# Attachment W

Pneumatic Devices

Environmental Defense Fund

Ramón Alvarez, Robert Harriss, David Lyon

### Oil and Natural Gas Sector Pneumatic Devices

Peer Review Responses of Environmental Defense Fund

June 16, 2014

I. E XECUTIVE 

### S UMMARY

• Pneumatic devices are, collectively, an important s ource of methane and other harmful pollutants. Pneumatic controllers and pneumatic pumps represent one of the largest sources of emissions of methane and other h armful pollutants within the oil and natural gas sector. EPA’s most recent Annual Inven tory indicates that pneumatic devices in upstream petroleum and natural gas systems accou nt for over 1 million metric tons of methane emissions per year. Recent studies confirm that these devices can individually have very high emissions, in some cases much higher than the average emission factors

used for official emissions inventories. In additi on, some recent literature suggests that the population of pneumatic controllers in the prod uction and gathering segments is greater than EPA currently assumes on the basis of well counts.

• Emissions from individual pneumatic devices are hig hly variable. Field research has also consistently indicated that there is wide vari ability in the emission rates of individual pneumatic devices. This variability demonstrates b oth the significant potential to reduce emissions by replacing or repairing the highest-emi tting devices, as well as the role of good maintenance and sound facility design in preve nting excess emissions.

• Replacement of high-bleed pneumatic controllers wit h low-bleed devices is a highly

cost-effective emission control measure. Studies have consistently found that replacing high-emitting pneumatic controllers with low-bleed models, or devices powered by instrument air or electricity, where feasible, avoi ds significant emissions and frequently yields an attractive rate of return for owners and operators. Experience with large-scale replacements of pneumatic controllers in the Denver -Julesberg basin indicates that such replacements are broadly feasible and that there ar e rarely significant operational or safety constraints that preclude such replacements.

• Improperly maintained pneumatic controllers may rep resent an important emission reduction opportunity. Maintenance problems or malfunctions of otherwise l owemitting devices can be cost-effectively detected a nd resolved as part of a comprehensive leak detection and repair (LDAR) program.

• Instrument air and electric-powered devices may be more broadly available than the White Paper indicates. Below, we present evidence that a significantly hig her proportion of oil and gas production facilities may have access to grid power than is typically assumed. In addition, the use of solar-p owered chemical injection pumps is now common operating practice in many regions of th e country.E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

2 

### II. E MISSIONS FROM 

### P NEUMATIC 

### C ONTROLLERS AND 

### P UMPS

Pneumatic controllers and pumps are ubiquitous in t he U.S. oil and gas sector, and collectively represent one of the industry’s larges t source of methane and other harmful air pollutants. According to EPA’s Annual Inventory, w hich reflects the most authoritative national census of these devices, there were approximately 9 77,000 pneumatic controllers in use in the

United States in 2012. Total methane emission from these controllers has been estimated to be over 1 million metric tons, which is approximately 13% of all methane emissions from the oil and gas sector. 1 Companies reporting under EPA’s Greenhouse Gas Re porting Program, which applies only to a subset of oil and gas facilities that meet a certain emission threshold, reported similarly high emissions of over 870,000 metric ton s in 2012. And ICF’s 2014 cost curve study,

which is based on a modified version of the Annual Inventory, found that high-bleed pneumatic

controllers alone will account for about 28 Bcf of methane emissions in 2018, equivalent to approximately 530,000 metric tons of methane. Cons istent with the Annual Inventory, ICF also found that glycol pumps and chemical injection pump s are a large source of methane, with projected emissions of 11.5 and 5.9 Bcf in 2018, re spectively. 2

Below, we respond to EPA’s charge questions and sup plement the analysis in the White Paper by presenting recent information on emission factors, activity factors, and the distribution of emissions for pneumatic controllers and pumps. As the discussion that follows indicates, recent research is providing a more complete pictur e of the nature and scale of emissions from these devices. This research supports the widely a ccepted view that pneumatic devices are one of the largest and most widespread sources of avoid able emissions in the U.S. oil and gas sector.



### A. Pneumatic Controllers

In this section, we present additional information on average emission factors for pneumatic controllers and pneumatic pumps; activity factors for pneumatic controllers; and variability in emission rates among pneumatic contr ollers and pneumatic pumps.

