[Federal Register Volume 89, Number 84 (Tuesday, April 30, 2024)]
[Rules and Regulations]
[Pages 34137-34144]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-08713]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R01-OAR-2023-0188; FRL-11025-03-R1]
Air Plan Approval; New Hampshire; Reasonable Available Control
Technology for the 2008 and 2015 Ozone Standards
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Environmental Protection Agency (EPA) is approving State
Implementation Plan (SIP) revisions submitted by the State of New
Hampshire. The revisions establish NOX reasonably available
control technology (RACT) requirements for coal-fired cyclone boilers
located in the state, portions of New Hampshire's NOX RACT
certifications for the 2008 and 2015 ozone standards that pertain to
requirements for coal-fired cyclone boilers, and withdrawal from the
SIP of two previously issued RACT orders. This action is being taken in
accordance with the Clean Air Act (CAA).
DATES: This rule is effective on May 30, 2024.
ADDRESSES: EPA has established a docket for this action under Docket
Identification No. EPA-R01-OAR-2023-0188. All documents in the docket
are listed on the https://www.regulations.gov website. Although listed
in the index, some information is not publicly available, i.e., CBI or
other information whose disclosure is restricted by statute. Certain
other material, such as copyrighted material, is not placed on the
internet and will be publicly available only in hard copy form.
Publicly available docket materials are available at https://www.regulations.gov or at the U.S. Environmental Protection Agency, EPA
Region 1 Regional Office, Air and Radiation Division, 5 Post Office
Square--Suite 100, Boston, MA. EPA requests that if at all possible,
you contact the contact listed in the FOR FURTHER INFORMATION CONTACT
section to schedule your inspection. The Regional Office's official
hours of business are Monday through Friday, 8:30 a.m. to 4:30 p.m.,
excluding legal holidays and facility closures due to COVID-19.
FOR FURTHER INFORMATION CONTACT: Bob McConnell, Environmental Engineer,
Air and Radiation Division (Mail Code 5-MD), U.S. Environmental
Protection Agency, Region 1, 5 Post Office Square, Suite 100, Boston,
Massachusetts, 02109-3912; (617) 918-1046; [email protected].
SUPPLEMENTARY INFORMATION:
Throughout this document whenever ``we,'' ``us,'' or ``our'' is
used, we mean EPA.
Table of Contents
I. Background and Purpose
II. Response to Comments
III. Final Action
IV. Incorporation by Reference
V. Statutory and Executive Order Reviews
I. Background and Purpose
On July 10, 2023 (88 FR 43483), EPA published a Notice of Proposed
Rulemaking (NPRM) for the State of New Hampshire. The NPRM proposed to
determine that the State has adopted regulations meeting the
requirements for reasonably available control technology (RACT) for the
2008 and 2015 ozone national ambient air quality standards (NAAQS), to
approve amendments to a related regulation that New Hampshire revised
as part of its RACT certifications for these two NAAQS, to approve a
revision to the State's definition of emergency generator, and removal
from the SIP of two previously issued RACT orders affecting coal-fired
cyclone boilers operated by Merrimack Station located in Bow, New
Hampshire. EPA received a comment letter from the Sierra Club dated
August 9, 2023, that opposed New Hampshire's NOX RACT limits
applicable to coal-fired cyclone boilers. We approved the portions of
the proposal unaffected by this comment letter in a final rule
published on September 6, 2023 (88 FR 60893). In this final rule, we
are approving the remaining portions of these SIP revisions, which
include requirements within New Hampshire's Env-A 1300 establishing
RACT requirements for coal-fired electrical cyclone boilers, the
portions of New Hampshire's NOX RACT certifications for the
2008 and 2015 ozone standards that pertain to requirements for coal-
fired cyclone boilers, and we are taking final action to withdraw from
the New Hampshire SIP two RACT orders that contain less stringent
requirements for cyclone boilers. Please see our July 10, 2023 proposed
rule for additional background
[[Page 34138]]
and a more detailed explanation of our proposed action.
II. Response to Comments
As mentioned, we received one comment letter on our July 10, 2023
proposed approval, which was from the Sierra Club and expressed
opposition to the proposed approval of New Hampshire's (NH's)
NOX RACT requirements applicable to the coal-fired cyclone
boilers operated by Granite Shore Power at its Merrimack Station
electrical generating facility located in Bow. Our responses to the
comments raised by Sierra Club appear below.
Comment: Sierra Club commented that the emission rate of 0.22 lbs/
MMBtu for two coal-fired cyclone boilers at Merrimack Station, herein
referred to as units MK1 and MK2, is inadequate as RACT. Sierra Club
commented that, since 2018, MK1 and MK2 consistently demonstrated the
ability to meet a 24-hour average emission rate at or below 0.20 lbs/
MMBtu, which is 10% lower than NH's emissions limit of 0.22 lbs/MMBtu,
and thereby asserted that the state's limit is too lenient.
