Document 5kJgKyk7woQ5qVm2qY8LkaBw5

Minnkota Power Cooperative, Inc Milton R Young Station Unit 2 A14559 010 Rev No Final June 23. 2023 Therefore, additional testing would be required to establish if it is feasible to achieve a 1.2 Ib/TBtu Hg emission rate with sufficient operating margin on a lignite unit and if so, develop an overall Hg compliance approach that likely would consist of a suite of control approaches to achieve this rate on MRY Unit 2. In summary, additional testing would include, but not be limited to, the following: Hg speciation data upstream of the ESP, upstream of the WFGD and at the stack (with no controls, current operation and maximum capacity of existing Hg control equipment, and test conditions for other listed items) Performance with increased concentrations of current fuel additive system, including additional injection locations, as well as potentially testing other halogen -based fuel additives than what is currently used. Performance with halogenated PAC, considering capabilities of existing Hg control equipment and increased injection rates (while also consid ering other test conditions for other listed items). Note that due to the limitations of the existing equipment, a separate test skid will be required to facilitate this testing campaign. If WFGD re-emission is determined to be occurring based on Hg speciition upstream and downstream of the WFGD, the performance of a re-emission additive can also be tested. As mentioned previously, PAC suppliers have indicated that testing would be required in order to obtain any guaranteed performance. Therefore, recommended consumption and/or injection rates to determine the modifications and/or new systems required are not available at this time to develop the subsequent cost of the suite of Hg controls neededto achieve adequate operating margin below a 1.2 lb/TBtu Hg Emission limit on MRY Unit 2. Particulate & Mercury Control Technology Evaluation & Risk Assessment for Proposed MATS Rule Sierra Club FOIA 2025-EPA-04883 I_Lirliciv 12 ED_018388_00000327-00042 SC_EVERSPLIT0006351