Southern Ute Indian Tribe

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Priority Climate Action Plan

April 1, 2024

Southern Ute Indian Tribe Air Quality Division

Project Contact: Daniel Powers

dpowers@southernute-nsn.gov

970-563-2265

This project has been funded wholly or in part by the United States Environmental Protection Agency (EPA) under

assistance agreement 5D-00133400 to the Southern Ute Indian Tribe Air Quality Division. The contents of this

document do not necessarily reflect the views and policies of the EPA, nor does the EPA endorse trade names or

recommend the use of commercial products mentioned in this document.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Contents

Executive Summary ................................................................................................................. 1

Introduction ............................................................................................................................. 4

2.1

Climate Pollution Reduction Grant Overview ................................................................. 5

2.2

Priority Climate Action Plan Overview ........................................................................... 5

2.3

Approach to Developing the PCAP ................................................................................. 5

2.4

Scope of the PCAP ........................................................................................................... 6

Tribal Organization and Considerations .................................................................................. 8

3.1

PCAP Management and Development Team................................................................... 8

3.2

Special Considerations ..................................................................................................... 8

3.3

Collaborations .................................................................................................................. 8

PCAP Elements ..................................................................................................................... 10

4.1

GHG Inventory ............................................................................................................... 10

4.1.1

Scope ....................................................................................................................... 10

4.1.2

Data Collection ....................................................................................................... 10

4.1.3

GHG Accounting Method ....................................................................................... 11

4.1.4

GHG Emission Results by Sector- Oil and Gas...................................................... 11

4.2

GHG Reduction Measure – Voluntary Administration and Implementation of CAA

Programs and Standards ............................................................................................................ 12

4.2.1

Other GHG Emission Reduction Measures Administered by AQD ....................... 15

4.2.2

Other GHG Emission Reduction Measures Occurring on the Reservation ............ 16

4.3

GHG Emissions Projections and Reduction Targets ..................................................... 19

4.4

Benefits Analysis............................................................................................................ 21

4.5

Review of Authority to Implement ................................................................................ 24

4.6

Identification of Other Funding Mechanisms ................................................................ 25

4.7

Workforce Planning Analysis ........................................................................................ 25

Next Steps .............................................................................................................................. 26

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Figures

Figure 1. Southern Ute Indian Reservation..................................................................................... 7

Figure 2. PCAP Development Organization Chart ......................................................................... 8

Figure 3. CAA Enforcement at Title V Sources by Calendar Year .............................................. 22

Tables

Table 1: Components of the Tribe’s Priority Measure for Reducing GHG Emissions ................ 13

Table 2. TMNSR and FIP Implementation, NSPS Adoption, and TIP Development Summary . 14

Table 3. Summary of AQD GHG Reduction Measures ............................................................... 15

Table 4. Summary of Other GHG Emission Reduction Projects.................................................. 17

Table 5. Emissions Projections and Reductions Targets. ............................................................. 21

Table 6: 2020 Criteria Pollutant and HAP Emissions from True Minor Sources (tons) .............. 23

Table 7. VOC Estimated Projections and Reductions .................................................................. 23

Appendices

Appendix A: 2020 EI

Appendix B: CARB Report

Appendix C: Southern Ute Indian Tribe Reservation Air Code

iii

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Abbreviations

AQ Planner

AQD

AQDH

AQDM

AQTM

ASAP

CAA

CAPs

CARB

CCAP

CFR

CH4

CMS

CO2

CO2e

Commission

Cottonwood

CPRG

DOE

EPA

FIP

FLIGHT

GAP

GHG

HAPs

HFCs

IRA

LDAR

Lidar

MACT

MERP

Air Quality Planner

Air Quality Division

Air Quality Division Head

Air Quality Division Manager

Air Quality Technical Manager

as soon as possible

Clean Air Act

Criteria Air Pollutants

California Air Resources Board

Comprehensive Climate Action Plan

Code of Federal Regulations

methane

compliance monitoring strategy

carbon monoxide

carbon dioxide

carbon dioxide equivalent

Southern Ute Indian Tribe and State of Colorado Environmental Commission

Cottonwood Consulting LLC

Climate Pollution Reduction Grant

Calendar Year

Department of Energy

emissions inventory

US Environmental Protection Agency

electric vehicle

Federal Implementation Plan for Managing Air Emission from True Minor

Sources in Indian Country in the Oil and Natural Gas Production and Natural Gas

Processing Segments of the Oil and Gas Sector

Facility Level Information on Greenhouse Gases Tool

fiscal year

General Assistance Program

Grants Coordinator

Greenhouse Gas

Hazardous Air Pollutants

hydrofluorocarbons

Inflation Reduction Act

Leak Detection and Repair

Light Detection and Ranging

Maximum Achievable Control Technology

Methane Emissions Reduction Program

millions

megawatt

Southern Ute Indian Tribe Priority Climate Action Plan

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N2O

NAAQS

NESHAP

NF3

NOx

NSPS

PCAP

PFCs

PM2.5

PM10

PTE

QAPP

RAC

Red Cedar

Red Willow

Reservation

SAQCS

SF6

SO2

TBD

TIP

TMNSR

tpy

Tribe

VOC

nitrous oxide

National Ambient Air Quality Standards

National Emission Standards for Hazardous Air Pollutants

nitrogen trifluoride

nitrogen

New Source Performance Standards

Priority Climate Action Plan

perfluorocarbons

particulate matter 2.5 micrometers or less in diameter

particulate matter 10 micrometers or less in diameter

potential to emit

Quality Assurance Project Plan

Reservation Air Code

Red Cedar

Red Willow Production Company

Southern Ute Indian Reservation

Senior Air Quality Compliance Specialist

sulfur hexafluoride

sulfur dioxide

to be determined

Tribal Implementation Plan

Tribal Minor New Source Review

tons per year

Southern Ute Indian Tribe

volatile organic compounds

1 Executive Summary

The purpose of this Priority Climate Action Plan (PCAP) is to provide a comprehensive and

detailed analysis of the short-term, high-priority, and implementation ready greenhouse gas (GHG)

emissions reductions measures that could be implemented by the Southern Ute Indian Tribe (Tribe)

Air Quality Division (AQD) within the boundaries of the Southern Ute Indian Reservation

(Reservation; see Figure 1).

The primary priority measure being considered in the PCAP is the Tribe’s proposal to reduce GHG

and volatile organic compound (VOC) emissions from minor sources of oil and gas on the

Reservation through the Tribe’s voluntary administration and implementation of several Clean Air

Act (CAA) programs and standards.

The voluntarily administered CAA programs would be the Federal Minor New Source Review

Program in Indian country, 40 CFR Part 49, Subpart C, Sections 49.151 through 49.164 (TMNSR),

and the Federal Implementation Plan for Managing Air Emissions from True Minor Sources in

Indian Country in the Oil and Natural Gas Production and Oil and Natural Gas Processing

Segments of the Oil and Natural Gas Sector, 40 CFR Part 49, Subpart C, Sections 49.101 through

49.105 (FIP).

The voluntarily implemented standards are the New Source Performance Standards (NSPS)

Subparts OOOO, OOOOa, and OOOOb. These standards were promulgated by the US

Environmental Protection Agency (EPA) to establish standards designed to reduce GHG and VOC

emissions from the oil and gas sector. Lastly, the Tribe is proposing the development and EPA

approval of a Tribal Implementation Plan (TIP) for adoption of the Emissions Guidelines

established in NSPS OOOOc.

The PCAP outlines the data collection methodology and analyses used to identify the emissions

sources of interest within the Reservation and a mitigation plan that could be implemented to

reduce emissions of GHG, and the co-benefit pollutant, VOCs through the Tribe’s voluntary

administration and implementation of these CAA programs and standards.

The Tribe's PCAP will focus on the industrial sector, as identified in the Climate Pollution

Reduction Grant (CPRG), and specifically, the oil and gas sector. The industrial sector on the

Reservation includes two landfills, and nearly 3,000 oil and gas sources ranging from small oil and

gas pads to large gas processing facilities. Collectively, oil and gas sources are the largest emitters

of GHG, VOC, hazardous air pollutants (HAPs), and criteria air pollutants (CAPs), on the

Reservation.

For the purposes of the PCAP, emissions data will be sourced from the AQD's existing calendar

year (CY) 2020 comprehensive emissions inventory, which includes emissions data from every

source sector on the Reservation including “major” and “minor” oil and gas and landfill point

sources, nonpoint oil and gas and landfill sources, mobile sources, wildfires, residential heating,

airports and aviation fueling, biogenic sources, and natural occurring methane emissions from the

Fruitland Coal outcrop. Reservation-wide emission totals for CY 2020 were 11,342,510.62 metric

tons of GHG emissions measured in carbon dioxide equivalent (CO2e), 8,773.01 tons of VOCs,

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

19,743.58 tons of oxides of nitrogen (NOx), 80.94 tons of sulfur dioxide (SO2), 396.57 tons of

particulate matter 10 micrometers or less in diameter (PM10), 146.02 tons of particulate matter 2.5

micrometers or less in diameter (PM2.5), 18,767.33 tons of carbon monoxide (CO), and 1,527.28

tons of total HAP.

Minor oil and gas point sources are the focus of this PCAP, because this source category is currently

the third most significant source of GHG emissions on the Reservation at 1,568,843 metric tons

per year (tpy) of CO2e, and the most significant source category subject to federal CAA permit

programs (TMNSR and the FIP) which could be administered by the Tribe through an EPA

delegation. Title V major oil and gas sources are the largest source of GHG emissions on the

Reservation at GHG at 2,124,765 tpy of CO2e, and sources below the TMNSR and FIP program

thresholds are the second largest GHG emitters at 1,618,204 tpy CO2e. Title V major sources and

sources below TMNSR and FIP program thresholds are not being considered in this PCAP because

the Tribe has previously implemented measures to reduce emissions from these sources, including

voluntary administration of CAA programs to regulate these sources, or because the sources are

not subject to federal CAA permit programs, and are therefore not easily regulated by the Tribe. A

2012 EPA rulemaking provided the Tribe with a full delegation of the Title V operating permit

program, implementation of the NSPS, National Emissions Standards for Hazardous Air Pollutants

(NESHAP) and Maximum Achievable Control Technology (MACT) standards. A 2013 EPA

rulemaking granted the Tribe automatic delegation of the standards under CAA §§111 and 112.

The Tribe’s efforts to administer the TMNSR program and FIP are well underway, with the Tribe

having applied to EPA in April of 2020 requesting conditional approval for administrative

delegation of the TMNSR permitting program and FIP. The Tribe and EPA are currently nearing

completion of a delegation agreement between the Tribe and the EPA for these programs and it’s

a goal of EPA to publish a rulemaking in 2024 to make the agreement final.

The decision for the Tribe to apply for delegation of the TMNSR and FIP followed an extensive

stakeholder outreach process from 2017 through 2019, which included the regulated community,

the public, and other governmental agencies, including La Plata County, Archuleta County, the

State of Colorado, EPA, and Tribal Council. This process entailed numerous public meetings

tailored towards regulated industry and multiple public Tribe/State of Colorado Environmental

Commission (Commission) meetings to evaluate the project options with all interested parties and

stakeholders.

Central to the Tribe’s PCAP priority measure is the Tribe’s plan to assess compliance with the

TMNSR, FIP, and NSPS OOOO series rules through increased compliance oversight of the

approximately 250 true minor oil and gas sources and six synthetic minor oil and gas sources on

the Reservation. The Tribe is certain, due to its previous experience implementing CAA programs

and standards, that these activities would lead to increased compliance, and in turn, a reduction of

GHG, VOC, and other harmful air pollutants. Under the Tribe’s proposal, true minor sources (e.g.

FIP sources) would be inspected on a five-year basis and synthetic minor sources (e.g. TMNSR

sources) would be inspected on a two-year basis through an EPA-approved compliance monitoring

strategy (CMS). Under the current EPA administration of the TMNSR program and FIP, true

minor sources are not inspected, and synthetic minor sources are inspected once every five years.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

The Tribe’s proposed inspection frequency is consistent with the CMS inspection frequency of the

State of Colorado and New Mexico air quality jurisdictions adjacent to the Reservation.

In addition, the Tribe plans to investigate oil and gas sources identified in the Tribe’s emissions

inventory that may be operating above TMNSR or Title V operating permit program emission

thresholds without a federal or Tribal permit. The Tribe will work to get these sources into

compliance through the Tribe’s existing CAA authorities under 40 CFR Part 49 and Part 70, and

CAA §§§§111, 112, 113 and 114.

Furthermore, the Tribe intends to evaluate and include in the PCAP, the Comprehensive Climate

Action Plan (CCAP), and emissions inventories potential emissions reductions that may result

from several projects and emissions quantifications activities being undertaken on the Reservation

by the Tribe’s business entities and non-Tribal private industry. These projects are further

described below in Sections 4.2 and 4.6.

All activities completed under the CPRG will (1) be the responsibility of the Tribe’s AQD as the

lead agency, (2) be performed within the exterior boundaries of the Reservation in southwest

Colorado and (3), begin in CY 2025 and implemented through the end of the grant cycle in CY

2030.

To demonstrate the GHG and co-pollutant emissions reductions that could be realized through the

PCAP measures, the Tribe has estimated emissions projections and reduction targets from CY

2025 through CY 2050. To make this demonstration, the Tribe began by projecting emissions

forward based on a per facility emissions estimate, determined using the CY 2020 emissions

inventory report, and applying a target GHG reduction of 29 percent (%) from a report developed

by the California Air Resources Board (CARB) titled “CARB’s Oil and Gas Methane Regulation

2018 Annual LDAR Summary” which estimates GHG emission reductions resulting from

implementation of leak detection and repair programs in California. The Tribe has estimated that

one true minor source has a potential to emit (PTE) 520.67 CO2e metric tons per year. Between

the years of 2025 and 2030, the AQD expects to reduce GHG emissions from minor oil and gas

sources by approximately 247,482 metric tons of CO2e. The Tribe has estimated that 4.3 new

minor sources will be developed every year through 2050 and that the PCAP priority measure will

reduce GHG emissions from true minor sources by approximately 654.3 metric tons per year. The

AQD also estimates similar reductions from the six synthetic minor sources; however, for

simplicity, these sources are being grouped into the true minor source category, despite them being

larger sources with potentially higher emissions and possible emission reductions.

The Tribe’s voluntarily administration of these CAA programs and standards and the

accompanying compliance strategy would result in significant improvements to the Tribe’s air shed

and reduce the impacts of climate change caused by GHG emissions. This will, in turn, help

mitigate several potential impacts of climate change that are currently observed on the Reservation

(such as increased droughts and forest fires) and will significantly reduce climate change impacts

for future generations.

