Document OE50DjmDKGGLm0nxadk6o3omv

TALEN MONTANA Table 2: fPNI Emission Reductions by Potential fPM Standard fPM Emission Reduction Total of All Facilities-14 Colstrip-15 PotentialIPM Standard 0.015 lb/MNIBto 0.010 lb/NIMBto 0.006 lb/NIMBto 463 tons/yr 2074 tons/yr 6163 tons/yr Unit 3: 82.3 tons/yr Unit 4: 166.6 tons/yr Total: 248.9 tons/yr Unit 3: 442.1 tons/yr Unit 4: 528.3 tons/yr Total: 970.4 tons/yr Unit 3: 442.1 tons/yr Unit 4: 528.3 tons/yr Total: 970.4 tons/yr As reflected above, EPA associated nearly 47% of the total f-PM emission reduction for the proposed 0.010 lb/MMBtu fPM limit to Colstrip. However, that result relics on questionable assumptions. For instance, to achieve the 0.015 lb/MMBtu fPM limit, EPA assumed that Colstrip would conduct maintenance of its venturi wet scrubbers. But maintenance alone (or any other optimization measures) will not further improve the performance of Colstrip's wet scrubbers, as they are already performing at maximum optimization, as discussed above in Section 11.A.4 Similarly, to achieve both the 0.010 lb/MMBtu and 0.006 lb/MMBtu fPM limits, EPA assumes that Colstrip will install a new FF that would "reduce[] baseline f-PM rates by 90% subject to a floor of 2.0E-03 lb/MMBtu."41 In taking the 99 percentile of the lowest quarter to describe the baseline fPM rate for each ECU, EPA assumes for Colstrip a baseline of 0.018 lb/MMBtu fPM for Unit 3 and 0.021 lb/MMBtu fPM for Unit 4.48 With a 90% reduction, this means that EPA is assuming that Unit 3 would achieve 0.0018 lb/MMBtu IPM (subject to the 0.0020 lb/MMBtu JPM floor caveat) and Unit 4 would achieve 0.0021 lb/MMBtu IPM with a FF. But such emission rates are significantly below either the proposed 0.010 lb/MMBtu fPM limit or the more stringent 0.006 lb/MMBtu fPM limit EPA is considering. Moreover, EPA has provided zero engineering justification for its assumption that any EGU could achieve such emission rates with FFs/baghouses, much less Colstrip's units with their unique configuration. S&I..'s technical reports in fact states that FF vendors would not be able to guarantee rates as low as EPA's 0.0020 lb/MMBtu fPM floor assumption. For instance, S&I, state that "[w]ith the usage of more expensive fiberglass bags with a PTFE [polytetrafluroethylenc] membrane coating, it is expected that 0.00375 lb/MMBtu of filterable PM emission could be achieved but would not he guaranteed hi vendors" and "i a Is such, a best-case scenario would be Table 6, id. at PI)F p. 1 1 ,Appendix I), id. at PI)F p 80 (total fPM emission reductions for Colstrip arc calculated by summing the annuali7ed costs for Units 3 and 4) See ; Table S. id at PI)F p. 1 0-1 2. See id at PI)F p. 10. 'W See id at PI)F p. 4; Appendix C. id at PI)F p. 46 15 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000307-00016 SC_EVERSPLIT0006112