 x f L (RH) x [large amm. sulfate]

+ 2.4 x f

s (RH) x [small amm. nitrate] + 5.1 x f L (RH) x [large amm. nitrate] + 2.8 x [small organic mass] + 6.1 x [large organic mass] + 10.0 x [elemental carbon] + 1.0 x [fine soil]

+ 1.7 x f

ss (RH) x [sea salt] + 0.6 x [coarse mass] + Rayleigh scattering (site-specific) + 0.33 x [NO 2 (ppb)]

where

b ext

= light extinction in units of inverse megameters (Mm -1 ),

f

s (RH) = function of relative humidity for small size fraction,

f

L (RH) = function of relative humidity for large size fraction,

f

ss (RH) = function of relative humidity for sea salt, all species concentrations (with exception of NO 2 ) are provided in ug/m 3

, amm. sulfate / amm. nitrate means ammonium sulfate / ammonium nitrate.

Apportionment of total sulfate concentrations into small and large size fractions is defined:

[large amm. sulfate] = [total amm. sulf ate] 2 , for [total amm. sulfate] < 20 ug/m 3
20 ug/m 3

[large amm. sulfate] = [total amm. sulfate], for [ total amm. sulfate] > 20 ug/m 3

[small amm. sulfate] = [total amm. sulfate] - [larg e amm. sulfate]

Similar equations are used to apportion total ammon ium nitrate and total organic matter concentrations into small and large size fractions.

A solution for the NO 2 term in the extinction algorithm is problematic as the IMPROVE network

does not include NO 2 sampling. However, WRAP and the NDDoH have determ ined that the

NO 2 term has very little impact on total light extinct ion. A review of observational NO 2 data from an NDDoH monitoring site in Theodore Roosevelt National Park revealed that readings

were less than the minimum detectable level of 2.0 ppb more than 80% of the time in 2002

.

9 IMPROVE, 2005. New IMPROVE algorithm for estimati ng light extinction approved for use. The IMPROVE Newsletter, Volume 14, Number 4. Air Resource Specialists, Inc., Fort Collins, CO 80525.86

Accordingly, both WRAP and the NDDoH have omitted t he NO 2 term in analyses for future visibility.

The IMPROVE network does include sampling for sea s alt. But monitored values are very low in North Dakota Class I areas. Further, the WRAP R MC found that the CMAQ model was not a reliable predictor for sea salt. Therefore, WRAP h as omitted sea salt as a modeled species, and both WRAP and the NDDoH are assuming a relative res ponse factor of 1.0.

Light extinction is converted to deciview using the following relationship:

dv = 10 x ln(b ext

/ 10)

where

dv = deciview,

b ext = light extinction in units of inverse megameters (Mm -1 ).

Visibility goals are generally expressed as decivie ws.



### 8.3 Projection of Future Visibility

Methodology for WRAP and NDDoH projection of future visibility is based on EPA Guidance on the Use of Models and Other Analyses for Demonst rating Attainment of Air Quality Goals for
Ozone, PM

2.5 , and Regional Haze 10 . The guidance proposes a relative modeling approa ch to project future (2018) visibility, in order to deter mine compliance status with respect to visibility goals at Class I areas. Implementation of the rela tive modeling approach relies on relative response factors (RRFs) which represent the modeled impact of the future (visibility affecting) source emissions inventory divided by the modeled i mpact of the baseline source inventory at Class I areas. These RRFs are applied to baseline IMPROVE monitoring data to project future visibility for each Class I area.

Per the Regional Haze Rule, projection of future vi sibility is needed for the 20% worst and 20% best visibility days at each Class I area. The 20% worst days and 20% best days are determined from Class I area IMPROVE monitoring data for each year for the 5-year baseline period 2000- 2004. Because IMPROVE sampling occurs once every t hree days, the maximum number of monitored days per year would be 122, and the maxim um number of 20% worst or best days per year would be 24.

According to the EPA guidance, worst-day RRFs are d eveloped by comparing the future average predicted mass concentration for 20% worst days to the baseline average predicted mass concentration for 20% worst days, for each visibili ty affecting species. The 20% worst modeled days are temporally consistent with the worst monit ored days, which requires that modeling is

10 See supra note 7.87

based on 2000-2004 meteorological data (i.e., meteo rological data used for modeling represents the same period as baseline monitoring), if all fiv e years are modeled 11 . For each visibility affecting species (SO 4 , NO 3 , OMC, EC, Soil, CM), a single RRF is developed for each Class I area. The RRF is calculated by dividing the predic ted future concentration averaged over all worst days by the predicted baseline concentration averaged over all worst days. Then, future concentrations for each species are projected by mu ltiplying the RRF by the observed species concentration on each of the baseline worst days. The same process is used to develop best-day RRFs, and project best-day concentrations.

The RRF approach can be expressed mathematically:

_ _ X i,j of = X i,j ob (RRF i ) = X i,j ob (X i pf /X i pb )

where

X i,j of

represents projected observed future concentratio n for species i on day j (each of 20% worst days for each baseline year),

X i,j ob represents o bserved baseline (IMPROVE data) concentration for s pecies i on day j (each of 20% worst days for each baseline year),

_ X i pf represents average predicted future concentration for species i (average of 20% worst days),

_ X i pb represents average predicted baseline concentratio n for species i (average of 20% worst days),

RRF i represents the relative response factor for specie s i.

The same system is applied to project 20% best day concentrations.

The set of projected future worst-day concentration s (including all species above) is converted to light extinction through application of the IMPROVE equation (Section 8.2) for each day, then daily light extinction is converted to deciview for each day. Finally, projected daily deciview is averaged over all worst-case days for each year, th en averaged over all years to produce the single future value needed to address visibility go als for each Class I area. This procedure is repeated for projected future best-day concentratio ns.

Both the WRAP RMC and the NDDoH followed this gener al methodology for projecting future visibility-affecting species concentrations, and su bsequently, worst day and best day future

deciview.

11 Because of the resource demands of the CMAQ model, the WRAP RMC limited their visibility modeling analysis to the use of 2002 met eorology, only. Consequently, the NDDoH analysis was likewise limited to 2002 meteorology. The RRFs developed from modeling based on 2002 meteorology were then applied to all five y ears of monitoring data for future projection.88



### 8.4 WRAP Visibility Modeling Methodology

The Western Regional Air Partnership (WRAP) is a Re gional Planning Organization (RPO) representing the western states, including North Da kota. WRAP is one of five RPOs which together cover all states in the country. These RP Os are responsible for assisting states in the development of State Implementation Plans (SIPs) an d Tribal Implementation Plans (TIPs) to address requirements of the Regional Haze Rule, and to assist with other air quality issues.

WRAP has established a Regional Modeling Center (RM C) to conduct visibility modeling and provide technical modeling guidance to support regi onal haze SIPs and TIPs for western states. This RMC reflects a consortium of technical experti se from University of California Riverside, University of North Carolina, and ENVIRON Internati onal Corporation. With funding from the western states, the RMC conducted an extensive mode ling effort to project future visibility for each Class I area in the western United States, inc luding the Class I areas in North Dakota.

WRAP RMC visibility modeling methodology is largely described in Final Report for the Western Regional Air Partnership (WRAP) Regional Mo deling Center (RMC) for the Project Period March 1, 2004 through February 28, 2005 12 and 2006 Report for the Western Regional Air Partnership (WRAP) Regional Modeling Center (RM C) 13

. Specific documentation for most recent baseline and future modeling cases is provid ed in 2002 Planning Simulation Version D 14

and 2018 Preliminary Reasonable Progress Simulation Ver sion A 15 , respectively. These and

other resources can be obtained from the WRAP web s ite at http://pah.cert.ucr.edu/rmc.

Primary modeling tools used by the WRAP RMC include :

• the Fifth-Generation Pennsylvania State University/ National Center for Atmospheric Research (PSU/NCAR) Mesoscale Model (MM5) meteorolo gical modeling system,

• the Sparse Matrix Operator Kernel Emissions (SMOKE) emissions modeling system,

• the Community Multiscale Air Quality (CMAQ) air qua lity modeling system, and

12 Tonnesen, G., R. Morris, Z. Adelman, et. al., 2005 . Final Report for the Western Regional Air Partnership (WRAP) Regional Modeling C enter (RMC) for the Project Period March 1, 2004, through February 28, 2005. Western Regional Air Partnership, Denver, CO

80202.

13 See supra note 3.

14 WRAP, 2008. 2002 Planning Simulation Version D. Western Regional Air Partnership, Denver, CO 80202.

15 WRAP, 2008. 2018 Preliminary Reasonable Progress Simulation Version A. Western Regional Air Partnership, Denver, CO 80202.89

• the PM Source Apportionment Technology extension (P SAT) of the Comprehensive Air Quality Model (CAMx).

The modeling domain established by the RMC includes all of the contiguous United States, and parts of Mexico and Canada (see Figure 8.1). The R MC used the MM5 model to develop the meteorological fields necessary for execution of CM AQ and PSAT within the domain. Grid cell size was specified as 36 kilometers in the horizont al direction, and vertical structure was defined by 19 layers of varying depth. Because of resource and time constraints (primarily related to CMAQ and PSAT), preparation of meteorological data was limited to Year 2002 of the baseline period.

Emissions inventory development for WRAP RMC visibi lity modeling relied primarily on the EPA National Emissions Inventory (NEI), and informa tion collected from states and other RPOs. County emissions data for visibility affecting spec ies, as well as all other species necessary to execute the chemistry in CMAQ and PSAT, were collec ted and processed into the format required by SMOKE. Then SMOKE was executed to appo rtion emissions to the appropriate grid cell and vertical layer within the modeling domain, on an hourly basis. Where appropriate, temporal emissions patterns were applied during the execution of SMOKE. All source categories shown in Table 8.1 were accounted for in the processing of emissions data in

SMOKE.



### Table 8.1

WRAP RMC Source Categories

Source Category

Stationary Point Sources Stationary Area Sources

On-Road Mobile

Off-Road Mobile Biogenic

Oil & Gas

Offshore Platforms Offshore Shipping Road Dust Fugitive Dust

Wind-Blown Dust

Wild Fires

Natural Fires Anthropogenic Fires Agricultural Ammonia

The WRAP RMC has included three basic emissions cas es in their visibility modeling, for performance evaluation and the development of relat ive response factors.

• Case BASE02b reflects year 2002 emissions which are concurrent with the year 2002 meteorology. WRAP used this case for performance e valuations.

• Case PLAN02d reflects a composite interpretation of emissions for the 2000-2004 period. WRAP used this case for the baseline period to gene rate relative response factors.90

• Case PRP18a (Preliminary Reasonable Progress 2018 S cenario A) reflects projected year 2018 emissions. Case PRP18a represents base period emissions projected to 2018, accounting for estimates of the effect of BART cont rols, and assuming other growth and

control factors. WRAP used this case for the futur e period to generate relative response

factors.

Note that WRAP recently completed modeling for an u pdated Case PRP18b future emissions scenario, as discussed in Section 6. Because NDDoH visibility modeling was initiated and largely completed well before the WRAP PRP18b emiss ions inventory and modeling results were available, however, Case PRP18b is not include d in the visibility modeling results discussed in this SIP. For North Dakota sources, C ase PRP18b reflects only a slight decrease in emissions relative to Case PRP18a. Therefore, resu lts and conclusions of the visibility analyses reported here would not be meaningfully changed wit h the use of Case PRP18b emissions.

To define boundary conditions for the WRAP modeling domain, species concentrations for the perimeter of the domain were derived from the globa l GEOS-CHEM model.

Before beginning production modeling for developmen t of RRFs, the WRAP RMC conducted extensive performance evaluations for both CMAQ and CAMx/PSAT. These performance

evaluations were used to refine emissions inventori es and other input conditions. CMAQ was subsequently applied to baseline (PLAN02d) and futu re (PRP18a) emissions inventories to generate RRFs and project future visibility in Clas s I areas. Development of RRFs and projection of future visibility followed default EP A methodology 16 , as outlined in Section 8.3. Finally, PSAT was applied to assess source and spec ies attribution for projected visibility impacts.

Results of WRAP RMC modeling for North Dakota Class I areas are reviewed in Section 8.6.2.



### 8.5 NDDoH Visibility Modeling Methodology

In support of the North Dakota Regional Haze SIP, t he North Dakota Department of Health (NDDoH) conducted refined progress goal visibility modeling to supplement and update the modeling conducted by WRAP RMC. The NDDoH develope d an in-house modeling capability to address weight of evidence issues, and concerns regarding the resolution of the WRAP CMAQ simulations, particularly as applied to large point sources located near Class I areas. As discussed in Section 8.4, WRAP RMC modeling focused on the default EPA methodology for regional haze 17 , and did not address weight of evidence issues suc h as discounting the effect of

16 See supra note 7.

17 See supra note 7.91

international source emissions. The RMC applied CM AQ on a regional basis using a grid resolution of 36 km, with no plume-in-grid treatmen t.

The NDDoH regional haze modeling constitutes a hybr id approach as it involved nesting the

local NDDoH CALPUFF domain within the WRAP National CMAQ domain, and applying the Lagrangian CALPUFF model in a retrospective sense t o more realistically define plume-receptor geometry for local point sources. To implement the nesting, hourly output concentrations from WRAP CMAQ modeling were used to set hourly boundary conditions for CALPUFF. CMAQ output used to set CALPUFF boundary conditions refl ects corresponding WRAP cases for

baseline and future emission inventories.

The hybrid modeling approach was used for simulatio n of SO 2 -SO 4 -NO X -HNO 3 -NO 3 chemistry and transport and, thus, sulfate and nitrate predic tions, only. RRFs and projected future concentrations for other visibility affecting speci es, including organic carbon (OMC), elemental carbon (EC), fine particulate (Soil), and coarse ma ss (CM), were taken directly from the WRAP

RMC results for North Dakota Class I areas. The de ferral to WRAP CMAQ results for these species is based on limitations in the CALPUFF chem istry, and the fact that larger point sources located relatively near North Dakota Class I areas, where CMAQ resolution is a concern, are primarily emitters of SO 2 and NO X . Further, IMPROVE measurements at North Dakota Cl ass I areas indicate that sulfate and nitrate are primary contributors to light extinction on most worstcase days. Individual species contribution to ligh t extinction for worst-case days at Theodore Roosevelt National Park is illustrated in Figure 8. 3. Therefore, weight of evidence assessments should be most affected by changes in sulfate and n itrate concentrations.

The NDDoH used the hybrid modeling system in a supp ortive sense to add value to the original WRAP CMAQ modeling results for sulfate and nitrate. The hybrid system was used to adjust WRAP CMAQ results in order to offset coarseness in the CMAQ resolution for large local point sources, and in order to discount the effect of int ernational (Canadian) sources. Procedures for adjusting WRAP CMAQ results are discussed in Sectio n 8.5.6.

For hybrid modeling, the NDDoH used the State’s poi nt source inventory for SO 2 and NO X , and has imported WRAP RMC data for all other source cat egories (and for point source SO 4 and

NO 3 ) to apportion emissions within the CALPUFF domain. WRAP used the SMOKE emissions

model 18 to develop the emissions inventory for CMAQ. The NDDoH has obtained and processed WRAP SMOKE output to define area source e missions for the CALPUFF domain. The CALPUFF area source emissions inventory include s the species SO 2 , SO 4 , NO X , and NO 3

. In addition, primary SO 4 and NO 3 emissions data were extracted from the SMOKE inven tory for point sources, and apportioned to the CALPUFF domai n as area sources. WRAP CMAQ source categories included in the CALPUFF emissions invent ory are outlined in Table 8.2. Note that WRAP SMOKE output did not contain all four species for some source categories.

18 University of North Carolina, 2007. SMOKE User’s Manual. The Institute for the Environment, University of North Carolina.92Figure 8.3IMPROVE 20% Worst Days – TRNP 20000%10%20%30%40%50%60%70%80%90%100%1 15 19 29 9 12 16 11 19 22 17 5 9 19 23 26 23 2 141 1 1 1 2 2 2 3 4 4 5 8 8 8 8 8 11 12 12

Contribution to Extinction% Ray% SS% CM% Soil% EC% OMC% NO3% SO4DayMonth93 

### Table 8.2 CMAQ-CALPUFF Area Source Categories

Source Category Species Included

All Fires Biogenics Fugitive Dust

On-Road Mobile

Off-Road Mobile

Road Dust

Oil & Gas

Conventional Area

Point SO 2 , NO X , SO 4 , NO 3 NO X SO 4 , NO 3 SO 2 , NO X , SO 4 SO 2 , NO X , SO 4 , NO 3 SO 4 , NO 3 SO 2 , NO X SO 2 , NO X , SO 4 , NO 3 SO 4 , NO 3

The interfacing of CMAQ and CALPUFF modeling system s for the NDDoH hybrid approach is illustrated in the flow diagram in Figure 8.4. Nec essary software for processing input data and projecting future visibility has been developed by the NDDoH.

To confirm effectiveness of the hybrid CMAQ-CALPUFF modeling system, the NDDoH conducted a performance evaluation prior to commenc ing production modeling. The evaluation focused on performance of the hybrid system for sul fate and nitrate concentrations, and prompted changes to some model inputs to improve pe rformance relative to observations. CMAQ performance evaluations conducted by WRAP RMC for OMC, EC, Soil, and CM species are also relevant. The NDDoH Performance e valuation is discussed in Section 8.6.1.

The NDDoH has obtained CMAQ emissions input data (S MOKE output) and hourly concentration output files from the WRAP RMC. CMAQ data used to set CALPUFF boundary conditions and develop the CALPUFF area source inve ntory will be based on WRAP cases BASE02b, PLAN02d, and PRP18a, for performance evalu ation, baseline case, and future case modeling, respectively. These WRAP scenarios are d escribed as follows.

• Case BASE02b reflects CMAQ modeling using year 2002 emissions with year 2002 meteorology. The NDDoH used this case for performa nce evaluations.

• Case PLAN02d reflects CMAQ modeling using composite 2000-2004 emissions with 2002 meteorology. The NDDoH used this case for the base period to generate relative response

factors.

• Case PRP18a (Preliminary Reasonable Progress 2018 S cenario A) reflects CMAQ modeling using projected year 2018 emissions with 2002 meteo rology. Case PRP18a represents base period emissions projected to 2018, accounting for estimates of the effect of BART controls, and assuming other growth and control factors. The NDDH used this case for the future period to generate relative response factors.94SMOKEEmissionsProcessorEmissionsDataCMAQModelEmissionsProcessor(SMOKE2PUFF)CALPUFFDomainArea Emissions(SO2, NOX, SO4, NO3)HourlyPredictedConc.Conc.Processor(CMAQ2PUFF)BoundaryConditions(SO2, NOX, HNO3,SO4, NO3)Conc.Processor(CMAQ2IMPROVE)CALPUFFDomainPt Emissions(SO2,NOX)CALPUFFModel24-hrPredicted Conc.(SO4, NO3)VisibilityCalculation24-hrPredicted Conc.(OMC, EC, Soil, CM)NDDHDatabaseFigure 8.4Hybrid Interfacing of CMAQ and CALPUFF Modeling Systems95

Again, WRAP recently completed modeling for an upda ted Case PRP18b future emissions scenario, as discussed in Section 6. Because NDDoH visibility modeling was initiated and largely completed well before the WRAP PRP18b emiss ions inventory and modeling results were available, however, Case PRP18b is not include d in the visibility modeling results discussed in this SIP. For North Dakota sources, C ase PRP18b reflects only a slight decrease in emissions relative to Case PRP18a. Therefore, resu lts and conclusions of the visibility analyses reported here, although conservative, would not be meaningfully changed with the use of Case

PRP18b emissions.

The modeling system, emissions inventory, other mod el inputs, and procedures for the NDDoH regional haze modeling analysis are discussed in fo llowing Sections 8.5.1 through 8.5.6. A detailed, step-by-step outline of NDDoH visibility modeling procedure is also provided in Appendix E of this report.

Results of the NDDoH hybrid visibility modeling for North Dakota Class I areas are reviewed in

Section 8.6.



### 8.5.1 Hybrid Modeling System

For sulfate and nitrate predictions, the NDDoH appl ied the CALPUFF model, using regional WRAP CMAQ output concentrations to set boundary con ditions for the CALPUFF domain. The CALPUFF computer modeling system includes the CALME T meteorological model 19 , the CALPUFF dispersion/chemistry model 20 , and the POSTUTIL and CALPOST post processing programs. POSTUTIL implements the ammonia limiting method, which provides an adjustment to avoid overstating available ammonia for NO

x to NO 3 conversion chemistry in CALPUFF. In the NDDoH implementation of the CALPUFF system for production visibility modeling, the CALPOST processor was replaced with CALHAZE, a modu le which directly processes relative response factors and projects future visibility, us ing hourly output from CALPUFF (POSTUTIL)

baseline and future model runs.

With the exception of CALHAZE (developed by NDDoH), CALPUFF and associated software was developed and is maintained by TRC Corporation (previously by Earth Tech, Inc.). The versions of CALPUFF and associated programs which t he NDDoH utilized for regional haze modeling are summarized in Table 8.3.

19 Earth Tech, Inc., 2000. A User’s Guide for the Ca lmet Meteorological Model. Earth Tech, Inc., Concord, MA 01742.

20 Earth Tech, Inc., 2000. A User’s Guide for the Ca lpuff Dispersion Model. Earth Tech, Inc., Concord, MA 01742.96 

### Table 8.3 CALPUFF System Versions Applicable For Regional Haze Modeling

Program Version Level

CALMET 5.8 70623

CALPUFF 5.8 70623

POSTUTIL 1.56 70627

The meteorological/computational modeling domain us ed by the NDDoH for CALPUFF visibility modeling is illustrated in Figure 8.5. Dimensions of the domain are 639 kilometers east-west by 459 kilometers north-south, with a hor izontal grid cell size of 3 kilometers. In the vertical, the domain is defined by twelve vertical layers. The domain is sized and positioned to encompass all large visibility-affecting point sour ces located within 250 km of North Dakota Class I areas. Because the domain is relatively la rge for CALPUFF modeling, all location coordinates are based on the Lambert Conformal map projection to mitigate distortions due to

the earth’s curvature.



### 8.5.2 CALMET Input

Input requirements for the CALMET model include var ious meteorological and geophysical data sets, and a control input file with appropriate set tings. Required meteorological data include surface, upper-air, and precipitation observations, and mesoscale model output data fields. Geophysical input data include terrain elevation an d land-use data. Though CALMET may be run with mesoscale model meteorological data, alone (i.e., no observations), the EPA modeling guideline 21 recommends “blending” observations with the mesosc ale model fields. Therefore, the NDDoH included surface and upper-air observatio ns in a blended approach.

Because WRAP RMC modeling was limited to the single year 2002 meteorology due to resource limitations, the NDDoH hybrid approach was necessar ily limited to the same single year of meteorology.

21 CFR, 2005. EPA Guideline on Air Quality Models. 40 CFR (Code of Federal Regulations) Part 51, Appendix W.97Figure 8.5CALPUFF 3-km Meteorological/Computational GridNorth DakotaMontanaCanadaSouth Dakota

459 km639 km98



### 8.5.2.1 Meteorological Data

8.5.2.1.1 Mesoscale Model Data

NDDoH mesoscale model wind fields used with CALMET are based on the National Center for Environmental Predictions (NCEP) Rapid Update Cycle (RUC) forecast model. Mesoscale model fields in the MM5.DAT format required by CALM ET were developed by a contractor 22

. The contractor obtained and archived RUC hourly ini tial analyses from NCEP for years 2000 through 2002. Resolution of these initial analyses was 40 km. The contractor used the ARPS Data Assimilation System (ADAS) to enhance resoluti on to 10 km, and converted the resultant hourly wind fields to the MM5.DAT format recognized by CALMET. The domain of these hourly wind fields is consistent with the CALMET/CA LPUFF domain used by NDDoH (Section 8.5.1).

In the process of model performance evaluation, the NDDoH also tested the hybrid modeling system with the 2002 36-km MM5 data set prepared by the WRAP RMC for CMAQ modeling. Hybrid model performance was similar using either M M5 or RUC mesoscale data.

8.5.2.1.2 Surface Observations

Concurrent surface observations for 2002 were obtai ned in surface hourly abbreviated format from the National Climatic Data Center (NCDC). Dat a were obtained for 40 ASOS and manual

stations located within or near the NDDoH CALMET/CA LPUFF domain. The ASOS/manual observations reflect data from stations operated by the National Weather Service, Federal Aviation Administration, U.S. Air Force, and Enviro nment Canada. Locations of these stations are shown in Figure 8.6.

To compensate for well-documented deficiencies in A SOS cloud data above 12,000 feet,

NDDoH also obtained concurrent GOES ASOS satellite cloud data for all selected surface stations. The satellite hourly observations includ ed cloud amount (sky cover) and cloud height (ceiling height) data above 12,000 feet, and were t herefore used to supplement the ASOS

observations.

NDDoH prepared custom software to merge the ASOS an d satellite data. Earth Tech utility software was then used to quality assure merged dat a, and convert to the format required by CALMET (SURF.DAT). Standard methods were applied t o provide substitutions for missing

22 WindLogics, 2004. RUC Analysis-Based CALMET Meteor ological Data for the State of North Dakota. WindLogics, Inc., St. Paul, MN 55 108.99Figure 8.6CALMET Surface / Upper Air Meteorological StationsBISFARDVLGFKRDRDIKJMSMIBMOTISNN60GGWGDVMLSBILSDYOLFJDNHONRAPABRPIRMBG2WXINLMSPSHRGCCYBRYENYQRYWGSurface StationSurface + Upper-air Station100

data. 23,24 The occurrence of missing data elements in the su rface observations was generally very limited, and within the tolerances suggested b y EPA.

8.5.2.1.3 Upper-Air Observations

Upper-air observations for 2002 were obtained from NOAA’s Earth Systems Research Laboratories (ESRL) in Boulder, Colorado. Upper-ai r sounding files were downloaded from the website ( www.fsl.noaa.gov ) in the original FSL format, which is accepted for CALMET input as the option “NCDC CD-ROM”. Data were obtained for s ix upper-air stations (NWS) located

within or near the NDDoH CALMET/CALPUFF domain. Lo cations of these stations are also shown in Figure 8.6.

Processing of the upper-air data for CALMET input i nvolved using Earth Tech utility software, running custom software written by NDDoH staff, and manual editing of data files. The main Earth Tech program quality checked the upper-air da ta files, output error messages to identify problems in the data to be corrected by the user, a nd converted the data to the format required by CALMET. The NDDoH custom software performed additi onal quality checks, and, combined with manual editing of data files, corrected additi onal errors or problems in the data and filled in for missing data when necessary. Substitutions for missing data generally followed standard EPA guidance. 22,23 Upper-air soundings were processed up to the 500- mb level to accommodate mixing heights up to 4000 meters above ground level at Rapid City, South Dakota. In addition, the main Earth Tech processing program had to be mo dified slightly (corrected) to correctly read longitude for Glasgow, Montana.

8.5.2.1.4 Precipitation Data

Hourly precipitation data for 2002 were obtained fr om NCDC in TD-3240 format. Data were included for 93 NWS hourly recording stations locat ed within or near the NDDoH CALMET/CALPUFF modeling domain. Location of these stations is shown in Figure 8.7.

Earth Tech utility software was employed to quality assure the TD-3240 data, and process it into the format required by CALMET (PRECIP.DAT). No sub stitutions were made for missing data, because CALMET substitutes internally from the near est available station, and the station resolution was relatively good (Figure 8.7).

23 Atkinson, D., and R. F. Lee, 1992. Procedures for Substituting Values for Missing NWS Meteorological Data for Use in Regulatory Air Q uality Models.

24 EPA, 1987. On-Site Meteorological Program Guidanc e for Regulatory Modeling Application. Office of Air Quality Planning and St andards, Research Triangle Park, NC 27711.101Figure 8.7CALMET Precipitation Stations102



### 8.5.2.2 Geophysical Data

CALMET requires specification of terrain elevation, and parameters related to the land-use profile, for each grid cell in the modeling domain. The NDDoH derived terrain elevations from United States Geological Survey (USGS) GTOPO30 data sets for North America central and mountain zones. Land-use profiles were derived fro m the USGS Global Data Set for North

America.

Using CALMET utility software, all gridded terrain and land-use data were processed into the single geophysical file (GEO.DAT) required by CALME T. NDDoH assumed default values relating surface roughness length, albedo, Bowen ra tio, soil heat flux, and leaf area index to landuse type.



### 8.5.2.3 CALMET Control File Settings

CALMET control file settings used for processing ye ar 2002 meteorological data for visibility analyses are generally consistent with guidance fro m the Interagency Workgroup on Air Quality Modeling (IWAQM) 25 . To the extent applicable, the settings are also consistent with the North Dakota alternative protocol for PSD Class I increme nt analyses 26

.

IWAQM recommendations for CALMET control file varia ble settings fall into two categories. IWAQM-defined variables are those for which IWAQM p rovides a default value as a general recommendation for all analyses. User-defined vari ables are those where IWAQM recognizes the input value will need to be tailored for a give n application, and default values are therefore not provided.

For visibility analyses, the NDDoH has established appropriate settings for user-defined variables, and has determined the need to adjust a limited number of IWAQM-defined variables from recommended values, as discussed below. The C ALMET control file user-defined settings, as well as the IWAQM-defined settings which have be en adjusted by NDDoH, are summarized in Table 8.4. IWAQM-defined settings adjusted by N DDoH have a shaded background in the

Table.

25 EPA, 1998. IWAQM Phase 2 Summary Report and Recom mendations for Modeling Long Range Transport Impacts. Publication No. EPA- 454/R-98-019, Office of Air Quality Planning and Standards, Research Triangle Park, NC 27711.

26 NDDoH, 2005. A Proposed Alternative Air Quality M odeling Protocol to Examine the

Status of Attainment of PSD Class I Increment. Nor th Dakota Department of Health, Bismarck,

ND 58506.103

Most of the user-defined settings are intuitive, re lated to parameterization of the meteorological grid used with CALMET, as previously discussed. Th e remaining user-defined variables, (RMAX1, RMAX2, RMAX3, TERRAD, R1, R2) control the i nfluence of mesoscale model data, station observations, and terrain features in devel opment of the final wind field. Settings for

these variables are based on the NDDoH alternative protocol for PSD Class I increment analyses.

NDDoH settings for IWAQM-defined variables are cons istent with IWAQM recommendations, with limited exceptions as established in the alter native protocol for PSD Class I increment analyses. Because the use of mesoscale meteorologi cal data is now being generally recommended for long-range modeling analyses, the I PROG variable has been changed from 0 to 14, which reflects use of MM5 format data (in th is case RUC data) as the initial guess wind field. The ZUPWND setting has been changed for con sistency with default values in recent versions of CALMET (the IWAQM setting reflected def aults for an older version of CALMET). Based on visual feedback testing, IWAQM settings fo r variables related to spatial averaging of mixing heights, MNMDAV and ILEVZI, were adjusted to provide averaging over a larger area.

