**Summary of Process to Identify the Appropriate Site**
**- Specific Technology where Preapproved BTA**  **is Infeasible** 
F or the small number facilities where the preferred BTA is infeasible given site

- specific factors, 1 EPA should establish a rigorous process for state environmental regulators and facilities to identify appropriate alternative technologies considering the expected impingement mortality reduction, including avoidance of impingement, and cost

- benefit analyses. Append ix A highlights the types of plants that could have circumstances where the preapproved BTA will be infeasible because of site constraints or the preapproved BTA would have very substantial impediments to their effectiveness or could not be installed at ex isting cooling water intake structures at a reasonable cost. The following outlines the process companies and permitting directors would undertake to identify the appropriate site

- specific technology to ensure that the rule results in a significant nationa l reduction in impingement mortality with important environmental and ecological benefits throughout the U.S. Comparable Discussion for Impingement Mortality If the preapproved BTA2 is technically infeasible based on site

- specific considerations , or if a company identifies that a more cost

- effective technology will achieve comparable performance to preapproved BTA, the company, in coordination with the permitting director, should engage in a process to select the comparable BTA technology(ies) required fo r the site considering expected impingement mortality reduction, including avoidance of impingement, and considering social costs compared to social benefits. Th is analysis must reflect the Director’s determination of the maximum reduction in impingement mortality warranted after consideration of all factors relevant for determining BTA for the facility.
For each site

-specific BTA determination, t he Director must provide a written explanation of the proposed BTA determination for the proposed permit. The written explanation must describe why the Director has rejected any impingement mortality control technologies or measures that are better

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1 As has been demonstrated during the public comment process, a small but important number of plants will have circumstances where the preapproved BTA will be infeasible because of site constraints or the preapproved BTA technology would have very substanti al impediments to effectiveness or could not be installed at existing cooling water intake structures at a reasonable cost. As detailed in Appendix A, e xamples of these circumstances include: 1) long return and unfavorable receiving water environment; 2) s ubstantial debris

- loading and NPDES prohibition on return of debris; 3) impacts due to cake and frazzle ice on screens, in trough, at point of return; 4) screen house and other infrastructure constraints on retrofit; and 5) redundancy with existing effecti ve measures. 2 Pre

- approved BTA includes: modified traveling screens, such as Ristroph screens or equivalent modified traveling screens, with a fish return system ; approach velocity of 0.5 feet/second (fps), measured at the first point of entry to the cool ing water intake system; pre - existing offshore velocity caps; or existing closed

- cycle cooling, including cooling towers or cooling ponds that were not themselves considered to be waters of the U.S. at the time that they were built. As explained in our co mments, EPA’s proposed definition of a “closed

- cycle recirculating system” at 40 CFR 125.92 is unnecessarily restrictive. The proposed definition indicates that closed

- cycle cooling should not “rely upon continuous intake flows of water”. Our recommended r evisions to the definition included in our comments intends to preclude one

-time passage of water, but recognizes that it is common practice for cooling towers and cooling ponds to receive makeup water on a continuous or semi

- continuous basis to offset eva poration, drift, and blowdown.performing than the pre - approved BTA, and must reflect consideration of all reasonable attempts to

mitigate any a dverse impacts of otherwise available better performing impingement technologies. The Director may reject an otherwise available technology as BTA for impingement mortality if the social costs of compliance are not justified by the social benefits or if t here are adverse impacts that cannot be mitigated and that the Director deems to be unacceptable. If all technologies considered have social costs not justified by the social benefit s, or have unacceptable adverse impacts that cannot be mitigated, the Director may determine that no additional control requirements are necessary beyond what the facility is already doing. At a minimum, the proposed determination in the statement of basis must be based on consideration of the following factors: (1) Numbers and types of organisms impinge d , considering technologies that reduce the number of fish impinged ; (2) I mpingement mortality impacts on the waterbody, considering seasonal dynamics ; (3) Quantified and qualitative social benefits and social costs of available impingemen t technologies, including ecological benefits and benefits to any threatened or endangered species; (4) Impacts on the reliability of energy delivery within the immediate area; (5) Impact of changes in particulate emissions or other pollutants associated with imp ingement technologies; (6) Land and space availability inasmuch as it relates to the feasibility of impingement technology; (7) Impacts on water consumption ; (8) Location and design of current intake; (9) Remaining useful plant life; and (10) Facility size. In identifying the site