Response: New Hampshire developed its NOX RACT emissions
limits for MK1 and MK2 in consideration of a number of factors. One
such factor was the observation that the selected emissions limit of
0.22 lbs NOX/MMBtu represented emission reductions of 83%
and 91% from uncontrolled levels for MK1 and MK2, respectively,\1\
which is a high level of control. Given MK2's larger size and
emissions, the emissions weighted average reduction from uncontrolled
levels for both units combined is 88% based on emissions data for 2022.
This level of control is near the upper end of the emission reduction
capability of selective catalytic reduction (SCR) control systems as
noted within EPA control technology explanatory materials, such as the
agency's fact sheet on SCR NOX control technology, which
indicates a control range of between 70-90% is achievable from such
systems.\2\ Additionally, correspondence dated May 25, 2018 from the
facility owner, Granite Shore Power, to the New Hampshire DES indicated
that a more restrictive normal operating mode emission rate of 0.20
lbs/MMBtu on a 24-hr basis that was originally considered by NH DES was
beyond the original emission reduction control capability of the units
when they were newly installed. Granite Shore Power reiterated this
point in a January 17, 2020 correspondence to the New Hampshire DES
concerning regional haze requirements in which they note that the
revised NOX RACT limits ``represent the most effective use
of the SCR, given that the system must be operated year round at or
above its design capacity to demonstrate compliance.''
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\1\ NH based its emission reduction calculations on the
uncontrolled levels observed during stack tests for MK1 and MK2.
\2\ Air Pollution Control Technology Fact Sheet: Selective
Catalytic Reduction (SCR); EPA-452/F-03-032.
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In 2018 as New Hampshire was developing its NOX RACT
emissions limit for MK1 and MK2, the state reviewed the emissions data
from the continuous emissions monitoring systems (CEMS) on the units
collected in 2000, when the equipment was newly installed, through
2007. Merrimack Station installed a second SCR control unit in 1999 due
to the Ozone Transport Region (OTC) NOX budget program.
Previously only one of the Merrimack Station units had SCR, installed
circa 1995. This period of time coincides with the period of time that
Electric Generating Units (EGUs) in New Hampshire had new emission
control obligations under the OTC's NOX Budget program.\3\
This program began in 1999 and continued through 2002, at which point
most of the EGUs transitioned to the EPA's first ozone season
NOX control program, that being the NOX SIP
Call.\4\ Although EGUs in New Hampshire were not required to
participate in the EPA's NOX SIP Call program, New Hampshire
maintained, as an anti-backsliding measure, the OTC NOX
Budget program's ozone season cap for sources located in the state,
including MK1 and MK2, beyond 2002. EPA facilitated oversight of New
Hampshire's post-2002 NOX Budget program by creating a
separate account referred to as the ``NH NOX Program'' on
its Clean Air Markets Program Data (CAMPD) website.\5\
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\3\ EPA approved the program New Hampshire developed to comply
with the OTC's NOX Budget program into the NH SIP on
November 14, 2000 (see 65 FR 68078).
\4\ See EPA's October 27, 1998, (63 FR 57356) final rulemaking
action known as the NOX SIP Call.
\5\ The NOX emissions data for the New Hampshire's
EGU's, including MK1 and MK2, are still maintained on the CAMPD
website by retrieving data under the program name ``NH
NOX Program''.
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New Hampshire's selection of 0.22 lbs NOX/MMBtu, to be
met on a 24-hour averaging time basis, is reasonable from a statistical
perspective. The emissions limit New Hampshire chose corresponds to the
emissions rate representative of the 95th percentile emissions rate for
days of operation without a startup or shutdown event. In other words,
MK1 and MK2 operated at or below an emission rate of 0.22 lbs
NOX/MMBtu 95 percent of the time between 2000 and 2007,
which as mentioned above coincided with the time period when the SCR
controls were newly installed and MK1 and MK2 were subject to the
requirements of the OTC's NOX budget program that began in
1999.
The data Sierra Club show in Table 2 of their comment letter are
based on monthly averages, whereas the limits being approved herein for
Merrimack Station are short term, 24-hour averages. Shorter term limits
are harder to meet and require that the control system be consistently
and effectively run. Conversely, a 30-day average can be met despite
days on which the controls are not run effectively, or perhaps not run
at all, as long as there are enough days of operation below the
emission limit to average this out. If the short-term emissions limit
NH requires for MK1 and MK2 were set at a lower rate, such as 0.20 or
below as Sierra Club suggests, there would be many days with violations
due to minor fluctuations in the rate of the chemical reaction that
occurs between the catalyst system, ammonia, and oxygen, which
accomplishes the reduction in NOX emissions in the effluent
from the equipment. NH reviewed historic data and identified periods of
time when the facility's controls produced low daily emissions rates.