1. Emission Factors (Questions 1, 2)

The Gas Research Institute (GRI) study is the basis for current EPA estimates of pneumatic controller emissions in the Annual Invent ory. The GRI measurements can serve as a useful benchmark for comparison purposes. However, due to the age of the GRI measurements, more recent measurement efforts are providing addit ional valuable insight into emissions from pneumatic controllers.

1 EPA, Oil and Natural Gas Sector Pneumatic Devices at 15, 18 (Apr. 2014) (“White Paper”) (summing net CH 4 emissions and total controller counts from the prod uction, transmission, and storage segments).

2 These emissions are equivalent to approximately 21 7,000 and 112,000 metric tons of methane, respectiv ely. ICF International, Economic Analysis of Methane Emissio n Reduction Opportunities in the U.S. Onshore Oil a nd Natural Gas Industries 3-7 (Mar. 2014) [hereinafter “ICF Cost Curve Report”], available at http://www.edf.org/sites/default/files/methane_ cos t_curve_report.pdf.E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

3 The Allen et al. 3 and Prasino studies 4 provide recent and robust data sets for pneumatic controller emissions. As the White Paper notes, t he Allen study reports results of emission measurements for 305 pneumatic controllers, describ ed as a mix of low-bleed and intermittent devices, with average emissions of 10.5 ± 2.0 scf/h methane. The White Paper correctly characterizes the average emission rates that were separately estimated for low-bleed and intermittent controllers, both of which were signif icantly higher than the values reflected in the Annual Inventory.

The Prasino paper reports similar results to Allen et al; however, these results may not be representative because the study focused on high bl eed devices in a single production area in Canada. Table 2-9 of the White Paper accurately pr esents the results in the Prasino report, but we note that the emission factors presented in the Table appear to represent whole gas and we recommend that this be stated explicitly in the Tab le to avoid confusion. The Prasino report also presents average bleed rates for several common pne umatic device types used for pressure and liquid level control, ranging from 0.5 to 14.8 scf/ h whole gas. A potential limitation of the Prasino study is that the instrument that was used to quantify emissions creates back pressure on the vent line, and thus, may frequently report fals e zero emissions. 5

The City of Fort Worth Air Quality Study (“Fort Wor th Study”) 6 includes a large set of pneumatics measurements made in 2010-2011 that are not considered in the White Paper. The Fort Worth Study states that pneumatic valve contro llers were the most frequent emission sources encountered at well pads and compressor sta tions. 7 The reported emissions from 480 pneumatic controllers are presented in Appendix 3-B of the Fort Worth Study. We have extracted these results and provided them in an att ached spreadsheet. 8 Briefly, we identified pneumatic controllers in Appendix 3-B if: 1) a sour ce's classification under the equipment type was labeled "PLLC," "PLC," "LLCB," "LLC," or "Other "; and 2) the component description included the terms "PVCB" (pneumatic valve control box), "LLCB" (liquid level control box), "PLLC" (pneumatic liquid level controller), or "PLC " (pneumatic level controller). A total of 480 reported measurements met these criteria. Some of these components may be misclassified as pneumatic controllers using this approach; we ha ve highlighted approximately 10 such likely misclassifications in the spreadsheet. We did not make any further reclassification since it required subjective judgment; however, we do not be lieve that the small number of potential misclassifications would significantly affect our a nalysis of the study.

3 David T. Allen et al., Measurements of methane emissions at natura l gas production sites in the United States, Proceedings of the National Academy of Sciences (Oc t. 29, 2013).

4 The Prasino Group, Determining bleed rates for pneumatic devices in Br itish Columbia; Final Report (Dec. 18, 2013).

5 Id., at 9 and 21.

6 ERG and Sage Environmental Consulting, LP, City of Fort Worth Natural Gas Air Quality Study, F inal Report. (July 13, 2011) [hereinafter “Fort Worth Study”], available at http://fortworthtexas.gov/gaswells/default.aspx?id= 87074.

