[Federal Register Volume 79, Number 46 (Monday, March 10, 2014)]
[Proposed Rules]
[Pages 13393-13460]
[FR Doc No: 2014-04408]

Vol. 79

Monday,

No. 46

March 10, 2014

Part II

Environmental Protection Agency

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40 CFR Part 98

Greenhouse Gas Reporting Rule: Revisions and Confidentiality
Determinations for Petroleum and Natural Gas Systems; Proposed Rule

Federal Register / Vol. 79 , No. 46 / Monday, March 10, 2014 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 98

[EPA-HQ-OAR-2011-0512; FRL-9906-85-OAR]
RIN 2060-AR96

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing revisions and confidentiality
determinations for the petroleum and natural gas systems source
category and the general provisions of the Greenhouse Gas Reporting
Rule. In particular, the EPA is proposing to revise certain calculation
methods, amend certain monitoring and data reporting requirements,
clarify certain terms and definitions, and correct certain technical
and editorial errors that have been identified during the course of
implementation. This action also proposes confidentiality
determinations for new or substantially revised data elements contained
in these proposed amendments, as well as proposes a revised
confidentiality determination for one existing data element.

DATES: Comments. Comments must be received on or before April 24, 2014.
    Public Hearing. The EPA does not plan to conduct a public hearing
unless requested. To request a hearing, please contact the person
listed in the following FOR FURTHER INFORMATION CONTACT section by
March 17, 2014. If requested, the hearing will be conducted on March
25, 2014, in the Washington, DC area. The EPA will provide further
information about the hearing on the Greenhouse Gas Reporting Rule Web
site, http://www.epa.gov/ghgreporting/index.html if a hearing is
requested.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2011-0512 by any of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov.
Follow the online instructions for submitting comments.
     Email<EMAIL_ADDRESS>Include Docket ID No. EPA-HQ-OAR-2011-0512 or RIN No.
2060-AR96 in the subject line of the message.
     Fax:<PHONE_NUMBER>.
     Mail: Environmental Protection Agency, EPA Docket Center
(EPA/DC), Mailcode 28221T, Attention Docket ID No. OAR-2011-0512, 1200
Pennsylvania Avenue NW., Washington, DC 20460.
     Hand/Courier Delivery: EPA Docket Center, Public Reading
Room, William Jefferson Clinton (WJC) West Building, Room 3334, 1301
Constitution Avenue NW., Washington, DC 20004. Such deliveries are
accepted only during the normal hours of operation of the Docket
Center, and special arrangements should be made for deliveries of boxed
information.
    Additional Information on Submitting Comments: To expedite review
of your comments by agency staff, you are encouraged to send a separate
copy of your comments, in addition to the copy you submit to the
official docket, to Carole Cook, U.S. EPA, Office of Atmospheric
Programs, Climate Change Division, Mail Code 6207-J, 1200 Pennsylvania
Avenue NW., Washington, DC 20460, telephone<PHONE_NUMBER>, email
address<EMAIL_ADDRESS>    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2011-0512, Greenhouse Gas Reporting Rule: Revisions and Confidentiality
Determinations for Petroleum and Natural Gas Systems; Proposed Rule.
The EPA's policy is that all comments received will be included in the
public docket without change and may be made available online at http://www.regulations.gov, including any personal information provided,
unless the comment includes information claimed to be confidential
business information (CBI) or other information whose disclosure is
restricted by statute.
    Should you choose to submit information that you claim to be CBI,
clearly mark the part or all of the information that you claim to be
CBI. For information that you claim to be CBI in a disk or CD-ROM that
you mail to the EPA, mark the outside of the disk or CD-ROM as CBI and
then identify electronically within the disk or CD-ROM the specific
information that is claimed as CBI. In addition to one complete version
of the comment that includes information claimed as CBI, a copy of the
comment that does not contain the information claimed as CBI must be
submitted for inclusion in the public docket. Information marked as CBI
will not be disclosed except in accordance with procedures set forth in
40 CFR part 2. Send or deliver information identified as CBI to only
the mail or hand/courier delivery address listed above, attention:
Docket ID No. EPA-HQ-OAR-2011-0512. If you have any questions about CBI
or the procedures for claiming CBI, please consult the person
identified in the FOR FURTHER INFORMATION CONTACT section.
    Do not submit information that you consider to be CBI or otherwise
protected through http://www.regulations.gov or email. The http://www.regulations.gov Web site is an ``anonymous access'' system, which
means the EPA will not know your identity or contact information unless
you provide it in the body of your comment. If you send an email
comment directly to the EPA without going through http://www.regulations.gov your email address will be automatically captured
and included as part of the comment that is placed in the public docket
and made available on the Internet. If you submit an electronic
comment, the EPA recommends that you include your name and other
contact information in the body of your comment and with any disk or
CD-ROM you submit. If the EPA cannot read your comment due to technical
difficulties and cannot contact you for clarification, the EPA may not
be able to consider your comment. Electronic files should avoid the use
of special characters, any form of encryption, and be free of any
defects or viruses.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Air Docket, EPA/
DC, WJC West Building, Room 3334, 1301 Constitution Ave. NW.,
Washington, DC. This Docket Facility is open from 8:30 a.m. to 4:30
p.m., Monday through Friday, excluding legal holidays. The telephone
number for the Public Reading Room is<PHONE_NUMBER>, and the telephone
number for the Air Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: Carole Cook, Climate Change Division,
Office of Atmospheric Programs (MC-6207J), Environmental Protection
Agency, 1200 Pennsylvania Ave. NW., Washington, DC 20460; telephone
number:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>; email address:
<EMAIL_ADDRESS>For technical information, please go to the
Greenhouse Gas Reporting Rule Web site, http://www.epa.gov/
ghgreporting/

index.html. To submit a question, select Help Center, followed by
``Contact Us.''
    Worldwide Web (WWW). In addition to being available in the docket,
an electronic copy of today's proposal will also be available through
the WWW. Following the Administrator's signature, a copy of this action
will be posted on EPA's Greenhouse Gas Reporting Rule Web site at
http://www.epa.gov/ghgreporting/index.html.

SUPPLEMENTARY INFORMATION:
    Regulated Entities. The Administrator determined that this action
is subject to the provisions of Clean Air Act (CAA) section 307(d). See
CAA section 307(d)(1)(V) (the provisions of section 307(d) apply to
``such other actions as the Administrator may determine''). These are
proposed amendments to existing regulations. If finalized, these
amended regulations would affect owners or operators of petroleum and
natural gas systems that directly emit greenhouse gases (GHGs).
Regulated categories and entities include those listed in Table 1 of
this preamble:

           Table 1--Examples of Affected Entities by Category
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                                                   Examples of affected
            Category                  NAICS             facilities
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Petroleum and Natural Gas                486210  Pipeline transportation
 Systems.                                         of natural gas.
                                         221210  Natural gas
                                                  distribution.
                                         211111  Crude petroleum and
                                                  natural gas
                                                  extraction.
                                         211112  Natural gas liquid
                                                  extraction.
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    Table 1 of this preamble is not intended to be exhaustive, but
rather provides a guide for readers regarding facilities likely to be
affected by this action. Other types of facilities than those listed in
the table could also be subject to reporting requirements. To determine
whether you are affected by this action, you should carefully examine
the applicability criteria found in 40 CFR part 98, subpart A and 40
CFR part 98, subpart W. If you have questions regarding the
applicability of this action to a particular facility, consult the
person listed in the preceding FOR FURTHER INFORMATION CONTACT section.
    Acronyms and Abbreviations. The following acronyms and
abbreviations are used in this document.

BAMM best available monitoring methods
CAA Clean Air Act
CBI confidential business information
CFR Code of Federal Regulations
CH4 methane
CO2 carbon dioxide
CO2e carbon dioxide equivalent
EIA Energy Information Administration
EOR enhanced oil recovery
EPA U.S. Environmental Protection Agency
FERC Federal Energy Regulatory Commission
FR Federal Register
GHG greenhouse gas
GOR gas to oil ratio
GWP global warming potential
LNG liquefied natural gas
MMscf million standard cubic feet per day
N2O nitrous oxide
NAICS North American Industry Classification System
NGL natural gas liquids
NTTAA National Technology Transfer and Advancement Act
OMB Office of Management and Budget
QA/QC quality assurance/quality control
RFA Regulatory Flexibility Act
scf standard cubic feet
TSD Technical Support Document
UIC underground injection control
U.S. United States
UMRA Unfunded Mandates Reform Act of 1995

Organization of This Document. The following outline is provided to aid
in locating information in this preamble.

I. Background
    A. Organization of This Preamble
    B. Background on the Proposed Action
    C. Legal Authority
    D. How would these amendments apply to 2014 and 2015 reports?
II. Revisions and Other Amendments
    A. Proposed Revisions To Provide Consistency Throughout Subpart
W
    B. Proposed Changes to Calculation Methods and Reporting
Requirements
    C. Proposed Revisions to Missing Data Provisions
    D. Proposed Amendments to Best Available Monitoring Methods
III. Proposed Confidentiality Determinations
    A. Overview and Background
    B. Approach to Proposed CBI Determinations for New or Revised
Subpart W Data Elements
    C. Proposed Confidentiality Determinations for Data Elements
Assigned to the ``Unit/Process `Static' Characteristics That Are Not
Inputs to Emission Equations'' and ``Unit/Process Operating
Characteristics That Are Not Inputs to Emission Equations'' Data
Categories
    D. Other Proposed or Re-Proposed Case-by-Case Confidentiality
Determinations for Subpart W
    E. Request for Comments on Proposed Confidentiality
Determinations
IV. Impacts of the Proposed Amendments to Subpart W
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations

I. Background

A. Organization of This Preamble

    The first section of this preamble provides background information
regarding the origin of the proposed amendments. This section also
discusses the EPA's legal authority under the CAA to promulgate and
amend 40 CFR part 98 of the Greenhouse Gas Reporting Rule (hereinafter
referred to as ``Part 98'') as well as the legal authority for making
confidentiality determinations for the data to be reported. Section II
of this preamble contains information on the proposed revisions to 40
CFR part 98, subpart W (hereafter referred to as ``subpart W'').
Section III of this preamble discusses proposed confidentiality
determinations for new or substantially revised (i.e., requiring
additional or different data to be reported) data reporting elements,
as well as a proposed revised confidentiality determination for one
existing data element. Section IV of this preamble discusses the
impacts of the proposed amendments to subpart W. Finally, Section V of
this preamble describes the statutory and executive order requirements
applicable to this action.

B. Background on the Proposed Action

    On October 30, 2009, the EPA published Part 98 for collecting
information regarding greenhouse gases (GHGs) from a broad range of
industry sectors (74 FR 56260). The 2009 rule,

which finalized reporting requirements for 29 source categories, did
not include the petroleum and natural gas systems source category. A
subsequent rule was published on November 20, 2010 finalizing the
requirements for the petroleum and natural gas systems source category
at 40 CFR part 98, subpart W (75 FR 74458) (hereafter referred to as
``the final subpart W rule''). Following promulgation, the EPA
finalized actions revising subpart W (76 FR 22825, April 25, 2011; 76
FR 59533, September 27, 2011; 76 FR 80554, December 23, 2011; 77 FR
51477, August 24, 2012; 78 FR 25392, May 1, 2013; 78 FR 71904, Nov. 29,
2013).
    In this action, the EPA is proposing to make certain revisions to
the petroleum and natural gas systems source category GHG reporting
requirements (Part 98, subpart W) and one clarifying edit to a
definition in the general provisions source category (Part 98, subpart
A). The proposed changes revise certain calculation methods, amend
certain monitoring and data reporting requirements, clarify certain
terms and definitions, and correct certain technical and editorial
errors identified during the course of implementation. The proposed
revisions were identified from the verification of annual reports,
review of Best Available Monitoring Method (BAMM) request submittals,
and questions raised by reporting entities. In conjunction with this
action, we are proposing confidentiality determinations for the new and
substantially revised (i.e., requiring additional or different data to
be reported) data elements contained in these proposed amendments, as
well as proposing a revised confidentiality determination for one
existing data element.