Importantly, during those past time periods, the facility was not
required to meet a 24-hour emissions rate. By imposing a new, 24-hour
emissions limit, NH had to choose an emissions rate that was feasible,
given the normal fluctuations in the boiler and control system
operations, that the facility could reasonably be expected to meet
every day. Although historic data showed the facility could meet a 0.22
rate 95% of the time, that also means that it did not meet that rate 5%
of the time. It now will be required to meet that rate 100% of the
time. A description of how SCR control systems operate and the various
aspects of the induced chemical reaction that occurs to change the
nitrogen oxides released from the combustion process to elemental
nitrogen and water vapor is contained within the SCR Air Pollution
Control Fact Sheet included in the docket for this final rule.
New Hampshire also considered limits adopted by other states for
similar equipment in making its NOX RACT determination, but
could not find reasonable comparisons based on coal type, boiler design
type, boiler age, and control technology. This point is discussed in
further detail below. Lastly, we note that the SCR control systems
operated by Merrimack Station
[[Page 34139]]
were amongst the first such units installed on coal-fired electric
utility boilers in the U.S., with MK2's SCR being installed in 1995,
and MK1's in 1999. Despite the age of the control equipment, the
overall NOX control efficiency as noted above remains at a
high level. Additionally, as explained further in the TSD accompanying
this final action, by observing the hourly emissions rate data
available from EPA's Clean Air Markets Program Database (CAMPD) website
it can be clearly seen that achievement of this rate on a 24-hour
averaging time basis requires the continuous operation of the SCR
controls, as even one or two hours of operation without the controls
engaged while heat input is high would jeopardize achievement of the
short term, 0.22 lbs/MMBtu emission limit.
Comment: Sierra Club commented that other coal-fired cyclone
boilers are required to meet lower emissions limits and included data
for other cyclone boilers to support its claim. Sierra Club also
provided data on NOX emission rates at Merrimack Station and
asserted that lower NOX emission rates are achievable and
should be required by RACT.
Response: EPA agrees that there are other coal-fired cyclone
boilers that are required to meet lower emissions limits. However,
EPA's review of the characteristics of the coal-fired cyclone boilers
identified as such within its Clean Air Markets and National Electric
Energy Data System (NEEDS) databases and operating since 2009 indicates
that only two units, the now closed Dallman units 31 and 32 in
Illinois, have technical specifications similar to the Merrimack units
in that they were bituminous coal fired cyclone boilers whose
NOX emissions were controlled solely by SCR. However, those
units are not directly comparable to MK1 and MK2 for a number of
reasons, including their smaller size, newer age of the SCR control
equipment, and for comparison to MK2, that unit's inordinately high
uncontrolled emission rate of 2.4 lbs. NOX/MMBtu, which is
considerably higher than the average emission rate for bituminous coal-
fired cyclone boilers of 1.3 lbs/MMBtu as documented within Table 1.1-3
of section 1.1 of EPA's emissions factors reference document, AP-42.
Although we did identify several other bituminous coal-fired cyclone
boilers within EPA databases, those boilers operated additional
NOX control equipment not used by MK1 and MK2, most often
overfire air (OFA) systems. The boilers located at the New Madrid and
Thomas Hill facilities in Missouri noted by Sierra Club also operate
OFA systems in addition to the SCR control system. Granite Shore Power
(GSP), Merrimack Station's owner, recently evaluated the feasibility of
retrofitting its cyclone boilers with additional NOX
emission control equipment including an overfire air system as part of
a technical analysis it performed at the request of the New Hampshire
Air Resources Division (NH-ARD). The state made this request as it
developed its SIP revision for the Regional Haze program. As New
Hampshire notes within its May 5, 2022, Regional Haze Plan, GSP
concludes that retrofitting MK1 and MK2 was not feasible for the
following reason:
``OFA would result in reduced boiler performance, potential boiler
modifications to boiler surface areas, increased fouling, boiler tube
erosion, and cyclone wear. Any installation is complicated by, if not
impossible, due to the engineering and design challenges of the windbox
configuration and screen tubes at Merrimack. In addition, the
installation of an OFA system after the installation of an SCR is
likely to produce little to no improvement in NOX
reductions. Any of these changes would also have the potential to
negatively impact the removal capability of the FGD (flue gas
desulfurization) \6\ and the collection capability of the ESPs
(electrostatic precipitators \7\).'' As documented within section 4.2.9
of its May 5, 2022, Regional Haze Plan Periodic Comprehensive Revision,
New Hampshire reviewed and agreed with Granite Shore Power's assessment
that NOX emissions from the coal-fired boilers at Merrimack
Station are well controlled and subject to appropriate NOX
emissions limits. Large boilers like these vary considerably in their
design and operational characteristics, and so retrofits possible for
some equipment may not be possible elsewhere.
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\6\ FGD systems are used to reduce emissions of sulfur dioxide
and mercury.
\7\ ESP systems are used to reduce emissions of particulate
matter.
