# Southern Ute Indian Reservation (2015) > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/tribal%3Asouthern_ute%3Ae484a71ea4393422 ## Record - **Collection:** Tribal code - **Document type:** Tribal code ## Text 2015 Southern Ute Indian Reservation Emission Inventory Southern Ute Indian Tribe Environmental Programs Division – Air Quality Program 71 Mike Frost Way Ignacio, Colorado 81137 ________________________________________________________________ Final Report for 2015 Southern Ute Indian Tribe Comprehensive Emissions Inventory for Criteria Pollutants, Hazardous Air Pollutants, and Greenhouse Gases __________________________________________________________________ Prepared by: Southern Ute Indian Tribe Environmental Programs Division Air Quality Program P.O. Box 737, MS# 84 Ignacio, Colorado 81137 (970) 563-4705 Oil and gas emission calculations prepared by Oakley Hayes, Air Quality Scientist Non-oil and gas emissions calculations prepared by Matt Wampler, Air Quality Analyst Emission Inventory Report prepared by Danny Powers, Air Quality Technical Manager May, 2017 Table of Contents Table of Figures............................................................................................................................. 3 List of Acronyms ........................................................................................................................... 9 I. Executive Summary ............................................................................................................ 11 II. Overview .............................................................................................................................. 12 1. Purpose of Inventory .................................................................................................. 12 2. Geographic Location of Southern Ute Indian Reservation ........................................ 12 3. Climate........................................................................................................................ 13 4. Geology ...................................................................................................................... 13 5. Sources........................................................................................................................ 13 III. Data Quality Objectives .................................................................................................. 14 1. Accuracy ..................................................................................................................... 14 2. Uncertainty ................................................................................................................. 15 3. Completeness .............................................................................................................. 15 4. Comparability ............................................................................................................. 15 IV. V. Point Sources .................................................................................................................... 15 1. Title V Oil and Gas Sources ....................................................................................... 15 2. Minor Point Sources ................................................................................................... 20 3. Landfill Gas ................................................................................................................ 30 4. Airports ....................................................................................................................... 33 Non-Point Sources ............................................................................................................... 35 1. Non-registered Oil and Gas Sources .......................................................................... 35 2. Fruitland Formation Outcrop Natural Gas Seeps ....................................................... 74 3. Gas Stations ................................................................................................................ 76 4. Aviation Gasoline ....................................................................................................... 78 5. Gravel Pits .................................................................................................................. 79 6. Residential Heating..................................................................................................... 80 7. Wildland Fires and Prescribed Burns ......................................................................... 84 8. Agricultural Burning................................................................................................... 87 VI. Mobile Sources ................................................................................................................. 88 1. On-Road Mobile Sources ........................................................................................... 88 2. Non-Road Mobile Sources ......................................................................................... 89 VII. Biogenic ............................................................................................................................. 90 VIII. 1 Summary ....................................................................................................................... 91 IX. Bibliography ................................................................................................................... 103 X. Appendix – Quality Assurance Review ........................................................................... 106 2 Table of Figures Figure 1 – 2015 Total Criteria Pollutant and HAP Emission on the Southern Ute Indian Reservation in Tons per Year .....................................................................................................................................................................................12 Figure 2 – 2015 Title V Oil and Gas Source Criteria Pollutant and GHG Emissions Estimations for the Southern Ute Indian Reservation in Tons per Year ............................................................................................................................16 Figure 3 – 2015 Title V Oil and Gas Source Criteria Pollutant Emissions on the Southern Ute Indian Reservation in Tons per Year ...............................................................................................................................................................17 Figure 4 – 2015 NOx Emissions at Title V Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year ..................................................................................................................................................17 Figure 5 – 2015 VOC Emissions at Title V Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year ..................................................................................................................................................18 Figure 6 – 2015 Title V Oil and Gas Source Hazardous Air Pollutant Emissions on the Southern Ute Indian Reservation in Tons per Year .......................................................................................................................................18 Figure 7 – 2015 Title V Oil and Gas Source Hazardous Air Pollutant Emissions on the Southern Ute Indian Reservation in Tons per Year .......................................................................................................................................19 Figure 8 – 2015 Hazardous Air Pollutant Emissions at Title V Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year .......................................................................................................19 Figure 9 – 2015 Greenhouse Gas Emissions at Title V Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year ...........................................................................................................................20 Figure 10 – 40 CFR Part 49 Minor New Source Review Program Emissions Thresholds in Tons per Year ..................21 Figure 11 – 2015 Criteria Pollutant and HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .............................................................................22 Figure 12 – 2015 Criteria Pollutant and HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .............................................................................23 Figure 13 – 2015 NOx Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .....................................................................................................23 Figure 14 – 2015 VOC Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .....................................................................................................24 Figure 15 – 2015 Total HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .....................................................................................................24 Figure 16 – 2015 Speciated HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year ...............................................................................................25 3 Figure 17 – 2015 Speciated HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year ...............................................................................................25 Figure 18 – 2015 GHG Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .....................................................................................................26 Figure 19 – 2015 Criteria Pollutant and HAP Emissions from Registered TMNSR Oil and Gas Source on the Southern Ute Indian Reservation in Tons per Year .....................................................................................................................27 Figure 20 – 2015 Criteria Pollutant and HAP Emissions from Registered TMNSR Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .....................................................................................................28 Figure 21 – 2015 Total NOx Emissions for Registered Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year .....................................................................28 Figure 22 – 2015 Total VOC Emissions for Registered Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year .....................................................................29 Figure 23 – 2015 Total HAP Emissions for Registered Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year .....................................................................29 Figure 24 – 2015 Total GHG Emissions for Registered Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year .....................................................................30 Figure 25 – 2015 Municipal Solid Waste Landfill Refuse in Place in Tons and Emissions on the Southern Ute Indian Reservation in Tons per Year ......................................................................................................................................33 Figure 26 – 2015 Municipal Solid Waste Landfill Refuse in Place in Tons and Emissions on the Southern Ute Indian Reservation in Tons per Year .......................................................................................................................................33 Figure 27 – 2015 Criteria Pollutant and HAP Emission from Airports on the Southern Ute Indian Reservation in Tons per Year .......................................................................................................................................................................34 Figure 28 – 2015 Criteria Pollutant and HAP Emissions from Airports on the Southern Ute Indian Reservation in Tons per Year ...............................................................................................................................................................35 Figure 29 – 2015 Emissions from Non-registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year ...............................................................................................................................................................36 Figure 30 – 2015 Criteria Pollutant and HAP Emissions from Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .....................................................................................................................37 Figure 31 – 2015 NOx Emissions for Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year ................................................................................................................................37 Figure 32 – 2015 VOC Emissions for Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year ................................................................................................................................38 Figure 33 – 2015 HAP Emissions for Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year ................................................................................................................................38 4 Figure 34 – 2015 GHG Emissions for Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year ...........................................................................................................................39 Figure 35 – Engines Reported for Non-Registered Oil and Gas Source in the 2016 by Engine Configuration and Horsepower .................................................................................................................................................................40 Figure 36 – 2015 Natural Gas-Fired Reciprocating Internal Combustion Engine Counts and Criteria Pollutant, HAP, and GHG Emissions on the Southern Ute Indian Reservation in Tons per Year .........................................................42 Figure 37 – 2015 Natural Gas-Fired Reciprocating Internal Combustion Engine Counts and Criteria Pollutant, HAP, and GHG Emissions on the Southern Ute Indian Reservation in Tons per Year ..........................................................43 Figure 38 – Oxides of Nitrogen Emissions from Natural Gas-Fired Reciprocating Internal Combustion Engines at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year ...............................43 Figure 39 – 2015 Volatile Organic Compound Emissions from Natural Gas-Fired Reciprocating Engines at NonRegistered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .......................................44 Figure 40 – 2015 