Tetra Tech, Inc.

10306 Eaton Place, Suite 340 Fairfax, VA 22030 phone 703 - 385 - 6000 fax 703 - 385 - 6007 TO : Paul Shriner , EPA FROM : Kelly

Meadows DATE: Ju ly

30 , 2010 SUBJECT: Estimatin g the number

noise or plume abatement and EPA requested that Tetra Tech develop that may need to be considered for increased facility rule due to noise or plume abatement for installing cooling towers as a anal ys is and rationale for the estimated universe of affected facilities. concluded that about one in four addressed by

the p roposed 316(b) these technical factors; EPA has account for additional technologies or other mitigation activities at these facilities Appr oach To comply

with a potential requirement for flow reduction, s choose to install cooling towers to conditions or at certain locations, the installation of cooling towers can lead to non aquatic impacts such as plumes or noise. Facilities located in densel y populated areas or on small sites may

also have di towers. In the majority o f cases, these technical issues do not ultimately affect the feasibility of constructing the cooling tower , but they do affect the cost. The anal ys is below reflects EP

A’ s ass umptions in estimating the number of facilities that may

1 See chapter 8 of the Technical Development Document. Instead of estimating which model facilities wo uld require increased costs, EPA applied a cost increase to all exiting facilities. 2 In fact, EPA’s costs reflect the assumption that all facilities subj will install cooling towers. 

### MEMORANDUM

10306 Eaton Place, Suite 340

, EPA Kelly Meadows and Christine Wong g the number of potential facilities with increased costs due to noise or plume abatement and space constraints Tetra Tech develop an analy sis to estimate the universe of facilities need to be considered for increased costs of compliance with the 316(b) noise or plume abatement requirements, as well as space constraints cooling towers as a compliance response . This memo documents anal ys is and rationale for the estimated universe of affected facilities. Tetra Tech has concluded that about one in four ( 25 percent ) of the overall universe of facilities

roposed 316(b) existing facility rul e may be affected b y one or more of these technical factors; EPA has increased its estimate of compliance costs accordingl y to account for additional technologies or other mitigation activities at these facilities

To comply

with a potential requirement for flow reduction, s ome facilities are likel y to choose to install cooling towers to comply with this requirement. 2 Under certain conditions or at certain locations, the installation of cooling towers can lead to non aquatic impacts such as plumes or noise. Facilities located in densel y populated areas or on small sites may

also have di ffi culty identifying suf ficient space to construct the towers. In the majority o f cases, these technical issues do not ultimately affect the feasibility of constructing the cooling tower , but they do affect the cost. The anal ys is umptions in estimating the number of facilities that may See chapter 8 of the Technical Development Document. Instead of estimating which model facilities wo uld require increased costs, EPA applied a cost increase to all exiting facilities. In fact, EPA’s costs reflect the assumption that all facilities subj ect to the flow reduction requirements

1 with increased costs due to
estimate the universe of facilities

316(b) existing requirements, as well as space constraints ,

This memo documents the

Tetra Tech has of the overall universe of facilities one or more of accordingl y to account for additional technologies or other mitigation activities at these facilities

. 1

ome facilities are likel y to Under certain conditions or at certain locations, the installation of cooling towers can lead to non

aquatic impacts such as plumes or noise. Facilities located in densel y populated areas or suf ficient space to construct the towers. In the majority o f cases, these technical issues do not ultimately affect the feasibility of constructing the cooling tower , but they do affect the cost. The anal ys is umptions in estimating the number of facilities that may See chapter 8 of the Technical Development Document. Instead of estimating which model facilities ect to the flow reduction requirements2

encounter these dif

ficulties and establishes an approach for increasing the cost estimates accordingl y. Natural draft or mechanical draft cooling towers can produce a plume. Plumes (comprised large ly

of water vapor) can create problems with fogging and icing, which have been recorded to create dangerous conditions for local roads and for air and water navigation , as well as cause aesthetic impacts

. To estimate the number of facilities that would likely

be subject to plume abatement requirements, T etra Te ch used two indicator s as a prox y for potential impacts: proximity to airports and proximity to major roads

. Te tra Tech selected a 2

- mile radius from airports and a 0.5

- mile radius from major roads as the distance threshold s for facilities likely to require plume abatement. EP A had previously mapped the prevalence of cooling towers and their proxi mity to highway s, navigable rivers and lakes, and railway s , and defined those f acilities that were within several hundred meters from those ty pes of areas as being in “close proximity .” 3 Te tra Te ch selected a 2

- mile radius from airports as a proximity threshold to include this earlier definition of “ close proximity , ” plus a generous safety

margin for aviation safety

. Te tra Te ch selected the 0.5

- mile radius from major roads as a proximity threshold to account for the distance required to disperse fog or ice