If the Tribe is successful in obtaining these EPA delegations, it would be the first instance of a

federally recognized Tribe in the United States to voluntarily receive TMNSR and FIP delegation

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

and to implement a minor source inspection schedule that will ensure compliance at regulated and

potentially unregulated polluting sources on a Reservation. In addition, this delegation will

improve the Tribe’s understanding of emissions sources on the Reservation and enhance emissions

data collection from these sources. This delegation will also provide other federally recognized

tribes an example that can be used to seek delegation of the TMNSR programs and FIP from EPA

in their own jurisdictions.

2 Introduction

The Reservation is located in the southwestern region of Colorado bordering the state line of New

Mexico. This semi-arid and high desert landscape is vulnerable to the effects of climate change

and warmer temperatures. An increase in wildfires, droughts, and excessive heat waves are just a

few of the harmful impacts felt by Tribal members, local residents, and the environment. To

mitigate these effects, the Tribe applied for and received a Climate Action Planning Grant to

develop a long-term strategy to reduce the effects of climate change by decreasing GHG emissions

within the exterior boundaries of the Reservation.

The Tribe is dedicated to ensuring that the air on the Reservation remains clean and safe for Tribal

members and residents, now and into the future. The Tribe does this through monitoring of air

quality, CAA permitting and compliance monitoring of major air pollution sources, emissions

inventories, and continued research of air pollution and its sources. By reducing GHG and other

harmful air pollutant emissions, the Tribe will reduce the harmful effects of climate change related

to global temperature rise and improve air quality for Tribal members, residents of the Reservation,

and the environment.

The Tribe has developed this PCAP to address near-term, high-priority, implementation-ready

measures to reduce GHG and VOC emissions on the Reservation. The PCAP is focused on the oil

and gas (industrial) sector, which is the highest-emitting sector on the Reservation.

As outlined in the Executive Summary, the Tribe proposes to reduce GHG emissions on the

Reservation through the Tribe’s voluntary administration and implementation of several CAA

programs and standards.

Furthermore, the Tribe intends to describe potential GHG emissions reductions projects that may

be undertaken by Tribal business entities (separate from Tribal government) and non-Tribal private

industry.

Based on data from the EPA's Environmental Justice Screening and Mapping Tool, EJScreen, the

Reservation and Tribal members are an environmental justice population. Creation of high-quality

jobs in environmental justice populations is a high priority of EPA and the Tribe. The Tribe is

dedicated to being a premier employer in the southwestern region of Colorado. The Tribe offers

competitive wages and a significant employee benefits package that includes paid holidays, health

insurance, annual and sick leave accrual, dental, vision, life insurance, and retirement plans for

full-time employees (further discussed in section 4.7).

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

2.1 Climate Pollution Reduction Grant Overview

Through the Inflation Reduction Act of 2022 (IRA), Congress provided many tools to pursue GHG

pollution reductions, including the CPRG program. In implementing this and many other programs

under the IRA, the EPA seeks to achieve three broad objectives:

•

Tackle damaging climate pollution while supporting the creation of good jobs and lowering

energy costs for families.

Accelerate work to address environmental injustice and empower community-driven

solutions in overburdened neighborhoods.

Deliver cleaner air by reducing harmful air pollution in places where people live, work,

play, and go to school.

In line with this strategy, EPA is committed to supporting the development and expansion of tribal,

state, territorial, and local climate action plans, and the implementation of investment-ready

projects to reduce GHG pollution.

2.2 Priority Climate Action Plan Overview

The Tribe received a CPRG planning grant award in 2023 and is utilizing that award to develop a

PCAP. The planning grant provides flexible support to design climate action plans that incorporate

a variety of measures to reduce GHG emissions from across their economies in key sectors.

The PCAP will help the Tribe to:

1. Improve their understanding of current and future GHG and other harmful pollutant

emissions,

2. Identify priority strategies to reduce these emissions and the potential other benefits of

those strategies, and

3. Engage stakeholders in an emissions reduction planning process, including development

of the CCAP.

Development of the PCAP will also support the Tribe's CPRG implementation grant application

and will inform the CCAP, which is due at the close of the grant period (CY 2030).

The PCAP includes the elements listed below:

•

GHG inventory.

Analysis of GHG emissions reductions that would be achieved through implementation of

the proposed GHG reduction measure.

Benefits analysis.

A review of the Tribe's authority to implement the proposed GHG reduction measure.

2.3 Approach to Developing the PCAP

Multiple approaches and methodologies have been used to develop this PCAP, including

leveraging of the expertise and technical capacities at the Tribe’s disposal.

The Tribe prepares emissions inventories for air emission sources within the Reservation

boundaries. Comprehensive inventories of emissions from all quantifiable point, nonpoint sources,

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

mobile, and fire events are completed every three years and inventories of large point source

emissions are completed annually. The emissions inventory utilized by the PCAP was developed

for CY 2020 emissions.

Based on the results of the 2020 Emissions Inventory (2020 EI), the oil and gas sector is the

highest-emitting sector on the Reservation and minor oil and gas sources are the third largest

emitters within the sector. The Tribe sought to develop GHG reduction measures that would reduce

emissions from oil and gas facilities. The Tribe prioritized measures that are ready for

implementation and for which the Tribe will have the authority to implement.

The Tribe engaged stakeholders and the public in other, closely related projects. Additionally, the

Tribe met with stakeholders early in the CPRG planning grant process to develop an understanding

of other GHG reduction measures and projects underway on the Reservation.

2.4 Scope of the PCAP

All lands located within the exterior boundaries of the Reservation are under the jurisdiction of the

Reservation Air Program, which was established in 2004 by the Intergovernmental Agreement

between the Southern Ute Indian Tribe and the State of Colorado Concerning Air Quality Control

on the Southern Ute Indian Reservation (Pub. L. No. 108-336, 118 Stat. 1354). The Reservation

Air Program is under the oversight of the Commission, which serves as the policy-making and

administrative review authority for the Reservation Air Program.

The Reservation is located in southwestern Colorado and covers 682,590 acres in three counties

(La Plata, Archuleta, and Montezuma), bordering New Mexico to the south (Figure 1). The Tribe

and/or its members own approximately 320,000 acres, while the remaining land 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.

All GHG emissions reduction activities proposed in the PCAP will be performed within the

exterior boundaries of the Reservation.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Figure 1. Southern Ute Indian Reservation

3 Tribal Organization and Considerations

The AQD is a division of the Environmental Programs Department of the Southern Ute Tribal

Government. The Southern Ute Indian Tribal Council is the governing body of the Tribal

Government, as established by the passage of the Indian Reorganization Act by Congress.

The AQD’s staff positions include an Air Quality Division Head (AQDH), two Air Quality

Division Managers (AQDMs), an Air Quality Planner (AQ Planner), three Air Quality Compliance

Specialists, a Permit Writer, an Enforcement Coordinator, and an Ambient Air Quality Specialist.

3.1 PCAP Management and Development Team

The PCAP was prepared at the direction of Tribal Council by AQD staff with assistance from a

consultant, Cottonwood Consulting LLC (Cottonwood), who was contracted to assist the AQD

with the development of planning grant deliverables, including a quality assurance project plan

(QAPP), the PCAP, and the CCAP.

A PCAP development organization chart is included as Figure 2.

Figure 2. PCAP Development Organization Chart

Tribal Council

Executive Officer

Environmental Programs Director

Mark Hutson

Air Quality Division Head

Danny Powers

Air Quality Planner

Michael Kirsch

Cottonwood Staff

Emma Millar

3.2 Special Considerations

The Tribe currently implements and administers a Title V operating permit program (EPA 40 Code

of Federal Regulations [CFR] Part 70) for Title V sources within the exterior boundaries of the

Reservation. To further improve air quality on the Reservation, the Tribe has requested EPA

authority to implement and administer the TMNSR program and FIP on the Reservation. This

authority will allow the Tribe to regulate approximately 250 true minor oil and gas sources and six

synthetic minor sources within the Reservation. These sources are currently permitted and

inspected by the EPA; however, the EPA has been unable to conduct compliance inspections at

true minor sources due to resource constraints, and the six synthetic minor sources are only

inspected on a five-year basis. The Tribe anticipates that administering these programs, including

issuance of permits and conducting inspections, will result in higher levels of compliance with

applicable regulations and a subsequent reduction in GHG and VOC emissions.

3.3 Collaborations

From 2017 through 2019, the Tribe undertook an extensive stakeholder outreach process to

determine the best option for the Tribe’s regulation of minor oil and gas sources within the

Reservation boundaries. The stakeholders included the regulated community, the public, and other

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

governmental agencies, including La Plata County, Archuleta County, the State of Colorado, EPA,

and Southern Ute Tribal Council. This process entailed numerous public meetings tailored towards

the regulated industry and multiple public Commission meetings to evaluate the project options

with all interested parties and stakeholders.

For the purpose of the CPRG, the AQD includes agenda item discussions at the bi-annual

Commission meetings, and will conduct additional public stakeholder meetings as warranted, to

discuss proposed and additional measures that could be taken to reduce GHG emissions. These

Commission agenda item discussions and public meetings provide the opportunity for stakeholders

to offer input on how to meet the PCAP and CCAP goals most effectively, including additional

potential GHG reduction measures on the Reservation from source sectors other than oil and gas.

Discussions also include ideas of how to develop quality GHG emission inventories and the

sharing of draft items being prepared for the CPRG implementation phase. The Tribe also engages

with oil and gas operators and energy development companies on the Reservation to quantify their

emission reduction measures in the Tribe’s emissions inventories.

All Commission meeting announcements, draft agendas, and final documents are available on the

Tribe’s AQD websites and published in local newspapers, when necessary. Virtual meeting

options are provided to the public and stakeholders for all in-person meetings. The next

Commission meeting is scheduled for April 24, 2024.

Following receipt of the CPRG planning grant, the AQD also met with other entities, including

Red Willow Production Company (Red Willow), Red Cedar Gathering Company (Red Cedar),

Department of Energy (DOE), and Aka Energy Group, that operate on the Reservation and are

implementing emissions reduction projects on the Reservation. Some information about those

projects is included in 4.2.2 and more detail will be included in the CCAP.

In addition to Commission meetings and coordination with other entities, the Tribe has solicited

feedback from Tribal members, Tribal employees, and residents of the Reservation via a survey

linked to the Tribe’s AQD website. The survey consists of a series of questions related to GHG

emissions and proposed GHG reduction measures. The survey also includes a comment section to

solicit other input. Results and analysis of the survey results will be included in the CCAP. Based

on the feedback received from that survey, the Tribe may conduct virtual or in-person meetings to

solicit additional public input. The Tribe may also host webinars or in-person meetings to explain

proposed GHG reduction measures.

For the purposes of increasing public knowledge of the CPRG, soliciting input on PCAP and

CCAP developing, and posting draft and final documents, a new CPRG webpage has been

developed by the Tribe. This website includes information about the CPRG and PCAP/CCAP

development, and a link to the aforementioned survey to allow the public to actively participate in

the planning process. All documents related to the CPRG will be posted once finalized and

approved by EPA and the Tribe.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

4 PCAP Elements

Section 4 includes a GHG inventory, a list of implementation-ready measures to reduce GHG

pollution, an analysis of GHG emissions reductions, a benefits analysis, and a review of the Tribe’s

authority to implement to proposed GHG reduction measure.

4.1 GHG Inventory

The GHG inventory included in the PCAP was compiled using existing data derived from the

Tribe’s Comprehensive Emissions Inventory developed for CY 2020 and is included as Appendix

A. The 2020 EI was developed to determine emissions estimates for all quantifiable air emission

sources located within the Reservation's exterior boundary. The emissions data presented in the

2020 EI have been organized by source category and pollutant. The 2020 EI is used for air quality

planning purposes, including development of air quality regulations targeted at ozone precursors

for maintaining attainment with the National Ambient Air Quality Standards (NAAQS), emissions

modeling, Title V permitting fee analysis, and to monitor GHG emissions within the Reservation.

4.1.1 Scope

The geographic scope of the 2020 EI is the exterior boundary of the Reservation. The total area

covered by the inventory is approximately 682,590 acres, which encompasses all land within the

external boundaries of the Reservation.

The primary air pollutants included in the 2020 EI are NOx, CO, PM10, PM2.5, VOC, HAP, and

GHG emissions (carbon dioxide [CO2], methane [CH4], nitrous oxide [N2O], hydrofluorocarbons

[HFCs], perfluorocarbons [PFCs], sulfur hexafluoride [SF6], and nitrogen trifluoride [NF3])

measured in CO2e. The emissions inventory was prepared according to the EPA Level II emission

inventory guidelines of using measured data when available or data and emissions factors from

reputable sources when measured data were not available.

4.1.2 Data Collection

The sources included in this emissions inventory were organized according to source type and size.

These 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

b. Registered minor FIP sources

3) Municipal solid waste landfills, and

4) Airports.

B. Non-point Sources

1) Small oil and gas sources,

2) Fruitland Coal Outcrop natural gas seeps,

3) Gasoline stations,

4) Aviation gasoline dispensing,

5) Gravel pits,

6) Residential heating, and

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

7) Agricultural burning.

C. Mobile Sources

1) On-road vehicles, and

2) Non-road equipment.

D. Events

1) Fire events (wildland fires and prescribed burns).

Oil and natural gas production is the dominant industry on the Reservation and oil and gas sources

were identified as the primary source of GHG emissions on the Reservation. Emissions data for

these sources were collected directly from source operators through annual emission inventories,

registrations from sources under the EPA-administered TMNSR program, and a CAA Section 114

information collection request issued by the Tribe in June 2021. Data for other sources were

collected from various reputable state, local, and federal data sources such as the Motor Vehicle

Emission Simulator, Landfill Gas Emissions Model, and Facility Level Information on

GreenHouse gases Tool (FLIGHT) tools developed by the EPA. More detail about data collection

and data quality are included in the 2020 EI.

The 2020 EI inventory also covers emissions from landfills, nonpoint sources, mobile sources,

wildfires, biogenic sources, and naturally occurring natural gas emissions from the Fruitland Coal

geologic outcrop. Nonpoint sources include agricultural burning, residential heating, gravel pits,

gas stations, and airports. Airport emissions include emissions from landing, take-off, and aviation

fueling. Mobile sources include on-road vehicles and non-road engines including lawn equipment,

recreational vehicles, agricultural equipment, construction equipment, etc.