C. Legal Authority

    The EPA is proposing these rule amendments under its existing CAA
authority provided in CAA section 114. As stated in the preamble to the
2009 final GHG reporting rule (74 FR 56260, October 30, 2009), CAA
section 114(a)(1) provides the EPA broad authority to require the
information proposed to be gathered by this rule because such data
would inform and are relevant to the EPA's carrying out a wide variety
of CAA provisions. See the preambles to the proposed (74 FR 16448,
April 10, 2009) and final GHG reporting rule (74 FR 56260, October 30,
2009) for further information.
    In addition, the EPA is proposing confidentiality determinations
for proposed new or substantially revised data elements in subpart W,
as well as proposing a revised confidentiality determination for one
existing data element, under its authorities provided in sections 114,
301, and 307 of the CAA. Section 114(c) requires that the EPA make
information obtained under section 114 available to the public, except
where information qualifies for confidential treatment. The
Administrator has determined that this action is subject to the
provisions of section 307(d) of the CAA.

D. How would these amendments apply to 2014 and 2015 reports?

    The EPA is planning to address the comments we receive on these
proposed changes and publish the final amendments before the end of
2014. If finalized, these amendments would become effective on January
1, 2015. Facilities would therefore be required to follow the revised
methods in subpart W, as amended, to calculate emissions beginning
January 1, 2015 (i.e., beginning with the 2015 reporting year). The
first annual reports of emissions calculated using the amended
requirements would be those submitted by March 31, 2016, which would
cover the 2015 reporting year. For the 2014 reporting year, reporters
would continue to calculate emissions and other relevant data for the
reports that are submitted according to the requirements of 40 CFR part
98 that are applicable to the 2014 reporting year (i.e. those currently
in effect).

II. Revisions and Other Amendments

    The amendments to subpart W that the EPA is proposing include the
following types of changes:
     Changes to clarify or simplify calculation methods for
certain sources at a facility, and reduce some of the burden associated
with data collection and reporting.
     Revisions to units of measure, terms, and definitions in
certain equations to provide consistency throughout the rule, provide
clarity, or better reflect facility operations.
     Revisions to reporting requirements to clarify and align
more closely with the calculation methods and to clearly identify the
data that must be reported for each source type.
     Other amendments and revisions identified as a result of
working with the affected sources during rule implementation and
outreach.
    In addition to the specific revisions or amendments discussed in
this section of the preamble, the EPA is proposing several minor
technical revisions to subpart W to improve readability, to create
consistency in terminology, and/or to correct typographical or other
errors. These proposed revisions contained in the proposed regulatory
text are further explained in 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. The EPA invites public comment on the revisions identified
in this memorandum, as well as those outlined in this preamble.

A. Proposed Revisions To Provide Consistency Throughout Subpart W

1. Consistency in Units of Measure for Emissions Reporting
    Currently, subpart W requires that reported GHG emissions be
expressed in metric tons of CO2 equivalent
(CO2e). The EPA is proposing to amend 40 CFR 98.236 to
revise the reporting of GHG emissions from units of metric tons of
CO2e of each reported GHG to metric tons of each reported
GHG. These proposed changes would increase consistency between the
reporting requirements for subpart W and the rest of Part 98, because
other subparts of Part 98 generally require the reporting of metric
tons of individual GHGs instead of metric tons of CO2e.
Reporters would use the global warming potentials (GWPs) in Table A-1
of 40 CFR Part 98, subpart A, as required in 40 CFR 98.2(b)(4), to
calculate annual emissions aggregated for all GHGs from all applicable
source categories in metric tons of CO2e for their annual
reports.
    Specifically, we are proposing to revise the units of emissions
reported in 40 CFR 98.236 to require reporting in metric tons of
methane (CH4), carbon dioxide (CO2), and nitrous
oxide (N2O), as applicable, instead of reporting each gas in metric
tons of CO2e. We are also proposing to revise certain
calculation methods that require the calculation of emissions in
CO2e. For example, subpart W total GHG emissions are
calculated using equations that reference GWPs (Equations W-36 and W-
40). We are proposing to amend each equation referencing GWPs
separately to remove the conversion factors and GWPs that are built
into the equations, and allow for calculation of individual GHG
emissions in metric tons.
    The proposed revisions reduce the likelihood of errors and
inconsistencies, because it reduces the number of calculations that
need to be completed by reporters and removes some variability in how
different reporters may complete these calculations (e.g., a reporter
could inadvertently use the wrong GWP). The proposed changes would also
simplify analysis of emissions on a GHG-specific basis,

which would facilitate the verification of reported data. In addition,
this proposed change would align subpart W with the manner of reporting
for most other subparts of Part 98.
2. Onshore Production Source Category Definition
    We are proposing to revise the source category definition of
onshore petroleum and natural gas production at 40 CFR 98.230(a)(2) to
clarify the emission sources covered for purposes of GHG reporting. The
proposed amendments clarify the types of emission sources in the
onshore petroleum and natural gas production source category to which
the reporting requirements of subpart W apply. Specifically, we are
proposing to add references to engines, boilers, heaters, flares,
separation and processing equipment, and maintenance and repair
equipment and to remove references to gravity separation equipment and
auxiliary non-transportation-related equipment. Thus, the first
sentence of 40 CFR 98.230(a)(2) is proposed to read as follows:
``Onshore petroleum and natural gas production means all equipment on a
single well-pad or associated with a single well-pad (including but not
limited to compressors, generators, dehydrators, storage vessels,
engines, boilers, heaters, flares, separation and processing equipment,
and portable non-self-propelled equipment which includes well drilling
and completion equipment, workover equipment, maintenance and repair
equipment, and leased, rented or contracted equipment) used in the
production, extraction, recovery, lifting, stabilization, separation or
treating of petroleum and/or natural gas (including condensate).'' The
references to gravity separation equipment and auxiliary non-
transportation-related equipment in the current rule are redundant with
other sources specified in the definition. The proposed amendments do
not subject new emission sources to the reporting requirements and do
not remove sources currently covered from the reporting requirements,
but rather provide a more accurate description of the industry segment
for purposes of GHG reporting.
3. Definition of Sub-Basin Category
    The EPA is proposing to revise the definition of sub-basin category
at 40 CFR 98.238 to clarify coverage for purposes of GHG reporting due
to issues identified during implementation. Specifically, we are
proposing to define sub-basin category as ``a subdivision of a basin
into the unique combination of wells with the surface coordinates
within the boundaries of an individual county and subsurface completion
in one or more of each of the following five formation types: Oil, high
permeability gas, shale gas, coal seam, or other tight gas reservoir
rock. The distinction between high permeability gas and tight gas
reservoirs shall be designated as follows: High permeability gas
reservoirs with >0.1 millidarcy permeability, and tight gas reservoirs
with <=0.1 millidarcy permeability. Permeability for a reservoir type
shall be determined by engineering estimate. Wells that produce only
from high permeability gas, shale gas, coal seam, or other tight gas
reservoir rock are considered gas wells; gas wells producing from more
than one of these formation types shall be classified into only one
type based on the formation with the most contribution to production as
determined by engineering knowledge. All wells that produce hydrocarbon
liquids (with or without gas) and do not meet the definition of a gas
well in this sub-basin category definition are considered to be in the
oil formation. All emission sources that handle condensate from gas
wells in high permeability gas, shale gas, or tight gas reservoir rock
formations are considered to be in the formation that the gas well
belongs to and not in the oil formation.'' The EPA is proposing these
edits to clarify that ``tight gas reservoir rock'' generally refers to
tight reservoir rock formations that produce gas, and not tight
reservoir rock formations that produce only oil, and that wells that
produce liquids in a sub-basin from formations other than high
permeability gas, shale gas, coal seam, or other tight gas reservoir
rock are considered oil wells.

B. Proposed Changes to Calculation Methods and Reporting Requirements

    This section describes proposed changes or corrections to
calculation methods and reporting requirements. In general, the
proposed revisions to calculation methods would provide greater
flexibility and potentially reduce burden to facilities (e.g., by
increasing options for calculating emissions from compressors), and
increase clarity and congruency of calculation and reporting
requirements (e.g., by clarifying which reporting requirements apply to
which calculation methods). The EPA is also proposing minor technical
revisions to the calculation methods of subpart W, such as making
equation variables and definitions consistent across multiple equations
that identify the same parameters, or clarifying requirements that have
caused confusion. Please see the memo, ``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, for more information on the minor technical revisions included in
this proposal.
    We are also proposing revisions to the reporting requirements in 40
CFR 98.236. The proposed revisions would restructure the reporting
requirements, make reporting requirements consistent with the
calculation methods, clarify the data elements to be reported, and
improve data utility. In the current subpart W rule, slight
inconsistencies between the calculation and the reporting sections have
caused confusion among some reporters. In order to improve the quality
of the data reported, we are proposing to revise reporting requirements
that more clearly align with the calculation methods for each source
type.
    We are proposing to reorganize the reporting section by source type
(e.g., natural gas pneumatic device venting, acid gas removal vents,
etc.) and, for each industry segment, list which source types must be
reported. These proposed changes would clarify the reporting
requirements for each industry segment and streamline verification by
reducing the amount of correspondence with facilities during
verification regarding required data elements that were not reported.
Although the proposed reporting requirements appear lengthier, the
revisions separate the requirements into discrete reporting elements in
order to facilitate reporting and improve data collection. The proposed
revisions to the reporting requirements in 40 CFR 98.236 will clarify
which data elements are required to be reported for which facilities.
For example, in reviewing the current subpart W reporting forms, if a
reporter left certain fields blank in the reporting form (e.g.,
emissions from flaring), the EPA has been unable to discern whether the
field was left blank intentionally. Because the proposed 40 CFR 98.236
would clearly define each data element for each emission source in each
industry segment that must be reported, it would clarify which fields
in the subpart W reporting form should be populated. In some cases, we
are also proposing to add additional data elements to improve the
quality of the data reported. The reporting of these proposed data
elements would improve verification of reported emissions and reduce
the amount of correspondence with reporters that is associated with
follow-up and revision of annual reports. In nearly all cases, the new
data elements are based on data that are

