December 30, 2011

MEMORANDUM TO: Existing Facility Rule Doc FROM: Mary T. Smith, Director

Engineering and Analysis Div RE: Changes to Draft Proposed Rule During Interagency Review The following list contains the most significant changes to EPA's draft proposed rule during interagency review. For a more exhaustive list, see the redline/strike out PDF file in the public docket for this rulemaking. All page numbers below refer to the page numbers in the PDF file in the public docket. 1. Narrowed the definition of new unit, EPA draft proposed rule would have required all new units to incorporate closed—cyle cooling or its equivalent. During interagency review the definition of new unit was significantly narrowed to include only newly built units added to increase capacity at the facility and does not include modifications necessary as a result of emergency repairs, any rebuilt, repowered or replacement unit, including any units where the generation capacity of the new unit is equal to or greater than the unit it replaces. Because of this definitional change a number of conforming changes in the preamble were necessary, including the justification for this approach. 2. Addition of Option Four that excludes facilities that withdraw less than 50 MGD from national rule coverage. The principal discussion of this option appears on pages 135 and 136 but conforming changes are made throughout the preamble. 3. Inserted "nor does it require that EPA develop nationally applicable performance requirements through rule making" on page 20. 4. Deleted discussion of European approach to cooling water intakes structures on page 48. S. Deleted/rewrote other utility rule discussion on page 48 and 49 of docket PDF file. 6. Deleted "EPA interprets 40 CFR 122.2 to give permitting authorities the discretion to regulate cooling ponds as "waters of the United States" where cooling ponds meet the definition of "waters of the United States." " 7. Inserted E.O. 13563 paragraph on page 95. 8. Deletion/insertion of language on bottom of page 96 and top of page 97. 9. Insert on page 107 regarding consumption water use of wet closed-cycle cooling. 10. Insert on energy efficiency at top of page 108. 11. Insert on annual limits derivation, variability and adaptive management on pages 121-123.12. Insertion of site-specific entrainment control determination at the bottom of page 129 and the top

of page 130. 13. Changes to option selection discussion on pages 135-150. 14. On page 150, inserted "These increased air emissions have human health, welfare, and global climate change impacts which must be considered in the cost of closed-cycle cooling)," as well as the insert on page 152 "of various pollutants, including particulates, sulfur dioxide, nitrogen oxides, mercury, and greenhouse gases, among others." 15. Changes on pages 153-155. 16. Changes on pages 158-169 related to site-specific entrainment determinations and their costs. 17. Insertions regarding additional costs on pages 171 and 172. 18. Insert on page 261 regarding additional cost of site-specific entrainment controls. 19. Changes to thermal impacts discussion on pages 283-285. 20. Insertion of peer review discussion on page 311. 21. Insertion regarding monitoring requirement on pages 322 and 323. 22, Insertion of language on cost/benefits evaluation on top of pages 337, and 341-2. 23. Changes to cost/benefit balancing by permit Director on page 344. 24. Insertion of request for comments on waterbody type and capacity utilization rate on pages 383 and 384. 25. Insertion of request for comments on costs of controls to eliminate entrapment on page 387. 26. Insertion of items 25 and 26 on page 389. 27. Insertion of (12)(viii) on page 408. 28. Deletion of the following sentence on page 428: "Closed cycle cooling is the best performing technology for reducing entrainment mortality, but it may or may not be the STA for individual facilities in light of site-specific considerations." A similar deletion was also made on page 449. 29. Changes on pages 431 and 450 30. Insertion of water consumption impacts on page 451.