MEMORANDUM 

TO: Docket # EPA-HQ-OAR-2011-0512 

FROM: Alexis McKittrick and Mark Defigueiredo, EPA/CCD

DATE: February 20, 2014 

SUBJECT: Assessment of Impacts of the 2014 Proposed Revisions to Subpart W 

Introduction

The EPA is proposing technical revisions and other clarifications to subpart W of the 

Greenhouse Gas Reporting Rule (40 CFR part 98, subpart W) (hereafter referred to as “subpart 

W”). In this memorandum, we discuss the potential burden to reporters affected by these 

proposed amendments. 

The EPA estimated the cost of the proposed amendments to subpart W as the incremental 

costs above the previously estimated costs of the requirements under subpart W.1

 The EPA 

calculated this incremental cost based on the number of reporters in each segment that are likely 

to be affected by the proposed amendments. The details for estimating this incremental cost (the 

potential burden to reporters) are included in the sections below. 

Costs to reporters associated with this proposal are expressed as labor costs (i.e., the cost 

of labor by facility staff to meet the rule’s proposed amendments). The EPA determined labor 

costs using an approach consistent with previous impacts analyses associated with the 

Greenhouse Gas Reporting Program (GHGRP). For all industry segments the labor rates are 

$78.29 for engineers and $66.57 for technicians.2, 3

 

Summary of Amendments

In this memorandum, we summarize the potential burden to reporters affected by the 

substantive revisions proposed in the rule. In addition to these substantive revisions, the EPA is 

also proposing minor technical revisions to subpart W to improve readability, to create 

 

1

The previously estimated costs of the requirements under subpart W are included in the Information Collection Request for the 

Greenhouse Gas Reporting Program, OMB Control No. 2060-0629, EPA ICR No. 2300.10, May 2013. 2

None of the proposed amendments require an adjustment to middle and senior management labor hours. 3

The engineering and technician labor rates are from the May 2011 National Industry-Specific Occupational Employment and 

Wage Estimates (http://www.bls.gov/oes/current/oessrci.htm) and Employer Costs for Employee Compensation for June of 2011 

(http://www.bls.gov/news.release/archives/ecec_09082011.pdf).
2 

consistency in terminology, and/or to correct typographical or other errors. These minor 

technical revisions would not impart additional burden on reporters and are not discussed in this 

memorandum.4

Well Completions and Workovers 

The EPA is proposing to revise reporting requirements for completions and workovers to 

differentiate between completions and workovers with different well type combinations in each 

sub-basin category. The EPA is proposing to clarify the number of measurements or calculations 

that must be taken to estimate the average ratio of flowback rate (FRM). Reporters may have to 

conduct more tests/measurements, because a separate FRM value is required for each well type. 

This proposed revision represents a potential increase to burden and cost. Using 2012 subpart W 

data reported to EPA as of September 1, 2013, 5

 the EPA determined that 40% of onshore 

production facilities reported completion and workover emissions and 23% of these facilities 

reported emissions from completions under more than one well type. It was estimated that these 

facilities with completions would have to take two additional measurements to determine 

additional FRM values and that an engineer would take approximately 8 hours to conduct each 

additional measurement. Therefore, engineering labor hours (at a cost of $78.29/hour) were 

adjusted upwards by 1.472 hours per reporter. 

The EPA is proposing to modify Equation W-10A (which is a calculation that determines 

annual volumetric total gas emissions from gas well venting during completions or workovers 

following hydraulic fracturing) in order to enable quantification, as opposed to measurement, of 

natural gas emitted during the initial flowback stage of a well when insufficient gas is present to 

enable separation and metering. In addition, the EPA is proposing to modify Equation W-10A to 

ensure reporters account for sales gas volume only once in this calculation. The proposed method 

is similar in complexity as the previous method and uses measurements that are of similar 

complexity; therefore, these proposed changes to Equation W-10A would not impose any 

additional (or reduced) burden and costs. 

