CP - nn Page 1

CP-nn / Best Technology Available (BTA) for Cooling Water 

Intake Structures 

New York State Department of Environmental Conservation 

DEC Policy 

Issuing Authority: Alexander B. Grannis, Commissioner

Date Issued: Latest Date Revised: March 4, 2010

I. Summary: 

This policy prescribes the reductions in impingement mortality and entrainment 

required to minimize the adverse environmental impact caused by industrial facilities 

having a cooling water intake structure (CWIS) in connection with a point source thermal 

discharge. Water withdrawals from surface waterbodies through a CWIS cause injury 

and mortality to fish and other aquatic organisms through impingement at the intake 

and/or entrainment through the cooling system. Through this policy, the Department 

establishes closed-cycle cooling or its equivalent as the performance goal for the best 

technology available (BTA) to minimize adverse environmental impact pursuant to 

Section 704.5 of 6 NYCRR, Section 316(b) of the Clean Water Act, 40 C.F.R. Part 125 

subpart I, 40 C.F.R. Part 125.90(b), and 40 C.F.R. Part 125 subpart N in State Pollutant 

Discharge Elimination System (SPDES) permits. 

II. Applicability: 

This policy applies to all existing and proposed industrial facilities designed to 

withdraw twenty (20) million gallon per day (MGD) or more of contact or non-contact 

cooling water from the waters of New York State and that are subject to the requirements 

of Section 704.5 of 6 NYCRR. Existing and proposed industrial facilities subject to the 

requirements of 6 NYCRR § 704.5, that are designed to use less than 20 MGD of contact 

or non-contact cooling water will continue to be subject to the requirements of 6 NYCRR 

§ 704.5 and CWA § 316(b) or another subpart of 40 C.F.R. Part 125, as determined by 

the Department on a case-by-case, site-specific, best professional judgment (BPJ) basis. 

III. Policy: 

Through the general powers and duties of the Commissioner and the Department 

of Environmental Conservation [ECL Articles 1 and 3] to conserve and protect the 

natural resources of the state and to minimize adverse impact to the environment, the 

Commissioner hereby establishes the following performance goals to minimize adverse 

environmental impact from a CWIS: 

1. Dry closed-cycle cooling as the performance goal for all new industrial 

facilities sited in the marine and coastal district (ECL § 13-0103) and along the 

Hudson River up to the Federal Dam in Troy; 
CP - nn Page 2

2. Wet closed-cycle cooling as the minimum performance goal for all new 

industrial facilities located along all waters other than those covered by No. 1; 

3. Wet closed-cycle cooling or its equivalent as the minimum performance goal 

for existing industrial facilities that operate a CWIS in connection with a point 

source thermal discharge; and 

4. Wet closed-cycle cooling as the minimum performance goal for all repowered 

industrial facilities that operate a CWIS in connection with a point source 

thermal discharge. 

Furthermore, for an existing industrial facility where the Department determines 

that wet closed-cycle cooling is not an available technology, this policy establishes a 

performance goal of at least 90 percent or greater reduction in both entrainment and 

impingement mortality from that which would be achieved by a wet closed-cycle cooling 

system at that facility. Any existing industrial facility meeting these performance goals 

will be deemed in compliance with the requirements of 6 NYCRR § 704.5 and CWA § 

316(b) to implement BTA for minimizing adverse environmental impact related to the 

operation of cooling water intake structures. 

Definitions:

Adverse environmental impact – the fish killed or injured through entrainment and 

impingement by the operation of cooling water intake structures. The “adverse 

environmental impact” that must be minimized by the BTA standard of 6 NYCRR §704.5 

relates only to aquatic resources. 

Available –technically feasible with costs not wholly disproportionate to the benefits. 

Best Technology Available (BTA) – technology based standard authorized under CWA 

Section 316(b), 40 C.F.R. Part 125, subpart I; 40 C.F.R. Part 125.90(b); and 40 C.F.R. 

Part 125, subpart N and 6 NYCRR Part 704.5 as the most effective technology, process 

or operational method for minimizing adverse environmental impact from a CWIS. 

Calculation baseline – an estimate of impingement mortality and entrainment that would 

occur at a facility CWIS assuming that: the cooling water system has been designed as a 

once-through system; the opening of the cooling water intake structure is located at, and 

the face of the standard 3/8-inch mesh conventional traveling screen is oriented parallel 

to, the shoreline near the surface of the source waterbody and is operated at the full rated 

capacity 24 hours a day, 365 days a year. This is the baseline of adverse environmental 

impact to be used in estimating reductions in impingement mortality and entrainment 

resulting from operating a closed-cycle cooling system. 

Cooling water - the water used for contact or non-contact cooling, including water used 

for equipment cooling, evaporative cooling tower makeup, and dilution of effluent heat 

content. The intended use of the cooling water is to absorb waste heat rejected from the 

process or processes used, or from auxiliary operations on the facility's premises [6 

NYCRR § 700.1(a)(11)]. 

Cooling water intake structure (CWIS) - the total physical structure and any associated 

constructed waterways used to withdraw cooling water from waters of New York State. 
CP - nn Page 3

The cooling water intake structure extends from the point at which water is withdrawn 

from the waters of the State up to, and including the intake pumps [6 NYCRR § 

700.1(a)(12)]. 

Dry closed-cycle cooling - cooling system that uses air flow, rather than the evaporation 

of water, to remove heat from the power station in order to reduce or eliminate the 

consumptive use of surface waters. 

Entrainment – the incorporation of all life stages of fish with intake water flow entering 

and passing through a cooling water intake structure and into a cooling water system. It 

is assumed that entrainment results in 100 percent mortality of the entrained organisms. 

Equivalent to –providing a reduction in adverse environmental impact within a ten (10) 

percent margin of error of that which is attainable with the use of wet closed-cycle 

cooling. 

Feasible – capable of being done; able to be installed and function efficiently within the 

operating constraints of the facility. 

Impingement mortality – the death of all life stages of fish as a result of being 

entrapped on the outer part of a cooling water intake structure or against a screening 

device during periods of water withdrawal. 

Industrial facilities –includes all facilities listed in CWA § 306(b)(1)(A) and all other 

facilities that have a cooling water intake structure in connection with a point source 

thermal discharge. 

Minimize - reduce to the smallest amount, extent or degree reasonably possible. 

Once-through cooling water system - a system designed to withdraw water from a 

natural or other water source, use it at the facility to support contact and/or noncontact 

cooling uses, and then discharge it to a waterbody without recirculation. 

Repowering – the process of increasing the efficiency of older, less efficient industrial 

facilities through the installation of new, improved equipment. Repowering with more 

efficient equipment can significantly reduce non-contact cooling water requirements 

thereby rendering closed-cycle cooling available for an existing industrial facility. 

Repowering includes but is not limited to the partial or complete demolition and 

replacement of the existing industrial facility. 

Wet closed-cycle cooling – a system designed to withdraw the smallest amount of water 

to support contact and/or non-contact cooling uses within a facility. A closed-cycle 

cooling system uses between 93 and 98 percent less water than a once-through cooling 

system. The water is usually sent to a cooling canal, channel, pond, or tower to allow 

waste heat to be dissipated to the atmosphere and then is returned to the system. New 

source water (makeup water) is added to the system to replenish losses that have occurred 

due to cooling tower blow-down, drift, and evaporation. 

Wholly disproportionate test – a comparison of the proportional reduction in impact 

(benefit) as compared to the proportional reduction in revenue (cost) of installing and 

operating BTA technology to mitigate adverse environmental impact. This comparison 

does not monetize the resource and gives presumptive weight to the value of the 

environmental benefits to be gained. 
CP - nn Page 4

IV. Purpose and Background: 

State regulations and federal laws mandate that industrial facilities employ BTA 

to minimize adverse environmental impact when proposing a new or operating an 

existing CWIS. The purpose of this policy is to identify the goals of the Department in 

implementing this standard and to ensure consistent application of those goals to 

industrial facilities in New York State. 

Throughout New York, over 16 billion gallons of water are withdrawn from state 

waters through a CWIS system each day for the purpose of industrial cooling. The 

adverse environmental impact of these CWIS systems is staggering, resulting in over 17 

billion fish of all life stages (eggs, larvae, juveniles and adults) being entrained or 

impinged annually. The fish can suffer from lethally high water temperatures, contact 

with screens, impellers or heat-exchangers, or from exposure to the chemicals used to 

maintain heat-exchanger cleanliness. Steam electric power plants account for the 

majority, though not all, of this environmental impact with some of these power plants 

using well over a billion gallons of water every day for cooling purposes. 