Carbon Monoxide Emissions from Natural Gas-Fired Reciprocating Engines at Non-Registered Oil and Gas Sources in Tons per Year ................................................................................................................................44 Figure 41 – 2015 Turbine Count and Total Emissions of Criteria Pollutant, HAP, and GHG at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year ......................................................................46 Figure 42 – Theoretical Extended Natural Gas Analysis – Average of 34 Natural Gas Analyses from the Southern Ute Indian Reservation .......................................................................................................................................................47 Figure 43 – 2015 GRI-GLYCalc Model Input Parameters for TEG Dehydration Units at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation........................................................................................................49 Figure 44 – 2015 GRI-GLYCalc Model Emissions Output for TEG Glycol Dehydration Units on the Southern Ute Indian Reservation in Tons per Year ............................................................................................................................49 Figure 45 – 2015 HAP and VOC Emissions from 51 TEG Dehydration Units at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation ..........................................................................................................................50 Figure 46 – 2015 Liquid Storage Tanks at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Tank Contents and Capacity in Barrels ...............................................................................................52 Figure 47 – 2015 Assumed Annual Average Liquid Throughput Values for Produced Water, Oil and Condensate Tanks at Non-Registered Sources on the Southern Ute Indian Reservation ...............................................................53 Figure 48 – Produced Water Flash Gas Analysis from Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Mol Percent – September 2016 ................................................................................................55 Figure 49 – Condensate Flash Gas Analysis from Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Mol Percent – September 2016 ...........................................................................................................56 Figure 50 – Average Gas to Water and Gas to Condensate Ratios for Non-Registered Sources on the Southern Ute Indian Reservation – September 2016¹ .......................................................................................................................57 5 Figure 51 – 2015 VOC, HAP, and GHG Emission Totals on the Southern Ute Indian Reservation in Tons per from Liquid Storage Tanks by Tank Count, Content and Capacity .......................................................................................61 Figure 52 – 2015 VOC, HAP, and GHG Emission Totals on the Southern Ute Indian Reservation in Tons per from Liquid Storage Tanks by Tank Count, Content and Capacity .......................................................................................61 Figure 53 – Criteria Pollutant, HAP, and GHG Emissions from Heaters and Boilers at Non-registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year, Displayed by Unit Count and Heat Rating in MMBtu/hr....................................................................................................................................................................64 Figure 54 – Assumed Fugitive Emission Component Counts at Single and Co-Located Natural Gas Well-Sites on the Southern Ute Indian Reservation ................................................................................................................................65 Figure 55 – 2015 Emissions of VOC, HAP, and GHG from Equipment Leaks and Fugitive Emission Sources at NonRegistered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year .......................................67 Figure 56 - 2015 Volatile Organic Compound, HAP, and GHG Emissions from Natural Gas Driven Pneumatic Devices at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year ...........................69 Figure 57 – Assumed Values for Annual Natural Gas Blowdown Events Occurring at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in 2015 ...........................................................................................70 Figure 58 – 2015 Volatile Organic Compound, HAP, and GHG Emissions from Natural Gas Blowdowns at NonRegistered Oil and Gas Sources on the Reservation in Tons per Year .........................................................................71 Figure 59 – Wells Completed at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in 2015 .............................................................................................................................................................................72 Figure 60 – 2015 Assumed Values for Well Completion and Recompletion Activities at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation........................................................................................................72 Figure 61 – 2015 Volatile Organic Compound, HAP, and GHG Emissions from Well Completion and Recompletion Activities at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation .......................................73 Figure 62 – 2015 Average Equipment Counts at Single and Co-Located Well-Sites Located at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year ......................................................................73 Figure 63 – Average Equipment Counts at Non-Registered Oil and Gas Wells by Equipment Type ...........................74 Figure 64 - 2015 Emissions of Methane, CO2, and total GHG in CO2 Equivalence .....................................................75 Figure 65 – 2015 Annual Gasoline Throughput at Gasoline Stations Located on the Southern Ute Indian Reservation in Gallon per Year ........................................................................................................................................................76 Figure 66 – 2015 Volatile Organic Compound Emissions from Gasoline Dispensing Stations on the Southern Ute Indian Reservation .......................................................................................................................................................77 Figure 67 – 2015 Volatile Organic Compound and HAP Emissions from Aviation Gasoline on the Southern Ute Indian Reservation in Tons per Year ............................................................................................................................78 6 Figure 68 – Emissions of PM10 from Active Gravel Pits on the Southern Ute Reservation in 2015 ...........................80 Figure 69 – 2015 Fireplace and Wood Burning Stove Residential Heating Data for the Southern Ute Indian Reservation ..................................................................................................................................................................81 Figure 70 – 2015 Criteria Pollutant and GHG Emissions from Fireplaces and Wood Burning Stoves on Southern Ute Indian Reservation in Tons per Year ............................................................................................................................81 Figure 71 - 2015 Liquid Propane Residential Heating Data for the Southern Ute Indian Reservation ........................82 Figure 72 – 2015 Criteria Pollutant and GHG Emissions from Liquid Propane Gas Heating at Residential Sources on Southern Ute Indian Reservation in Tons per Year .....................................................................................................83 Figure 73 – 2015 Natural Gas Residential Heating Data for the Southern Ute Indian Reservation ............................84 Figure 74 – 2015 Criteria Pollutant and GHG Emissions from Natural Gas Heating at Residential Sources on Southern Ute Indian Reservation in Tons per Year .....................................................................................................84 Figure 75 – 2015 Forest Fire Occurrence on the Southern Ute Indian Reservation by Fuels Characteristic Classification System Fuel Bed Type and Acres Burned ..............................................................................................85 Figure 76 – 2015 Criteria Pollutant, NH3, and GHG Emissions from Prescribed Burns and Wildland Fires within the Exterior Boundaries of the Southern Ute Indian Reservation in Tons per Year ..........................................................86 Figure 77 – 2015 Criteria Pollutant, NH3, and HAP Emissions from Agricultural Burning on the Southern Ute Indian Reservation in Tons per Year .......................................................................................................................................87 Figure 78 – 2015 Criteria Pollutant Emissions from On-Road Mobile Sources on the Southern Ute Indian Reservation in Tons per Year .......................................................................................................................................89 Figure 79 – 2015 Criteria Pollutant Emissions from Non-Road Mobile Sources on the Southern Ute Indian Reservation in Tons per Year .......................................................................................................................................90 Figure 80 – 2015 Criteria Pollutant and HAP Emissions from Biogenic Sources on the Southern Ute Indian Reservation in Tons per Year .......................................................................................................................................91 Figure 81 – 2015 Criteria Pollutants, HAP and GHG Emissions on the Southern Ute Indian Reservation in Tons per Year ..............................................................................................................................................................................93 Figure 82 – 2015 NOx Emissions on the Southern Ute Indian Reservation by Source Category in Tons per Year .....94 Figure 83 – 2015 VOC Emissions on the Southern Ute Indian Reservation by Source Category in Tons per Year ......95 Figure 84 – 2015 Table of Emissions from Oil and Gas Sector Sources on the Southern Ute Indian Reservation in Tons per year ...............................................................................................................................................................96 Figure 85 – 2015 Chart of Emissions from Oil and Gas Sector Sources on the Southern Ute Indian Reservation in Tons per year ...............................................................................................................................................................97 7 Figure 86 – 2015 Chart of NOx Emissions from Oil and Gas Sector Sources on the Southern Ute Indian Reservation in Tons per year ...........................................................................................................................................................97 Figure 87 – 2015 Chart of CO Emissions from Oil and Gas Sector Sources on the Southern Ute Indian Reservation in Tons per year ...............................................................................................................................................................98 Figure 88 – 2015 Chart of VOC Emissions from Oil and Gas Sector Sources on the Southern Ute Indian Reservation in Tons per year ...........................................................................................................................................................98 Figure 89 – 2015 Chart of HAP Emissions from Oil and Gas Sector Sources on the Southern Ute Indian Reservation in Tons per year ...........................................................................................................................................................99 Figure 90 – 2015 Chart of GHG Emissions from Oil and Gas Sector Sources on the Southern Ute Indian Reservation in Tons per year ...........................................................................................................................................................99 Figure 91 – 2015 Natural Gas-Fired Reciprocating Internal Combustion Engine Counts and Emissions in Tons per Year on the Southern Ute Indian Reservation ...........................................................................................................100 Figure 92 – Comparison of NOx and VOC Emission Estimations for the Southern Ute Indian Reservation from the 2015 SUIT EI and the 2006 WRAP EI in Tons per year ...............................................................................................101 8 List of Acronyms AP-42 EPA Compilation of Air Pollutant Emission Factors API American Petroleum Institute AQP Air Quality Program BIA United States Bureau of Indian Affairs BSFC Brake Specific Fuel Consumption bbl Barrel (42 U.S. Gallons) CAA Clean Air Act CARMMS Colorado Air Resource Management Modeling Study CDPHE Colorado Department of Health and Environment CNG Compressed Natural Gas CO Carbon Monoxide CO2e Carbon Dioxide Equivalent COGCC Colorado Oil and Gas Conservation Commission CY Calendar Year CFR Code of Federal Regulations DRMS Colorado Division of Reclamation Mining and Safety EI Emissions Inventory EIA Environmental Impact Assessment EPA United States Environmental Protection Agency FAA Federal Aviation Administration GHG Greenhouse gas GSJB Greater San Juan Basin HAP Hazardous Air Pollutants hp Horse Power H2S Hydrogen Sulfide ICR Information Collection Request ITEP Institute for Tribal Environmental Professionals Kdf Cretaceous Fruitland Formation Kpcl Cretaceous Picture Cliffs Sandstone LFG Landfill Gas LP Liquid Petroleum LTO Landing and Take-off Cycles 9 MMscf Million Standard Cubic Feet MSW Municipal Solid Waste NEI National Emissions Inventory NMHC Non-methane Hydrocarbons NMOC Non-methane Organic Compounds NOx Oxides of Nitrogen NPS National Park Service O3 Ozone Pb Lead PM10 Particulate Matter 10 microns and smaller PM2.5 Particulate Matter 2.5 microns and smaller PSD Prevention of Significant Deterioration PTE Potential to Emit QA Quality Assurance RICE Reciprocating internal combustion engine scf Standard Cubic Feet SO2 Sulfur Dioxide SUIT Southern Ute