4.1.3 GHG Accounting Method

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 operators

through required emission reports submitted by each source to the Tribe. Actual emissions data

were available for all 35 Title V oil and gas sources. GHG emissions, reported as CO2e, were

obtained from fee calculation worksheets (if provided) and if not, the PTE listed in their most recent

Title V permit renewal was used and cross checked with EPA FLIGHT at

https://GHGdata.epa.gov/GHGp/main.do. Data for minor oil and gas sources were collected

directly from source operators through registrations from sources under the EPA-administered

TMNSR program and FIP. Data for oil and gas sources below the emission thresholds of the

TMNSR and FIP programs were obtained using a CAA Section 114 information collection request

issued by the Tribe in June 2021. The Tribe used this information to calculate emissions using

actual production data from the Reservation and the best available emissions factors and

assumptions. This data collection and calculation methodology adheres to the EPA Level II EI

guidelines for utilizing measured data when available and the best available emissions factors and

assumptions when measured data is not available.

4.1.4 GHG Emission Results by Sector- Oil and Gas

As of 2020, there were a total of 2,860 oil and gas production sources operating on the Reservation.

These sources consisted of 35 sources operating under Tribe-issued Title V operating permits, six

sources operating under EPA TMNSR synthetic minor permits, 238 true minor sources operating

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

under EPA FIP registrations, and 2,582 non-point sources with emissions below the TMNSR and

FIP program thresholds, referred to in the 2020 EI as “small oil and gas sources.”

Reservation-wide emission totals for CY 2020 were 19,743.58 tons of NOx, 8,773.01 tons of VOC,

80.94 tons of SO2, 396.57 tons of PM10, 146.02 tons of PM2.5, 18,767.33 tons of CO, 1,527.28 tons

of total HAP, and 11,342,510.62 metric tons of GHG emissions measured in CO2e.

4.2

GHG Reduction Measure – Voluntary Administration and Implementation

of CAA Programs and Standards

The Tribe has demonstrated through several emissions inventories that the oil and gas industry is

the most significant source of GHG and other air pollution on the Reservation. The Tribe

anticipates oil and gas production and development to continue on the Reservation, and within the

greater Four Corners region, for several more decades. For this reason, it is an important function

of the Tribe to make efforts to mitigate these emissions in an environmentally and economically

efficient manner. To mitigate these emission impacts, the Tribe has developed a GHG reduction

measure that will have significant and lasting reductions in GHG emissions on the Reservation,

which will result in associated climate and health benefits.

The GHG reduction measure being proposed by the Tribe is the Tribe’s voluntary administration

and implementation of several CAA programs and standards, including (1) the TMNSR program;

(2) the minor oil and gas source FIP; (3) implementation of the NSPS OOOO, OOOOa, and

OOOOb standards through the Tribe’s existing NSPS authority; and (4) development of a TIP to

adopt the Emissions Guidelines of NSPS OOOOc. Compliance with all of these measures will be

verified through the compliance and enforcement activities and strategies listed below.

The Tribe, through nearly 15 years of successful administration of CAA programs for major

sources and a highly developed and experienced compliance and enforcement program, anticipates

that the Tribe’s voluntary administration and implementation of these listed CAA programs and

standards at minor sources on the Reservation will result in significantly increased compliance and

reduced emissions. Central to this assessment is the Tribe’s proposal for increased compliance

oversight of the approximately 250 true minor oil and gas sources and six synthetic minor oil and

gas sources on the Reservation. Under the Tribe’s proposal, true minor sources would be inspected

on a five-year basis and synthetic minor sources on a two-year basis, through an EPA-approved

CMS. Under the current EPA administration of the TMNSR program and FIP, true minor sources

are not inspected, and synthetic minor sources are inspected every five years. The Tribe’s proposed

monitoring frequency is consistent with the CMS inspection frequency of the State of Colorado

and New Mexico air quality jurisdictions adjacent to the Reservation.

In addition to inspecting known oil and gas minor sources, the Tribe plans to investigate sources

identified in the Tribe’s emissions inventory that may be operating above TMNSR, FIP, or Title

V operating permit program emission thresholds without a federal or Tribal permit. The Tribe will

work to get these sources into compliance through the Tribe’s existing CAA authorities under 40

CFR Part 70, and CAA §§§§111, 112, 113 and 114, and, once delegated, through the TMNSR and

FIP authorities of 40 CFR Part 49.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

The Tribe anticipates that GHG emissions from minor oil and gas sources on the Reservation could

be reduced by approximately 29% each year through the Tribe’s priority measure of voluntary

administration and implementation of CAA programs and standards and realized through

implementation of an EPA-approved CMS. This estimation is based on a CARB report titled

“CARB’s Oil and Gas Methane Regulation 2018 Annual LDAR Summary”, which found that leak

detection and repair (LDAR) inspections reduced GHG emissions from leaking components and

valves by 29% (see Section 4.3) The CARB report is included as Appendix B. Table 1 provides a

more detailed list of these project components.

Table 1: Components of the Tribe’s Priority Measure for Reducing GHG Emissions

Components of the Tribe's Priority Measure for Reducing GHG Emissions

Component

Summary

• TMNSR is a preconstruction permit program that serves two purposes.

The first is to ensure that air quality is not significantly degraded by the

addition or modification of new sources. The second assures people that

any large new or modified industrial source in their neighborhoods will

Tribal Minor New

be as clean as possible, and that advances in pollution control occur

Source Review

(TMNSR)

concurrently with industrial expansion.

• Tribe has outlined a delegation agreement between EPA and the Tribe to

voluntarily obtain authority of the TMNSR program. Delegation is

anticipated to be finalized by the end of CY 2024.

• FIP is an air quality plan developed by EPA under certain circumstances

to help states or tribes attain and/or maintain the NAAQS for criteria air

pollutants and fulfill other requirements of the CAA.

• New or modified true minor new source review oil and gas sources in

Indian Country may obtain coverage to construct under the FIP, codified

Federal Implementation

at 40 CFR 49.

Plan (FIP)

• The FIP incorporates by reference several NSPS and MACT rules,

including NSPS OOOO.

• The Tribe has outlined a delegation agreement between EPA and the

Tribe to voluntarily obtain authority of the FIP program.

• Delegation is anticipated to be finalized by the end of CY 2024.

New Source

• The NSPS OOOO series rules, include OOOO, OOOOa and OOOOb,

Performance Standards

established emissions standards for GHG and VOC in the oil and gas

(NSPS) Subpart OOOO

sectors. These include standards for leaking components and LDAR

– Subpart OOOO –

programs. The Tribe has existing CAA authority to implement the

Standards of Performance

OOOO & OOOOa standards and plans to adopt OOOOb in the fall of

for Crude Oil and Natural

2024.

Gas Facilities

• An air quality plan developed by a tribe to help attain and/or maintain

NAAQS for CAPs and fulfill other requirements of the CAA.

• Unlike states, tribes are not required to adopt an implementation plan.

Tribal Implementation

• EPA established Emissions Guidelines under section 111(d) of the CAA

Plan (TIP)

for GHGs emissions (in the form of methane limitations) from existing

sources (designated facilities) under the new NSPS OOOOc rule.

• The Tribe is proposing to develop a TIP for adopting the Emissions

Guidelines established in the NSPS OOOOc rule.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

To increase tribal sovereignty and expand upon the Tribe’s current authority to implement the

NSPS, the Tribe will propose a rulemaking through the Commission to adopt NSPS Subpart

OOOOb into the Reservation Air Code (RAC) in late 2024 or early 2025.

The development of a TIP for adopting the Emissions Guidelines in NSPS Subpart OOOOc

continues the Tribe’s mission to improve air quality on the Reservation while also maintaining

national air quality standards outlined in NAAQS. Although the development of a TIP is not

required, the Tribe plans to develop and implement a TIP to increase tribal sovereignty and

advance the Tribe and Commission’s goals of having authority of all core CAA programs on the

Reservation.

Table 2 is a summary of the Tribe's priority measure, voluntary implementation of CAA programs

and standards. This includes TMNSR and FIP Implementation, NSPS Adoption, and TIP

development.

Table 2. TMNSR and FIP Implementation, NSPS Adoption, and TIP Development Summary

TMNSR and FIP Implementation, NSPS Adoption, and TIP Development Summary

Implementing

Southern Ute Indian Tribe Air Quality Division

agency

Geographic

Oil and gas sources within the boundary of the Reservation

location

Applicable sector

Oil and gas (industrial)

Funding sources

CPRG Implementation Grant

The Tribe will evaluate emissions reduction from the proposed measure in their

Metrics tracking

tri-annual emissions inventories. The next emissions inventory is for CY 2023

and will be complete in 2025.

Cost estimate

To be determined

Annual estimated

GHG and criteria

air pollutant

654.3 metric tons of GHG, 1.8 metric tons of VOC

emission

reductions

Implementation

Delegation of TMNSR and FIP. Adoption of NSPS OOOOb under the Tribe’s

authority

automatic NSPS delegation authority. Development of a TIP to adopt the

milestones

Emissions Guidelines of NSPS OOOOc.

The Tribe anticipates the delegation of the TMNSR and FIP by the end of CY

2024. The new NSPS OOOOb & OOOOc rules were published in the Federal

Implementation

schedule

in late 2024 or early 2025. AQD plans to submit a draft TIP to adopt the

Emissions Guidelines of NSPS OOOOc to EPA for approval in 2026.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

4.2.1 Other GHG Emission Reduction Measures Administered by AQD

Greenhouse gas emissions and other pollution reduction measures have been an ongoing goal of

the Tribe. The Tribe has received voluntary delegation of multiple CAA programs and air quality

regulations from the EPA, which can be viewed in detail in the RAC (Appendix C). A detailed

summary of current and future emission reduction measures is included in Table 3 below.

Table 3. Summary of AQD GHG Reduction Measures

GHG

Reduction

Measure

Air

Monitoring

Title V

Operating

Permit

Program

Summary

The Tribe operates three State and Local Air Monitoring Stations to monitor air

quality on the Reservation. Ambient air monitoring data collected from these stations

are reported to the EPA Air Quality System for NAAQS determinations and EPA’s

AirNow website for generating real-time health risk forecasting. To enable Tribal

members and the public with access to this information, the Tribe maintains a website

with real-time ambient pollutant concentrations and the corresponding EPA AirNow

index values. The AirNow index values are a color-based rating system to help people

understand when air quality can be harmful to their health.

On March 2, 2012, the EPA issued a final rule approving the Tribe’s Title V Program

application. This granted the Tribe full authority to implement and administer its 40

CFR Part 70 Operating Permit Program for Title V sources within the exterior

boundaries of the Reservation. The Tribe currently has Title V permits issued to 35

sources, which comprises approximately 14% of all Title V sources in the State of

Colorado within less than 1% of the State land base. The Tribe conducts bi-annual

compliance inspections based on an EPA-approved CMS and initiates civil

enforcement actions for non-compliance with permit terms and conditions. The

Southern Ute Indian Tribe is currently the only Tribe with a fully delegated Part 70

operating permit program.

Title V operating permits are legally enforceable documents issued to major stationary

sources after a source has begun operation. Operating permits include all federal, state

or tribal air pollution regulatory requirements that apply to the source. The program

does not allow for the addition of new emissions control requirements, but rather

clarifies the air pollution control obligations of major sources by compiling in one

document all of a source’s compliance requirements. The intent is that by including all

applicable requirements in one permit, it will be easier for the source owner, the

regulatory agency, and the public to determine if the source is in compliance. The

permits may contain, at the discretion of the permitting agency, additional monitoring,

recordkeeping, and reporting requirements designed to ensure that the source

maintains compliance with existing applicable requirements of the permit. Owners of

sources with operating permits must certify that the source is in compliance each year

and the permits must be renewed every five years. Each issued operating permit is

subject to public comment and offers the public an opportunity for a hearing.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

GHG

Reduction

Measure

NSPS &

NESHAP

Emission

Inventory

Development

Summary

On September 6, 2013, the EPA issued a final rule delegating authority to the Tribe to

implement and enforce CAA Section 111 (NSPS) and CAA Section 112 (NESHAP).

NSPS and NESHAP set the minimum standards for certain new, modified, and

existing sources of air pollution. The EPA delegation provided the Tribe with full

upfront approval to voluntarily implement and enforce any NESHAP that the

Commission chooses to include by reference at Article II, Part 3 of the RAC. EPA also

delegated voluntary authority for the Tribe to implement and enforce certain NSPS

that were incorporated by reference into Article II, Part 2 of the RAC by the

Commission. Although it’s unnecessary for the Tribe to have delegation of the NSPS

and NESHAP standards for the purposes of implementing and enforcing these

standards as applicable requirements of Title V permits, the delegation of these rules

provides the Tribe with the authority to enforce the standards independently of a Title

V permit. The Tribe and Commission plan to consider the incorporation of any new

NSPS and NESHAP that apply to Reservation sources into the RAC.

The Tribe plans to continue development of emissions inventories for the Reservation

to aid in future air quality planning and program development for maintaining

compliance with the NAAQS. Comprehensive emission inventories will be completed

no less than every three years and emission inventories of Title V sources will be

completed annually. At the request of EPA, the Tribe is developing a QAPP for

emission inventories which outlines the procedures followed by the Tribe during

development of emission inventories. The procedures outlined in the QAPP will

describe how the Tribe’s emission inventory development adheres to the guidelines

set forth in EPA’s Emission Inventory Improvement Program.

In addition to the above-described GHG reduction measures, the Commission’s Long Term Plan

describes several additional measures which the Tribe and Commission may consider

implementing in the future. These include: (1) a pollutant-specific voluntary program such as the

EPA’s Ozone Advance or Methane Challenge or a TIP (programs to reduce VOC and methane

emissions), (2) consideration of adopting certain State of Colorado air quality initiatives for the oil

and gas industry or other industries, (3) a Prevention of Significant Deterioration program, (4) the

designation of the Reservation as its own air quality control region, and/or (5) any program or rule

deemed beneficial for the health of the Reservation’s residents or its environment (such as a visible

emissions rule or GHG initiatives). These and other programs may be included in the CCAP.

4.2.2 Other GHG Emission Reduction Measures Occurring on the Reservation

Several Tribal-owned business entities and departments, including Red Willow, Red Cedar, and

DOE, and other private business entities on the Reservation, are engaged in other GHG emissions

quantification efforts and potential GHG emission reduction projects and the Tribe will continue

to engage these entities. The Tribe plans to include the power generation and potential GHG

emission reductions from these projects in the GHG emissions inventory and CCAP evaluation

and to integrate the data generated from Tribal business entity emission quantification efforts into

the CCAP. Table 4, below, is a summary of some of these GHG emissions reductions projects.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Table 4. Summary of Other GHG Emission Reduction Projects.

