analysis does not give greater weight to one factor over another;
rather, we considered all four factors fully, revealing that the cost
factor, which included visibility improvement consideration, was the
most determinative in our decisions. The American Corn Growers Ass'n v.
EPA case is inapposite. There, the D.C. Circuit Court faulted how EPA
assessed the statutory fifth factor of visibility improvement in a BART
determination (not a reasonable progress determination) by using a
regional, multi-source, group approach to assessing the visibility
improvement factor, while assessing the other four statutory BART
factors on a source-specific basis. Here, not only is the analysis at
issue not being performed under BART, but we did not give greater
weight to our consideration of visibility improvement within the cost
factor, or consider the cost factor in a different fashion from the
other three reasonable progress factors.
    Comment: Some commenters stated that regional haze is the
contribution of numerous emission sources to visibility impairment and
that, while the contribution from any single source may be
``insignificant,'' the aggregate impact from all sources is
significant. These commenters argued that, by using the Q/d screening
metric, the EPA already took potential visibility impacts (and benefits
of control) into account. They argued that the EPA cannot use
visibility again during the four-factor analysis as an ``off-ramp'' to
not control a source. Furthermore, the EPA should not break a facility
down into its constituent parts because doing so can diminish each
individual impact to the point where it becomes relatively
insignificant. Such a ``divide and exempt'' approach is contrary to
Congress' goal that Class I areas eventually return to natural
visibility conditions. One commenter stated that the EPA should have
conducted four-factor analyses for all 38 facilities identified in the
Q/d analysis.
    Response: We agree that regional haze is, by definition, visibility
impairment caused by numerous emission sources. We also agree that,
while some sources may have very small visibility impacts, aggregate
impacts can be significant. However, while there are undoubtedly
thousands of sources within Texas that individually have small
contributions to regional haze, there are also many sources that, even
in isolation, have relatively large visibility impacts. In this first
planning period, we identified the most significant sources that impact
visibility, determined whether cost-effective controls were available
for these sources, and balanced the costs of those controls against
their visibility benefits. As we discussed in more detail above, if we
had adopted the commenters' suggestion and controlled all large sources
where cost-effective controls were available, we likely would have
controlled many additional sources. Given the iterative nature of the
regional haze program, we think that it was a reasonable approach to
require only those cost-effective controls with the largest benefits
this planning period. We expect that Texas will control additional
sources, which by then will be the largest contributors to impairment,
during future planning periods.
    As we explain further in supporting documents, we also disagree
with the commenter's suggestion that we should have screened only by
using the Q/d metric. A Q/d analysis compares a source's emissions and
distance to nearby Class I areas to provide an initial estimate of the
potential visibility impacts of those sources. After conducting our Q/d
analysis, we then used photochemical modeling to estimate the
visibility impacts of this set of sources in a much more refined manner
that accounts for chemistry, meteorological conditions, and stack
parameters in addition to emissions and location. The results of our
modeling indicated that a subset of 38 facilities were the primary
contributors to visibility impairment at each Class I area. We then
used the modeling results to narrow the group of sources further
because it was reasonable to conduct a

full four-factor analysis only for the subset of sources with the
largest facility-and unit-level visibility impacts, as described in
detail in our supporting documents.

E. Consultation Between Oklahoma and Texas

    Comment: The regulations require that Texas' long-term strategy
reflect the emission reductions requested and agreed to by the CENRAP
states. EPA points to no flaws in the CENRAP regional planning process
in which Texas and Oklahoma participated together. The EPA asserts that
the TCEQ should have provided information necessary to identify
reasonable reductions, which the Regional Haze Rule does not require.
Oklahoma did not request additional controls on Texas sources or
disagree with Texas' determination that no additional controls were
warranted during the first planning period.
    Nonetheless, the EPA arbitrarily disapproved the Texas consultation
process with Oklahoma without reference to its rules, guidance, and
prior SIP approvals. The proposal never details what information
Oklahoma lacked in establishing its reasonable progress goals, and EPA
must provide a more adequate explanation of how additional information
would have changed Oklahoma's ultimate determination that additional
controls on Texas sources would not move the Wichita Mountains
perceptibly closer to its regional haze goals.
    Response: We disagree that participation alone in a Regional
Planning Organization (RPO) process (here CENRAP) will always be enough
to meet the requirements for consultation under the Regional Haze Rule.
The rule does not negate the requirement that a state have a complete
and technically adequate analysis so that consultations are well
informed. The RPOs, such as CENRAP, provided technical analyses,
including emission inventory development and air quality modeling to
project future visibility conditions and additional information on
sources of visibility impairment to facilitate consultations and
support the development of the states' regional haze SIPs.
    Although Texas participated in CENRAP, it retained the duty to do
whatever additional analysis was necessary to fully address the
requirements of the Regional Haze Rule for addressing its long-term
strategy and setting its reasonable progress goals. While the long-term
strategy requirements allow a state to rely on the RPO technical
analysis, that is true only to the extent it provides the necessary
information. A state must address any gaps in that analysis. For Texas,
inadequate information existed not only for the reasonable progress
analysis for its own Class I areas, but also for the long-term strategy
development for addressing significant impacts at the Wichita
Mountains. CENRAP was not required, nor did it provide state-specific
analyses and information on the cost-effectiveness and visibility
benefits of potential control strategies under consideration by each
state to address the specific sources or groups of sources within that
state that have the largest visibility impacts. Rather, CENRAP provided
more general information on overall projected visibility conditions,
potential controls and associated costs for some sources and the
potential benefit of regional emission reductions to inform the
development of potential control strategies that may require additional
analysis.\76\ For example, while the CENRAP analysis identified that
impacts from EGUs in Texas were significant, it did not provide a
refined analysis to fully assess the cost-effectiveness and visibility
benefits of controlling those sources, including not providing
information on the cost-effectiveness of scrubber upgrades for those
sources with existing, underperforming scrubbers. As Texas states in
its regional haze SIP, ``While Texas participates in CENRAP and
benefits from the technical work coordinated by the RPO, Texas has sole
responsibility and authority for the development and content of its
Regional Haze SIP.'' \77\
---------------------------------------------------------------------------

    \76\ CENRAP conducted a control sensitivity analysis to evaluate
the impact of point source emission reductions across all CENRAP
states given a maximum dollar per control level of $5,000/ton;
however, the results ``were intended to be a starting point for
control discussions that would require much greater refinement.''
Technical Support Document for CENRAP Emissions and Air Quality
Modeling to Support Regional Haze State Implementation Plans,
September 12, 2007 at 2-37).
    \77\ 2009 Texas Regional Haze SIP at 3-1.
---------------------------------------------------------------------------

    Recognizing that the information made available by CENRAP indicated
the significant impact of Texas emissions and potential for cost-
effective controls, Texas used the CENRAP analysis as a starting point,
and performed supplemental analysis for both its reasonable progress
and long-term strategy demonstrations. However, that additional
technical analysis performed by Texas was flawed and therefore did not
provide the type of information necessary to fully evaluate the
reasonableness of controls at Texas sources with the largest potential
to impact visibility at its own Class I areas and the Wichita
Mountains. Allowing this lack of adequate information to continue was a
critical misstep for ODEQ in setting its reasonable progress goals, and
a critical misstep for Texas when determining its fair share of
emissions reductions under the long-term strategy requirement. The
plain language of the CAA requires that states consider the four
factors used in determining reasonable progress in developing the
technical basis for the reasonable progress goals both in their own
Class I areas and downwind Class I areas. Such documentation is
necessary so that interstate consultations can proceed on an informed
basis, and so that downwind states can properly assess whether any
additional upwind emissions reductions are necessary to achieve
reasonable progress at their Class I areas. Therefore, Texas had an
obligation to provide appropriate information to Oklahoma so it could
establish a proper progress goal for the Wichita Mountains. Further,
Texas had an obligation to conduct an appropriate technical analysis,
and demonstrate through that analysis (required under paragraph
(d)(3)(ii)), that it provided its fair share of emissions reductions to
Oklahoma. In summary, Texas was required through the consultation
process to provide Oklahoma the information it needed to establish its
reasonable progress goals for the Wichita Mountains, and it failed to
do so.
    Comment: Oklahoma possessed more than adequate information about
impacts and potential controls but correctly decided it was not
reasonable to request any further reductions from Texas sources during
the first planning period. Oklahoma was in agreement with Texas on the
goal and measures for the Wichita Mountains. EPA may disagree with that
choice in hindsight and may wish Oklahoma's and Texas' agreement was
different, but that is an unlawful basis for disapproving Oklahoma's
reasonable progress consultation with Texas and disapproving Oklahoma's
reasonable progress goals.
    Response: While we agree that Oklahoma possessed more than adequate
information from the CENRAP analyses about impacts from Texas sources
at a certain level of aggregation, and some knowledge concerning
potential controls for some of these sources, we do not agree that it
was reasonable for Oklahoma to stop at this point. Despite the
information it did have, Oklahoma never explicitly asked Texas for
reductions even though there was clear evidence from the CENRAP
analyses that Texas sources, particularly EGUs in northeast Texas, were

significantly impacting the Wichita Mountains and that cost-effective
controls were likely available on some of these sources.
    The Regional Haze Rule required that Oklahoma use the consultation
process under 40 CFR 51.308(d)(1)(iv) in the development of reasonable
progress goals in tandem with Texas. Nevertheless, throughout the
consultations, Oklahoma failed to explicitly request that Texas further
investigate whether reasonable controls were available or that Texas
reduce emissions from these significantly impacting sources to ensure
that all reasonable measures to improve visibility were included in
Texas' long-term strategy and incorporated into Oklahoma's reasonable
progress goals for the Wichita Mountains. This failure resulted in the
development of improper reasonable progress goals for the Wichita
Mountains.
    Comment: Even if EPA's disapproval of Oklahoma's reasonable
progress goals were authorized and supported, that disapproval does not
allow EPA to disapprove Texas' long-term strategy. Regardless of EPA's
view of Oklahoma's reasonable progress goals for the Wichita Mountains,
it is undisputed that Texas' SIP includes the measures necessary to
secure Texas' agreed-to apportionment of emission reductions to meet
the reasonable progress goals for the Wichita Mountains established by
Oklahoma, and thus EPA must approve Texas' SIP.
    Response: We disagree that disapproval of Oklahoma's reasonable
progress goals for the Wichita Mountains does not allow us to
disapprove Texas' long-term strategy. We are disapproving the Texas
long-term strategy because the analysis underlying it is technically
flawed. Because of these flaws, Texas' SIP submittal does not include
all the measures necessary to secure its apportionment of the emission
reductions needed to meet the progress goal that should account for all
reasonable control measures for the Wichita Mountains, or its own Class
I areas. We are disapproving the Oklahoma reasonable progress goals for
the Wichita Mountains not because of the technically flawed Texas long-
term strategy, but because Oklahoma's consultations with Texas were
flawed, which prevented it from adequately developing its reasonable
progress goals for the Wichita Mountains. Also, because Oklahoma's
consultations with Texas were flawed, Oklahoma did not adequately
consider the emission reduction measures necessary to achieve the
uniform rate of progress for the Wichita Mountains and did not
adequately demonstrate that the reasonable progress goals it
established were reasonable based on the four statutory factors. See
our previous responses concerning the comments on Texas allegedly
meeting the ``agreed-to apportionment.''
    Comment: EPA never raised any of the concerns it asserts and it
never second-guessed the process or the data that the states were
developing--as it does now, years after that process has been completed
and on the eve of the next planning period. In truth, Texas and
Oklahoma did exactly what EPA encouraged them to do.
    Response: Our task under the CAA is to review a SIP once it is
formally submitted by the state and determine if it meets the CAA and
our rules. There is no requirement in the CAA that we must review,
evaluate, and comment on a state's proposed SIP revision before it is
formally submitted to us. Nevertheless, we note that we sent comment
letters to Texas and Oklahoma during their public comment periods,
raising many of the issues presented herein. We stated that Texas
should specifically demonstrate that it included all measures necessary
to obtain its share of the emission reductions necessary for achieving
reasonable progress in the Wichita Mountains and document its technical
basis. Furthermore, we stated that the Texas reasonable progress/long-
term strategy technical analysis raised concerns about whether it
appropriately evaluated whether there were additional reasonable
controls available to help reduce its impact on the Wichita Mountains.
For Oklahoma, we stated it did not appear that ODEQ actually requested
reductions from Texas and we urged Oklahoma to ensure Texas was aware
of its sources' impact and encourage reductions as necessary. In both
letters, we stated that additional concerns would surface during the
review of the final SIP submittals.
    Comment: EPA's consultation disapprovals of Oklahoma and Texas are
the first time EPA has disapproved a state regional haze consultation.
This new approach of second-guessing regional agreements--years after
they are reached and implemented--would undermine and chill the
regional planning process, and discourage states from participating.
    Response: We disagree that this is a new approach on the
consultation requirements and we also disagree that our position
undermines or chills the regional planning process. While our
regulations allow states to work together in RPOs, like CENRAP, this is
not a stopping point for states to fall back on as a rationale not to
meet the CAA and Regional Haze Rule. We have not disapproved other
states' reasonable progress/long-term strategy consultation processes
because the particular facts of the situation for Texas and Oklahoma
did not arise. We believe our clarification that upwind states have an
obligation to reasonably assess potential control measures to address
impacts in Class I areas in downwind states will encourage states to
work together to address regional haze.

