### May **10, 2013** 

**Gregory Nudd**  

## Tilcson **Electric Power**  **CDmpang 88**  **East Broaqway**  **Blvd (85701)**  **Mail Stop**  **HQW602, Post**  **Office Box**  **711 Tucson,**  **Arizona 85702** 

**Submitted via**  **email**



### United **States Environmental**  **Protection Agency**  **Region 9,**  **Air Division (AIR-2)**  **75 Hawthorne Street**  **San Francisco,**  **CA 94105**  **Telephone (520)**  **918-8351 Email:**  **EBakken@tep.com**

**RE:** 

### Visibility **Modeling and**  **Control Cost**  **Information Relating**  **to H**  

### Wilson **Sundt Generating**  **Station, Tucson,**  **Arizona To**  **Mr. Nudd:**  **Tucson Electric**  **Power Company**  **(TEP), a**  **wholly-owned subsidiary**  **of UniSource**  **Energy Corporation**  **(NYSE: UNS),**  **owns and**  **operates the**  **H. Wilson**  **Sundt Generating**  **Station (Sundt)**  **in Tucson,**  **Arizona. The**  **Sundt station**  **consists of**  **four electricity**  **generating units,**  **three of**  **which are**  **fired by**  **natural gas**  **and one**  **(Unit 4),**  **which is**  **predominantly coal-fired,**  **but is**  **also capable**  **of firing**  **natural gas.**  **On December**  **22, 2012,**  **EPA issued**  **a proposed**  **rule disapproving**  **certain aspects**  **of Arizona's**  **State Implementation**  **Plan (SIP)**  **for Regional**  **Haze. One**  **of the**  **provisions that**  **EPA proposes**  **to disapprove**  **is the**  **Arizona Department**  **of Environmental Quality's**  **(ADEQ) conclusion**  **that Sundt**  **Unit 4**  **is not**  **"BART-eligible" because**  **the unit**  **was "reconstructed"**  **after August**  **7, 1 9** **77, and**  **was therefore,**  **not "in**  **existence" as**  **of that**  **date, which**  **is one**  **the requirements**  **for BART**  **eligibility. TEP**  **submitted comments**  **dated March**  **6, 2013,**  **regarding EPA's**  **proposal, in**  **which we**  **provided a**  **detailed analysis**  **supporting ADEQ's**  **conclusion that**  **Sundt Unit**  **4 is**  **not BART-eligible.**  **Those comments**  **are attached**  **(Attachment A).**  **On March**  **29, 2013,**  **ADEQ proposed**  **revisions to**  **its Regional**  **Haze SIP,**  **reaffirming its**  **conclusion that**  **Sundt Unit**  **4 is**  **not BART-eligible.**  **TEP strongly supports ADEQ's position**  **both on**  **technical grounds,**  **as well**  **as Arizona's**  **legal argument**  **that its**  **actions relating**  **to the**  **Arizona SIP**  **are within**  **the authority**  **granted under**  **the Clean**  **Air Act**  **and are**  **in compliance**  **with the**  **Act's provisions.**  **That said,**  **TEP was**  **notified via**  **email on**  **February 27,**  **2013, that**  **EPA was**  **proceeding with**  **a BART**  **determination for**  **Sundt Unit**  **4, and**  **that EPA**  **welcomed any**  **information TEP**  **could provide**  **relevant to**  **such an**  **analysis. Separately,**  **EPA provided**  **a draft**  **report Mr.**  **Gregory Nudd**  **May 10,**  **2013 Page**  **2** 

### and **supporting documents**  **prepared on**  **behalf of**  **EPA documenting**  **a Five-Factor**  **Best Available Retrofit Technology**  **(BART) analysis**  **1 on**  **Sundt Unit**  **4 ("draft**  **BART report").**  **Notwithstanding TEP's**  **position that**  **Sundt Unit**  **4 is**  **not BART**  **eligible, TEP**  **provides the**  **following comments**  **on the**  

### draft **BAR T**  **report, and**  **additional information**  **to assist**  **EPA in**  **developing a**  **thorough and**  **accurate analysis,**  **should they**  **elect to**  **propose and**  **ultimately finalize**  **a BART**  **determination for**  **Sundt Unit**  **4. TEP**  **will continue**  **to evaluate**  **the data**  **and analysis**  **that EPA**  **has provided**  **and will**  **respond with**  **any new**  **information as**  **available. Similarly,**  **TEP would welcome**  **any new**  **or updated**  **analysis that**  **EPA may**  **develop. Sundt**  **Unit 4**  **Design and**  **Operational Information**  

### Sundt **Unit 4,**  **completed in**  **1967, was**  **the final**  **of four**  **steam electric generating**  **units constructed**  **as part**  **of the Irvington Generating Station.**  **The Irvington Generating**  **Station was**  **subsequently renamed**  **the H.**  **Wilson Sundt**  **Generating Station,**  **and is**  **referred to**  **as "Sundt". Sundt**  **Unit 4**  **was originally**  **constructed to**  **fire oil**  **or natural**  **gas. In**  **the 1980s,**  **Sundt Unit**  **4 was**  **converted to**  **bum coal**  **in response**  **to a**  **prohibition order issued**  **under Section**  **301 (c)**  **of the**  **Power Plant**  **and Industrial**  **Fuel Act**  **of 1978.**  **As part**  **of the**  **coal conversion,**  **the unit**  **was equipped**  **with a**  **fabric filter**  **for particulate**  **control. In**  **1999, the**  **unit was**  **upgraded with**  **low-NOx burners**  **and overfire**  **air, designed**  **to meet**  **Phase II**  **Acid Rain requirements.**  **The coal**  **conversion did**  **not affect**  **the unit's**  **ability to**  **bum natural**  **gas, however,**  **the generating capacity**  **of the**  **unit while**  **firing coal**  **was reduced**  **compared to**  **its capacity**  **on natural**  **gas. That**  **is primarily**  **due to**  **fact that**  **the amount**  **of coal**  **that can**  **be introduced**  **to the**  **boiler is**  **limited by**  **the size**  **of the**  **boiler. Excess**  **coal injection**  **causes the**  **flame to**  **impinge on**  **the back**  **wall of**  **the boiler**  **which damages**  **the boiler**  **tubes. TEP**  **reports the**  **capacity of**  **Unit 4**  **to the**  **Energy Information**  **Association (EIA)**  **as 173**  **MW as**  **that is**  **the nameplate capacity**  **of the**  **unit while**  **firing natural**  **gas. However,**  **the maximum**  **gross capacity**  **that the**  **unit could**  **operate at,**  **for a**  **sustained period**  **of time,**  **while burning**  **coal is**  **approximately 130**  **MW. This maximum**  **capacity on**  **coal is**  **evident on**  **the chart**  **in Attachment**  **B, which**  **shows the**  **actual gross**  **load of**  **Sundt Unit**  **4 for**  **all of**  **calendar year**  **201 1,**  **a year**  **during which**  **the unit was**  **predominantly coal-fired.**  **While Sundt**  **Unit 4**  **is capable**  **of firing**  **natural gas,**  **it has**  **operated predominantly**  **as a**  **coal-fired unit**  **since the**  **coal conversion.**  **However, recently**  **Unit 4**  **has been**  **operating on**  **natural gas**  **for extended periods**  **of time**  **due to**  **historically low**  **natural gas**  **prices. In**  **fact, Sundt**  **Unit 4**  **operated in**  **natural gas-fired mode**  **for significant**  **portions of**  **2009, 2010,**  **and 2012.**  **Again, in**  **201 1,**  **Unit 4**  **primarily burned**  **coal. The**  

### draft **BART report**  **prepared for**  **EPA used**  **a mix**  **of operating**  **and emissions**  **data from**  **2008 through**  **2011. TEP**  **believes that**  **EPA's analysis**  **should be**  **based on**  **operating and**  **emissions data**  **for 2011,**  **as that**  **is the**  **most current**  **year that**  **the unit**  **operated 1**  **UNC I**  **ICF- Technical**  **Analysis of**  **Arizona and**  **Hawaii Regional**  **Haze FIPs:**  **Task 7:**  **Five-Factor BART Analysis**  **for TEP**  **Sundt (Irvington),**  **delivered October 9,**  **2012 Mr.**  **Gregory Nudd**  **May 10,2013**  **Page 3**  

### primarily **on coal**  **and its**  **operation during**  **that year**  **is the**  **most representative**  **for BART**  **analysis purposes.**  **The table**  **below presents**  **the appropriate**  **data for**  **use in**  **a BART**  **analysis on**  **Sundt Unit**  **4.**

**Generation 555,491**  **MWh Gross**  **Ca p**  **acit y**  **130 MW**  **Ca p**  **aci ty**  **Factor 49%**  **Average S02**  **Emission Rate**  **0.729 lbs/MMBtu**  **Average NOx**  **Emission Rate**  **0.445 lbs/MMBtu**  **Cost Estimates**  **for Control**  **of 802**  **and NOx**  

### TEP **reviewed the**  

### draft **BAR T**  **report, including**  **the accompanying**  **spreadsheets detailing**  **the cost**  **estimates for**  **the control options evaluated**  **as potential**  **BART. Based**  **on TEP's**  **review and**  **our understanding**  **of Sundt**  **Unit 4,**  **it did**  **not appear**  **that the**  **cost estimates**  **considered site**  **specific factors**  **that could**  **play a**  **significant role**  **in the**  **total cost**  **of retrofitting Sundt**  **Unit 4**  **with air**  **pollution controls.**  **Therefore, TEP**  **hired Burns**  **and McDonnell**  **(BMcD) to**  **review the**  

### draft **BAR T**  **report and**  **to prepare**  **comparative cost**  **estimates for**  **the control**  **options under**  **consideration. BMcD**  **is a**  **world leader**  **in air**  **pollution control**  **projects and**  **has provided**  **engineering design**  **and construction**  **management on**  **hundreds of**  **air pollution**  **control projects**  **over the**  **past 40**  **years. In**  **addition, BMcD**  **has been**  **providing engineering**  **services to**  **TEP at**  **Sundt for**  **several years,**  **and as**  **a result**  **they are**  **very familiar**  **with the**  **design and**  **operation of**  **that facility.**  **BMcD's cost**  **estimates were,**  **for each**  **control option,**  **greater than**  **the cost**  **estimates prepared**  **by EPA's**  **contractor (see**  **Attachment C).**  **Three of**  **the five**  **three technologies**  **evaluated significantly**  **exceeded the**  **EPA's screening**  **cost effectiveness**  **threshold of**  **$ 5,000/ton**  **(see Table**  **1, Attachment**  **C). Selective**  **Catalytic Reduction**  **(SCR) Dry**  **Flue Gas**  **Desulphurization (DFGD)**  **Wet Flue**  **Gas Desulphurization**  **(DFGD) $** **7,874/ton $9,359** **/ ton**  **$ 8,229/ton**  **The differences**  **between the**  **estimates prepared**  **by BMcD**  **and those**  **in the**  

### draft **BART report**  **are detailed**  **in the BMcD**  **report. In**  **general terms,**  **the reasons**  **that the estimates**  **in the**  

### draft **BAR T**  **report are**  **lower than**  **those prepared**  **by BMcD can be**  **grouped as**  **follows:**

**•** 

### Failure **to take**  **into account**  **site-specific features**  **of Sundt**  **Unit 4**  **such as:** 

**o** 

### congestion **in the**  **areas where**  **new equipment**  **would be**  **installed or**  **tied-in due**  **to the**  **presence of**  **boiler steel,**  **supporting structures,**  **coal handling**  **equipment and**  **the existing**  **baghouse, o**  

### the **horizontal duct**  **arrangement of**  **the existing**  **air preheater,**  **which would**  **require extensive**  **reconfiguring and/or**  **replacement of**  **the air**  **preheater for**  **installation of**  **SCR, Mr.**  **Gregory Nudd**  **May 10,2013**  **Page4**
**o** 

### the **presence of**  **the Sundt**  **Unit 3**  **cooling water**  **recirculation line**  **routed**

**adjacent to**  **Unit 4,**  **where new**  **equipment would**  **normally be**  **located, •**  

### Failure **to adjust**  **technology unit**  **costs to**  **account for**  **the fact**  **that Sundt**  **Unit 4**  **is relatively small and unit**  **costs increase**  **with decreasing facility size,**  **•** 

### Failure **to escalate**  **previously developed**  **cost estimate**  **figures to**  **the current**  **date, •**  

### Underestimation **of owners**  **costs and**  **costs associated**  **with engineering**  **and construction**  **management •**  

### Underestimation **of operation**  **and maintenance**  **costs for**  **complex systems.**  **The BART**  **Guidelines 2**  **provide for**  **incorporation of**  **site-specific factors,**  **or "elements** 
**...**

**that are**  **not addressed**  **by the**  **Cost Control**  **Manual", in**  **determining the**  **cost of**  **control for**  **BART. Some**  **of these**  **elements cannot**  **be identified**  **through literature**  **research, and**  **require knowledge**  **of, or**  **at a**  **minimum a**  **visit to**  **the site.**  **The most**  **significant site-specific**  **factors relevant to**  **determining BART**  **for Sundt**  **Unit 4**  **have been**  **identified by**  **BMcD, and**  **these factors**  **should be**  **incorporated into**  **any BART**  **determination for**  **that facility.**  **Visibility Modeling**  

### The 

### draft **BAR T**  **report includes**  **the results**  **of visibility**  **modeling for existing conditions**  **(i.e. Base**  **Case) and**  **11 control**  **retrofit scenarios.**  **TEP hired**  **AECOM to**  **(1) review**  **the results**  **of modeling**  **analysis included**  **in the**  

### draft **BART report,**  **(2) make**  **recommendations for**  **appropriate modifications**  **to the**  **modeling approach**  **used in**  **the** 

### draft **BAR T**  **report, and**  **(3) to**  **conduct visibility modeling**  **on select**  **control scenarios incorporating any**  **such modification**  **(see Attachment**  **D). Modeling**  **Appr oach**  **The modeling**  **approach used**  **by AECOM**  **was generally**  **in accordance**  **with that**  **used to**  **develop the**  

### draft **BART report,**  **with two**  **important modifications**  **described below.**  **While AECOM**  **conducted its**  **modeling using**  **CALPUFF version**  **5.8, they**  **point out**  **in their**  **report that**  **that version**  **of CALPUFF**  **suffers from**  **coding "bugs"**  **and uses**  **outdated chemistry**  **algorithms. In**  **fact, there**  **have been**  **several studies**  **conducted over**  **the last**  **few years**  **demonstrating that**  **the chemistry**  **and the**  **dispersion functions of**  **CALPUFF version**  **5.8 over-estimate**  **the visibility**  **impacts of**  **NOx emissions**  **in Class**  **I areas**  **and thus,**  **erroneously over-estimate**  **the visibility**  **improvements from**  **proposed BART**  **controls leading**  **to biased**  **cost benefit**  **( $** **/dv) values.**  **TEP believes**  **that EPA**  **should adopt**  **a newer**  **version of**  **CALPUFF (version 6.42)**  **as the**  **approved regulatory**  **version for**  **Regional Haze**  **modeling. AECOM**  **also identified**  **background amm** 

### onia **as an**  **area to**  **improve the**  **modeling approach.**  **Ammonia plays**  **an important**  **role in**  **the formation**  **of compounds,**  **such as**  **amm**

### onium **nitrate, that**  **potentially could**  **contribute to**  **visibility impairment**  **at certain**  **2 Regional**  **Haze Regulations**  **and Guidelines**  **for BEST**  **Available Retrofit**  **Technology (BART Detenninations,** **Fed. Reg.**  **vol. 70,** **page 39127** **Mr. Gregory**  **Nudd May**  **10, 2013**  **Page 5**  

### Class **I areas.**  **Therefore, the**  **background ammonia**  **concentration used**  **in visibility**  **modeling is**  **critical because**  **amm**

### onia **is a**  **precursor to**  **particulate ammonium**  **nitrate. The**  

### draft **BART report**  **used a**  **default value**  **of 1**  **ppb for**  **ammonia background**  **concentration for**  **all months**  **of the**  **year. This**  **value tends**  **to overestimate**  **the visibility**  **benefits associated**  **with reductions**  **of NOx,**  **particularly in**  **the winter**  **months. Therefore,**  **in their**  **analysis, AECOM**  **used amm** 

### onia **background concentrations**  **that were**  **taken from**  **actual data**  **from the**  **IMPROVE monitoring network.**  **In the**  **prepublication version**  **of the**  **EPA proposed**  **rule to**  **approve additional**  **portions of**  **Arizona's SIP**  **for Regional**  **Haze, received**  **by EPA**  **on May**  **9, 2013,**  **EPA acknowledges**  **the value**  **of considering**  **monitored IMPROVE**  **data "in**  **support of** 
**... RH**  

### planning **efforts"(p. 23).**  **Likewise, EPA**  **should recognize**  **the value**  **of monitored**  **data in**  **visibility modeling**  **for BART.**  **Recently, the**  **IMPROVE monitoring**  **network began**  **to incorporate routine measurements**  **of gaseous**  **amm**

### onia **at specific**  **sites. Data**  **from the**  **IMPROVE network**  **includes monthly**  **amm**

### onia **measurements at**  **several sites,**  **including one**  **in southern**  **Arizona (Chiricahua).**  **A review**  **of the**  **measurements taken**  **to date**  **at this**  **site (see**  **Fig. 4-1,**  **Attachment D)**  **indicates that**  **amm**

### onia **concentrations below**  **1 ppb**  **(e.g., 0.5**  **ppb) are**  **present at**  **this site**  **in winter.**  **Use of**  **those values**  **will more**  **accurately predict**  **the visibility**  **improvements expected**  **from the addition**  **of BART**  **controls for**  **NOx. Stack**  **Parameters The**  

### draft **BART report**  **identified the**  **data source**  **for stack**  **parameters as**  **being the**  **National Emission**  **Inventory 2008,**  **Version 2.**  **To assist**  **in determining**  **if the**  **reported values**  **for stack**  **temperature and**  **stack velocity**  **were appropriate**  **for use**  **in modeling,**  **TEP developed**  **a chart**  **for each**  **of these**  **parameters by**  **plotting actual**  **measured stack**  **temperature and**  **velocity versus**  **gross load.**  **Using these**  **charts, TEP**  **determined that**  **the value**  **for stack**  **velocity used**  **in the**  

### draft **BART report**  **(79 fils),**  **corresponded to**  **operation of**  **Sundt Unit**  **4 at**  **approximately 60%**  **of full**  **load (see**  **Attachment E).**  **The value**  **for stack**  **temperature used**  **in the**  

### draft **BART report**  **corresponded to**  **operation at**  **full load.**  **Since the**  **emission rate**  **used in**  **the modeling corresponds**  **to the**  **maximum daily average**  **hourly emissions**  **over a**  **period of**  **three consecutive**  **years, excluding**  **periods of**  **start-up, shutdQwn**  **and malfunction,**  **it is**  **reasonable to**  **assume that**  **those emissions would**  **correspond to**  **full load**  **operation. Therefore,**  **TEP provided**  **AECOM with**  **stack a**  **velocity value**  **associated with**  **full load**  **operation to**  **use in**  **their modeling.**  **Predicted Visibility**  **Improvement AECOM**  **modeled potential**  **visibility improvement**  **for two**  **different candidate BART**  **control options**  **that were**  **identified in**  **the** 

### draft **BART report:**  **1. Dry**  **Sorbent Injection**  **(DSI) I**  

### Selective **Non-Catalytic Reduction (SNCR)**  **2. Dry**  **Flue Gas**  **Desulphurization I**  

### Selective **Catalytic Reduction**  **For these**  **scenarios, AECOM**  **modeled visibility impairment**  **relative to**  **natural conditions**  **at the**  **Class I**  **areas within**  **300km of**  **Sundt Unit**  **4 and**  **found that**  **only Saguaro**  **National Mr.**  **Gregory Nudd**  **May 10,2013**  **Page 6**  

### Park **(East and**  **West) had**  **visibility impairment**  **in excess**  **of the**  **0.5 delta-dv**  **(see table**  **5.1, Attachment**  **D) "contribution"**  **limit established**  **by EPA.**  **Therefore the**  **AECOM analysis**  **concentrated solely**  **on this**  **Class I**  **area and**  **more specifically**  **on Saguaro**  **National Park**  **East. The**  **AECOM report**  **shows the**  **largest visibility**  **benefits at**  **the Saguaro**  **National Park**  **East for**  **the DSIISNCR**  **and DFGD/SCR**  **controls to**  **be 0.164**  **and 0.128**  **delta-dv, respectively.**  **It is**  **worth noting**  **that the**  **less stringent**  **emission control**  **option resulted**  **in greater**  **visibility improvement.**  **Using the**  **BMcD estimates**  **for annualized**  **costs, the**  **visibility cost**  **effectiveness for**  **these two**  **control scenarios**  **are: DSIISNCR**  **DFGD/SCR $** **38,000,000/dv $** **212,000,000/dv Each**  **of these**  **control scenarios**  **are considerably**  **more than**  **the benchmark**  **of $** **20 million**  **per deciview**  **that the**  **Federal Land**  **Managers previously**  **established a**  **as a**  **threshold above**  **which the**  **degree of**  **visibility improvements**  **is not**  **justified relative**  **to its**  **cost. Conclusion**  

