[Federal Register Volume 86, Number 10 (Friday, January 15, 2021)]
[Notices]
[Pages 4049-4066]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-00864]



[[Page 4049]]

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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OAR-2020-0351; FRL-10018-10-OAR]


Ozone Transport Commission Recommendation that EPA Require Daily 
Limits for Emissions of Nitrogen Oxides From Certain Sources in 
Pennsylvania

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of Public Hearing and Supplemental Information.

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SUMMARY: The Environmental Protection Agency (EPA) is issuing this 
notice of public hearing and supplemental information regarding a 
recommendation submitted by the Ozone Transport Commission (OTC) to 
address ongoing ozone pollution in the northeastern United States. The 
OTC has recommended that EPA require Pennsylvania to revise its state 
implementation plan (SIP) to include additional control measures that 
would establish daily limits on emissions of nitrogen oxides 
(NOX) from coal-fired electricity generating units (EGUs) 
with already-installed selective catalytic reduction (SCR) or selective 
non-catalytic reduction (SNCR) controls. According to the 
recommendation, the additional control measures are to ensure that the 
SCR and SNCR controls are optimized to minimize NOX 
emissions each day of the ozone season (May 1 through September 30), 
and the measures must be as stringent as any one of several specified 
state rules already approved into the SIPs of Delaware, Maryland, and 
New Jersey. This notice discusses the relevant provisions of the Clean 
Air Act (CAA or the Act), summarizes the recommendation and the 
supporting information submitted by the OTC, and provides additional 
information that EPA believes may be relevant in reaching a decision on 
the recommendation. This notice also announces the date of a public 
hearing and opens a public comment period on the recommendation, the 
supporting information provided by the OTC, and the additional 
information being provided by EPA.

DATES: EPA will hold a virtual public hearing on February 2, 2021. 
Please refer to https://www.epa.gov/interstate-air-pollution-transport/ozone-transport-commission-otc-section-184c-recommendation for 
additional information on the public hearing, including registration 
procedures. Comments must be received on or before March 8, 2021.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2020-0351, at https://www.regulations.gov. Once submitted, comments 
cannot be edited or removed from the docket. EPA may publish any 
comment received to its public docket. Do not submit to EPA's docket at 
https://www.regulations.gov any information you consider to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Multimedia submissions (audio, 
video, etc.) must be accompanied by a written comment. The written 
comment is considered the official comment and should include 
discussion of all points you wish to make. EPA will generally not 
consider comments or comment contents located outside of the primary 
submission (i.e., on the web, cloud, or other file sharing system). For 
additional submission methods, the full EPA public comment policy, 
information about CBI or multimedia submissions, and general guidance 
on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. Please note that to reduce the risk of 
transmitting COVID-19, written comments submitted by mail are 
temporarily suspended, no hand deliveries will be accepted, and EPA is 
temporarily suspending access to its Docket Center and Reading Room for 
public visitors. Additional materials related to this action, including 
submitted comments, can be viewed online at regulations.gov under 
Docket ID No. EPA-HQ-OAR-2020-0351. Our Docket Center staff will 
continue to provide remote customer service via email, phone, and 
webform. For further information and updates on EPA Docket Center 
services, please visit us online at https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Beth Murray, Clean Air Markets 
Division, Office of Atmospheric Programs, Office of Air and Radiation, 
Environmental Protection Agency, 202-343-9115, [email protected].

SUPPLEMENTARY INFORMATION: This document concerns a recommendation 
submitted by the OTC to EPA under CAA section 184(c). In section I, EPA 
discusses the relevant statutory provisions. Section II describes the 
steps EPA is following to facilitate public participation in the 
Agency's process for reaching a decision on the recommendation. In 
Section III, EPA discusses the OTC recommendation, including the 
Delaware, Maryland, and New Jersey rules that OTC believes should 
become the standards for EPA's approval of a responsive SIP revision 
from Pennsylvania. In section III, EPA also identifies the potentially 
affected Pennsylvania EGUs, and summarizes the supporting information 
provided by the OTC. Sections IV and V provide additional information 
on the potentially affected EGUs' historical emissions and on 
regulatory context that may be relevant to EPA's decision on the 
recommendation.
    EPA is holding a public hearing on the recommendation as required 
by section 184(c) and is also taking comment on the recommendation, the 
supporting information submitted by the OTC, and the additional 
information provided by EPA.

I. Statutory Provisions

A. Summary of CAA Section 184

    Ground-level ozone is a secondary air pollutant created by chemical 
reactions between the ozone precursor pollutants NOX and 
volatile organic compounds (VOC) in the presence of sunlight. Precursor 
pollutant emissions can be transported downwind directly or, after 
transformation in the atmosphere, as ozone. Studies have established 
that ozone formation, atmospheric residence, and transport can occur on 
a regional scale (i.e., across hundreds of miles) over much of the 
eastern U.S.\1\
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    \1\ For example, Bergin, M.S. et al. (2007). Regional air 
quality: Local and interstate impacts of NOX and 
SO2 emissions on ozone and fine particulate matter in the 
eastern United States. Environmental Sci. & Tech. 41: 4677-4689.
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    The Ozone Transport Region (OTR) was established by operation of 
law under CAA section 184 and comprises the states of Connecticut, 
Delaware, Maine,\2\ Massachusetts, Maryland, New Hampshire, New Jersey, 
New York, Pennsylvania, Rhode Island, and Vermont, the District of 
Columbia, and the portion of Virginia that is within the Consolidated 
Metropolitan Statistical Area that includes the District of Columbia.
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    \2\ On February 20, 2020, Maine petitioned EPA under CAA section 
176A(a) for removal of certain areas of the state from the OTR. EPA 
has not yet acted on the petition.
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    Under CAA section 184(a), the Administrator established a 
commission for the OTR, the OTC, consisting of the Governor of each 
state or their designee, the Administrator or their designee, the 
Regional Administrators for the EPA regional offices affected (or the 
Administrator's designees), and an air pollution control official 
representing each state in the region, appointed by the Governor. 
Section 184(b) sets forth certain control measures that OTR states are 
required to include in their SIPs, including enhanced vehicle 
inspection and maintenance in certain

[[Page 4050]]

metropolitan statistical areas and implementation of reasonably 
available control technology (RACT) for certain sources of VOC and 
NOX \3\ in the state.
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    \3\ CAA section 184(b) requires RACT for sources of VOC in OTR 
states and CAA section 182(f)(1) extends the requirement for RACT to 
major sources of NOX.
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    CAA section 184(c) specifies a procedure for the OTC to develop 
recommendations for additional control measures to be applied within 
all or a part of the OTR if the OTC determines that such measures are 
necessary to bring any area in the OTR into attainment with national 
ambient air quality standards (NAAQS) for ozone by the applicable 
attainment deadlines. Section 184(c)(1) provides that:

    Upon petition of any states within a transport region for ozone, 
and based on a majority vote of the Governors on the Commission (or 
their designees), the Commission may, after notice and opportunity 
for public comment, develop recommendations for additional control 
measures to be applied within all or a part of such transport region 
if the Commission determines such measures are necessary to bring 
any area in such region into attainment by the dates provided by 
[subpart II of part D of CAA title I].

    Section 184(c) also lays out procedures the Administrator is to 
follow in responding to recommendations from the OTC. After receipt of 
the recommendations, the Administrator is to immediately publish a 
Federal Register notice stating that the recommendations are available 
and is to provide an opportunity for a public hearing within 90 days. 
The Administrator is also to ``commence a review of the recommendations 
to determine whether the control measures in the recommendations are 
necessary to bring any area in such region into attainment by the dates 
provided by [subpart II] and are otherwise consistent with [the Act].'' 
Finally, in undertaking the review, the Administrator is to consult 
with members of the OTC and is to consider the data, views, and 
comments received pursuant to the public hearing.
    CAA sections 184(c)(4) and (5) govern EPA's response to the OTC 
recommendations. Under section 184(c)(4), the Administrator is to 
determine whether to approve, disapprove, or partially approve and 
partially disapprove the recommendations within nine months of receipt. 
For any disapproval or partial disapproval, the Administrator is to 
specify:

    (i) Why any disapproved additional control measures included in 
the recommendation are not necessary to bring any area in such 
region into attainment by the dates provided by [subpart II] or are 
otherwise not consistent with the Act; and
    (ii) Recommendations concerning equal or more effective actions 
that could be taken by the commission to conform the disapproved 
portion of the recommendations to the requirements of [section 184].

    Section 184(c)(5) provides that, upon approval or partial approval 
of any recommendations, the Administrator is to issue, to each state in 
the OTR to which an approved requirement applies, a finding under CAA 
section 110(k)(5) that the SIP for that state is inadequate to meet the 
requirements of CAA section 110(a)(2)(D), often referred to as the 
``good neighbor provision.'' Section 110(a)(2)(D) provides, in 
pertinent part, that each state's SIP shall contain adequate 
provisions:

    (i) Prohibiting, consistent with the provisions of [CAA title 
I], any source or other type of emissions activity within the state 
from emitting any air pollutant in amounts which will--
    (I) Contribute significantly to nonattainment in, or interfere 
with maintenance by, any other state with respect to any [NAAQS].

    Under section 184(c)(5), the Administrator's finding of inadequacy 
under section 110(a)(2)(D) is to require that each affected state 
revise its SIP to include the approved additional control measures 
within one year after the finding is issued.