Indian Tribe TEG Tri-ethylene Glycol TEISS Tribal Emissions Inventory Software Solutions THC Total Hydrocarbons TMNSR Tribal Minor New Source Review Program TOC Total Organic Compounds tpy Tons per Year USFS United States Forest Service VOC Volatile Organic Compounds WIAC Waste Industry Air Coalition WRAP Western Regional Air Partnership 4SLB Four stroke lean burn 4SRB Four stroke rich burn 2SLB Two stroke lean burn 10 I. Executive Summary The Southern Ute Indian Tribe (Tribe) Air Quality Program (AQP) has prepared an emissions inventory of all quantifiable point and non-point sources on the Southern Ute Indian Reservation (Reservation) for calendar year 2015 (CY2015). The emissions inventory was prepared according to the Environmental Protection Agency Class II emission inventory guidelines of using measured data when available or data and emissions factors from reputable sources when measured data were not available. Oil and natural gas production is the predominant industry on the Reservation and emissions data for these sources were collected directly from source operators through annual emission inventories, registrations, and a Clean Air Act (CAA) Section 114 information collection request issued by the Tribe in June, 2016. Data for other sources were collected from various reputable state, local, and federal data sources. As of January 2016, there were a total of 2,767 oil and gas production sources operating on the Reservation. These sources consisted of 37 sources operating under Title V operating permits, 5 sources operating under Tribal Minor New Source Review (TMNSR) permits, 156 sources registered under the TMNSR program, and 2,569 non-point sources with emissions below the TMNSR program thresholds, referred to in this emissions inventory as “non-registered sources”. Reservation emission totals for CY2015 were 19,231.8 tons per year (tpy) of oxides of Nitrogen (NOx), 15,467.1 tpy of Volatile Organic Compounds (VOC), 86.4 tpy of Sulfur Dioxide (SO2), 537.7 tpy of Particulate Matter 10 micrometers or less in diameter (PM10), 19,957.8 tpy of Carbon Monoxide (CO), 2,431.7 tpy of total Hazardous Air Pollutants (HAP), and 9,357,473 tpy of Greenhouse Gas (GHG) emissions measured in Carbon Dioxide Equivalents (CO2e). Total criteria pollutant and HAP emissions on the Reservation for 2015 are presented below in Figure 1. 11 Figure 1 – 2015 Total Criteria Pollutant and HAP Emissions on the Southern Ute Indian Reservation in Tons per Year II. Overview 1. Purpose of Inventory The purpose of this Emissions Inventory (EI) was to establish baseline emissions estimates for the 2015 calendar year for all quantifiable air emission sources located within the exterior boundaries of Reservation. The emissions data for the Reservation presented in this EI has been organized by source category and pollutant. The EI will be used for future air quality planning purposes, such as development of air quality regulations targeted at ozone precursors for maintaining attainment with the National Ambient Air Quality Standards, emissions modeling, and Title V permitting fee analysis. The primary air pollutants included in this EI are NOx, CO, PM10, VOC, HAP and GHG. 2. Geographic Location of Southern Ute Indian Reservation The Reservation is located in southwestern Colorado. The Reservation land area covers 1,066 square miles in three counties (La Plata, Archuleta, and Montezuma) and borders New Mexico to the south. The total area covered by this inventory is approximately 682,590 acres, which encompasses all land within the external boundaries of the Reservation. The Southern Ute Indian Tribe (Tribe) and/or its members own approximately 320,000 acres, while the remaining land mass is comprised of non-Indian and government land in a checkerboard fashion. The primary land use is agricultural and the predominant industry is oil and natural gas production. 12 3. Climate The Reservation remains generally semi-arid throughout the year. Located north of northern New Mexico desert land and south of the Colorado alpines, the average temperature range during the winter months is between twenty and forty degrees Fahrenheit. Freezing temperatures are common throughout the winter and during the 2015 calendar year the coldest month was December with a low of -1.0 degrees Fahrenheit and a monthly average of 26.2 degrees Fahrenheit. During the summer months the temperature typically remains in the high eighties to low nineties. The warmest month of 2015 was June with a high of 96.0 degrees Fahrenheit, and a monthly average of 67.6 degrees Fahrenheit. Snow is the dominant form of precipitation on the Reservation and total precipitation for calendar year 2015 was 18.37 inches. The driest month was March with a 0.34 inches of precipitation and the wettest month was October with 2.61 inches of precipitation.1 4. Geology The Reservation is situated in the northern portion of the San Juan Basin, a geologic structural basin underlying southwestern Colorado and northwestern New Mexico. The basin is composed of Cambrian to Holocene aged sedimentary rocks and contains one the largest coal-bed methane natural gas fields in the world within the Cretaceous aged Fruitland Formation.2 The majority of the natural gas production on the Reservation is coalbed methane from the Fruitland Formation, but conventional natural gas is also produced from Cretaceous aged sandstone reservoirs of the Pictured Cliffs Formation, Mesa Verde Group, and the Dakota Sandstone. Tight gas reservoirs of the Cretaceous aged Mancos Shale have also been drilled, however, no significant exploration and production has occurred within the Reservation as of 2015. 5. Sources The sources that were included in this emissions inventory were organized according to location and size. These point sources are as follows: A. Point Sources 1) Title V permitted oil and natural gas sources 2) TMNSR minor oil and natural gas sources, including: a. Permitted minor TMNSR sources, 1 Southern Ute Indian Tribe: Ambient Monitoring. (2015). 2015 AQS Ute 3 Humidity and Temperature Hourly Data. Retrieved from: http://www.southernute-nsn.gov/environmental-programs/air-quality/ambient-monitoring/ 2 Fasset, J. E., & Hinds, J. S. (1971). Geology and Fuel Resources of the Fruitland Formation and Kirtland Shale of the San Juan Basin, New Mexico and Colorado. Geological Survey Professional Paper 676. United States Government Printing Office. Retrieved from https://pubs.usgs.gov/pp/0676/report.pdf 13 b. Registered minor TMNSR sources, 3) Municipal solid waste landfills, and 4) Airports. B. Non-point Sources 1) Non-registered minor oil and natural gas sources, 2) Fruitland Formation Outcrop natural gas seeps, 3) Gasoline stations, 4) Aviation gasoline dispensing, 5) Gravel pits, 6) Residential heating, 7) Fire events (wildland fires and prescribed burns), and 8) Agricultural burning. C. Mobile Sources 1) On-road vehicles, and 2) Non-road equipment. D. Biogenic Sources III. Data Quality Objectives Data objectives for this inventory are as follows: 1. Accuracy       14 Data for this EI were collected according to EPA level II EI guidelines using measured data when available or data from reputable sources such as EPA, the Colorado Oil and Gas Conservation Commission (COGCC) and professional organizations when measured data were not available. Emission factors were developed using measured data or commonly accepted emissions factors and assumptions from EPA and professional organizations. All data sources, emission factors, assumptions, and emission calculation methodologies were documented. Utilize emission calculation models when available (GRI-GLYCalc 4.0, Tanks 4.09d, etc.) and inputs provided in annual emission reports or 2016 CAA Section 114 Information Collection Request (ICR). Compare results of 2015 SUIT EI with results from the CY2006 Western Regional Air Partnership (WRAP) Oil and Gas EI for the North San Juan Basin and the CY2014 WRAP EI for the Greater San Juan Basin. Quality Assurance review of emission totals, assumptions, emission factors, and calculation methodologies was conducted by a third party contractor. 2. Uncertainty     Reported emissions may be inaccurate. The number of unreported oil and gas sources is unknown and can only be estimated based on sources reported to COGCC. An accurate EI for small oil and gas sources has never been completed for the Reservation. Emissions differences between CY2015 SUIT EI with WRAP CY2006 and 2014 EIs may occur due to different preparation methodologies and assumptions. 3. Completeness     Capture 100% of point source emissions reported in the annual emission fees for CY2015. Capture 95% of non-point oil and gas sources in the 2016 CAA 114 ICR. Reported information will be used to extrapolate emissions to 100% to fill data gaps. Capture 80% of area sources (gas stations, etc.). 4. Comparability   IV. EI results will be compared with results from the CY2006 WRAP Oil and Gas EI for the North San Juan Basin and the CY2014 WRAP EI for the Greater San Juan Basin. Emission factors and assumptions will be compared with methodologies used in similar emission calculation applications. Point Sources 1. Title V Permitted Oil and Gas Sources Description of Sources Thirty-six oil and gas Title V sources operated on the Reservation during calendar year 2015. Sources include natural gas compressor stations, central delivery points, treating plants, and processing plants. Title V sources are defined as sources with the potential to emit (PTE) one-hundred tons per year (tpy) of a single criteria pollutant, twenty-five tpy of hazardous air pollutants (HAP) in aggregate, or ten tons per year of an individual HAP. The Tribe has full delegation of a Title V operating permit program under 40 CFR Part 70 and during calendar year 2015, thirty-five oil and gas sources operated under Tribally-issued Title V permits. One source, a natural gas processing plant, continued to operate under a Title V permit issued by EPA Region 8. 15 Data Collection Title V sources are required to report emissions annually and pay a per-ton emission fee for pollutants emitted. Emissions data for Title V sources were collected directly from the calendar year 2015 fee calculation worksheets submitted by each source to the Tribe and EPA Region 8. Actual emissions data were available for all thirty-six Title V oil and gas sources. Actual CO emissions were only reported for twenty-eight sources and actual GHG emissions (measured in carbon dioxide equivalents (CO2e)) were not reported for any sources. The missing CO and CO2e emissions data for these sources were obtained from PTE values reported in Title V permit applications representing operation in calendar years 2012 or 2013.3 This data collection methodology adheres to the EPA level II EI guidelines for utilizing measured data when available. Emissions Total criteria pollutant and GHG emissions estimated from Title V sources for the 2015 calendar year are displayed below in Figure 2 and Figure 3. Figure 2 – 2015 Title V Oil and Gas Source Criteria Pollutant and GHG Emissions Estimations for the Southern Ute Indian Reservation in Tons per Year¹, ² 2015 Title V Criteria Pollutant and GHG Emissions Estimations in Tons per Year Pollutant Emissions NOx CO¹ VOC PM10 SO2 CO2e² 2,598.2 2,817.3 1,155.0 68.8 52.3 2,012,320 ¹Actual CO emissions were obtained from the fee calculation worksheet, if the Title V source included the CO actual emissions. There were 28 Title V sources that included the actual CO emissions for the 2015 calendar year. CO emissions for 8 sources are PTE values obtained from Title V permit applications representing operations in calendar years 2012 or 2013. ²CO2e emissions for all Title V sources are PTE values obtained from Title V permit applications representing operation in calendar years 2012 or 2013 3 (2016). Southern Ute Indian Tribe or EPA Calendar Year 2015 Part Title V FEE Forms. 16 Figure 3 – 2015 Title V Oil and Gas Source Criteria Pollutant Emissions on the Southern Ute Indian Reservation in Tons per Year Oxides of Nitrogen emissions by equipment type at Title V sources for the 2015 calendar year are displayed below in Figure 4. Figure 4 – 2015 NOx Emissions at Title V Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year 17 Volatile organic compound emissions by equipment type at Title V sources for the 2015 calendar year are displayed below in Figure 5. Figure 5 – 2015 VOC Emissions at Title V Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year Total and speciated 2015 HAP emissions from Title V sources are displayed below in Figure 6 and Figure 7. Figure 6 – 2015 Title V Oil and Gas Source Hazardous Air Pollutant Emissions on the Southern Ute Indian Reservation in Tons per Year 2015 Title V Hazardous Air Pollutant Emissions in Tons per Year Pollutant Formaldehyde Benzene Toluene Xylene Ethylbenzene Acetaldehyde Acrolein n-Hexane Other HAP¹ Total Emissions 173.1 4.9 34.8 19.6 0.9 3.6 2.1 2.4 51.2 291.78 ¹Other HAP is a composite of non-speciated HAP emissions from CY 2015 Title V Fee calculation worksheets. 18 Figure 7 – 2015 Title V Oil and Gas Source Hazardous Air Pollutant Emissions on the Southern Ute Indian Reservation in Tons per Year Hazardous Air Pollutant emissions by equipment type at Title V sources for the 2015 calendar year are displayed below in Figure 8. Figure 8 – 2015 Hazardous Air Pollutant Emissions at Title V Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year 19 Greenhouse Gas emissions by equipment type at Title V sources for the 2015 calendar year are displayed below in Figure 9. Figure 9 – 2015 Greenhouse Gas Emissions at Title V Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year 2. Minor Point Sources The Tribal Minor New Source Review (TMNSR) permitting program is found at 40 CFR Part §49.151 through §49.164.4 The TMNSR permitting program includes new or modified source permitting, permits by rule, and a registration program. For the purposes of this inventory, two main categories of emission sources under this program were considered: a.) Permitted TMNSR oil and gas sources, and b.) Registered TMNSR Oil and Gas Sources. The emission thresholds for the TMNSR permitting program are located at 40 CFR Part §49.153. Minor sources with emissions less than the levels displayed in Figure 10 below are not required to obtain a permit or register under the program. The emission thresholds from 40 CFR Part 49.153 are displayed below in Figure 10. 