already collected by the reporter or are readily available to the
reporter, and would not require additional monitoring or data
collection. For additional information on the proposed changes to the
reporting section, see the memo, ``Proposed Revisions to the Subpart W
Reporting Requirements'' in Docket Id. No. EPA-HQ-OAR-2011-0512.
1. Natural Gas Pneumatic Device Venting
    The EPA is proposing to revise the calculation method for natural
gas pneumatic device venting to expand the use of site-specific data on
gas compositions, if available, for facilities in the onshore natural
gas transmission compression and underground natural gas storage
industry segments. The final subpart W rule provides default natural
gas compositions of 95 percent CH4 and 1 percent
CO2 for onshore natural gas transmission compression and
underground natural gas storage, when calculating CH4 and
CO2 volumetric emissions from transmission storage tanks
(transmission compression), blowdown vent stacks (transmission
compression), and compressor venting (40 CFR 98.233(u)(2)(iii) and
(iv)). The provisions of 40 CFR 98.233(u)(2) only allow default gas
compositions to be used, unless otherwise specified in 40 CFR
98.233(u)(2) (i.e., for onshore production and natural gas processing).
    We are 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 (95 percent CH4 and 1 percent CO2).
Specifically, we are proposing to revise the parameter ``GHGi'' in
Equation W-1 to remove the default gas composition for CH4
and CO2 and to direct reporters to use the concentrations
determined as specified in 40 CFR 98.233(u)(2)(i), (iii), and (iv).
This amendment addresses reporter concerns and improves data quality
for those using site-specific data. The proposed changes are consistent
with provisions for other applicable emission sources at natural gas
transmission compression and underground storage facilities and would
allow a consistent gas composition to be used for all sources at a
facility. The calculation still must be conducted in much the same way
that is currently required; however, we are proposing that reporters be
allowed to use site-specific data if they are available. Therefore, the
EPA does not anticipate that this proposed change will significantly
affect the reporting burden. The EPA requests comment on whether the
use of site-specific composition data for calculating emissions should
be required or optional. The EPA also requests comment and specific
details on when, if ever, a facility would not have site-specific gas
composition data available.
    We are also proposing to revise the natural gas pneumatic device
venting calculations (40 CFR 98.233(a)(1), (a)(2), and (a)(3)) to
simplify how ``Countt'' of Equation W-1 (total number of
natural gas pneumatic devices) must be calculated each year as new
devices are added. The revisions clarify that for all industry
segments, the reported number of devices must represent the total
number of devices for the reporting year. For the onshore petroleum and
natural gas production industry segment, reporters would continue to
have the option in the first two reporting years to estimate
``Countt'' using engineering estimates.
2. Acid Gas Removal Vents
    For acid gas removal vents, we are proposing minor clarifying edits
to 40 CFR 98.233(d) to clearly label each calculation method and to
clarify provisions by providing references to equations where
appropriate. We are also proposing to revise the parameters
``VolCO2'' in Equation W-3 and parameters
``VolI'' and ``VolO'' in Equation W-4A and W-4B
to clarify that the volumetric fraction used should be the annual
average. We are also proposing to specify in 40 CFR 98.233(d)(8) that
reporters may use sales line quality specifications for CO2
in natural gas only if a continuous gas analyzer is not available.
3. Dehydrators
    We are proposing to revise the dehydrator vents source by
renumbering and revising the dehydrator calculation method for
desiccant dehydrators in order to clarify the adjustment of emissions
to account for venting to a vapor recovery system or to a flare (40 CFR
98.233(e)). The proposed amendments provide for the adjustment of
emissions vented to a vapor recovery system or flare (40 CFR
98.233(e)(5) and (e)(6)) for desiccant dehydrators because in the final
subpart W rule, it was not clear how such an adjustment would be made.
As such, we are clarifying the calculation methods for desiccant
dehydrators that vent to a flare or vapor recovery device.
4. Well Venting for Liquids Unloading
    The EPA is proposing to revise the calculation and reporting
requirements for well venting from liquids unloading to allow for
annualizing venting data for facilities that calculate emissions using
a recording flow meter (Calculation Method 1). This proposed amendment
would address reporter concerns and simplify reporting. Some reporters
have expressed difficulty in collecting well venting data using a
recording flow meter for the exact period of January 1 to December 31,
because they contend that it would require them to be physically
present at each recording flow meter on December 31. The EPA is
proposing to revise Calculation Method 1 (40 CFR 98.233(f)(1)) such
that reporters may use an annualized value to determine the cumulative
amount of time of venting (``Tp'' in Equation W-7A and W-7B)
if data are not available for the specific time period January 1 to
December 31. We are specifying that if an annualized value is used, the
monitoring period must begin before February 1 and must not end before
December 1 of the reporting year, and that a minimum of 300 consecutive
days must be used by reporters to determine the annualized vent time.
The EPA is also proposing that the date of the end of one monitoring
period must be the start of the next monitoring period for the next
reporting year, and that all days must be monitored and all venting
accounted for. We are proposing that if a reporter uses a monitoring
period other than a full calendar year for any well, they must report
the percentage of wells for which a monitoring period other than a full
calendar year is used. Although the proposed change increases
flexibility, the calculation still must be conducted in much the same
way that is currently required. Therefore, the EPA does not anticipate
that this proposed change will significantly affect reporting burden.
    We are proposing to change Calculation Method 1 at 40 CFR
98.233(f)(1) to separate the calculation and reporting of emissions
from wells that have plunger lifts and wells that do not have plunger
lifts. This separation would allow the EPA and the public to more
easily disaggregate emission data and activity data for wells that have
plunger lifts and wells that do not have plunger lifts. We are
proposing a clarification to Calculation Method 2 in 40 CFR
98.233(f)(2) to clarify that this method is used for wells without
plunger lifts.
    In a harmonizing change, the EPA is proposing to revise the
reporting requirement for reporters using Calculation Method 1, under
40 CFR 98.236 such that reporters would be required to report the
cumulative amount of time of venting for each group of wells during the
year. Calculation Method 1 uses the cumulative amount of time of
venting and not the number of venting events,

to calculate emissions; therefore, this revision would align the
reporting requirement with the calculation method. We are proposing
harmonizing changes to 40 CFR 98.236 to separate the reporting of
emissions from wells with and without plunger lifts when Calculation
Method 1 is used.
    We are also proposing to amend the definition of the term ``SPp''
in Equation W-8 (40 CFR 98.233(f)(2)) to clarify that if casing
pressure is not available for each well, reporters may determine the
casing pressure using a ratio of the casing pressure to tubing pressure
from a well in the same sub-basin where the casing pressure is known.
This amendment would improve the consistency of the calculation method
used to determine casing pressure across reporters.
    We are also proposing to revise 40 CFR 98.236 to require that
facilities using Calculation Methods 1, 2, and 3 report a separate
count of wells with plunger lifts and wells without plunger lifts, and
to report annual emissions separately from each of those sources,
respectively. We are also proposing to amend 40 CFR 98.236 to require
the reporting of the cumulative number of unloadings from wells with
plunger lifts and unloadings from wells without plunger lifts, the
average flow rate of the measured well venting for wells with and
without plunger lifts, and the internal casing or tubing diameters and
pressures for wells with and without plunger lifts, as applicable.
These proposed revisions break out the existing count and emissions
reporting requirements to more clearly specify the sources of emissions
at facilities. For further information on well venting for liquids
unloading, see the Technical Support Document (TSD) ``Greenhouse Gas
Reporting Rule: Technical Support for Revisions and Confidentiality
Determinations for Petroleum and Natural Gas Systems; Proposed Rule''
in Docket ID No. EPA-HQ-OAR-2011-0512.
5. Gas Well Completions And Workovers
    The EPA is proposing to amend 40 CFR 98.238 to add definitions for
``reduced emissions completion'' and ``reduced emissions workover''.
Currently, reduced emissions completions and reduced emission workovers
are mentioned in the relevant calculation method as equipment that
separates natural gas from the backflow and sends this natural gas to a
flow-line. However, there are currently no defined terms for reduced
emissions completions and reduced emissions workovers. The EPA notes
that since the time that subpart W was promulgated, the EPA promulgated
new source performance standards for the oil and natural gas sector
under 40 CFR Part 60, subpart OOOO, that requires the use of a reduced
emissions completion in specified circumstances. The EPA proposes to
add a definition for ``reduced emissions completion'' to subpart W that
would be consistent with the description of that term in the new source
performance standard rulemaking (see 76 FR 52757-8). Specifically, the
EPA is proposing to amend 40 CFR 98.238 to define a ``reduced emissions
completion'' as a well completion following fracturing where gas
flowback that is otherwise vented is captured, cleaned, and routed to
the flow line or collection system, re-injected into the well or
another well, used as an on-site fuel source, or used for other useful
purpose that a purchased fuel or raw material would serve, with no
direct release to the atmosphere. We are proposing to amend 40 CFR
98.238 to define a ``reduced emissions workover'' as a well workover
with hydraulic fracturing (i.e., refracturing) where gas flowback that
is otherwise vented is captured, cleaned, and routed to the flow line
or collection system, re-injected into the well or another well, used
as an on-site fuel source, or used for other useful purpose that a
purchased fuel or raw material would serve, with no direct release to
the atmosphere. The EPA does not anticipate these definitional changes
would impact current reporters under Part 98 because these changes are
clarifying in nature and do not change any requirements of subpart W.
    The EPA is also proposing to amend the definition of ``well
completions'' in 40 CFR 98.6 to delete the term ``re-fracture'' as this
term applies to an already producing well and is considered a well
workover, not a well completion, for the purposes of part 98. This
amendment is intended to avoid potential confusion concerning whether a
re-fracture is a completion or workover in the context of subpart W.
This change will also better align the existing definition of ``well
completions'' with the new proposed definition of a ``reduced emissions
completion'' by clarifying that a reduced emission completion only
applies to new fractures and that re-fractures are potentially covered
under the new definition of ``reduced emission workover''. The
definition of ``well workover'' in 40 CFR 98.6 already refers to re-
fractures, so no clarifying change is needed for that definition.
    We are also 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. A well type combination is a unique combination of the
following factors: Vertical or horizontal, with flaring or without
flaring, and reduced emission completion/workover or not reduced
emission completion/workover. Specifically, for well completions and
workovers with hydraulic fracturing, we are proposing to require
separate counts and separate reporting of emissions for the different
well type combinations. These revisions would improve data quality for
emissions from wells with hydraulic fracturing. Because the EPA is
proposing to expand the well type definition for completions and
workovers with hydraulic fracturing to include whether the well
completions/workovers are flared or not, and whether it is a reduced or
not reduced emission completion/workover, it is possible that reporters
will have more than one reporting category (i.e., different well types
in each sub-basin) for completions and workovers with hydraulic
fracturing. Therefore, some reporters will be required to further
categorize their calculated emissions from completions and workovers
with hydraulic fracturing, which they did not have to do before. We
anticipate that these proposed changes will increase burden to some
reporters somewhat. Reporters will be required to separate and report
their calculated emissions from completions and workovers without
hydraulic fracturing by whether the emissions are related to
completions or workovers, which they do not have to do under the
current version of the rule. We anticipate that those proposed changes
would only slightly increase burden to reporters.
    We are also proposing revisions to Equation W-10A that would add
clarity and increase the accuracy of emissions calculations for gas
well completions and workovers with hydraulic fracturing. In the final
subpart W rule, the measurement or calculation for determining the
ratio of flowback during well completions and workovers to 30-day
production rate in Equation W-10A (40 CFR 98.233(g)) begins immediately
upon initiating flowback of a well. Some reporters have asserted that
the flowback characteristics of a well following hydraulic fracturing
do not enable measurement or calculation to begin immediately upon
initiating flowback due to a lack of sufficient gas being present, and
the calculation needs to be revised to account for this fact.
Therefore, the EPA is proposing to