B. Judicial Interpretation of CAA Section 184(c)

    EPA has taken action under CAA section 184(c) once before. On 
February 10, 1994, the OTC submitted a recommendation under the section 
that EPA require all states in the OTR to adopt a Low Emission Vehicle 
(LEV) program equivalent to the LEV program already adopted by 
California. After proposing to approve the recommendation and 
soliciting public comment, EPA published a final action approving the 
OTC's recommendation and issuing a SIP call that required each OTR 
state either to adopt the LEV program or to adopt other measures of the 
state's choosing that would achieve a level of NOX emission 
reductions identified by EPA. 60 FR 4712 (Jan. 25, 1995). In the final 
action, EPA took the position that authority to promulgate these 
requirements was provided independently by both CAA section 184(c) and 
CAA section 110. Id. at 4716-18.
    On review, the U.S. Court of the Appeals for the District of 
Columbia Circuit (D.C. Circuit) vacated EPA's action. Virginia v. EPA, 
108 F.3d 1397 (D.C. Cir. 1997). Although the court's decision 
ultimately rested on other grounds, the court interpreted certain 
aspects of CAA section 184(c), in part by contrasting it with CAA 
section 110. The court first determined that, as a practical matter, 
the SIP call mandated adoption of the LEV program because the purported 
alternative allowing states to adopt other control measures was so much 
less attractive that it was, in the court's view, ``no alternative at 
all.'' 108 F.3d at 1404. The court then explained that because section 
110 does not authorize EPA to condition approval of a state's SIP on 
the adoption of specific control measures chosen by EPA, section 
110(k)(5) alone could not provide authority for a SIP call requiring 
adoption of the LEV program. Id. at 1410. The court then considered 
whether section 184(c), in contrast to section 110, would allow EPA to 
condition approval of a state's SIP upon the adoption of specific 
control measures and concluded that the language of section 184(c) 
``answers with an emphatic yes.'' Id. However, because the court also 
found that other CAA provisions--specifically, CAA sections 177 and 
202--barred EPA from requiring states to adopt the LEV program at that 
time, the court vacated the SIP call without regard to whether issuance 
of the SIP call otherwise would have been within EPA's authority under 
section 184(c). Id. at 1411-13.\4\
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    \4\ Because its decision rested on other grounds, the court 
found it unnecessary to resolve other claims challenging EPA's 
authority under CAA section 184(c), including claims--contested by 
EPA--that the section is unconstitutional because of the role 
assigned to the OTC. 108 F.3d at 1410.
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C. Options for Action on a CAA Section 184(c) Recommendation

    After the OTC submits a recommendation to EPA, under CAA section 
184(c)(4) the Administrator may approve, disapprove, or partially 
approve and partially disapprove the recommendation. The section's 
requirement that, in conjunction with a disapproval or partial 
disapproval, EPA must identify ``equal or more effective actions that 
could be taken by the commission to conform the disapproved 
recommendation to [CAA section 184]'' suggests that EPA does not have 
authority to simply adopt such conforming modifications on its own 
initiative as part of an action otherwise approving the recommendation. 
We interpret these provisions as limiting the Agency's ability to 
modify or supplement an OTC recommendation, except insofar as EPA may 
partially approve and partially disapprove the recommendation. 
Consistent with the court's discussion in Virginia, this

[[Page 4051]]

statutory interpretation recognizes that, under CAA section 110, EPA 
generally does not have authority to require states to include 
particular control measures in their SIPs, and that section 184(c) 
provides a limited exception to this general principle only with 
respect to control measures that have been specifically recommended to 
EPA by the OTC in accordance with statutory procedures.
    EPA requests comment on this interpretation of its options for 
action on the OTC's recommendation.
    EPA also requests comment on the standard that should be applied in 
acting on the OTC's recommendation. CAA sections 184(c)(2)(B) and 
(c)(4)(i) provide that EPA is to determine whether the OTC's 
recommended additional control measures are ``necessary to bring any 
area in [the OTR] into attainment by the [areas' attainment dates].'' 
However, CAA section 184(c)(5) states that where the EPA approves or 
partially approves the OTC's recommendation, the Administrator is to 
issue a finding under CAA section 110(k)(5) that the state at issue 
(here, Pennsylvania) has an implementation plan inadequate to meet the 
requirements of CAA section 110(a)(2)(D). In effect, this would be a 
determination that the plan does not contain adequate provisions 
prohibiting emissions in amounts which will contribute significantly to 
nonattainment in, or interfere with maintenance by, any other state 
with respect to a NAAQS. EPA invites comment on how it should interpret 
these provisions in order to ensure consistent treatment throughout the 
section 184(c) process.

II. Public Notice and Participation Under CAA Section 184(c)

    As noted in section I.A of this document, CAA section 184(c)(1) 
requires the OTC to provide notice and an opportunity for public 
comment on any recommendations for additional control measures to be 
applied within all or part of the OTR. After the OTC transmits such 
recommendations to EPA, EPA is to publish a notice stating that the 
recommendations are available, hold a public hearing, consult with 
members of the OTC, conduct a review of the OTC recommendation, and 
issue an approval, disapproval, or partial approval and partial 
disapproval of the recommendation within nine months of receiving the 
recommendation. CAA section 184(c)(1)-(4). The CAA requires that EPA 
publish its determination in the Federal Register.
    The provision also requires that EPA ``shall take into account the 
data, views, and comments received'' pursuant to its notification of 
the available recommendation and the public hearing. EPA is in this 
notice providing information the Agency has developed and that it is 
considering in light of the OTC's recommendation, and we are providing 
an opportunity for the public to submit comments on the OTC's 
recommendation and this information by March 8, 2021. This opportunity 
to comment is in addition to the statutorily mandated public 
hearing.\5\
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    \5\ We note that in EPA's only prior action on a section 184(c) 
recommendation in 1994-1995, the Agency elected to employ CAA 
section 307(d) rulemaking procedures in acting on the OTC's 
recommendation, but stated that it was not legally obligated to do 
so. See 80 FR 21270, 21274 (Apr. 26, 1994).
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    Specifically, EPA seeks public comments on the OTC's 
recommendation; the information the OTC submitted to EPA in support of 
its recommendation, consisting of certain technical analyses and a 
summary of OTC's response to the comments submitted to the OTC; and the 
information EPA is providing in this document and in other materials 
referenced in this document and included in the docket established for 
this action.
    As discussed elsewhere in this document, EPA is considering several 
issues in determining whether to approve or disapprove the OTC 
recommendation and invites comments on all these issues. In addition to 
providing the opportunity to file written comments and present oral 
views at the February 2, 2021 hearing, EPA intends to consult with the 
affected states as required by section 184(c)(3) prior to making a 
final decision on the recommendation. If EPA approves or partially 
approves the OTC's recommendation, per CAA section 184(c)(5), the 
Agency shall issue a finding under CAA section 110(k)(5), also known as 
a SIP call, that the implementation plan for such state is inadequate 
to meet the requirements of CAA section 110(a)(2)(D).

III. Discussion of the OTC's Recommendation

A. The OTC's Section 184(c) Recommendation for NOX Limits on 
Certain Pennsylvania EGUs

    In 2015, EPA revised the NAAQS for ozone to 70 parts per billion 
(ppb). 80 FR 65292 (October 28, 2015). In 2018, EPA designated certain 
areas as nonattainment with respect to this NAAQS and identified each 
area's classification according to the severity of its air quality 
problems. 83 FR 25776 (June 4, 2018). Five areas within the OTR were 
designated as nonattainment: Baltimore, MD; Greater Connecticut, CT; 
Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE; Washington, DC-MD-
VA; and New York-Northern New Jersey-Long Island, NY-NJ-CT. Id. The 
first four of these areas were classified as Marginal and the New York 
area was classified as Moderate. Id. The attainment deadlines for the 
Marginal and Moderate areas are three and six years after the effective 
date of their nonattainment designations, or August 3, 2021 and August 
3, 2024, respectively. 83 FR 10376 (March 9, 2018).
    On May 30, 2019, Maryland petitioned the OTC to adopt a 
recommendation calling for additional control measures to be applied 
within part of the OTR. In response to Maryland's petition, the OTC 
commenced a notice-and-comment process that culminated in a June 3, 
2020 vote by a majority of OTR states to submit a recommendation to EPA 
under CAA section 184(c).\6\ EPA received the recommendation on June 8, 
2020 and published a notice in the Federal Register of the availability 
of the recommendation on July 13, 2020 (85 FR 41974). The 
recommendation itself is published as an appendix to this document, and 
the recommendation as well as the supporting materials submitted to EPA 
by the OTC are available in the docket.
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    \6\ The supporting materials submitted by the OTC include 
documentation that notice-and-comment procedures were followed. See 
Part 3 of Attachment 2, ``Policy and Technical Rationale Supporting 
OTC's Recommendation for Additional Control Measures Under CAA 
Section 184(c),'' and Attachment 3, ``Response to Comments Received 
on OTC 184(c) Recommendation,'' available in the docket.
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    The OTC has recommended that EPA require Pennsylvania to revise its 
SIP to establish daily NOX emissions limits for coal-fired 
EGUs with existing SCR or SNCR controls to ensure optimization of the 
controls to minimize NOX emissions each day of the ozone 
season. The recommendation calls for the new Pennsylvania requirements 
to be as stringent as the requirements in any one of certain existing 
rules adopted by Delaware, Maryland, and New Jersey that were 
incorporated by reference into the recommendation. Each of the 
referenced rules was intended to establish some form of daily 
NOX control requirements for the respective state's coal-
fired EGUs. The recommendation requests that EPA require Pennsylvania 
to implement the requested control measures as

[[Page 4052]]

expeditiously as practicable.\7\ The OTC recommendation did not address 
sources other than coal-fired EGUs in Pennsylvania.
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    \7\ The recommendation also specifically requests that EPA 
require Pennsylvania to establish daily NOX limits for 
the 2020 and 2021 ozone seasons.
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    The OTC highlighted four main reasons for making the 
recommendation. First, several areas in the OTR are not expected to 
attain the 2015 ozone NAAQS by 2021, the statutory deadline for areas 
classified as Marginal. If the areas do not attain by the deadline, 
they will be reclassified (i.e., ``bumped up'') and subject to more 
stringent requirements. Additionally, there are still some areas that 
have not attained the 2008 ozone NAAQS. The OTC's second line of 
reasoning points to research showing that large regional NOX 
reductions lower peak ozone across the eastern U.S. and that additional 
NOX reductions are needed for attainment of the 2008 and 
2015 ozone NAAQS. Third, the OTC references EPA information identifying 
emissions from Pennsylvania as contributing to downwind nonattainment 
and includes estimates developed by Maryland of additional 
NOX reductions from Pennsylvania EGUs that could be achieved 
through daily NOX limits. Finally, the OTC states that it 
decided to use the CAA section 184(c) process after a collaborative 
process resulted in some states adopting daily NOX limits, 
while Pennsylvania, with the largest NOX emissions from 
coal-fired EGUs of any state in the OTR, has not.
    In the cover letter accompanying the recommendation, the OTC 
recognizes that Pennsylvania has a regulatory process underway to 
update its RACT requirements for the EGUs that are the subject of the 
recommendation (Pennsylvania calls the planned requirements ``RACT 
III''). Pennsylvania has periodically provided the OTC with information 
on the progress and components of the RACT III regulatory process. The 
OTC's letter states that the OTC will withdraw the CAA section 184(c) 
recommendation if Pennsylvania adopts final RACT III requirements that 
address the recommendation.

