Pamela F. Faggert 

Chief Environmental Officer and 

Vice President-Corporate Compliance 

Dominion Resources Services, Inc. 

5000 Dominion Boulevard, Glen Allen, VA 23060 

Phon~ 804-273-3467 

dom.com 

By Electronic Mail: oilandgas.whitepapers@epa.gov 

June 16, 2014 

RE: White Papers on Methane and VOC Emissions in the Oil and Natural Gas Sector 

Dear Sir or Madam: 

We appreciate the opportunity 

regarding emissions 

to comment on the white papers EPA released on April 15, 2014 

and mitigation techniques for methane and volatile organic compounds 

(VOCs) in the oil and gas sector. It is our understanding 

along with 

that these papers will be used by EPA, 

pursue 

the input received from peer reviewers and the public, to determine how to best 

additional emission reductions from these sources. 

compressors, 

The EPA white papers focus on five distinct parts ofthe oil and gas sector; namely, (1) 

(2) leaks from natural gas production, processing, 

pneumatic devices; 

transmission and storage, (3) 

ongoing production 

(4) liquid unloading processes and (5) emissions from completions and 

of hydraulically 

the state of emissions 

fractured oil wells. The white papers include a review of 

knowledge 

costs 

in these areas, and identify methods, technologies and potential 

and 

to control methane and VOC emissions. We offer comments on the approach, in general, 

operations, 

specific comments on three of the papers that are most relative to Dominion natural gas 

production, 

namely the papers on compressors, pneumatic devices, and leaks from natural gas 

processing, transmission and storage. 

Dominion Energy, Inc. operates natural gas processing, transmission, 

assets 

storage and distribution 

Point, 

in 

Maryland. 

the Appalachian region and the liquefied natural gas (LNG) terminal located in Cove 

Twenty-three 

These assets are an integral parts of the nation's natural gas infrastructure. 

These 

ofthose facilities report methane (greenhouse gas) emissions under Subpart W. 

facilities, 

facilities include eighteen transmission and/or storage compressor stations, two processing 

one LNG Import/Export 

Transmission, 

facility, and two local distribution companies. Dominion 

mitigation 

Inc. (DTI) is a Natural Gas STAR partner company and reports results of selected 

practices under the program annually to EPA. 

mitigation 

We appreciate EPA's efforts to better understand methane emission sources and possible 

use of natural 

practices that can be used to further decrease emissions of greenhouse gases. As the 

opportunities 

gas increases, Dominion is committed to continuing to examine mitigation 

and to implement those that are found to be economically prudent and 
Dominion Energy, Inc. Comments 

EPA Methane Mitigation Technical White Papers 

June 16,2014 

Page 12 

environmentally responsible. We encourage EPA to develop more accurate and current 

emissions estimates for sources in the natural gas industry. In addition, we ask that this process 

fully consider the role of natural gas in the nation's energy future recognizing that natural gas 

combined cycle combustion units generally have half the C02 emissions as generation from 

coal-fired units. 1 Therefore, new natural gas powered generation should be encouraged not 

only nationally, but internationally. 

To date, EPA has relied primarily on two programs to understand methane emissions from the 

natural gas industry, namely the Natural Gas STAR program and the Greenhouse Gas Reporting 

Program (GHGRP). These programs have two separate and distinct purposes- the Natural Gas 

STAR program seeks to identify and document voluntary methane mitigation technologies and 

practices in specific applications in the industry, while the GHGRP collects data on methane 

emissions from the industry as a whole. This distinction is very important in understanding 

where and how this information is most appropriately used in determining economically prudent 

and environmentally impactful reduction opportunities. The information available from the 

Natural Gas STAR program can help answer what technologies and practices may be beneficial 

over a larger population of sources, but in some cases further verification is warranted to 

determine long term performance when compared to alternatives at particular sources. The 

GHGRP, on the other hand, has collected data on methane emissions over the past three years. 

