Tetra Tech, Inc.

10306 Eaton Place, Suite 340

Fairfax, VA 22030

phone 703-385-6000

TO: Paul Shriner and Jan Matuszko, USEPA

FROM: John Sunda, SAIC and Kelly Meadows

DATE: June 11, 2010

SUBJECT: Cooling Tower Noise

EPA tasked SAIC and Tetra Tech with evaluating 

abatement technologies may be developed for a universe of facilities potentially subject 

to closed-cycle cooling under the proposed 

presents a brief overview of abatement technologies 

possible approaches for incorporating these costs 

Noise Abatement 

Background

When installing cooling towers at power plants

consideration must be given to noise impacts. 

noise ordinances may be as low as 50 

mechanical draft cooling tower

distance of 500 ft (SPX 2010a)

the noise dissipates as the distance increases. 

distances of less than half the

dBA for each doubling of the

the noise level will dissipate roughly 6 

this rule-of-thumb, the nearest receptor would need to be 

 

1 As an example, a study conducted for the Manchester Street Station (CH2MHill 2009) indicated that the 

noise regulations in Sections 16-91 through 16

Code required the following:

 In the absence of specific maximum noise levels, a noise level that exceeds the ambient noise by 5 

dBA or more at the nearest property line or a noise audible at 200 feet is defined as unnecessary, 

excessive, or offensive noise.

 It is unlawful to operate equipment in any residen

between 8 p.m. and 7 a.m. or exceed 55 dBA between 7 a.m. and 8 p.m.

MEMORANDUM

10306 Eaton Place, Suite 340

Paul Shriner and Jan Matuszko, USEPA

John Sunda, SAIC and Kelly Meadows

, 2010

Cooling Tower Noise, Plume and Drift Abatement Costs 

EPA tasked SAIC and Tetra Tech with evaluating how costs for noise, plume 

abatement technologies may be developed for a universe of facilities potentially subject 

under the proposed existing facility rulemaking. This memo 

of abatement technologies and associated costs and presents 

possible approaches for incorporating these costs into the proposed rule.

When installing cooling towers at power plants close to residential and commercial areas

consideration must be given to noise impacts. For plants close to residential areas

may be as low as 50 dBA, especially at night.

1

For a conventional 

mechanical draft cooling tower, sound levels of about 60 dBA can be expected at a 

(SPX 2010a). Distance to the nearest receptor is an important

as the distance increases. The general rule-of-thumb is that at 

the length of the tower, the noise level will dissipate roughly 3 

for each doubling of the distance, and at distances greater than half the tower length, 

the noise level will dissipate roughly 6 dBA for each doubling of the distance.

thumb, the nearest receptor would need to be at least 1,600 ft from 

 

As an example, a study conducted for the Manchester Street Station (CH2MHill 2009) indicated that the 

91 through 16-109 of the City of Providence, Rhode Island Municipal 

fic maximum noise levels, a noise level that exceeds the ambient noise by 5 

dBA or more at the nearest property line or a noise audible at 200 feet is defined as unnecessary, 

excessive, or offensive noise.

It is unlawful to operate equipment in any residential neighborhood that would exceed 50 dBA 

between 8 p.m. and 7 a.m. or exceed 55 dBA between 7 a.m. and 8 p.m.

plume and drift 

abatement technologies may be developed for a universe of facilities potentially subject 

This memo 

and presents 

close to residential and commercial areas,

to residential areas, local

For a conventional 

can be expected at a 

an important factor, as 

thumb is that at 

the noise level will dissipate roughly 3 

distance, and at distances greater than half the tower length, 

for each doubling of the distance. Based on 

from the 

As an example, a study conducted for the Manchester Street Station (CH2MHill 2009) indicated that the 

109 of the City of Providence, Rhode Island Municipal 

fic maximum noise levels, a noise level that exceeds the ambient noise by 5 

dBA or more at the nearest property line or a noise audible at 200 feet is defined as unnecessary, 

tial neighborhood that would exceed 50 dBA 
- 2 -

unmodified conventional tower described above (60 dBA at 500 ft) to meet a noise limit 

of 50 dBA.