Because the NDDoH CALMET/CALPUFF modeling domain ex tends into the western part of the upper Great Plains, maximum mixing height setti ngs (ZIMAX/ZIMAXW) were increased

from 3000 to 4000 meters to be consistent with maxi mum mixing heights reported for this region. 27 Note that the CALMET BIAS factors have no effect when mesoscale data are used as the initial guess wind field.



### 8.5.3 CALPUFF Input

Along with the CALMET-processed meteorological data , CALPUFF input requirements for NDDoH hybrid visibility modeling include emissions and stack data, background ozone data, background ammonia data, receptor locations, bounda ry conditions, and input control file settings. These CALPUFF input requirements are dis cussed here.

27 Holzworth, 1972. Mixing Heights, Wind Speeds, and Potential for Urban Air Pollution Throughout the Contiguous United States. EPA Publi cation No. AP-101, Office of Air Programs.104 

### Table 8.4 User-Defined and Non-IWAQM Settings

for CALMET Control File*

Variable Description Value

NSSTA No. of surface stations 40

NUSTA No. of upper-air stations 5

NPSTA No. of precipitation stations 93

IBTZ Base time zone 7

PMAP Map projection

(LCC=Lambert Conformal Conic) LCC

FEAST False easting at origin 0.0

FNORTH False northing at origin 0.0

RLAT0 Origin latitude of projection 44.0N

RLON0 Central meridian of projection 102.0W

XLAT1 Latitude of 1st standard parallel for projection 46.0N

XLAT2 Latitude of 2nd standard parallel for projection 48.5N

DATUM Datum-region for output coordinates NWS-27

NX No. of X grid cells 213

NY No. of Y grid cells 153

DGRIDM Grid spacing (km) 3.0

XORIGKM Southwest grid cell X coordinate -380

YORIGKM Southwest grid cell Y coordinate 140

NZ No. vertical layers 12

ZFACE Cell face heights (m) 0.,20.,50.,90.,140.,200., 270.,370.,500.,1000., 1700.,2500.,4200.

NOOBS No observation mode (0 = no) 0

IPROG Use MM5.DAT file as initial guess wind field

(14=yes) 14105

Variable Description Value

RMAX1 Max. radius of influence of surface observation

(km) 100

RMAX2 Max. radius of influence of upper-air observation

(km) 200

RMAX3 Max. radius of influence over water (km) 200

TERRAD Radius of influence of terrain features (km) 10

R1 Distance from a surface observation station at

which the wind observation and the first guess fiel d are equally weighted (km) 10

R2 Distance from an upper-air observation station at

which the wind observation and the first guess fiel d are equally weighted (km) 10

ISURFT Surface station number used for the surface

temperature for the diagnostic wind field module (Bismarck) 17

IUPT Upper-air station number used to compute the

domain-scale temperature lapse rate for the diagnostic wind field module (Bismarck) 1

ZUPWND Bottom and top of layer through which the domainscale winds are computed (m) 1.,2500.

MNMDAV Max. search distance (in grid cells) for spatial

averaging of mixing ht. and temperature 7

ILEVZI Layer of winds used in upwind averaging of

mixing heights 3

ZIMAX Maximum over land mixing height (m) 4000.

ZIMAXW Maximum over water mixing height (m) 4000.

*Shaded background indicates IWAQM-defined setting adjusted by NDDoH106



### 8.5.3.1 Emissions Inventory

The emissions inventory utilized in the NDDoH hybri d visibility modeling analysis accounted

for all SO 2 -SO 4 -NO X -HNO 3 -NO 3 emission sources located within and outside of the NDDoH CALPUFF domain. The impact of emission sources loc ated outside of the domain was accounted for using the boundary condition feature of CALPUFF, with WRAP CMAQ output concentrations used to set appropriate boundary con centrations. Within the CALPUFF domain,

all SO 2 -SO 4 -NO X -NO 3 emissions were configured as conventional point an d area sources.

Note that HNO 3 is not directly emitted by any visibility affectin g source. However, HNO 3 is an important component of nitrate chemistry (both CMAQ and CALPUFF), and is provided as an output species in CMAQ. Therefore, HNO 3 is included as a boundary concentration for CALPUFF boundary conditions, but it is not directly emitted by any of the visibility affecting sources configured within the CALPUFF domain.

For SO 2 -SO 4 -NO X -NO 3 sources located within the NDDoH CALPUFF domain an d within the North Dakota border, stack data for point sources, including stack operating parameters and SO 2 and NO X emission rates, were obtained from an internal Dep artment database. Point source data were reviewed by NDDoH to confirm viability of all stack parameters, and emission rates were updated, if necessary, to reflect values representa tive of the 2000-2004 period.

For SO 2 and NO X point sources located within the NDDoH CALPUFF dom ain, but outside of North Dakota (South Dakota, Montana, Canada), the N DDoH obtained appropriate stack parameters and emission rates from governing agenci es representing these jurisdictions. Most Montana data was obtained directly from the facilit y operators. Data representing the 2000-2004 period were requested. Data were reviewed by NDDoH to confirm viability of all stack

parameters.

Note that the size threshold for configuring visibi lity-affecting sources as point versus area is generally connected to the availability of point so urce data in the National Emissions Inventory (NEI). All point sources included in the NEI (and located within the NDDoH CALPUFF domain) were configured as point sources for the vi sibility analysis. The exception is oil and gas

related SO 2 sources for which the NDDoH maintains a separate d atabase. These oil and gas related sources, though not included in the NEI, we re also configured as point sources for the visibility analysis.

The location of larger visibility-affecting point s ources within the CALPUFF domain is depicted in Figure 8.8.

All remaining SO 2 -SO 4 -NO X -NO 3 sources located within the NDDoH CALPUFF domain, b ut not included in the North Dakota or adjoining juris diction’s point source inventories, were configured as 36-kilometer area sources using a pre defined grid structure in CALPUFF. The area-source grid is illustrated in Figure 8.8. Emi ssion rates for the CALPUFF area source grid were developed using WRAP CMAQ input (SMOKE output) for the CMAQ grid cells located

within the NDDoH CALPUFF domain. The NDDoH obtaine d the SMOKE output data from

WRAP RMC. Because the location and orientation of the CMAQ and CALPUFF grids are not107Figure 8.8NDDoH Domain - Locations of Larger Point Sources and 36-km Area Source Grid3156279101112131448North DakotaMontanaCanadaSouth DakotaPoint Source Key1 Coal Creek Station2 Leland Olds Station/Stanton Station3 Milton R Young Station4 Heskett Station5 Antelope Valley Station/Great Plains Synfuels6 Coyote Station7 Little Knife Gas Plant8 Tioga Gas Plant9 Colstrip Station10 Celp Boiler11 Lewis & Clark Station12 Poplar River Station13 Boundary Dam Station14 Shand StationPSD Class I Area108

consistent, software was developed by NDDoH to accu rately apportion emissions from 36- kilometer CMAQ grid cells to the 36-kilometer CALPU FF area source grid.

Based on availability in WRAP SMOKE output, the CAL PUFF area source emissions inventory included the source categories and species summariz ed in Table 8.2 . Note that SMOKE output did not include all four species (SO 2 -SO 4 -NO X -NO 3 ) for some source categories. Although NDDoH developed a conventional point source invento ry for SO 2 and NO X , the NDDoH database did not include primary SO 4 and NO 3 emissions for point sources. Therefore, SO 4 and

NO 3 emissions for the point source category were obtai ned from WRAP SMOKE output, and these components of point source emissions were con figured as area sources in CALPUFF.

Based on testing during the performance evaluation, and on consultation with Joe Scire (TRC) 28,29 , area sources in CALPUFF were configured for best model performance, and to be more consistent with the grid cell treatment in CMA Q. This involved proper settings for the CALPUFF “release height” and “initial sigma z” inpu t parameters for area sources.

Emission rates used for both point and area sources reflect total actual tons per year. CALPUFF apportions these total emissions, on a temporal bas is, equally to each hour of the year. The NDDoH tested the use of temporal profiles to vary e mission rates on a seasonal, monthly, or hourly basis, but found that such adjustments made little difference in the hybrid model performance evaluation (see Section 8.6.1). For ex ample, North Dakota electrical generating stations (EGUs) were modeled using an annual profil e of actual hourly emissions for SO 2 and

NO X , and results (compared to default total tons per y ear modeling) were unchanged for most of the metrics included in the comparison. The NDDoH attributes this finding to the fact that the characterization of model output used for developin g RRFs is the average of the 20 percent worst or best day predictions, and this longer-term average was also the focus of the performance evaluation. Using the average of 20 percent of the days in a year serves to dampen out differences attributable to shorter-term temporal v ariations in emissions.

To address hybrid model performance and the develop ment of RRFs, the NDDoH prepared separate emissions inventories for base period, fut ure period, and performance evaluation scenarios. SMOKE data used to apportion area sourc e emissions was based on WRAP cases BASE02b, PLAN02d, and PRP18a for performance evalua tion, base period, and future period modeling, respectively. These WRAP cases are descr ibed as follows.

• Case BASE02b reflects use of year 2002 emissions wi th year 2002 meteorology. NDDoH used this case for performance evaluations.

• Case PLAN02d reflects use of composite 2000-2004 em issions with 2002 meteorology. NDDH used this case for base period modeling to gen erate relative response factors.

28 TRC, 2008. Telephone consultation with Joe Scire, May 29, 2008. Joe Scire, TRC Corporation, Lowell, MA 01854.

29 Joe Scire previously affiliated with Earth Tech, I nc.109

• Case PRP18a (Preliminary Reasonable Progress 2018 S cenario A) reflects use of projected year 2018 emissions with 2002 meteorology. Case PR P18a represents base period emissions projected to 2018, accounting for estimates of the effect of BART controls, and assuming other growth and control factors. NDDoH used this case for future period modeling to generate relative response factors.

To complete emission inventories for the three mode ling scenarios, the NDDoH developed point source inventories (SO 2 and NO X ) consistent with the WRAP cases. For EGUs, the in ventory for performance evaluation was based on actual emis sions for 2002, while the base period inventory assumed the five-year average of 2000-200 4 actual emissions. The future period inventory for EGUs included emission reductions con sistent with BART controls (see Section 6.2), but remained consistent with base period emis sions for non-BART facilities. The possible

addition of new EGUs was also accounted for in the future inventory (e.g., the potential “Gascoyne 500” EGU was added to the future inventor y).

For point sources other than EGUs (reflecting gener ally small sources), the source inventory for performance evaluation was based on 2002 actual emi ssions, and the inventory for base period and future period modeling was relatively consisten t with that used for the performance evaluation. For non-EGU point sources, little chan ge in the emissions inventory is expected between base and future periods. Emissions increas es associated with new sources will be no greater (and likely less) than emissions decreases associated with retiring sources.

When considering weight of evidence options in the NDDoH hybrid visibility modeling analysis, emissions inventories as described above were adjus ted to eliminate sources. For example, when exercising the option to discount the impact of int ernational sources, all Canadian sources of visibility affecting emissions (SO 2 -SO 4 -NO X -NO 3 ) were eliminated from the base and future period inventories (see Section 8.6.3.1). Weight o f evidence assumptions are discussed in

Section 8.6.3.

In developing its emission inventories for hybrid m odeling using the default EPA methodology, as well as weight of evidence options, the NDDoH ad justed WRAP future period emissions (PRP18a) for NO X associated with oil and gas related sources. The total North Dakota oil and gas NO X emissions estimated by WRAP for the future invento ry was about 4.5 times higher than the total estimate for the baseline inventory. Bas ed on recent projections from the North Dakota Department of Mineral Resources, oil and gas activi ty in 2018 is expected to be about 2 to 2.5 times higher than the 2002 level. 30 Moreover, in a subsequent telephone consultation, WRAP representatives admitted that 2018 estimates of NO X related to oil and gas activity in North Dakota may have been overstated 31 . Therefore, the NDDoH applied a constant correcti on to WRAP future oil and gas NO X emissions for all area sources in North Dakota, su ch that total 2018 emissions are 2.5 times higher than total base line emissions for oil and gas related NO X

.

30 ND Department of Mineral Resources, 2008. Decembe r 2, 2008 Electronic Communication from Lynn Helms to Terry O’Clair.

31 WRAP, 2008. December 12, 2008 Telephone Communica tion between representatives

of WRAP and NDDoH.110

The NDDoH also had concerns regarding WRAP estimate s of future Soil (fine particulate) emissions. Because the NDDoH is not directly model ing the Soil species, this concern was related to the RRF developed by WRAP for North Dako ta Class I areas. The Soil RRFs applied by WRAP are 1.13 for TRNP and 1.11 for LWA. Both v alues imply some significant increase in future Soil emissions (or precursors). Given recen t increases in the practice of conservation tillage farming in North Dakota and adjoining state s, and recent decreases in the existence of summer fallow (retiring a portion of cultivated lan d for one growing season), an increase in Soil

emissions between the baseline and 2018 seems unlik ely, with a decrease probable. This issue is

discussed in more detail in Section 9.5.2. The NDD oH addressed the Soil inconsistency by adjusting the TRNP and LWA RRFs to 1.0 to implement the default EPA methodology, as well as weight of evidence options. This value is proba bly still conservative, but more in line with current and predicted future farming practices than RRFs developed by WRAP.



### 8.5.3.2 Boundary Conditions

Boundary conditions account for the additive impact of all emission sources located outside of

the CALPUFF domain. Out-of-domain source emissions generally constitute a large component of total predicted concentrations for sulfate and n itrate species.

The NDDoH is using the boundary condition feature o f CALPUFF to effectively nest the CALPUFF domain within the WRAP CMAQ domain to facil itate its hybrid modeling approach. The use of CMAQ output to set CALPUFF boundary cond itions has been suggested by Escoffier-Czaja and Scire 32 . Location of the NDDoH CALPUFF domain within the WRAP CMAQ domain was illustrated in Figure 8.1.

To implement the feature in CALPUFF, a supplemental boundary condition data file must be provided as part of the CALPUFF input conditions. In this file, the user provides the length and location of boundary segments which follow the peri meter of the Calpuff domain. For each segment, the concentration of each species being mo deled is provided, and an air mass depth is assigned. Species concentrations for boundary segm ents can be updated as frequently as hourly.

For NDDoH hybrid visibility modeling, the length of boundary segments was set to match the resolution of the CALPUFF meteorological/computatio nal grid, which is 3 kilometers. Accordingly, a boundary segment was placed adjacent to each computational grid cell along the perimeter of the domain. Boundary segment hourly c oncentrations for SO 2 -SO 4 -NO X -HNO 3 - NO 3 species were taken from CMAQ hourly output concent ration files provided by WRAP RMC. For each segment, concentrations from the 36- km CMAQ grid cell containing the largest part of the segment were utilized. A constant air mass depth of 3000 meters was assumed for all boundary segments. (Though air mass depth of 1000- 2000 meters is nominally suggested in

32 See supra note 6.111

guidance for CALPUFF boundary conditions 33 , the NDDoH found the use of 3000 meters provided better agreement with observations in perf ormance evaluations.)

Separate boundary condition files were prepared for cases BASE02b, PLAN02d, and PRP18a for performance evaluation, baseline, and future hybrid modeling, respectively.



### 8.5.3.3 Ozone Background

CALPUFF utilizes background ozone values in its che mistry module. The model accepts either a single constant background ozone value, or an inp ut file of hourly ozone values commensurate with the period of meteorological data. The NDDoH uses the hourly ozone file option with CALPUFF, and would regard this as the appropriate i mplementation for visibility modeling (this is also the IWAQM default option). The hourly ozon e file was constructed using year 2002 hourly ozone data obtained from four NDDoH monitori ng sites located within the corridor of primary plume transport between major electric gene rating stations and Theodore Roosevelt National Park (TRNP). These monitoring sites inclu de Hannover, Beulah, Dunn Center and TRNP South Unit. As indicated in Section 8.5.3.6, a constant ozone background value (30 ppb) is also provided in the CALPUFF control file, so th at it can be substituted when the hourly value is missing. This value represents the approximate annual average for North Dakota ozone monitoring sites.



### 8.5.3.4 Ammonia Background

The need for ammonia background concentrations in C ALPUFF is also related to chemistry processing. CALPUFF accepts either a single annual value, or twelve monthly averages from a single site. To achieve a more realistic seasonal progression of sulfate and nitrate predictions, the NDDoH used monthly average ammonia background v alues for CALPUFF hybrid visibility modeling input (note that temporal ammonia resoluti on is improved to hourly in the POSTUTIL processing step described in Section 8.5.4).

Monthly average ammonia concentrations suitable for visibility modeling in North Dakota are provided in Table 8.5. These values were derived f rom data collected at the State’s ammonia monitor located near Beulah. Hourly monitor data f rom years 2001-2002 (data not available for year 2000) were filtered to eliminate data from win d directions associated with sources causing a local bias, then remaining data were processed to p roduce the monthly averages. The Table 8.5 values should be generally representative of backgr ound ammonia concentrations in western

North Dakota.

33 See supra note 6.112 

### Table 8.5 Monthly Ammonia Background Concentrations*

Month Value (ppb)

Jan

Feb

Mar Apr May

Jun 1.22

1.23

1.60

1.94

2.29

1.63

Jul Aug Sep

Oct

Nov

Dec 1.65

1.69

0.98

1.04

1.37

1.06

* Data reflect NDDoH Beulah monitoring si te.



### 8.5.3.5 Receptors

Receptors for NDDoH visibility progress goal modeli ng are located at the TRNP and Lostwood NWA IMPROVE monitoring sites. In its guidance for regional haze modeling 34 , EPA recommends including nearby receptors or grid cells in order to provide spatial averaging of the design concentration. Use of a spatial average add resses possible “migration” of the predicted peak, and some uncertainties in the formulation of the model and model inputs. Therefore, the NDDoH used a 3 by 3 receptor grid (9 receptors) whi ch is centered on the IMPROVE site, at each Class I area. Receptor spacing in the grid is 5 kilometers. Receptor elevation was set to the ground elevation of the IMPROVE monitor site for al l 9 receptors in the grid.

Recognizing that visibility is not necessarily a “g round level” concept, the NDDoH also tested the effect of elevated or “flag pole” receptors. A sensitivity test was conducted using a flag pole elevation of 18 meters, which is one-half the heigh t of the surface layer used in WRAP CMAQ modeling. Results of this test showed a negligible difference compared to predictions for ground level receptors.

34 See supra note 7.113



### 8.5.3.6 CALPUFF Control File Settings

CALPUFF control file settings used for NDDoH hybrid visibility analyses are generally consistent with IWAQM guidance 35 . To the extent applicable, the settings are also consistent with the North Dakota alternative protocol for PSD Class I increment analyses 36

.

IWAQM recommendations for CALPUFF control file sett ings fall into two categories. IWAQM-defined variables are those for which IWAQM p rovides a default value as a general recommendation for all analyses. User-defined vari ables are those where IWAQM recognizes the input value will need to be tailored for a give n application, and default values are therefore not provided.

For visibility analyses, the NDDoH has established appropriate settings for user-defined variables, and has determined the need to adjust a limited number of IWAQM-defined variables from recommended values, as discussed below. The C ALPUFF control file user-defined settings, as well as the IWAQM-defined settings whi ch have been adjusted by NDDoH, are summarized in Table 8.6. IWAQM-defined settings ad justed by NDDoH have a shaded background in the table.

Most of the user-defined settings are intuitive, in volving variables related to defining the meteorological/computational grid, variables relate d to the Lambert map projection, and the use of default values for dry and wet deposition parame terization. The variable IRESPLIT was set such that puffs are eligible for splitting on any h our of the day.

NDDoH settings for IWAQM-defined variables are equi valent to IWAQM recommendations, with exception of settings for a limited number of variables related to puff splitting, dispersion, and mixing height. Variable MSPLIT was set to allo w puff splitting, as this option is generally recommended when modeling source-receptor distances of 200 km or more. Based on performance testing of the CALPUFF model for PSD Cl ass I increment modeling 37 , the NDDoH used adjusted settings for dispersion-related varia bles MDISP and MPDF, and for variables IVEG and ROLDMAX, as these adjustments provided bet ter model performance. NDDoH settings for MDISP and MPDF, reflecting the use of micrometeorological variables in calculating dispersion, are also more consistent wi th dispersion treatment in the local-scale

model AERMOD 38 . Values for background ozone and ammonia (variabl es BCKO3 and

35 See supra note 20

36 See supra note 21.

37 See supra note 21.

38 EPA, 2004. User’s Guide for the AMS/EPA Regulator y Model – AERMOD. Publication No. EPA-454/B-03-001, Office of Air Qua lity Planning and Standards, Research Triangle Park, NC 27701.114 

### Table 8.6 User-Defined and Non-IWAQM Settings

for CALPUFF Control File*

Variable Description Value

IBTZ Base time zone 7

NSPEC Number of chemical species 5

NSE Number of chemical species emitted 4

MSPLIT Allow puff splitting (1=yes) 1

MDISP Method used to compute dispersion coefficients 2

MPDF PDF used for dispersion under convective

conditions (1=yes) 1

PMAP Map projection

(LCC=Lambert Conformal Conic) LCC

FEAST False easting at origin 0.0

FNORTH False northing at origin 0.0

RLAT0 Origin latitude of projection 44.0N

RLON0 Central meridian of projection 102.0W

XLAT1 Latitude of 1st standard parallel for projection 46.0N

XLAT2 Latitude of 2nd standard parallel for projection 48.5N

DATUM Datum-region for output coordinates NWS-27

NX No. of X grid cells 213

NY No. of Y grid cells 153

NZ No. vertical layers 12

DGRIDM Grid spacing (km) 3.0

ZFACE Cell face heights (m) 0.,20.,50.,90.,140.,200 .,270.,370.,500.,1000., 1700.,2500.,4200.

XORIGKM Southwest grid cell X coordinate -380

YORIGKM Southwest grid cell Y coordinate 140115

Variable Description Value

IBCOMP Southwest X-index of computational grid 1

JBCOMP Southwest Y-index of computational grid 1

IECOMP Northeast X-index of computational grid 213

JECOMP Northeast Y-index of computational grid 153

Dry Gas Dep. Chemical parameters of gaseous deposition

species Model defaults

Dry Part. Dep. Chemical parameters of particulate deposition

species Model defaults

IVEG Vegetative state in unirrigated areas (2=active

and stressed vegetation) 2

Wet Dep. Wet deposition parameters Model defaults

BCKO3 Monthly ozone background concentration (ppb) 30.0**

BCKNH3 Monthly ammonia background concentration

(ppb) Table 8.5

XMAXZI Maximum mixing height 4000.

IRESPLIT Hours when puff is eligible for vertical split hours 1-24

ROLDMAX Vertical puff split allowed only when the ratio of

last hour’s mixing height to max. mixing height experienced by the puff is smaller than this value 0.33

NSPLITH Number of puffs that result when a puff is split

horizontally 5

SYSPLITH Minimum sigma-y (grid cell units) of puff before

it may split horizontally 1.0

SHSPLITH Minimum puff elongation rate (SYSPLITH/hr)

due to wind shear, before it may split horizontally 2.0

CNSPLITH Minimum concentration (g/m 3 ) in puff before it

may split horizontally 1.0E-07

NREC Number of discrete receptors 18

* Shaded background indicates IWAQM-defined settin g adjusted by NDDoH

**Use same value for each month.116

BCKNH3, respectively) were set to be consistent wit h local monitoring data. Maximum mixing height (XMAXZI) was set to 4000 meters for consiste ncy with CALMET settings.



### 8.5.4 POSTUTIL Input

Because CALPUFF allows the full amount of the speci fied background concentration of ammonia to be available to each puff for forming ni trate, the same ammonia may be used multiple times, resulting in an overestimate of nit rate formation. The POSTUTIL processor provides repartitioning of total nitrate at the receptor location to adjust for over-counting of ammonia in the CALPUFF chemistry. This repartition ing in POSTUTIL is commonly referred to as the ammonia limiting method 39 . The repartitioning process in POSTUTIL generates a modified hourly concentration file in the same form at as the input CALPUFF hourly concentration file. Species HNO 3 and NO 3 , only, are modified in the repartitioning process. Concentrations for all other species remain unchang ed.

To implement the ammonia limiting method, POSTUTIL requires an input control file, the hourly concentration output file from CALPUFF, and (optionally) an hourly file of ammonia background concentrations. Among other intuitive i nput assignments (file names and carryover of settings from CALPUFF), the POSTUTIL input contr ol file specifies the setting for the MNITRATE parameter, which is related to the method of nitrate repartitioning. The control file also provides the source and temporal resolution fo r ammonia background concentrations to be used in nitrate repartitioning. POSTUTIL provides for the use of annual, monthly, or hourly ammonia background concentrations from a single sit e. By allowing use of hourly ammonia background, POSTUTIL improves on the maximum tempor al resolution available in CALPUFF (monthly).

The POSTUTIL processor also accommodates the 3-step ammonia limiting method, which is used to determine the contribution of a subgroup of sources (from the complete source inventory) to total nitrate formation. Effectively, the 3-ste p method allows consideration of the effect of excluded sources on the model chemistry (e.g., excl uded sources still “use up” some of the available ammonia). The MNITRATE parameter is used to control processing for each step of the 3-step sequence. The 3-step ammonia limiting m ethod requires three separate executions of POSTUTIL. Input/output for the 3 steps, along with appropriate MNITRATE settings, is

outlined in Table 8.7.

39 Escoffier-Czaja, C., and J. Scire, 2002. The Effe cts of Ammonia Limitation on Nitrate Aerosol Formation and Visibility Impacts in Class I Areas. Earth Tech, Inc., Extended Abstract.

12 th Joint Conference on the Applications of Air Pollut ion Meteorology with the Air and Waste Management Association, American Meteorological Soc iety, J5.13.117 

### Table 8.7 3-Step Ammonia Limiting Method

Step MNITRATE

Setting Description

1 1 Using CALPUFF hourly concentration file for entire source inventory as input, repartitioning is performed bas ed on entire source inventory. Modified hourly concentra tion file is created (affects HNO 3 and NO 3 species).

2 0 Using Step 1 modified hourly file as input, new spe cies names are assigned to HNO 3 and NO 3 (HNO3ALL and NO3ALL). Hourly concentration file containing only renamed species is created.

3 2 Using both CALPUFF new hourly concentration file fo r source group (subset of entire source inventory in Step 1) and Step 2 hourly concentration output file (HNO3AL L and NO3ALL species representing entire source inventory ), repartitioning is performed based on the source gro up contribution to the entire source inventory. Modif ied hourly concentration file is created (affects HNO 3 and NO 3 species).

The NDDoH utilized POSTUTIL and the ammonia limitin g method in its hybrid modeling analysis. The NDDoH developed an hourly ammonia ba ckground concentration file to use with POSTUTIL repartitioning. To create the hourly file , observed hourly ammonia concentrations were obtained from the State’s Beulah monitoring si te (the only ammonia site in North Dakota) for the three-year period 2001-2003. Hourly data f or the three years were filtered to eliminate

data from wind directions associated with sources c ausing a local bias. Then the three years were averaged together, on a temporally consistent basis, to produce a single hourly file considered representative of 2002, and appropriate for use with 2002 meteorological data modeling. Years 2001 and 2003 were incorporated in an averaging scheme because year 2002 contained missing periods of hourly data, and some additional data were lost due to filtering as described above. Finally, smoothing was applied to the resultant hourly data set, in the form of a 24-hour running average, to dampen the effect of di scontinuities in the ammonia data.

The resultant background hourly ammonia file was te sted during the performance evaluation of the hybrid modeling system (Section 8.6.1). While the adjusted Beulah data provided good modeled comparisons with TRNP observed nitrate, the LWA nitrate observations were consistently under predicted. The NDDoH found that agreement with LWA nitrate observations was significantly improved if hourly values in the ammonia file are approximately doubled. Moreover, the NDDoH found empirical evidence (discu ssed below) that ammonia levels in the vicinity of LWA would be typically higher than ammo nia levels at TRNP. Therefore, the118

NDDoH applied the original hourly ammonia file (abo ve) for all POSTUTIL processing associated with TRNP, and doubled the hourly ammoni a profile for all POSTUTIL processing

associated with LWA.

In addition to performance evaluation results, ther e is empirical support for the assumption of higher ammonia background at LWA than at TRNP and B eulah. Figure 8.9 provides an illustration of ammonia emissions density (tons/yea r/square mile) for North Dakota counties and adjoining Canadian provinces. These data were obta ined from the WRAP RMC 2004/2005

report 40 , and represent ammonia input conditions for CMAQ m odeling. As shown in the figure, the TRNP and LWA IMPROVE sites, and the Beulah moni toring site, are all located in counties with the lowest ammonia emissions density (0.000-0. 001 tons/year/square mile). However, the proximity of the LWA site is such that prevailing l ocal winds (northwest and southeast wind direction) will likely direct higher density ammoni a emissions from Saskatchewan (0.075-0.25 tons/year/square mile) and Ward county (0.005-0.025 tons/year/square mile) toward the LWA

site.

For comparing predicted visibility progress with re spect to the default (EPA) glide path, the NDDoH applied the basic ammonia limiting method, pr esented as Step 1 in Table 8.7. In order to determine progress in the context of weight of e vidence arguments, such as discounting the effect of Canadian emissions, it was necessary to a pply the 3-step ammonia limiting method (Section 8.6.3).

POSTUTIL output was subsequently processed with the NDDoH CALHAZE program to project future visibility (Section 8.5.5).



### 8.5.5 CALHAZE

The NDDoH has developed a software system to genera te relative response factors (RRFs) from WRAP CMAQ and NDDoH CALPUFF (POSTUTIL) hourly conce ntration output files for baseline and future scenarios, project future conce ntrations of visibility affecting aerosols by applying RRFs to baseline IMPROVE data, and convert projected future concentrations to visibility (deciview). This system is informally k nown as CALHAZE. CALHAZE represents the final step in the NDDoH hybrid visibility model ing sequence (CALMET-CALPUFFPOSTUTIL-CALHAZE). Effectively, CALHAZE replaces C ALPOST.