Establishing Closed-Cycle Cooling or the Equivalent as the Performance Goal: 

One of the most efficient and effective ways to minimize or eliminate the number 

of and mortality to aquatic organisms impinged and entrained during industrial cooling is 

to minimize or eliminate the use of once-through, non-contact cooling water from the 

surface waters of New York. The demonstrated technology that achieves the greatest 

reduction in non-contact cooling water use is closed-cycle cooling. Under the U.S. EPA 

CWA 316(b) Phase I Rule (40 C.F.R. Part 125, subpart I), wet closed-cycle cooling was 

identified as the best technology available for new facilities to minimize impingement 

and entrainment, and New York already requires closed-cycle cooling technology to be 

employed on all new facilities and for electric generating facilities being repowered. 

Given the effectiveness of closed-cycle cooling at reducing adverse environmental impact 

caused by a CWIS, and the biological importance of New York’s surface waterbodies for 

commercial and recreational uses, particularly in the marine and coastal district, the tidal 

reach of the Hudson River, and the Great Lakes, this policy establishes closed-cycle 

cooling as the performance goal for all new, existing and repowered industrial facilities in 

New York. 

The Establishment of a Ninety (90) Percent Reduction Minimum Threshold: 

Wet closed-cycle cooling can reduce cooling water requirements by 

approximately 93-98 percent from that required by once-through cooling technology 

depending on the closed-cycle design and the amount of make-up and blow-down water 
CP - nn Page 5

required.F

1

F Where the Department determines that wet closed-cycle cooling is available at 

an existing facility, closed-cycle cooling will be required as BTA to comply with 6 

NYCRR § 704.5. However, due to site-specific conditions, wet closed-cycle cooling may 

not be an available mitigative technology for some existing industrial facilities in New 

York. For a facility where the Department determines that wet closed-cycle cooling is 

not available, the minimum threshold reduction that must be achieved by alternative 

mitigative technologies and/or operational measures is 90 percent of what would 

otherwise be attainable with installation of wet closed-cycle cooling at that facility. 

However, this policy establishes only the minimum reduction goal and the Department 

reserves the right, in any case, to require more stringent protective measures at a 

particular facility and will require the most protective technology and/or operational 

measures available. 

Exemption from the Performance Goal 

An existing electric generating facility operated at less than fifteen (15) percent of 

its electric generating capacity over a current 5-year averaging period may be exempt 

from meeting the performance goals of this policy provided that the reduction in 

operation results in the minimization of the impingement and entrainment of all life 

stages of fish in accordance with this policy. 

Additional Supportive Documentation 

 Additional information on this policy can be found in Appendices A and B. 

Appendix A, BTA Policy Technical Document, provides background information on the 

aquatic impacts associated with the operation of CWIS in New York State, supportive 

documentation on selecting closed-cycle cooling as BTA in New York State, and 

anticipated impacts due to the implementation of this policy. Appendix B, Department 

Procedures for the Determination of “Best Technology Available”, or BTA, under 6 

NYCRR Part 704.5 and Section 316(b) of the Clean Water Act, outlines the procedures 

Department staff use in determining BTA for an industrial facility operating a CWIS in 

connection with a point source thermal discharge. 

V. Responsibility: 

The Division of Fish, Wildlife and Marine Resources has the primary 

responsibility to ensure that BTA determinations are made consistent with this Policy. 

Additionally, the Divisions of Water and Environmental Permits will ensure that the 

requirements of this policy are reflected in all final SPDES permits issued to industrial 

facilities that operate or propose to operate a CWIS in connection with a point source 

thermal discharge. Specific Division responsibilities are as follows: 

Division of Environmental Permits (Permits) - As the Project Manager, Permits 

staff will coordinate the BTA determination with the development of the SPDES 

 

1

 Phase II Rule – 69 Fed.Reg. 41,601, footnote 44 (July 9, 2004). See also Maulbetsch and DiFilippo 

(2008). 
CP - nn Page 6

permit and will provide liaison to the New York State Department of Public 

Service and other state and federal agencies as needed. In addition, Permits staff 

will assess BTA determinations with respect to compliance with Uniform 

Procedures Act (UPA) and State Environmental Quality Review Act (SEQRA) 

requirements. With respect to other land use impacts, Permits staff will seek 

other agency or outside expertise as needed. 

Division of Fish, Wildlife and Marine Resources (DFWMR) - DFWMR staff will 

conduct the biological assessment for and take the lead role in developing the 

BTA determination with respect to aquatic resource impacts. For the SPDES 

permit, DFWMR staff will also assess other fish and wildlife impacts, especially 

within the context of ECL Articles 11, 13, 15, 24 and 25. 

Division of Water (DOW) - DOW Staff will assess BTA determinations with 

respect to water quality impacts and incorporate the final BTA determination into 

the SPDES permit. 

VI. Procedure: 

Implementation of this Policy: 

This policy will be implemented when: (i) an applicant seeks a new SPDES 

permit; (ii) a permittee seeks to renew an existing SPDES permit; or (iii) a SPDES permit 

is modified either by the Department or by the permittee, for a facility that operates a 

CWIS in connection with a point source thermal discharge pursuant to 6 NYCRR § 

704.5; 40 CFR Part 125, subpart I and subpart N; and 40 CFR Part 125.90(b). In 

addition, when issuing SPDES permits for industrial facilities using a CWIS, staff are 

guided by the applicable SPDES regulations, including 6 NYCRR 750-1.11 “Application 

of Standards, Limitations and Other Requirements.” These regulations require that both 

federal minimum requirements and State water quality requirements are met, and that 

other impacts are evaluated and mitigated as required by applicable law and regulations. 

 

DFWMR staff will make final BTA determinations on a site-specific, case by 

case basis following the BTA Determination Procedures (UseeU Appendix B, BTA 

Determination Procedures and Matter of Athens Generating Co., L.P., Interim Decision 

of the Commissioner, June 2, 2000). The BTA determination made under this policy for 

a new SPDES permit or during the renewal or modification of existing SPDES permits is 

only concerned with minimizing the adverse environmental impact associated with a 

CWIS. Once a site-specific BTA determination is made by DFWMR staff, the 

Department will undertake a SEQRA review to ensure that any significant impacts 

associated with the construction and operation of the selected BTA are avoided, 

minimized, or mitigated. In situations where SEQRA does not apply (e.g., Public Service 

Law Article VII siting cases) consideration of the significance of impacts associated with 

construction and operation of the selected BTA, and whether avoidance, minimization or 

mitigation would be appropriate, will occur according to the governing procedural 

statute. 
CP - nn Page 7

Cost Considerations in Making Site Specific BTA Determinations 

After selecting the best technology available for an industrial facility, the 

Department will consider the cost of the feasible technologies and will determine whether 

or not the cost of the technologies are wholly disproportionate to the environmental 

benefits to be gained from the technology. The Department will not undertake a formal 

cost-benefit analysis whereby the environmental benefits would be monetized. Such an 

analysis is neither desirable nor required by law. USeeU Entergy Corp v Riverkeeper, Inc., et 

al., 556 U.S. __, 129 S.Ct. 1498 (2009). For each site-specific BTA determination, the 

Department will select a feasible technology whose costs are not wholly disproportionate 

to the environmental benefits to be gained (UseeU Appendix B, BTA Determination 

Procedures). 

Variances to the Policy’s Performance Goal 

 Other than the exemption due to operating capacity noted previously, the 

Department will not allow facility variances from the performance goals established by 

this policy. Any facility that is unable to meet the performance goals established in this 

policy will need to repower, reduce operations, shut down, or otherwise meet the 

performance goals through a suite of operational measures (e.g., seasonal outages, 

installation of screening mechanisms, variable-speed pumps, etc.). 

Additional Actions Required: 

 The Department is required to make a SEQRA determination prior to the 

implementation of this policy and has determined that the adoption of this policy will not 

have a significant adverse impact on the environment. Rather, adoption of the policy will 

result in greater protection for aquatic resources from the impingement mortality and 

entrainment impacts that result from industrial facilities using surface water for noncontact cooling. The policy will also result in the reduction of withdrawals from surface 

waterbodies and the reduction of thermal impacts at some facilities where the discharge 

of waste heat will be dissipated by the use of cooling towers. 

VII. Related References:

California Environmental Resources Control Board. 2008. Scoping Document: Water 

quality control policy on the use of coastal and estuarine waters for power plant 

cooling. State Water Resources Board. March 2008. 91pp. 