4 40 CFR Part 49 - Indian Country: Air Quality Planning and Management. (2016). U.S. Government Publishing Office. Retrieved from http://www.ecfr.gov/cgi-bin/textidx?SID=bc4187dbf0b08beb092efe4251fe4493&mc=true&tpl=/ecfrbrowse/Title40/40cfr49_main_02.tpl 20 Figure 10 – 40 CFR Part 49 Minor New Source Review Program Emissions Thresholds in Tons per Year 40 CFR 49.153 Minor NSR Thresholds Regulated NSR Pollutant Carbon Monoxide (CO) Nitrogen Oxides (NOx) Sulfur Dioxide (SO2) Volatile Organic Compounds (VOC) PM10 PM2.5 Lead Fluorides Sulfuric Acid Mist Hydrogen Sulfide (H2S) Total Reduced Sulfur (including H2S) Reduced Sulfur Compounds (including H2S) Municipal Waste Combustor Emissions Municipal Solid Waste Landfill Emissions (measured as non-methane organic compounds) Minor NSR Thresholds for Attainment/Unclassifiable Areas in Tons per Year 10 10 10 5 5 3 0.1 1 2 2 2 2 10 10 A. Permitted Tribal Minor New Source Review Oil and Gas Sources Description of Sources This category reflects larger emission sources that would be subject to either the Prevention of Significant Deterioration (PSD), Title V operating permit program, or both programs absent enforceable emission limitations to reduce the source’s PTE. These types of permits are often referred to as “synthetic minor permits”. During calendar year 2015, twelve sources on the Reservation operated under TMNSR permits. Of the twelve sources in this category, eleven sources were natural gas compressor stations and one source was a natural gas processing plant. Five sources had permits to reduce emissions below Title V permitting thresholds and seven sources had permits to reduce emissions below the PSD permitting thresholds. Data Collection Only the five sources with TMNSR permitted emissions below the Title V permitting thresholds were included in this category in order to avoid double counting emissions. Emissions from the remaining seven sources, which hold Title V operating permits issued by the Tribe, were already accounted for under the Title V Oil and Gas Sources category of this inventory. 21 TMNSR sources are required to submit annual emissions inventories to EPA Region 8 for the pollutants regulated under each permit and emissions data was collected directly from the annual emissions inventories submitted for calendar year 2015.5 For pollutants not reported in the annual emissions inventories, the Southern Ute Indian Tribe Air Quality Program (AQP) requested and received PTE data from the source operators. This data collection methodology adheres to the EPA level II EI guidelines for using measured data when available. Emissions Total 2015 criteria pollutant, HAP, and GHG emissions from permitted TMNSR oil and gas sources on the Southern Ute Indian Reservation are presented below in Figure 11. Figure 11 – 2015 Criteria Pollutant and HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year¹ 2015 Criteria Pollutant and HAP Emissions for Permitted TMNSR Oil and Gas Sources in Tons per Year Pollutant Total (tons per PM SO 10 2 NOx CO VOC HAP CO2e year) Emissions 342.7 187.5 187.5 9.1 5.1 16.2 120,489 ¹ Emissions from a composite of (2016). CY 2015 EPA TMNSR Fee Forms and PTE data from source operators. 5 (2016). CY 2015 EPA TMNSR Fee Forms. 22 Total criteria pollutant and HAP emissions from permitted TMSNR oil and gas sources on the Southern Ute Indian Reservation are presented below in Figure 12. Figure 12 – 2015 Criteria Pollutant and HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year Total 2015 NOx emissions from permitted TMNSR oil and gas sources on the Reservation are displayed below in Figure 13. Figure 13 – 2015 NOx Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 23 Total 2015 VOC emissions from permitted TMNSR oil and gas sources on the Reservation are displayed below in Figure 14. Figure 14 – 2015 VOC Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year Total 2015 HAP emissions from permitted TMNSR oil and gas sources on the Reservation are displayed below in Figure 15. Figure 15 – 2015 Total HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 24 Total 2015 speciated HAP emissions from permitted TMNSR oil and gas sources on the Reservation are displayed below in Figure 16 and Figure 17. Figure 16 – 2015 Speciated HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 2015 HAP Emissions for Permitted TMNSR Oil and Gas Sources in Tons per Year Pollutant (tons per year) Formaldehyde Benzene Toluene Xylenes Ethylbenzene Acetaldehyde Acrolein nHexane Totals: 22.3 0.6 2.7 5.4 0.0 0.3 0.2 0.1 Figure 17 – 2015 Speciated HAP Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 25 Total 2015 GHG emissions from permitted TMNSR oil and gas sources on the Reservation are displayed below in Figure 18. Figure 18 – 2015 GHG Emissions for Permitted Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year B. Registered Tribal Minor New Source Review Oil and Gas Sources Description of Sources The TMNSR program required operators of true minor sources as defined in §49.152, to register each oil and gas source with EPA Region 8 by no later than March 1, 2013. Existing oil and gas sources, constructed or modified after March 1, 2013, but before October 3, 2016 were also required to register. All oil and gas sources constructed after March 1, 2013 are required to apply for a site-specific TMSNR permit or comply with the Oil and Gas Federal Implementation Plan for Indian Country at 40 CFR Part 49, Subpart C. As of January 2016, EPA Region 8 had received 156 oil and gas source registrations for the Reservation.6 The registrations included source locations, emission unit descriptions, and actual emissions calculations. All of the registered sources are natural gas production sources, primarily well-sites. Certain non-oil and gas sources, such as hot mix asphalt plants and stone quarrying, crushing and screening operations, also required registration with the EPA under the TMNSR program, but to date, no such sources have been registered. Presumably, non-oil and gas sources that did not register with the EPA 6 Southern Ute Indian Tribe. (2016). Information Collection Request. 26 may exist on the Reservation, and this issue will be addressed below in the data collection section. Data Collection For the purposes of this emission inventory section, only emissions from registered TMNSR sources were included. Sources with Title V operating permits or synthetic minor permits were not required to register under 40 CFR Part 49; therefore, there is little risk of double counting emissions from these sources. Emissions from Title V sources and synthetic minor sources were assessed separately, as discussed in Chapter IV Section 1 and 2A of this report. Due to the potential for registration information to be stale or out of date, the AQP issued a mandatory Clean Air Act Chapter 114 ICR in June 2016 to obtain updated and reconciled registration data from each facility operator. The ICR also included data for non-registered oil and gas sources. Specifically, the ICR requested reconciliation of the operational status of each previously registered source, equipment located at each source, and the actual emissions for calendar year 2015. The ICR also requested information that was exempted from TMNSR registration including emissions estimates for engines less than or equal to 50-hp and facility-wide emissions of HAP and GHG. It was also anticipated that the ICR could result in emissions reporting by sources that had never registered with the EPA. This data collection methodology adheres to the EPA level II EI guidelines for utilizing measured data when available. Emissions Total 2015 emissions of criteria pollutants, HAP, and GHG from registered TMNSR oil and gas sources on the Reservation are displayed below in Figure 19 and Figure 20. Figure 19 – 2015 Criteria Pollutant and HAP Emissions from Registered TMNSR Oil and Gas Source on the Southern Ute Indian Reservation in Tons per Year¹ 2015 Registered TMNSR Criteria Pollutant Emissions in Tons per Year Total PM10 SO2 NOx CO VOC HAP CO2e Emissions 4,835.3 3,859.1 964.2 51.7 23.9 312.5 631,331 Pollutant ¹Emissions from Southern Ute Indian Tribe. (2016). Information Collection Request 27 Figure 20 – 2015 Criteria Pollutant and HAP Emissions from Registered TMNSR Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year Total 2015 NOx emissions from registered TMNSR oil and gas sources on the Reservation by equipment type are displayed below in Figure 21. Figure 21 – 2015 Total NOx Emissions for Registered Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year 28 Total 2015 VOC emissions from registered TMNSR oil and gas sources on the Reservation by equipment type are displayed below in Figure 22. Figure 22 – 2015 Total VOC Emissions for Registered Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year Total 2015 HAP emissions from registered TMNSR oil and gas sources on the Reservation by equipment type are displayed below in Figure 23. Figure 23 – 2015 Total HAP Emissions for Registered Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year 29 Total 2015 GHG emissions from registered TMNSR oil and gas sources on the Reservation by equipment type are displayed below in Figure 24. Figure 24 – 2015 Total GHG Emissions for Registered Tribal Minor New Sources Review Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year 3. Landfill Gas The Southern Ute Indian Tribe has two Class II municipal solid waste (MSW) landfills within the Reservation boundaries. The first one is the Bondad Landfill located in Bondad, Colorado and the second one is the Archuleta County Landfill, located south of Pagosa Springs, Colorado. Both of the MSW disposal sites accept non-hazardous residential, commercial, and industrial waste. The Bondad landfill is owned and operated by Transit Waste, LLC and has been in operation since 1997. The Archuleta County landfill is owned and operated by Archuleta County and began operation in 1985. The Bondad Landfill operates under a tribally issued Title V operating permit and the Archuleta County Landfill reports annual landfill gas emissions to the Colorado Department of Public Health and Environment (CDPHE). Data Collection Emission data for the Archuleta County Landfill were provided by the Archuleta County Solid Waste Department and included a calendar year 2015 greenhouse gas report and an Air Pollution Emission Notice and Application for Construction Permit and Design Capacity Report. All reports were previously submitted by Archuleta County to the CDPHE. 30 Emissions data for the Bondad Landfill were directly obtained from the CY2015 Title V emissions fee form submitted to the Tribe. Emission Calculation Methodology Emissions for both the Archuleta County and Bondad landfills were estimated using the EPA’s MSW landfill emissions model, LandGEM version 3.02 (LandGEM).7 The LandGEM model estimates total landfill gas, non-methane organic compounds (NMOC), and hazardous air pollutants (HAP). The LandGEM model is based on a first-order decomposition rate equation for quantifying emissions from the decomposition of landfilled waste in MSW landfills. n 1  M i   kt ij QCH 4    kL0  e  10  i 1 j  0.1 Where: QCH4 = annual methane generation in the year of calculation (m3/year) i = 1 year time increment n = (year of the calculation) – (initial year of waste acceptance) j = 0.1 year time increment k = methane generation rate (year-1) Lo = potential methane generation capacity (m3/Mg) Mi = mass of waste accepted in the ith year (Mg) tij = age of the jth section of waste mass Mi accepted the ith year (decimal years, e.g., 3.2 years) LandGEM Inputs and Assumptions Complex microbial and biochemical reactions occur within the landfill’s interior after the waste has been deposited. The two primary constituents of landfill gas (LFG) are methane (CH4) and carbon dioxide (CO2). LFG also contains small amounts of non-methane organic compounds, which includes VOC, HAP, and GHG. LandGEM estimates the LFG from anaerobic decomposition of the waste with CH4 and CO2 content between 40 and 60 percent. The LandGEM defaults used for methane is 50 percent by volume (the model default value). The production of LFG is a continuous process until microbial reactions are limited by substrate or moisture. Other factors include climate, moisture conditions and types of solid waste accepted (degradable vs. inert). Parameters for climatic conditions used in the LandGEM model were a k-value of 0.02 year1 (an arid area that receives less than 25 inches of rain annually) and a Lo-value of 170 cubic 7 U.S. EPA - Landfill Gas Emissions Model. (2016). Retrieved from https://www.epa.gov/catc/clean-airtechnology-center-products#software. 31 meter per megagram. The VOC concentrations are assumed to be 39 percent of NMOC concentrations, consistent with the footnote C Table 2.4-2 of the EPA’s publication titled AP-42, Fifth Edition Compilation of Air Emission Factors (EPA AP-42).8 For the Bondad Landfill the concentrations of HAPs in the LFG were taken from the values reported in the Waste Industry Air Coalition (WIAC) report titled Comparison of Recent Landfill Gas Analyses with Historic AP-42 Values.9 For HAP compounds not listed in the WIAC report, emission factors from EPA AP-42 Table 2.4-1 and Section 2.4-4 were used. HAP emissions for the Archuleta County Landfill are from the LandGEM report using default emissions factors from EPA AP-42. The total estimated emissions of LFG were estimated using the flow rate and molecular weights. Emissions The estimated LandGEM emissions for Bondad Landfill were provided to the Tribe in a Title V emissions fee form package submitted by Transit Waste for calendar year 2015. Emissions estimates for Archuleta County Landfill were calculated by the Tribe using LandGEM and the waste acceptance rates and waste-in-place data values for 2015 taken from the 2015 GHG report previously submitted by Archuleta County to the CDPHE. The AQP used the same assumptions and climatic parameters used in the report for Bondad Landfill as these values have been previously reviewed and deemed acceptable when preparing the Title V permit for the Bondad Landfill. To avoid double counting emissions from the Bondad Landfill, emissions from Bondad Landfill were only included in the Landfill gas emission totals and not included in the Title V emission totals presented in Section I.V.1 of this report. Total refuse in place in tons and total emissions of VOC and HAP from MSP landfills on the Reservation for 2015 are displayed below in Figure 25 and Figure 26. 