Public Comment Draft

PUBLIC COMMENT DRAFT

September 2015

Appendix A, page 1

PUBLIC COMMENT DRAFT

Table ofContents

1Overall Assumptions for Development Phase

2Process Description

3Summary of Emissions

4Emissions Activities and Key Assumptions

4.1Site Preparation: Land Clearing

4.1.1Potential Emission Sources

4.1.2Estimate of Emissions

4.2Transportation

4.2.1Potential Emissions Sources

4.3Unpaved Roads

4.3.1Potential Emission Sources

4.4Drilling

4.4.1Potential Emission Sources

4.4.2Estimate of Emissions

4.5Drilling Mud Storage

4.5.1Potential Emission Sources

4.5.2Estimate of Emissions

4.6Hydraulic Fracturing

4.6.1Potential Emission Sources

4.6.2Estimate of Emissions

4.7Well Completion

4.7.1Potential Emission Sources

4.7.2stimate of Emissions

5References

List of Tables

Table A-1. Criteria Pollutants and Greenhouse Gas Emissions from Well Development

Table A-2. Hazardous Air Pollutant Emissions from Well Development

Table A-3. Estimate of Emissions from Land Clearing

Table A-4. US EPA Definitions of Light Duty and Heavy-Duty Truck Gross Vehicle Weight Class

Table A- 5. US Truck Fleet by Fuel Type…………………………….…………………………………………………………….………11

Table A-6. Summary of Average Number of Truck Trips and Miles Traveled during Well Development

Table A-7. Estimated Vehicle Miles Travelled for Development of One Well

Table A-8. Average Engine Emission Rates by Pollutant and Vehicle Type6,7

Table A-9. Average Truck Idle Time per Well Development

Table A-10. Average Idle Emission Rates by Pollutant for All Vehicle Types

Table A-11. Total Emissions from Truck Trips and Idling per Well Development

Table A-12. Vehicle Miles of Unpaved Road Traveled per Vehicle Type

Table A-13. Emission Factor Parameters for PM10 Emissions from Travel on Unpaved Roads

Table A-14. Fugitive Dust Emissions from Travel on Unpaved Roads

Table A-15. Shale Formation Comparison between NC and other states in US………………………………………18

Table A-16. Drilling Equipment

Table A-17. Emission Factors for Criteria Air Pollutants, Drilling Activity

Table A-18. Emission Factors for Hazardous Air Pollutants, Drilling Activity

Table A-19. Emission Factors and Molar Percentages Used to Estimate Emissions

Table A-20. Hydraulic Fracturing Pump Specifications

Table A-21. Emission Factors for Criteria Air Pollutants, Hydraulic Fracturing Activity

Table A-22. Emission Factors for Hazardous Air Pollutants, Hydraulic Fracturing Activity

Table A-23. Volume Percent by Pollutant

Table A-24. VOC to BTEX Ratios for Dehydrator Emissions

Table A-25. Reboiler Activity Data………………………………………………………………………………………………………..…25

Table A-26 Reboiler Emission Factors……………………………………………………………………………………………………..25

Appendix A, page 1

PUBLIC COMMENT DRAFT

1Overall Assumptions for Development Phase

• Wells will meet emissions requirements in 40 CFR Parts 60 and 63, Oil and Natural Gas Sector; New Source Performance Standards and National Emission Standards for Hazardous Air Pollutants.
• Horizontal drilling techniquesare employed (i.e., vertical drilling occurs until the well bore is near the shale formation, then horizontal drilling occurs through the shale formation.
• Each pad contains 4 wells
• Non-road engines are used for drilling and pumping activities
• Hydraulic fracturing techniques are employed
• Reduced Emissions Completions (Green Completions) will be employed to control flowback emissions per 40 CFR 60 Subpart OOOO.
• No electrification of drilling pads.

2Process Description

Development of natural gas wells involves the various activities to construct and operate the well. Activities in natural gas development include the following:

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PUBLIC COMMENT DRAFT

• Exploration, Leasing, and Permitting
• Site Preparation
• Transportation of Equipment, Supplies, and Waste
• Well Drilling and Casing
• Well Perforationand Hydraulic Fracturing
• Well Completion

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This Appendix discusses estimating emissions from site preparation, transportation, and well drilling, fracturing, and completion. Emissions from explorationand its associated activities are not addressed.

Well development activities in the Sanford Sub-basin willbe performed by many different companies and crews of workers, including construction crews, drilling crews, transporters, and pipeline companies. The companies may choose a variety of approaches to complete theirwork. Therefore, significant changes to the emissions estimates presented in this section may occur as plans to develop the shale gas field become more definite.

Currently North Carolina does not have any natural gas production wells. Any well development activity will be subject to both 40 CFR Parts 60 and 63, Oil and Natural Gas Sector; New Source Performance Standards and National Emission Standards for Hazardous Air Pollutants Reviews and any existing applicable state regulations.