B. Pennsylvania Units Affected by the Recommendation

    EPA has identified the operating Pennsylvania coal-fired EGUs 
(including units that combust coal refuse) that are believed to have 
already installed SCR controls (10 units) or SNCR controls (8 units) 
and that therefore would be affected by a full approval of the OTC's 
recommendation. Table III-1 lists the units and indicates for each unit 
the associated generator capacity, boiler type, and NOX 
control type as well as NOX mass emissions and 
NOX emission rate for the 2019 ozone season. In Table III-2, 
EPA lists operating Pennsylvania coal-fired EGUs that are believed not 
to have already installed SCR or SNCR controls. The two tables exclude 
units that are believed to have either retired or permanently 
discontinued coal combustion.
    EPA requests comment on whether the Pennsylvania units that would 
be affected by a full approval of the OTC's recommendation have been 
correctly identified.

             Table III-1--Pennsylvania Operating Coal-Fired EGUs With SCR or SNCR Controls [dagger]
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                                                                                    2019 ozone      2019 ozone
                                  Generator                      Post-combustion    season NOX      season NOX
             Unit                  summer         Boiler type      NOX controls      emissions     emission rate
                                capacity (MW)                                         (tons)        (lb/mmBtu)
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Cheswick unit 1..............             565  Tangential......  SCR............             331           0.192
Colver unit AAB01............             110  Fluidized bed...  SNCR...........             309           0.157
Conemaugh unit 1.............             850  Tangential......  SCR............           1,350           0.132
Conemaugh unit 2.............             850  Tangential......  SCR............           1,719           0.149
Homer City unit 1............             623  Dry bottom wall.  SCR............             504           0.106
Homer City unit 2............             633  Dry bottom wall.  SCR............             465           0.107
Homer City unit 3............             650  Dry bottom wall.  SCR............             456           0.089
Keystone unit 1..............             850  Tangential......  SCR............           1,778           0.136
Keystone unit 2..............             850  Tangential......  SCR............           1,368           0.134
Montour unit 1...............             752  Tangential......  SCR............             143           0.101
Montour unit 2...............             752  Tangential......  SCR............             120           0.106
Northampton unit NGC01.......             112  Fluidized bed...  SNCR...........              12           0.075
Panther Creek unit 1.........  [dagger][dagge  Fluidized bed...  SNCR...........               3           0.123
                                        r] 83
Panther Creek unit 2.........  [dagger][dagge  Fluidized bed...  SNCR...........               5           0.116
                                        r] 83
Scrubgrass unit 1............  [dagger][dagge  Fluidized bed...  SNCR...........              52           0.118
                                        r] 85
Scrubgrass unit 2............  [dagger][dagge  Fluidized bed...  SNCR...........              53           0.131
                                        r] 85
Seward unit 1................  [dagger][dagge  Fluidized bed...  SNCR...........             107           0.095
                                       r] 521
Seward unit 2................  [dagger][dagge  Fluidized bed...  SNCR...........              91           0.088
                                       r] 521
                              ----------------------------------------------------------------------------------
    Totals/Wtd. average (all            8,286  ................  ...............           8,866           0.129
     units).
                              ----------------------------------------------------------------------------------
    Totals/Wtd. average (SCR-           7,375  ................  ...............           8,233           0.130
     equipped units).
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[dagger] Data sources: EPA Clean Air Markets, Power Sector Emissions Data, Air Markets Program Data (AMPD) and
  EIA Form 860. ``Coal-fired'' EGUs include units combusting coal refuse. Several of the units report ``ammonia
  injection'' controls which EPA interprets as SNCR controls.
[dagger][dagger] This generator is served by multiple boilers.


[[Page 4053]]


            Table III-2--Pennsylvania Operating Coal-Fired EGUs Without SCR or SNCR Controls [dagger]
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                                                                                    2019 ozone      2019 ozone
                                  Generator                      Post-combustion    season NOX      season NOX
             Unit                  summer         Boiler type      NOX controls      emissions     emission rate
                                capacity (MW)                                         (tons)        (lb/mmBtu)
----------------------------------------------------------------------------------------------------------------
Brunner Island unit 1                     306  Tangential......  none...........             176           0.121
 [dagger][dagger].
Brunner Island unit 2                     363  Tangential......  none...........             115           0.103
 [dagger][dagger].
Brunner Island unit 3                     742  Tangential......  none...........             283           0.109
 [dagger][dagger].
Ebensburg unit 031...........              50  Fluidized bed...  none...........              83           0.079
Gilberton unit 031...........  [dagger][dagge  Fluidized bed...  none...........              62           0.071
                                        r] 80
Gilberton unit 032...........  [dagger][dagge  Fluidized bed...  none...........              62           0.072
                                        r] 80
Mt. Carmel unit SG-101.......              43  Fluidized bed...  none...........              23           0.069
St. Nicholas unit 1..........              86  Fluidized bed...  none...........             110           0.052
Westwood unit 031............              30  Fluidized bed...  none...........              61           0.132
                              ----------------------------------------------------------------------------------
    Totals/Wtd. average......           1,700  ................  ...............             976           0.090
----------------------------------------------------------------------------------------------------------------
[dagger] Data sources: EPA Clean Air Markets, Power Sector Emissions Data, Air Markets Program Data (AMPD) and
  EIA Form 860. ``Coal-fired'' EGUs include units combusting coal refuse.
[dagger][dagger] Reported data indicate that this unit combusted primarily natural gas during the 2019 ozone
  season.
[dagger][dagger][dagger] This generator is served by multiple boilers.

C. Referenced State Rules for Delaware, Maryland, and New Jersey

    As noted in section III.A of this document, the OTC's 
recommendation calls for EPA to require Pennsylvania to adopt 
requirements into its SIP that are at least as stringent as the 
requirements in referenced state rules adopted by Delaware, Maryland, 
or New Jersey.\8\ Following approval or partial approval of the OTC's 
recommendation, EPA would be required to issue a SIP call, and 
Pennsylvania would be required to submit a responsive SIP revision 
within one year. In order to approve the SIP revision, if EPA were to 
approve the recommendation in full, EPA would then need to determine 
whether the requirements adopted by Pennsylvania in response to the 
resulting SIP call in fact are at least as stringent as the 
requirements previously adopted by one of the other three states. These 
three referenced rules are therefore important components of the OTC's 
recommendation, because the rules provide the only benchmark for 
comparison against which EPA would determine the approvability of a 
future submission from Pennsylvania. In this section, EPA summarizes 
the relevant provisions of the Delaware, Maryland, and New Jersey state 
rules and requests comment on how EPA would use the rules as standards 
for determining whether a SIP revision submitted by Pennsylvania is 
approvable.
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    \8\ EPA has already approved the three referenced state rules 
into the respective states' SIPs. See Delaware SIP approval (73 FR 
50723, Aug. 28, 2008; 75 FR 48566, Aug. 11, 2010); Maryland SIP 
approval (82 FR 24546, May 30, 2017); New Jersey SIP approval (83 FR 
50506, Oct. 9, 2018).
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1. Delaware
    The Delaware rule referenced in the OTC's recommendation is 7 DE 
Admin. Code 1146, Electric Generating Unit (EGU) Multi-Pollutant 
Regulation. Section 4.3 requires each existing coal-fired and residual 
oil-fired EGU with a nameplate capacity rating of 25 MW or more to 
limit its NOX emission rate to 0.125 lb/mmBtu on a 24-hour 
rolling average basis. The rule does not differentiate among EGUs based 
on the type of boiler or control technology and contains no exceptions 
based on load levels or particular operating conditions (such as start-
up or shut-down). Delaware has one operating coal-fired EGU. The unit 
is equipped with SCR controls.

                            Table III-3--Delaware Operating Coal-Fired EGUs [dagger]
----------------------------------------------------------------------------------------------------------------
                                                                                    2019 ozone      2019 ozone
                                  Generator                      Post-combustion    season NOX      season NOX
             Unit                  summer         Boiler type      NOX controls      emissions     emission rate
                                capacity (MW)                                         (tons)        (lb/mmBtu)
----------------------------------------------------------------------------------------------------------------
Indian River unit 4..........             410  Dry bottom turbo  SCR............              48           0.082
----------------------------------------------------------------------------------------------------------------
[dagger] Data sources: EPA Clean Air Markets, Power Sector Emissions Data, Air Markets Program Data (AMPD) and
  EIA Form 860.