Enterprise

Red Willow

Production

Company

Red Willow

Production

Company

Red Willow

Production

Company

Red Willow

Production

Company

Red Willow

Production

Company

Red Willow

Production

Company /

Red Cedar

Gathering

Company /

DOE

Red Willow

Project

Estimated Project

Cost

Start

Admin Vehicle Electric Vehicle (EV) Pilot - TBD

TBD

Pilot program to evaluate use of EVs for

non-critical vehicle fleet (admin,

engineering, wells team, etc).

Solar installations on office building roofs - TBD

TBD

Install solar power systems on Red Willow

building roof. Look at other options in field

to offset emissions on larger industrial

buildings (new materials warehouse).

Routine aerial methane detection surveys $400,000/ ASAP

Drone or Fixed wing. Working to establish

year

methodology and frequency. Detect and fix

leaks before they emit for extended duration

and monitor progress on methane emission

reduction programs

Pneumatic Retrofit Program - Eliminate up

$3.5-5MM ASAP

to 80% of methane emissions associated

with gas driven pneumatic devices on

natural gas well pads and associated

facilities on Red Willow-operated assets on

the Reservation.

Continuous Monitoring Installations - Install $100,000/

TBD

new devices to monitor methane (and other) year

emissions continuously. Allow for

notifications to operators when leaks are

detected and measure actual emissions for

reporting to regulatory agencies.

Wellsite Electrification Program - Outside

$10MM+ Grid study

engineering firm to conduct grid study to

planned for

compare existing power infrastructure to gas

2024,

production and transportation facilities to

installation

determine approach towards grid

2025

improvements. Engineering firm will

develop priority areas based on proximity,

cost, reduced emissions, and wellsite/facility

profitability (lifespan of operation).

Reduction in CH4, CO2, N2O, PM2.5, PM10

and VOC emissions.

Emissions Tracking Database - Specialized $100,000/ ASAP

software for tracking emissions and results

year

of reduction programs.

Project

Completion

TBD

ongoing

5-7 years

TBD

10 years

ongoing

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Enterprise

DOE

Project

Estimated Project

Cost

Start

$5MM

ongoing

Enhanced Outcrop Methane Capture Project

- Project includes installation of two shallow

horizontal methane capture pilot wells with

the goal of reducing naturally occurring

methane seepage from the Fruitland Coal

outcrop by intercepting the methane in the

subsurface before it is emitted. The project

also includes pilot testing of Bridger

Photonics, Trellisense, and other advanced

methane detection technologies in the San

Juan Basin and statistical analysis of historic

methane seepage data to guide future seep

mitigation efforts and reduce methane

seepage to the atmosphere.

Grid Resiliency Grant - The DOE was

$340,000

awarded a grant to improve grid resiliency

and decrease power outages on the

Reservation. This grant is a partnership with

La Plata Electric Association. Grid

resiliency projects reduce power outages at

industrial facilities and require fewer well

interventions and work overs which require

venting methane to the atmosphere thereby

reducing methane emission. The Tribe

expects to receive an additional $750,000 in

formula grant funding over the next three

fiscal years as part of the program and is

looking into additional electrification of

oilfield equipment to reduce methane

emissions.

Orphaned Well Program Grant - The DOE

$500,000

was awarded a grant through the Department

of the Interior to investigate wells plugged

and abandoned on the Reservation prior to

the year 2000. The work is aimed at a

desktop and field review of these sites and

the goal is to ensure tribal minerals are

protected and are not leaking to the

atmosphere. This is the first phase of the

work and subsequent phases will focus on

plugging any wells which are found to be

leaking methane to the atmosphere.

Project

Completion

12/1/2025

ongoing

1/1/2027

2/1/2024

2/1/2027

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Enterprise

Project

DOE

Estimated Project

Cost

Start

~$100,000 ongoing

/year

Project

Completion

TBD

Orphaned Well Plugging - The Tribe is

actively managing plugging and

abandonment of two orphaned wells on the

Reservation. Plugging of the wells may

reduce fugitive methane emissions.

Growth

Arkansas Loop/Simpson Treating Plant CO2 TBD

TBD

Fund

Sequestration Project - Plan to capture

250,000 metric tons of CO2 from the

existing Arkansas Loop/Simpson natural gas

treating plant to be routed to a pipeline for

subsequent geologic sequestration via

subsurface injection.

Growth

Coyote Clean Power Project - The capture

TBD

Fund

of CO2 from a 250 MW natural gas-fired

powerplant that is currently under

construction. The CO2 will be routed

through a pipeline for subsequent geologic

sequestration via subsurface injection.

Growth

Lidar Flyover of the Reservation TBD

TBD

Fund

Undertaken by the Growth Fund under the

IRA MERP grant and private funding to

quantify methane emissions on the

Reservation.

Primergy

Solar Energy Project - The planning phase

TBD

Energy

of a project for a 1,920-acre, 155 MW solar

energy project on the Reservation.

Notes: ASAP – as soon as possible; MM – millions; MW – megawatt; Lidar – Light Detection and

Ranging; MERP – Methane Emissions Reduction Program; TBD – to be determined

4.3 GHG Emissions Projections and Reduction Targets

For the purposes of the PCAP, the Tribe has established GHG emissions projections and reductions

from leaking components at minor oil and gas sources, on a per-site basis, and forecasted the

anticipated reduction through five years of inspections under the Tribe’s proposed five-year EPA

approved minor source CMS. The Tribe has also provided emissions projections and reductions

through 2050.

The Tribe has developed an emissions reductions quantification method utilizing (1) leaking

component and fugitive emissions data from the Tribe’s 2020 EI, (2) minor source data for

Reservation sources, and (3) a report developed by CARB titled “CARB’s Oil and Gas Methane

Regulation 2018 Annual LDAR Summary”. The CARB report summarized emission reductions

from leaking component identification and subsequent corrections.

Emissions Projections:

To establish emission projections, the Tribe first determined the GHG emissions contributions

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

from leaking components, fugitive emissions and pneumatic devices at true minor oil and gas

sources on the Reservation for the baseline year of CY 2020, using data from the Tribe’s 2020 EI.

The Tribe used these data to project GHG emissions forward from base year 2020 by determining

a per source GHG emissions estimate and an estimated minor oil and gas source growth rate.

Based on the CY 2020 EI, the Tribe has estimated that one true minor source has a PTE of 520.67

CO2e metric tons per year. The Tribe established an estimated true minor source growth rate by

downloading the current FIP registration data from the EPA Region 8 and determining a per year

average for new true minor sources based on source registrations from 2016 through the beginning

of 2024. By averaging the number of sources registered between 2016 and 2024, the Tribe

determined an estimated true minor source growth rate of 4.3 new sources per year. To project

emissions forward from the currently known number of true minor sources on the Reservation for

2023 (254 sources), the Tribe applied the 4.3 sources per years growth rate and multiplied it by

the per source estimated GHG emissions of 520.6 metric tons of CO2e per year.

Using this methodology, the Tribe estimated that, without voluntary implementation of CAA

programs and standards, GHG emissions from leaking components, fugitive emissions and

pneumatic devices will increase by 654.6 metric tons of CO2e per year. Projecting this per year

emissions increase forward for a five-year period would yield an increase of 3,271.5 metric tons

of CO2e. Total estimated emissions from leaking components, fugitive emissions and pneumatic

devices for year 2025 are 136,590.4 metric tons of CO2e and 147,871.7 metric tons for year 2030.

Reduction Targets:

To establish a GHG emissions reduction target, the Tribe applied the 29% GHG emissions

reduction observed in the 2018 CARB report to each projected year, from 2025 through 2050. The

CARB report determined that leak detection and repair inspections resulted in a 29% reduction in

fugitive gas emissions from leaking components.

During the first five years, through the Tribe’s voluntary administration and implementation of

CAA programs and standards and corresponding compliance inspections at all regulated sources,

the Tribe expects to see approximately 39,611.2 metric tons of GHG emissions.

As of April 1, 2024, there were 258 true minor sources registered under the FIP and six synthetic

minor sources permitted through the TMNSR program on the Reservation. For the purposes of

emissions projection and estimated reductions, the Tribe has assumed synthetic minor sources to

have the same per site emissions and emissions reduction potential as true minor sources. In

actuality, synthetic minor sources are larger sources and are likely to have higher emissions rates

and higher corresponding emission reductions.

Table 5 is a summary of the number of estimated sources (true minor and synthetic minor),

emissions projections that would occur without voluntary implementation of CAA programs and

standards, and emissions reduction targets based on the assumptions and calculations presented

above.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Table 5. Emissions Projections and Reductions Targets.

GHG Emissions Projection by

GHG Emission Reduction

Year (tpy CO2e)

Target (tpy CO2e)

2020 238

123,920.7

2021 243

126,524.0

2022 250

130,168.8

2023 254

132,251.5

2024 258*

134,334.2

2025 262.3

136,590.4

39,611.2

2026 266.7

138,846.7

40,265.5

2027 271.0

141,102.9

40,919.8

2028 275.3

143,359.2

41,574.2

2029 279.7

145,615.4

42,228.5

2030 284.0

147,871.7

42,882.8

2031 288.3

150,128.0

43,537.1

2032 292.7

152,384.2

44,191.4

2033 297.0

154,640.5

44,845.7

2034 301.3

156,896.7

45,500.1

2035 305.7

159,153.0

46,154.4

2036 310.0

161,409.3

46,808.7

2037 314.3

163,665.5

47,463.0

2038 318.7

165,921.8

48,117.3

2039 323.0

168,178.0

48,771.6

2040 327.3

170,434.3

49,425.9

2041 331.7

172,690.5

50,080.3

2042 336.0

174,946.8

50,734.6

2043 340.3

177,203.1

51,388.9

2045 344.7

179,459.3

52,043.2

2046 349.0

181,715.6

52,697.5

2047 353.3

183,971.8

53,351.8

2048 357.7

186,228.1

54,006.1

2049 362.0

188,484.4

54,660.5

2050 366.3

190,740.6

55,314.8

Total Emissions Reductions 2025-2050

1,186,574.9

Notes: number of sources are based on EPA permitting data from 2016-2024 and projected for 20242050; tpy – tons per year; “-” – indicates no data; * - 2024 sources based on sources as of April 1, 2024.

Year

Number of Sources

Refined projections and reductions targets may be included in the CCAP.

4.4 Benefits Analysis

The AQD, Commission, State of Colorado, and Tribe believe that the Tribe’s administration of

the TMNSR program and FIP, would result in increased compliance with CAA permit programs

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

and standards on the Reservation through increased source oversight by the of the Tribe and

application of the Tribe’s established CAA compliance and enforcement sections. To date, true

minor sources on the Reservation have never been inspected by the EPA and synthetic minor

sources are only inspected by the EPA every five years. Additionally, based on emissions

information submitted to the Tribe as part of the 2020 EI development, it’s likely that a number of

sources on the Reservation are operating without applicable CAA permits and may be out of

compliance with other CAA standards. Because EPA does not currently perform on-site

inspections of the known minor sources on the Reservation or investigate potentially applicable

sources on the Reservation, the Tribe intends to perform the work of the EPA in administering

these responsibilities, voluntarily. The Tribe plans to inspect the known true minor sources on a

five-year basis and synthetic minor sources on a two-year basis, through an EPA-approved CMS.

The Tribe will work to bring all sources into compliance using the Tribe’s authority to implement

CAA programs.

The Tribe has a proven record of improving compliance with the CAA on the Reservation, through

its voluntary implementation of the Title V operating permit program. When the Tribe began

performing Title V source inspections in 2015 under its voluntary 2012 delegation of the Title V

operating permit program, non-compliance with CAA rules was prevalent. As displayed in Figure

3, below, compliance has significantly improved since that time, as can be determined through

examining the downward trend of formal enforcement actions being initiated by the Tribe from

2015 through 2023. In general, formal enforcement actions include more significant instances of

CAA non-compliance, including types on non-compliance that are more likely to have caused, or

have the potential to cause, environmental harm. Informal enforcement actions are generally for

smaller occurrences of CAA non-compliance that are unlikely to have caused environmental harm,

such as minor recordkeeping or reporting deviations.

Figure 3. CAA Enforcement at Title V Sources by Calendar Year

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Many of the formal enforcement actions initiated by the Tribe involved similar instances of noncompliance at multiple sources owned by the same owner/operator and resulted in significant

penalties under the Tribe’s Enforcement Procedures and Penalty Policy. Based on the results of

the Tribe’s Title V inspections, it’s expected that increased compliance oversight will have a

similar effect on true minor sources and synthetic minor sources on the Reservation and result in

greater CAA compliance and a reduction in GHG emissions.

It is expected that the Tribe’s GHG reduction plan would have a corresponding reduction of copollutants entrained in the natural gas stream. Co-pollutants would include VOCs, CAPs, and

Haps. The reduction of VOC, an ozone precursor, could also have the co-benefit of reducing

ground level ozone formation. Emission reductions will be quantified consistently with the

emission factors used in the 2020 EI, or corrected to more accurate emission factors, if available.

Table 6 shows the 2020 criteria pollutants and HAP emissions from true minor oil and gas sources

as calculated in the 2020 EI.

Table 6: 2020 Criteria Pollutant and HAP Emissions from True Minor Sources (tons)

Pollutant

Emissions

NOx

4,575.2

3,248.1

VOC

834.5

42.8

SO2

16.1

Total HAP

291.0

GHG (CO2e)

1,568,843.6

The Tribe's proposed GHG reduction measure will reduce CAPs and other HAPs in addition to

GHG emissions. An estimation of these reductions was developed for VOCs and projected

estimates and the correlating reduction targets are included in Table 7 below.

Table 7. VOC Estimated Projections and Reductions

Year

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029

2030

2031

2032

2033

2034

2035

VOC Emissions Projection by

Year (tpy)

330.8

337.8

347.5

353.1

358.6

364.6

370.7

376.7

382.7

388.7

394.8

400.8

406.8

412.8

418.9

424.9

VOC Emission Reduction Target

(tpy)

105.7

107.5

109.2

111.0

112.7

114.5

116.2

118.0

119.7

121.5

123.2

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Year

VOC Emissions Projection by

Year (tpy)

430.9

436.9

442.9

449.0

455.0

461.0

467.0

473.1

479.1

485.1

491.1

497.2

503.2

509.2

2036

2037

2038

2039

2040

2041

2042

2043

2045

2046

2047

2048

2049

2050

Total Emissions Reductions

2,278.2

2025-2030

Total Emissions Reductions

10,923.1

2025-2050

Notes: tpy – tons per year

VOC Emission Reduction Target

(tpy)

125.0

126.7

128.5

130.2

131.9

133.7

135.4

137.2

138.9

140.7

142.4

144.2

145.9

147.7

660.6

3,167.7

In addition to the Tribe’s primary PCAP goal of reducing GHG emissions relating to the repair of

leaking fugitive emission sources, the AQD also anticipates that increased compliance oversight

of minor sources by the Tribe will result in secondary co-pollutant emission reductions of CAPs

from internal combustion engines, glycol dehydration units, and other oil and gas production

equipment. Co-pollutants would include NOx, CO, VOC, and HAPs. These emission reductions

would be realized through increased compliance with NSPS and MACT rules relating to these

types of oil and gas emission units.

