**Tetra Tech, Inc.**

**10306 Eaton Place, Suite 340 Fairfax, VA 22030**  **phone 703**  **- 385**  **- 6000**  **fax 703**  **- 385**  **- 6007**  DATE: November 1, 2011 TO : Paul Shriner and Lisa Biddle, USEPA FROM : John Sunda and Kelly Meadows, Tetra Tech SUBJECT: Analy sis of Intake Through

Sy stem Intakes As a companion to other analys es on intake velocity, Tetra Tech was tasked with intake velocities at facilities utilizing closed Table 1 provides a summary of the distribution of the the detailed questionnaire (D Q ) for cost anal ys is and were classified as closed similar data for all intakes reported in both the DQ and short technical questionnaire (STQ) but is limited only

to facilities where the entire plant was classified as recirculating (i.e., does not include facilities classif

ied as combination, other velocity distributions.

**Distribution of Through**  **Power Generation Intakes Used in Costing Through**  **Velocity** >0.5 >1.0 >1.5
In cludes both retrofits and original CCRS 

### MEMORANDUM

November 1, 2011 Paul Shriner and Lisa Biddle, USEPA John Sunda and Kelly

Meadows, Tetra Tech of Intake Through
- screen Velocity at Existing Closed Cycle Cooling As a companion to other analys es on intake velocity, Tetra Tech was tasked with intake velocities at facilities utilizing closed
- cycle cooling s ys tems. the distribution of the through
- screen velocity data reported in ) for power generation facility intakes that were included in the cost anal ys is and were classified as closed
- cycle sy stems with co oling towers. Table 2 provides similar data for all intakes reported in both the DQ and short technical questionnaire (STQ) but is limited only

to facilities where the entire plant was classified as recirculating (i.e., does not

ied as combination, other , etc.). Both data sets result in similar screen

**Table 1 of Through**  **- screen Velocity for Closed Cycle**  **Power Generation Intakes Used in Costing Through**  **- screen**  **Velocity (fps)**  **Number**

**of Intakes Percent**  **of**

**Total** ≤0.5 25 42% >0.5
- ≤1.0 11 18% >1.0
- ≤1.5 9 15% >1.5
- ≤2.0 3 5% >2.0 12 20% Total 60 100% In cludes both retrofits and original CCRS

screen Velocity at Existing Closed Cycle Cooling As a companion to other analys es on intake velocity, Tetra Tech was tasked with analyzing the velocity data reported in power generation facility intakes that were included in the

Table 2 provides similar data for all intakes reported in both the DQ and short technical questionnaire (STQ) but is limited only

to facilities where the entire plant was classified as recirculating (i.e., does not etc.). Both data sets result in similar screen**Table 2 Distribution of Through**  **- screen Velocity for Closed Cycle**  **Power Generation Intakes f or**  **Both STQ and DQ Intakes Through**  **- screen**  **Velocity (fps)**  **Number**

**of Intakes Percent**  **of**

**Total** ≤0.5 47 45% >0.5
- 1 .0 23 22% >1.0
- 1.5 8 8% >1.5
- 2.0 7 7% >2.0 20 19% Total 105 10 0% In cludes both retrofits and original CCRS For comparison , Table 3 shows the distrib ution for all power generation intakes as reported in the TDD. **Table 3**

**Distribution of Design Through -**  **Screen Velocities For**  **All Power Generation Facilities Through**  **- screen**  **Velocity (fps) Estimated** 

**Number of CWISs**  **1 Percent of** 

**Total** ≤ 0.5 148 17% > 0.5

– 1 .0 200 22% >1.0
- 2 .0 316 35% >2 .0 162 26 % Total 893 100% 1 Weighted e stimate s Source: Exhibit 4
- 17 of TDD A comparison of Table s 1 and 2 to Table 3 indicates that a much larger portion of the subset of closed
- cycle intakes would be able to meet a 0.5 fps velocity standard
. The reduced intake flow volume of a closed
- cycle sy stem is likely to be a contributing factor to this trend
. The intakes in Tables 1 , 2, and 3 include both cooling water s ys tems originally built as closed cycle plus those that have been converted from once
- through to closed
- cycle cooling ( i.e., retrofits )
. To determine if there is any difference in the intake velocity distribution between those two groups , a review of readily available information of facilities with retrofits was performed. Currentl y , EPA has identified 10 facilities where closed
- cycle retrofits have occurred
. Post retrofit intake through
- screen velocity data was available fro m the technical survey s for those retrofits that occurred prior to the year 2000 and from site visit data for several of the more recent retrofits
. Table 4 identifies the retrofit plants , retrofit dates, and availability of screen velocity data. The Jeffries plant reported data for two intakes.**Table 4**  **Summary of Known Plants that have Performed a Closed Cycle Retrofit**  Plant State Retrofit Year Post Retrofit

Velocity Data Available Wateree SC 2006 No Nearman Creek KS 2006 No Brayt on Point MA Ongoing No Linden NJ 2002
- 2005 NA 1 Yates GA 2004 Yes 2 McDonough GA 2008 Yes 2 Canady s SC 1972&1975 Yes Jefferies SC 1985 Yes Jefferies SC 1985 Yes Pittsburg Unit 7 CA 1976 Yes Palisades MI 1974 Yes 1 Uses gray water as makeup source and no longer has an intake 2 In stalled 0.5 fps wedgewire screens. Table 5 summarizes the distribution of the through
- screen velocities for th e seven intakes at facilities where closed
- cy cle retrofits have occurred. 1 A comparison of the distributions in Table 5 to Tables 1 and 2 shows a similar proportion of intakes with through
- screen velocities ≤0.5
. The most noticeable difference is that no intakes in th e known retrofit sample had through
- screen velocities > 1.0 fps compared to 40% and 33% in the larger samples in Tables 1 and 2 that include both retrofits and original CCRS sy stems . **Table 5**  **Distribution of Through**  **- screen Velocity at Intakes Where**  **Closed Cycle Retrofits are Known**  **to Have Occurred Through**  **- screen**  **Velocity Number** 

**of Intakes Percent** 

**of Total** ≤0.5 3 43% >0.5
- ≤1.0 4 57% >1.0
- ≤1.5 0 0% >1.5 0 0% Total 7 100%

1 The “intake” for the Linden facility theoretically has a velocity of “0” since it no longer uses its intake , but was not included since reuse of gray water is not available to most facilities.Possible Followup Analysis

As seen in Table 5, two of the retrofit intakes were installed fairly recently and it’s possible the design requirements imposed may have been influenced by recent 316(b) regulatory developments. To help confirm these differences, it would be useful to attempt to identify additional intakes associated with closed
- cycle retrofits. The DQ survey includes questions regarding cooling towers that ask for the “Calendar Year Cooling Tower(s) Installed” on a per Cooling Water Sy stem (CWS) basis. Itshould be possible to identify oth er “pre
- ye ar 2000” closed
- cycle retrofits where through
- screen velocity data is available by combining this “year installed” data with EIA data regarding the ye ar(s) generating units came online for those plants with closed cycle s ys tems. While there may be some difficulty identifying which towers (or CWSs) are associated with each generating unit, for those where the generating units clearl y pre date the cooling towers , the likelihood that a retrofit occurred will be high
.