ATTACHMENT 1 MODELING PROTOCOL Modeling Protocol For the Proposed Desert Rock Generating Station Prepared for: Steag Power, LLC Houston, TX Prepared by: ENSR Corporation February 2004 CONTENTS 1.0 INTRODUCTION ..................................................................................................................... 1-1 1.1 Project Overview............................................................................................................. 1-1 1.2 Protocol Outline .............................................................................................................. 1-2 2.0 DESCRIPTION OF PROPOSED PROJECT............................................................................. 2-1 2.1 Site Description............................................................................................................... 2-1 2.2 Proposed Facility Design................................................................................................. 2-1 2.3 Proposed Project Emissions............................................................................................ 2-2 3.0 AIR QUALITY ATTAINMENT STATUS .................................................................................... 3-1 3.1 Area Compliance Status.................................................................................................. 3-1 3.2 Federal Regulations........................................................................................................ 3-1 3.2.1 National Ambient Air Quality Standards ................................................................ 3-1 3.2.2 Prevention of Significant Deterioration (PSD) Regulations ..................................... 3-3 3.3 New Mexico Air Regulations............................................................................................ 3-4 4.0 METEOROLOGY OF THE FOUR CORNERS AREA................................................................ 4-1 4.1 Review of Past Studies ................................................................................................... 4-1 4.2 Available Meteorological Data ......................................................................................... 4-1 4.3 Complexity of Local Winds .............................................................................................. 4-3 5.0 DISPERSION MODELING APPROACH: PSD CLASS II ANALYSIS ....................................... 5-1 5.1 Review of EPA Modeling Guidance ................................................................................. 5-1 5.2 Proposed Use of CALPUFF and RUC Data ..................................................................... 5-1 5.3 PSD Class II CALPUFF Modeling Domain....................................................................... 5-3 5.4 CALMET and CALPUFF Processing ............................................................................... 5-3 5.5 Good Engineering Practice Stack Height Analysis............................................................ 5-6 5.6 Building Cavity Analysis .................................................................................................. 5-8 5.7 Local Area Topography and Receptors............................................................................ 5-8 5.8 Worst-Case Load Determination...................................................................................... 5-8 5.9 Distant Class II Areas...................................................................................................... 5-9 6.0 DISPERSION MODELING APPROACH: PSD CLASS I ANALYSIS ........................................ 6-1 6.1 Selection of Dispersion Model ......................................................................................... 6-1 6.2 Use of CALPUFF and RUC Data..................................................................................... 6-1 6.3 Class I Modeling Domain ................................................................................................ 6-1 6.4 Receptors....................................................................................................................... 6-4 6.5 CALMET Processing....................................................................................................... 6-4 6.6 CALPUFF and CALPOST Processing for Significance Determination at Class I Areas ..... 6-8 6.6.1 PSD Increments................................................................................................... 6-9 6.6.2 Regional Haze ................................................................................................... 6-12 6.6.3 Acid Deposition .................................................................................................. 6-13 Protocol i February, 2004 7.0 PSD BACKGROUND AIR QUALITY........................................................................................ 7-1 7.1 Determination of Significant Impacts................................................................................ 7-1 7.2 Compliance with Ambient Air Quality Standards and PSD Increments.............................. 7-1 7.3 Regional Background Monitors........................................................................................ 7-2 7.3.1 Sulfur Dioxide (SO2)............................................................................................. 7-2 7.3.2 Particulate Matter (PM10)...................................................................................... 7-5 7.3.3 Nitrogen Dioxide (NO2)......................................................................................... 7-5 7.3.4 Carbon Monoxide (CO) ........................................................................................ 7-5 7.3.5 Ozone.................................................................................................................. 7-6 7.3.6 Pre-Construction Monitoring Waiver ..................................................................... 7-6 7.4 PSD and NAAQS Cumulative Modeling Assessment ....................................................... 7-7 8.0 ADDITIONAL IMPACT CONSIDERATIONS ............................................................................ 8-1 8.1 Growth Analysis.............................................................................................................. 8-1 8.2 Soils and Vegetation ....................................................................................................... 8-1 9.0 DOCUMENTATION OF RESULTS........................................................................................... 9-1 10.0 REFERENCES .................................................................................................................... 10-1 APPENDIX A AIR QUALITY AND METEOROLOGY OF NORTHWEST NEW MEXICO APPENDIX B CALPUFF MODELING AND EVALUATION USING RUC DERIVED MM5 DATA APPENDIX C RUC40 AND RUC20 INFORMATION FROM THE FORECAST SYSTEMS LABORATORY APPENDIX D SCREEN3 MODELING INPUT AND OUTPUT FILES APPENDIX E REGIONAL HAZE ASSESSMENT WITH CALPUFF AND FLAG: WHERE ARE WE NOW? APPENDIX F CONTRIBUTION OF SALT PARTICLES TO NATURAL BACKGROUND LIGHT EXTINCTION AT PSD CLASS I AREAS Protocol ii February, 2004 LIST OF TABLES Table 2-1 Design Emissions and Stack Parameters for Each of the Main Boilers at Various Operating Loads.......................................................................................................... 2-5 Table 2-2 Design Emissions and Stack Parameters for the Auxiliary Steam Generators .................. 2-6 Table 2-3 Design Emissions and Stack Parameters for the Emergency Diesel Generator ................ 2-7 Table 2-4 Design Emissions and Stack Parameters for the Diesel Fire Fighting Pump..................... 2-8 Table 3-1 National Ambient Air Quality Standards and Significant Impact Levels .......................... 3-2 Table 3-2 Comparison of Project Annual PTE to the PSD Thresholds........................................... 3-3 Table 3-3 Allowable PSD Increments (mg/m3) .............................................................................. 3-4 Table 3-4 New Mexico Ambient Air Quality Standards .................................................................. 3-5 Table 5-1 CALMET User-Defined Fields Not Specified in IWAQM Appendix A (Class II Modeling)... 5-6 Table 5-2 CALPUFF User-Defined Fields Not Specified in IWAQM Appendix A (Class II Modeling) .................................................................................................................... 5-7 Table 5-3 Distant Class II Area Receptors.................................................................................. 5-12 Table 6-1 CALMET User-Defined Fields Not Specified in IWAQM Appendix A (Class I Modeling).... 6-8 Table 6-2 Proposed PSD Class I Area Significant Impact Levels (µg/m3) ..................................... 6-9 Table 6-3 CALPUFF User-Defined Fields Not Specified in IWAQM Appendix B (Class I Modeling) .................................................................................................................. 6-10 Table 6-4 Hygroscopic and Non-Hygroscopic Extinction Coefficients (from FLAG, 2000) ............... 6-13 Table 7-1 Summary of Ambient Background Measurements ....................................................... 7-3 Table 7-2 PSD Monitoring Threshold Concentrations .................................................................. 7-6 Table 8-1 Screening Concentrations for Soils and Vegetation....................................................... 8-1 Protocol iii February, 2004 LIST OF FIGURES Figure 1-1 General