Cooling tower noise consists of two components: one is the sound of the fans and fan 

drives, and the other is the sound of the water splashing down through the tower. Noise 

abatement technologies used primarily for reducing fan noise may include:

 Low noise fans and gear boxes

 Fan deck barriers

 Inlet and outlet attenuation

 Building a larger tower to allow use of smaller Hp fans and/or reduced fan tip 

speed2

 Cooling tower designs that do not use fans (e.g., natural draft towers).

Noise abatement technologies used primarily for reducing water splashing noise include:

 Sound walls

 Splash attenuation

 Inlet attenuation.

Various combinations of these technologies may be selected, depending on the site 

conditions, equipment design, noise reduction requirements, and economic 

considerations. 

Table 1 presents estimates using the rule-of-thumb for distances of 150, 350, and 500 ft, 

and 1,000 ft for a conventional mechanical draft cooling tower, a moderate reduction 

design (-10 dBA) and an aggressive noise abatement design (-16 dBA). 

Table 1. Rough Estimate of Noise Levels at Varying Distances For Cooling Towers 

With and Without Noise Abatement Technology

Receptor 

Distance

Conventional 

Design 

Moderate Noise 

Abatement 

(- 10 dBA)

Aggressive Noise 

Abatement Design

(–16 dBA)

Ft dBA dBA dBA

1,600 a50 40 34

1,000 a54 44 38

500 60 50 44

350 a65 55 49

150 a71 61 55

a Estimated values based on rule-of-thumb.

 

2 Reducing the fan tip speed is a simple way to reduce fan noise. Fan tip speeds “over 61m/s are 

considered high by most people. 51-61 is considered typical and expected. 41-51 would be considered low

noise. Below 41 is difficult to hear above the water noise.” (Marley 2010)
- 3 -

The data in Table 1 estimating the noise reduction attainable and distances are intended 

for illustrative purposes only. The determination of the degree of noise reduction 

required, if any, must be based on site-specific data and may vary greatly from site to 

site. In practice, noise abatement requires a sophisticated analysis by a specialist. A 

more detailed analysis using the octave band analysis and the proposed tower design, 

location, noise receptor locations, and consideration of nearby buildings and topography 

would need to be performed to obtain a more definitive answer regarding necessary tower 

design requirements.

Estimated Costs

EPRI’s cost estimation tool for cooling towers does not include costs for noise abatement. 

An example design provided by a cooling tower vendor indicated that reducing the noise 

level by 10 dBA from 60 to 50 dBA at 500 ft could increase the tower costs by

approximately 60% (SPX 2010b). In this case, the design included a reduction in the fan 

speed requiring a physically larger tower, an added fan deck, perimeter barrier walls, and 

splash attenuation. If greater reduction is required, the cooling tower vendor cited a 

design that reduced noise by 16.3 dBA at a distance of 500 ft that would increase costs of 

the cooling tower by nearly 100% (SPX 2010a).

By comparison, the 2001 316(b) Phase I technical documentation (“Economic and 

Engineering Analyses of the Proposed §316(b) New Facility Rule” Table A-4) provided

relative cost factors for various cooling tower types and indicated that the addition of 10 

dBA noise abatement should increase cooling tower capital costs by a factor of 30% and 

O&M costs by a factor of 7% when compared to a standard mechanical draft cooling 

tower. Using these data points as bounding estimates, the noise abatement tower capital 

cost factors can range from 30% to 60% to 100% represent a range of noise reduction and 

abatement technology combinations.