The EPA is proposing to revise Equation W-13 (which is a calculation that determines 

annual volumetric total gas emissions from gas well venting during completions or workovers 

without hydraulic fracturing) to separate the calculation of emissions from workovers and the 

calculation of emissions from completions into two equations. Reporters would have to perform 

two calculations as opposed to one; however, it is the same calculation that reporters are 

currently doing broken into two steps. Therefore, these proposed changes to Equation W-13 

would not impose any additional (or reduced) burden and costs. 

 

4

 For explanation of the minor technical revisions refer to the memorandum, “Proposed Minor Technical Corrections to Subpart 

W, Petroleum and Natural Gas Systems, in the Greenhouse Gas Reporting Program” in Docket ID No. EPA-HQ-OAR-2011-

0512. 5

http://ghgdata.epa.gov/ghgp/main.do 
3 

Flare Stack Emissions 

The EPA is proposing to revise the calculation and reporting requirements for onshore 

natural gas transmission compression, underground natural gas storage, liquefied natural gas 

(LNG) storage, and LNG import and export to include emissions from flare stacks. This 

proposed revision represents a potential increase to burden and cost for reporters in these four 

industry segments. Facilities in these industry segments that have flares do not have to report 

flare stack emissions currently, but would need to collect flare data, calculate, and report these 

emissions under the proposed revisions. However, because underground natural gas storage and 

LNG storage facilities do not report flared emissions for compressors, as is required under the 

current rule if these facilities have flares associated with their compressors, the EPA has assumed 

that 0% of these facilities operate flares. Therefore, this proposed revision would not impose any 

additional (or reduced) burden and costs on these two industry segments. 

In order to calculate the potential increase to reporters in the onshore natural gas 

transmission compression and LNG import and export industry segments, the EPA estimated that 

the percent of facilities that would report flare stack emissions was equal to the percent of 

facilities that reported flared emissions for compressors for each of these two industry segments. 

Using subpart W data reported for 2012, 1% of the onshore natural gas transmission compression 

facilities and 50% of LNG import and export facilities reported flared emissions from 

compressors. The incremental increase in hours per reporter was then determined by multiplying 

the percent of facilities that have other flare stacks in each industry segment (i.e., 1% or 50%, 

respectively) by 20 minutes (i.e., the amount of time the EPA estimated an engineer would need 

to collect data and estimate emissions). The result was an estimated increase in the engineering 

labor hours 0.003 hours per reporter (at a rate of $78.29/hour) in the onshore natural gas 

transmission compression industry segment; and an increase of 0.17 hours per reporter (at a rate 

of $78.29/hour) in the LNG import and export industry segment. 

Centrifugal and Reciprocating Compressor Venting 

The EPA is proposing to revise the monitoring requirements so that, in cases where 

multiple compressor sources are manifolded together downstream, reporters can measure 

downstream of the manifold and would not have to measure the compressor sources individually. 

For manifolded compressors, reporters would also have to report activity data for the manifold 

(i.e., number of compressor sources manifolded together, mode of each compressor). Reporters 

would no longer be required to annually measure compressor sources that are manifolded 

individually. Instead, reporters would measure the manifolded group of compressor sources three 

times per year. Therefore, this proposed change is a burden reduction for reporters that have 

more than three compressor sources manifolded together. This proposed revision is expected to 

affect only compressors at onshore natural gas processing facilities, onshore natural gas 

transmission compression facilities, underground natural gas storage facilities, and LNG import 
4 

and export equipment facilities.6 The EPA assumed that facilities with manifolded compressor 

sources would use the proposed option. Therefore, the EPA calculated the decrease in burden 

associated with this proposed measurement option by adjusting engineering and technician labor 

hours downwards per reporter for each industry segment that could use the proposed option. This 

adjustment downward in labor hours was determined by first estimating the average number of 

compressors that are located at a facility in each affected industry segment 7, and then 

multiplying the average number of compressors located at a facility by 10% (because it was 

assumed that 10% of the facilities would have manifolded compressor sources). The EPA then 

took the number of manifolded compressor sources and multiplied it by 10 minutes—the 

estimated time for a technician to take the measurement, and by 30 minutes—the estimated time 

for an engineer to perform the calculation. 