8 U.S. Environmental Protection Agency. (2016). AP-42: Compilation of Air Emission Factors. Retrieved from https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emission-factor 9 Waste Industry Coalition. (2001, January). Comparison of Recent Landfill Gas Analysis with Historic AP-42 Values. 32 Figure 25 – 2015 Municipal Solid Waste Landfill Refuse in Place in Tons and Emissions on the Southern Ute Indian Reservation in Tons per Year ¹ 2015 MSW Landfill Refuse in Place in Tons and Emissions in Tons per Year Bondad Landfill Archuleta County Landfill Totals Refuse in Place (tons) VOC (tons per year) HAPs (tons per year) 799,873 3.2 0.8 268,687 1.3 1.2 1,068,560.0 4.5 2.0 ¹An insignificant quantity of double counting of VOCs occurs because many reported HAPs are also considered VOCs. Figure 26 – 2015 Municipal Solid Waste Landfill Refuse in Place in Tons and Emissions on the Southern Ute Indian Reservation in Tons per Year 4. Airports There are three airports located within the Reservation, the Durango-La Plata County airport, the Animas Air Park and the Animas Air Park Helipark. Data Collection The AQP obtained data from EPA’s 2014 National Emissions Inventory database (NEI), which include total landing and take-off cycles (LTOs) and piston and turbine engine 33 emission estimates for the heliport, taxi and general aviation at the Animas Air Park.10 The LTOs were from the Federal Aviation Administration (FAA). The methodologies used by EPA to calculate airport emissions are detailed in the Eastern Research Group’s document titled Documentation for Aircraft Component of the National Emissions Inventory Methodology.11 Emissions data for the Animas Air Park and Animas Air Park Heliport were submitted to the NEI by EPA. Emissions data for the Durango-La Plata airport were reported to the NEI by the CDPHE. Assumptions Calendar year 2014 airport emissions are assumed to be similar to emissions from the airports during CY2015. Emissions Total 2015 criteria pollutant and HAP emissions from airports on the Reservation for 2015 are displayed in Figure 27 and Figure 28 below. Figure 27 –2015 Criteria Pollutant and HAP Emission from Airports on the Southern Ute Indian Reservation in Tons per Year¹ 2015 Criteria Pollutant and HAP Emission from Airports in Tons per Year Total NOx VOC SO2 PM10 Lead CO HAP Animas Air Park Heliport 0.0 0.0 0.0 0.0 0.0 0.3 0.0 Animas Air Park 0.4 0.8 0.1 1.7 0.0 30.9 0.3 Durango-La Plata County 34.5 16.6 4.2 10.5 0.1 167.2 4.8 Total 34.9 17.5 4.3 12.2 0.1 198.4 5.1 ¹Emissions estimations for airports are from the 2014 EPA National Emission Inventory Database and assumed to be realistic estimations of airport emissions for 2015. 10 U.S. EPA National Emission Inventory Emissions Inventory System. (2014). Retrieved from https://eis.epa.gov/eis-system-web/welcome.html 11 Eastern Research Group. (2001, January). Documentation for Aircraft Component of the National Emissions Inventory Methodology. (ERG No. 0245.03402.011). 34 Figure 28 – 2015 Criteria Pollutant and HAP Emissions from Airports on the Southern Ute Indian Reservation in Tons per Year ¹Emissions estimations for airports are from the 2014 EPA National Emission Inventory Database and assumed to be realistic estimations of airport emissions for 2015. V. Non-Point Sources 1. Non-registered Oil and Gas Sources Description of Sources For the purpose of this EI non-registered oil and gas sources are defined as: oil and gas sources with emissions below the thresholds that require registration under the EPA Tribal Minor New Source Review (TMNSR) Program at 40 CFR Part 49. The majority of these sources are natural gas and oil well-sites, which are comprised of artificial lift engines, separators, filter coalescers, compressor engines, reciprocating compressors, lube oil tanks, tank heaters, dehydration units, and produced water, condensate, and oil tanks. Data Collection Source information for non-registered oil and gas sources was obtained through a mandatory Clean Air Act Section 114 ICR issued by the AQP in June of 2016 to each known operator with sources operating on the Reservation. To identify the operators within the Reservation 35 and estimate the total number of non-registered sources on the Reservation, the AQP compiled site and ownership data from the COGCC and Drilling Edge databases.12,13 The ICR was the basis for collecting the information necessary to calculate emissions from non-registered oil and gas sources and required each recipient to provide actual equipment counts, production information, and equipment configuration estimations for single and colocated well-sites. Data was requested for each company’s operations on the Reservation in its entirety and not specific to any single source location. Completed ICRs were submitted by 82% of the companies that reported production on the Reservation in CY2015 to the COGCC or Drilling Edge databases. Data obtained from the ICRs accounted for the equipment and production associated with 98% of the 2,588 known non-registered oil and gas sources on the Reservation. The AQP used ground surveys to estimate equipment counts for the remaining unreported sources. Calculation Methodology The AQP calculated emissions for non-registered oil and gas sources on equipment basis using widely accepted emission factors and emission calculation methodologies, the equipment counts reported in the ICR, and CY2015 production data from the COGCC and Drilling Edge databases. Emissions totals for the 2% of non-reported sources were extrapolated to 100% based on the equipment configuration estimations derived from data obtained in the returned ICR and equipment counts taken during ground surveys. Descriptions of how emissions were calculated for each equipment type are included later in this section. Non-Registered Oil and Gas Sources Emissions Summary Criteria pollutant, HAP and GHG emission estimations from non-registered oil and gas sources on the Reservation in 2015 are displayed below in Figure 29 and Figure 30. Figure 29 – 2015 Emissions from Non-registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 2015 Emissions from Non-registered Oil and Gas Sources in Tons per Year Pollutant Emissions Totals NOx VOC SO2 PM10 CO Total HAP GHG (CO2e) 9,959.0 902.7 0.0 191.6 8,354.8 255.9 1,505,611 12 COGCC. (2015). Production Data. La Plata. Retrieved from http://cogcc.state.co.us/data2.html#/downloads 13 Drilling Edge Database (2015). Retrieved from http://www.drillingedge.com/colorado 36 Figure 30 – 2015 Criteria Pollutant and HAP Emissions from Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year Total 2015 NOx emissions from non-registered oil and gas sources on the Reservation by equipment type are displayed below in Figure 31. Figure 31 – 2015 NOx Emissions for Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year 37 Total 2015 VOC emissions from non-registered oil and gas sources on the Reservation by equipment type are displayed below in Figure 32. Figure 32 – 2015 VOC Emissions for Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year Total 2015 HAP emissions from non-registered oil and gas sources on the Reservation by equipment type are displayed below in Figure 33. Figure 33 – 2015 HAP Emissions for Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year 38 Total 2015 GHG emissions from non-registered oil and gas sources on the Reservation by equipment type are displayed below in Figure 34. Figure 34 – 2015 GHG Emissions for Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Equipment Type in Tons per Year A. Natural Gas-Fired Reciprocating Internal Combustion Engines Description of Units Natural gas-fired spark-ignited reciprocating internal combustion engines (RICE) are used by the oil and gas industry to compress natural gas, pump liquids, generate electricity, and to provide artificial lift. The most prevalent pollutants emitted from natural gas-fired RICE are NOx, CO, VOC, and HAP. Data Collection The ICR required recipients to list the total number of natural gas-fired spark-ignition and compression ignition RICE operated by their company on the Reservation. Engines were reported according to horsepower range, and engine configuration. Engine configurations included two-stroke lean-burn (2SLB), four-stroke lean-burn (4SLB), and four-stroke rich-burn (4SRB). The ICR included assumed values for engine operating hours and average brake specific fuel consumption (BSFC), and provided recipients the option to provide values more representative of their operations. A summary of reported engines is listed below in Figure 35. 39 Figure 35 – Engines Reported for Non-Registered Oil and Gas Source in the 2016 by Engine Configuration and Horsepower) Emission Calculation Methodology Criteria Pollutant and HAP Emissions: Criteria pollutant and HAP emissions were calculated for each engine configuration and horsepower rating category reported in the ICR. Emission calculations were based on the maximum horsepower of each reported horsepower range, the appropriate emission factors for stationary internal combustion sources from Chapter 3 of EPA AP-42, an assumed BSFC of 7,500 Btu/hp-hr, an assumed 100% engine operating load, and assumed operating schedule of 8,760 hours per year. The assumed BSFC value was derived by averaging the BSCF from all natural gas-fired engines in the Caterpillar Gas Engine Rating Pro software.14 All emissions were calculated for uncontrolled operation. The natural gas on the Reservation contains negligible amounts of sulfur, therefore SO2 emissions from engines are minimal. 14 Caterpillar, Inc. (2015). Gas Engine Rating Pro Emissions Estimation Software. Retrieved from http://www.cat.com/en_US/articles/solutions/oil-gas/gas_engine_rating_pro.html 40 GHG Emissions: Greenhouse gas emissions were calculated using the default values from Tables C-1 and C-2 of 40 CFR Part 98, Subpart C and the same methodology as used for criteria pollutants and HAP.15 Example Calculation Conversion of EPA AP-42 emission factor (in lb/MMBtu) to grams per horsepower hour using AQP’s assumed brake specific fuel consumption (Btu/hp-hr): g/hp-hr = (lb/MMBtu) x (7500 Btu/hp-hr) x (g/lb)/10^6 Where: EF = AP-42 emission factor (lb/MMbtu) HR = heat rating (Btu/hp-hr) Example NOx AP-42 lb/MMBtu to g/hp-hr emission factor conversion for a four-stroke rich-burn RICE: g/hp-hr = (2.21 lb/MMBtu) x (7500 Btu/hp-hr) x (456.3/ 1 lb)/10^6 = 0.752 g/hp-hr Engine emission calculation: tpy = (EF) x (hp) x (OH)/453.6 g/lb /2000 pounds/ton Where: tpy = tons per year EF = emission factor (g/hp-hr) hp = horsepower OH = annual operating hours Example NOx emissions calculation for a 200 hp four-stroke rich-burn engine operating 8,760 hours per year: tpy = (0.752 g/hp-hr) x (200 hp) x (8760 hr)/453.6 g/lb)/2000 lb/ton = 1.45 tpy NOx 15 40 CFR Part 98 - Mandatory Greenhouse Gas Reporting. (2016). U.S. Government Publishing Office. Retrieved from http://www.ecfr.gov/cgi-bin/textidx?SID=32c4baa0d0aff54fa651d1cdb1cd7934&mc=true&tpl=/ecfrbrowse/Title40/40cfr98_main_02.tpl 41 Emissions Total criteria pollutant, HAP, and GHG emissions from natural gas-fired RICE at nonregistered oil and gas sources are displayed in Figure 36 and Figure 37. Figure 36 – 2015 Natural Gas-Fired Reciprocating Internal Combustion Engine Counts and Criteria Pollutant, HAP, and GHG Emissions on the Southern Ute Indian Reservation in Tons per Year ¹ 2015 Natural Gas-Fired RICE Counts and Emissions in Tons per Year on the Southern Ute Indian Reservation¹ Engine Configuration and Horsepower (hp) 2SLB 0-50 hp 2SLB 101-200 hp 2SLB 201-300 hp 2SLB 301-400 hp 2SLB 501-600 hp 4SLB 0-50 hp 4SLB 101-200 hp 4SLB 401-500 hp 4SRB 0-50 hp 4SRB 51-100 hp 4SRB 101-200 hp 4SRB 201-300 hp 4SRB 301-400 hp 4SRB 401-500 hp Compression Ignition Total Number of Engines Reported in 2016 ICR 52 37 9 59 16 24 4 2 600 217 30 7 1 1 0 NOx CO SO2 PM10 VOC Total HAP GHG (CO2e) 206.5 760.0 281.2 2,443.4 999.7 152.9 107.2 134.0 2,160.7 1564.5 396.1 152.5 29.0 36.3 0.0 25.1 92.5 34.2 297.5 121.7 11.9 8.3 10.4 3,637.0 2,633.5 666.7 256.6 48.9 61.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 5.0 18.4 6.8 59.2 24.2 0.0 0.0 0.0 18.6 13.4 3.4 1.3 0.3 0.3 0.0 7.8 28.8 10.6 92.5 37.8 4.4 3.1 3.9 28.9 20.9 5.3 2.1 0.4 0.5 0.0 5.2 19.0 7.0 61.0 25.0 2.7 1.9 2.4 31.6 22.9 5.8 2.2 0.4 0.5 0.0 7,626.4 28,073.0 10,386.0 90,258.2 36,928.0 4,388.6 3,077.3 3,846.7 114,484.5 82,895.9 20,987.4 8,078.0 1,538.7 1,923.3 0.0 1,059 9,424 7,905.4 0.0 150.9 247.0 187.6 414,492 ¹Engine emissions are only displayed for horsepower and engine configurations reported in the 2016 ICR. 42 Figure 37 - 2015 Natural Gas-Fired Reciprocating Internal Combustion Engine Counts and Criteria Pollutant, HAP, and GHG Emissions on the Southern Ute Indian Reservation in Tons per Year Emissions of NOx, VOC, and CO from natural gas-fired RICE at non-registered oil and gas sources on the Reservation in 2015 are displayed below in Figure 38, Figure 39, and Figure 40. Figure 38 – Oxides of Nitrogen Emissions from Natural Gas-Fired Reciprocating Internal Combustion Engines at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 43 Figure 39 - 2015 Volatile Organic Compound Emissions from Natural Gas-Fired Reciprocating Engines at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year Figure 40 - 2015 Carbon Monoxide Emissions from Natural Gas-Fired Reciprocating Engines at Non-Registered Oil and Gas Sources in Tons per Year 44 B. Stationary Natural Gas Turbines: Description of Units Natural gas-fired stationary turbines are a type of rotary internal combustion engine used by the natural gas industry for natural gas transmission and for electric generation. Turbines operate by introducing compressed air and fuel into a combustion chamber to generate hot gases, which are expanded into the power turbine to rotate the power shaft and create work. Two types of combustion processes are used in turbines, the first being lean-premix staged combustion in which a lean air and fuel mixture is introduced into the combustion chamber, and the second type being diffusion flame combustion where the air and fuel mixing occurs within the combustion chamber. The power shaft is used to run a centrifugal compressor for gas transmission, or to rotate an alternator when used for electric generation. Data Collection The ICR required recipients to list the total number of natural gas-fired turbines operated by their company on the Reservation. Turbines were reported according to horsepower or kilowatt range, hours of operation, and turbine configuration. Turbine configurations included uncontrolled, water-steam injection, and lean-premix. The AQP assumed turbines to operate for 8,760 hours per year. Average brake specific fuel consumption (BSFC) was assumed to be 11,000 Btu/hp-hr, as established in the document titled Stationary Combustion Turbines in the United States.16 If an operator specific BSFC was reported in the ICR, this value was used in place of the assumed BSFC value. Only one turbine was reported at a non-registered source in the ICR. The turbine was a 0-50 hp, lean pre-mix unit, operated 8,760 hours per year, with a BSFC of 10,825 Btu/hp-hr. Emission Calculation Methodology Criteria Pollutant and HAP Emissions: Criteria pollutant and HAP emissions were calculated based on the maximum reported horsepower, emission factors for stationary gas turbines from Chapter 3.1 of EPA AP42, 100% engine operating load, an operating schedule of 8,760 hours per year and a reported BSFC of 10,825 Btu/hp-hr. The calculation methodology for natural gas turbines is the same methodology used for reciprocating internal combustion engines, and displayed in an example calculation earlier in this section. The natural gas on the Reservation contains negligible amounts of sulfur, therefore SO2 emissions from turbines are minimal. 