Document g5vMkgw939VXxxwk9GxoG4YN

Assurance/Quality Control (QA/QC) criteria for CEMS are extremely difficult to meet at such low levels. 23 At the time of the proposed rule, no commercially available PM CEMS would have been able to meet the tight confidence and tolerance intervals associated with the low proposed PM standard EPA was, thus, forced to address these issues in the final MATS RTR by adjusting the QA criterion and correlation procedures.-'' These changes are not enough to address the fundamental issue that PM CEMS arc simply not able to reliably measure such low PM levels -- the error rates of the instrument prohibit it.'' Therefore, the CEMS technology to demonstrate compliance with the new PM standard is unavailable. Coyote Station has been able to demonstrate very low PM emission rates with its current control technology. It initially demonstrated compliance via quarterly stack testing. After meeting the criteria to attain LEE status under the MATS Rule for PM, Coyote Station has demonstrated compliance on an every 3-year basis. Coyote Station cannot demonstrate compliance using PM CEMS because CEMS cannot reliably verify the low levels of PM that would comply with the new standarci. 21 Furthermore, there are high costs associated with procuring, installing, certifying, testing, and operating PM CFMS.28 Assuming that the technology would somehow he feasible to install, Otter Tail and the Co-owners have budgeted 5400,000 to install PM CEMS in 2026 at Coyote Station. Granting this exemption would avoid these costs if EPA were to reconsider the MATS RTR and provide relief from the PM CEMS requirement. Finally. PM CEMS must be installed and tested by vendors that are certified, and there arc only a limited number of vendors that arc available. As two-thirds of coal-fired EGlis have not yet installed PM CFMS, the MATS RTR requirement will overwhelm the current supply of PM CFMS and the availability of vendors to perform the necessary work.29 For these reasons, and because CEMS technology is unavailable at low PM levels. Coyote Station should receive a two-year exemption for compliance with the CEMS requirement in the MATS RTR. See Conunenis of the Cla of '85 Regulators. Respome Group on the Propmal on .Vannal Enuion Standard.% for Hazardous Alr Pollulants: Coal- and Oil-Fired Electric t 'tility Steam Generating t nits Revieit of the Retclual Rik ami Technolo,,ry Revult, Docket No. EPA-HQ-OAR-2018-0794-5989, at 16 (June 28. 2024) (Class of '85 Comments). PM GEMS Technical Memo at 5. See 89 Fed Rcg at 38528-29. See KiEN Comments at 23 (finding insurmountable thc "uncertainties inherent thc in thc measurement device" and thc "problems associated with relative si7c of the uncertainty to the limited data range of fPM concentrations and thc confidence levels and tolerances"); w' aise Class of '85 Comments at 18. See Otter Tail Comments at 1() See P(11-.N Comments at 26: we rdso Class of '85 Comments at 18 (cstimatin2 $180,000 to $400,000 for - site preparation and engineering analysis, analy7er equipment and installation costs, and initial PS-11 correlation testing L See Class of '85 Comments at 16. 7 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000194-00007 SC_EVERSPLIT0005970