CALHAZE accesses NDDoH CALPUFF (POSTUTIL) hourly co ncentration files for baseline and future scenarios to generate 20 percent worst/b est day RRFs for sulfate and nitrate. CALHAZE accesses WRAP CMAQ hourly concentration fil es (provided by WRAP RMC) for baseline and future scenarios to generate 20 percen t worst/best day RRFs for all other visibility

40 Tonnesen, G., R. Morris, Z. Adelman, et. al., 2005 . Final Report for the Western Regional Air Partnership (WRAP) Regional Modeling C enter (RMC) for the Project Period March 1, 2004, through February 28, 2005, Appendice s A Through E. Western Regional Air Partnership, Denver, CO 80202.119Figure 8.9NH3Emissions Density for North Dakota Counties and Adjoining Canadian Provinces*LWA IMPROVE SiteTRNPIMPROVE SiteBeulah Monitoring SiteSaskatchewanManitoba*From WRAP RMC 2004 reportWard120

affecting species. RRFs are applied to IMPROVE bas eline monitoring (2000-2004) data files, obtained from the WRAP TSS (Technical Support Syste m) internet site (http://vista.cira.colostate.edu/tss/ ), to project future concentrations of each visibil ity affecting species for each worst/best day for each year. Nex t, CALHAZE applies the new IMPROVE algorithm to calculate light extinction (using proj ected future concentrations) for each worst/best day for each year. Finally, deciview is calculated for each worst/best day, and averaged across all worst/best days and all years. CALHAZE repeats this procedure for each Class I area. CALHAZE incorporates the default EPA methodology to calculate RRFs and future deciview (Section 8.3).

Input files required by CALHAZE, as applied by NDDo H, are summarized:

1) WRAP CMAQ hourly concentration output file for base line scenario (2002),

2) WRAP CMAQ hourly concentration output file for futu re scenario (2018),

3) NDDoH CALPUFF (POSTUTIL) hourly concentration outpu t file for baseline scenario (2002 results for both TRNP and LWA receptors),

4) NDDoH CALPUFF (POSTUTIL) hourly concentration outpu t file for future scenario (2018 results for both TRNP and LWA receptors),

5) IMPROVE daily baseline monitoring data for TRNP (20 00-2004),

6) IMPROVE daily baseline monitoring data for LWA (200 0-2004).

CMAQ hourly concentrations are taken from the grid cell containing the North Dakota Class I area. Note that all additional parameters necessar y for calculating light extinction, via the new IMPROVE algorithm, are provided in the IMPROVE base line monitoring data files. This includes function of relative humidity for sea salt and small and large size fractions, and the Rayleigh scattering coefficient. Consistent with W RAP RMC conclusions addressing the viability of CMAQ coarse mass predictions, CALHAZE forces a RRF of 1.0 for the coarse mass species. As discussed in Section 8.2, a constant R RF of 1.0 is also applied for sea salt.

As an option, the CALHAZE system also accepts a con trol input file which allows the user to set RRF for each species, and set the visibility target (in deciviews), for each Class I area. Use of this feature was necessary when applying the normal ization procedure described in Section 8.5.6.

The NDDoH has applied the CALHAZE software to compl ete the hybrid modeling procedure and visibility projections for North Dakota Class I areas. To address quality assurance issues with respect to the CALHAZE system, the NDDoH has s uccessfully cross-checked CALHAZE output with data on the TSS internet site. For exa mple, the worst-day RRFs generated by CALHAZE for elemental carbon, organic mass, fine so il, and coarse mass for North Dakota Class I areas agree exactly with the corresponding values obtained from the TSS site.121



### 8.5.6 Hybrid System Used to Adjust WRAP CMAQ Mo deling Results

Based on performance testing of direct hybrid model predictions (operational evaluation), as conducted by NDDoH (see Section 8.6.1), the hybrid CMAQ-CALPUFF modeling system performed well in replicating observed concentratio ns of SO 4 and NO 3 . However, performance regarding sensitivity to changes in NO X emissions (diagnostic evaluation) was not good, wi th the hybrid modeling system significantly overstating fu ture case nitrate formation compared to predictions obtained by WRAP using CMAQ alone. The NDDoH concluded this anomaly is an artifact of the chemistry in CALPUFF, and acknowled ges that CMAQ chemistry is superior.

For this reason, the NDDoH chose not to accept dire ct hybrid modeling system results to independently address progress with respect to regi onal haze goals. Rather, the NDDoH used the hybrid modeling system in a supportive sense to add value to the original WRAP CMAQ modeling results. The hybrid system was used to pr ovide a “correction” to WRAP CMAQ results in order to offset coarseness in the CMAQ s patial resolution for large, local point sources. Similarly, the hybrid system was applied to adjust WRAP CMAQ results in order to discount the effect of international (Canadian) sources. (WRAP did not provide regional haze modeling results which discount the impact of international sources, a modeling interpretation which had been requested by EPA and others, and which the NDD oH wanted to include in its weight of evidence discussion.)



### 8.5.6.1 Adjusting WRAP CMAQ Modeling Results fo r Local Point Sources

To address the concern regarding spatial resolution of the WRAP CMAQ simulations for local point sources, the NDDoH concluded that the hybrid modeling system could be used in an indirect manner to apply a reasonable and conceptua lly simple “correction” to the WRAP CMAQ RRFs (relative response factors) for sulfate a nd nitrate. Given that CALPUFF has the capability of treating point sources as well as are a sources, all point sources within the NDDoH CALPUFF domain can be allocated (converted) to area sources, or more specifically to a 36-km area source grid, in order to emulate the coarse tr eatment of point sources in CMAQ. Then a correction factor can be established which adjusts the WRAP CMAQ prediction based on the predicted difference between point sources treated as conventional point sources and point sources treated as area sources (i.e., CMAQ emulati on) with the hybrid model. This adjustment can be expressed

      


 
	  8  1

where

  is the adjusted average concentration (sulfate or nitrate) for 20% worst days. Note that both WRAP and NDDoH were consistent in basing 20% worst days on IMPROVE monitoring data (2002),122

  is the average concentration for 20% worst days ob tained by WRAP using

CMAQ,

 
 is the average concentration for 20% worst days pr edicted by the hybrid

model when point sources (within the NDDoH CALPUFF domain) are treated as conventional point sources,

 
	 is the average concentration for 20% worst days pr edicted by the hybrid

model when point sources (within the NDDoH CALPUFF domain) are allocated as

36-km area sources.

The ratio  
 /  
	 in the equation is effectively a correction factor to address the

coarse resolution of local point sources in CMAQ. Equation 8-1 can be thought of as an emulation of the result CMAQ would have produced ha d the plume-in-grid feature been deployed for local point sources (WRAP did not depl oy CMAQ plume-in-grid for regional haze modeling). The Equation 8-1 adjustment involves mo difying only the point source component of the hybrid model emissions inventory. Boundary con ditions and sources originally treated as area sources (Section 8.5.3.1) remain equivalent in HybridPt and HybridArea emissions

inventories.

Equation 8-1 is applicable for both baseline and fu ture period modeling. Recall that the RRF for each species is defined 41

,    

  !" 

where   is the future 20% worst day average concentration and   !" is the baseline
20% worst day average concentration. Therefore, if the future period implementation of Equation 8-1 is divided by the baseline period impl ementation of Equation 8-1, it follows that the adjustment for CMAQ treatment of point sources can be specified in terms of RRF,

  

 




 
	  8  2

where



 is the adjusted relative response factor ultimatel y used by NDDoH to project future concentrations of sulfate and nitrate,

  is the relative response factor obtained by WRAP u sing CMAQ,

41 See supra note 7.123

 
 is the relative response factor produced by the hy brid model when point
sources (within NDDoH CALPUFF domain) are treated as conventional point sources,

 
	 is the relative response factor produced by the hy brid model when point
sources (within NDDoH CALPUFF domain) are allocate d as 36-km area sources.

Thus, Equation 8-2 was used by NDDoH to implement t he adjustment for WRAP CMAQ treatment of point sources. The adjustment was uti lized for 20% best days as well as 20% worst days, and was applied for each Class I area in Nort h Dakota. It was applied directly to the RRFs from WRAP CMAQ modeling (specific day option 42 ), which are shown in Table 8.8.



### Table 8.8 WRAP CMAQ RRF (Specific Day Option)

TRNP Worst Day TRNP

Best Day LWA

Worst Day LWA

Best Day

SO 4 0.92 1.02 0.91 1.02

NO 3 0.92 0.93 0.96 0.89

OMC 1.01 1.01 1.05 1.01

EC 0.72 0.78 0.73 0.74

Soil 1.13 1.08 1.11 0.96

CM 1.00 1.00 1.00 1.00

To develop the HybridArea CALPUFF input files, all point source emissions we re allocated to the CALPUFF 36-km area source grid, which is discus sed in Section 8.5.3.1 and shown in Figure 8.8. The CALPUFF “effective height” (plume height) and “initial sigma z” area source input parameters were used to assign point source e missions to discrete vertical “layers” which are consistent with the WRAP CMAQ layers. Effectiv e height is based on stack height plus plume rise as calculated externally.

42 In addition to the EPA-recommended specific day op tion for generating RRFs, WRAP also generated RRFs and projected future visibility based on monthly and quarterly weighting. The NDDoH used the specific day option exclusively in hybrid visibility modeling.124

To complete emulation of the WRAP CMAQ 36-km grid r esolution, receptor treatment was also

addressed in the HybridArea input files. Effective “receptor” resolution in W RAP CMAQ is limited to the average concentration in the 36-km s urface grid cell volume containing the Class I area IMPROVE site. To emulate WRAP CMAQ in HybridArea input files, the NDDoH averaged across a uniform receptor grid which fille d the CALPUFF area-source 36-km grid cell containing each IMPROVE site (Figure 8.8). Recepto rs were spaced at 3 km for a total of 12 x 12 or 144 discrete receptors for each Class I area. Note that this type of receptor averaging was only applied in CALPUFF runs for CMAQ emulation ( HybridArea ), and not in runs for conventional point source treatment ( HybridPt ) or performance evaluation.

Given that the NDDoH hybrid modeling was limited to sulfate and nitrate species (and precursors), the Equation 8.2 adjustment was also l imited to sulfate and nitrate species. The RRFs for all other light affecting species were tak en directly from WRAP CMAQ modeling, as shown in Table 8.8. Therefore, it is likely that t he correction for CMAQ resolution of point sources, in terms of the total projected future lig ht extinction, is somewhat understated. However, the primary contributors to light extincti on from the local point sources of concern in

North Dakota are sulfate and nitrate.

The Equation 8.2 adjustment as applied by NDDoH als o accounted for the WRAP overestimate of future oil and gas related NO X emissions in North Dakota, as discussed in Section 8.5.3.1. This error affected the future period modeling only . Therefore, the HybridArea input file (CMAQ emulation) for the future period included WRA P estimated NO X emissions for oil and gas, while the HybridPt

input file for the future period included the NDDo H corrected future

NO X emissions for oil and gas. (The base period NO X emissions in both cases were based on WRAP estimates for 2002.) This accounting for the WRAP error in future oil and gas NO X emissions was not expected to make a significant di fference in results.

When applying the Equation 8.2 adjustment, the NDDo H found the ratio  
 to

 
	 to be consistently less than 1.0, providing a resu ltant  which was significantly lower than the WRAP CMAQ RRF, with su bsequently lower projected future concentrations and greater projected visibility imp rovement than predicted by WRAP. This expected response is related primarily to the resol ution of modeling systems as applied to local point sources. When local point sources are treate d as conventional point sources, the higher density point-source plumes cause higher prediction s at the IMPROVE monitor site (for both baseline and future periods) such that the future r eduction in emissions from local point sources may cause a relatively large impact compared to the more static contribution of all other sources (area and boundary). When local point sources are configured as 36-km area sources, the associated diluted plumes cause lower predictions c ompared to the contribution of all other sources (other area and boundary), such that the fu ture reduction in emissions may be overwhelmed by the more static contribution of othe r sources.



### 8.5.6.2 Discounting the Impact of Canadian Sour ces

In the process of analyzing progress with respect t o visibility goals, it was necessary for the NDDoH to address the impact of Canadian sources nor th of the International border. This125

interpretation of modeling results was requested by EPA and others, and was an important element of the NDDoH weight of evidence discussion (see Section 8.6.3). No specific guidance is provided for this type of analysis. The method used by NDDoH was to eliminate Canadian

sources from the baseline and future emissions inve ntories used to develop RRFs, and to develop a modified glide path which discounts the effect of Canadian sources. This approach is similar to methods proposed by CENRAP 43 and others.

Again, the NDDoH implemented its procedure for disc ounting Canadian sources in terms of an adjustment to WRAP CMAQ modeling results. If Canad ian sources are eliminated from

baseline and future emissions inventories for conve ntional point sources, Equation 8-2 becomes

  

 


$

 
	  8  3

where




$ represents the resultant relative response factor after eliminating Canadian sources from the conventional point sourc e baseline and future emissions inventories used with the hybrid modeling system.

Equation 8-3 was used by the NDDoH to develop adjus ted RRFs for sulfate and nitrate. Note that with the implementation of Equation 8-3, the a djustment to discount the impact of Canadian sources is effectively “added on” to the adjustment for WRAP CMAQ point source resolution.

To complete the illustration, the impact of Canadia n sources must also be discounted from the glide path used to assess progress with respect to visibility goals. In this case, the NDDoH applied the hybrid modeling system exclusively to e stimate the baseline starting point (deciview) of the modified glide path. The estimation process involved adjusting the IMPROVE baseline concentration for each worst-case day for the five- year period 2000-2004, in order to approximate the daily observations without the impa ct of Canadian sources. The estimation procedure for each worst-case day can be expressed

 &
     &  ' 

 '  8  4

where

 &
   is the estimated sulfate or nitrate concentration for one worst case day of
IMPROVE monitoring data for all non-Canadian sourc es (plus natural background),

43 CENRAP, 2007. CENRAP Policy Oversight Group (POG) - Summary of PM Source Apportionment Modeling and 2018 Projection Approach es. Power Point presentation, Joint Workgroup Meeting, Kansas City, Missouri, March 7, 2007.126

 & is the original IMPROVE observed sulfate or nitrat e concentration for the worst case day,

 '    is the average prediction for 20% worst days when hybrid model is applied

for non-Canadian sources only (Year 2002 baseline emissions inventory),

 ' is the average prediction for 20% worst days when hybrid model is applied for

the entire source inventory (Year 2002 baseline em issions inventory).

Using the adjusted worst day observations for sulfa te and nitrate, along with the original IMPROVE worst day observations for all other visibi lity-affecting species, light extinction and deciview were calculated for each 20% worst day of the 2000-2004 period. Finally, the five-year average deciview was calculated to set the starting point for the “Canadian sources discounted” glide path for 20% worst days.

The NDDoH next considered the end point (2064) of t he modified glide path. When adjusting

baseline and future emissions inventories to exclud e Canadian sources, the intent of NDDoH was to eliminate the impact of non-natural sources only , leaving the contribution of all other nonCanadian sources plus natural sources. Therefore, an adjustment was made to CALPUFF boundary conditions (baseline and future) to elimin ate the contribution of Canadian source emissions, while retaining the impact of natural Ca nadian sources of sulfate and nitrate. This adjustment is described in Section 8.6.3.1. And re call that the NDDoH adjustment does not affect the impact of all other visibility-affecting species on the glide path. As such, the NDDoH concluded that it was not necessary or appropriate to change the end point (default natural conditions) of the modified glide path.

A modified glide path is illustrated in Figure 8.10 , for a hypothetical case where Canadian source

emissions contribute about one-half of total visibi lity degradation.

Using the modified glide path, the NDDoH applied RR Fs generated using Equation 8-3 to the adjusted starting point to estimate visibility impr ovement progress by 2018 (see Section 8.6.3.1). As expected, visibility improvement increased signi ficantly when Canadian sources were

discounted. Canadian source emissions were discoun ted only for 20% worst days, as the impact of Canadian sources was not problematic in meeting visibility goals for best days.127Figure 8.10Illustration of Visibility Improvement Using EPA Default Glide Pathand Canadian Sources Discounted Glide Path2004 2024 2044 2064Year04812162024

D e c i v i e w E P A D e f a u l t G l i d e P a t h

C a n a d i a n S o u r c e s D i s c o u n t e d G l i d e P a t h2018 Projection -61% of goal achieved2018 Projection -124% of goal achieved128



### 8.6 Modeling Process and Results

The NDDoH hybrid modeling system was applied to adj ust WRAP CMAQ results, using input conditions and procedures as described in Section 8 .5. A performance evaluation was conducted first to ensure that selected inputs were producing viable results relative to observed concentrations of sulfate and nitrate. (Note that the performance evaluation was based on predictions taken directly from hybrid model output , rather than adjusted WRAP CMAQ output described in Section 8.5.6.) Next, the hybrid model ing system was executed in default production mode to determine progress with respect to the glide path and URP target based on default EPA methodology. Finally, the hybrid model ing system was applied to test several weight of evidence scenarios. NDDoH hybrid results and WRAP CMAQ results were compared for the default EPA methodology.



### 8.6.1 Hybrid CMAQ-CALPUFF Performance Evaluatio n

The NDDoH conducted a limited operational evaluatio n to assess performance of the hybrid CMAQ-CALPUFF modeling system. The focus of the eva luation was to assess performance in reproducing observed concentrations of sulfate and nitrate at IMPROVE monitoring sites in

North Dakota. These sites include the Theodore Roo sevelt National Park South Unit (TRNP) and the Lostwood Wilderness Area (LWA). Alternativ e input options which might improve performance were also explored. To the extent appl icable, the performance evaluation followed EPA guidance for Regional Haze modeling analyses 44

.

An emissions inventory for the performance evaluati on was developed by NDDoH. WRAP CMAQ hourly concentration output (SO 2 -SO 4 -NO X -HNO 3 -NO 3 ) for Case BASE02B was used to set hourly boundary conditions for CALPUFF. The emissions inventory (SO 2 -NO X ) for the point source category was developed using data from the NDDoH emissions database for 2002, and sources were configured as conventional point s ources in CALPUFF. This inventory included point sources located in adjacent parts of South Dakota, Montana, and Canada, which are included in the NDDoH CALPUFF domain (see Figur e 8.5). This inventory also included

SO 2 emissions associated with oil and gas production f acilities (treaters and flares) in North Dakota, which did not appear to be accounted for in the WRAP inventory for BASE02B. Emission rates for the point source inventory refle ct actual emissions for Year 2002.

All other source categories (see Table 8.2) were tr eated as area sources in CALPUFF, and the emissions inventory (SO 2 -SO 4 -NO X -NO 3 ) for these categories was based on WRAP CMAQ input (SMOKE output) for all sources other than poi nt sources. Software was prepared and implemented to apportion the gridded SMOKE output e missions for BASE02B into a 36-km area source grid structure developed for the NDDoH CALPUFF domain (Figure 8.8), on a consistent spatial basis. Emission rates for this area source inventory reflect annual averages for

the SMOKE data.

44 See supra note 7.129

The CALPUFF modeling system (CALMET-CALPUFF-POSTUTI L-CALPOST) was applied

for SO 2 -SO 4 -NO X -NO 3 source inventories and boundary conditions as desc ribed above. All other input conditions were consistent with the des cription of the hybrid modeling system in Section 8.5. Single receptors were placed at the T RNP and LWA IMPROVE sites. Monthly average ammonia data were utilized from the Beulah monitoring site in both CALPUFF and

POSTUTIL.

After initial application of CALPUFF for the perfor mance evaluation, it was concluded that certain scientifically-defensible adjustments to CA LPUFF input conditions may improve performance for the hybrid modeling system, and sho uld be investigated. Thus, the performance

evaluation evolved into a suite of tests which are described below.

1) Test 1 - Calpuff executed with default input condit ions, as outlined above. Air mass depth for boundary conditions was set to 2000 meters.

2) Test 2 - CALPUFF as in Test 1, but using CEMS 2002 hourly emissions data (SO 2 , NO X ) for point sources, where available.

3) Test 3 - CALPUFF as in Test 1, but using WRAP MM5 1 2 km 2002 mesoscale data in CALMET, rather than the default NDDoH RUC 2002 meso scale data.

4) Test 4 - CALPUFF as in Test 1, but increasing air m ass depth for boundary conditions from

2000 to 3000 meters.

5) Test 5 - CALPUFF as in Test 1, but with addition of SO 4 and NO 3 emissions from point sources. (Previous tests excluded this component, because SO 4 and NO 3 emissions are not included in the NDDoH point source inventory. For Test 5, an SO 4 -NO 3 emissions inventory was derived from SMOKE gridded output for the point source category, and configured as area sources for CALPUFF.)

6) Test 6 - CALPUFF as in Tests 4 and 5 (air mass dept h = 3000 meters, SO 4 and NO 3 emissions from point sources included), but area so urces configured as 4 separate groups to account for varying release heights of different so urce types, and Beulah hourly profile used for background NH 3 in POSTUTIL. (Area sources were configured as a s ingle CALPUFF group in previous tests.)

7) Test 7 - CALPUFF as in Test 6, but Beulah hourly NH 3 profile doubled for LWA.

Results of the performance evaluation are summarize d in Tables 8.9 and 8.10. Table 8.9 compares predicted NO 3 and SO 4 concentrations to observed concentrations for both IMPROVE sites, while Table 8.10 provides predicted-to-obser ved ratios. Note that both tables include a column labeled “CMAQ only”, which provides the orig inal WRAP CMAQ results for Case

BASE02B.130Table 8.9Hybrid CMAQ-CALPUFF Performance EvaluationObserved and Predicted Concentrations Year 2002 (ug/m3)Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7TRSU NO398th Percentile Day2.032.11 2.11 2.20 1.96 2.11 2.06 2.06 3.2190th Percentile Day1.211.50 1.46 1.55 1.43 1.47 1.21 1.21 1.62Avg 20% Worst Days1.421.59 1.59 1.65 1.56 1.59 1.41 1.41 1.84Annual Average0.500.71 0.71 0.73 0.70 0.71 0.53 0.53 0.57TRSU SO498th Percentile Day3.292.57 2.57 2.47 2.53 2.57 2.58 2.58 2.3690th Percentile Day1.881.72 1.72 1.66 1.77 1.72 1.79 1.79 1.60Avg 20% Worst Days2.431.96 1.97 1.83 1.96 1.98 1.99 1.99 1.76Annual Average1.030.90 0.90 0.86 0.90 0.91 0.91 0.91 0.84Lostwood NO398th Percentile Day3.651.91 1.91 2.01 1.94 1.85 2.15 2.74 3.6490th Percentile Day1.951.48 1.50 1.56 1.47 1.44 1.13 1.76 2.04Avg 20% Worst Days2.331.55 1.55 1.61 1.52 1.50 1.30 2.03 2.34Annual Average0.790.70 0.70 0.73 0.69 0.67 0.47 0.80 0.79Lostwood SO498th Percentile Day3.102.91 2.90 2.74 2.88 3.11 3.12 3.12 3.6590th Percentile Day2.222.06 2.03 1.90 2.07 2.19 2.21 2.21 2.43Avg 20% Worst Days2.492.21 2.21 2.09 2.22 2.35 2.36 2.36 2.74Annual Average1.181.07 1.07 1.03 1.08 1.15 1.17 1.17 1.32* Test 1 - Calpuff run with default BART screeningprotocol + full emissions inventory + boundary conditionsTest 2 - Calpuff as in Test 1 but using CEMS hrly emissions (SO2, NOX) where availableTest 3 - Calpuff as in Test 1 but using WRAP MM512km mesoscale data (in CALMET)Test 4 - Calpuff as in Test 1 but assuming boundary air mass depth as 3000 m rather than 2000 mTest 5 - Calpuff as in Test 1 but with additionof NO3 and SO4 emissions from point sourcesTest 6 - Calpuff as in Test 1 but assuming boundary air mass depth as 3000 m (Test 4) and withaddition of NO3 and SO4 emissions from point sources (Test 5). Area sources configuredas 4 groups and Beulah hourly profile used for backgound NH3.Test 7 - Calpuff as in Test 6 but Beulah hourlyNH3 profile doubled for LostwoodObservedCMAQonlyHybrid CMAQ-CALPUFF Predicted*131Table 8.10Hybrid CMAQ-CALPUFF Performance EvaluationPredicted to Observed Ratios 2002Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7TRSU NO398th Percentile Day 1.04 1.04 1.08 0.97 1.04 1.01 1.011.5890th Percentile Day 1.24 1.21 1.28 1.18 1.21 1.00 1.001.34Avg 20% Worst Days 1.12 1.12 1.16 1.10 1.12 0.99 0.99 1.30Annual Average 1.42 1.42 1.46 1.40 1.42 1.06 1.06 1.14TRSU SO498th Percentile Day 0.78 0.78 0.75 0.77 0.78 0.78 0.780.7290th Percentile Day 0.91 0.91 0.88 0.94 0.91 0.95 0.950.85Avg 20% Worst Days 0.81 0.81 0.75 0.81 0.81 0.82 0.82 0.72Annual Average 0.87 0.87 0.83 0.87 0.88 0.88 0.88 0.82Lostwood NO398th Percentile Day 0.52 0.52 0.55 0.53 0.51 0.59 0.751.0090th Percentile Day 0.76 0.77 0.80 0.75 0.74 0.58 0.901.05Avg 20% Worst Days 0.67 0.67 0.69 0.65 0.64 0.56 0.87 1.00Annual Average 0.89 0.89 0.92 0.87 0.85 0.59 1.01 1.00Lostwood SO498th Percentile Day 0.94 0.94 0.88 0.93 1.00 1.01 1.011.1890th Percentile Day 0.93 0.91 0.86 0.93 0.99 1.00 1.001.09Avg 20% Worst Days 0.89 0.89 0.84 0.89 0.94 0.95 0.95 1.10Annual Average 0.91 0.91 0.87 0.92 0.97 0.99 0.99 1.12* Test 1 - Calpuff run with default BART screeningprotocol + full emissions inventory + boundary conditionsTest 2 - Calpuff as in Test 1 but using CEMS hrly emissions (SO2, NOX) where availableTest 3 - Calpuff as in Test 1 but using WRAP MM512km mesoscale data (in CALMET)Test 4 - Calpuff as in Test 1 but assuming boundary air mass depth as 3000 m rather than 2000 mTest 5 - Calpuff as in Test 1 but with additionof NO3 and SO4 emissions from point sourcesTest 6 - Calpuff as in Test 1 but assuming boundary air mass depth as 3000 m (Test 4) and withaddition of NO3 and SO4 emissions from point sources (Test 5). Area sources configuredas 4 groups and Beulah hourly profile used for backgound NH3.Test 7 - Calpuff as in Test 6 but Beulah hourlyNH3 profile doubled for LostwoodCMAQonlyHybrid CMAQ-CALPUFF*Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7TRSU NO398th Percentile Day 1.04 1.04 1.08 0.97 1.04 1.01 1.011.5890th Percentile Day 1.24 1.21 1.28 1.18 1.21 1.00 1.001.34Avg 20% Worst Days 1.12 1.12 1.16 1.10 1.12 0.99 0.99 1.30Annual Average 1.42 1.42 1.46 1.40 1.42 1.06 1.06 1.14TRSU SO498th Percentile Day 0.78 0.78 0.75 0.77 0.78 0.78 0.780.7290th Percentile Day 0.91 0.91 0.88 0.94 0.91 0.95 0.950.85Avg 20% Worst Days 0.81 0.81 0.75 0.81 0.81 0.82 0.82 0.72Annual Average 0.87 0.87 0.83 0.87 0.88 0.88 0.88 0.82Lostwood NO398th Percentile Day 0.52 0.52 0.55 0.53 0.51 0.59 0.751.0090th Percentile Day 0.76 0.77 0.80 0.75 0.74 0.58 0.901.05Avg 20% Worst Days 0.67 0.67 0.69 0.65 0.64 0.56 0.87 1.00Annual Average 0.89 0.89 0.92 0.87 0.85 0.59 1.01 1.00Lostwood SO498th Percentile Day 0.94 0.94 0.88 0.93 1.00 1.01 1.011.1890th Percentile Day 0.93 0.91 0.86 0.93 0.99 1.00 1.001.09Avg 20% Worst Days 0.89 0.89 0.84 0.89 0.94 0.95 0.95 1.10Annual Average 0.91 0.91 0.87 0.92 0.97 0.99 0.99 1.12* Test 1 - Calpuff run with default BART screeningprotocol + full emissions inventory + boundary conditionsTest 2 - Calpuff as in Test 1 but using CEMS hrly emissions (SO2, NOX) where availableTest 3 - Calpuff as in Test 1 but using WRAP MM512km mesoscale data (in CALMET)Test 4 - Calpuff as in Test 1 but assuming boundary air mass depth as 3000 m rather than 2000 mTest 5 - Calpuff as in Test 1 but with additionof NO3 and SO4 emissions from point sourcesTest 6 - Calpuff as in Test 1 but assuming boundary air mass depth as 3000 m (Test 4) and withaddition of NO3 and SO4 emissions from point sources (Test 5). Area sources configuredas 4 groups and Beulah hourly profile used for backgound NH3.Test 7 - Calpuff as in Test 6 but Beulah hourlyNH3 profile doubled for LostwoodCMAQonlyHybrid CMAQ-CALPUFF*132

As shown in Tables 8.9 and 8.10, the primary metric s selected to measure performance for this

evaluation are 90 th percentile day concentration (24-hour average), av erage of 20% worst days concentration, and annual average concentration. T he first two metrics were selected for consistency with the time scale that applies to reg ional haze modeling, i.e., average of the 20% worst or 20% best days. The third metric, annual a verage concentration, is a measure of the model’s ability to accurately conserve total annual mass. The comparison between predicted and

observed concentrations for the first two metrics i s unpaired in time.

Also shown in Tables 8.9 and 8.10 is the 98 th percentile day prediction (24-hour average). This metric was included for completeness at the request of EPA. The 98 th percentile prediction has relevance as the primary metric used in BART single -source modeling.

Results in Tables 8.9 and 8.10 indicate that the hy brid modeling system performed well, in general. Even for the initial Test 1, predictions were well within a factor of two of observations. In most cases, the hybrid system predictions were c loser to observations than predictions from CMAQ, alone. Table 8.10 illustrates that the hybri d system slightly over-predicted observations

for TRNP NO 3 , and slightly under-predicted, otherwise.

A comparison of results for Tests 1 through 5 revea ls very little difference in predictions. The implication is that the input changes reflected in Tests 2 through 5 did not add significant value to the hybrid model’s ability to accurately reprodu ce observations. The increased temporal resolution obtained by using the CEMS hourly emissi ons for applicable point sources (Test 2) provided no consistent improvement. Test 3 results suggest that the NDDoH RUC mesoscale

data is consistent with the WRAP MM5 mesoscale data . Test 4 results indicate that Calpuff is not very sensitive to boundary air mass depth. Eve n the addition of point source NO 3 and SO 4 emissions in Test 5 achieved no meaningful improvem ent in predictions, suggesting that sources configured as area sources in CALPUFF may have only a small contribution to the total prediction.

While the operational evaluation to compare predict ions with observations was being conducted, the NDDoH also undertook a preliminary diagnostic e valuation 45 to assess the response of the hybrid modeling system to changes in NO X and SO 2 emissions. In response to significant

reductions in both SO 2 and NO X emissions, the NDDoH found that the hybrid system responded reasonably well with correspondingly lower SO 4 predictions, but seemed to overstate NO 3 predictions for the reduced emission scenario. In fact, NO 3 concentrations actually increased under some assumptions, possibly an overreaction to the newly freed ammonia in the reduced

SO 2 emissions scenario (SO 2 preferentially scavenges ammonia in the CALPUFF ch emistry). This behavior was not as obvious in the WRAP CMAQ r esults for baseline versus future predictions.