This data has been used to identify the major sources of methane emissions in the industry and 

may be used to determine where mitigation technologies could be most beneficial. In some 

cases, such as pneumatics, leaks at measuring and regulating (M&R) sites for the distribution 

sector, vapor recovery units at LNG facilities, and pipeline services and mains, emissions are 

based on "average" emission factors that were developed in the late 1990s and which may not 

reflect current practices. To fully understand where emissions can be mitigated it is necessary to 

understand not only the average emissions, but the range of emission rates over a larger 

population. Recent studies, referenced below, have indicated that a small number of sources are 

responsible for the majority of emissions. While the data from the GHGRP can serve to inform 

mitigation policies, the underlying measurement and calculation methodologies need to be 

considered so that the data is used appropriately whether direct measurement, population counts, 

or survey-specific emission factors. 

As EPA moves towards a broader methane reduction strategy, including future potential 

regulation, we ask that EPA continue to work with industry to more fully analyze and understand 

the information that has been developed thus far, to identify gaps in our understanding that must 

be filled to move forward with a sound scientific basis, and to cooperatively develop and 

implement a strategy to address those gaps. 

The White Papers are a reasonable starting point for obtaining more information on the state of 

knowledge regarding emission sources and possible mitigation methodologies. However, more 

targeted research is needed to fully understand the costs and benefits if these methodologies are 

1 U.S. Energy Information Administration, Frequently Asked Questions: How much carbon dioxide (C02) is produced 

when different fuels are burned? available at http://www.eia.gov/tools/faqs/ faq.cfm?id=73&t=ll 
Dominion Energy, Inc. Comments 

EPA Methane Mitigation Technical White Papers 

June 16,2014 

Page 13 

to become part of any future rulemaking. We encourage EPA to work with the industry and with 

equipment vendors to validate assumptions, such as costs and applicability of mitigation 

techniques which may be limited to a subset of equipment types. Further, we ask that EPA make 

full use of the data collected under the GHGRP to develop emission factors that are based on 

current industry performance and that are statistically significant. 

Compressors 

The mitigation technologies identified in the compressor white paper for use with reciprocating 

compressors are rod packing replacement, and gas recovery using either recovery for compressor 

fuel or a facility vapor recovery unit (VRU). The technologies identified for centrifugal 

compressors are the use of dry seals or the use of emissions controls (flares or gas recovery) for 

those systems using wet seals. In EPA's Petroleum and Natural Gas Systems 2012 Data 

Summary (pg. 13) the primary source of process emissions from compressors are identified as 

leaks in rod packing (reciprocating compressors), emissions from wet or dry seals (centrifugal 

compressors), emissions from blowdown vents, and emissions from isolation valve leakage. The 

source of emissions may vary based on the mode of operation that the compressor is in. A 

compressor in operating mode may have different emissions from a compressor in a shutdown 

depressurized mode. Because the emissions are from seal leakage, even compressors of the same 

manufacture can have different emissions based on the quality of the compressor seals. 

Emissions can be mitigated through rigorous maintenance practices and leak surveys, routing 

emissions to a flare, or capturing emissions. 

We agree that compressors of the same manufacture can have different emissions based on the 

quality of compressor seals. Further, it is our experience that the use of low emissions packing 

(LEP) compressor seal types does not necessarily result in decreased emissions. In 2010, we 

started a side-by-side comparison of a LEP versus conventional packing at four compressor 

stations. LEP and conventional packing were installed at the same time on two "sister" 

compressor units at each station. Measurements were taken optimally once a day when the 

system was pressurized using an orifice meter custom designed specifically to measure packing 

leaks. These measurements were then recorded by the operator. Measurements are continuing at 

two of the facilities and were discontinued at the other two locations due to resource constraints. 

Measurements are summarized in Table 1 and show emissions in both operating and nonoperating pressurized modes. 
Dominion Energy, Inc. Comments 

EPA Methane Mitigation Technical White Papers 

June 16, 2014 

Page 14 

Years 

Data 

Station Collected 

Station 

#4 3 

Average 

Table 1. 