Clean Water Act, 33 U.S.C. §§ 1251 – 1387 

Clean Water Act §§ 306, 316(b) 

Environmental Protection Agency. 1977. Permits Division, Office of Waste Enforcement, 

EPA, Guidance for Evaluating the Adverse Impact of Cooling Water Intake 

Structures on the Aquatic Environment: Section 316(b), PL 92-500 (Draft 1977). 

Entergy Corp. v Riverkeeper, Inc., et al., 556 U.S. __, 129 S.Ct. 1498 (2009). 
CP - nn Page 8

Maulbetsch, John S., and Michael N. DiFilippo. 2008. Performance, Cost, and 

Environmental Effects of Saltwater Cooling Towers. California Energy 

Commission, PIER Energy‐Related Environmental Research Program. 

CEC‐500‐2008‐043. 

Matter of Athens Generating Co., L.P., Interim Decision of the Commissioner, June 2, 

2000 

Matter of Dynegy Northeast Generation, Inc., on behalf of Dynegy Danskammer, LLC,

Decision of the Deputy Commissioner, May 24, 2006 [2006 WL 1488863 

(N.Y.Dept.Env.Conserv.)]; URiverkeeper, Inc. v JohnsonU, 52 AD3d 1072 (3d Dept. 

2008), UappealU UdeniedU 11 NY3d 716 (2009). 

National Pollutant Discharge Elimination System: Regulations Addressing Cooling 

Water Intake Structures for New Facilities; Final Rule, 66 Fed.Reg. 65,255 (Dec. 

18, 2001) (codified at 40 C.F.R. pts. 9, 122-25 [Phase I Rule]. 

National Pollutant Discharge Elimination System: Regulations to Establish Requirements 

for Cooling Water Intake Structures at Phase II Existing Facilities; Final Rule, 69 

Fed.Reg. 41,576 (July 9, 2004) (codified at 40 C.F.R. pts. 9, 122-25) [Phase II 

Rule]. 

NERC (2008). Electric reliability impacts of a mandatory cooling tower rule for existing 

steam generating units, U.S. Department of Energy/North American Electric 

Reliability Corporation: 46 pp. 

Riverkeeper I: Riverkeeper, Inc. et al. v U.S. EPA, 358 F.3d 174 (2d Cir. 2004) 

Riverkeeper II: Riverkeeper, Inc. et al. v U.S. EPA, 475 F.3d 83 (2d Cir. 2007). 

Stark letter (2005) 24 January 2005 letter to EPA B. Grumbles from Deputy 

Commissioner L. Stark. 

Tetra Tech, Inc. 2008. California’s coastal power plants: alternative cooling system 

analysis. Final report to the California Ocean Protection Council. February 2008. 

Title 6 of the Official Compilation of Codes, Rules and Regulations of the State of New 

York (6 NYCRR) Parts 700, 704 and 750. 
Appendix A: BTA Policy Technical Document 

 page 1 of 20 

Establishing Closed-cycle Cooling or the Equivalent as the Best Technology 

Available in New York State for Industrial Facilities 

Background on the Impact to Aquatic Resources

Throughout New York State, over 17 billion gallons of water are withdrawn from 

state waters each day for the purposes of industrial cooling resulting in over 18 billion 

fish of all life stages (eggs, larvae, juveniles and adults) being entrained or impinged 

annually. These fish can suffer from lethally high water temperatures, contact with 

screens, impellers or heat-exchangers, or from exposure to the chemicals used to maintain 

heat-exchanger cleanliness. Steam electric power plants count for the majority, though 

not all, of this impact with some of these power plants using well over a billion gallons of 

water every day for cooling purposes (Table 1). More than 25 steam electric facilities are 

located in New York with almost half of them sited along the East River and the Hudson 

River estuary (Table 2). Other industries in New York requiring non-contact cooling 

water include manufacturing facilities (e.g., cement and sugar industry) and large office 

building facilities. 

Regulatory Requirements 

The Clean Water Act as amended in 1972 includes requirements for the protection 

of fish, shellfish and wildlife from the potential harm caused by the non-contact cooling 

water systems and thermal discharges of industrial facilities. One of the requirements is 

included in Section 316(b) and reads: 

“Any standard established pursuant to section 301 or section 308 of 

this Act and applicable to a point source shall require that the 

location, design, construction, and capacity of cooling water intake 

structures reflect the best technology available for minimizing 

adverse environmental impacts.” See 33 U.S.C. Section 1326(b). 
Appendix A: BTA Policy Technical Document 

 page 2 of 20 

Table 1: Estimated impingement mortality, entrainment and water use at major industrial facilities in New 

York State (MW = megawatts; MGD = million gallons per day). Impingement numbers are absolute and 

do not consider survival off traveling screens. Estimates are based on the most recent site-specific data 

collected (Date). When two dates are indicated, the first date corresponds with entrainment and the second 

date with impingement. Estimated entrainment for the cement plants is based on modeling; no site specific 

data were available. 
Appendix A: BTA Policy Technical Document 

 page 3 of 20 

Table 2: Estimated annual entrainment and impingement by waterbody caused by 

cooling water intake structures at 28 major steam electric facilities in New York State. 

“Other” waterbodies include Cayuga and Seneca Lakes and the Black River. Data are 

summarized from Table 1 estimates. 

In 1974, 6 NYCRR Part 704 became effective with section 704.5 requiring the 

minimization of impacts caused by cooling water intake structures (or CWIS). This 

regulation contains similar language to section 316(b) of the Clean Water Act and states: 

“The location, design, construction, and capacity of cooling water 

intake structures in connection with a point thermal discharge shall 

reflect the best technology available for minimizing adverse 

environmental impact.” 

 In recent years, the U.S. EPA developed and promulgated three phased rules to 

provide formal regulations for states to address the impacts caused by cooling water 

intake structures (CWIS). The Phase I Rule governs all new industrial facilities that 

propose to withdraw two million gallons of water or more each day (MGD) with 25 

percent or more of the water to be used for cooling. This rule establishes the use of wet 

closed-cycle cooling or the equivalent as BTA for all new industrial facilities that meet 

these criteria. The Phase II Rule governed large, existing power plants withdrawing 50 

MGD or more. This rule has since been suspended by the EPA due to a legal decision 

(Riverkeeper II Decision 2007) and a revised draft rule is not anticipated to be released 

until sometime in 2010. The Phase III Rule regulates offshore gas and oil extraction 

facilities. No such facilities exist in the coastal waters of New York State. 
Appendix A: BTA Policy Technical Document 

 page 4 of 20 

Need for a Statewide Policy to Implement Clean Water Act Section 316(b) and 6 

NYCRR Part 704.5

Since 1975, the Department of Environmental Conservation has been responsible 

for ensuring the requirements of CWA § 316(b) are effectively implemented in New 

York State through the State Pollutant Discharge Elimination System (or SPDES) Permit 

Program. However, after more than 30 years of regulating industrial facilities the adverse 

environmental impacts have only been reduced at a few facilities while others have not 

implemented technology or operational measures to minimize impingement mortality 

and/or entrainment. As a result of the failure of the U.S. EPA to effectively promulgate a 

Phase II Rule, no federal guidance or rules exist to set performance requirements for the 

majority of the facilities in New York State regulated under CWA § 316(b) and 6 

NYCRR Part 704.5. This policy sets a performance goal for all new and existing 

industrial facilities throughout New York State based on the best technology available 

that will result in a substantial decrease in adverse environmental impacts caused by 

cooling water intake structures. 

Definition of “Adverse Environmental Impact”

 Regulations and law define the adverse environmental impact that must be 

minimized under CWA § 316(b) and 6 NYCRR Part 704.5 as the number of aquatic 

organisms entrained and impinged by cooling water intake structures (EPA 2001, 

Riverkeeper I Decision 2004, and Riverkeeper II Decision 2007). Industry disagrees with 

this definition and as recently as March 2009, has been attempting to reopen this debate 

before the New York State Supreme Court (Entergy Nuclear Indian Point 2, LLC, and 

Entergy Nuclear Indian Point 3, LLC v. Alexander B. Grannis). 

The “Best Technology Available” or BTA Performance Goal for New York State

The Department establishes closed-cycle cooling or equivalent as the performance 

goal for “Best Technology Available” (BTA) to minimize the adverse environmental 

impacts caused by an industrial facility’s operation of a cooling water intake structure 

(CWIS) in connection with a point source thermal discharge. Furthermore, for an 

existing industrial facility where the Department determines closed-cycle cooling is not 

available, this policy establishes a performance goal of 90 percent or greater reduction in 
Appendix A: BTA Policy Technical Document 

 page 5 of 20 

both entrainment and impingement mortality that would be achieved by installing and 

operating a wet closed-cycle cooling system at that facility. The designation of a 

performance goal requiring a 90 percent reduction of that obtainable using wet closedcycle cooling provides the allowance for a ten percent margin of measurement error 

(Riverkeeper I Decision 2004). Therefore, the appropriate application of this 

performance goal will be for the facility owner to aim for the same reduction in adverse 

impacts obtainable if a closed-cycle cooling system were operated at the facility. 

