Document gDYNamMvmGZ95aapMKb4pg67N

r TALEN ell MONTANA reduced fl'M emissions, which could bias the data set low. EPA should exclude data from units that co-fire natural gas in evaluating what a revised fi'M standard should be. Any proposed fi'M limit that EPA establishes should be based on fPM from affected units that only combust coal. Lastly, EPA's evaluation is replete with questionable assumptions and statements. For instance, in the technical reports developed by Sargent & Lundy ("S&L"), on which EPA relies for cost and emissions reductions assumptions, S&I. acknowledges that "[biased on S&I,'s recent industry experience, the lowest filterable PM emission rates that an ESP supplier has been willing to guarantee is 0.030 lb/MMBtu for a new and/or completely rebuilt ESP."'' Yet, the study states that "it is clear that emission levels down to 0.010 lb/MM13tu and below are achievable in most ESP applications based on the reported emissions data" despite acknowledging that the authors arc unable to tie a specific performance improvement to a specific set of ESP upgrades.37 EPA should not rely on such unsupported statements to justify a fl'M limit of 0.010 lb/MM13tu. h) EPA'sfPMproposal disproportionately impacts Colstrip. EPA's proposal to tighten the fPM limit also is arbitrary and capricious because it disproportionately impacts Colstrip. Even if EPA were correct that most units subject to the Proposed Rule would have to do nothing and that the remainder would only need to upgrade existing control technology, the same is not true for Colstrip.3 As EPA acknowledges in the proposal, Colstrip would need to install new ESPs or FFs -- and the Colstrip units, based on EPA's analysis, would be the only two units that would need to do so to comply with the proposed 0.010 lb/MM13tu fl'M Given that EPA's rationale for the Proposed Rule is that existing control technology is more effective and cost effective than was known at the time of the original MATS rule -- that 91% of units already have either a FF or ESP and arc meeting the proposed standard and that the rest would only need to upgrade existing control technology at relatively low cost it simply does not follow that Colstrip should be required to install new, complex, and prohibitively expensive control technology to meet a significantly lower standard.`() The logical conclusion that should flow from EPA's rationale (assuming that it is not flawed), is that Colstrip should upgrade its existing venturi wet scrubber technology to the greatest extent possible. Instead, EPA proposed that Colstrip should meet the proposed standard by installing new FFs or ESPs at Colstrip. Below is a table summarizing the total annuali7ed cost and the annuali7ed Sargent & Lundy PM Incremental Improvement Memo, I)oc II). EPA-IIQ-OAR-2018-0794-5836 at 2 (Mar 2023). See a/so Technical Memo at PI)F p 8 PM Incremental Improvement Memo at 2 See Technical Memo at PI)F p 9-10. See id. at PI)F p. 10 For the one facility with existing venturi -type WS (and without an existing ESP or FF), EPA assumes that ESP upgrades will reduce fl'M emission to 1 5E-02 1b 1 MMIltu. -To achieve the lower potential standards, EPA assumes that these I-GUs would require FF installation, reducing baseline fl'M rates by 90% subject to a floor of 2.0 F-03 " (emphasis added)). '4(> 88 Fcd Reg at 24,868: Technical Memo at PI)F p 9-10. 13 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000307-00014 SC_EVERSPLIT0006110