2. Maryland
    The Maryland rule referenced in the OTC's recommendation is COMAR 
26.11.38, Control of Nitrogen Oxide Emissions from Coal-Fired Electric 
Generating Units. Maryland's rule establishes requirements that vary 
across units as well as groups of units under common ownership, with 
differences that appear to reflect factors including boiler type, 
control technology, and other characteristics of individual units.
    One of Maryland's operating coal-fired EGUs is a fluidized bed 
boiler equipped with SNCR controls. Section .03D(2) requires this unit 
to limit its NOX emissions to 0.10 lb/mmBtu on a 24-hour 
block average basis without any exceptions based on load levels or 
operating conditions (such as start-up or shut-down). There is little 
overlap between the requirements established for this unit and the 
requirements established for other Maryland coal-fired EGUs under the 
referenced rule.

[[Page 4054]]

    Maryland's seven other operating coal-fired EGUs are tangentially 
fired or dry bottom wall-fired boilers, six of which are equipped with 
SCR and one of which is equipped with another type of ammonia-based 
post-combustion NOX control.\9\ For these units, the rule 
establishes a multi-part set of ozone season requirements. First, 
section .03A(1) requires the owner of each unit to submit for approval 
a plan addressing how the unit's NOX controls will be 
operated under various possible operating conditions. Second, section 
.03A(2) requires each of these EGUs ``to minimize NOX 
emissions by operating and optimizing the use of all installed 
pollution control technology and combustion controls consistent with 
the technological limitations, manufacturers' specifications, good 
engineering and maintenance practices, and good air pollution control 
practices for minimizing emissions (as defined in 40 CFR 60.11(d)) for 
such equipment and the unit at all times the unit is in operation while 
burning any coal.'' Third, section .03B(1) limits owner-level average 
NOX emission rates to 0.15 lb/mmBtu on a 30-day rolling 
average basis. (Depending on the owner's choice of compliance options 
for its units without SCR controls under section .04, the owner-level 
30-day rolling average emission rate limit may be phased down to 0.09 
lb/mmBtu by 2020.) Fourth, section .03C incorporates a set of unit-
level and owner-level caps on ozone season NOX mass 
emissions established under COMAR 26.11.27. Fifth, section .04 requires 
that by June 1, 2020 each coal-fired unit not already equipped with SCR 
controls (except the fluidized bed unit) either install SCR controls, 
retire, switch to natural gas combustion, or, in conjunction with the 
owner's other units, meet either an owner-level daily NOX 
emission rate limit of 0.13 lb/mmBtu or an owner-level daily cap on 
NOX mass emissions of 21 tons.\10\
---------------------------------------------------------------------------

    \9\ Chalk Point unit 2 is equipped with selective autocatalytic 
reduction (SACR) controls. SACR controls use simultaneous injections 
of ammonia and hydrocarbons (e.g., natural gas) to create a 
catalytic chemical reaction that reduces NOX without a 
separate catalyst. See https://www.nsenergybusiness.com/features/featuresacr-promises-low-nox-at-low-cost/ (March 5, 2002).
    \10\ At the time Maryland adopted COMAR 26.11.38, section .04 
applied to seven coal-fired units without SCR controls. Chalk Point 
unit 2 is the only one of these seven EGUs that is still operating 
as a coal-fired unit.
---------------------------------------------------------------------------

    Finally, in addition to the plans, operational standards and 
limits, and control requirements of the rules, section .05 establishes 
compliance demonstration requirements, including detailed daily 
reporting requirements that apply for days on which affected units 
exceed specified benchmark 24-hour block average NOX 
emission rates. For the SCR-equipped units, each unit is assigned a 
unit-specific benchmark NOX emission rate of 0.07 or 0.08 
lb/mmBtu, one unit is also assigned a second unit-specific benchmark 
rate of 0.15 lb/mmBtu that applies at lower load levels, and one unit 
is also assigned an alternative facility-wide benchmark rate in 
conjunction with a co-located unit that does not have SCR controls. For 
the units not equipped with SCR controls (except the fluidized bed 
unit), each unit is assigned a unit-specific benchmark rate ranging 
from 0.24 to 0.34 lb/mmBtu and several units are also assigned 
alternative facility-wide benchmark rates. Section .05A(4) generally 
provides that exceedances of the benchmark NOX emission 
rates are not violations of the requirement under section .03A(2) to 
operate and optimize installed controls as long as the owner has 
followed its approved plan for operating and optimizing the controls 
under section .03A(1).

                            Table III-4--Maryland Operating Coal-Fired EGUs [dagger]
----------------------------------------------------------------------------------------------------------------
                                                                                    2019 ozone      2019 ozone
                                  Generator                      Post-combustion    season NOX      season NOX
             Unit                  summer         Boiler type      NOX controls      emissions     emission rate
                                capacity (MW)                                         (tons)        (lb/mmBtu)
----------------------------------------------------------------------------------------------------------------
Brandon Shores unit 1........             635  Dry bottom wall.  SCR............             235           0.064
Brandon Shores unit 2........             638  Dry bottom wall.  SCR............             299           0.065
Chalk Point unit 1                        333  Dry bottom wall.  SCR............             105           0.133
 [dagger][dagger].
Chalk Point unit 2                        337  Dry bottom wall.  SACR...........             129           0.189
 [dagger][dagger].
Morgantown unit 1............             596  Tangential......  SCR............             108           0.046
Morgantown unit 2............             609  Tangential......  SCR............             122           0.039
Wagner unit 3................             305  Dry bottom wall.  SCR............              17           0.069
Warrior Run unit 001.........             180  Fluidized bed...  SNCR...........             184           0.066
                              ----------------------------------------------------------------------------------
    Totals/Wtd. average (all            3,633  ................  ...............           1,198           0.066
     units).
                              ----------------------------------------------------------------------------------
    Totals/Wtd. average (SCR-           3,116  ................  ...............             885           0.060
     equipped units).
----------------------------------------------------------------------------------------------------------------
[dagger] Data sources: EPA Clean Air Markets, Power Sector Emissions Data, Air Markets Program Data (AMPD) and
  EIA Form 860.
[dagger][dagger] This unit has a proposed retirement date of June 1, 2021. See https://www.genon.com/genon-news/genon-holdings-inc-announces-retirement-of-chalk-point-coal-units (August 10, 2020).

3. New Jersey
    The New Jersey rule referenced in the OTC's recommendation is 
N.J.A.C. 7:27-19.4, Control and Prohibition of Air Pollution from 
Oxides of Nitrogen: Boilers serving electric generating units. Under 
section 19.4(a), each existing coal-fired EGU is required to limit 
NOX emissions during the ozone season to 1.50 lb/MWh.\11\ 
Section 19.4(d) incorporates the provisions of N.J.A.C. 7:29-19.15(a), 
which generally require EGUs to demonstrate compliance with this 
emission rate limit on a 24-hour block average basis during the ozone 
season. Under section 19.4(e), emissions occurring during certain 
start-up and shut-down hours when a unit is not combusting coal may be 
excluded from the emission rate calculations. The rule does not 
differentiate among EGUs based on the type of boiler or control 
technology. New Jersey has three operating coal-fired EGUs, all of 
which are equipped with SCR controls.
---------------------------------------------------------------------------

    \11\ For units with heat rates of 9,000, 10,000, and 11,000 Btu/
kWh, an emission rate limit expressed as 1.5 lb/MWh would be 
equivalent to emission rate limits expressed as 0.167, 0.150, and 
0.136 lb/mmBtu, respectively.

[[Page 4055]]



                           Table III-5--New Jersey Operating Coal-Fired EGUs [dagger]
----------------------------------------------------------------------------------------------------------------
                                                                                    2019 ozone      2019 ozone
                                  Generator                           Post-         season NOX      season NOX
             Unit                  summer         Boiler type     combustion NOX     emissions     emission rate
                                capacity (MW)                        controls         (tons)        (lb/mmBtu)
----------------------------------------------------------------------------------------------------------------
Carneys Point unit 1001......  [dagger][dagge  Dry bottom wall.  SCR............             110           0.102
                                       r] 244
Carneys Point unit 1002......  [dagger][dagge  Dry bottom wall.  SCR............              90           0.098
                                       r] 244
Logan unit 1001..............             219  Dry bottom wall.  SCR............             160           0.119
                              ----------------------------------------------------------------------------------
    Totals/Wtd. average......             463  ................  ...............             360           0.108
----------------------------------------------------------------------------------------------------------------
[dagger] Data sources: EPA Clean Air Markets, Power Sector Emissions Data, Air Markets Program Data (AMPD) and
  EIA Form 860.
[dagger][dagger] This generator is served by multiple boilers.

