### EPA RESPONSE TO Summary of Interagency Working Comments on Draft Language under EO12866/13563 Interagency Review. S ubject to Further Policy Review.

1 Environmental Protection Agency (EPA): Proposed Rule

Oil and Natural Gas Sector: Emission Standards for New and Modified Sources

RIN 2060

- A S30

General Comments :

1. Reviewer recommends providing additional discussion on why it is necessary to regulate methane in the areas where controls for VOCs are already providing the reduction.

EPA RESPONSE: We believe the preamble fully supports across th e category regulation of VOC and

methane. “ Based on the EPA’s analysis (see section VIII), we believe it is i mportant to regulate methane from the oil and gas sources already regulated for VOC emissions to provide more consistency across the category, and that the best system of emission reduction (BSER) for methane for all these sources is the same as the BSER f or VOC. Accordingly, the current VOC standards also reflect the BSER for methane reduction for the same emission sources. In addition, with respect to equipment used category

- wide of which only a subset of those equipment are covered under the NSPS VOC sta ndards (i.e., pneumatic controllers and compressors located other than at well sites), EPA’s analysis shows that the BSER for reducing VOC from the remaining unregulated equipment to be the same as the BSER for those currently regulated. The EPA is theref ore proposing to extend the current VOC standards for these equipment to the remaining unregulated equipment. ”

2. Reviewer recommends considering the overall economic impact on stripper wells and ensuring that any proposed NSPS requirements are not overly burdensome such that stripper wells would need to be shut down based on any single or combination of proposed requirements

.

EPA RESPONSE: Please see additional discussion in the preamble. “ We do not intend to subject low production wells ( i.e. , those wit h an average daily production of 15 barrel equivalents or less) to the standards for well completion . It is our understanding that drilling of a low production well is infrequent and in most instances unintentional, but production may nevertheless proceed due to economic reasons. While we have learned that a daily average of 15 barrel equivalents is representative of low production wells, we solicit comment on the appropriateness of this threshold for applying the standards for well completions. We further solicit comment on the air emissions associated with low production wells, and the characteristics of low production wells that may inform owners or operators and enforcement personnel in advance of production whether such a well would be a low production well, so we may evaluate the feasibility of an exemption from well completion standards .”

### EPA RESPONSE TO Summary of Interagency Working Comments on Draft Language under EO12866/13563 Interagency Review. S ubject to Further Policy Review.

2 Well Completions:

1. R eviewer recommends considering other factors such as geographic location, gas production and GOR of nearby wells, length of hydraulic fracturin g, and well depth to

sub

- categorize units to maximize cost

- effectiveness and not unduly burden units.

EPA RESPONSE: We are taking comment on this in Section VIII.F “ We solicit comment on the types of oil wells that will not be capable of performing a REC or combusting completion emissions due to technical considerations such as low pressure or low gas content, or other physical characteristics such as location, well depth, length of hydraulic fracturing, or drilling direction (e.g., horizontal, vertical, directional).”

Further, w e are proposing a GOR threshold of 300 scf/barrel for applicability of well completion requirements. We understand that it is important for operators to know the affected facility status of a well completion prior to commencement of the completion operation and are soliciting comment whether GOR of nearby wells is a reliable indicator that could be used by operators.

2. Reviewer recommends not regulating oil wells for which gas recovers would be too small (e.g., yielding less than 30 tons).

EPA RESPONSE: We are taking comment on this in Section VIII.F

. Please see response to previous question. The purpose of the proposed GOR threshold is to identify and exclude wells that would have very small magnitudes of gas production and pot ential emissions.

3. Reviewer recommends considering the following thresholds:

a. p hysical characteristics of certain oil wells that make REC and/or combustion not technically feasible or economic ; b. a ll vertical oil wells as the nature of the wells make it difficult or technically infeasible to operate a two or three phase gas/liquid separator because these wells generally lack sufficient wellhead pressure or a sufficient quantity of gas; and/or

c. low pressure or low volume wells and heavy oil wells based on the GOR. Low pressure wells could be based on a threshold sales line/gathering line or a wate gradient formula.

EPA RESPONSE: We are taking comment on this in Section VIII.F

.

Pneumatic Controllers:

1. Reviewer recommends removing any recordkeeping requirements for low

- bleed or

zero

- bleed pneumatic controllers as it is unnecessary and burdensome.

