Document ID: EPA-R09-OAR-2011-0130-0089
Agency: epa
Document Type: Rule
Title: Approvals and Promulgations of Air Quality Implementation Plans: Nevada; Regional Haze State and Federal Implementation Plans; BART Determination for Reid Gardner Generating Station
Posted Date: 2012-08-23T04:00Z

[Federal Register Volume 77, Number 164 (Thursday, August 23, 2012)]
[Rules and Regulations]
[Pages 50936-50952]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-20503]

=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2011-0130, FRL 9700-4]

Approval and Promulgation of Air Quality Implementation Plans; 
Nevada; Regional Haze State and Federal Implementation Plans; BART 
Determination for Reid Gardner Generating Station

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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

SUMMARY: EPA is approving in part and disapproving in part the 
remaining portion of the Nevada Regional Haze State Implementation Plan 
(SIP) that implements the Clean Air Act (CAA) Regional Haze Rule 
requiring states to prevent any future and remedy any existing man-made 
impairment of visibility in mandatory Class I areas through a regional 
haze program. EPA is approving Nevada's selection of a nitrogen oxide 
(NOX) emissions limit of 0.20 lb/MMBtu as Best Available 
Retrofit Technology (BART) for the Reid Gardner Generating Station 
(RGGS) at Units 1 and 2. EPA is disapproving two provisions of Nevada's 
BART determination for NOX at RGGS: The emissions limit for 
Unit 3 and the compliance method for all three units. EPA is 
promulgating a Federal Implementation Plan (FIP) which replaces the 
disapproved provisions by establishing a BART emissions limit for 
NOX of 0.20 lb/MMBtu at Unit 3, and a 30-day averaging 
period for compliance on a heat input-weighted basis across all three 
units. We encourage the State to submit a revised SIP to replace all 
portions of our FIP. Moreover, we stand ready to work with the State to 
develop a revised plan.

DATES: This rule is effective on September 24, 2012.

ADDRESSES: EPA has established docket number EPA-R09-OAR-2011-0130 for 
this action. Generally, documents in the docket are available 
electronically at http://www.regulations.gov or in hard copy at EPA 
Region 9, 75 Hawthorne Street, San Francisco, California. Please note 
that while many of the documents in the docket are listed at http://www.regulations.gov, some information may not be specifically listed in 
the index to the docket and may be publicly available only at the hard 
copy location (e.g., copyrighted material, large maps, multi-volume 
reports or otherwise voluminous materials), and some may not be 
available at either locations (e.g., confidential business 
information). To inspect the hard copy materials, please schedule an 
appointment during normal business hours with the contact listed 
directly below.

FOR FURTHER INFORMATION CONTACT: Thomas Webb, U.S. EPA, Region 9, 
Planning Office, Air Division, AIR-2, 75 Hawthorne Street, San 
Francisco, CA 94105. Thomas Webb can be reached at telephone number 
(415) 947-4139 and via electronic mail at webb.thomas@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document, wherever ``we,'' 
``us,'' or ``our,'' is used, we mean the United States Environmental 
Protection Agency (EPA).

Table of Contents

I. Background and Purpose
II. EPA Responses to Public Comments
III. Summary of EPA Actions
IV. Statutory and Executive Order Reviews

I. Background and Purpose

    A detailed explanation of the requirements for regional haze SIPs 
and EPA's analysis of the Nevada Division of Environmental Protection's 
(NDEP) BART determination for NOX at RGGS is provided in our 
Notice of Proposed Rule Making and is not restated here. See 77 FR 
21896 (April 12, 2012).
    RGGS consists of four coal-fired boilers, three of which are BART-
eligible units with generating capacity of 100 megawatts (MW) each. A 
fourth unit (250 MW) is not BART-eligible. Nevada Energy, the owner of 
RGGS, performed a NOX BART analysis for the three BART-
eligible units at RGGS and submitted the results of its analysis to 
NDEP.\1\ In its BART analysis, Nevada Energy considered several 
NOX control technologies and evaluated the cost of 
compliance and visibility improvement associated with each technology. 
In preparing the SIP, NDEP relied on certain aspects of Nevada Energy's 
analysis while performing updated analyses for other aspects.
---------------------------------------------------------------------------

    \1\ Nevada Energy BART Analysis Reports, Reid--Gardner--1--10-
03-08.pdf, Reid--Gardner--2--10-03-08.pdf, Reid--Gardner--3--10-03-
08.pdf. Available in Docket Item No. EPA-R09-OAR-2011-0130-0007.
---------------------------------------------------------------------------

    EPA proposed to fully approve Nevada's SIP on June 22, 2011 (see 76 
FR 36450), but received numerous comments on our proposed approval of 
the BART determination for NOX at RGGS. A detailed 
description of those comments is in our final rule, which approved all 
of the Nevada regional haze SIP, except for the BART determination for 
NOX at RGGS. See 77 FR 17334 (March 26, 2012). After 
reviewing the public comments, EPA performed additional analyses of the 
cost-effectiveness and visibility improvement associated with the 
various NOX control technologies considered by NDEP in 
determining BART for NOX at RGGS. Based upon these 
additional analyses, EPA did not take final action on the chapters of 
the SIP containing the NOX BART determination for RGGS, 
including the corresponding emission limits and schedules of compliance 
for NOX at RGGS. Specifically, EPA did not take final action 
on sections 5.5.3, 5.6.3 and 7.2 of NDEP's SIP, addressing the 
NOX BART control analyses, visibility improvement, and 
implementation at RGGS.

[[Page 50937]]

    EPA published a new proposal to partially approve and partially 
disapprove NDEP's BART determination for NOX at RGGS on 
April 12, 2012. See 77 FR 21896. Based on its additional analyses 
described above, EPA proposed revised control cost calculations for 
installation and operation of low NOX burners (``LNB'') and 
overfire air (``OFA'') combined with either selective non-catalytic 
reduction (SNCR) or selective catalytic reduction (SCR) technology.\2\ 
EPA also performed new CALPUFF visibility modeling to evaluate the 
visibility improvement from installing and operating LNB with OFA and 
either SNCR or SCR.
---------------------------------------------------------------------------

    \2\ As explained in our proposal, NDEP originally selected 
rotating opposed fire air (ROFA) with Rotamix\TM\ as BART for RGGS 
Units 1-3, but more recently informed us that it will submit a SIP 
that evaluates the substitution of SNCR with LNB and OFA for ROFA 
with Rotamix\TM\. 77 FR at 21898. Therefore, we are not approving 
NDEP's prior selection of ROFA with Rotamix\TM\ as the control type 
for BART. Rather, we are approving NDEP's BART emissions limits for 
Units 1 and 2 of 0.20 lb/MMBtu. According to the most recent 
information received from NDEP, these limits can be achieved either 
with ROFA with Rotamix\TM\ or with SNCR with LNB and OFA. ROFA with 
Rotamix\TM\ combines a conventional SNCR system with a proprietary 
air and reagent injection system.
---------------------------------------------------------------------------

    As discussed in detail in our responses to comments, EPA's 
independent modeling results showed a very small visibility improvement 
at the Grand Canyon National Park (GCNP) as a result of installing and 
operating SCR with an 85 percent reduction in NOX on all 
three units. The modeled visibility improvement for this scenario was 
0.38 dv at the GCNP. The incremental visibility improvement for 
installing LNB with OFA and SCR rather than LNB with OFA and SNCR was 
only 0.10 dv at GCNP.
    EPA has considered the comments we received on our proposed 
approval and proposed disapproval. In this final action, EPA is 
approving NDEP's determination that NOX BART for RGGS for 
Units 1 and 2 is an emissions limit of 0.20 lb/MMBtu that can be 
achieved by installing and operating LNB with OFA and SNCR. EPA is 
disapproving NDEP's NOX BART emissions limit of 0.28 lb/
MMBtu for Unit 3. EPA is also disapproving the 12-month rolling average 
that NDEP adopted for all three units. Concurrently, EPA is finalizing 
a FIP for RGGS setting a NOX emissions limit of 0.20 lb/
MMBtu for Unit 3 and a 30 successive boiler operating day (BOD) rolling 
NOX emissions limit on a heat input-weighted average across 
all three units.\3\ This represents a change to the averaging period 
included in our proposed action on April 12, 2012, which was based on a 
straight 30 calendar day average. EPA concludes that the change is a 
logical outgrowth of the proposal and the comments received.
---------------------------------------------------------------------------

    \3\ Throughout the preamble we use the term ``heat input-
weighted average'' in describing the 30 successive day rolling 
emission limit. The regulation does not actually average the data 
for the 3 units, but sums the total NOX lb/hr over 30 
boiler operating days and divides that total NOX lb by 
the sum of the heat input over the same days. The use of the term 
``heat input-weighted average'' is meant to be descriptive of the 
time period and of the fact that it combines all three units to 
determine compliance.
---------------------------------------------------------------------------

    EPA takes very seriously a decision to disapprove these provisions 
in Nevada's plan, as we believe that it is preferable that all emission 
control requirements needed to protect visibility be implemented 
through the Nevada SIP. A revised state plan need not contain exactly 
the same provisions that EPA has included in the FIP, but EPA must be 
able to find that the state plan is consistent with the requirements of 
the CAA. Further, EPA's oversight role requires that we assure fair 
implementation of CAA requirements by states across the country, even 
while acknowledging that individual decisions from source to source or 
state to state may not have identical outcomes. In this instance, we 
believe that NDEP's NOX BART determination for RGGS 
generally meets those requirements except for the specific emissions 
limit for Unit 3 and the compliance averaging time. As a result, EPA 
believes this combined approval, disapproval, and FIP is consistent 
with the CAA at this time, while full approval of the SIP would be 
inconsistent with the CAA. We look forward to working with NDEP to 
replace the FIP provisions with a revised SIP.

II. EPA Responses to Public Comments

    EPA received written and oral comments before the close of the 
public comment period on June 4, 2012. We received major comments in 
writing from a consortium of environmental and conservation 
organizations \4\ (``Consortium''), the National Park Service, the 
Nevada Division of Environmental Protection, Nevada Energy, the Moapa 
Band of Paiutes, Clark County Rural Democratic Caucus, and about ten 
individuals. We received comments from the two public hearings held 
near RGGS on May 3, 2012, that were attended by about 150 people, many 
of whom testified. We also received over 13,000 comments from mass 
mailings initiated by Sierra Club, National Parks Conservation 
Association, and CREDO Action (Rural Nevada Democratic Caucus). The 
comment letters, transcripts of the public testimony, and samples of 
the mass mailers are available for review online in Docket EPA-R09-OAR-
2011-0130 at http://www.regulations.gov. While the written comments 
focus largely on the cost of compliance and degree of visibility 
improvement associated with SCR and SNCR, other topics are included. 
The oral comments provided as testimony at the public hearings focus 
largely on SCR and SNCR, but with an emphasis on sustaining jobs in the 
local community and the health issues experienced by the Moapa Band of 
Paiutes who live adjacent to Reid Gardner. We respond below to the full 
range of comments received from all sources.
---------------------------------------------------------------------------

    \4\ The Consortium's comment letter was signed by 
representatives of Sierra Club, National Parks Conservation 
Association, Moapa Band of Paiutes, Citizens for Dixie's Future, 
Defend Our Desert, Friends of Gold Butte, Grand Canyon Trust, and 
Western Resource Advocates.
---------------------------------------------------------------------------

 A. National Consistency

    Comment 1: EPA's proposed BART determination for NOX at 
RGGS is inconsistent with EPA's decision to require SCR on other 
similar facilities including the San Juan Generating Station in New 
Mexico.
    Response 1: It is important to note that EPA is approving Nevada's 
determination that the NOX BART for RGGS is the emissions 
rate achievable using modern LNB with OFA and SNCR. We are approving 
NDEP's decision to reject requiring SCR as NOX BART because 
we believe that NDEP's conclusion, that the small improvement in 
visibility at GCNP did not justify the cost of LNB with OFA and SCR 
technology, is adequately supported by the facts in this situation.\5\ 
Congress crafted the CAA to provide for states to take the lead in 
developing implementation plans, but balanced that decision by 
requiring EPA to ensure the plans meet the requirements of the CAA. 
EPA's review of a SIP is not limited to a ministerial approval of a 
state's decisions. EPA must evaluate whether a state considered the 
appropriate factors and acted reasonably in doing so. In undertaking 
such a review, EPA does not usurp a state's authority but ensures that 
such authority is reasonably exercised.
---------------------------------------------------------------------------

    \5\ In future discussions comparing SNCR and SCR, both 
technologies include use of modern LNB and OFA to meet the emission 
rates discussed in this rule. We will not continue to list the 
combustion controls separately.
---------------------------------------------------------------------------

    The CAA and EPA's regional haze regulations set forth five factors 
that a state should evaluate to reach a BART determination. However, 
the CAA and our regulations provide flexibility to the

