Document QkGv4KJNJML6Lx0Bb1kV6oXw6

TALEN ENERGY NortiNestern EFI('P)Y - 11 - March 28, 2025 least in the near future. Hines Declaration "I 45-52; NorthWestern Comments 13-16 ("Transmission limitations on the ability to import power"). "Colstrip plays a critical voltage-maintenance function." I lines Declaration 1 65. Without Colstrip and its uninterrupted operation, there is a significant blackout risks which would affect businesses and "important infrastructure." M. U 66, 67. This is especially the case because North Western, as a regulated utility, made targeted capital investments improving grid reliability, which had not planned for the 2024 MATS Rule and its costs. NorthWestern Comments 21-22. The economic consequences of grid disruptions are severe and well-documented, and they pose a national security concern in and of. themselves. If Colstrip is forced to reduce or cease operations because it cannot timely comply with the 2024 MATS Rule, there would be an increased risk of the kinds of devastating disruptions that have recently hit California and Texas. Hines Declaration 52, 64 67. All these issues warrant heightened attention when considering military readiness. Colstrip powers the northwestern region generally, including the military bases located in the area. The State of Washington alone is home to nine known military bases. And Oregon, Montana, and Idaho collectively house seven more. Any risk to power disruption in and around these bases affect core national security issues. External sources confirm I glen Montana and NorthWestern's grid reliability concerns. The Western Power Pool projects that for July to August, the planning reserve margin falls below 10% for most of 2026 to 2029. The North American Electric Reliability Corporation (NERC) projects that reserve margins reach levels of 10% or below overall starting in 2031. NERC, 2024 Long Term Reliability Assessment 127 (Dec. 2024).7 Lastly, Colstrip is also vital to protecting "economic security" as expressed in the two Executive Orders discussed above. See 90 Fed. Reg. at 8433; 90 Fed. Reg. at 8353. Colstrip supports more than 3,000 jobs in the local economy, provides 5240.3 million in income for Montana households, and about $102.8 million in state tax revenue to Montana. Indeed, it has been calculated that Montana benefits in economic activity worth over S1 billion from Colstrip in the form of electricity costs and reliability, inter-region trade, and lower state government spending. Lcbsack Declaration 58 (including Attachment C);' 1-alen Montana Comments 6 7. Available at https: "\`````.ruirc.com paiRAPAiraReliability%20Assessmentsl.)4)20DL Rehabilityl.)4)20Assessment 2024.pdf. Lonerii20Terml.)4)2() The I.cbsack Declaration includes an "Attachment (7 which is a study of Colstrip's economic contributions prepared by Dr. Patrick M. Barkey. Ph.D. Sierra Club FOIA 2025-EPA-04883 ED_018388_00000306-00011 SC_EVERSPLIT0006095