### TEP **remains steadfast**  **in it**  **assertion that Sundt Unit**  **4 is**  **not BART-eligible.**  **However, EPA**  **appears to**  **be moving**  **forward with**  **a five-factor**  **BART analysis**  **for Unit**  **4, as**  **evidenced by**  **a** 

### draft **BA RT**  **report provided**  **to TEP**  **by EPA.**  **TEP hired industry**  **experts to**  **review the**  

### draft **BART report,**  **to develop**  **cost estimates**  **for the**  **control options**  **for S0** **2 and**  **NOx, and**  **to conduct**  **visibility modeling**  **for specific**  **control scenarios.**  **Based on**  **the cost**  **estimates, TEP**  **concludes that**  **three of**  **the five**  **technologies evaluated**  **(SCR, DFGD,**  **and WFGD)**  **significantly exceeded**  **the EPA's**  **screening cost**  **effectiveness threshold**  **of $** **5,000/ton, and**  **should therefore,**  **be determined**  **to be**  **not cost**  **effective as**  **BART. Based**  **on the**  **modeling, TEP**  **concludes that**  **each of**  **the two**  **control scenarios**  **evaluated exceeded**  **the Federal**  **Land Managers**  **visibility cost**  **effectiveness of**  **$ 20,000,000/dv,**  **and should**  **therefore, be**  **determined to**  **be not**  **cost effective.**  **If you**  **have any**  **questions regarding**  **the information**  **contained in**  **or attached**  **to this**  **letter, please**  **feel free**  **to contact**  **me. Sincerely,**  

# 4 **� Erik**  **Bakken Director,**  **Corporate Environmental**  **Services and**  **Land Management** **Mr. Gregory**  **Nudd May**  **10,2013 Page**  **7**



### Attachments **A TEP**  **Comments to**  **EPA Proposed**  **Approval/Disapproval of**  **the Regional**  **Haze SIP**  **for Arizona,**  **March 6,**  **2013 B**  **Sundt Unit**  **4-2011 Gross**  **Load C**  **Bums &**  

### McDonnell **Report- Tucson**  **Electric Power**  **Sundt Unit**  **4 BART**  **Review, May**  **9, 2012**  **D AECOM-**  **Visibility Improvement**  **Analysis for**  **Candidate BART**  **Control Options:**  **Sundt Unit**  **4, May**  **2013 E**  **Sundt Unit**  **4**
**-** 

### Plot **of Stack**  **Velocity versus**  **Gross Load** 

**Cc: Eric**  **Massey, ADEQ**  **Colleen McKaughan,**  **EPA Mark**  **Mansfield, TEP** 

# ATTACHMENT **A**

### March **6, 2013** 

**Gregory Nudd**  

## TUcson Electric**PowerCDmpan g**  **88 East**  **Broadway Blvd**  **(85701) Mail**  **Stop HQW602,**  **Post Office**  **Box 711**  **Tucson, Arizona**  **85702**

**Submitted via**  **Federal e-Rulemaking**  **Portal**



### United **States Environmental Protection**  **Agency Region**  **9, Air**  **Division (AIR.-2)**  **75 Hawthorne**  **Street San**  **Francisco, CA**  **94105 Telephone**  **(520) 918-8351**  **Email: EB**  **akk en@tep.com** 

**RE: EPA**  **Docket ID**  **No. EPA-R09** **-0AR-2012-0904 (77**  **FR 75704;**  **December 21,**  **2012)** 

### Dear **Mr. Nudd:**  **Tucson Electric**  **Power Company**  **(TEP), a**  **wholly-owned subsidiary**  **of UNS**  **Energy Corporation**  **(NYSE: UNS),**  **respectfully sub** **mits these**  **comments to**  **the Environmental**  **Protection Agency**  **(EPA) regarding**  **the Proposed**  **Rule; Partial**  **Approval and**  **Disapproval of** **Air Quality**  **Implement ation**  **Plans; Arizona;**  **Regional Haze**  **and Visibility**  **Impact s**  **of Transport,**  **Ozone and**  **Fine Part** **ic ulat**  **es** 

### ("Proposal"). **EPA issued**  **a supp**  **lemental notice**  **on February**  **4, 2013,**  **(78 FR**  

### 7702) **extending the**  **comment period**  **by 30**  **days to**  **March 6,**  **2013. TEP**  **owns and**  **operates electric**  **generation, transmission,**  **and distribution**  **assets that**  **safely and**  **reliably serve**  **more than**  **400,000 customers**  **with affordable**  **electricity in**  **Southern Arizona.**  **TEP owns**  **and operates**  **fossil-fired electricity**  **generating units**  **in Arizona,**  **including the**  **H.** 

### Wilson **Sundt Generating**  **Station. Actions considered**  **under EPA's**  **Proposal could**  **potentially subject**  **Unit 4**  **at this**  **facility to**  **emission limitations**  **under the**  **Regional Haze**  **Rule. 1**  **Therefore, EPA's**  **Proposal is**  **of great**  **importance to**  **TEP. Sundt**  **Unit 4**  **is not**  **BART eligible**  **In** 

### 2007, **while the**  **Arizona Department**  **of Environmental**  **Quality (ADEQ)**  **was developing**  **its Regional**  **Haze State**  **Implementation Plan**  **(SIP), TEP**  **provided information**  **to ADEQ**  **to assist**  **in determining**  **the BART**  **eligibility of**  **Irvington Generating**  **Station Unit**  **4. The**  **station has**  **since been**  **renamed as**  **the H.**  **Wilson Sundt**  **Generating Station**  **and will**  **be referred**  **to hereafter**  **as "Sundt".**  **The information TEP**  **provided, documents that Sundt Unit**  **4 underwent**  **"reconstruction" in**  **the 1980s**  **as part**  **of a**  **coal conversion**  **project, and was**  **therefore, not**  **"in existence"**  **on August**  **7, 1977**  **(one of**  **the requirements**  **for BART**  **eligibility). Using**  **that information,**  **ADEQ concluded**  **that 1**  **40 CFR**  **51.308**

**- Regional**  **haze program**  **requ irements** **EPA-R09 -0AR-** **201 2-0904**  **March 6,**  **201 3**  **Page 2**  

### Sundt **Unit 4**  **is not**  **a BART**  **eligible unit**  **and, therefore,**  **BART requirements**  **are not**  **applicable. On**  **March 2,**  **2011, ADEQ**  **submitted Arizona's**  **Regional Haze**  **SIP to**  **EPA, without BART**  **requirements for**  **Sundt Unit**  **4. On**  **November 22,**  **2011, TEP**  **received a**  **letter from**  **EPA (dated**  **November 17,**  **2011) stating**  **that EPA**  **was preparing**  **a Regional**  **Haze Federal**  **Implement ation**  **Plan** 

### (FIP) **for Arizona,**  **and would**  **"revisit" ADEQ's**  **decision regarding**  **the BART**  **eligibility of**  **Sundt Unit**  **4. On**  **March 16,**  **2012, TEP**  **received a**  **letter from**  **EPA, dated**  **March 14,**  **2012. This**  **letter explained**  **the basis**  **for EPA's**  **position regarding**  **BART eligibility**  **for Sundt**  **Unit 4.**  **EPA's justifications**  **for BART**  **eligibility is**  **premised on**  **the fact**  **that Congress**  **intended the**  **BART provisions to**  **apply to**  **sources which**  **had been 'grandfathered' from**  **new source**  **review permit**  **requirements, and**  **Sundt Unit**  **4 was**  **exempted from**  **new source**  **review at**  **the time**  **of the**  **reconstruction, therefore,**  **the unit**  **is BART**  **eligible. On**  **April 18,**  **2012, Hunton**  **and Williams,**  **on behalf**  **of TEP**  **submitt ed**  **a letter**  **to EPA**  **in response**  **to the**  **March 14**  **letter, providing**  **a detailed**  **legal framework supporting**  **TEP's and ADEQ's position**  **that Sundt Unit**  **4 is**  **not "BART**  **eligible". That**  **letter is**  **attached and**  **hereby incorporated**  **into these**  **comments. In**  

### the **Proposal, EPA**  **accepts TEP's**  **and ADEQ's**  **assertion that**  **the coal**  **conversion project**  **qualified as**  **a "reconstruction" under**  **the Regional**  **Haze Rule.**  **However, EPA**  **concludes that**  **"the Uni** **t remains**  **BART -eligible**  **because it**  **did not**  **go through**  **NSR/PSD permitt** **ing" [77**  **FR** 

### 75722]. **The Proposal**  **footnotes an**  **internal EPA**  **memorandum [77**  **FR** 

### 75722 **footnote 97]**  **that provides**  **additional detail**  **regarding EPA's**  **view of**  **BART eligibility**  **for Sundt Unit**  **4. In**  

### this **memorandum, EPA**  **states that**  **the exemption**  **from BART for**  **sources reconstructed**  **after August**  **1977, "is**  **introduced in**  **the BART**  **Guidelines" [40**  **C.F. R.**  **Part 51**  **App. Y**  **(hereinafter "Appendix**  **Y")], however, EPA**  **claims that Appendix**  **Y is**  **"not binding**  **with respect**  **to TEP Sundt**  **Unit 4**  **because it**  **is not**  **part of**  **a fossil**  **fuel-fired electric**  **generating plant with**  **a total**  **generating capacity in**  **excess of**  **750 MW".**  **While Appendix Y**  **is not**  **binding on Arizona**  **with respect**  **to Sundt**  **Unit 4,**  **in providing**  **the guidance**  **EPA did**  **"encourage States to follow the**  **guidelines for**  **all source**  **categories" in**  **order to**  **address "concerns**  **about equitable**  **application of**  **the BART**  **requirement to**  **source owners with similar**  **sources in**  **different States"**  **[70 FR**  **39108]. As**  **a federal**  **agency, EPA**  **must apply the**  **Regional Haze**  **Rule consistently**  **across states**  **and the**  **guidelines are**  **the means by**  **which EPA**  **itself, intends**  **to ensure**  **that consistency**  **is maintained.**  **For EPA to claim it can ignore**  **these guidelines,**  **in its evaluation**  **of a**  **particular state's**  **SIP, is**  **arbitrary and**  **capricious. Furthermore,**  **EPA's explicit**  **preference for**  **states to**  **apply Appendix**  **Y to**  **all source**  **categories is**  **in direct**  **conflict with**  **EPA's conclusion**  **that the**  **State of**  **Arizona was**  **incorrect in**  **applying those**  **guidelines, as**  **it did, with**  **respect to**  **BART eligibility**  **of Sundt**  **Unit 4.** **EPA-R09- 0AR-201**  **2-0904 March**  **6, 2013**  **Page 3**  

### Appendix **Y expressly**  **provides that**  **any** 

### emissions **unit for**  **which a reconstruction**  **"commenced" after**  **August 7,**  **1977,** 

### is **not BART**  

### eligibli, **and contains**  **no exceptions**  **or qualifications**  **to this broad**  **exemption. Footnote**  **9 in**  **the preamble**  **to the**  **BART Guidelines** **3 ,**  **referenced in**  **the internal**  **EPA memorandum,**  **is not**  **to the**  **contrary, as**  **it merely reflects**  **the reality that post-1977**  **source reconstructions,**  **in general,**  **would have**  **gone through**  **NSRIPSD permitting.**  **That footnote**  **does not,**  **nor could**  **it contradict**  **the plain, unqualified language**  **of EPA's**  **rule text**  **that exempts**  **"any" post-1977**  **reconstruction. In**  **the context**  **of the**  **Clean Air**  **Act the**  **word "any"**  **has an**  **expansive meaning.**  **Likewise, while**  **the preamble**  **statement observing**  **that BART**  **was intended**  **to "apply**  **to sources which had**  **been 'grandfathered"'**  **from NSR**  **permitting requirements** **4 is**  **generally true,**  **it does**  **not follow**  **that BART**  **applies either**  **to all**  **"grandfathered" sources**  **(it does**  **not apply,**  **for example,**  **to sources**  **that were**  **in operation**  **before 1962)**  **or to**  **sources, like**  **Sundt Unit**  **4, that**  **were not**  **grandfathered but**  **instead were**  **exempt from**  **NSR permitting**  **requirements as**  **a result**  **of a**  **mandatory coal**  **conversion pursuant**  **to a**  **Department of**  **Energy Order**  **under Section**  **301(c) of**  **the Power**  **Plant and**  **Industrial Fuel**  **Act of**  **1978 (which**  **superseded Sections**  **2(a) and**  

### (b) **of the**  **Energy Supply**  **and Environmental**  **Coordination Act**  **of 1974)** **5**

**. EPA**  **has failed**  **to consider**  **Congresses intent**  **with respect**  **to this**  **law. For**  **the foregoing reasons,**  **we believe**  **it is**  **clear that**  **Sundt Unit**  **4 is**  **not BART**  **eligible. Additional**  **Controls are**  **not Required**  **on Springerville**  **Units 1**  **and 2**  **or Sundt**  **Units 1-3**  **to Meet**  **Reason able**  **Progress Goals**  

### The **Proposal includes**  **a reasonable**  **progress analysis**  **with respect**  **to S02**  **emissions on**  **certain non-BART**  **eligible sources**  **including Springerville**  **Generating Station**  **("Springerville") Units**  **1 and**  **2 and**  **Sundt Units**  **1-3 [77 FR**  

### 75729]. **In each**  **of these**  **cases, EPA**  **concluded that**  **"it is**  **not reasonable**  **to require**  **additional S02**  **controls" [77**  **FR** 

### 75730]. **TEP agrees**  **with EPA's**  **conclusion. Springerville**  **Units 1**  **and 2**  **are equipped**  **with spmy**  **dryer absorbers**  **(SDAs) for**  **S02 control,**  **which operate**  **at greater**  **than 90-percent**  **control efficiency.**  **Furthermore, the**  **SDAs for both**  **units were**  **upgraded as**  **recently as**  **2006, which reduced**  **the emission**  **rate from**  **these units to**  **between 0.17 and**  **0.26 lbs** **!MM Btu**  **on an**  **annual average**  **basis. EPA's**  **estimate of**  **$17,000 to**  **$22,000 per**  **ton to**  **install additional**  **controls of**  **is far**  **beyond any**  **reasonable threshold**  **for cost**  **effectiveness. EPA**  **used an**  **initial screening**  **level of**  **$5,000 per**  **ton to**  **gauge cost**  **effectiveness [77**  **FR** 

### 75729]. **Note that**  **TEP believes**  **that a**  **cost per**  **ton of**  **pollutant removed**  **below this**  **level could**  **very well**  **be not**  **cost effective,**  **and we**  **encourage EPA**  **to refrain**  **from applying**  **a generalized**  **cost effectiveness**  **threshold. Cost**  **effe ctiveness**  **should be**  **considered site**  **specifically and**  **be weighed**  **in reference**  **to the**  **2 40**  **C.F.R. Part**  **51 App.**  **Y §**  **II.A. 2**  **(emphases added)**  **3 70**  **FR 39111**  **4 70**  **Fed. Reg.**  **at 39111**  **5 see**  **40 C.F.R**  **§ 52.2**  **1(b)( 2)(iii)(b).** **EPA-R09-0AR-2012-0904 March 6,**  **2013 Page4**  **other factors.**  **Sundt Units**  

### 1-3 **bum pipeline**  **natural gas,**  **and EPA**  **correctly points**  **out that**  **"there are**  **no cost**  **effective controls"**  **for such**  **units. For**  **point sources**  **of NOx,**  **EPA proposes**  **to disapprove Arizona's finding that**  **it is**  **not reasonable**  **to require**  **additional controls**  **on non-BART**  **eligible point**  **sources, because,**  **in EPA's**  **view, Arizona**  **did not**  **perform a**  **thorough analysis.**  **TEP believes**  **that EPA's**  **proper course**  **of action**  **should be**  **to work**  **with, and**  **support the**  **state in**  **developing the**  **analysis required for**  **the evaluation**  **of additional**  **NOx controls**  **on non-BART**  **eligible sources.**  **It is**  **TEP's understanding**  **that ADEQ**  **is interested**  **in addressing**  **EPA's concerns**  **about the**  **adequacy of**  **the analyses**  **in their**  **SIP, and**  **therefore, it**  **is premature**  **for EPA**  **to disapprove**  **of the**  **state's finding.**  **If you**  **have any**  **questio ns**  **regarding these**  **comments, please feel**  **free to**  **contact me.**  **Sincerely,** 

# ��
**Erik Bakken**  **Director, Corporate Environmental Services**  **and Land**  **Management**
**encl.**
**cc: Mark**  **Mansfield, TEP** 

**Phil Dion,**  **TEP Eric Massey, ADEQ** 

# HuNToN**&**

**WILUAMS**

**April 18,** **2012 Privileged**  **and Confidential**  **Attorney Work**  **Product**



### Colleen **McK aughan**  **Associate Director, Air**  **Division United**  **States Environmental Protection**  **Agency Region**  **IX** 

### 75 **Hawthorne Street**  **San Francisco,**  **CA 94105** 
**Dear Ms.**  **McK aughan:**  **HUNTON &**  **WILLIAMS LLP**  **2200 PENNSYLVANIA**  **AVENUE, NW**  **WASHINGTON, D.C.**  **20037-1701**
**TEL 202**  **• 955**  **• 1500**  **FAX 202**  **• 778**  **• 2201** 

**HENRY V.**  **NICKEL DIRECT**  **DIAL: 202**  **• 955**  **• 1561**  **EMAIL: bnickel@hunton.com**  **ALE NO:**  **37552. 000007** 



### We **have been**  **requested to**  **respond to**  **your letter**  **of March**  **14, 20**  **12, to**  **Jeffrey Yockey**  **regarding the**  **BART-eligibility status**  **of Unit**  **4 ofTEP's**  **Sundt Generating**  **Station under**  **the visibility**  **program of**  **the Clean**  **Air Act**  **("CAA"). TEP**  **appreciates your**  **interest in**  **understanding the**  **arguments that**  **TEP intends**  **to pursue**  **in this**  **matter. This**  **response supplements**  **the March**  **16, 20**  **11 email**  **from Mr.**  

### Yockey **to Francisco**  **Donez addressing**  **this issue**  **and providing**  **data regarding**  **Unit 4's**  **emissions, information on**  **stack parameters**  **for Unit**  **4, and screening-level**  **cost estimates**  **for various**  **categories of**  **emission controls.**  **We appreciate**  **EPA's recogniti** **on, as**  **stated in**  **your letter,**  **that the**  **text ofEPA's**  **BART** 

### Guidelines,**which are**  **codified rules**  **at 40**  **C.F.R. Part**  **51 App.**  **Y (hereinafter**  **"Appendix** 

### Y") **and thus**  **are binding**  **on EPA,**  **expressly provide**  **that** 

### "**any emissions**  **unit for**  **which a**  **reconstruction 'commenced'**  **after August**  **7, 1977,**  

### is **not BART-eligible."**  **40 C.F.R.**  **Part 51**  **App. Y**  

### § **ll.A.2 (empha** **ses added).**  **There is**  **no dispute**  **that Sundt**  **Unit 4's**  **reconstruction commenced**  **after August**  **7, 1977.**  **Moreover, Appendix**  **Y contains**  **no exceptions**  **or qualifications**  **to the**  **broad exemption**  **established by**  **the rule**  **quoted above.**  **The footnote**  **in the**  **preamble to**  **the BART**  

### Guidel**ines that**  **you cite**  **is not**  **to the**  **contrary, as**  **it merely**  **reflects the**  **reality that**  **post- 1977**  **source reconstructions**  **in** 

### the **general run**  **of cases**  **would have**  **"gone through NSRIPSD**  **permittin g."**  **70 Fed.**  **Reg. 39**  **104, 39**  **111 n.9**  **(July 6,**  **2005). Nothing in**  **that footnote**  **does --**  **or**

**ATLANTA AUSTIN**  **BANGKOK BEUING**  **BRUSSELS CHARLOTIE**  **DALLAS HOUSTON LONDON LOS**  **ANGELES McLEAN**  **MIAMI NEW**  **YORK NORFOLK**  **RALEIGH RICHMOND**  **SAN FRANCISCO**  **TOKYO WASHINGTON**  **www.hunton.com**

# HuNToN&

**WILLIAMS**

**Ms. Colleen**  **McKaughan Aprill8,2012**  **Page 2** 
**could --**  **contradict the**  **plain, unqualified**  **language of**  **EPA's rule**  **text that**  **exempts "any"**  **post 1977**  **reconstruction. In**  **any event,**  **as EPA**  **is aware,** **"[i]n the**  **context of**  **the CAA,**  **'the word**  **"any'' has**  **an expansive**  **meaning.'"** 

### New **Jersey v.**  **EPA, 517 F.3d**  **574, 582**  **(D.C. Cir. 2008)**  **(quoting** 

### New **York v.**  **EPA, 443**  **F.3d 880,**  **885 (D.C.**  **Cir. 2006)).**  **Likewise, while**  **it is**  **generally true**  **that BART**  **was intended**  **to "apply**  **to sources**  **which had**  **been 'grandfathered'"**  **from NSR**  **permitting requirements,**  **70 Fed.**  **Reg. at**  **39111, it**  **does not**  **follow that**  **BART applies**  **either to**  **all "grandfathered"**  **sources (it**  **does not**  **apply, for**  **example, to sources**  **that were**  **in operation**  **before 1962)**  **or to**  **sources, like**  **Sundt Unit**  **4, that**  **were not**  **grandfathered but**  **instead were**  **exempt from**  **NSR permitting**  **requirements as**  **a result**  **of a**  **mandatory coal**  **conversion pursuant**  **to a**  **Department of**  **Energy Order**  **under Section**  **301 (c)**  **of the**  **Power Plant**  **and Industrial**  **Fuel Act**  **of 1978 (which**  **superseded Sections**  **2(a) and**  **(b) of**  **the Energy**  **Supply and**  **Environmental Coordination**  **Act of**  **1974),** 