[[Page 50938]]

state in deciding how the factors in the analysis are weighed. 
Moreover, for power plants that are smaller than 750 MW, our 
regulations allow the state to conduct a five-factor analysis that does 
not conform in all respects to our BART Guidelines for larger sources. 
See 70 FR 39131 (July 6, 2005).
    For San Juan Generating Station and other examples cited in the 
comments, EPA disapproved BART determinations submitted by the states 
because they did not meet the CAA requirements. Under CAA section 
110(c), EPA is required to promulgate a Federal Implementation Plan 
following disapproval of a state implementation plan submission in 
whole or in part. EPA's role of making the initial BART determination 
in a FIP is not directly comparable to EPA's role in deciding whether 
the state's SIP is approvable. EPA and the states generally consider 
the same factors in the initial BART determination but may weigh those 
factors differently provided the determination in each case is 
reasonable. BART determinations are case by case analyses. For example, 
in the case of San Juan Generating Station, EPA modeled very 
significant visibility improvement in numerous surrounding Class I 
areas resulting from emissions reductions associated with SCR, and thus 
concluded based on its five factor analysis that SCR was BART.\6\ 
However, at RGGS, the visibility improvement from SCR compared to SNCR 
is very small. The units at San Juan Generating Station are also 
significantly larger than the units at RGGS, and the application of the 
BART Guidelines is mandatory when performing the five-factor analysis. 
This is not the case for RGGS.
---------------------------------------------------------------------------

    \6\ Per 76 FR 503, Table 8, EPA Region 6 modeled visibility 
benefits of 3.11 deciviews (single Class I area with greatest 
impact), and 21.69 deciviews (cumulative, all Class I areas within 
300 km).
---------------------------------------------------------------------------

    NDEP on the other hand indicated that it had determined SNCR rather 
than SCR was NOX BART for RGGS based on weighing the small 
incremental visibility improvement of SCR against its incremental cost 
effectiveness. When EPA reviewed NDEP's NOX BART 
determination, we found problems in the method NDEP used to calculate 
cost-effectiveness and in the assumptions on which the modeling was 
based. Accordingly, EPA independently calculated cost-effectiveness and 
performed new modeling. In our review, EPA considered both average and 
incremental cost-effectiveness and visibility improvement. The results 
of our own analysis of the incremental visibility improvement and cost 
for SCR differ from NDEP's analysis in certain respects, but support 
NDEP's decision to establish an emissions limit that can be achieved by 
installing SNCR technology.
    NDEP reasonably determined that NOX emissions reductions 
achievable with SNCR would provide some visibility improvement at GCNP 
at a reasonable cost. Our decision to approve NDEP's determination that 
the emissions rate achievable with LNB with OFA and SNCR is 
NOX BART for RGGS is consistent with other national BART SIP 
approvals as well as proposed FIPs and final FIPs. See, e.g., 77 FR 
24385 (April 24, 2012) (Final Maine SIP approval); 77 FR 24027 and 
24034 (April 20, 2012) (Proposed Montana FIP); and 77 FR 20894 (April 
6, 2012) (Final North Dakota FIP). Other SIPs have rejected more 
effective controls such as SCR if those controls were found to provide 
little visibility improvement relative to significant cost. See, e.g., 
76 FR 80754, 80758 (Dec. 27, 2011) (Final Kansas SIP approval \7\); 76 
FR 16168 (March 22, 2011) (Proposed Oklahoma SIP approval \8\). 
Therefore, our approval of NDEP's BART determination is consistent with 
EPA's action on other regional haze SIPs as well as proposed and final 
EPA FIPs.
---------------------------------------------------------------------------

    \7\ Jeffrey Energy Center 1 and 2, La Cygne Unit 2.
    \8\ EPA Region 6 proposed approval of the NOX 
portions of the Oklahoma RH SIP. See Muskogee Station Unit 4 and 5, 
Sooner Station Units 1 and 2.
---------------------------------------------------------------------------

    In summary, EPA thoroughly and independently reviewed NDEP's basis 
for selecting a NOX emissions rate achievable with SNCR as 
BART for RGGS rather than selecting SCR. In reaching this 
determination, NDEP weighed the small visibility improvement against 
the costs of the more effective control option. EPA calculated a lower 
average and incremental cost-effectiveness value than NDEP. EPA's 
modeling relied on the regulatory version of the CALPUFF modeling 
system and improved meteorological inputs, and predicted much less 
visibility improvement at GCNP from selecting SCR as NOX 
BART (average: 0.38 dv, incremental: 0.10 dv). We also evaluated the 
visibility improvement that would result at four other Class I areas 
within 300 km of RGGS. Our modeling indicated that SCR would result in 
only minimal improvement at these four areas. Although we found 
shortcomings in NDEP's cost-effectiveness and visibility improvement 
values, we are taking final action to approve NDEP's conclusion that 
the small visibility improvement does not justify the cost of requiring 
SCR as NOX BART. The comment before us does not change our 
decision that NDEP reasonably applied the statutory and regulatory 
factors to determine that the NOX BART emission rate 
achievable from SNCR (0.20 lb/MMBtu) is BART for RGGS.
    EPA acknowledges that NDEP has greater discretion in applying the 
BART factors because RGGS is an electric generating unit smaller than 
750 MW. In evaluating SIPs, EPA exercises judgment about SIP adequacy, 
not just to meet and maintain the National Ambient Air Quality 
Standards (NAAQS), but also to meet other requirements that do not have 
a specific ambient standard, such as visibility at Class I areas. In 
this case, Congress established a requirement for BART, and EPA is 
charged to assure that states meet the requirement. Here, contrary to 
the commenter's assertion, we are exercising judgment within the 
parameters laid out in the CAA and consistent with other actions 
nationally applying our regional haze regulations. Our interpretation 
of our regulations and the CAA, and our technical judgments, are 
entitled to deference. See, e.g., Michigan Dep't. of Envtl. Quality v. 
Browner, 230 F.3d 181 (6th Cir. 2000); Connecticut Fund for the Env't., 
Inc. v. EPA, 696 F.2d 169 (2nd Cir. 1982); Voyageurs Nat'l Park Ass'n 
v. Norton, 381 F.3d 759 (8th Cir. 2004); Mont. Sulphur & Chem. Co. v. 
United States EPA, 2012 U.S. App. LEXIS 1056 (9th Cir. January 19, 
2012).
    Therefore, we are finalizing our approval of NDEP's NOX 
BART emissions rate of 0.20 lb/MMBtu, achievable using modern LNB with 
OFA and SNCR, for RGGS with two exceptions. For Unit 3, EPA is taking 
final action disapproving the SIP and promulgating a FIP setting the 
NOX emissions limit at 0.20 lb/MMBtu. In addition, EPA is 
finalizing a 30 successive boiler operating day rolling NOX 
emissions FIP limit on a heat input-weighted average across all three 
units rather than the 12-month rolling average NDEP included in its 
SIP, which EPA is disapproving.

B. BART Evaluation Process

    Comment 2: EPA did not correctly follow the BART process for 
evaluating the five factors, which should have resulted in selecting 
SCR and an emission limit corresponding to 90 percent control of 
NOX.
    Response 2: EPA was not conducting a BART analysis, but was 
reviewing the adequacy and reasonableness of NDEP's BART analysis. NDEP 
noted that RGGS is not the size of a facility for which application of 
the BART guidelines is mandatory when performing its five-factor 
analysis. In evaluating the five factors, NDEP evaluated visibility

[[Page 50939]]

impacts by relying on visibility modeling included in the BART analysis 
submitted to NDEP by Nevada Energy. NDEP concluded that the small 
improvement in visibility that could be achieved with SCR did not 
justify the cost of SCR. We are generally approving the State's BART 
determination because we find NDEP's conclusions as to the appropriate 
level of BART controls to be reasonable..
    NDEP did not consider a SCR system that would achieve 90 percent 
reduction. For SCR, NDEP assumed the technology would achieve control 
efficiencies of 78 to 82 percent. See Table 1 in 77 FR 21900 (April 12, 
2012). The significance of the control efficiency assumption is that it 
affects the cost-effectiveness of the control technology. Cost-
effectiveness ($/ton) is calculated by dividing the total annual cost 
($) by the total annual tons of the pollutant reduced (tons). Assuming 
that two different levels of control (e.g., 82 percent versus 90 
percent) bear the same cost, higher control efficiency assumptions 
(e.g., 90 percent) will result in lower cost per ton values because the 
denominator in the equation is larger.
    In reviewing the reasonableness of NDEP's NOX BART 
determination, EPA assumed a higher efficiency than NDEP. EPA 
determined that SCR could reduce 85 percent of the NOX 
emissions from the stack exhaust. EPA continues to find that the 
correct assumption for the removal efficiency in this case is 85 
percent rather than 90 percent. One of the factors EPA considered is 
that RGGS is not limited in its coal purchase by a contract. RGGS may 
purchase coal on the spot market, meaning that the rank \9\ and 
nitrogen content of the coal combusted may vary. Bituminous coals from 
Utah have a very high btu per pound, which leads to higher 
NOX produced during combustion. Coals with high nitrogen 
content also produce more NOX when combusted.\10\ Since RGGS 
has access by rail line to a number of different ranks of coal with 
varying nitrogen, these factors can affect the emission level that can 
be achieved with the SCR.
---------------------------------------------------------------------------

    \9\ Coal rank: The classification of coals according to their 
degree of progressive alteration from lignite to anthracite. In the 
United States, the standard ranks of coal include lignite, 
subbituminous coal, bituminous coal, and anthracite and are based on 
fixed carbon, volatile matter, heating value, and agglomerating (or 
caking) properties. http://205.254.135.7/tools/glossary/index.cfm?id=C.
    \10\ Journal of the Air & Waste Management Association, Volume 
55, September 2005, Nitrogen Oxides Emission Control Options for 
Coal-Fired Electric Utility Boilers.
---------------------------------------------------------------------------

    Assuming arguendo that EPA agreed with the comment that SCR should 
achieve 90 percent reduction continuously, we would not necessarily 
change our decision to approve NDEP's BART determination. As noted 
above, 90 percent control efficiency assumption would lead to a lower 
average and incremental cost-effectiveness. Even with that, NDEP's BART 
determination may have been reasonable based on weighing the small 
incremental visibility improvement of SCR against its incremental cost 
effectiveness. However, that issue was not before EPA in this action 
since EPA determined that only 85% reduction could be assumed in this 
case.
    Comment 3: The commenter states that EPA did not follow the two-
step process described in 40 CFR 51.301, which involves first 
identifying the best control technology for reducing NOX and 
then applying the five factors to determine the best emissions limit 
achievable by that technology. A different emission limit should be 
chosen only if the technology fails to meet one of the five factors. 
Instead, EPA provided a list of all feasible methods to remove 
NOX, ranked from least effective (worst) to most effective 
(best) based on their NOX control efficiency. In sorting 
through the ranked list of control options to pick the BART control 
technology, the EPA started at the bottom, with the worst control, and 
moved up to the best control, thus corrupting the entire process.
    Response 3: We reiterate that EPA was not conducting a BART 
determination for NOX at RGGS. Rather, we were reviewing the 
adequacy of NDEP's BART analysis. NDEP noted, correctly, that RGGS is 
not the size of a facility for which application of the BART Guidelines 
is mandatory.
    The process described in the comment is comparable to the process 
for determining Best Available Control Technology (BACT) established in 
the Prevention of Significant Deterioration regulations. The states, 
however, are not required to use a top-down BACT process for making a 
BART determination. EPA stated in its final BART rule that, ``States 
should retain the discretion to evaluate control options in whatever 
order they choose, so long as the State explains its analysis of the 
CAA factors.'' See 70 FR 39130 (July 6, 2005). NDEP's determination to 
eliminate SCR from consideration as BART was based on weighing the 
small incremental visibility improvement from SCR against its 
incremental cost-effectiveness. This decision is within the discretion 
that a state can exercise in evaluating BART because it considered the 
appropriate factors and came to a reasonable determination, especially 
in this case which was not required to meet all aspects of EPA's BART 
guidelines.
    Comment 4: The proposal does not demonstrate that a NOX 
limit of 0.05 lb/MMBtu on a 30-day rolling average basis using SCR has 
any adverse impacts when subjected to a site-specific, case-by-case, 
five-factor analysis.
    Response 4: The comment does not set forth the appropriate standard 
for a BART analysis. The process described by the commenter is 
analogous to a top-down control technology review conducted when 
determining the BACT for new major stationary sources or major 
modifications at existing stationary sources. As stated in Response 3, 
states are not required to use a top-down BACT process for making a 
BART determination, and states retain discretion to evaluate control 
options in whatever order they choose, as long as the state explains 
its analysis of the CAA factors.
    NDEP applied the five-factor BART analysis for NOX at 
RGGS. NDEP weighed the five factors and concluded that the small 
visibility improvement expected from installation of SCR did not 
justify the incremental cost of SCR. EPA independently and thoroughly 
evaluated NDEP's determination. EPA also considered both average and 
incremental cost effectiveness as well as visibility improvement. 
Although we disagree with NDEP's calculation of the cost effectiveness 
of SCR compared to SNCR, our modeling analysis has demonstrated that 
the visibility improvement from SCR is very small at GCNP. The 
visibility improvement from SCR is only 0.38 dv, and the incremental 
visibility improvement between SCR and SNCR is only 0.10 dv. The 
annualized cost of SNCR is approximately $1.02 million per unit, and 
the annualized cost of SCR is approximately $3.8 million per unit, 
making it four times as expensive as SNCR.\11\ NDEP's determination 
that NOX BART is an emissions rate that is achievable with 
SNCR is reasonable based on its weighing of the small visibility 
improvement against the cost of SCR.
---------------------------------------------------------------------------