7 Id. at 3-99.

8 Fort Worth and UT pneumatics final.xlsE NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

4 The pneumatic controller emissions reported in the Fort Worth and Allen studies are summarized in Figure 1. The Fort Worth Study emiss ions average is 34.5 scf/h of methane, which is higher than the emissions average reported by the Allen and Prasino studies. On the other hand, the Fort Worth results are very similar to Environ's 2009 emission factor for liquid level controllers (31 scfh), the predominant applic ation for the sampled pneumatics in the Fort Worth Study (see WP Table 2-11). The Fort Worth av erage emission factor is also consistent with the high-bleed emission factor that ICF derive d from Subpart W data for its 2014 study of methane reduction opportunities in the oil and gas sector. 9

One reason for the difference between the Fort Wort h and Allen results is the sampling approach. At most sites, the Allen study randomly s ampled from the controllers associated with the wells at the site. In contrast, the Fort Worth measurements were made on devices found to be emitting with an infrared camera or with a handheld hydrocarbon detector. This may explain why the Fort Worth study generally found higher mea sured emissions than the Allen study. In addition, as described in Part III of this response , the authors of the Fort Worth study observed that a number of the sampled pneumatic controllers appeared to be malfunctioning.

As shown in Figure 1B, the Allen study and Fort Wor th Study share a common feature that a small proportion of devices account for a la rge share of total emissions. In both studies, approximately 20% of the devices accounted for 70 t o 75% of the total emissions. Further, there

is wide variation in the individual emission rates measured, with a significant number of very high-emitting devices and a significant number of l ow-emitting devices. For example, approximately 40% of the controllers monitored in t he Allen study had emission rates exceeding 6 scf/h (the normal definition of a high-bleed cont roller), even though the study population contained no high-bleed controllers. At the same t ime, approximately 25% of the controllers in the Allen study had very low emissions of less than 1 scf/h. As Figure 1A shows, a similarly

wide distribution of emission rates was observed in the Fort Worth study.

9 ICF Cost Curve Report, supra note 2, at B-6 (reporting high-bleed emission factor of 320 Mcf/yr, or 36.5 scf/h).E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

5 Figure 1. Emissions measurements of pneumatic contr ollers in the city of Fort Worth Study and Allen et al.



### 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1.E-03 1.E-01 1.E+01 1.E+03Cumulative Probability



### scfh CH4 A. Distribution of pneumatic controller emissions (log scale)



### Fort Worth

Allen et al.

0 10 20 30 40 50 60 70 80 90 100

0 20 40 60 80 100% of Emissions



### % of Sites B. Cumulative distribution



### Fort Worth

Allen et al.E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

6 2. Activity Factor (Question 1)

There is uncertainty about the total number of pneu matic controllers, both in absolute terms and relative to the number of well sites, whi ch are themselves fairly well characterized. The Annual Inventory assumes a ratio of pneumatic c ontrollers to wells of roughly 1:1, and this ratio is a key driver for the total count of pneuma tic controllers in the Annual Inventory. A very similar ratio was reported in a 2012 survey by the American Petroleum Institute (API) and America’s Natural Gas Alliance (ANGA). 10

However, several recent studies have found a higher ratio of controllers to well sites, including:

• The Allen study sampled 305 devices, representing 4 1% of all the controllers at the sampled wells. Since there were 489 wells in the s tudy, the number of pneumatic controllers per well is approximately 1.5. 11

• The Environ Report summarized on Table 2-11 in the WP indicates 3 devices per natural gas well.

• A 2006 survey of producers in the Denver-Julesberg basin by the Independent Petroleum Association of the Mountain States (IPAMS) found ap proximately 3 devices per natural gas well. This survey was a critical source of inf ormation in Colorado’s recent rulemaking on emissions from high-bleed pneumatic c ontrollers, and is discussed further in Part III of this response.

Although it is difficult to draw firm conclusions f rom these studies, they do suggest that the ratio of pneumatic controllers to wells that EPA re lies upon in the Annual Inventory is a conservative one - and that the actual number of pn eumatic controllers in the production segment may be considerably higher than EPA currently assum es. In addition, ICF’s 2014 cost curve study noted that the Annual Inventory does not repo rt pneumatic controllers located at gathering and boosting stations. Based on the API/ANGA surve y, ICF estimated that approximately 23,000 pneumatic controllers associated with gather ing and boosting facilities are missing from the Annual Inventory. 12 This reinforces the inference that the Annual Inv entory assumptions regarding pneumatic controller counts are conservat ively low.

3. Future Studies (Question 9)

The University of Texas is leading a follow-on stud y to Allen et al. The follow-on study will report additional measurements of emissions fr om pneumatic controllers. A manuscript reporting on these results is expected to be submit ted for publication in a scientific journal in the

summer of 2014.

10 Terri Shires & Miriam Lev-On, Characterizing Pivotal Sources of Methane Emissions From Natural Gas

Production 27 (2012) [hereinafter “API/ANGA Study”].