The calculation resulted in a decrease in 0.25 engineering labor hours (at a rate of 

$78.29/hour) and 0.08 technician labor hours (at a rate of $66.75/hour) per reporter for the 

onshore natural gas processing and underground natural gas storage industry segments, a 

decrease in 0.15 engineering labor hours and 0.05 technician labor hours per reporter for the 

onshore natural gas transmission compression industry segment, and a decrease in 0.10 

engineering labor hours and 0.03 technician labor hours per reporter for the LNG import and 

export equipment industry segment. 

In addition, the EPA is proposing to remove vented compressor emissions routed to a 

flare from the compressor emissions total (clarifying that these emissions should be reported in 

the flared emissions total) and retain the requirement to report uncontrolled vented emissions 

from compressors. Reporters would no longer be required to perform individual compressor leak 

measurements or continuous measurements, but rather perform a single calculation under the 

flare stack emissions methodology. The latter would be less burdensome, because it only 

requires reporters to either continuously monitor total flow and composition to the flare or use 

engineering estimates. This proposed amendment is expected to affect only compressors routed 

to a flare at onshore natural gas processing facilities, onshore natural gas transmission 

 

6

 The proposed manifold measurement option would not impact onshore petroleum and natural gas production 

facilities because compressor emission calculation methods are different for this industry segment. It would not 

impact natural gas distribution facilities or offshore petroleum and natural gas production facilities because 

compressor emission calculation methods are not required for these industry segments. It would not impact LNG 

storage facilities because there were only a combined total of three compressors located at two facilities that 

reported compressor emissions for this industry segment according to 2012 subpart W data reported to EPA as of 

September 1, 2013. 

7

 The EPA determined the average number of compressors per facility using 2012 subpart W data reported to EPA 

as of September 1, 2013: 8 compressors at onshore natural gas processing facilities; 6 compressors at onshore 

natural gas transmission compression facilities; 6 compressors at underground natural gas storage facilities; and 

5 compressors at LNG import and export equipment facilities. 
5 

compression facilities, and LNG import and export equipment facilities.8 The EPA calculated the 

decrease in burden associated with this proposed amendment by adjusting engineering and 

technician labor hours downwards per reporter for each affected industry segment. This 

adjustment downward in labor hours was determined by estimating the average number of 

compressors that are located at a facility in each affected industry segment, 9

 and then 

multiplying the average number of compressors located at a facility by the percent of facilities 

with flares in each affected industry segment10 and by the percent of the compressors at these 

facilities that are venting to flares.11 The EPA then multiplied the number of flares (from the 

previous step) by 10 minutes—the estimated time for a technician to take the measurement, and 

by 30 minutes—the estimated time for an engineer to perform the calculation. 

This calculation resulted in a decrease in 0.39 engineering labor hours (at a rate of 

$78.29/hour) and 0.19 technician labor hours (at a rate of $66.57/hour) per reporter for the 

onshore natural gas processing industry segment, a decrease in 0.02 engineering labor hours and 

0.01 technician labor hours per reporter for the onshore natural gas transmission compression 

industry segment, and a decrease in 0.83 engineering labor hours and 0.42 technician labor hours 

per reporter for the LNG import and export equipment industry segment. 

The EPA is also proposing that compressors not measured in the “not-operatingdepressurized-mode” for over three years, must be measured in the “not-operatingdepressurized-mode” at the next scheduled depressurized shutdown (for centrifugal compressors) 

or at the next scheduled shutdown when the compressor rod packing is replaced (for 

reciprocating compressors). Regardless of when the “not-operating-depressurized-mode” would 

be measured, the reporter would still be required to conduct an annual measurement in whatever 

mode the compressor is found. Therefore, the frequency of measurements would be unchanged, 

and this proposed change would not impose any additional (or reduced) burden and costs. 

 

8

 This proposed amendment would not impact onshore petroleum and natural gas production facilities because 

compressor flare emission calculation methods are different for this industry segment. It would not impact natural 

gas distribution facilities or offshore petroleum and natural gas production facilities because compressor flare 

emission calculation methods are not required for these industry segments. It would not impact underground natural 

gas storage and LNG storage facilities because underground natural gas storage and LNG storage facilities do not 

have compressors controlled by flares according to 2012 subpart W data reported to EPA as of September 1, 2013. 

