Document dYOJ8j0124nd0QaMoq71pyw1e

r TALEN ell MONTANA First, the evaluation summarized in the Technical Memo excludes units that have shut down, will shut down, or will no longer burn coal/oil by December 31, 2028, or reported data in lbs/MWh.2' By failing to include units that will shut down or no longer burn coal/oil by December 31, 2028, EPA is not appropriately accounting for units that are likely emitting f-PM at levels closer to the current standard than the more stringent proposed f-PM limit. EPA should have accounted for such units given that affected EGUs will have up to three years after the effective date of the final rule to demonstrate compliance with the revised limit, and some of the excluded units may not have retirees or ceased burning coal or oil by the compliance cicadlinc.21 These units should be included when evaluating what fi'M levels current technologies arc capable of. achieving. If the final rule is issued before December 31, 2025, or if the announced retirements are delayed, these excluded units might become subject to a tighter standard that they cannot meet without large capital outlays to install PM control technology despite near-term projected fuel switches or retirement dates that would render such investments not cost-effective. Units that are retiring in the near-term and cannot meet the fPM limit without the installation of controls could be forced to shut down early, which could destabilize electric reliability in their service areas and could have long-lasting effects. Significant dollars would need to be spent to restart certain generating facilities if it is later determined that the decision to shut down early was detrimental to reliable grid operations. A compliance date based on three years after the final rule's effective date is inconsistent with other recent EPA rulemakings, which recognize that significant investments in emissions controls should not be required for EGUs that will retire in the near-term. Second, the evaluation is based on selected quarterly data from 2017, 2019, and 2021.2' 'Ile Agency fails to explain how and why it selected the specific quarterly data for those years for its evaluation when EPA has all quarterly tests and PM CEMS for the entire fleet since the effective date of the original MATS rule.' The Agency also fails to explain why it used a single quarter of data to present the unit's "baseline" and why "it ]he 99th percentile of the lowest quarter was chosen to describe the baseline fl'M rate for each EGU."3" This results in a questionable ciataset comprised of an extremely small industry sample size and where a single data point is narrowed down for each ECU. For example, for Colstrip, EPA utilized a baseline of 0.018 lbiMMBtu fPM for Unit 3 and 0.021 lbiMMBtu fPM for Unit These numbers do not reflect what is consistently achievable for Colstrip, as Colstrip has already optimized its existing controls to the greatest extent Sc'c' Technical Memo at PIE p. 2. 88 Fed. Reg. at 24,868, fn. 20. EPA excluded units that have announced that they will shut down by the end of 2028 based on the National Electric Energy Data System ("NEEDS") database, but such retirement plans arc not legally binding and thus such units should iu be excluded from the Agency's evaluation 'Technical Mcmo at p 2 ("Quarterly data from 2017 (variable quarters) and 2019 (quarters three and occasionally four) were first reviewed because data for all affected EGUs subject to numeric emissions limits had been previously extracted from C1-1)R I In addition, the EPA obtained first and third quarter data for calendar year 2021 for a subset of 1-.GUs with larger fi'M rates (generally greater than 1 0E-02 lb" M Mlitu for either 2017 or 2019) ") ' 11- he fact that this information had previously been extracted from C1-.1)R I is no explanation at all. See id. "Fcchnical Memo at p. 4. (emphasis added) 3 See id at p. 4; Appendix id at p. 46 10 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000307-00011 SC_EVERSPLIT0006107