Packin 

when 

The measurement system used was the best available at the time, but was possibly less than ideal 

used to measure a dual-phase gas stream containing oil mist which may have been present 

when some of these measurements were made. The gas stream was also at a low pressure which 

further complicated accurate measurement. However, based on the several hundred 

measurements made over the course of the study, we could only conclude that the performance 

of the LEP versus conventional packing does not conclusively show that LEP provides a superior 

performance over conventional packing. Taken at face value, the data collected would indicate 

that there is no consistent difference in performance. LEP may be useful in some applications, 

but clearly more research is needed to identify what circumstances indicate the use of LEP as a 

reduction technology. 
Dominion Energy, Inc.Comments 

EPA Methane Mitigation Technical White Papers 

June 16, 2014 

Page 15 

Changing compressor rod packing at a set interval is also discussed as a means of reducing 

methane emissions. We support this approach provided the operating company is allowed the 

flexibility to establish a packing replacement interval that coordinated with regular scheduled 

maintenance. The use of condition-based replacement would require monitoring of the packing 

vent and we are not aware of a proven monitoring methodology for this purpose, as discussed 

above, The desired outcome of a rod packing replacement protocol is to prevent methane 

emissions to the environment, but the frequency of replacement must consider the blow down 

emissions that occur each time the packing is replaced. We encourage the development of 

reliable, cost effective leak detection technologies that would support the the use of conditionbased maintenance practices in the future where packing is monitored and replaced when it starts 

to fail is preferred over changing packing at a set interval The use of a robust predictive 

maintenance program would allows the operator to monitor the unit and change packing when it 

is starting to fail but the operator must be able to reliably monitor the rod packing vent to be able 

to use this approach. 

The compressor white paper further discusses the use of dry seal centrifugal compressors and 

specifically asks if the there are situations where new wet seal centrifugal compressors are being 

installed in the field. We have not installed wet seal compressors for more than twenty years and 

do not anticipate a need for doing so. 

Pneumatics 

It is our experience that the use of high- bleed natural gas driven pneumatic controllers is limited 

to applications that require very high reliability and low response times, such as emergency 

shutoff valves on main lines that must activate in emergency situations. In remote areas where 

electric power is not available, low-bleed pneumatics are required. Based on the emissions 

expected from pneumatics and in consideration of the design requirements to meet performance 

criteria for safe operation, further policies and regulatory requirements for pneumatic controllers 

do not appear to be warranted beyond those already found in the New Source Performance 

Standards for the Oil and Natural Gas Sector (40 C.F.R. Part 60 Subpart 0000). 

Leaks 

One aspect of leak mitigation processes that has become apparent through the results of recent 

studies is that the majority of methane emissions result from a few leaks.2 This consistent 

finding is critical to the development of cost-effective leak mitigation processes. A Directed 

Inspection and Maintenance (DI&M) program begins with a baseline survey to identify and 

quantify leaks. Repairs that are cost-effective to fix are then made to the leaking components. 

Subsequent surveys are based on data from previous surveys, allowing operators to concentrate 

on the components that are most likely to leak and are profitable to repair. Baseline surveys of 

2 

T. 

A.R. 

Allen, 

Brandt, et al., Methane Leaks from North American Natural Gas Systems, Science, vol. 343 (Feb.l4, 2014); David 

the National 

et al.,Measurements 

Academy 

of Methane Emissions at Natural Gas Production Sites in the United States, Proceedings of 

of Sciences of the United States of America (PNAS), vol. 110, 17768-17773 (2013). 
Dominion Energy, Inc. Comments 

EPA Methane Mitigation Technical White Papers 

June 16,2014 

Page 16 

Natural Gas STAR partners' transmission compressor stations found that the majority of fugitive 

methane emissions are from a relatively small number ofleaking components.3 A prescriptive 