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EPA has reviewed New Hampshire's assessment of the information
provided by GSP and agrees with the state's conclusion that requiring
installation of new equipment at the Merrimack units, such as OFA, is
not economically feasible for purposes of RACT. The facility is
scheduled to permanently cease coal-fired boiler operations no later
than June 1, 2028 as indicated by a recent agreement between Granite
Shore Power, the EPA, the Sierra Club, and the Conservation Law
Foundation.\8\ Leading up to this cessation in operations, there is a
declining need for output from the facility by the region's electrical
grid operator, ISO-New England; there has been limited or non-
acceptance of offers to produce electricity from this facility in the
forward capacity auctions conducted by ISO-New England.\9\ Given this
limited remaining use of these units, combined with the fact that the
facility's current SCR NOX control systems already achieve a
high level of control, the cost of new controls per ton of emission
reduction achieved is not economically feasible for purposes of RACT.
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\8\ A copy of the press releases from Conservation Law
Foundation, Sierra Club, and Granite Shore Power announcing the
closure agreement is included in the docket for the rule.
\9\ The results of ISO New England's 17th Forward Capacity
Auction, which is for the time period June 1, 2026 through May 31,
2027, indicates that bids to offer power to the New England grid
from MK1 and MK2 were not accepted for this time period. See:
https://www.iso-ne.com/static-assets/documents/2023/03/fca_17_results_filing.pdf.
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Comment: Sierra Club commented that other states require lower
emissions limits for coal-fired power plants. In its comments, Sierra
Club asserted that several other states, including Pennsylvania, New
Jersey, Maryland, and Delaware, impose lower emission limits at coal-
fired power plants.
Response: EPA agrees that other states require lower emissions
limits for coal-fired cyclone boilers. However, as noted above, New
Hampshire and EPA have not identified coal-fired boilers that offer an
appropriate or equivalent comparison to the units at Merrimack Station.
Sierra Club points to lower short-term emission limits adopted by other
states for coal-fired boilers, such as Delaware's 0.125 lbs/MMBtu limit
based on a 24-hour averaging time, and Maryland's 0.10 lbs/MMBtu limit
which is also based on a 24-hour averaging time and includes all modes
of operation. However, none of the coal-fired boilers in these states
match the type of boiler and fuel type of Merrimack Station's boilers,
which as mentioned are bituminous fueled cyclone boilers operating only
SCR controls that were installed many years ago. The only coal-fired
electric utility boiler in Delaware is located at the Indian River
Generating Station in Dagsboro and is a dry-bottom, turbo-fired boiler.
Regarding Maryland, the coal-fired boiler located at the AES Warrior
Run Cogeneration facility in Cumberland is an atmospheric circulating
fluidized bed boiler, the two coal boilers at Brandon Shores are both
dry bottom boilers with circular wall burners, and the coal boiler at
Wagner Station is a supercritical steam boiler. Therefore, EPA
concludes from a technical perspective that limits deemed RACT for
these specific units in New
[[Page 34140]]
Hampshire \10\ should be higher than limits in Delaware and Maryland.
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\10\ RACT is defined, in part, as ``the lowest emissions
limitation a particular source is capable of meeting by the
application of control technology that is reasonably available
considering technological and economic feasibility'' (44 FR 53762;
September 17, 1979).
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Sierra Club also points to RACT limits for coal-fired boilers
located in Pennsylvania that EPA recently finalized with a Federal
Implementation Plan published in the Federal Register on August 31,
2022,\11\ as an example of more restrictive emissions limits in other
states relative to what New Hampshire has required for the coal units
at Merrimack Station. A number of factors differentiate the units at
Merrimack Station compared with those located in Pennsylvania. For
example, none of the Pennsylvania units are of the high-emitting,
cyclone boiler configuration as both units at Merrimack Station.
Additionally, the Merrimack Station boilers are much smaller than the
Pennsylvania units. Most of the units addressed in the Pennsylvania
RACT FIP are between 600 and 900 MW, whereas the Merrimack units are
around 100 MW and 300 MW. As a result of their smaller size, the
Merrimack units have considerably lower annual emissions. Over the past
five years (2019 through 2023), the total annual NOX
emissions from both Merrimack units ranges from 175 to 500 tons/year.
As a point of comparison, the Keystone and Conemaugh facilities in
Pennsylvania each had average annual NOX emissions over 4500
tpy since 2019. The low annual emissions at Merrimack combined with
their very low utilization and required stop of use in 2028 leads to
any additional controls at Merrimack being not economically feasible
for purposes of RACT.
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\11\ See 87 FR 53381.
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Comment: Sierra Club commented that recent air pollution transport
rules such as the Revised Cross-State Air Pollution Rule Update (RCU)
for the 2008 ozone NAAQS and the Good Neighbor Plan (GNP) for the 2015
ozone standard contain more restrictive emission rates than what New
Hampshire requires for NOX limits for MK1 and MK2.