4.5 Review of Authority to Implement

All lands located within the exterior boundaries of the Reservation are under the jurisdiction of the

Reservation Air Program established by the Intergovernmental Agreement between the Southern

Ute Indian Tribe and the State of Colorado Concerning Air Quality Control on the Southern Ute

Indian Reservation (Pub. L. No. 108-336, 118 Stat. 1354). The Intergovernmental Agreement is

managed by the Commission, which serves as the policy-making and administrative review

authority for the Reservation Air Program, and the AQD has been delegated the administration of

the Reservation Air Program.

In 2012, the EPA issued a final rule approving the Tribe’s Title V Program application, granting

the Tribe full authority to implement and administer its 40 CFR Part 70 Operating Permit Program

for Title V sources within the exterior boundaries of the Reservation. Additionally, on September

6, 2013, EPA issued a final rule delegating authority to the Tribe to implement and enforce CAA

§111 (NSPS) and CAA §112 (NESHAP and MACT).

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

The Tribe and EPA are currently finalizing a delegation agreement for administration of the federal

TMNSR Program and the FIP. The Tribe anticipates receiving the full authority to implement the

programs in 2024. Once delegation is received, the Tribe will have authority to issue permits and

conduct compliance inspections under the TMNSR program and FIP. Enforcement authority under

these programs is not delegable to Tribes and will remain with EPA; however, the Tribe has

independent authority to implement and enforce the NSPS, NESHAP and MACT standards, which

are incorporated by reference by the FIP, and which in many instances are the primary emissions

standards and limits that apply at minor oil and gas sources. Therefore, under these EPA

delegations, the Tribe will have substantial authority to implement the voluntary CAA programs

and standards being proposed by this PCAP.

Other GHG emissions reduction measures may be outside the authority of the Commission and

the Tribe to implement or would require Tribal Council approval. The Tribe may offer support to

projects outside their jurisdiction.

4.6 Identification of Other Funding Mechanisms

The Tribe has applied for and received partial funding for activities related to development and

administration of the TMNSR program and FIP under Fiscal Year (FY) 23 and FY24 CAA §105

grants, a small FY24 CAA IRA grant, an FY22 Multi-purpose Grant, an FY22 General Assistance

Program (GAP) grant, and FY21 and FY22 CAA §103 grants. In some of these funding examples,

no funding or only partial funding was provided to the Tribe.

The Tribe’s delegation request application was conditioned upon the Tribe receiving assurance

from EPA Region 8 of a continued funding source for year-to-year administration of the programs

by the Tribe. This request was to provide the Tribe with assurance that the programs could be

funded into the future and confidence that the Tribe’s efforts to build the resource and staffing

needs to successfully administer the program are preserved. The EPA has been unable to provide

the Tribe with funding assurance, and therefore, the Tribe has sought funding from multiple grant

opportunities to fund the development and future implementation of these programs. In FY23, it

was recommended by EPA Region 8 staff that the Tribe pursue funding under the CPRG as a

potential funding source to administer the TMNSR and FIP. In addition to the CPRG

implementation grant, the Tribe plans to continue concurrently applying for funding each fiscal

year under CAA §105 and GAP to ensure sufficient funding can be secured to administer the

programs.

4.7 Workforce Planning Analysis

For the purposes of the Phase II implementation grant, the Tribe anticipates the need for staff hours

from six full-time AQD positions, including, (1) the AQDH, (2) the Air Quality Technical

Manager (AQTM), (3) two AQ Planners, (4) the Senior Air Quality Compliance Specialist

(SAQCS), and (5) a Grants Coordinator (GC). The AQDH and AQTM would be responsible for

directing the broad scale planning, resource development, and meeting planning for the CCAP.

The AQ Planners would be responsible for the detailed plan development, GHG emission

inventory development, and meeting agenda development. The SAQCS would be responsible for

CCAP planning and resource development, specific to the AQD’s inspection and emission

reduction activities at TMNSR and FIP oil and gas sources. In addition, the SAQCS was a position

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

identified by the Tribe as necessary to fulfill the resource needs that would be assumed by the

Tribe under an administrative delegation of the TMNSR program and FIP for the purpose of

inspecting and documenting compliance and non-compliance at the six synthetic minor sources

and over 250 true minor sources. The GC would be responsible for on-going grant reporting,

development, and analysis for the CCAP.

The Tribe is dedicated to being a premier employer in the southwestern region of Colorado. The

Tribe offers competitive wages and a significant employee benefits package that includes paid

holidays, health insurance, annual and sick leave accrual, dental, vision, life insurance, and

retirement plans for full-time employees. This also includes training opportunities, technology,

workwear, and certifications, as needed, for individuals to perform job duties.

The EPA considers the Reservation and Tribal members an environmental justice population.

Creation of high-quality jobs in environmental justice populations is a high priority of the EPA

and the Tribe.

The Tribe follows the requirements of the Davis-Bacon and Related Acts for hiring contractors

and subcontractors for performing on federally funded and assisted contracts that exceed $2,000

for public works projects.

The Tribe understands that the need for sustainability, innovation, and efficient strategies to reduce

GHG is an on-going effort that will result in new training opportunities, expansion of current

environmental departments, and on-going education efforts for current and future employees. The

Tribe will continue to seek new training and work closely with both state and federal entities to

ensure employees are receiving the latest available training and educational opportunities to

enhance workforce development.

5 Next Steps

The results of the survey outlined in Section 3.3 will inform sections of the CCAP and future GHG

reduction projects on the Reservation.

Oil and gas production is the single-largest emitter of GHG on the Reservation and thus remains

the Tribe’s priority sector. Other sectors that will be included in the analysis in the CCAP include

mobile combustion, electricity consumption, urban forestry, agriculture, waste generation,

wastewater treatment, and water sectors. The Tribe will determine what source sectors are viable

for potential GHG emission reductions, including sectors where the Tribe has authority to

implement the measures, and those where the Tribe does not. Certain CCAP milestones and target

completion dates will be based off the scheduled completion and implementation dates of projects

being conducted by entities outside of the Tribe, including the oil and gas industry and other private

industry, such as solar installation companies.

Southern Ute Indian Tribe Priority Climate Action Plan

April 2024

Appendix A: 2020 EI

__________________________________________________________________

Final Report for 2020 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

Emission Inventory report prepared by Matt Wampler, Air Quality Technical Manager

January 2023

Table of Contents

List of Figures ................................................................................................................................. 2

List of Tables .................................................................................................................................. 3

List of Acronyms ............................................................................................................................ 5

Executive Summary ............................................................................................................. 7

II.

Overview .............................................................................................................................. 8

Purpose of Inventory .................................................................................................... 8

Geographic Location of Southern Ute Indian Reservation .......................................... 8

Climate.......................................................................................................................... 9

Geology ........................................................................................................................ 9

Sources........................................................................................................................ 10

III.

Data Quality Objectives ..................................................................................................... 11

Accuracy ..................................................................................................................... 11

Uncertainty ................................................................................................................. 11

Completeness .............................................................................................................. 11

Comparability ............................................................................................................. 11

IV.

Point Sources ..................................................................................................................... 12

Title V Permitted Oil and Gas Sources ...................................................................... 12

Minor Oil and Gas Point Sources ............................................................................... 14

Permitted Point Sources.............................................................................................. 22

Landfill Gas ................................................................................................................ 22

Airports ....................................................................................................................... 25

Non-Point Sources ............................................................................................................. 27

Small Oil and Gas Sources ......................................................................................... 27

Fruitland Formation Outcrop Natural Gas Seeps ....................................................... 62

Gas Stations ................................................................................................................ 63

Aviation Gasoline ....................................................................................................... 64

Gravel Pits .................................................................................................................. 65

Residential Heating..................................................................................................... 66

Agricultural Burning................................................................................................... 71

VI.

Mobile Sources .................................................................................................................. 72

On-Road Mobile Sources ........................................................................................... 72

Non-Road Mobile Sources ......................................................................................... 73

VII.

Events ................................................................................................................................. 74

Wildland Fires and Prescribed Burns ......................................................................... 74

VIII. Biogenic ............................................................................................................................. 76

IX.

Summary ............................................................................................................................ 77

Bibliography ...................................................................................................................... 86

XI.

Appendix – Quality Assurance Review ............................................................................. 89

List of Figures

Figure 1: Southern Ute Indian Reservation total criteria pollutant emissions [tons] .....................................................8

Figure 2: Southern Ute Indian Reservation total criteria pollutant emissions [tons] .....................................................9

Figure 3: Criteria pollutant and HAP emissions at Title V sources [tons] .....................................................................13

Figure 4: NOx and CO emissions from Title V sources by equipment type [tons] ........................................................13

Figure 5: VOC and HAP emissions from Title V sources by equipment type [tons] ......................................................14

Figure 5: Title V speciated HAP emissions [tons] .........................................................................................................14

Figure 6: Criteria pollutant and HAP emissions from synthetic minor sources [tons] ..................................................16

Figure 7: NOx and CO emissions from synthetic minor sources by equipment type [tons] .........................................17

Figure 8: VOC and HAP emissions from synthetic minor sources by equipment type [tons] .......................................17

Figure 9: Speciated HAP emissions from synthetic minor sources [tons].....................................................................18

Figure 10: Criteria pollutant and HAP emissions from true minor oil and gas sources [tons] .....................................20

Figure 11: NOx and CO emissions from true minor oil and gas sources by equipment type [tons] .............................20

Figure 12: VOC and HAP emissions from true minor oil and gas sources by equipment type [tons] ...........................21

Figure 13: GHG emissions from true minor oil and gas sources by equipment type [tonnes] .....................................21

Figure 14: Municipal solid waste landfill emissions [tons]...........................................................................................24

Figure 15: CO and NOx emissions from airports [tons] ................................................................................................ 26

Figure 16: VOC and Total HAP emissions from airports [tons] ....................................................................................26

Figure 17: Criteria pollutant and HAP emissions from small oil and gas sources [tons] ..............................................29

Figure 18: NOx and CO emissions from small oil and gas sources by equipment type [tons]......................................29

Figure 19: VOC and HAP emissions from small oil and gas sources by equipment type [tons] ...................................29

Figure 20: GHG emissions from small oil and gas sources by equipment type [tonnes]..............................................30

Figure 21: Speciated HAP emissions from small oil and gas sources [tons].................................................................31

Figure 22: Engine counts by engine configuration and horsepower at small oil and gas sources ...............................31

Figure 23: CO and NOx emission from small oil and gas sources by engine type [tons]..............................................34

Figure 24: VOC and Total HAP emissions from small oil and gas sources by engine type [tons] .................................34

Figure 25: Liquid storage tanks at small oil and gas sources by tank contents ........................................................... 42

Figure 26: VOC and HAP emissions from liquid storage tanks at small oil and gas sources [tons] ............................. 51

Figure 27: VOC and HAP emissions from Fugitives, Blowdowns, Recompletions, and Pneumatics [tons] .................. 60

Figure 28: GHG emissions from Fugitives, Blowdowns, Recompletions, and Pneumatics [tonnes] .............................61

Figure 29: Average equipment counts at small oil and gas sources by equipment type .............................................61

Figure 30: NOx and CO emissions by source category [tons] .......................................................................................80

Figure 31: VOC and HAP emissions by source category [tons] * ................................................................................... 80

Figure 32: NOx and CO emissions from oil and gas sources [tons] ..............................................................................81

Figure 33: VOC and HAP emissions from oil and gas sources [tons] ............................................................................ 82

Figure 34: GHG (CO2e) emissions from oil and gas sources [tonnes] ...........................................................................82

Figure 35: Comparison of NOx, CO, and VOC emissions from the 2015 SUIT EI, 2017 SUIT EI, and the 2017 SUIT EI

[tons] 83

Figure 36: Comparison of oil and gas NOx, CO, and VOC emission estimations for the Southern Ute Indian

Reservation from the 2015, 2017, and 2020 SUIT EIs [tons]........................................................................................84

List of Tables

Table 1: Title V criteria pollutant, HAP, and GHG emissions estimations [tons] * ........................................................13

Table 2: Title V HAP emissions [tons] ...........................................................................................................................14

Table 3: 40 CFR Part 49 Minor New Source Review Program Emissions Thresholds ...................................................15

Table 4: Criteria Pollutant, HAP, and GHG emissions for synthetic minor sources [tons]* .......................................... 16

Table 5: Speciated HAP emissions from synthetic minor sources [tons] ......................................................................18

Table 6: Criteria pollutant and HAP emissions from true minor sources [tons] *..........................................................20

Table 7: Criteria pollutant and HAP emissions from permitted non-oil and gas point sources [tons] .........................22

Table 8: Municipal solid waste landfill refuse in place [tons] and emissions [tons] * ...................................................24

Table 9: Criteria pollutant and HAP emission from airports [tons]* ............................................................................26

Table 10: Emissions from small oil and gas sources [tons] * .........................................................................................28

Table 11: Speciated HAP emissions from small oil and gas sources [tons] ..................................................................30

Table 12: Natural gas-fired reciprocating internal combustion engine counts and criteria pollutant, HAP, and GHG

emissions for small oil and gas sources [tons]*............................................................................................................33

Table 13: Turbine count and criteria pollutant, HAP, and GHG emissions at small oil and gas sources [tons] * ..........36

Table 14: Theoretical extended natural gas analysis – average of 31 natural gas analyses from the Southern Ute

Indian Reservation .......................................................................................................................................................38

Table 15: GRI-GLYCalc Model input parameters for TEG Dehydration units at small oil and gas sources ..................39

Table 16: GRI-GLYCalc Model emissions output for TEG Dehydration units [tons] ......................................................40

Table 17: VOC and HAP Emissions from TEG Dehydration Units from small oil and gas sources [tons] .....................41

Table 18: Assumed annual average liquid throughput values for produced water, oil, and condensate tanks at small

oil and gas sources* .....................................................................................................................................................43

Table 19: Produced water flash gas analysis from small oil and gas sources on the Southern Ute Indian Reservation