Development activities are generally conducted sequentially; therefore the emissions from each activity, such as pad development, drilling, and fracturing, do not occur at the same time. The total emissions impact to Sanford, Moore and Lee Counties is a function of the number of wells drilled simultaneously.

There is a possibility that both vertical wells (drilling only vertically) and horizontal wells (drilling first vertically then horizontally) could be drilled within the basin. For this study, the DAQ assumed all wells were drilled horizontally since this was the assumption used by Dr. Ken Taylor to derive Table2 Annual Gas Production Estimate of the Narrative. As discussed previously, under this scenario,121new wells are developed in the Sanford Sub-Basin during Year 6 which is the maximum production year.

Each of the activities associated with well development will be discussed in greater detail in the following sections.

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3Summary of Emissions

TableA-1. Criteria Pollutants and Greenhouse Gas Emissions from Well Development

*Assigned based on PM10

**No published EF identified

TableA-2. Hazardous Air Pollutant Emissions from Well Development

ƗHAP emission factors were not available for Not Permitted activities

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4Emissions Activities and Key Assumptions

4.1Site Preparation: Land Clearing

A shale gas well requires a prepared area on the surface or a paved pad that provides a stable base for a drill rig and its support equipment, engines to power the rig, fuel storage, retention ponds for drilling fluids, water storage tanks, truck loading areas, and associated piping. The size of the pad depends on the depth of the well, the number of wells drilled on the site, the size of retention ponds and/or storage tanks, and the area required for storing equipment. In addition, access roads are constructed to support transportation of equipment and supplies to the well. These roads are usually unpaved since they are temporary and the land will be reclaimed after the well has been abandoned. Lastly, pipelines are constructed to transport the raw gas from the well to a processing plant, distribution system, or end user.

4.1.1Potential Emission Sources

As stated previously, site preparation includes all activities associated with constructing roads, well pads, pipelines, and other infrastructure. Potential sources of emissions include;

1)fugitive dust from clearing land,

2)engine emissions from construction equipment

3)emissions from burning of vegetation

4)transportation of site workers

Construction operations are significant source of dust emissions that may have a substantial short-term impact on local air quality. Dust emissions during the construction of well pads or roads are associated with land clearing, and earth moving operations (cut and fill). Dust emissions can vary substantially from day to day, depending on the level of activity, the type operation, and the meteorological conditions.

The DAQ estimated particulate material with a diameter less than 10 microns (PM10) fugitive dust emissions from land clearing for this report. This included assessing the impact of land clearing for constructing well pads, utility pipeline and roads.

The clearing of land for the construction of new roads often results in debris consisting of trees, shrubs, andbrush. This debris is often collected in piles and burned. North Carolina open burning rules would apply. The DAQ did not estimate particulate matter emissions from the burning of cleared vegetation since estimates of the activity data, and its duration were not readily available.

Engine emissions from construction equipment were not estimated since it is difficult to estimate the actual number and type of equipment that would be employed at a given time for this activity.

Transportation of site workers was also not evaluated since there are many unknowns associated with this activity such as how far the average site worker would commute and the average number of workers required for a given activity.

4.1.2Estimate of Emissions

Assumptions and Activity Data

Fugitive dust emissions from land clearing are a function of the acreage cleared. In a shale gas fracturing report, the U.S. Department of Energy (US DOE)estimated that a typical horizontal well pad with only one well would be approximately 3 to 4 acres in size1. If multiple horizontal wells are completed from a single well pad, the pad size would increase to 5 to 7 acres1. However, under the latter scenario, fewer well pads are constructed. It takes several days to several weeks to construct a well pad depending on the size and design requirements.

The area cleared for access roads depends on the well pad’s proximity to public roads. The U.S. Department of the Interior (US DOI) estimated that for the Fayetteville shale basin, located in Arkansas,approximately 0.10 miles of roadand 0.55 miles of utility corridor would be required to support a well which is approximately 3.4 acres in total area1.

The DAQ assumed that 4 wells were constructed per pad for a total of 92 pads. For each well pad, the DAQ assumed an average of 6 acres of land is cleared for the well pad and 3.4 acres of land is cleared for road and utility corridor construction. This study also assumes the duration of the activity is 2 weeks.

State and Federal Regulations

There are no federal rules associated with fugitive dust emissions from land clearing and construction.

North Carolina allows burning of vegetation from land clearing. However, a permit is required and there are other restrictions and conditions related to air quality which may apply to a given activity. North Carolina Administrative Code Title 15A Environment and Natural Resources, Subchapter 2D-Air Pollution Control Requirements, Section 0.190026 contains the rules for open burning26. Note there have been changes to this rule in recent years.

Emission Factorsand Estimates

A general emission factor for all types of construction activity is 0.11 tonsPM10/acre-month. This factor is based on a 1996 study conducted by Midwest Research Institute (MRI) for the California South Coast Air Quality Management District (SCAQMD)2. The composite factor of 0.11 tons PM10/acre-month assumes thatall construction activity produces the same amount of dust on a per acre basis. In otherwords, the amount of dust produced is not dependent on the type of construction butmerely on the area of land being disturbed by the construction activity.