F. Source Category and Individual Source Modeling

    Comment: EPA proposed to disapprove Texas' regional haze SIP
because EPA determined that Texas was required to conduct a source-
specific analysis of certain facilities to meet the reasonable progress
requirements. EPA guidance and judicial precedent have stated that a
source-specific analysis or source-by-source demonstration is not
required to determine reasonable progress.
    Response: We disagree with these comments as our proposal to
disapprove the SIP was decidedly not based on the supposed use of a
source category-based analysis by Texas. Therefore, these comments have
not accurately described the proposed basis of disapproval. We
understand many of these comments arose because our proposal included a
statement that ``individual sources were not considered by the TCEQ.''
This statement was not offered to propose a basis for disapproval, but
we understand it is susceptible to being taken out of context
(particularly in consideration of the comments received). It is perhaps
more plain to state that individual sources were not effectively
considered by the TCEQ. As our proposal and the Texas SIP itself make
clear, Texas did, in fact, partially evaluate controls for certain
individual sources. In evaluating these controls, Texas employed a
large, superficially refined control set consisting of a mix of large
and small sources from a number of different source categories located
within varying distances of Class I areas. It did assess individual
source data for some factors such that we do not necessarily agree with
commenters who brand it a ``source category analysis.''
    Whatever its label, we proposed to disapprove Texas' reasonable
progress analysis because it was flawed in several specific ways. A
primary flaw was that the control set was over-inclusive. It included
controls on sources that served to increase the total cost with little
visibility benefit. As was

noted in our proposal,\78\ Texas adopted this approach despite evidence
in the record of identified source-specific, cost-effective controls
that would have resulted in large emission reductions on certain EGUs,
and despite source apportionment modeling that identified large impacts
from EGU sources in northeast Texas. Our proposal explained that this
approach obscured benefits that might be obtained from individual
sources and only considered aggregated costs. As we also explained, the
submitted analysis failed to study or consider scrubber upgrade
candidates. It was accordingly under-inclusive of large, highly cost-
effective emissions reductions that would lead to significant
improvements in visibility. These points are validated by the technical
record for this FIP.
---------------------------------------------------------------------------

    \78\ 79 FR 74838 (``[W]e believe that individual benefits were
masked by the inclusion of those controls with little visibility
benefit that only served to increase the total cost figures.'')
---------------------------------------------------------------------------

    Therefore, whether the state's analysis is labelled a source
category analysis, an analysis of multiple individual sources, or some
hybrid, we conclude that it contained serious deficiencies that would
materially affect the outcome of the state's SIP process. As a result,
we conclude this component of the SIP requires disapproval.
    Finally, it bears noting that the approach we have taken in our FIP
to identifying appropriate controls does not dictate the approach that
Texas or any other state must take to assess controls. Given Texas'
size and the range of distances from point sources to Class I areas,
the mix of controls at EGUs and other large point sources in the state,
and the overall significance of the impacts from these point sources,
we considered it appropriate to undertake a source specific analysis to
avoid the potential for over-controlling sources.\79\ In some
circumstances, depending on the types of sources at issue, the impacts
from these sources relative to other causes of visibility impairment,
the types of controls under consideration, and other such factors, a
source category approach can be appropriate. Ultimately, however, while
there is flexibility in available analytical approaches, states cannot
adopt an approach to reasonable progress, which by its nature overlooks
cost-effective controls that would otherwise be viewed as being
beneficial.
---------------------------------------------------------------------------

    \79\ On this point, it also bears noting that Texas' EGUs
operate within a state that is at least three times larger than 38
of the states and a full 60% larger than California, the next
largest of the contiguous states.
---------------------------------------------------------------------------

    Comment: Because of guidance and precedent that ``source category''
analyses can be appropriate, individual sources or point sources cannot
be subject to source-specific controls to meet reasonable progress.
Individual sources can be subject to control for purposes of addressing
BART or RAVI requirements but additional, source-specific controls may
not lawfully be imposed.
    Response: We disagree with the argument that, because a source
category analysis may be appropriate in some circumstances, sources
cannot be subject to source-specific controls to ensure reasonable
progress toward improving visibility. It is unclear how a state would
develop a SIP containing ``emission limits, schedules of compliance,
and other measures may be necessary to make reasonable progress,'' as
required by CAA section 169(A)(b)(2), without the option of source-
specific controls going forward. There is nothing in the visibility
provisions of the CAA or the Regional Haze Rule suggesting otherwise.
    Comment: Information on FGD scrubber upgrades cannot be used to
disapprove the SIP because that information was acquired through EPA's
authority to obtain information under CAA section 114, but the state
has no equivalent corresponding authority. EPA comment letters and
communications in past years had not informed the state of the
importance of analyzing scrubber upgrades.
    Response: Neither of these observations would justify our approving
a flawed component of a SIP revision--in this case an analysis within
that SIP revision--that, among other things, had unreasonably
overlooked the option of FGD upgrades. Our 2005 BART rule discussed the
state evaluation of scrubber upgrades in several places.\80\ The
technical information in our proposal validates FGD upgrades as an
option that should have been considered, and we consider this technical
record to have been reinforced and further validated with additional
information and comments provided in support of the proposal. Even as
we acknowledge that the TCEQ does not have authority (or any present
delegation of authority) to request information under CAA section 114,
this is not any kind of determinative limitation on the state's
technical and regulatory capacities and tools for producing and
developing information on an air pollution control measure such as FGD
upgrades. Texas has engaged in air quality control planning and air
pollution prevention under the CAA for decades, and the Texas agency or
agencies responsible for SIP adoption and implementation are required
to possess the necessary legal authority under state law to adopt and
implement all SIP measures.\81\ Consequently, in this case, the TCEQ
bore the responsibility of developing or requesting information needed
to properly assess scrubber upgrades. Lastly, as we state above, any
past EPA comment letters would be intended to be helpful to the
improvement of any SIP revision that is under development, but they do
not constitute agency action on that SIP revision or constitute any
assurance of positive action on that revision upon submission and
review. Instead and as always, EPA has to formally discharge its
responsibilities to review any SIP submittal under the provisions of
CAA section 110(k). Accordingly, the issue of TCEQ's knowledge, notice,
or lack thereof on FGD scrubber upgrades cannot be resolved in any way
that would shield the SIP revision from this basis for disapproval.
---------------------------------------------------------------------------

    \80\ See for instance 70 FR 39171: ``You should evaluate
scrubber upgrade options based on the 5 step BART analysis
process.''
    \81\ CAA section 110(a)(2)(E); 42 U.S.C. 7410(a)(2)(E)
(requiring assurances of ``. . . adequate, personnel, funding, and
authority under State . . . law to carry out'' SIP requirements);
Section 2.1(c) of appendix V to 40 CFR part 51.
---------------------------------------------------------------------------

G. Constitutional Law

    One commenter cited to the Commerce Clause, Fifth Amendment and
Constitutional non-delegation principles in support of its contention
that EPA should not be able to regulate sources under our regional haze
program. We disagree with these comments. First, under the Commerce
Clause, the commenter argues that we cannot regulate regional haze on
the theory that regulated conduct--such as ``carbon emissions'' from
coal-fired power plants--will have some effect on interstate commerce.
We disagree with the comment because owners and operators of the Texas
sources subject to this regional haze FIP are engaged in economic
activities (the operation of coal-fired power plants) that cause haze-
forming air pollution to travel into other states and substantially
affect interstate commerce. Each of the Federal Class I areas receives
substantial numbers of visitors, including those from out-of-state,
each year. Our regulation of these sources of visibility impairing
pollution pursuant to the CAA is squarely within the Federal
government's Commerce Clause authority. Our regulation of emissions
from coal-fired power plants, which cause and contribute to regional
haze in multiple states, to fill a gap left by disapproval of a SIP
seeks to fulfill

the regional haze provisions of the CAA, which in turn are
constitutional exercises of Congress's power under the Commerce Clause
of the U.S. Constitution.
    Second, the commenter contends that our Regional Haze Rule suffers
from a non-delegation problem. We disagree. The CAA's visibility
provisions provide extensive intelligible principles that guide our
exercise of discretion. CAA section 169A, as well as other provisions,
required us to promulgate regulations directing the states to revise
their SIPs to include emission limits and other measures as necessary
to make ``reasonable progress.'' \82\ Congress defined reasonable
progress to be the consideration of four statutory factors, including
cost and energy impacts.\83\ Congress also directed our regulations to
require BART for a specific universe of older sources, and again
provided a set of statutory factors states must consider when
determining what control technology constitutes BART.\84\ These two
sets of statutory factors, among several other provisions and
definitions in CAA section 169A that provide specific instructions to
EPA and states, clearly constitute intelligible principles under the
framework set forth in the case cited by the commenter. The Regional
Haze Rule, which we promulgated pursuant to the statutory mandate in
CAA section 169A, reflects these same intelligible principles and has
been upheld by the D.C. Circuit Court.
---------------------------------------------------------------------------

    \82\ 42 U.S.C. 7491(b)(2).
    \83\ Id. at 7491(g)(1).
    \84\ Id. at 7491(b)(2)(A) & (g)(2).
---------------------------------------------------------------------------

    Third, a commenter claims that the EPA has commandeered the states
in violation of the Fifth Amendment of the Constitution. We disagree
with this comment. The U.S. Supreme Court has held that, ``the Federal
Government may not compel the states to implement Federal regulatory
programs.'' \85\ The CAA in no way compels a state to implement Federal
regulatory programs. The CAA, instead, authorizes the EPA to promulgate
and administer a FIP if a state fails to submit an adequate SIP.\86\
The EPA will implement the FIP, with no actions required by any part of
the government of Texas.
---------------------------------------------------------------------------

    \85\ Printz v. United States, 521 U.S. 898, 925 (1997).
    \86\ 42 U.S.C. 7410(c)(1)(A).
---------------------------------------------------------------------------