D. Use of the Delaware, Maryland, and New Jersey Rules as Standards for 
Evaluating a Pennsylvania SIP Submission

    Under the OTC's recommendation, Pennsylvania would be required to 
revise its SIP to include control measures establishing daily 
NOX emission limits that ensure optimization of existing SCR 
and SNCR controls and that are at least as stringent as the 
requirements for Delaware, Maryland, or New Jersey EGUs described 
above. The diversity of the other states' rules provides Pennsylvania 
with flexibility in designing its responsive SIP revision but the lack 
of precise specifications for the required additional control measures 
also raises the possibility that EPA would not have an objectively 
clear standard for determining whether the SIP revision would in fact 
comply with the OTC's recommendation.
    The Delaware and New Jersey rules--and the Maryland rule as applied 
to one EGU--establish binding daily NOX emission rate limits 
but do not appear to require operation or optimization of installed 
NOX controls. Also, the stringencies of the daily 
NOX emission rate limits differ across the three states, and 
the rules do not contain information indicating whether or how the 
physical or operating characteristics of each state's units might have 
been considered for purposes of setting the stringency of that state's 
emission rate limits.
    In contrast, Maryland's rule--as applied to all but one of the 
state's coal-fired EGUs--requires daily operation and optimization of 
installed NOX controls but does not establish binding daily 
NOX emission rate limits, although it does establish non-
binding benchmark daily NOX emission rates. In addition, 
while variations in the benchmark rates across units indicate that some 
unit-specific characteristics were considered when setting those rates, 
the rule does not contain information indicating how such 
characteristics were considered.
    EPA requests comment on whether the Delaware, Maryland, and New 
Jersey rules have been accurately summarized in this document. EPA also 
requests comment on how those rules could be used as standards for 
evaluating a SIP revision submitted by Pennsylvania, including but not 
limited to the following questions:
     If Pennsylvania establishes requirements for daily 
NOX emission rate limits that are at least as stringent as 
those in Delaware's rule or New Jersey's rule, could the SIP revision 
be approved if it does not also establish requirements to operate and 
optimize installed NOX controls? Alternatively, if 
Pennsylvania establishes requirements to operate and optimize controls 
comparable to Maryland's rule for the majority of its sources, could 
the SIP revision be approved if it does not also establish binding 
daily NOX emission rate limits or benchmark daily 
NOX emission rates?
     If Pennsylvania's SIP revision would have to establish 
binding daily NOX emission rate limits or benchmark daily 
NOX emission rates, could those limits or benchmark rates be 
higher than the limits or benchmark rates set by Delaware, Maryland, 
and New Jersey if supported by differences in the physical or operating 
characteristics of the coal-fired units in the respective states? 
Conversely, would EPA need to consider whether Pennsylvania could have 
set limits or benchmark rates lower than the limits or benchmark rates 
set by the other states based on differences in the units' physical or 
operating characteristics?
     Are there other ways in which EPA could consider 
differences in the physical or operating characteristics of 
Pennsylvania's coal-fired EGUs relative to the other states' EGUs when 
evaluating a responsive Pennsylvania SIP revision? For example, could 
EPA approve a SIP revision that exempts or establishes less stringent 
control requirements for Pennsylvania EGUs whose unit sizes (e.g., MW 
capacity) or historical emissions fall below the ranges of unit sizes 
or historical emissions for the other states' units?
     Is EPA's authority under section 184(c) to modify the 
OTC's recommendation limited such that when evaluating Pennsylvania's 
responsive SIP revision, EPA may not consider unit-specific 
characteristics that the OTC did not identify in the recommendation as 
being potentially relevant?
     Is EPA's authority under section 184(c) to modify the 
OTC's recommendation limited such that EPA may not establish parameters 
for Pennsylvania regarding whether specific elements of a responsive 
SIP revision would (or would not) be consistent with the OTC's 
recommendation? As one hypothetical example, if EPA approves the OTC's 
recommendation, would it be permissible under CAA section 184(c) for 
EPA to identify a presumption that an approvable SIP would require 
compliance to be demonstrated on a unit-specific basis rather than 
through multi-unit averaging, even though the recommendation does not 
specifically state such a condition?

E. Materials Provided by the OTC To Support the Recommendation

    In addition to the recommendation itself (including the Delaware, 
Maryland, and New Jersey rules discussed in section III.C of this 
document), the OTC provided two other attachments of materials intended 
to support the recommendation. In this section, EPA summarizes these 
supporting materials and requests comment on them.
    The first supporting attachment to the OTC's recommendation is 
entitled ``Policy and Technical Rationale Supporting OTC's 
Recommendation for Additional Control Measures Under CAA Section 
184(c).'' The attachment includes background information, information 
intended to document the OTC's compliance with CAA section 184(c)'s 
procedural requirements, and a statement of the policy rationale 
summarized in section III.A of this

[[Page 4056]]

document. In addition, the attachment contains materials intended to 
serve as technical support for the recommendation, most of which were 
provided as part of Maryland's 2019 petition to the OTC:
     A table showing, for a subset of ozone monitoring 
locations across the OTR, preliminary 2017-2019 ozone design values, 
certified 2018 fourth highest ozone measurements, preliminary 2019 
fourth highest ozone measurements, and calculated threshold values for 
2020 fourth highest measurements that would result in 2018-2020 design 
values of 70 ppb or 75 ppb.
     A set of tables showing, for selected dates in the 2017 
and 2018 ozone seasons that correspond to ozone exceedances in 
Maryland, for various individual Pennsylvania coal-fired EGUs and the 
group of EGUs collectively, the amounts by which these units' reported 
NOX emissions exceeded Maryland's estimates of the emissions 
that would have occurred if the units' daily emission rates had equaled 
30-day rolling average emission rates or ozone-season average emission 
rates achieved by the same units during past ozone seasons in which 
those units reported their lowest average emission rates (attachment 3 
to Maryland's petition).
     A set of tables and charts showing, for selected ozone 
monitoring locations across the OTR and for each OTR state on average, 
differences in modeled ozone values between a case where Pennsylvania 
coal-fired EGUs' emissions were projected to reflect NOX 
control performance targets identified by Maryland versus a case where 
the units' emissions were projected to reflect Maryland's estimates of 
the units' allowable emissions without additional control measures 
(attachment 4 to Maryland's petition).
     A table showing, for individual Pennsylvania coal-fired 
EGUs, the 24-hour block average emission rates and 30-day rolling 
average emission rates that Maryland proposed as an ``Initial Straw-Man 
Draft'' of required control measures to be included in an OTC 
recommendation (attachment 5 to Maryland's petition).
     A document describing the methodology Maryland followed to 
develop the tables and charts provided as attachments 3 through 5 to 
its petition (attachment 6 to Maryland's petition).
    The second supporting attachment to the OTC's recommendation is a 
summary of the OTC's responses to comments that it received in its 
proceeding to develop the recommendation. One of the responses is a 
separate document entitled ``2017 OTR Ozone Season Exceedances of 2017 
NAAQS.'' \12\ This separate document describes an analysis of pollution 
back-trajectories that the OTC found shows potential connections 
between the locations of some Pennsylvania EGUs and the locations of 
some ozone exceedances in the OTR during 2017.
---------------------------------------------------------------------------

    \12\ Based on the document's content, it appears that the title 
contains a typographical error and was intended to reference the 
2015 ozone NAAQS.
---------------------------------------------------------------------------

    EPA requests comment on the information provided by the OTC to 
support its recommendation, particularly with respect to the question 
of whether the information does or does not support a determination by 
EPA that the control measures included in the recommendation are 
necessary to bring areas of the OTR into attainment with the 2008 and 
2015 ozone NAAQS.

IV. Historical Emissions Data for Pennsylvania Coal-Fired EGUs 
Potentially Affected by the Recommendation

    To assist in evaluating the OTC's CAA section 184(c) 
recommendation, EPA has examined historical emissions data for coal-
fired EGUs in Pennsylvania as well as Delaware, Maryland, and New 
Jersey, focusing on the units that continue to operate, as listed in 
Tables III-1 through III-5 above. With respect to NOX mass 
emissions, the data in those tables show that the 18 listed coal-fired 
EGUs with SCR or SNCR controls in Pennsylvania emitted 8,866 tons of 
NOX during the 2019 ozone season, compared to a total of 
1,606 tons emitted by the 12 listed units in Delaware, Maryland, and 
New Jersey, all of which have SCR, SNCR, or comparable controls.\13\
---------------------------------------------------------------------------

    \13\ The data in Table III-2 show that Pennsylvania coal-fired 
units without SCR or SNCR controls emitted an additional 976 tons of 
NOX in the 2019 ozone season.
---------------------------------------------------------------------------

    With respect to NOX emission rates, EPA has focused on 
comparing SCR-equipped units because the SCR-equipped units are 
generally larger than the SNCR-equipped units and have historically 
produced greater amounts of both electricity and NOX 
emissions. Table IV-1 shows the weighted average NOX 
emission rates for the 2015-2019 ozone seasons for all SCR-equipped 
coal-fired EGUs that continue to operate in each of the four states. 
The data indicate that the weighted average emission rates for the 
Pennsylvania SCR-equipped units were considerably higher than the 
weighted average rates for the other three states in 2015 and 2016, 
then declined sharply in 2017. In that year, a more stringent emissions 
budget for the units in Pennsylvania (as well as Maryland and New 
Jersey) was implemented under the CSAPR Update, and Pennsylvania units 
also became subject to more stringent RACT requirements.\14\ In 2017 
and 2018, the average emission rates for the Pennsylvania units were 
below the average rate for the New Jersey units but above the average 
rates for the Delaware and Maryland units. The average emission rate 
for the Pennsylvania units increased above the average rate for the New 
Jersey units in 2019 but remained well below 2015-2016 levels.
---------------------------------------------------------------------------

    \14\ The CSAPR Update and Pennsylvania RACT rules are discussed 
in sections V.A. and V.B. of this document.

     Table IV-1--Weighted Average Ozone Season NOX Emission Rates at Operating SCR-Equipped Coal-Fired EGUs
                                               [lb/mmBtu] [dagger]
----------------------------------------------------------------------------------------------------------------
                                                   Pennsylvania                                     New Jersey
                      Year                             units      Delaware units  Maryland units       units
----------------------------------------------------------------------------------------------------------------
2015............................................           0.252           0.094           0.059           0.117
2016............................................           0.233           0.078           0.058           0.111
2017............................................           0.099           0.084           0.057           0.112
2018............................................           0.102           0.086           0.064           0.112
2019............................................           0.130           0.082           0.060           0.108
----------------------------------------------------------------------------------------------------------------
[dagger] Includes only SCR-equipped units listed in Table III-1 and Tables III-3 through III-5. Each weighted
  average emission rate is computed as the sum of ozone season NOX emissions for the group of units divided by
  the sum of ozone season heat input for the group of units. Data are from EPA Clean Air Markets, Power Sector
  Emissions Data, Air Markets Program Data (AMPD).