16 McGowin (1973) Stationary Combustion Turbines in the United States. 45 GHG Emissions: Greenhouse gas emissions were calculated using the default values from Tables C-1 and C-2 of 40 CFR Part 98, Subpart C and the same methodology as used for criteria pollutants and HAP. Emissions Criteria pollutant, HAP, and GHG emissions from natural gas turbines on the Southern Ute Reservation for 2015 are displayed in Figure 41. Figure 41 - 2015 Turbine Count and Total Emissions of Criteria Pollutant, HAP, and GHG at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 2015 Turbine Count and Total Emissions in Tons per Year Turbine Configuration and Horsepower Lean-Premix 0-50 hp Number of Turbines NOx CO SO2 PM10 VOC Total HAP GHG (CO2e) 1 0.2 0.0 0.0 0.0 0.0 0.0 326.0 C. Tri-Ethylene Glycol Dehydration Units Description of Units Tri-ethylene glycol (TEG) dehydration units are commonly used in the natural gas industry to remove entrained water from the natural gas stream to meet pipeline contract water specifications. The dehydration process begins with routing the natural gas stream through TEG in an absorber (or contactor tower) where the entrained water is absorbed by the TEG. During this step, hydrocarbons present in the natural gas stream are also absorbed in the glycol. Following the absorption step, the water saturated (rich) glycol is then distilled to drive off absorbed water before being re-circulated to the absorber. The distillation step results in emissions of VOC and HAP from the reboiler still-vent. The common still-vent HAP emissions are benzene, toluene, ethyl-benzene, and xylene. Data Collection The AQP collected dehydration unit counts from the ICR, which required operators to enter the total number of dehydration units operated by their company on the Reservation during calendar year 2015. The ICR included assumed dehydration unit operating parameters and a theoretical extended natural gas analysis, as described later in this section, which could be accepted or overridden with values more representative 46 of the operators’ operations. The theoretical extended gas analysis is displayed below in Figure 42. Fifty-one dehydration units were reported in the ICR submittals and all submittals accepted the AQP’s assumed operation and natural gas composition values. Emissions Calculation Methodology Emissions for glycol dehydration units were calculated using the GRI-GLYCalc 4.0 model (GLYCalc), the AQP’s theoretical values for dehydration unit operating parameters and natural gas composition, and the methodology outlined in the GLYCalc user’s manual.17 GLYCalc is the EPA’s preferred method of quantifying emissions from glycol dehydration units for the development of tribal/state/local emissions inventories.18 Product of combustion emissions from dehydration unit reboilers were included in the emission totals for heaters and boilers presented in Section V.1. of this report to avoid double counting. Figure 42 – Theoretical Extended Natural Gas Analysis – Average of 34 Natural Gas Analyses from the Southern Ute Indian Reservation Theoretical Extended Natural Gas Analysis Component Methane Ethane Propane Isobutane n-Butane Isopentane n-Pentane n-Hexane Carbon Dioxide Nitrogen Hydrogen Sulfide Helium 2,2 Dimethylbutane 2,3 Dimethylbutane Cyclopentane 2-Methylpentane 3-Methylpentane 2,2 Dimethylpentane Methylcyclopentane 2,4-Dimethylpentane 2,2,3-Trimethylbutane Benzene Average 92.2564% 1.1672% 0.3324% 0.0548% 0.0811% 0.0200% 0.0132% 0.0089% 5.9084% 0.1370% 0.0000% 0.0000% 0.0002% 0.0007% 0.0000% 0.0018% 0.0010% 0.0000% 0.0000% 0.0000% 0.0000% 0.0007% 17 Gas Research Institute. (2000). GLYCalc Version 4.0. Retrieved from http://sales.gastechnology.org/000102.html 18 U.S. EPA. (1995). Glycol Dehydrator Emissions Test Report and Emissions Estimation Methodology. Retrieved from https:www3.epa.gov/ttn/chief/old/efdocs/glycoldehydratortestreport.pdf 47 3,3-Dimethylpentane Cyclohexane 2-Methylhexane 2,3-Dimethylpentane 1,1-Dimethylcyclopentane 3-Methylhexane 1,t-3-Dimethylcyclopentane 1,c-3-Dimethylcyclopentane 3-Ethylpentane 1,t-2-Dimethylcyclopentane 2,2,4 Trimethylpentane n-Heptane Methylcyclohexane Toluene n-Octane Ethylbenzene 2,3-Dimethylheptane m-Xylene p-Xylene o-Xylene n-Nonane n-Decane n-Undecane n-Dodecane n-Tridecane Total: 0.0000% 0.0013% 0.0000% 0.0000% 0.0000% 0.0000% 0.0000% 0.0000% 0.0000% 0.0000% 0.0002% 0.0032% 0.0017% 0.0012% 0.0018% 0.0001% 0.0000% 0.0003% 0.0002% 0.0001% 0.0006% 0.0005% 0.0001% 0.0000% 0.0000% 100.00% Total VOC: 0.53% GRI-GLYCalc Model Input Parameters The AQP developed assumed dehydration unit operational values for natural gas temperature, pressure, and flowrate by averaging operational information from dehydration units at non-registered oil and gas sources provided by two of the largest operators on the Reservation. An assumed extended natural gas analysis was prepared by averaging 34 individual extended gas analysis from natural gas production sector compressor stations that were reported to the AQP in Title V operating permit applications between 2012 and 2014. The AQP’s assumed values were input into the GLYCalc emissions model using a pipeline water content specification of seven pounds of water per MMscf of natural gas, 1.5% H2O lean glycol, and assuming uncontrolled operation with no flash tank. 48 The assumed GLYCalc input parameter values are provided below in Figure 43. Figure 43 – 2015 GRI-GLYCalc Model Input Parameters for TEG Dehydration Units at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation 2015 GRI-GLYCalc Model Input Parameters Wet Gas Temperature (°F) Wet Gas Pressure (psig) Dry Gas Flowrate/ Throughput (MMscf/day) 68.5 353.5 0.9 Lean Glycol Water Content (weight % H2O) 1.5 Glycol Pump Type Electric/ Pneumatic Pipeline Water Content Specification (lb H2O/MMscf) 7.0 GRI-GLYCalc Model Emissions Output: Fifty-one dehydration units were reported in the ICR submittals and all dehydration unit emissions were calculated using the AQP’s default GRI-GLYCalc emissions report. The GRI-GLYCalc report was applied once to each of the 51 dehydration units reported in the ICR, and then summed to derive a Reservation-wide emissions estimate for glycol dehydration units located at non-registered oil and gas sources. No operator specific GLYCalc reports or dehydration unit emission estimations were provided in the ICR submittals. Modeled GRI-GLYCalc emissions for a single TEG dehydration unit and using the AQP’s assumed model inputs are provided in Figure 44. Figure 44 – 2015 GRI-GLYCalc Model Emissions Output for TEG Glycol Dehydration Units on the Southern Ute Indian Reservation in Tons per Year 2015 GRI-GLYCalc Model Emissions Output in Tons per Year Pollutant Methane Ethane Propane Isobutane n-Butane Isopentane n-Pentane Cyclopentane n-Hexane Cyclohexane Other Hexanes Heptanes 49 Uncontrolled Emissions 0.2341 0.0226 0.0211 0.0076 0.0156 0.0057 0.0050 0.0000 0.0080 0.0048 0.0000 0.0000 Methylcyclohexane 2,2,4-Trimethylpentane Benzene Toluene Ethylbenzene Xylenes C8+ Heavies Total HC Emissions Total VOC Emissions Total HAP Emissions Total BTEX Emissions 0.0097 0.0002 0.0237 0.0796 0.0122 0.0998 0.1469 0.6966 0.4399 0.3849 0.2153 Example Calculation Example calculation for VOC emissions from ICR Reported dehydration units: VOC Emissions (tpy) = AQP Generated GRI-GLYCalc Emissions Output x Number of 2016 ICR Reported Dehydration Units Example: 22.4 tpy annual VOC emissions = 0.4399 tpy VOC x 51 reported dehydration units Emissions Volatile organic compound and HAP emissions from 51 TEG Glycol Dehydration Units at non-registered oil and gas sources on the Reservation are provided in Figure 45. Figure 45 – 2015 HAP and VOC Emissions from 51 TEG Dehydration Units at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation 2015 HAP and VOC Emissions from 51 TEG Dehydration in Tons per Year Unit Count and Number of VOC HAP CO2e Pollutants Dehydration Units 51 22.4 11.4 70,493.4 Totals D. Liquid Storage Tanks Description of Equipment and Emissions Categories The oil and gas industry utilizes liquid storage tanks for the storage of produced water, condensate, oil, coolants, and lubricants. The primary emissions from liquid storage tanks are methane, VOC and HAPs. Emission categories include breathing and working losses, flash emissions, and tank loadout. 50 Breathing and Working Losses: Breathing losses occur when vapor expansion generated during temperature fluctuations increases the vapor pressure within a tank and cause fugitive emissions to escape from the roof vent. Light colored tanks and tank heaters can help maintain more consistent tank temperatures and reduce breathing losses by reducing vapor pressure variations. Full tanks also produce lower breathing losses due to less space for vapors to expand and escape from roof vents. Working losses occur when liquids are pumped into and out of storage tanks. The displacement of vapors within the tank and the turbulence caused by the movement of the liquid create airborne vapors. Submerged fill tanks can be effective for reducing turbulence and the creation of airborne vapors. Flash Emissions: Flash emissions are emissions that occur when liquid dumped from the separator into the liquid storage tank goes from higher pressure to lower pressure, resulting in the entrained gas being released as a vapor from the liquid. The gas to liquid ratio, pressure and temperature of the liquids in the separator and the temperature and pressure of the liquid storage tank influence the amount of flashing losses. Tank Loadout Emissions: Tank loadout emissions are vapor loss from transport tanks that occur during the transfer of liquids from a storage tank to a transport tank. Loadout emissions occur due to the generation of vapors in transport tanks during liquid loading, the transfer of vapors from the liquid storage tank to the transport tank, and the displacement of vapors trapped in transport tanks from previous loads during loading. Data Collection Tank Counts and Data for Calculating Breathing and Working Losses: The ICR required each operator to provide the total number of produced water, condensate, and oil tanks located at their non-registered sources on the Reservation. Reported tank counts were based on tank contents and capacity in barrels (bbl). A summary of tanks reported in the ICR, by tank capacity and contents, is displayed below in Figure 46. 51 Figure 46 – 2015 Liquid Storage Tanks at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation by Tank Contents and Capacity in Barrels The ICR also provided operators with the opportunity to override assumed data values for annual liquid throughput, Reid Vapor Pressure, and general tank characteristics with values more representative of their operations. Tank characteristics include roof type, color, condition, and presence of a tank heater. Development of liquid throughput values is discussed later in this section. Emissions from lubricant oil and glycol storage tanks were assumed to be negligible and no data was requested for these sources. Methodology for Deriving Average Liquid Throughput Values: The AQP developed two types of annual liquid throughput values, based on the availability of data in the COGCC database for sources in La Plata County, Colorado for CY2015. If data were available from COGCC, the AQP developed specific operator throughput values and if the data was not available, the AQP developed assumed annual average liquid throughput values. The operator specific annual average liquid throughput values were derived by dividing their total reported produced water and condensate/oil production numbers by the total number of sources that reported production for CY2015. Assumed average annual liquid throughput values were developed for operators that reported active sources to the COGCC in 2015, but did not report production. The assumed annual throughput value for produced water was derived by dividing the total CY2015 produced water production values reported to the COGCC database by the total number of reported sources. A combined condensate and oil assumed annual average tank throughput value was derived by dividing the total CY2015 combined condensate and oil production value reported to the COGCC database by the number of non52 registered sources that reported condensate or oil production. Not all companies reported condensate or oil production to COGCC and two companies reported much larger condensate and oil production numbers than other companies producing condensate and oil. Companies that did not produce any condensate or oil and the few companies with large production numbers were dropped from the calculations to avoid skewed production numbers. Assumed annual average liquid throughput values for the produced water, oil and condensate at non-registered oil and gas sources on the Reservation are displayed below in Figure 47. Figure 47 – 2015 Assumed Annual Average Liquid Throughput Values for Produced Water, Oil and Condensate Tanks at Non-Registered Sources on the Southern Ute Indian Reservation¹ 2015 Assumed Annual Average Liquid Storage Tank Throughput Values Number of Sources Operating in 2015 3,477 2015 Oil/Condensate Produced (bbl) 2015 Water Produced (bbl) 13,662 18,956,811 Average Oil/Condensate per source per year (bbl) 29.97 Average Water per source per year (bbl) 10,935 ¹Throughput numbers were derived from averaging production numbers from COGCC, (2015). Production Data. Retrieved from http://cogcc.state.co.us/data2.html#/downloads Emission Calculation Methodology Liquid storage tank emissions are calculated based on three separate emission event categories that occur during the course of normal tank operation at atmospheric pressures, as described earlier in this section. The emissions categories include: standing and working losses, flash emissions, and loadout emissions. Discussions are provided below of the methodologies used to calculate emissions for each tank emissions category. Standing and Working Losses Data Collection and Assumptions: Emission totals for the Reservation were developed for each individual operator by running the EPA TANKS 4.09d Emissions Estimation Software (TANKS) model once for each tank size and production type category reported in the ICR and then multiplying each modeled emissions total by the number of corresponding tanks reported.19 Reported liquid throughput values were used when provided and assumed throughput values were used when data was not provided. 