    \11\ EPA cost estimates, as listed in Appendix B of the TSD to 
our April 4 proposed action [Appendix B--Control Cost Estimate 
Revisions (September 2011 updated estimates)].
---------------------------------------------------------------------------

    Comment 5: The statute and regulations do not require EPA to 
compare the best technology to the next best technology, and then 
reject the best technology based on incremental differences.
    Response 5: EPA was not conducting its own BART analysis but was

[[Page 50940]]

reviewing the adequacy of NDEP's BART analysis. We agree with the 
commenter that the CAA and regional haze regulations do not require the 
state to reject the best technology based on incremental differences. 
However, we note that the state has the discretion to compare the 
incremental cost-effectiveness and incremental visibility improvement 
that will result from various technologies. See 70 FR 39129 (July 6, 
2005). The state must evaluate the differences between control 
technologies reasonably and provide a justification for rejecting a 
technology. For the RGGS NOX BART determination, we are 
finalizing our approval of NDEP's elimination of SCR as BART based on 
the small visibility improvement that would result at the GCNP weighed 
against its cost-effectiveness. In addition, NDEP noted that RGGS is 
the size of a facility for which application of the BART Guidelines is 
not mandatory. Thus, EPA concluded that NDEP's NOX BART 
determination was reasonable.
    Comment 6: EPA's consideration of the incremental visibility 
improvement between SCR and SNCR is contrary to law because there is no 
incremental visibility factor.
    Response 6: We disagree with the comment that considering 
incremental visibility improvement is prohibited by the CAA or our 
regulations. The CAA and our regional haze regulations specify that the 
states or EPA must consider cost and visibility in the five-factor 
analysis. With respect to the cost factor, in promulgating the BART 
Guidelines, EPA responded to a comment stating: ``In addition, the 
guidelines continue to include both average and incremental costs. We 
continue to believe that both average and incremental costs provide 
information useful for making control determinations.'' See 70 FR 39127 
(July 6, 2005). The commenter did not cite any regulatory language that 
would preclude incremental cost effectiveness in considering the cost 
of compliance. With respect to using incremental visibility 
improvement, EPA's response to comments on promulgating the BART 
guidelines stated:

    For example, a State can use the CALPUFF model to predict 
visibility impacts from an EGU in examining the option to control 
NOX and SO2 with SCR technology and a 
scrubber, respectively. A comparison of visibility impacts might 
then be made with a modeling scenario whereby NOX is 
controlled by combustion technology. If expected visibility 
improvements are significantly different under one control scenario 
than under another, then a State may use that information, along 
with information on the other BART factors, to inform its BART 
determination. See 70 FR 39129 (July 6, 2005).

    EPA's regulations allow states to compare incremental cost-
effectiveness and visibility improvements between different 
technologies. The incremental visibility benefit is one way to compare 
the visibility improvements from various controls. For this BART 
determination, NDEP weighed the small incremental visibility 
improvement against the incremental cost effectiveness. Based on 
weighing these factors, NDEP provided a reasoned justification for 
choosing SNCR technology as NOX BART for RGGS. EPA's 
independent analysis indicates that NDEP properly exercised its 
discretion in its process for weighing the small visibility improvement 
against the cost-effectiveness to reject SCR.

C. BART Selection Criteria

    Comment 7: EPA did not provide the public with the criteria for 
making its BART determination, which appears inconsistent with the BART 
Guidelines and the intent of the Regional Haze Rule.
    Response 7: As noted previously, EPA was not conducting its own 
BART analysis. We were reviewing the adequacy of NDEP's BART analysis. 
NDEP correctly noted that RGGS is not the size of a facility for which 
application of the BART Guidelines is mandatory.
    After receiving significant comments on our initial proposed rule 
(76 FR 36450), EPA independently and thoroughly reviewed NDEP's 
NOX BART determination and concluded that NDEP provided the 
public with information regarding the criteria it was applying in 
making its BART determination. See ``Revised NDEP BART Determination 
Review of NV Energy's Reid Gardner Generating Station Units 1, 2 and 
3'' revised October 22, 2009. NDEP adequately informed the public about 
the basis for its NOX BART determination for RGGS, stating: 
``NDEP concluded, based on a review of the economic analysis, that the 
$/ton of NOX removed increased significantly for the LNB 
with OFA and SNCR, and ROFA with SCR technologies without 
correspondingly significant improvements in visibility.'' Id. page 6. 
We are approving NDEP's determination that NOX BART for RGGS 
is an emissions rate that is achievable by installing and operating LNB 
with OFA and SNCR because NDEP reasonably weighed the small incremental 
visibility improvement that would result from installation of SCR 
against its higher cost. NDEP adequately disclosed the factors it 
considered in its BART determination.
    Comment 8: EPA fails to explain what level of incremental cost or 
visibility improvement would justify SCR. EPA should disclose the 
dollar limit and rationale for what constitutes ``cost effectiveness,'' 
and how its method is consistently applied across other facilities and 
states.
    Response 8: EPA's approval of NDEP's BART determination is based on 
finding that the State adequately considered the appropriate factors 
for BART and provided a reasonable explanation for selecting a 
NOX emissions rate that can be achieved with SNCR. NDEP 
explained that requiring SCR technology would result in a small 
incremental visibility improvement over SNCR when weighed against the 
incremental cost-effectiveness of SCR. As stated in our proposed 
approval, our modeling analysis was performed ``in a manner that more 
closely adheres with current EPA regulatory guidance on CALPUFF 
modeling.'' See 77 FR 21903 (April 12, 2012). Our analysis found that 
the average and incremental visibility improvement would be 
significantly lower than the visibility improvement relied upon by 
NDEP. In addition, EPA's revised cost analysis also indicated lower 
cost per ton of pollutant removed for SCR. In our analysis, we 
evaluated the cost-effectiveness of both technologies (SCR and SNCR 
with LNB and OFA) based on using the Control Cost Manual (CCM) for 
including appropriate costs.
    Our modeling shows that there would be a very small improvement in 
visibility at the GCNP from using SCR at RGGS. Based on this analysis 
we have determined that we can approve NDEP's determination that RGGS 
is required to comply with a NOX emissions rate that can be 
achieved with SNCR as BART. Although the values that EPA considered for 
cost-effectiveness and visibility improvement differ from NDEP's 
analysis, we conclude NDEP's analysis reasonably weighed the small 
visibility improvement against the cost to eliminate SCR.
    One comment faults EPA, stating: ``EPA further fails to explain 
what level of incremental cost or visibility improvement would justify 
the incremental cost.'' See Consortium Letter at page 6. EPA's BART 
guidelines did not establish bright-line thresholds for cost-
effectiveness or visibility improvement, choosing to allow the states 
to exercise discretion to choose such values when appropriate. EPA 
stated:

[[Page 50941]]

    We agree with the suggestion that the use of a comparison 
threshold, as is done for determining if BART-eligible sources 
should be subject to a BART determination, is an appropriate way to 
evaluate visibility improvement. However, we believe the States have 
flexibility in setting absolute thresholds, target levels of 
improvement, or de minimis levels since the deciview improvement 
must be weighed among the five factors, and States are free to 
determine the weight and significance to be assigned to each factor. 
For example, a 0.3, 0.5 or even 1.0 deciview improvement may merit 
stronger weighting in one case versus another, so one `bright line' 
may not be appropriate. See 70 FR 39129 (July 6, 2005).

    The same rationale should apply to cost-effectiveness. A bright 
line for cost-effectiveness may not be appropriate for every case and 
is dependent on case specific factors relating to economics and 
technology. In this case-by-case determination, the small amount of 
visibility improvement did not justify the cost of SCR.
    Comment 9: EPA should explain the amount of incremental visibility 
improvement from SNCR to SCR that would justify the incremental cost 
increase of SCR, since no threshold is established in rulemaking or 
guidance.
    Response 9: EPA is not setting generally applicable thresholds for 
incremental cost-effectiveness or visibility improvement for the 
reasons discussed above. EPA's BART Guidelines established presumptive 
emissions limits for SO2 and NOX at electric 
generating units at facilities generating more than 750 MW. But EPA did 
not extend those presumptive emissions limits to electric generating 
units at smaller facilities, such as RGGS.
    EPA did not establish presumptive cost-effectiveness or visibility 
improvement values. EPA left weighing the factors to the state 
providing the state considered the five factors and exercised its 
discretion reasonably. Here, EPA proposed to find that NDEP reasonably 
eliminated SCR when it weighed the cost-effectiveness against the small 
incremental visibility improvement associated with requiring SCR rather 
than SNCR.
    BART is a case-by-case analysis that is initially evaluated by the 
states. Provided the state exercises its discretion reasonably and 
meets the requirements of the CAA and regulations, EPA may approve it. 
EPA's approval is not a ministerial act. In this rulemaking, EPA has 
carefully reviewed the basis for NDEP's determination. There is no 
reason, and none is provided in the comment, to support the assertion 
that EPA should establish thresholds for cost-effectiveness or 
visibility improvement, or challenge EPA's authority to approve a BART 
determination without them.
    Comment 10: EPA's use of incremental visibility improvement to find 
that the cost of SCR is unjustified contradicts its finding that SCR is 
cost-effective (77 FR 21901).
    Response 10: The commenter mischaracterizes EPA's proposed 
approval. The commenter is correct that we did not find the average and 
incremental cost-effectiveness of SCR to be cost prohibitive. 
Nevertheless, our evaluation supported NDEP's determination that the 
small amount of visibility improvement at GCNP did not justify the cost 
of SCR.
    The comment states that EPA has invented a ``sixth factor'' by 
``concatenating incremental visibility and incremental cost.'' See 
Consortium Letter, page 7. EPA has not invented an additional factor in 
the BART analysis but has approved a reasonable conclusion reached by 
NDEP when it weighed these two factors. NDEP's weighing two factors in 
the analysis does not create a sixth factor. The comment does not 
explain how weighing two factors in the five-factor analysis 
constitutes stringing together and joining those factors into a sixth 
factor.
    National Parks Conservation Association and Sierra Club wrote to 
EPA on June 29, 2012, concerning several regional haze actions. We are 
treating this letter as a late comment on our proposed action and 
including it in our docket as such. This letter indicates that NPCA and 
Sierra Club understand that our approval is based on finding that NDEP 
reasonably weighed visibility improvement and cost-effectiveness rather 
than inventing an additional BART factor. The letter provides:

    In many cases, EPA has summarily concluded that the incremental 
costs of concededly superior controls are not warranted by the 
visibility benefits determinations, which are routinely at odds with 
the Agency's own analysis demonstrating that installing the most 
effective controls will yield needed visibility improvements. See 
Letter dated June 29, 2012, page 1.

    EPA's analyses are also based on weighing the five BART factors. 
The relative weight of the cost-effectiveness and visibility 
improvement varies depending on the facility at issue. For the three 
100 megawatt units at RGGS, EPA concludes that notwithstanding 
differing conclusions about both cost and visibility improvement, NDEP 
reasonably determined that a small visibility improvement at GCNP does 
not justify the cost of SCR. Our approval of NDEP's NOX BART 
determination on this basis is consistent with our actions on other 
regional haze SIPs. See, e.g., 77 FR 24385 (Apr. 24, 2012) (Final 
Approval of Maine SIP).

 D. Cost Analysis

    Comment 11: The incremental cost difference between SCR and SNCR is 
less than EPA estimated because the cost of SCR is overestimated and 
the cost of SNCR is underestimated, making SCR look relatively more 
expensive than is the case.
    Response 11: The comment does not provide any basis for EPA to 
revise its proposed approval of NDEP's NOX BART 
determination. Our proposal stated:

    Based on our revised cost estimates, we do not consider these 
[EPA's] average and incremental cost effectiveness values for SCR 
and LNB and OFA as cost prohibitive. Our analysis of this factor 
indicates that costs of compliance (average and incremental) are not 
sufficiently large to warrant eliminating SCR from consideration. 
The incremental cost effectiveness values for Units 1 and 2 are 
around $4,500/ton. Although EPA does not consider this incremental 
cost prohibitive, we note that the State has certain discretion in 
weighing this cost. Because RGGS is not a facility over 750 MW and 
therefore not subject to EPA's presumptive BART limits, the State 
may exercise its discretion more broadly in this particular 
determination. See 77 FR 21901 (April 12, 2012).