11 The ratio is estimated according to the formula: 3 05/(0.41×489) = 1.5.

12 ICF Cost Curve Report, supra note 2, at B-6.E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

7 

### B. Pneumatic Pumps (Question 1)

The White Paper does not appear to take note of the pneumatic chemical injection pump

measurements in Allen et al . The Allen study sampled 62 chemical injection p umps, all located in the Gulf Coast and Midcontinent regions. Emissi on measurements were taken at these pumps using a HiFlow sampler. Some sites sampled in the Allen study had solar-powered chemical injection pumps, and therefore exhibited no pump-re lated methane emissions.

The Supplemental Information accompanying the Allen study, at S-29-S-30, reports a slightly lower emission factor for pneumatic chemic al injection pumps (12.2 scf/h) than the potential emission factor in the EPA Annual Invento ry (13.3 scf/h). The Allen study encountered significant geographical variability in emissions rates among pneumatic pumps, similar to the variability among pneumatic controll ers. The Allen study was not able to identify the cause of this variability, although several hyp otheses were tested. 13 The 2014 GHG EI reported national emissions from chemical injection pumps on a net basis, 65 Gg (Table A-141), which is in good agreement with the national estima te of Allen et al (68 Gg, 95% range of 35- 100 Gg).



### III. E FFICACY AND 

### C OST 

### -E FFECTIVENESS OF 

### M ITIGATION 

### O PTIONS



### A. Replacement or Retrofit of High-Bleed Pneumatic Con trollers (Questions 4, 5)

EPA’s White Paper correctly indicates that replacin g high-bleed pneumatic controllers

with low-bleed models is an effective control strat egy that achieves significant emission reductions and yields significant cost recovery for upstream operators. Citing Natural Gas STAR documentation and EPA’s 2011 TSD for the NSPS, the White Paper estimates that the replacement of a single high-bleed pneumatic contro ller in the production segment reduces emissions by an average of 6.65 tons per year of me thane and 1.8 tons per year of VOC. Using standard assumptions regarding the average concentr ation of methane in natural gas, and a conservative natural gas price of $4/Mcf, the White Paper estimates that these emission reductions would equate to annual savings of approx imately $1,500 per controller. 14 This conservative estimate of savings suggests that oper ators would fully recoup the cost of a pneumatic controller replacement in less than two y ears. EDF strongly agrees that pneumatic controller replacements are an effective control st rategy for methane and associated copollutants, and agrees that the assessments of cost -effectiveness presented in the White Paper are reasonable. Below, we provide additional informati on that broadly confirms the White Paper analysis and supplements the White Paper’s discussi on of the applicability of this technique.

13 Allen et al., Supplemental Information at S-30.

14 The White Paper appears to include an erroneous ca lculation of the annual savings that would result f rom replacement of pneumatic controllers in the transmi ssion segment. The savings estimate of $1,375 per controller appears to be based on an assumed emission reductio n of 6.65 tons of methane per year. However, accor ding to EPA’s 2011 TSD, a low-bleed pneumatic controller in the transmission segment reduces emissions by only 3.7 tons of methane per year. Using the assumptions in the White Paper, these emission reductions would equate to annual savings of approximately $767 per year.E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

8 1. Cost-effectiveness and efficacy of replacements.

Recent studies of pneumatic controllers, which are not fully discussed in the White Paper, support the White Paper’s conclusions regarding the cost-effectiveness of retrofitting or replacing high-bleed devices. For example, the Whi te Paper contains an incomplete discussion of ICF’s 2014 analysis of the cost-effectiveness an d efficacy of replacing high-bleed pneumatic

controllers. Based on emission factors derived fro m Subpart W data, ICF determined that an individual pneumatic controller replacement would r educe emissions by approximately 97%, and

at a negative annual cost of -$3.08/Mcf of methane – even when a ssuming a relatively high capital cost of $3,000 per device.

In addition, the Allen study supports the cost-effe ctiveness figures presented in the White Paper. As noted above, the Allen study reported a wide range of emission rates for the 305 low and intermittent-bleed controllers that were sample d. The highest-emitting 20% of pneumatic controllers sampled in the Allen study had an avera ge emission rate of 37.7 scf/h, equivalent to approximately 330 Mcf/y and similar to the emission factor of 320 Mcf/y derived by ICF for high-bleed pneumatic controllers reported under Sub part W), 15 and the lowest-emitting 20% had an average emission rate of 0.3 scf/h, equivalent t o 2.6 Mcf/y. If the average pneumatic controller from the top-emitting quintile in the Al len study were replaced with the average pneumatic controller from the lowest-emitting quint ile, the annual emissions avoided would be approximately 327 Mcf/y. At an assumed natural gas price of $4/Mcf, this would amount to $1,308 in savings per year per device, which is con sistent with the analysis presented in the White Paper.

