Document 6Rbrv6G2jgRM1BydqpdON1qEd

USCA Case #24-1190 Document #2062093 Filed: 06/27/2024 Page 4 o 123 7. For this Declaration, I reiterate the primary points from the earlier comments and provide additional updated facts. I have also evaluated the changes from the Proposed MATS2 Rule to the final rule announced on April 25, 2024 and published in the Federal Register on May 7. 2024, "National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units Review of the Residual Risk and Technology Review" 89 Fcd. Reg. 38.508 (May 7. 2024) ("MATS2 Rule"). The MATS2 Rule is a complex regulation that NorthWestern continues to evaluate. 8. Nevertheless, there arc certain conclusions that can be drawn at present regarding the impacts of the MATS2 Rule on NorthWestern, its customers, and the rate paying citizens of Montana. My comments here focus principally on the implications of. the MATS2 Rule on the future of NorthWestern's ownership share in the Colstrip Steam Electric Station, located in Colstrip, Montana ("Colstrip") and thus the potential effects on our portfolio. Presently NorthWestern owns 222 MW and starting in 2026 it will acquire an additional 222 MW for a total of 444 MW of capacity in Colstrip Units 3 & 4. Colstrip Units 3 & 4 arc coal-fired electric generating units ("EGijs"), and other than small waste-coal units not relevant to the MATS2 Rule, the only coal-fired EGUs in North Western's Montana electric generation portfolio. 9. In this Declaration, I make the following points: a. NorthWestern has analyzed various potential closure dates for Colstrip through its public Integrated Resource Planning ("IRP") process. Prior to the finalization of the GHG Rule and MATS2 Rule, NorthWestern had planned for reliance on Colstrip through 2042. Finalization of the GIIG and MATS2 Rules creates two additional closure scenarios: July 8, 2027 (when compliance with the MATS2 Rule is required, unless the State grants a one year extension), and January 1, 3 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000310-00004 SC_EVERSPLIT0006259