    Even if the average and incremental cost-effectiveness between SCR 
and SNCR were somewhat different, NDEP's BART determination would still 
be approvable based on its reasonable weighing of the cost and 
visibility improvement factors.
    Comment 12: EPA incorrectly estimated the cost-effectiveness of SCR 
(i.e., dollars per ton of emissions removed on an annual basis) by 
assuming that SCR can achieve an annual average emission no lower than 
0.083 to 0.098 lb/MMBtu, despite substantial evidence that SCR can 
achieve 0.05 lb/MMBtu or lower on an annual basis.
    Response 12: EPA disagrees with this comment. Regarding the 
accuracy of the cost effectiveness calculations of SCR, the commenter 
is correct that we estimated cost-effectiveness of SCR based on annual 
average emission rates ranging from 0.083 to 0.098 lb/MMBtu. However, 
we indicated in our proposal that we did not find SCR to be cost 
prohibitive at these emission rates. As a result, although we did 
consider more stringent SCR emission rates, such as 0.06 lb/MMBtu, when 
evaluating visibility improvement, we did not also revise our cost 
estimates to reflect the more stringent SCR emission rates, since we 
had already indicated that did not

[[Page 50942]]

find SCR to be cost prohibitive at the less stringent SCR emission 
rates. It would not have been in any way determinative to our decision 
to find that SCR was ``even more'' cost-effective or that the 
incremental cost-effectiveness value between SCR and SNCR was ``even 
more'' incrementally cost-effective.
    Regarding the emission rate achievable by SCR, the BART Guidelines 
state that: ``[i]n assessing the capability of the control alternative, 
latitude exists to consider special circumstances pertinent to the 
specific source under review, or regarding the prior application of the 
control alternative'' (70 FR 39166, July 6, 2005).\12\ In other words, 
the BART emission limits are not required to represent the maximum 
level of control ever achieved by a given technology. Limits set as 
BACT under the PSD program, or emission rates achieved from the 
operation of individual facilities under an emission trading program 
(e.g., Clean Air Interstate Rule), may provide important information, 
but should not be construed to automatically represent the most 
appropriate BART limit for all facilities.
---------------------------------------------------------------------------

    \12\ Although NDEP's BART analysis for RGGS need not conform to 
the BART guidelines because the capacity of RGGS is smaller than 750 
MW, the BART guidelines do provide useful guidance in setting 
appropriate BART limits.
---------------------------------------------------------------------------

    The coal composition is also an important component of estimating 
the NOX emissions rate that a facility can achieve. RGGS is 
capable of purchasing coal on the spot market so there is likely to be 
variability in the NOX emissions rate that would be 
achievable with SCR or SNCR. As previously discussed in the response to 
Comment 2, RGGS receives its coal by rail line and has access to 
different ranked coals with varying nitrogen content, which influence 
the NOX concentration in the exhaust going to either SNCR or 
SCR controls. EPA's policy is to set an emission limit that would 
reasonably accommodate the various coal sources under these 
circumstances.
    EPA disagrees with this comment, but even if we accepted the 
premise that RGGS is capable of continuously meeting an emission limit 
of 0.05 lb/MMBtu, the comment does not provide any basis for EPA to 
change our approval of NDEP's SIP or our FIP. Assuming the cost of 
achieving 0.05 lb/MMBtu was equal to the cost of achieving 0.083 to 
0.098 lb/MMBtu, using a NOX emissions rate of 0.05 lb/MMBtu 
for SCR would likely result in lower average and incremental cost per 
ton values. Thus, we would calculate SCR to be more cost-effective 
(i.e., lower dollars per ton) on an average and incremental basis. As 
stated above, EPA did not determine the average or incremental cost of 
SCR to be prohibitive. Rather, EPA's approval of NDEP's determination 
that NOX BART for RGGS for Units 1 and 2 is an emissions 
limit of 0.20 lb/MMBtu that can be achieved by installing and operating 
LNB with OFA and SNCR is based on our determination that NDEP 
reasonably weighed the visibility improvement against the other factors 
in rejecting SCR. EPA does not believe this analysis would be 
significantly altered by slightly lower incremental cost numbers.
    Comment 13: EPA did not correct all the errors in the State's cost 
calculations for SCR (e.g., lack of multiple unit discounts, high 
reagent costs, incorrect capital recovery factor), which would have 
further reduced the cost and improved the cost effectiveness of SCR, 
thereby reducing the incremental cost difference with SNCR.
    Response 13: EPA partially agrees with this comment. EPA's revised 
cost-effectiveness values are consistent with EPA's regulations and the 
parameters set forth in the CCM. EPA explained in promulgating the BART 
Guidelines that ``[s]tates have flexibility in how they calculate 
costs.'' See 70 FR at 39127 (July 6, 2005). A state may deviate from 
the Control Cost Manual provided its analysis is reasonable. EPA 
independently evaluated NDEP's cost-effectiveness calculation, stating 
in our proposal:

    We received several public comments that NDEP's cost 
calculations were overestimated and based on methodology 
inconsistent with EPA's Control Cost Manual (CCM). [footnote 
omitted]. We agree that NDEP included inappropriate costs and our 
analysis excludes those costs that are not allowed by the CCM. See 
77 FR 21901 (April 12, 2012).

    Our proposal noted that we did not revise the cost-effectiveness 
calculation to adjust for all of the discrepancies with the CCM because 
based on our initial adjustments we found that SCR was not cost-
prohibitive. It would not have been in any way determinative to our 
decision to find that SCR was ``even more'' cost-effective or that the 
incremental cost-effectiveness value between SCR and SNCR was ``even 
more'' incrementally cost-effective.
    As discussed above, EPA is approving NDEP's determination that 
NOX BART is an emissions limit achievable with SNCR rather 
than SCR. The basis for our approval is that when NDEP weighed the 
small visibility improvement of moving from an emissions limit 
achievable with SNCR to one based on SCR against the incremental cost-
effectiveness of SCR, NDEP determined that NOX BART for RGGS 
for Units 1 and 2 is an emissions limit of 0.20 lb/MMBtu that can be 
achieved by installing and operating LNB with OFA and SNCR. NDEP has 
discretion in determining how to weigh the factors in reaching a BART 
decision under the CAA and regional haze regulations. NDEP's rationale 
for its decision, although based on different values than EPA 
calculated and modeled, was reasonable. Therefore, EPA is approving 
NDEP's determination.
    The comment implies that correcting each of the costs listed as 
incorrect and substituting a SCR emissions limit of 0.05 lb/MMBtu 
rather than 0.06 lb/MMBtu for SCR would yield a very low incremental 
cost difference between SCR and SNCR. However, that implication is not 
supported by the comment. The comment does not calculate an alternative 
average or incremental cost-effectiveness differential between SCR and 
SNCR. Therefore, EPA is approving NDEP's conclusion that the 
incremental cost-effectiveness is not justified when weighed against 
the small visibility improvement.
    Comment 14: EPA did not consider the adverse non-air quality 
impacts of SNCR due to ammonia injection, which would increase the cost 
of SNCR and reduce the incremental cost difference with SCR.
    Response 14: As noted previously, EPA was reviewing the State's 
BART determination to evaluate whether NDEP reasonably applied the 
requirements of the CAA and the regional haze regulations. EPA 
anticipates that ammonia emissions will be quite low because these 
units are equipped with baghouses and wet scrubbers that each can be 
expected to remove most ammonia slip associated with SNCR or SCR. To 
the extent the commenter is concerned that considering costs due to 
ammonia injection would lower the incremental cost-effectiveness value 
between SCR and SNCR, EPA reiterates that our proposed approval of 
NDEP's RGGS NOX BART determination is not based on agreeing 
with NDEP that SCR is not cost-effective. EPA's proposed approval 
states that SCR is cost-effective. Nonetheless, the BART determination 
is a multiple-factor analysis. NDEP has discretion to determine how to 
weigh the factors. Our independent analysis of the two critical factors 
demonstrated that the NDEP reasonably weighed the cost of SCR controls 
against the small visibility improvement to determine that SNCR is 
NOX BART for RGGS.

[[Page 50943]]

    Comment 15: In determining the average and incremental cost-
effectiveness, EPA should have used actual emissions for the baseline 
value of each unit rather than each unit's annualized maximum permitted 
heat input multiplied by each unit's maximum permitted NOX 
limit, which is closer to the potential to emit (PTE).
    Response 15: EPA disagrees with this comment. Again, we note that 
EPA was not performing its own BART analysis, but was reviewing the 
adequacy of NDEP's BART analysis. The commenter is correct in noting 
that, in our review of NDEP's evaluation of the cost of compliance, we 
did not modify the estimate of baseline annual emissions that NDEP used 
in its cost calculations. We agree that NDEP's baseline more closely 
represents the sources' PTE, and results in higher baseline annual 
emissions than the methodology proposed by the commenter, which would 
rely almost entirely on past actual annual emissions. Because the 
regional haze regulations and BART Guidelines are not prescriptive 
regarding the calculation of baseline emissions, stating that ``the 
baseline emissions rate should represent a realistic depiction of 
anticipated annual emissions for the source'' \13\, the commenter's 
proposed methodology is a potentially acceptable way to calculate 
baseline annual emissions. NDEP used a methodology that resulted in a 
higher estimate of baseline annual emissions, and we consider the 
methodology used by NDEP to be within the discretion afforded to 
states.
---------------------------------------------------------------------------

    \13\ 70 FR 39167, July 6, 2005.
---------------------------------------------------------------------------

 E. Cost of Compliance

    Comment 16: Use of EPA's Air Pollution Control Cost Manual 
(``CCM'') is not required since RGGS is less than a 750 megawatt 
facility.
    Response 16: EPA agrees that the states are not required to use the 
CCM for electric generating units smaller than 750 MW but that it is 
generally a good guide concerning costs to include and exclude. EPA 
performed an independent average and incremental cost-effectiveness 
calculation using the CCM to evaluate whether NDEP had reasonably 
weighed small visibility improvements against the incremental cost-
effectiveness of requiring SCR rather than SNCR. EPA's analysis 
resulted in different cost-effectiveness and visibility improvement 
values. Although the values for these factors differed from NDEP's 
values, our analysis supported approving NDEP's NOX BART 
determination to establish an emissions limit of 0.20 lb/MMBtu 
achievable from installing and operating SNCR.
    Comment 17: EPA's Air Pollution Control Cost Manual is out of date, 
and thus substantially underestimates current market costs of control 
technologies including SCR, which misrepresents the cost-effectiveness 
of chosen technologies.
    Response 17: EPA disagrees with the comment. The CCM is a valuable 
resource to guide the states in evaluating costs that should be 
included or excluded. The states have discretion to rely on specific 
capital and annual cost information that is updated or specific to the 
facility under consideration.

 F. Visibility Analysis

    Comment 18: EPA underestimated the visibility improvement that 
would result from SCR by assuming an emissions limit of 0.06 lb/MMBtu 
(about 84 percent efficiency) instead of 0.05 lbs/MMBtu (about 90 
percent efficiency) or lower, which was achieved at 21 coal-fired EGUs 
in 2011, 11 of which are dry-bottom, wall-fired units like RGGS.
    Response 18: EPA disagrees with this comment. As noted previously, 
the purpose of EPA's independent analyses assessing anticipated 
visibility improvements and cost-effectiveness of SCR were to evaluate 
the reasonableness of NDEP's determination based on weighing small 
incremental visibility improvement against the incremental cost-
effectiveness of SCR. The modeling that NDEP relied on assumed that SCR 
would reduce NOX between 78 percent and 82 percent. Although 
NDEP's assumptions for SCR performance were within the range of 
emission rates achieved nationwide, EPA determined that for the 
purposes of visibility modeling and calculating cost-effectiveness of 
SCR, assuming an 85 percent reduction efficiency to meet an emissions 
limit of 0.06 lb/MMBtu was reasonable for RGGS. As noted by the 
commenter, other coal-fired facilities do achieve emission rates of 
0.05 lb/MMBtu or lower, and some BART determinations have established a 
NOX emission limit of 0.05 lb/MMBtu for SCR. However, as 
noted in Response 12, emissions information reported to EPA's Clean Air 
Markets program show that among coal-fired boilers operating with SCR 
nationwide, there is significant variability in actual NOX 
emission rates achieved, ranging from below 0.05 to greater than 0.10 
lb/MMBtu.
    EPA's assumption that RGGS could meet an emission limit of 0.06 lb/
MMBtu is reasonable and within the expected performance range of SCR. 
The commenter does not provide a basis, e.g., modeling that compares 
visibility benefits expected from a NOX limit of 0.05 versus 
0.06 lb/MMBtu, to change our approval of NDEP's determination that 
NOX BART for RGGS is an emissions limit of 0.20 lb/MMBtu 
that can be achieved by installing and operating LNB with OFA and SNCR 
for the three units at RGGS. EPA anticipates that even if we modeled 
SCR to achieve 0.05 lb/MMBtu instead of 0.06 lb/MMBtu, the visibility 
benefits of SCR would still be smaller than the benefits modeled by 
NDEP. For example, if the post-SCR impact at GCNP is scaled by 0.05/
0.06, it decreases from 0.20 dv to 0.17 dv. Relative to the 0.59 dv 
base case impact, the benefit of SCR would correspondingly increase 
from 0.38 dv to 0.42 dv, roughly 10 percent higher. However, as 
discussed in the Technical Support Document (``TSD'') for our proposed 
rule, EPA's estimates of visibility impacts are more than 50 percent 
lower than those relied on by NDEP due to differences in modeling 
procedures. The net effect of using 0.05 lb/MMBtu as the NOX 
emissions factor would not change the fact that EPA's estimate of SCR's 
benefit would remain substantially smaller than that estimated by NDEP. 
As noted in previous responses, NDEP determined that the visibility 
benefits of SCR based on its modeling do not justify the cost. Thus, 
additional modeling of SCR at a lower emission rate is not likely to 
change NDEP's consideration of the visibility factor, or our 
determination that NDEP's process for weighing the factors is 
reasonable.
    Comment 19: The small visibility improvement from SCR is the result 
of underestimating the base case emissions and the amount of 
NOX that could be removed by SCR. The commenter provided an 
alternative, larger estimate of SCR benefits by scaling the EPA 
modeling results.
    Response 19: EPA disagrees with this comment. EPA performed an 
independent modeling analysis to ensure NDEP's NOX BART 
determination was reasonable. Although estimates of the visibility 
improvement would be larger if EPA had used higher base case emissions, 
the scaling method used by the commenter does not accurately reflect 
the effect of a different base case, which would require new modeling. 
Even if the commenter's scaling method results were accurate, the 
estimated visibility improvement remains small. The scaled benefits of 
SCR provided by the commenter are 0.7 dv at GCNP, and 1.9 dv 
cumulatively over the five Class I areas; the comparable scaled figures 
for SNCR would be 0.4 dv and 1.1 dv