The White Paper also appears to overlook significan t state-level experience with mandating replacement of pneumatic controllers, and analyses that have been undertaken in support of those requirements. Colorado’s Air Qual ity Control Commission (AQCC) first mandated the replacement of existing high-bleed pne umatic controllers in the Denver-Julesberg basin in 2008. In 2014, the AQCC extended this req uirement to all of the high-bleed pneumatic controllers in the state. On both occasions, the A QCC based its requirements on rigorous technical analyses of costs and benefits, which are attached here as exhibits.

Colorado’s November 2008 analysis includes detailed information on bleed rates of new liquid level and pressure controllers; capital, ins tallation and O&M costs associated with retrofits and replacements; and annual benefits of replacemen t, all based on an industry survey of pneumatic controllers in the Denver-Julesberg basin in 2006. Colorado’s analysis found that replacements of a high-bleed device would pay for i tself within seven months, on average, and

would achieve VOC emission reductions of close to 9 0%. 16 For some types of pneumatic controllers, Colorado found an average payback time of just three months, using the relatively high gas prices that prevailed in 2008.

15 ICF Cost Curve Report, supra note 2, at B-6.

16 See Colorado Department of Public Health and Environmen t, Air Pollution Control Division, Denver Metropolitan Area and North Front Range 8-Hour Ozon e State Implementation Plan, Technical Support Docu ment for Proposed Pneumatic Controller Regulation 14-15 (Nov. 2008) [“APCD 2008”].E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

9 In 2014, Colorado updated and supplemented this ana lysis. 17 Among other things, Colorado increased the costs of controller replacem ents to account for inflation; 18 assumed a very conservative natural gas price of just $3.50/M cf; and estimated state-wide emission

reductions based on the above-mentioned 2006 indust ry survey. Based on this survey, Colorado found that the average bleed rate of high-bleed con trollers was 16.8 scf/h (140 Mcf/yr), and that the average bleed rate of low-bleed controllers was 1.93 scf/h (17 Mcf/yr). Even at substantially lower gas prices, Colorado found that replacement o f high-bleed pneumatic controllers would be very cost-effective: replacement would have an annu al net cost of -$1,084 per device and an average payback period of approximately 14 months. 19

2. Evidence of significant emission reductions from re placements.

The White Paper also contains little discussion of the potential for large-scale emission reductions from widespread replacement of high-emit ting pneumatic controllers, which has been

the focus of several recent studies. ICF’s 2014 re port, for example, found that pneumatic controller replacements were not only highly cost-e ffective on an individual basis, but also represented one of the single largest emission redu ction opportunities across the entire oil and gas sector. ICF estimated that if carried out nati onwide, replacement of high-bleed pneumatic controllers would avoid nearly 25.4 billion cubic f eet of methane emissions per year in 2018 (approximately 480,000 metric tons of methane) – an d at a negative cost of -$67.4 million per

year. 20 ICF’s general conclusions regarding the efficacy of replacement are consistent with other analyses, including a 2013 report by the World Reso urces Institute that estimated that nationwide replacements of high-bleed pneumatic controllers co uld yield emission reductions of 19 million

metric tons CO 2 -e by 2019. 21 WRI identified high-bleed pneumatic replacements as one of the top three high-impact methane mitigation measures t hat could significantly reduce methane emissions from the U.S. oil and natural gas sector.

Colorado’s 2014 analysis supporting the state-wide phaseout of high-bleed pneumatic controllers also found a significant potential for emission reductions, in part because Colorado found that a large number of high-bleed devices rem ained in the state. Based on 2006 industry survey data, Colorado found that each well in the D enver-Julesberg had an average of 3.1 pneumatic controllers, and that slightly over 13% o f those controllers were high-bleed devices. Further, based on industry input, Colorado determin ed that 95% of remaining high-bleed

17 See Colorado Department of Public Health and Environmen t, Air Pollution Control Division, Prehearing Statement Exhibit SS (2014).