9

The EPA determined the average number of compressors per facility using 2012 subpart W data reported to EPA 

as of September 1, 2013: 8 compressors at onshore natural gas processing facilities; 6 compressors at onshore 

natural gas transmission compression facilities; and 5 compressors at LNG import and export equipment facilities. 10 The EPA determined the percent of facilities with flares using 2012 subpart W data reported to EPA as of 

September 1, 2013: 21% of facilities in onshore natural gas processing; 1% of facilities in onshore natural gas 

transmission compression; and 50% of facilities in LNG import and export equipment). 

11 The EPA determined the percent of the compressors at facilities with flares that are actually venting to flares using 

2012 subpart W data reported to EPA as of September 1, 2013: 68% of the compressors at these facilities are 

venting to flares in onshore natural gas processing; 92% of the compressors at these facilities are venting to flares in 

onshore natural gas transmission compression; and 100% of the compressors at these facilities are venting to flares 

in LNG import and export equipment. 
6 

Pneumatic Devices 

The EPA is proposing to allow either the use of site-specific composition data for natural 

gas transmission compression and underground natural gas storage facilities or the use of a 

default gas composition. The calculation still would be conducted in much the same way that is 

currently required; however, reporters would now be allowed to use site-specific data if data are 

available. Therefore, this proposed change would not impose any additional (or reduced) burden 

and costs. 

Liquids Unloading 

The EPA is proposing to modify the liquids unloading calculation to allow flexibility for 

metered data that do not exactly correspond to a given reporting year. While this modification 

would increase facility flexibility, the calculation still would be conducted in much the same way 

that is currently required. Therefore, this proposed change would not impose any additional (or 

reduced) burden and costs. 

Blowdown Vent Stacks 

The EPA is proposing to revise the calculation for “unique physical volume” so reporters 

can report emissions from blowdown vent stacks by equipment type instead of by “unique 

physical volume.” Although reporters would no longer be required to report blowdown vent 

stack emissions by each “unique physical volume,” reporters still have to calculate blowdown 

vent stack emissions from each “unique physical volume.” Therefore, this proposed change 

would not impose any additional (or reduced) burden and costs. 

The EPA is proposing to add a compressibility term to the blowdown vent stack 

calculations. It is anticipated that reporters handle gas within the proposed compressibility factor 

default ranges; therefore, it is unlikely that adding this compressibility factor term into the 

blowdown vent stack calculations would increase burden to reporters. Therefore, the EPA did 

not estimate the potential burden impact to reporters for this change. 

The EPA is proposing to allow an option to directly measure blowdown emissions in lieu 

of performing “unique physical volume” calculations. Although this option may decrease burden 

for those reporters that currently measure blowdown emissions, because they could simply report 

these measured emissions (without the burden of performing calculations), it is unlikely that 

facilities directly measure all of their “unique physical volumes.” Therefore, the EPA did not 

estimate the potential burden impact to reporters for this change. 

Associated Gas Venting and Flaring 

The EPA is proposing to modify the calculation method for associated gas venting and 

flaring to account for situations where part of the gas is going to the sales line and part of the gas 

emissions are reported under other emission sources included in this subpart (i.e., tank venting). 
7 

The reporter would still have to perform a similar calculation to what is currently being required. 

Although the proposed calculation method modifies the current equation to include two new 

terms, these new terms are already being calculated elsewhere and/or can be estimated. 

Therefore, this proposed change would not impose any additional (or reduced) burden and costs. 

Above Grade Metering-Regulating Stations 

The EPA is proposing technical revisions to the natural gas distribution segment to 

clarify the calculation methodologies and reporting requirements for above grade meteringregulating stations. The EPA would clarify that reporters calculate only two emission factors 

(one for CO2 and one for CH4) for meter/regulator runs instead of separate emission factors for 

all component types. These proposed changes would not impose any additional (or reduced) 

burden and costs. 