Leak Detection and Repair (LDAR) program, on the other hand, requires a full survey of all 

potential leak points at a set frequency without regard to leak history or rate. This universal 

approach along with the accompanying recordkeeping requirements makes LDAR less cost- and 

resource-effective. We believe that a better use of resources is to build an inventory of"leakers" 

that can be consistently monitored and repaired rather than to periodically recreate an inventory 

of"non-leakers". Each company has a unique equipment list that is reflected in the age, service, 

and maintenance history that can be used to create a DI&M program that is most effective and 

efficient for their systems. Further, each company has a unique operating philosophy that is 

reflected in their strategic use of assets. For example, some companies have operated assets that 

have been in place for many decades in the Appalachian basin, but with the recent shale plays in 

this area there is a need to operate assets for a few years as wells are developed in an area and 

then relocate to meet demand in other locations. This shift in asset usage was recognized by 

EPA when it amended the Subpart 0000 requirements to allow re-evaluation of storage tank 

emissions at well sites, so that control equipment could be utilized where it is most beneficial. 

The Leaks White Paper cites the ICF Study4 conclusion that LDAR is inexpensive. We suggest 

that the expense of implementation of a comprehensive LDAR program has been underestimated 

and is an unnecessary cost when similar results can be achieved using a robust DI&M program 

that is designed specifically for the operation it is intended to benefit. This is particularly true 

considering unnecessary monitoring in remote locations that have low leak potential. 

Conclusion 

In summary, we ask that this process fully consider the role of natural gas in the nation's energy 

future and encourage EPA to develop more accurate and current emissions estimates for sources 

in the natural gas industry that reflect current technologies and practices. Specific mitigation 

practices for leak detection and repair should be based on cost-effective DI&M that has been 

shown through the Natural Gas STAR program to be successful in decreasing leaks. The design 

and use of pneumatic devices has changed and continues to change as companies comply with 

We 

the New Source Performance Standards that specify the use of low-bleed and no-bleed devices. 

have shared our experience with LEP for mitigation of leaks around compressor rod packing 

and ask that EPA consider alternative practices for compressors, namely the use of conditionbased maintenance programs. 

Much work is currently underway that will inform our understanding of methane emissions and 

potential mitigation practices. As EPA is aware, some of the work that has been accomplished to 

3 

Compressor 

U.S.Environmental Protection Agency Natural Gas STAR Partners, Directed Inspection and Maintenance at 

Stations. EPA 430-B-03-008 (October 2003). 

4 

Oil 

ICF InternationaL. 2014. Economic Analysis of Methane Emission Reduction Opportunities in the U.S. Onshore 

and Natural Gas Industries. ICF International (Prepared for the Environmental Defense Fund). March 2014. 
Dominion Energy, Inc.Comments 

EPA Methane Mitigation Technical White Papers 

June 16, 2014 

Page 17 

date, and which forms the basis of the technical white papers, is based in part on work that was 

conducted some twenty years ago and which may not reflect current practice. We applaud 

EPA's efforts to better understand the portions of this work that are appropriate to consider 

moving forward and which need to be re-evaluated based on the more recent GHGRP 

information. We encourage a coordinated effort to develop flexible and effective mitigation 

policies that will allow the larger environmental benefits of natural gas as a clean and abundant 

domestic energy source to be realized. As discussed in the recently issued White House Climate 

Action Plan: Strategy to Reduce Methane Emissions, the need for a sound understanding of 

methane emissions from the natural gas industry is critical to ensuring that the benefits of natural 

gas are attained. We are a partner in the natural gas transmission and storage study of the NGOindustry cooperative research initiative sponsored by the Environmental Defense Fund and 

support these efforts to close the gaps in our understanding of methane emissions and to develop 

cost-effective emission mitigation policies. 

In closing, we again express our appreciation for the opportunity to comment and trust that the 

actions that EPA will take as a result of this evaluation and the comments received will reflect a 

clear and science-based approach. We hope that the comments provided will be useful in 

furthering this process. If you have any questions, please call me at 804-273-3467 or Roberta 

Gellner at 804-464-5961 (roberta.j.gellner@dom.com). 

Sincerely, 

Pamela F. Faggert