Document o92rBG5w9oEg82rX5jGDD78Z3

NorthWestern Energy Delivering a Bright Future RTR, but rathcr only a change in policy regarding the same practices, standards, and control technologies. Basing revised standards simply on a policy reversal is contrary to thc text and structure of Section 112(d)(6), especially when coupled with the tight statutory compliance deadlines provided in Section 112. The Clean Air Act envisions that both EPA and the regulated community would be able to monitor evolving trends in emission control technologies and practices, such that regulated could sec and plan for potential upgrades that might be needed on thc horizon. But when LTA reverses course based on policy, not technological changes, regulated entities do not have similar advance notice when planning capital programs. This is contrary to thc statute. The Proposed Rule's statutory deficiencies are compounded by its proxy-on-proxy structure, where PM (a pollutant independently regulated under the NAAQS program) is used as a stand-in for HAPS. NorthWestern understands thc technical rationale for focusing on PM rather than attempting to !measure HAI'S directly, but the indirectness of thc regulation is problematic given the history of the Rule. Moreover, it will not be lost on a reviewing court that the Proposed Rulc is a transparent attempt to indirectly regulate greenhouse gas emissions in the immediate wake of West Virginia '. EPA, 142 S.Ct. 2857 (2022). For that reason, and because of its severe impacts to Montana and the reliability of the Western Interconnection, there is a significant likelihood that a court will subject the Rule to scrutiny under the Major Questions Doctrine. It is doubtful that EPA's departures from thc text and purposes of Section 1 12(d)(6) would survive such scrutiny. Independently of statutory and constitutional infirmities, thc Proposed Rule is also arbitrary and capricious under the Administrative Procedure Act. In addition to the reasons articulated by Talcn, the Proposed Rule and 2023 RTR takes the saine practices, standards, and control technologies as were examined in the 2020 RTR, and reaches a polar opposite conclusion. This is textbook arbitrariness. At a minimum, thc fact that EPA has reversed course so completely in such a short timcframc likely deprives EPA of any judicial deference it might otherwise have enjoyed. Given the unprecedented methods deployed in the Proposed Rulc to determine that thc Rulc would result in positive nct benefits, thcrc is a significant likelihood that the Proposed Rulc, if finalized, would be invalidated under the APA. 23 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000308- 00024 SC_EVERSPLIT0006161