The amount of noise abatement required is a function of both the local community noise 

code and the distance from the tower to the nearest sound receptor that must meet the 

specified noise code. Noise abatement costs will be highest if a tower must be located 

near areas with highly restrictive noise codes, such as residential areas. The location and 

orientation of the receptors surrounding the tower are also important, as some noise 

abatement technology components may be needed only on one side of the tower, which 

can help reduce costs.

As noted above, noise abatement costs may range from 30-100% of cooling tower capital 

costs. The median tower component cost (including the basins) of a closed-cycle system 

retrofit is estimated by EPA to be approximately $80/gpm of recirculating cooling water 

flow (SAIC 2010). Based on the 30% and 60% factors, the added costs for a 10 dBA

noise abatement design can range from $24/gpm to $48/gpm. These differences 

represent different noise abatement strategies, with the higher cost example relying on 

larger towers and lower fan speeds, which should reduce the operating costs when 

compared to the lower cost approach which cited a 7% increase in O&M including the 

fan energy component. Since these costs are based on well-known design principles, the 
- 4 -

higher capital, lower O&M cost example has been selected as the best choice for 

estimating noise abatement costs in the proposed approach outlined below. While the 

larger tower may require a minor increase in the cost of materials maintenance, the 

reduced air velocities and reduce fan tip speed in the larger tower should reduce fan 

energy and fan maintenance requirements. Thus, the net effect of this noise abatement 

technology design on cooling tower O&M costs is expected to be minimal.

Plume Abatement

Background

Cooling towers dissipate heat via evaporation, resulting in warm, humid air being 

discharged from the towers. Under certain conditions, the plume is visible and may

persist for some time or distance. In some cases, this may be a concern for visibility on 

roads or at airports, icing of roadways or other structures (as the plume condenses), or for 

aesthetics.

Plume abatement can be accomplished by various means and is often accomplished using 

a hybrid wet/dry cooling tower that combines air from both dry cooling and wet cooling 

to produce a less saturated tower exhaust air stream. 

Estimated Costs

EPRI’s cost estimation tool for cooling towers does not include costs for plume 

abatement. For plume abatement technology, the total cost of the tower component is 

estimated to increase by a factor of 2.0-3.5.

3

 For this discussion of proposed changes to 

the cost methodology, a factor of 2.5 was selected for estimating the cost of conventional 

cooling towers with plume abatement, resulting in an additional cost of 1.5 times 

$80/gpm which is equal to $120/gpm.

Hybrid cooling towers will have higher O&M costs for the energy requirements and 

equipment maintenance compared to conventional mechanical draft cooling towers. A 

cooling tower vendor estimated that the pumping head would increases by 8 ft and the 

fan energy requirement would increase by 10% (SPX 2010a). This results in an increase 

in the EPA estimate for cooling tower energy requirement of 0.0000031 MW/gpm. It

was also estimated that the non-energy O&M cost would increase by 50% to 100% due to 

the larger tower and maintenance of coils and dampers (SPX 2010a). A factor of 80%,

which is close to the midpoint of the range cited and equal to an increase of $1.00/gpm,

was assumed for the increase in non-energy O&M for plume abatement towers. 

 

3 A cooling tower vendor cited 2.5 to 3.5 (SPX 2010a) as cost factors. The 316(b) Phase I support 

document (Table A-4) indicates that typical hybrid towers have capital cost factors of 2.5 to 3.0 when 

compared to standard cooling towers made of Douglas fir. Similarly, the EPRI Cooing Tower Calculation 

documentation states that plume abatement capital costs will be 2 to 3 times those of conventional 

mechanical draft towers.
- 5 -

Space Requirements

Conventional mechanical draft hybrid wet/dry plume abatement towers must be 

configured in an in-line configuration. For large volumes of cooling water, this requires a 

series of long towers that require an area that is long enough for the towers and wide 

enough to allow for spacing if two towers are set side by side. If the towers are placed 

too close together, plume recirculation can occur and significantly reduce tower 

performance. Potential solutions include a new design by SPX called ClearSky Air2Air,

which provides plume abatement and can be configured in the back-to-back 

configuration, and round towers which are described in more detail below. 

