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HomeMy WebLinkAboutAQ_F_0400056_20211221_ST_WaiverResp ROY COOPER Governor ELIZABETH S.BISER Secretary MICHAEL ABRACZINSKAS NORTH CAROLINA Director Enykwwwat+ol QuaUty December 21, 2021 Adam Long VP, Gas Pipeline Operations Piedmont Natural Gas 410 South Wilmington Street Raleigh,NC 27601 Subject: Approval of Waiver Request for Emissions Testing of One Natural Gas Engine as Representative of Four Engines COMP01-COMP04 Piedmont Natural Gas-Wadesboro Compressor Station Wadesboro,Anson County,North Carolina Facility ID No. 0400056;Air Permit No. 10097T02 Dear Mr. Long: The North Carolina Division of Air Quality(NC DAQ)has reviewed the information submitted in your company's letter dated September 22,2021,requesting a waiver from the performance testing requirements of 40 CFR 60 Subpart JJJJ-Standards of Performance for Stationary Spark Ignition Internal Combustion Engines,as related to four identical,natural gas-fired,internal combustion engines(Permit ID Nos. COMPOI through COMP04)at the Piedmont Natural Gas-Wadesboro Compressor Station(PNG- Wadesboro). PNG-Wadesboro is requesting to conduct performance testing on one of the four engines as representative of emissions from all identical engines on site to demonstrate compliance with the 40 CFR 60 Subpart JJJJ testing requirements. 40 CFR 60 Subpart JJJJ requires periodic testing of subject engines once every three years or every 8760 hours of operation,whichever occurs first.Upcoming performance testing during calendar year 2022 will be conducted to meet the three-year testing requirement since the engines at the PNG- Wadesboro site operate less than 8760 hours in a three-year period. Pursuant to 40 C.F.R. § 60.8(b)(4), performance tests shall be conducted in accordance with the test methods and procedures contained in each applicable subpart unless the Administrator(NC DAQ in this case)waives the requirement for performance tests because the owner or operator of a source has demonstrated by other means to the Administrator's satisfaction that the affected emission source can continually comply with the standard. Section V11.2 of the US EPA's April 27, 2009, Clean Air Act National Stack Testing Guidance states that a performance test waiver for identical emissions units may be appropriate when the following conditions are met: I. the units are located at the same facility; 2. the units were produced by the same manufacturer,have the same model number or other manufacturer's designation in common,and have the same rated capacity and operating specifications; 3. the units are operated and maintained in a similar manner; and 4. the EPA or delegated agency,based on documents submitted by facility: a. determines that the margin of compliance for the identical units tested is significant and can be maintained on an ongoing basis;or D J4 North Carolina Department of Environmental Quality I Division of Air Quality E 217 West Jones Street 1 1641 Mail Service Center I Raleigh,North Carolina 276 1 = � 9h, a 99 641 �"�' .r 919.707.8400 Piedmont Natural Gas-Wadesboro Compressor Station December 21,2021 Page 2 b. determines based on a review of sufficient emission data that,though the margin of compliance is not substantial, other factors allow for the determination that the variability of emissions for identical tested units is low enough for confidence that the untested unit(s)will be in compliance.These factors may include,but are not limited to,the following: i. historical records at the tested unit showing consistent/invariant loads; ii. fuel characteristics yielding low variability and therefore assurance that the emissions will be consistent and below allowable levels; and iii. statistical analysis of a robust emissions data set demonstrates sufficiently low variability to convey assurance that the margin of compliance,though small, is reliable. In reviewing performance testing waiver requests for identical emission sources,NC DAQ must first ensure that the criteria outlined above from the US EPA's Clean Air Act National Stack Testing Guidance are met fully and continuously.Beyond this,NC DAQ may specify additional requirements on facilities to ensure all emission units are tested over time on a regular schedule and to ensure continuous compliance with the applicable emission standard(s)for all units. To support the request for testing one engine as representative of COMPOI through COMP04, PNG-Wadesboro provided information on the manufacturer,model number,rated capacity, and operating specifications for all four engines,as well as analyses of historical emissions data,loads, and run times for the subject engines.Based on the information provided,the four engines appear to be identical and are being operated and maintained in the same manner with uniform fuel characteristics. The emissions data reported for this facility since 2013 demonstrates a significant margin of compliance(greater than 50%) for all regulated pollutants. Therefore,NC DAQ approves the requested waiver of performance testing for identical units at the PNG-Wadesboro site on an ongoing basis,provided that the following conditions are met: 1. Two engines of the set COMP02 through COMP04 are tested in 2022 and the third of this same set is tested in 2024; 2. A different engine is tested every other year with two engines being tested every fourth year to ensure regular testing over time and that all engines are tested at least once every six years after 2024(e.g.,test COMP02 and COMP03 in 2022,COMP04 in 2024, COMPOI and COMP02 in 2026,COMP03 in 2028, and repeat cycle going forward); 3. If any engine approaches 8760 operating hours since the last representative performance test, a new representative test is conducted prior to passing the 8760-hour threshold; 4. All new performance test results continue to meet the waiver criteria outlined above from the US EPA's Clean Air Act National Stack Testing Guidance. A justification and supporting data for continuation of this waiver should be included in each performance test report that is intended to provide representative emission results for multiple identical engines on the same site; and 5. All future protocol submittals for representative testing of identical units include references to this approval letter and to the most recent justification and supporting data for continuation of this waiver. If future test data does not support requirements to maintain classification of the engines as identical,PNG-Wadesboro may be required to perform additional testing.NC DAQ will review the facility's continual adherence to the criteria for performance test waivers for identical emission units by reviewing the justification and supporting data that is submitted with each future performance test report. Piedmont Natural Gas-Wadesboro Compressor Station December 21,2021 Page 3 This performance test waiver does not exempt the facility from complying with other applicable requirements of 40 CFR 60 Subpart JJJJ,other state or federal air quality regulations, and their air permit. In addition to the mailing of this letter, an electronic copy(e-copy)is being provided for your records. If you have any questions regarding this waiver approval,please contact Taylor Fort of my staff at 919-707-8431 or taylor.fort@ncdenr.gov. Sincerely, Stephen G.Hall Chief,Technical Services Section Division of Air Quality,NC DEQ cc: Kristen Belisario, Piedmont Natural Gas(e-copy) Heather Carter,FRO Air Quality Supervisor(hardcopy and e-copy) Gary Saunders, SSCB Supervisor(e-copy) IBEAM Documents—0400056