**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 sub mittal 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 unit
specific 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 l ight 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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2. Document and include in the protocol the applicable hourly emission rate information for PM 10, H2SO4 (condensable particulate), and PM 10 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 PM 10 emissions must be modeled for EGUs. As recommended per the VISTAS BART protocol, facility stack test emissions, potential to emit emissions, and permit all owable emissions may be utilized in lieu of the actual emissions rate. The emission estimates utilized must be defensible and documented in the protocol. Response: T

he 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 -1 default 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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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 22 nd highest prediction over the th ree 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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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. Res ponse: 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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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