45 See supra note 7.133

To address the problematic NO 3 response, the NDDoH discussed the issue with Joe S cire (TRC) 46 , a recognized CALPUFF expert in the regulatory mod eling community. Mr. Scire indicated that TRC testing has shown that the NO 3 response may improve if hourly background ammonia is used rather than monthly average values. Also, Mr. Scire provided some insight on configuring area sources in CALPUFF to be more cons istent with the area source treatment in CMAQ. This involves proper settings for the CALPUF F “release height” and “initial sigma z” input parameters for area sources. The NDDoH retes ted after incorporating Mr. Scire’s suggestions, i.e., using hourly ammonia background and reconfigured area sources. Although

the NO 3 response improved, predicted reductions were still not consistent with CMAQ.

As a result of the initial diagnostic performance t esting, the NDDoH concluded that the use of hourly ammonia background concentrations is prefera ble to the use of monthly averages, and that CALPUFF inputs for area sources should be reco nfigured. Additional operational evaluation tests (Tests 6 and 7) were thus conducte d to determine how these changes would affect the comparison with observations. Test 6 wa s conducted by first assuming a boundary air mass depth of 3000 meters (Test 4) and accounting f or NO 3 and SO 4 emissions from point sources (Test 5). Then area sources were configure d as suggested by Scire, including the use of 4 area source groups to account for varying release heights for different source categories (as opposed to one group in Tests 1-5). Finally, Test 6 included use of the Beulah hourly ammonia profile in POSTUTIL.

Results of Test 6, as shown in Tables 8.9 and 8.10, indicate significantly improved performance with respect to TRNP NO 3 , but worse performance for LWA NO 3 . Results for SO 4 were not significantly affected. This tendency for conflict ing results for TRNP and LWA NO 3 was also exhibited in Tests 1 through 5, and led the NDDoH t o conclude that the Beulah data may not be representative of ammonia background for both TRNP and LWA. Moreover, the actual ammonia background affecting LWA may be significant ly higher than the background affecting

TRNP.

In Test 7, the NDDoH found that observational agree ment for LWA NO 3 can be vastly improved if the ammonia hourly backgound values are approxim ately doubled (for LWA only). All other conditions for Test 7, including the ammonia backgr ound for TRNP, remain the same as in Test

6. NO 3 predictions for Test 7 in Tables 8.9 and 8.10 now show good agreement with

observations at both TRNP and LWA.

Finally, the NDDoH developed time series plots (con sistent with Test 1 assumptions) to compare temporal patterns of predictions with observations for year 2002. In Figure 8.11, daily model predictions for nitrate at TRNP are compared with I MPROVE observations for 2002 (note that observations are only available for every third day ). Time series for both NDDoH hybrid predictions and WRAP CMAQ predictions are included. As shown in the figure, both modeling systems appear to reproduce the general seasonal pa ttern of nitrate observations, with significantly lower concentrations in the summer. When compared with observations, the overall magnitude of predictions for the hybrid modeling sy stem appears better, as CMAQ seems to under predict in the summer (many daily values very close to 0.0) and over predict otherwise.

46 See supra note 28.134 

### Figure 8.11

Observed and Predicted Time Series TRNP NO 3 

### 2002

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0Conc. (ug/m3) IMPROVE Observed

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0Conc. (ug/m3) NDDoH Hybrid Predicted

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.001/02/0201/16/0201/30/0202/13/0202/27/0203/13/0203/27/0204/10/0204/24/0205/08/0205/22/0206/05/0206/19/0207/03/0207/17/0207/31/0208/14/0208/28/0209/11/0209/25/0210/09/0210/23/0211/06/0211/20/0212/04/0212/18/02Conc. (ug/m3)

Date WRAP CMAQ Predicted135

CMAQ, however, may be more effective in reproducing some of the peak observed concentrations (paired in time).

In summary, the NDDoH concluded that the hybrid mod eling system performs effectively, and may be used to adjust WRAP CMAQ modeling results. Further, agreement with sulfate and nitrate observations would be optimized using the f ollowing input conditions with the hybrid

system:

• use RUC mesoscale data for CALMET,

• use boundary air mass depth of 3000 meters,

• include SO 4 and NO 3 emissions from point sources,

• configure area sources as four groups,

• use Beulah hourly background ammonia for TRNP, and

• use double Beulah hourly background ammonia for LWA

.



### 8.6.2 Results for Default EPA Methodology

8.6.2.1 Cumulative Results

The NDDoH hybrid modeling system was applied to adj ust WRAP CMAQ results, using input conditions and procedures consistent with optimal m odel performance, and described in Section 8.5. Hybrid modeling for the default EPA methodolo gy included the entire emissions inventory. NDDoH projections for 2018 visibility are compared here with WRAP RMC projections for 2018 visibility, based on default EPA methodology.

Results of WRAP CMAQ and NDDoH hybrid visibility mo deling for the default EPA scenario

are summarized in Table 8.11. The table includes v isibility projections for North Dakota Class I areas for 20% worst monitored days and 20% best mon itored days. The table includes deciview values for baseline conditions, natural conditions, and the 2018 uniform rate of progress (URP) target. WRAP and NDDoH projections provided in the table include the absolute visibility projection in deciviews, and the percentage of the visibility target achieved by the projection. Note that the URP target and projected percentage o f target are not included for best days, because the Regional Haze Rule specifies the URP ta rget only for worst days. The requirement for best days is simply that the visibility project ion for 2018 is no higher than the baseline

monitored value.136Table 8.11WRAP and NDDoH Visibility Modeling ResultsUniform Rate of Progress – Default EPA MethodologyClass IArea20%Worst/BestDays2000-2004BaselineConditions(dv)2064NaturalConditions(dv)2018URPTarget(dv)WRAP2018ProjectedVisibility(dv)WRAP2018ProjectedPercent ofTargetNDDoH2018ProjectedVisibility(dv)NDDoH2018ProjectedPercent ofTargetTheodoreRooseveltNational ParkWorst 17.80 7.8 15.47 17.24 24.0 16.91 38.1Best 7.76 3.04 ----- 7.67 ----- 7.62 -----LostwoodWildernessAreaWorst 19.57 8.0 16.87 19.12 16.7 18.85 26.7Best 8.19 2.92 ----- 8.06 ----- 8.10 -----137Figure 8.12TRNP Uniform Rate of Progress – EPA Default Methodology2004 2024 2044 2064Year681012141618

D e c i v i e wPredicted Progress to 2018WRAP - 1NDDH - 2

A l l S o u r c e s G l i d e P a t h122018138Figure 8.13LWA Uniform Rate of Progress – EPA Default Methodology2004 2024 2044 2064Year68101214161820

D e c i v i e wPredicted Progress to 2018WRAP - 1NDDH - 2

A l l S o u r c e s G l i d e P a t h122018139

As shown in Table 8.11, the NDDoH projections for 2 0% worst days indicate greater progress with respect to the 2018 goals than the WRAP projec tions, but both sets of projections fall well short of the URP targets. The WRAP projection cons titutes 24.0 percent of the visibility goal at Theodore Roosevelt National Park (TRNP), while the NDDoH projection is 37.1 percent of the goal at that Class I area. For Lostwood Wilderness Area (LWA), WRAP projects 16.7 percent of the URP goal while the NDDoH projects that 26.3 per cent of the goal will be achieved.

On the 20% best monitored days, both WRAP and NDDoH predictions in Table 8.11 illustrate that 2018 visibility will be better than baseline m onitored values for both TRNP and LWA Class I areas. The WRAP 2018 projection of 7.67 deciview s and the NDDoH 2018 projection of 7.63 deciviews compare favorably with the baseline value of 7.76 deciviews for TRNP. At the LWA Class I area, the WRAP 2018 prediction of 8.06 deci views and the NDDoH prediction of 8.10

deciviews both fall below the baseline value of 8.1 9 deciviews. Thus, requirements of the Regional Haze rule for the 20% best days will be sa tisfied.

Worst-day results of WRAP and NDDoH visibility mode ling for the EPA default scenario are graphically interpreted with respect to the uniform rate of progress in Figure 8.12 and Figure 8.13 for TRNP and LWA, respectively. The “all sour ces” glide paths in Figures 8.12 and 8.13 originate with the monitored baseline deciview valu e in 2004, and terminate with the natural background deciview value in 2064. Using the same point of origination, the projected visibility progress is plotted against the glide path in each figure.

Figures 8.12 and 8.13 illustrate how NDDoH hybrid m odeling projects better visibility improvement to 2018 than WRAP CMAQ modeling for bot h Class I areas. The figures also illustrate how far WRAP and NDDoH projections are f rom meeting the 2018 URP targets for 20% worst day visibility.



### 8.6.2.2 Apportionment by Species

The contribution of individual visibility-affecting species to total observed and projected light extinction for 20% worst/best days is discussed her e. According to the IMPROVE algorithm, light affecting species include sulfate (SO 4 ), nitrate (NO 3 ), organic carbon (OMC), elemental carbon (EC), fine soil (Soil), coarse material (CM) , and sea salt (SS). An additional component of light extinction which is included in the IMPROV E algorithm is Rayleigh scattering (Ray), which was also addressed in the projection of futur e visibility.

IMPROVE speciated monitoring data for 20% worst day s at TRNP and LWA are summarized in the bar charts of Figures 8.14 and 8.15, respective ly. The figures provide the percentage contribution of each visibility-affecting species, as well as Rayleigh scattering, to each 20% worst visibility day in baseline year 2004. The wo rst days are identified by month and day of the

month at the bottom of the charts.

As seen in Figures 8.14 and 8.15, most of the 20% w orst day light extinction at North Dakota Class I areas is dominated by sulfate and nitrate c ontributions. Rayleigh scattering is also a significant component, but otherwise the contributi on of other visibility-affecting species (OMC,140Figure 8.14IMPROVE 20% Worst Days – TRNP 20040%10%20%30%40%50%60%70%80%90%100%19 31 3 6 15 24 4 18 21 11 17 23 1 16 19 18 18 21 27 30 14 5 261 1 2 2 2 2 3 4 5 7 7 7 8 8 8 9 10 10 10 10 11 12 12

Contribution to Extinction% Ray% SS% CM% Soil% EC% OMC% NO3% SO4DayMonth141Figure 8.15IMPROVE 20% Worst Days – LWA 20040%10%20%30%40%50%60%70%80%90%100%1 13 16 19 3 24 27 4 13 22 14 17 23 16 9 18 27 30 14 26 8 26 291 1 1 1 2 2 2 3 3 3 7 7 7 8 9 9 10 10 11 11 12 12 12

Contribution to Extinction% Ray% SS% CM% Soil% EC% OMC% NO3% SO4DayMonth142 

### Table 8.12 Summary of WRAP CMAQ Visibility Projections

for Worst 20% Days at TRNP

Monitored

2000-04

Baseline

Conditions 2064

Natural

Conditions 2018

Uniform

Rate of
Progress
Target 2018

Projected
Visibility

Conditions Baseline to

2018
Change In

Statewide

Emissions Baseline to

2018
Change In
Upwind
Weighted

Emissions 2 Baseline to

2018
Change In
Anthropo
genic
Upwind
Weighted

Emissions 2

(Mm-1) (Mm-1) (Mm-1) 1 (Mm-1) (tons / %) (%) (%)

-97,376

-57%

-37,211

-16%

-1,692

-19%

-2,451

-51%

1,212

2%

12,744

4%

Sea Salt 3 0.07 0.24 0.11

Total Light

Extinction 61.62 22.14 48.41 58.26

Deciview 17.8 7.8 15.47 17.24

WRAP TSS
1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) &

2018 PRP (prp18a) emissions scenarios.

3) Visibility projections not available due to mo del performance issues.

Class I Area Visibility Summary: Theodore Roosevelt NP, ND

Visibility Conditions: Worst 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRP
(prp18a)

Estimated Projected

27% 36% Sulfate 17.53 1 12.23 15.94 -21%

3.92 8.95 10.94 -3% -21%

Nitrate 13.74 1.04 9.85 12.5

-8%

Elemental

Carbon 2.75 0.32 2.13 1.98 -28% -44% Organic

Carbon 10.82

Fine Soil 0.9 0.97 0.91

Coarse

Material 3 4.82 3.66 4.54

Not Applicable 1.02 5% 10%

Not
Applicable 4% 13%143 

### Table 8.13 Summary of WRAP CMAQ Visibility Projections for Bes t 20% Days at

TRNP

Monitored

2000-04

Baseline

Conditions 2064

Natural

Conditions 2018

Uniform

Rate of
Progress
Target 2018

Projected
Visibility

Conditions Baseline to

2018
Change In

Statewide

Emissions Baseline to

2018
Change In
Upwind
Weighted

Emissions 2 Baseline to

2018
Change In
Anthropo
genic
Upwind
Weighted

Emissions 2

(Mm-1) (Mm-1) (Mm-1) 1 (Mm-1) (tons / %) (%) (%)

-97,376

-57%

-37,211

-16%

-1,692

-19%

-2,451

-51%

1,212

3%

12,744

6%

Sea Salt 3 0.03 0.03 Not
Applicable

Total Light

Extinction 21.86 13.57 Not
Applicable 21.67

Deciview 7.76 3.04 Not
Applicable 7.67

WRAP TSS
1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) &

2018 PRP (prp18a) emissions scenarios.

3) Visibility projections not available due to mo del performance issues. Projected

Sulfate 3.82 0.44 Not
Applicable Class I Area Visibility Summary: Theodore Roosevelt NP, ND

Visibility Conditions: Best 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRP
(prp18a)

Estimated

3.88 -9% -9%

Nitrate 1.52 0.31 Not
Applicable 1.41 37% 49%

0.1 Not
Applicable 0.73 -28% -42% -4% -8%

18% Fine Soil 0.4 0.21 Not
Applicable 1.99

0.72 Not
Applicable Organic

Carbon 1.98 0.74 Not
Applicable

Not

Applicable 6% Elemental

Carbon 0.93

Not Applicable 0.43 6% 13%

Coarse

Material 3 2.19144 

### Table 8.14 Summary of WRAP CMAQ Visibility Projections

for Worst 20% Days at LWA

Monitored

2000-04

Baseline

Conditions 2064

Natural

Conditions 2018

Uniform

Rate of
Progress
Target 2018

Projected
Visibility

Conditions Baseline to

2018
Change In

Statewide

Emissions Baseline to

2018
Change In
Upwind
Weighted

Emissions 2 Baseline to

2018
Change In
Anthropo
genic
Upwind
Weighted

Emissions 2

(Mm-1) (Mm-1) (Mm-1) 1 (Mm-1) (tons / %) (%) (%)

-97,376

-57%

-37,211

-16%

-1,692

-19%

-2,451

-51%

1,212

2%

12,744

4%

Sea Salt 3 0.26 0.52 0.32

Total Light

Extinction 74.05 22.52 55.93 70.78

Deciview 19.57 8 16.87 19.12

WRAP TSS
1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) &

2018 PRP (prp18a) emissions scenarios.

3) Visibility projections not available due to mo del performance issues.

Class I Area Visibility Summary: Lostwood NWRW, ND

Visibility Conditions: Worst 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRP
(prp18a)

Estimated Projected

-9%

Nitrate 22.94 1.1 15.56 21.94 -16% -19% Sulfate 21.4

3.79 9.07 19.21 -9% 1.05 14.61

11.68 -7% -11%

Elemental

Carbon 2.84 0.36 2.21 2.07 -32% -40% Organic

Carbon 11.05

Coarse

Material 3 3.93 3.74 3.89 Fine Soil 0.62 0.95 0.7

Not Applicable 0.69 -14% -19%

Not
Applicable -3% -5%145 

### Table 8.15 Summary of WRAP CMAQ Visibility Projections

for Best 20% Days at LWA

Monitored

2000-04

Baseline

Conditions 2064

Natural

Conditions 2018

Uniform

Rate of
Progress
Target 2018

Projected
Visibility

Conditions Baseline to

2018
Change In

Statewide

Emissions Baseline to

2018
Change In
Upwind
Weighted

Emissions 2 Baseline to

2018
Change In
Anthropo
genic
Upwind
Weighted

Emissions 2

(Mm-1) (Mm-1) (Mm-1) 1 (Mm-1) (tons / %) (%) (%)

-97,376

-57%

-37,211

-16%

-1,692

-19%

-2,451

-51%

1,212

3%

12,744

6%

Sea Salt 3 0.03 0.03 Not
Applicable

Total Light

Extinction 22.89 13.4 Not
Applicable 22.58

Deciview 8.19 2.92 Not
Applicable 8.06

WRAP TSS
1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) &

2018 PRP (prp18a) emissions scenarios.

3) Visibility projections not available due to mo del performance issues. Projected

Sulfate 4.39 0.42 Not
Applicable Class I Area Visibility Summary: Lostwood NWRW, ND

Visibility Conditions: Best 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRP
(prp18a)

Estimated

4.47 -1% -1%

Nitrate 1.86 0.34 Not
Applicable 1.65 -16% -19%

0.1 Not
Applicable 0.52 -31% -38% -8% -12%

-10% Fine Soil 0.34 0.22 Not
Applicable 2.27

0.63 Not
Applicable Organic

Carbon 2.26 0.66 Not
Applicable

Not

Applicable -6% Elemental

Carbon 0.71

Not Applicable 0.33 -20% -25%

Coarse

Material 3 2.31146

EC, Soil, CC, and SS) is generally very small. The exception is worst days in late July and August, where organic carbon replaces sulfate and n itrate as the dominate contributor to extinction. This pattern was similar in other year s of IMPROVE baseline data (2000-2003). A possible explanation is that fugitives associated w ith agricultural burning, prescribed burning within Class I areas, and wild fires may be the lar gest contributors to light extinction during late July and August, while emissions from conventional large point sources are the largest contributors during the remainder of the year.

WRAP CMAQ modeling results for the default EPA meth odology were used to review the contribution of individual visibility-affecting spe cies to projected light extinction for 20% worst/best days (NDDoH hybrid modeling did not incl ude all species). Summaries of WRAP CMAQ modeling results including 2018 projections fo r individual species are provided in Tables 8.12 through 8.15. Tables 8.12 and 8.13 provide sp eciated summaries (averages) of 20% worst and best days, respectively, for TRNP. Tables 8.14 and 8.15 address speciated summaries of 20% worst and best days, respectively, for LWA. Th e tables include light extinction values for baseline conditions, natural conditions, 2018 unifo rm rate of progress target, and 2018 projected visibility conditions for each visibility-affecting species. Values for total light extinction and deciview are provided as well (note these values ar e consistent with results in Table 8.11). Note that 2018 projected values are not provided for CM and SS species, due to model performance issues. For these species, WRAP (and NDDoH) assume d an RRF of 1.0, and set the 2018 projection equal to the monitored baseline value.

In reviewing the 20% worst day summaries for TRNP a nd LWA in Tables 8.12 and 8.14, respectively, sulfate and nitrate are found to be t he largest contributors to light extinction. This

is true for both baseline monitored conditions and for future (2018) projected conditions. Because of its dominance in the late summer months, organic carbon is also a major overall contributor to 20% worst day light extinction for b oth baseline monitored and future projected conditions. As discussed previously, WRAP modeling results for 20% worst days (summarized in Tables 8.12 and 8.14) indicate the total light e xtinction URP target will not be achieved at either TRNP or LWA. Further, results for individua l species indicate the URP species-specific target will be met only for elemental carbon and se a salt.

The 20% best day summaries for TRNP and LWA are rep orted in Tables 8.13 and 8.15, respectively. With exception of sea salt, all spec ies appear to be significant contributors to light extinction on 20% best days. Sulfate is the larges t contributor at both TRNP and LWA. As shown in the tables, the 2018 projected light extin ction is lower than the baseline light extinction for both Class I areas. Thus, Regional Haze Rule r equirements for 20% best days will be satisfied at TRNP and LWA for the first planning pe riod.

Note that the WRAP projected emissions values for n itrate (NO X ) in Tables 8.12 through 8.15 are not consistent with the levels used by NDDoH in hybrid modeling. The NDDoH adjusted the

WRAP NO X emissions associated with oil and gas activity, as described in Section 8.5.3.1.147



### 8.6.2.3 Apportionment by Source Group

As established in Section 8.6.2.2, sulfate and nitr ate are the primary contributors to 20% worst day visibility in North Dakota Class I areas. In i ts hybrid modeling analysis, the NDDoH tracked the contribution of source groups to the total pred icted sulfate and nitrate concentration for 20% worst days, in order to enhance the interpretation of modeling results. Contributions are available for the following source groups:

• North Dakota electrical generating units (EGU),

• all other point sources within the CALPUFF domain,

• all sources modeled as area sources within the CALP UFF domain,

• North Dakota oil and gas related sources (O&G), and

• boundary conditions representing the impact of all sources located outside of the CALPUFF

domain.

Focus is on the ND EGU and boundary condition group s because of their relatively small and large contributions, respectively. O&G contributio ns are available for sulfate, only.

Contributions of the above source groups to 20% wor st day average predictions, based on NDDoH hybrid modeling, are illustrated in Figures 8 .16 through 8.19. Predictions for the base period (2000-2004) are compared with predictions fo r the future period (2018) in the figures. Contributions for sulfate at TRNP are compared in F igure 8.16. Figure 8.17 provides contributions for sulfate at LWA. Source group con tributions for nitrate at TRNP are illustrated in Figure 8.18. Finally, Figure 8.19 addresses con tributions for nitrate at LWA. Source group contributions in the figures reflect the percent of the total average predicted concentration for 20% worst days.

As consistently shown in Figures 8.16 through 8.19, the contribution of North Dakota EGUs to total sulfate and total nitrate is relatively small , while the contribution of boundary conditions is relatively large. This is true for both baseline a nd future projections. For sulfate, boundary

conditions contributed no less than two-thirds of t he total at North Dakota Class I areas. For nitrate, the boundary condition contribution was no less than 59 percent. The contribution of North Dakota EGUs to sulfate was no more than 21 pe rcent, and to nitrate was no more than 6 percent, at North Dakota Class I areas.

As shown in Figures 8.16 and 8.17, the reduced impa ct from North Dakota EGUs due to BART controls is apparent. The projected future contrib ution of North Dakota EGUs to sulfate is less

than one-half the baseline contribution for both TR NP and LWA. The difference for other source groups is less pronounced, although an excep tion would be area sources at LWA, where the baseline contribution of 4.0 percent is reduced to 2.4 percent in 2018. In comparing future with baseline contributions in Figures 8.16 and 8.1 7, it appears the contribution of boundary148Figure 8.16Hybrid Modeling ResultsSource Group Contributions to 20% Worst Day SO4at TRNP (Base & Future)ND EGU21.2%Other Point5.8%Area5.5%ND O&G0.9%Boundary66.6%2000-2004ND EGU9.1%Other Point6.3%Area4.7%ND O&G1.0%Boundary78.9%2018149Figure 8.17Hybrid Modeling ResultsSource Group Contributions to 20% Worst Day SO4at LWA (Base & Future)ND EGU12.4%Other Point9.1%Area4.0%ND O&G0.9%Boundary73.6%2000-2004ND EGU5.3%Other Point9.6%Area2.4%ND O&G1.0%Boundary81.7%2018150Figure 8.18Hybrid Modeling ResultsSource Group Contributions to 20% Worst Day NO3at TRNP (Base & Future)ND EGU6.3%Other Point6.3%Area28.4%Boundary59.0%2000-2004ND EGU5.2%Other Point6.8%Area29.0%Boundary59.0%2018151Figure 8.19Hybrid Modeling ResultsSource Group Contributions to 20% Worst Day NO3at LWA (Base & Future)ND EGU4.4%Other Point9.1%Area26.4%Boundary60.1%2000-2004ND EGU4.8%Other Point9.9%Area26.5%Boundary58.8%2018152

conditions is increasing as the contribution of Nor th Dakota EGUs decreases in the future (other source groups remain relatively stable).

In Figures 8.18 and 8.19, the difference between fu ture and baseline contributions for nitrate is less apparent than for sulfate. Percentage contrib utions for nitrate remained relatively stable

from baseline to future for both Class I areas. Re duction in NO X emissions due to BART controls was less than BART reductions for SO2, but the NO X reduction was still significant. This lack of response to future BART reductions in NO X may be linked to the CALPUFF chemistry, and the tendency observed in the perform ance evaluation (Section 8.6.1) for NO 3 production to overreact to newly freed ammonia from the lower production of SO 4

.

NDDoH hybrid modeling results were further refined in order to extract the contribution of all North Dakota sources to total predicted sulfate and nitrate concentrations for 20% worst days. This additional source group includes all North Dak ota EGUs, all North Dakota point sources other than EGUs, and all North Dakota emissions mod eled as area sources. Because the NDDoH CALPUFF domain excludes the far eastern part of Nor th Dakota, some adjustments in inventory and procedure were necessary to estimate the contri bution of this source group.

Contributions of the North Dakota only source group to total sulfate and nitrate are summarized in Table 8.16. Percentage contributions are provid ed for baseline and future predicted

concentrations at both North Dakota Class I areas. As shown in the table, contributions from North Dakota sources are relatively small and compr ise no more than 29 percent of the total prediction for 20% worst days. Significant reducti on in future sulfate concentrations due to BART controls on North Dakota EGUs is again apparen t.



### Table 8.16 Hybrid Modeling Results Total North Dakota Contribution to 20% Worst Days P redictions

Class I Area Baseline Percent 2018 Percent

SO 4 TRNP 27.3 15.0

LWA 17.6 9.7

NO 3 TRNP 29.0 28.6

LWA 26.4 28.7153

The relatively small contributions of North Dakota EGUs (and North Dakota sources in general) and the relatively large contributions of boundary conditions to 20% worst day visibility in North Dakota Class I areas, as observed in Figures 8.16 t hrough 8.19, and Table 8.16, translates to restricted options for meeting visibility progress goals. These results indicate that most of the visibility impact on the 20% worst days in North Da kota Class I areas is due to impact from sources located outside of the State, and beyond th e jurisdiction of the NDDoH. From additional hybrid modeling, the NDDoH found that even with all future North Dakota SO 2 and NO X emissions reduced to zero , North Dakota Class I areas would not achieve the 2018 uniform rate of progress target (see Section 8.6.3).

Weight of evidence perspectives which address the c ontributions of sources located outside of North Dakota to worst day visibility at TRNP and LW A are discussed in Section 8.6.3.



### 8.6.2.4 Apportionment by Source Region

Visibility modeling conducted by WRAP RMC for North Dakota Class I areas included sourceregion attribution for all western states, central US, eastern US, Mexico, and Canada. In addition, WRAP also tracked the contribution of sou rces located outside of the CMAQ domain which includes the contiguous United States, southe rn Canada, and northern Mexico.

Results of the WRAP attribution analysis are summar ized in the bar charts of Figures 8.20 through 8.23. These charts provide source-region c ontributions to baseline (PLAN02c) predicted

concentrations of sulfate and nitrate for the 20% w orst days. Figures 8.20 and 8.21 provide source region contributions for sulfate and nitrate , respectively, at TRNP. Figures 8.22 and 8.23 provide the corresponding contributions at LWA. Al ong with the bars labeled with familiar abbreviations for western states, the figures also include contributions with the following labels:

CAN – Canada, CEN – Central US (CENWRAP), EUS – Eastern US, MEX – Mexico, PO – Pacific Offshore, and OD – Outside WRAP US-Canada-Mexico Modeling Domain

.

The bar charts used in Figures 8.20 through 8.23 we re obtained from the WRAP TSS web site. Note that the values in the charts actually reflect WRAP case PLAN02c, which is a predecessor to the updated PLAN02d. The differences between PL AN02c and PLAN02d, however, are not significant enough to affect conclusions regarding these charts.

In reviewing the bar charts of Figures 8.20 and 8.2 2, it is seen that emissions from North Dakota, Canada, and from outside the WRAP US-Canada-Mexico modeling domain (Figure 8.1)

dominate total sulfate concentrations at North Dako ta Class I areas on the 20% worst visibility days. The contribution of sources located outside the WRAP domain is larger than the

### Source Region Contributions to 20% Worst Day SO

Source Region Contributions to 20% Worst Day NO Source Region Contributions to 20% Worst Day SO Figure WRAP Modeling Results

Figure WRAP Modeling Results Source Region Contributions to 20% Worst Day NO

154 

### Figure 8.20 WRAP Modeling Results Source Region Contributions to 20% Worst Day SO

Figure 8.21 WRAP Modeling Results Source Region Contributions to 20% Worst Day NO WRAP Modeling Results Source Region Contributions to 20% Worst Day SO

WRAP Modeling Results Source Region Contributions to 20% Worst Day NO 4 

### at TRNP (baseline)

3 

### at TRNP (baseline)

### Source Region Contributions to 20% Worst Day SO

Source Region Contributions to 20% Worst Day NO Source Region Contributions to 20% Worst Day SO Figure WRAP Modeling

Figure WRAP Modeling Results Source Region Contributions to 20% Worst Day NO

155 

### Figure 8.22 WRAP Modeling Results Source Region Contributions to 20% Worst Day SO

Figure 8.23 WRAP Modeling Results Source Region Contributions to 20% Worst Day NO Results Source Region Contributions to 20% Worst Day SO

WRAP Modeling Results Source Region Contributions to 20% Worst Day NO 4 

### at LWA (baseline)

3 

### at LWA (baseline)156

contribution from North Dakota sources at both Clas s I areas, and the contribution of Canadian emissions is significantly larger than the contribu tion from North Dakota sources at both Class I

areas.

From Figures 8.21 and 8.23, one observes a similar pattern of dominant source-region contributors for 20% worst day nitrate concentratio ns, except that Montana becomes a dominate contributor in addition to North Dakota, Canada, an d sources located outside of the WRAP

domain. The overall dominance of Canadian emission s is even greater for nitrate than for sulfate, and at LWA the contribution to 20% worst d ay nitrate concentrations from Canadian

sources is more than three times the contribution f rom North Dakota sources.

These source-region apportionment results illustrat e that most of the contributions to 20% worst day nitrate and sulfate (species with the greatest effect on visibility impairment) at North Dakota

Class I areas come from sources located outside of the state. Again, these sources are beyond the jurisdiction of the NDDoH, which poses a dilemma wh en seeking solutions for achieving visibility goals. This issue was addressed in the NDDoH weight of evidence interpretations

which are discussed in Section 8.6.3.



### 8.6.2.5 Conclusions

Visibility progress modeling was conducted by WRAP and NDDoH using the default EPA methodology. This modeling was based on preliminar y estimates of the effect of BART controls, and other growth and control factors. Re sults have been discussed in terms of general status with respect to the uniform rate of progress for North Dakota Class I areas, and in terms of apportionment by species, source group, and source region. Based on these modeling results, the following conclusions apply.