modify the calculation to require the measurement of flow rate only
when sufficient gas is present to enable flow rate measurement. In
addition, some reporters have asserted that the accuracy of emissions
calculations could be affected by the combined use of sales gas volume
and approximations on flow rates for non-measured wells. To resolve
this apparent issue, the time variable ``Tp'' in Equation W-
10A and W-10B is being modified. Time that the gas is routed to
production would no longer be included, so it would no longer be
necessary to subtract the volume of gas being sent to sales. This
amendment would not significantly change the reporting burden. The
proposed equations are similar in complexity as the previous equations
and use measurements that are of similar complexity. This proposed
revision would improve data quality and provide flexibility by
providing an estimation method for data that could not likely be
measured accurately.
    We are also proposing changes to the calculation section at 40 CFR
98.233(g) and (h) to support the separate calculation of emissions from
completions and workovers that are vented, flared, or use equipment
that separates natural gas from the backflow and sends this natural gas
to a flow-line (e.g., reduced emissions completions or reduced
emissions workovers). Reporters currently calculate emissions from all
completion and workover activities, but the equations do not facilitate
the classification of the activity needed for separate reporting. We
are proposing to revise Equation W-13 in 40 CFR 98.233(h) to separate
the calculation of emissions from workovers from the calculation of
completions into two equations. This amendment will improve data
quality. We are also proposing to clarify that reporters must calculate
the annual volumetric natural gas emissions from each gas well venting
during workovers without hydraulic fracturing using Equation W-13A and
from each gas well venting from completions without hydraulic
fracturing using new Equation W-13B. We do not anticipate that this
proposed change would significantly increase the reporting burden,
because the proposed calculations are the same as the current
calculation; we only propose to break it into two steps. The proposed
methodology also requires the addition of parameter ``Es,p''
for Equation W-13B to specify the annual volumetric natural gas
emissions in standard cubic feet from well completions. We are also
proposing to revise 40 CFR 98.233(g)(1) to clarify the number of
measurements or calculations that must be taken to estimate the average
ratio of flowback rate (FRM).
    We are proposing to revise 40 CFR 98.233(g)(2) to clarify that
measurements from the well flowing pressure upstream of a well choke to
calculate well backflow must be collected for each sub-basin and well
type combination. We are also proposing to revise parameter
``PRs,p'' in Equations W-10A and W-10B and Equation W-12 to
clarify that the first 30 day average production flow rate is the
average taken after completions of newly drilled gas wells or
workovers.
    For further information on gas well venting during completions and
workovers, see the TSD ``Greenhouse Gas Reporting Rule: Technical
Support for Revisions and Confidentiality Determinations for Petroleum
and Natural Gas Systems; Proposed Rule'' in Docket ID No. EPA-HQ-OAR-
2011-0512.
6. Blowdown Vents
    Based on questions received during implementation of the final
subpart W rule and reporter concerns, the EPA is proposing to revise
Equations W-14A and W-14B to include a compressibility term.
Specifically, some reporters requested that the EPA allow the use of a
factor to adjust for compressibility when calculating emissions from
blowdown vents. The calculation method for blowdown vents included in
the existing subpart W rule assumes natural gas is an ideal gas with a
compressibility factor of 1, and does not include an adjustment for
compressibility in the calculation. Although the EPA had previously
considered including the compressibility term (76 FR 56010, September
9, 2011), the EPA ultimately did not propose including the factor,
because we then concluded that including a compressibility adjustment
could create a degree of uncertainty between reporters on how their
reported blowdown values compared (on a volume basis). We noted at that
time that although the compressibility of pure light hydrocarbon
substances is well known, the compressibility of hydrocarbon mixtures
is less well known and the composition of natural gas throughout the
segments covered by subpart W can be variable. At that time, we
determined that ideal gas law calculations were adequate for reporting
purposes under Part 98.
    The EPA notes that the circumstances surrounding this issue are now
different because, as discussed in Section III.B.1 of this preamble,
the EPA is proposing to require the use of site-specific data on gas
compositions, if available. In addition, we have determined that at
high pressures and low temperatures, the accuracy of the emission
estimate would be improved if a compressibility factor were included in
the calculation. The compressibility of methane at standard conditions
is close to one. However, the compressibility of methane at low
temperatures and high pressures is lower than one, which may affect the
accuracy of the emission calculation if not included in that
calculation. Therefore, the EPA proposes to revise Equations W-14A and
W-14B in 40 CFR 98.233(i) to include the compressibility term
``Za''. A default compressibility term of 1 may be used at
conditions where the pressure is below 5 atmospheres, and the
temperature is above -10 degrees Fahrenheit, or if the compressibility
factor at the actual temperature and pressure is 0.98 or greater. We
are proposing harmonizing changes to Equations W-33 and W-34 in 40 CFR
98.233(t) to include the compressibility term ``Za'' for
conversion of volumetric emissions at actual conditions to standard
conditions. Because it is likely that most facilities handle gas within
the proposed compressibility factor default ranges, it is unlikely that
adding this compressibility factor term into the blowdown vent stack
calculations will significantly increase the reporting burden.
    The EPA is also proposing to simplify the reporting for blowdowns.
In the final subpart W rule, reporters must calculate and record
emissions for each blowdown event that is greater than or equal to 50
cubic feet of actual volume. Currently, for each piece of equipment
(unique physical volume) that is blown down more than one time in a
calendar year, reports are submitted for the total number of blowdowns,
the emissions for each unique physical volume, and the name or ID
number for the unique physical volume. For all equipment that is blown
down only once during the calendar year, reports are submitted as an
aggregate for all such equipment at each facility. Reports include the
total number of blowdowns and the emissions from all equipment with
unique physical volumes that are blown down only once. The volume of
gas vented is calculated for each blowdown event using the conditions
specific to the event. However, the reporting of each ``unique physical
volume'' blown down more than once in a year may be an extensive list
of unique equipment.
    A similar reporting approach was adopted by the EPA in the November
2010 version of subpart W (75 FR 74458). There, the reporting

requirement specified that emissions be reported collectively per
equipment type. This approach caused some confusion because a list of
equipment types was not provided. Therefore we are proposing to revise
the current reporting requirements in 40 CFR 98.236(c)(7) to simplify
the reporting structure to report blowdown emissions aggregated by
seven categories: station piping, pipeline venting, compressors,
scrubbers/strainers, pig launchers and receivers, emergency shutdowns,
and all other blowdowns greater than or equal to 50 cubic feet.
Although facilities are no longer required to report blowdown vent
stack emissions by each unique physical volume, facilities still have
to calculate blowdown vent stack emissions from each unique physical
volume and categorize the emissions by equipment. Therefore, the EPA
has determined that this proposed change would not significantly impact
burden to reporters.
    The EPA is also proposing an optional calculation method for
blowdown emissions for situations where a flow meter is in place to
measure the emissions directly. If a blowdown vent is equipped with a
flow meter, there would not be an advantage to calculating the
emissions using the unique volume, temperature, and pressure conditions
of the equipment instead of the directly measured flow rate. We are
proposing this alternative calculation method in 40 CFR 98.233(i),
along with associated reporting requirements in 40 CFR 98.236. We are
also proposing additional clarifying edits for both the blowdown
calculation and reporting sections of the rule. If a flow meter is in
place to measure emissions, the emissions would be reported on a
facility basis, and would not be aggregated by emission type per 40 CFR
98.236(i)(2). For further information on blowdown vents, see the TSD
``Greenhouse Gas Reporting Rule: Technical Support for Revisions and
Confidentiality Determinations for Petroleum and Natural Gas Systems;
Proposed Rule'' in Docket ID No. EPA-HQ-OAR-2011-0512.
7. Onshore Production Storage Tanks
    We are proposing to revise the method for estimating emissions from
occurrences of well pad gas-liquid separator liquid dump valves that
are not properly operating for onshore production storage tanks. The
EPA initiated this revision to address reporter concerns and to improve
data quality. Specifically, reporters expressed concern with the burden
associated with quantifying and recording information for all properly
functioning dump valves. The proposed revisions would require the
detection of an anomaly and only then require quantification. Hence
only those dump valves found to not be closing properly (i.e., stuck
dump valves) would have to be quantified. Specifically, the EPA is
proposing to simplify Equation W-16 to calculate emissions for only
periods when the dump valve is not closing properly.
    The EPA is also proposing to revise the reporting section to make
it clear that facilities are to separately report the emissions from
onshore production storage tanks attributable to periods when dump
valves are not closing properly, as opposed to emissions that occur
when dump valves are closing properly. In the final subpart W rule, 40
CFR 98.236(c)(8)(iv) requires that facilities report annual total
volumetric GHG emissions that resulted from dump valves that are not
closing properly. However, Equation W-16 in the final subpart W rule
sums the total emissions for periods when the dump valve is closing
properly and periods when the dump valve is not closing properly. The
EPA is clarifying 40 CFR 98.236 to specify that facilities that use
Equation W-16 should report only emissions that result from dump valves
that are not closing properly. Note that emissions from atmospheric
tanks that are not a result of dump valves not closing properly would
continue to be reported in this proposed revision outside of Equation
W-16. There is no significant additional burden to facilities, because
reporters already use these data elements in Equation W-16: separate
tank and dump valve emissions already need to be calculated separately,
but would now also be reported separately. This revision would
eliminate potential confusion for reporters, clarify recordkeeping
requirements, and improve the ability to quantify emissions from stuck
dump valves. For further information on emissions from improperly
functioning dump valves, see the TSD ``Greenhouse Gas Reporting Rule:
Technical Support for Revisions and Confidentiality Determinations for
Petroleum and Natural Gas Systems; Proposed Rule'' in Docket ID No.
EPA-HQ-OAR-2011-0512. These proposed revisions would improve the
quality of data collected.
8. Associated Gas Venting and Flaring
    The EPA is proposing to add a term to Equation W-18 (40 CFR
98.233(m)(3)) to account for situations where part of the associated
gas from a well goes to a sales line while another part of the gas is
flared or vented. These amendments improve data quality by eliminating
duplicate reporting. Emissions are currently calculated based on the
gas-to-oil ratio (GOR) and volume of oil produced during the flaring
period. The GOR is based on total gas from the well, which means all
the gas would currently be reported as flared even though a portion of
the gas goes to a sales line. The proposed revision to Equation W-18
subtracts the volume of associated gas sent to sales from the annual
volumetric natural gas emissions from associated gas venting. The EPA
has also included in the equation a term (EREp,q) for
emissions reported under other sources included in this subpart (i.e.,
tank venting) to avoid double counting of these emissions. The EPA also
proposes updating the definition of the term GORp,q and the
emission result Ea,n in Equation W-18 to specify that the
gas to oil ratio and the result of the calculation are calculated at
standard conditions rather than actual conditions. Because the GOR is
measured in standard cubic feet, this change would harmonize the
equation terms and the result of the emission calculation equation
would be at standard conditions. Although the proposed calculation
method modifies the current equation to include two new terms, these
terms are already being calculated elsewhere and/or can be estimated.
Therefore, the EPA does not anticipate that this proposed change will
significantly affect the reporting burden.
    The EPA is also proposing to add a definition for the term
``Associated gas venting or flaring'' to clarify what is included in
this source. The EPA is proposing to define ``Associated gas venting or
flaring'' as ``the venting or flaring of natural gas which originates
at wellheads that also produce hydrocarbon liquids and occurs either in
a discrete gaseous phase at the wellhead or is released from the liquid
hydrocarbon phase by separation. This definition does not include
venting or flaring resulting from activities that are reported
elsewhere, including tank venting, well completions, and well
workovers.'' The proposed definition allows for greater consistency
with the changes made to the calculation method. This is a clarifying
proposed change that improves data quality and should not significantly
affect the burden to current reporters. For further information on
emissions from associated gas, see the TSD ``Greenhouse Gas Reporting
Rule: Technical Support for Revisions and Confidentiality
Determinations for Petroleum and Natural Gas Systems;