- forming plumes, plus a generous safet y margin. 4 Noise from mechanical draft cooling towers is generated b y falling water inside the towers , plus fan or motor noise . Noise from power plant sites generally do not result in of f

- site levels more than 10 decibels (dB) above background levels. 5 Facilities that make use of cooling towe rs, however, might expect the ty pical noise level to be approximately 70 dB within 50 feet of the tower
. 6 Because sound levels diminish approximately 5 dB per doubling of distance , and 55 dB falls between the sound level of rainfall and normal conversatio n 7 (and therefore would not be considered noise pollution), a buffer of 400 feet would suffice for noise abatement at most sites. 8 Inaddition, EPA’s “Protective Noise Levels” guidance found that ambient noise levels of 55 dB was sufficient to protect pub lic health and welfare and, in most cases, did not create an anno yance. 9 As for noise pollution at the site itself, the New York State Department of Environmental

3 Te chnical Development Document for the Proposed Section 316(b) Phase II Existing Facilities Rule , Chapter 6, Non

- Water Quality Impacts, p. 6

- 7. 4 The documentation from the NPDES permit renewal for Brayton Point was also considered (see http://www.epa.gov/ne/braytonpoint/index.html ). In this case, the facility cited a proximity to highways and bridges as potential challenges to retrofitting to closed

- cycle cooling. Using online aerial photos, the distance to the nearest major road is approximately 0.5 mile and the bridge is approximately 1.0 mile away. Dominion Energy ultimately concluded that a natural draft cooling tower was the best choice for its closed

cy cle cooling system; while Dominion has not publicly stated its rationale, it can be assumed that abatement of the cooling tower plume was at least one factor. 5 US EPA. 2002. Te chnical Development Document for the Proposed Section 316(b) Phase II Existing Facilities Rule , Chapter 6, Non

- Wa ter Quality Impacts, p. 6

- 9. 6 SPX. 2009. Cooling Tow er Fundamentals, p 75. 7 American Speech

- Language

- Hearing Association. Noise and Hearing Loss . Accessed at http://www.asha.org/public/hearing/disorders/noise.htm on August 1 , 2010. 8 Noise levels wo uld be as follow s: 70 dB at 50 feet, 65 dB at 100 feet, 60 dB at 200 feet, and 55 dB at 400 feet. 9 EPA 550/9

- 79

- 100, November 1978.3

Conservation’s “Assessing and Mitigat ing Noise Impacts” policy states that 60

- 70 dB is the b eginning of the threshold for anno yan ce in non

- industrial sites and that noise can exceed 65 dB (and up to 79 dB) in commercial or industrial sites. A common goal is to keep new noise sources from increasing the overall noise levels by 5

- 10 dB. Given that noise is measured on a logarithmic scale, adding a cooling tower that operates with a sound level of approximately 70 dB will be unlikely to add a significant level of noise to an alread y noisy industrial site. 10 Given that noise appears to dissipate relatively quickl y (and the fact that man y i ndustrial sites are large and a 400 foot buffer would not be a significant limitation), effects from noise are not expected to be significant at most sites. There will certainl y be some sites that require noise mitigation, but the number of sites is likely to already

be represented by

the anal ys es for plume and population density

. Te tra Tech decided to use population density as a proxy

indicator of facilities that might be subject to land or space constraints fo r installing cooling towers. Tetra Tech conducted a geographic information sy stems (GI S) anal ys is of various U.S. Census (2007 figures) data to determine the point at which population blocks (blockgroups) indicate the transition from more densely develope d urbanized areas to areas with ample space for development. 11 After comparing several urban areas as examples , a threshold of 1000 persons per square mile was selected as the approximate transition point. The figures below show areas color

- coded and labe led according to Census population density (2007 figures). For this anal ys is, a facilit y was considered to be development restricted if the facility was located within a blockgroup where population density was greater than or equal to 1000 persons per squ are mile. Washington DC and Buffalo , New York were examined to estimate the selected threshold and the graphics are presented below. Topeka, Kansas and Salinas , California were also examined but are not presented below

.

