Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402-2801

July 28, 2006

Mr. Martin Luther

Kentucky Department for Environmental Protection

Division for Air Quality

803 Schenkel Lane

Frankfort, KY 40601

Dear Mr. Luther:

REVISED BART MODELING PROTOCOL FOR TVA PARADISE FOSSIL PLANT

Enclosed is the revised best available retrofit technology (BART) modeling protocol for the Tennessee Valley 

Authority (TVA) Paradise Fossil Plant (PAF). Your comments on the original submittal have been addressed, and 

responses are summarized below:

KYDAQ Comments on TVA Protocol

1. KYDAQ recommends that TVA Paradise BART Modeling Protocol be revised to be structured in a 

modeling protocol format to provide modeling details, such as: Cover page; Table of contents; a 

Modeling Introduction with modeling objectives, location description and maps of the modeling 

domain with the source and relevant Class I Areas; Source description and emissions data with unitspecific data; CALPUFF Model Input data with general modeling procedures, air quality database 

(background ozone and ammonia) and natural conditions and monthly f(RH) at Class I Areas; and Air

quality modeling procedures with model selection and features, modeling domain and receptors and 

light extinction and haze impact calculations; Modeling results; References; and Appendices to 

provide unit-specific emissions data for modeling and other relevant information. Please provide 

KYDAQ with the revised protocol. 

Response: In the BART meeting on 19 April 2006 between KYDAQ and UIEK, protocol format was 

discussed briefly. Our understanding from that meeting was that the format of our original submittal 

would be acceptable. However, we have reformatted and revised the PAF modeling protocol to

address this comment.
Mr. Martin Luther

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July 28, 2006

2. Document and include in the protocol the applicable hourly emission rate information for PM10, 

H2SO4 (condensable particulate), and PM10 speciation emissions to be modeled for the TVA 

Paradise BART-eligible units. Please note that since CAIR equals BART for SO2 and NOx for EGUs, 

only PM10 emissions must be modeled for EGUs. As recommended per the VISTAS BART protocol, 

facility stack test emissions, potential to emit emissions, and permit allowable emissions may be 

utilized in lieu of the actual emissions rate. The emission estimates utilized must be defensible and 

documented in the protocol. 

Response: The emission rates to be modeled are discussed in Section IV of the revised protocol. 

The emission values are included in the attached Excel workbook, PAF_CY05_BART.xls, under the 

tab labeled “BART.”

3. In order for KYDAQ to properly review the emission rate information, provide KYDAQ with the hourly 

PM10, H2SO4, and PM10 speciation emissions in an electronic format when the data is available.

Response: Emission rates and calculations are enclosed in the attached Excel workbook, 

PAF_CY05_BART.xls.

4. Barring any change in the recent agreement reached with EPA and an [sic] utility group, the KYDAQ 

will accept natural background light extinction corresponding to either the 20% best days or the 

annual average haze index value (dv) (EPA 2003).

Response: TVA proposes to use annual average values in the PAF BART evaluation (see Section 

II).

5. Recently, VISTAS has decided to utilize the .5 ppb default for the background ammonia value with 

POSTUTIL for ALM for fine grid modeling.

Response: This approach is discussed in Section II of the revised protocol.

6. Using a Rayleigh Scattering value other than the 10 Mm-1default or using any of the other revisions 

proposed by the IMPROVE subcommittee to determine natural conditions is not recommended by 

EPA at this time. KYDAQ and the FLMs defer to this EPA comment.
Mr. Martin Luther

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July 28, 2006

Response: This approach is discussed in Section II of the revised protocol.

7. The protocol should reflect that for the for the 4-km modeling that the 98th percentile modeled value 

(8th highest) per year or the 22nd highest prediction over the three years modeled, whichever is 

greater, will be compared to the .5 dv contribution threshold. 

Response: This approach is discussed in Section II of the revised protocol.

8. The protocol should indicate that if the source is found to cause or contribute to visibility impairment 

then the source will proceed to perform BART determination modeling for the baseline and each 

control option in accordance with the VISTAS BART Modeling Protocol.

Response: This statement is repeated in Section II of the revised protocol.

9. Include stack parameters to be modeled in the modeling protocol and provide them to KYDAQ. See 

EPA’s comment that GEP Stack Height must be modeled and documented in the protocol.

Response: Stack parameters are listed in Section IV of the revised protocol. Note that all stacks 

currently in service for the PAF BART-eligible units were built before 12-31-1970. As a result, GEP 

stack requirements do not apply. If exemption modeling shows that Unit 3 is subject to BART, the 

new scrubber stack will be modeled using GEP guidelines.

EPA Region 4 Comments on TVA Protocol

One of the most important factors in any modeling exercise is to ensure that the source 

parameters (e.g., emission rates, stack parameters) are correct. EPA Region 4 

recommends that the Kentucky Division of Air Quality carefully compares these 

parameters with existing permits and databases to ensure that appropriate values are 

being used for the BART modeling.

1. Good Engineering Practice (GEP) Stack Height: The protocol should be revised to discuss how GEP 

stack height will be determined and used in the CALPUFF modeling. The stack heights used in regulatory 

air dispersion modeling must not be greater than the GEP stack height as determined in accordance with 

Chapter 40 of the Code of Federal Regulations (CFR) Part 51. 
Mr. Martin Luther

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July 28, 2006

Modeling with stack heights that exceed the GEP stack height constitutes a prohibitive dispersion

technique. The Enclosure to TVA’s January19, 2006, letter to KYDAQ indicates that all 3 units that will be 

modeled have stack heights greater than the de minimis GEP height of 65 meters. The protocol should 

provide a detailed justification that the stack heights listed in the table represent GEP for these sources.

Response: See Response #9 in the section above.

2. The protocol should be revised to provide maps showing the location of the TVA facility and the Class I 

areas that are within 300 km from the sources being modeled. 

Response: The location and map are included in Section III of the revised protocol.

NPS Comment on TVA Protocol

We recommend that all protocols follow the VISTAS Regional Planning Organization 

modeling protocol “Protocol for the Application of the CALPUFF Model for Analyses 

of Best Available Retrofit Technology (BART).” The National Park Service accepts 

the VISTAS protocol, and we assume the Kentucky BART eligible sources will follow 

this protocol. The National Park Service will provide advice for Particulate Matter (PM) 

speciation. Speciation information and worksheets are available on our website at:

http://www2.nature.nps.gov/air/permits/ect/index.cfm

We ask that the Kentucky Department of Environmental Protection verify emission rates for each source. We also 

ask to see the results of the PM speciation before the State approves the modeling protocol.

Response: As stated in our original submittal, the VISTAS protocol will be followed for PAF BART modeling. 

Speciation data from the NPS are included where appropriate.
Mr. Martin Luther

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July 28, 2006

If you have questions, please contact Elizabeth Bailey at embailey@tva.gov or 256-386-3645.

Sincerely,

Original signed by

Steve Strunk for

Gordon G. Park

Manager, Environmental Affairs

5D Lookout Place

Enclosures