In a recent cooling tower retrofit study for Units 2 and 3 at the Indian Point Nuclear 

Power Plant, a more compact round tower configuration was the selected technology. 

The tower design included a round counterflow forced draft configuration, hybrid wet/dry

plume abatement with low noise fans, and sound attenuation baffles. These more 

expensive round hybrid towers were selected over conventional mechanical draft towers 

due to space limitations at the site which required a more compact design. The vendor’s

design-and-construct estimate4for these round hybrid cooling towers was $205 Million 

(2009 dollars) for a 702,000 gpm tower (Enercon 2010). This is equal to a tower unit 

cost of $292/gpm or roughly 3.65 times the estimated conventional tower cost of 

$80/gpm. These higher cost towers are representative of the cost of plume abatement, 

noise abatement, and compact size requirements combined, and are within the range cited 

above for plume abated towers considering they include noise abatement as well.

Application to Proposed Rule Costing Methodology

Table 2 provides a summary of the increase in cooling tower costs for the options

described above and the estimated total costs when they are applied to the “average” 

retrofit cost estimation factors used by EPA for conventional mechanical draft cooling 

towers. The “difficult” retrofit costs are also shown for comparison. EPA has selected 

the “average” difficulty retrofit cost factors as ones that take into consideration the range 

of variations in site-specific conditions that affect the degree of difficulty in retrofitting to 

closed-cycle cooling. Some facility retrofits will cost more and some less, but on a 

national basis these costs should balance out. 

The EPRI costs are based on a cooling tower retrofit cost analysis prepared by

Maulbetsch Consulting for approximately 50 facilities, which categorized cooling tower 

retrofits into “easy,” “average,” and “difficult” cost categories. Data presented by

Maulbetsch indicates that noise and plume abatement technologies are used for some of 

the plant costs (Maulbetsch 2003, Maulbetsch 2008). Thus, it is reasonable to assume 

that some noise and plume abatement technologies may be included as part of the 

technology mix associated with the Maulbetsch cost estimates used to derive these costs, 

particularly those that fall toward the “difficult” end of the range of costs. However, if 

requirements for cooling tower retrofits are more widely and strictly applied (i.e., noise or 

 

4 Enercon’s analysis is based on a recent estimate for the Calvert Cliffs Nuclear Plant, which also uses 

brackish water
- 6 -

plume abatement is more prevalent), particularly in high density population areas, the 

proportion of retrofits near the “difficult” end of the cost range may be greater than the 

mix in the Maulbetsch study cost database.

Table 2. Summary of EPA Cooling Tower Costs Plus the Added Costs of Noise and 

Plume Abatement

Capital Cost 

(2009 Dollars)

Fixed O&M 

(2009 Dollars)

Variable 

O&M –

Chemicals1

(2009 

Dollars)

Variable 

O&M -

Pump & Fan 

Power

Dollars/gpm

(% Increase2)

Dollars/gpm Dollars/gpm MW/gpm

Average Retrofit3$263 (0%) $1.265 $1.25 0.0000237

Difficult Retrofit3$411 (56%) $1.265 $1.25 0.0000237

Add for Noise 

Abatement $48 $0 0.0 0.0

Add for Plume 

Abatement $120 $1.0 0.0 0.0000031

Add for Round Plume 

and Noise Abatement4 $212 $1.0 0.0 0.0000031

Average with Noise 

Abatement $311 (18%) $1.265 $1.25 0.0000237

Average with Plume 

Abatement $383 (47%) $2.265 $1.25 0.0000268

Average with Both 

Plume and Noise 

Abatement

$431 (64%) $2.265 $1.25 0.0000268

Average with Plume 

and Noise Abatement 

with Space 

Limitations – Round4

$475 (81%) $2.265 $1.25 0.0000268

1 Non-power variable O&M costs are for additional treatment chemical for optimized 

tower operation at higher cycles of concentration.