Response: The requirements within EPA's transport rules do not
offer legitimate comparisons to the emission limits New Hampshire has
set as RACT limits for Merrimack Station's coal-fired cyclone boilers
for a number of reasons. First, regarding the RCU, EPA did not
establish short term emission limits for coal-fired EGU boilers within
that rule, but rather only imposed ozone season,\12\ mass-based
emissions budgets. These budgets were based in part on a statistical
analysis showing that coal-fired EGUs equipped with existing SCR are
capable of achieving an emissions rate of 0.08 lbs/MMBtu on a fleetwide
average and over an entire ozone season. Additionally, the RCU allows a
facility to remain in compliance if the facility holds sufficient
emissions allowances to cover the amount of emissions produced. See 86
FR 23056, 23090 (April 30, 2021). New Hampshire's RACT emissions limits
are structured much differently, requiring that the facility meet a
NOX emissions rate of 0.22 lbs/MMBtu on a short-term, 24-
hour averaging time basis. Additionally, the historical data New
Hampshire analyzed for these particular units indicate that this is
near the limit of what SCR at these units is capable of achieving. As
explained elsewhere in this notice, emissions limits with short
averaging times are more difficult to meet because there is less time
to offset emissions that occur while operating above the emissions
limit with emissions produced during times of operation below the
limit.
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\12\ The ozone season encompasses the 153-day period from May 1
to September 30.
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Regarding comparisons to the NOX reductions required of
electric utility boilers subject to the GNP, a statistical analysis
similar to the RCU of fleetwide emissions performance over an entire
ozone season informed the identification of emissions rates used to set
state-level EGU budgets. Thus, similar to the RCU as mentioned above,
these rates do not offer a good comparison to the short-term limits New
Hampshire requires for MK1 and MK2. Although the GNP, unlike the RCU,
adds an additional, short term, 24-hour average backstop daily rate of
0.14 lbs NOX/MMBtu for coal-fired boilers with SCR,\13\
there are substantial differences in how EPA established and will
implement that backstop rate within the trading program versus how New
Hampshire established and implements its NOX RACT limits for
Merrimack Station's coal-fired boilers. First, we note that the GNP's
24-hour backstop rate will only apply to emissions during the ozone
season that exceed by more than 50 tons a daily average NOX
emissions rate of 0.14 lb/MMBtu. New Hampshire's limits apply year-
round and do not excuse the first 50 tons, or any amount of emissions,
that exceed its emissions limits.\14\ Furthermore, the GNP's 24-hour
backstop rate, if exceeded beyond the 50 ton exemption mentioned above,
can be complied with via the surrender of emissions allowances at a 3
for 1 surrender ratio; New Hampshire's limits do not offer this type of
compliance option. Additionally, we note that EPA determined its 24-
hour backstop daily rate based on a review of the average emitting
characteristics of most coal fired boilers in operation during 2021.
New Hampshire determined the NOX RACT emission rates for the
Merrimack Station boilers based on the emitting and operational
characteristics of these specific units. In the GNP, the EPA observed
that even units considered to be running their controls optimally had
some days (most often less than 5% of days) where the rates were
higher. However, the emission increases on these days were minimal. EPA
used a similar methodology in employing the 95th percentile of observed
daily operating emissions rates in selecting the backstop daily
emissions rate for SCR-controlled coal boilers in the GNP.\15\ As an
example, for a unit with a seasonal rate of 0.08 lbs NOX/
MMBtu, EPA determined that it would be expected that, on average, about
4.7% of the daily rate values would be higher than 0.14 lb/MMBtu.
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\13\ See footnote 3.
\14\ As will be discussed later in this document, New Hampshire
imposed separate, mass-based emissions limits for days with a
startup or shutdown event.
\15\ See 88 FR 36654, 36792 (June 5, 2023). We note that in
contrast to the derivation of the GNP's daily limits, wherein EPA
concluded that SCR optimized units (i.e., units that were running
their SCR controls effectively) were those able to achieve a 0.08
lbs/MMBtu ozone season emission rate, NH's NOX RACT
evaluation points to the high percent reduction from uncontrolled
levels as an indicator of effective operation of SCR controls. Using
a 0.08 ozone season emission rate as a basis for setting emissions
limits for MK1 and MK2 would have been inappropriate because of
their much higher uncontrolled emission levels relative to the units
governed by the GNP.
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Comment: Sierra Club commented that NH's emissions limits for a
different coal-fired electrical generating facility in the state,
Schiller Station, are only slightly higher than those for Merrimack
Station, despite the fact that the Schiller Station units controlled by
SNCR, a less effective control strategy, inferring that Merrimack
Station's more capable SCR controls are not being as effectively run as
they should be.
Response: EPA agrees that New Hampshire has imposed NOX
emissions limits on the coal-fired boilers at Schiller Station of 0.25
lbs/MMBtu that are only slightly higher than the limits imposed on the
Merrimack Station units, despite the latter operating SCR controls, and
the former operating less effective SNCR controls. However, this is not
indicative of unduly lax
[[Page 34141]]
requirements for units MK1 and MK2 relative to the Schiller units, but
rather, points to the higher uncontrolled NOX emission rates
for the Merrimack Station units relative to the Schiller units.