H. Stay of Effective Date, Consolidated Appropriations Act, and
Executive Orders 13405 and 13211

    Comment: Any final action should stay the effectiveness and
effective date of the action or establish a delayed effective date to
allow for ``judicial vetting'' of EPA's determinations.
    Response: We have reviewed these requests and do not agree that
taking these measures with our final rule would be appropriate. Our
final rule initiates the effectiveness of the action to ensure the
requirements of the CAA are carried into effect. This result is
consistent with the CAA and with the regulatory rulemaking process more
generally. We note that CAA section 307(d)(7)(B) allows, in limited
fashion, for a stay of effectiveness of a rule during any proceeding
for reconsideration, but this authority presupposes the rule's
finalization, the rule's effectiveness, and the filing of an
administrative petition for reconsideration. Making the rule effective
also ensures the finality of the action ``for purposes of judicial
review.'' See CAA section 307(b). Nothing in our response here limits
or inhibits the filing of a petition for judicial review or the powers
of a reviewing court.
    Comment: EPA should update both its atmospheric modeling platforms
as part of the upcoming Appendix W rewrite and the cost manual in order
to support reasonable future assessments of visibility impacts and
appropriate control strategies consistent with the Committee Report
associated with the Consolidated Appropriations Act of 2014.
    Response: As a general matter, wherever possible, we intend to
follow the committee report instructions associated with the
Consolidated Appropriations Act of 2014, even where not specifically
incorporated by reference into the CAA itself. We are currently working
to update our ``Guideline on Air Quality Models'' in appendix W to part
51 of title 40, Code of Federal Regulations, and we proposed updates on
July 29, 2015. Also, as of the date of responding to this comment, we
have proposed updates to chapters within our Control Cost Manual.
    Comment: One commenter stated that if we change the final rule to
not include SO2 reductions at one of the affected
facilities, we must conduct an analysis under Executive Order 13045--
Protection of Children from Environmental Health Risks and Safety
Risks. Another commenter suggested that polluters need to reconsider a
business model that burdens low income communities, especially those
with minority populations, with the effects of air pollution, and urged
that EPA is accountable to low income, underserved, and vulnerable
communities in Texas that are constantly being ignored.
    Response: As explained more fully in a later section of this
document and in our RTC document, Executive Order 13045 does not apply.
To the extent our final rule limits emissions of SO2, this
will also increase the level of environmental protection and beneficial
effect on human health for all affected populations without having any
disproportionately high and adverse human health or environmental
effects on any population, including any minority or low-income
population.
    Comment: EPA has improperly avoided analyzing and evaluating
potential energy-related impacts of the proposed rule on reliability
and prices of electricity in Texas and the ERCOT region, despite
Executive Order 13211 requiring such evaluation. The EPA is using a
loophole in Executive Order 12866, despite meeting the cost and effect
criteria and the order's purpose, to avoid evaluating the potential
energy impacts of the proposed action as required by Executive Order
13211. Moreover, the proposed rule is inconsistent in claiming the rule
is both of national scope and effect and not of general applicability.
Additionally, CAA section 169A(g) requires that the state and the
Administrator consider the energy and non-air quality environmental
impacts of compliance when determining BART. Finally, citing ERCOT's
recent report, the proposed FIP affects a significant portion of Texas'
base load power generation fleet and the potential for adverse effects
from the EPA's proposed rule is actually increased, not lessened,
because the costs and impacts of the rule are focused within a smaller
region. Therefore, regardless of Executive Order 13211 applicability,
EPA should evaluate and consider the impacts of the proposed FIP on the
reliability and price of electricity in Texas.
    Response: As explained more fully in a later section of this
document and our RTC document, Executive Order 13211 does not apply as
this action is not a rule of general applicability under Executive
Order 12866. Our determination regarding this is not inconsistent with
our determination that the rule is of national scope and effect, as
these are different determinations that we fully evaluated under their
respective standards, and are not directly comparable. Additionally, we
did consider the commenter's concerns regarding grid reliability and
price of electricity, as discussed more fully in the Grid Reliability
section of this document, so we did not ``utilize a loophole'' in the
applicability provisions of Executive Order 12866 to

avoid consideration of the concerns raised in this comment.

I. Controls in Addition to CAIR/CSAPR, and CSAPR Better Than BART

    Comment: Texas is the only state included in CSAPR for which EPA is
issuing a FIP for reasonable progress. EPA proposed to issue a FIP that
would replace Texas' reliance on CAIR to satisfy the BART requirement
for EGUs with reliance on CSAPR. But EPA's proposal otherwise
disregarded CSAPR's more stringent SO2 and NOX
emission budgets for Texas, as compared to CAIR, as well as the
additional trading restrictions imposed by CSAPR. For all other states
that have relied on either CAIR or CSAPR, EPA found such participation
to satisfy the states' reasonable progress obligation for the first
planning period for those sources. EPA should not require controls
beyond BART for BART sources because it is reasonable to conclude that
no additional emissions controls are necessary for BART sources in the
first planning period.
    Response: As discussed elsewhere in this document, although we
proposed to rely on CSAPR to address the BART requirements for EGUs in
Texas, we are not finalizing that proposed action. On July 28, 2015,
the D.C. Circuit Court issued its decision in EME Homer City \87\
upholding CSAPR but remanding without vacating a number of the Rule's
state emissions budgets, including Texas' budgets. We are currently in
the process of determining the appropriate response to the remand, and
the extent to which the SO2 and NOX CSAPR budgets
for Texas will change is currently unknown. The uncertainties regarding
the CSAPR SO2 budgets are particularly relevant given our
rule's focus on this pollutant.\88\ Even assuming, however, that EME
Homer City had not invalidated the CSAPR NOX and
SO2 budgets for Texas and that we were taking final action
to address the BART requirements through reliance on CSAPR, we do not
agree that we are prohibited from requiring controls beyond CSAPR for
purposes of reasonable progress. We noted in 2005 that the
determination that CAIR provided for greater reasonable progress than
BART did not answer the question of whether more than CAIR would be
required in a regional haze SIP.\89\
---------------------------------------------------------------------------

    \87\ EME Homer City Generation v. EPA, 795 F.3d 118 (D.C. Cir.
2015).
    \88\ ``In short, EPA's 2014 SO2 emissions budgets for
Texas, Alabama, Georgia, and South Carolina require each of those
States to reduce emissions by more than the amount necessary to
achieve attainment in every downwind State to which it is linked.
The reductions on those four States are unnecessary to downwind
attainment anywhere. Those emissions budgets are therefore
invalid.'' EME Homer City, at 129 (citing EME Homer, 134 S. Ct.
1584, 1608-9 (2014)) (internal quotations omitted).
    \89\ 70 FR 39104, 39143.
---------------------------------------------------------------------------

    Furthermore, such a simplistic comparison ignores the meaningful
differences between Texas and the other states cited by commenters in
which no controls on NOX and SO2 from EGUs beyond
CSAPR were required. As explained in our proposed rulemaking, allowing
Texas to rely on CSAPR to meet its reasonable progress obligations is
not appropriate, considering the large impact of Texas sources on
visibility at Big Bend, the Guadalupe Mountains, and the Wichita
Mountains and the availability of cost-effective controls even after
considering CAIR/CSAPR's previously projected reductions.
    Comment: EPA should disapprove Texas' determination to exclude all
BART-eligible sources from being subject to BART and EPA should do
source by source BART for NOX. Further, if EPA does not
finalize the proposed controls for reasonable progress, then EPA should
do source by source BART for SO2. EPA's proposal to rely on
CSAPR as an alternative to BART is unlawful for three reasons. First,
EPA's proposal exempts sources from BART requirements without complying
with the statutory prerequisites for such an exemption. Second, even if
EPA could relieve the sources of the obligation to install BART
controls, the ``Better than BART'' rule upon which EPA relies is
flawed. Third, the ``Better than BART rule'' is no longer valid given
the substantial changes in CSAPR allocations and compliance deadlines.
    Response: As discussed above, we are not finalizing our proposed
action to rely on CSAPR to address BART due to the partial remand of
CSAPR in EME Homer City. We will address the question of appropriate
SO2 and NOX BART limits for EGUs in Texas in a
future rulemaking. Comments concerning the appropriateness of CSAPR as
an alternative for BART in Texas are not relevant to this action.
Additionally, we are finalizing the proposed controls for reasonable
progress. Therefore, the comment that we should do source-by-source
BART for SO2 if the reasonable progress controls are not
finalized is moot.

J. Installation of Controls Beyond the First Planning Period

    Several comments assert that our FIP authority is limited to
``filling the gaps'' in a state's SIP submission. These commenters
further contend that our FIP authority is limited by the scope of the
SIP submission. Because the required reasonable progress goals should
be met at the conclusion of the first planning period, the commenters'
argument continues, our FIP authority is likewise limited to those
controls that can be implemented by 2018. We disagree. Our authority to
use a FIP to address a ``gap'' or ``inadequacy'' in a SIP refers to a
``gap'' in the plan's coverage of requirements contained in the statute
and regulations, and is not limited to the specific ``gap'' left by the
disapproved portions of the scope of action covered in the state's SIP
submission, as commenters suggest.\90\
---------------------------------------------------------------------------

    \90\ See CAA Sections 110(c) and 303(y).
---------------------------------------------------------------------------

    In this action, we are determining whether Texas has addressed the
regional haze requirements set forth in the CAA and our implementing
regulations. Our FIP determines that under a proper assessment of
reasonable progress factors, additional controls for some sources in
Texas are warranted for the first planning period. Regulatory delays
created by a complex Texas submission and EPA actions regarding the
state's regional haze requirements, including the time needed for EPA
to assess the complex 2009 submission and the thousands of comments
received on our proposed action, cannot provide an exemption from the
CAA requirement to address regional haze. Nor can regulatory delays
make additional delays excusable when the requisite CAA analysis
concludes the controls are warranted at the earliest opportunity to
make reasonable progress. Additionally, there is nothing in the CAA or
the regional haze rules that constrains our FIP authority to only those
controls that can be installed in the first planning period. While
reasonable progress goals reflect that degree of visibility improvement
attainable during the first planning period (which extends to 2018), as
was indicated in our proposal, the long-term strategy requirements of
the program by their very nature look beyond these interim goals to the
state's ``long term'' approach to addressing regional haze and may
include control measures and accompanying visibility improvements that
extend beyond the first planning period.\91\ The commenter's concerns
center upon controls that are not accounted for in the numerical
reasonable progress goals, but rather as we acknowledge, are part of
the long-

term strategy and needed for reasonable progress.
---------------------------------------------------------------------------

    \91\ 79 FR 74874, citing Guidance for Setting Reasonable
Progress Goals Under the Regional Haze Program, Section 5.2. By
statute, the long-term strategy for making reasonable progress may
extend ``ten to fifteen years.'' CAA Section 169A(b)(2)(B); 42
U.S.C. 7491(b)(2)(B).
---------------------------------------------------------------------------

    Comments also asserted that our proposed FIP disregards the ``time
necessary for compliance'' factor of the reasonable progress analysis.
As we discuss in detail in the RTC document, we are required by
regulation to ``consider'' time necessary for compliance when
establishing reasonable progress goals, and we satisfied this
requirement by proposing reasonable progress goals that account only
for those controls that can be fully installed within the first
planning period, as is consistent with our Reasonable Progress
Guidance.\92\ For the scrubber retrofits that may require up to five
years to fully install, we exercised our authority to propose a long-
term strategy including emission limits that require controls that may
not be operational during the planning period and therefore are not
included in the reasonable progress goals. We also note that we expect
that design and construction of the scrubber retrofits will begin
within the planning period, in order to meet the five-year compliance
date. This approach is consistent with other FIPs issued by EPA and
takes into account the time engagement required to promulgate a FIP
within a planning period and the significance of the CAA's contemplated
ten to fifteen year long-term strategy.
---------------------------------------------------------------------------

    \92\ See our Reasonable Progress Guidance, page 5-2: ``It may be
appropriate for you to use this factor to adjust the RPG to reflect
the degree of improvement in visibility achievable within the period
of the first SIP if the time needed for full implementation of a
control measure (or measures) will extend beyond 2018.''
---------------------------------------------------------------------------

    Other comments asserted that our requirement for controls outside
of the planning period is inconsistent with previous FIPs. We disagree
with this comment. First, we have proposed or promulgated FIPs
requiring controls with compliance dates beyond the first planning
period, including FIPs for Arkansas and Wyoming. The Oklahoma FIP
includes requirements beyond the first planning period as the result of
a stay during litigation. Further, we have applied the requirements of
the regional haze program to ensure consistency in the requirements
upon the sources subject to regulation. If we were to follow the
commenters' arguments and fail to require application of necessary
controls on Texas sources past the first planning period, those sources
would be treated inconsistently with sources in other states that were
required to apply the controls necessary to meet the CAA's requirement
to address regional haze. We cannot agree to inconsistent application
of necessary controls at Texas sources due to delays in promulgating a
FIP or time-intensive installation schedules, but rather, we address
these program requirements through the long-term strategy, which, as
discussed above, allows for control strategies that can begin design
and construction but cannot be completed within the planning period.
    Several comments assert that our regulatory delays preclude EPA
from imposing certain emission limitations that may not be achieved
within the first planning period. Despite any delays in finalizing our
action on the Texas SIP or in promulgating the FIP, we have a duty to
act on the SIP and a duty to fulfill the regional haze requirements of
the Act, including the authority to promulgate a FIP that imposes the
controls required by the CAA where a SIP submission fails to do so.
This duty and authority is not forfeited or constrained by delays,
whatever their cause. We likewise disagree with commenters who consider
it inappropriate for controls to be required after the planning period
because corresponding visibility benefits may not be realized during
the planning period. The fact that benefits of such controls may not be
realized within the first planning period does not affect our
determination that the controls are necessary nor deprive us of our
authority to impose the requirements.
    A commenter asserted that all of the controls required under the
proposed FIP can be installed within the first planning period. We
agree that in some cases scrubber retrofits can and have been installed
in less than five years; however, we do not have the information
necessary to make that determination for each specific facility
included under the proposed FIP. Thus, we proposed an installation
timeframe consistent with past successful BART-related scrubber
retrofits that, while conservative, ensures the necessary time to
install the controls.