### see **40 C.F.R**  

### § **52.21(b}(2)(iii)(b). (Because**  **this order**  **may have**  **been the**  **only one**  **of its**  **kind, a**  **broader precedent**  **is not**  **presented by**  **accepting TEP's**  **argument.) For**  **the foregoing**  **reasons, we**  **believe it**  **is clear**  **that Sundt**  **Unit 4**  **"is not**  **BART-eligible," 40**  **C.F.R. Part**  **51 App.**  **Y** 

### § **ll.A.2, and**  **thus cannot**  **be subject**  **to BART**  **requirements. While**  **TEP requests**  **that EPA**  **recons ider**  **its position**  **on the**  **BART-eligibility of**  **Sundt Unit**  **4, TEP**  **understands that**  **EPA may**  **decide to**  **evaluate BART**  **factors as**  **applied to**  **Unit 4**  **while considering**  **this request. If**  **EPA intends to**  **evaluate these**  **factors for**  **Unit 4,**  **EPA must provide**  **adequate time for development of**  **relevant information**  **and exchange**  **of that**  **information among**  **EPA, the**  **Arizona Department**  **of Environmental**  **Quality, and**  **TEP, including**  **information regarding**  **visibility modeling**  **and cost**  **evaluations of**  **alternative potential**  **BART emission**  **limits that**  **might be**  **considered for**  **the unit.**  **Unlike other**  **sources in**  **western states**  **that have**  **been evaluated**  **for BART**  **over the**  **last two**  **or more**  **years, Unit**  **4 has**  **not previously**  **been identified**  **as potentially**  **subject to**  **BART requirements.**  **Thus, in**  **contrast to**  **other cases**  **where potential**  **BART emission**  **limit determinations**  **have been**  **developed following**  **extensive study**  **and consultation,**  **such study**  **and consultation**  **have not**  **occurred with**  **respect to**  **Sundt Unit**  **4. Accordingly,**  **unless EPA**  **determines very soon** 

### (as **it should)**  **that Unit**  **4 is**  **not BART-eligible**  **-- or**  **that, even**  **if it**  **is, it**  **is not**  **subject to**  **BART --**  **TEP and**  **the State**  **of Arizona**  **should be**  **given an**  **opportunity to**  **provide information**  **and input**  **to EPA,**  **and to**  **react to**  **EPA's information,**  **views, and**  **conclusions, on**  **these matters.** 

# HuN'ION&

**WII1lAMS**

**Ms. Co11een**  **McKaughan April**  **18, 2012**  **Page3 Finally,**  **TEP does**  **not believe**  **the provision**  **of the**  **pending proposed district**  **court consent**  **decree that**  **would require**  **proposed EPA**  **action on**  **regional haze**  **implementation plan**  **requirements for**  **Arizona by**  **May 15,**  **2012, and**  **fmal EPA**  **action by**  **November 15,**  **2012, should**  **be adopted.**  **If, however,**  **the decree**  **is adopted**  **and those**  **dates are**  **not significantly**  **extended, then**  **the decree**  **should be**  **revi sed**  **to exclude**  **Sundt Unit**  **4 from**  **that provision's**  **coverage, with**  **later dates**  **establish**

**ed for**  **Unit 4**  **that would allow**  **for resolution**  **of the**  **BART -eligibility**  **issue (and**  **the "subject**  **to BART''**  **issue) for**  **Unit 4**  **and development**  **of necessary**  **BART-related information**  **with respect**  **to the**  **unit. We**  **would be**  **happy to**  **discuss these**  **matters with**  **you further**  **at your**  **convenience.** 

# I�

**cc: ,**  **EPA Region**  **IX**

**ric Mass**  **, Arizona**  **Department of**  **Environmental Quality**  **Marc Jerden,**  **Esquire, TEP**  **Erik Bakken,**  **TEP Jeffrey**  

### G. **Yock ey,**  **P.E., TEP** 

# ATTACHMENT **B**

## � **�** 

### - **Sundt Unit**  **4** 

### - **2011** 

### Gross **Load**

**1 4 0** **�-------------------------------------------------------------------------------------------------------------------------------,**

**1 2 0**  

### I**I •**  ***** **...** 

### I W Jl II **• ..,**  

### I I **..,** 

### H I **I**

**1 0 0**  

### ...... '"' liM! **...** 

### � J:

**80** 

## -g **60 0**  **...J**

**40**

**20** 

### II **I I J. IJ. I I I I I II**  **U. • I I I I** 

**o** 

### " I W**,' 01**  **/ 01**  **/1 1** **I** 

### • ' .. **I** 

### � **I ....-.**  **I I I**  **I 02/20** **/1 1**  **04/1 1 /** **11 05/** **31 /1**  **1 07/20/** **11 09/08** **/1 1**  **1 0 /28/1**  **1 1 2** **/1 7/1**  **1 Date** 

# ATTACHMENT **C**

### May 

### 9, **20 13** 

**Mr**
**. Jef**  **f rey**  **G.** 

### Yockey, **P. E.**  **Manager, Corpo** **r ate**  **Environm ental**  **Se rvices**  **UniSou rc** **e Ener** **gy Cor** **por at**  **ion Mail**  **Stop HQ** **W6 02**  **88 E**  **Br oadway**  **Blvd Tusc** **an, AZ**  **85 70** **2- 07**  **11 Re**  **: Tucson**  **El e**  **ctr ic**  **Power Sundt**  **Unit 4**  

### BART **Re v i** **ew Dea** **r Mr.**  **Yock ey:**  **Burns &**  **McDonn ell**  **has per** **for med**  **a revi**  **ew of** **the dr** **aft Fiv** **e-F actor**  **BA RT**  **Analysis 1**  **for the**  **TEP Sundt**  **Sta tion Unit**  **4** 

### that was **pr epared**  **fo r**  **US EPA**  **Re gion**  

### 9 **and issued**  **Octob er**  

### 9, **20 12.**  **Our analysis**  **revi ewed**  **the capital**  **and oper** **ating costs**  **for each**  **te chnology**  **and identified**  **dif f**  **erences betwee**  **n ou** **r es** **ti mate**  **and the**  **es ti**  **mate s**  **prepa red**  **for Re** **gion** 

### 9. **Bu rns**  **& McDonn** **e l l's**  **estima te**  **of the**  **cont rol**  **costs was**  **hi gher**  **for all**  **te chnol**  **ogy applications**  **than the**  **es tima** **te s**  **pr epa** **red for**  **Re gion**  

### 9. **The es** **ti mate**  **d removal**  **costs per**  **ton by**  **cont rol**  **te chnol**  **ogy are**  **sum mar** **ized in**  **Table No.**  **I.** 

### Table **No. 1**  **Control Cost Estimate**  **Summary**
**Region 9**  

### BART **BMcD Estimates**  **Estimates NOx**  **Control Technology**  **Selective Non-Catalytic**  **Reduction (S**  **NCR) $**  **3,295** 

### $ **3,637** 

### Selective Catalytic **Reduction (SCR)**  **$ 4,874**  

### $ **7,874** 

### S02 **Control Te**  **chnology Dry**  **Sorbent Injection**  **$ 1,826**  

### $ **3,088** 

### Dry **FGD $**  **6,434** 

### $ **9,359** 

### Wet **FGD $**  **6,957** 

### $ **8,229**

**Note: Atf**  **values are**  **in $/ton**  **of pollutant**  **removed**

**1 Technical**  **Analysis for**  **Arizona and**  **Hawaii Regional**  **Haze FIPs:**  **Task 7:**  **Five-Fac tor**  **BART Analysis**  **for TEP**  **Sundt (Irvington),**  **Contract No.**  **EP-D- 07-102,**  **Work Assignment**  **5-12, Version 1,**  **October 9,** **2012**
**9400 Word** **Parkway •**  **Kansas (ify,**  **Missouri 64114-JJ/9**  **Tel: 816-JJJ-9400**  **• fox.·**  **816-JJJ-3690 •**  **www.hurnsmcd.com**

### May **9, 201**  **3**

**Page 2** 
**The estimates**  **prepa re**  **d for**  **Region 9**  **were based**  **on average**  **inlet po**  **llu tant**  **loadings for**  **20 1**  **1. The**  **201 1**  **data is**  **a good**  **ba sis**  **as Unit**  **4 was**  **operated on**  **coal for**  **a large**  **perc entage**  **of the**  **time. Howeve** **r, the**  **EPA analysis**  **assumes a**  **Uni t 4**  **gr oss**  **generating capac**  **ity of**  **17 3 .**  **3 MW.**  **This is**  **the unit's**  **gr oss**  **gene ra** **ting cap** **ab il**  **ity on**  **natur al**  **gas. The**  **unit cannot**  **re ach**  **this load**  **wh ile**  **fir ing**  **coal. The unit**  **is limi** **ted to**  **app ro** **x imately**  **130 MW**  **when fir** **ing coal**
**. The**  **EPA analysis**  **dete rmin** **ed a capacity**  **fa ctor**  **for the**  **unit of0**  **.37 based**  **on the**  **capab il**  **ity of**  **Unit 4**  **to achieve**  **1 7 3 .**  **3 MW on**  **natur al**  **gas. A**  **more appr** **opr ia** **te ca** **pac ity**  **fa ctor**  **, using**  **a 1 3**  **0 MW**  **gr oss**  **generating capab**  **il ity**  **wh ile**  **fir ing**  **coal, is**  **0 . 49**  **based on the**  **20 11**  **data. (Please**  **note that**  **although the**  **calcu lated**  **capacity fa** **ctor is**  **dif fer** **ent, the**  **annual emissi** **ons in**  **tons per**  **yea r**  **removed do**  **not necessa** **ril y**  **change si** **gnificantly. The**  **change in**  **capacity fa** **ctor is la** **rgely offset**  **by the change**  **in maximum**  **unit gr** **oss ra** **ting.) Fol**  **lowing is**  **a sum**  **mary of**  **the cost**  **estimates for**  **each technolog** **y that**  **was evalua**  **ted in**  **the report**  **pr epared**  **for Region**  **9 and**  **a dis** **cussion of**  **the re** **asons for**  **the dif**  **fer ences**  **fr om**  **the Burns**  **& McDonne**  **ll estimates.**  **NOx CO** **NTROL SYSTEMS**  **Sele ctive**  **Non-Ca talyt** 

**ic Reduction**  **CSNCR**

**) The**  **BART analysis**  **prepar ed**  **for Region**  **9 dete**  **rm ined**  **a NOx removal**  **cost to**  **be app** **ro xi**  **mate ly**  **$3300 per**  **ton for**  **inst allation,**  **operation and**  **maintenance of**  **a SNCR**  **system on**  **Unit 4.**  **Bu rns**  **& McDonne**  **ll 's**  **analysis ind**  **icated the**  **costs should**  **be hig** **her at**  **app ro** **xim ate**  **ly $3**  **640 per**  **ton of**  **N O x**  **re moved**  **(based on**  **201 1**  **operating data)** 
**. The**  **re sults**  **of these**  **analyses ar** **e pr** **ov ided**  **in Table**  **No. 2.** 

**2**

### May **9, 201**  **3**

**Pag e 3** 

**Table No.**  **2 SNCR**  **Cost Comparison** 
**Capacity Factor**  **Control Efficiency**  

### U n **controlled Rate**  **NOx Rate**  **lbs/hr NOx**  **Rate lbs/mmBtu**  **NOx (tpy)**  

### Controlled **NOx Rate**  **(lbs/hr@ rated load)**  **NOx Rate**  **(lbs/mmBtu) NOx**  **(tpy) NOx**  

### Removed **(tpy) Costs**  **Fixed O&M**  **$ Variable**  **O&M (**  **$) Total O&M**  **( $**  **) Capital**  **Cost Capital**  **Cost (annualized)**  **Total Annual**  **Cost Cost**  **($/ton Nox**  **Removed)** 

### BART **Report 0.37**  **30% 813**  **0.445 1318**  **569 0.31**  **923 395**  **97,048 842,550**  **939,598 3,446,000**  **361,850 1,301,448**  **3,295** 

### BMcD **Estimate 0.49**  **30% 610**  **0.445 1367**  **427 0.31**  **957 410**  **193,800 807,684**  **1,001,484 4,695,000**  **490,158 1,491,642**  **3,637** 

### There **are seve** **ral re** **asons fo**  **r the**  **dif f**  **er ence**  **in the**  **cost estima**  **te s.**  **These ar** **e summa** **rized below:** 

**•** 

### Capital **Co sts:**  **Diff er** **ences in**  **capital costs**  **is the**  **primar y**  **fa ctor**  **that influenced**  **the ov**  **er all**  **es timat** **es. Burns**  **& McDonn** **ell's es** **ti ma** **te of**  **the ins** **talled SN**  **CR costs**  **was appro**  **xima t** **ely 35**  **pe rcent**  **hig her**  **than the**  **estima te**  **pr epar** **ed fo**  **r the EPA.**  **Ther e**  **ar e**  **seve ral**  **re asons**  **that the**  **cos ts**  **es tima**  **te d**  **fo r the**  **EPA are**  **lo wer:**  **•**

**o** 

### The **EPA es** **tima te**  **incl ud** **es onl**  **y $1**  **7/k w**  **fo r the SNCR**  **and bal** **ance of**  **pla nt**  **costs. This**  **is low** **er than**  **the $1**  **8 /** **kw than was**  **provided in**  **the Int** **eg rate** **d Pla** **nning Mod e l**  **{IPM) re**  **por e**  **which is**  **re f**  **e r en** **ced in the**  **Fiv e-Fa** **ctor BA** **RT analysis**  **as the**  **basis fo**  **r the**  **es ti**  **mate.**
**2 Documentation**  **for EPA Base**  **Case v.4.10**  **Using the**  **Integrated Planning**  **Model, United**  **States Environmental**  **Protection Agency,**  **Air and**  **Radiation, EPA**  

### @ **430RIOOI 0,**  **August 2010** 

**3**

### May **9, 2013** 

**Page 4** 

**o** 

### The **IPM report**  **cos ts**  **are in**  **2010 dol**  **lars and**  **need to**  **be esca**  **lated to the**  **current**

**year. These**  **adjustments would**  **add approx**  **ima te**  **ly $4** **00,000 to**  **the estimated**  **capital cost.**  **o** 

### The **fa ctors**  **used to**  **account fo**  **r engineering**  **and other issues**  **appear low in the Region**  **9 es** **ti mate.**  **For examp** **le, the**  **estima te**  **inclu ded**  **only 5**  **percent total**  **fo r**  **engineering and**  **construction management.**  **Th is**  **is fa** **r below**  **the values**  **lis ted in**  **the ref**  **erenced IPM**  **manual. The**  **engineering and**  **cons truction**  **management costs**  **should be**  **in the**  **20 percent**  **range. Adjusting**  **fo r**  **this issue would add approx**  **imately $500,000**  **to the**  **estima te.**  **o** 

### The **EPA es** **tima te**  **assumed that**  **a removal**  **of 30**  **percent can be**  **maintained with**  **an SNCR.**  **Continually achieving**  **this hi** **gh removal**  **efficiency requires**  **the ins** **tal lation of**  **multiple SNCR**  **spray levels**  **and the associa** **ted piping**  **and controls**  **to al**  **low fo**  **r variations**  **in unit**  **operation and**  **load. The**  **urea must**  **be sprayed**  **into the**  **appropriate temperature**  **zone in**  **the steam**  **gener ator**  **to achieve**  **satisf actory**  **per f**  **ormance. Inst** **all ing**  **multiple spray**  **levels adds**  **signi ficantly**  **to the**  **SNCR cos** **ts. •** 

**•** 

### Fixed **Operating &**  **Maintenance Co**  **sts: The**  **fixed operating**  **costs in**  **the estima** **te prepared**  **fo r**  **Region 9**  **inclu ded**  **onl y**  **$97,000 fo** **r annual**  **O&M. Most**  **of this**  **cost was**  **fo r**  **additional opera** **tions personnel.**  **This estim** **ate is**  **not adeq** **uate fo** **r a system that**  **inclu des**  **silos unlo** **ading equipmen** **t, transfer**  **and di**  **stribution equipment,**  **numerous control**  **valves and**  **multiple injection**  **levels. The**  **main tenance**  **costs should**  **be at**  **least 2**  **percent of**  **the capital**  **costs which**  **adds approxi**  **mate ly**  **$100,000 to**  **the fixed O&M**  **costs. •**  

### Variable **Opera tin**  **g Co** **sts: The**  **variable operating**  **costs were**  **reasonab ly**  **close between**  **the estimates.** 
**NOx CONTROLSYSTEMS**  **Sele ctive**  **Catalytic Reduction**  **(SCR) The**  **estimates to**  **install and**  **ope rate**  **an SCR**  **system on**  **Sundt Unit 4**  **were substan** **tially dif**  **fe rent.**  **The es** **ti mate**  **prepared fo**  **r Region**  **9 was**  **approx imately**  **$4 900**  **per ton**  **ofNOx removed.**  **Bu rns**  **& McDonn** **ell's estimate**  **was approx**  **imately $7900 per**  **ton removed.**  **A summ** **ary of**  **the estimates is**  **provided in**  **Tab le**  **No. 3.** 

**4**

### May **9, 201**  **3**

**Page 5**

**Table No.**  **3 SCR**  **Cost Comparison** 

**BART Report**  

### Ca **pacity Factor 0.37**  **Control Efficiency**  **89% Uncontrolled**  **Rate** 

### NOx **Rate lbs/hr**  **813 NOx**  **Rate lbs/mmBtu**  **0.445 NOx**  **(tpy) 1318**  **Controlled Emissions**  

### NOx **Rate (lbs/hr@**  **rated load)**  **91 NOx**  **Rate (lbs/mmBtu)**  **0.05 NOx**  **(tpy) 148**  **NOx Removed**  **(tpy)** 

### 1170 **Costs** 

### Fixed **O&M $**  **362,000 Variabl**  **e O&M**  **($) 1,376,165**  **Total O&M**  **($) 1,738,165**  **Capi tal**  **Cost 37,970,000**  **Capi tal**  **Cost (annualized)**  **3,964,068 Total**  **Annual Cost**  **5,702,233 Cost**  **($/ton Nox**  **Removed) 4,874**  **BMcD Estimate**  

### 0.49 **89% 610**  **0.445 1367**  **67 0.05**  **150 1217**  **739,200 935,000**  **1,674,200 75,720,000**  **7,905,168 9,579,368**  **7,874**


### The **dif f**  **erence in**  **the estima** **ted capital**  **costs was**  **the primar** **y fa** **ctor that**  **influenced the**  **costs to remove**  **a ton**  **of NOx.**  **Bur ns**  **& McDon** **ne ll**  **bel ieves**  **this dif**  **f erence**  **in estima** **ted capital**  **costs is because**  **the esti**  **mate prepared**  **fo r**  **the EPA did**  **not take**  **into account**  **the extre** **me diffic** **ulty of**  **inst all**  **ing an**  **SCR on**  **Unit 4**  **given site**  **specific fa** **ctors (The**  **EPA esti**  **mate used**  **a capital**  **costs retrofit**  **fa ctor**  **of 1.0). The**  **Sun dt**  **fa c**  **il ity**  **is extre** **mely congested**  **and substantial**  **additional cos** **ts will**  **be incur** **red with**  **the installa** 

**tion of**  **an SCR**  **fo r**  **the unit.**  **Even the**  **fe as**  **ibili ty**  **of ins** **t al**  **li ng**  **an SCR**  **on Sundt**  **4 is**  **ques tionab**  **le. An**  **exte nsive**  **study will**  **be requir** **ed to**  **eval uate**  **the fe** **as ibil**  **ity of**  **ins t** **all ing**  **SCR bef**  **ore a**  **final decision**  **regard ing**  **the technology**  **can be made.** 

**5 •** 

### May **9, 201**  **3**

**Page 6 •** 



### Potent **ial options**  **that could**  **be cons**  **idered fo**  **r the**  **SCR include**  **inst alli** **ng the**  **SCR in a "t** **ailend" con** **figuration or**  **replacing the exis** **ting air**  **heaters. However,**  **both of**  **these solu** **tions would be**  **sub stant** **ially more**  **expen sive**  **than any**  **of the**  **estima tes**  **provided in**  **this report.**  **Some of**  **the fa** **ctors that**  **make the**  **SCR inst** **alla tion**  **extr emely**  **di ffi**  **cult include:** 

**•** 

### An **SCR cannot**  **be ins** **t al**  **led in a**  **truss arrangement**  **above the air**  **heater (the**  **common SCR**  **retrofit configur** 

**ation) due**  **to the exis** **ting boiler**  **structure and**  **interf erences**  **with the**  **existing coal**  **handling syste** **m. •**  