1) The uniform rate of progress goal for 2018 for 20% worst days will not be achieved at either TRNP or LWA. Therefore, weight of evidence argumen ts were addressed (see Section 8.6.3).

2) The Regional Haze Rule requirement for 2018 for 20% best days will be achieved at both

TRNP and LWA.

3) NDDoH hybrid modeling (adjusted WRAP CMAQ) predicte d better progress with respect to the 20% worst day uniform rate of progress goals th an did WRAP modeling, at both TRNP

and LWA.

4) Apportionment modeling results indicate the contrib ution of sources located outside of North Dakota is much greater than the contribution of in- state sources to 20% worst day visibility at TRNP and LWA (both baseline and 2018).

5) Though the addition of proposed BART controls subst antially decreases the visibility impact of North Dakota EGUs, these EGUs comprise only a sm all component of total 20% worst day impact at TRNP and LWA. However, on certain wo rst days when meteorology favors157

transport of North Dakota EGU emissions to TRNP or LWA, proposed BART reductions alone will significantly improve visibility.

6) Of the visibility affecting aerosols, sulfate and n itrate are primary contributors to 20% worst day visibility at North Dakota Class I areas.

7) The primary source-region contributors to 20% worst day visibility at TRNP and LWA are Canada, sources located outside of the WRAP modelin g domain, North Dakota, and Montana (in that order).

8) When implemented as an adjustment to WRAP CMAQ mode ling results, the NDDoH hybrid modeling approach is not critically tied to the par ameterized CALPUFF chemistry.



### 8.6.3 Weight of Evidence Options

WRAP and NDDoH visibility modeling based on the def ault EPA methodology and glide path has been reviewed, with results as discussed in Sec tion 8.6.2. Because projected 2018 visibility did not meet uniform rate of progress goals for 20% worst days in North Dakota Class I areas, the NDDoH pursued alternative or supplemental model ing approaches, which are discussed here. The Regional Haze Rule specifies that the State Imp lementation Plan may be based, in part, on evidence apart from modeling using the default EPA methodology. For example, the analysis could logically be modified to discount the impact of visibility-affecting emission sources over which the NDDoH has no jurisdiction.

These supplemental analyses are defined in the Rule as “weight of evidence” options. The following supplemental modeling analyses were condu cted by NDDoH in the assessment of visibility progress goals.

1) Discounted the impact of international (in this cas e, Canadian) source visibility-affecting

emissions on North Dakota Class I areas.

2) Discounted the impact of visibility-affecting emiss ions from all sources located outside of North Dakota, on North Dakota Class I areas.

3) Used the complete emissions inventory for the defau lt EPA method, but zeroed out future

SO 2 and NO X emissions from all sources located in North Dakota (i.e., assumed 100 percent

future control of all SO 2 and NO X emissions in North Dakota), to determine progress with respect to the default glide path for North Dakota Class I Areas.

4) Based 20% worst visibility days for determining RRF s on baseline model results (CALPUFF) rather than IMPROVE monitoring data. Thi s may be justified because neither CMAQ nor CALPUFF perform well on a “paired-in-time” basis. The resultant RRFs were still applied to 20% worst days based on IMPROVE mo nitoring to project future visibility.158

Procedures and results for these supplemental, weig ht of evidence analyses are discussed in Sections 8.6.3.1 through 8.6.3.4.



### 8.6.3.1 Discounting the Impact of Canadian Sour ce Emissions

The procedure used by the NDDoH to discount the imp act of Canadian source emissions in the projection of future visibility at North Dakota Cla ss I areas is consistent with the methodology described in Section 8.5.6.2. To discount the impa ct of Canadian source emissions on visibility projections, Canadian sources were removed from the baseline and future emissions inventories used with the hybrid modeling system to develop RRF s, and the URP glide path was adjusted by subtracting the impact of Canadian emissions from t he baseline starting value. This weight of evidence analysis was applied for 20% worst days, o nly. The adjusted glide path is compared with the default glide path in Figure 8.24 for TRNP and LWA.

Because the NDDoH hybrid modeling addresses S and N species only, the discounting of Canadian source impact was limited to sulfate and n itrate, only. The RRFs and projected future contribution to light extinction of other visibilit y affecting species remained unchanged from the default EPA methodology (i.e., included Canadian em issions). As sulfate and nitrate are the primary contributors to light extinction at North D akota Class I areas on the 20% worst days (see Section 8.6.2.2), this limitation should not signif icantly impact conclusions based on this weight of evidence analysis.

Note that once the glide path has been adjusted, th e URP 2018 target value changes along with the baseline starting value (the adjusted glide pat h terminates at the same natural background value in 2064). Therefore, it is no longer meaning ful to compare the 2018 projected progress with the absolute deciview target from the default EPA methodology (Table 8.11). Instead, for this weight of evidence scenario and others, 2018 p rogress is expressed as a percentage of the target rather than as a specific deciview value.

The NDDoH procedure used to discount the impact of Canadian source emissions is outlined as

follows.

1) Canadian sources located within the NDDoH CALPUFF d omain were eliminated from the HybridPt baseline and future emissions inventories to be us ed in Equation 8-3.

2) CALPUFF hourly boundary conditions (baseline and fu ture HybridPt ) were adjusted to eliminate the contribution of Canadian (anthropogen ic) source emissions (leaving only the contribution of natural background) for 3-km bounda ry segments located in Canada (see Figure 8.5). The fixed adjustment factor utilized represents the ratio of species-specific natural background light extinction to species-spec ific baseline monitored light extinction for the 20% worst day average, at each Class I area. T he adjustment was applied to all boundary species (SO 2 , SO 4 , NO X , HNO 3 , and NO 3 ). The SO 4 ratio was used for scaling SO 4 and SO 2 species. The NO 3 ratio was used for scaling NO 3 , HNO 3 , and NO X species.159

3) Hybrid modeling was applied to prepare a revised gl ide path and 2018 target using Equation

8-4 with the revised baseline emissions inventories (non-Canadian sources only) from Steps 1 and 2, for each Class I area. The 3-step ammonia limiting method was applied to refine

NO 3 concentrations for non-Canadian sources.

4) Hybrid modeling was applied to project future visib ility using Equation 8-3 with the revised baseline and future emissions inventories (non-Cana dian sources only) from Steps 1 and 2, for each Class I area. The 3-step ammonia limiting method was applied to refine NO 3 concentrations for non-Canadian sources.

5) The projected future deciview value was compared wi th the revised glide path 2018 target deciview value to calculate the percent of the 2018 target achieved, at each Class I area.

Results of the weight of evidence analysis for disc ounting the impact of Canadian source

emissions are summarized in Table 8.17 and illustra ted in Figure 8.24. Uniform rate of progress illustrations in Figure 8.24 are provided for both TRNP and LWA Class I areas. For comparison, the table and figure also include previous WRAP and NDDoH results for the complete emissions inventory and default EPA methodology from Table 8. 11. WRAP results for the default EPA methodology are labeled Scenario 1 and NDDoH result s for the default EPA methodology are labeled Scenario 2. They are compared with the wei ght of evidence entry which is identified as Scenario 3. For each scenario, the table provides percentage progress with respect to the 2018

target.160 

### Table 8.17 NDDoH Visibility Modeling Results 20% Worst Days Weight of Evidence – Discounting Canadian Emissions

Projected Scenario Description Class I Area Percent of 2018 Target

WRAP CMAQ TRNP 24.0 1 Default EPA Methodology

LWA 16.7

NDDoH Hybrid TRNP 38.1 2 Default EPA Methodology

LWA 26.7

NDDoH Hybrid TRNP 50.0

3 Canada Sources Discounted

LWA 40.2

As shown in Table 8.17 and Figure 8.24, progress wi th respect to the 2018 target is significantly improved when Canadian sources are discounted. The projected percent of the 2018 target with

Canadian sources discounted is more than double the percentage obtained by WRAP for the default EPA methodology, and about 50 percent great er than the percentage obtained by NDDoH for the default EPA methodology, at both Class I ar eas. Though progress is significantly161 

### Figure 8.24 Uniform Rate of Progress EPA Default Methodology and Canadian Sources Discou nted

2004 2024 2044 2064 Y e a r 6 8 10 12 14 16 18 20Deciview Predicted Progress to 2018

WRAP - Scenario 1

NDDoH - Scenarios 2,3 LWA

A l S o u r c e s G l i d e P at h C a n a d i a n S o u r c e s D i s c o u n t e d G l i d e P a t h 1

2

3

2018 2004 2024 2044 2064 Y e a r 6 8 10 12 14 16 18Deciview Predicted Progress to 2018

WRAP - Scenario 1

NDDoH - Scenarios 2,3 TRNP

A l S ou r c e s G l i d e P a t h C a n a d i a n S o u r c e s D i s c o u n t e d G l i d e P a t h 1

2

3

2018162

improved under this scenario, the potential for gre ater improvement was limited because the

contribution of US sources located outside of the h ybrid model domain is very large (with little emissions reduction in the future), and the scenari o could only address the discounted impact of

SO 4 and NO 3

.



### 8.6.3.2 Discounting the Impact of All Sources L ocated Outside of North Dakota

Because discounting the impact of Canadian emission s did not provide compliance with glide path targets, the NDDoH pursued other weight of evi dence options. The next logical test after discounting Canadian emissions was to discount the visibility-affecting impact of all sources located outside of the jurisdiction of the NDDoH. Therefore, this new analysis discounted all contributions to North Dakota Class I areas, except for the impact of North Dakota sources and natural background. To discount the impact of all sources located outside of North Dakota on visibility projections, these sources were removed from the baseline and future emissions inventories used with the hybrid modeling system to develop RRFs, and the URP glide path was adjusted by subtracting the impact of these sources from the baseline starting value. This weight of evidence analysis was applied for 20% worst days , only. The adjusted glide path is compared with the default glide path in Figure 8.25 for TRNP and LWA.

Since the CALPUFF domain used by the NDDoH for hybr id visibility modeling excludes the extreme eastern part of North Dakota, area emission s for the easternmost column of the area source grid (see Figure 8.8) were adjusted upward t o account for the impact of eastern North Dakota sources. Specifically, WRAP CMAQ (SMOKE) em issions for all grid cells located between the eastern edge of the CALPUFF domain and the eastern North Dakota border were

added to the easternmost column of the CALPUFF area source grid. This addition was performed on a row by row basis. Because eastern N orth Dakota visibility affecting sources are relatively small and distant from TRNP and LWA Clas s I areas, this adjustment should have minimal impact on modeling results.

Because the NDDoH hybrid modeling addresses S and N species only, the discounting of out-ofstate source impact was limited to sulfate and nitr ate, only. The RRFs and projected future contribution to light extinction of other visibilit y affecting species remained unchanged from the default EPA methodology (i.e., included complete em issions inventory). As sulfate and nitrate are the primary contributors to light extinction at North Dakota Class I areas on most of the 20% worst days (see Section 8.6.2.2), this limitation s hould not significantly impact conclusions based on this weight of evidence analysis.

The procedure used by NDDoH to discount the impact of all sources located outside of North

Dakota is similar to the 5-step procedure used to discoun t Canadian emissions, as outlined in Section 8.6.3.1., except that variables representin g North Dakota sources replaced variables representing US sources in Equations 8.3 and 8.4. The procedure for discounting the impact of

all out-of-state sources is outlined below.

1) All out-of-state sources located within the NDDoH C ALPUFF domain were eliminated from

the HybridPt

baseline and future emissions inventories to be us ed in Equation 8-3.163

2) As discussed above, emissions from all sources loca ted outside of CALPUFF domain, but inside North Dakota, were added to easternmost colu mn of CALPUFF area source grid.

3) CALPUFF hourly boundary conditions (baseline and fu ture HybridPt ) were scaled to

eliminate the contribution of all out-of-state sour ce emissions (leaving only the contribution of natural background) for all boundary segments. Scaling was based on the inverse distance squared weighted average of natural-to-baseline (20 02) ratio from seven nearby IMPROVE monitoring locations. The ratio was obtained for t he 20% worst day average SO 4 and NO 3 natural and baseline extinction for Theodore Roosev elt NP, Lostwood NWA, Medicine Lake NWA, UL Bend, Badlands NP, Wind Cave, and Voyageurs NP IMPROVE sites. The average SO 4 ratio was used for scaling SO 4 and SO 2 species. The average NO 3 ratio was used for scaling NO 3 , HNO 3 , and NO X species.

4) Hybrid modeling was applied to prepare a revised gl ide path and 2018 target using Equation

8-4 with the revised baseline emissions inventories from Steps 1 and 2, for each Class I area (equation variables for North Dakota sources replac ed variables for US sources). The 3-step ammonia limiting method was applied to determine NO 3 concentrations for North Dakota

sources.

5) Hybrid modeling was applied to project future visib ility using Equation 8-3 with the revised baseline and future emissions inventories from Step s 1 and 2, for each Class I area (equation variables for North Dakota sources replaced variabl es for US sources). The 3-step ammonia limiting method was applied to determine NO 3 concentrations for US sources.

6) The projected future deciview value was compared wi th the revised glide path 2018 target deciview value to calculate the percent of the 2018 target achieved, at each Class I area.

Results of the weight of evidence analysis for disc ounting the impact of all sources located outside of North Dakota are summarized in Table 8.18 and illustrated in Fi gure 8.25. Uniform rate of progress illustrations in Figure 8.25 are p rovided for both TRNP and LWA Class I areas. For comparison, the table and figure also include p revious WRAP and NDDoH results for the complete emissions inventory with default EPA metho dology from Table 8.11. WRAP results for the default EPA methodology are labeled Scenari o 1 and NDDoH results for the default EPA methodology are labeled Scenario 2. They are compa red with the new weight of evidence entry

which is identified as Scenario 4. For each scenar io, the table provides percentage progress with respect to the 2018 target.

As shown in Table 8.18 and Figure 8.25, progress wi th respect to the 2018 target is significantly improved after discounting the impact of all sources located outside of North Dakota , but projections do not meet the revised glide path targ ets. Also, the improvement is notably better at TRNP than at LWA. A likely explanation is that the location of BART sources in North Dakota, combined with prevailing meteorology, favors visibi lity improvement at TRNP compared with improvement at LWA (i.e., when there are no out of state influences).164 

### Table 8.18 NDDoH Visibility Modeling Results 20% Worst Days Weight of Evidence – Discounting All Out-of-State S ources

Projected Scenario Description Class I Area Percent of 2018 Target

WRAP CMAQ TRNP 24.0 1 Default EPA Methodology

LWA 16.7

NDDoH Hybrid TRNP 38.1 2 Default EPA Methodology

LWA 26.7

NDDoH Hybrid TRNP 83.9

4 All Sources Other Than ND Discounted

LWA 59.6



### 8.6.3.3 Use Default EPA Methodology with Zero N orth Dakota Future Emissions

The NDDoH next examined a “what if” scenario to see what would happen if all North Dakota sources were controlled to the hypothetical maximum degree and simply emitted no SO 2 , SO 4 , NO X , or NO 3 in the future case. The concept here was to deter mine if the 2018 URP targets for the default EPA methodology for 20% worst days coul d be achieved even under maximum (albeit unrealistic) control conditions for North D akota sources. Hybrid modeling for the baseline case ( HybridPt

in Equation 8-3) included the complete emissions i nventory as used for the NDDoH EPA methodology analysis. Future case mo deling ( HybridPt in Equation 8-3) included the complete emissions inventory as applie d by NDDoH for EPA methodology, except

that all emissions for sources located in North Dak ota were reset to zero. For this scenario, the glide path remains consistent with the default EPA methodology scenario.

Procedure for this new scenario followed the defaul t EPA methodology, as discussed in Section 8.5. The only change was in the future case emissi ons inventory, where the emission rates for all North Dakota point and area sources were reset to z ero. Note that because extreme eastern North Dakota is not included in the NDDoH CALPUFF domain, it was not possible to model the effect of zero future emissions from that part of the stat e. However, because visibility-affecting

sources in extreme eastern North Dakota are relativ ely small and distant from the Class I areas165 

### Figure 8.25 Uniform Rate of Progress EPA Default Methodology and Non-ND Sources Discount ed

2004 2024 2044 2064 Y e a r 6 8 10 12 14 16 18Deciview Predicted Progress to 2018

WRAP - Scenario 1

NDDoH - Scenarios 2,4 TRNP

A l S ou r c e s G l i d e P a t h

ND S o u r c e s G l i d e P a t h 1

2

4

2018

2004 2024 2044 2064 Y e a r 6 8 10 12 14 16 18 20Deciview Predicted Progress to 2018

WRAP - Scenario 1

NDDoH - Scenarios 2,4 LWA

A l S o u r c e s G l i d e P at h

N D S o u r c e s G l i d e P a t h 1

2

4

2018166

which are both located in the western part of the s tate, this limitation should not detract from conclusions established regarding the analysis.

Results of the weight of evidence analysis involvin g zero future emissions for North Dakota visibility affecting sources are summarized in Tabl e 8.19. For comparison, the table also includes previous WRAP and NDDoH results for the co mplete emissions inventory with default EPA methodology from Table 8.11. WRAP results for the default EPA methodology are labeled

Scenario 1 and NDDoH results for the default EPA me thodology are labeled Scenario 2. They are compared with the new weight of evidence entry which is identified as Scenario 5. For each scenario, the table provides percentage progress wi th respect to the 2018 target.

As illustrated in Table 8.19, even with all future North Dakota SO 2 , SO 4 , NO X , and NO 3 emissions set to zero, the URP 20% worst day target s for 2018 are not achieved at North Dakota

Class I areas. This result is consistent with earl ier conclusions in this report that most of the visibility affecting impact on TRNP and LWA is comi ng from sources located outside of North Dakota. The implication of this weight of evidence test is that compliance with 20% worst day URP targets at North Dakota Class I areas cannot be achieved without significant additional emissions reductions from visibility affecting sour ces located outside of North Dakota.



### Table 8.19 NDDoH Visibility Modeling Results 20% Worst Days Weight of Evidence – Zero Future North Dakota Emiss ions

Projected Scenario Description Class I Area Percent of 2018 Target

WRAP CMAQ TRNP 24.0 1 Default EPA Methodology

LWA 16.7

NDDoH Hybrid TRNP 38.1 2 Default EPA Methodology

LWA 26.7

NDDoH Hybrid TRNP 83.8

5 Base Emissions Inv = Default

Future Emissions Inv = All ND LWA 72.6

S and N Emissions set to zero167

As indicated previously, the NDDoH CALPUFF visibili ty modeling was limited to the

contribution of SO 2 , SO 4 , NO X , and NO 3 species, only. Even if the effect of zeroing out all other visibility affecting species could have been accoun ted for, it is unlikely that 2018 URP targets for

North Dakota Class I areas could have been achieved under this weight of evidence scenario.



### 8.6.3.4 Base 20% Worst Days on Modeling Results Rather than IMPROVE Monitoring Data

Though both models perform well when predicting max imum concentrations over a period of time, CMAQ and CALPUFF are less reliable when perfo rmance tests are based on predictions paired with concurrent observations. But the relia nce of the Regional Haze Rule on the 20% worst/best monitored days to track visibility progr ess implies that the modeling system must demonstrate some skill on a temporal basis. To add ress possible temporal performance limitations in the NDDoH hybrid modeling system, vi sibility projection results based on the 20% worst monitored days were compared with results bas ed on the 20% worst modeled days for the baseline case. The following procedure was used to develop results based on worst modeled days.

1) The hybrid modeling system was executed for the bas eline case, using the emissions inventory for the default EPA methodology, and the entire year of 2002 meteorological data.

2) Daily modeling results for the baseline case were r anked in order to determine the 20% worst days (73 days) for visibility at both Class I areas (TRNP and LWA).

3) The hybrid modeling system was executed for the fut ure (2018) case, using the emissions inventory for the default EPA methodology, and the 20% worst days determined for the baseline case in Step 2.

4) Relative response factors (RRFs) were developed fro m the modeling results for baseline and future cases in Steps 1 and 3, respectively.

5) RRFs were applied to IMPROVE baseline monitoring da ta for original 20% worst days to project future visibility.

This procedure provided deciview improvement predic tions which were very similar to the original improvement predictions obtained through m odeling the 20% worst IMPROVE days. Typical differences were less than five percent of the original predicted values at both Class I areas. Therefore, the NDDoH did not pursue this ap proach for any of the visibility modeling documented in this report (i.e., all modeling was b ased on the 20% worst/best IMPROVE days).168



### 8.6.3.5 Weight of Evidence Summary and Conclusi ons

Results of the weight of evidence modeling analyses are summarized in Table 8.20, and in the illustrations of Figures 8.26 and 8.27. For compar ison, the table and figures include results from all weight of evidence analyses, as well as previou s WRAP and NDDoH results for the complete emissions inventory and default EPA methodology fro m Table 8.11. Scenarios are labeled as previously noted. For each scenario, the table pro vides percentage progress with respect to the 2018 target for 20% worst days at both North Dakota Class I areas. Figure 8.26 illustrates progress with respect to the URP glide path at TRNP for all scenarios, and Figure 8.27 illustrates progress with respect to the URP glide path at LWA for all scenarios.

Conclusions based on weight of evidence modeling an alyses follow.

1) Compliance with 20% worst day URP 2018 targets at N orth Dakota Class I areas cannot be achieved through additional emissions reductions fr om North Dakota sources, alone. It will require significant additional visibility affecting emissions reductions from other western states, Canada, and from sources located outside of the WRAP CMAQ modeling domain.

2) A visibility progress analysis methodology which di scounts the impact of International (Canadian) visibility affecting source emissions on 20% worst days is plausible, and was developed and implemented by the NDDoH. Using simi lar methodology, the NDDoH was able to also develop and implement a procedure to d iscount the impact of all sources located outside of North Dakota on 20% worst days.

3) After discounting the impact of Canadian sources, s ignificantly greater progress (50 percent greater) was demonstrated, relative to URP 2018 tar gets for North Dakota Class I areas, than modeling with the entire emissions inventory. But 20% worst day targets were still not

achieved.

4) After discounting the impact of all sources located outside of North Dakota , even greater progress was demonstrated, relative to URP 2018 tar gets for North Dakota Class I areas, than modeling with Canadian sources discounted. However , 20% worst day targets were still not

achieved.

5) After zeroing out all future SO 2 and NO X emissions in North Dakota under default EPA methodology (emulating a 100 percent, unrealistic c ontrol of all sources), compliance with 20% worst day targets was still not achieved at Nor th Dakota Class I areas.

6) Basing 20% worst days on baseline model results rat her than IMPROVE monitoring data made no meaningful difference in future visibility projections.169 

### Table 8.20 NDDoH Visibility Modeling Results 20% Worst Days Weight of Evidence Analysis Summary

Projected Scenario Description Class I Area Percent of 2018 Target

WRAP CMAQ TRNP 24.0 1 Default EPA Methodology

LWA 16.7

NDDoH Hybrid TRNP 38.1 2 Default EPA Methodology

LWA 26.7

NDDoH Hybrid TRNP 50.0

3 Canada Sources Discounted

LWA 40.2

NDDoH Hybrid TRNP 83.9

4 All Sources Other Than ND Discounted

LWA 59.6

NDDoH Hybrid TRNP 83.8

5 Base Emissions Inv = Default

Future Emissions Inv = All ND LWA 72.6

SO 2 and NO X Emissions set to zero170Figure 8.26TRNP Uniform Rate of ProgressEPA Default Methodology and NDDoH Weight of Evidence2004 2024 2044 2064Year681012141618

D e c i v i e wPredicted Progress to 2018WRAP - Scenario 1NDDoH - Scenarios 2,3,4Zero Future ND - Scenario 5

A l l S o u r c e s G l i d e P a t h

C a n a d i a n S o u r c e s D i s c o u n t e d G l i d e P a t h

N D S o u r c e s G li d e P a t h125342018171Figure 8.27LWA Uniform Rate of ProgressEPA Default Methodology and NDDoH Weight of Evidence2004 2024 2044 2064Year68101214161820

D e c i v i e wPredicted Progress to 2018WRAP - Scenario 1NDDH - Scenarios 2,3,4Zero Future ND - Scenario 5

A l l S o u r c e s G l i d e P a t h

C a n a d i a n S o u r c e s D i s c o u n t e d G l i d e P a t h

N D S o u r c e s G l i d e P a t h125342018172



## 9. Reasonable Progress Goals

9.1 Introduction

The Regional Haze Rule states that for each mandato ry Class I Federal area located within the State and in each mandatory Class I Federal area lo cated outside the State which may be affected by emissions from within the State, the State must establish reasonable progress goals for each

area. For out-of-state Class I areas that are affe cted by in-state emissions, the State must consult with the affected state regarding the reasonable pr ogress goals for those Class I areas. The reasonable progress goals (expressed in deciviews) must provide for reasonable progress towards achieving natural visibility conditions including i mprovement in visibility for the most impaired days (20% worst days) and ensuring no degradation i n visibility for the least impaired days (20% cleanest days) over the planning period.

The EPA has published guidance 1 for setting reasonable progress goals. The basic steps include:

1. Establish Baseline and Natural Visibility Condit ions

2. Determine the Glidepath, or Uniform Rate of Prog ress

3. Identify and Analyze the Measures Aimed at Achie ving the Uniform Rate of Progress

a. Identify the key pollutants and sources and/or s ource categories that are contributing to visibility impairment at each Class I area. The sources of impairment for the most impaired and least impaired days may differ.

b. Identify the control measures and associated emi ssion reductions that are expected to result from compliance with existing rules and o ther available measurements for the sources and source categories that contribu te significantly to visibility impairment.

c. Determine what additional control measures would be reasonable based on the statutory factors and other relevant factors for th e sources and/or source categories you have identified.

d. Estimate through the use of air quality models t he improvement in visibility that would result from implementation of the control mea sures you have found to be reasonable and compare this to the uniform rate of progress.

4. Establish the Reasonable Progress Goal

1 U.S. EPA 2007; Guidance for Setting Reasonable Pro gress Goals under the Regional Haze Rule: U.S. Environmental Protection A gency, Office of Air Quality Planning and Standards, Research Triangle Park, NC, June 1, 2007

.173



### 9.2 Establish Baseline and Natural Visibility Condi tions

The baseline visibility conditions are established in Section 5.3 while the natural visibility

conditions are addressed in Section 5.4. The follo wing table summarizes the results for North

Dakota’s Class I Federal areas.

Table 9.1 Baseline and Natural Visibility Conditions

Area Baseline (dv) Natural Conditions (dv)

20% Best 20% Worst 20% Best 20% Worst

TRNP 7.8 17.8 3.0 7.8

LWA 8.2 19.6 2.9 8.0



### 9.3 Determine the Glide Path or Uniform Rate of Pro gress

The uniform rate of progress necessary to achieve n atural conditions is addressed in Section 5.4. The results of that analysis are as follows:

Table 9.2 Visibility Improvement Required

Area Total Improvement Required (dv) 20% Worst Days 2018 Target Improvement (dv) 20% Worst Days

TRNP 10.0 2.3

LWA 11.6 2.7



### 9.4 Identify and Analyze the Measures Aimed at Achi eving the Uniform Rate of Progress

A. Identify key pollutants and sources contributing to visibility impairment in each Class I

area.

The key pollutants contributing to visibility degra dation in North Dakota’s Class I areas are sulfur dioxide and nitrogen oxides which form s ulfates and nitrates (see analysis in Section 8.7.2.2). For sulfates, the contributing s ources are primarily point sources in Canada, sources outside WRAP’s modeling domain and point sources in North Dakota.For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources

outside of WRAP

Section 6.3 and Section 19% of the nitrate at TRNP during the 20% worst day s of the baseline 02c) nitrate for the same period.

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total

extinction at TRNP and 14 seen in Figures 9.1 and 9.2, m from the “natural fire” source category or from the “fugitive dust” categor

cannot be controlled

Section decrease 54% by 2018. For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources

outside of WRAP

Section 6.3 and Section 19% of the nitrate at TRNP during the 20% worst day s of the baseline 02c) . At LWA, North Dakota sources contributed 18% of nitrate for the same period.

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total

extinction at TRNP and 14 seen in Figures 9.1 and 9.2, m from the “natural fire” source category or from the “fugitive dust” categor

cannot be controlled

Section s 9.5.2 decrease 54% by 2018. For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources

outside of WRAP ’ s modeling domain area are the primar

Section 6.3 and Section 19% of the nitrate at TRNP during the 20% worst day s of the baseline . At LWA, North Dakota sources contributed 18% of nitrate for the same period.

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total

extinction at TRNP and 14 seen in Figures 9.1 and 9.2, m from the “natural fire” source category or from the “fugitive dust” categor

cannot be controlled and will vary year to year in each state

9.5.2 and 10.6.2 decrease 54% by 2018. For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources

s modeling domain area are the primar

Section 6.3 and Section 8). North Dakota sources contributed 21% of the sulfate and 19% of the nitrate at TRNP during the 20% worst day s of the baseline . At LWA, North Dakota sources contributed 18% of nitrate for the same period.