K. Cost

    We received numerous comments related to the cost analyses we
performed to support the seven scrubber retrofits and the seven
scrubber upgrades we proposed. These comments were received from both
industry and environmental groups, and covered all aspects of our cost
analyses.
    Some of the comments we received from industry concerning our
proposed scrubber retrofits were objections to our use of the IPM cost
algorithms that were developed by Sargent and Lundy (S&L) under
contract to us. As we discuss in our Cost TSD, we programmed the DSI,
SDA, and wet FGD cost. algorithms, as employed in version 5.13 of our
IPM model, into spreadsheets.\93\ Industry stated these cost algorithms
were not accurate enough to warrant their use in individual unit-by-
unit cost analyses and that our use of them violated our Control Cost
Manual. Others stated the IPM cost algorithms do not consider site-
specific costs, or in the case of wet FGD, do not adequately consider
wastewater treatment.
---------------------------------------------------------------------------

    \93\ See discussion beginning on page 3 of our Cost TSD for more
information concerning our use of the IPM cost algorithms.
---------------------------------------------------------------------------

    In summary, we disagree with these commenters and conclude that the
IPM cost algorithms provide reliable, study-level, unit-specific costs
for regulatory cost analysis such as required for BACT, BART, and
reasonable progress.\94\ We received other comments relating to our
scrubber retrofit cost analyses, but none of them caused us to revise
our scrubber retrofit cost-effectiveness basis. We also received a
number of comments that our proposed emission limits were too
stringent. We disagree with these comments and present several lines of
evidence, including real-world data demonstrating that our proposed
emission limits are not only achievable, but are in fact conservative
in many cases.
---------------------------------------------------------------------------

    \94\ We believe that the IPM cost algorithms provide study level
accuracy. See pdf page 17 of our Control Cost Manual: ``[a]``study''
level estimate [has] a nominal accuracy of  30% percent.
According to Perry's Chemical Engineer's Handbook, a study estimate
is `. . . used to estimate the economic feasibility of a project
before expending significant funds for piloting, marketing, land
surveys, and acquisition . . . [However] it can be prepared at
relatively low cost with minimum data.' ''
---------------------------------------------------------------------------

    As we discuss in our proposal,\95\ our scrubber upgrade analyses
were based on information we received in response to our requests under
CAA section 114(c). This information was claimed as CBI under 40 CFR
2.203(b). As a consequence, we are obligated to protect the
confidentiality of that information while it is subject to such claims,
which precludes us from publicly posting this in our docket at
regulations.gov. CBI information, while a part of our rulemaking
docket, is protected from public disclosure under our CBI requirements.
Although we received some public domain comments on our proposed
scrubber upgrades, most were claimed as CBI. We analyzed that
information, and as we discuss below in our comment response summary,
we have modified certain aspects of our analyses. Like our proposed
scrubber upgrade cost analyses, our revised scrubber upgrade cost
analyses are similarly treated as CBI but are available

for review by the respective facilities. This prevents us from being
able to publicly disclose the details of our analyses. Our revised
scrubber upgrade analyses changed our proposed cost-effectiveness basis
from where all scrubber upgrades were less than $600/ton, to where all
scrubber upgrades ranged from between $368/ton to $910/ton. This is
well within a range that we believe is cost-effective, given the
visibility benefits that will result from the installation of those
controls.
---------------------------------------------------------------------------

    \95\ See discussion beginning on 79 FR 74876, and section 4.5 of
our FIP TSD.
---------------------------------------------------------------------------

    Below we present a summary of our responses to the more significant
comments we received that relate to our proposed cost analyses.
    Comment: We received information from Luminant and NRG claimed as
CBI concerning our proposed scrubber upgrades. These companies hired
S&L who alleged that we made various errors in our cost analyses and
that our proposed SO2 emission rates were too low. In
related comments, Luminant stated that it hired S&L to review our
scrubber upgrade cost analyses and, in so doing, it found multiple
flaws. S&L states that many of our assumptions are not valid,
especially those regarding the accuracy and scope of the CBI estimates
we relied upon, our calculation of SO2 baseline emissions,
achievable efficiency, and our calculations of the operating costs. We
also received comments from the TCEQ that we should have provided more
detail about how we developed the costs for these scrubber upgrades.
Earthjustice \96\ submitted information concerning previous scrubber
upgrades that supports the reasonableness of our assumed control level
of 95%.
---------------------------------------------------------------------------

    \96\ When we refer to Earthjustice, we also mean the National
Parks Conservation Association and the Sierra Club as these groups
collectively submitted comments. These groups also contracted with
independent technical experts including Ms. Victoria Stamper, Dr. H.
Andrew Gray, and Dr. George D. Thurston.
---------------------------------------------------------------------------

    Response: As explained above, because Luminant and NRG claimed the
above information as CBI, we were required to separate out such CBI and
respond to it in a separate CBI protected document (organized by
claimants). Although this information is a part of our record to this
action, we cannot post it to our electronically posted public docket at
www.regulations.gov. We disagree with the TCEQ that we should have
provided more information concerning the cost of the scrubber upgrades
we analyzed. Our scrubber upgrade cost information was based on
information supplied under CBI claims by the affected facilities in
response to requests for information under CAA section 114(a).
Accordingly, although this information is still in our docket, and is
being used to support our decision making, it cannot be included in our
publicly posted docket at www.regulations.gov and can only be disclosed
by us to the extent permitted by CAA section 114(c) and our regulations
governing treatment of CBI as set out at 40 CFR part 2, subpart B.
    We generally disagree that our analysis was flawed. We specifically
used information provided by Luminant's and NRG's own independent
contractors (e.g. S&L) whom they hired to assist in providing
information responsive to our CAA section 114 requests. We have
reviewed the scrubber upgrade cost analyses performed by S&L that were
provided with separate comments from NRG and Luminant and adopted S&L's
methodology, which mainly concerned operational costs. However, we
noted many errors and undocumented cost figures in S&L's analyses. We
corrected these errors and rejected some of S&L's undocumented
assertions and/or costs. Nevertheless, in order to produce a
conservative scrubber upgrade cost analysis and set many of the issues
that Luminant raises aside, we incorporated many of Luminant's cost
items. The resulting costs for Luminant's scrubber upgrades increased
slightly, resulting in a range of $368/ton to $910/ton for all of the
scrubber upgrades, but remained well within a range that we believe is
cost-effective, given the visibility benefits that will result from the
installation of those controls.
    Comment: San Miguel stated that it should not be included in our
FIP, but if it was included, its SO2 emission limit should
be increased and its emission averaging period should be changed from a
monthly basis to an annual basis.
    Response: We have reanalyzed the monthly emission data for San
Miguel, including calculating the 30 BOD average for it since it
completed its scrubber upgrades. We reaffirm our proposed conclusion
that based on the coal that San Miguel has historically burned over the
last several years, and its demonstrated ability to remove 94% of the
sulfur from that coal, that it should be able to meet our proposed
emission limit of 0.60 lbs/MMBtu based on a 30 BOD average. We also
believe additional spare capacity exists in San Miguel's scrubber
system. However, similar to what we discussed in our proposal,\97\ and
in section I.B.3.b, of this action, we offer San Miguel the opportunity
to install a Continuous Emissions Monitoring System (CEMS) at its
scrubber inlet and demonstrate that it maintain at least 94% control
based on a 30 BOD average. Our RTC document has more details on these
options.
---------------------------------------------------------------------------

    \97\ See discussion beginning on 79 FR 74885.
---------------------------------------------------------------------------

    Comment: The TCEQ summarized its approach to analyzing controls for
reasonable progress and stated that its approach was adequate. In
particular, the TCEQ defended its use of a $2,700/ton threshold for
control, which it stated was used in CAIR, and its decision that the
cost of the controls was not worth the improvement in visibility.
    Response: As we note in our proposal,\98\ we disagree with the TCEQ
that its approach to reasonable progress was adequate. We note that to
the extent that TCEQ's cost threshold was reasonable, our estimate of
the costs of the controls required by our FIP fall below the $2,700/ton
threshold used by Texas, with one exception. For the one source with
estimated costs exceeding $2,700/ton, the costs of controls is less
than the $2,700 threshold selected by Texas, after adjusting for the
escalation of costs over time.\99\ The TCEQ's potential control set
consisted of a mix of large and small sources, located at various
distances from Class I areas, with a large geographical distribution.
Some controls would likely result in significant visibility benefits,
but some would result in little to almost no visibility benefits.
Because it only estimated the visibility benefit of all the controls
together and weighed those benefits against the total cost of
controlling the mix of sources under consideration, the TCEQ was not
able to assess the benefit of controlling individual sources or the
subset of sources with significant, and potentially cost-effective,
visibility benefits. Larger individual benefits were obscured by the
inclusion of those controls with little visibility benefit that only
served to increase the total cost figures. As a result, despite its own
conclusions that controls below $2,700/ton were available for a number
of sources,\100\ and CENRAP's modeling results that Texas point sources
impact the visibility at the Wichita Mountains several times more than
the impacts from Oklahoma's own point sources, Texas ultimately decided
to not control these sources.

Furthermore, Texas' analysis did not include consideration of scrubber
upgrades on key sources with large visibility impacts and potentially
very cost-effective controls. Texas' flawed analysis prevented it from
properly considering whether reasonable controls were available on the
subset of sources or group of sources with the largest visibility
impacts. Although our Regional Haze Rule and our Reasonable Progress
Guidance provide states with latitude in approaching reasonable
progress, states must still meet the requirements of the CAA and
Federal requirements. We conclude that Texas' approach was flawed and
this fundamental critical flaw in Texas' analyses cannot be approved.
---------------------------------------------------------------------------

    \98\ 79 FR 74838.
    \99\ Conservatively escalating the $2,700/ton value from when it
was first developed for the CAIR rule, which was finalized on March
10, 2005, to the time of our analysis, which was conducted in 2014,
results in a value of $3,322/ton (i.e., the Chemical Engineering
Plant Cost Index for 2005 = 468.2, and that for 2014 = 576.1; $2,700
x 576.1/468.2 = $3,322).
    \100\ See Appendix 10-1 of the Texas Regional Haze SIP. For
example, the costs of scrubbers for Big Brown (Acct No F10020W)
Units 1 and 2 were determined to be $1,573 and $1,540, respectively.
---------------------------------------------------------------------------

    Comment: Earthjustice agreed with our conclusion that Texas'
approach to reasonable progress obscured potentially cost-effective
controls. Earthjustice also generally supported our reasonable
progress/long-term strategy analysis, concluded that in comparison with
other actions our costs were conservative (high) but reasonable, but
stated that additional units should have been proposed for control.
Earthjustice criticized our emission baseline methodology of
eliminating the high and low values from the 2009-2013 emission data
and averaging the resulting three years of data. It reanalyzed our
scrubber retrofit cost-effectiveness calculations for Big Brown,
Monticello, Coleto Creek, Welsh Units, W. A. Parish, and Tolk Units 1
and 2, using a straight 5-year average of the 2009-2013 emissions, and
concluded our costs were too high. Earthjustice generally stated our
assumed DSI SO2 removal efficiency was too high.
Earthjustice believed we should have considered coal blending with low
sulfur coal and lignite drying. Earthjustice also provided an analysis
for Novel Integrated Desulfurization (NID). Earthjustice concluded that
our calculated cost-effectiveness values were too high, and that NID
was also a viable alternative to SDA and wet FGD and offered some
advantages.
    Response: We confirm that one of our intentions in performing our
cost analyses was to conservatively estimate many of the individual
cost parameters (tending toward a higher cost estimate) and demonstrate
that even doing this, our proposed scrubber upgrade and scrubber
retrofit cost analyses were cost-effective. We believe we have met that
goal. We disagree with Earthjustice that we should have proposed
additional units for control and respond to this comment in the
Modeling section of this document and the RTC document. We continue to
believe our five-year emission baseline methodology, with the
elimination of the highest and lowest emission years, is appropriate.
The BART Guidelines, which we drew upon for some of our reasonable
progress/long-term strategy analyses, state that the emission baseline,
``should represent a realistic depiction of anticipated annual
emissions for the source. In general, for the existing sources subject
to BART, you will estimate the anticipated annual emissions based upon
actual emissions from a baseline period.''[hairsp]\101\ We eliminated
the high low values from the 2009-2013 emission to better address
issues such as variations in coal sulfur content, capacity usage,
operations, etc., and make the baseline more representative of typical,
recent plant operations. The difference between our baseline
calculations and a straight 2009-2013 average is small and would not
change our conclusion that the scrubber upgrades we proposed are very
cost-effective. We also believe our DSI analysis strategy was
appropriate. We analyzed DSI at both a 50% control level that is likely
achievable for all the units, and the highest level of control the
units were potentially capable of achieving, with design factors and
costs adjusted accordingly, thus bracketing the problem.
---------------------------------------------------------------------------