### The **exiting Unit 4**  **air heater**  **is a**  **horizontal shaft**  **configuration lo** **cated at**  **a very low**  **elevation. The**  **du ctwork**  **fr om**  **the economizer**  **outlet to**  **the air**  **heater is**  **completely encom** **passed by**  **boile r**  **steel and**  **other structu**  **res. This**  **makes routing**  **duct work**  **fr om**  **the economizer**  **outlet to**  **the SCR and**  **back to**  **the air heater**  **inlet (as**  **would be**  **requir ed**  **with a**  **"side-saddle" SCR**  **arrangeme nt)**  **very di**  **ffi cult**  **or imp** **ossible. Exhibit**  **1 shows the**  **congestion in**  **this area.**  **•** 

### Mate**rial hand**  **lin g**  **syste ms**  **(primarily coal**  **handling )**  **completely blo** **ck the**  **air heater area**  **on three**  **sides of**  **Unit 4**  **and part**  **ially blocks**  **the area**  **on the**  **fo urth**  **side. The**  **material handling**  **systems cannot**  **be rel**  **ocated due**  **to site**  **constraints. The**  **material handling**  **systems inter** **fe rence**  **greatly compl**  **icates locating**  **the SCR**  **and routing**  **duct work**  **to and fr** **om the SCR.**  **•** 

### The Unit 3 **circulating water**  **lin es**  **run adjacent**  **to the**  **no rth**  **side of**  **the Unit**  **4 boiler**  **area where**  **it appears**  **an SCR**  **could be**  **located. Consequently,**  **the SCR**  **wi ll**  **have to be**  **loca ted remote**  **fr om**  **the unit**  **adding subs** **tan tia**  **ll y**  **to the**  **SCR costs.**  **Exh ibit**  **2 illus** **trate s**  **the impact the Uni** **t 3 cir** **culating water**  **li nes**  **have on**  **the inst** **alla tion**  **of a**  **Unit 4**  **SCR.**
**The dif**  **f erence**  **in the**  **predicted control costs**  **prepared fo** **r Region**  **9 and those**  **prepared by**  **Burns &**  **McDon nell**  **is 34**  **percent. There are**  **sever al**  **reasons fo**  **r this**  **dif**

**f erence**  **which are**  **summarized below.**  **•** 

### Capital **Cos ts:**  **Burns &**  **McDonnel l's**  **esti mate**  **of the**  **capital costs**  **to install**  **SCR on**  **Unit 4**  **was approximate**  **ly twice**  **the esti**  **mates prepared**  **fo r**  **Region 9.**  **Items that**  **we believe**  **impact the**  **esti mated**  **costs inclu** **de: o**  

### The **Region 9**  **esti mate**  **used a retrofit**  **fa ctor**  **of 1 .**  **0 fo** **r the**  **SCR installation.**  **As discussed**  **above, the**  **inst al**  **lation of an SCR**  **on Sundt**  **Unit 4**  **would be extre** **mely di**  **ffi cult**  **if it**  **is even**  **fe asible.**  **The area**  **around the**  **Unit 4**  **boiler is very**  **conges ted**  **with ductwork,**  **coal hand**  **li ng**  **equipmen t**  **and the fa** **bric filter.**  **The SCR**  **wi ll**  **have to**  **be lo**  **cated some**  **dis tance**  **away fr** **om the**  **air heater**  **gas inlet**  **requiring su** **bstantial additional**  **ductwor k**  **co mpared**  **to a**  **normal ins** **tal latio** **n. Equipmen** **t and**  **inst al**  **lation costs**  **to inst** **al l**  **an SCR**  **on the**  **unit will**  **be subs** **ta ntially**  **greater**

**6**

### May **9, 2013** 

**Page 7**
**than the**  **cap ital**  **cost estima** **te prepared fo** **r Region**  **9. Using**  **a retrofit**  **fa ctor**  **of I .**  **5**

**or higher**  **is appropria** 

**te fo**  **r this**  **app li** **cation. o**  

### The **EPA esti**  **mate did**  **not include**  **any costs**  **fo r**  **air heater**  **modifications. Subs** **tan tial**  **modific ations**  **to the**  **air heater**  **will be**  **needed to**  **accommoda te**  **SCR opera** **tion. The**  **minim um**  **modifications (soot** **blo wer**  **addition )**  **to the**  **air heater**  **would add**  **$ I -2**  **mil lio** **n to**  **the base**  **capital costs.**  **•**

**o** 

### The **estimated base SCR costs**  **pr epared**  **fo r**  **Region 9**  **seems low**  **and does**  **not appear**  **to take**  **into account**  **the size**  **of the**  **unit in**  **determ ining**  **the capital**  **costs. The**  **dir ect**  **capital cost**  **of $2**  **I6 per**  **kw fr** **om the**  **Region 9**  **esti mate**  **was only**  **sl ightly**  **mor e**  **than the**  **costs fo**  **r a 600**  **MW unit.**  **Indus try**  **experience is**  **that the**  **unit cost ($** **/kw) of**  **inst alli**  **ng an SCR on a**  **small unit**  **will be**  **much more**  **expen sive**  **than the**  **unit cost**  **of an**  **SCR installation**  **on a**  **large unit.**  **Ci chanowicz** **3 reported,**  **based on**  **a survey**  **of SCRs**  **inst al**  **led in**  **the 20**  **0 8 -20**  **I 0 time**  **fr ame,**  **the unit costs**  **fo r a**  **unit simi**  **lar in**  **size to**  **Sundt 4**  **would be**  **around $3**  **50 per**  **kw. Burns**  **& McDonne**  **ll's experience**  **in recent years**  **is that**  **dir ect**  **costs fo**  **r an**  **SCR on**  **a sm** **all unit**  **can easily**  **exceed $400**  **per kw (assuming**  **a nor** **mal retrofit**  **app li**  **cation). o**  

### The **cost es** **ti mate**  **is based**  **on the**  **IPM report**  **which is**  **in 20**  **IO dol**  **lars. The**  **capital costs**  **should be**  **escala**

**ted to**  **the cur** **rent date**  **which adds**  **appr oxima** **te ly**  **5-I 0**  **percent to**  **the costs.**  **o** 

### The **Region 9**  **esti mate**  **did not**  **inc! ude**  **Owner's costs.**  **Own er'**  **s costs**  **of at**  **le ast**  **5 percent**  **shou ld**  **be added.**  **•** 

### Fixed **Operating Co**  **sts: The**  **fixed operating**  **costs in**  **the esti**  **mate prepared**  **fo r**  **Region 9**  **inclu ded**  **appro xima** **tely $3**  **00 ,** **000 fo**  **r annual**  **maintenance. This**  **estima te**  **seems extre**  **mely low**  **fo r a**  **system of**  **t his**  **cost and**  **complexi ty.**  **Burns &**  **McDonne ll**  **believes this**  **cost should**  **be at**  **least I**  **percent of**  **t he**  **capital cost**  **which using**  **a realistic**  **capital cos** **t. Usin** **g a realistic percentage**  **wo uld**  **add appro xima** **tely $4** **00 ,0**  **00 per**  **year to**  **the fixed**  **operating cost estimate.**  **•** 

### Variable **Opera ting**  **Costs: Burns**  **& McDonne**  **ll's estima** **te fo**  **r the**  **variable operating**  **costs was**  **subs tan** **tially lower**  **than the**  **estima tes**  **prepared fo**  **r Region**  **9. This**  **appears to**  **be because**  **variable cost**  **estima te**  **fo r**  **Region 9**  **included a**  **high cost**  **fo r**  **catalyst disposal**  **(We assume**  **this cost also includes**  **replacement catalyst.)**  **The Region**  **9 esti**  **mate inc**  **lu ded**  **nearly $ 6**  **00 ,0** **00 per year**  **fo r**  **catalyst replacement.**  **A mor**  **e appropriate**  **average catalyst**  **replacement cost**  **would be**  **around $3**  **00 ,0**  **00 per**  **year fo**  **r Unit 4.** 

**3 Current Capital**  **Cost and**  **Cost -eff**  **ectiveness of**  **Power Plant**  **Emisss ions**  **Control Technologies,**  **J. Edward**  **Cichanowicz, Prepared**  **for Unitility**  **Air Regularoty Group,**  **January, 2010** 

**7**

### May **9, 2013** 

**Page 8** 
**SO &**  **CO NTROL** **SYSTEMS Dry**  **Sorbent In** **jection (D**  **SI) The**  **cos ts**  **to install**  **and ope rate**  **a DSI**  **system on**  **Unit 4**  **are sum**  **marized in**  **Table No.**  **4. The**  **projected cost**  **in the**  **estima tes**  **prepared fo** **r Region**  **9 was appro xima** **tely $1**  **800 per ton**  **of S02** 
**. Bur** **ns &**  **McDon ne**  **ll's esti**  **mate fo**  **r the**  **DSI costs**  **was appro** **ximately $3**  **100 per**  **ton removed.** 

**Table No.**  **4 DSI**  **Cost Comparison** 


### Capacity **Factor Control Efficiency**  **Uncontroll ed**  **Rate** 

### S01 **Rate lbs/hr**  **S01 Rate**  **lbs/mmBtu so2**  **(tpy) Controlled**  **Emissions** 

### S02 **Rate (lbs/hr**  **@ rated**  **load) S02**  **Rate (lbs/mmBtu)**  **S02 (tpy)**  **502 Removed**  **(t py)**  **Costs** 

### Fixed **O&M $**  **Variable O&M**  **($) Total**  **O&M ($**  **) Capital**  **Cost Capital**  **Cost (annualized)**  **Total Annual**  **Cost Cost**  **($/ton S02**  **Removed) BART**  **Report** 

### 0.37 **75% 1333**  **0.729 2160** 
**333 0.18**  **540 1620**  **164,000 2,342,289**  **2,506,289 4,332,000**  **452,261 2,958,550**  **1,826 BMcD**  **Estimate**



### 0.49 **70% 999**  **0.729 2160** 
**599 0.22**  **648 1512**  **238,600 3,701,000**  **3,939,600 6,980,000**  **728,712 4,668,312**  **3,088** 

### There **are a**  **vari ety**  **of reasons**  **fo r**  **the dif**  **fe rence**  **in the**  **cost estima** **tes. These**  **are summa** **rized bel**  **ow:**

**•** 

### S02 **Control Le** **vel :**  **The esti**  **mated removal**  **fo r**  **the Region**  **9 esti**  **mate was**  **75 percent.**  **This control level is**  **hi gh,**  **par ticularly**  **considering the**  **low capacity**  **fa ctor**  **fo r**  **the unit.** 

**8**

### May **9, 201**  **3**

**Page 9**

**We bel**  **ieve a**  **more appr** **opria te**  **S02 control**  **level would**  **be around**  **70 per** **cent fo**  **r DSI**  **on Unit**  **4. •**  

### Capital **Cos ts:**  **Bur ns**  **& McDonnel**  **l's esti**  **mate of**  **the inst** **al led**  **DSI costs**  **was app** **roximately twice**  **the estima** **te prepared fo**  **r the**  **EPA. It**  **appears the**  **basis fo**  **r the**  **esti mate**  **was an**  **arb itrary**  **$ 2 5/** **kw. While**  **this value**  **may be**  **appropria te**  **fo r**  **larger units,**  **the unit**  **costs ($** **/kw) would**  **be sign ificantly**  **higher fo**  **r a small**  **unit such**  **as Sundt**  **4. There**  **were a**  **fe w**  **additional issues**  **that would**  **impact the**  **capital costs**  **of inst** **al ling**  **a DSI**  **system: o**  

### The **Region 9**  **estima te**  **incl uded**  **only 5**  **percent fo**  **r engineering**  **and cons** **truction management**  **and no**  **Own er'**  **s cos** **ts. Appropriate**  **values would**  **add 15**  **to 20**  **percent to**  **the estima** **te. o**  

### The **costs did**  **not include**  **any balance**  **of pla** **nt costs. A DSI system**  **will require**  **ins trument**  **air and**  **oth er**  **services. o**  

### The **Sundt site is**  **ver y**  **conges ted.**  **It is**  **lik ely**  **the sorbent**  **sil os**  **wi ll**  **need to**  **be loca** **ted some**  **di stance**  **fr om**  **the injection**  **po int.**  **This will**  **add to the**  **capital costs**  **due to the**  **increased le**  **ngth of**  **transf er**  **piping. •** 

**•** 

### Fixed **Operati ng**  **Costs: The**  **fixed operating**  **costs in the**  **estima te prepared**  **fo r**  **Region 9**  **incl uded**  **only $3**  **6, 000**  **fo r**  **annual maintenance**  **material and**  **labor costs.**  **This value**  **is not**  **adeq uate**  **fo r a**  **DSI system**  **which includes**  **sil os,**  **transf er**  **blo wers,**  **piping and**  **valves, and**  **multiple injection**  **nozzles. A**  **cost of**  **at least**  **1- 2**  **percent of**  **the capital**  **costs should**  **be included**  **which would be**  **appr oximately**  **$100 ,**  **000**
**. •**  

### Variab **le Opera** **ting Cost** **s: Bu** **rns &**  **McDonn ell's**  **estima te**  **of the**  **variab le**  **operating costs is**  **approx ima** **te ly**  **$1 .3**  **milli on**  **higher than**  **the Region**  **9 esti**  **mate. The**  **Region 9**  **estima te**  **appears to**  **be based**  **on using**  **li me**  **as the**  **so rbent.**  **Burns &**  **McDonn ell's**  **estima te**  **is based**  **on using**  **a sodium**  **based sor** **bent. We**  **bel ieve**  **it is**  **more appropria** **te to**  **use a**  **sodium sorbent**  **considering the**  **high S02**  **removal leve**  **ls required**  **fo r**  **the project.**  **Dry FGD**  **The projected**  **cos ts**  **to inst** **al l**  **and ope**  **rate a**  **dry FGD**  **on Uni** **t 4 are summarized**  **in Table**  **No. 5.**  **Bu rns**  **& McDonn** **ell's cost**  **fo r**  **the dry**  **FGD (including**  **a new**  **fa bric**  **fil t** **er )**  **is appr** **oxi mately**  **45 percent**  **higher than**  **the esti**  **mates prepared**  **fo r**  **Region 9.** 

**9**

### May **9, 201**  **3**

**Page 10** 

**Table No.**  **5 Dry**  **FGD Cost**  **Comparison**

**BART Report**  

### Capacity **Factor 0.37**  **Control Efficiency**  **89% Uncontrolled**  **Rate** 

### 502 **Rate lbs/hr**  **1333 502**  **Rate lbs/mmBtu**  **0.729 502**  **(tpy) 2160**  **Controlled Emissions**  

### 502 **Rate (lbs/hr**  **@ rated**  **load) 146**  **502 Rate**  **(lbs/mmBtu) 0.08**  **502 (tpy)**  **237 502 Removed**  **(tpy)** 

### 1923 **Costs** 

### Fixed **O&M $**  **2,067,000 Variable**  **O&M (** **$) 1,01**  **1,000 Total**  **O&M (** **$) 3,078,000**  **Capital Cost**  **89,034,000 Capital**  **Cost (annualized)**  **9,295,150 Total**  **Annual Cost**  **12,373, 150**  **Cost ($/ton**  **502 Removed)**  **6,434 BMcD**  **Estimate** 

### 0.49 **89% 999**  **0.729 2160**  **110 0.08**  **237 1923**  **3,058,000 792,000**  **3,850,000 135,520,000**  **14, 148,289**  **17,998,289 9,359** 


### Fo **l lowing**  **is a**  **di scussion**  **of the**  **diff erences**  **between the**  **cost estima** **tes:**

**•** 

### Capital **Co sts:**  **Bur ns**  **& McDonn** **ell's estima** **te of**  **the inst** **al led**  **dr y FGD**  **co sts**  **was appr**  **oximately 50**  **percent hi**  **gher than**  **the esti**  **mate prepared**  **fo r the EPA.**  **The scope**  **of work**  **was simi**  **lar fo**  **r both**  **estimates including**  **the dry FGD,**  **a new**  **fab ric**  **filter, auxilia** **ry systems**  **and balance**  **of pl**  **ant equipment.**  **Several issues**  **were identified**  **that account**  **fo r**  **much of**  **the dif** 

**f erence.**  **o** 

### The **Region 9**  **estimates inclu** **ded a**  **retrofit fa** **ctor of**  **1 . 0**  **fo r**  **the dry**  **FGD system.**  **•**



### The **site around**  **Uni t 4**  **is ver y**  **congested. Due**  **to the location**  **of the Unit 3**  **cir culating**  **water li**  **nes and**  **other equipmen** **t, a**  **dry FGD**  **and fab** **ric filter**  **could not**  **be loca** **ted immediately**  **ad ja** **cent to**  **Unit 4. There is**  **space behind**  **Unit 3 (where a gas**  **turbine was**  **previously ins** **t all**  **ed )**  **that could**  **poten tially**  **be used.**  **However, the** 

**10**

### May **9, 2013** 

**Page 11** 
**available area**  **is limi** **ted, which**  **wi ll**  **make it**  **diff icult**  **to install**  **a new**  **dry FGD,**  **fa bric**  **fi lter,**  **and ID**  **fa n.**  **It may**  **be nece**  **ssary to install**  **reagent preparation**  **or other**  **equipment at**  **a remote**  **location. With**  **these com** **plic ations,**  **a more**  **appropriate retrofit**  **fa ctor**  **would be**  **1.2 or**  **1 . 3.**  **o** 

### The EPA **cost estimates**  **were based**  **on the**  **IPM report which**  **is in 20**  **10 dol**  **lars. These**  **costs should**  **be esca**  **lated to**  **cur rent**  **dol lars**  **which would**  **add 5**  **to 10**  **percent to**  **the costs.**  **o** 

### The esti **mates did**  **not include**  **any Own er'**  **s costs.**  **Owne r's**  **costs of**  **at least 5**  **percent should**  **be incl**  **uded**
**. •**  

### Fixed **Operating Costs:**  **The fixed operating**  **costs in the**  **esti mate**  **prepared fo** **r Region**  **9 was**  **appr oximately**  **67 percent**  **of the**  **Burns &**  **McDo nnell**  **estimate. Th**  **is was**  **primarily due**  **to using**  **lower main** **tenance mat** **erial and**  **labor costs.**  **The esti**  **mate prepared**  **fo r**  **the EPA**  **has a**  **fixed maintenance**  **and mate** **rial cost**  **of sl**  **ightly over**  **1 percent**  **of capital**  **costs. For**  **a complex**  **system such**  **as a**  **dry FGD**  **with fa** **bric fil** **ter, the**  **costs should**  **be in the**  **range of**  **2- 3**  **percent. •** 

**•** 

### Variable **Opera ting**  **Costs: Burns &**  **McDonne ll's**  **esti mate**  **of the**  **variable operating**  **cos ts**  **was appro** **ximately 30**  **percent lower**  **than the**  **Region 9**  **estimate. We**  **bel ieve**  **much of**  **the dif**  **f erence**  **is due**  **to the**  **auxil iar** **y power**  **consumption which**  **appears to**  **be hi**  **gh in the**  **Region 9**  **estimate. The**  **Region 9**  **esti mate**  **includes appr** **oximately $500**  **,0 00**  **per year**  **in auxi**  **lia ry**  **which corresponds**  **to 1 2**  **00 operating**  **hp. We bel**  **ieve the**  **actual additional**  **usage at** **tributed to the**  **dry FGD**  **would be around**  **900 hp.** 
**Wet FGD**  **A sum**  **mary of**  **the capital**  **and O&M**  **cost esti**  **mates associa**  **ted with**  **ins t** **all ing**  **a wet**  **FGD is**  **provided in**  **Table No**  **6.**

**II**

### May **9, 2013** 

**Page 12** 

**Table No.**  **6 Wet**  **FGD Cost**  **Comparison**

**BART Report**  

### Capacity **Factor 0.37**  **Control Efficiency**  **92% Uncontrolled**  **Rate** 

### 502 **Rate lbs/hr**  **1333 502**  **Rate lbs/mmBtu**  **0.729 502**  **(tpy) 2160**  **Controlled Em**  **issions** 

### 502 **Rate (lbs/hr**  **@ rated**  **load) 110**  **502 Rate**  **(lbs/mmBtu) 0.06**  **502 (tpy)**  **178 502**  **Removed (tpy)**  

### 1982 **Costs** 

### Fixed **O&M $**  **2,700,000 Variable**  **O&M (** **$) 747,000**  **Total O&M**  **($) 3,447,000**  **Capital Cost**  **99,058,000 Capital**  **Cost (annualized)**  **10,341,000 Total**  **Annual Cost**  **13,788,000 Cost**  **($/ton 502**  **Removed) 6,957**  **BMcD Estimate**  

### 0.49 **92% 999**  **0.7 29**  **2160**
**80 0.06**  **178 1982**  **2,812,000 763,000**  **3,575,000 121,990,000**  **12,734,949 16,309,949**  **8,229**


### Bu**ms &**  **McDonn ell's**  **esti mated**  **S02 removal**  **cost is appro** **ximately 18**  **percent hi** **gher than the**  **estima tes**  **prepared fo**  **r Region**  **9. Fol**  **lowing is**  **a dis** **cussion fo** **r the reaso**  **ns.**