Table A-3 given below presents activity data, emission factors and fugitive dust emissions of PM10 from land clearing for one well. This estimate will increase substantially as emissions from laying pipelines are added once that activity becomes more defined.Emissions data is given as tons per day averaged over a 14-day period.

TableA-3. Estimate of PM Emissions from Land Clearing Per Pad and Per Well

4.2Transportation

Development of shale gas wells creates episodic truck traffic, or significant short-term increases in traffic volumeon local roads. Large amounts of drilling,hydraulic fracturing, and production equipment must be transported to the well pad. In addition, large volumes of materialswill need to be delivered to the well pad, such as diesel fuel for running drills and pumps, water for fracturing,and sand or other proppants[1]for fracturing. Lastly, waste materials (both solid and liquid) must be transported away from the site for disposal. The amount of truck traffic is proportional to the depth of the well being drilled.

The drilling and fracturing equipment is only needed for a short time period and must be removed from the site once the activity is completed. Some of the equipment may be moved from well pad to well pad as development occurs. This would reduce the transportation emissions per well as the basin is developed.

There are many unknowns in the sources of equipment, water, and other materials and how far they would need to be transported. The DAQ chose to estimate the amount of truck traffic for the total well development activity using estimates from other shale gas well development sites. These data are also being used by the NC Department of Transportation to estimate local infrastructure impacts19.

4.2.1Potential Emissions Sources

The primary sources of emissions for transportation include the following sources:

• Large trucks to haul equipment
• Tanker trucks for water and wastewater
• Trucks and cargo vans for materials
• Truck idling emissions
• Railroad engine emissions
• Site worker traffic

In the 2012 DENR report, it was assumed that water would be transported from the water source to the well pad by truck for the first several years3. During the middle to late stages of well field development, the water may be delivered by pipeline, if economically feasible. For this study, the DAQ assumed that all the water is delivered by truck.

In addition to vehicle travel on roads, the trucks are assumed to idle at the well pad for significant periods of time. Idling of large diesel engines used for transportation of supplies, in addition to the engines required for drilling and fracturing, results in emissions of criteria and hazardous air pollutants and can impact site workers.

Much of the equipment and materials will be transported from manufacturing facilities by rail to local rail depots and from rail depots by trucks to the well pads. The DAQ did not estimate the increase in emissions due to diesel railroad engines since this data was not readily available.

Site workercommuting was also not estimated for this study. The number of site workers and the average distance they would travel for a given development activity is not documented in the reports reviewed for this study. In addition, site worker commuting is not expected to have a significant impact compared to the average emissions estimated for trucks.

Assumptions – Vehicle Types

The types of vehicles and machinery most commonly used during well development by class are:

Light Duty Vehicleemployee vehicles

Light Duty Vehicledelivery vehicles and trucks

Heavy Duty Vehiclespecialized cement equipment and vehicles

Heavy Duty Vehicleflatbed tractor trailers

Heavy Duty Vehicletrucks to transport water, sand and chemicals

Some of these trucks can weigh as much as 80,000 to 100,000 pounds when fully loaded3. Only the light duty truck and heavy duty truck trips to transport equipment and materials were estimated.

The US EPA classes vehicles by gross vehicle weight rating (GVWR). There are two basic classes of vehicles based on GVWR. Light duty trucks are up to 10,000 pounds in GVWR. Heavy duty trucks range from over 10,000 pound GVWR to upwards of 80,000 pounds GVWR. Table A- 4 shows the US EPA truck classification system. These definitions are used to assign emission factors to the truck trips. The US EPA further breaks down the heavy duty vehicle class into 8 categories. These more detailed heavy duty truck classifications were not used since information on the weight of trucks was not available for this study.

TableA-4. USEPA Definitions of Light Duty and Heavy-Duty Truck Gross Vehicle Weight Class

The number of light duty and heavy duty vehicles using either diesel or using gasoline is based on data contained in the 2012 Annual Energy Outlook (AEO), Reference Case published by the Energy Information Administration (EIA)23. The AEO data tables indicate that 38% of all light duty trucks are use diesel fuel and 92% of all heavy duty vehicles use diesel fuel. The remaining heavy duty truck traffic was assumed to use gasoline. The percent of gasoline and diesel light duty and heavy duty trucks is given in Table A-5.

TableA-5. US Truck Fleet by Fuel Type

Activity Data – Vehicle Miles Traveled

Engine emissions from vehicle traffic on roads are calculated using the number of miles travelled, for each vehicle type. There are a number of sources for total truck trips required to support horizontal drilling and hydraulic fracturing. The DAQ examined data collected by Pennsylvania, New York and Texas. This information is summarized in Table A-63,4,5.