Proposed Rule'' in Docket ID No. EPA-HQ-OAR-2011-0512.
9. Flare Stack Emissions
    The EPA is proposing to amend the calculation method for emissions
from a flare stack to simplify the calculation to standard conditions
and to account for gas that is sent to an unlit flare. Specifically, we
are proposing to revise Equation W-19 and combine Equations W-20, and
W-21. The EPA also proposes to revise the equations such that the
emissions of CH4 and CO2 are calculated in
standard conditions. We propose to remove paragraph 40 CFR
98.233(n)(11), which specifies estimating emissions for the volume of
gas flared under actual conditions. We also propose to add the terms
``ZU'' and ``ZL'' to Equation W-19 and the terms
``ZU'' and ``ZL'' to Equation W-20 to account for
the fraction of gas sent to an unlit flare and the fraction of gas sent
to a burning flare. The fraction of feed gas sent to an unlit flare
would be determined by using engineering estimates and process
knowledge. The proposed changes simplify and clarify the calculation
requirements and would improve the accuracy of the collected data by
accounting for the fraction of emissions that are not combusted when
sent to an unlit flare.
    The EPA is also proposing a revision to the onshore natural gas
transmission compression, underground natural gas storage, liquefied
natural gas (LNG) storage, LNG import and export equipment industry
segments to clarify that emissions from any flares in these segments
must be reported using the calculation method for emissions from a
flare stack. This clarifying revision is consistent with the treatment
of flares in other parts of subpart W and is necessary to calculate
emissions for compressors routed to flares under the proposed
compressor calculation requirement modifications. We anticipate that
this proposed change may slightly increase burden for select reporters
and will not significantly affect burden for most reporters; however,
this clarifying revision is consistent with the treatment of flares in
other parts of subpart W and is necessary to calculate emissions for
compressors routed to flares under the proposed compressor calculation
requirement modifications.
10. Centrifugal and Reciprocating Compressors
    Some reporters have contended that the current monitoring
requirements for compressor venting are overly burdensome and present
safety and operational process concerns. These reporters asserted that
it is not practical to require a measurement from each individual
compressor for groups of compressors that are routed to a common vent
manifold (or flare header), because this would require the entire group
of compressors that are connected to the common manifold (or flare
header) to be shutdown, blown down, and purged in order to safely
install meters (or ports for temporary meters) and enable individual
measurements. The reporters stated that it is extremely rare that
entire groups of compressors are shutdown at the same time. In the
November 2010 response to public comments on the subpart W final rule
(Docket ID No. EPA-HQ-OAR-2009-0923), the EPA noted that commenters
requested that the EPA allow direct measurements of common manifolded
vent lines on compressors. At least one commenter stated that if
continuous measurement of manifolded vent lines and aggregate annual
emissions reporting were allowed as an option for measuring
compressors, they would be able to safely collect and report to the EPA
continuously measured data. The EPA did not include this option in the
2010 final subpart W rule because it was not clear whether measurements
at a common vent outlet could be used to correctly characterize annual
emissions from individual compressors.
    In today's action, we are proposing changes to the centrifugal and
reciprocating compressor calculation sections (see 40 CFR 98.233(o) and
(p)) in order to address reporter concerns related to measuring
centrifugal and reciprocating compressor emissions that are routed to a
common vent manifold (or flare header). For those compressors, the EPA
is proposing an option where reporters would take at least three
measurements per year and report the average of the measurements. These
measurements would need to be taken before emissions are comingled with
other non-compressor emission sources. This option would address
reporter's safety concerns for facilities that need to shut down
equipment to install individual meters and maintain accurate
characterization of annual emissions from compressors at the facility.
Annual volumetric emissions would be determined for each manifolded
group of compressors combined for all operating conditions (mode-source
combinations). Reporters would still be required to report activity
data for any individually measured sources (i.e., non-manifolded
sources) at the compressor level. Activity data reported would include
information about the individual compressors included in the manifolded
vent. This proposed measurement option would allow the EPA to correctly
characterize and analyze GHG emissions from all compressors at
individual facilities in the petroleum and natural gas systems source
category while potentially reducing burden to the industry. Although
reporting elements include new activity data, reporters would no longer
be required to sample manifolded compressor sources individually, thus
decreasing overall burden and providing flexibility. For example, if a
reporter operates seven compressors that have their blowdown vent
stacks manifolded, the reporter would no longer have to conduct seven
measurements every year (one for each blowdown vent stack) as required
by the current rule. Instead, for this example, the reporter would be
required to only conduct a measurement three times per year on the
common vent stack that is associated with the manifolded group of seven
compressor sources, which would decrease burden for the reporter
compared to the seven measurements currently required.
    The EPA considered requiring only one or two measurements per year
for these manifolded sources (as opposed to the EPA proposal above for
the average of three measurements). The EPA concluded that the annual
process variability for these sources was high enough to warrant more
than one or two measurements per year. Please see the TSD ``Greenhouse
Gas Reporting Rule: Technical Support for Revisions and Confidentiality
Determinations for Petroleum and Natural Gas Systems; Proposed Rule''
in Docket ID No. EPA-HQ-OAR-2011-0512, for more background and
information on the options considered. In addition to seeking comment
on our proposed option, the EPA is specifically seeking comment on the
two other options that were considered and other derivations of these
options (i.e., four measurements per year instead of three). Comments
should include justification why the specific option receiving comment
does not negatively impact safety, is technical and economically
feasible, does not impose undue burden on reporters, and how the option
is sufficiently accurate given the annual process variability for these
sources.
    We are also proposing to include four definitions in 40 CFR 98.238
to support the addition of the calculation method for manifolded vents.
We are proposing a definition for ``compressor'' to mean ``any type of
vent or valve (i.e., wet seal, blowdown valve, isolation valve, or rod
packing) on a centrifugal or reciprocating compressor.'' We are
proposing a definition for ``compressor

mode'' to mean ``means the operational and pressurized status of a
compressor. For a centrifugal compressor, ``mode'' refers to either
operating-mode or not-operating-depressurized-mode. For a reciprocating
compressor, ``mode'' refers to either: Operating-mode, standby-
pressurized-mode, or not-operating-depressurized-mode.'' We are
proposing a definition for ``manifolded compressor source'' to mean ``a
compressor source that is manifolded to a common vent that routes gas
from multiple compressors.'' We are also proposing a definition of
``manifolded group of compressor sources'' to mean ``a collection of
any combination of compressor sources that are manifolded to a common
vent.''
    In addition, for compressors that are routed to an operational
flare, we are proposing to allow operators to calculate and report
emissions with other flare emissions (in lieu of estimating compressor
emissions based on knowledge of the total flare emissions and the
portion of those flare emissions that can be attributed to
compressors). This proposed change addresses reporter concerns,
provides flexibility, and potentially decreases burden without
affecting data quality. Although operators would still be required to
report certain compressor-related activity data for each compressor
that is routed to an operational flare (as provided for in 40 CFR
98.236(o)(1) and (p)(1)), reporting emissions from compressors (that
are routed to an operational flare) with other flare emissions would
reduce burden, because reporters would not be required to sample
compressors individually or be required to portion flare emissions
attributed to compressors.
    It was brought to the EPA's attention that the 3-year cycle
requirement for measuring compressors in the not-operating-
depressurized-mode could present a compliance challenge for some
facilities, because not every facility schedules routine shutdowns for
maintenance within 3 years. The EPA did not intend for reporters to
perform an unscheduled shutdown of a facility for the sole purpose of
taking a measurement of the compressor in the not-operating-
depressurized-mode. Therefore, we are proposing to revise the
requirement to measure each compressor in the not-operating-
depressurized-mode at least once in any 3 consecutive calendar years,
provided the measurement can be taken during a scheduled shutdown. If
there is no scheduled shutdown within three consecutive calendar years,
the EPA proposes that a measurement must be made at the next scheduled
depressurized compressor shutdown (for reciprocating compressors, this
measurement can be taken during the next scheduled shutdown when the
compressor rod packing is replaced). By allowing the measurement to be
taken at these specified scheduled shutdowns, operators would not have
to plan a shutdown of their equipment to take a measurement of their
compressor in the not-operating-depressurized-mode. This proposed
amendment addresses reporters' concerns and potentially decreases
burden without affecting data quality. Even though the ``not-operating-
depressurized-mode'' is measured only at scheduled shutdowns (which
might be every 3 years or greater), the reporter is still required to
conduct an annual measurement in whatever mode the compressor is found.
Therefore, the frequency in measurements is unchanged. The EPA also
considered modifying the existing requirement to measure each
compressor in the not-operating-depressurized-mode at least once every
3 years to correspond to a longer term, such as every 5 years. However,
such an extension might not resolve the issue for all reporters. The
EPA is specifically seeking comment on our proposed option as well as
the additional option that was considered.
    The EPA is also clarifying that for reporters that elect to conduct
as found leak measurements for individual compressor sources, all
measurements from a single owner or operator may be used when
developing an emission factor (using Equation W-24 or W-28 of 40 CFR
98.233) for each compressor mode-source combination. If the reporter
elects to use this option, the reporter emission factor must be applied
to all reporting facilities for the owner or operator. Although this
option may make it easier for some reporters to keep track of their
calculated reporter emission factors, all reporters are still required
to calculate reporter emission factors if they use the as found leak
measurement option. Therefore, the EPA does not anticipate that this
clarifying edit will significantly affect the reporting burden.
    We are also proposing to restructure and revise the centrifugal and
reciprocating compressor sections (see 40 CFR 98.233(o) and 40 CFR
98.233(p)) in order to improve clarity for reporters. Because the
restructuring was extensive, entirely new text appears for 40 CFR
98.233(o) and 40 CFR 98.233(p). Although the proposed restructuring
changes would not significantly change any of the requirements or
burden, the proposed restructuring and revisions would clarify current
requirements that are vague or confusing. For example, we are proposing
to retain the current equations for determining emissions from each
compressor's measured mode-source combination and unmeasured mode-
source combination; however, we are proposing language that would
explain when to use the equation(s). We are also proposing revisions to
improve consistency between the centrifugal and reciprocating
compressor sections (see 40 CFR 98.233(o) and 40 CFR 98.233(p)). For
example, we are proposing to revise the equation variables to bring
consistency between the two sections. It is our view that the
restructuring and clarification revisions that we are proposing in this
action for the centrifugal and reciprocating compressor sections would
improve readability and usability for both industry and government
regulators. For further information on measuring emissions from
compressors, see the TSD ``Greenhouse Gas Reporting Rule: Technical
Support for Revisions and Confidentiality Determinations for Petroleum
and Natural Gas Systems; Proposed Rule'' in Docket ID No. EPA-HQ-OAR-
2011-0512.
11. Natural Gas Distribution: Leak Detection Equipment and Emissions
From Components
    For natural gas distribution, the final subpart W rule requires
reporters to calculate a facility emission factor for a meter/regulator
run per component type at above grade metering-regulating (M-R)
stations. The calculation of the emission factor using Equation W-32 in
40 CFR 98.233(r) based on the results of equipment leak surveys that
are required under 40 CFR 98.233(q) at above grade transmission-
distribution (T-D) stations and the subsequent annual emissions
calculated for those stations using Equations W-30B. Reporters have
pointed out that the nomenclature and inter-related calculations
between 40 CFR 98.233(q) and (r) has caused confusion. Therefore, the
EPA is proposing to revise the calculation requirements for natural gas
distribution facilities and associated terminology in 40 CFR 98.233(q)
and (r). Specifically, the EPA is proposing to place the facility
meter/regulator run emission factor calculation in 40 CFR 98.233(q)
instead of 40 CFR 98.233(r) and clarify that the emission factor is
calculated separately for CO2 and CH4 and is on a
meter/regulator run operational hour basis, instead of on a meter/
regulator run component basis. Facilities calculate annual emissions
from above grade transmission-distribution transfer stations using
Equation W-30 of 40 CFR 98.233(q).