[[Page 50944]]

cumulatively. Thus, using the commenter's method, the incremental 
visibility improvement of SCR over SNCR would be 0.3 and 0.8 
cumulatively. This is only slightly larger than the EPA-estimated 
benefit increase of 0.2 dv at GCNP, and is the same as the EPA-
estimated benefit increase of 0.8 dv cumulatively. EPA's decision to 
approve NDEP's BART determination would be unchanged. See also the 
response to comment 20.
    Comment 20: A commenter states that EPA used NDEP's NOX 
baseline emission rates and control scenario emission rates to 
determine modeled visibility impacts. Because NDEP's emission rates are 
based on an annual average instead of a maximum 24-hr average, the 
commenter alleges that EPA underestimated visibility impacts, and 
provides its own estimate of 24-hr average baseline and control 
scenario emission rates.
    Response 20: We acknowledge that we used NDEP's baseline and 
control scenario emission rates, based on annual average emission 
factors, in the visibility modeling supporting our proposed approval. 
As noted in our proposal, NDEP modified the baseline emission rates and 
control scenario emission rates that Nevada Energy included in the BART 
analysis.\14\ NDEP did not, however, perform updated modeling to 
determine the visibility improvement associated with the revised 
baseline emission rates and revised control scenario emission rates. 
The absence of modeling results complicated our ability to evaluate the 
adequacy of NDEP's analysis. To evaluate the adequacy of NDEP's 
analysis, we performed our visibility modeling using NDEP's revised 
baseline and revised control scenario emission rates. Again, the 
purpose of our modeling was to evaluate the adequacy of NDEP's analysis 
which is not directly comparable to any modeling decisions we might 
make in our own BART determination as part of a FIP, such as at San 
Juan Generating Station.
---------------------------------------------------------------------------

    \14\ 77 FR 21903.
---------------------------------------------------------------------------

    Regarding the use of control scenario emission rates based upon 
annual average emission factors (in lb/MMBtu) instead of 24-hour 
average emission factors (lb/MMBtu), we disagree with the commenter 
that these emission rates do not provide acceptable estimates of 
visibility benefits. The methodology for calculating control scenario 
model emission rates described by the commenter involves applying the 
estimated control efficiencies of a particular technology to the 
baseline (pre-control) model emission rate. While this methodology has 
been used by EPA, it does not preclude the use of other methodologies 
for calculating control scenario emissions. In the case of control 
technology performance, engineering estimates of a particular 
technology's post-control level of performance will often be expressed 
in terms of lb/MMBtu, either on a 30-day or annual average basis. To 
the extent that the engineering estimate represents a more accurate 
depiction of future anticipated emissions at a particular facility, it 
may be appropriate to rely on the specified post-control level of 
performance rather than on a control efficiency applied to a pre-
control emission rate. In fact, using model emission rates based on an 
annual average, instead of a 24-hour average, results in more stringent 
emission rates. As an example, the RGGS Unit 1 model emission rate 
calculated by the commenter for SCR and LNB with OFA is 99 lb/hr.\15\ 
By comparison, the RGGS Unit 1 model emission rate used by EPA for this 
same technology is 73 lb/hr.\16\
---------------------------------------------------------------------------

    \15\ See Table 13, National Park Service comment letter dated 
June 4, 2012, from Susan Johnson (NPS) to Thomas Webb (EPA).
    \16\ As used in Model Scenario c16 that is based on the more 
stringent level of SCR+LNB+OFA performance of 0.06 lb/MMBtu. See 
Technical Support Document, Appendix C, Docket Item No. EPA-R09-
2010-0130-0077-11 and -15.
---------------------------------------------------------------------------

    Regarding the use of baseline emission rates based upon the annual 
average maximum instead of the 24-hour average maximum, we agree with 
the commenter that the BART guidelines state: ``Use the 24-hour average 
actual emission rate from the highest emitting day of the 
meteorological period modeled (for the pre-control scenario).'' See 70 
FR 39170 (July 6, 2005). We note, however, that because the capacity of 
RGGS is less than 750 MW, NDEP is not required to adhere to the BART 
guidelines, and is therefore afforded some flexibility when evaluating 
the five statutory factors in its analysis of RGGS. We disagree that 
the maximum 24-hour average baseline emissions the commenter provided 
are representative of RGGS' historical performance.\17\ The baseline 
emissions provided by the commenter include a period of malfunction 
extending from January 8, 2003 to March 27, 2003. The result is maximum 
24-hour average values that overstate RGGS' emission rate, and would 
therefore also overstate its visibility impact. If examining baseline 
emissions on a 24-hour average basis, we consider the WRAP 
NOX emission rates indicated by the commenter to be more 
representative of maximum 24-hr average emissions,\18\ and note that 
these emission rates were included in our modeling analysis as Scenario 
c02.
---------------------------------------------------------------------------

    \17\ Column 2 in Tables 11, 13, 15, National Park Service 
comment letter dated June 4, 2012, from Susan Johnson (NPS) to 
Thomas Webb (EPA).
    \18\ Column 6, Table 11, ibid.
---------------------------------------------------------------------------

    The commenter also provides scaled estimates of visibility benefit 
based upon its estimates of 24-hour average baseline and control 
scenario emission rates. Notwithstanding our disagreements with the 
commenter noted above, if we use the WRAP's maximum 24-hour average 
emission rate as the baseline instead of the NDEP baseline, and scale 
our control scenario visibility benefits accordingly, we estimate the 
following visibility improvement at Grand Canyon National Park: \19\
---------------------------------------------------------------------------

    \19\ Based on Visibility Method 8, best 20 percent days 
background, as summarized in Appendix E of the TSD from our April 4, 
2012 proposed action. [Appendix E--RGGS--TSD--CALPUFF--tables.xls]

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Original                                         Scaled
                                                         -----------------------------------------------------------------------------------------------
                                                                              Visibility improvement                          Visibility improvement
                        Scenario                            Visibility   --------------------------------   Visability   -------------------------------
                                                              impact        Total (from     Incremental       impact        Total (from     Incremental
                                                                             baseline)      (from prev)                      baseline)      (from prev)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                dv                      dv                      dv                      dv
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline NOX LNB+OFA....................................            0.59  ..............  ..............            0.74  ..............  ..............
Enh. LNB+OFA............................................            0.51           -0.08           -0.08            0.64           -0.10           -0.10
SNCR+LNB+OFA............................................            0.37           -0.21           -0.13            0.47           -0.27           -0.17
ROFA+Rotamix............................................            0.31           -0.28           -0.06            0.39           -0.35           -0.08
SCR+LNB+OFA.............................................            0.22           -0.36           -0.09            0.28           -0.46           -0.11

[[Page 50945]]

 
SCR+LNB+OFA (0.06 lb/MMBtu).............................            0.20           -0.38           -0.10            0.26           -0.48           -0.13
--------------------------------------------------------------------------------------------------------------------------------------------------------

    As seen above, the scaled incremental visibility benefit of SCR (at 
0.06 lb/MMBtu) compared to the next most stringent technology, ROFA w/
Rotamix, is 0.13 deciviews, whereas the original EPA-estimated 
incremental visibility benefit is 0.10. This magnitude of incremental 
visibility benefit is still sufficiently small to justify approval of 
NDEP's analysis.

G. Cumulative Visibility Benefit Analysis

    We are providing a consolidated response to the following comments.
    Comment 21: EPA based its BART determination on the visibility 
benefits of SCR at a single Class I area that has the maximum 
visibility impact, but should have considered cumulative impacts.
    Comment 22: EPA did not consider the cumulative visibility benefits 
of SCR at all five Class I areas within 300 kilometers that are 
impacted by NOX emissions from RGGS, in contrast to 
performing a cumulative visibility benefit analysis for Four Corners 
Power Plant and Navajo Generating Station.
    Comment 23: EPA modeled the cumulative benefits of various BART 
controls across all five Class I areas as indicated in Appendix E, but 
did not include its cumulative modeling results in its proposed rule or 
TSD.
    Comment 24: EPA's modeling results for SCR at all five parks in 
Appendix E showed a cumulative visibility benefit of 1.07 dv to 1.15 
dv, which is significantly greater than the 0.38 dv benefits at GCNP 
alone.
    Comment 25: NPS calculates that the cumulative visibility benefits 
at five class I areas is about 2.0 dv for SCR on all three units.
    Response 21-25: Although EPA did not provide the cumulative sum of 
visibility impacts over the five nearby Class I areas in the Notice of 
Proposed Rulemaking, EPA did in fact take into account the impacts at 
all those areas, considering both the number of areas affected and the 
impacts and benefits occurring there. EPA provided the modeled 
visibility impacts and benefits at all five Class I areas in Appendix E 
of the Technical Support Document. We did not rely on the specific 
metric advocated by the commenters, i.e. the sum of benefits over the 
areas, but we did consider the estimated visibility impacts across all 
five Class I areas in evaluating the reasonableness of Nevada's BART 
determination. Given the magnitude of the impacts at these areas, 
however, we focused largely on the benefits at GCNP in our proposed 
action and placed little weight on the benefits at the remaining four 
Class I areas. The commenters note that the sum of the visibility 
benefits across all five impacted Class I areas from requiring SCR is 
just over 1 dv of improvement. However, as that improvement is spread 
out over five Class I areas, we do not consider this sufficient reason 
to reject the State's BART determination, especially in light of the 
incremental benefits of SCR. On a Class I by Class I basis, there would 
be little improvement in visibility from requiring SCR.
    The comment is correct that EPA provided information about the 
cumulative visibility improvement modeled for different BART scenarios 
in our Advanced Notice of Proposed Rulemaking for the Four Corners 
Power Plant and the Navajo Generating Station. EPA also provided 
information about the cumulative visibility improvement in our proposed 
and supplemental BART actions for Four Corners Power Plant. As we 
stated in those notices, EPA primarily relied on the benefits at the 
area with the greatest visibility improvement from controls, but we 
also considered impacts and benefits at nearby areas, including 
cumulative visibility benefits. EPA agrees that cumulative visibility 
benefits summed over multiple Class I areas may be a useful metric that 
can further inform a BART determination. Such an approach can be 
useful, for example, in simplifying a complex array of visibility 
impacts, especially where a source has significant impacts on multiple 
Class I areas. This approach, however, is not the only means of 
assessing visibility benefits over multiple Class I areas.
    In this action we are evaluating whether NDEP's BART determination 
for RGGS resulted in the appropriate level of control for that 
facility. EPA's independent analysis of the modeled visibility 
improvements at GCNP and all other impacted areas corroborated the 
results of the NDEP analysis.
    Comment 26: Using the WRAP baseline (scenario 00) and EPA's 
emissions limit of 0.06 lb/MMBtu (scenario 16) for SCR produces a 
cumulative visibility benefit of 1.82 dv.
    Response 26: We disagree with the commenter's use of the WRAP 
scenario 00 as the baseline against which to measure visibility 
improvement. Although Scenario 00 models the WRAP NOX 
emission rate, it also models the WRAP PM10 and 
SO2 emission rates, which correspond to emission rates prior 
to installation of fabric filters (NDEP's PM10 BART 
determination) and wet flue gas desulfurization upgrades (NDEP's 
SO2 BART determination). Scenario 16 models PM10 
and SO2 emission rates that account for the emission 
reductions associated with these control technologies. As a result, a 
comparison of Scenario 00 and 16 overestimates the benefit from SCR, 
because it also includes the visibility improvement associated with 
PM10 and SO2 emission reductions.