19 U.S. EPA. (2006). TANKS 4.09d Emissions Estimation Software. Retrieved from https://www3.epa.gov/ttnchie1/software/tanks 53 Emission Calculations: Standing, and working losses were calculated using the TANKS model and reported or assumed input data values for liquid throughput, Reid vapor pressure, and tank characteristics. A produced water tank was assumed to consist of a mixture of 99% water and 1% condensate and the TANKS model default values were used for condensate and oil. The model was ran for tanks operating at atmospheric pressure and the TANKS model meteorological conditions for Albuquerque, New Mexico. Emission estimates using this geographic location may be biased slightly higher, as temperatures in Albuquerque are warmer in summer and less cold in winter than within the Reservation. All tanks were assumed to have a cone shaped roof, to be gray in color, and equipped with a tank heater. Liquid Storage Tanks Flash Emissions Data Collection and Assumptions: The ICR requested flash gas liberation data from produced water, condensate, and oil, to aid in calculating flash emissions. No ICR submittals were returned with flash liberation data, as this type of sampling is not common practice on the Reservation. In September 2016, the AQP contracted a third party vendor to perform flash liberation sampling at well-site locations operated by two different companies on the Reservation. Sampling was performed on the separator at each well-site in order to obtain a pressurized sample. In total, seven produced water samples were obtained from coal-bed methane wells of the Fruitland Coal Formation on the east and west sides of the Reservation. Two produced water samples and one condensate sample were obtained from conventional natural gas wells of the Picture Cliffs Sandstone Formation in the south central portion of the Reservation.20 Due to the very low oil production numbers reported to the COGCC database for La Plata County Colorado in CY2015 and the absence of viable sampling locations, the AQP elected to not obtain oil flash gas samples, but to use the condensate flash sampling results to estimate oil flash emissions Two additional condensate flash samples were provided by an operator that performed sampling in August 2016 from liquid knockout locations on a well-site gathering pipeline containing natural gas from conventional wells in the southern portion of the Reservation. All sampling reports included an extended gas analysis, gas to water ratio, gas specific gravity, separator temperature and pressure, and ambient temperature and pressure. Results from the six valid produced water samples were averaged to obtain assumed gas composition and gas to water ratio values to be used in the Oil to Gas Ratio calculation 20 Air Pollution Testing, Inc. (2016). Southern Ute Indian Tribe Flash Liberation Analyses. 54 for estimating storage tank flash emissions. The same methodology was applied for deriving average composition values from the three valid condensate samples. Averaged extended gas analysis values for produced water and condensate are displayed below in Figure 48 and Figure 49, respectively. Averaged gas to water and gas to condensate values are displayed below in Figure 50. Figure 48 –Produced Water Flash Gas Analysis from Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Mol Percent – September 2016¹ Produced Water Flash Gas Analysis from the Southern Ute Indian Reservation in Mol % Flash Gas Component Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Average Mol % Hydrogen Sulfide Nitrogen Carbon Dioxide Methane 0.0000 0.0373 72.3236 26.6076 0.0000 0.0000 68.4996 31.0289 0.0000 1.0883 36.5680 62.2021 0.0000 1.0464 29.7757 67.0612 0.0000 2.6862 5.8668 91.4075 0.0000 0.5921 16.3515 76.3697 0.0000 0.9084 38.2309 59.1128 Ethane 0.3200 0.0271 0.1155 0.0138 0.0119 4.0640 0.7587 Propane 0.0359 0.0231 0.0124 0.037 0.0079 1.0078 0.1874 Isobutane N-Butane 2,2 Dimethylpropane Isopentane N-Pentane 2,2 Dimethylbutane Cyclopentane 2,3 Dimethylbutane 2 Methylpentane 3 Methylpentane N-Hexane Methylcyclopentane 0.0036 0.0100 0.0035 0.0160 0.0012 0.0015 0.0049 0.0163 0.0007 0.0029 0.1582 0.1689 0.0287 0.0359 0.0000 0.0028 0.0039 0.0000 0.0000 0.0000 0.0000 0.0000 0.4360 0.0000 0.0000 0.0037 0.0078 0.0000 0.0000 0.0000 0.0000 0.0000 0.1881 0.0000 0.0000 0.0003 0.0005 0.0000 0.0000 0.0000 0.0000 0.0000 0.0005 0.0000 0.0000 0.0071 0.0117 0.0000 0.0000 0.0000 0.0000 0.0000 1.8678 0.0000 0.0000 0.0005 0.0012 0.0000 0.0000 0.0000 0.0000 0.0000 0.0035 0.0000 0.0000 0.1027 0.0612 0.0000 0.0108 0.0000 0.0000 0.0000 0.2114 0.0000 0.0000 0.0195 0.0144 0.0000 0.0018 0.0000 0.0000 0.0000 0.4512 0.0000 0.0085 0.0084 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0227 0.0418 0.0000 0.0000 0.0000 0.0021 0.0000 0.0000 0.1056 0.0481 0.0000 0.0000 0.0228 0.0167 0.0000 0.0000 0.0000 0.0000 0.0000 0.0037 0.0108 0.1872 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0006 0.0000 0.0000 0.0091 0.0000 0.0000 0.0000 0.0000 0.0081 0.0514 0.0196 0.0000 0.0003 0.0000 0.0026 0.0029 0.0016 0.0011 0.0000 0.0088 0.0000 0.2092 0.0865 0.1397 0.2745 0.0000 0.0015 0.0000 0.0354 0.0169 0.0339 0.0819 0.0000 Benzene Cyclohexane 2-Methylhexane 3-Methylhexane 2,2,4 Trimethylpentane Other C7's N-Heptane Methylcyclohexane Toluene Other C'8s N-Octane 55 Ethylbenzene M&P Xylenes O-Xylene Other C9's N-Nonane Other C10's N-Decane 0.0000 0.0008 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0141 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0049 0.0242 0.0000 0.0000 0.0000 0.0000 0.0000 0.0008 0.0065 0.0000 0.0000 0.0000 0.0000 0.0000 Undecanes(11) 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Totals: 100% 100% 100% 100% 100% 100% 100% Total VOC: 0.7116% 0.2422% 0.0261% 2.1029% 0.0273% 2.6225% 0.9554% Total HAP: 0.4561% 0.1881% 0.0005% 1.9560% 0.0054% 0.4946% 0.5168% ¹Air Pollution Testing, Inc. (2016, September). Southern Ute Indian Reservation Flash Liberation Analyses. Figure 49 –Condensate Flash Gas Analysis from Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Mol Percent – September 2016¹ Condensate Flash Gas Analysis from the Southern Ute Indian Reservation 56 Flash Gas Component Sample 1 Mol% Sample 2 Mol% Sample 3 Mol% Average Mol % Hydrogen Sulfide Nitrogen Carbon Dioxide Methane Ethane Propane Isobutane N-Butane 2,2 Dimethylpropane Isopentane N-Pentane 2,2 Dimethylbutane Cyclopentane 2,3 Dimethylbutane 2 Methylpentane 3 Methylpentane N-Hexane Methylcyclopentane Benzene Cyclohexane 2-Methylhexane 3-Methylhexane 2,2,4 Trimethylpentane Other C7's N-Heptane Methylcyclohexane 0.000 6.633 3.053 62.466 14.918 6.279 1.371 1.738 0.000 0.794 0.551 0.000 0.000 0.000 0.000 0.000 0.869 0.000 0.105 0.000 0.000 0.000 0.003 0.000 0.557 0.000 0.000 5.170 2.564 62.678 16.162 7.028 1.353 1.840 0.000 0.769 0.560 0.000 0.000 0.000 0.000 0.000 0.748 0.000 0.076 0.000 0.000 0.000 0.003 0.000 0.461 0.000 0.0000 0.5871 2.8208 50.2222 20.4293 12.0540 3.2488 3.6206 0.0000 1.7594 1.0198 0.0000 0.1844 0.0000 0.0000 0.0000 1.4232 0.0000 0.1128 0.0000 0.0000 0.0000 0.0291 0.0000 0.7371 0.2793 0.000 4.130 2.813 58.455 17.170 8.454 1.991 2.400 0.000 1.107 0.710 0.000 0.061 0.000 0.000 0.000 1.013 0.000 0.098 0.000 0.000 0.000 0.012 0.000 0.585 0.093 Toluene 0.166 0.126 0.1768 0.156 Other C'8s 0.000 0.000 0.8700 0.290 N-Octane 0.304 0.247 0.0000 0.184 Ethylbenzene 0.008 0.007 0.0076 0.008 M&P Xylenes 0.071 0.074 0.1086 0.085 O-Xylene 0.000 0.000 0.0000 0.000 Other C9's 0.000 0.000 0.0000 0.000 N-Nonane 0.088 0.088 0.0000 0.059 Other C10's 0.000 0.000 0.0000 0.000 N-Decane 0.027 0.048 0.0000 0.025 Undecanes(11) 0.000 0.000 0.0000 0.000 Totals: 100% 100% 100% 100% Total VOC: 12.9310% 13.4280% 25.6315% 17.3302% Total HAP: 1.2220% 1.0340% 1.8581% 1.3714% ¹Air Pollution Testing, Inc. (2016, September). Southern Ute Indian Reservation Flash Liberation Analyses. Figure 50 – Average Gas to Water and Gas to Condensate Ratios for NonRegistered Sources on the Southern Ute Indian Reservation – September 2016¹ Average Gas/Water and Gas/Condensate Ratios for the Southern Ute Reservation – September 2016 Gas/Water Gas/Condensate (scf/bbl) (scf/bbl) 1.8 10.1 6.1 9.1 1.4 30.3 3.7 -- -5.9 -- -1 -- -3.3 16.5 ¹Air Pollution Testing, Inc. (2016, September). Southern Ute Indian Reservation Flash Liberation Analyses. Flash Emission Calculation Methodology: Flash emissions from produced water, condensate, and oil tanks were calculated using the Gas Oil Ratio Sampling calculation methodology, and the average gas composition and gas to water and gas to condensate values developed by the AQP from flash liberation sampling data obtained in 2016 from well-sites on the Reservation. Tank throughput values in barrel per day were either reported values or the assumed values developed by AQP, as described previously in this section. Flash emission totals for the Reservation were developed for each individual operator using either reported or assumed liquid throughput values and multiplying emissions by number of corresponding tanks reported. 57 Example Gas Oil Ratio Calculation for Flash Emissions: HC Emissions = ((Q)(Rs) x (MWtv) x (lb-mol/379.4 scf) x (365 days/year) x (ton/2000 lb)) Where: Q = oil, condensate, or water production, bbl/day Rs = measured gas-oil, gas-condensate or gas-water ratio, scf/bbl MWtv = stock tank gas Molcular weight, lb/lb-mol Liquid Storage Tank Loadout Emissions Data Collection and Assumptions: Tank loadout emissions were calculated by conservatively assuming that all liquid storage tanks are unloaded manually by truck, and not sent through pipeline. Emission factors and emission calculations were derived from Section 5.2 of EPA AP-42 for Transportation and Marketing of Petroleum Liquids. Loading was assumed to be submerged fill and the saturation emission factor for submerged dedicated normal service was selected for calculating loading losses. Truck tank capacity was assumed to be 100 bbl per loadout event and reported or assumed liquid production numbers were used for calculating the number or loadout events per year. Each loadout event was assumed to be one-hour in duration and the assumed annual hours of unloading operations for each operator were directly correlated to the reported or assumed annual liquid production. Molecular weight and true vapor pressure values were derived from TANKS model runs for produced water and condensate. Example Tank Loadout Emissions Calculation Methodology: Tank loadout emissions are calculated using two separate calculations, a first equation is used to estimate the total molecular weight of loading emissions losses and then a second equation is used to estimate the total emission rate on a pollutant basis. Both calculations are displayed below: Loading Losses Calculation: L = 12.46 x (S) x (P) x ((MW)/T) x (1-eff) Where: L=Loading Losses (lb/1000 gallons) S = Saturation Factor P = True Vapor Pressure (Pva @ T) MW = Molecular Weight (lb/lb-mol) T = Temperature 58 E = Control Efficiency of Loading Total Emission Rate Calculation Tons Per Year = (TE x WT%) x (OH)/2000 Where: TE = Total Emission Rate (lb/hr) WT% = Component Weight Percentage from Flash Gas Analysis OH = Annual hour of operation Liquid Storage Tank Greenhouse Gas Emissions Produced Water Tank Greenhouse Gas Emissions: Greenhouse gas (GHG) emissions for produced water storage tanks were calculated using the emission factors and methodology from the American Petroleum Institute document titled Compendium of Greenhouse Gas Emissions for the Oil and Gas Industry.21 API emission factors are based on inlet separator pressures and an assumed inlet pressure of 71.67 psi was developed for this emission inventory by averaging pressures measured during the AQP’s 2016 flash gas sampling conducted on the Reservation. Example Calculation for Produced Water Tank GHG Emission CH4 = (PR) x (O) x (EF) Where: CH4 = annual CH4 emissions (ton/yr) PR = production rate (bbl/day) O = operation (days/yr) EF = emission factor (ton/1000 bbl) Condensate and Oil GHG Emissions: GHG emissions from condensate and oil tanks were calculated using the methodology for atmospheric pressure fixed roof storage tanks receiving hydrocarbon produced liquids from onshore petroleum and natural gas production outlined in §98.233(j) of 40 CFR Part 98 Subpart W (Subpart W). Annual volumetric GHG emissions were calculated using the emission factors and equations W-15 from §98.233(j)(3) of Subpart 21 American Petroleum Institute. (2009). Compendium of Greenhouse Gas Emissions Methodologies for the Oil and Gas Industry. Retrieved from htp://www.api.org/~media/files/ehs/climatechange/2009_ghg_compendium.ashx. 59 W. Volumetric GHG emissions were converted to mass emissions using equation W-36 from §98.233(u)(2)(v) of Subpart W. Example Condensate and Oil GHG Calculations: Annual Volumetric GHG Emissions - Equation W-15 of 40 CFR 63, Subpart W Es,i = EFi x Count x 1000 Where: Es,i = Annual total volumetric GHG emissions (either CO2 or CH4) at standard conditions in cubic feet EFi = Population emission factor for separators, wells, or non-separator equipment in thousand standard cubic feet per separator, well, or non-separator equipment per year, for crude oil use 4.2 for CH4 and 2.8 for CO2 at 60 °F and 14.7 psia, and for gas condensate use 17.6 for CH4 and 2.8 for CO2 at 60 °F and 14.7 psia. Count = Total number of separators, wells, or non-separator equipment with annual average daily throughput less than 10 barrels per day. Count only separators, wells, or non-separator equipment that feed oil directly to the storage tank. 1,000 = Conversion from thousand standard cubic feet to standard cubic feet. Annual Mass Based GHG Emissions – Equation W-36 of 40 CFR 63, Subpart W: Mass,i = (Es,i) x (pi) Where: Mass,i = GHG mass emissions kg/yr Es,i = GHG volumetric emissions in scf pi = Density of GHG Calculation to convert kg/yr from kg/yr to tons/yr tpy = (Mass,I x 2.20462)/2000 Total Liquid Storage Tank Emissions Total liquid storage tank emissions from working and breathing losses, flash emissions, tank loadout, and GHG emissions on the Reservation are displayed in below in Figure 51 and Figure 52. Emissions are displayed by tank contents and capacity. 