**•** 

### Capital **Costs: Bu** **ms &**  **McDonn ell's**  **esti mate**  **of the**  **inst al**  **led wet**  **FGD costs**  **was appro** **ximately 20**  **percent higher**  **than the**  **estima te**  **prepared fo**  **r the EPA.**  **There are**  **several reasons**  **fo r**  **the dif**  **f erence:**  **o** 

### The **estimates prepared**  **fo r**  **the EPA inclu** **ded a**  **retrofit fa** **ctor of**  **1 . 0.**  **The use**  **of a**  **1 . 0**  **retrofit fa** **ctor assumed**  **that the**  **absorber could**  **be loca** **ted immed**  **iately east**  **of the**  **existing fa** **bric filt** **er. However,**  **the Unit**  **3 cir** **culating water**  **li nes**  **are lo** **cated imme** **diately east**  **of the**  **Unit 4**  **fab ric**  **filter. Consequently,**  **the area**  **is not**  **tot ally**  **available fo** **r installation**  **of a**  **FGD syst** **em. The**  **FGD tower**  **could potenti**  **ally be** 

**12 •** **May 9,**  

### 20 **13**

**Page 13** 
**located in**  **this limited**  **area, however,**  **the reagent**  **preparatio n**  **and waste**  **treatment**

**system s**  **would likely**  **have to**  **be located remote**  **. Space**  **would also**  **be needed**  **fo r**  **a new**  **ID fa** **n. Considering**  **these issues, a more**  **appropriate wet**  **FGD retrofit**  **fa ctor**  **fo r**  **Unit 4**  **is** 

### 1.1 **or** 

### 1 .**2. o**  **The existing**  **fa bric**  **filter discharge**  **is to**  **the west.**  **With a wet**  **FGD system,**  **the fa**  **bric filter**  **would need to**  **be reconfigured**  **to discharge to the**  **east. This is**  **another reason**  **the retrofit**  **fa ctor**  **should be**  **increased as**  **discussed above.**  **o The**  **EPA estima**  **te did not**  **include Owner**  **'s costs.**  **Owner 's**  **costs of** 

### 5 **percent should**  **be included.**  **• Fixed**  **Operating Costs:**  **The total fixed**  **opera ting**  **costs were**  **similar fo** **r the two**  **estimat es.**  **The Region**  **9 estimate**  **included more**  **operati ng**  **labor which was**  **off set**  **by a**  **higher estima** 

**te of**  **maintenance materials and**  **labor costs**  **in the Burns**  

### & **McDonnell estimate.**  **• Variable**  **Operati ng**  **Costs: The variable operati** **ng costs**  **were simila**  **r between the**  **estima t** **es. CONCLUSION**  **•**

**Burns** 

### & **McDonnell reviewed**  **the cost**  **estimates prepared**  **fo r**  **the EPA**  **Region 9**  **dated October**  **9,** 

### 20 **12. For**  **all technology**  **cases, the**  **estimates prepared**  **fo r**  **Region 9**  **were lower**  **than Burns**  

### & **McDonnell would expect fo**  **r the Sundt Unit**  **4. Most**  **of the**  **cost variance**  **was due**  **to diff**  **erences between**  **the capital**  **cost estimates.**  **Please advise**  **if you**  **have any**  **questions or**  **comments or if**  **you require**  **additional inf**  **orma tion.**  **Sincerely,** 

# � A- **.� Stephen**  **A. B** 



## j **orklun, P.E.**  **Senior Associa** 

**te Process**  **Engineer Energy**  **Group Burns**  

### & **McDonnell Engineering**  **Company Enclosures** 
**cc: Joey**  **Mashek**

**Block Andrews** 

**13 COPYRIGHT**  **C 2013**  **BURNS &**  **McDONNELL ENGINEERING**  **COMPANY ,**  **INC**

**AIR HE** **ATER** 

## ri **'ftta�**

**U:\MECHDEP n1**  **111 \CADD\M**  **ECH\**

**73483-BJ ORKLUN\EXHIBIT**  **1 . D** **WG 5/8/** **201 3 1**  **:34 PM**  **MATHERTON AIR**  **H E ATER**  **GAS INL**  **ET**

**TEP SUND**  **T UNI**  **T 4 EXH**  **IBIT 1**  **AIR H E** **ATER ARE** **A GAS**  **INL ET**  **DU CT** **COPYRIGHT CI**  **2 01**  **3 BURNS**  **& McDONNELL**  **ENGINEERING COMPANY,**  **INC.**

**POTENTIAL SCR**  **LOCATION ------'**  **UNI T 3**  **CIRCUL ATING**  **WAT ER**  **LINE S**  **---'**

**U : \MECHD**  **EPl\1 111**  **\CADD\MEC H\73483-**  **BJORKLU N\E** **XHIBI T**  **2. DWG**  **5/8/ 20**  **13 1 :**  **41 PM**  **MA THERTON**  **TEP SUND** **T UNI**  **T 4 EX**  **H I BIT**  **2 SI**  **TE PLAN** 

# ATTACHMENT **D**

# A:COM **Envir onm**  **ent Prepared**  **fo r:**  **Tucson Electric Power**  **Tucson. AZ**  **Prepared by:**  **AECOM Chelmsford,**  **MA 60278385**  **.10 0**  **May 20**  **13**



# Visi **bil it** **y I m**  **pr ove**  **ment An**  **aly sis**  **fo r**  **Candida te**  **BART Co**  **ntr ol Op** **t ions**  **: Sun**  **dt U n**  **it 4** 

# AS'COM **Environment Prepared**  **for: Tucson**  **Electric Power**  **Tucson, AZ**  **Prepared by: AECOM**  **Chelmsf**

**ord ,**  **MA 60278385**  **.10 0**  **May 201**  **3**


# Vi **si bil**  **it y**  **I m pr** **ove ment**  **An aly** **sis fo**  **r Candida**  **te BART**  **Co ntr** **ol Op t**  **ions :**  **Su ndt**  **U n it**  **4**

**rt J.**  **Paine and**  **Olga Samani** 

**Reviewed By** **AECOM Environment** 



### Co **ntents**
**Executive Summ**  **ary .........**  **............ ......**  **.... .........**  **... ......................**  **.................................. ES-1**  **1 . 0**  **ln troduction**  **............ ............**  **................. ............**  **............................. ................**  **.................. 1 -**  **1 1 .**  **1 Backgr** 

**ound**
**...... ...........**  **...................... .......**  **................... .............................**  **............... .............**  **1 - 1**  **1 . 2**  **Organization of**  **Repor t**  **........... .**  **.......... .**  **........ ..................................................**  **. . ......................**  **1 - 1**  **2.0 Sund** **t Plant**  **De scription**  **and Nearby**  **Class I Areas**  **..................... ..........**  **..................... 2-1**  **3.0 BART Em**  **ission Cases**  **............ ..........**  **......................... ............................**  **....................... 3-1**  **3.1 BART**  **Option 1:**  **Dry Sorbent**  **In jection**  **(DSI) for**  **S02 Controls**  **and SNCR NOx Controls** 
**. 3-1**  **3.2 BART**  **Option 2:**  **Dry Scrubber**  **for S02**  **and H2S0** **4 Controls**  **and SCR**  **NOx Controls** 
**.... .**  **. .**  **3-1 4.0**  **CALP UFF**  **Mo deling**  **Procedu res**  **................. ..................**  **.................... ...............**  **............ 4-1**  **4.1 CA** **LPUFF Model**  **Formulation for**  **Predicting Visibili** **ty Imp** **air ment**  **............................... .....** **4-1 4.2**  **Ammonia Background**  **Concen trations** 
**............ .**  **. . .............................**  **. ...**  **..... .**  **....................... .**  **. 4-1**  **4.3 CALMET**  **Modeling Pr**  **oced ur**  **es ........................**  **. .**  **................ ..............**  **. . .**  **. ....**  **. .**  **...................... .**  **. .**  **4-4 4.4**  **CALPOST Post Processor**  **and Deciview**  **Calcula tions** 
**............ ......**  **. .**  **. .**  **..... .**  **............... ........**  **... 4-4**  **4.5 CALP**  **UFF Modeling**  **Proced ur**  **es ......................**  **. . ....**  **............. ............**  **. ...**  **..... .**  **....................... ...** **4-5 5.0**  **Vi sibili**  **ty Impr** **ovement Mo** **deling Resu**  **lts ..............**  **.......................... ................**  **........... 6-1**  **5.1 Baseline**  **Emissions Modeling**  **Resu lts**  **fo r BART**  **Scre ening** 
**............ .**  **...... .**  **............ .**  **. .**  **. ....**  **. ...**  **. .**  **5-1 5.2**  **BART Control**  **Option Visibili** **ty Modeling**  **Results**
**.... .................................**  **. ...........**  **. ...**  **.... .**  **... .**  **. 5-2**  **5.3 Visibili** **ty Impr** 

**ovement Effec** 

**tiveness Metrics** 
**. .**  **... ...........................**  **............ .**  **........ ....**  **. .**  **. ........**  **. .**  **5-2 5.3.1**  **Magnitude of**  **Minimum Visibili** **ty Impr** **ovement**
**................ .......**  **. ...............**  **....... . . . .. .**  **5-2 5.3.**  **2 Visibil**  **ity Im**  **provement Cost**  **Effec tiveness** 
**............. ............**  **. . ......**  **. ...........**  **. .**  **. . .**  **... .**  **. . . .**  **. 5-3**  **5.3.3 Visibil**  **ity Modeling**  **Results**
**.... . .**  **..... .**  **.. ..**  **. . .**  **............ .....**  **.............. .**  **. ......**  **. ............**  **.... ..**  **. ..**  **.. .**  **. 5-4**  **6.0 Conclusions**  **...... ....................**  **.......... .............**  **..................................... ........**  **..................... 6-1** 

**Visibility Im**  **provement Analysis**  **for Candidate**  **BART Control Options:**  **Sundt Unit**  **4 May**  **2013 AECOM**  **Environment** 

### ii



### List **of App**  **en dic** **es Appendix**  **A Visibility**  **Modeling Results**  **fo r All Class I**  **Areas**


### List **of Ta**  **ble s**  **Table 3-1**  **: Uni** **t 4 Exhaust**  **Stack Parame** **ters**
**..................... .**  **. .**  **. .**  **... .**  **.. ..**  **. .**  **.............. ....................................**  **3-2 Table**  **3-2: Emissions**  **and Stack**  **Parameters fo** **r Sundt**  **Uni ts**  **1 - 4** 

**. .**  **. .**  **. .................................................**  **3-3 Table**  **4-1 : Backgr** 

**ound Monthly**  **Ammonia Concentrations**  **Used in**  **the Modeling**  **(ppb)**
**...... ............**  **4-4 Table**  **5-1 :**  **98 1h**  **Perce ntile Baseline**  **Case CA** **LPUFF Modeling**  **Resu lts** * **for Visibility**  **Impair ment,** 

**delta-deciv iew** 
**................................................... .**  **............... .................**  **.............................. ...**  **5-1 Table 5-2:**  **Vis ibili** **ty Impr**  **ovement*** **over Baseline**  **Conditions, de**  **lta-deciview**
**............................... ....**  **5-2**



### List **of Figur** **es Figur**  **e 2-1**  **: Photograph**  **of the TEP**  **Sundt Facili** **ty**
**........ ...............**  **........... ...**  **.... ...........**  **....... ........**  **............ 2-1**  **Figur e 2-2:**  **Class I Areas**  **Within 300**  **km of**  **TEP Sund** **t...**
**..... ............**  **..... .......**  **.............. . .**  **....................... 2-2**  **Figur e**  **4-1 :**  **IM PROVE**  **NHx Concentrations**  **from April 201**  **1 to**  **Janu ary**  **201 2**  **............... ........**  **... .........** **4-3 Figur**  **e 4-2:**  **2009 IM**  **PROVE Composition**  **Data for Sagu**  **aro West**  **National Park**  **("SA WE1")**  **and Saguar**  **o East**  **National Par** **k ("SA** **GU 1 "** **)**
**............................. ..**  **. .**  **. .**  **. . ..**  **.. .**  **. .**  **...... .**  **. .**  **. .**  **. .**  **. .**  **. .**  **. .**  **. ...**  **. .**  **. .**  **. .**  **. .**  **. 4-3** 

**Visibility Impr** 

**ovement Analysis**  **for Candidate**  **BART Control**  **Options :**  **Sundt Unit**  **4 May**  **2013 AECOM**  **Environment ES-1** 



### Executive **Summary**

**The Uni** **ted States**  **Environmental Protec**  **tion Agency**  **(EP A)**  **Region 9**  **is anticipa** **ted to**  **foc us**  **in the**  **near future**  **upon a**  **Best Av** **ailable Retr** **ofit Technology**  **(BART) evaluation for**  **the Sundt**  **Uni t**  **4, which**  **can be**  **fired with**  **either coal**  **or natural**  **gas and**  **is located**  **in Tucson,**  **Arizona. Tucson**  **Electric Power**  **Company (TEP)**  **does not bel**  **ieve Sun**  **dt Uni** **t 4 is**  **BART eligible,**  **however, TEP**  **has asked**  **AECOM to**  **review the**  **BART analysis**  **conduc ted**  **fo r**  **EPA 1**  **and to**  **provide a**  **visibili ty**  **assessment for**  **two emission**  **control options**  **for this**  **coal-fired uni** **t:**

**• S02 control**  **using dry**  **sorbent injection**  **(pr ov** **iding 70%**  **control over**  **the baseline**  **emission rat** **e) ,**  **and NOx**  **control using**  **Sele ctive**  **No n-Catalytic**  **Reduction (pr**  **ovid ing**  **30% control**  **over the**  **baseline emission**  **rat e).** 

**• S02**  **control using dr**  **y flue gas**  **desu lfurization**  **("dry scrubbing",**  **pro viding**  **89% contro** **l), and**  **NOx control**  **using Sel**  **ective Catalytic**  **Reduction (prov** **iding 89%**  **contr ol).**  **As a**  **result of this**  **rev iew,**  **AECOM has conduc** **ted new modeling with**  **the followi**  **ng changes**  **from EPA's**  **modeling:**

**• Upda** **ted stack**  **par am**  **eters for**  **Unit 4**  **were modeled**  **based on**  **revised exhaust**  **parame ters**  **provided by**  **TEP.**
**• TEP**  **estimated a**  **rev ised**  **(70%) control eff** **iciency for**  **the dry sorbent**  **injection (DSI)**  **S02 emission**  **controls, slightly**  **lower than**  **what EPA**  **used (75%).**

**• Based**  **upon newly**  **available ammonia**  **measur ement**  **informatio n,**  **AECOM used**  **as inpu** **t to**  **CALP UFF**  **a set**  **of month** **ly-var ying**  **ammonia backgr** 

**ound concentrations**  **that correspond**  **to the**  **actual measu**  **red values**  **during wi**  **nter at**  **a Class**  **I area**  **being modeled**  **in southern**  **Arizo na,**  **which range**  **from 0.5**  **to 1 .**  **0 ppb.**  **EPA had**  **applied a**  **1 . 0**  **ppb ammonia**  **value for**  **all months**  **of the**  **year. A**  **visibili ty**  **impr ovement**  **modeling review**  **was conduc** **ted for all Prevention**  **of Signi** **ficant Deterioration**  **Class I**  **areas within**  **300 km**  **of the**  **plant, using**  **the CALP**  **UFF model**  **version 5.8.**  **This model**  **has a**  **known over-prediction bias**  **for nitr** **ate haze**  **formation that**  **overstates the**  **visibility im**  **provements for**  **the candi**  **date BART**  **options. The**  **modeling also**  **does not**  **account for the**  **haze-ca using**  **effects of**  **ammonia slip**  **from the NOx emission**  **controls that**  **were evaluated. The**  **results of**  **the analysis**  **ind icate**  **even with**  **the model**  **overprediction biases,**  **the only Class**  **I area**  **with 98** **1h percentile**  **daily impa** **cts above**  **the BART**  **contribution to**  **haze scre** **ening level**  **of 0.5**  **de lta**  **deciview is**  **Sagu aro**  **National Park.**  **Even at this**  **park, the**  **candi date**  **controls result**  **in levels**  **of visibili** **ty impr** **ovement that**  **are too**  **low to**  **be detected**  **by the**  **available technology**  **for particul** **ate moni** **tors (well**  **below the**  **measur**

**ement threshold**  **of 0.3**  **del ta-deciview),**  **and they**  **are less**  **than 20%**  **of the**  **percept ible**  **levels that**  **can be**  **visually detected**  **(1 deciview). Furt** **hermore, the**  **cost effec**  **tiveness of**  **both of**  **the control**  **options is**  **hig her**  **than the**  **Federal Land**  **Mana ger**  **-esta blished**  **benchmark of**  **$20 milli** **on/dv. Accord**  **ingly, we**  **conclude that**  **neither of**  **these control**  **options would provide**  **cost-effective visibili** **ty impr** 

**ovement and**  **ther**

**efore it**  **is not**  **rea sonable**  **to re** **quir e**  **additional controls**  **of S02**  **or NOx**  **at Sund** **t Unit**  **4. 1**  **Technical Analysis**  **for Arizona**  **and Hawaii**  **Regional Haze**  **F I**  **Ps :**  **Task 7:**  **Five-Factor BART**  **Analysis for**  **TEP Sundt**  **(Irvington) .**  **EMAQ LOE**  **(EPA Contract**  **EP -** **D**
**- 07-102)** 
**. October**  **9, 2012.**  **Visibility Improvement**  **Analysis for**  **Candidate BART**  **Control Options**  **: Sundt**  **Unit 4**  **May 2**  **0 1**  **3 AECOM**  **Environment 1 -**  **1**



### 1 . **0 I n**  **trod uc** **tion**

**1 . 1**  **Background Even**  **though TEP**  **has sho** **wn that**  **Sundt Uni** **t 4 is**  **not BART**  **eligible, The**  **Uni ted**  **States Environmental**  **Protec tion**  **Agency (EP** **A) Region**  **9 is**  **an tici**  **pated to fo** **cus in the**  **near future**  **upon a**  **BART eva**  **luation for Sundt**  **(f**

**ormerly Ir** 

**vington) Uni** **t 4, which**  **can be fired**  **with either**  **coal or**  **natural gas**  **and is**  **located in**  **Tucson, Arizo**  **na. TEP**  **has asked**  **AECOM to**  **rev iew**  **Sundt Unit**  **4 BART report and**  **modeling prepar**  **ed by**  **the In**  **stitute for**  **the Environment,**  **IFC In** **ternat ional,**  **and Andover Technology**  **Partners for**  **EPA 2** 

**. As**  **a result**  **of this**  **review, AECOM**  **has cond**  **ucted its own**  **modeling that used**  **the EPA-provided**  **modeling as**  **a starting**  **point. However,**  **the up** **dated modeling**  **documen ted**  **in this**  **report uses**  **newly ava**  **ilable information**  **on stack parameters,**  **control eff** **iciencies, and**  **ammonia background**  **input to**  **CALP UFF**  **tha t**  **was not**  **available to**  **EPA when**  **they conduc**  **ted their**  **analysis. AECOM**  **has inco** **rporated these**  **refineme nts**  **in to**  **a visibili** **ty assessment**  **for two**  **emission control**  **options fo** **r Uni** **t 4 that**  **were described**  **in the EPA report:** 

**• Option**  **1: Coal-fired**  **operation with BART**  **controls consisting**  **of dry**  **sorbent in** **jection (DS**  **I) controls**  **for S02,**  **and selective**  **no n-catalytic**  **reduction (SNCR)**  **controls for**  **NOx emissions.** 

**• Option 2:**  **Coal-fired operation with BART controls**  **consisting of**  **spray dr**  **yer absorber**  **("dr**

**y scrubbing")**  **controls for**  **S02 and sulfuric**  **mist (H2S0** **4 )**  **emissions, and**  **sele ctive**  **catalytic reduction**  **(SCR) controls for**  **NOx emissions.**  **This study**  **provides an**  **upda ted**  **comparison of the**  **relative bene** **fits of**  **the two**  **different control**  **options compar**  **ed to**  **baseline conditions**  **with cu**  **rr ent**  **emission control** **s. This**  **visibili ty**  **assessment has**  **been carried**  **out using CALP**  **UF F**  **modeling appr oaches**  **cons istent**  **with those**  **used by**  **the Arizona**  **Department of**  **Envir onmental**  **Quali ty**  **(ADEQ) for**  **their BART**  **visibili ty**  **modeling. Ou**  **r review**  **of the comp** **arative visibili** **ty bene**  **fits addr**  **esses the**  **ben ef** 

**its offe** **red by**  **the two**  **emission control**  **options. 1 .**  **2 Organ**  **ization of**  **Report Section**  **2 of**  **this report**  **provides a**  **description of**  **the Sundt plant**  **and the**  **Prevention of**  **Signi ficant**  **Deterioration (PSD)**  **Class 1**  **areas with**  **in 300 km.**  **Secti on**  **3 discus** **ses the**  **baseline emissions**  **as well**  **as the**  **emissions associated**  **with the**  **two control**  **options that**  **have been**  **modeled. Section**  **4 provides**  **the proced**  **ur**

**es used**  **in the**  **CALP UFF**  **modeling. Section**  **5 presents**  **the results**  **of the**  **modeling and**  **Section 6**  **provides the**  **conclusions of the**  **study.**

