June 13, 2014 

Roberto Morales 

U.S. Environmental Protection Agency 

Office of Air Quality Planning and Standards 

Mail Code: C404-02 

109 T.W. Alexander Drive 

Research Triangle Park, NC 27711 

Re: Williams' Response and Comments to 

Methane I VOC Emissions and Mitigation Techniques in 

Report for Oil and Natural Gas Sector Pneumatic Devices, Review Panel, April 2014 

U.S EPA Office of Air Quality Planning and Standards {OAQPS) 

Dear Mr. Morales: 

The Williams Companies, Inc. (Williams) is submitting this correspondence to the United States 

Environmental Protection Agency (EPA) regarding methane and volatile organic compound emissions 

and mitigation techniques for pneumatic devices in EPA's, Report for Oil and Natural Gas Sector 

Pneumatic Devices, Review Panel, April 2014. 

In April 2014, EPA solicited technical comments and additional information from reviewers on five white 

papers covering methane and volatile organic compounds (VOCs) emissions from compressors, 

hydraulically-fractured wells, leaks, liquids unloading, and pneumatic devices. Williams' response for 

pneumatic devices is presented in this letter; a separate letter has been submitted to EPA for 

compressors. 

Williams reports greenhouse gas (GHG) emissions for 60 natural gas transmission, 48 gathering, 16 

natural gas processing, 1 petrochemical, and 2 underground storage facilities across the Unites States. 

These, and other smaller Williams' facilities that are currently below reporting thresholds, could be 

impacted by future EPA rulemaking on methane and VOC reductions. Williams has demonstrated, and 

continues to demonstrate, its commitment and cooperation toward reducing GHG emissions by 

identifying and prioritizing GHG sources, implementing GHG monitoring programs, and working with 

industry groups such as Interstate Natural Gas Association of America (INGAA), Gas Processors 

Association, and the American Petroleum Institute (API). Williams recognizes the importance of this 

issue and shares EPA and the Administration's intention to reduce these emissions. In order for that 

effort to achieve our mutual objectives, a strong, science-based approach must be applied and sufficient 

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presented below. 

WILLIAMS' RESPONSE TO EPA CHARGE QUESTIONS 

Question 1: 

Did this paper appropriately characterize the different studies and data sources that quantify emissions 

from pneumatic controllers and pneumatic pumps in the oil and gas sector? 

Answer: 

There are additional and ongoing investigations and studies based on information learned from industry 

trade organizations. The additional information in these studies is needed due to the low number and 

age of the current referenced studies on pneumatic devices, and the conflicting and poorly understood 

data contained in the current reports. 

Question 2: 

Please discuss explanations for the wide range of emission rates that have been observed in direct 

measurement studies of pneumatic controller emissions (e.g.J Allen et ai.J 2013 and Prasino 2013}. Are 

these differences driven purely by the design of the monitored controllers or are there operational 

characteristicsJ such as supply pressureJ that play a crucial role in determining emissions? 

Answer: 

While significant differences may be due to differences in manufacturer design and ongoing equipment 

maintenance procedures, other factors may also provide significant differences in monitored emission 

rates. As mentioned in the studies and herein, the true nature of the devices studied (intermittent, low 

bleed, etc.) was taken from information provided by field staff and may not have been properly 

characterized for the studies. In addition, there are wide variations in the actual conditions these 

pneumatic devices may be experiencing under field conditions. Differences in field gas quality, and 

especially the pressures that these devices experience, are significantly different across the country. 

Also, there may be significant differences in monitored emissions due to different staff involved, 

variations in sampling equipment, monitoring protocols, equipment calibration and monitoring 

techniques. Periodic monitoring and proper maintenance and cleaning of pneumatic devices may be 

useful in ensuring that these devices have low emissions rates. 

Question 3: 

Did this paper capture the full range of technologies available to reduce emissions from pneumatic 

controllers and pneumatic pumps oil and gas facilities? 

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Answer: 

The White Paper appears to capture the issues associated with these various techniques. Williams 

currently has no experience with zero bleed controllers due to the nature of our operations. Low bleed 

controllers have been the standard pneumatic device installed in our operations in recent years, except 

where a high bleed pneumatic controller may be needed due to process or safety/reliability concerns. 

We believe low bleed controllers to be generally reliable and cost-effective. The use of instrument air at 

locations where on-site electric power is available has also been the standard, except where a 

pneumatic controller may be needed due to process or safety/reliability concerns. Electric controllers 

are also being investigated where on-site electric power is available in non-critical applications due to 

reliability and safety concerns. 

Question 5: 

Please comment on the prevalence of the different emission control technologies and the different types 

of pneumatics in the field. What particular activities require high bleed pneumatic controllers and how 

prevalent are they in the field? 

Answer: 

High bleed pneumatic devices are typically found at older field locations, and in applications that 

demand a very high degree of reliability such as the inlet of a compressor station or gas plant where 

they may be used to control emergency valves or isolation block valves. It is important that high bleed 

devices continue to be used in these circumstances, since low bleed devices cannot provide fast enough 

actuation response times or sufficient air to actuate the large block I isolation valves. 

Question 6: 

What are the barriers to installing instrument air systems for converting natural gas-driven pneumatic 

pumps and pneumatic controllers to air-driven pumps and controllers? 

Answer: 

Typically, the availability of on-site electric power is needed for this type of conversion. Many 

compressor stations are in remote locations, away from an electrical power grid, making the conversion 

to instrument air impractical or very expensive. 

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concerns is required. 

Question 8: 

Did this paper correctly characterize the limitations of electric-powered pneumatic controllers and 

pneumatic pumps? Are these electric devices applicable to a broader range of the oil and gas sector than 

this paper suggests? 

Answer: 

Williams believes this White Paper has generally characterized the use of pneumatic controllers and 

pumps correctly. These devices, including pumps, are being used in the field in greater numbers 

wherever a reliable source of electric power (including solar) can provide for their reliable operation, 

and where the particular process allows for their use. 

Question 9: 

Are there ongoing or planned studies that will substantially improve the current understanding of VOC 

and methane emissions from pneumatic controllers and pneumatic pumps and available techniques for 

increased product recovery and emissions reductions? 

Answer: 

Yes, additional studies are currently underway, based on information learned from industry trade 

organizations. In addition, manufacturers of these devices are being pressed to also provide additional 

data regarding the operation and characterization of these devices and their associated emissions under 

varying operating conditions and pressures. 

Williams believes that EPA's consideration of the above response and comments, and input from others 

in the natural gas industry, will help the Agency better understand options for cost-effectively reducing 

methane emissions. We believe that some data gaps still remain, and that filling these gaps with 

additional measurement data is necessary before EPA develops best practices, voluntary actions, and I 

or regulations regarding methane reductions. 

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Glen Jase 

Director of Environmental Services 

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