According to Table 1.1-3 of AP-42, the uncontrolled NOX
emissions rate for Merrimack Station's bituminous fueled cyclone
boilers is 33 lbs of NOX per ton of coal burned, which is
the highest emission rate for any type of coal fired boiler listed
within the table.\16\ Schiller Station operates two dry-bottom, wall-
fired coal boilers, which AP-42 indicates have an uncontrolled
emissions rate of 22 lbs of NOX per ton of coal burned, and
a fluidized bed boiler, which AP-42 indicates has an uncontrolled
emissions rate of between 5.0 to 15.2 lbs of NOX per ton of
coal burned. Given the differences in uncontrolled emission rates and
NOX control technology of the coal-fired boilers at these
facilities, comparisons of the NOX emissions rates do not
offer an effective means of gauging the stringencies of the applicable
emissions rates. The Merrimack Station units operate the more costly,
more effective NOX control equipment compared to what the
Schiller Station units run; technical resources that describe the
control effectiveness of various NOX emission reduction
control techniques rank SCR control systems higher than SNCR control
systems.\17\
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\16\ See Table 1.1-3, Emission Factors for SOX,
NOX, and CO From Bituminous and Subbituminous Coal
Combustion, within section 1.1 of AP-42: https://www.epa.gov/sites/default/files/2020-09/documents/1.1_bituminous_and_subbituminous_coal_combustion.pdf.
\17\ See, for example, Table 1.1-2, NOX Control
Options for Coal-fired Boilers within Section 1.1, Bituminous and
Subbituminous Coal Combustion, of AP-42, and EPA's Air Pollution
Control Technology Fact Sheets for SNCR and SCR control systems,
included within the docket for this action.
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Comment: Sierra Club commented that in light of recent information
showing that SCR control systems can be operated at low-temperature
levels that occur during periods of startup and shutdown with no
detriment to control efficacy or longevity, New Hampshire does not need
to allow the units to emit more on days when these operating modes
occur by providing daily emission limits of 4.0 and 11.5 tons per day
for MK1 and MK2, respectively.
Response: In the aforementioned response to comments received on
its proposed Regional Haze SIP, New Hampshire notes that approximately
one fourth of the operating hours in the year prior to the
establishment of the NOX RACT emission rates in question
were hours spent in startup or shutdown modes when operating
conditions, in particular temperature, did not permit the operation of
the SCR control systems. The state therefore concluded that setting one
overall emissions limit that combined the hours spent in startup and
shutdown mode, during which the SCR controls would not operate, with
the hours spent in steady state operation, during which the SCR
controls would operate, would have necessitated issuance of an all-
encompassing emissions limit higher than the limit New Hampshire
ultimately decided upon for times of steady state operation. By
choosing to adopt separate limits for these operating modes, New
Hampshire's emissions rate structure requires that MK1 and MK2 meet a
lower emissions rate for the majority of the time it is operating, that
being operation under steady state conditions with the SCR control
equipment functioning. A separate alternate emission limit (AEL)
applicable during startup and shutdown modes ensures that the emissions
that occur during those times are also subject to an emissions cap as
well as recordkeeping requirements to document the dates and time spent
in startup or shutdown mode. As noted within the update to section 2 of
the technical support document included within the docket for this
action, the AEL in conjunction with requirements contained within Env-A
1300 and the facility's Title V operating permit mean that the SCRs
must be turned on expeditiously once high levels of coal loading begin
in order to avoid exceeding the tons/calendar day limit of the AEL.
Sierra Club refers to a sorbent injection technology that can
reduce the operating temperature range of the SCR and potentially
reduce NOX emissions at low loads. NHDES reviewed the
provided references, which describe the technology as allowing the
coal-fired boilers operated by Duke Power's Gibson facility to operate
its SCRs at a lower temperature than would otherwise be possible, and
also enable the coal boilers to run at low loads while still minimizing
emissions. NHDES notes, however, that MK1 and MK2 SCRs are not designed
to operate at lower temperatures, nor are the boilers intended to
operate at low electrical output loads, and so even if modifications
were made such that the SCR control equipment could function at lower
temperature there would be little benefit, from an emissions reduction
perspective, to installing additional controls to enable this. The
small benefit in emissions reductions for operating the SCR at lower
temperatures is partially due to the level and averaging period of the
AEL, which significantly limits the time that these boilers can operate
with high fuel input without the SCRs, and therefore limits the amount
of total emissions because the units would exceed the 4 tons per day
emission limit if they operated with high fuel input without the SCRs
in operation.\18\ Therefore, NHDES concluded that a lowering of the
temperature at which the SCR controls could operate during startup and
shutdown would not justify the significant capital costs it would take
to install the new control technology Sierra Club mentions. New
Hampshire notes that in 2021, MK1 and MK2 operated for approximately
2,155 hours and were started up approximately 26 times. Assuming that
the sorbent injection technology mentioned in Sierra Club's comments
could lower the temperature at which MK1 and MK2 could operate their
SCR controls such that they could be used for an additional hour during
startup, this would have resulted in a relatively minor, incremental
emission reductions \19\ by allowing 26 additional hours of SCR
operating time out of 2,155 overall boiler operating hours.