**2 Technical**  **Analysis for**  **Ariz ona**  **and Hawaii**  **Regional Haze FIPs: Task**  **7: Five-Factor**  **BART Analysis**  **for TEP Sundt**  **(Irv ington)**  **. EMAQ**  **LOE (EPA**  **Contract EP-D-07**  **-1 02)**  **. October**  **9, 2012.**  **Vlsibllity Impr** **ovement Analysis**  **for Candidate**  **BART Control**  **Options :**  **Sundt Unit**  **4 May**  **20 13** **AECOM Environment** 



### 2.0 **Su ndt**  **Plan t**  **Descri pt**  **ion and**  **Near by**  **Cl ass**  **I Areas**  **2-1**

**Tucson Ele** **ctric Power Company**  **operates the**  **Sundt Generating**  **Station ("Sund** **t"), which is**  **located in**  **Tucson, Arizona,**  **appr oximately**  **2 miles**  **northeast of Tucson**  **In ternatio**  **nal Airport.**  **Figur e**  **2-1 sho** **ws a**  **photograph of**  **the plant.**  **Figur e**  **2-1 : Photograph**  **of the**  **TEP Sundt**  **Facili ty** 

**Ther e**  **are ten**  **Class I**  **areas within**  **300 km**  **(the dis** **tance to**  **which BART**  **visibili ty**  **assessments are**  **typically done) of**  **the source,**  **as shown in**  **Figur e**  **2-2. They are: Mazatza**  **l Wilder** **ness Area,**  **Gila Wilderness**  **Area, Mt.**  **Baldy Wilderness**  **Area, Sie**  **rra Ancha**  **Wi lderness**  **Area, Galiur** **o Wilderness**  **Area, Sup** **erstition Wilderness**  **Area, Pine Mountain Wilderness**  **Area, Chir** **icahua Wilder** **ness Area**  **, Ch**  **iricahua National**  **Monu ment,**  **and Sagu** **aro National**  **Park**
**. Saguar**  **o National**  **Park has two**  **di stric**  **ts - e** **ast and**  **west that are**  **separ ated**  **by the**  **Ci ty**  **of Tucson.**  **Since Sundt**  **is located**  **between the east**  **and west**  **di strict.**  **initial modeling**  **was consid**  **ered for**  **each dis** **trict separ** **ately to**  **determ ine**  **which di** **strict has**  **the higher**  **im pacts.** 

**Visibil ity**  **Impr**

**ovement Analysis**  **for Candidate BART Control**  **Options: Sundt Unit**  **4 May**  **20 13** **AECOM Environment**  **2-2**

**Figur e**  **2-2: Class**  **I Areas**  **Within 300**  **km of**  **TEP Sundt** 

**Mexico Pine**  **Moun**



# Q **M BZatzal**  **Wlldarness V.**  **Wil erness** **'i. Sierra**  **Ancha c.l**  **Wilderness t::.**  **Mount Bal y** 



### Arizona

**legend -tr T** **EP**

**Scala 0** 

### r---:/1 **SUperstition Wilderness**  **Wil erness** 

## fl **Galluro**

## � **Wlldam SI**  **� Saguaro** 

## * **l:J Wast**  **NP Saguaro** 

**East NP** 



### Mexico **Chlrlcahua NM**  **& Chlrlcahua** 

# � **Wilderness**

## Y

**Tucson Electric**  **Power**

**37.5 75**  **Class I**  **Areas Within**  **300 km ofTEP**  **Sundt**

**150 225** 

**Visibil ity**  **Impr**

**ovement Analysis**  **for Candidate**  **BART Control Options**  **: Sundt**  **Unit 4**  

### New **Mexico**

# A: **COM**

**May 20**  **13 AECOM**  **Environment**



### 3.0 **BART Emi** **ssion Cases** 

**This section**  **di scusses**  **the baseline emissions as well**  **as the**  **emissions associa** **ted with**  **the two**  **candi date**  **BART control**  **options tha**  **t have been**  **modeled. The**  **modeled stack**  **parameters fo** **r the**  **baseline coal-firing**  **case and**  **the control**  **options for**  **coal firing are listed**  **in Table**  **3-1**
**.** 

### Unit **4** 

### Baseline **Case 3-1** 

**Table 3-2**  **provides the**  **emissions for**  **S02, NOx,**  **and species of**  **particula te**  **matter (the**  **re quir**  **ed constituents**  **needed for**  **visibili ty**  **impr ovement**  **modeling) for**  **the baseline**  **coal-firing case** 
**. The**  **baseline emissions**  **are the**  **same as**  **those used**  **in EPA's**  **model ing,**  **which are**  **calcu lated**  **from the peak daily**  **emissions for**  **S02 (corres** **ponding to 0.723 lb/MMBtu**  **and 30,950**  **MM Btu**  **heat input)**  **and NOx**  **(corres ponding**  **to 0.434 lb/MMBtu**  **and 30,950**  **MMB tu**  **heat inpu** **t) as**  **der ived**  **from conti**  **nuous emission**  **mon itors,**  **and from**  **the peak daily heat**  **input rate**  **and data**  **from stack**  **tes ting**  **for PM** **10 emissions.**  **The peak**  **daily baseline**  **emissions for**  **S02 and NOx**  **occu rred**  **on 1 /** **1 1 /**  **2008. Cons istent**  **with EPA's**  **model ing,**  **we have**  **included Sundt**  **Uni ts**  **1 - 3**  **as well**  **as Unit**  **4 in**  **all modeled cases. Sin** **ce Uni**  **ts 1 -** **3 are not sub** 

**ject to**  **BART, the**  **emissions for**  **these uni** **ts were**  **kept the**  **same for all cases**  **modeled for**  **Unit 4.**  **Tucson Ele** **ctric spe** **cified slig**  **htly upda** **ted exhaust**  **parameters (relative to**  **the EPA-provided**  **values) for**  **the modeling**  **of Un**  **it 4 based**  **upon stack**  **tests, as**  **noted in**  **the "Sour** **ce" column**  **commen ts**  **in the**  **table. 3.1**  **BAR**

**T Option**  **1: Dry**  **Sorbent In** **jection (DSI)**  **for S02**  **Controls and SNCR**  **NOx Con** **trols Table**  **3-2 provides**  **the visibil**  **ity-a ffecti**  **ng Uni** **t 4 emissions**  **for the**  **case with emission controls**  **fo r**  **S02 and**  **NOx related**  **to coal**  **firing. Co**  **ntrol effic** **iencies for**  **the various**  **control options**  **were provided**  **by TEP.**  **The S02**  **emission rate of 0.22**  **lb/MMBtu corres** **ponds to**  **dry sorbent injection (DSI) and**  **provides 70%**  **control effi** **ciency, while**  **the NOx**  **emission rate**  **of 0**  **. 30 lb/MMBtu**  **corr esponds**  **to appl**  **ication of**  **Se lective**  **No n-Catalytic**  **Reduc tion**  **(SNCR) and**  **provides 30% control**  **effi ciency.**  **All BART**  **emission rates refer**  **to a**  **ro lling**  **30-day aver**  **aging time.**  **3.2 BAR** 

**T Option**  **2: Dry**  **Scrubber for**  **S02 and**  **H2S04 Controls**  **and SCR**  **NOx Controls**  **Table 3-2 provides**  **the visibil** **ity-aff ecting**  **Uni t 4**  **emissions for**  **the case with**  **emission controls**  **for S02**  **and NOx**  **related to**  **coal firing.**  **The S02**  **em ission**  **rate of**  **0.080 lb/MMBtu**  **corres ponds**  **to dry**  **flue gas**  **desu lfu**  **rization "dry**  **scr ubbing"**  **to conserve**  **water resources and**  **maxim ize**  **re moval**  **of sul** **furic acid**  **mist and**  **provides 89%**  **contr ol**  **ef ficiency,**  **while the NOx**  **emission rate of**  **0.050 lb/MMBtu**  **corr esponds**  **to appl**  **ication of**  **Selective Catalytic**  **Red uc**  **tion (SCR) and**  **provides 89%**  **control efficiency.**  **Both of**  **these BART**  **options would**  **likely involve**  **excess ammonia**  **releases to the**  **atmosphere, especially**  **for the**  **SNCR option.**  **The excess**  **ammonia emissions**  **would then**  **combine with gaseous S02**  **and NOx emissions**  **to cause additional**  **haze in**  **both su**  **lfate and**  **ni trate**  **fo rms**  **that would**  **not be**  **present without**  **the NOx**  **control s.**  **Due to**  **the difficul** **ty in**  **simula ting**  **this effect**  **in CAL** **PUFF, it**  **is not**  **included in**  **the modeling.**  **However, it**  **should be**  **noted that with**  **this omission,**  **the CA** **LPUFF modeling**  **results prese** **nted below**  **overstate the**  **visibili ty**  **be nefits**  **of the**  **NOx controls.** 

**Visibility Improvement**  **Analysis for**  **Candidate BART**  **Control Options**  **: Sundt**  **Unit 4**  **May 2013** **AECOM**

**Table 3-1**  **: Unit**  **4 Exhaust Stack Parameters** 



### Un **its**
**UTM- X,**  **Zone 12**  **, NAD83**  **Meters UTM-Y, Zone**  **12 ,**  **NAD83 Meters**  **Stack Height**  **Meter s**  **Base Ele** **vation Meters**  **Effective Diame** **ter Meter** **s Gas**  **Exit Velocity**  **m/s Stack**  **Gas Exit**  **Temper atur** **e deg**  **K** 

### Uni**t 4 Basel**  **ine 508.950**  **3558. 1 4** **8 75.59**  **794.92 3.1**  **3 36.33**  **( 1**  **) 414.2**  **Environment**



### Uni**t 4 Uni** **t 4 Option**  **1 Option**  **2 (SNCR/051)**  **(SCRIDFGD) 508.950**  **508.950 355** **8. 14**  **8 355** **8. 14** **8 75.5**  **9 75.59**  **794.92 794.92**  **3. 13**  **3**
**. 13**  **36 .33**  **(1) 32.48**  **( 2** **) 414**  **.2 352.6**  **(1 )**  **The velocity is based**  **on TEP-pr ovided**  **stack measur** **ements. EPA**  **used a**  **lower exit**  **velocity of**  **28.0 4**  **m/s. (2)**  **The velocity**  **is based**  **on TEP-pr** **ovided stack**  **measur ements,**  **adj us** **ted fo**  **r tem**  **perature and**  **in creased**  **by 5%**  **to account**  **for added**  **moisture. EPA**  **used a**  **lower exit**  **velocity of**  **21 .67**  **m/s. 3-2** 

**Visibil ity**  **Im provement**  **Analysis for Candi**  **date BART**  **Control Options**  **: Sundt**  **Unit 4**  **May 2** **013 AECOM** 

**Table 3-2:**  **Em issions**  **and St**  **ack Parameters for Sundt**  **Units 1 -4** **3**
**Stack Parameters**  **Un it/Case**  **Stack Stack**  **Stack Stack**  **Exit S02** 

**Height Elevation**  **Diameter Temp**  **Velocity m**  **m m**  **K m/s**  **g/s Unit**  **1 39.62**  **794.92 3.21**  **399.82 8.84**  **0.222**
**Unit 2**  **39.62 794.92**  **3.30 399.82**  **8.23 0.547** 
**Unit 3**  **43.89 794.92**  **3.75 392.04**  **8.84 0.328** 

**Unit 4**  **(B as** **eline) 75.59**  **794.92 3.13**  **414.2 36.33**  **117.985**

**Unit 4 S**  **NCR and**  **DSI 75.59**  **794.92 3.13**  **414.2 36.33**  **35.396 (Option**  **1)**

**Unit 4**  **SCR and Dry**  **FGD 75.59**  **794.92 3.13**  **352.6 32.48**  **12.978 (Option**  **2) Environment** 

**Speciated PMlO**  **NOx PMF** 

**fine PMC**  **EC S04**  **g /s**  **g/s g/s**  **g/s g/s**  **12.915 0.**  **000 0.**  **000 0.**  **000 0.**  **000 2** **0. 2** **3 1**  **0. 000**  **0. 000**  **0. 000**  **0. 000**  **18.61 0.**  **000 0.000**  **0. 000**  **0. 000** 

**70.364 0.970**  **1.007 0.037**  **2.561**

**49.255 0.970**  **1.007 0.037 2.561** 

**7. 740 0.768**  **0.797 0.030**  **2.897 SOA**  **g/s 0.**  **000**
**0. 000** 
**0. 000** 

**0.642**

**0.642**

**0.724 3-3** 

**Source**
**Same as**  **the EPA**  **BART Mode**  **lin g**  **2012 111** 

**• Same**  **as the**  **EPA BART**  **Modeling 2012**  **(ll. Same**  **as the**  **EPA BART**  **Modeling 2012**  **111**

**• EPA**  **BART Mo** **delin g**  **2012 except**  **for stack**  **temper ature**  **and vel**  **ocity, which**  **are based**  **on TEP full**  **load data.**  **EPA BART Mode**  **lin g**  **2012 except**  **for stack**  **temper ature**  **and vel**  **ocity, whic** **h are**  **based on**  **TEP fu**  **ll load**  **data. DSI**  **S02 control**  **effieciency is 70%.**  **SNCR NOx**  **control effieciency**  **is 30%.**  **EPA BART**  **Mo deling**  **2012 except**  **vel ocity,**  **whic h**  **is based**  **on TEP full**  **load data**  **adjusted for**  **temper ature**  **and inc** **reased by**  **5% to**  **account for**  **added moisture.**  **DFGD S02**  **control effi**  **ecienc y**  **is 89%.**  **SCR NOx**  **control effi**  **eciency is**  **89%.**

**3 T** **echnical Analysis for**  **Arizona and Hawaii**  **Regional Haze**  **FIPs: Task**  **7: Five-Factor BART**  **Analysis for TEP**  **Sundt (Irvington)**  **. EMAQ**  **LOE (EPA**  **Contract EP-D-0** **7-1 02).**  **October 9,**  **2012.**

**Visibility I m**  **provement Analysis**  **for Candidate**  **BART Control**  **Options: Sundt**  **Unit 4**  **May 20**  **13 AECOM**  **Environment 4-1** 



### 4.0 **CA LPUFF**  **Mod eling Pr** **oced ur** **es**

**In Ju**  **ly 2005,**  **EPA issued**  **BART Guideli**  **nes that**  **provide gu**  **idance to**  **the States**  **in making**  **BART determ**  **inations for**  **large power**  **plants and**  **other BART-** **eligible sour**  **ces 4** 

**. The**  **BART Guideline**  **states that**  **modeling may**  **be necessar**  **y to**  **sup port**  **a decision**  **by the**  **States about**  **which BART-el**  **igibl e**  **sou rces**  **"cause or**  **contrib ute"**  **to visibili** **ty im**  **pairment and are**  **sub je** **ct to**  **BART. 4.1**  **CA LPUFF**  **Model For** **mula tion**  **for Predicti**  **ng Vi** **sib ili** **ty Impairment**  **EPA guidance**  **rec ommends**  **CALPUFF for**  **model ing**  **single sour**  **ce visibili** **ty im**  **pacts at**  **Class** 

### I **areas .**  **The model**  **developer website**  **describes CAL** **PUFF as**  **"**

**... an advanced**  **non-st eady**  **-state mete** **orological and**  **air quali**  **ty mod**  **eling system** 
**... It**  **is maintained**  **by the**  **model developers**  **and distrib**  **uted by**  **TRC. The**  **model has**  **been adopted**  **by the U.S.**  **Envi ronmental**  **Protection Agency**  **(U. S** 
**. EPA)**  **in its**  **Gu idelin**  **e on**  **Ai r**  **Qual ity**  **Models as the**  **pre ferre** **d model fo** **r assessing**  **long range**  **tra nsport**  **of pollutants and their**  **imp acts on**  **Federal Class**  **I areas and**  **on a**  **case-by-case basis**  **fo r**  **certain near**  **field applications**  **involving complex**  **meteo rological**  **cond itio** **ns. Th**  **e mod** 

**eling sys** **tem consi**  **sts of**  **three main**  **components and**  **a set**  **of pr**  **e-processing and**  **post-processing progr**  **ams. The**  **main components**  **of the**  **mod**

**eling sys** **tem are**  **CA LMET**  **(a di**  **agnost ic**  **3-di men** **sion al**  **met**

**eorologi**

**cal model),**  **CALPUFF (an**  **air qua** **lity di** 

**spersion model),**  **and CA**  **LPOST (a**  **post-processing package)**  **". CA** **LPUFF offers**  **three options**  **for dealing**  **with chemical**  **tran sfor** **mations:**

**• A**  **pseu do-first-o**  **rder chemical**  **reaction mechanism**  **for the**  **conversion of**  **S02 to**  **S0 4**  **and NOx**  **to N0** **3 .**  **This mechanism is**  **based on**  **the chemical**  **tran sformation**  **scheme used**  **in the**  

### MESOPUFF-11**5 model**  **and incorpor** **ates the**  **most sig**  **ni ficant**  **dependencies of**  **spatially and**  **temporally var** **ying environmental**  **conditions of the transfor** **mation rates.** 

**• The**  

### RIVADIA **RM3 scheme** **6 ,**  **which treats**  **NO and**  **N02 conversion**  **process in addi** **tion to**  **the N02 to**  **N0 3**  **and S02**  **to S0** **4 conver**  **sions, with**  **equili brium**  **between gaseous**  **HN03 and**  **ammonium ni** **trate aer**  **osol.**

**• Us** **er-specified 24-hour**  **cycles of**  **transformation rates.**  **The In** **teragency Workgroup**  **on Air**  **Quali ty**  **Modeling (I** **WAQ M)**  **rec ommends**  **using the**  **MES OPUF**  **F 11**  **system with**  **CA LPUFF.**  **This chemis** **try option**  **is also**  **the model**  **def ault**  **rec ommended**  **by EPA.**  **4.2 Am**  **mo nia**  **Background Conce**  **ntrations**
**In the**  **CA LPUFF**  **model, the**  **oxidation of**  **NOx to**  **ni tric acid**  **(HN0 3** **) depends**  **on the**  **NOx concentrat** **ion, ambient**  **ozone concentrat** **ion, and**  **atmospheric stability.**  **Some of**  **the nitric**  **acid is**  **then combine** **d with available**  **ammonia in**  **the atmospher e**  **to fo** **rm ammonium**  **ni trate.**  **The amount**  **of ambient**  **ammonia concentrations**  **is a**  **critical input**  **to the**  **CALPUFF model**  **fo r**  **nitrate forma** **tion, especially with**  **the use**  **of**

**• US**  **EPA, 2005** 
**. BART**  **guidelines, Federal**  **Register update** **: June**  **24, 2005.**  **5 Scire**  **et. al.,**  **1 9 84.**  **User's Guide**  **to the**  **MESOPUFF II**  **Model and**  **Related Processor**  **Programs, 1 9** **84 .**  **EPA-600 S8-84-0**  **13. May**  **1 9 84.**  **• Morris**  **et. al**  **.,19 88.**  **Rocky Moun** **tain Acid**  **Deposition Model**  **Assessment: Acid**  **Rain Mountain Mesoscale Model (ARM3),**  **EPA 1 9** **88. Visibility**  **Imp rovement**  **Analysis for**  **Candidate BART**  **Control Opti**  **o ns**  **: Sundt**  **Unit 4**  **May 2** **0 1**  **3 AECOM**  **Environment**

**the MES** **OPUFF II chemis** **try. It is**  **imp ortant**  **to note**  **that that**  **only particula** **te ni** **trate will**  **im pact**  **visibil ity,**  **ni tric**  **acid would not.**  **4 -2** 

**Morris et**  **al. 7**  **reported that**  **the EPA-appr** **oved version**  **of CALPUFF**  **with the**  **MESOPUFF II chemis** **try (V** **ersion 5.8** **) was developed**  **from field data**  **lim ited to**  **am bient**  **temper atures**  **no lower than**  **50°F. Ther** **efore, the**  **use of**  **CAL PUFF**  **for much**  **lower tem**  **peratures for**  **the critical**  **wi nter**  **season represe** **nts an**  **exten sion**  **of the model**  **to un** **tested conditions.**  **Morris et**  **al. fo** **und that the**  **lim itations**  **of the am**  **bient temper**  **atur es**  **in the**  **field data used**  **in development**  **of the**  **model could**  **result in**  **overes timating**  **su lfate**  **and ni** **trate fo** **rmation in**  **colder conditions.**  **These in** **vestigators found**  **that CAL**  **PUFF (version**  **5.8) tended**  **to over** 

**-predict ni** **trate concentrations**  **du ring**  **winter by**  **a factor**  **of about**  **3 with**  **high ammonia**  **background concen** **tra tions.**  **Recently, the**  **IM PROVE**  **mon itoring**  **network began**  **to inc** **orporate routine**  **measur ements**  **of gaseous**  **ammonia at**  **specific sites.**  **A rece** **ntly issued**  **te chnical**  **paper 8**  **on this**  **sub ject**  **sho wed**  **monthly ammonia**  **measur**