 H. CALPUFF Model

    Comment 27: EPA's accepted version of the CALPUFF model, introduced 
in 2007, is out of date given that new versions were updated in 2008, 
2010, and 2011.
    Response 27: EPA disagrees with the commenters that any new CALPUFF 
version should be used for the BART determination. EPA relied on 
version 5.8 of CALPUFF because it is the EPA-approved version in 
accordance with the Guideline on Air Quality Models (``GAQM'', 40 CFR 
51, Appendix W, section 6.2.1.e); EPA updated the specific version to 
be used for regulatory purposes on June 29, 2007, including minor 
revisions as of that date; the approved CALPUFF modeling system 
includes CALPUFF version 5.8, level 070623, and CALMET version 5.8 
level 070623. CALPUFF version 5.8 has been thoroughly tested and 
evaluated, and has been shown to perform consistently with the initial 
2003 version in the analytical situations for which CALPUFF has been 
approved. Any other version would be considered an ``alternative 
model'', subject to the provisions of GAQM section 3.2.2(b), requiring 
full model documentation, peer-review, and performance

[[Page 50946]]

evaluation. No such information for the later CALPUFF versions that 
meet the requirements of section 3.2.2(b) has been submitted to or 
approved by EPA. Experience has shown that when the full evaluation 
procedure is not followed, errors that are not immediately apparent can 
be introduced along with new model features. For example, changes 
introduced to CALMET to improve simulation of over-water convective 
mixing heights caused their periodic collapse to zero, even over land, 
so that CALPUFF concentration estimates were no longer reliable.\20\
---------------------------------------------------------------------------

    \20\ ``CALPUFF Regulatory Update'' Roger W. Brode, Presentation 
at Regional/State/LocalModelers Workshop, June 10-12, 2008, 
available at http://www.cleanairinfo.com/regionalstatelocalmodelingworkshop/archive/2008/agenda.htm.
---------------------------------------------------------------------------

    In addition, the latest version of CALPUFF, 6.4, incorporates a 
detailed treatment of chemistry. EPA's promulgation of CALPUFF (68 FR 
18440, April 15, 2003) as a ``preferred'' model approved it for use in 
analyses of Prevention of Significant Deterioration increment 
consumption and for complex wind situations, neither of which involve 
chemical transformations. For visibility impact analyses, which do 
involve chemical transformations, CALPUFF is considered a ``screening'' 
model, rather than a ``preferred'' model; this ``screening'' status is 
also described in the preamble to the BART Guidelines (70 FR 39123, 
July 6, 2005). The change to CALPUFF 6.4 is not a simple model update 
to address bug fixes, but a significant change in the model science 
that requires its own rulemaking with public notice and comment.
    Furthermore, it should be noted that the U.S. Forest Service and 
EPA review \21\ of CALPUFF version 6.4 results for a limited set of 
BART applications showed that differences in its results from those of 
version 5.8 are driven by two input assumptions and not associated with 
the chemistry changes in 6.4. Use of the so-called ``full'' ammonia 
limiting method and finer horizontal grid resolution are the primary 
drivers in the predicted differences in modeled visibility impacts 
between the model versions. These input assumptions have been 
previously reviewed by EPA and the FLMs and have been rejected based on 
lack of documentation, inadequate peer review, and lack of technical 
justification and validation.
---------------------------------------------------------------------------

    \21\ ``CALPUFF Status and Update'' Tyler J. Fox, Presentation at 
Regional/State/LocalModelers Workshop, April 30-May 4, 2012, 
available at http://www.cleanairinfo.com/regionalstatelocalmodelingworkshop/archive/2012/agenda.htm.
---------------------------------------------------------------------------

    EPA intends to conduct a comprehensive evaluation of the latest 
CALPUFF version along with other ``chemistry'' air quality models in 
consultation with the Federal Land Managers, including a full 
statistical performance evaluation, verification of its scientific 
basis, determination of whether the underlying science has been 
incorporated into the modeling system correctly, and evaluation of the 
effect on the regulatory framework for its use, including in New Source 
Review permitting. CALPUFF version 5.8 has already gone through this 
comprehensive evaluation process and remains the EPA-approved version, 
and is thus the appropriate version for EPA's corroboration of NDEP's 
BART determination.

 I. Nitrate Contribution to GCNP

    We are providing a consolidated response to the following comments.
    Comment 28: The WRAP's modeling supports the fact that 
NOX is only a small contributor to visibility impairment at 
GCNP.
    Comment 29: NOX is mostly from cars and is not a major 
contributor to haze compared to other pollutants.
    Comment 30: The contribution of nitrates from RGGS to haze at GCNP 
is so insignificant (0.01 percent) that any additional visibility 
benefit associated with SCR controls would yield an imperceptible 
improvement at GCNP for a significantly greater cost.
    Comment 31: EPA's modeling did not take into account the fact that 
nearly 25,000 tons per year of NOX has been eliminated from 
the emissions inventory due to closure or cancellation of three 
generating stations (Mohave, White Pine, and Toquop).
    Response 28-31: Section 169A of the Clean Air Act requires BART 
determinations on BART-eligible EGUs regardless of trends or ambient 
visibility conditions. Application of BART is one means by which we can 
ensure that downward emission and visibility impairment trends 
continue. EPA modeling of NOX from RGGS showed visibility 
impacts of up to 0.6 deciviews. This is not a negligible contribution 
to visibility impairment. EPA concluded in this case only that the 
incremental cost of SCR was not justified in relation to the visibility 
impact, not that the visibility impact was deminimis. Even if an 
individual pollutant or source category appears small to some 
commenters, the many segments of the emissions inventory together do 
cause visibility impairment, and each must be addressed in order to 
make progress towards the national goal of remedying visibility 
impairment from manmade pollution. EPA identifies stationary sources as 
an important category to evaluate in any BART analysis. In this case 
EPA approved the state's conclusion that SNCR was the appropriate BART 
control.

J. Emissions Limits

    Comment 32: The proposed BART NOX emissions limit (0.20 
lb/MMBtu) appears to result in a very small reduction in actual 
emissions when compared to the performance of the three units over the 
past two years.
    Response 32: EPA evaluated the potential NOX emissions 
reduction based on RGGS's permitted emission limits. Actual emissions 
in tons per year can vary substantially for external reasons such as a 
downturn in economic conditions generally or unusual weather 
conditions. Until the permitted emissions limits for RGGS are lowered, 
RGGS may emit pollutants in those amounts at any time. Therefore, for 
RGGS the permitted emissions limit is the only enforceable and certain 
amount to use in calculating potential emission reductions. RGGS is no 
longer subject to a long-term coal contract and may purchase coal on 
the spot market. Different coals may also lead to a change in 
NOX emissions. RGGS historically burned a very high BTU Utah 
bituminous coal that when combusted is expected to result in 
substantially higher NOX emissions than sub-bituminous coals 
or lower BTU bituminous coals from Colorado. RGGS has recently added 
these two coals to the fuel mix at RGGS and the NOX levels 
have decreased. EPA determined that the BART emission limit should be 
achieved when burning any of these coals. Setting a more stringent 
limit for BART achievable with LNB with OFA and SNCR could prevent RGGS 
from using only their historical Utah bituminous coal.
    Comment 33: Given the sensitivity of boiler operation, size, and 
configuration, SNCR may not be able to achieve the prescribed level of 
performance (0.20 lb/MMBtu) on a consistent basis.
    Response 33: NDEP will revise the enforceable permit limits to 
incorporate the NOX BART emissions limit of 0.20 lb/MMBtu 
when SNCR is installed and operating at RGGS. EPA expects that Nevada 
Energy, as the operator of RGGS, will ensure the LNB with OFA and SNCR 
system is designed to achieve a lower emissions rate than 0.20 lb/MMBtu 
to insure the BART limit is achieved in practice. RGGS will also be 
required to continue to operate its continuous emissions monitoring

[[Page 50947]]

system for NOX and report any excess emissions. If RGGS 
exceeds its emissions limit for NOX, NDEP, EPA or a citizen 
may bring an enforcement action that can result in penalties and 
injunctive relief. EPA has determined based on the record provided by 
the state that NDEP should be able to consistently operate at an 
emissions limit below 0.20 lb/MMBtu and the comment does not provide a 
basis for us to revise the final SIP approval or FIP.

K. Compliance Period

    Comment 34: Allowing five years from promulgation to install SNCR 
is excessive since SNCR can be installed in less than one year.
    Response 34: We have reconsidered the compliance date in our 
proposal in response to this comment. The Nevada BART regulation 
requires that BART control measures at RGGS must be installed and 
operating ``[o]n or before January 1, 2015; or (2) [n]ot later than 5 
years after approval of Nevada's state implementation plan for regional 
haze by the United States Environmental Protection Agency Region 9, 
whichever occurs first.'' NAC 445B.22096(2)(a) (emphasis added). We 
approved this requirement into the SIP on March 26, 2012 (effective 
April 25, 2012). 77 FR 17340. Therefore, the SIP-approved BART 
implementation deadline at RGGS for all pollutants, including 
NOX, is January 1, 2015. Consistent with this requirement, 
we are revising the compliance date in our FIP to January 1, 2015.

 L. Compliance Method

    Comment 35: Commenters state that the proposed method of 
demonstrating compliance with the NOX emissions rate is more 
stringent than the rule requires; does not allow the facility to take 
credit for the times a unit is not in operation; does not provide a way 
for a unit that is out of compliance for a period of time to get back 
into compliance without a continued period of non-compliance; and is in 
contrast to the BART modeling protocol that directs the use of a pounds 
per hour limit as opposed to an emissions rate limit for all BART 
eligible units over a 24-hour basis. Commenters propose an alternate 
compliance demonstration methodology that consists of a unit-wide 30-
calendar day rolling cap (in total lbs of NOX). The cap is 
calculated based upon each unit operating continuously (24 hours/day 
for 30 days) at its permitted maximum hourly heat rate (MMBtu/hr), and 
at its BART NOX emission limit (0.20 lb/MMBtu, which was 
determined based upon the operation of an ammonia injection system in 
conjunction with LNB). Compliance would then be demonstrated by 
calculating the unit-wide NOX emission rate (in total lbs of 
NOX) for the current calendar day, and adding it to the 
previous 29 calendar days' unit-wide NOX emission rate (in 
total lbs of NOX), and comparing this 30-calendar day total 
to the value of the unit-wide 30-calendar day rolling cap.
    Response 35: We disagree with the commenters, and further do not 
consider the commenters' proposed compliance demonstration methodology 
to meet BART requirements. The Regional Haze Rule defines BART as ``the 
best system of continuous emission reduction for each pollutant'', and 
requires that ``each source subject to BART maintain the control 
equipment required by the subpart and establish procedures to ensure 
such equipment is properly operated [* * *].'' \22\ EPA's BART 
determinations for coal fired EGUs have set concentration limits, 
expressed as lb/MMBtu for the various visibility impairing pollutants 
averaged over a 30-day period. The proposed and finalized limit is more 
flexible than typical EPA BART determinations in that it allows the 3 
units subject to BART to be averaged together to determine compliance 
(as requested by NDEP). BART limits are designed to be met at all 
times, not to provide for a facility to easily come back into 
compliance from a violation. We disagree that the facility requires 
additional flexibility to come back into compliance following an 
exceedance event, and consider a 30-day rolling average to provide a 
sufficient length of time to allow a facility to address and correct 
for perturbations that are reasonably expected to occur over the course 
of normal operations, and that cause short-term extra emissions.
---------------------------------------------------------------------------

    \22\ 40 CFR 51.301 and 40 CFR 51.308(e)(1)(v).
---------------------------------------------------------------------------

    Allowing a facility to take credit for times it is not operating, 
or for when it is not operating at maximum capacity, would allow RGGS 
to operate without the BART-required SNCR. SNCR can be expected to 
remove approximately 30 percent of the potential NOX 
emissions. If the overall capacity (as evaluated against the maximum 
potential MW output) fell below 70 percent in any 30-day period, under 
the commenter's proposal RGGS would not have to operate the SNCR 
ammonia injection at all to meet its limit. Therefore, this would not 
meet the BART definition application of the best system of continuous 
emission reduction.
    EPA recognizes that there are differences between BART emission 
limits and the emissions modeled to determine visibility improvements. 
This is the result of the models requiring short-term emission 
projections and the need for BART limits to have practical averaging 
times. Short averaging periods such as 1-hour averages would better 
correlate to the modeled emissions, but EPA has determined that such a 
short averaging period is not practical for facilities subject to BART. 
EPA has, therefore, directed that averaging times should be no longer 
than 30-day rolling averages and should include all periods of startup, 
shutdown, and malfunction. As discussed above, an emission limit that 
allows a facility to take credit for non-operation could lead to 
substantially higher 24-hour emissions of visibility impairing 
pollutants because the facility could turn off its SNCR.
    Specifically, the proposed emission cap, in the form as described 
by the commenters, does not by itself ensure that the control equipment 
determined as BART is continuously operated. We acknowledge that the 
regional haze regulations provide flexibility in establishing 
requirements and procedures to ensure that control equipment is 
properly and continuously maintained, and that a mass emission cap 
could be an acceptable BART emission limitation. In its current form, 
however, the emission cap proposed by the commenters allows a potential 
scenario in which, for a given unit-wide 30-calendar day period, one 
unit could operate at a NOX emission level of 0.40 lb/MMBtu 
in exchange for non-operation of another unit (essentially, operating 
that unit at 0.00 lb/MMBtu). An emission level of 0.40 lb/MMBtu 
corresponds to operation of LNB only, and does not reflect the 
operation of SNCR.
    In order to allow for better management of the elevated levels of 
emissions associated with startup events, we have revised our proposed 
determination method to be based on a boiler operating day average, 
rather than on a calendar day average. If based on a calendar day 
basis, the unit-wide 30-day rolling average could include as little as 
one hour of operation if the units were all offline for an outage that 
lasted longer than thirty days, because the first hour of operation 
would be the only data recorded in the last thirty calendar days. If 
based on a boiler operating day basis, the startup emissions ``spike'' 
would be averaged with emission data from before outage, which would 
reflect nonzero emissions values, rather than with data from during the 
outage, which would reflect zero emissions.