    \101\ 70 FR 39167.
---------------------------------------------------------------------------

    We do not believe there is enough information concerning NID
installations at this time to warrant an intensive analysis of that
technology. Given the vendor advertised control efficiency of NID, the
selection of NID technology rather than wet FGD would not change our
proposed SO2 limits. With the exception of Tolk, the non-air
quality environmental impacts of a NID and wet FGD are similar and do
not warrant eliminating either technology. We proposed that the units
in question meet certain SO2 emission limits, but we did not
mandate a specific control technology in doing so. Consequently, any
unit, including the ones discussed herein, may elect to use a NID to
achieve our required SO2 emission limits.
    With respect to the comment that we should have considered blending
the coal used at the units with low sulfur coal, we note that most of
the units in question either burn lower sulfur Powder River Basin (PRB)
coal or they blend it with lignite. We do not believe we have the
necessary technical information (e.g., fuel sulfur content,
availability, cost, contractual information, etc.) to properly consider
fuel blending or fuel switching. Nevertheless, the emission reductions
achieved by switching to cleaner coal are much less than the emission
reductions anticipated due to the implementation of the required
controls. We agree that in some circumstances coal drying can be a
viable technology for improving boiler efficiency and, in the process,
reduce emissions because less coal is burned to achieve the same heat
input to the boiler. However, we are not required to consider every
potential technology under the reasonable progress and long-term
strategy provisions of the Regional Haze Rule, which applies to the
analysis in question. We considered both SDA and wet FGD, and the next
most promising SO2 removal control, DSI. Were we to have
considered coal drying, it would have ranked below DSI in its ability
to remove SO2.
    Comment: Luminant provided general objections to our cost analyses
and stated our analysis relies entirely on a cost-per-ton metric but
ignores what it considers the more meaningful cost-per-deciview metric.
    Response: Luminant's general cost comments are addressed with
specificity in the cost section of our RTC document. We reject
Luminant's contention that we should have used the $/dv metric, a
contention we also rejected and addressed in our Oklahoma FIP.\102\ We
note that to use the $/dv metric as the main determining factor would
most likely require the development of thresholds of acceptable costs
per deciview of improvement for both single and multiple Class I
analyses. In Oklahoma v. EPA, the Tenth Circuit Court recognized our
authority to use a different metric when promulgating a FIP.\103\
---------------------------------------------------------------------------

    \102\ Response to Technical Comments for Sections E. through H.
of the Federal Register Notice for the Oklahoma Regional Haze and
Visibility Transport Federal Implementation Plan, Docket No. EPA-
R06-OAR-2010-0190, 12/13/2011, pdf 116.
    \103\ ``When promulgating its own implementation plan, [EPA] did
not need to use the same metric as Oklahoma. The guidelines merely
permit the BART-determining authority to use dollar per deciview as
an optional method of evaluating cost effectiveness.'' Oklahoma v.
EPA, 723 F.3d 1201, 1221 (10th Cir. 2013).
---------------------------------------------------------------------------

    Comment: S&L cited to capital costs at Monticello 3 and Sandow 4,
including spray headers and mist eliminators, that we mistakenly
removed from our scrubber upgrade cost analyses.
    Response: S&L is correct that we did in fact remove these capital
costs from our scrubber upgrade cost analyses because we noted these
costs were included in a 2013 Use Determination Application to the
TCEQ, which identified that new replacement tower spray nozzles and
mist eliminators had been installed. We wrongly assumed

that after having identified that its scrubber system could be upgraded
cost-effectively, and having performed some of those modifications,
Luminant had installed new upgraded spray headers and nozzles rather
than replacing its worn out spray header and nozzles with the less
efficient original design. However, based on the comment received on
this, we added these costs back into our updated scrubber upgrade cost
analyses and the result was a very minor increase in the cost-
effectiveness value (higher $/ton). This did not affect our conclusion
that upgrading the scrubbers for these units is very cost-effective.
    Comment: S&L states that in escalating costs, we should have
assumed its 2006 reports were in 2005 dollars and we should have
escalated our costs out to 2015. S&L also objected to our use of a 10%
increase to our escalation to account for escalation outside of the
customary five-year window, our deletion of Allowance for Funds During
Construction (AFUDC), and our deletion of owner's costs. S&L, GLCC, and
CCP allege our use of a 30-year life for our scrubber retrofit and
scrubber upgrades analyses is inconsistent with our Control Cost
Manual. Earthjustice supported our 30-year assumed life.
    Response: We agree with S&L that we should have assumed its 2006
reports were in 2005 dollars, and we have made the appropriate
correction to our escalation calculations. We disagree that we should
have carried our escalation costs forward to 2015, because we used the
most recent emission data that was available, for both the cost
analyses and modeling, which was 2013 data. As we explain in more
detail in the Cost section of the RTC document, based on consideration
of the CEPCI cost indices over the 2005-2013 period, we conclude that
our approach of adding an additional 10% to our escalated cost is
reasonable and likely conservative. As we have noted in a number of
previous actions, AFUDC and owner's costs are not allowable under the
Control Cost Manual overnight approach.\104\ We refer S&L to our
response to the scrubber life issue in our Oklahoma FIP in which we
supported a 30-year life.\105\ Because none of the facilities involved
have entered into (or offered to enter into) enforceable commitments to
shut down the applicable units earlier, we have continued to use a 30-
year equipment life for scrubber upgrades, as we believe that is
proper.
---------------------------------------------------------------------------

    \104\ See for instance our ``Response to Technical Comments for
Sections E. through H. of the Federal Register Notice for the
Oklahoma RH and Visibility Transport Federal Implementation Plan,''
Docket No. EPA-R06-OAR-2010-0190, 12/13/2011.
    \105\ Response to Technical Comments for Sections E. through H.
of the Federal Register Notice for the Oklahoma RH and Visibility
Transport Federal Implementation Plan, Docket No. EPA-R06-OAR-2010-
0190, 12/13/2011. See discussion beginning on page 36.
---------------------------------------------------------------------------

    Comment: Xcel notes that in performing our dry scrubber cost
analysis for Tolk, we failed to consider that there is a general water
scarcity in the area with no surface water availability, and that to
obtain the additional amount of water necessary to support the
operation of dry scrubbers, Xcel would have to attempt to purchase
water rights from existing farmers along with a gathering system or
look at other costly alternatives. Based on the historical cost of
water rights in the area, this is an additional capital cost of
approximately $40 million that was not included in EPA's cost
estimates. Earthjustice encouraged us to investigate Xcel's water
rights, and estimated the cost to purchase additional water rights
based on assumptions we used to assess this issue for the Gerald
Gentleman facility in Nebraska.
    Response: We have conducted an extensive investigation of the issue
raised in Xcel's comments, including additional communication with Xcel
and the High Plains Water District, in order to clarify some of Xcel's
assertions.\106\ We conclude that Xcel's asserted water requirements
for dry scrubbing are much higher than other similar dry scrubbing
installations, and the basis for the disparity is unsupported. As
confirmed by our communications with the High Plains Water District and
Xcel, we also conclude that Xcel has multiple lines of access to
adequate supplies of water sufficient to supply the proposed dry
scrubbers (SDA) without the need to buy additional water rights. First,
we calculate that water already available at Tolk is almost enough to
satisfy the additional water demand of our proposed dry scrubbers.
Second, we note that Xcel receives blowdown water from nearby Plant X
\107\ and that Xcel offered testimony to the Public Utility Commission
of Texas that two units in Plant X will retire in 2019 and 2020, which
will free up additional water that could be used to satisfy the
additional water demand of our proposed dry scrubbers. Third, we
believe that Xcel has access to additional unexploited water rights
that are more than adequate to supply our proposed dry scrubbers.
Lastly, we acknowledge that Tolk's ultimate sources of water, the
Ogallala Aquifer, continues to be depleted. However, considering the
water needed by our proposed dry scrubbers is by Xcel's own account
only approximately 9 to 12% of the total plant's needs, the aquifer's
depletion will be a limiting factor on the operation of the plant
itself, not on the operation of the scrubbers.
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    \106\ Please see our docket for inclusion of this communication,
which are in the form of emails transmitting letters and other
information.
    \107\ ``Plant X'' is the actual name of a nearby EGU also owned
by Xcel.
---------------------------------------------------------------------------

    Comment: Xcel alleged that in our cost analysis we failed to
consider that our proposed dry scrubbers would (1) end Tolk's sales of
its fly ash or require the installation of additional baghouse
capacity, and (2) require additional landfill capacity. Xcel also
alleged that we did not adequately consider DSI and non-air
environmental impacts, and that our assumption of a 30-year operating
life is wrong.
    Response: We disagree with these comments. Our cost analysis did
include an additional baghouse that could be installed upstream of the
dry scrubber which can preserve Tolk's existing fly ash sales. Also,
our cost analysis included landfill costs, which based on Xcel's own
information, are adequate to cover the additional disposal costs. We
also believe our DSI cost methodology, in which we bounded the range of
expected DSI performance, was adequate and demonstrated that DSI was
not cost-effective when compared to the dry scrubber we costed for
Tolk. Lastly, as we discuss in our responses to other comments, we
believe our assumption of a 30-year life is proper, and we note that in
testimony to the Public Utility Commission of Texas (PUCT), Tolk
assumed similar equipment lives.
    Comment: S&L states we overestimated SO2 reductions (and
thus our cost-effectiveness calculation was too low) for scrubber
upgrades due to our SO2 baseline methodology in which we
eliminated the high and low annual average values from 2009-2013 and
averaged the remaining three yearly values. Earthjustice stated we
overestimated our cost-effectiveness calculations for our scrubber
retrofits in part due to our SO2 baseline methodology.
Earthjustice stated it would have been more appropriate to use a five-
year annual average emissions baseline, five-year annual average
SO2 rate in lb/MMBtu, and five-year average gross heat rate
and MW-hrs generated, based on data from 2009 to 2013.
    Response: We disagree with the commenters. As we note in our
proposal, we used the BART Guidelines for some aspects of our analysis
and believe our methodology is in agreement

with the relevant language in that regard.\108\ We calculated our
baseline SO2 emissions by first acquiring the 2009 to 2013
emissions as reported to us by the facilities in question. This is
reflective of the actual emissions from the underperforming scrubber
systems installed at the units in question. We then calculated the
uncontrolled SO2 emissions by acquiring U.S. Energy
Information Agency coal usage data. We used these two figures to
calculate the level of control for each year. In so doing, we
eliminated the highest and lowest annual emission values from 2009-2013
to better address the issues S&L raises in its other comments
(variations in coal sulfur content, capacity usage, operations, etc.)
and to make the baseline more representative of typical, recent plant
operations. The difference between our baseline calculations and a
straight 2009-2013 average is small and does not change our proposed
conclusion that the scrubber upgrades we proposed are very cost-
effective.
---------------------------------------------------------------------------

    \108\ 70 FR 39167. ``The baseline emissions rate should
represent a realistic depiction of anticipated annual emissions for
the source.'' See also 79 FR 74874.
---------------------------------------------------------------------------

    Comment: S&L stated that our assumption that wet FGD retrofits can
achieve 98% reduction or a controlled SO2 emission rate of
0.04 lb/MMBtu is unrealistic and cannot be sustained on a continuous,
long-term basis. Earthjustice stated that our assumed scrubber retrofit
emission rates were not stringent enough.
    Response: We disagree with S&L. First, we note that vendors
routinely guarantee SO2 emission limits at least as
stringent as, or more stringent than, what we have proposed. We have
also conducted extensive analysis of a number of SO2
scrubber retrofits in which we have plotted their 30 BOD SO2
emission limits.\109\ Of the units we analyzed, 13 retrofit units have
guaranteed control efficiencies of 95% to 99%, with eight of them
guaranteed at 98% to 99%. With one exception, these eight units are
achieving 98% to 99% SO2 control, when calculated using a
very conservative method we have adopted. We also demonstrate that
units similar to the ones in question are able to continuously sustain
SO2 limits lower than what we have proposed for at least one
year, and in some cases much longer. For instance, three of the units
have achieved a maximum 30-day BOD equal to or less than our proposed
SO2 emission limit for scrubber retrofits of 0.04 lb/MMBtu:

    \109\ See our RTC document for much more detail on our analysis,
and the file, ``Selected scrubber retrofit efficiencies.xlsx,''
which is in our docket and contains the plots discussed. The
performance of each scrubber in our data set is summarized in the
file, ``Selected scrubber retrofit efficiencies.xlsx.''
---------------------------------------------------------------------------