[Mol %]* .......................................................................................................................................................................46

Table 20: Condensate flash gas analysis from small oil and gas sources on the Southern Ute Indian Reservation [Mol

%]*

Table 21: Average gas to water and gas to condensate ratios for small oil and gas sources * ....................................48

Table 22: VOC, HAP, and GHG Emissions from liquid storage tanks at small oil and gas sources [tons] * ...................51

Table 23: Criteria pollutant, HAP, and GHG emissions from heaters and boilers at small oil and gas sources [tons] *53

Table 24: Assumed fugitive emission component counts at single and co-located natural gas well-sites ..................54

Table 25: Emissions of VOC, HAP, and GHG from equipment leaks and fugitive emission sources at small oil and gas

sources [tons]* .............................................................................................................................................................55

Table 26: VOC, HAP, and GHG emissions from natural gas driven pneumatic devices at small oil and gas sources

[tons]* 57

Table 27: Assumed values for annual natural gas compressor blowdown events occurring at small oil and gas

sources in 2017 ............................................................................................................................................................ 58

Table 28: VOC, HAP, and GHG emissions from natural gas blowdowns at small oil and gas sources [tons] * .............58

Table 29: Assumed values for well completion and recompletion activities at small oil and gas sources * .................59

Table 30: VOC, HAP, and GHG emissions from well recompletion activities at small oil and gas sources [tons] * .......60

Table 31: Average equipment counts at single and co-located well-sites at small oil and gas sources ......................61

Table 32: Emissions of methane, CO2, and total GHG in CO2 Equivalent [tonnes] .......................................................63

Table 33: Annual gasoline throughput at gasoline stations located on the Southern Ute Indian Reservation [gal/yr] *

Table 34: VOC emissions from gasoline dispensing stations [tons] .............................................................................64

Table 35: VOC and HAP emissions from aviation gasoline [tons] * ...............................................................................65

Table 36: Emissions of PM10 and PM2.5 from active gravel pits ...................................................................................66

Table 37: Fireplace and wood burning residential heating data .................................................................................67

Table 38: Criteria pollutant and GHG emissions from fireplaces and wood burning stoves [tons] * ............................68

Table 39: Liquid propane residential heating data ......................................................................................................69

Table 40: Criteria pollutant and GHG emissions from liquid propane gas heating at residential sources [tons] * .......70

Table 41: Natural gas residential heating data ...........................................................................................................70

Table 42: Criteria pollutant and GHG emissions from natural gas heating at residential sources [tons] * ..................71

Table 43: Criteria pollutant, NH3, and HAP emissions from agricultural burning [tons]* ............................................72

Table 44: Criteria pollutant emissions from on-road mobile sources [tons] ................................................................73

Table 45: Criteria pollutant emissions from non-road mobile sources [tons] ..............................................................74

Table 46: Forest fire occurrence by fuels characteristic classification system, fuel bed type, and acres burned.........75

Table 47: Criteria pollutant, NH3, and GHG emissions from prescribed burns and wildland fires [tons] * ...................76

Table 48: Criteria pollutant and HAP emissions from biogenic sources [tons] * ...........................................................77

Table 49: Criteria pollutant, HAP, and GHG emissions on the Southern Ute Indian Reservation [tons] *.....................79

Table 50: Emissions from oil and gas sector sources [tons] * .......................................................................................81

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

BTEX

Benzene, Toluene Ethyl-Benzene, Xylene

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

Carbon Monoxide

CO2e

Carbon Dioxide Equivalent

COGCC

Colorado Oil and Gas Conservation Commission

Calendar Year

CFR

Code of Federal Regulations

DRMS

Colorado Division of Reclamation Mining and Safety

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

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

Liquid Petroleum

LTO

Landing and Take-off Cycles

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

Ozone

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

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

WRAP

Western Regional Air Partnership

4SLB

Four stroke lean burn

4SRB

Four stroke rich burn

2SLB

Two stroke lean burn

Executive Summary

The Southern Ute Indian Tribe (Tribe) Air Quality Program (AQP) has prepared an emissions

inventory of quantifiable point and non-point sources on the Southern Ute Indian

Reservation (Reservation) for calendar year 2020 (CY2020). 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 from sources under the Tribal Minor New Source Review

(TMNSR) program (true minor sources), and a Clean Air Act (CAA) Section 114 information

collection request issued by the Tribe in June 2021. Data for other sources were collected

from various reputable state, local, and federal data sources.

This report also covers emissions from landfills, nonpoint sources, mobile sources, wildfires,

biogenic sources, and the Fruitland outcrop. Nonpoint sources include agricultural burning,

residential heating, gravel pits. gas stations, and airports.

Reservation emission totals for CY 2020 were 19,743.58 tons of oxides of Nitrogen (NOx),

8,773.01 tons of Volatile Organic Compounds (VOC), 80.94 tons of Sulfur Dioxide (SO 2),

396.57 tons of Particulate Matter 10 micrometers or less in diameter (PM 10), 146.02 tons of

Particulate Matter 2.5 micrometers or less in diameter (PM 2.5), 18,767.33 tons of Carbon

Monoxide (CO), 1,527.28 tons of total Hazardous Air Pollutants (HAP), and 11,342,510.62

metric tonnes of Greenhouse Gas (GHG) emissions measured in Carbon Dioxide Equivalent

(CO2e).

Total criteria pollutant (NOx, VOC, SO2, PM10, PM2.5, CO) and HAP emissions on the

Reservation for 2020 are presented below in Figure 1.

Figure 1: Southern Ute Indian Reservation total criteria pollutant emissions [tons]

Total Criteria Pollutant Emissions on the Southern

Ute Indian Reservation in CY 2020 (tons)

1,527.28

18,767.33

542.58

NOx

II.

19,743.58

8,773.01

80.94

VOC

SO2

HAP

Overview

1. Purpose of Inventory

The purpose of this Emissions Inventory (EI) was to establish baseline emissions estimates

for the 2020 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, PM 10, PM2.5, 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 (Figure 2). 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.

Figure 2: Southern Ute Indian Reservation total criteria pollutant emissions [tons]

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 average temperatures are between 20 and 40 degrees Fahrenheit.

Freezing temperatures are common throughout the winter and during the 2020 calendar

year the coldest month was February with a low of 3.4 degrees Fahrenheit and a monthly

average of 32.4 degrees Fahrenheit. During the summer months the average high

temperatures were in the high eighties and nineties. The warmest month of 2020 was July

with a high of 99.6 degrees Fahrenheit, and a monthly average of 73.6 degrees Fahrenheit.

Rain was the dominant form of precipitation on the Reservation and total precipitation for

calendar year 2020 was 4.0 inches. The driest month was June with 0.3 inches of

precipitation and the wettest month was August with 2.2 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 of the

Southern Ute Indian Tribe: Ambient Monitoring. (2020). 2020 AQS Ute 3 Humidity and Temperature Hourly Data.

Retrieved from: http://www.southernute-nsn.gov/environmental-programs/air-quality/ambient-monitoring/.

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 2020.

5. Sources

The sources included in this emissions inventory were organized according to source type

and size. These 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,

b. Registered minor TMNSR sources,

3) Municipal solid waste landfills, and

4) Airports.

B. Non-point Sources

1) Small oil and gas sources,

2) Fruitland Formation Outcrop natural gas seeps,

3) Gasoline stations,

4) Aviation gasoline dispensing,

5) Gravel pits,

6) Residential heating, and

7) Agricultural burning.

C. Mobile Sources

1) On-road vehicles, and

2) Non-road equipment.

D. Events

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.

1) Fire events (wildland fires and prescribed burns).

E. Biogenic Sources

III.

Data Quality Objectives

Data objectives for this inventory are as follows:

1. Accuracy



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.

Emission calculation models were utilized when available (GRI-GLYCalc 4.0, Tanks 4.09d,

etc.) and all inputs are provided in annual emission reports or 2020 CAA Section 114

Information Collection Request (ICR) worksheets.

Results of the 2020 SUIT EI were compared with results from the 2017 SUIT EI.

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.

Emissions differences between CY2020 SUIT EI, CY2017 SUIT EI, and CY2015 SUIT EI may

occur due to different preparation methodologies and assumptions.

3. Completeness



Capture 100% of point source emissions reported in the annual emission fees for CY2020.

Capture 95% of non-point oil and gas sources in the 2020 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 2017 SUIT EI and 2015 SUIT EI.

Emission factors and assumptions will be compared with methodologies used in similar

emission calculation applications.

Point Sources

As of 2020, there were a total of 2,860 oil and gas production sources operating on the

Reservation. These sources consisted of 35 sources operating under Title V operating

permits, 11 sources operating under TMNSR permits (synthetic minor sources), 238 true

minor sources, and 2,582 non-point sources with emissions below the TMNSR program

thresholds, referred to in this emissions inventory as “small oil and gas sources”.

1. Title V Permitted Oil and Gas Sources

Description of Sources

Thirty-five oil and gas Title V sources operated on the Reservation during calendar year 2020.

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) 100 tons per year (tpy)

of a single criteria pollutant, 25 tpy of HAP in aggregate, or ten tpy 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 2020, 35 oil and gas sources operated under Tribally-issued Title V

permits.

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 2020 fee calculation worksheets submitted by each source to the Tribe. Actual

emissions data were available for all 35 Title V oil and gas sources. GHG emissions, reported

as carbon dioxide equivalent (CO2e) were obtained from fee calculation worksheets (if

provided) and if not, the PTE listed in their most recent Title V permit renewal was used and

cross checked with EPA Facility Level Information on GreenHouse Gases Tool (FLIGHT) at

https://ghgdata.epa.gov/ghgp/main.do. This data collection methodology adheres to the

EPA level II EI guidelines for utilizing measured data when available.

Emissions

Total criteria pollutant, HAP, and GHG emissions estimated from Title V sources for the 2020

calendar year are displayed below in Table 1.

Table 1: Title V criteria pollutant, HAP, and GHG emissions estimations [tons] *

Pollutant

NOx

VOC

SO2

Total HAP

GHG

Emissions 2,359.8 1,032.9 46.9 101.9 1,872.9

306.1

2,124,765.3

*CO2e emissions for all Title V sources are reported values obtained from annual Title V fee forms

and EPA GHG data and are reported in metric tonnes

Total criteria pollutant and HAP emissions by equipment type from Title V sources for the

2020 calendar year are displayed below in Figures 3 through 5.

Figure 3: Criteria pollutant and HAP emissions at Title V sources [tons]

Title V Criteria Pollutant and HAP Emissions

for the Southern Ute Indian Reservation in CY

2020 (tons)

306.1

2,359.8

1,872.9

101.9

46.9

NOx

1,032.9

VOC

SO2

Total HAP

Figure 4: NOx and CO emissions from Title V sources by equipment type [tons]

1,573.7

2,000.0

1,821.7

Title V NOx and CO Emissions by Equipment

Type (tons)

5.3

1.0

4.9

20.7

104.6

500.0

136.2

376.9

1,000.0

160.3

1,500.0

Engine

Turbine

Heater

NOx

Boiler

Other

*”Other” includes emissions from amine units, excess emission events, blowdowns, maintenance, and fugitive

emission sources

Figure 5: VOC and HAP emissions from Title V sources by equipment type [tons]

681.9

800.0

Title V VOC and Total HAP Emissions by

Equipment Type (tons)

6.5

25.6

46.5

111.5

0.5

19.8

0.0

1.1

2.0

200.0

9.9

90.1

400.0

3.0

247.7

600.0

Engine

Turbine

Heater

Boiler

VOC

Tank

Dehydrator

Other

Total HAP

*”Other” includes emissions from amine units, excess emission events, blowdowns, maintenance, and fugitive

emission sources

Speciated HAP emissions from Title V sources are displayed below in Table 2 and Figure 5.

Table 2: Title V HAP emissions [tons]

Pollutant Formaldehyde Benzene Toluene Ethylbenzene Xylenes Acetaldehyde Acrolein Methanol n-Hexane

Emissions

210.5

8.7

20.8

6.9

27.2

18.9

11.0

4.3

0.9

Figure 5: Title V speciated HAP emissions [tons]

Title V Speciated HAP Emissions (tons)

250.0

210.5

200.0

150.0

100.0

50.0

8.7

20.8

0.0

2. Minor Oil and Gas Point Sources

6.9

27.2

18.9

11.0

4.3

0.9

The Tribal Minor New Source Review (TMNSR) permitting program is found at 40 CFR Part

§49.151 through §49.164.3 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 Table 3 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 Table 3.

Table 3: 40 CFR Part 49 Minor New Source Review Program Emissions Thresholds

Regulated NSR Pollutant

Carbon Monoxide (CO)

Nitrogen Oxides (NOx)

Sulfur Dioxide (SO2)

Volatile Organic Compounds (VOC)

PM Total

PM10

PM2.5

Lead

Fluorides

Sulfuric Acid Mist

Hydrogen Sulfide (H2S)

Total Reduced Sulfur (including H2S)

Reduced Sulfur Compounds (including H 2S)

Municipal Waste Combustor Emissions

Municipal Solid Waste Landfill Emissions (measured

as non-methane organic compounds)

Minor NSR Thresholds for

Attainment/ Unclassifiable

[tpy]

0.1

A. Synthetic minor 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”.

3 40 CFR Part 49 - Indian Country: Air Quality Planning and Management. (2020). 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

During calendar year 2020, eleven sources on the Reservation operated under TMNSR

permits. Of the eleven sources in this category, nine sources are natural gas compressor

stations, and one source is a natural gas processing plant. Five sources have permits to

reduce emissions below Title V permitting thresholds and six sources have permits for

various other reasons.

Data Collection

Only the five oil and gas sources with TMNSR permitted emissions below the Title V

permitting thresholds were included in this category to avoid double counting emissions.

Emissions from the remaining six oil and gas sources, which also 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.

Synthetic minor 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

20204. For the pollutants and emission units that were not reported to EPA Region 8,

AQP calculated emissions or utilized data that was submitted for its 2017 emission

inventory. If actual operating hours were not available, maximum operating hours were

used. This data collection methodology adheres to the EPA level II EI guidelines for using

measured data when available.

Emissions

Total 2020 criteria pollutant, HAP, and GHG emissions from permitted TMNSR oil and gas

sources on the Southern Ute Indian Reservation are presented below in Table 4.

Table 4: Criteria Pollutant, HAP, and GHG emissions for synthetic minor sources [tons]*

Pollutant

NOx

VOC

SO2

Total HAP

GHG (CO2e)

Emissions 253.9 137.5 126.2

*GHG emissions reported in tonnes.