10 NYDEC. 2000. Assessing and Mitigating Noise Impacts , p. 14. 11 Tetra Tech also considered an analysis using the Census Urban Areas layer, but chose to use blockgroups instead because they allowed for the identification of low

- density blockgroups within the urban area boundary.4

Population Density

for Washington, DC5

Population Density

for Buffalo, N Y6

For the purpose of this analy sis, facilities located within a blockgroup with a density greater than 1000 persons per square mile are considered to be potentiall y subject to space constraints for installing cooling towers. Because proximity

to airports, major roads, and densely populated areas may be correlated with the need for facilities to install technologies to mitigate those effects , the proximity anal ys es for all these of these factors are expected to complement one another

. In other words, each of these technical challenges relate to a pro ximity to other uses of surrounding areas (e.g., roads, residential, etc.); as a result, it is reasonable to expect that separate anal ys es for each challenge would identify some of the same facilities. Ana lysis Te tra Tech plotted the longitudinal and lat itudinal coordinate locations of the model power plant facilities used to develop compliance costs

. Te tra Tech then plotted GI S lay ers to determine if facilities 1) fall within a 2

- mile radius from all airports; 2) intersect the 0.5

- mile radius from all m ajor roadway s (defined as a limited access road or highway); and 3) are located within a blockgroup with 2007 po pulation density per sq mile ≥ 1 , 000 ( FacilPopDens1000 ) . The results are shown in the map below

.78

Results Tetra Tech further refined the anal ys is with four additional steps. First, the universe (initially comprised of 891 facilities, including all power plants and manufacturers that completed a technical questionnaire) was limited to facilities with a design intake flow (DIF) of greater than 125 million gallons per day (MGD). 12 Second, facilities that did not complete a detailed questionnaire were removed, as costs for these facilities will not be developed in the proposed rule. 13 Third, manufacturers were rem oved from the anal ys is, as these sites are alread y assigned “difficult” level costs in the EPRIcost methodology

. Fourth , statistical survey

weights were added to properly adjust the repre sentativeness of each facility

. Out of the 224 detailed questionnaire facilities (250 weighted) with a DIF greater than 125 MGD, the anal ys es showed that: 1) 50 (56 weighted) of these 224 are within 0.5 mi les of a major road. o 1 of these was within 2 miles of airports. o 12 of these are in high population density areas as defined b y FacilPopDens1000.
 Of these 12 , none are within 2 miles of airports. 2) 4 (4 weighted) of these 224 are within 2 mi les of an airport. o 1 of these was within 0.5 miles of a major road. o None of these are within high population density areas. 3) 25 (28 weighted) of these 224 are within a high population density area. o None of these are within 2 miles of an airport. o 12 of these are within 0.5 miles of a major road. As such, a total of 66 (29.4 % ) facilities (74 weighted or 29.6%) of the universe of facilities with a DIF >125 MGD facilities are subject to at least one constraint. Given the conservative nature of this analy sis, 14 rounding the percentage of facilities that may require additional costs for abatement technologies or face chall enges due to space constraints to 25% was deemed appropriate. By comparison, Electric Power Research Institute (EPRI ) conducted a survey of its members and found that approximately 23 percent of respondents answered that they

12 Lo wer flow facilities will require smaller cooling tow ers and be less likely to encounter issues with noise, plume, or space. Additionally, many low DIF facilities already employ closed

- cy cle coo ling 13 In other w ords, only model facilities for which costs are generated for the proposed rule were included. 14 For example, the analysis did not account for prevailing wind direction, w hich may eliminate some facilities from the likely area of effect. In another example, noise abatement costs are relatively low; assigning a “difficult” level cost to a facility that is only required to mitigate noise impacts would likely be an overestimate of the compliance costs.9

would be concerned space cons traints, should they be required to retrofit with cooling towers. 15 , 16 While this seems to be consistent with Tetra Tech’s anal ys es, over half of the facilities survey ed by

EPRI had not yet studied the impacts of installing closed

- cy cled recirculating s ys tems. In addition, EPA personnel have observed, during the course of site visits, situations in which space constrained facilities were able to creatively resolve technical issues

. 17 Additionally , b ased on EPA personnel best profes sional judgment, many facilities are conservative when estimating their required responses to potential regulations regarding cooling water intake structures. Furthermore, facilities that have not y et studied their site

- specific impacts from installing cl osed

- cy cle cooling may not take into account the innovative or creative solutions that can be developed, even for space - constrained areas. As a result, the assumptions underlying EPA’s analy sis are likely to be conservative and may overstate compliance co sts. Given the results of the GI S anal ys es and the best professional judgment of EPA personnel, as well as the safet y margins incorporated in the GIS anal ys es, Tetra Tech’s anal ys is supports a threshold of 25 percent of facilities that may be constraine d by cooling tower plume, noise, or space restrictions and should therefore be assigned an increased compliance cost.

15 Net Environmental and Social Effects of Retrofitting Power Plants with Once

- Through Cooling to Closed

- Cycle Cooling. EPRI, Palo Alto, CA: 2008. p4

- 59. 16 Forty six percent responded that there were local noise ordinances; there w as no indication of whether these ordinances would be restrictive to installing cooling towers. There w ere no questions regarding im pacts due to a cooling tower plume. 17 See, for example, the site visit report for McDonough Station.