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total

extinction at TRNP and 14 .9% at LWA seen in Figures 9.1 and 9.2, m uch of the organic carbon from the “natural fire” source category or from the “fugitive dust” categor

and will vary year to year in each state

and 10.6.2 . Off- road mobile sources o

174 For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources

s modeling domain area are the primar

North Dakota sources contributed 21% of the sulfate and 19% of the nitrate at TRNP during the 20% worst day s of the baseline . At LWA, North Dakota sources contributed 18% of

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total

.9% at LWA during the uch of the organic carbon from the “natural fire” source category or from the “fugitive dust” categor

and will vary year to year in each state

road mobile sources o

Figure 9.1 For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources

s modeling domain area are the primar y contributors (see analysis in

North Dakota sources contributed 21% of the sulfate and 19% of the nitrate at TRNP during the 20% worst day s of the baseline . At LWA, North Dakota sources contributed 18% of

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total during the baseline uch of the organic carbon emissions in North Dakota are from the “natural fire” source category or from the “fugitive dust” categor

and will vary year to year in each state . Fugitive

road mobile sources o f organic carbon are expected to

Figure 9.1 For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources y contributors (see analysis in

North Dakota sources contributed 21% of the sulfate and 19% of the nitrate at TRNP during the 20% worst day s of the baseline (WRAP Case Plan . At LWA, North Dakota sources contributed 18% of the sulfate and 13% of the

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total

baseline 20% worst days

emissions in North Dakota are from the “natural fire” source category or from the “fugitive dust” categor . Fugitive dust is addressed in organic carbon are expected to For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources y contributors (see analysis in

North Dakota sources contributed 21% of the sulfate and (WRAP Case Plan

the sulfate and 13% of the

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total 20% worst days

. As can be

emissions in North Dakota are from the “natural fire” source category or from the “fugitive dust” categor y . Natural fire

dust is addressed in organic carbon are expected to For nitrates, point/area/mobile sources in Canada, North Dakota, Montana and sources y contributors (see analysis in

North Dakota sources contributed 21% of the sulfate and (WRAP Case Plan

the sulfate and 13% of the

Organic carbon (primary organic aerosols) is the ne xt largest contributor to extinction in the Class I areas of North Dakota. Organic carbon contributes 17.5% of the total

As can be

emissions in North Dakota are

. Natural fire

dust is addressed in organic carbon are expected toWith regard to

concentration in the Class I areas

Area

TRNP

LWA

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North With regard to

concentration in the Class I areas

Area Source

TRNP Point Anthropogenic Fire

Mobile Natural Fire & Biogenic

Area

LWA Point Anthropogenic Fire

Mobile Natural Fire & Biogenic

Area

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North With regard to the contribution of North Dakota sources to the

concentration in the Class I areas

Source

Point Anthropogenic Fire

Mobile Natural Fire & Biogenic

Point Anthropogenic Fire

Mobile Natural Fire & Biogenic

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North Figure 9.2

the contribution of North Dakota sources to the

concentration in the Class I areas , the sources in North Dakota are:

North Dakota Sources

Sulfate and Nitrates

Contribution

Anthropogenic Fire

Natural Fire & Biogenic

Anthropogenic Fire

Natural Fire & Biogenic

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North

175 Figure 9.2

the contribution of North Dakota sources to the

, the sources in North Dakota are:

Table 9.3

North Dakota Sources

of

Sulfate and Nitrates

2000- 2004

In-State

Sulfate

Contribution (μg/m 3 )

0.3148

0.0002

0.0151

0.0002

0.0071

0.3797

< 0.0001

0.0216

0.0004

0.0089

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North

the contribution of North Dakota sources to the

, the sources in North Dakota are:

Table 9.3

North Dakota Sources

Sulfate and Nitrates

2004

In- State

Nitrate

Contribution (μg/m 3 )

0.1587

0.0003

0.1038

0.0389

0.0233

0.1760

< 0.0001

0.1197

0.0362

0.0334

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North

the contribution of North Dakota sources to the sulfate

, the sources in North Dakota are:

State

Contribution

) Percent of Total

In- State Contribution

Sulfate

98

< 1

4

< 1

2

0.0001 92

< 1

5

< 1

2

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North sulfate s and nitrate

Percent of Total

State Contribution

Sulfate Nitrate

49

< 1

32

12

7

48

< 1

33

10

9

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North and nitrate s

Percent of Total

State Contribution

Nitrate

1

1

North Dakota sources only contribute 21% of the tot al sulfate concentration in TRNP and 19% of the total nitrate concentration during the 2 0% worst days. At LWA, North176

Dakota sources contribute 18% of the total sulfate and 13% of the total nitrate (see Table 2.1). Although mobile sources are a significant con tributor to North Dakota’s emissions that form nitrates, mobile sources in North Dakota only contribute 6% of the total nitrate concentration in TRNP and 4% in LWA during the 20% worst days (WRAP Case Plan 02c). Nitrogen oxides emissions from mobile source s are expected to decline by 51% by 2018 (see Table 6.1 and 6.3). Based on the above r esults, efforts to reduce sulfates and nitrates are primarily directed towards point sourc es of sulfur dioxide and nitrogen oxides

emissions.

B. Identify the Control Measures and Associated Emi ssion Reductions from Existing Rules

See Section 10. The WRAP has estimated that the “o n-the-books” controls will reduce emissions of nitrogen oxides by approximately 28,00 0 tons per year, sulfur dioxide 1,700 tons per year, elemental carbon 2,700 tons per year , and fine particulate matter by 900 tons per year. Coarse particulate matter is expect ed to increase by 18,000 tons primarily due to fugitive dust. These “on the books” control s include:

• Tier 1 light-duty vehicle standards, beginning MY 1 996;

• National Low Emission Vehicle (NLEV) standards, beg inning MY 2001;

• Tier 2 light-duty vehicle standards beginning MY 20 05, with low sulfur gasoline beginning summer 2004;

• Heavy-duty vehicle standards beginning MY 2004;

• Heavy-duty vehicle standards beginning MY 2007, wit h low sulfur diesel beginning summer 2006;

• Emission standards for new nonroad spark-ignition e ngines below 25 hp;

• Phase 2 emission standards for new spark-ignition h and-held engines below 25 hp;

• Phase 2 emission standards for new spark-ignition n onhand-held engines below 25 hp;

• Emission standards for new gasoline spark-ignition marine engines;

• Tier 1 emission standards for new nonroad compressi on-ignition engines above 50 hp;

• Tier 1 and Tier 2 emission standards for new nonroa d compression-ignition engines below 50 hp including recreational marine e ngines;

• Tier 2 and Tier 3 standards for new nonroad compres sion-ignition engines of 50 hp and greater not including recreational marine en gines greater than 50 hp; and

• Tier 4 emissions standards for new nonroad compress ion-ignition engines above 50 hp, and reduced nonroad diesel fuel sulfur level s.

Modeling by the WRAP indicates these “on-the-books” rules will improve visibility by 0.1 deciviews in the 20% worst day at TRNP and 0.2 deciviews at LWA.

C. Determine What Additional Control Measures Would be Reasonable Based on the Statutory Factors and Other Relevant Factors

See Section 9.5 and 9.6.177

D. Estimate Through the Use of Air Quality Models t he Improvement in Visibility that Would Result From the Implementation of the Control Measures Found to be Reasonable

See Section 9.5.

E. Establish the Reasonable Progress Goals

See Section 9.7.



### 9.5 Additional Controls

9.5.1 Point Sources Contributing to Visibility Imp airment in the North

Dakota Class I Areas

In determining reasonable progress goals for any Cl ass I Federal area, 40 CFR 51.308(d)(1)(i)(A) requires a state to consider the costs of compliance, the time necessary for compliance, the energy and non-air quality environm ental impacts of compliance, and the remaining useful life of any potentially affected s ources, and include a demonstration showing

how these factors were taken into consideration in selecting the goal.

In determining the cost of compliance for individua l sources or source categories potentially subject to emission limitations, the following step s are suggested:

A. Identify the emission units to be controlled.

B. Identify the design parameters for emission cont rols, and

C. Develop cost estimates based upon those design p arameters.

The Guidance for Setting Progress Goals under the R egional Haze Program states “it is not necessary for you to reassess the reasonable progre ss factors for sources subject to BART for which you have already completed a BART analysis.”



### Cost of Compliance

Step 1: Identify Emission Units to be Controlled

The Department has identified sulfur dioxide and ni trogen oxides as the primary pollutants that are emitted by stationary point sources that contri bute most of the visibility impairment. Particulate emissions from stationary sources have very little impact on visibility in North Dakota (see Figures 6.5 and 6.6) and represent only 1% of the total PM emissions in 2002 (see Table 6.1). Therefore, PM emissions from point sou rces were not evaluated under this section.178

Under BART, it was determined that no additional co ntrols were required for the largest sources of PM, the electric utility steam generating units. Primary sulfuric acid mist emissions are also a very small contributor to visibility impairment. T he sources that were subject to BART, the largest emitters of sulfuric acid mist, were evalua ted for emissions of this pollutant. Because of the small impact of sulfuric acid mist on visibilit y, sulfuric acid mist was not included in the reasonable progress analysis.

To identify point sources in North Dakota that pote ntially affect visibility in Class I Federal areas, the list of sources subject to Title V permi tting requirements was established as the starting point. This represents more than 99% of the sulfur dioxide emissions from all point sources in North Dakota that have an operating permit (Title 5 or Minor Source Operating Permit) and greater than 98% of the nitrogen oxides emissions b ased on 2007 data. The sources subject to BART were also eliminated from the list as suggeste d by EPA guidance. The Department has

included all controls on BART sources that have a r easonable cost. Any controls rejected under BART would also be rejected under the four factors for determining reasonable progress. Although sources were excluded from this analysis, all sources, including sources subject to BART, will be reviewed during future planning perio ds.

To further evaluate the list of sources, the actual emissions from the source were compared to the

distance the source is located from the nearest Cla ss I Federal area. The Department has determined from previous BART modeling that particu late matter emissions from point sources have a very small contribution to visibility impair ment in the Class I areas. Therefore, only emissions of nitrogen oxides and sulfur dioxide wer e evaluated in this comparison. The Department initially used the average of the 2000-2 004 emission rate for this analysis. The emission rate (Q) in tons per year was divided by t he distance (D), in kilometers, to the nearest Class I area. A value of Q/D greater than 10 was c hosen as a point for further evaluation of those sources. A Q/D of greater than 10 was chosen based on the FLM’s proposed FLAG guidance amendments initial screening criteria for sources that may affect air quality related values. In addition, EPA in the preamble to the BA RT Guideline states, “Our analyses of visibility impacts from model plants provide a usef ul example of the type of analyses that might be used to exempt categories of sources from BART. Based on our model plant analysis, EPA believes that a State could reasonably choose to ex empt sources that emit less than 500 tons per year of NO

x or SO 2 (or combined NO

x and SO 2 ), as long as they are located more than 50 kilometers from any Class I area; and sources that emit less than 1000 tons per year of NO

x or SO 2 (or combined NO

x and SO 2 ) that are located more than 100 kilometers from an y Class I area.” EPA’s criteria is equivalent to a Q/D of 10 . For all sources, except EGUs, the total SO 2 and NO

x emissions from the facility were used and no disti nction was made for individual units. EGU’s were separated by units because they can act as standalone facilities while other process

units cannot.179 Table 9.4 North Dakota Title V Sources Q/D Analysis

Permittee Plant SO 2 + NO

x 2000-2004 Average (tons) Nearest

Class I Area Distance

to Nearest

Class I Area (km) Nearest

Q/D (tons/km)

ADM Corn Processing Walhalla Ethanol Plant 287 Lost wood 324 0.9

ADM Processing Velva Facility 45 Lostwood 125 0.4

Alliance Pipeline Fairmount Comp. Station 58 Voyage urs 327 0.2

Alliance Pipeline Towner Comp. Station 57 Lostwood 120 0.5

Alliance Pipeline Wimbledon Comp. Station 60 Lostwo od 335 0.2

American Crystal Sugar Co. Drayton Sugarbeet Plant 1,109 Voyageurs 294 3.8

American Crystal Sugar Co. Hillsboro Sugarbeet Plan t 1,085 Voyageurs 315 3.4

Basin Electric AVS Unit 1 13,864 TRNP/NU 107 129.6

Basin Electric AVS Unit 2 12,796 TRNP/NU 107 119.6

Bear Paw Energy Alexander Comp. Station 139 TRNP/NU 36 3.9

Bear Paw Energy Fort Buford Comp. Station 42 TRNP/N U 44 1.0

Bear Paw Energy Grasslands Gas Plant 748 TRNP/NU 38 19.7

Bear Paw Energy Lignite Gas Plant 463 Lostwood 15 3 0.9

Bear Paw Energy Tree Top Comp. Station 54 TRNP/SU 1 7 3.2

Cargill Corn Milling Wahpeton Facility 109 Voyageur s 320 0.3

Cargill, Inc. West Fargo Plant 56 Voyageurs 311 0.2

Cavalier AFS CAFS Power Plant 234 Lostwood 280 0.8

City of Fargo Landfill 9 Voyageurs 309 <0.1

City of Minot Landfill 1 Lostwood 80 <0.1

CNH America, LLC Fargo Plant 1 Voyageurs 310 <0.1

Continental Resources Medicine Pole Hills 58 TRNP/S U 94 0.6

Dakota Gasification Co. Great Plains Synfuels 10,80 2 TRNP/NU 107 101.0

DMI Industries Fargo Plant 2 Voyageurs 321 <0.1

Grand Forks AFB Heating Plant 9 Voyageurs 342 < 0.1

Hebron Brick Company Hebron Brick Plant 30 TRNP/SU 97 0.3

Health Care Fargo Incinerator 4 Voyageurs 313 <0.1

Hess Corporation Hawkeye Comp. Station 116 Lostwood 53 2.2

Hess Corporation Tioga Gas Plant 3,655 Lostwood 35 104.4

Hillsboro MEU Hillsboro 1 Voyageurs 318 <0.1

Idahoan Foods Grand Forks Plant 104 Voyageurs 316 0 .3

J.R. Simplot Grand Forks Plant 53 Voyageurs 317 0.2180

Permittee Plant SO 2 + NO

x 2000-2004 Average (tons) Nearest

Class I Area Distance

to Nearest

Class I Area (km) Nearest

Q/D (tons/km)

Jahner Sanitation Landfill 1 Voyageurs 340 <0.1

Kaneb Pipeline Co. Jamestown Plant 1 TRNP/SU 351 <0 .1

LM Glasfiber Grand Forks Plant 1 Voyageurs 325 <0.1

Minn-Dak Farmers Coop Wahpeton Facility 601 Voyageu rs 319 1.9

Minot AFB Heating Plant 24 Lostwood 79 0.3

MDU Company Heskett Plant Unit 1 1,269 TRNP/SU 182 7.0

MDU Company Heskett Plant Unit 2 3,411 TRNP/SU 182 18.7

Mor Tech Fab Williston Plant 1 TRNP/NU 60 <0.1

Nordic Fiberglass Devils Lake Plant 1 TRNP/NU 335 < 0.1

NDSU Heating Plant 500 Voyageurs 310 1.6

Northern Border Pipeline Comp. Station No. 4 188 TR NP/NU 18 10.4

Northern Border Pipeline Comp. Station No. 5 104 TR NP/NU 56 1.9

Northern Border Pipeline Comp. Station No. 6 101 TR NP/SU 116 0.9

Northern Border Pipeline Comp. Station No. 7 104 TR NP/SU 190 0.5

Northern Border Pipeline Comp. Station No. 8 108 TR NP/SU 282 0.4

Northern Sun ADM Enderlin Facility 105 Voyageurs 33 5 0.3

Otter Tail Power Company Coyote Station 27,804 TRNP /NU 112 248.3

Petro-Hunt Little Knife Gas Plant 422 TRNP/NU 39 10 .8

Red Trail Energy Richardton Ethanol Plant 329 TRNP/ SU 74 4.4

Tesoro Mandan Refinery 5,757 TRNP/SU 182 31.6

UND Heating Plant 868 Voyageurs 318 2.7

Whiting Oil & Gas Wabek Station 73 Lostwood 71 1.0

WBI Pipeline Company Dickinson Comp. Station 137 TR NP/SU 39 3.5

WBI Pipeline Company Glen Ullin Comp. Station 67 TR NP/SU 116 0.6

Wil Rich, Inc. Wahpeton Plant 1 Voyageurs 317 <0.1

The Northern Border Pipeline Company Compressor Sta tion No. 4 is powered by a natural gas turbine. In 2005, Northern Border replaced this tu rbine with a lower emitting turbine. From 2006-2008, the average nitrogen oxides plus sulfur dioxide emissions were 118 tons per year for a Q/D of 6.6. Because of the installation of the l ower emitting turbine, this facility was

eliminated from consideration of additional control s during this planning period.

The Tesoro Refining and Marketing Company’s Mandan Refinery is subject to a Consent Decree which requires substantial emissions reductions. S ince the baseline period, Tesoro has installed

a wet scrubber and wet ESP to control sulfur dioxid e emissions from the catalytic cracking unit,181

installed new lower emitting furnaces at the alkyla tion unit and are installing low NO

x burners in the boilers. From 2006-2008, the total sulfur diox ide and nitrogen oxides emissions from the facility averaged 1,438 tons per year for a Q/D of 7.9. This ratio is expected to decline significantly when the modifications to the boilers are brought on-line. Because of these changes, this facility was not considered for addit ional controls during this planning period.

Since the baseline period, Bear Paw Energy has been injecting the acid gas into deep wells at their Grasslands and Lignite Gas Plants. This inje ction eliminates all sulfur dioxide emissions except for those emissions due to a malfunction of the injection equipment. When a malfunction occurs, the acid gas goes to a flare which will emi t sulfur dioxide. In 2007, total emissions of sulfur dioxide and nitrogen oxides (including malfu nctions) from the Grasslands Gas Plant were 274 tons for a Q/D of 9.8. Without malfunction emi ssions, the total was 52 tons for a Q/D of 1.4. At the Lignite Gas Plant, the 2007 total sulf ur dioxide and nitrogen oxides emissions (including malfunctions) were 121 tons for a Q/D of 8.1. Without malfunction emissions, the total was 48 tons for a Q/D of 3.2. These malfunct ions are generally unplanned, short durationepisodes (a few hours) with very high SO 2 emission rates that vary from year-to-year. Controlling emissions during these malfunctions is not feasible and the acid gas is flared to prevent the release of high concentrations of hydro gen sulfide. These two sources were eliminated based on their change to acid gas inject ion which greatly reduces sulfur dioxide emissions. The requirement to inject their acid ga s is included in the Title V Permit to Operate for each facility.

Petro Hunt’s Little Knife Gas Plant emissions inclu de those emissions associated with

malfunctions. If the malfunction emissions are eli minated, the average sulfur dioxide and nitrogen oxides emission rate for 2000-2004 is 337. 7 tons for a Q/D of 8.7. The Little Knife Gas Plant has seen reduced operations recently due to a decline in gas volume. New oil wells that are being drilled are generally producing from the Bakk en formation which contains sweet natural gas. In 2008, SO 2 plus NO

x emissions (including malfunctions) totaled 295 ton s for a Q/D of

7.6. Because of the small amount of emissions and the expected decline in the future, the Little

Knife Gas Plant was eliminated from consideration f or additional control during this planning period.

All of the facilities that were eliminated from con sideration for additional air pollution controls will be considered and reviewed again during future planning periods.

After review of the sources in Table 9.4, the follo wing sources in Table 9.5 were considered for additional controls during this planning period:182 Table 9.5

Sources Evaluated for Additional Control

Source Owner Unit Type Capacity

Antelope Valley Station Basin Electric Power Coop. 1 EGU 435 MWe

Antelope Valley Station Basin Electric Power Coop. 2 EGU 435 MWe

Coyote Station OtterTail Power Co. Main Boiler EGU 450 MW e

Great Plains Synfuels Plant Dakota Gasification Co. Boilers A , B & S Industrial Boilers 763 x 10 6

Btu/hr each

Tioga Gas Plant Hess Corp. 3 Sulfur Recovery Unit 225 LT PD

Tioga Gas Plant Hess Corp. C1-A to F Compressor Engines 1920-2350

BHp each

Step 2: Identify the Design Parameters for Emissio n Controls

All of the source units identified for possible add itional air pollutant control are equipped with varying degrees of air pollution control equipment, as shown in Table 9.6.

Table 9.6 Remaining Sources Existing Conditions

Source Pollutant Control Equipment Current a

Emission Rate Current a

Control Efficiency (%)

AVS 1 SO 2

NO

x Spray Dryer

OFA 0.36 lb/10 6 Btu

0.37 lb/10 6 Btu 77

-- AVS 2 SO 2

NO

x Spray Dryer

OFA 0.38 lb/10 6 Btu

0.34 lb/10 6 Btu 76

-- Coyote SO 2

NO

x Spray Dryer

None 0.71 lb/10 6 Btu

0.68 lb/10 6 Btu 66

-- Tioga Gas Plant

SRU

Engines SO 2

NO

x 3 Stage Claus

+4 bed Cold Bed

Absorber

None 1097 tpy

1353 98.8

-- GPSP - Boilers SO 2

NO

x Wet Scrubber

None 2169 tpy

0.5 lb/10 6 Btu b 96-97

--

a Based on 2005-2007 data

b Based on 2007 data183

Work is currently underway to increase the efficien cy of the spray dryers at AVS I and II. This work is being done because of an expected increase in the sulfur content of the coal used at the facilities. The increase in efficiency is expected to approach 90% which the Department considers the limit of spray dryer efficiency. Eve n though the efficiency will be increased, no reduction in emissions is expected because of the h igher sulfur coal. Because upgrades of the spray dryers are already in progress, this option w as not considered at AVS I or II during this planning period. At the Coyote Station, upgrades t o the spray dryer would require a detailed engineering analysis to determine if improvements a re possible. For this planning period, replacing the spray dryer is evaluated. Any upgrad es to the spray dryer (if possible) will produce less emissions reductions and less visibility impro vement when compared to a new wet scrubber. This source will also be reevaluated during future planning periods to determine if additional

controls are reasonable.

The boilers at the Great Plains Synfuels Plant (GPS P) are equipped with an ammonia reagent wet scrubbing system followed by a wet electrostatic pr ecipitator. This system is achieving 96-97% removal of sulfur dioxide from the flue gas. This removal efficiency is comparable to BACT or

BART for industrial boilers of this size. Therefor e, sulfur dioxide controls for these boilers were not evaluated further during this planning period.

The following control options were reviewed for pos sible implementation at the remaining

sources:

Table 9.7 Control Options Evaluated

Source Pollutant Control

Considered Estimated Control Efficiency (%)

AVS 1 and 2 SO 2 New Wet Scrubber 95

NO

x LNB

SNCR

SCR w/Reheat 30-75

30-75

40-90 c
Coyote SO 2 New Wet Scrubber 95

NO

x ASOFA

SNCR

ASOFA + SNCR

SCR w/Reheat 40

30

50-60

40-90 c
Tioga Gas Plant

SRU

1920 BHp Engines SO 2 Tail Gas Cleanup 99.8-99.98 a

NO

x SCR

Engine Remanufacture

Air-Fuel Ratio Controller Ignition Timing Retard 80-90 c

80-90

10-40

15-30 2350 BHp Engines NO

x SCR 33-67

GPSP – Boilers NO

x SNCR b

SCR b 30-40

40-90 c184

a Overall efficiency of the sulfur recovery unit and tail gas cleanup unit. BACT determinations range from 99.8% for existing units to 99.98% for n ew units.

b The Department has concerns whether SCR and SNCR ar e technically feasible for the GPSP (see DGC’s comments in Appendix I).

c The Department considers 90% efficiency reasonable for new installations and 80% reasonable

for retrofits.

Step 3: Develop Cost Estimates Based on the Design Parameters

The available control options were evaluated by WRA P’s contractor EC/R Incorporated. The report on this evaluation is found in Appendix I.1. The cost for the wet scrubber at the Coyote Station was adjusted to represent the gross capacit y of the facility (450 MWe vs 427 MWe) which is larger than EC/R evaluated. Also, the rem oval efficiency for a new wet scrubber was adjusted from 90% to 95%. The costs associated wit h the various control technologies are

shown in Table 9.8.

The cost effectiveness ($/ton) for new scrubbers at AVS I & II and Coyote Station is higher than at the BART sources that are not equipped with scru bbers. Because AVS and Coyote Station are already equipped with spray dryers, the cost effect iveness is higher because less sulfur dioxide

will be removed than at the unit without a scrubber . The following control options were found to

have an excessive cost effectiveness:

AVS 1 & 2 – Wet scrubber; SCR w/reheat; and LNB + S CR w/reheat Coyote – SCR w/reheat and ASOFA + SCR w/reheat Tioga Gas Plant – Tail Gas Cleanup

DGC – SNCR and SCR

The SRU at the Tioga Gas Plant is currently operati ng at less than 45% of its rated capacity. It is expected that the amount of sulfur recovered and em issions from the tail gas incinerator will continue to decline due to a decline in sour gas pr oduction in the area the Tioga Gas Plant serves. Most new gas produced comes from the Bakken formati on which is sweet gas.

The Department has concerns whether SCR or SNCR can be successfully applied at the GPSP (see DGC comments in Appendix I). Pilot scale test ing may be necessary to determine the technical feasibility of SCR or SNCR for the boiler s which produce a flue gas with a high carbon

dioxide and sulfur concentration.

Therefore, these control technologies were not eval uated further.

For the most efficient control options for which th e cost effectiveness (as described in Table 9.8) was considered reasonable on a $/ton basis, the 201 8 projected emissions were modeled by the NDDoH to determine the source-specific improvement in visibility. Cumulative modeling was conducted using the procedures (default EPA methodo logy), hybrid modeling system, and baseline and future (2018) emissions inventories as described in Section 8.5. The185Table 9.8Control Options CostSourceUnitPollutantControl TechnologyTotalAnnualized Cost($)ControlEfficiency(%)EmissionsReduction(tpy)CostEffectiveness($/ton)AVS 1 SO2NOxNew Wet ScrubberLNBSNCRLNB+SNCRSCR w/reheat1LNB + SCR w/reheat32,170,0002,280,0008,960,00011,240,00044-63.2 million46.3-65.5 million9551406580906,7803,8893,0504,9566,1006,8634,7455862,9382,2687,213-10,3606,746-9,544AVS 2 SO2NOxNew Wet ScrubberLNBSNCRLNB+SNCRSCR w/reheat1LNB + SCR w/reheat32,170,002,280,0008,960,00011,240,00044-63.2 million46.3-65.5 million9551406580905,8993,4502,7064,3975,4116,0875,4536613,3112,5568,132-11,6807,606-10,761Coyote 1 SO2NOxNew Wet ScrubberASOFA1SNCRASOFA & SNCR1SCR w/reheat1ASOFA + SCR w/reheat33,280,0001,284,0008,520,00011,245,00045.3-65.1 million46.6-66.4 million95404055809012,8355,2235,2237,18210,44611,7522,5932461,6311,5664,337-6,2323,965-5,650Tioga Gas Plant3SRU1920 Hp Engines2350 Hp EnginesSO2NOxTail Gas Clean Up2Air Fuel Ratio ControllerIgnition Timing RetardLEC RetrofitSCRSCR5,800,000260,000140,000560,0001,600,000500,00099.825228580501,0183052681,035974345,6978525225411,6431,471DGC Boilers (each) SNCRSCR1,690,0005,505,00030802596706,5258,216Notes: A) The Department does not consider highdust SCR to be technically feasible for North Dakota lignite (see BART analysis in Section 7). Theuncertainties associated with designing an SCR system because of the high sodium and potassium submicron aerosols in the flue gas, even afterthe air pollution control equipment, dictates the use of the high end of the SCR cost range.B) Replacement of the compressor engines with electric motors is not technically feasible since the compressor cylinder connecting rods are anintegral part of the engines crankshaft.1Based on BART cost estimate for Leland Olds Unit 2and Minnkota 1 & 2 shared cost estimate.2Based on an overall efficiency of the SRU and tailgas cleanup unit of 99.8%.3Reductions are the total for all engines with the specified horsepower rating.future emissions inventory was modified to reflect the control technology for each candidate

source (A VS 1 EGU, A VS 2 EGU, Coyote EGU, and Tioga Gas Plant), and modeling was conducted using the revised future inventory for one source at a time. The reasonable progress goals in 40 CFR 51.308(d)(1) requires improvement in the most impaired days. The most impaired days are defined in 40 CFR 51.301 as the average visibility impairment for the twenty
percent days with the highest amount of visibility impairment. Therefore, modeling addressed

the 20% worst days for both TRNP and 

### L W A Class I areas. The results for each candidate

source were compared with the results using the unmodified future emissions inventory (Table
8.11) to determine the additional visibility improvement due to the tested control technology.

Modeled visibility improvement, for each candidate sourceltechnology, is provided in Table 9.9.

The single source controlled emissions (modeled tons per year) and annualized cost effectiveness (dollars per deciview) are also reported in the table. Reported visibility improvement (in deciviews) reflects the higher value for either TRNP or 

### L W A. Note that visibility improvement reported for Coyote represents the total for both S02 and NO
x control technologies, and the improvement reported for the Tioga Gas Plant represents the total for all 1920 and 2350 horsepower engines. As shown in the table, predicted visibility improvement is very marginal

for all candidate sources/technologies, and consequently cost per deciview is very high

.

.'

Table 9.9 Visibility Improvement and Cost Effectiveness



## , Visibility Visibility 

### I

Improvement

. 

# I I Improvement 

### I (%\*",. Emissions I (dv)* Control

I (TPY)

Source Pollutant TRNP LWA

AVSI**Technolo~** TRNP LWA

0.01 0.05

AVS2 0.005 0.03 LNB+SNCR 2358 NO. 0.Q3 0.01 0.05 Coyote LNB+SNCR 2144 0.005 NOlL
0.20 0.04 1,924 0.02 0.11 Wet Scrubber S02

I ASOFA+SNCR 5,871 TiogaG.P.

1920 BHp Engines 

## i NO. NO.

0.26

. 2350 BHp Engines NO. 0.05 0 268 0 LEC Retrofit 33 SCR Cost

Effectiveness

($fdv)**
1,124,000,000
1,124,000,000
1,113,000,000

21,200,000

*The less efficient technologies evaluated would provide less improvement.

**Based on the maximum visibility improvement (per source) at any Class I area in North

Dakota.

* * *Improvement (%) from baseline conditions.



### Time Necessary for Compliance

Up to 6.5 years after SIP approval is necessary to achieve compliance (see EC/R report in Appendix 1.1). Additional time may be necessary if normal maintenance outages do not coincide

with the projected schedule. It is anticipated that all required changes could be implemented by

2018 depending on the date of approval of this SIP. It is not anticipated that any of the remaining sources will be retired prior to 2018.

186187



### Energy and Non-Air Impacts

All of the control technologies for the various sou rces will consume energy (see EC/R report in Appendix I.1). In the case of the Antelope Valley Station and the Coyote Station, this would mean less electricity available for sale. The enha ncement of the sulfur dioxide scrubbing system at the Coyote Station would increase the amount of solid waste generated (ash/CaSO 4 ) which must be handled and properly disposed. However, th ere are no non-air impacts identified that would preclude additional reductions of SO 2 or NO

x from the facilities.



### Remaining Useful Life of the Source

The following table lists the expected remaining us eful life of the remaining sources.

Table 9.10 Remaining Useful Life

Source Unit Startup

Date Estimated

Remaining

Useful Life (yrs)

AVS Unit 1

Unit 2 1983

1985 20-40

20-40

Coyote Unit 1 1981 20-40

Tioga Gas Plant Engines 1954 5-40

The engines at the Tioga Gas Plant are now 55 years old. Engines D and F have recently been refurbished. It is expected that the other engines could be refurbished which will extend their remaining useful life an indefinite period. Other than the engines at the Tioga Gas Plant, the remaining useful life of the affected sources would not preclude additional air pollution controls.188



### Reasonable Progress Goals - Required Controls for P oint Sources

EPA has stated in their Guidance for Setting Reason able Progress Goals Under the Regional Haze Program (June 1, 2007) “in assessing additiona l emissions reduction strategies for source categories or individual, large scale sources, simp le cost effectiveness based on a dollar-per-ton calculation may not be as meaningful as a dollar pe r deciview calculation.” It has been determined that requiring additional controls, beyo nd BART, on existing point sources will not substantially improve visibility in the Class I Fed eral Areas. The maximum combined improvement based on the Department’s cumulative mo deling for the average of the 20% worst days is 0.11 deciviews at LWA and 0.03 deciviews at TRNP for the most efficient control options for each source that is cost effective. Th is amounts to a 0.17% improvement at TRNP over the baseline condition for the most impaired d ays and 0.56% improvement at LWA. Other less efficient control technology options would pro vide substantially less visibility improvement in the Class I areas. The total capital cost to ach ieve this improvement is approximately 243 million dollars with an annualized cost of approxim ately 68 million dollars. Based on the data in Tables 9.8 and 9.9, the cost effectiveness is over 618 million dollars per deciview of improvement at LWA and 2.3 billion dollars per deci view at TRNP. For all sources evaluated individually and cumulatively, the cost ($/dv) is c onsidered excessive. Therefore, no additional controls are proposed for these non-BART sources du ring this planning period. However, conditions at the plants and control technologies m ay change in the future. Therefore, all of these sources will be reevaluated during future pla nning periods.