2 Percent increase compared to “average” difficulty retrofit.

3 Values shown are same as used in previous cost estimates except that the previous fixed 

O&M total is now split into variable O&M for Chemicals and Fixed O&M.

4 Based on round tower with plume and noise abatement. 

Noise abatement may be necessary at locations near residential, urban, or other areas. 

However, it is difficult to determine (on a national scale) which facilities would incur 

noise abatement costs using the current set of information. Noise ordinances are typically 

administered at the state or even local level and would require a site-specific analysis to 

determine if they would be applicable at a given facility.
- 7 -

Plume abatement will primarily be a concern in locations where the plume may create 

safety problems such as reduced visibility on nearby roadways or icing on roads and 

bridges. Thus, facilities located near major roadways and bridges will be candidates for 

this requirement. As with noise abatement, it is difficult to determine (on a national 

scale) which facilities meet this criterion using the current set of information.

The availability of space and whether conventional or round towers would be feasible 

will be very site-specific and must take into consideration property size, shape, adjacent 

development, and topography. Requirements for the demolition and/or moving of 

existing structures and infrastructure may be more likely to be a requirement at sites with 

space constraints. Facilities that are located close to areas of higher population density

are more likely to have limitations on availability of space, since available space not 

currently used by the plant and adjacent property will tend to be developed. 

A detailed evaluation of each site would be required to determine which requirements 

would apply to that site. One possible source of data that may be used to identify

facilities that may be candidates for some combination of these requirements would be to 

use census data to identify facilities that are located within areas of higher population 

density.

As can be seen in Table 2, the selected retrofits for noise abatement, plume abatement, 

and both noise and plume abatement increase the estimated costs of an “average” retrofit 

by 18%, 46%, and 64%, respectively. If space constraints require a round tower that 

includes plume and noise abatement, the increase may be up to 81% using the 

assumptions in this analysis. By comparison, the “difficult” retrofit represents an 

increase of 56% and falls in the middle of this range of options.

There are two basic approaches that could be used to identify facilities that would be 

assigned higher costs for the proposed rulemaking, using surrogate data or using an 

alternative wet cooling tower design; these are described below.

Using Surrogate Data

Facility data necessary to determine specific tower requirements is not readily available 

and it may not be practical to apply the noise abatement, plume abatement, or round

tower costs shown in Table 2 to plants individually. A simpler solution would be to 

identify candidate facilities that may be more likely to require some mix of these

technology modifications using a surrogate measure such as local population density

data.5 Aggregate cost factors representing one or combinations of these requirements 

could then be applied. 

 

5 The U.S. Census Bureau defines an urban area as: "Core census block groups or blocks that have a 

population density of at least 1,000 people per square mile (386 per square kilometer or 1.6 per acre) and 

surrounding census blocks that have an overall density of at least 500 people per square mile (193 per 

square kilometer or 0.8 per acre)" (US Census Bureau 2000). A review of the population density and aerial 

views of several sample facilities may help in establishing reasonable threshold values for high and low

density areas. 
- 8 -

One approach would be to assume that the “difficult” retrofit capital costs ($411/gpm) or 

the combined plume/noise abatement costs ($431/gpm) would be representative of the 

costs of requiring some combination of noise and plume abatement at facilities that 

would otherwise require an “average” difficulty retrofit. For all of these facilities, the 

increased O&M costs associated with plume abatement in Table 2 should also apply. 

Alternative Wet Cooling Tower Design

A second approach would be to assume that facilities would install an alternative wet 

cooling tower design. The model wet cooling tower technology that forms the basis for 

the EPA compliance technology is the rectangular mechanical draft cooling tower 

configured either in an in-line or back-to-back configuration. For these types of cooling 

towers, the most common type of plume abatement technology involves use of separate 

dry (coils) and wet cooling sections with the exhaust of each being mixed prior to 

discharge. 