**ements at**  **these sites,**  **including one**  **in southern**  **Arizona (Ch**  **iricahua) that**  **was modeled**  **for this**  **study. A**  **review of the**  **measur ements**  **taken to**  **date at**  **these sites**  **(see Figur** **e 4- 1)**  **ind icates**  **that ammonia**  **concen trations**  **less than**  **below 1**  **ppb (e** **.g., 0.5**  **ppb) are**  **present at**  **this site**  **in winter.**  **Note that**  **EPA used**  **a constant**  **value ammonia**  **backgr ound**  **level of**  **1 ppb**  **for all**  **12 months,**  **but without**  **the ben efit**  **of the**  **recent IM**  **PROVE measurements.**  **In an independent**  **analysis, the**  **Colorado Department**  **of Public**  **Health and**  **Environment (CDPHE)**  **performed a sensitivity**  **modeling analysis to explore**  **the effect**  **of the ammonia concentration**  **input to**  **CAL PUFF**  **on the**  **predicted visibili** **ty impa** **cts fo** **r a sou**  **rce with**  **high NOx**  **emissions relative**  **to S02 emissions.**  **9 It**  **is notew** **orthy that**  **the largest**  **sens itivity**  **occurs for**  **ammonia input**  **values betwee**  **n 1 and**  **0.1 ppb.**  **In that**  **range, the**  **di ffe** **rence in**  **the peak**  **visibility im**  **pacts predicted**  **by CA** **LPUFF is**  **slightly more**  **than a**  **facto r**  **of 3 between**  **ammonia concen** **tration input**  **values of**  **1 and 0.1**  **ppb. This**  **sensi tivity**  **analysis shows**  **that the**  **choice of**  **background ammonia is**  **very im** **portant in**  **terms of**  **the magni** **tude of**  **visibili ty**  **im pacts**  **predic ted**  **by CALP**  **UFF, and**  **tha t**  **the assump** **tion of**  **1 ppb**  **for winter**  **likely introduces**  **another level**  **of over-predictive**  **conser vatism**  **in the**  **modeling results**  **for NOx**  **effects upon**  **haze. The**  **visibili ty**  **composition plots**  **depi cted**  **in Figur**  **e 4-2 are**  **from two**  **IM PR** **OVE moni** **tors located in**  **Sagu aro**  **West National**  **Park and**  **Saguar o**  **East National**  **Monum ent**  **sho w**  **that the majority**  **of ni**  **trates (shown**  **by red**  **portions of**  **the composition**  **columns) form**  **during cold**  **tempe rature**  **(in the**  **modeled predictions**  **and in**  **the real**  **world) and, ther**  **efore, the**  **model is**  **not sensitive**  **to the se** **lected ammonia**  **values in**  **summer, but**  **would be**  **highl y**  **sensi tive**  **to values**  **in winter**  **months. Based**  **upon this**  **newly available**  **ammonia measurement**  **in formation**  **(which con**  **servatively includes**  **both gaseous**  **and particula** **te form**  **concentration contr** **ibutions), AECOM**  **has developed**  **a set**  **of monthly** **-var**

**ying ammonia background**  **concen tra** **tions (see**  **Table 4-**  **1) that**  **corres pond**  **to the**  **actual measured**  **values noted**  **above. Cons**  **istent with**  **the EPA**  **values, an**  **ammonia background of**  **1 ppb**  **is used for**  **many of**  **the non-winter**  **months.**
**7 Manis,**  **R., Steven**  **Lau and Bonyoung**  **Koo, 2005. Evaluation**  **of the CALPUFF**  **Chemistry Algorithms.**  **Presented at**  **A&WMA 98** **11 Annual**  **Conference and**  **Exhibition, June 21**  **-25, 2005**  **Minneapolis, Minnesota.**  **8 Chen,**  **X., D.**  **Day, B.**  **Schichtel, W.**  **Maim, J. Mojica, C.**  **McDade, E.**  **Hardison, S.**  **Kreidenwei s,**  **and J.**  **Collett, 2012.**  **A Pilot**  **Monitoring Study**  **of Atm**  **ospheric NHx**  **at Selected**  **IM PROVE**  **Sites. Extended**  **Abstr act**  **# 19.**  **Presented at**  **the 201**  **2 Aerosol**  **and Atm** **ospheric Optics:**  **Visibilit y &**  **Air Pollution Specialty**  **Conference, held**  **September 25-28**  **" .**  **2012 in**  **White fish. MT.**  **Air &**  **Waste Management**  **Association, Pittsburgh,**  **PA. 9**  **Supplemental BART**  **Analysis: CALP**  **UFF Protocol**  **for Class**  **I Federal**  **Area Visibility**  **Improvement Modeling Analysis (DRAFT)**  **, revised**  **June 25,**  **2010, available**  **at http://** **www .colorado.gov**  **/airqual ity/d**  **ocumen ts/Draft**  **ColoradoSupp lementaiBART**  **AnalysisCALPU FFProtocoi-25June201**  **O.pd f.**  **Visibili ty**  **Impr ovement**  **Analysis for**  **Candi date BART**  **Control Options**  **: Sundt**  **Unit 4**  **May 20**  **13 AECOM**  **Environment**

**Figure 4-1 :**  **IMPR OVE**  **NHx Conce**  **ntrati ons**  **fro m**  **April 201**  **1 to**  **January 201**  **2**

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**Saguar o**  **East National**  **Park ("SAGU1 ")** 



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**Table 4-1**  **: Background**  **Monthly Ammonia**  **Conce ntr** **ations Used**  **in the**  **Modeling (ppb)**  **Jan Feb**  **Mar Apr**  **May Ju**  **n Jul**  **Aug Sep**  **Oct Nov**  **0.5 0.5**  **0.6 0.7**  **1 . 0**  **1 . 0**  **1 . 0**  **1 . 0**  **1 . 0**  **1 . 0**  **1 . 0** 
**4.3 CALMET**  **Model ing**  **Proc edur**  **es 44** 

**Dec 0.8** 

**The Western**  **Regional Air**  **Partnership (WRAP)**  **developed six**  **4-kilom eter**  **(km) CALMET**  **meteor ological**  **databases for**  **thr ee years**  **(2001 -2003).**  **The CALMET**  **modeling domains**  **were strateg**  **ically desig ned**  **to cover**  **all potential**  **BART eligible**  **sources with**  **in WRAP**  **states and**  **all Prevention**  **of Sign**  **ific ant**  **Deterioration (PSD)**  **Class I**  **areas within**  **300 km**  **of those sour**  **ces. The**  **extents of the**  **six domains are**  **sho wn**  **in Figur**  **e 3-a through**  **Figur e**  **3-1 f**  **of the WRAP common**  **BART modeling**  **protoco l,**  **av ailable**  **at http://p**  **ah.c ert.**  **ucr.ed u/ag** 

**m/308/bar**

**tJWRAP RMC**  **BART Protocol**  **Auq1 5**  **2006**

**. pdf** 

**. The**  **WRAP CALMET**  **meteor**

**ological inp**  **uts, tech**  **nical options,**  **and proce** **ssing steps**  **are described**  **in Sections**  **2 and**  **3 of**  **the WRAP**  **protoco l.**  **U.S. Geological**  **Sur vey**  **(US GS)**  **3 arc-second**  **Dig ital**  **Ele vation**  **Model (OEM)**  **files were**  **used by**  **WRAP to**  **gener**

**ate the**  **terr**

**ain data**  **at 4-km**  **reso lution**  **for input**  **to the**  **six CALMET**  **runs. Likewise,**  **the Composite**  **Theme Grid**  **format (CTG)**  **files using**  **Level I**  **USG S**  **land use**  **categories were**  **used by**  **WRAP to**  **gener ate**  **the land**  **use data**  **at 4-km**  **resolution for**  **input to**  **the six CALMET runs. See**  **Sections 3.**  **1 . 1**  **.3 -3.**  **1.1. 4**  **of the**  **WRAP BART**  **modeling pr**  **otocol fo** **r det ails**  **on the data**  **pr oc** **es sing.**  **Thr ee**  **years of**  **36-km MMS**  **da ta**  **(2001 -2003)**  **were used**  **by WRAP**  **to gener** **ate the**  **4-km sub**  **reg ional**  **meteoro logical**  **da tasets.**  **Section 2**  **of the WRAP protocol**  **discusses MMS data**  **extrac tion.**  **The BART**  **CALPUFF modeling for**  **Sun dt**  **was done**  **using the**  **Arizona 4-km CALMET database with**  **appl ication-specific**  **modifications and**  **adjustments later**  **requested by**  **EPA Region**  **9, such**  **as:**

**• AECOM**  **used a**  **smaller R1**  **value of**  **18 km**  **and R1**  **MAX value**  **of 30**  **km in**  **comparison to**  **the R1**  **of 1 0**  **0 km**  **and R1**  **MAX of**  **50 km**  **used by WRAP.**  **Shrinking these weighting**  **factors avoids**  **abrupt transition**  **of su**  **rface winds.**  **The adju**  **sted R1**  **and R1**  **MAX values**  **blend the**  **sur face**  **observations into the**  **MMS observations**  **much bette** **r, crea** **ting a more**  **uni form**  **wind field**  **throughout the**  **domain.**

**• When**  **reru nning**  **CA LMET,**  **AECOM used**  **the latest**  **EP A-appr** **oved version of**  **CALMET (V** **ersion 5.8,**  **Level 070623) in** **stead of Version**  **6.21 1**  **tha t**  **was used**  **by WRAP.**  **4.4 CALPOST**  **Post Processor and**  **Decivie w**  **Calcula tions**  **CALPUFF uses**  **predictions of**  **various particula** **te species to compute**  **the visibili** **ty extinction**  **using the**  **In teragency**  **Mon itori**  **ng of**  **Protected Visual**  **Envir onments**  **(IMPR OVE)**  **equa tion (both**  **original 1**  **0 and** 

**1° Federal**  **Land Managers,**  **2001 .**  **Federal Land**  **Managers' Air**  **Quality Related**  **Values Workgroup**  **(FLAG) Phase**  **I Rep** **ort. http**  **: /**  **fv.N.N/2. .nature.n** 

**ps .**  **gov l**  **ardlfl agfr** 

**eel index** **.htm**
**. Visibility**  **Impr**

**ovement Analysis**  **for Candidate**  **BART Control**  **Options :**  **Sundt Unit 4**  **May 2** **0 1**  **3 AECOM**  **Environment 4-5** 

**"n ew"**  **1 1**  **versions as**  **docu mented**  **in the**  **Federal Land**  **Manag ers'**  **Air Qua** **lity Related**  **Values Workgr**  **oup (FL**  **AG) reports.**  **The up date**  **to the**  **IM PR** **OVE equation,**  **adop ted**  **in the**  **FLAG 20**  **10 version,**  **is based**  **upon a**  **re-eva lua** **tion of**  **the comparison**  **between particula** **te species**  **concentr ations,**  **relative humid**  **ity, and**  **dir ectly-observed**  **light scatt** **ering. Dur**  **ing most**  **of the**  **BART analysis**  **per iod**  **between 2005**  **and 201**  **0, however,**  **EPA has**  **relied upon**  **the original**  **IM PROVE**  **equation. The**  **model user**  **provides specific**  **inpu ts**  **for the**  **CAL POST**  **post-processor as**  **noted in**  **FLAG reports**  **reg arding**  **the use**  **of the**  **original and**  **new IMPR** **OVE equations.**  **In addition**  **to the**  **choice between**  **these equations,**  **the CALPOST**  **user needs**  **to define the**  **natural backgr** **ound particula** **te concentr**  **a tions.**  **The BART Rule**  **specifies tha** **t the**  **visibili ty**  **impr ovement**  **for various**  **emission cases**  **needs to**  **be refere**  **nced to**  **"clean" natu**  **ral conditions, which**  **can be defined**  **in two**  **alternate ways:**  **the annual**  **average natural**  **conditions (referred**  **to as option**  **"a") and**  **the conditions**  **associa ted**  **with the**  **20% best**  **days (referred**  **to as**  **option "b").**  **EPA guidance**  **provides each**  **state the**  **option to choose**  **between the**  **two definitions**  **of natural**  **conditions. As**  **EPA noted**  **in its**  **July 20,**  **201 2**  **proposed rule,**  **Arizona selected**  **the annual**  **average natural**  **backgr ound**  **and the**  **original IM**  **PROVE equation**  **(also termed**  **"Me thod**  **6") for**  **use in**  **the State**  **'s BART**  **anal yses.**  **These selections**  **corresp ond**  **to "M** **ethod 6a"**  **in the**  **terminology adopted**  **in EPA's**  **proposed rule.**  **The modeling**  **resu lts**  **presented in**  **this document**  **were based**  **on Method**  **6a, consistent**  **with the**  **procedures used**  **by the**  **state of**  **Arizo na.**  **4.5 CAL** **PUFF Model**  **ing Pr** **oced ur** **es AECOM**  **cond ucted**  **CALPUFF modeling**  **of the**  **basel ine**  **and emission**  **control cases**  **for Sundt**  **using the**  **EP A-appr** 

**oved version**  **of CA** **LPUFF (vers**  **ion 5.8).**  **1 2**  **In recent**  **years, TRC,**  **the company**  **that maintains**  **the CALPUFF**  **model, has**  **released a new version (6.42)**  **of CALPUFF**  **to fix**  **certain cod**  **ing "bugs"**  **in EPA-appr** 

**oved version**  **5.8 and**  **to si** 



## � **ni ficantly**  **impr**

**ove the**  **chemis try**  **module. CALP**  **UFF has**  **been ev** **alua ted**  **by several**  **investiga tors**  **1 ·1**  **4 '** **1 5**  **and the**  **results ind**  **icated tha** **t the EPA-appr** **oved vers**  **ion using**  **the MESOPUFF**  **II chemis** **try sign**  **ificantly over-predicts**  **ni trate**  **form ation**  **in wintertime**  **conditions. However,**  **EPA has**  **been sl** **ow to**  **adopt this**  **version of CALPUFF**  **or even fix**  **the bugs in**  **vers ion**  **5.8, so**  **we are cu**  **rr ently**  **left with that**  **version for BART**  **modeling. As**  **a res**  **ult, the**  **predic ted**  **visibili ty**  **impr ovements**  **fo r**  **NOx controls**  **are overstated**  **as a**  **result of**  **the known**  **bias es**  **of the**  **chemis try**  **algor ithm used**  **in CALPUFF**  **v. 5**
**. 8** 
**.**

**11 Federal**  **Land Managers, 201**  **0. Federal**  **Land Managers'**  **Air Quality**  **Related Va** **lues Work**  **Group (FLAG)**  **Phase I**  **Report Revised**  **(2 010).**  **Natural Reso**  **urce Report**  **NPS /** **NRPC /** **NRR**
**- 201**  **0 /** **232 .**  **http //na** **tur**

**e. n**  **p s.**  **gov ai**  **r/pu b** **s /pdf**  **/fla /FLA** **G 201**  **0. pd** **f**
**. '2**  **AECOM used the EPA-approv** **ed vers**  **ion of**  **CALPUFF (Vers**  **ion 5.8,**  **Level 070623)**  **that has**  **been posted**  **at h** **ttp: //w.vw** 
**. sr** **c .c** **o m/ca**  **lpuff/do wnload/down**  **load.htm #** **EPA VER**  **S ION** 
**. 13**  **Scire, J.S.,**  **Z-X Wu,**  **D.G. Strimaitis and**  **G.E. Moore,**  **20 01:**  **The Southwest**  **Wy oming**  **Regional CALP**  **UFF Air**  **Qua lity**  **Modeling Study**  **- Volume**  **I. Prepared**  **for the**  **Wyo ming**  **Dept of**  **Environmental Qual**  **ity .**  **1• Karamchan** **dani, P.,**  **S. Chen,**  **R. Bronson,**  **and D.**  **Blewitt, 2009.**  **Deve lopment**  **of an Improved**  **Chemistry Vers**  **ion of**  **CAL PUFF**  **and Evaluation**  **Using the**  **1 9 95**  **S#INYT AF Data**  **Base. Presented**  **at the Air**  **& Waste Management**  **Associati on**  **Specialty Conference**  **on Guideline**  **on Air**  **Qual ity**  **Models: Next**  **Generation of Models.**  **October 28-30,**  **2009, Raleigh, NC.**  **15 Monis,**  **R., Steven**  **Lau and**  **Bonyoung Koo.**  **2005. Evaluation**  **of the**  **CALPUFF Chemistry**  **Algorithms .**  **Presented at**  **A&WMA 98** **11 Annual**  **Conference and**  **Exhibition, June**  **21- 25,**  **2005 Minneapolis,**  **Minnesota. Visibility**  **Impr ovement**  **Analysis for**  **Candida te**  **BART Control**  **Options :**  **Sundt Unit**  **4 May**  **20 13** **AECOM Environment**  **4-6**

**The BART**  **Rule ind**  **icates that**  **a sour** **ce will**  **screen out of**  **a BART**  **determ ination**  **if the**  **baseline emissions**  **show visibility**  **impair ment**  **relative to**  **natural conditions below 0.5 de** **lta-deciview (the**  **"contribution" level),**  **if the**  **state sel** **ects this**  **level for**  **the scre** **ening thr**  **es hold.**  **Arizona has**  **selected a**  **0.5 de** **lta-deciview threshold**  **for this**  **pur pose.**  **The CALPUFF comp**  **utati onal**  **modeling domain was**  **defined based**  **on a**  **50-km buffer**  **around each**  **of the ten**  **Class I**  **area, shown**  **in Figur** **e 2-2.**  **A 50-km**  **buf fe**  **r around**  **each Class**  **I area**  **accounts for**  **puff re-c** **irculations. Using**  **a smaller**  **computational grid**  **within the**  **WRAP CALMET**  **domain minimi** **zes compu** **tation time and output**  **file size.**  **The receptors**  **used for**  **each of**  **the Class**  **I areas**  **are based**  **on the National**  **Park Service**  **database of**  **Class I receptors. WRAP**  **has developed**  **hourly ozone**  **measur ement**  **files for**  **three years**  **(2001 -2003),**  **ava ilable**  **at http**  **: //p**  **ah.c ert** 

**. ucr.ed**  **u/a**

**q m/308/ba** **rt /calpuff** 

**/ozo ne**  **daU**
**. Data**  **collection and**  **proces sing**  **are described**  **in Section**  **3.1 .2.7**  **of the**  **WRAP pr**  **otoco l.**  **These ozone**  **data files**  **were used**  **as input**  **to CA** **LPUFF. AECOM**  **ran each**  **emission scenario**  **with the**  **month ly-vari** **able ammonia**  **background concen** **tration ,**  **as sho** **wn in Table 4-1** 

**.**

**Visibility Impr** 

**ovement Analysis**  **for Candida** **te BART**  **Control Options**  **: Sundt**  **Unit 4 May**  **20 13** **AECOM Environment** 



### 5.0 **Vi sibili** **ty Impr** **ov ement**  **Mod eling**  **Res u**  **lts**

**5.1 Ba** **selin e**  **Em issions**  **Mod elin**  **g Resu**  **lts for BART**  **Scr e**  **ening 5**  **-1**

**The first**  **step in**  **the BART**  **rev iew**  **was the**  **modeling of**  **baseline emissions**  **to det** **ermine whether**  **any Class**  **I areas**  **are associated**  **with visibili** **ty impair** **ment relative**  **to natural**  **conditions exce** **eding 0.5**  **delta -decivie** 

**w (del** **ta-dv)**

**. Results**  **pr esented**  **in Table**  **5-1 are the**  **3-year average**  **of the**  **98 th**  **percentile delta-dv**  **pr**

**edicted im**  **pacts for each Class**  **I area.**  **The BART**  **guidelines indic** **ate that**  **sour ces**  **are exempt**  **from BART**  **determ inations**  **if they**  **do not**  **cause or**  **contribute to**  **visibili ty**  **imp air** **ment at**  **Class I**  **areas. Except**  **for Saguaro National**  **Park, this**  **is the case**  **fo r**  **the baseline emissions from**  **the Sun**  **dt Gen**  **era ting**  **Station; the**  **98 th**  **percentile day's**  **impa cts**  **are less**  **than 0.5**  **de lta-dv.**  **Ther efor** **e, the**  **focus of**  **the visibili** **ty im**  **provement analysis**  **is on**  **Sagua ro**  **National Park.**  **Due to**  **the fact**  **that the**  **haze im**  **pacts are**  **higher for**  **the eastern**  **portion of**  **this Class**  **I area,**  **the BART**  **determ ination**  **modeling fo** **cused upon**  **that area.**  **For supple** **mental informatio**  **n, the**  **visibi lity**  **impr ov** **ement for**  **the candida** **te BART**  **control options that we**  **modeled at**  **other parks**  **for which**  **Sundt does**  **not contribute to**  **visibi lity**  **impairment is**  **provided in**  **Appendix A.**  **Table 5-1 :**  **981h Percentile Bas** **eline Case**  **CALPUFF Modeling**  **Results*** **for Visibili** **ty Im**  **pairment, delta** 

**deciview**


### Class **I Area Basel**  **ine Ma** **zatzal W**  **0.0 4**  **Gila W**  **0.08 Mt.**  **Baldy 0.05**  **Si erra**  **Ancha 0.06**  **Galiur o W**  **0.45 Su**  **perstition W**  **0. 12**  **Pine Mountain**  **W 0.0**  **3 Chir** **icahua W**  **0.1 8**  **Chir icahua**  **NM 0.1**  **9 Sagu**  **aro East NP**  **1 . 37**  **Saguar o West**  **NP 1 .**  **01** ***** **96., percentile**  **day's visibility**  **impairment over**  **3 years**  **modeled, relative**  **to natural**  **conditions**