### 9.5.2 Agricultural Tillage Operations

North Dakota has approximately 38 million acres of farm and ranch land or approximately 86% of the State’s area. Working the land can contribu te significant amounts of fugitive and

windblown dust. The WRAP has estimated that emissi on sources in North Dakota put more than 420,000 tons of particulate matter into the atmosph ere in 2002. Fugitive dust from agricultural

activities and windblown dust from farm fields were a major contributor to these emissions. Although there was a large amount of particulate ma tter emissions, the effect on visibility in the North Dakota Class I areas was small, but not insig nificant, as shown in Figures 9.1 and 9.2 from the WRAP’s TSS. At TRNP, coarse mass and soil (fin e mass) combined to contribute approximately 11% of the total extinction during th e 20% worst days of the baseline period. At the Lostwood Wilderness Area, approximately 7% of t he total extinction was due to coarse mass and soil. North Dakota sources contributed approxi mately 45 percent of the PMF and PMC at TRNP and approximately 30 percent at LWA during the 20 percent worst days in 2000-2004 (based on WRAP’s weighted emissions potential analy sis).189 Figure 9.2 TRNP Species Apportionment 20% Worst Days

Figure 9.3 LWA Species Apportionment 20% Worst Days

The practice of conservation tillage is becoming mo re popular in North Dakota. The Conservation Technology Information Center (CTIC) i n West Lafayette, Indiana specifies that 30 percent or more of crop residue must be left aft er planting to qualify as a conservation tillage system. Some specific types of conservation tillag e include Minimum Tillage, Zone Tillage, Notill, Ridge-till, Mulch-till, Reduced-till, Strip-t ill, Rotational Tillage and Crop Residue Management. According to the Crop Residue Manageme nt survey conducted by the CTIC, total conservation tillage in North Dakota increased from 28% to 39% of total planted acres from 1998 to 2004. In general, conservation tillage pra ctices are used more in the western part of the190

State (near the Class I areas) than in the eastern part of the State due to the more arid conditions, thinner topsoil and the types of crops grown. In 2 006, 77% of the crop acreage in Williams County in Western North Dakota was planted using co nservation tillage practices versus 28% in Sargent County (southeastern North Dakota). It is expected that conservation tillage practices will increase over the planning period. Higher fue l, equipment and labor costs will entice farmers to reduce tillage. Other added benefits in clude better soil moisture storage and eventually less fertilizer usage. Additionally, co nservation tillage practices, such as No-till farming, help sequester carbon which can be sold as carbon credits. As carbon dioxide controls are instituted, the money earned by farmers for car bon sequestration will also provide an incentive for conservation tillage practices.

Given the small contribution of coarse mass and soi l to total extinction and that conservation tillage practices are increasing, the Department co ncludes there is no need to implement controls on farming practices. As outlined earlier, free ma rket incentives should increase conservation tillage which will reduce emissions. The trend of increased conservation tillage practices from 1998-2004 is expected to continue during the planni ng period.

Sources in this category are subject to NDAC 33-15- 17-02.6 which requires agricultural activities be managed in a manner as to minimize du st from becoming airborne. The Department will reevaluate the source category in future plann ing periods to determine if additional controls are required.



### 9.5.3 Smoke Management for Agricultural, Forest Man agement and Prescribed Burning

It has been determined that no additional rules or controls for smoke management are required (see Section 10.6.5). The worst short-term visibil ity degradation that occurs in the Class I areas is caused by prescribed burning conducted by the Fe deral Land Managers. In 2005, the entire LWA (5,577 acres) was burned by the FLM. In additi on, 3,579 acres in the immediately adjacent Lostwood Wildlife Refuge were burned on 7 different days. Although the State of North Dakota recognizes the position of the FLMs th at prescribed burning is necessary to maintain a healthy ecosystem, it must also be recog nized that the actions of the FLMs that affect visibility in the Class I areas must be considered when evaluating controls for others that use prescribed burning (e.g., farming, road maintenance , etc). No additional smoke management requirements are proposed in this planning period. However, the Department will reevaluate this source category during future planning periods to d etermine if additional regulation is required.



### 9.5.4 Reserved

9.5.5 Oil and Gas Exploration and Production

Oil and natural gas production in North Dakota is g enerally limited to the western one-third of the State. In September 2009, there were 4,348 ope rating wells that produced approximately 238,000 barrels of oil per day. This is in contras t to states like Wyoming that has approximately191

45,000 producing oil and gas wells and Colorado whi ch has approximately 40,000 active wells. The primary difference is that North Dakota does no t have any coal bed methane (CBM) wells. The lack of CBM wells means there are much fewer pu mps, compressors and gas processing plants needed even though North Dakota produces mor e oil than either of these states. The

baseline SO 2 and NO

x emissions from area oil and gas sources are estima ted at less than 5000 tons per year of each pollutant (see Table 6.1).

North Dakota’s oil production is highly dependent o n the price of oil. Several peaks in production (i.e. 1996 and 1983) have been achieved only for production to drop severely (i.e. 42% from 1983 to 2003) and then increase as the pri ce of oil increases. Several projections have been made regarding the amount of oil that will be produced in the future, the number of wells that will be producing and the number of drilling r igs that will operate in the State. All of these projections are highly speculative because of the v olatility of oil prices. The price of North Dakota crude oil reached a high of approximately $1 27 per barrel in 2008 and dropped to as low as $25 per barrel in 2009. The number of drilling rigs also dropped dramatically from a high of 92 in November 2008 to 35 in May 2009. WRAP has pr ojected a 4-5 fold increase in NO

x emissions from oil and gas activities by 2018. Alt hough emissions may increase this amount during the planning period, the North Dakota Oil an d Gas Division of the State Industrial Commission believes that emissions will decrease by 2018 to a level that is 2.0 to 2.5 times the

baseline emission rate. The Oil and Gas Division b elieves that activity associated with the major oil producing formation (Bakken formation) will be decreasing by 2018 with a peak during this planning period. However, any estimate of future a ctivity is suspect because the future of oil prices is unknown. Because current estimates of fu ture oil and gas activity, and emissions from that activity, are very questionable, the Independe nt Petroleum Association of Mountain States (IPAMS) is sponsoring development of a third, or Ph ase III, inventory of emissions from the Williston Basin in North Dakota. This inventory is not complete and available for this planning period. Because of the serious flaws in the Phase I and Phase II inventories, the Department believes that the Phase III inventory is necessary for any planning activities for oil and gas

emissions in North Dakota.

A Q/D type analysis does not work well for oil expl oration or production facilities. These individual facilities generally have very low sulfu r dioxide and nitrogen oxides emissions. However, when the facilities emissions are aggregat ed, there may be significant impact on visibility in a Class I area. The Q/D analysis in 9.5.1 included the larger compressor stations and natural gas processing plants (sources subject to T itle V). North Dakota also permits minor oil and gas sources including small compressor stations (greater than 500 Hp), natural gas processing plants and tank batteries. The Q/D anal ysis indicates that only the larger facilities (i.e. larger Title V sources) have a significant im pact on visibility in North Dakota Class I areas. Sulfur dioxide emissions from future oil and gas ac tivities are not a concern because most new oil and gas production is from the Bakken formation which contains sweet (negligible sulfur content) oil and gas. In addition, engines will be required by Federal rule to use ultra low sulfur gasoline and diesel fuel. Nitrogen oxides emission s are the primary concern. These will emanate from vehicles, drilling rig engines, glycol dehydrators, flares, compressor engines, and other combustion sources. Stationary engines are s ubject to a number of New Source Performance Standards (NSPS) and Maximum Achievable Control Technology (MACT) standards which will help limit NO

x emissions. The EPA has also promulgated a 1-hour192

NAAQS for NO 2 . North Dakota had a 1-hour NO 2 AAQS set at 100 ppb until December of 1994. The new NAAQS is slightly more stringent tha n the former SAAQS for NO 2 . The Department’s experience indicates that oil and gas facilities will have to limit NO

x emissions through the use of control devices such as catalyti c convertors on engines or low NO

x burners at heater/treaters or glycol dehydration unit boilers. Particulate emissions from oil and development and production are not expected to chan ge appreciably from the baseline emission rate. Emissions from the production site are mostl y from development of the well pad which is

of short duration. Vehicle traffic would be the on ly other significant source of particulate matter emissions. Once the well is developed, these emiss ions should decrease substantially.

The WRAP, through its contractor EC/R Incorporated, has prepared an analysis of the four factors for reasonable progress for oil and gas exp loration and production operations (see Appendix I.2, Section 4). Given the small amount o f baseline emissions and the uncertainty of the projection of future emissions, the Department proposes no additional controls for oil and gas exploration and production facilities at this time. The Department will continue to track oil and gas emissions and will take into consideration the Phase III inventory when it is available. During the mid planning period review, the Departme nt will review oil and gas emissions and take action if necessary. Oil and gas emissions wi ll also be addressed during subsequent planning periods.



### 9.6 Visibility Modeling and Weight of Evidence

As detailed in Section 8, modeling has been conduct ed by both WRAP and the NDDoH to estimate visibility improvement resulting from impl ementation of BART and other reasonable control measures. Modeling addressed TRNP and LWA Class I areas in North Dakota. Visibility improvement modeling accounted for the c umulative effect of BART controls, and other growth and control factors. Modeling was ini tially conducted using the default EPA methodology, and results were compared with the def ault EPA uniform rate of progress (URP). Because results based on the default EPA methodolog y did not achieve compliance with default URP targets for 2018, additional modeling was condu cted by the NDDoH for various weight of evidence options.

Supplemental weight of evidence modeling analyses c onducted by the NDDoH, which have a bearing on the selection of reasonable progress goa ls, include the following.

1) Discounted the impact of international (in this case, Canadian) source visibility-affecting

emissions on North Dakota Class I areas.

2) Discounted the impact of visibility-affecting em issions from all sources located outside of North Dakota, on North Dakota Class I areas.

3) Used the complete emissions inventory for the de fault EPA method, but zeroed out future

SO 2 and NO X emissions from all sources located in North Dakota (i.e., assumed 100 percent future control of all SO 2 and NO X emissions in North Dakota), to determine progress with respect to the default glide path for North Dakota Class I areas.193

4) Conducted modeling to determine the incremental visibility improvement, and cost effectiveness ($/dv), of enhanced control technolog y at AVS generating station, Coyote generating station, and Tioga Gas Plant (Section 9. 5.1).

Modeling results for the default EPA methodology an d weight of evidence analyses are summarized in Table 9.11. In the table, Scenarios 1 and 2 represent the implementation of default EPA methodology by WRAP and NDDoH, respecti vely. Scenarios 3, 4, and 5 reflect the first three NDDoH weight of evidence analyses outli ned above. Results for the fourth weight of evidence analysis (above) were provided in Table 9. 9. Results in Table 9.11 are presented as the projected percent of the 2018 target.

From results of visibility modeling based on standa rd EPA methodology, and results of the weight of evidence analyses, the following conclusi ons are applicable to the establishment of reasonable progress goals for North Dakota Class I areas.

1) The uniform rate of progress goal for 2018 for 2 0% worst days will not be achieved at

either TRNP or LWA.

2) Apportionment modeling results indicate the cont ribution of sources located outside of North Dakota is much greater than the contribution of in-state sources to 20% worst day visibility at TRNP and LWA (both baseline and 2018)

.

3) Though the addition of proposed BART controls su bstantially decreases the visibility impact of North Dakota EGUs, these EGUs comprise on ly a small component of total 20% worst day impact at TRNP and LWA.

Table 9.11 NDDoH Visibility Modeling Results 20% Worst Days EPA Methodology and Weight of Evidence Analysis Sum mary

Scenario Description Class I Area Projected

Percent of 2018 Target 1 WRAP CMAQ

Default EPA Methodology TRNP

LWA 24.0

16.7 2 NDDoH Hybrid

Default EPA Methodology TRNP

LWA 38.1

26.7 3 NDDoH Hybrid

Canada Sources Discounted TRNP

LWA 50.0

40.2 4 NDDoH Hybrid

All Sources Other Than ND Discounted TRNP

LWA 83.9

59.6194

Scenario Description Class I Area Projected

Percent of 2018 Target 5 NDDoH Hybrid

Base Emission Inv = Default

Future Emissions Inv = All ND

SO 2 and NO

x Emissions set to zero TRNP

LWA 83.8

72.6

4) Compliance with 20% worst day URP 2018 targets a t North Dakota Class I areas cannot be achieved through additional emissions reductions from North Dakota sources, alone. It will require significant additional visibility a ffecting emissions reductions from Canada, other western states and from sources locat ed outside of the WRAP CMAQ modeling domain.

5) After discounting the impact of Canadian sources , significantly greater progress (50 percent greater) was demonstrated, relative to URP 2018 targets for North Dakota Class I areas, than modeling with the entire emissions inve ntory but the 20% worst day targets

were still not achieved.

6) After discounting the impact of all sources located outside of North Dakota , even greater progress was demonstrated, relative to URP 2018 tar gets for North Dakota Class I areas, than modeling with Canadian sources discounted. Ho wever, 20% worst day targets were

still not achieved.

7) After zeroing out all future SO 2 and NO X emissions in North Dakota under default EPA methodology (emulating a 100 percent, unrealistic c ontrol of all sources), compliance with 20% worst day targets was still not achieved a t North Dakota Class I areas.

8) The use of enhanced control technology at AVS ge nerating station, Coyote generating station, and Tioga Gas Plant provides minimal incre mental improvement in 2018 visibility (Table 9.9), and does not meaningfully c hange status with respect to 2018 visibility goals.

Given these conclusions based on modeling, it appea rs most of the visibility impact at North

Dakota Class I areas is due to emissions from sourc es located outside the jurisdiction of the NDDoH. But regardless of the extent to which visib ility-affecting sources located outside of North Dakota are discounted, compliance with URP ta rgets cannot be achieved. Further, the use of enhanced control technology on additional candid ate sources (Item 8, above) within jurisdiction of the NDDoH does not provide a meanin gful improvement in terms of 2018 URP visibility goals. It is not realistic to expect si gnificant additional controls (beyond BART or other current controls) will be implemented in stat es or Canadian provinces apart from North Dakota before 2018. From a modeling perspective, t herefore, setting reasonable progress goals for 20% worst days to be consistent with 2018 model ing results for the default EPA methodology (Table 9.11) would seem most realistic.195



### 9.7 Establish Reasonable Progress Goals

As indicated in Section 8, control of emissions fro m North Dakota sources has only a small effect on visibility conditions in the North Dakota Class I areas. The source apportionment (based on WRAP modeling) for the 20% worst days in the Class I areas indicates that sources

outside of North Dakota contribute from 79-87% of t he sulfate or nitrate which cause the greatest visibility impairment in the North Dakota Class I a reas. The source region apportionment provided by WRAP is presented in Table 9.12 for the North Dakota Class I areas. Note that the

WRAP modeled contributions for North Dakota sources in Table 9.12 are somewhat smaller than the contributions based on NDDoH modeling in Table 8.16. This is because the NDDoH approach incorporated a more realistic representati on of point source plumes, resulting in higher predictions for North Dakota sources (and greater v isibility improvement).

Table 9.12 Source Region Apportionment 20% Worst Days

Contributing

Area Class I Area

TRNP LWA

SO 4 NO 3 SO 4 NO 3 North Dakota 21.1% 19.1% 17.9% 13.0%

Canada 28.3% 31.8% 45.9% 44.6%

Outside Domain 32.6% 17.9% 20.2% 14.0%

Montana 3.1% 15.0% 2.4% 9.3%

CENRAP 4.9% 2.5% 5.3% 5.1%

Other 10.5% 13.7% 8.3% 14.0%

An analysis was conducted to determine if the unifo rm rate of progress could be achieved in the North Dakota Class I areas by controlling sulfur di oxide and nitrogen oxides emissions from instate sources (see Section 8.7.3.3). The results i ndicate the uniform rate of progress cannot be achieved by reductions in North Dakota alone. If a ll sulfur dioxide and nitrogen oxides emissions in North Dakota were completely controlle d (zero emissions), only 72.6% of the uniform rate of progress for the 20% worst days wou ld be achieved at LWA and only 83.8% at TRNP. Significant reductions of emissions from sou rces outside of North Dakota will be required in order to meet the uniform rate of progr ess for this planning period.

North Dakota can only require emission controls for sources within its boundaries. Because of the large contribution to visibility impairment fro m sources outside of North Dakota, any estimate of reasonable progress on a deciview basis is tenuous at best. Any increase in emissions

from sources external to North Dakota could offset any improvement from the reduction of emissions at in-state sources. By 2018, North Dako ta BART controls plus other regulatory requirements are expected to reduce in-state SO 2 emissions by more than 60% and NO

x emissions by more than 25%. Table 9.13 shows the p rojected change in emissions for North Dakota as well as surrounding states and Canada.196 Table 9.13 Projected Change in Emissions

2002-2018 (%)

South

Dakota Montana Minnesota Canada North

Dakota

SO 2 -35.7 -11.8 -28.8 -6.8 -60.0

NO

x -17.9 -26.0 -39.4 -0.8 -25.3

OC -6.1 -3.3 -5.3 22.7 -19.4

EC -51.1 -16.6 -28.9 75.2 -52.3

PMF 2.2 7.5 -1.3 34.8 2.0

PMC 4.2 8.8 -4.4 33.8 3.5

NH 3 0.3 1.2 33.9 -31.9 -0.3

VOC -0.5 -0.6 2.9 -1.2 1.1

CO -17.0 -15.9 -20.8 -11.7 -27.4

Note: Based on WRAP’s Case Plans 02d and PRP18b.

The reasonable progress goals based on the Departme nt’s hybrid modeling approach in Table 9.14 are established. The analyses conducted indic ate there will be no degradation in the 20% best days. The Department’s modeling results show that visibility in the 20% best days will improve 0.14 deciviews at TRNP and 0.09 deciviews a t LWA.

Table 9.14 Reasonable Progress Goals

Class I Area Baseline Visibility

20% Worst Days (dv) 2018 RPG a

20% Worst Days (dv) 2018 RPG b

20% Worst Days (dv)

TRNP 17.8 16.9 17.2

LWA 19.6 18.9 19.1

a Based on Department’s hybrid modeling approach.

b Based on WRAP’s modeling approach.

40 CFR 51.308(d)(1)(ii) requires the State to provi de for public review an assessment of the number of years it would take to attain natural con ditions if visibility improvement continues at the rate of progress selected by the State as reaso nable. Achieving natural conditions will require the elimination of all anthropogenic sources of emi ssions. Given current technology, achieving natural conditions is an impossibility. Any estima te of the number of years necessary to achieve197

natural visibility conditions would require assumpt ions about future energy sources, technology improvements for sources of emissions, and every fa cet of human behavior that causes visibility impairing emissions. The elimination of all SO 2 and NO

x emissions in North Dakota will not achieve the uniform rate of progress for this, or a ny future planning period. Any estimate of the number of years to achieve natural conditions is qu estionable because of the influence of out-ofstate sources. The number of years required to ach ieve natural conditions based on the proposed reasonable goals are as follows:

Table 9.15

Time Necessary to Achieve Natural Conditions

Class I Area Baseline Visibility Natural

Visibility Improvement

Rate this Planning

Period Years to Natural

Conditions a

20% Worst Days (dv) 20% Worst

Days (dv) 20% Worst

Days (dv/yr) 20% Worst

Days

TRNP 17.8 7.8 0.06429 156

LWA 19.6 8.0 0.05000 232

a Based on the Department’s hybrid modeling approach.

If the most efficient cost effective control option s evaluated for Coyote Station, Antelope Valley Station and the Tioga Gas Plant were implemented, t he number of years to reach natural conditions would be 151 years at the three units of TRNP and 201 years at LWA. Implementing additional controls at these sources will not signi ficantly affect current visibility conditions or th e amount of time necessary to achieve natural conditi ons.198



## 10. Long -Term Strategy

10.1 Long -Term Strategy Requirements

40 CFR 51.308(d)(3) contains the requirements for t he long-term strategy for regional haze. Each State listed in §51.300(b)(3) must submit a lo ng-term strategy that addresses regional haze visibility impairment for each mandatory Class I Fe deral area within the State and for each mandatory Class I Federal area located outside the State which may be affected by emissions from the State. The long-term strategy must include enforceable emissions limitations, compliance schedules, and other measures as necessa ry to achieve the reasonable progress goals established by States having mandatory Class I area s. In establishing its LTS for regional haze, the State must meet requirements of §51.308(d)(3)(i ) through (3)(v).



### 10.2 Consultation With Other States

40 CFR 51.308(d)(3)(i) requires “Where the State ha s emissions that are reasonably anticipated to contribute to visibility impairment in any manda tory Class I Federal area located in another State or States, the State must consult with the ot her State(s) in order to develop coordinated emission management strategies. The State must cons ult with any other State having emissions that are reasonably anticipated to contribute to vi sibility impairment in any mandatory Class I

Federal area within the State.”

North Dakota emissions are reasonably anticipated to contribute to visibility impairment in mandatory Class I Federal areas in Minnesota (Bound ary Waters Canoe Area Wilderness Area and Voyageurs National Park), Montana (Medicine Lak e National Wildlife Refuge Wilderness Area and U.L. Bend National Wildlife Refuge Wildern ess Area), and South Dakota (Badlands National Park and Wind Cave National Park). Reasona bly anticipated to contribute is considered to be a contribution of more than 5 percent to the total extinction (B ext ) in the Class I area. North Dakota emissions impacts on Michigan Class I areas (Isle Royal National Park and Seney National Wildlife Refuge Wilderness Area) are small or less than 5 percent of the extinction (B ext ). North Dakota emissions impacts on other more dis tant Class I areas are considered

minimal. See the discussion in Section 2.4.

The NDDoH has consulted with Minnesota and Michigan as a part of the Northern Class I Areas consultation group and Minnesota individually. As a result of the consultations, Minnesota sent a memorandum dated September 19, 2007 to North Dako ta and other states impacting Minnesota Class I areas. Minnesota requested a response docu menting these consultations have taken place to the satisfaction of North Dakota or detailing ar eas where additional consultation should occur.

In those states Minnesota has identified as additio nal contribution states, they asked such states to respond with their agreement or disagreement wit h Minnesota’s determination of contributing states and the additional control strategies that w ill be evaluated. Minnesota’s memorandum and the NDDoH letter of response dated August 22, 2008 are attached in Appendix J.2.199

The NDDoH has consulted with Montana and South Dako ta through the WRAP which we are members and as needed individually. Additionally th e NDDoH has consulted with EPA Region 8 in Denver concerning the Montana Class I areas as t hey are preparing a FIP at the request of the

State.

Minnesota, Montana and South Dakota are the only st ates that have emissions that are reasonably anticipated to contribute to visibility impairment in the North Dakota Class I Federal

areas.

Consultation is further addressed in Section 3, Pla n Development and Consultation.



### 10.3 Demonstration of Inclusion of Measures to Obta in RPGs in Class

I Areas

40 CFR 51.308(d)(3)(ii) requires “Where other State s cause or contribute to impairment in a mandatory Class I Federal area, the State must demo nstrate that it has included in its implementation plan all measures necessary to obtai n its share of the emission reductions needed to meet the progress goal for the area. If the Stat e has participated in a regional planning process,

the State must ensure it has included all measures needed to achieve its apportionment of emission reduction obligations agreed upon through that process.”

The control measures and emission limits incorporat ed in this SIP for the seven electrical generating units subject to BART combined with Fede ral mobile source and other rules will reduce North Dakota sulfur dioxide emissions by 60 percent, nitrogen oxide emissions by 25 percent, organic carbon emissions by 19 percent and elemental carbon emissions by 52 percent. These percent reductions compare favorably with the uniform rate of progress first planning period required overall reduction by 2018 of approx imately 23.3 percent (14 years ÷ 60 years x 100 = 23.3 percent). In addition, existing State s moke management and fugitive dust control rules will adequately control emissions from agricu ltural and forest burning and construction

activities. North Dakota has met and included in th is SIP all measures needed to achieve its apportionment of emission obligations agreed upon b y the members of WRAP. These emission reductions will provide North Dakota’s share of emi ssion reductions needed for Class I Federal areas in Minnesota, Michigan, Montana and South Dak ota.



### 10.4 Documentation of the Technical Basis for Model ing, Monitoring

and Emissions Information

40 CFR 51.308(d)(3)(iii) requires “The State must d ocument the technical basis, including modeling, monitoring and emissions information, on which the State is relying to determine its apportionment of emission reduction obligations nec essary for achieving reasonable progress in each mandatory Class I Federal area it affects. The State may meet this requirement by relying on technical analyses developed by the regional pla nning organization and approved by all State participants. The State must identify the baseline emissions inventory on which its strategies are200

based. The baseline emissions inventory year is pre sumed to be the most recent year of the consolidated periodic emissions inventory.”

North Dakota is a member of the Western Regional Ai r Partnership (WRAP) regional planning organization and relied on the modeling, monitoring and emissions information and technical analyses developed by WRAP.

The NDDoH relied on the use of CALPUFF for single s ource BART screening modeling, WRAP CMAQ and PSAT modeling, and its own hybrid CAL PUFF modeling in its cumulative impact analyses. The BART modeling conformed to the requirements of the BART guidelines and is described in Section 7. The WRAP CMAQ and P SAT modeling and the NDDoH hybrid CALPUFF modeling conformed with EPA modeling guidel ines and are described in Section 8.

The NDDOH relied on IMPROVE monitoring data as avai lable on the WRAP TSS website and

discussed in Section 4.

The NDDoH used the WRAP Plan02d emissions inventory for the baseline emissions year 2002 which reflects a composite interpretation of emissi ons for the base 2000-2004 period; and the WRAP CMAQ PRP18a (Preliminary Reasonable Progress 2 018 Scenario A) emissions inventory which reflects projected year 2018 emissi ons. Case PRP18a represents base period emissions projected to 2018, accounting for estimat es of the effect of BART controls, and assuming other growth and control factors. The Plan 02d and PRP18a emissions inventories were used in modeling and are discussed further in Secti on 8. A later Case PRP18b emissions inventory was prepared by WRAP and included in Sect ion 6, Sources of Visibility Impairment in

North Dakota Class I Areas.



### 10.5 Identification of Anthropogenic Sources of Vis ibility Impairment

40 CFR 51.308(d)(3)(iv) requires “The State must id entify all anthropogenic sources of visibility impairment considered by the State in developing it s long-term strategy. The State should consider major and minor stationary sources, mobile sources and area sources.”

The anthropogenic sources of visibility impairment are identified in Section, 6 Sources of Visibility Impairment in North Dakota Class I Areas

.



### 10.6 Seven Factors That Must be Considered in Devel oping the LTS

40 CFR 51.308(d)(3)(v) requires “The State must con sider, at a minimum, the following factors in developing its long-term strategy:

(A) Emission reductions due to ongoing air pollutio n control programs, including measures to address reasonably attributable visibility impairme nt;201

(B) Measures to mitigate the impacts of constructio n activities;

(C) Emissions limitations and schedules for complia nce to achieve the reasonable progress goal;

(D) Source Retirement and Replacement schedules;

(E) Smoke management techniques for agriculture and forestry management purposes including plans as currently exist within the State for these purposes;

(F) Enforceability of emissions limitations and con trol measures; and

(G) The anticipated net effect on visibility due to projected changes in point, area, and mobile source emissions over the period addressed by the l ong-term strategy.”



### 10.6.1 Emission Reductions Due to Ongoing Air Poll ution Control Programs

10.6.1.1 In-Place Programs

40 CFR 51.308(d)(3)(v)(A) requires an assessment of emission reductions due to ongoing air pollution control programs. Programs that are in p lace which will assist in reducing emissions and help achieve reasonable progress toward the nat ional visibility goal include:

- Minor Source Permit to Construct Program (NDAC 33 -15-14-02) - Prevention of Significant Deterioration Program ( NDAC 33-15-15) - New Source Performance Standards (NDAC 33-15-12) - Emission Standards for Hazardous Air Pollutants ( NDAC 33-15-13)

- Emission Standards for Hazardous Air Pollutants f or Source Categories (NDAC 33-15- 22) - Oil and Gas Production Facilities Rules (NDAC 33- 15-21) - Open Burning Requirements (NDAC 33-15-04) - Fugitive Dust Control Requirements (NDAC 33-15-17 ) - Control of Sulfur Dioxide from Point Sources (NDA C 33-15-06) - Control of Particulate Matter (NDAC 33-15-05) - Control Requirements for Organic Compounds Source s (NDAC 33-15-07) - Heavy Duty Diesel Engine Standard (2007) - Tier 2 Tailpipe Standards - Large Spark Ignitor and Recreational Vehicle Rule

- Nonroad Diesel Rule

- Industrial Boiler MACT - Combustion Turbine and Reciprocating Internal Com bustion Engines NSPS and MACT

Standards

The Federal programs are described in more detail i n Section 2.5.202

Some MACT standards have been vacated; however, it is expected that revised versions of these standards will be promulgated by EPA during the pla nning period. The Department will continue to operate a PSD program and take delegati on of NSPS standards and major source MACT standards for source categories located in Nor th Dakota. As older sources are replaced, the new applicable rules should reduce emissions.

North Dakota has implemented a reasonably attributa ble visibility impact (RAVI) protection program since 1987. The rules implementing this pr ogram are found in NDAC 33-15-19, Visibility Protection. The control strategy and mo nitoring strategy are found in Chapters 3 and 6 of the State Implementation Plan. The existing RAVI program, with the existing permitting and emissions rules listed above is compatible with tho se needed for regional haze and no revisions are needed or planned at this time. The NDDoH will address the periodic review and revision requirements of the long-term RAVI strategy as requ ired by 40 CFR 51.306(c) and coordinate them with the regional haze LTS periodic progress r eports required by 40 CFR 51.308(g).