---------------------------------------------------------------------------
\18\ For a further explanation and example of this behavior, see
the TSD that accompanies this final action.
\19\ EPA reviewed the difference in emissions between the last
hour of non-SCR operation and the first hour of SCR operation and
found that if MK1 could have begun SCR controls 1 hour earlier
during each startup in 2021, 3.4 tons of NOX would have
been prevented, and for MK2, 8.6 tons would have been prevented.
---------------------------------------------------------------------------
We have reviewed Sierra Club's comment that additional emissions
control technology be required for startup and shutdown operations, and
New Hampshire's rationale for not requiring it, and agree with the
state's conclusion that the additional cost of evaluating, installing,
and operating control technology to limit emissions during startup and
shutdown is unlikely to be economically feasible given the minimal
amount of emissions it would curtail. Furthermore, the recordkeeping
and reporting requirements of New Hampshire's NOX RACT
regulation enable the state to effectively oversee operations at the
facility, including operations during startup and shutdown. For
example, the state's oversight requirements recently led to the
issuance of an August 23, 2023 letter requesting more information
regarding four exceedances of the startup emissions limit that occurred
between December 8, 2021, and July 7, 2023.\20\ A
[[Page 34142]]
total of 16.4 tons of excess emissions occurred on these days, and the
state is currently evaluating the appropriate enforcement response to
these violations.
---------------------------------------------------------------------------
\20\ A copy of New Hampshire's August 23, 2023 letter to Granite
Shore Power is included in the docket for this action.
---------------------------------------------------------------------------
Comment: Sierra Club also commented that New Hampshire's
requirements are not sufficient for regional haze purposes.
Response: This comment is not germane to the subject matter of this
action which pertains to New Hampshire's NOX RACT
requirements for coal-fired cyclone boilers and does not address
regional haze requirements. Therefore, EPA is not addressing this
comment here.
III. Final Action
EPA is approving RACT requirements limiting NOX
emissions from coal-fired cyclone boilers powering electrical
generating units that are codified within New Hampshire Air Pollution
Control Regulation Env-A 1300: Nitrogen Oxides (NOX) RACT,
portions of New Hampshire's NOX RACT certifications for the
2008 and 2015 ozone standards that pertain to requirements for coal-
fired cyclone boilers, and withdrawal from the SIP of two previously
issued RACT orders containing emission limits for this equipment that
are less stringent than what is contained within the provisions of Env-
A 1300 that we are approving within this action.
IV. Incorporation by Reference
In this rule, the EPA is finalizing regulatory text that includes
incorporation by reference. In accordance with requirements of 1 CFR
51.5, the EPA is finalizing the incorporation by reference of portions
of New Hampshire Air Pollution Control Regulation Env-A 1300, Nitrogen
Oxides (NOX) RACT; specifically, incorporating by reference
Env-A 1303.06(b) and (c) pertaining to the coal-fired cyclone boilers
at Merrimack Station, as described in the amendments to 40 CFR part 52
set forth below. The EPA has made, and will continue to make, these
documents generally available through https://www.regulations.gov and
at the EPA Region 1 Office (please contact the person identified in the
FOR FURTHER INFORMATION CONTACT section of this preamble for more
information). Therefore, these materials have been approved by EPA for
inclusion in the State implementation plan, have been incorporated by
reference by EPA into that plan, are fully federally enforceable under
sections 110 and 113 of the CAA as of the effective date of the final
rulemaking of EPA's approval, and will be incorporated by reference in
the next update to the SIP compilation.\21\
---------------------------------------------------------------------------
\21\ 62 FR 27968 (May 22, 1997).
---------------------------------------------------------------------------
EPA is also finalizing the removal of provisions within Table (d)
of 52.1520 pertaining to these coal-fired cyclone boilers by removing
Permits ``Order ARD-97-001: Source specific NOX RACT Order
for Public Service of New Hampshire, Bow, NH; state effective date 4/
14/1997'' and ``Order ARD-98-001: Source-specific NOX RACT
order and discrete emission reduction protocols for Public Service of
New Hampshire; state effective date 7/17/1998'' as described in the
amendments to 40 CFR part 52 set forth below.
V. Statutory and Executive Order Reviews
Under the Clean Air Act, the Administrator is required to approve a
SIP submission that complies with the provisions of the Act and
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a).
Thus, in reviewing SIP submissions, EPA's role is to approve state
choices, provided that they meet the criteria of the Clean Air Act.
Accordingly, this action merely approves state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this action:
Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Orders 12866 (58
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
Is not subject to requirements of Section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the Clean Air Act.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian tribe has
demonstrated that a tribe has jurisdiction. In those areas of Indian
country, the rule does not have tribal implications and will not impose
substantial direct costs on tribal governments or preempt tribal law as
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
Executive Order 12898 (Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations, 59 FR 7629,
Feb. 16, 1994) directs Federal agencies to identify and address
``disproportionately high and adverse human health or environmental
effects'' of their actions on minority populations and low-income
populations to the greatest extent practicable and permitted by law.