The reduction in impingement mortality and entrainment required will be 

determined on a site specific, case-by-case basis and will be calculated as follows: 

1. An estimation of impingement mortality and entrainment that would occur 

at a facility assuming that: the cooling water system has been designed as a 

once-through system; the opening of the cooling water intake structure is 

located at, and the face of the standard 3/8-inch mesh conventional traveling 

screen is oriented parallel to, the shoreline near the surface of the source 

waterbody and is operated at the full rated capacity 24 hours a day, 365 days 

a years (e.g., Calculation Baseline) (Riverkeeper v. Johnson 2009, Phase II 

Rule) will be made; 

2. An estimated reduction in impingement mortality and entrainment if the 

facility were to install and operate wet closed-cycle cooling will be made; 

and 

3. If wet closed-cycle cooling is determined to be unavailable for the facility, 

the permittee will be required to demonstrate that by using alternative 

technologies and operational measures impingement mortality and 

entrainment will be reduced by at least 90 percent of that obtainable by step 

No. 2. 

The reductions afforded by closed-cycle cooling will be dependent on the total 

reduction of cooling water withdrawal realized. For marine waters, wet closed-cycle can 

reduce the total amount of water from once-through cooling by 93-95 percent when 

make-up and blowdown flows are minimized (Maulbetsch et al. 2008, EPA 2004). 

Actual reductions in water use at a facility may be lower depending on other air and 
Appendix A: BTA Policy Technical Document 

 page 6 of 20 

water quality restrictions that would restrict the cooling water cycles of concentration 

which for most marine cooling towers would typically be approximately 1.5 cycles 

(Maulbetsch et al. 2008). For freshwater, the reduction is greater: 96-98 percent (EPA 

2004). Therefore, the final, verifiable percent reduction in the adverse environmental 

impact that must be achievable at a facility where closed-cycle cooling is not available

will range from 84-86 percent in marine waters to 86-88 percent or greater in freshwater 

from the calculation baseline. 

Why Choose Closed-cycle Cooling Technology as “BTA”? 

There are many alternative technologies, processes and operational methods to 

closed-cycle cooling that have been demonstrated to reduce entrainment and 

impingement. For some industrial facilities operating once-through cooling systems, 

these alternatives have been demonstrated to reduce entrainment and impingement to 

levels commensurate to that achievable using a closed-cycle cooling system. However, 

the effectiveness of these technologies, especially on reducing mortality, varies greatly 

depending on the facility location, the waterbody drawn from, fish species and life stages 

impinged and entrained, and the ability of the facility owner to maintain and operate the 

equipment effectively. Therefore, it is not possible to select any one of these alternative 

technologies or suites of technologies to install and operate on all existing industrial 

facilities that will consistently, effectively and efficiently minimize the adverse 

environmental impacts caused by CWIS. 

One of the most effective and efficient methods to minimize or eliminate the 

number and mortality of aquatic organisms impinged and entrained during industrial 

cooling is to minimize or eliminate the use of once-through, non-contact cooling water 

from surface waters (EPA 2004, footnote 44). The demonstrated technology that 

achieves the greatest reduction in non-contact cooling water use is closed-cycle cooling. 

Under the U.S. EPA CWA 316(b) Phase I Rule (40 C.F.R. Part 125, subpart I), the EPA 

identified wet closed-cycle cooling as best technology available for new facilities 

requiring non-contact cooling. Prior to the promulgation of the Phase I Rule, New York 

had already required closed-cycle cooling technology to be employed on all new and 

repowered steam electric facilities (Athens Decision 2000). 
Appendix A: BTA Policy Technical Document 

 page 7 of 20 

There are four categories of cooling water systems in use at industrial facilities in 

New York to dispense of waste heat: once-through cooling, wet closed-cycle cooling, dry 

cooling, and hybrid closed-cycle cooling (see Table 3). 

Table 3: Cooling-water system technologies currently in use in New York State. All of the example 

facilities using a dry closed-cycle cooling system are located in the marine district and on the Hudson river 

south of the Federal Dam. 

Cooling Water System Type Description of Technology Examples 

Once-through cooling 

Water withdrawn from waterbody, 

passes through condensers to 

absorb waste heat and returned to 

the source waterbody. Requires 

the most water. 

Most steam electric facilities 

in New York (see Table 1)

Wet Closed-cycle cooling 

Cooling water is recycled. 

Requires 93-98% less water than a 

once-through cooling system. 

Nine Mile Point Nuclear 

Power Plant Unit 2 

Dry Closed-cycle cooling 

Uses the air to transfer heat to the 

atmosphere and requires little to no

water. 

Athens Generating Station; 

New Poletti Station; 

Astoria SCS 

Hybrid closed-cycle cooling 

Combines wet and dry cooling 

technology to reduce vapor 

plumes. Water use commensurate 

with wet closed-cycle. 

Bethlehem Energy Center 

Closed-cycle systems use significantly less water than once through because these 

systems are designed to allow for waste heat to be transferred from the cooling water to 

the atmosphere (by either a reservoir or tower) so the cooling water can be recycled. 

With the exception of some forms of dry-cooling systems, cooling water intake structures 

are still required for many of these closed-cycle systems for the uptake of replacement 

water but the total volume of water required is between 93 and 98 percent less than that 

required with once-through cooling (Maulbetsch et al. 2008, EPA 2002). Albany Steam 

Station (now called Bethlehem Energy Center), located on the Hudson River was 

required to use a closed-cycle cooling system when this facility repowered in 2005. By 

doing so, the owner of Albany Steam Station was able to reduce cooling water use by 

more than 98 percent. This has resulted in an estimated reduction in entrainment of 

98.7% and with the inclusion of wedge wire screens on the intake structure and a low 

intake velocity, impingement mortality has been eliminated. 
Appendix A: BTA Policy Technical Document 

 page 8 of 20 

Dry closed-cycle cooling can eliminate the need for any cooling water 

withdrawals from state waters and has been selected as the appropriate technology for a 

few new industrial facilities sited in New York (Table 3). However, both the U.S. EPA 

and the State of California found this technology is rarely available for retrofitting 

existing facilities due to insurmountable technical and logistical problems (EPA 2004, 

Havey & Blackburn 2008). In addition, both the U.S. EPA and California determined 

that the projected cost of retrofitting existing facilities with dry closed-cycle cooling 

technology could not be reasonably borne by the industry. Nevertheless, the added 

environmental benefits that dry closed-cycle provides over wet closed-cycle is enough for 

New York to identify this technology as the performance goal for new industrial facilities 

sited in the marine and coastal district in New York including the Hudson River up to the 

Federal Dam in Troy. Given that several marine and coastal fish stocks are dangerously 

low (e.g., winter flounder, American shad, Atlantic sturgeon, and river herring), dry 

closed-cycle cooling would provide the greatest environmental benefit to help New York 

marine and coastal fish stocks rebound. In addition, the use of dry closed-cycle cooling 

systems in the marine district would eliminate the potential impact salt water plumes 

associated with wet closed cycle-cooling systems would have on the surrounding 

environment. Dry closed-cycle cooling is already being used at new and repowered 

steam electric power facilities in the marine and coastal district (see Table 3). 

California is developing a policy to establish wet closed-cycle cooling as the 

performance benchmark in meeting the requirements of CWA § 316(b) (CA Env. Protec. 

2008, Appendix A). California’s policy consists of the following two tracks: 

Track 1: An existing power plant must reduce intake flow and intake velocity, at 

a minimum, to a level commensurate with that which can be attained by a closedcycle cooling system; and 

Track 2: If an existing power plant owner or operator demonstrates to the Water 

Board’s satisfaction that Track 1 is not feasible, the power plant must reduce the 

level of adverse environmental impacts from the cooling water intake structure to 

a comparable level to that which would be achieved under Track 1, using 

operational or structural controls, or both. A reduction in environmental impacts 
Appendix A: BTA Policy Technical Document 

 page 9 of 20 

under Track 2 will achieve a “comparable level” if both impingement mortality 

and entrainment of all life stages of marine life are reduced to 90 percent or 

greater of the reduction that would be achieved under Track 1, using closed-cycle 

wet cooling. 