**Visibility Improvement**  **Analysis for**  **Candidate BART**  **Control Options**  **: Sundt**  **Unit 4 May**  **2013 AECOM**  **Environment 5-2** 

**5.2 BART**  **Control Option**  **Vis ibil**  **ity Mode**  **ling Resu**  **lts The**  **results of**  **the BART**  **control options**  **visibi lity**  **modeling for**  **Saguaro National**  **Park (eastern**  **portion) are**  **present ed**  **in Table 5-2.**  **This table sho** **ws the**  **im prov** **ements in**  **the visibili** **ty impair** **ment for**  **the two**  **control options**  **relative to**  **the baseline**  **case for**  **Sagu aro**  **National Park.**  **It is**  **notewo rthy**  **that as**  **the plume**  **tem perature**  **is lowered**  **by the**  **S02 control** **s, especially**  **associated with**  **dry FGD,**  **the terra** **in imp** **acts at**  **Saguaro National**  **Park result**  **in visibi**  **lity de**  **gr adation**  **for Option**  **2 relative**  **to Option**  **1. The**  **next su**  **b-section disc**  **usses the**  **effect iveness**  **of these**  **control options.**  **Table 5-2:**  **Visibili ty**  **Impr ovement** * **over Baseline**  **Condi tions,**  **delta-decivie w**  

### Visibil **ity Vis**  **ibili ty**  **Impr ovement**  **for Im**  **provement for**  **Class I**  **Area Option**  **1: Option**  **2: SNCRJDSI**  **SCRIDFGD on**  **Uni t 4**  **on Unit**  **4 Saguar** **o East**  **NP 0.**  **1 6 4**  **0. 1 2**  **8 •**  **98th percentile**  **day's visibility**  **im pairment**  **over 3**  **years modeled**  **5.3 Vis**  **ibil ity**  **Impr ovement**  **Effe cti** **veness Metrics**  **Although the**  **BART Rule**  **implies, but**  **does not specifically**  **provide, metrics**  **fo r**  **deter mining**  **whether BART**  **control options**  **have sufficient**  **visibility impr**  **ovement for**  **a reaso** **nable cost**  **to be re** **commended, actual**  **policies developed**  **in practice**  **over the**  **years since the**  **BART Rule was issued**  **can be**  **drawn upon**  **to provide**  **guid ance**  **in this**  **respect. There**  **are two**  **types of**  **metrics available:** 

**• The magnitude**  **of the**  **visibili ty**  **impr ovement,**  **expressed in**  **deci views**  **averaged over**  **the years**  **modeled, should**  **be hi** **gher than**  **a minimal**  **value that**  **is related**  **to the**  **abili ty**  **for measur**  **ement systems**  **to actu ally**  **detect a**  **differ ence**  **between measur**  **ements of**  **visibi lity**  **that could be**  **identical**

**. There**  **are also**  **polic y-related**  **stat ements**  **of minimal**  **visibili ty**  **impr ovement**  **magnitudes.**

**• The**  **cost effec** **tiveness of**  **the visibili** **ty im**  **provem ent,**  **expressed in**  **dol lars**  **per deciview, should**  **be higher**  **than a**  **benchmark value est** **ablished by**  **the Federal**  **Land Mana** **gers. These metrics**  **are further**  **discussed below.**  **5.3.1 Magnitude**  **of Minimu**  **m Vi** **sibili ty**  **Im provem**  **ent**

**• The**  **northeastern states Regional**  **Planning Or**  **gan izati** **on, MAN**  **E-VU (as**  **documen ted**  **by many**  **stat es;**  **see www**  **mass .go** **v/de /air**  **pr iorit** **ies/hazebart doc**  **, has**  **determ ined**  **that a**  **"degree of**  **visibi lity**  **impr ovement"**  **tha t**  **is very**  **small (<** **0.1 de** **lta-deciview) is**  **such that**  **no reas** **onable weighting could**  **jus tify**  **additional controls**  **under BART.** 

**• EPA's**  **Regional Haze**  **Rule mentions**  **16 that**  **"no degr** **adation" to**  **visib ili** **ty would**  **be "defined**  **as less**  **than a**  **0.1 deciview**  **increase."**

**16 64**  **FR 35730.**  **Visibility Im**  **provement Analysis**  **for Candidate**  **BART Control**  **Options :**  **Sundt Unit**  **4 May**  **20 13** **AECOM Environment**  **5-3**

**• For**  **the Reid**  **Gardner Gen**  **era ting**  **Station BART**  **visibi lity**  **analysis 17**  **, EP**  **A selected**  **SNCR over**  **SCR controls**  **because the**  **incr emental**  **visibili ty**  **impr ovement**  **between the**  **two options**  **was only**  **0. 1**  **delta-dv; too**  **small to**  **jus tify**  **the cost**  **of installing**  **SCR.**

**• The**  **uncertai nty**  **in measur** **ements of**  **identical visibi**  **lity conditions**  **reported by**  **Tombach (2002)** **16 is**  **estima ted**  **to be**  **about 0.3**  **delta-deciview.**

**• In**  **its consider** **ation of**  **a proposed**  **secondar y**  **PM2**

**. 5**  **NAAQS involving**  **visibili ty,**  **EPA docum** **ented 1**  **9 measurement**  **uncertainties in**  **the visibil**  **ity index**  **(VI) ind**  **icate a t**  

## �**pical uncertai**  **nty in**  **the VI**  **of 2%.**  **With curr** **ent (baseline)**  **measur ements**  **of visibili** **t**

## l **for the 20%**  **worst da** **ys at**  **Sagu aro**  **National Park**  **at about**  **1 5 .5**  **deciviews, this**  **uncertainty is**  **on the**  **order of**  **0.3 delta-deciview.**  **Based upon this**  **in fo** **rmati on,**  **it is reasonable**  **to conclude**  **that a**  **pred icted**  **visibility imp**  **r ovement**  **on the order**  **of 0.1**  **de lta-deciview**  **or less**  **can clearly**  **be dism**  **issed as insig**  **nificant. Furt** **hermor e,**  **it is**  **evident that**  **a visibili** **ty impr** 

**ovement less**  **than 0.3**  **del ta-deciview**  **canno t**  **be detected**  **with cu**  **rrent measurement**  **syst ems.**  **That value**  **is also**  **below the**  **0.5 de** **lta-deciview level**  **of "** **cont r** **ibut i** **on "**  **to haze**  **in the BART rule,**  **and is**  **only 30%**  **of the**  **1 del** **ta-deciview value**  **that the**  **BART Rule**  **mentioned as**  **being visually**  **di scernible**  **by the**  **human eye**  **("causing haze").**  **Ther ef**  **ore, a**  **visibil ity**  **impr**

**ovement less than**  **0.3 de lta-deciview**  **should be**  **considered as**  **being too**  **small to**  **distinguish from**  **no change**  **in visibili** **ty what** **soever (and**  **is well**  **below the**  **"contribution" and**  **"cause" thresholds**  **in the BART**  **Rule), so**  **it can**  **also be**  **consid ered**  **as insigni** **ficant for**  **consid eration**  **as BART**  **control option**  **to be**  **adopted. 5.3.2**  **Vi sibili** **ty Impr** **ovement Cost**  **Effec tivene** **ss As**  **noted above,**  **EP A BART**  **reg ulations**  **do not**  **est ablish**  **specific thr**  **es holds**  **for cost-effec** **tiveness. However,**  **the Federal**  **Land Man** **agers (FLMs),**  **in numer**  **ous corre** **spondences 2**  **1 to**  **states, have**  **refe rred**  **to a**  **benchmark of**  **$20 million**  **per deciview**  **as a**  **threshold for excessively hi** **gh costs**  **for the**  **degr ee**  **of visibi**  **lity impr**  **ovements. This**  **metric is**  **computed by**  **dividing the**  **annua lized**  **cost of**  **the control**  **(re lative**  **to a**  **ref erence**  **case such**  **as baseline**  **conditions or**  **another BART**  **option) divided**  **by the**  **981h percentile day's**  **visibili ty**  **impr ovement**  **relative to**  **the ref**  **erence case,**  **averaged over the**  **years modeled.** 

**17 EPA**  **Federal Register**  **I Vol.**  **77, No** **. 164**  **f Thursday,**  **August 23, 201**  **2/ Rules**  **and Regulations,**  **page 50938.**  **18 Tombach,**  **1., 2002.**  **Implication of**  **Aer osol**  **Measurement Uncertainty**  **on Tracking**  **of Progress in**  **Mitigating Regional**  **Haze. Paper**  **# 42 617** 
**. Presented**  **at the**  **95th Annual**  **Conference and**  **Exhibition of the**  **Air &**  **Waste Management**  **Associ ation.**  **Baltimore, MD**  **. Available**  **at htt**  **p :** **/ /IMvvv** **.atm osp** 

**heric**

**- research** 

**. com** **/ PDF**  **s Nisibil**  **itvTr acking.pdf** 
**. 19**  **Papp, M.,**  **201 2.**  **Documentat ion of**  **Measurement Uncertainty Estimates**  **of Collocated**  **Chemical Speciation**  **Network and IM**  **PROVE Data**  **for Use**  **in the**  **Secondary PM2**  **s Standard**  **for Visibility. Ava**  **ilable at**  **http /** **fwv.tvv. epa**  **.**

**go v/tt**  **nnaa**

**gs /s** **tandards/**

**p m/data/20**  **1 2 0613P** **app. pdf** 
**. 20**  **Page 40**  **of the Arizona**  **Regional Haze Rule**  **State Im**  **plementation Plan,**  **available at**  **http://w.Nw.azdeq.go v/** **environ/a i**  **rlhaze/d ownloa** **d lhaze3**  **08 sip.pdf** 
**. 21**  **See h** **ttp: /fwv.tvv** **.na ture.n**  **p s**  **. go** **v/a i** **r/regs/sipletters/odf/ Pe**  **nnsyl v** **an i**  **a 08** **- 02-** **2010. pdf** **, http://w.Nw.**  **natur**

**e.nps.g ov/air/** **regs/sipletters/txlf/Nevada EPA**  **Letter 08** **-17 -2** **01 1**  **.pd f** **, and**  **http :** **/fwv..w .dec.**  **st ate.**  **ak .us** 

**/AI R!ap/docs/** 

**GVEA%20 B** **ART%20 N**  **PS% 20Comm**  **e nts%206-15-** **09 .odf** **. Visibility**  **Impr**

**ovement Analysis**  **for Candidate**  **BART Control**  **Options :**  **Sundt Unit 4**  **May 2** **0 1**  **3 AECOM**  **Environment**

**5.3.3 Vi**  **sibil ity**  **Modeling Re** **sult s**  **The results**  **pr esented**  **in this section**  **indica te**  **that both**  **candida te**  **controls result**  **in visibili** **ty impr**  **ovements well**  **below 0.3**  **delt a-deciview**  **at the**  **Saguar o**  **National Park.**  **Therefore, the**  **visibili ty**  **impr ovements**  **are too**  **low to**  **be consider**  **ed as BART**  **jus t**  **due to**  **their very**  **small magni** **tudes, which**  **are themsel** **ves overstated**  **due to**  **ammonia slip**  **which was not**  **consid ered**  **in the conservative**  **CA LPUFF**  **version 5.8**  **modeling. 5-4** 

**The largest**  **visibili ty**  **bene fits**  **at the Sagu**  **aro National**  **Par k**  **for the**  **DSI/SNCR and**  **DFGD /SCR**  **controls are**  **0.16 2**  **and 0.12** **8 del** **ta-dv, respectively.**  **TEP has**  **pr ovided**  **annual ized**  **cost in** **fo rmation**  **for these two**  **control options as**  **foll ows**  **:**
**• DSI**  **+ SNCR:**  **$ 6,1**  **59,9 54** 

**• DFGD**  **+ SCR:**  **$ 27,1**  **30,657 The**  **resulting visibili** **ty cost -effect** **iveness metrics**  **are, ther**  **efore, about**  **$38,000, 000/dv**  **for DSI/SNCR**  **and about**  **$21 2,000,000**  **for DFGD** **/SCR. These**  **visibi lity**  **cost-e ffe** **ctiveness values are well**  **above the**  **bench mark**  **value of**  **$20,000, 000/dv,**  **especially Option 2**  **(DFGD /SCR).** 

**Visibility Impr** 

**ovement Analysis**  **for Candidat**  **e BART**  **Control Options :**  **Sundt Unit**  **4 May**  **20 13** **AECOM Environment**  **6-1**



### 6.0 **Conclusions**

**The Uni** **ted States**  **Environmental Protec**  **tion Agency**  **(EP A)**  **Region 9**  **is anticipa** **ted to**  **foc us**  **in the**  **near future**  **upon a**  **Best Av** **ailable Retrofit**  **Technology (BART) ev** **aluation fo** **r the**  **Sundt Unit**  **4, which**  **can be**  **fired with**  **either coal**  **or natural gas**  **and is**  **located in**  **Tucson, Arizona.**  **Tucson El**  **ectric Power**  **(TEP) does not**  **bel ieve**  **Sundt Un**  **it 4 is**  **BART eligible,**  **however, TEP**  **has asked**  **AECOM to**  **pr ovide**  **a compar** **ative visibili** **ty assessment**  **for two emission**  **control options**  **for this**  **coal-fired uni** **t:**

**• Option**  **1: S02**  **control using**  **dr y**  **sorbent in** **jection (pr** **ov iding**  **70% control**  **over the**  **baseline emission**  **ra te),**  **and NOx control**  **using Se** **lective Non-Catalytic**  **Reduction (pr** **ov iding**  **30% control**  **over the**  **baseline emission rat** **e)**
**. •**  **Option 2: S02 control**  **using dr**  **y flue gas**  **desu lfurization**  **("dr y**  **scrubbing", provid**  **ing 89%**  **control effi** **ciency) ,**  **and NOx control**  **using Selective**  **Catalytic Reduction**  **(pro viding**  **89% control**  **eff iciency).**  **AECOM has**  **conduc ted**  **new modeling with the**  **fo llowing**  **changes from**  **EP A's**  **mode ling:** 

**• Upda** **ted exit**  **veloci ty**  **for Unit**  **4 was modeled**  **based on**  **rev ised**  **stack measu**  **rements provided**  **by TEP.**  **The exit**  **velocity TEP**  **provided was**  **about 34%**  **higher than**  **EPA used.** 

**• TEP**  **estimated a**  **rev ised**  **(70%) control**  **efficiency for**  **the dr**  **y sorbent**  **injection (OS**  **I) S02**  **emission contr** 

**ols, slightly**  **lower than**  **what EPA**  **used (75%).**

**• Based**  **upon newly available**  **ammonia measurement**  **in form**  **ation, AECOM**  **used as**  **input to**  **CALPUFF a**  **set of**  **monthly -v** **arying ammonia**  **background con** **centrat ions**  **that correspond**  **to the**  **actual measur** **ed values**  **during winter**  **at a**  **Class I**  **area being**  **modeled in**  **southern Arizona,**  **which range**  **from 0.5 to**  **1 . 0**  **ppb. EPA had**  **appli ed**  **a 1 .**  **0 ppb**  **ammonia value**  **fo r**  **all months**  **of the**  **year. The**  **visibili ty**  **impr ovement**  **modeling review**  **was conduc** **ted for all Prevention of**  **Signi ficant**  **Deterioration Class I**  **areas within**  **300 km**  **of the**  **plant, using**  **the CALPUFF**  **model version**  **5.8. This**  **model has a known**  **over-p rediction**  **bias for**  **ni trate**  **haze form**  **ation that**  **overstates the**  **visibility impr** **ovements for**  **the cand**  **idate BART**  **options. The**  **modeling also**  **does not account for**  **the haze**  **causing effe** **cts of**  **ammonia slip**  **from the**  **NOx emission**  **controls that**  **were evaluated.**  **Even with**  **these over-p**  **rediction biases,**  **the resu**  **lts of**  **the analysis**  **ind icate**  **that the**  **only Class**  **I area**  **with 98** **th percentile**  **daily im**  **pacts above**  **the BART**  **scree ning**  **level of**  **0.5 del** **ta-deciview is**  **Saguaro National**  **Park. At**  **this park,**  **the candida** **te controls result in levels**  **of visibili** **ty impr** **ovement that**  **are too**  **low to**  **be detected**  **(or distingui** **shed from**  **no change**  **in haze)**  **by the**  **available technology**  **for particu**  **late mon** **itors (well below the**  **detection threshold**  **of 0.3**  **del ta-decivie** **w) and**  **are less**  **than 20%**  **of the**  **per**

**ceptible levels**  **that can**  **be visually**  **detected (1**  **deciview). Fu**  **rthermore, the**  **cost eff**  **ectiveness of**  **both control**  **options is**  **hi gher**  **than the**  **Federal Land**  **Manager -estab**  **lished benchm**  **ark of**  **$20 milli** **on/dv. Accor** **di ngly,**  **we conclude**  **that neither**  **of these**  **control options**  **would provide**  **cost eff**  **ective visibili** **ty impr** **ovement and**  **ther efore**  **based on**  **the EPA's**  **criteria, it**  **is not**  **re asonable**  **to require**  **additional controls**  **of S02**  **or NOx**  **at Sun**  **dt Uni** **t 4.** 

**Visibility Impr** **ovement Analysis**  **for Candidate**  **BART Control**  **Options :**  **Sundt Unit**  **4 May**  **20 13** **AECOM Environment** 



### Appendix **A Vi**  **sibili ty**  **Model ing**  **Res u**  **lts fo**  **r All**  **C l ass**  **I Ar** **eas**

**Visibil ity**  **Im provement**  **Analysis for**  **Candidate BART**  **Control Options**  **: Sundt Unit**  **4 May**  **2013 AECOM**  **Environment**

**Table A-1**  **98th Percentile**  **CALPUFF Modeling**  **Result s** * **for Visibili** **ty Im**  **pairment, delta-deciview**  

### Option **1 Option**  **2 Class**  **I** 

### Area **Baseline Uni** **t 4 Uni** **t 4 SNCRIDSI**  **SCRIDFGD Ma** **zatz ai**  **W 0.0** **4 0.02**  **0.02 Gila**  **W 0.0** **8 0.0** **4 0.03**  **Mt. Baldy**  **0.0 5**  **0.03 0.02**  **Galiur o W**  **0.45 0.33**  **0.25 Sier** **ra Ancha**  **0.0 6**  **0.03 0.0** **2 Su**  **perstition W**  **0. 12**  **0.0 6**  **0.0 4**  **Pine Mountain**  **W 0.0** **3 0.02**  **0.01 Chir** **icahua W**  **0. 18**  **0. 11**  **0.0 8**  **Ch iricahua**  **NM 0.1**  **9 0.12**  **0.08 Sagu**  **aro East**  **NP 1 .**  **37 1 .**  **21 1 .**  **24 Sagu**  **aro West**  **NP 1 .**  **01 0.86**  **0.85**
**• '"**  **' .** **. ..**  **. . 98**  **percentile day**  **s VISibi**  **lity 1mpa1rment**  **over 3**  **years modeled,**  **relative to**  **natural cond1t1ons**  **Table A-2:**  **Visibil ity**  **Imp rovement** * **over Baseline**  **Conditions, delta-deciview** 

**•** 

### Visibil **ity Visibil**  **ity Im**  **provement for**  **Impr ovement**  **for Class**  **I** 

### Area **Option 1:**  **Option 2:**  **SNCRIDSI SCRJDFGD**  **on Uni** **t 4 on**  **Uni t 4**  **Ma zatz** **ai W**  **0. 019**  **0.028 Gi**  **la W**  **0.038 0.05** **4 Mt.**  **Baldy 0.020**  **0.029 Galiur**  **o W 0.**  **1 2 5**  **0.203 Sier** **ra Ancha**  **0.028 0.038**  **Super stition**  **W 0.05** **4 0.073**  **Pine Mountain**  **W 0.**  **013 0.**  **019 Chir** **icahua W**  **0.063 0** 
**. 1 0** **0 Chir** **icahua NM**  **0.069 0.**  **1 1 2**  **Sagu aro**  **East NP**  **0. 1 6** **4 0.12** **8 Sagu**  **aro West NP**  **0. 1 4** **7 0.**  **1 6 2** **m I** **0 • •** **• 98**  **perce ntile**  **day s**  **VISibili ty**  **1mpa1rment over**  **3 years**  **modeled**

**Visibility Improvement**  **Analysis for Candidate**  **BART Control**  **Options :**  **Sundt Unft**  **4 May**  **20 13** 

# ATTACHMENT **E 1 2** **0.0**
**110 .0** 
**1 0 0.0** 
**90.0**
**- (,)**  **Cl)** 

# � **80.0 >-**  **.... ·c:;**  **0 a;**  **70.0 >**  **� (,)**  **Ill ....**  **en 60.0** 
**50.0**
**40.0**
**30.0 30**  **40 50**  **60** 

### Sund**t Uni** **t 4**  **-** 

### Stack **Ve locity**  **vs Load** 

**70 80** 

**Load** 

### (MWe) **90 1 0** **0 110**  **1 2 0**  **1 3 0**