Back-to-back configuration is not advised due to poor mixing that occurs because the dry

section air is introduced on only one side. This limits the use of this technology to 

locations where the available space is compatible with in-line mechanical draft towers.

Other wet cooling tower technologies that provide plume abatement but have different 

space requirements are described below. 

SPX ClearSky

A new design by SPX called ClearSky Air2Air provides plume abatement and can be 

configured in the back-to-back configuration. This design places the dry cooling 

component directly above the wet component of the tower rather than along the side, thus 

allowing for a back-to-back configuration. This technology re-condenses a portion of the 

evaporated water and was designed to provide for water conservation, but was found to 

reduce plume visibility as well. It is a promising technology, especially with respect to 

reducing water consumption. The technology has only been demonstrated on a full-scale 

basis at a single location in New Mexico and remains a somewhat unproven technology

and may require time to develop acceptance within the industry.

Natural Draft Cooling Towers

Natural draft cooling towers (NDCTs) have higher capital costs and lower O&M costs 

than conventional mechanical draft towers. The lower O&M costs are due to the 

elimination of fan energy costs. At locations where there are no noise or plume 

abatement requirements, NDCTs are more economical than conventional mechanical 

draft cooling towers only for large base-load plants with a service life of 40 or more years

(SPX 2010b). 

NDCTs are suitable alternatives for plume abatement because the high air outlet location 

and large size of the plume reduces the possibility that the plume will approach the 
- 9 -

ground or be recirculated. When equipped with sound barrier walls, NDCTs also serve as 

an effective noise abatement technology option. At locations where both plume and 

noise abatement is required, the economic benefits of NDCTs become more favorable—

even more so if the cost of constructing a new flue gas stack associated with new air 

pollution control equipment is avoided by disposing treated flue gas through the tower.

6

However, as noted above, noise and plume abatement requirements are often the result of 

proximity to urban or residential areas where there may be building height restrictions 

and/or substantial public resistance to the installation of such large structures, potentially

limiting the applicability of this technology.

Hybrid Round Forced Draft Cooling Towers 

Round mechanical draft cooling towers function in a similar way to conventional towers,

with the air entering radially from all sides. Fans may be clustered around the center 

point of the tower (induced draft) or at the perimeter openings (forced draft). The latter is 

commonly used for hybrid round plume abatement towers. These towers have the 

following advantages:

 Useful where available space is compact and site does not allow for the long 

narrow configuration of mechanical draft towers.

 While the air outlet is closer to the ground than natural draft towers, the large 

diameter and compact nature of the combined plume increases plume height over 

conventional mechanical draft towers, reducing plume recirculation and 

eliminating spacing concerns associated with conventional towers.

 Increased plume height improves the distribution of drift, making this technology

useful where better dispersion of saltwater drift is desired.

In one example cited above, the estimated cost of round plume and noise abatement 

towers was about $44/gpm higher than the estimated cost for combined plume and noise 

abatement rectangular mechanical draft towers.

Fan Assisted Natural Draft Cooling Towers

Fan assisted natural draft cooling towers are a hybrid of mechanical draft and natural 

draft towers and are similar in design to NDCTs but have a much lower height and use 

fans during periods when conditions require them. These towers have the following 

advantages:

 Useful where space requirement is compact and site does not allow for the long 

narrow configuration of mechanical draft towers.

 Tower height is limited.

 Lower fan energy requirement than mechanical draft towers.

 

6

See detailed discussion in DCN 10-6681.
- 10 -

 Suitable for locations where climatic conditions would result in insufficient 

buoyant forces in an NDCT, requiring fan assist to provide sufficient airflow. In 

this case, the cost of the added height of NDCT is not justified.

These towers do not provide for plume abatement, but like NDCTs, they have a higher 

discharge location and the plume is larger and more buoyant, making it less prone to 

approach the ground or recirculate compared to conventional mechanical draft towers.