3.8

5.9

29.7

69931.4

Total criteria pollutant and HAP emissions from synthetic minor sources on the Southern

Ute Indian Reservation by equipment type are presented below in Figure 6, Figure 7, and

Figure 8.

Figure 6: Criteria pollutant and HAP emissions from synthetic minor sources [tons]

Emissions from Southern Ute Indian Tribe (2021). CY 2020 EPA TMNSR Fee Forms.

Synthetic Minor Source Criteria Pollutant

and HAP Emissions (tons)

29.7

137.5

253.9

126.2

3.8

5.9

NOx

VOC

SO2

Total HAP

Figure 7: NOx and CO emissions from synthetic minor sources by equipment type [tons]

250.0

200.0

150.0

131.4

300.0

248.2

Synthetic Minor Source NOx and CO

Emissions by Equipment Type (tons)

Engine

Heater

Boiler

NOx

Dehydrator

1.6

0.3

1.3

1.5

0.1

0.0

0.1

3.8

50.0

3.1

100.0

Other

*”Other” includes emissions from insignificant emission units

Figure 8: VOC and HAP emissions from synthetic minor sources by equipment type [tons]

120.0

100.0

97.4

Synthetic Minor Source VOC and Total

HAP Emissions by Equipment Type (tons)

80.0

Engine

Heater

Tank

VOC

2.1

6.1

Dehydrator

0.0

0.2

20.0

1.1

14.4

22.4

40.0

12.1

60.0

Other

Total HAP

*”Other” includes emissions from insignificant emission units

Total 2020 speciated HAP emissions from synthetic minor sources on the Southern Ute

Indian Reservation are displayed below in Table 5 and Figure 9.

Table 5: Speciated HAP emissions from synthetic minor sources [tons]

Pollutant

Emissions

Formaldehyde

14.6

Benzene

0.7

Toluene

2.2

Xylenes

4.1

Acetaldehyde

3.7

Acrolein

2.3

Methanol

0.9

Figure 9: Speciated HAP emissions from synthetic minor sources [tons]

Synthetic Minor Source Speciated HAP

Emissions (tons)

16.0

14.0

12.0

10.0

8.0

6.0

4.0

2.0

0.0

14.6

4.1

0.7

2.2

3.7

2.3

B. Registered Tribal Minor New Source Review Oil and Gas Sources

Description of Sources

0.9

1.0

n-Hexane

1.0

The TMNSR program required operators of true minor sources, as defined in §49.152, to

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.

For CY 2020, the AQP had record of 238 active oil and gas source registrations for the

Reservation.5 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 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 true minor

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 Section 114 ICR in June 2021 to obtain updated and

reconciled registration data for true minor sources from each facility operator. The ICR

included data for registered oil and gas sources. Specifically, the ICR requested

reconciliation of the operational status of each previously registered true minor source,

equipment located at each source, and the actual emissions for calendar year 2020.

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 anticipated that the ICR could also 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

Southern Ute Indian Tribe. (2021). Information Collection Request.

Total 2020 emissions of criteria pollutants, HAP, and GHG from true minor sources on the

Reservation are displayed below in Table 6.

Table 6: Criteria pollutant and HAP emissions from true minor sources [tons] *

Pollutant

NOx

VOC

SO2

Total HAP

GHG (CO2e)

Emissions

4,575.2

3,248.1

834.5

42.8

16.1

291.0

1,568,843.6

*GHG emissions reported in metric tonnes.

Total 2020 criteria pollutant and HAP emissions from true minor sources on the

Reservation by equipment type are displayed below in Figures 10 through 12. GHG

emissions from true minor sources are displayed below in Figure 13.

Figure 10: Criteria pollutant and HAP emissions from true minor oil and gas sources [tons]

True Minor Oil and Gas Source Criteria

Pollutant and Total HAP Emissions (tons)

291.0

3,248.1

4,575.2

42.8

16.1

834.5

NOx

VOC

SO2

Total HAP

Figure 11: NOx and CO emissions from true minor oil and gas sources by equipment type

[tons]

4,446.9

True Minor Oil and Gas Source NOx and CO

Emissions by Equipment (tons)

3,149.0

5,000.0

4,000.0

3,000.0

23.0

26.2

0.8

1.1

6.1

7.5

57.5

11.7

21.9

1,000.0

71.6

2,000.0

Engine

Turbine

Heater

Boiler

NOx

Dehydrator

Other

*”Other” consists of combustors, flares, and undefined equipment

Figure 12: VOC and HAP emissions from true minor oil and gas sources by equipment type

[tons]

Heater

Boiler

VOC

Tank

Dehydrator

Fugitives

8.1

2.5

0.6

28.5

8.5

13.7

1.0

115.3

Turbine

3.9

0.2

0.6

Engine

61.6

309.1

162.8

450.0

400.0

350.0

300.0

250.0

200.0

150.0

100.0

50.0

409.0

True Minor Oil and Gas Source VOC and HAP

Emissions by Equipment Type (tons)

Other

Total HAP

*”Other” consists of combustors, flares, and undefined equipment

Figure 13: GHG emissions from true minor oil and gas sources by equipment type [tonnes]

450.0

409.0

True Minor Oil and Gas Source VOC and HAP

Emissions by Equipment Type (tons)

309.1

400.0

350.0

2.5

0.6

28.5

8.5

1.0

3.9

0.6

50.0

0.2

100.0

13.7

150.0

8.1

200.0

115.3

162.8

250.0

61.6

300.0

Engine

Turbine

Heater

Boiler

VOC

Tank

Dehydrator

Fugitives

Other

Total HAP

*”Other” consists of combustors, flares, and undefined equipment

3. Permitted Point Sources

In 2020, the one non-oil and gas point source operating under a TMNSR permit on the

Reservation is a gravel pit. The operator reported the facility did not operate in 2020 and

therefore, no emissions were reported for the source.

Table 7: Criteria pollutant and HAP emissions from permitted non-oil and gas point sources

[tons]

Pollutant

Emissions

NOx

VOC

PM10

PM2.5

SO2

Total HAP

CO2e

4. 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 Recycling Center and Depository

(Bondad Landfill) located in Bondad, Colorado and the second one is the Archuleta County

Landfill, located south of Pagosa Springs, Colorado. Both MSW disposal sites accept nonhazardous 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

The Archuleta County Landfill submitted acceptance volumes for 2018, 2019, and 2020 for

input in LandGEM 3.02 with a density 0.79 Megagram/cubic yard. The density was estimated

from the reported Megagrams per cubic yard for the years 2013 through 2015. All reports

were previously submitted by Archuleta County to the CDPHE. Emissions data for the Bondad

Landfill were directly obtained from the CY 2020 Title V emissions fee form submitted to the

Tribe.

Emission Calculation Methodology

Emissions for the Archuleta County landfill were estimated using the EPA’s MSW landfill

emissions model, LandGEM version 3.02 (LandGEM).6 Emissions data for the Bondad Landfill

were obtained from the CY 2020 Title V emissions fee form submitted to the Tribe by Transit

Waste, LLC, who ran LandGEM to estimate emissions from this facility. 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.

Q CH 4  

i1

 M i 

 kL  10  e

j  0 .1

 kt ij

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

U.S. EPA - Landfill Gas Emissions Model. (2021). Retrieved from https://www.epa.gov/catc/clean-air-technologycenter-products#software.

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 default 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 year -1

(an arid area that receives less than 25 inches of rain annually) and a L o-value of 170 cubic

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 AP42, Fifth Edition Compilation of Air Emission Factors (EPA AP-42).7 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 2020. 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 2018-2020 along with the

historical data submitted

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 IV.1 of this report.

Total refuse in place in tons and total emissions of GHG, VOC and HAP from MSW landfills on

the Reservation for 2020 are displayed below in Table 8 and Figure 14.

Table 8: Municipal solid waste landfill refuse in place [tons] and emissions [tons] *

Refuse in Place

GHG

VOC

HAPs¹

Bondad Landfill

1,667,802

4,846.5

4.6

1.7

Archuleta County Landfill

548,775

18,380.2

2.5

1.9

Totals

2,216,577

23,226.7

7.1

3.6

An insignificant quantity of double counting of VOCs occurs because many reported HAPs are also

considered VOCs.

Figure 14: Municipal solid waste landfill emissions [tons]

U.S. Environmental Protection Agency. (2020). AP-42: Compilation of Air Emission Factors. Retrieved from

https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors.

Landfill VOC and Total HAP Emissions

(tons)

5.0

4.6

4.0

3.0

2.5

1.9

1.7

2.0

1.0

0.0

Bondad

Archuleta

VOC

Total HAP

5. 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 CY 2018 data from EPA’s National Emissions Inventory database (NEI),

which includes total landing and take-off cycles (LTOs) and piston and turbine engine

emission estimates for the heliport, taxi, and general aviation at the Animas Air Park. 8 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. 9

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

U.S. EPA National Emission Inventory Emissions Inventory System. (2020). Retrieved from

https://www.epa.gov/air-emissions-inventories/national-emissions-inventory-nei.

Eastern Research Group. (2001, January). Documentation for Aircraft Component of the National Emissions

Inventory Methodology. (ERG No. 0245.03402.011).

Calendar year 2020 airport emissions are assumed to be similar to emissions from the

airports during CY 2018.

Emissions

Total criteria pollutant and HAP emissions from airports on the Reservation for 2020 are

displayed in Table 9 and Figure 15 and Figure 16 below.

Table 9: Criteria pollutant and HAP emission from airports [tons] *

Durango-La Plata County

NOx

0.01

0.40

36.07

VOC

0.01

0.84

13.09

SO2

0.00

0.08

4.94

PM2.5

0.01

0.51

3.29

PM10

0.01

0.66

3.83

Lead

0.00

0.03

0.1

0.27

30.93

185.91

Total HAP

0.00

0.31

3.59

Totals

36.47

13.94

5.02

3.81

4.50

0.13

217.11

3.90

Animas Air Park Heliport

Animas Air Park

*Emissions estimations for airports are from the 2018 EPA National Emission Inventory Database and

assumed to be realistic estimations of airport emissions for 2020.

Figure 15: CO and NOx emissions from airports [tons]

Airport NOx and CO Emissions (tons)

200.0

180.0

160.0

140.0

120.0

100.0

80.0

60.0

40.0

20.0

0.0

185.9

30.9

0.01

0.3

Animas Airpark Heliport

36.07

0.40

Animas Airpark

NOx

Durango - La Plata

Figure 16: VOC and Total HAP emissions from airports [tons]

Airport VOC and Total HAP Emissions

(tons)

13.1

14.0

12.0

10.0

8.0

6.0

3.6

4.0

2.0

0.0

Animas Airpark Heliport

0.8

Animas Airpark

VOC

0.3

Durango - La Plata

Total HAP

Non-Point Sources

1. Small Oil and Gas Sources

Description of Sources

For the purpose of this EI small 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 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 small oil and gas sources was obtained through a mandatory Clean

Air Act Section 114 ICR issued by the AQP in June of 2021 to each known operator with

sources operating on the Reservation. To identify the operators within the Reservation and

estimate the total number of small oil and gas sources on the Reservation, the AQP compiled

site and ownership data from the COGCC and Drilling Edge databases. 10,11

The ICR was the basis for collecting the information necessary to calculate emissions from

small oil and gas sources and required each recipient to provide actual equipment counts

COGCC. (2020). Production Data. La Plata. Retrieved from http://cogcc.state.co.us/data2.html#/downloads.

Drilling Edge Database (2016). Retrieved from http://www.drillingedge.com/colorado.

and production information. 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 27 of the 32 (84%) companies that reported production

on the Reservation in CY 2020 to the COGCC database. The completed ICRs accounted for

2,570 of the 2,582 (99.5%) known small oil and gas sources on the Reservation. The AQP

used 2017 ICR submitted information for the remaining unreported sources.

Calculation Methodology

The AQP calculated emissions for small oil and gas sources on an equipment basis using

measured data, widely accepted emission factors and emission calculation methodologies,

the equipment counts reported in the ICR, and CY 2020 production data from the COGCC.

Descriptions of how emissions were calculated for each equipment type are included later in

this section.

Emissions

Criteria pollutant, HAP, and GHG emission estimations from small oil and gas sources on the

Reservation in 2020 are displayed below in Table 10.

Table 10: Emissions from small oil and gas sources [tons]*

Pollutant

NOx

VOC

SO2

Total HAP

GHG

Emissions

11,664.0

798.8

5.6

183.8

9,716.6

233.9

1,575,054.1

*GHG emissions reported in metric tonnes.

Criteria pollutant, HAP, and GHG emissions from small oil and gas sources on the Reservation

by equipment type are displayed below in Figures 17 through 20.

Figure 17: Criteria pollutant and HAP emissions from small oil and gas sources [tons]

Small Oil and Gas Source Criteria

Pollutant and Total HAP Emissions

(tons)

233.8

9,716.6

11,664.0

183.8

NOx

5.6

798.9

VOC

SO2

Total HAP

Figure 18: NOx and CO emissions from small oil and gas sources by equipment type [tons]

Small Oil and Gas Source NOx and CO

Emissions by Equipment Type (tons)

12,000.0

10,000.0

11,124.9

9,264.2

8,000.0

6,000.0

4,000.0

2,000.0

0.8

Engine

537.7

0.2

Turbine

NOx

451.7

Heater

0.6

0.5

Boiler

Figure 19: VOC and HAP emissions from small oil and gas sources by equipment type

[tons]

278.4

Small Oil and Gas Source VOC and Total HAP

Emissions by Equipment Type (tons)

10.2

146.4

0.1

42.9

0.0

0.1

19.4

2.1

0.0

50.0

29.2

100.0

7.4

150.0

8.7

110.3

200.0

0.4

250.0

172.2

205.1

300.0

VOC

Pneumatics

Recompletions

Blowdowns

Fugitives

Dehydrator

Tank

Boiler

Heater

Turbine

Engine

Total HAP

Figure 20: GHG emissions from small oil and gas sources by equipment type [tonnes]

586,063.8

Small Oil and Gas Source GHG (CO 2 e) Emissions by

Equipment Type (tonnes)

400,000.0

217,529.5

500,000.0

298,443.7

600,000.0

432,779.0

700,000.0

27,232.2

182.2

100,000.0

372.4

255.9

698.0

200,000.0

11,451.6

300,000.0

2020 Speciated HAP emissions are displayed below in Table 11 and Figure 21.

Table 11: Speciated HAP emissions from small oil and gas sources [tons]

Pollutant

Formaldehyde

Benzene

Toluene

Ethylbenzene

Xylenes

Acetaldehyde

Acrolein

Methanol

n-Hexane

Emissions

143.9

8.1

7.8

0.8

4.9

20.3

18.4

11.6

20.7

Figure 21: Speciated HAP emissions from small oil and gas sources [tons]

Small Oil and Gas Source Speciated HAP

Emissions (tons)

160.0

140.0

120.0

100.0

80.0

60.0

40.0

20.0

0.0

143.9

8.1

7.8

0.8

4.9

20.3

18.4

11.6

20.7

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), fourstroke rich-burn (4SRB), and diesel. 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 at small oil and gas sources on the Reservation in 2020 are

displayed below in Figure 22.

