Document Rj14Nd1Eq2ZxDL8XVbmoxDQOn

On March 12, 2025, EPA released a fact sheet regarding the MATS RTR as part of "Powering the Great American Comeback" (the Fact Sheet). The Fact Sheet recognizes the regulatory uncertainty for coal plants, including those in North Dakota. It offers the opportunity for "any source interested in a Presidential exemption, should provide their recommendations to EPA by March 31, 2025." This letter responds to EPA's invitation. EPA also announced on its website the availability of exemptions and directed requests for exemption be submitted by March 31." Accordingly, Otter Tail and the Co-owners seek a two-year exemption from the MA I'S RTR standards for Coyote Station, due to technological unavailability related to the lignite mercury standard, the PM CEMS requirements, and the time and cost necessary to meet the requirements. Section III explains that the technology required to meet the Rule's new lignite mercury standard is not available, and Section IV explains that PM CEMS are likewise unavailable. Section V finds that it is in the national security interest to issue an exemption from compliance with the MATS RTR for Coyote Station. III. Technology' to Implement the MATS RTR Nlereury Standard lias Not Been Proven to Be Available The new lignite mercury limit has not been shown to be achievable with current, available control technolo2y.12 Likewise, the technology has not been shown to he available at Coyote Station on the long-term basis required by the MATS RTR. Coyote Station utilizes halogenated Powdered Activated Carbon (PAC) sorbcnt to control mercury via PAC injection. This is the same control technology EPA found under the Bidcn Administration should be able to achieve over 90% removal efficiency to meet the new mercury standard. However. the 2024 MATS RTR does not present any demonstrated evidence that the long-term mercury removal efficiency demanded by the Rule is possible. Instead, the Rule assumes that operators can simply add more PAC in their systems to achieve the emissions limitation. During the comment period on the proposed MA IS RTR, Otter Tail presented evidence to EPA to explain why this assumption is incorrect. As described in those comments, the mercury "removal curves flattens and there are diminishing returns in increasing sorbent injection rates."'' In other words, operators cannot simply "dial-up" the sorbents used to decrease mercury emissions to meet the new standard. This fact is further underscored by testing performed by one of our Co-owner's agents, Minnkota Power Cooperative. Minnkota's Milton R. Young Station purchased brominated PAC for the purpose of determining if that product could achieve improved mercury removal as compared to non-brominated PAC. The testing results at the Young Station Unit 1 demonstrate that the 11' https:,,www epa.gov 'systemli les"doeuments. 2025-03 Taet-sheet-reconsideration-of-mercurv-and-air-tox ics- standard s.pdf - https:'. www epa.c..ov stationary-sourecs-air-pol ean-air-act-section-112-presidential-exemption- information. 12 rs: Brief at 16-17,,Vorth Dakmu FP-1, i\o 24-1119, I)nc 2077742 (Oct 1, 2024) 13 Otter 1 ail Comments at 4. 4 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000194-00004 SC_EVERSPLIT0005967