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SECTION D.2.2.3.2 

NEVADA’S RESPONSE 

(to U.S. Department of Interior, National Park Service Comment Letter) 

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2.2.3.2 Nevada’s Response 

Introduction

The focus of the NPS follow-up comments is the Reid Gardner Generating Station, particularly 

as related to the BART emission limit for SO2 and the determination of the BART control 

technology for NOx. NDEP notes that the NPS concurs with the BART technology NDEP has 

identified for the three units at the Tracy Generating Station and the two units at the Fort 

Churchill Generating Station as expressed in their follow-up comment to Comment 7 (see 

Appendix C). 

 

USEPA’s BART guidance states: 

“The visibility regulations define BART as follows: 

Best Available Retrofit Technology (BART) means an emission limitation based on the degree of 

reduction achievable through the application of the best system of continuous emission reduction for 

each pollutant which is emitted by . . . [a BART-eligible source]. The emission limitation must be 

established, on a case-by-case basis, taking into consideration the technology available, the costs of 

compliance, the energy and non-air quality environmental impact of compliance, any pollution 

control equipment in use or in existence at the source, the remaining useful life of the source, and the 

degree of improvement in visibility which may reasonably be anticipated to result from the use of 

such technology.”2

 

The preamble to the BART guidance indicates that states are free to determine the weight and 

significance to be assigned to each statutory factor

3

 and also suggests the BART determination 

process allows states to identify a technology which does not pose unacceptable costs of 

compliance, energy and/or nonair quality environmental impacts4

. In addition, the guidance 

provides that the states use average and incremental costs to determine the reasonableness of

compliance costs5

. 

NDEP identified the BART technologies and emissions limits on a case-by-case basis through an 

analysis of the five statutory factors consistent with EPA guidance. NDEP evaluated the costs of

compliance based on the average cost, incremental cost and capital cost. We evaluated the 

degree of visibility improvement using NV Energy’s modeling data, which we supplemented 

with the expected emissions reductions since modeled visibility impacts are proportional to 

emission rates. NDEP consistently evaluated the cost and visibility data by looking at clear 

breaks in the cost effectiveness of the BART controls and resulting visibility improvement or 

emissions reductions. Examination of Table 1, Appendix C, of this SIP reveals these breaks in 

cost benefit, as do the least cost envelopes presented as Figure 1 in each of the NDEP BART 

determination review reports in Appendix B. 

 

2 40 CFR Part 51 Appendix Y (IV) (A) 3

 70 FR page 39130 4

 70 FR page 39130 5 40 CFR Part 51 Appendix Y (IV) (D) (4 ) (b)

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BART is only one of the tools available for states to utilize in a long-term strategy to meet their 

2018 reasonable progress goal. Nevada’s 2018 reasonable progress goal is better than the 

uniform rate of progress when evaluated with NDEP’s proposed BART emission limits. NDEP 

deems our determination of BART control technologies and emission limits as consistent with 

USEPA guidance and the RHR. 

NPS Follow-Up Comments

The NPS follow-up comments are reproduced below in italics with NDEP’s follow-up response 

in plain text. Comment numbers refer to the original FLM comments received during the FLM 

review with the commenter and page number enclosed in parenthesis. Only FLM comments 

with NPS follow-up comments are listed below. See Appendix C for the complete set of FLM 

comments on the FLM consultation draft of the SIP. 

COMMENT 6 (FS) NPS follow-up:

The BART program is designed to set emission limits to protect and improve visibility, which is a 

transitory, short-term attribute. NDEP should facilitate the goals of the BART program by 

regulating short-term emissions of NOx, a pollutant that significantly impairs visibility in the 

area. 

NDEP follow-up response: 

Nevada has identified NOx emission limits based on 12-month rolling averages. We have chosen 

this time period based on our industry’s operational experience with retrofits. NV Energy has 

installed rotating opposed fire air on one of its units at Reid-Gardner (unit 4) and confronted 

serious operational problems, creating a high degree of variability in the operational 

characteristics of the unit. In order to ensure that industry is not out of compliance because of 

such issues, Nevada has chosen the 12-month rolling average. It should be noted that because it 

is a rolling average, the average is calculated each month and not simply at the end of a full 

calendar year. 

NDEP deems our BART emission limits do facilitate the goals of the BART program. 

Examination of IMPROVE monitor data representing Class I areas in the states adjacent to 

Nevada reveals that NOx contributes to visibility impairment, but at levels considerably less than 

other pollutants (see NDEP’s response to NGO Comment 4 in section 2.2.4 below). Those Class 

I areas where NOx significantly impairs visibility are clearly influenced by mobile sources (i.e., 

Zion and Craters of the Moon). 

No changes were made to Nevada’s draft RH SIP as a result of this comment. 

COMMENT 7 (NPS-FWS p.5) NPS follow-up:

It appears that NDEP has based its BART determinations upon three factors, capital cost, cost 

per ton, and incremental cost per ton. NDEP cites the $8 million capital cost of ROFA+Rotamix 

at Reid Gardner Generating Station (RGGS) as one example of a parameter it considered. This 

is the highest capital cost of any NOx control strategy accepted by NDEP. Use of this cap on 

capital cost improperly excludes controls that may be more effective on other bases (e.g., $/ton, 

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