Document 8R2zm5Q9v0Ek3oxrRQ5VQjejm

USSOA02see##241-1280 Ciaoouratatit206636@3 FFfildc1006/2Y22024 PIgge456 of @28 32. Dollars spent on design, permitting, engineering, and other studies cannot be refunded once they are spent. The costs associated with implementing 40 percent natural gas co-firing or installing CCS to achieve 90 percent capture of CO, so that Colstrip can operate beyond 2032 are massive. Colstrip would need to spend significant time, resources, and investments to not only implement the technologies, but also to construct supporting infrastructure. When added to the costs associated with complying with the proposed requirements in other rulernakings that impact Colstrip, such as the 2024 MATS Rule, the investments required for Colstrip to operate beyond 2032 would cost many hundreds of millions of dollars. Such costs would likely render Colstrip financially unviable, given Colstrip's uncertain but limited future. Premature Retirement is the Only Option for Colstrip 33. Given that the CCS and co-firing compliance options are nearly impossible to execute successfully by the Rule's deadlines, and given that the costs of these compliance options would be prohibitively expensive to undertake, especially in light of future uncertainty, the Rule requires retiring Colstrip Units 3 and 4 by January 1, 2032. As discussed above, moreover, the interplay between the Rule and the MATS Rule means that Colstrip would likely retire by July 2027. 34. This litigation is likely to take a minimum of 2 to 3 years. If the Rule is not stayed, Talen will have suffered irreparable harm by the time the legality of the rule is determined. Before we know whether the rule will be struck down, Talen would have to elect -- within a year at the most -- to shut down Colstrip, and it would have to actually shut down the plant by mid-2027. 10 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000309-00060 SC_EVERSPLIT0006223