 The State of California has set draft compliance dates of 2018 for non-nuclear 

facilities and 2021 for nuclear facilities. California has also made an exception for 

nuclear steam generating facilities where compliance with the policy will jeopardize 

required health and safety regulations. In these cases, California will make BTA 

decisions on a site specific basis to ensure all safety requirements are met with the 

implementation of BTA. 

Is Closed-cycle Cooling Available at All Existing Industrial Facilities in New York?

 Closed-cycle cooling is required for all new industrial facilities in New York with 

non-contact cooling water needs. However, closed-cycle cooling may not be an available 

technology at many existing facilities in New York State without requiring a major 

reconstruction, or repowering, of the existing plant. Some of the issues that may limit the 

availability of closed-cycle cooling for existing facilities are as follows: 

1. Lack of physical space to site or efficiently operate cooling towers; 

2. Costs wholly disproportionate to benefits due to requiring reconstruction 

of condensers and other infrastructure to site and efficiently operate 

cooling towers; 

3. Facility would not operate efficiently or safely with closed-cycle cooling; 

4. Nuclear Regulatory Commission health and safety requirements will not 

be met; and 

5. Tower drift, fogging, icing, and salt deposition on local neighborhoods, 

roads, and vegetation may have significant impacts. 

Over the past several years, the Department has been making BTA determinations 

using performance goals based on the Phase II Rule requirements (60-90% reduction in 

entrainment and 80-95% reduction in impingement mortality)(Riverkeeper v. Johnson 

2009, Stark 2005 letter to EPA). Since 2004, the Department has completed BTA 

determination for six existing industrial facilities resulting in an average estimated 

reduction in impingement mortality of 89 percent and entrainment by 72 percent (Table 

4). Closed-cycle cooling is likely not available for these facilities for one or more of the 
Appendix A: BTA Policy Technical Document 

 page 10 of 20 

above stated reasons; therefore the Department selected the next best available 

technology to minimize impingement mortality and entrainment. Without retrofitting 

these facilities with closed-cycle cooling, four of the six facilities would likely meet the 

performance goal established by this policy for impingement mortality reduction but it is 

possible that only one facility would meet the goal for entrainment reduction with the 

currently selected BTA. Additional technologies and operational measures would be 

required.

Table 4: Estimated reductions in impingement mortality and entrainment obtainable at facilities recently 

implementing Department selected BTA. Closed-cycle cooling is likely not available for these facilities 

without repowering. It will likely be the most difficult for facilities to meet the performance goals for 

entrainment. Note that World Trade Center will be implementing a partial closed-loop cooling system as 

part of the BTA determination. The Policy Based Reduction ranges listed in this table include both 

impingement mortality and entrainment. 

 

Alternative Technologies, Processes and Operational Methods That Reduce 

Entrainment and Impingement Mortality 

There are many technologies, processes and operational measures that have been 

demonstrated to reduce entrainment and impingement mortality (Table 5). For some 

industrial facilities, these alternatives have been demonstrated to reduce entrainment and 

impingement mortality to levels commensurate to that achievable using closed-cycle 

cooling. Prior to its closing in 2008, the Lovett Generating Station on the Hudson River 

had seasonally employed filter fabric technology (Gunderboom Marine Life Exclusion 

System or MLESTM) resulting in a reduction in entrainment and impingement greater 

than 90 percent from plant operations prior to the use of this technology. Bowline Point 

generating station was able to reduce impingement mortality by 91 percent using an 
Appendix A: BTA Policy Technical Document 

 page 11 of 20 

exclusion barrier net (Hutchinson and Matouse 1988). However, for most facilities, a 

combination of physical barriers, fish return systems, and deterrent systems along with 

flow reductions and outages would be required to reduce entrainment and impingement 

mortality to 90 percent of that achievable using wet closed-cycle technology. 

Table 5: Alternative technologies to closed-cycle cooling that are used in New York and have been 

demonstrated to reduce levels of entrainment and impingement mortality (modified from Taft and Cook 

2003). 

Technology 

Category Technologies Mode of Action Where Used in 

New York 

Physical Barriers - Wedge wire screens 

- Barrier nets 

- Aquatic filter barriers 

Physically block fish 

passage (usually in 

combination with low 

water velocity) 

Brooklyn Navy Yard 

Somerset 

Lovett 

Bowline Point 

Ravenswood 

Bethlehem Energy Center 

Collection/Return 

Systems 

- Conventional Traveling 

 Screens 

- Ristroph Traveling 

 Screens 

- Fine Mesh Traveling 

 Screens 

- Fish pumps 

Actively or passively 

collect fish for 

transport through a 

return system 

Arthur Kill 

Black River 

Danskammer 

Oswego Steam 

E.F. Barrett 

Far Rockaway 

Indian Point 

Ravenswood 

Somerset 

Dunkirk 

Huntley 

Port Jefferson 

Roseton 

Diversion Systems Angled screens Divert fish to a return 

system or safe area 

Oswego Steam 

Flow Reduction Variable Speed Drive 

 Pumps 

Closely match cooling 

water use to heat load 

Danskammer 

Arthur Kill 

Astoria 

Behavioral 

Deterrent 

Technologies 

Acoustic systems Alter or take 

advantage of natural 

behavior patterns to 

repel or attract fish 

James A. Fitzpatrick 

Danskammer 

Anticipated BTA Policy Compliance Costs to Industry

To estimate the compliance cost industry would have to bear with the 

implementation of this policy, some assumptions had to be made and several sources of 

public information and data were relied upon. Since the cost of retrofitting and operating 

a wet closed-cycle cooling system on a facility is directly related to the amount of cooling 

water used and the heat load that is required to be dissipated, the steam electric 

generating industry would bear the greatest cost to comply with this policy. 
Appendix A: BTA Policy Technical Document 

 page 12 of 20 

Though other manufacturing facilities would also be required to comply with the 

policy, the overall cost would be significantly less than that for the steam electric 

industry. In fact, the U.S. EPA found that for new manufacturing facilities, the total 

annualized compliance costs to install and operate wet closed-cycle cooling were below 

0.5 percent of gross annual revenues for several industries (e.g., pulp & paper, chemicals, 

petroleum, steel and aluminum) (EPA 2005). In the same document, the EPA estimated 

compliance costs to the steam electric industry would be much higher, at greater than five 

percent gross annual revenues for some facilities but still determined that the industry as 

a whole could bear this cost. The U.S. EPA had previously rejected dry closed-cycle 

cooling as the performance benchmark in the Phase I Rule, which applies to all new 

industrial facilities, with cost estimates exceeding ten percent of gross revenues for many 

proposed facilities. The U.S. EPA considers costs greater than 10 percent of gross 

revenue could be a barrier for new facilities to enter the industry (EPA 2001). However, 

in New York, new steam electric facilities have recently been constructed that utilize dry 

closed-cycle cooling technology clearly demonstrating that this technology is in fact 

economically achievable. 

Compliance costs listed in Table 6 were only generated for the existing steam 

electric generating facilities in New York with the assumption that wet closed-cycle 

cooling is available for all existing plants. Given the large amount of revenue 

information available for the steam electric generating industry, it is possible to estimate 

the overall cost of compliance the implementation of this policy will have. Revenue was 

estimated by calculating the average net energy production (in MWh) for each facility for 

the period from 2002 to 2007 from the NYISO Load and Capacity Data “Gold Books” 

(2003-2008) and multiply that number by the average zonal price per MWh reported for 

2007. This revenue was then projected for 20 years which is the approximate functional 

life of wet cooling towers before major maintenance and reconstruction is required 

(Havey and Blackburn 2008). 

 The cost to construct and operate cooling towers at each facility was estimated 

using the relationship between costs and cooling water use in gallons per minute (gpm) 

reported by Maulbetsch (2005). In order to determine a current cost per gpm, the median 
Appendix A: BTA Policy Technical Document 

 page 13 of 20 

cost of $555 per gpm was calculated using the costing data provided in Havey and 

Blackburn (2008) for 11 steam electric facilities in California. Annual cooling tower 

operation and maintenance costs were estimated using the relational factor to capital cost 

of 1.6 percent reported by Maulbetsch (2005). By applying these cost factors to existing 

New York steam electric facilities, it is estimated that the compliance cost for the steam 

electric industry over 20 years would be over $8.5 billion (Table 6). This would be 

approximately 6.7 percent of the gross annual revenues for the industry for this time 

period. If Oswego Power were not included in the estimation, the overall cost of 

compliance would fall to 6.2 percent of revenue. At present, Oswego Steam operates at 

less than three percent capacity. 