- specific BTA technology, the facility and permitting director should consider any applicable examples included in a database EPA should establish to illustrate the expected performance of BTA technologies at specific sites. These examples would be based on a robust data set and reflect different situations that will affect impingement and impingement mortality such as different water bodies, fragile species, facility sizes, and seasonal dynamics. The expected performance should be based on both fish mortality and biomass, and account for actions that prevent fish impingement in the first place

. This database and review will facilitate permitting authorities’ identification and assessment of alte rnatives to the preapproved BTA technologies. These examples would not establish a national precedent that would be applicable to all facilities.**Appendix A Examples of Situations Where**  **Preapproved BTA is Not Technically Feasible**  A small but important number of plants will have circumstances where the preapproved BTA will be infeasible because the preapproved BTA technology would have very substantial impediments to their effectiveness or could not be installed at existing cooling water intake structures at a reasonable cost. Examples of these circumst ances include:

1. Long return and unfavorable receiving water environment

– Existing facilities are often located in industrial areas at some distance from the source of cooling water, and in many cases, cooling water canals have been constructed for both th e intake and discharge flows to access the source and receiving waterbodies (which are not always the same). These features allow the plants to be constructed further away from the source waterbody, but the associated distances create a challenge to effective return of impinged organisms to their natural habitat. Often, the closest potential return location has substantially different characteristics (e.g., depth, currents, and water quality) such that returned organisms may be exposed to additional stres s, predation, or other factors affecting their survival. Topographic extremes add to this issue, both in the case of flat terrain with long runs to the waterbody as well in more rugged terrain where straight runs to the waterbody may not be feasible. Suc h systems result in long residence times within the return system with increased potential for temperature and handling stresses. In many cases, nearby locations for fish return are affected by the thermal loading of the plant’s discharge, resulting in ad ditional stress on the organisms once they are returned to the receiving water. In other cases, favorable locations for fish return are subject to heavy port activities and shipping traffic, precluding access to the waterbody by a fish return and likely a dversely affecting the survival of returned fish. NextEra Energy’s Port Everglades plant exhibits all three of these potential concerns due to the length to the closest access to the source water (approximately one - half mile), which is used as a major har bor for commercial shipping and cruise ships. Additionally, Constellation Energy’s Gould Street facility has traveling screens installed but no fish return system. A fish return system is not feasible given the location in a cove off of the Patapsco Rive r. The facility is located between a Tyco cable

- laying ship facility and a marina. Given the small size of the plant’s property and the surrounding uses in the area, there is no place to locate a fish return away from the intake and thereby avoid re

- impi ngement. Because the waterbody has significant boat traffic, it is also not possible to install a fish return pipe extending beyond the cove. Another example of an ineffective and infeasible fish return is NextEra Energy’s Seabrook plant, which is loca ted approximately 1.5 miles inland from a set of barrier islands and approximately one mile from the estuary. The plant receives its cooling water from a velocity cap located a further 1.3 miles offshore. Return of the (very small number of) impinged fis h to the estuary will result in mortality due to the inappropriateness of this habitat compared with the deep offshore environment. Additionally, construction of a fish return to the ocean is precluded by the extremely long distance, which includes appro ximately one mile of wetlands, a half

- mile of openwater estuary, and the barrier islands. In fact, the existing subsea and underground tunnel for

intake and cooling water was designed to avoid impacts to these sensitive environments and the near- shore se a bottom. The situation at NextEra Energy’s St. Lucie facility is very similar. Finally, widely fluctuating water levels in rivers (either associated with locks and dams or normal hydrological variation) or tidal systems also complicate design of an effe ctive fish return system. For example, at NextEra’s Wyman plant on the coast of Maine, the tidal variation is between 10 and 12 feet.