[[Page 4057]]

    EPA has also examined the historical emissions data for individual 
coal-fired units in the four states. In recent years, many coal-fired 
units have experienced reduced overall utilization and more frequent 
cycling between lower and higher levels of output. In theory, more 
frequent cycling can cause a unit's average emission rate to increase 
because SCR controls may be less effective at lower load levels with 
correspondingly lower operating temperatures. To account for the 
possible impacts of changing operating patterns on NOX 
emission rates, for this unit-specific analysis EPA has grouped the 
hourly emission rate data for each unit according to the unit's heat 
input for the hour (using hourly heat input as a proxy for both hourly 
operating level and hourly operating temperature).\15\ The unit-
specific analyses for all the units are compiled into a technical 
support document entitled ``Analysis of Ozone Season NOX 
Emissions Data for Coal-fired EGUs in Four Mid-Atlantic States'' 
(referred to here as the ``Emissions Data TSD'') available in the 
docket for this action.
---------------------------------------------------------------------------

    \15\ EPA grouped the hourly data for each unit into ten evenly 
spaced ``bins'' based on the relationship of the unit's heat input 
in that hour to the unit's maximum hourly heat input capacity. Thus, 
bin 1 includes hours when the unit combusted between 0% and 10% of 
its maximum hourly heat input capacity and bin 10 includes hours 
when the unit combusted between 90% and 100% of its maximum hourly 
heat input capacity.
---------------------------------------------------------------------------

    For each unit, the Emissions Data TSD includes charts with data for 
the ozone seasons in the 2009-2019 period during which the unit 
achieved its lowest and third-lowest average NOX emission 
rates.\16\ In addition, data are also shown for the 2019 ozone season 
if that was not the year of the lowest or third-lowest average 
NOX emission rate. To indicate how operating patterns may 
have changed over time, an initial chart for each unit shows, for the 
set of selected ozone seasons, the number of hours during each of the 
ozone seasons in which the unit operated at each of the operating 
levels described above. Additional individual charts for each of the 
selected ozone seasons then display the unit's emission rate data and 
mass emissions data at each of the operating levels. The mass emissions 
data are displayed as bar charts, with each bar indicating the total 
NOX emitted during the selected ozone season in hours when 
the unit operated at that operating level. The hourly emission rate 
data values for each operating level are displayed by means of a ``box 
plot'' or ``box-and-whisker plot.'' Each ``box'' represents the middle 
half of all the hourly data values--that is, the hourly data values 
that fall in the ``interquartile range'' between the 25th percentile 
and 75th percentile hourly data values. The horizontal line in the box 
represents the median hourly data value. Vertical lines, or 
``whiskers,'' extend to the highest and lowest hourly data values that 
fall above or below the top or bottom edges of the box within a 
distance of up to 1.5 times the interquartile range. Any outlying 
hourly data values that fall above or below the top or bottom edges of 
the box by a distance of more than 1.5 times the interquartile range 
are shown as individual dots. Thus, a lower median data value and lower 
overall placement of the box on the chart indicate generally lower 
hourly emission rates, while shorter vertical distances between the top 
and bottom edges of the box and between the top and bottom ends of the 
whiskers, as well as fewer outliers, indicate lower variability (or 
greater consistency) of a unit's hourly emission rates at a given 
operating level. In this way, each box plot provides visual 
representations of both the magnitude and variability of a unit's 
hourly NOX emission rates at a given operating level in a 
single chart. For comparison purposes, each box plot also includes a 
horizontal dashed line showing the 0.12 lb/mmBtu emission rate limit 
that Pennsylvania's SCR-equipped units are required to meet--under 
certain operating conditions, on a 30-day rolling average basis--by the 
state's current RACT rules.\17\
---------------------------------------------------------------------------

    \16\ Data for the ozone season with each unit's third-lowest 
emission rate during the 2009-2019 period are included for 
comparability with the data sets EPA has used to identify emission 
reduction opportunities in the CSAPR Update and the proposed Revised 
CSAPR Update. Data for the ozone season with each unit's lowest 
emission rate during the same period are also included for greater 
comparability with the data provided by the OTC to support its CAA 
section 184(c) recommendation. EPA notes that for some units the OTC 
has provided data for ozone seasons before 2009.
    \17\ Pennsylvania's current RACT rules are summarized in section 
V.B. of this document.
---------------------------------------------------------------------------

    As examples of the more comprehensive analysis included in the 
Emissions Data TSD, the figures below show results for three SCR-
equipped units: Keystone unit 1 and Conemaugh unit 2, the two 
Pennsylvania units with the highest overall NOX mass 
emissions in the 2019 ozone season, and Brandon Shores unit 2, a 
Maryland unit that produced the largest amount of NOX 
emissions during the 2019 ozone season of any coal-fired EGU in 
Delaware, Maryland, or New Jersey.\18\
---------------------------------------------------------------------------

    \18\ The Keystone, Conemaugh, and Brandon Shores plants each 
have two coal-fired EGUs, and in each case EPA's data analysis for 
the plant's other unit resulted in charts similar to the charts for 
the plant's unit shown here. The charts for all the units are 
included in the Emissions Data TSD available in the docket.
---------------------------------------------------------------------------

    Figures IV-1 and IV-2 show data for Brandon Shores unit 2 for 2017 
(third-lowest average rate for 2009-2019) and 2019 (lowest average 
rate). Although the chart of operating hours indicates that in 2019 the 
unit spent more hours at operating levels 4-5 and fewer hours at 
operating levels 6-9 than in 2017, the distributions of the hourly 
emission rate data for 2017 and 2019 are still quite similar. In both 
years, hourly emission rate data for operating levels 4-10 are quite 
consistent, with half of the hourly data captured in thin boxes at 
emission rates below 0.10 lb/mmBtu. The hourly emission rate data for 
operating levels 1-3, generally representing start-up or shut-down 
conditions as indicated by the small numbers of operating hours, are 
less consistent and higher (at operating levels 2-3), indicating that 
the unit's SCR controls may not have operated until the unit reached 
operating level 4. The main difference between the emission rate data 
in the 2017 and 2019 box plots is a decrease in the number of outlier 
hours at operating level 6. Relative to 2017, mass emissions in 2019 
increased slightly at operating levels 4-5 and decreased by larger 
amounts at operating levels 6-9, with both the increases and decreases 
driven primarily by changes in the numbers of hours spent at the 
respective operating levels.
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    Figures IV-3 and IV-4 show data for Keystone unit 1 for 2010 
(lowest average rate for 2009-2019), 2017 (third-lowest average rate), 
and 2019. The data for 2010 show that almost all hours were spent at 
operating levels 6-8, and that hourly emission rates at load levels 6-9 
were very consistent, with half of the hourly data captured in thin 
boxes at emission rates below 0.10 lb/mmBtu. In 2017, there was a shift 
of hours from operating level 8 to operating level 7, emission rates 
continued to show consistency with thin boxes at operating levels 7-9 
but showed much greater variability at operating level 6, and the level 
of the boxes was higher than in 2010. In 2019, hours were spread more 
broadly, down to operating level 4 and a few hours at operating level 
10, and emission rates showed less consistency at operating level 7 
than in either 2010 or 2017.\19\ Relative to 2010 and 2017, the changes 
to mass emissions in 2019 include, first, an increase in emissions at 
operating level 8 that appears to be driven primarily by generally 
higher hourly emission rates at this operating level, and second, an 
increase in emissions at operating level 5 that appears to be driven 
primarily by an increase in hours spent at this operating level.
---------------------------------------------------------------------------

    \19\ EPA notes that additional analysis showed that the outlier 
values in the Keystone unit 1 hourly emission rate data at operating 
level 8 were spread across the ozone season and were not 
concentrated in a manner that would suggest controls were being 
intentionally idled on particular days. See Emissions Data TSD at 
Section 3.2.
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    Figures IV-5 and IV-6 show data for Conemaugh unit 2 for 2016 
(third-lowest average rate for 2009-2019), 2018 (lowest average rate), 
and 2019. The data for 2016 show that hours were spread across 
operating levels 4-9, and only operating levels 8-9 showed somewhat 
thin boxes indicating relatively consistent hourly emission rates. In 
2018, hours were spread across operating levels 5-9, with a heavy 
concentration at operating level 9, and the unit's emission rate data 
showed consistently thin boxes across all of those load levels at 
emission rates below 0.10 lb/mmBtu, although with outliers at most 
operating levels. In 2019, hours were again spread across operating 
levels 5-9, with an increase at operating level 5, and consistent 
emission rates with a thin box were achieved only at operating level 9, 
with a relatively high frequency of outlier values.\20\ Relative to 
2016 and 2018, the changes to mass emissions in 2019 include, first, 
increases in emissions at operating level 6-8 that appear to be driven 
primarily by generally higher hourly emission rates at these operating 
levels, and second, a large increase in emissions at operating level 5 
that appears to be driven primarily by generally higher hourly emission 
rates at this operating level but also to some extent by an increase in 
hours spent at this operating level.
---------------------------------------------------------------------------

    \20\ EPA notes that additional analysis showed that the outlier 
values in the Conemaugh unit 2 hourly emission rate data at 
operating level 9 were spread across the ozone season and were not 
concentrated in a manner that would suggest controls were being 
intentionally idled on particular days. See Emissions Data TSD at 
Section 3.2.
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BILLING CODE 6560-50-C
    EPA requests comment on the analysis of emissions and operating 
data contained in the Emissions Data TSD and summarized in this 
section, including but not limited to the following questions:
     To what extent do the data support a conclusion that that 
coal-fired EGUs in Pennsylvania equipped with SCR or SNCR controls 
could further optimize operation of those controls to reduce 
NOX emissions during the ozone season, notwithstanding 
changes in the units' operating patterns in recent years?
     To what extent do the data support a conclusion that any 
particular type of control measure--i.e., a requirement to operate and 
optimize controls, a daily NOX emission rate limit, or some 
combination of the two--would be more or less effective at reducing 
ozone season NOX emissions from the Pennsylvania units?