### EPA RESPONSE TO Summary of Interagency Working Comments on Draft Language under EO12866/13563 Interagency Review. S ubject to Further Policy Review.

3 EPA RESPONSE: In locations other than natural gas processing plants, l ow

- bleed and zero

- bleed pneumatic

controllers are not affected facilities, and thus no recordkeeping or reporting requirements apply to this equipment. However, natural gas

- operated pneumatic controllers located at natural gas processing plants are affected facilities regardless of their bleed rate. I n such

cases, this equipment is subject to the recordkeeping and reporting requirements outlined

in §60.5420a. Such records would include justification of the need for a device with a natural gas bleed rate greater than zero.

Compressors :

1. Reviewer recommends explaining how the National Inventory based on Subpart W data was considered within the development of the proposed rule. Specifically, as the more recent data appears to provide lower emission data, how has EPA taken that into

conside ration when developing the proposed rule?

EPA RESPONSE: Detailed information on data used in the development of the proposed rule, and a discussion of data from alternative and newly available data sources, is included in the

TSD.

For most sources, emis sions and activity data from the 2014 U.S. GHG Inventory (GHGI) were used in the development of the proposed rule. While overall sector

- level emissions decreased in the 2015 GHGI compared to the 2014 GHGI (primarily due to revisions to offshore production estimates), emissions and activity data for the sources included in this proposal did not change significantly. The most recent facility

- level GHGRP data was also reviewed in the development of the proposed rule. The GHGRP data indicate higher emissions than in the GHGI for some sources and indicate lower emissions for others, as is discussed in the TSD.

As EPA continues to review new data sources, including key activity data from the GHGRP which will become available in the fall of 2015, EPA will consi der how these data may be used to update its GHG inventory estimates and analyses related to this rulemaking. EPA has for several sources updated the GHGI to use GHGRP data and will continue to do so as additional key data become available.

2. Reviewer re commends removing the requirement for vapor recovery units for wet

- seal centrifugal compressors as there are potential issues related to feasibility and safety.

EPA RESPONSE: The proposed NSPS does not require vapor recovery units for control of emissions from

wet

- seal centrifugal compressors; the rule requires 95 percent control of these emissions or routing of the emissions to a process . Under section 111, the EPA cannot dictate what

### EPA RESPONSE TO Summary of Interagency Working Comments on Draft Language under EO12866/13563 Interagency Review. S ubject to Further Policy Review.

4 type of control device is required to meet an emission standard. That decision is made by the owner or operator. The NSPS does include, however, requirements for specific types of control devices, if such devices are used to meet the emission standard (e.g., cover and closed vent system requirements and requirements for periodic monitoring). As is the case across the NSPS, a control technique is not considered BSER if technical feasibility or safety issues are a concern.

3. Reviewer recommends providing additional explanation how EPA ensured that emissi ons from rod packing leaks are separated from fugitive emissions from compressors.

EPA RESPONSE: Fugitive emissions do not include gas that is vented from a device (e.g., pneumatic controller exhaust port, reciprocating compressor rod packing) . As a re sult, fugitives seen in the rod packing area would likely not be from a fugitive emissions component since, given the structure of reciprocating compressors, it is unlikely to have valves, flanges, etc. located in the immediate area of the rod packing.

P neumatic Pumps:

1. Reviewer recommends excluding diaphragm pumps, glycol pumps, and all low volume chemical injection pumps or other pumps that are used intermittently below a fixed number of hours/year.

EPA RESPONSE: Glycol (i.e., “Kimray”) pumps are not covered by the proposed NSPS. With regard to an operating hour threshold, we would need additional data (such as emissions levels

associated with different operating times and costs ) to fully evaluate this potential o p tion.

Fugitive Emissions:

1. Reviewer recommends considering additional options besides OGI and Method 21, specifically AVO methods. The relative benefits and costs should be included within the

discussion.

EPA RESPONSE: We are requesting comment on wh ether there are other fugitive emission detection technologies that provide an equivalent or greater level of detection than OGI technology

or EPA Method 21 that should be allowed in VIII.F

.

2. Reviewer recommends providing clarification for the repair costs within the RIA and TSD for Method 21 and OGI. It is unclear why the repair costs change within OGI to the extent that they do and why they differ from Method 21.

### EPA RESPONSE TO Summary of Interagency Working Comments on Draft Language under EO12866/13563 Interagency Review. S ubject to Further Policy Review.

