SALT RIVER PROJECT 

P.O. Box 5 2025 

Phoenix, AZ 8507 2-2025 

(602) 236-5262 

Fax (602) 236-6690 

Kelly Barr@srpnet. com 

July 20, 2012 

Ms. Deborah Jordan 

Director, Air Division, Region 9 

United States Environmental Protection Agency 

75 Hawthorne Street 

San Francisco, CA, 94105 

Re: SNCR Demonstration Test 

Navajo Generating Station 

Dear Ms. Jordan: 

KELLY J. BARR, ESQ. 

Senior Director 

Environmental Management, 

Policy and Compliance 

As you are aware, Salt River Project Agricultural Improvement and Power District (SRP) recently 

completed a Demonstration Test for Selective Non-Catalytic Reduction (SNCR) at Navajo 

Generating Station (NGS). The test was conducted to provide supplemental information t o the 

updated Best Available Retrofit Technology (BART) analysis that was submitted to the U.S. 

Environmental Protection Agency (EPA) in January 2012. The purpose of this letter is to 

summarize the results of the Demonstration Test and to provide a recommendation regarding a 

potential permit limit that would be achievable at NGS using this technology. 

The Demonstration Test was conducted on Unit 3 at NGS during a three-week period in May 

2012. It is important to note that a minor overhaul that had just been completed on this unit 

included maintenance activities on the Low-NOx Burners. Between overhauls, emissions 

reduction performance will degrade due to normal equipment wear-and-tear. Th is trend has 

been consistently observed with the Low-NOx Burners at NGS. Therefore, the results obta ined 

in the Demonstration Test most likely represent the best possible performance that SNCR could 

achieve at NGS. 

The test demonstrated that the addition of SNCR consistently reduced baseline nitrogen oxide 

{NOx) emission by approximately 20% without any noticeable impact on plant operations. The 

test was conducted using varying amounts of urea reagent. Table 1 contains the test results 

that are most relevant to establishing a NOx permit limit for SNCR at NGS. 
Ms. Deborah Jordan 

July 20, 2012 

Page Two 

Table 1. Summary of SNCR Demonstration Test Results for Unit 3 

Parameter Test Condition #1 Test Condition #2 

Unit Load- Net (MW) 750 750 

Baseline NOx (lb/MMBtu) 0.22 0.21 

Controlled NOx (lb/MMBtu) 0.16 0.17 

Ammonia Slip (ppm) 3.1 0.4 

Although actual stack emissions generally fell within the range represented in the January 2012 

BART report (0.15-0.18 lb/MMBtu), values measured at the lower end of the range resulted in 

higher than expected ammonia slip. Considering the tradeoff between NOx reduction and 

ammonia slip, and that a sufficient operating margin is necessary for compliance, SRP believes 

that a NOx permit limit of 0.20 lb/MMBtu would be achievable using SNCR at NGS. 

SRP continues to strongly believe that Low-NOx Burners and Sepa rated Overfire Air is the most 

cost-effective control option for NGS, and a BART proposal that is based on this technology 

would not introduce the risk of broader adverse economic consequences. 

We appreciate EPA's review and consideration of this information. If you have any questions 

regarding the content of this letter, please feel free to contact me at 602-236-5262. 

Sincerely, 

Kelly J. Barr