18 Notably, Colorado’s cost study found that a low-bl eed controller would cost approximately $1,033 with an additional $387 in one-time labor costs. This is s ubstantially lower than the costs cited in the Whit e Paper. Id.

19 Colorado Department of Public Health and Environme nt, Air Pollution Control Division, Regulatory Analysis for Proposed Revisions to Colorado Air Quality Control Commission Regulation Numbers 3, 6, and 7 (Feb. 2014).

20 For its analysis, ICF also conservatively estimate d that approximately 10% of controllers in the prod uction segment are high-bleeds, and that 90% of these coul d be replaced with low-bleed controllers. ICF assu med much lower rates of replacement in segments further down stream of production. ICF Cost Curve Report, supra note 8, at

3-15 to 3-16.

21 James Bradbury et al., Clearing the Air: Reducing Upstream Greenhouse Gas Emissions from U.S. Natural Gas Systems 28 (World Resources Institute, 2013).E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

10 controllers in the state could be retrofitted or re placed. 22 Statewide, Colorado estimated that the requirement would apply to approximately 9,400 cont rollers and would achieve total methane emission reductions of over 15,500 metric tons per year (nearly 1 billion cubic feet of methane). 23

Notably, the nationwide potential for emission redu ctions from pneumatic replacements could be much greater than the above-mentioned anal yses suggest. As noted above, several recent studies – including the Allen study and the IPAMS survey used in the Colorado analysis – indicate that the number of pneumatic controllers p er well site ranges from 1.5 to 3.1, or 50% to 200% greater than the average EPA assumes in the An nual Inventory. 24 ICF’s 2014 report also noted a 2012 survey by API and ANGA which found an average of approximately 8.6 pneumatic controllers at each gathering compressor station, o f which approximately 7% were high-bleed

controllers. These devices are not accounted for i n the Annual Inventory. 25 These studies suggest that overall emissions from high-bleed pneu matic controllers – and the potential for emission reductions through replacement or retrofit – could be much higher than the current Annual Inventory would suggest.

3. Replacement of high-bleed pneumatic devices widely applicable

Lastly, the White Paper states that operational or safety considerations may limit the applicability of replacements or retrofits of high- bleed pneumatic controllers. Such situations appear to be extremely rare, as Colorado’s experien ce requiring replacement of these controllers suggests. Colorado based its 2008 replacement requ irement in part on information from industry suggesting that nearly all high-bleed pneumatic con trollers in the Denver nonattainment area could feasibly be replaced. 26 Notwithstanding this information, Colorado allowe d owners and operators in the nonattainment area to petition for a waiver of the replacement requirement where necessary. EDF understands that Colorado has not r eceived any petitions for such waivers in the six years since this requirement took effect. This is a strong indication that replacement of highbleed pneumatic controllers could be broadly applie d.

22 This assumption was adopted from the 2008 analysis , which found that “close to 100% of the high bleed s will be converted to low/no bleeds” based on industry feedb ack from the Colorado nonattainment area. See APCD 2008, at 12. Notably, Colorado’s prediction was borne out b y subsequent experience implementing the replacemen t requirement in the Denver ozone nonattainment area. In the 2008 regulation, Colorado allowed operator s to petition for a waiver of the pneumatic controller retrofit/r eplacement requirement in situations where replacem ents or retrofits are not technically feasible or safe. ED F understands that no such petitions have been file d since that requirement took effect.

23 Colorado Department of Public Health and Environme nt, Air Pollution Control Division, supra note 17.

24 The Fort Worth study found that there were 1.3 emitting controllers per well site examined, suggesting that the

ratio of total pneumatic controllers to wells was higher.

25 ICF Cost Curve Report, supra note 2, at B-6. Based on the API/ANGA survey, ICF estimated that there are approximately 23,000 pneumatic controllers in the g athering and boosting segment that are not accounte d for in the Annual Inventory. Notably, the API/ANGA survey als o found an average of approximately 0.99 pneumatic controllers per well.

26 See APCD 2008, supra note 16.E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

11 

### B. Enhanced Maintenance of High-Emitting Controllers ( Question 3)

In addition to replacing or retrofitting inherently high-emitting pneumatic controllers, proper maintenance of existing devices is essential to ensuring continued emission reduction over time. Application of regular leak detection a nd repair (LDAR) techniques to pneumatic controllers and pumps, especially as part of a comp rehensive LDAR program applied to all components of an oil and gas facility, is a cost-ef fective way to identify maintenance issues and malfunctions in pneumatic devices.