60 Figure 51 – 2015 VOC, HAP, and GHG Emission Totals on the Southern Ute Indian Reservation in Tons per from Liquid Storage Tanks by Tank Count, Content and Capacity 2015 Liquid Storage Tank Counts and Emission Totals on the Southern Ute Indian Reservation in Tons per Year Tank Contents and Capacity Produced Water 0-210 bbl Produced Water 221-300 bbl Produced Water 301-400 bbl Produced Water 401+ bbl Condensate 0-210 bbl Condensate 211-300 bbl Oil 0-210 bbl Oil 221-300 bbl Oil 301-400 bbl Oil 400+ bbl Tank Count 412 337 209 245 63 42 22 47 5 3 VOC 3.4 37.0 10.3 12.3 49.3 52.7 9.0 28.1 2.6 2.9 HAP 0.8 15.7 3.0 3.4 0.0 0.0 0.1 0.2 0.0 0.0 GHG (CO2e) 16.8 328.7 61.8 71.5 596.9 397.9 52.5 112.1 11.9 7.2 Total Tank Count and Total Emissions 1,385 207.7 23.2 1,657.3 Figure 52 - 2015 VOC, HAP, and GHG Emission Totals on the Southern Ute Indian Reservation in Tons per from Liquid Storage Tanks by Tank Count, Content and Capacity 61 E. External Combustion Sources Description of Sources Natural gas-fired external combustion sources are widely used by the natural gas industry as tank heaters, heated separators, reboilers, and boilers. Data Collection The ICR required each operator to report the total number of heaters and boilers operated by their company on the Reservation. Heater and boiler counts were reported according to heat rate range in MMBTU/hr. Operators were also given the option to report average heater and boiler operating hours to override the AQP’s assumed operating hours. A description the AQP’s assumed values is included in the emission calculation discussion. Assumptions If no hours of operation were reported in the ICR, AQP assumed heaters to operate 24 hours per day for half of the year (183 days per year) which equates to 4,392 hours per year. Boilers were assumed to operate for 24 hours per day, 365 days a year, which equates to 8,760 hours per year. Emission Calculation Methodology Criteria pollutant and HAP emissions for external combustion sources were calculated using the emission factors from EPA AP-42 Chapter 1.4 for uncontrolled natural gasfired external combustion sources, the maximum heat rating from each heat rating category reported in the ICR, a default natural gas heating value of 1,020 Btu/scf, and assumed or reported operating hours. As explained in EPA AP-42 Chapter 1.4, a default natural gas heating value of 1,020 Btu/scf shall be used to convert the emission factor from lbs/MMscf to lbs/MMBtu. GHG emissions were calculated using the Tier 1 calculation methodology, the natural gas emission factors from Tables C-1 and C-2 of 40 CFR Part 98, and assumed or reported operating hours. Example Calculations Criteria and HAP Example Calculations: lb/hr = (EF/HV) x (HR) 62 Where: EF = Emission Factor (lb/MMscf) HV = Default Heat Value of Natural Gas fuel (Btu/scf) HR = Heat Rate of Boiler (MMBtu/hr) Example NOx lb/hr calculation for 0.5 MMBtu/hr natural gas-fired boiler: lb/hr = (0.06/1,020) x 0.5 = 2.94 E-5 tpy = (lb/hr) x OH/2000 Where: (lb/hr) = Emission Rate OH = Annual Operating Hours 2000 = Pounds per ton Example NOx tpy calculation for 0.5 MMBtu/hr natural gas-fired boiler operating 4392 hours per year: tpy = (2.94E-5) x (4392/2000)= 6.46E-5 GHG Example Calculation: Tier 1 Calculation Methodology: = (1 x 10-3) x (Fuel) x (EF) Where: Fuel = volume of fuel combusted per year (MMbtu/yr) EF = fuel specific default emission factor, from tables C-1 and C-2 of Part 98 (kg/MMBtu) 1 x 10-3 = conversion factor from kilograms to metric tons Emissions Criteria pollutant, HAP and GHG emissions from external combustion sources located at non-registered oil and gas sources on the Reservation for calendar year 2015 are displayed below in Figure 53. Emissions are displayed by unit count and heat rating in MMBtu/hr. 63 Figure 53 - Criteria Pollutant, HAP, and GHG Emissions from Heaters and Boilers at Non-registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year, Displayed by Unit Count and Heat Rating in MMBtu/hr 2015 Emissions from Heaters and Boilers at Non-registered Oil and Gas Sources in Tons per Year, Displayed by Unit Count and Heat Rating in MMBtu/hr Equipment Type and Heat Rating Heaters 0-3 MMBtu/hr Boilers 11-25 MMBtu/hr Total Unit Count NOx VOC SO2 PM10 CO HAP CO2e 742 470.4 25.9 0.0 35.5 395.1 8.9 561,830 6 748 64.4 534.8 3.5 29.4 0.0 0.0 4.9 40.4 54.1 449.2 1.2 10.1 76,933 638,763 F. Equipment Leaks and Fugitive Emissions Description of Sources Natural gas leaks from components commonly used in the natural gas industry result in emissions of methane, CO2, VOC, and HAP. Components include: valves, pumps, pressure relief valves, connectors, flanges, and, open-ended lines. These components are ancillary equipment to many larger equipment source types including: headers, separators, heaters, filters, engines, compressors, dehydration units, and storage tanks. Data Collection The ICR provided operators with the option to report average fugitive component counts for single and co-located well-sites. In the absence of ICR provided component counts, the AQP relied on assumed component counts, as detailed below. Assumptions Fugitive component counts were assumed based on component counts for natural gas production contained in the Canadian Association of Petroleum Producers (CAPP) document titled Guide to Calculating Greenhouse Gas Emissions.22 Component counts for single and co-located well-site locations are displayed below in Figure 54. 22 Canadian Association of Petroleum Producers. (2003). Guide to Calculating Greenhouse Gas Emissions. Retrieved from http://www.capp.ca/publications-and-statistics/publications/241974 64 Figure 54 – Assumed Fugitive Emission Component Counts at Single and CoLocated Natural Gas Well-Sites on the Southern Ute Indian Reservation Assumed Component Counts for Well-Site Locations on the Southern Ute Indian Reservation Component Type-Service Valves-Gas/Vapor Connectors-Gas/Vapor Open-Ended LinesGas/Vapor Component count for a Single well 16 60 Component count for Two co-located wells 32 120 Component count for Three Colocated wells 48 180 Component count for Four Colocated wells 64 240 3 6 9 12 Emission Calculation Methodology VOC and HAP Emission Calculations: VOC and HAP emissions from equipment leaks and fugitive emissions were calculated using the average emission factor approach and the gas/vapor total organic compound (TOC) emission factors for oil and gas production from Table 2-4 of Chapter 2.3 of EPA AP-42. The TOC emission factor for gas/vapor was chosen as the most representative of production on the Reservation in CY2015 and is the most conservative emission factor available. TOC emissions were calculated by multiplying the gas/vapor emission factor by component counts from Tab 1 of the CAPP, the component count that corresponds to the number of wells and typical well-site equipment configurations reported by each recipient of the ICR, and an assumed 8,760 hours of annual operation. VOC and HAP emissions were then derived by multiplying the TOC emissions by the VOC and HAP molecular weight fraction percentages of an assumed extended natural gas analysis for the Reservation. If component counts were provided by operators in the ICR, emissions for their company’s productions were calculated using their reported counts in place of the CAPP component counts. GHG Emission Calculations: GHG emissions from equipment leaks and fugitive emissions were calculated using the equipment leak by population count methodology and equation W-32A of Subpart W of 40 CFR Part 98 (Subpart W). Input values for the W-32A equation included the emission factors for gas leakage from western U.S. gas service from Table W-1A of Subpart W, the component counts provided in the ICR, the population emission factors listed for equipment types in Tables W-1A and W-4 through W-7 of Subpart W, an assumed 8,760 hours of annual operation, and the methane and CO2 molecular weight percentage rates from an assumed extended natural gas analysis. Final GHG values were converted from volume to mass using equation W-36 of Subpart W and the gas densities from §98.233(u)(2)(v) of Subpart W. 65 Example Calculations VOC and HAP Emission Calculation Methodology: VOC or HAP Emissions = AP-42 Average Emission Factor for Gas Valves x API Compendium Generic Valve Count x VOC or HAP Percent Weight= lb/hr VOC or HAP emissions VOC Emissions (lb/hr) = (0.0099 lb/hr/gas valve) x (400 valves) x (0.06% VOC) = 0.0026lb/hr VOC Emissions (tpy) = (0.0026 lb/hr) x (8760 hr/yr) x (Ton/2000 lb) = 0.0112 tons/year GHG Emission Calculation Methodology – Equation W-32A of 40 CFR 98 Subpart W: GHG Emissions (scf/yr) = (Count) x (Efs,e) x (GHGi) x (Te) Where: Count = Total number of the emission source type at the facility. EFs,e = Population emission factor for the specific emission source type, as listed in Tables W-1A and W-4 through W-7 GHGi = Concentration of GHG (CH4 or CO2) in produced natural gas Te = Average estimated time that each emission source type associated with the equipment leak emission was operational in the calendar year, in hours Example Methane Calculation for Valves: scf/yr = (50 x 0.121) x (0.922564147) x (8760) = 48,894.05scf/yr To convert from scf/yr to scf/hour divide by 8760 Scf/hr = 48,894.05/8760 =5.58 To derive an scf/hr amount, divide scf/yr by annual hours of operation Volume to Mass Equation - Equation W-36 of 40 CFR 98 Subpart W Massi = (Es,i) x (pi) x 10^-3 Where: Massi = Mass emissions in metric tons Es,I = Volumetric emissions at standard conditions, in cubic feet Pi = Density of GHG 66 Equation altered to give answer in lb/hr Mass I = (Es,I) x (pi) x (lb/kg) Example: lb/hr = 5.58 x 0.0192 x 2.20462 = 0.23 lb/hr To calculate annual emissions in ton per year, multiply lb/hr rate by 8760 hours and divide by 2,000 lb/ton tpy Methane = (0.23 x 8760)/2,000 = 1.03 Emissions Volatile organic compound, HAP and GHG emissions from equipment leak and fugitive emission sources located at non-registered oil and gas sources on the Reservation for calendar year 2015 are displayed below in Figure 55. Figure 55 – 2015 Emissions of VOC, HAP, and GHG from Equipment Leaks and Fugitive Emission Sources at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 2015 Emissions from Equipment Leaks and Fugitive Emission Sources at Non-registered Oil and Gas Sources in Tons per Year Pollutant VOC HAP CO2e Emission Totals 252.9 15.1 209,593 G. Natural Gas Driven Pneumatic Devices Description of Sources Natural gas-driven pneumatic controllers and pumps are used in the oil and natural gas industry for maintaining liquid levels, pressures, pressure differentials, and temperature. Many devices are designed to leak, or “bleed”, natural gas and in doing so emit natural gas containing methane, CO2, VOC, and HAP. Pneumatic devices are classified as high or low continuous bleed controllers, intermittent bleed controls, or zero bleed controllers. Data Collection The AQP assigned an assumed value for the average number of pneumatic devices located at a single wellsite from the 2014 Environmental Science and Technology report titled Methane Emissions from Process Equipment at Natural Gas Production Sites in 67 the United States.23 The assumed pneumatic device count value was provided in the ICR and operators were provided the opportunity to override the assumed value with values more representative of their operations. Emission Calculation Methodology Pneumatic device emissions were calculated by applying the generic natural gas emission factors and supply pressure coefficients found in EPA’s April 2014 Report for Oil and Natural Gas Sector Pneumatic Devices to the AQP’s assumed average device count or average device counts reported in the ICR. Example Emission Calculation: lb/hr = Count x Bleed Rate x R x MW x Y Where: Count = total number of devices Bleed Rate = bleed rate from device (scf/hr/device) R = Universal gas constant (lb-mol/379.3scf) MW = molecular weight of the component Y = volume fraction of component in the vented gas Example for Methane lb/hr = 2695 x 58.5 x 1/379.3 x 16.01 x 92% = 577.2 lb/hr tpy = lb/hr x OH/2000 Where: lb/hr = emission rate in pounds per hour OH = annual operating hours 2000 = pounds per ton 23 Allen, D. (2014). Methane Emissions from Process Equipment at Natural Gas Production Sites in the United States: Pneumatic Controllers. Environmental Science & Technology, 49, 633-640. Retrieved from http://pubs.acs.org/doi/pdf/10.1021/es5040156 68 tpy methane = 577.2 x 8760/2000 = 2528.1 tpy Emissions Volatile organic compound, HAP, and GHG emissions from natural gas driven pneumatic devices on the Reservation during 2015 are displayed below in Figure 56. Figure 56 - 2015 Volatile Organic Compound, HAP, and GHG Emissions from Natural Gas Driven Pneumatic Devices at Non-Registered Oil and Gas Sources on the Southern Ute Indian Reservation in Tons per Year 2015 Emissions from Natural Gas Driven Pneumatic Devices in Tons per Year Pollutant VOC HAP CO2e Emission 129.5 7.8 150,493.2 Totals H. Natural Gas Blowdowns Description of Sources Natural gas blowdowns are intentional and unintentional gas releases during maintenance, routi [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/tribal%3Asouthern_ute%3Ae484a71ea4393422. Public record. Not legal advice.