Document 7M8xm4eKbz0a26LzLddbjX79o

U.SIDA.ACOaet#441.1280 Dtdoturreah##00626@3 Fikidc100t22722944 PFIgge448 of g28 significant concern. WECC reports that current utility resource plans in the western interconnect "are not sufficient to meet future demand over each of the next 10 years," and that "starting in 2026, the number and magnitude of demand-at-risk hours increase by orders of magnitude."' a. In statements made in comments on both the proposed MATS rule and the proposed version of this Rule in 2023, Northwestern Energy indicated that there will not be sufficient replacement power on the grid by 2027 if Colstrip must retire. 40. Colstrip Units 3 and 4 generated approximately 41 percent of the electricity generated in Montana in 2022 and represented 23 percent of total installed generating capacity. A decision to prematurely retire Colstrip, an important baseload generator serving at least five states, would cause significant reliability concerns. These concerns would apply well into the rest of the decade, even if the Rule is not stayed and is struck down by the courts at around the same time the plant would shut down. Dated: May 24, 2024 1; <-4 ,e; ; - Dale E. Lebsack, Jr. Western Electricity Coordinating Council, 2023 Western Assessment of Resource Adequacy (Nov. 2023), available al Imps: www. -i.or2 Administrative 2023'! .JIWestern'' '0Assessment' ri2Oot'dinResourcili (1Adcquacv.hdf (Attachment A). 12 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000309-00062 SC_EVERSPLIT0006225