 Scherer Unit 2: 0.01 lb/MMBtu based on 485 data points \110\
---------------------------------------------------------------------------

    \110\ Where ``data point'' represents a valid daily
SO2 monitored value.
---------------------------------------------------------------------------

 Iatan Unit 1: 0.02 lb/MMBtu based on 2,004 data points
 Boswell Energy Center: 0.03 lb/MMBtu based on 1,881 data
points

Our technical conclusions are also consistent with past judicial
findings regarding achievable removal efficiencies and control rates,
including conclusions in the already five years past case of United
States v. Cinergy Corp., 618 F. Supp. 2d 942, 947 and 961-962 (S.D.
Ind. 2009).\111\ Thus, we disagree with S&L that our proposed scrubber
retrofit SO2 emission limits are not realistic or
maintainable on a long-term basis. We agree with Earthjustice that it
may be possible that many of the scrubber retrofit units can achieve
greater control efficiencies than we proposed. Greater control
efficiencies would result in a more favorable cost-effectiveness (lower
$/ton) and more visibility improvement. This is another area in which
we strove to be conservative in our analyses in order to demonstrate
that even with many conservative cost assumptions the scrubber
retrofits we proposed are cost-effective.
---------------------------------------------------------------------------

    \111\ While the underlying expert report submitted by the
Department of Justice in that case is protected from release under
Court order, the testimony of the government expert witness that
substantially accords with it, as well as our conclusions in
responding to this comment, has been added to our docket.
---------------------------------------------------------------------------

    Comment: S&L stated that our use of the IPM cost algorithms was not
in keeping with our Control Cost Manual and because of the limited
number of site-specific inputs, the IPM cost algorithms provide order-
of-magnitude control system cost estimates, but do not provide case-by-
case project-specific cost estimates meeting the requirements of the
BART Guidelines, nor do the IPM equations incorporate the cost
estimating methodology described in the Control Cost Manual.
    Response: We disagree with S&L. As we stated in our Cost TSD, we
relied on the methods and principles contained within the Control Cost
Manual, namely the use of the overnight costing method. In fact, the
Control Cost Manual does not include any method for estimating the
costs of any of the SO2 control methods evaluated in this
action. We note our strategy of relying on a publicly available control
cost tool is similar to the strategy the states themselves employed in
the development of their own SIPs. For instance, as explained in the
Texas SIP, the TCEQ used the control strategy analysis completed by the
CENRAP, which depended on the EPA AirControlNET tool \112\ to develop
cost per ton estimates. We have used IPM cost models to estimate BART
costs in other similar rulemakings including our Arizona regional haze
FIPs,\113\ the Wyoming regional haze FIP,\114\ and to supplement our
analysis in the Oklahoma FIP.\115\ S&L used real world cost data to
construct its cost algorithms and confirm their validity. These cost
models have been updated and maintained since their introduction in
2010 and have been continuously used by us since that time. These
control costs are based on databases of actual control project costs
and account for project specifics such as unit size, coal type, gross
heat rate, and retrofit factor, and they require unit specific inputs
such as reagent cost, waste disposal cost, auxiliary power cost, labor
cost, gross load, and emission information. We believe that the IPM
cost models provide reliable study-level, unit-specific costs for
regulatory cost analysis such as required for BACT, BART, and
reasonable progress. Lastly, we are confident in the basic methodology
behind the S&L cost algorithms such that in our recent proposal for
updating the SCR chapter of the Control Cost Manual,\116\ we presented
an example costing methodology that is based on the IPM S&L SCR
algorithms, which were developed using a similar methodology to the wet
FGD, SDA, and DSI cost algorithms discussed herein.
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    \112\ Our AirControlNET tool is out of date and no longer
supported.
    \113\ 77 FR 42852 (July 20, 2012).
    \114\ Memorandum from Jim Staudt to Doug Grano, EPA, ``Review of
Estimated Compliance Costs for Wyoming Electricity Generating Units
(EGUs)--revision of previous memo'', February 7, 2013, EPA-R08-OAR-
2012-0026-0086.
    \115\ 76 FR 81728 (December 28, 2011).
    \116\ 80 FR 33515.
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    Comment: S&L stated that the IPM cost algorithms do not adequately
consider site specific information and it cites to a number of
possibilities including demolition and relocation of equipment,
modifications that may be required to the existing ash handling
systems, replacement of the existing induced draft fans or booster fan
modifications, modifications/upgrades to the existing auxiliary power
system, and labor productivity. S&L criticized our use of a retrofit
factor of 1.0 for all units, and stated that the inlet temperature of
Big Brown and Monticello units was 360-370 F, which

is above the 300 F assumed value in the IPM algorithms, and would
result in a flue gas volume increase of 10%, requiring additional
costs.
    Response: We note that the IPM cost algorithms, which are derived
from real world costs, already have retrofit issues built into them.
Our assumption of a retrofit factor of 1.0, which represents an average
retrofit difficulty, likely overestimates the costs of some facilities
(e.g., Tolk) that have no retrofit issues. We solicited comments on all
aspects of our scrubber retrofit cost analyses, but received little of
the site-specific information to which S&L cites. Also, S&L provides no
documentation for those it does cite. Regardless, these types of issues
result in small increases in costs that are well within the required +/
-30% accuracy \117\ and do not affect cost-effectiveness conclusions
due to the conservative nature of our estimates, as demonstrated
elsewhere in these responses.
---------------------------------------------------------------------------

    \117\ Control Cost Manual, p. 2-3.
---------------------------------------------------------------------------

    S&L does not provide any documentation to support its contention
that the IPM wet FGD cost algorithms are based on a generic scrubber
inlet temperature of 300 F. We have researched all available references
on this issue and cannot find anything to support this conclusion.
Rather, we conclude that the IPM cost algorithms estimate costs from
regression equations based on actual completed projects. There are a
number of factors other than temperature that affect the volume of gas
flow that passes through a scrubber system. These include the amount of
in-leakage in the system (which often increases due to inefficient or
worn seals in the air preheater) and the type and characteristics of
the coal that is being burned. This is made clear by examination of two
of the scrubber retrofit reports for Big Brown (one of the units S&L
cites), which were issued by S&L in 2004 and 2007, we received in
response to our CAA Section 114 requests.\118\ The 2004 report
indicated that the design flue gas flow rate at the scrubber inlet was
approximately 19.7% less than that in the 2007 report. However, both
reports indicated that the reference temperature at the inlet was 370
[deg]F--the same temperature S&L references in its comment--and both
were at the same pressure. It is clear there are many variables that
impact flow beyond temperature. We therefore conclude that S&L has not
documented its temperature assertion, available information does not
support it, and its temperature inference is too simple to properly
characterize the situation. In any case, even assuming a 10% increase
in gas flow rate, would not result in a significant enough increase in
cost to impact our decision regarding these facilities.
---------------------------------------------------------------------------

    \118\ LUMINANT_000277496.pdf and LUMINANT_REGHAZ_1-000001183 to
-000001257.pdf.
---------------------------------------------------------------------------

    Comment: S&L states the IPM cost module includes costs only for
minor physical and chemical wastewater treatment. However, wastewater
treatment standards proposed by EPA, and anticipated to be published as
a final rule in 2015, will likely require significantly more advanced
treatment of FGD wastewaters. S&L states this could add $30-$40 million
to the cost of a retrofit wet FGD control system and we should have
included these costs in our estimates.
    Response: Because our wastewater treatment rules have not been
finalized, and therefore we do not know with certainty whether any
additional costs may be incurred, it is not appropriate for us to
include those costs in our cost-effectiveness calculations. Even if
those costs prove to be substantial, other options are available,
including zero liquid discharge systems and the selection of a
SO2 control technology that achieves the emission limit
without generating a wastewater stream, such as NID scrubbers, which we
believe are capable of achieving our emission limits, and have been
selected in some recent installations.\119\ In addition, we believe
that at least one of the studies that produced actual costs that were
used to construct the IPM cost algorithms included wastewater treatment
costs. Lastly, we did not receive any documentation from any facility
to substantiate any wastewater treatment costs, including the figures
that S&L cites.
---------------------------------------------------------------------------

    \119\ We recently proposed approval of NID as BART for the Flint
Creek Unit 1 in Arkansas (80 FR 18944). Other recent installations
include the Homer City Units 1 and 2, Boswell Unit 4, Brayton Point
Unit 3, and Indian River Unit 4.
---------------------------------------------------------------------------

    Comment: Luminant and others allege we did not properly balance
costs and visibility benefit and stated we should have used the dollar
per deciview ($/dv) metric.
    Response: We disagree that the $/dv metric is more meaningful than
our use of the $/ton metric in conjunction with our consideration of
the visibility benefit from the installation of controls. As we noted
in our Oklahoma FIP,\120\ use of the $/dv metric would most likely
require the development of thresholds of acceptable costs per deciview
of improvement for BART determinations for both single and multiple
Class I analyses, and we have not developed such thresholds. This
decision by EPA not to use this metric in a FIP was reviewed and upheld
in Oklahoma v. EPA by the Tenth Circuit Court.\121\ We see no reason to
deviate from our view of the dollar per deciview metric in the
reasonable progress context that applies here. We also note that the
use of the dollar per deciview metric is further complicated in the
present case due to our use of CAMx modeling. As we discuss in our
proposal and elsewhere in the Modeling section of this document and in
Modeling Sections of our RTC document, there is no way to directly
compare the CAMx modeling we used in our proposed Texas/Oklahoma FIPs
with previous CALPUFF modeling results because of differences in the
models, model inputs, and metrics used.\122\
---------------------------------------------------------------------------

    \120\ Response to Technical Comments for Sections E. through H.
of the Federal Register Notice for the Oklahoma Regional Haze and
Visibility Transport Federal Implementation Plan, Docket No. EPA-
R06-OAR-2010-0190, 12/13/2011, pdf 116.
    \121\ Oklahoma v. EPA, 723 F.3d 1201, 1221 (10th Cir. 2013).
    \122\ See our FIP TSD, page A-35 and modeling section of the RTC
document.
---------------------------------------------------------------------------

L. Cost Versus Visibility Benefit

    Comment: Our proposed controls would not result in perceptible
visibility improvements and thus should not be finalized. Commenters
also stated that the required controls result in miniscule or
insignificant visibility improvements.
    Response: We disagree that the Regional Haze Rule requires that
controls on a source or group of sources result in perceptible
visibility improvement.\123\ As we noted in our TSDs, we derived much
of our approach to the analysis of control costs and visibility impacts
from the BART Guidelines.\124\ In a situation where the installation of
BART may not result in a perceptible improvement in visibility, the
visibility benefit may still be significant, as explained by the
Regional Haze Rule: \125\
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    \123\ It is generally recognized that a change in visibility of
1.0 deciview is humanly perceptible.
    \124\ See the discussion in our FIP TSD, beginning on page 6.
    \125\ 70 FR 39129.

    Even though the visibility improvement from an individual source
may not be perceptible, it should still be considered in setting
BART because the contribution to haze may be significant relative to
---------------------------------------------------------------------------
other source contributions in the Class I area.

We accordingly disagree that selection of control measures should be
contingent upon perceptible visibility improvement. As we stated in our
previous rulemaking addressing the BART determinations in Oklahoma:
\126\
---------------------------------------------------------------------------

    \126\ 76 FR 81739.