Drift Abatement

Background

The cooling tower engineering cost estimates use the EPRI cost spreadsheet methodology

for the capital costs for “average” or “difficult” installation. The Spreadsheet Instructions 

accompanying the EPRI Tower Calculation Worksheet state: “Most modern cooling 

towers are equipped with drift eliminators which are specified to limit drift to 0.0005% of 

the circulating water flow.” Since the EPRI costs are for modern cooling towers and the 

default drift rate in the spreadsheet is 0.0005%, EPA can reasonably assume that the 

compliance cost estimates include costs for drift eliminators. 

For comparison, cooling towers that do not employ drift eliminators emit significantly

more water droplets. Table 3 below illustrates typical drift rates for towers with and 

without drift abatement.

Table 3. Cooling Tower Drift Factors

Tower Type Drift Estimation Factor*

Natural Draft 0.3 to 1.0%

Mechanical Draft 0.1 to 0.3%

Tower with Drift Eliminator 0.005%

Tower with High Efficiency Drift 

Eliminator

0.0005%

* Drift (gpm) = Recirculation (gpm) x Drift Estimation Factor / 100

Note that while the EPRI methodology assumes high efficiency drift eliminators, no data 

has been collected on the prevalence of standard drift eliminators versus high efficiency

drift eliminators in use at existing facilities or at recently constructed towers. However, 

in addition to the EPRI documentation, BPJ suggests that new towers would likely use 

the high efficiency eliminators, as the additional costs of installing and operating them 

can be included in the initial cooling system design and the incremental costs over 

standard efficiency would be small. Additionally, air quality requirements at a given site 

may require high efficiency eliminators as part of Best Available Technology.

Estimated Costs

As noted above, costs for high-efficiency drift abatement are already included in the costs 

calculated by the EPRI cost tool. No further action is required.
- 11 -

Conclusion

Noise, plume and drift abatement technologies can add significant costs to a cooling 

tower retrofit design. A number of site-specific factors come into play to determine the 

selection of technology, but appropriate assumptions for estimating national-level 

compliance costs can be made regarding the impacts of these abatement technologies to 

the overall cost of the retrofit.
- 12 -

References

CH2MHill. Response to Request for Information to Supplement RIPDES Permit

Application - Manchester Street Station (RIPDES Permit No. RI0000434). August 2009

Enercon Services, Inc. Engineering Feasibility and Cost of Conversion of Indian Point 

Units 2 and 3 to a Closed-loop Condenser Cooling Water Configuration. February 12, 

2010.

Marley NC® Fiberglass Cooling Tower. Engineering Data & Specifications. 2010

http://spxcooling.com/pdf/uk_NCF-TS-10.pdf

Maulbetsch, J. S. Issues Associated with Retrofitting Coastal Power Plants. Oncethrough Cooling: Results Symposium. University of California. Davis, California.

January 16, 2008

SAIC. John Sunda. Memo RE: “Estimation of Net Difference in Capital and O&M Costs 

for Once-through Versus Closed Cycle Cooling for New Generating Units at Existing 

Power Plants and for Repowering of Existing Generating Units” March 5, 2010

SPX Inc. Kent A. Martens, P. E., Chief Technical Advisor - Evaporative Cooling. 

Telephone Contact report with John Sunda, SAIC. January 15, 2010a

SPX Inc. Kent A. Martens, P. E., Chief Technical Advisor - Evaporative Cooling. 

Telephone Contact report with John Sunda, SAIC. February 26, 2010b

SPX Inc. Kent A. Martens, P. E., Chief Technical Advisor - Evaporative Cooling. 

Personal Communication. Email to John Sunda, SAIC. January 27, 2010b

US Census Bureau. Census 2000 Urban and Rural Classification. 2000 

http://www.census.gov/geo/www/ua/ua_2k.html