2. Substantial debris loading and NPDES prohibition on return of debris

– Many of NextEra Energy’s regulated plants in Fl orida experience significant debris loading from floating macroalgae, uprooted seagrass, and jellyfish that result in substantial loading of naturally

- occurring material/debris on the traveling screens. The discharge permits require that aquatic organism s be returned to their natural habitat but prohibits the return of any other material collected from the traveling screens to the receiving waters. We are also aware of similar prohibitions in other states and cases where the mass of man

- made debris excee ds the mass of fish by approximately 100

-fold. We are concerned that these naturally

- occurring events of seagrass and other material loading on the screens will result in compliance issues, primarily: 1) achieving the impingement mortality performance goa ls due to physical stress from the high debris loads on the organisms during impingement on the screens and during efforts to separate them from the debris; and 2) inability to comply with the prohibition on returning debris to the receiving water body due to the requirement to return aquatic organisms. Similarly, we are concerned that organisms that are attached or otherwise difficult to remove from the debris during these critical events would be included in the mortality losses, further contributing to potential non

compliance with the impingement mortality performance goals. Thus, the rule should include provisions for the impacts from these events similar to the Phase II rule’s recognition that the permitting director had the discretion to consider u nique and exceptional events in evaluating compliance with that rule’s performance goals.

3. Impacts due to cake and frazzle ice: on screens, in trough, at point of return

– Many existing plants have operational measures to limit the impact of ice during c old weather. In some cases, warm water is circulated out to the front of the intake area to avoid ice buildup on bar racks and screens. While necessary to maintain normal plant operations, these measures will likely present additional obstacles for fish that are impinged and returned to the source water body at or near ambient temperatures. Under severe wintertime conditions, ice will form in the return troughs and at the point of return to the waterbody. Such conditions would be encountered at NextEra Energy’s Point Beach plant in Wisconsin as well as several other plants located in northern climates.

4. Screen house and other infrastructure constraints on retrofit

– The intakes and traveling screens at many existing plants were designed primarily for the purpose of debris removal and were sized to preclude objects that would clog the condenser tubes. The majority of traditionaltraveling screens are housed in fiberglass enclosures installed to provide a safety enclosure to

protect workers from the equipm ent as well as to protect the equipment from the elements. Facilities in more northerly climates have screen houses that shelter these enclosures. Many plants will face substantial space restrictions within the intake bays and the screen houses for retro fitting fish

-friendly screens, additional pressure washes, fish return troughs, etc. Similarly, several existing plants are highly constrained by existing infrastructure both on the plant site and in the environs of the plant on the way to the source wate r. These have the potential to greatly complicate the construction of the return and increase the stress on the returned fish. Such is the case for NextEra Energy’s Port Everglades plant, which has a major thoroughfare between it and the closest location for a fish return.

5. Redundancy with existing effective measures

– A broad requirement for the installation of fish

friendly traveling screens and fish return systems provides an unnecessary level of redundancy with little additional benefit at some faci lities. Examples include plants designed with offshore intakes that include velocity caps and acoustic deterrents (e.g., NextEra Energy’s St. Lucie, Seabrook, and Point Beach plants), where the combined benefits of offshore locations and use of velocity c aps (St. Lucie and Seabrook) and the use of innovative offshore intake designs and deterrence systems (Point Beach) substantially reduce impingement rates. NextEra Energy’s Duane Arnold plant is already equipped with cooling towers that should be consider ed compliant with the proposed impingement mortality and entrainment mortality performance standards. Requirements for additional technologies are not cost

- effective and do not provide a significant benefit to warrant their costs.