For steam electric facilities where wet closed-cycle is not feasible, the costs of 

alternative technologies are generally much less costly than cooling towers for most 

facilities in New York State (Table 7). EPA estimated that for 99 percent of the firms 

across the country that own large power plants, compliance costs for implementing these 

other technologies under the Phase II Rule would be less than three percent of revenues 

(EPA 2004). However, some facilities will likely not meet the performance goals set by 

this policy by utilizing alternative feasible technologies and would likely be required to 

reduce cooling water use further by reducing electric generating capacity. This could 

significantly reduce revenue for these facilities. 
Appendix A: BTA Policy Technical Document 

 page 14 of 20 

Table 6: Estimated compliance costs for the steam electric industry in New York State. Note that Oswego 

Steam Station operated on average less than 3.0% of capacity. Parasitic and efficiency losses are not 

included. 

Table 7: Estimated costs of installing alternative technologies at existing steam electric facilities in 

New York State. 

Estimated 

Costs*: 

Ristroph 

Screens Wedge wire 

Variable 

Speed 

Pumps 

Fish 

Deterrent 

Systems Barrier Nets

Average $9,920,476 $20,019,002 $39,306,075 $2,248,500 $5,173,333

Maximum $18,689,000 $65,000,000 $55,657,000 $3,050,000 $8,000,000

Minimum $3,746,000 $3,892,000 $16,400,000 $1,447,000 $3,539,000

*All estimates include construction and 20-year operation and maintenance expenses. All 

cost estimates are based on data provided to New York State for 12 steam electric facilities. 

Cost Considerations in Implementing the Performance Goals of this Policy 

Cost-Benefit Analysis 

The U.S. Supreme Court (2009) determined that it is up to the discretion of the 

U.S. EPA, or the U.S. EPA’s designee, to determine how costs will be considered when 

establishing requirements to minimize the adverse environmental impacts caused by 

CWIS. The Court decided that the need for, and the rigor of a cost-benefit analysis were 

rightly left to the U.S. EPA’s discretion when they established the performance standards 
Appendix A: BTA Policy Technical Document 

 page 15 of 20 

in the Phase II Rule (Entergy v. Riverkeeper, Inc. 2009 Decision). The Supreme Court 

decision reverses the 2007 U.S. Court of Appeals, Second Circuit decision which ruled 

that the U.S. EPA was prohibited from making cost-benefit analyses under CWA § 

316(b) (Riverkeeper II 2007 Decision). 

Prior to the 2007 decision of the Second Circuit Court of Appeals, the Department 

had been making BTA determinations in New York for individual facilities on a sitespecific, case by case basis (Athens Decision 2000). For each site-specific BTA 

determination, the Department selected a feasible technology whose costs were not 

wholly disproportionate to the environmental benefits expected to be gained. (Athens 

Decision 2000). 

Wholly Disproportionate Test 

The Department contends that the only relevant environmental benefit to be 

considered in any CWA §316(b)/6 NYCRR §704.5 BTA analysis is the reduction in 

impingement mortality and entrainment of fish and shellfish, afforded by the 

minimization alternative (Stark letter 2005, Athens Decision 2000). The selection of the 

BTA is a technology forcing decision but the Department will select technologies that are 

not wholly disproportionate to the environmental benefits (Stark letter 2005, Athens 

Decision 2000). In the 2000 Athens Interim Decision the Commissioner stated “.....a 

lone finding that costs outweigh environmental benefits to be gained is insufficient; 

instead, a finding must be made that the costs are “wholly disproportionate” to the 

environmental benefits to be gained. This more rigorous standard gives presumptive 

weight to the value of the environmental benefits and places the burden on a permit 

applicant to demonstrate that the relative costs are unreasonable.” The Department will 

continue to use the wholly disproportionate test when determining BTA on a site-specific 

basis. 

Costs Reasonably Borne by the Industry

The estimated compliance cost for the performance goals stated in this policy for 

existing facilities in New York State is 6.7 percent of revenue with 11 facilities falling 

below six percent (Table 6). Unfortunately, no specific threshold is available for the 

electric generation industry for determining an absolute threshold for cost reasonably 
Appendix A: BTA Policy Technical Document 

 page 16 of 20 

borne, but based on several EPA documents, a range around such a threshold can be 

estimated. In establishing the Phase I Rule, the EPA rejected dry cooling citing that the 

annualized compliance costs would be “.... greater than 4 percent of revenues for all of 

83 projected electric generators within the scope of the rule. For 12 generators, costs 

would exceed 10% of revenues. EPA has determined that higher capital and operating 

costs associated with dry cooling may pose barrier to entry for some new sources in 

certain circumstances. (In general, barrier to entry means that it is too costly for a new 

facility to enter into the marketplace).” (EPA 2001). The EPA decided that industry on 

the whole could not bear the cost of dry closed-cycle technology. 

The EPA (2006) also stated that small entities (not electric generating facilities) 

with annualized compliance costs that equal or exceed three percent of revenue might

experience a significant financial impact. Thus, costs less than three percent can be 

assumed to be generally achievable. Costs that exceed three percent of revenue may still 

be economically achievable but achievability would depend on the specific industry in 

question since operating margins and profit margins vary by industry. The EPA (Putnam 

et al. 1982) estimated that a cost of greater than six percent of revenue might not be 

economically achievable for the perfumes and cosmetics industry. 

The EPA ultimately settled on wet closed-cycle cooling to set the performance 

requirements under the Phase I Rule after finding that the compliance costs for new 

electric generators ranges between 0.07 and 5.24 percent of annual gross revenue. Under 

the Phase II Rule, the EPA concluded that the costs of technologies, other than closedcycle cooling, to minimize impingement and entrainment could be borne by the industry 

since compliance costs for implementing these other technologies would be less than 

three percent of revenues for 99 percent of the existing steam electric facilities (EPA 

2004). 

While this information provides some insight into the financial condition of the 

electric generation industry, the upper threshold is still unclear. However, the “magic 

number” of what could be reasonably borne by a specific industry most likely falls 

between three and ten percent. 
Appendix A: BTA Policy Technical Document 

 page 17 of 20 

Energy Capacity and Reliability Issues 

 Retrofitting wet closed-cycle cooling towers onto existing steam electric facilities 

originally designed for once-through cooling will have an impact on the existing energy 

capacity and reliability in New York State (DOE 2008). Reliability can be affected by 

the long durations of plant shutdown required for the switch over. Total capacity of the 

electrical system will be reduced by parasitic losses that include the energy required to 

run the fans and pumps associated with the cooling towers and the loss of capacity due to 

losses in efficiency. For some facilities, these efficiency losses can be mitigated by 

increasing thermal input to generate more electricity. However, this will not be available 

for all facilities especially pressure water nuclear reactors and some combined cycle 

facilities (Havey and Blackburn 2008). For these facilities, additional energy will be 

required to be imported to make up for these losses which if not wind or hydro generated, 

will likely be generated by coal or natural gas facilities. Considering that the coal and 

natural gas steam facilities would also be required to make up the lost capacity to comply 

with this policy, additional capacity will need to be added to the grid. 

 Approximately 80 percent of New York State’s electric generating capacity 

consists of nuclear, natural gas, coal, and oil fueled generating facilities (NYISO 2008). 

The remaining 20 percent is shared by hydro, wind, solar, solid waste, and biomass 

generators. The North American Electric Reliability Corporation estimates that the total 

energy generation capacity in the United States would be reduced by 4.3 percent with the 

retrofitting of existing steam electric facilities with closed-cycle cooling (DOE 2008). 

New energy production would be required to offset these losses and based on the total 

energy generated in New York State in 2007 (NYISO 2008), this would come to 

approximately 4,813 GWh of electricity required or the equivalent of a new 550 MW 

steam turbine unit operating at full-generating capacity.

Additional Impacts of this Policy to Natural Resources 

In making a BTA determination, the only adverse environmental impact that will 

be taken into consideration is the reduction in impingement mortality and entrainment of 

fish afforded by the minimization alternative (Athens 2000). After the BTA 

determination is made, the Department will make a SEQRA determination on the facility 
Appendix A: BTA Policy Technical Document 

 page 18 of 20 

specific SPDES permit prior to issuance (Indian Point Interim Decision 2008). 