[[Page 50948]]

M. Environmental Compliance at RGGS

    Comment 36: Environmental controls, monitoring and practices have 
improved over recent years at the plant, which meets or exceeds all 
emissions limits, has reduced emissions, and has some of the lowest 
emissions of any plant in the country.
    Response 36: EPA agrees in part with the comment. Nevada Energy has 
installed controls that substantially reduced the PM emissions from 
RGGS and installed ROFA on unit 4 to reduce NOX emissions. 
Since monitoring began under the Acid Rain rules, RGGS has been among 
the coal fired electric generating units that emits the least 
SO2. The same is not true for NOX emissions from 
units 1, 2, and 3. By finalizing this action, EPA will ensure that 
there are also significant reductions in NOX emissions from 
RGGS, as required by the Regional Haze rule and Section 169A of the 
CAA. Each of the 3 units at RGGS will reduce NOX emissions 
from 0.46 lb/MMBtu to 0.20 lb/MMBtu.

N. Health Effects

    Comment 37: Pollution from RGGS is causing a variety of health 
problems (e.g., allergies, respiratory illnesses, heart ailments, skin 
lesions, thyroid disorders, sinus infections) for the Moapa Band of 
Paiutes who reside directly adjacent to RGGS.
    Response 37: In addition to regional haze, EPA assesses air quality 
regularly under the CAA with respect to setting and ensuring that areas 
in the country attain the NAAQS. The NAAQS are the health based 
standards that are set by EPA for the entire country. RGGS is located 
in an area that is designated as attainment for most of the NAAQS.\23\ 
This means that the air quality in the area surrounding RGGS is meeting 
most of the national health-based standards set by EPA.
---------------------------------------------------------------------------

    \23\ Please see http://www.epa.gov/region09/air/maps/maps_top.html for EPA Region IX air quality designations.
---------------------------------------------------------------------------

    Breathing air containing ozone can reduce lung function and 
increase respiratory symptoms, thereby aggravating asthma or other 
respiratory conditions. The area surrounding RGGS was designated 
nonattainment for the 1997 8-hour ozone NAAQS. The Clark County APCD 
and NDEP together are responsible for adopting and implementing 
programs for both stationary and mobile sources to bring the area into 
attainment for the 8-hour ozone NAAQS. On March 29, 2011, EPA published 
a direct final rule determining that the Clark County nonattainment 
area has attained the 1997 8-hour ozone NAAQS (76 FR 17343). Although 
the area has not been redesignated to attainment, the Clark County area 
continues to meet the 1997 8-hour ozone NAAQS. On April 30, 2012, EPA 
issued final designations for the 2008 8-hour ozone NAAQS. Clark County 
was designated attainment for this more stringent ozone standard.\24\
---------------------------------------------------------------------------

    \24\ http://www.epa.gov/ozonedesignations/2008standards/final/region9f.htm.
---------------------------------------------------------------------------

    The Moapa Band of Paiutes resides on land adjacent to RGGS. The 
stacks at RGGS release the exhaust at a high elevation for the purpose 
of preventing excessive concentration of pollutants in the immediate 
vicinity of the plant.\25\ Because the area surrounding RGGS is meeting 
the health-based 1997 and 2008 ozone NAAQS, EPA expects that air 
quality in the area is protective of human health. Because today's 
actions require additional reductions in NOX emissions, air 
quality will continue to improve. However, regardless of the attainment 
status of the surrounding area, EPA has been and will remain involved 
in efforts to ensure that the operation of RGGS meets all environmental 
requirements. Consequently, EPA believes it has implemented the 
executive order with respect to the Moapa Tribe in these actions 
implementing BART at RGGS.
---------------------------------------------------------------------------

    \25\ EPA Good Engineering Practice (GEP) http://www.epa.gov/scram001/guidance/guide/gep.pdf.
---------------------------------------------------------------------------

O. Environmental Justice

    Comment 38: EPA should implement Executive Order 13175 since 
pollution from RGGS is having a substantial direct effect on the tribe.
    Response 38: Ground-level ozone has the ability to impact human 
health, and is a secondary pollutant formed from precursor gases, 
primarily volatile organic compounds (VOCs) and NOX. 
However, monitored ozone concentrations throughout Clark County, 
including monitors nearest RGGS, meet the 2008 ozone standard. EPA 
considers the air quality in the vicinity of the plant to be protective 
of public health. However, regardless of the attainment status of the 
surrounding area, EPA has been and will remain involved in efforts to 
ensure that the operation of RGGS meets all environmental requirements.

P. Economic Impacts

    Comment 39: The high cost of SCR could cause RGGS to close, which 
would harm the local economy through the loss of jobs, the loss of 
contracts, and the loss of customers for local businesses.
    Response 39: EPA has determined that it is cost effective for RGGS 
to install and operate SNCR at Units 1, 2 and 3. Because EPA is not 
disapproving NDEP's determination to require SNCR rather than SCR, EPA 
does not expect the facility to close and thus the comment does not 
require additional response.

III. Summary of EPA Actions

    EPA is approving in part and disapproving in part the remaining 
portion of the Nevada Regional Haze SIP that implements the Regional 
Haze Rule that requires states to prevent any future and remedy any 
existing man-made impairment of visibility in mandatory Class I areas. 
EPA is approving Nevada's selection of a NOX emissions limit 
of 0.20 lb/MMBtu as BART for Units 1 and 2 at RGGS. EPA is disapproving 
two provisions of Nevada's BART determination for NOX at 
RGGS: the emissions limit for Unit 3 and the compliance method for all 
three units. EPA is promulgating a FIP to replace the disapproved 
provisions by establishing a BART emissions limit for NOX of 
0.20 lb/MMBtu at Unit 3, and a 30-day averaging period for compliance 
based on a heat input-weighted basis across all three units.
    EPA estimates the total, facility-wide capital costs of complying 
with this final BART determination for NOX to be $26.5 
million, and total annual costs (annualized capital costs plus 
additional operating costs) to be $4.3 million per year. The FIP 
requirements on Unit 3, which will require that unit to operate at 0.20 
lb/MMBtu instead of 0.28 lb/MMBtu, will result in an additional 
operating cost of approximately $75,000 per year and will achieve a 
NOX reduction of 393 tons per year. This final BART 
determination is expected to reduce emissions of NOX by 58 
percent, from 6,980 tons per year to 2,968 tons per year, resulting in 
a facility-wide average cost-effectiveness of about $1,078 per ton of 
NOX removed. EPA anticipates that this investment will 
reduce visibility impairment caused by RGGS by an average of 48 percent 
at 5 Class I areas within 300 km of the facility. A detailed summary of 
the cost and visibility benefits were provided in the Technical Support 
Document for the proposed rulemaking.

IV. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action finalizes a SIP approval and a source-specific FIP for 
a single stationary source, the Reid Gardner

[[Page 50949]]

Generating Station in Nevada. This type of action is exempt from review 
under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993) and is 
therefore not subject to review under Executive Order 13563 (76 FR 
3821, January 21, 2011).

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
Under the Paperwork Reduction Act, a ``collection of information'' is 
defined as a requirement for ``answers to * * * identical reporting or 
recordkeeping requirements imposed on ten or more persons * * *.'' 44 
U.S.C. 3502(3)(A). Because the FIP portion of this rulemaking applies 
to a single facility, Reid Gardner Generating Station, the Paperwork 
Reduction Act does not apply. See 5 CFR 1320(c).
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business as defined 
by the Small Business Administration's (SBA) regulations at 13 CFR 
121.201; (2) a small governmental jurisdiction that is a government of 
a city, county, town, school district or special district with a 
population of less than 50,000; and (3) a small organization that is 
any not-for-profit enterprise which is independently owned and operated 
and is not dominant in its field.
    After considering the economic impacts of this action on small 
entities, I certify that this final action will not have a significant 
economic impact on a substantial number of small entities. As the Reid 
Gardner Generating Station is not a small entity, the FIP for Reid 
Gardner Generating Station being finalized today does not impose any 
new requirements on small entities. See Mid-Tex Electric Cooperative, 
Inc. v. FERC, 773 F.2d 327 (D.C. Cir. 1985).

D. Unfunded Mandates Reform Act (UMRA)

    This rule will impose an enforceable duty on the private sector 
owners of Reid Gardner Generating Station. However, this rule does not 
contain a Federal mandate that may result in expenditures of $100 
million (in 1996 dollars) or more for State, local, and tribal 
governments, in the aggregate, or the private sector in any one year. 
EPA's estimate for the total annual cost for Reid Gardner Generating 
Station to lower its NOX emissions limit at Unit 3 to 0.20 
lb/MMBtu and for Units 1-3 to meet that NOX emissions limit 
on a 30 successive boiler operating day rolling average does not exceed 
$100 million (in 1996 dollars) in any one year. Thus, this rule is not 
subject to the requirements of sections 202 or 205 of UMRA. This action 
is also not subject to the requirements of section 203 of UMRA because 
it contains no regulatory requirements that might significantly or 
uniquely affect small governments. This rule will not impose direct 
compliance costs on Nevada, and will not preempt Nevada law. This final 
action will reduce the emissions of one pollutant from a single source, 
Reid Gardner Generating Station.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the States, on the relationship between 
the national government and the States, or in the distribution of power 
and responsibilities among the various levels of government, as 
specified in Executive Order 13132. This final action requires emission 
reductions of NOX at a specific private stationary source 
located in Nevada. Thus, Executive Order 13132 does not apply to this 
action.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Subject to the Executive Order 13175 (65 FR 67249, November 9, 
2000) EPA may not issue a regulation that has tribal implications, that 
imposes substantial direct compliance costs, and that is not required 
by statute, unless the Federal government provides the funds necessary 
to pay the direct compliance costs incurred by tribal governments, or 
EPA consults with tribal officials early in the process of developing 
the proposed regulation and develops a tribal summary impact statement.
    EPA has concluded that this action may have tribal implications 
because the Reid Gardner Generating Station is located adjacent to the 
Moapa Band of Paiutes reservation and the Tribe has expressed its 
concerns directly to EPA on several occasions. However, this final 
action will neither impose substantial direct compliance costs on 
tribal governments, nor preempt Tribal law. This final rule requires 
Reid Gardner Generating Station, a major stationary source located in 
Nevada, to reduce emissions of NOX under the BART 
requirement of the Regional Haze Rule. This will benefit air quality 
and the Moapa Band of Paiutes.
    EPA consulted with tribal officials early in the process of 
developing this regulation to permit them to have meaningful and timely 
input into its development. EPA met with President Anderson on August 
11, 2011, and again on April 17, 2012, to hear the Tribe's concerns 
directly. In addition, EPA held one public hearing on the Moapa 
Reservation on May 3, 2011, to ensure that tribal members had the 
opportunity to provide oral testimony.
    The Moapa Band of Paiutes joined a consortium of environmental 
groups to submit comments on our proposed rule. The main concern 
expressed by the consortium was that EPA was not requiring Reid Gardner 
Generating Station to install and operate the top NOX 
control option, selective catalytic reduction, as BART. The comments 
also raised potential health impacts and environmental justice concerns 
relative to the Moapa Band of Paiutes from not requiring the most 
stringent NOX control option.
    EPA summarized and responded to comments from the environmental 
consortium and Moapa Band of Paiutes. Our responsibilities under the 
Executive Order must be exercised in the context of our role under the 
CAA, which is to