---------------------------------------------------------------------------

    Given that sources are subject to BART based on a contribution
threshold of no greater than 0.5 deciviews, it would be inconsistent
to automatically rule out additional controls where the improvement
in visibility may be less than 1.0 deciview or even 0.5 deciviews. A
perceptible visibility improvement is not a requirement of the BART
determination because visibility improvements that are not
perceptible may still be determined to be significant.
    Thus, in our visibility improvement analysis, we have not
considered perceptibility as a threshold criterion for considering
improvements in visibility to be meaningful. Rather, we have considered
visibility improvement in a holistic manner, taking into account all
reasonably anticipated improvements in visibility and the fact that, in
the aggregate, improvements from controls on multiple sources will
contribute to progress towards the goal of natural visibility
conditions. Visibility impacts below the thresholds of perceptibility
cannot be ignored because regional haze is produced by a multitude of
sources and activities which are located across a broad geographic
area. In this action, as discussed below, we found that the required
cost-effective controls reduce visibility impairment from those sources
with the largest visibility impacts and result in meaningful visibility
benefits towards the goal of natural visibility conditions.
    As we have noted and discussed in a separate response to comment,
the results of the CAMx modeling we have utilized in our proposal
cannot be directly compared to the results of CALPUFF modeling, which
has been utilized in the vast majority of other BART and reasonable
progress/long-term strategy actions, because of differences in the
models, model inputs, and metrics used.\127\ Many of these differences
result in CAMx modeled visibility impacts and benefits that are much
lower than the CALPUFF modeled visibility impacts and benefits relied
on in other actions. We disagree with commenters that the visibility
benefits from the controls in our FIP are miniscule when the
differences in modeling analyses are considered. We observe that
several comments that are critical of the extent of the visibility
benefits have cited only to benefits from the scrubber upgrades,
omitting the total anticipated visibility benefit from all required
controls. As we discuss in the FIP TSD and in separate responses to
comments, we believe it is necessary to consider visibility benefits
based on ``clean'' natural background conditions to assess the full
potential for visibility benefits from controls. For example, we
estimated that the required controls provide for over 3 dv improvement
on 20% worst days at the Wichita Mountains when estimated using a
``clean'' background and result in improving projected visibility
conditions by 0.45 dv over the visibility conditions projected by
CENRAP and Texas for 2018 and an estimated 0.62 dv improvement in the
visibility conditions in 2018 when considering recent actual emissions
(values are for 20% worst days). The required controls result in a
greater than 5% improvement in overall visibility conditions at the
Wichita Mountains on the 20% worst days. We also estimate that the
required controls significantly reduce the projected delay in meeting
natural visibility, helping to achieve that goal 25 to 30-years earlier
at Big Bend and the Guadalupe Mountain by our projections.
---------------------------------------------------------------------------

    \127\ FIP TSD at A-35.
---------------------------------------------------------------------------

    The CENRAP modeling showed that Texas sources have significant
visibility impacts at the Wichita Mountains and the Texas Class I
areas. Our analysis identified those point sources with the greatest
contributions to visibility impairment at these Class I areas, and the
required controls reduce visibility impairment from those sources with
the largest impacts where controls were determined to be available and
reasonable for this first planning period. For example, the Monticello
and Big Brown facilities are projected to contribute approximately 1.3
Mm-\1\ and 1.2 Mm-\1\, respectively, to
visibility impairment on the 20% worst days at the Wichita Mountains in
2018 based on the CENRAP 2018 projected emissions for these
facilities.\128\ This is 1.7% and 1.5% of the total visibility
impairment at the Wichita Mountains.\129\ In our FIP TSD we noted that
Texas used an impact extinction level threshold of 0.5
Mm-\1\ (a level less than half of the estimated impact from
the Monticello or Big Brown facilities) from all sources in a state as
a threshold for inviting another state to consult. Oklahoma selected a
threshold of 1.0 Mm-\1\ to determine which states should
consult in analyzing visibility impairment at the Wichita
Mountains.\130\ We also noted that the largest projected contribution
from all point sources within a state at the Wichita Mountains after
Texas (14%) is Oklahoma at 3.9%. In other words, elimination of all
point sources in Oklahoma would result in less visibility benefit
(3.9%) than the required controls (greater than 5%). As these facts
demonstrate, the identified facilities have significant impacts on
visibility conditions. Our technical record makes it equally plain that
the required controls reduce impacts from these sources and result in
meaningful visibility benefits towards the goal of natural visibility
conditions.
---------------------------------------------------------------------------

    \128\ Light extinction, in units of inverse megameters
(Mm-\1\), is the amount of light lost as it travels over
one million meters. The haze index, in units of deciviews (dv), is
calculated directly from the total light extinction, bext, as
follows: HI = 10 ln(bext/10).
    \129\ We note that the impacts from Big Brown and other
facilities are even larger when considering recent actual emissions
rather than the CENRAP 2018 projected emissions.
    \130\ See Texas Regional Haze SIP Appendix 4-1: Summary of
Consultation Calls and Section X.A. of the Oklahoma Regional Haze
SIP.
---------------------------------------------------------------------------

    Comment: Texas' choice of 0.5 deciview as a benchmark for total
visibility improvement (from all sources) to use in its four-factor
analysis was reasonable and consistent with EPA guidelines. Under the
BART Guidelines, a source ``contributes to any visibility impairment,''
and thus becomes subject to BART, if it has an impact greater than 0.5
deciview at any Class I area. It is thus logical that a level of
visibility improvement at a single Class I area that is less than the
threshold at which a source becomes subject to BART in the first place
would be deemed insignificant for all sources. Indeed, in other
regional haze actions, EPA has ``defer[red]'' to states' consideration
of the 0.5 deciview threshold. And given Congress's special emphasis on
BART sources, Texas' reference to the BART 0.5 deciview threshold to
evaluate reasonable progress for the first planning period was
conservative, and Texas could reasonably determine that total
visibility benefits below the BART threshold for an individual source
should be deferred until a later planning period for reasonable
progress.
    Response: We disagree that Texas' choice of a 0.5 dv visibility
threshold, including the manner in which it was applied, was proper in
its analysis. First, the quote from our BART Guidelines was based on
CALPUFF modeling and not CAMx modeling. Texas extrapolated results from
CAMx modeling to estimate the visibility improvement due to all the
identified controls in their analysis and then compared it to a
threshold developed for CALPUFF modeling. As we state in the FIP TSD
and discuss in detail in our response to comments, ``[a] common metric
used in BART visibility modeling using CALPUFF is the BART screening
level of 0.5 del-dv used by most states for screening out facilities
from further BART consideration. However, there are a number of factors
that make the two analyses different and not comparable, invalidating
the use of the BART screening metric, or other such comparisons with
modeled visibility impacts for reasonable progress with

CAMx or CMAQ.'' \131\ In the FIP TSD and in separate responses to
comments we discuss the differences in the models, model inputs, and
metrics used. Many of these differences contribute to CAMx modeled
visibility impacts and benefits for reasonable progress being much
lower than the CALPUFF modeled visibility impacts and benefits for BART
relied on in other actions. As detailed in the FIP TSD, these
differences include the emission rates modeled, the metrics used and
whether the deciview impacts are calculated based on ``clean'' natural
background conditions or a ``dirty'' background based on degraded
visibility conditions projected for 2018. The CALPUFF emissions modeled
for BART are representative of maximum emission rates and are therefore
usually significantly larger (often in the range of double) than
average emission rates used in CAMx modeling for a reasonable progress
analysis. One of the main metric differences is that the CALPUFF
analysis for BART utilizes a clean background and compares the 8th
highest daily maximum impact from the specific source modeled to
compare against a 0.5 dv threshold to indicate significant impacts
while the visibility benefit that was estimated by Texas to assess the
benefit of additional controls for reasonable progress was based on a
``dirty'' or degraded background and average benefits over the 20%
worst days observed by the monitor at the Class I area which may or may
not be inclusive of the highest impact days from the specific source
modeled with CALPUFF for BART. As we discuss in detail in the FIP TSD,
because the deciview metric is a logarithmic function of extinction,
visibility impacts and improvement calculated based on ``dirty''
conditions are substantially lower than those calculated based on
natural ``clean'' conditions.\132\ These differences were not
considered in Texas' visibility analysis and selection of threshold. We
note that Texas did calculate visibility impacts compared to natural
visibility conditions and focused on the maximum impact from the
modeled sources in their BART visibility analysis, which also relied on
CAMx photochemical modeling, to determine the significance of
visibility impacts from BART sources for BART screening purposes.
However, in assessing the benefit of additional controls for reasonable
progress, Texas only considered visibility benefits averaged over the
20% worst days based on a ``dirty'' or degraded background.
---------------------------------------------------------------------------

    \131\ FIP TSD at A-35 and modeling section of the RTC document.
    \132\ FIP TSD at A-38. ``For example, see Figure A.3-5 which
shows the del-dv change due to a 10 (1/Mm) change at both the 2018
projected extinction level [``dirty background''] and the 2064
natural visibility conditions [``clean background''] extinction
level for the Wichita Mountains. In the `dirty background' case the
10 (1/Mm) yields a 1.26 del-dv, whereas in the `clean background'
case the same 10 (1/Mm) yields a 3.86 del-dv improvement. In this
example, the `clean background' situation yields a del-dv
improvement 3 times greater than the `dirty background' for the same
level of extinction improvement.
---------------------------------------------------------------------------

    The difference between comparing visibility improvement on a
``clean'' and ``dirty'' background is analogous to comparing the change
in sound volume that would occur if one person stopped singing loudly
in an empty room (clean background) to the change that would occur if
one person stops singing loudly in a room crowded with a 100 people
singing loudly (dirty background). In both cases, to return the room to
natural background sound level, the individual singers must be
addressed, but there will be little or no perceptible difference in
volume when one singer in the crowded room stops singing. To carry the
analogy further, our analysis was designed to identify the Texas
sources with the greatest visibility impact (the loudest singers) and
address them in this first planning period.
    Second, the 0.5 dv threshold in the context of BART is used to
assess the maximum total visibility impact from all BART units at a
facility. If the impact from all the BART sources at a facility is
above the threshold, then each BART unit must be evaluated for
controls, and therefore the visibility improvement anticipated from
controls would be less than 0.5 dv on a facility basis, and much less
than 0.5 dv on a unit specific basis for BART sources with multiple
BART units. For these reasons, the BART threshold of 0.5 dv has no
relation to the analysis Texas performed and is inappropriate. We also
note that we discuss in the preamble to the final Regional Haze Rule
and Guidelines for BART Determinations that a threshold less than 0.5
dv may be appropriate.\133\
---------------------------------------------------------------------------

    \133\ ``. . ., if there were 100 sources each changing
visibility by 0.1 deciviews, the total impact would be a 10-deciview
change in visibility. In this hypothetical example, all 100 sources
would be contributing, in equal amounts, to substantial visibility
impairment . . . .'' 70 FR 39121.
---------------------------------------------------------------------------

    Even setting aside Texas' approach of aggregating sources with
varying impacts on visibility, the use of a 0.5 dv threshold as applied
by Texas for determining the significance of visibility benefits of all
controls combined would have ensured that little visibility improvement
would occur during this planning period. Texas and Oklahoma
acknowledged in their SIP submittals that sources in Texas have a large
impact on visibility at the Wichita Mountains; indeed, the visibility
impacts at this Class I area from Texas point sources are several times
greater than the impacts from Oklahoma's own point sources. Based on
CENRAP 2018 modeling, all point sources in Texas combined have a
visibility impact in terms of light extinction of 10.58
Mm-\1\ at the Wichita Mountains, which based on ``dirty''
2018 CENRAP projected background conditions equals a 1.34 dv impact for
the 20% worst days. Therefore, adopting the 0.5 dv threshold, using
Texas' approach to assessing reasonable progress measures, would
require the identification of a control set large enough (and with a
correspondingly large total cost) to address over one-third of the
total impacts from all Texas point sources, before the visibility
benefit would be considered significant. To put this into context,
achieving the national goal at the Texas Class I areas will require
just over ten deciviews of improvement (approximately a reduction in
light extinction of 35 Mm-\1\), a task that EPA has
estimated could reasonably take until 2064. Given that the Regional
Haze Rule recognizes that improving visibility is an iterative process
that will take many years, declining to establish any additional
measures to ensure reasonable progress until Texas could identify a
combined set of cost-effective and affordable controls that could
achieve 0.5 dv or more improvement is unreasonable, especially when
there are cost-effective and affordable controls that result in
meaningful visibility improvements towards the goal of natural
conditions. We also note that delaying even incremental action during
this first planning period pushes out the likely date of achieving
natural conditions well past 2064.
    Comment: Earthjustice stated that based on its analysis,\134\ our
proposed FIP would result in billions of dollars in public health
benefits. According to Earthjustice, the same pollutants that cause
visibility impairment also cause significant public health impacts.
Nitrogen oxides are precursors to ground level ozone, which is
associated with respiratory diseases, asthma attacks, and decreased
lung function. Similarly, sulfur dioxide increases asthma symptoms,
leads to increased hospital visits, and can form particulates that
aggravate respiratory

and heart diseases and cause premature death. We received many
additional comments from groups, private citizens, and a member of
Congress that expressed similar public health, welfare, and economic
benefits, including ecosystem and tourism benefits.
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    \134\ Written Report of George D. Thurston Regarding the Public
Health Benefits of EPA's Proposed Rulemaking Regarding Texas And
Oklahoma Regional Haze, April 18, 2015. Visibility And Health
Modeling Technical Support Document to Comments Of Conservation
Organizations, prepared by Dr. H. Andrew Gray, April 20, 2015.
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    Response: We appreciate the commenters' concerns regarding the
potential health benefits of air pollution controls to improve air
quality In Class I areas. We generally agree that the same emissions
that cause visibility impairment can also cause health related
problems, such as respiratory ones. We agree that although our action
addresses visibility impairment, our FIP requires emissions reductions
that will result in co-benefits for public health, welfare, and
economic benefits. However, for purposes of this action, we are not
authorized to specifically consider these types of benefits under the
regional haze program.

