Document Yj6oyXQRw75XB1By1Mq6aM07k

complete rebuild of the ESP. It is possible installation of a new baghousc would be necessary to meet the revised standard under all operating conditions. However, this technology is not available because it is designed and installed on a site and facility specific basis and is cost-prohibitive. A new baghouse would cost 5150-360/kW to install, which does not include operating costs. Ralph L. Roberson, Technical Comments on EPA's Proposed Rule: Mercury and Air "taxies Standards Risk and Technology Review, Docket No. EPA-HQ-OAR-2018-0794-5994, at 3 (2023) [hereinafter "PM CEMS Technical Memo"]. Additionally, other issues exist regarding the installation of a new baghouse, including the space needed for the large footprint a new baghouse requires. We are unaware of any other available particulate control technology that would be cost effective and satisfy space constraints. Miami Fort's operational limitations could also hinder the ability to continuously comply with the fPM standard. Although some units may be able to achieve a rate of 0.010 lb/MMBtu under certain conditions, the Rule requires continuous compliance. Even units that can achieve the limit in ideal conditions may not be able to continuously meet that limit during peak load conditions when they cannot do off-power rapping or maintenance and cleaning of PM controls. During the summer, most units operate at base load and run at high-capacity factors. It may be difficult to maintain optimal operation of control technologies during peak summer conditions unless there are additional outages scheduled for such maintenance, which may not always be feasible. Moreover, the characteristics of coal vary depending on location. Ash content of the coal being fired may impact the ability of units to comply with the fPM limit, regardless of the effectiveness of the control technologies in place. Other operational factors such as cleaning frequency, operational duration, and maintenance frequency may impact the performance of ESPs and a facility's ability to comply with the proposed limit. These concerns arc exacerbated by the companion requirement to measure compliance using monitors that have not been demonstrated to be reliable. II. CEMS Technology is Not Available The MA FS MR requires coal-fired units to implement the revised [PM standard using CEMS, rather than periodic stack testing. As explained above, this requirement is an integral part of the numeric limit itself. Miami Fort does not have PM CEMS and has historically utilized quarterly stack testing to demonstrate compliance with the fPM standard. There arc technological limitations, as well as costs and market limits, that make adoption of. CEMS by July 2027 unattainable. PM CEMS does not provide direct measurements; it uses correlation curves to calculate emissions levels. However, the low fPM standard in the Rule makes developing this correlation curve - virtually impossible." PGEN Comments at 22 (citing PM CEMS Technical Memo at 3). Similarly, the QA/QC criterion for CEMS arc extremely difficult to meet at such low levels. ,See Commenr. of the ( USS Of '85 Regulaloiy Response Group on the PrOpoScil (ill F1171.101i ilti:ItirdOILS' Air Pollutants: Coal- and Oil-Tired Electric Ifuluy Steam Generating Units Review of the Residual Risk and Technology Review, Docket No. EPA-HQ-OAR-2018- 0794-5989, at 16 (June 28, 2024) [hereinafter "Class of '85 Comments"]. In fact, at the time of the proposed MATS RTR, no commercially available PM CEMS would have been able to meet the tight confidence and tolerance intervals associated with the low proposed fPM standard. PGEN 3 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000163-00003 SC_EVERSPLIT0005937