V. Current Regulatory Context

    The OTC's CAA section 184(c) recommendation is made in the context 
of ongoing activities addressing other CAA provisions. At least two 
such activities appear to have the potential to cause reductions in 
emissions from the Pennsylvania EGUs potentially affected by the OTC's 
recommendation by the point in time at which emissions reductions could 
be anticipated in response to an approval or partial approval of the 
OTC's recommendation, and the resulting SIP call and implementation. 
The first is EPA's Revised CSAPR Update rulemaking to address the 
interstate pollution transport obligations of states including 
Pennsylvania with respect to the 2008 ozone NAAQS, 85 FR 68964 (October 
30, 2020). The second is Pennsylvania's proceedings to revise 
NOX RACT requirements applicable to the state's coal-fired 
EGUs. In this section, EPA discusses these activities and requests 
comment on the relevance of these or other activities to EPA's decision 
on whether to approve, disapprove, or partially approve and partially 
disapprove the OTC's recommendation.

A. Revised CSAPR Update

    Starting more than two decades ago, EPA has issued multiple rules 
requiring reductions in NOX emissions to address the 
interstate transport of NOX as an ozone precursor, including 
the NOX SIP Call, 63 FR 57356 (October 27, 1998); the Clean 
Air Interstate Rule (CAIR), 70 FR 25162 (May 12, 2005); the Cross-State 
Air Pollution Rule (CSAPR), 76 FR 48208 (August 8, 2011); and the CSAPR 
Update, 81 FR 74504 (October 26, 2016).\21\ These actions were all 
taken under the authority of CAA section 110(a)(2)(D)(i)(I), often 
referred to as the ``good neighbor provision.'' The rules were 
implemented through enforceable emission limits (emission budgets) that 
were designed to incentivize emission reductions while providing 
sources with flexibility as to the specific control strategies 
employed. Depending on the rule, the budgets were set at stringencies 
reflecting control measures that include new combustion or post-
combustion controls, operation of existing post-combustion controls, 
and shifting of generation to lower emitting units.
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    \21\ EPA's CSAPR Close-Out, 83 FR 65878 (Dec. 21, 2018), 
determined that no further NOX reductions were required 
in upwind states to address downwind nonattainment and maintenance 
problems for the 2008 ozone NAAQS based on EPA's assessment of the 
analytical year 2023.
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    The CSAPR Update addressed ozone transport under the 2008 ozone 
NAAQS by establishing more stringent statewide

[[Page 4064]]

budgets for ozone season NOX emissions from EGUs in 22 
states starting in 2017. The covered states include Pennsylvania, 
Maryland, and New Jersey. In Wisconsin v. EPA, 938 F.3d 303 (D.C. Cir 
2019), the D.C. Circuit court upheld the CSAPR Update in most respects 
but remanded the rule to EPA for failing to fully address good neighbor 
obligations of the affected states with respect to the 2008 ozone NAAQS 
by the applicable attainment dates.\22\ On October 30, 2020, EPA 
published a proposal for a Revised CSAPR Update in response to the 
court's remand that, based on new analysis, would establish reduced 
NOX ozone season emission budgets for 12 states including 
Pennsylvania. 85 FR 68964. Under EPA's proposal, if finalized, this 
rule would fully resolve the outstanding good neighbor obligations for 
Pennsylvania and the other eleven states for the 2008 ozone NAAQS. The 
rule does not, however, address the 2015 ozone NAAQS. As under the 
CSAPR Update, the proposed budgets are based on emission reductions 
achievable through full operation of existing SCR controls, upgrade of 
combustion controls where possible, and limited generation shifting.
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    \22\ The D.C. Circuit vacated the CSAPR Close-Out determination 
in New York v. EPA, 781 Fed. App'x 4 (D.C. Cir. 2019), for the same 
flaw it found in the CSAPR Update in Wisconsin.
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    To develop the proposed emission budgets for the Revised CSAPR 
Update, EPA identified SCR-equipped units in the relevant upwind states 
whose 2019 emission rate data suggested they were not optimizing their 
SCR controls to achieve an average emission rate of 0.08 lb/mmBtu or 
less during the ozone season.\23\ EPA then projected the emission 
reductions that would be achieved if each of these units reduced its 
average emission rate to 0.08 lb/mmBtu, while units already achieving 
lower emission rates continued to do so. This methodology resulted in 
projected emission reductions from Pennsylvania units (implemented 
through an ozone season cap) of over 3,100 tons through SCR 
optimization alone. The proposed 2021 budget for Pennsylvania is 33% 
lower than the state's 2019 ozone season emission levels. EPA has a 
court-ordered deadline to take final action on the Revised CSAPR Update 
by March 15, 2021.\24\
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    \23\ For both the CSAPR Update and the proposed Revised CSAPR 
Update, EPA based its assessment of the emission reductions 
achievable through operation and optimization of SCR controls on the 
average of the third-lowest ozone season average emission rates 
achieved by SCR-equipped units nationwide. For the CSAPR Update, EPA 
considered data for the period from 2009 through 2015 and the 
resulting average emission rate was 0.10 lb/mmBtu. For the proposed 
revised CSAPR Update, EPA considered data for the period from 2009 
through 2019 and the resulting average emission rate was 0.08 lb/
mmBtu. See 85 FR at 68990-91.
    \24\ See New Jersey v. EPA, No. 1:20-cv-01425 (S.D.N.Y. July 28, 
2020).
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    In focusing on emission reductions achievable through optimization 
of existing SCR controls, the Revised CSAPR Update bases its emission 
budgets for Pennsylvania to a considerable extent on the same units 
from which emission reductions are sought under the OTC's section 
184(c) recommendation. The two regulatory initiatives would employ 
different compliance mechanisms, with the OTC's recommendation centered 
on unit-specific daily limits while the Revised CSAPR Update would 
employ a flexible trading program implemented through regionwide 
emission caps, and state emission budgets and assurance levels. The 
Revised CSAPR Update's budgets would reflect a much more stringent 
target emission rate of 0.08 lb/mmBtu (on an ozone season average 
basis) than the 0.125 lb/mmBtu and 1.5 lb/MWh rates (on a daily basis) 
in the Delaware and New Jersey rules.\25\ EPA also notes that under the 
procedural requirements of section 184(c), it is likely that any 
emission reductions resulting from approval of the OTC's recommendation 
could not be anticipated until the 2022 ozone season, given that EPA's 
deadline for acting on the recommendation falls in March 2021 and would 
be followed by a SIP call process. In contrast, EPA has proposed to 
implement the Revised CSAPR Update starting in the 2021 ozone season.
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    \25\ As previously noted, for a typical range of heat rates for 
coal-fired units of 9,000 to 11,000 Btu/kWh, an emission rate limit 
of 1.5 lb/MWh would be equivalent to emission rate limits in a range 
of 0.136 to 0.167 lb/mmBtu.
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    In light of the substantial overlap in the Pennsylvania sources 
that would be affected by the Revised CSAPR Update and by the OTC's 
section 184(c) recommendation, and recognizing the differences in the 
proposed structure, stringency, and implementation timing of the two 
initiatives, EPA requests comment on whether and how the potential 
finalization and implementation of the Revised CSAPR Update bears on 
the question of whether the additional control measures sought in the 
OTC's section 184(c) recommendation are necessary to achieve attainment 
of the 2008 or 2015 ozone NAAQS in the OTR.

B. Pending Revisions to Pennsylvania NOX RACT Requirements

    Under CAA sections 184(b) and 182(f)(1), all states in the OTR must 
implement NOX RACT on a statewide basis for sources meeting 
certain criteria, generally including coal-fired EGUs. In addition, 
each OTR state generally must update its RACT determinations for each 
revised ozone NAAQS. See 40 CFR 51.1116 and 51.1316. Pennsylvania most 
recently updated its NOX RACT requirements for coal-fired 
EGUs in 2016 to address the 2008 ozone NAAQS (Pennsylvania calls these 
requirements ``RACT II''). The requirements, which first became 
effective in January 2017, are codified at 25 Pa. Code Sec. Sec.  
129.96-129.100: Additional RACT Requirements for Major Sources of 
NOX and VOC. Section 129.97 sets ``presumptive'' RACT 
requirements for certain categories of sources, including coal-fired 
combustion units with SCR controls (129.97(g)(1)(viii)) and coal-fired 
combustion units with SNCR controls (129.97(g)(1)(ix)). Section 
129.97(g)(1)(viii) requires that existing SCR-equipped coal-fired EGUs 
not exceed a NOX emission rate limit of 0.12 lb/mmBtu when 
operating with an SCR inlet temperature greater than or equal to 600 
degrees Fahrenheit. Section 129.97(g)(1)(ix) requires that coal-fired 
combustion units with SNCR controls must operate their SNCR controls 
when operating with a temperature in the reagent injection area greater 
than or equal to 1,600 degrees Fahrenheit but does not set a 
NOX limit. Section 129.97(g)(1)(vi) establishes additional 
NOX emission rate limits that apply to coal-fired combustion 
units with rated heat input capacities greater than 250 million Btu per 
hour but operating at lower temperatures without regard to their 
installed control equipment: 0.16 lb/mmBtu for fluidized bed units, 
0.35 lb/mmBtu for tangentially fired units, and 0.40 lb/mmBtu for all 
other types of units. Under section 129.100(a)(1), compliance with all 
of these limits must be demonstrated on a 30-day rolling average basis. 
Section 129.98 allows the emission rate limits to be met through 
averaging with other units subject to Pennsylvania's RACT requirements 
(including non-coal-fired units) under the control of the same owner or 
operator. EPA conditionally approved Pennsylvania's rules as satisfying 
NOX RACT requirements in a revision to Pennsylvania's SIP, 
but the limits in section 129.97(g)(1)(viii) and (ix) were fully 
approved. 84 FR 20274 (May 8, 2019). However, the U.S. Court of Appeals 
for the Third Circuit

