Document NGn9mQmr7QM9dq5Qw064dMjkV

June 23, 2023 EPA-HG-OAR-2018-0794 Page 4 using an atomic absorption spectrometer. GVEA estimates that the capital cost would be $150,000. GVEA is also currently researching the cost of equipment necessary to process the Hg sorbent traps onsite to facilitate real-time response. GVEA estimates that the capital cost would be $80,000 and annual operating costs would be $10,000. 5. GVEA has reviewed the following documents prepared in response to the proposed MATS Rule amendment. In general, GVEA concurs with the issues and critiques of the proposed rulemaking action in these documents. a. Technical Comments on National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-fired Electric Utility Steam Generating Units Review of Residual Risk and Technology, prepared by J. Edward Cichanowicz, James Marchetti, and Michael C. Hein, for the National Rural Electric Cooperative Association, American Public Power Association, America's Power, Midwest Ozone Group, NAACO, National Mining Association, Power Generators Air Coalition, June 2, 2023. b. Technical Comments of EPA's Proposed Rule: Mercury and Air Toxics Standards Risks and Technology Review, prepared by Ralph L Roberson, P.E., RLR Consulting LLC, for NRECA, June 5, 2023. Specifically, GVEA agrees with the following concerns addressed in these documents: a. The database used for determining the new filterable particulate matter standard for existing low rank virgin coal coal-fired units is inadequate. The database does not consider variations in operating profiles, coal composition, seasonal load, and process conditions. The database also does not consider the difference between source test or CEMS results. b. EPA does not recognize other differences in the composition of lignite and subbituminous coals when proposing to revise the mercury (Hg) limit standard for existing low rank virgin coal coal-tired units. These differences include the content of mercury and its variability, the content of sulfur, and the alkalinity of inorganic matter. c. No legal basis exists for EPA's proposed elimination of the quarterly stack testing option for demonstrating compliance with the filterable PM emission standard. d. The proposed mercury (Hg) standard of 1.2 lb/TBtu may not be achievable for GVEA's units which burn low rank coal. GVEA has measured significant variation in Hg content of the coal, ranging between 0.000mg/kg and 0.417mg/kg. e. The proposed fPM emission limit of 0.010 lb/MMBtu should be reconsidered. In compliance with a 2012 Consent Decree GVEA operates PM CEMS on both Healy EGU's with an emission limit of 0.020 lb/MMBtu. GVEA's PM emissions are well below the proposed limit, however GVEA has found it difficult to achieve successful PS-11 correlations and successful triennial RCA's using the 0.020 lb/MMBtu limit in EPA's PS-11 calculation spreadsheet. None of GVEA's current correlations would have acceptable models with the proposed emission limit and Sierra Club FOIA 2025-EPA-04883 ED_018388_00000057-00013 SC_EVERSPLIT0005613