Figure 22: Engine counts by engine configuration and horsepower at small oil and gas

sources

Engine Counts by Engine Configuration and

Horsepower at Small Oil and Gas Sources

600

481

500

400

246

300

200

100

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 (if the operator did not input anything more

representative of their operating conditions), an assumed 100% engine operating load,

and assumed operating schedule of 8,760 hours per year (if the operator did not input a

different number of annual operating hours). The assumed BSFC value was derived by

averaging the BSCF from all natural gas-fired engines in the Caterpillar Gas Engine Rating

Pro software.12 All emissions were calculated for uncontrolled operation. The natural gas

on the Reservation contains negligible amounts of sulfur, therefore SO 2 emissions from

engines are minimal.

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.13

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 CFR Part 98 - Mandatory Greenhouse Gas Reporting. (2021). 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.

Example Calculation

Calculation of engine heat rate (MMBtu/hr) using AQP’s assumed brake specific fuel

consumption (Btu/hp-hr):

HR (MMBtu/hr) = BSFC (7500 Btu/hp-hr)/10^6 x hp

Where:

HR = heat rating (MMBtu/hr)

BSFC = brake-specific fuel consumption

hp = engine horsepower

Engine emission calculation:

tpy = (EF) x HR x OH/2000 pounds/ton

Where:

tpy = tons per year

EF = emission factor (lb/MMBtu)

HR = heat rate

OH = annual operating hours

Example Nox emissions calculation for a 200 hp four-stroke rich-burn engine operating

8,760 hours per year:

tpy = (2.21 lb/MMBtu) x (1.5 MMBtu/hr) x (8760 hr)/2000 lb/ton = 14.52 tpy Nox

Emissions

Total criteria pollutant, HAP, and GHG emissions from natural gas-fired RICE at small oil

and gas sources are displayed below in Table 12 and Figures 23 and 24.

Table 12: Natural gas-fired reciprocating internal combustion engine counts and criteria

pollutant, HAP, and GHG emissions for small oil and gas sources [tons] *

Engine Configuration

and Horsepower (hp)

2SLB 0-50 hp

2SLB 51-100 hp

2SLB 101-200 hp

2SLB 201-300 hp

Number of

Engines

NOx

VOC

SO2

Total

HAP

GHG

170.8

61.3

774.3

270.0

6.5

2.3

29.3

10.2

0.0

0.1

4.1

1.5

18.8

6.5

20.8

7.5

94.3

32.9

4.2

1.5

18.8

6.7

5,722.5

2,055.0

25,948.5

9,046.7

1,707.8

64.6

1,062.2

40.2

472.4

13.7

361.9

10.5

788.1

22.8

35.7

1.0

148.7

4.3

59.4

1.7

93.8

2.7

1,715.2

23.0

1,785.7

23.9

900.9

12.1

106.9

1.5

203.3

2.7

87.1

1.2

254.1

3.4

65.3

0.9

11,059.6 277.6

2SLB 301-400 hp

2SLB 501-600 hp

4SLB 0-50 hp

4SLB 51-100 hp

4SLB 101-200 hp

4SLB 201-300 hp

4SLB 301-400 hp

4SLB 401-500 hp

4SLB 601-700 hp

4SRB 0-50 hp

481

4SRB 51-100 hp

246

4SRB 101-200 hp

4SRB 201-300 hp

4SRB 301-400 hp

4SRB 501-600 hp

4SRB 601-700 hp

4SRB 801-900 hp

Totals:

1104

GHG reported in metric tonnes.

0.3

0.2

0.1

0.0

0.5

0.2

0.0

0.1

0.0

0.1

0.0

2.4

41.4

25.7

0.0

14.8

15.4

7.7

0.9

1.7

0.6

2.2

0.6

141.5

208.0

129.3

36.7

28.1

61.2

2.8

11.6

4.6

7.3

2,887.2

3,005.7

1,516.5

183.3

342.2

146.6

427.7

110.0

9,154.2

41.5

25.8

8.4

6.3

13.7

0.6

2.4

1.0

1.6

24.3

25.3

12.8

1.5

2.9

1.2

3.6

0.9

204.2

57,232.6

35,595.9

12,301.5

9,422.4

20,520.4

928.6

3,872.2

1,547.7

2,442.9

82,450.5

85,836.0

43,306.7

5,234.7

9,771.4

4,187.7

12,214.3

3,140.8

429,638.2

Figure 23: CO and NOx emission from small oil and gas sources by engine type [tons]

500.0

1,516.5

3,005.7

106.9

183.3

203.3

342.2

87.1

146.6

254.1

427.7

65.3

110.0

1,000.0

170.8

20.8

61.3

7.5

1,500.0

774.3

94.3

270.0

32.9

2,000.0

208.0

1,707.8

2,500.0

1,062.2

129.3

472.4

36.7

361.9

28.1

788.1

61.2

35.7

2.8

148.7

11.6

59.4

4.6

93.8

7.3

1,715.2

3,000.0

900.9

3,500.0

1,785.7

2,887.2

Small Oil and Gas Source Engine NOx and CO Emissions

by Engine Type (tons)

4SRB 801-900 hp

4SRB 601-700 hp

4SRB 501-600 hp

4SRB 301-400 hp

4SRB 201-300 hp

4SRB 101-200 hp

4SRB 51-100 hp

4SRB 0-50 hp

4SLB 601-700 hp

4SLB 301-400 hp

NOx

4SLB 401-500 hp

4SLB 201-300 hp

4SLB 101-200 hp

4SLB 51-100 hp

4SLB 0-50 hp

2SLB 501-600 hp

2SLB 301-400 hp

2SLB 201-300 hp

2SLB 101-200 hp

2SLB 51-100 hp

2SLB 0-50 hp

Figure 24: VOC and Total HAP emissions from small oil and gas sources by engine type

[tons]

64.6

Small Oil and Gas Source Engine VOC and Total HAP

Emissions by Engine Type (tons)

70.0

41.5

40.2

60.0

20.0

10.0

6.5

4.2

2.3

1.5

30.0

18.8

10.2

6.7

40.0

25.8

13.7

8.4

10.5

6.3

22.8

13.7

1.0

0.6

4.3

2.4

1.7

1.0

2.7

1.6

23.0

24.3

23.9

25.3

12.1

12.8

1.5

2.7

2.9

1.2

3.4

3.6

0.9

29.3

50.0

VOC

4SRB 801-900 hp

4SRB 601-700 hp

4SRB 501-600 hp

4SRB 301-400 hp

4SRB 201-300 hp

4SRB 101-200 hp

4SRB 51-100 hp

4SRB 0-50 hp

4SLB 601-700 hp

4SLB 401-500 hp

4SLB 301-400 hp

4SLB 201-300 hp

4SLB 101-200 hp

4SLB 51-100 hp

4SLB 0-50 hp

2SLB 501-600 hp

2SLB 301-400 hp

2SLB 201-300 hp

2SLB 101-200 hp

2SLB 51-100 hp

2SLB 0-50 hp

Total HAP

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 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.14 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 small oil and gas 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 11,000 Btu/hphr.

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 AP-42,

100% engine operating load, an operating schedule of 8,760 hours per year and a

reported BSFC of 11,000 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 SO 2 emissions from turbines

are minimal.

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 2020 are displayed in Table 13.

Table 13: Turbine count and criteria pollutant, HAP, and GHG emissions at small oil and

gas sources [tons]*

Turbine configuration

and horsepower

Number of

turbines

NOx

PM10

VOC

Total

HAP

GHG

(CO2e)

Lean-Premix 0-50 hp

0.77

0.20

0.02

0.01

0.00

255.92

*GHG reported in metric tonnes.

C. Tri-Ethylene Glycol Dehydration Units

Description of Units

McGowin (1973) Stationary Combustion Turbines in the United States.

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 stillvent. 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 at small oil and

gas sources on the Reservation during calendar year 2020. 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 of the operators’ operations. The theoretical extended gas analysis

is displayed below in Table 14.

Fifty 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. 15

GLYCalc is the EPA’s preferred method of quantifying emissions from glycol dehydration

units for the development of tribal/state/local emissions inventories. 16

Product of combustion emissions from dehydration unit reboilers were included in the

emission totals for heaters and boilers presented in Section V.1.E. of this report to avoid

double counting.

Gas Research Institute. (2000). GLYCalc Version 4.0. Retrieved from http://sales.gastechnology.org/000102.html.

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.

Table 14: Theoretical extended natural gas analysis – average of 31 natural gas analyses

from the Southern Ute Indian Reservation

Component

Methane

Ethane

Propane

Isobutane

n-Butane

Isopentane

n-Pentane

n-Hexane

Carbon Dioxide

Nitrogen

Hydrogen Sulfide

2,2 Dimethylbutane

2,3 Dimethylbutane

Cyclopentane

2-Methylpentane

3-Methylpentane

2,2 Dimethylpentane

Methylcyclopentane

2,4-Dimethylpentane

2,2,3-Trimethylbutane

Benzene

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

Total:

Total VOC:

Average

92.3814%

0.9867%

0.2291%

0.0349%

0.0468%

0.0107%

0.0070%

0.0028%

6.1663%

0.1134%

0.0000%

0.0003%

0.0004%

0.0029%

0.0012%

0.0000%

0.0012%

0.0000%

0.0005%

0.0000%

0.0008%

0.0002%

0.0000%

0.0002%

0.0000%

0.0002%

0.0028%

0.0021%

0.0010%

0.0017%

0.0001%

0.0000%

0.0002%

0.0003%

0.0001%

0.0008%

0.0006%

100.00%

0.35%

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 small oil and gas sources provided by two of the largest operators

on the Reservation. An assumed extended natural gas analysis was prepared by

averaging 31 individual extended gas analyses from natural gas production sector

compressor stations that were reported to the AQP in Title V operating permit

applications between 2017 and 2020.

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.

The assumed GLYCalc input parameter values are provided below in Table 15.

Table 15: GRI-GLYCalc Model input parameters for TEG Dehydration units at small oil

and gas sources

Wet Gas Temperature [°F]

Wet Gas Pressure [psig]

Dry Gas Flowrate/ Throughput [MMscf/day]

Lean Glycol Water Content [weight % H2O]

Glycol Pump Type

Pipeline Water Content Specification [lb H2O/MMscf]

68.5

353.5

0.9

1.5

Electric/ Pneumatic

7.0

GRI-GLYCalc Model Emissions Output:

Fifty dehydration units were reported for small oil and gas sources 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 50 dehydration

units reported in the ICR, and then summed to derive a reservation-wide emissions

estimate for glycol dehydration units located at small 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 Table 16.

Table 16: GRI-GLYCalc Model emissions output for TEG Dehydration units [tons]

Pollutant

Methane

Ethane

Propane

Isobutane

n-Butane

Isopentane

n-Pentane

Cyclopentane

n-Hexane

Cyclohexane

Other Hexanes

Heptanes

Methylcyclohexane

2,2,4-Trimethylpentane

Benzene

Toluene

Ethylbenzene

Xylenes

C8+ Heavies

Total HC Emissions

Total VOC Emissions

Total HAP Emissions

Total BTEX Emissions

Uncontrolled

Emissions

0.2341

0.0226

0.0211

0.0076

0.0156

0.0057

0.0050

0.0000

0.0080

0.0048

0.0000

0.0097

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 2020

ICR Reported Dehydration Units

Example:

24.2 tpy annual VOC emissions = 0.4399 tpy VOC x 50 reported dehydration units

Emissions

VOC and HAP emissions from 50 TEG Dehydration Units at small oil and gas sources on

the Reservation are provided in Table 17.

Table 17: VOC and HAP Emissions from TEG Dehydration Units from small oil and gas

sources [tons]

Totals

Number of

Dehydration Units

VOC

19.4

Total

HAP

8.7

Benzene

Toluene

Ethylbenzene

Xylenes

1.0

3.4

0.5

3.6

D. Liquid Storage Tanks

Description of Equipment and Emissions Categories

The oil and gas industry utilize 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.

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 small oil and gas sources on the Reservation.

Reported tank counts were based on tank capacity and contents.

A summary of tanks reported in the ICR, by tank contents, is displayed below in Figure

25.

Figure 25: Liquid storage tanks at small oil and gas sources by tank contents

Small Oil and Gas Source Tank Count

1800

1633

1600

1400

1200

1000

800

600

400

200

Condensate

Oil

Produced Water

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 CY

2020. If data were available from COGCC, the AQP used operator-specific throughput

values and if the data were 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 CY

2020.

Assumed average annual liquid throughput values were developed for operators that

reported active sources to the COGCC in 2020 but did not report production. The

assumed annual throughput value for produced water was derived by dividing the total

CY 2020 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 CY 2020 combined condensate

and oil production value reported to the COGCC database by the number of small oil and

gas sources that reported condensate or oil production. Not all companies reported

condensate or oil production to COGCC, and four 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 small oil and gas sources on the Reservation are displayed

below in Table 18.

Table 18: Assumed annual average liquid throughput values for produced water, oil, and

condensate tanks at small oil and gas sources *

Number of Sources Operating in 2020

2020 Oil/Condensate Produced [bbl]

2020 Water Produced [bbl]

Average Oil/Condensate per source per year [bbl]

Average Water per source per year [bbl]

2,903

13,933

9,018,787

0.12

1,361

Throughput numbers were derived from averaging production numbers from COGCC (2020).

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 normal tank operation at atmospheric pressures, as

described earlier in this section. The emissions categories include: breathing and working

losses, flash emissions, and loadout emissions. Discussions are provided below the

methodologies used to calculate emissions for each tank emissions category.

Breathing 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. 17

Reported liquid throughput values were used when provided and assumed throughput

values were used when data was not provided.

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. An equal distribution through all tanks was assumed by dividing the total

production by the total number of tanks in a given category. Produced water was

assumed to consist of a mixture of 99% water and 1% condensate. Condensate was

assumed to have a Reid Vapor Pressure of 10 in the TANKS model. The default values for

crude oil were used for oil tank calculations. The model was run 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 average temperatures in Albuquerque are warmer 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 o

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