Document pe4BrrKdjm9KXwDQxo5Bp4nxd

electric generating facilities by the MATS MR, EPA has announced the potential availability of such exemptions and asked that requests for exemptions be submitted by March 31. See https://www. epa.govistationary-sources-air-pollutioniclean-air-act-section-112-presidential-exemptioninformation. Consistent with that announcement, and for the reasons set forth below, Dyne2y Midwest Generation, LLC requests a 2-year exemption for Baldwin Units 1 & 2 from the fPM standard and from the requirement to install and use PM CEMS. Importantly, EPA has been very clear that the fPM standard and the CEMS requirement are completely integrated, such that any exemption must cover both requirements in the Rule. Specifically, EPA explained "that a fPM standard of 0.010 lh/MMBtu . .. is the lowest f-PM emission limit possible at this time with use of PM CEMS." 89 Fed. Reg. at 38,534. And EPA identified the revised fPM standard and the PM CEMS requirement as a combined "two-pronged approach," stating that "requiring PM CEMS in addition to a lower fPM limit . . . is the most stringent option that balances the benefits of using PM CEMS with the emission reductions associated with the tightened fPM emission standard." Id. at 38,530. In other words, EPA's effort "to implement" its revised standard depends equally on both the more stringent numeric standard for fPM and on the obligation to install new monitoring equipment. Section I explains that the technology required to implement the Rule's revised fPM standard is "not available" on a continuous basis, and Section II explains that CEMS are likewise unavailable. Given the interdependence of these requirements, however, the unavailability of technology as to either component makes "implementation" of the standard likewise unavailable for the other. Section III concludes that it is in the national security interest to issue an exemption from compliance with the MATS RTR. I. The Particulate Control Technology Required to Implement the Rule's fPNI Standard is Not Available Baldwin currently utilizes an electrostatic precipitator ("ESP") and baghousc for particulate control. Despite these controls, there are technological and operational limits at Baldwin that make it difficult and expensive to meet the more stringent fPM standard on a continuous basis under all operating conditions. EPA based its decision to lower the fPM standard on data from only a select few units. See Pet'rs' Brief at 65-68, North Dakota %. EVA. No. 24-1119, Doc. 2077742 (Oct. 1, 2024). In doing so, EPA did not take into consideration the operational challenges associated with meeting this low limit on a continuous basis. During peak conditions, it is difficult to push ESPs to perform at levels beyond their original design or performance guarantees while trying to maintain grid reliability. The units may be unable to perform off-power rapping or maintenance and cleaning during those times. Operational factors such as cleaning frequency, operational duration, and maintenance frequency may also impact the performance of ESPs. Even with a ba2house--which can provide additional PM control--the more stringent limitation will be challenging because ba2houses are not designed to vary control rates. 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 filter change-out frequency may impact the performance of the baghousc and a facility's ability to comply with the revised limit under all operating conditions. These concerns are exacerbated by the companion requirement to measure compliance using monitors that have not been demonstrated to be reliable. 2 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000174-00002 SC_EVERSPLIT0005953