Implementing this policy at a facility may have an impact on the following natural 

resources (note that this is not an exhaustive list): 

1. Air resources caused by the operation of cooling towers with both an increase 

in air borne pollutants (i.e., carbon, nitrogen, sulfur, mercury) due to 

additional power generation required to offset power losses associated with 

the operation of cooling towers and the localized effect of cooling tower drift; 

2. The potential of localized fogging, icing and salt deposition caused by cooling 

tower water vapor plumes; 

3. Visual impacts of cooling towers on the local communities and open spaces; 

4. Local impacts caused by the physical construction of towers and potential loss 

of protected wetlands and other wildlife habitat and open space; and 

5. Local noise ordinances caused by the operation of mechanical draft towers. 

Literature Cited: 

Athens Decision 2000: Matter of Athens Generating Co., L.P., Interim Decision of the 

Commissioner, June 2, 2000. 

California Envrtl. Protec. Agency, Water Resources Control Board. 2008. Scoping 

Document: Water quality control policy on the use of coastal and estuarine 

waters for power plant cooling. March 2008. 91pp. 

Clean Water Act. 33 U.S.C. Sections 1251 – 1387 

Clean Water Act Sections 306, 316(b) 

DOE 2008. Electricity Reliability Impacts of a Mandatory Cooling Tower Rule of 

Existing Steam Generating Units. U.S. Department of Energy, Office of 

Electricity Delivery and Energy Reliability. October 2008. 

DOE 2007. Electric Power Annual 2007, Revised Data, January 2009. Energy 

Information Administration, U.S. Department of Energy. 

(http://www.eia.doe.gov/cneaf/electricity/epa/epaxlfile8_1.xls) 

Entergy v. Riverkeeper, Inc. 2009 Decision. 556 U.S. Supreme Court. _____(2009) 

Environmental Protection Agency (2001). Phase I—New Facilities Economic Analysis of 

the Final Regulations. EPA-821-R-01-035. 

EPA 2001. Environmental Protection Agency; National Pollutant Discharge Elimination 

System: Regulations Addressing Cooling Water Intake Structures for New 

Facilities; Final Rule; 18 December 2001; 66 Fed. Reg. 65256 

EPA 2002. Phase II Existing Facility Technical Development Document. EPA-821-R-02-

003. 
Appendix A: BTA Policy Technical Document 

 page 19 of 20 

EPA 2004. Environmental Protection Agency; National Pollutant Discharge Elimination 

System: Final Regulations to Establish Requirements for Cooling Water Intake 

Structures at Phase II Existing Facilities; Final Rule, 69 Fed. Reg. 41576 

(7/9/2004) 

EPA 2005. Environmental Protection Agency. Preliminary Economic Profile: Steam 

Electric Detailed Study; August 2005. 821-B-05-006. 

EPA 2006: Environmental Protection Agency; Economic and Benefits Analysis for the 

Final Section 316(b) Phase III Existing Facilities Rule ; June 1, 2006; Section D1-

2.3 ; Page D1-10 

Hutchinson Jr., J. B. and J. A. Matouse (1988). Evaluation of a barrier net used to 

mitigate fish impingment at a Hudson River Power Plant Intake. Science, Law, 

and Hudson River power plants: a case study in environmental impact assessment. 

L. W. Barnthouse, R. J. Klauda, D. S. Vaughan and R. L. Kendall. Bethesda, MD, 

American Fisheries Society Monograph 4: 280-285. 

Havey and Blackburn (2008). California’s coastal power plants: alternative cooling 

system analysis. Final report to the California Ocean Protection Council. February 

2008. 

Indian Point Interim Decision 2008: In the Matter of Entergy Nuclear Indian Point 2, 

LLC and Entergy Nuclear Indian Point 3, LLC, Interim Decision of the 

Commissioner, August 13, 2008. 

Kennecott v. U. S. Envtl. Protect. Agency, C.A. 4, 1985. Westlaw 780 F.2d 445. 

Maulbetsch, John S., and Michael N. DiFilippo. 2008. Performance, Cost, and 

Environmental Effects of Saltwater Cooling Towers. California Energy 

Commission, PIER Energy‐Related Environmental Research Program. 

CEC‐500‐2008‐043. 

Maulbetsch (2003). An Overview of Fish Protection Technologies and Cooling Water 

Intake Structures (CWISs). In A Symposium on Cooling Water Intake 

Technologies to Protect Aquatic Organisms. May 6-7, 2003. Arlington VA. EPA 

625-C-05-002. p. 112-125. 

NERC (2008). Electric reliability impacts of a mandatory cooling tower rule for existing 

steam generating units, U.S. Department of Energy/North American Electric 

Reliability Corporation: 46 pp. 

NYISO (2003). Load and Capacity Data “Gold Book”. April 2003. 

NYISO (2004) Load and Capacity Data “Gold Book”. April 2004. 

NYISO (2005) Load and Capacity Data “Gold Book”. April 2005. 

NYISO (2006) Load and Capacity Data “Gold Book”. April 2006. 

NYISO (2007) Load and Capacity Data “Gold Book”. April 2007. 

NYISO (2008) Load and Capacity Data “Gold Book”. April 2008. 
Appendix A: BTA Policy Technical Document 

 page 20 of 20 

Riverkeeper I Decision 2004: Riverkeeper, Inc. et al. v. U. S. Envtl. Protect. Agency, (2nd

Cir. 3 February 2004). 

Riverkeeper II Decision 2007: Riverkeeper, Inc. et al. v. U. S. Envtl. Protect. Agency, (2nd

Cir. 25 January 2007). 

Riverkeeper v. Johnson, NYSDEC, 2009. Matter of Dynegy Northeast Generation, Inc., 

on behalf of Dynegy Danskammer, LLC, Decision of the Deputy Commissioner, 

May 24, 2006 [2006 WL 1488863 (N.Y.Dept.Env.Conserv.)]; Riverkeeper, Inc. v 

Johnson, 52 AD3d 1072 (3d Dept. 2008), appeal denied 11 NY3d 716 (2009). 

Taft, N. and T. Cook (2003). An Overview of Fish Protection Technologies and Cooling 

Water Intake Structures (CWISs). In A Symposium on Cooling Water Intake 

Technologies to Protect Aquatic Organisms. May 6-7, 2003. Arlington VA. EPA 

625-C-05-002. p. 8-23. 

Title 6 of the Official Compilation of Codes, Rules and Regulations (6 NYCRR) Parts 

704 and 750. 

Phase I Rule. Federal Register Vol. 66, No. 243. Rules and Regulations. December 18, 

2001. 

Phase II Rule. Federal Register Vol. 69, No. 131. Rules and Regulations. July 9, 2004. 

Putnam, Hayes & Bartlett, Inc. (1982) Workbook for Determining Economic 

Achievability for National Pollution Discharge Elimination System Permits. Final 

Report to U.S. EPA. August 1982. 

Stark, L. (2005). 4 January 2005 letter to Mr. Benjamin H. Grumbles of the U.S. EPA. 
Appendix B: Department Procedures for Determining “Best Technology Available” 

Alexander B. Grannis 

 Commissioner 

New York State Department of Environmental Conservation 

Division of Fish, Wildlife & Marine Resources 

Bureau of Habitat, 5th Floor 

625 Broadway, Albany, New York 12233-4756 

Phone (518) 402-8924 • Fax: (518) 402-8925 

Website: www.dec.ny.gov

 ----- DRAFT ----- 

Department Procedures for the Determination of “Best Technology Available”, or BTA, 

Under 6 NYCRR Part 704.5 and Section 316(b) of the Clean Water Act 

 Consistent with our responsibilities under 6 NYCRR Part 704.5, other SPDES 

regulations, appropriate case law and Commissioners’ decisions (see References), and the 

federal Clean Water Act, staff of the Steam Electric Unit should use the following procedure 

when making “Best Technology Available” (BTA) determinations at power plants and other 

facilities having cooling water intake structures (CWIS). The purpose of the BTA determination 

is to identify the best technology available for minimizing adverse environmental impact from 

the cooling water intake structure. Prior to following the procedures in this document, staff will 

determine whether the facility’s CWIS is causing or may result in an adverse environmental 

impact. The adverse environmental impact being assessed is the mortality of fish caused by 

impingement and entrainment. This assessment will be made by reviewing the results of 

previous impingement mortality and entrainment studies conducted at the facility and/or by 

requiring the applicant or facility owner to conduct additional biological studies. 