The White Paper appropriately cites Natural Gas STA R documentation in discussing potential emission reductions from enhanced mainten ance, and common causes of upsets or malfunctions at pneumatic controllers. Additional literature, which is not cited to in the White Paper, further indicates that poor maintenance and malfunctions are an important cause of high emissions from pneumatic controllers. For example, the Fort Worth Study examined emissions from 489 intermittent pneumatic controllers, using infrared cameras, Method 21, and a HiFlow sampler for quantification. The study found that m any of these controllers were emitting constantly and at very high rates, even though thes e devices were used to operate separator dump valves and were not designed to emit in between act uations. Average emission rates for the controllers in the Fort Worth study were 34.5 scf/h (302 Mcf/yr), or 6 tons per year of total organic compounds (TOC) – a rate that approaches th e average emissions of a high-bleed pneumatic controller. Over 50% of the controllers emitted more than 16 scf/h (140 Mcf).

According to the study authors, these emissions wer e frequently due to malfunctioning or

failed controllers:

Pneumatic Valve Controllers were the most frequent emission sources encountered at well pads and compressor stations . These controllers use pressurized natural gas to actuate separator unload ing valves. Under normal operation a pneumatic valve controller is designed to release a small amount of natural gas to the atmosphere during each unloading event. Due to contaminants in the natural gas stream, however, these controlle rs eventually fail (often within six months of installation) and begin leaking natur al gas continually. The emissions from the 489 failed pneumatic valve contr ollers detected by the point

source team result in a combined TOC emission rate of 3,003 tons per year. 27

The Prasino study of pneumatic controller emissions in British Columbia also noted the potential for maintenance issues to lead to abnorma lly high bleed rates. 28 As noted above, the Prasino study – like the Fort Worth study and UT-Au stin studies - found significant variability in the emission rates of pneumatic controllers. In pa rticular, some pneumatic controllers that were nominally rated as “low bleed” models by manufactur ers exhibited emission rates much higher than 6 scf/h in the field. Although the researcher s did not identify a cause for these unexpectedly

27 Fort Worth Study, supra note 5, at 3-99 to 3-100 (emphasis added).

28 Prasino, supra note 3, at 19 (“Certain controllers can have abnor mally high bleed rates due to operations and maintenance; however, these bleed rates are represe ntative of real world conditions and therefore were included in the analysis.”).E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

12 high emission rates, the results are consistent wit h the observation that maintenance and operational issues can lead to high emissions.

As the Fort Worth Study suggests, the same methods used for leak detection at valves, connectors, and other leaking components at oil and gas facilities can be used to spot significant malfunctions at pneumatic controllers. Moreover, i f a comprehensive LDAR program is already being implemented at a facility, the marginal cost of extending that program to pneumatic controllers would be very modest. Well production sites typically have a small number of controllers per well. 29 More complex facilities such as gathering and boo sting facilities, and gas processing plants, may have eight to nine pneumatic controllers per site. 30 In either case, however, pneumatic controllers would represent only a small fraction of the total number of components that would usually be monitored for leak s under a LDAR program. In the Fort Worth study, for example, the well production sites studied had an average of about 1,500 components each. This is consistent with the Subpa rt OOOO technical documentation, which assumed that an intermediate-size well production f acility with five wellheads would have approximately 1,200 components amenable to LDAR. 31



### C. Conversion to Instrument Air or Electric Power (Que stion 8)

The White Paper correctly notes that conversion of pneumatic controllers and pumps to compressed air, or to electrically powered devices, can eliminate emissions. However, the White Paper also notes that these strategies require eith er access to electric distribution infrastructure, or the use of solar-powered devices. Below, we off er additional information on the availability and cost of these technologies.

1. Grid power potentially available at many production facilities.

In the 2012 NSPS rulemaking, EPA assumed that grid electricity is not available at oil and gas facilities other than natural gas processin g plants, and cited this as a key rationale for declining to require the use of no-bleed pneumatic controllers at such facilities. However, there is anecdotal evidence indicating that access to gri d power at oil and gas production facilities may be more prevalent than is widely believed. One rep ort commissioned by the North Dakota Transmission Authority in October 2012 – which was intended to forecast electric load requirements associated with growing oil and gas pr oduction in the Williston Basin – found that approximately 80% of 1,087 existing oil wells surve yed were tied to the electrical grid, and that 95% would be connected to the grid in 10 years. 32

29 As noted above, the Annual Inventory assumes appro ximately one controller per well, whereas recent fi eld studies have found an average of 1.3 to 3.1 controllers per well.