Best Available Monitoring Methods (BAMM) 

The EPA is proposing to remove all provisions in 40 CFR 98.234(f) for BAMM. BAMM 

was designed to be a temporary flexibility mechanism and not a permanent option in the rule. 

Therefore, removing BAMM would not change the burden associated with the methods of 

subpart W. 

Missing Data 

Except for missing data that are continuously monitored or measured (for example, flow 

meters), or for missing temperature or pressure data, a complete record of all estimated and/or 

measured parameters used in the GHG emissions calculations is required by the current rule. The 

EPA is proposing certain ways that reporters can substitute a value for certain specific missing 

estimated and/or measured parameters. In addition, for reporters who would be newly subject to 

subpart W in a given reporting year, and for reporters who acquire wells during a reporting year 

that were not subject to subpart W prior to the acquisition, the EPA is proposing to allow the use 

of best engineering estimates for any parameter that cannot be reasonably measured or obtained 

according to the requirements in subpart W for up to six months from the first date of subpart W 

applicability. 

Missing data procedures are currently not included in the greenhouse gas reporting rule 

(Part 98) for many areas of subpart W; however, the proposed missing data procedures would 

provide clarity for reporters who may have unintentionally not monitored required data. The 

proposed language would improve clarity for reporters and would make it easier for reporters to 

determine how to address missing data situations. These proposed changes would not impose any 

additional (or reduced) burden and costs. 
8 

Reporting Provisions 

The EPA is proposing that 245 new data elements be reported. The EPA is also proposing 

to delete 63 data elements, and substantially revise 15 data elements that are currently required to 

be reported under the rule. The proposed new and revise data elements would impose additional 

burden and costs because, for each of the new and revised data elements that would be required 

to be reported, reporters would be required to calculate the data element using readily available 

data, and report the value to the EPA via the EPA’s Electronic Greenhouse Gas Reporting Tool 

(e-GGRT) as part of the annual report currently required under Part 98. The proposed deletion of 

data elements would reduce burden for reporters. 

The EPA calculated the increase in burden associated with new and revised data elements 

by adjusting engineering labor hours upwards per reporter for all industry segments. This 

potential increase in labor hours was determined by first adjusting the number of new and 

revised data elements for each industry segment using the percentage of facilities that reported 

emissions for each emission source, according to 2012 subpart W data reported to the EPA as of 

September 1, 2013.12 The EPA then multiplied the adjusted number of new and revised data 

elements by 3 minutes per data element—the amount time that the EPA estimated an engineer 

would need to access the data element from readily available data and submit the value via eGGRT as part of the annual report currently required under Part 98. Table 1 shows the potential 

labor increase by industry segment that would be associated with the proposed new and revised 

data elements. 

Table 1. Labor Increase Associated with Proposed New and Revised Data Elements 

(by Industry Segment; all are engineering labor hours at $78.29/hour) 

Industry Segment 

Proposed 

New 

Proposed 

Revised 

Adjusted 

New 

Adjusted 

Revised 

Adjusted 

Total 

Total Increase 

in Labor 

Hours per 

Reporter 

Onshore Natural Gas 

Processing 121 6 56 3 59 2.95 

Onshore Natural Gas 

Transmission 

Compression 

99 4 55 2 57 2.85 

Underground Natural 

Gas Storage 82 4 38 2 40 2.00 

LNG Import and Export 

Equipment 86 4 39 2 41 2.05 

Onshore Petroleum and 

Natural Gas Production 124 10 60 5 65 3.25 

Natural Gas Distribution 31 3 18 1 19 0.95 

LNG Storage 79 4 12 0 12 0.60 

Offshore Petroleum and 

Natural Gas Production 3 0 3 0 3 0.15 

 

12

 This adjustment is necessary because not all facilities report data for each emission source. 
9 

The EPA calculated the decrease in burden associated with deletion of data elements by 

adjusting engineering labor hours downwards per reporter for all affected industry segments. 