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subsequently vacated and remanded the portion of EPA's approval 
concerning the 0.12 lb/mmBtu limit for coal-fired EGUs with SCR 
controls, and the 600 degree temperature exemption for that limit, both 
of which are found in section 129.97(g)(1)(viii). The court held that 
the approval of this specific provision was not supported by adequate 
facts or reasoning in the record. Sierra Club v. EPA, 972 F.3d 290, 
299-307 (3d Cir. 2020).\26\ EPA has not yet proposed any action in 
response to the remand, nor has Pennsylvania proposed or adopted 
updates to its RACT II rules.
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    \26\ The Court also found that the recordkeeping and reporting 
requirement in section 129.100(d)(1) was inadequate to ensure that 
the 0.12 lb/mmBtu limit was being met because it did not 
specifically require that the inlet temperature to the SCR be 
recorded and reported. Sierra Club v. EPA, 972 F.3d 290, 307-309 (3d 
Cir. 2020).
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    In 2019, Pennsylvania started the process of updating its RACT 
requirements for the 2015 ozone NAAQS (referred to as ``RACT III'') by 
discussing potential concepts for a rule at its Air Quality Technical 
Advisory Committee meetings. For EGUs, the draft rule would require 
SCR-equipped and SNCR-equipped units to optimize the use of their 
controls consistent with technological limitations, manufacturer 
specifications, good engineering and maintenance practices, and good 
air pollution control practices. The rule would continue to 
differentiate the applicable emission rate limits based on specified 
temperature thresholds and generally would not change the levels of the 
emission rate limits for SCR-equipped coal-fired EGUs established in 
the RACT II rule, but would require compliance to be demonstrated on a 
daily average basis instead of a 30-day rolling average basis. In 
addition, a new emission rate limit of 0.10 lb/mmBtu on a 30-day 
rolling average basis would be established for SCR-equipped coal-fired 
units when operating with an SCR inlet temperature greater than or 
equal to 600 degrees Fahrenheit. Compliance generally could still be 
demonstrated by averaging across units under the control of the same 
owner or operator. The new rules would generally be implemented by 
January 1, 2023.\27\ The OTC recognizes Pennsylvania's efforts to 
update its RACT requirements and has indicated its intention to 
withdraw the CAA section 184(c) recommendation if Pennsylvania adopts a 
rule addressing the recommendation. EPA notes that the draft RACT III 
rule described above was prepared before the court remand of EPA's 
approval of the state's RACT II rule.
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    \27\ See Pennsylvania Department of Environmental Protection, 
``Draft Proposed RACT III Rulemaking'' (Feb. 13, 2020) at 15-21, 
available in the docket for this action and at http://files.dep.state.pa.us/Air/AirQuality/AQPortalFiles/Advisory%20Committees/Air%20Quality%20Technical%20Advisory%20Committee/2020/2-13-20/RACT%20III%20Requirements%20AQTAC%20Presentation%202-13-2020.pdf.
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    EPA requests comment on whether and how Pennsylvania's RACT III 
rulemaking, as well as the remand of EPA's approval of Pennsylvania's 
RACT II SIP submittal, may bear on EPA's decision to approve, 
disapprove, or partially approve and partially disapprove the OTC's 
section 184(c) recommendation, including but not limited to the 
following questions:
     If EPA approved the OTC's section 184(c) recommendation 
and, in response to the resulting SIP call, Pennsylvania submitted a 
rule along the lines of the draft RACT III rule discussed above, could 
EPA approve the draft rule as meeting the OTC's recommendation? That 
is, could EPA determine that the draft rule is as stringent as the 
Delaware, Maryland, or New Jersey rules included in the OTC's 
recommendation? If the rule would not be approvable, how would 
Pennsylvania need to modify the draft rule to make it meet the OTC's 
recommendation?
     Is it appropriate for EPA to evaluate the necessity of 
additional measures for bringing areas in the OTR into attainment prior 
to the establishment of OTR RACT for VOC and NOX under CAA 
section 184(b) (and, for NOX, the extension provision of CAA 
section 182(f)(1))? Given that section 184(c) and section 184(b) 
establish independent requirements, is it appropriate for EPA to 
conclude that a specific set of recommended additional measures may be 
necessary under section 184(c) and mandate their implementation without 
having first given Pennsylvania an opportunity to adopt a potentially 
different set of measures as RACT for purposes of the 2015 ozone NAAQS 
that could render some or all of the recommended additional measures 
unnecessary as related to that NAAQS?

C. Other Pending Regulatory Activities

    In addition to the proposed Revised CSAPR Update and Pennsylvania's 
efforts to update RACT requirements, it is possible that activities 
being undertaken to meet other CAA requirements could result in 
requirements for coal-fired EGUs in Pennsylvania to reduce 
NOX emissions. For example, promulgation of the 2015 ozone 
NAAQS triggered a requirement, which has not yet been met, for 
Pennsylvania to revise its SIP to address the state's obligations under 
the good neighbor provision for this NAAQS.\28\ Also, on March 12, 
2018, New York submitted a petition to EPA under CAA section 126(b) 
seeking a finding that approximately 350 sources in nine states, 
including all of the Pennsylvania EGU facilities potentially affected 
under the OTC's section 184(c) recommendation, emit or would emit 
NOX in violation of the good neighbor provision with respect 
to the 2008 and 2015 ozone NAAQS. Although EPA denied that petition, 84 
FR 56058 (Oct. 18, 2019), the D.C. Circuit subsequently vacated the 
denial and remanded for EPA to promulgate a revised response, New York 
v. EPA, 964 F.3d 1214, 1226 (D.C. Cir. 2020).
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    \28\ On December 5, 2019, EPA published findings that 
Pennsylvania and several other states had failed to submit SIP 
revisions to address their good neighbor obligations with respect to 
the 2015 ozone NAAQS. 84 FR 66612.
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    EPA requests comment on whether and how regulatory activities 
besides the proposed Revised CSAPR Update and Pennsylvania's efforts to 
update RACT requirements, including but not limited to activities 
addressing the requirements noted above, may bear on EPA's decision to 
approve, disapprove, or partially approve and partially disapprove the 
OTC's section 184(c) recommendation.

    Dated: December 15, 2020.
Anne L. Austin,
Principal Deputy Assistant Administrator.

Appendix: OTC Recommendation

OTC Recommendation for Establishing Daily Limits for Coal-Fired EGUs in 
Pennsylvania To Ensure That Existing Control Technologies are Optimized 
To Minimize Nitrogen Oxide Emissions Each Day of the Summer Ozone 
Season

    The Ozone Transport Commission (OTC) recommends that the U.S. 
EPA require Pennsylvania to revise the Pennsylvania State 
Implementation Plan to include additional control measures which 
would establish daily nitrogen oxides (NOX) emission 
limits for all coal-fired EGUs with already installed Selective 
Catalytic Reduction (SCR) or Selective Non Catalytic Reduction 
(SNCR) control technology to ensure that these technologies are 
optimized to minimize NOX emissions each day of the ozone 
season.
    These requirements must be as stringent as any one of the rules 
attached. These rules all establish daily limits designed to 
optimize the use of SCR and SNCR control technologies to minimize 
NOX emissions each day of the ozone season. Daily 
NOX limits for coal-fired EGUs have been adopted by 
Delaware, New Jersey and Maryland, three of the states adjacent to 
and directly downwind of Pennsylvania. Pennsylvania contributes 
significantly to four downwind nonattainment areas in the OTC 
including Washington DC, Baltimore, Philadelphia, and

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New York City. During the summer of 2018, NOX emissions 
from coal-fired EGUs in Pennsylvania equipped with SCR and SNCR were 
more than four times greater than the NOX emissions from 
coal-fired EGUs in Delaware, New Jersey and Maryland combined.
    Pennsylvania has not yet adopted daily NOX limits for 
coal-fired EGUs. Therefore, the OTC is recommending that EPA require 
Pennsylvania to adopt and implement daily NOX limits as 
expeditiously as practicable. It is our hope that the three options 
embodied in the Delaware, New Jersey and Maryland regulations will 
provide Pennsylvania with the flexibility to implement daily 
NOX limits in a time frame to help downwind OTC states 
attain the 2015 ozone standard by the dates required in the Clean 
Air Act.
    Because this recommendation does not involve the purchase or 
installation of new control technologies, the OTC urges EPA to 
require that Pennsylvania implement these requirements in time to 
reduce ozone levels during the summers of 2020 and 2021. All of the 
marginal nonattainment areas in the Ozone Transport Region (OTR) are 
on a path to not attain the 2015 ozone standard by 2021, the 
mandated attainment date for marginal nonattainment areas, if 
additional NOX reductions are not achieved.
    Attachments [not shown]:
1. Delaware Administrative Code, Title 7 Natural Resources & 
Environmental Control, 1100 Air Quality Management Section, 1146 
``Electric Generating Unit (EGU) Multi-Pollutant Regulation'' (pages 
1-9).
2. New Jersey State Department of Environmental Protection, New 
Jersey Administrative Code, Title 7, Chapter 27, Subchapter 19, 
``Control and Prohibition of Air Pollution from Oxides of Nitrogen'' 
(pages 1 & 27-29).
3. Maryland--Code of Maryland Regulations (COMAR), Title 26 
Department of the Environment, Subtitle 11 Air Quality, Chapter 38, 
``Control of NOX Emissions from Coal-Fired Electric 
Generating Units'' (pages 1-6).
[FR Doc. 2021-00864 Filed 1-14-21; 8:45 am]
BILLING CODE 6560-50-P