### 10.6.1.2 Coyote Station

Once reductions are achieved from the BART sources, the Coyote Station will be the largest point source of NO

x emissions in North Dakota. The analysis in Sectio n 9.5.1 indicates that additional controls on the Coyote Station are not r easonable at this time; however, the State, through recent discussions with Otter Tail Power Co mpany, has reached an agreement whereby

Otter Tail has committed to reduce NO

x emissions at the station. Otter Tail Power Compan y has indicated they will install equipment by July 1, 20 18 in order to reduce NO

x emissions to 0.50

lb/10 6 Btu. This represents a 35% decrease from the 2008 emission rate of 0.77 lb/10 6 Btu and

26% from the baseline emission rate evaluated in Se ction 9.5.1. The reductions are expected to be achieved by installing separated over fire air. This will reduce annual NO

x emissions by 4,213 tons from the 2000-2004 baseline, a 32% decre ase. The mechanism/requirement for reducing NO

x emissions is included in a Permit to Construct fou nd in Appendix A. Although

there will be NO

x reductions at this facility, it will be reevaluate d during future planning periods

to determine if additional emissions reductions are required.



### 10.6.1.3 Heskett Station Unit 2 – Reserved



### 10.6.2 Measures to Mitigate the Impacts of Constru ction Activities

40 CFR 51.308(d)(3)(v)(B) requires the consideratio n of measures to mitigate the impacts of construction activities. North Dakota regulates fu gitive emissions by rule (NDAC 33-15-17).

This rule states:

“No person shall cause or permit fugitive emissions from any source whatsoever, including a building, its appurtenances, or a road, to be used, constructed, altered, repaired, or demolished; or activities such as load ing, unloading, storing, handling, or transporting of material without taking reasonable precautions to prevent such emissions from causing air pollution as defined in section 33 -15-01-04.”203

NDAC 33-15-17-02 also states in part:

“No person shall emit or cause to be emitted into t he ambient air from any source of fugitive emissions as specified in section 33-15-17 -01 any particulate matter which:

2. Exceed the ambient air quality standards of chap ter 33-15-02 at or beyond the property line of the source.

3. Exceed the prevention of significant deteriorati on of air quality increments of chapter 33-15-15 at or beyond the property line of the source for sources subject to chapter 33-15-15.

4. Exceed the restrictions on the emission of visib le air contaminants of chapter 33-15- 03, at or beyond the property line of the source.

5. Would have an adverse impact on visibility, as defined in chapter 33-15-19, on any

class 1 federal area.”

The Department requires permits for asphalt concret e plants and rock, sand and gravel plants which are generally associated with major construct ion projects. The Department requires notification of the relocation of asphalt plants in order to track the emissions from these facilities

.

The Federal Class I areas in North Dakota are locat ed in the western part of the State, generally away from the major population centers. These popu lation centers are 40 - 500 km away from the Class I areas. Any construction in these areas should have little effect on visibility in the Class I areas because of the transport distance and prevailing winds will generally move the fugitive emissions in the opposite direction. Any impacts on visibility in a Class I area due to construction activities would most likely be associ ated with energy development including oil and gas well pad construction, compressor station c onstruction and gas processing plant construction. Owners of sources subject to permitt ing requirements, including the above energy facilities, are subjected to fugitive dust control requirements included in the permit issued for the construction of the facility. In addition, all sou rces are subject to the requirements of NDAC 33-

15-17. NDAC 33-15-17-03 lists the measures which are considered reasonable precautions for abating and preventing fugitive dust. These includ e:

1. Unpaved roads and unpaved parking areas. Abatem ent and preventive measures include but shall not be limited to frequent watering, addi tion of dust palliatives, detouring, paving, closure, speed control, or other means such as surface treatment with penetration chemicals (ligninsulfonates, oil, water, cutbacks, etc.) or methods of equal or greater effectiveness in reducing the air contaminant produ ced.

2. Demolition, wrecking and explosive detonation ac tivities; earth and construction material moving, mining, and excavation activities.204

a. Abatement and preventive fugitive particulate co ntrol measures include, but are

not limited to:

(1) Wetting down, including prewatering.

(2) Landscaping and replanting with native vegeta tion.

(3) Covering, shielding or enclosing the area.

(4) Paving, temporary or permanent.

(5) Treating, the use of dust palliatives and che mical stabilization.

(6) Detouring.

(7) Restricting the speed of vehicles on sites.

(8) Preventing the deposit of dirt and mud on imp roved streets and roads.

(9) Minimizing topsoil disturbance and reclaiming as soon as possible.

b. Sequential blasting be employed whenever or wher ever feasible to reduce the amounts of particulate matter.

c. Such dust control strategies as revegetation, de lay of topsoil disturbance until necessary, or surface compaction and sealing, be ap plied.

d. Haulage equipment be washed or wetted down, trea ted, or covered when necessary to minimize the amount of dust becoming a irborne in transit and in loading.

e. Stockpile of materials be treated to prevent blo wing or the material be contained

in silos or other suitable enclosures.

f. Waste disposal sites be so operated and construc ted as to prevent particulate matter from becoming airborne.

g. All conveyors, transfer points, crushers, screen s, and dryers be so constructed, protected, or treated as to prevent particulate mat ter from becoming airborne.

h. These measures also be used during period when a ctual construction work is not being conducted, such as on weekends and holidays.

The construction of oil well pads are normally a on e or two-day undertaking. The emissions are generally ground level emissions and do not travel very far. In general, compressor stations and gas plant construction are subject to the Permit to Construct program. These permits and rules205

will assure that construction activities will not a dversely affect visibility in any Federal Class I

area.

Emissions from construction activities including co nstruction of oil well pads, compressor stations and gas plants will be reevaluated in futu re Regional Haze SIP planning periods since this has the potential to be a growing source categ ory.



### 10.6.3 Emissions Limitations and Schedules for Com pliance

40 CFR 51.308(d)(3)(v)(C) requires the State to con sider emissions limitations and schedules for compliance to achieve the reasonable progress goal in developing its LTS.

Emissions limitations and schedules for the seven B ART sources are found in Section 7, Best Available Retrofit Technology (BART). They are inc luded in the Air Pollution Control Permit to Construct for each source. The permits found in Appendix D are incorporated as part of this

SIP.



### 10.6.4 Source Retirement and Replacement Schedules

40 CFR 51.308(d)(3)(v)(D) requires the State consid er any source retirement and replacement schedules in developing its LTS. The Department is not aware of any anticipated major source retirements or replacements. Replacement of existi ng facilities will be managed in conformance with the existing State Implementation Plan includi ng the Prevention of Significant Deterioration

program.

The 2018 modeling conducted by WRAP included three new power plants to be located in the State. It is now unlikely that two of these plants will be built. Thus the modeling results for 2018 are probably conservative. Construction of ne w power plants or replacement of existing plants prior to 2018 is unlikely.



### 10.6.5 Smoke Management Techniques for Agriculture and Forest

Management

40 CFR 51.308(d)(3)(v)(E) requires the State to con sider smoke management techniques for agriculture and forestry management purposes includ ing plans as currently exist within the State for these purposes in developing its LTS. North Dak ota has an area of approximately 68,994 square miles (44.16 million acres). Of this total, 26.5 million acres is crop land, 10.98 million acres is pasture/rangeland and 236,000 acres is woo dland/forest with the five State forests comprising 13,300 acres. The North Dakota State Im plementation Plan contains rules which govern prescribed burning on crop land, pasture/ran geland or woodland. NDAC 33-15-04-02.2 lists the conditions that apply to any prescribed b urning including:206

c. Care must be used to minimize the amount of dirt on the material being burned and the material must be dry enough to burn cleanly.

d. Oils, rubber, and other materials that produce u nreasonable amounts of air contaminants may not be burned.

e. The burning may be conducted only when meteorolo gical conditions favor smoke dispersion and air mixing.

h. Except in an emergency, burning may not be condu cted in such proximity of any class 1 area, as defined in chapter 33-15-15, that the ambient air of such area is adversely impacted.

i. Except in an emergency, the visibility of any cl ass 1 area cannot be adversely impacted as defined in chapter 33-15-19.

j. Burning activities must be attended and supervis ed at all times burning is in

progress.

Fires purposely set to woodland/forest or rangeland for the management of the land or game must be in accordance with practices recommended by State and Federal agencies and must be approved in advance by the Department (NDAC 33-15-0 4-02.1.e). Although agricultural crop burning does not require advanced approval by the D epartment, most of this burning takes place in the eastern two thirds of State away from the Cl ass I areas in North Dakota. In general, prevailing winds carry the smoke from crop land bur ning away from the North Dakota Class I areas. For 2000-2004 (Case Plan 02d), the WRAP has estimated the annual emissions from fire

in North Dakota as shown in Table 10.1.

Table 10.1

Annual Average Emissions from Fire (2000-2004)

Source PM fine (tpy) PM
coarse

(tpy) NO

x

(tpy) SO 2

(tpy) Organic

Carbon (tpy) Elemental

Carbon (tpy)
Natural 225 441 773 250 2,214 424 Anthropogenic 596 62 1001 290 1,443 86
Total 821 503 1774 540 3,657 510

Based on the source apportionment analyses conducte d by the WRAP, anthropogenic fire

emissions in North Dakota contribute less than 1% o f the total emissions of any of the pollutant species listed above during the 20% worst visibilit y days for either Lostwood Wilderness Area or

Theodore Roosevelt National Park as shown in Table 10.2. The contribution of anthropogenic fire is expected to decrease by 2018. As indicated earlier, open burning is subject to regulation under NDAC 33-15-04 which specifically prohibits bu rning that will adversely affect visibility in any Class I area. The Department has determined th at the current smoke management rules are207

sufficient to achieve reasonable progress toward th e national visibility goal. However, the smoke management rules will be reevaluated during f uture planning periods.

Table 10.2 North Dakota Anthropogenic Fire Contribution to the 20% Worst Days

Class I Area Pollutant Contribution

2000-2004 (%) Contribution

2018 (%)

TRNP SO

x NO

x POA

EC

PMF

PMC 0.013

0.019

0.364

0.067

0.04

0.001 0.004

0.006

0.112

0.024

0.013

0

LWA SO

x NO

x POA

EC

PMF

PMC 0.008

0.024

0.823

0.13

0.049

0.001 0.002

0.007

0.252

0.046

0.015

0



### 10.6.6 Enforceability of Emission Limitations and Control Measures

40 CFR 51.308(d)(3)(v)(F) requires the State must c onsider the enforceability of emission limitations and control measures in developing its LTS. The BART emission limits and control

measures will be included in a BART Air Pollution C ontrol Permit to Construct that is issued to each BART source and are incorporated into this SIP . The Permit to Construct program is

established in the State Air Pollution Control Rule s (NDAC 33-15-14-02). The program is also approved into the State Implementation Plan. The B ART permits are included in Appendix D of this SIP. Other ongoing programs are already inclu ded in the State rules. Future NSPS and MACT rules for major sources will be adopted into t he State Rules and delegation will be requested from EPA.



### 10.6.7 The Anticipated Net Effect on Visibility Du e to Projected Changes

in Point, Area and Mobile Source Emissions

40 CFR 51.308(d)(3)(v)(G) requires the State consid er the anticipated net effect on visibility due to projected changes in point, area, and mobile sou rce emissions over the period addressed by the long-term strategy in developing its LTS. The anti cipated net effect on visibility due to projected changes in emissions from 2004 to 2018 is discussed in Section 8, Visibility Modeling.208



## 10.7 Prevention of Significant Deterioration

In North Dakota, new and modified existing major st ationary sources triggering significance thresholds are analyzed under the Prevention of Sig nificant Deterioration (PSD) permitting program. The PSD program rules are found in NDAC C hapter 33-15-15 and have been approved as a part of the North Dakota SIP by EPA. The PSD permitting program is an integral part of North Dakota’s long-term strategy for meeti ng its regional haze goals.

Among other things, the PSD permit program is desig ned to protect air quality and visibility in Class I areas by requiring best available control t echnology (BACT) and involving the public in permit decisions. The PSD permitting process requi res a technical air quality analysis and additional analyses to assess the potential impacts of emissions on soils, vegetation and visibility. The cumulative impacts of emissions subject to the PSD program will be evaluated to ensure there is no degradation from baseline conditions on the 20 percent worst days and the 20 percent best days.

Therefore, North Dakota’s current PSD program ensur es that visibility at the Class I areas will not be impacted by growth in stationary sources.209



## 11. Commitment to Consultation, Progress Reports, P eriodic Evaluations of Plan Adequacy, and Future SIP Revi sions

11.1 Future Consultation Commitments

11.1.1 FLM Consultation and Coordination

40 CFR 51.308(i) contains the requirements for Stat e and Federal Land Manger consultation and coordination. §51.308(i) reads “What are the requir ements for State and Federal Land Manager

coordination?

(1) By November 29, 1999, the State must identify i n writing to the Federal Land Managers

the title of the official to which the Federal Land Manager of any mandatory Class I Federal area can submit any recommendations on the implementation of this subpart including, but not limited to:

(i) Identification of impairment of visibility in any mandatory Class I Federal area(s);

and

(ii) Identification of elements for inclusion in t he visibility monitoring strategy required by § 51.305 and this section.

(2) The State must provide the Federal Land Manage r with an opportunity for consultation, in person and at least 60 days prior to holding any public hearing on an implementation plan (or plan revision) for regional haze required by this subpart. This consultation must include the opportunity for the affected Federal La nd Managers to discuss their:

(i) Assessment of impairment of visibility in any m andatory Class I Federal area; and

(ii) Recommendations on the development of the reas onable progress goal and on the development and implementation of strategies to add ress visibility impairment.

(3) In developing any implementation plan (or plan revision), the State must include a description of how it addressed any comments provid ed by the Federal Land Managers.

(4) The plan (or plan revision) must provide proced ures for continuing consultation between the State and Federal Land Manager on the implement ation of the visibility protection program required by this subpart, including develop ment and review of implementation plan revisions and 5-year progress reports, and on the implementation of other programs having the potential to contribute to impairment of visibility in mandatory Class I Federal

areas.”210

North Dakota commits to coordinate and consult with the Federal Land Managers as required in §51.308(i)(1) through (4).



### 11.1.2 Tribal Consultation

North Dakota will continue to remain in contact wit h those Tribes which may reasonably be anticipated to cause or contribute to visibility im pairment in North Dakota mandatory Class I Federal area(s). For those Tribes that adopted a RH TIP, North Dakota will consult with them directly. For those Tribes without a RH TIP, North Dakota will consult with both the Tribe and

EPA. Documentation of the consultations will be mai ntained.



### 11.1.3 Interstate Consultation and Coordination

40 CFR 51.308(d)(1)(iv) and 40 CFR 51.308(d)(3)(i) contain the requirements for interstate consultation and coordination. §(d)(1)(iv) reads:

“In developing each reasonable progress goal, the S tate must consult with those States which may reasonably be anticipated to cause or con tribute to visibility impairment in the mandatory Class I Federal area. In any situation in which the State cannot agree with another such State or group of States that a goal p rovides for reasonable progress, the

State must describe in its submittal the actions ta ken to resolve the disagreement. In reviewing the State’s implementation plan submittal , the Administrator will take this information into account in determining whether the State’s goal for visibility improvement provides for reasonable progress toward s natural visibility conditions.” §(d)(3)(i) reads:

“Where the State has emissions that are reasonably anticipated to contribute to visibility impairment in any mandatory Class I Federal area lo cated in another State or States, the State must consult with the other State(s) in order to develop coordinated emission management strategies. The State must consult with any other State having emissions that are reasonably anticipated to contribute to visibil ity impairment in any mandatory Class I

Federal area within the State.”

In accordance with 40 CFR 51.308(d)(1)(iv) and 51.3 08(d)(3)(i), North Dakota commits to continue consultation with Minnesota, Montana, and South Dakota, and any other state which may reasonably be anticipated to cause or contribut e to visibility impairment in federal Class I

areas located within North Dakota. North Dakota wil l also continue consultation with Michigan, Minnesota, Montana, and South Dakota and any other state for which North Dakota’s emissions may reasonably be anticipated to cause or contribut e to visibility impairment in those state’s

federal Class I areas.

With reference to the established or updated goals for reasonable progress, should disagreement arise between another state or group of states, Nor th Dakota will describe the actions taken to resolve the disagreement in future RH SIP revisions for EPA’s consideration. With reference to211

assessing or updating long-term strategies, North D akota commits to coordinate its emission management strategies with affected states and will continue to include in its future RH SIP revisions all measures necessary to obtain its shar e of emissions reductions for meeting progress goals.



### 11.2 Commitment to Progress Reports

Requirements for the State to submit periodic progr ess reports are found in 40 CFR 51.308(g) which reads “Requirements for periodic reports desc ribing progress towards the reasonable progress goals. Each State identified in §51.300(b) (3) must submit a report to the Administrator every five years evaluating progress towards the re asonable progress goal for each mandatory

Class I Federal area located within the State and i n each mandatory Class I Federal area located outside the State which may be affected by emission s from within the State. The first progress report is due 5 years from the submittal of the ini tial implementation plan addressing paragraphs (d) and (e) of this section. The progress reports m ust be in the form of implementation plan revisions that comply with the procedural requireme nts of §51.102 and §51.103. Periodic progress reports must contain at a minimum the foll owing elements:

(1) A description of the status of implementation o f all measures included in the implementation plan for achieving reasonable progre ss goals for mandatory Class I

Federal areas both within and outside the State.

(2) A summary of the emissions reductions achieved throughout the State through implementation of the measures described in paragra ph (g)(1) of this section.

(3) For each mandatory Class I Federal area within the State, the State must assess the following visibility conditions and changes, with v alues for most impaired and least impaired days expressed in terms of 5-year averages of these annual values.

(i) The current visibility conditions for the most impaired and least impaired days;

(ii) The difference between current visibility cond itions for the most impaired and least impaired days and baseline visibility conditi ons;

(iii) The change in visibility impairment for the m ost impaired and least impaired days over the past 5 years;

(4) An analysis tracking the change over the past 5 years in emissions of pollutants contributing to visibility impairment from all sour ces and activities within the State. Emissions changes should be identified by type of s ource or activity. The analysis must be based on the most recent updated emissions inven tory, with estimates projected forward as necessary and appropriate, to account fo r emissions changes during the applicable 5-year period.212

(5) An assessment of any significant changes in ant hropogenic emissions within or outside the State that have occurred over the past 5 years that have limited or impeded progress in reducing pollutant emissions and improving visibili ty.

(6) An assessment of whether current implementation plan elements and strategies are sufficient to enable the State, or other States wit h mandatory Federal Class I areas affected by emissions from the State, to meet all e stablished reasonable progress goals.

(7) A review of the State’s visibility monitoring strategy and any modifications to the strategy as necessary.”

In accordance with the requirements listed in 40 CF R 51.308(g) of the federal regional haze rule, North Dakota commits to submitting periodic progres s reports to EPA every five years following the initial submittal of the SIP. The periodic prog ress reports will address at a minimum all the elements of §51.308(g). The periodic progress repor ts will be in the form of implementation plan revisions that comply with the procedural requireme nts of 40 CFR 51.102 and 51.103.



### 11.3 Determination of Current Plan Adequacy

Based on the findings of the 5-year periodic progre ss report, 40 CFR 51.308(h) requires a State to make a determination of adequacy of the existing implementation plan. §51.308(h) reads “Determination of the adequacy of existing implemen tation plan. At the same time the State is required to submit any 5-year progress report to EP A in accordance with paragraph (g) of this section, the State must also take one of the follow ing actions based upon the information presented in the progress report:

(1) If the State determines that the existing imple mentation plan requires no further

substantive revision at this time in order to achie ve established visibility goals for visibility improvement and emissions reductions, th e State must provide to the Administrator a negative declaration that further r evision of the existing implementation plan is not needed at this time.

(2) If the State determines that the implementation plan is or may be inadequate to ensure reasonable progress due to emissions from sources i n another State(s) which participated in a regional planning process, the State must prov ide notification to the Administrator and the other State(s) which participated in the re gional planning process with the States.

The State must also collaborate with the other Stat e(s) through the regional planning process for the purpose of developing additional st rategies to address the plan’s

deficiencies.

(3) Where the State determines that the implementat ion plan is or may be inadequate to ensure reasonable progress due to emissions from so urces in another country, the State shall provide notification, along with available in formation, to the Administrator.213

(4) Where the State determines that the implementat ion plan is or may be inadequate to ensure reasonable progress due to emissions from so urces within the State, the State shall revise its implementation plan to address the plan’ s deficiencies within one year.”

North Dakota commits, in accordance with 40 CFR 51. 308(h), to make a determination of the adequacy of the existing implementation plan at the same time a five-year periodic progress report is due.

Should North Dakota determine that the implementati on plan is or may be inadequate to ensure reasonable progress due to emissions from sources i n another State or States, North Dakota will provide notification to the Administrator and the o ther State(s) and collaborate with the other States(s) through the regional planning process for the purpose of developing additional strategies to address the plan’s deficiencies as re quired by §51.308(h)(2). In the event that no regional planning organizations or process exists, North Dakota will work directly with the other State(s).

Should North Dakota determine that the current impl ementation plan is or may be inadequate due to emissions from within the State itself, Nort h Dakota will develop additional strategies to address the plan deficiencies and revise the implem entation plan within one year, as required by §51.308(h)(4).

Should North Dakota determine that the implementati on plan is or may be inadequate to ensure reasonable progress due to emissions from sources i n another country, the State will provide notification, along with available information, to the Administrator as required by §51.308(h)(3).

Should North Dakota determine that the existing im plementation plan requires no further

substantive revision in order to achieve establishe d goals for visibility improvement and emissions reductions, North Dakota will provide the Administrator a negative declaration that further revision of the existing implementation pla n is not needed as required by §51.308(h)(1).

In addition, North Dakota commits to revise the imp lementation plan, including the reasonable progress goals, once RH SIPs from neighboring state s become available and are approved by EPA, or if the unexpected or unforeseen occurs. Th is would include, but not be limited to, projected future emissions reductions that do not o ccur, are distributed differently over an alternate geographic area, or are found to be incor rect or flawed. These revisions will be made within one year as required by §51.308(h)(4). Nort h Dakota also commits to accelerate this revision schedule if the present RH SIP is found to be significantly flawed and the 2018 reasonable progress goals cannot be reasonably atta ined.



### 11.4 Commitment to Future SIP Revisions

In addition to a SIP revision made for periodic pro gress reports as addressed in Section 11.2 and plan inadequacy as addressed in Section 11.3, 40 CF R 51.308(f) requires a State to revise and submit its regional haze implementation plan to EPA by July 31, 2018, and every ten years thereafter. 40 CFR 51.308(f) reads “Requirements fo r comprehensive periodic revisions of214

implementation plans for regional haze. Each State identified in §51.300(b)(3) must revise and submit its regional haze implementation plan revisi on to EPA by July 31, 2018 and every ten years thereafter. In each plan revision, the State must evaluate and reassess all of the elements required in paragraph (d) of this section, taking i nto account improvements in monitoring data collection and analysis techniques, control technol ogies, and other relevant factors. In evaluating and reassessing these elements, the State must addr ess the following:

(1) Current visibility conditions for the most impa ired and least impaired days, and actual progress made towards natural conditions during the previous implementation period. The period for calculating current visibility condi tions is the most recent five year period preceding the required date of the implementation p lan submittal for which data are available. Current visibility conditions must be ca lculated based on the annual average level of visibility impairment for the most and lea st impaired days for each of these five years. Current visibility conditions are the averag e of these annual values.

(2) The effectiveness of the long-term strategy for achieving reasonable progress goals over the prior implementation period(s); and

(3) Affirmation of, or revision to, the reasonable progress goal in accordance with the procedures set forth in paragraph (d)(1) of this se ction. If the State established a reasonable progress goal for the prior period which provided a slower rate of progress than that needed to attain natural conditions by th e year 2064, the State must evaluate and determine the reasonableness, based on the factors in paragraph (d)(1)(i)(A) of this section, of additional measures that could be adopt ed to achieve the degree of visibility improvement projected by the analysis contained in the first implementation plan described in paragraph (d)(1)(i)(B) of this section .”

In accordance with the requirements of section 51.3 08 (d) and (f) of the regional haze rule, North Dakota commits to revising and submitting its regio nal haze SIP by July 31, 2018 and every ten years thereafter addressing current visibility cond itions, effectiveness of the long-term strategy and affirming or revising the reasonable progress g oal for each mandatory Class I Federal area in

North Dakota.



### 11.5 Monitoring Strategy

North Dakota commits to review and reevaluate the a dequacy of and revise as necessary the existing RAVI monitoring strategy required by Secti on 51.305 and the existing regional haze monitoring strategy required by Section 51.308(d)(4 ) as a minimum, concurrently with the 5- year periodic progress reports and the 10-year plan revisions which start July 31, 2018 and every ten years thereafter. North Dakota will coordinate all reviews, reevaluations and revisions to both monitoring strategies with each other and will consult and coordinate any revisions with EPA and FLMs. The monitoring strategies are discuss ed further in Section 4 of this plan.215



### 11.6 Rules for Non-BART Point and Area Sources

The Department adopted rules in 1987 to implement P hase 1 of the federal visibility program which is Section 40 CFR 51.300 – 307 (NDAC Chapter 33-15-19 Visibility Protection, effective date October 1, 1987) and in 2006 to implement the BART portion of Phase 2 which is Paragraph 40 CFR 51.308(e) (NDAC Chapter 33-15-23 R egional Haze Requirements, effective date January 1, 2007). For a more detailed descrip tion of Phase 1 and Phase 2 of the federal visibility program see Section 2.

As a result of addressing the core requirements of the federal visibility program which are found in 40 CFR 51.308(d), the Department has determined it will be necessary to clarify its legal authority to address emissions which adversely impa ct visibility in the Class I areas from nonBART and area sources which may in the future be fo und to be reasonably controllable and reduced (see Section 9).

The Department commits to develop and adopt any nec essary rules to clarify its legal authority

to control and reduce emissions from non-BART and a rea sources that adversely impact Class I areas as expeditiously as possible but no later tha n December 31, 2012.216



## 12. Public Participation and Review Process

The Public Hearing Record is Appendix F. Included a re the Hearing Notice (F.1), Press Release (F.2), Affidavit of Publication (F.3), Invoice of P ublication (F.4), Registration List of Attendees (F.5), Hearing Transcript (F.6), Certification of H earing (F.7), and Response to Public Comments (F.8).



### 12.1 Summary of Comments Received during Public Com ment Period/Hearing

The written comments and oral comments received dur ing the 30 day public comment period and public hearing are included in Appendix F.6 as a pa rt of the Hearing Transcript and Response to

Comments.

Written comments were received from the U.S. Enviro nmental Protection Agency Region 8 in Denver CO; The U.S. Department of the Interior Nati onal Park Service in Denver CO; the National Parks Conservation Association in Chicago IL on behalf of the National Parks Conservation Association, the Dakota Resource Counc il, the Friends of the Boundary Waters Wilderness, the Plains Justice and the Dakotah Chap ter of the Sierra Club; Basin Electric Power Cooperative in Bismarck ND; Great River Energy in M aple Grove MN; and Bob Paine of

AECOM Environment on behalf of Basin Electric Power Cooperative, Great River Energy, and Minnkota Power Cooperative, Inc.

In addition, the Department received 31 nearly iden tical emails from various individuals. Mr. Jim Kambeitz presented oral testimony at the pu blic hearing and submitted written

comments that reiterated his oral comments.



### 12.2 Response to Public Comments

The Department’s responses to the comments received during the 30 day public comment period and public hearing are included in Appendix F.8.



### 12.3 Revisions to the State Implementation Plan

The Department made the following revisions to Regi onal Haze State Implementation Plan based on its review of the comments received during the 3 0 public comment period and public hearing:

• Page ii – An Approval Page was added.

• Section 4.2 – A discussion on the representativenes s of the IMPROVE monitor at the

South Unit of the Theodore Roosevelt National Park for the North Unit and Elkhorn

Ranch Unit was added.217

• Section 5.2 – A reference to the discussion in Sect ion 4.2 on the representativeness of the

IMPROVE monitor in the South Unit of TRNP was added

.

• Section 5.2 – A reference was added for the WRAP me thodology for determining

baseline conditions under Table 5.1.

• Section 7.3.4 - Exclusion of Montana Dakota Utiliti es Heskett Unit No. 2 was updated.

• Section 8.6.1 – Performance evaluation expanded to include results for the 98 th percentile

metric.

• Section 8.6.2.5 – Per EPA suggestion, conclusions m odified to acknowledge that BART emissions reductions from ND sources can significan tly improve visibility under some meteorological conditions.

• Table 9.4 – MDU Heskett Unit No. 2 was added.

• Table 9.9 – Table was modified to add additional in formation.

• Section 9.5.1 – Reasonable Progress Goals – Require d Controls for Point Sources – A sentence was added regarding the percent improvemen t in visibility for the control options evaluated.

• Section 9.5.4 – The section was relocated to Sectio n 10.6.1.2 and updated.

• Section 9.5.5 – The section was updated to discuss PM emissions and Q/D for oil wells.

• Section 9.7 – The section was updated to indicate t hat the Reasonable Progress Goals are based on the Department’s hybrid modeling.

• Section 10.6.1.2 – The section was added to address emissions reductions from the Coyote Station.

• Section 10.6.5 – The section was updated to indicat e the North Dakota smoke management rules will be reevaluated during future planning periods.

• Section 11.6 – The section was updated.

• Section 12 – Each item is now addressed as the 30 d ay public comment period and hearing has been completed.

• Appendix A.5 – A new appendix was added to address the WRAP methodology for determining baseline visibility conditions.

• Appendix F.9 – The section was deleted as it was no t required.

• Appendix I.2 – A new appendix was added to provide supplementary information for the four factor analysis by the WRAP states.

• Several spelling, grammatical and typographical cor rections were made throughout the

document.



### 12.4 Revisions to the BART Air Pollution Control Pe rmits to Construct

The Department made the following revisions to BART Air Pollution Control Permits to

Construct based on its review of the comments recei ved during the 30 day public comment period and public hearing:

• The definition of 30 day rolling average was modifi ed to match the NSPS Subpart Da language in all the BART permits.

• Condition II.A.2 was changed from “BART” to “Region al Haze” in the Stanton, Leland Olds and Minnkota permits.218

• The location of the CEM was added to Condition II.A .3 in the Stanton permit. The condition was also changed to specify that emission s from Unit 1 and Unit 10 must be measured separately.

• Condition II.A.1.c was revised to include a procedu re for demonstrating compliance if a startup is less than 24 hours in the Minnkota permi t.

• Condition II.A.2 was changed from “Data” to “Date” in the Coyote permit.

• Condition II.A.4.a was changed from “94%” to “95%” in the Coal Creek permit.

• Condition II.A.1.a of the Coyote permit was amended to specify that EUI 1 is the main

boiler.

• In Condition II.B.4 of the Coyote permit, Unit 1 wa s changed to EUI 1.

• In Condition II.A.5.e of the Coyote permit, “Condit ion II.5” was changed to “Condition

II.A.5.”

• In Condition II.A.5.b of the Minnkota, Coal Creek, Leland Olds and Stanton permits, “Condition II.5.a” was changed to “Condition II.A.5 .a.”