This decrease in labor hours was determined by first adjusting the number of data elements 

proposed to be deleted for each industry segment using the percentage of facilities that reported 

emissions for each emission source, according to 2012 subpart W data reported to the EPA as of 

September 1, 2013.13 The EPA then multiplied the adjusted number of data elements proposed to 

be deleted by 3 minutes—the amount of time that the EPA estimated an engineer would save 

because they would no longer need to access the data element and submit the value via e-GGRT 

as part of the annual report currently required under Part 98. Table 2 shows the labor adjustment 

by industry segment that would be associated with the data elements proposed to be deleted. 

Table 2. Labor Decrease Associated with Data Elements Proposed to be Deleted 

(by Industry Segment; all are engineering labor hours at $78.29/hour) 

Industry Segment Proposed 

Deleted 

Adjusted 

Deleted 

Total Decrease in Labor 

Hours per Reporter 

Onshore Natural Gas Processing 23 12 -0.60 

Onshore Natural Gas Transmission Compression 21 14 -0.70 

Underground Natural Gas Storage 14 5 -0.25 

LNG Import and Export Equipment 21 10 -0.50 

Onshore Petroleum and Natural Gas Production 20 16 -0.80 

Natural Gas Distribution 21 21 -1.05 

LNG Storage 14 1 -0.05 

Offshore Petroleum and Natural Gas Production 0 0 0 

For additional information on the proposed changes to the reporting provisions, see the 

memo, “Revisions to the Subpart W Reporting Requirements as proposed in the ‘Greenhouse 

Gas Reporting Rule: Revisions and Confidentiality Determinations for Petroleum and Natural 

Gas Systems; Proposed Rule’” in Docket Id. No. EPA-HQ-OAR-2011-0512. 

Results of Analysis

The estimated change in burden (labor hours) and cost for the proposed amendments to 

subpart W are summarized by industry segment in Table 3. 

 

13

 Ibid. 
10 

Table 3. Annual Average Change in Reporter Burden and 

Cost for Proposed Subpart W of the GHGRP 

Subpart W Industry Segment 

Change In 

Total Burden 

(Technical 

Labor Hours) 

Change In 

Burden 

(Technical 

Labor Hours / 

Reporter) 

Change In 

Total Cost 

($) 

Change In 

Cost 

($ / Reporter) 

Onshore Natural Gas Processing a 417 1.43 $33,612 $116 

Onshore Natural Gas Transmission 

Compression b

 2,221 1.93 $174,662 $152 

Underground Natural Gas Storage c 197 1.42 $15,552 $112 

LNG Import and Export Equipment d 1 0.33 $125 $31 

Onshore Petroleum and Natural Gas 

Production e

 4,062 3.93 $317,186 $307 

Natural Gas Distribution f -8 -0.05 -$622 -$4 

LNG Storage g 18 0.52 $1,507 $43 

Offshore Petroleum and Natural Gas 

Production h

 11 0.15 $846 $12 

TOTAL 6,920 --- $542,868 --- 

a

 For onshore natural gas processing, the technical labor hour burden increased from 25,495 hours to 25,912 hours, which increased the total 

cost from $2,346,000 to $2,380,000. b

 For onshore natural gas transmission compression, the technical labor hour burden increased from 75,506 hours to 77,727 hours, which 

increased the total cost from $7,554,000 to $7,482,000. c

 For underground natural gas storage, the technical labor hour burden increased from 12,450 hours to 12,646 hours, which increased the total 

cost from $1,164,000 to $1,180,000. d

 For LNG import and export equipment, the technical labor hour burden increased from 367 hours to 368 hours, which increased the total cost 

from $39,200 to $39,300. e

 For onshore petroleum and natural gas production, the technical labor hour burden increased from 97,754 hours to 101,816 hours, which 

increased the total cost from $8,334,000 to $8,651,000. f For natural gas distribution, the technical labor hour burden increased from 18,986 hours to 18,979 hours, which increased the total cost from 

$1,659,000 to $1,658,000. g

 For LNG storage, the technical labor hour burden increased from 2,954 hours to 2,973 hours, which increased the total cost from $286,000 to 

$287,000. h

 For offshore petroleum and natural gas production, the technical labor hour burden increased from 3,220 hours to 3,231 hours, which increased 

the total cost from $285,000 to $286,000.