30 See API/ANGA supra note 9, at 26.

31 EPA, Oil and Natural Gas Sector: Standards of Performanc e for Crude Oil and Natural Gas Production, Transmission, and Distribution, Background Suppleme ntal Technical Support Document for the Final New S ource Performance Standards C-3 (Apr. 2012).

32 Kadrmas, Lee & Jackson, Inc., Power Forecast 2012: Williston Basin Oil and Gas Re lated Electrical Load

Growth Forecast 15 (Oct. 2012), available at http://www.nd.gov/ndic/ic-press/Power2012.pdf.E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

13 Similarly, an oil and gas producer in Oklahoma rece ntly indicated at its annual meeting that only one in ten of its wells rely on generator s for on-site power. 33 Recent press reports from

Oklahoma have also indicated that rural electric co operatives are rapidly expanding generation and transmission capacity to serve growing loads fr om oil and gas production sites. 34 Lastly, the ICF study assumed that approximately 50% of pneumat ic glycol pumps could be replaced with electric pumps due to widespread access to grid ele ctricity. 35 All of these sources suggest EPA

should undertake closer examination of the extent t o which both new and existing oil and gas production facilities have access to grid power and can feasibly implement no-bleed alternatives to pneumatic controllers and pumps.

2. Cost and availability of solar-powered pump technol ogies.

Based on firsthand observations of oil and gas faci lities, EDF also understands that the use of solar-powered chemical injection pumps is no w widespread in key oil and gas producing regions such as the Eagle Ford basin and the Marcel lus Shale. There are also a number of major vendors of solar-powered chemical injection pumps, which is a further indication that solarpowered pump technology is commercially available a nd broadly used.

As further indication of the cost-effectiveness and widespread availability of this approach, one of the Natural Gas STAR partner compa nies reported as early as 2010 that it was replacing all chemical injection pumps in its Barne tt Shale operations with solar-powered models. As of 2010, the company had replaced 140 p umps at a cost of $188,300 (approximately $1,300 per pump), and was avoiding over 8 million c ubic feet per year in natural gas losses as a result. At this rate of savings, the company estim ated it would recover its initial investment in slightly less than six years at a gas price of $4/M cf, and slightly less than five years at a gas pric e of $5/Mcf. 36



### IV. E XHIBITS

1. EDF Analysis of Pneumatic Controller Emissions Data from Fort Worth Study and Allen et al., Fort Worth UT Pneumatics.xlsx (May 2014)

2. Colorado Department of Public Health and Environmen t, Air Pollution Control Division, Denver Metropolitan Area and North Front Range 8-Ho ur Ozone State Implementation Plan: Technical Support Document for Proposed Pneum atic Controller Regulation (Draft, Nov. 2008).

33 Jay F. Marks, Natural gas bringing cheaper electricity to Oklahom a oil play, NewsOK (July 12, 2013) (Reporting that the CEO of SandRidge Energy Inc., the leading producer in the Mississippian oil play, stated, “We have very few wells on generators at this point . . . . In th is part of the world, we didn't have a full electri cal distribution system. The company was very aggressive and stepped out and built these lines. From about a year and a half ago, we've taken the number of generators down from abou t 35 percent to about 11 percent.”)

34 Victoria A. Rocha, Oklahoma Co-ops Face Oil, Gas Boom, (Sept. 25, 2012) (reporting on efforts by four Oklahoma co-ops to keep up with growing electricity demand from remote oil and gas production faciliti es).

35 ICF Cost Curve Report, supra note 2, at 3-16.

36 Zach Schaffer, Terry Chapman & Don Bredy, Renewable Power Applications at Natural Gas Well Si tes 10 (Chesapeake Energy, Nov. 2010).E NVIRONMENTAL D EFENSE F UND • J UNE 16, 2014

14 3. Colorado Department of Public Health and Environmen t, Air Pollution Control Division, Pneumatic Analysis, Prehearing Statement Exhibit SS (Date Unknown)

4. Colorado Department of Public Health and Environmen t, Air Pollution Control Division, Regulatory Analysis for Proposed Revisions to Color ado Air Quality Control Commission Regulation Numbers 3, 6, and 7 (Feb. 2014).