EPA defines environmental justice (EJ) as ``the fair treatment and
meaningful involvement of all people regardless of race, color,
national origin, or income with respect to the development,
implementation, and enforcement of environmental laws, regulations, and
policies.'' EPA further defines the term fair treatment to mean that
``no group of people should bear a disproportionate burden of
environmental harms and risks, including those resulting from the
negative environmental consequences of industrial, governmental, and
commercial operations or programs and policies.''
The New Hampshire Department of Environmental Services did not
evaluate environmental justice considerations as part of its SIP
submittal; the CAA and applicable implementing regulations neither
prohibit nor require such an evaluation. EPA did not perform an EJ
analysis and did not consider EJ in this action. Due to the nature of
the action being taken here, this action is expected to have a neutral
to positive impact on the air quality of the affected area.
Consideration of EJ is not required as part of this action, and there
is no information in the record inconsistent with the stated goal of
E.O. 12898 of achieving environmental justice for people of color, low-
income populations, and Indigenous peoples.
The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a
[[Page 34143]]
copy of the rule, to each House of the Congress and to the Comptroller
General of the United States. EPA will submit a report containing this
action and other required information to the U.S. Senate, the U.S.
House of Representatives, and the Comptroller General of the United
States prior to publication of the rule in the Federal Register. A
major rule cannot take effect until 60 days after it is published in
the Federal Register. This action is not a ``major rule'' as defined by
5 U.S.C. 804(2).
Under section 307(b)(1) of the Clean Air Act, petitions for
judicial review of this action must be filed in the United States Court
of Appeals for the appropriate circuit by July 1, 2024. Filing a
petition for reconsideration by the Administrator of this final rule
does not affect the finality of this action for the purposes of
judicial review nor does it extend the time within which a petition for
judicial review may be filed, and shall not postpone the effectiveness
of such rule or action. This action may not be challenged later in
proceedings to enforce its requirements. (See section 307(b)(2).)
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Nitrogen dioxide, Ozone.
Dated: April 18, 2024.
David Cash,
Regional Administrator, EPA Region 1.
Part 52 of chapter I, title 40 of the Code of Federal Regulations
is amended as follows:
PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS
0
1. The authority citation for part 52 continues to read as follows:
Authority: 42 U.S.C. 7401 et seq.
Subpart EE--New Hampshire
0
2. In Sec. 52.1520:
0
a. Amend the table in paragraph (c) by revising the entry for ``Env-A
1300'';
0
b. Amend the table in paragraph (d) by removing the entries for
``Source specific NOX RACT order for Public Service of New
Hampshire, Bow, NH'' and ``Source-specific NOX RACT order
and discrete emission reduction protocols for Public Service of New
Hampshire''; and
0
c. Amend the table in paragraph (e) by revising the entry for
``Certifications for RACT for the 2008 and 2015 ozone standards''.
The revisions read as follows:
Sec. 52.1520 Identification of plan.
* * * * *
(c) * * *
EPA-Approved New Hampshire Regulations
----------------------------------------------------------------------------------------------------------------
State effective EPA approval date
State citation Title/subject date \1\ Explanations
----------------------------------------------------------------------------------------------------------------
* * * * * * *
Env-A 1300..................... NOX RACT......... 8/15/2018 and 9/6/2023, 88 FR Regulation, effective
3/20/2023 60893. 8/15/2018, containing
emissions limits and
other requirements
for stationary
sources of nitrogen
oxides approved
except for sections
pertaining to coal-
fired cyclone boilers
at Env-A 1303.06(b)
and (c). Revisions
made to Env-A 1303.02
and 1303.04.
effective 3/20/2023.
8/15/2018 4/30/2024 [Insert Requirements
Federal Register pertaining to coal-
citation]. fired cyclone boilers
at Env-A 1303.06(b)
and (c).
* * * * * * *
----------------------------------------------------------------------------------------------------------------
\1\ In order to determine the EPA effective date for a specific provision listed in this table, consult the
Federal Register notice cited in this column for the particular provision.
(e) * * *
New Hampshire NonRegulatory
----------------------------------------------------------------------------------------------------------------
Applicable
Name of nonregulatory SIP geographic or State submittal
provision nonattainment date/effective EPA approved date Explanations
area date
----------------------------------------------------------------------------------------------------------------
* * * * * * *
Certifications for RACT for the Statewide........ 9/6/2018 9/6/2023, 88 FR RACT certifications
2008 and 2015 ozone standards. 60893. for stationary
sources of VOC and
NOX approved for
purposes of the 2008
and 2015 ozone
standards except for
NOX RACT requirements
pertaining to coal-
fired cyclone
boilers.
9/6/2018 4/30/2024 [Insert NOX RACT
Federal Register certifications for
citation]. the 2008 and 2015
ozone standards
pertaining to coal-
fired cyclone
boilers.
* * * * * * *
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[[Page 34144]]
[FR Doc. 2024-08713 Filed 4-29-24; 8:45 am]
BILLING CODE 6560-50-P