M. Natural Conditions

    Comment: We received comments from the TCEQ and a number of
facilities and trade organizations that we should have approved Texas'
natural conditions calculations for Big Bend and the Guadalupe
Mountains. These commenters state that Texas rightly discarded our
default values in favor of its refined estimates in accordance with our
guidance. In doing so, these commenters state Texas rightly assumed all
the visibility impairment due to coarse mass and fine soil was due to
natural causes. Earthjustice stated that Texas did not properly support
its calculations. Earthjustice stated that because Carlsbad Caverns in
New Mexico (approximately 40 miles from the Guadalupe Mountains) uses
the same monitor and we previously approved New Mexico's use of our
default natural conditions estimate, allowing Texas to use a different
value is inconsistent.
    Response: We agree with the commenters that the Regional Haze Rule
and our guidance \135\ do allow states to develop an alternate approach
to estimate natural visibility conditions. However, in adopting an
alternate approach, that approach must be fully supported and
documented. The TCEQ's analysis and our own observations do support a
conclusion that much of the contribution of coarse mass and fine soil
to the visibility impairment at the Guadalupe Mountains and Big Bend is
due to natural sources. They do not demonstrate that 100% of this
contribution is due to natural sources. Like us, the FLMs did not agree
with the assumption that 100% of the coarse mass and soil was natural,
and pointed to human activity in the region. The FLMs ``suggested that
the commission could judiciously use 80 percent as the natural source
of coarse and fine dust and 20 percent of coarse and fine dust due to
human activity.'' \136\ Although the TCEQ presented the FLM's
suggestion in its SIP, it ultimately adopted its own estimate, based on
its unproven 100% coarse mass and soil assumption. Another option that
we noted in our proposal that was open to the states, and the one we
used in proposing the natural conditions for the Texas Class I areas in
our FIP, was the ``new IMPROVE equation'' that was adopted for use by
the IMPROVE Steering Committee in December 2005.\137\ This refined
version of the IMPROVE equation provided more accurate estimates of
some of the factors that affect the calculation of light extinction.
The TCEQ started with this refined version of the IMPROVE equation, but
further altered some of its parameters concerning the contributions of
coarse mass and fine soil, without adequate documentation. We found
that the TCEQ's documentation was flawed, but we are under no
obligation to follow in the TCEQ's footsteps and make whole its
methodology, when we had already provided guidance with default natural
visibility conditions, which were further refined by the 2005 IMPROVE
Steering Committee. We agree with Earthjustice that it is reasonable to
expect that both Carlsbad Caverns and the Guadalupe Mountains should
have the same or nearly the same natural conditions. We urge Texas and
New Mexico to work together to resolve this issue in the next planning
period. Even as we are disapproving Texas' natural conditions
estimates, we conclude that our determinations for emissions
limitations for EGUs in the FIP for the first planning period would be
justified on the basis of natural conditions estimates at either levels
in the SIP or the levels in the FIP, given the level of visibility
impairment at each Class I area above the different estimates for
natural conditions and the availability of cost-effective controls at
those sources with the largest visibility impacts that result in
meaningful progress towards the natural visibility goal. Furthermore,
as we noted in our proposal, based on both our recalculated natural
conditions and the Texas natural condition estimates that we are
disapproving, Texas' Class I areas are not projected to meet the
uniform rate of progress in 2018 according to the CENRAP modeling and
are not projected to meet the goal of natural visibility conditions by
2064.\138\
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    \135\ Guidance for estimating natural visibility conditions
under the Regional Haze Rule, EPA, September 2003, p 1-11.
    \136\ Appendix 2-2 of the Texas Regional Haze SIP.
    \137\ The IMPROVE program is a cooperative measurement effort
governed by a steering committee composed of representatives from
Federal agencies (including representatives from EPA and the Federal
Land Managers) and regional planning organizations. See our proposal
for additional information on the IMPROVE program and the new
IMPROVE equation.
    \138\ 79 FR 74832
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    Comment: Luminant's contractor AECOM noted that in developing its
SIP, Texas found that some of the haziest days at its two Class I areas
are the result of uncontrollable natural conditions such as windblown
dust and wildfire emissions. AECOM developed a daily threshold
percentage of total aerosol extinction \139\ caused by CM, OMC, and
soil species for each Texas Class I area. This threshold was developed
by constructing histograms of the 20% worst days for a ``noticeable
step-up in frequency'' of higher contributions of CM, OMC, and soil.
AECOM then added this additional extinction to our default natural
conditions extinctions, resulting in alternate natural conditions
estimates that it suggests we adopt. AECOM states that with these new
natural conditions, the uniform rates of progress will be met for Big
Bend and the Guadalupe Mountains.
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    \139\ Note that although natural conditions are ultimately
expressed in deciviews (dv), the IMPROVE equation first calculates
aerosol extinctions by contributions to extinction by all relevant
species, of which coarse mass and fine soil are two. Total
extinction is then converted to deciviews.
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    Response: Although AECOM restricts its assumption to specific days,
it nevertheless assumes that all coarse mass, organic mass carbon and
soil visibility impacts at Big Bend and the Guadalupe Mountains are
100% due to natural causes. AECOM provides no documentation to support
this conclusion. Although we agree that much of those species
contributions are due to natural sources, we do not believe that all of
these contributions are due to natural sources. Fires, windblown CM and
soil do have both anthropogenic and natural origins. As an initial
matter, we believe that AECOM erred in assembling its histograms. We
reconstructed these histograms and note they differ significantly from
those AECOM presented. In fact, we believe the ``noticeable step-up in
frequency of higher contributions of CM, OMC, and soil (i.e., from
right to left)'' that AECOM points to is more muted for

both Class I Areas when the histograms are assembled correctly, to the
point it is essentially absent for the Guadalupe Mountains. We noted
other problems that cause us to conclude that AECOM's methodology
should not be used. Moreover, under the Regional Haze Rule, even if it
were concluded that the uniform rate of progress will be met for Big
Bend and the Guadalupe Mountains, this does not change the requirement
that the reasonable progress goals be selected based on proper
consideration of the four factors. As discussed in the proposal and the
RTC document, the uniform rate of progress is not a ``safe harbor''
under the Regional Haze Rule.

N. Consistency With Our Other Regional Haze Actions

    We received a number of comments alleging specific instances of
inconsistency with our previous SIPs and FIPs, as well as with our
regional consistency rules at 40 CFR 56.5(a)(1) and (2). We have
extracted all of these alleged instances of inconsistency, and we
address them in detail in a separate consistency section within our RTC
document. We recognize that we have a duty to ensure our regional haze
actions are carried out in accordance with the CAA, Federal
regulations, and our policies, and are as consistent as reasonably
possible with other regional haze actions as required under our
regional consistency rules (40 CFR 56.5(a)(2)), recognizing the fact-
specific nature of individual regional haze plans and determinations.
As we discuss below, we believe that in this action, which is one of
the last remaining regional haze SIP reviews of the first planning
period, we have been as consistent with our previous actions as is
reasonably possible. We disagree that our action is inconsistent with
the reasonable progress requirements or our prior SIP actions. While
our regional consistency regulations and policies require us to carry
out our actions pursuant to the CAA in a consistent manner across EPA
regions as reasonably as possible, they do not require uniformity
between those actions in all circumstances and instead, ``allow for
some variation'' in actions taken in different regions.\140\ As
explained in detail in the separate consistency section of our RTC
document, we believe that we have acted consistently with the CAA and
our regional haze regulations in taking these specific actions for
Texas, and in accordance with 40 CFR 56.5, our final action is ``as
consistent as reasonably possible'' \141\ with other actions given the
specific facts presented in Texas and Oklahoma. We thus disagree with
these comments. We note that staff from Region 6 have worked closely
with EPA headquarters throughout the proposed and final actions
regarding the Texas and Oklahoma regional haze requirements, including
in the analysis and conclusions contained in the SIP and FIP
determinations included in this final rule. As explained fully in our
RTC document, we note that commenters' citation to the National
Environmental Development Association's Clean Air Project v. EPA (NEDA
CAP) case is distinguishable from our action here.\142\
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    \140\ 80 FR 50258.
    \141\ 40 CFR 56.5(a)(2).
    \142\ National Environmental Development Association's Clean Air
Project v. EPA (NEDA CAP), No. 13-1035 (D.C. Cir., May 30, 2014).
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    Developing solutions to the complex problem of regional haze
requires effective consultation among states. During the first planning
period, the states worked together through RPOs to help develop their
regional haze SIPs. To assist in this effort, we provided tens of
millions of dollars to the RPOs following the issuance of the 1999
Regional Haze Rule to fund the development of the technical tools and
analyses necessary to address regional haze and to facilitate
consultation among the states. The states set up five RPOs to address
visibility impairment from a regional perspective. The technical
analyses done by the RPOs for the first round of regional haze SIPs
greatly increased the understanding of the problem of visibility
impairment at the Federal Class I areas, including that of the specific
contribution of different species of pollutants.
    Given the regional differences in the degree of visibility
impairment, the pollutants of concern, and the impacts of fire and
international emissions, we did not prescribe a one size fits all
approach to reasonable progress. The RPOs accordingly adopted somewhat
different approaches to recommending potential measures to ensure
reasonable progress. However, the RPOs and the states all agreed that
large stationary sources of SO2 are the typically the
primary cause or one of the primary causes of anthropogenic visibility
impairment at this time. In addition, in some regions of the country,
the RPOs and the states also recognized NOX as a similarly
important cause of visibility impairment.
    In our review of the regional haze SIPs, we have attempted to take
into account the differences among states in assessing the
reasonableness of each state's SIP submittal. By its nature, each
regional haze decision is a very fact specific determination requiring
the consideration of multiple factors. After examining all instances of
perceived inconsistency with other actions, we believe that when all of
the factors are considered in their full context, the situation for
Texas and Oklahoma differs sufficiently from these other actions cited
as being inconsistent with this action to warrant the approach that we
have taken. Furthermore, we found that in many instances some
commenters reproduced incomplete quotes from our previous actions, or
otherwise took those quotes out of their proper context, leading to an
inaccurate characterization of the facts in some cases.\143\ Often a
sentence immediately preceding or following the reproduced quote in
fact provided that context. In other cases, commenters called out a
particular difference between some aspect of our technical analysis in
comparison to what was used in a previous SIP or FIP, without providing
the reasoning for those differences. In many other cases, the
commenters simply misunderstood or otherwise misinterpreted the
facts.\144\
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    \143\ See for example: (1) Our response to Luminant's comment
concerning the ``contribution of coal combustion sources'' in the
Alaska SIP, (2) Our response to CCP's comment concerning the
consideration of visibility in the North Dakota SIP, or (3) Our
response to CCP's comment concerning Texas' use of a $2,700/ton cost
threshold.
    \144\ See for example: (1) The TCEQ's comment letter at page 14
concerning the Arkansas-Missouri consultations, (2) the AECT's
comment letter at page 9 that we did not allow Texas to consider
emissions from natural sources, such as wildfires and dust storms,
in establishing natural visibility conditions, (3) The CCP's comment
letter at page 8 concerning Texas' use of a $2,700/ton cost
threshold.
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    Many commenters compared our CAMx modeled visibility impairments or
improvements with those in other actions modeled using CALPUFF and
concluded that our proposed visibility improvements were not enough to
merit controls when compared to those other actions. These commenters
universally failed to account for the differences between these two
modeling platforms, the model inputs, and the metrics used.\145\ Many
of these differences result in CAMx modeled visibility impacts and
benefits that are much lower than the CALPUFF modeled visibility
impacts and benefits relied on in other actions. As we have noted and
discussed in separate responses to comments and the FIP TSD, the
results

of the CAMx modeling we have utilized in our analysis cannot be
directly compared to the results of CALPUFF modeling, which has been
utilized in the vast majority of BART and other reasonable progress/
long-term strategy actions.
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    \145\ See our FIP TSD, beginning on page A-35, in which we
explain why key differences in CALPUFF and CAMx preclude the
comparison of their respective results and why CAMx results for RP
are generally much less than CALPUFF results for BART for the same
facility/emissions due to the model inputs and metrics used.
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    Some commenters criticized us for disapproving the reasonable
progress and long-term strategy consultations between Oklahoma and