Document Nkbp7e7d1NvdRqzwMaEYo1wp

The Rule will impose significant costs that would jeopardize the future use of lignitefired units and imperil grid reliability. In the near term, the Coyote Station owners W ould need to expend approximately $100,000 per month to conduct longer-term mercury testing. This testing would need to occur over multiple months to determine if compliance can he achieved -- compounding the costs of this endeavor. The testing Would need to occur later this year (2025) and continue in 2026. Granting this exemption would avoid these costs if EPA were to reconsider the MATS RTR and provide relief from the 1.2 lbiTritu standard for lignite units. In addition, Coyote Station has budgeted to install mercury CEMS in 2026, at a cost of $500,000, to monitor mercury with more real time data during the testing. Indeed, the MA IS RTR does not account for these types of costs associated with mercury testing, monitoring, and the PAC supply chain deliveries necessary for increased sorbcnt injection. Based on this information, Otter Tail and the Co-owners conclude that the technology to meet the mercury standard is not available. Therefore, the MATS RTR is potentially queued to directly impact the future availability of Coyote Station, a critical lignite asset. Accordingly, Coyote Station should be granted a two-year exemption. IV. PM CEMS Are Not Technologically' Able to Assure Compliance with the Revised PM Standard The MATS RTR requires the installation of PM CEMS to demonstrate compliance with the revised 0.010 lb/MMBtu PM standard. Coyote Station has achieved LEE status under the current rule and complies with MATS using periodic PM stack testing. PM CEMS are not installed at Coyote Station. For the reasons identified below, CEMS arc not a technology that is available due to inaccuracies and correlation challenges at low PM levels. The accuracy of PM CEMS at low PM emissions levels is not proven. PM CEMS do not directly measure PM omissions. In other words, the instrument does not measure the mass of PM and the volume of flue gas from which that mass of PM was sampled. Instead, commercially available PM CEMS measure some property (i.e., light scatter or beta attenuation) that must be correlated to actual stack PM measurements. [9 At lower emissions levels, PM CEMS have not been demonstrated to have the sensitivity needed to accurately account for lower emissions levels. Technological feasibility has not boon proven at low PM omissions levels?' Due to the indirect measurements, PM CEMS correlation testing must ensure the measurements arc true to the actual f-PM emission rates.'' But the low PM standard in the Rule makes developing this correlation curve "virtually impossible."22 Similarly, the Quality 'I he EPA statement at 88 Fcd. Rcg. at 24872, that a beta gauge "detector measures the amount of radiation emitted by the sample" is categorically incorrect and illustrative of several uninthrmcd statements (c.g., cost cstimatcs) about PM CEMS in the preamble to the proposed rulc. See PGE.V EPA 's Proposed Rule. NESI P roar and Oil-Fired Neu'nu 1-1 iy learn Generate,+g Dais Review of he Residual Risk and "TeuhnoIogy Review, Docket No EPA-I IQ-OAR-2018-0794-5994, at 22 (Junc 28, 2023) (KiEN Comments) (citing and attaching Ralph I. Roberson, 'Technical Coninienis r)n EPA 's Proposed Rule fercury and A ir Toxics Sfamiards Risk and 'Teuhnologr Review, at 3 (2023) (PM CEMS Technical Memo)) 2 ' hi Icl Sierra Club FOIA 2025-EPA-04883 ED_018388_00000194-00006 SC_EVERSPLIT0005969