5 EPA RESPONSE:

Please see clarification in section VIII.G, “ While the costs for repairing components that are found to have fugitive emissions during a fugitive monitoring survey remain the same, the annual repair costs will differ based on monitoring frequency” . Section 5.4 of

th e TSD provides additional repair cost information.

3. Reviewer recommends providing clarification for why the emission reduction estimates

deviate from the Colorado source document and how it was used within the RIA.

EPA RESPONSE: The preamble states tha t information in the white paper related to the potential emission reductions from the implementation of an OGI monitoring program varied from 40 to 99 percent. The causes for this range in reduction efficiency were the frequency of surveys performed and d ifferent assumptions made by the study authors. We used engineering judgment to identify anticipated percent reduction based on frequency. We believe that 40%, 60%, and 80% are adequately representative of the reduction we would expect with increased frequ encies of survey.

4. Reviewer recommends providing additional information on the Method 21 emission

reduction information. It is unclear within the TSD how the differences between the Method 21 for 10,000 ppm leaks and Method 21 for 5,000 ppm leaks were det ermined (see Table 5

- 20 on page 98).

EPA RESPONSE: Please see clarifying text in Section VIII.G , and Section 5.4 of the TSD

. “ In our analysis, we estimated emissions reductions for annual, semiannual and quarterly options for conducting the Method 21 m onitoring at the three repair threshold levels of 500 ppm, 2,500 ppm and 10,000 ppm. The EPA Equipment Leaks Protocol document provides emissions factor data based on leak definition and monitoring frequencies primarily for the Synthetic Organic Chemical M anufacturing Industry (SOCMI) and Petroleum Refining Industry. This data was used to estimate the uncontrolled emissions (i.e., baseline emissions and the corresponding emission reduction percentages that could potentially be achieved for each of the leak definitions (500 ppm, 2,500 ppm, 10,000 ppm) and monitoring frequencies (annual, semiannual, quarterly). Using this information we calculated an expected emissions reduction percentage for each of the combinations of monitoring f requency and repair thresho ld.”

5. Reviewer recommends providing additional discussion on whether observed leak rate would change over successive surveys, and if so, account for that within the analysis.

EPA RESPONSE: EPA will provide this additional context in the technical support document

.

### EPA RESPONSE TO Summary of Interagency Working Comments on Draft Language under EO12866/13563 Interagency Review. S ubject to Further Policy Review.

6 6. Reviewer recommends phasing in fugitive emissions requirements with larger sources in the first year and smaller sources in the following years. Small firs should also be provided 180 days instead of 30 days after well completion.

EPA RESPONSE:

We a re soliciting comment on whether 30 days is an appropriate period for the first survey following startup or modification.

7. Reviewer recommends co

- proposing OGI and Method 21 as BSER or proposing Method 21 as BSER and allowing OGI as an accep table compliance mechanism.

EPA RESPONSE: Our BSER analysis is detailed in Section VIII.G, and OGI with semiannual monitoring remains BSER. However, we are taking comment on allowances for use of Method 21 in

certain circumstances. “ As explained above, Method 21 is not as cost

- effective as OGI. That said, there may be reasons why and owner and operator may prefer to use Method 21 over OGI, either for monitoring surveys or re

- survey to assure proper repair. For example even though we e nvision repairs and resurveys to occur during the monitoring survey, there may be components that cannot be immediately repaired and require additional time for such repairs thus requiring the resurveying at a later time. In such situations, an owner and operator may prefer to use Method 21 for resurvey if it is readily available. While we are confident with the ability of Method 21 to detect fugitive emissions and therefore consider it a viable alternative to OGI, we solicit comment on the appropriate fu gitive emissions repair threshold for Method 21 monitoring surveys and re

surveys.”

8. Reviewer recommends not performing LDAR at well sites unless there are gathering lines or well head pressure greater than 150 psi. Reviewer also recommends EPA take comment on varying survey frequencies based on performance criteria.

EPA RESPONSE: Although we agree that pressure can have an effect on occurrence and magnitude of some leaks causing fugitive emissions, we do not have information that would support a

sp ecific threshold. We also note that many fugitive emissions are related to flash emissions from storage vessels combined with undersized closed vent systems that are required to be designed to convey all emissions from the storage vessel to the control

de vice. These emissions are independent of gathering line pressure.