The emissions are calculated in Equation W-30 on a per component basis
based on equipment leak survey results and leaker emission factors for
transmission-distribution transfer station components listed in Table
W-7. The results of the component level annual emissions calculations
using Equation W-30 are then summed for all component types in Equation
W-31 to develop the annual facility meter/regulator run emission
factors for CO2 and CH4. Those facility emission
factors must be recalculated annually as additional equipment leak
survey data becomes available from above grade transmission-
distribution transfer stations. To calculate annual emissions from
above grade metering-regulating stations that are not above grade
transmission-distribution transfer stations, facilities must use the
emission factors (calculated in Equation W-31) in the annual emissions
calculation of Equation W-32B in 40 CFR 98.233(r). Emissions from below
grade metering-regulating stations, below grade transmission-
distribution transfer stations, distribution mains, and distribution
services are calculated using Equation W-32A of 40 CFR 98.233(r) using
population emission factors listed in Table W-7. These proposed
revisions will alleviate the current confusion with the calculation and
reporting requirements for natural gas distribution facilities while
capturing the same emissions sources from this industry segment and
maintaining the same level of data accuracy. Data are generally
reported at a less detailed level, but there is no change in emissions
coverage.
12. Onshore Petroleum and Natural Gas Production and Natural Gas
Distribution Combustion Emissions
    The EPA is proposing to clarify that emissions and volume of fuel
combusted must be reported for all compressor driven internal
combustion units in 40 CFR 98.236. The EPA is proposing to revise this
reporting requirement to be consistent with the emission estimation
methods in 40 CFR 98.233(z)(4) that specify the exemption from
reporting emissions for internal combustion units with a rated heat
input capacity less than or equal to 1 MMBtu/hr (130 horsepower) does
not apply to internal fuel combustion sources that are compressor
drivers.

C. Proposed Revisions to Missing Data Provisions

    We are proposing to revise 40 CFR 98.235 to clarify the procedures
for estimating missing data. We are proposing to increase the
specificity regarding how to use, treat, and report missing data for
each calculation specified in 40 CFR 98.233.These proposed revisions
would increase clarity for reporters and improve the accuracy of the
data reported by ensuring that the data substituted for missing values
is limited in use, and, where necessary, well-documented and quality-
assured or based on the best available estimates. To address newly
acquired wells, the EPA is also proposing missing data procedures
specific to facilities that are newly subject to subpart W and to
existing onshore petroleum and natural gas production facilities that
acquire wells that were not subject to subpart W prior to the
acquisition. In these specific cases, the EPA is proposing to allow
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. Where
facilities acquired additional wells, only data and calculations
associated with those newly acquired wells would fall within this
proposed provision. This proposed revision provides flexibility for
newly acquired facilities or wells. Missing data procedures were
previously not allowed for many areas of subpart W; however, with the
proposed removal of BAMM, the missing data procedures provide clarity
for reporters who may have unintentionally missed required data.

D. Proposed Amendments to Best Available Monitoring Methods

    In order to provide facilities with time to adjust to the
requirements of the rule, subpart W has provisions allowing the
optional use of best available monitoring methods (BAMM) for unique or
unusual circumstances. Where a facility uses BAMM, it is required to
follow emission calculations specified by the EPA, but is allowed to
use alternative methods for determining inputs to calculate emissions.
Inputs are the values used by facilities to calculate equation outputs.
Examples of BAMM include: Monitoring methods used by the facility that
do not meet the specifications of subpart W, supplier data, engineering
calculations, and other company records. Facilities are required to
receive approval from the EPA prior to using BAMM and these facilities
are required to specify in their GHG annual reports when BAMM is used
for an emission source. The EPA has previously noted that the Agency
intended to ``approve the use of BAMM beyond 2011 only in cases that
are unique or unusual'' (76 FR 59538). Furthermore, the EPA limited the
approvals of BAMM to one reporting year in keeping with the intent to
allow use of BAMM as a transitional provision until facilities come
into compliance with the final rule. While the EPA occasionally uses
BAMM for targeted, short-term monitoring flexibilities (i.e., provision
for reporters who become subject to Part 98 from the recent GWP changes
to subpart A to have automatic BAMM for the first three months of
reporting), no industry-specific subpart within Part 98 continues to
use the BAMM flexibility except subpart W.
    In this action, the EPA is proposing to remove all provisions in 40
CFR 98.234(f) for BAMM. We are also proposing to remove and reserve 40
CFR 98.234(g), which is a provision specific to the 2011 and 2012
reporting years. The removal of BAMM will improve data quality by
requiring consistent reporting for each segment in subpart W. We are
proposing these amendments because we expect facilities would be able
to comply with the monitoring and QA/QC methods required under subpart
W after this proposed rule is finalized and effective. Reporters with
issues that were unidentified at the time of the final rule will, by
January 1, 2015, have had adequate time to resolve these issues. It has
been the EPA's intent throughout implementation of subpart W that BAMM
be available as a limited, transitional program to serve as a bridge to
full compliance with the rule for cases where reporters faced
reasonable impediments to compliance. The EPA never intended to extend
BAMM requirements indefinitely. The proposed amendments are therefore
in keeping with the EPA's stated intent to transition to reporting
without BAMM. We also believe, based on several years of experience
with the industry and these reporting requirements, that facilities
have successfully transitioned so that they either no longer need to
use BAMM or will not need to use BAMM if these proposed revisions are
finalized.
    In a review of BAMM request submittals for the 2014 reporting year,
the EPA found that the sources with the most frequent BAMM requests
included centrifugal compressors, reciprocating compressors, blowdown
vent stacks, and combustion emissions, which are addressed in this
rulemaking. The proposed revisions would also resolve the need for BAMM
for certain facilities for which the final subpart W monitoring
requirements were technically infeasible. For example, the most common
concerns raised in BAMM requests associated with technical
infeasibility included concerns related to having to shut down a
facility to install access ports to

conduct compressor measurements. As discussed in Section II.B.10 of
this preamble, we are making revisions that allow the testing of a
common vent and that clarify that operators do not have to shut a
facility down for the sole purpose to test a compressor in its non-
operating mode, but that the measurement must be made at the next
scheduled shutdown.
    In light of the extended time period in which the EPA has granted
BAMM to allow facilities to come into compliance with subpart W
requirements, the revisions that the EPA is proposing to make to the
final rule, and the fact that all other industry-specific subparts in
Part 98 no longer have continual BAMM, we expect that facilities would
be in compliance with the monitoring and QA/QC methods required under
subpart W for the 2015 calendar year.
    The EPA requests comment and strong technical evidence for site-
specific unique or unusual circumstances that would require the use of
BAMM after January 1, 2015. These comments should include the details
of how and why the special circumstances exist, why the data collection
methods in subpart W (including those in this proposal) are not
feasible, the data that could not be monitored in order to comply with
subpart W, and how specifically the data could otherwise be collected.
For further information on BAMM, see the TSD ``Greenhouse Gas Reporting
Rule: Technical Support for Revisions and Confidentiality
Determinations for Petroleum and Natural Gas Systems; Proposed Rule''
in Docket ID No. EPA-HQ-OAR-2011-0512.

III. Proposed Confidentiality Determinations

A. Overview and Background

    In this proposed rule we are proposing confidentiality
determinations for new and subtantially revised reporting data elements
in the proposed amendments, with certain exceptions as discussed in
more detail below. These new and substantially revised data elements
would result from the proposed corrections, clarifying, and other
amendments that are described in Section II of this preamble, which
would also result in substantial changes to the data elements that are
reported. We are also proposing to revise the confidentiality
determination for one existing data element that is not being amended,
as discussed in Section III.B of this preamble. The final
confidentiality determinations the EPA has previously made for the
remainder of the subpart W data elements are unaffected by the proposed
amendments and continue to apply. For information on confidentiality
determinations for the GHGRP and subpart W data elements, see: 75 FR
39094, July 7, 2010; 76 FR 30782, May 26, 2011; 77 FR 48072, August 13,
2012; and 78 FR 55994, September 11, 2013. These proposed
confidentiality determinations would be finalized after considering
public comment. The EPA plans to finalize these determinations at the
same time the proposed rule amendments described in this action are
finalized.

B. Approach to Proposed CBI Determinations for New or Revised Subpart W
Data Elements

    For the proposed new and substantially revised data elements,
except for the specific data elements separately addressed below, we
are applying the same approach as previously used for making
confidentiality determinations for data elements reported under the
GHGRP. In the ``Confidentiality Determinations for Data Required Under
the Mandatory Greenhouse Gas Reporting Rule and Amendments to Special
Rules Governing Certain Information Obtained Under the Clean Air Act''
(hereinafter referred to as ``2011 Final CBI Rule'') (76 FR 30782, May
26, 2011), the EPA grouped Part 98 data elements into 22 data
categories (11 direct emitter data categories and 11 supplier data
categories) with each of the 22 data categories containing data
elements that are similar in type or characteristics. The EPA then made
categorical confidentiality determinations for eight direct emitter
data categories and eight supplier data categories and applied the
categorical confidentiality determination to all data elements assigned
to the category. Of these data categories with categorical
determinations, the EPA determined that four direct emitter data
categories are comprised of those data elements that meet the
definition of ``emissions data,'' as defined at 40 CFR 2.301(a), and
that, therefore, are not entitled to confidential treatment under
section 114(c) of the CAA.\1\ The EPA determined that the other four
direct emitter data categories and the eight supplier data categories
do not meet the definition of ``emission data.'' For these data
categories that are determined not to be emission data, the EPA
determined categorically that data in three direct emitter data
categories and five supplier data categories are eligible for
confidential treatment as CBI, and that the data in one direct emitter
data category and three supplier data categories are ineligible for
confidential treatment as CBI. For two direct emitter data categories,
``Unit/Process `Static' Characteristics that Are Not Inputs to Emission
Equations'' and ``Unit/Process Operating Characteristics that Are Not
Inputs to Emission Equations,'' and three supplier data categories,
``GHGs Reported,'' ``Production/Throughput Quantities and
Composition,'' and ``Unit/Process Operating Characteristics,'' the EPA
determined in the 2011 Final CBI Rule that the data elements assigned
to those categories are not emission data, but the EPA did not make
categorical CBI determinations for them. Rather, the EPA made CBI
determinations for each individual data element included in those
categories on a case-by-case basis taking into consideration the
criteria in 40 CFR 2.208. No final confidentiality determination was
made for the inputs to emission equation data category (a direct
emitter data category).
---------------------------------------------------------------------------