[[Page 50950]]

review NDEP's plan and determine if it meets the CAA requirements. We 
have done a thorough review and have determined that NDEP has adopted 
an emission limit that meets BART for RGGS. That emission limit can be 
met with SNCR instead of SCR, but RGGS will still have to install 
additional pollution control equipment that will reduce NOX 
emissions. These emission reductions will not only improve visibility 
but will provide additional health benefits for the Moapa Band of 
Paiutes and other residents of Clark County. EPA has been and will 
remain involved in efforts to ensure that the operation of RGGS meets 
all environmental requirements.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks (62 FR 19885, April 23, 1997), applies to 
any rule that: (1) Is determined to be economically significant as 
defined under Executive Order 12866, and (2) concerns an environmental 
health or safety risk that EPA has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, the Agency must evaluate the environmental health or 
safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    This rule is not subject to Executive Order 13045 because it 
requires emissions reductions of NOX from a single 
stationary source. Because this action only applies to a single source 
and is not a rule of general applicability, it is not economically 
significant as defined under Executive Order 12866, and the rule also 
does not have a disproportionate effect on children. However, to the 
extent that the rule will reduce emissions of NOX, which 
contributes to ozone formation, the rule will have a beneficial effect 
on children's health by reducing air pollution that causes or 
exacerbates childhood asthma and other respiratory issues.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 (66 FR 28355 
(May 22, 2001)), because it is not a significant regulatory action 
under Executive Order 12866.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, 12 (10) (15 U.S.C. 272 note) 
directs EPA to use voluntary consensus standards (VCS) in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. VCS are technical standards 
(e.g., materials specifications, test methods, sampling procedures and 
business practices) that are developed or adopted by the VCS bodies. 
The NTTAA directs EPA to provide Congress, through annual reports to 
OMB, with explanations when the Agency decides not to use available and 
applicable VCS.
    Consistent with the NTTAA, the Agency conducted a search to 
identify potentially applicable VCS. For the measurements listed below, 
there are a number of VCS that appear to have possible use in lieu of 
the EPA test methods and performance specifications (40 CFR part 60, 
Appendices A and B) noted next to the measurement requirements. It 
would not be practical to specify these standards in the current 
rulemaking due to a lack of sufficient data on equivalency and 
validation and because some are still under development. However, EPA's 
Office of Air Quality Planning and Standards is in the process of 
reviewing all available VCS for incorporation by reference into the 
test methods and performance specifications of 40 CFR Part 60, 
Appendices A and B. Any VCS so incorporated in a specified test method 
or performance specification would then be available for use in 
determining the emissions from this facility. This will be an ongoing 
process designed to incorporate suitable VCS as they become available.

Particulate Matter Emissions--EPA Methods 1 through 5
Opacity--EPA Method 9 and Performance Specification Test 1 for Opacity 
Monitoring
NOX Emissions--Continuous Emissions Monitors

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994), establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this final rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations because it increases the 
level of environmental protection 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. This rule requires emissions reductions of one 
pollutant from a single stationary source, Reid Gardner Generating 
Station.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. Section 804 exempts from section 801 the following types 
of rules (1) rules of particular applicability; (2) rules relating to 
agency management or personnel; and (3) rules of agency organization, 
procedure, or practice that do not substantially affect the rights or 
obligations of non-agency parties. 5 U.S.C. 804(3). EPA is not required 
to submit a rule report regarding today's action under section 801 
because this is a rule of particular applicability and only applies to 
one facility, the Reid Gardner Generating Station.

L. Petitions for Judicial Review

    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by October 22, 2012. Filing a 
petition for reconsideration by the administrator of this final rule 
does not affect the finality of this rule for the purposes of judicial 
review nor does it extend the time within which a petition for judicial 
review may be filed, and shall not postpone the effectiveness of such 
rule or action. This action may not be challenged later in proceedings 
to enforce its requirements. (See CAA section 307(b)(2)).

[[Page 50951]]

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Nitrogen oxides, Particulate 
matter, Reporting and recordkeeping requirements, Sulfur dioxide, 
Visibility, Volatile organic compounds.

    Dated: August 13, 2012.
Lisa P. Jackson,
Administrator.
    Part 52, chapter I, title 40 of the Code of Federal Regulations is 
amended as follows:

PART 52--[AMENDED]

0
1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart DD--Nevada

0
2. Section 52.1470 is amended by:
0
a. In paragraph (c), Table 1 revising the entry for ``445B.22096.''
0
b. In the table in paragraph (e), revising the entry for ``Nevada 
Regional Haze State Implementation Plan (October 2009)''.
    The revised text reads as follows:

Sec.  52.1470  Identification of plan.

* * * * *
    (c) * * *

                              Table 1--EPA-Approved Nevada Regulations and Statutes
----------------------------------------------------------------------------------------------------------------
                                                     State  effective
         State citation             Title/subject          date        EPA approval date  Additional explanation
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
445B.22096, excluding the NOX    Control measures    1/28/10.........  [Insert page       Included in
 averaging time and control       constituting                          number where the   supplemental SIP
 type for units 1, 2 and 3 and    BART; limitations                     document begins    revision submitted on
 the NOX emission limit for       on emissions.                         8/23/12].          September 20, 2011,
 unit 3 in sub-paragraph                                                                   and approved as part
 (1)(c), all of which EPA has                                                              of approval of Nevada
 disapproved.                                                                              Regional Haze SIP.
                                                                                           Excluding the NOX
                                                                                           averaging time and
                                                                                           control type for
                                                                                           units 1, 2 and 3 and
                                                                                           the NOX emission
                                                                                           limit for unit 3 of
                                                                                           NV Energy's Reid
                                                                                           Gardner Generating
                                                                                           Station, all of which
                                                                                           EPA has disapproved.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *
    (e) * * *

 
----------------------------------------------------------------------------------------------------------------
                                     Applicable
     Name of SIP provision          geographic or    State  submittal  EPA approval date        Explanation
                                 nonattainment area        date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Nevada Regional Haze State       State-wide........  11/18/09........  [Insert page       Excluding Appendix A
 Implementation Plan (October                                           number where the   (``Nevada BART
 2009), excluding the BART                                              document begins    Regulation''). The
 determination for NOX at Reid                                          8/23/12].          Nevada BART
 Gardner Generating Station in                                                             regulation, including
 sections 5.5.3, 5.6.3 and 7.2,                                                            NAC 445B.029,
 which EPA has disapproved.                                                                445B.22095, and
                                                                                           445B.22096, is listed
                                                                                           above in 40 CFR
                                                                                           52.1470(c).
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

0
3. Section 52.1488 is amended by:
0
a. Revising paragraph (e).
0
b. Adding paragraph (f).
    The revision and addition read as follows:

Sec.  52.1488  Visibility protection.

* * * * *
    (e) Approval. On November 18, 2009, the Nevada Division of 
Environmental Protection submitted the ``Nevada Regional Haze State 
Implementation Plan.'' With the exception of the BART determination for 
NOX at Reid Gardner Generating Station in sections 5.5.3, 
5.6.3 and 7.2; the NOX averaging time and control type for 
units 1, 2 and 3 in sub-paragraph (1)(c) of Nevada Administrative Code 
section 445B.22096; and the NOX emission limit for unit 3 in 
sub-paragraph (1)(c) of Nevada Administrative Code section 445B.22096; 
the Nevada Regional Haze State Implementation Plan, as supplemented and 
amended on February 18, 2010 and September 20, 2011, meets the 
applicable requirements of Clean Air Act sections 169A and 169B and the 
Regional Haze Rule in 40 CFR 51.308.
    (f) Source-specific federal implementation plan for regional haze 
at Reid Gardner Generating Station Units 1, 2 and 3. This paragraph (f) 
applies to each owner and operator of the coal-fired electricity 
generating units (EGUs) designated as Units 1, 2, and 3 at the Reid 
Gardner Generating Station in Clark County, Nevada.
    (1) Definitions. Terms not defined below shall have the meaning 
given to them in the Clean Air Act or EPA's regulations implementing 
the Clean Air Act. For purposes of this paragraph (f):
    Ammonia injection shall include any of the following: anhydrous 
ammonia, aqueous ammonia or urea injection.

[[Page 50952]]

    Boiler operating day means any 24-hour period between 12:00 
midnight and the following midnight during which any fuel is combusted 
at any of the units identified in paragraph (f) of this section.
    Combustion controls shall mean new low NOX burners, new 
overfire air, and/or rotating overfire air.
    Continuous emission monitoring system or CEMS means the equipment 
required by 40 CFR Part 75 to determine compliance with this paragraph 
(f).
    NOX means nitrogen oxides expressed as nitrogen dioxide 
(NO2).
    Owner/operator means any person who owns or who operates, controls, 
or supervises an EGU identified in paragraph (f) of this section.
    Unit means any of the EGUs identified in paragraph (f) of this 
section.
    Unit-wide means all of the EGUs identified in paragraph (f) of this 
section.
    Valid data means data recorded when the CEMS is not out-of-control 
as defined by part 75 and which meets the relative accuracy 
requirements of this paragraph.
    (2) Emission limitations--the total discharge of NOx from Units 1, 
2, and 3, expressed as NO2, shall not exceed 0.20 lb/MMBtu 
determined over a 30 successive boiler operating day period. For each 
boiler operating day, hourly emissions of NO2, in pounds of 
NO2, for units 1, 2 and 3 for that day shall be summed 
together. For each boiler operating day, heat input, in millions of 
BTU, for units 1, 2 and 3 for that day shall be summed together. Each 
day the 30 successive boiler operating day NO2 emission 
rate, in lb/MMBtu, shall be determined by adding together that day and 
the preceding 29 boiler operating days' pounds of NO2 and 
dividing that total pounds of NO2 by the sum of the heat 
input during the same 30-day period.
    (3) Compliance date. The owners and operators subject to this 
section shall comply with the emissions limitations and other 
requirements of this section by January 1, 2015 and thereafter.
    (4) Testing and monitoring. (i) At all times after the compliance 
date specified in paragraph (f)(3) of this section, the owner/operator 
of each unit shall maintain, calibrate, and operate a CEMS, in full 
compliance with the requirements found at 40 CFR part 75, to accurately 
measure NOX, diluent, and stack gas volumetric flow rate 
from each unit. In addition to these requirements, relative accuracy 
test audits shall be performed for both the NO2 pounds per 
hour measurement and the hourly heat input measurement. Each such 
relative accuracy test audit shall have a relative accuracy, as defined 
in 40 CFR part 60, appendix F, section 2.6, of less than 20 percent. 
This testing shall be evaluated each time the 40 CFR part 75 monitors 
undergo relative accuracy testing. Compliance with the emission limit 
for NO2 shall be determined by using valid data that is 
quality assured in accordance with the requirements of this paragraph. 
(ii) If a valid NOX pounds per hour or heat input is not 
available for any hour for a unit, that heat input and NOX 
pounds per hour shall not be used in the calculation of the unit-wide 
rolling 30 successive boiler operating day average. Each unit shall 
obtain at least 90 percent hours of data over each calendar quarter. 40 
CFR part 60 Appendix A Reference Methods may be used to supplement the 
part 75 monitoring.
    (iii) Upon the effective date of the unit-wide NOX 
limit, the owner or operator shall have installed CEMS software that 
meets with the requirements of this section for measuring 
NO2 pounds per hour and calculating the unit-wide 30 
successive boiler operating day average as required in paragraph (f)(2) 
of this section.
    (iv) Upon the completion of installation of ammonia injection on 
any of the three units, the owner or operator shall install, and 
thereafter maintain and operate, instrumentation to continuously 
monitor and record levels of ammonia consumption for that unit.
    (5) Notifications. (i) The owner or operator shall notify EPA 
within two weeks after completion of installation of combustion 
controls or ammonia injection on any of the units subject to this 
section.
    (ii) The owner or operator shall also notify EPA of initial start-
up of any equipment for which notification was given in paragraph 
(f)(5)(i) of this section.
    (6) Equipment Operations. After completion of installation of 
ammonia injection on any of the three units, the owner or operator 
shall inject sufficient ammonia to minimize the NOX 
emissions from that unit while preventing excessive ammonia emissions.
    (7) Recordkeeping. The owner or operator shall maintain the 
following records for at least five years: (i) For each unit, CEMS data 
measuring NOX in lb/hr, heat input rate per hour, the daily 
calculation of the unit-wide 30 successive boiler operating day rolling 
lb NO2/MMbtu emission rate as required in paragraph (f)(2) 
of this section. (ii) Records of the relative accuracy test for 
NOX lb/hr measurement and hourly heat input
    (iii) Records of ammonia consumption for each unit, as recorded by 
the instrumentation required in paragraph (f)(4)(iv) of this section.
    (8) Reporting. Reports and notifications shall be submitted to the 
Director of Enforcement Division, U.S. EPA Region IX, at 75 Hawthorne 
Street, San Francisco, CA 94105. Within 30 days of the end of each 
calendar quarter after the effective date of this section, the owner or 
operator shall submit a report that lists the unit-wide 30 successive 
boiler operating day rolling lb NO2/MMBtu emission rate for 
each day. Included in this report shall be the results of any relative 
accuracy test audit performed during the calendar quarter.
    (9) Enforcement. Notwithstanding any other provision in this 
implementation plan, any credible evidence or information relevant as 
to whether the unit would have been in compliance with applicable 
requirements if the appropriate performance or compliance test had been 
performed, can be used to establish whether or not the owner or 
operator has violated or is in violation of any standard or applicable 
emission limit in the plan.

[FR Doc. 2012-20503 Filed 8-22-12; 8:45 am]
BILLING CODE 6560-50-P