Step 1

Staff, in conjunction with the applicant or facility owner, will develop an array of 

potential alternatives for minimizing adverse environmental impact that are considered 

feasible with respect to the physical properties of the site and the specifications of the 

proposed or existing cooling water intake structure (location, design, construction and 

capacity). Feasible means Acapable of being done@ and does not involve consideration of 

cost. Staff will require the applicant or facility owner to provide an analysis of these 

alternatives that evaluates both the effectiveness at protecting aquatic resources and the 

cost of implementation. Staff may require the applicant or facility owner to evaluate 

alternatives not endorsed by the applicant or facility owner but that staff believe are 

feasible. Finally, the applicant or facility owner will be required to propose an alternative 

or array of alternatives that they believe will achieve BTA. 
Page 2 of 5 

Step 2 

Next, staff will consider the standards for aquatic resource protection contained in 

Section 316(b) of the Clean Water Act. For new facilities regulated by the 40 CFR Part 

125 - Subpart I (Phase I Rule), any feasible alternatives or combination of feasible 

alternatives from Step 1 that do not provide aquatic resource protection at least 

equivalent to the protection afforded by closed-cycle cooling will be eliminated from 

further consideration as BTA. For existing power plants regulated by 316(b) of the Clean 

Water Act, any feasible alternatives or combination of feasible alternatives from Step 1 

that do not provide a 90 percent or greater reduction in both entrainment and 

impingement mortality from that which would be achieved by a wet closed-cycle cooling 

system will be eliminated from further consideration as BTA. 

Step 3 

For each of the mitigation alternatives remaining after conducting Step 2, staff will 

consider the extent to which adverse environmental impacts are minimized. Minimize

means reduce to the smallest amount, extent or degree reasonably possible. Adverse 

environmental impact means impact resulting in any injury or mortality of aquatic 

organisms caused by impingement and/or entrainment. Staff will then determine whether 

minimizing adverse environmental impact is wholly disproportionate to the resulting 

aquatic resource benefit1

 (i.e., increase in the level of aquatic resource protection) using 

cost information provided by the applicant or facility owner, and other publicly-available 

information, as appropriate. Staff will not perform a formal cost-benefit analysis; 

however, they will use a quantitative approach when making this determination. The 

analysis will not be done on the basis of absolute value (the cost of the mitigation 

alternative compared to the value of the aquatic resource benefit) because there is no 

generally agreed upon methodology for placing a dollar value on environmental benefits. 

Instead, staff will compare relative changes in cost when assessing the effectiveness of 

the different mitigation alternatives. Cost and benefits will be aggregated over the 

expected life of the facility. If the applicant or facility owner does not provide 

information on the expected life of the facility and no other information is available, staff 

will use 20 years as a default time frame. 

Cost.B Cost will be assessed using the proportional cost of the mitigation 

alternative when compared to either total cost or total revenues. Proportional cost 

for an existing facility will be expressed as the ratio of the cost of the mitigation 

alternative (construction plus operation and maintenance) to the projected 

 1

 See discussion regarding Matter of Athens Generating Co., L.P., Interim Decision 

of the Commissioner, June 2, 2000 Matter of Mirant Bowline, LLC, Decision of 

the Commissioner, March 19, 2002, page 14-26. 
Page 3 of 5 

revenues for that facility. Proportional cost for new facilities will be expressed as 

the ratio of the cost of the mitigation alternative (construction plus operation and 

maintenance) to either the total cost for the proposed facility (capital plus 

operation and maintenance), or the projected revenues for the proposed facility. 

These costs will be aggregated over the life of the facility and calculated as shown 

below. 

 Cost of mitigative technology 

 Proportional cost (C) = --------------------------------------------

 Total cost (or revenues) 

Benefit.B As with cost, staff will assess the proportional aquatic resource benefit 

(or effectiveness) of the mitigation alternative. Effectiveness will be measured as 

the proportional change in the number of vulnerable aquatic organisms estimated 

to be protected by the mitigation alternative compared to the number at risk. 

Vulnerable organisms are those which would be killed by impingement or 

entrainment if the plant used a once-through cooling system without any 

additional mitigation2

. Aquatic resource benefits will be aggregated over the life 

of the facility and calculated as shown below. 

 Number of organisms protected with mitigative technology 

 Proportional benefit (B) = ---------------------------------------------------------------------------------------

 Number of organisms at risk of impingement/entrainment mortality 

The results of the cost effectiveness comparison will be expressed as a narrative: AAn 

increase in facility expenditures of [C x 100] percent would yield a [B x 100] percent 

increase in aquatic resource protection.@ 

This process provides a way to develop a cost - benefit comparison to determine whether 

the cost is wholly disproportionate. Staff will use statutes, case law, Commissioner=s 

decisions, guidance documents3

, and professional judgment to determine whether the cost 

 2

 compared with baseline impingement and entrainment when the facility is 

operating at full flow and full capacity - See Matter of Dynegy Northeast 

Generation, Inc., on behalf of Dynegy Danskammer, LLC, Decision of the Deputy 

Commissioner, May 24, 2006 [2006 WL 1488863 (N.Y.Dept.Env.Conserv.)]; 

Riverkeeper, Inc. v Johnson, 52 AD3d 1072 (3d Dept. 2008), appeal denied 11 

NY3d 716 (2009). 

3

 See Technical and Operational Guidance Series (TOGS), 1.2.1, Section I.B.2.b 

which references USEPA 1982. 
Page 4 of 5 

of the mitigation alternative is wholly disproportionate to the aquatic resource benefits 

(i.e., increase in the level of aquatic resource protection). 

Any of the feasible alternatives from Step 3 with cost determined to be wholly 

disproportionate to the benefits provided will be eliminated from consideration as BTA. 

 Step 4 

Of the alternatives remaining after Step 3, staff will identify as the most protective 

alternative the one that most effectively minimizes adverse environmental impacts. Staff 

then will use professional judgment in making a site-specific determination of: a) 

whether the level of mitigation provided by the most protective alternative is reasonable 

and necessary for minimizing adverse environmental impacts at the facility, b) whether 

the alternative or array of alternatives proposed by the applicant or facility owner will 

achieve BTA, and c) whether one or more of the other remaining alternatives can achieve 

an approximately equivalent level of mitigation as the most protective alternative. 

Step 5 

As a final step in the process, staff will identify the preferred alternative and develop a 

narrative explanation of the reasons for selecting the preferred alternative and rejecting 

other feasible alternatives. This narrative should form the basis of the analysis of 

alternatives presented in the Biological Fact Sheet for the SPDES permit for the facility. 

References: 

New York 

Letter to Environmental Energy Alliance of New York Director John G. Holsapple 

from DEC Executive Deputy Commissioner Denise M. Sheehan, dated January 

31, 2005. 

Matter of Dynegy Northeast Generation, Inc., on behalf of Dynegy Danskammer, LLC,

Decision of the Deputy Commissioner, May 24, 2006 [2006 WL 1488863 

(N.Y.Dept.Env.Conserv.)]; Riverkeeper, Inc. v Johnson, 52 AD3d 1072 (3d Dept. 

2008), appeal denied 11 NY3d 716 (2009). 

Matter of Athens Generating Co., L.P., Interim Decision of the Commissioner, June 

2, 2000 Matter of Mirant Bowline, LLC, Decision of the Commissioner, March 

19, 2002. 

Title 6 of the Official Compilation of Codes, Rules and Regulations (6 NYCRR) 

Parts 700, 704 and 750. 
Page 5 of 5 

Federal 

Entergy Corp. v Riverkeeper, Inc., et al., 556 U.S. __, 129 S.Ct. 1498 (2009). 

EPA 2001. Environmental Protection Agency; National Pollutant Discharge 

Elimination System: Regulations Addressing Cooling Water Intake Structures for 

New Facilities; Final Rule; 66 Fed. Reg. 65256 (12/18/2001). 

In re Brunswick Steam Electric Plant, 1976 WL 25235, (E.P.A.G.C.). 

Riverkeeper, Inc. v. U.S. Envtl. Protect. Agency, 358 F.3d 174, 189-92 (2nd Cir. 3 

February 2004). 

Riverkeeper, Inc. v. U.S. Envtl. Protect. Agency, (2nd Cir. 25 January 2007). 

Seacoast Anti-Pollution League v. Costle, 597 F.2d 306 (1st Cir. 1979). 

 Guidance Documents 

Commissioner Policy-nn. Best Technology Available (BTA) for Cooling Water 

Intake Structures. (Draft 2010). 

USEPA. 1982. Work book for determining economic achievability for national 

pollution discharge elimination system permits. Prepared by Putnam, Hayes, and 

Bartlett, Inc. (August 1982). 

USEPA. Permits Division, Office of Waste Enforcement, EPA, Guidance for Evaluating 

the Adverse Impact of Cooling Water Intake Structures on the Aquatic Environment: 

Section 316(b) PL 92-500. (Draft 1977).