    \1\ Direct emitter data categories that meet the definition of
``emission data'' in 40 CFR 2.301(a) are Facility and Unit
Identifier Information, Emissions, Calculation Methodology and
Methodological Tier, Data Elements Reported for Periods of Missing
Data that are not Inputs to Emission Equations, and Inputs to
Emission Equations.
---------------------------------------------------------------------------

    For this rulemaking, we are proposing to assign 243 new or revised
data elements to the appropriate direct emitter data categories created
in the 2011 Final CBI Rule based on the type and characteristics of
each data element. Note that subpart W is a direct emitter source
category, thus, no data are assigned to any supplier data categories.
    For data elements the EPA has assigned in this proposed action to a
direct emitter category with a categorical determination, the EPA is
proposing that the categorical determination for the category be
applied to the proposed new or revised data element. For the proposed
categorical assignment of the data elements in these eight categories
with categorical determinations, see Memorandum Data Category
Assignments and Confidentiality Determinations for all Data Elements
(excluding inputs to emission equations) in the Proposed ``Technical
Revisions and Confidentiality Determinations for Petroleum and Natural
Gas Systems'' in Docket ID No. EPA-HQ-OAR-2011-0512.
    For data elements assigned to the ``Unit/Process `Static'
Characteristics that Are Not Inputs to Emission Equations'' and ``Unit/
Process Operating Characteristics that Are Not Inputs to Emission
Equations,'' we are proposing confidentiality determinations on a case-
by-case basis taking into

consideration the criteria in 40 CFR 2.208, consistent with the
approach used for data elements previously assigned to these two data
categories. For the proposed categorical assignment of these data
elements, see Memorandum Data Category Assignments and Confidentiality
Determinations for all Data Elements (excluding inputs to emission
equations) in the Proposed ``Technical Revisions and Confidentiality
Determinations for Petroleum and Natural Gas Systems'' in Docket ID No.
EPA-HQ-OAR-2011-0512. For the results of our case-by-case evaluation of
these data elements, see Sections III.C and III.D of this preamble.
    For the reasons stated below, we are proposing individual
confidentiality deteminations for 11 new or substantially revised data
elements without making a data category assignment. In the 2011 Final
CBI rule, although the EPA grouped similar data into categories and
made categorical confidentiality determinations for a number of data
categories, the EPA also recognized that similar data elements may not
always have the same confidentiality status, in which case the EPA made
individual instead of categorical determinations for the data elements
within such data categories.\2\ Similarly, while the 11 proposed new or
substantially revised data elements are similar in type or certain
characteristics to data elements previously assigned to the
``Production/Throughput Data Not Used as Input'' and ``Raw Materials
Consumed that are Not Inputs to Emission Equations'' data categories,
we do not believe that they share the same confidentiality status as
the non-subpart W data elements already assigned to those two data
categories, which the EPA has determined categorically to be CBI based
on the data elements assigned to those categories at the time of the
2011 Final CBI Rule. As discussed in more detail below, our review
showed that these 11 subpart W production and throughput-related data
elements fail to qualify for confidential treatment. Therefore, we do
not believe that the categorical determinations for the ``Production/
Throughput Data Not Used as Input'' and ``Raw Materials Consumed that
are Not Inputs to Emission Equations'' data categories are appropriate
for these 11 data elements; accordingly, these data elements should not
be assigned to these data categories. Not assigning these 11 data
elements to these two data categories would also leave unaffected the
existing categorical determinations for these data categories, which
remain valid and applicable to the data elements assigned to those data
categories. For the reasons stated above, we are proposing individual
confidentiality determinations for these 11 data elements without
making categorical assignment.
---------------------------------------------------------------------------

    \2\ In the 2011 Final CBI rule, several data categories include
both CBI and non-CBI data elements. See 76 FR 30786.
---------------------------------------------------------------------------

    Our proposed individual determinations follow the same two-step
evaluation process as set forth in the 2011 Final CBI Rule and
subsequent confidentiality determinations for Part 98 data.
Specifically, we first determined whether the data element meets the
definition of emission data in 40 CFR 2.301(a). Data elements that meet
the definition of emission data are required to be released under
section 114 of the Clean Air Act. For data elements found to not meet
the definition of emission data, we evaluated whether a data element
meets the criteria in 40 CFR 2.208 for confidential treatment. In
particular, we focus on: (1) Whether the data are already public; and
(2) whether ``. . . disclosure of the information is likely to cause
substantial harm to the business's competitive position.'' For the
results of our case-by-case evaluation of these proposed new subpart W
data elements, see Section III.D of this preamble.
    We are also proposing to revise the confidentiality determinations
for one existing subpart W data element. Our review of the 11 proposed
data elements discussed above led us to re-examine our previous
determination for this data element, which is similar in type or
characteristics to the 11 proposed data elements for which the EPA is
choosing to make case-by-case determinations. This one data element is
the only subpart W data element currently assigned to ``Production/
Throughput Data Not Used as Input'' data category. As discussed in more
detail in Section III.D of this preamble, our review showed that this
data element fails to qualify for confidential treatment. For the same
reasons set forth above for not proposing categorical assignments for
the 11 data elements, we are proposing to remove this data element's
current category assignment, as well as the application of the
categorical CBI determination to this data element. Instead, we are re-
proposing a confidentiality determination based on the two-step process
discussed above for the proposed 11 new data elements. For the results
of our case-by-case evaluation of the proposed subpart W data elements,
see Section III.D of this preamble.
    We are proposing to assign 40 new or substantially revised data
elements used to calculate GHG emissions in subpart W to the ``Input to
Emission Equation'' data category. To date, the EPA has not made
confidentiality determinations for any data element, including any
subpart W data element, assigned to the ``Inputs to Emission Equation''
data category. We are therefore not proposing confidentiality
determinations for the 40 proposed new or substantially revised inputs
to emission equations data elements. However, due to concerns expressed
by reporters with the potential release of inputs to emission
equations, we previously established a process for evaluating ``inputs
to emission equation'' data elements to identify potential disclosure
concerns and actions to address such concerns if appropriate.\3\ The
EPA has used this process to evaluate inputs to emission equations,
including the subpart W data elements that are already assigned to the
inputs to emission equations data category.\4\ We performed a similar
evaluation for the 40 proposed new and substantially revised subpart W
inputs to emission equations and did not identify any potential
disclosure concerns. Accordingly, the proposal would require reporting
of these data elements by March 31, 2016, which is the reporting
deadline for the 2015 reporting year. For the list of new and revised
subpart W inputs to emission equations and the results of our
evaluation, see memorandum titled ``Review of Public Availability and
Harm Evaluation for Proposed New Inputs to Emission Equations in the
Proposed `Revisions and Confidentiality Determinations for Petroleum
and Natural Gas Systems' '' in Docket ID No. EPA-HQ-OAR-2011-0512.
---------------------------------------------------------------------------

    \3\ See the ``Change to the Reporting Date for Certain Data
Elements Required Under the Mandatory Reporting of Greenhouse Gases
Rule'' (hereinafter referred to as the ``Final Deferral Notice'')
(76 FR 53057, August 25, 2011) and the accompanying memorandum
entitled ``Process for Evaluating and Potentially Amending Part 98
Inputs to Emission Equations'' (Docket ID EPA-HQ-OAR-2010-0929).
    \4\ See the memoranda titled ``Summary of Data Collected to
Support Determination of Public Availability of Inputs to Emission
Equations for which Reporting was Deferred to March 31, 2015'' and
``Evaluation of Competitive Harm from Disclosure of Inputs to
Equations Data Elements Deferred to March 31, 2015.'' (Docket ID
EPA-HQ-OAR-2010-0929).
---------------------------------------------------------------------------

    The proposed amendments include revisions a number of subpart W
data reporting elements for which confidentiality determinations were
previously finalized in the August 13, 2012 ``Final Confidentiality
Determinations for Regulations Under the Mandatory Reporting of
Greenhouse Gases Rule'' (77 FR 48072). The proposed revisions relative
to some of

these data reporting elements would not require different or additional
data to be reported under these data elements. The proposed revisions
include a reorganization of the reporting requirements so that the data
elements more close align with the calculation methodologies. This
reorganization of the reporting section would result in changes to many
of the rule citations for data elements. In addition to re-structuring
the reporting section, the EPA has proposed other minor revisions
designed to clarify the existing reporting requirements. For example,
some of the proposed changes would clarify the source type (e.g.,
natural gas pneumatic device venting, acid gas removal vents, etc.) and
industry segment that is required to report the data element. The
proposed revisions also include corrections of typographical and other
clerical errors. These corrections would not change the data to be
reported. Although the proposed revisions would separate the
requirements into a larger number of discrete reporting elements and
would clarify and correct typographical errors, they would not change
the underlying data elements to be reported for many data elements.
Therefore, the confidentiality determinations finalized in the August
13, 2012 rule continue to apply. We are therefore not proposing
revisions to the existing confidentially determinations for the data
reporting elements that either would not require different or
additional data to be reported under the proposed revisions or the
proposed revisions would not change the underlying data elements to be
reported. For a summary of the proposed reporting requirements for
subpart W that incorporate these changes to data organization and
descriptions, see the memo, ``Proposed Revisions to the Subpart W
Reporting Requirements'' in Docket ID No. EPA-HQ-OAR-2011-0512.

C. Proposed Confidentiality Determinations for Data Elements Assigned
to the ``Unit/Process `Static' Characteristics That Are Not Inputs to
Emission Equations'' and ``Unit/Process Operating Characteristics That
Are Not Inputs to Emission Equations'' Data Categories

    The EPA is proposing to assign 101 proposed new or substantially
revised data elements for subpart W to the ``Unit/Process `Operating'
Characteristics That Are Not Inputs to Emission Equations'' data
category or the ``Unit/Process `Static' Characteristics That Are Not
Inputs to Emission Equations'' data category, because the proposed new
or substantially revised data elements share the same characteristics
as the other data elements previously assigned to the category. We are
proposing confidentiality determinations for these proposed new or
substantially revised data elements based on the approach set forth in
the 2011 Final CBI Rule for data elements assigned to these two data
categories. In that rule, the EPA determined categorically that data
elements assigned to these two data categories do not meet the
definition of emission data in 40 CFR 2.301(a); the EPA then made
individual, instead of categorical, confidentiality determinations for
these data elements.
    As with all other data elements assigned to these two categories,
the proposed new or substantially revised data elements do not meet the
definition of emissions data in 40 CFR 2.301(a). The EPA then
considered the confidentiality criteria at 40 CFR 2.208 in making our
proposed confidentiality determinations. Specifically, we focused on
whether the data are already publicly available from other sources and,
if not, whether disclosure of the data is likely to cause substantial
harm to the business' competitive position. Table 2 of this preamble
lists the data elements the EPA proposes to assign to the ``Unit/
Process `Operating' Characteristics That Are Not Inputs to Emission
Equations'' and ``Unit/Process `Static' Characteristics That Are Not
Inputs to Emission Equations'' data categories, the proposed
confidentiality determination for each data element, and our rationale
for each determination.

   Table 2--Proposed New Data Elements Assigned to the ``Unit/Process
 `Operating' Characteristics That Are Not Inputs to Emission Equations''
   and ``Unit/Process `Static' Characteristics That Are Not Inputs to
                  Emission Equations'' Data Categories
------------------------------------------------------------------------
                                                          Proposed
                                                      confidentiality
           Citation                Data element      determination and
                                                         rationale
------------------------------------------------------------------------
    ``Unit/Process `Operating' Characteristics That Are Not Inputs to
                   Emission Equations'' Data Category
------------------------------------------------------------------------
98.236(d)(1)(iv)..............  Whether any CO2    This proposed data
                                 emissions are      element would be
                                 recovered and      reported by onshore
                                 transferred        petroleum and
                                 outside the        natural gas
                                 facility.          production
                                                    facilities and by
                                                    onshore natural gas
                                                    processing plants.
                                                    This data element
                                                    indicates that a
                                                    facility is
                                                    operating an acid
                                                    gas removal unit and
                                                    indicates how the
                                                    facility handles the
                                                    CO2 emissions it
                                                    generates. Acid gas
                                                    removal units are
                                                    used to remove
                                                    carbon dioxide and
                                                    hydrogen sulfide
                                                    from raw natural gas
                                                    streams and are
                                                    commonly found at
                                                    gas processing
                                                    facilities. These
                                                    units are listed in
                                                    a facility's
                                                    construction and
                                                    operating permits,
                                                    which are publicly
                                                    available. Because
                                                    this information is
                                                    routinely available
                                                    through required
                                                    permits, we propose
                                                    these data elements
                                                    be designated as
                                                    ``not CBI.''

98.236(e)(1)(xvii)............  For each           These proposed data
                                 absorbent          elements would be
                                 dehydrator,        reported by onshore
                                 whether any        petroleum and
98.236(e)(2)(i)...............   dehydrator         natural gas
                                 emissions are      production
                                 vented to the      facilities and by
                                 atmosphere         onshore natural gas
98.236(e)(2)(ii)..............   without being      processing plants.
                                 routed to a        These data elements
                                 flare or           indicate that a
                                 regenerator        facility is equipped
98.236(e)(2)(iii).............   firebox.           with dehydration
                                For glycol          units, the number of
                                 dehydrators with   dehydrators used,
                                 an annual          the design of
                                 average daily      dehydrator used
                                 natural gas        (glycol or
                                 throughput less    desiccant), and how
                                 than 0.4 MMscfd,   emissions from
                                 the total number   dehydration units
                                 of dehydrators     are handled by the
                                 at the facility..  facility.
                                For glycol          Dehydration units
                                 dehydrators with   are used to remove
                                 an annual          water from natural
                                 average daily      gas streams. Most
                                 natural gas        natural gas
                                 throughput less    processing
                                 than 0.4 MMscfd,   facilities are
                                 the total number   equipped with these
                                 of dehydrators     units and because
                                 venting to a       they are a source of
                                 vapor recovery     hazardous air
                                 device..           pollutants, these
                                For glycol          units are subject to
                                 dehydrators with   rigorous emissions
                                 an annual          control requirements
                                 average daily      (e.g., 40 CFR part
                                 natural gas        63, subpart HH).
                                 throughput less    Dehydration units
                                 than 0.4 MMscfd,   and their associated
                                 the number of      control devices are
                                 dehydrators        listed in a
                                 venting to a       facility's
                                 control device     construction and
                                 other than a       operating permits,
                                 vapor recovery     which are publicly
                                 device or a        available. For this
                                 flare or           reason, we propose
                                 regenerator        these data elements
                                 firebox/fire       be designated as
                                 tubes..            ``not CBI'' for both
                                                    onshore production
                                                    and natural gas
                                                    processing plants.
98.236(e)(2)(iv)..............  For glycol
                                 dehydrators with
                                 an annual
                                 average daily
                                 natural gas
                                 throughput less
                                 than 0.4 MMscfd,
                                 whether any
                                 glycol
                                 dehydrator
                                 emissions are
                                 vented to a
                                 flare or
                                 regenerator
                                 firebox/fire
                                 tubes.
98.236(e)(2)(iv)(A)...........  For glycol
                                 dehydrators with
                                 an annual
                                 average daily
                                 natural gas
                                 throughput less
                                 than 0.4 MMscfd
                                 and vented to a
                                 flare or
                                 regenerator
                                 firebox, the
                                 total number of
                                 dehydrators.
98.236(e)(3)(i)...............  For dehydrators
                                 that use
                                 desiccant, the
                                 total number of
                                 dehydrators at
                                 the facility.
98.236(e)(3)(i)...............  For dehydrators
                                 that use
                                 desiccant,
                                 whether any
                                 dehydrator
                                 emissions are
                                 vented to a
                                 vapor recovery
                                 device.
98.236(e)(3)(i)...............  For dehydrators
                                 that use
                                 desiccant, the
                                 total number of
                                 dehydrators
                                 venting to a
                                 vapor recovery
                                 device.
98.236(e)(3)(i)...............  For dehydrators
                                 that use
                                 desiccant,
                                 whether any
                                 dehydrator
                                 emissions are
                                 vented to a
                                 control device
                                 other than a
                                 vapor recovery
                                 device or a
                                 flare or
                                 regenerator
                                 firebox/fire
                                 tubes, and the
                                 control device
                                 type.
98.236(e)(3)(i)...............  For dehydrators
                                 that use
                                 desiccant,
                                 whether any
                                 dehydrator
                                 emissions are
                                 vented to a
                                 control device
                                 other than a
                                 vapor recovery
                                 device or a
                                 flare or
                                 regenerator
                                 firebox/fire
                                 tubes.
98.236(e)(3)(i)...............  For dehydrators
                                 that use
                                 desiccant, the
                                 number of
                                 dehydrators
                                 venting to a
                                 control device
                                 other than a
                                 vapor recovery
                                 device or a
                                 flare or
                                 regenerator
                                 firebox/fire
                                 tubes.
98.236(e)(3)(i)...............  For dehydrators
                                 that use
                                 desiccant,
                                 whether any
                                 glycol
                                 dehydrator
                                 emissions are
                                 vented to a
                                 flare or
                                 regenerator
                                 firebox/fire
                                 tubes.
98.236(e)(3)(i)...............  For dehydrators
                                 that use
                                 desiccant and
                                 vent to a flare
                                 or regenerator
                                 firebox, the
                                 total number of
                                 dehydrators.

98.236(f).....................  Liquids            These proposed data
                                 unloading. You     element would be
                                 must indicate      reported by onshore
98.236(f)(1)(iv)..............   whether well       petroleum and
                                 venting for        natural gas
                                 liquids            production
                                 unloading occurs   facilities. Liquid
                                 at your facility.  unloading is
                                For each Sub-       conducted in mature
                                 basin and well     gas wells that have
                                 tubing diameter    an accumulation of
                                 and pressure       liquids which impede
                                 group for which    the steady flow of
                                 you used           natural gas. This is
                                 Calculation        a common occurrence
                                 Method 1           in reservoirs where
                                 (reported          the pressure is
                                 separately for     depleted and liquids
                                 wells with         enter the well bore.
                                 plunger lifts      The fact that
                                 and wells          liquids unloading
                                 without plunger    occurs and the
                                 lifts), the        number of unloading
                                 count of wells     wells with and
                                 vented to the      without plungers
                                 atmosphere for     vented to the
                                 this grouping..    atmosphere indicate
                                                    that the wells in a
                                                    basin are older and
                                                    may indicate changes
                                                    in production rates.
                                                    However, the age and
                                                    production rates for
                                                    wells are
                                                    information that can
                                                    be derived from or
                                                    are already
                                                    available to the
                                                    public through state
                                                    oil and gas
                                                    commissions. Hence,
                                                    this information is
                                                    routinely publicly
                                                    available, so we
                                                    propose these data
                                                    elements be
                                                    designated as ``not
                                                    CBI.''
98.236(g).....................  Whether the        These proposed data
                                 facility had any   elements would be
                                 gas well           reported by onshore
98.236(g)(3)..................   completions or     petroleum and
                                 workovers with     natural gas
                                 hydraulic          production
                                 fracturing in      facilities and
                                 the calendar       provide information
                                 year.              on whether the
                                For each            facility conducted
                                 completion or      any well completions
                                 workover and       or workovers during
                                 well type          the reporting year,
                                 combination, the   and for those
                                 total number of    facilities that had
                                 completions or     well completions and/
                                 workovers..        or workovers, the
                                                    number of
                                                    completions and
                                                    workovers that were
                                                    completed.
                                                    Information on the
                                                    number of
                                                    completions and
                                                    workovers performed
                                                    by an oil and gas
                                                    operator in a given
                                                    year and the age and
                                                    production rates for
                                                    wells can be derived
                                                    from or is available
                                                    publicly on state
                                                    oil and gas
                                                    commission Web
                                                    sites. Because
                                                    disclosure of these
                                                    data elements would
                                                    not be likely to
                                                    cause substantial
                                                    competitive harm, we
                                                    propose these data
                                                    elements be
                                                    designated as ``not
                                                    CBI.''
98.236(h)(1)..................  You must indicate  This proposed data
                                 whether the        element would be
                                 facility had any   reported by onshore
                                 gas well           petroleum and
                                 completions        natural gas
                                 without            production
                                 hydraulic          facilities and
                                 fracturing or      provides information
                                 any gas well       on whether the
                                 workovers          facility conducted
                                 without            any well completions
                                 hydraulic          or workovers during
                                 fracturing, and    the reporting year
                                 if the             and whether the
                                 activities         emissions were
                                 occurred with or   flared. Information
                                 without flaring.   on completions and
                                                    workovers performed
                                                    in a given year and
                                                    the age and
                                                    production rates for
                                                    wells can be derived
                                                    from or is available
                                                    publicly on state
                                                    oil and gas
                                                    commission Web sites
                                                    and from the Energy
                                                    Information
                                                    Administration
                                                    (EIA). Whether the
                                                    emissions from well
                                                    completions and
                                                    workovers are sent
                                                    to a flare provides
                                                    only information
                                                    about how the
                                                    emissions are
                                                    handled by the
                                                    facility, which is
                                                    not considered to be
                                                    sensitive
                                                    information by the
                                                    industry. Because
                                                    disclosure of these
                                                    data elements would
                                                    not be likely to
                                                    cause substantial
                                                    competitive harm, we
                                                    propose these data
                                                    elements be
                                                    designated as ``not
                                                    CBI.''
98.236(h)(1)(ii)..............  For each sub-      These proposed data
                                 basin with gas     elements would be
                                 well completions   reported by onshore
                                 without            petroleum and
98.236(h)(2)(ii)..............   hydraulic          natural gas
                                 fracturing and     production
                                 without flaring,   facilities and
                                 the number of      provide information
                                 completions that   on the number of
                                 vented gas to      completions where
                                 the atmosphere.    gas is vented to the
                                For each sub-       atmosphere and the
                                 basin with gas     number of
                                 well completions   completions where
                                 without            the gas is vented to
                                 hydraulic          a flare. The number
                                 fracturing with    of completions that
                                 flaring, the       vent gas directly to
                                 number of well     the atmosphere and
                                 completions that   the number of
                                 flared gas..       completions that
                                                    send the gas to a
                                                    flare provides only
                                                    information about
                                                    the number of well
                                                    completions that
                                                    were performed in a
                                                    sub-basin during a
                                                    reporting year and
                                                    how the emissions
                                                    are handled by the
                                                    facility. The number
                                                    of completions
                                                    performed each year
                                                    is available
                                                    publicly on state