1 Site Visit Report El Segundo Generating Station 301 Vista Del Mar El Segundo, CA 90245 September 1 , 2009 1.0 Background and Objectives The Environmental Protection Agency (EPA) is in the process of developing 316(b) cooling water intake structure requirements that reflect the best technology available (BTA) for minimizing adverse environmental impact for all existing power plants and manufacturing facilities. As part of this process, EPA staff is visiting electric generators and manufacturers to b etter understand the cooling water intake structure (CWI S) technologies in use at facilities, including the site

specific characteristics of each facility and how these affect the selection and performance of CWI S technologies. EPA is also visiting facili ties to better understand cooling water use and specific issues or technologies that can affect 316(b) compliance. EPA selected El Segundo Generating Station (El Segundo) for a site visit due to its ocean withdrawal location and to understand its repoweri ng project in relation to cooling water needs. 1

2.0 Facility Description El Segundo occupies approximately 22 acres of a 33 acre oceanside site in the City of El Segundo and began operations in the 1950s. The facilit y is located immediately

adjacent to Doc kw eiler and Manhattan State Beaches (to the west and north). Residential areas of the Cit y of Manhattan Beach adjoin the propert y’s southern boundary, while a portion of a refinery lies to the east. The area is fairl y hilly, with the facilit y’s switch yar d located at an elevation several dozen feet above the generating units. See Attachment B for an aerial view

. The facility is owned b y El Segundo Power (a subsidiary of NRG ) . The facility ’s NPDES permit ( CA0001147 ) expired May 10, 2005 and has been administratively extended pending renewal. 3.0 Electricity Generation and Transmission El Segundo currentl y operates 2 natural gas

- fired generating units (Units 3 and 4), which have a combined generating capacity of 670 MW

. These units began operation in 1964 and 1965, respectivel y. Units 1 and 2 were retired in 2002 and are being repowered. (See Section 8.0 for more information.) Units 3 and 4 have historically

had high capacity

utilization rates, but have dropped to approximately 10% in recent y ears.

1 EPA provided a draft of this report to El Segundo but did n ot receive any comments from the facility.2 The switch yard is owned by Southern California Edison. 4.0 Cooling Water System and Intake Structure The facility

currentl y operates one offshore CWI S. 2 The CWI S is comprised of a pipe located approximately 2600 feet offshore at a depth of 2 7 feet fitted with a velocity cap . Water is with drawn from Santa Monica Bay through the velocity cap (which is fitted with marine mammal exclusion bars) to a forebay onshore with a trash rack and 4 intake bay s with one coarse mesh (5/8”) traveling screen each. Screens are washed twice per day or as needed, based on the head differential across the screen. Materials and fish removed from the screens are disposed in the landfill. The design through

- screen velocity at the traveling screens is 2.0 feet per second (fps). The design intake flow (DIF) for El Segundo is 3 9 9 million gallons per day (mgd). El Segundo uses both biocides and heat treatment for biofouling control. Sodium hy pochlorite injection is used three times per day fo r 40 minutes each. Approximately

every 6 weeks, the facility

closes its discharge tunnel and recirculates the cooling water; it reaches approximately 125°F and serves to remove colonial organisms. The facility ’s discharge point is also offshore, at a dis tance of about 2100 feet. 5.0 Impingement and Entrainment Information El Segundo conducted impingement mortalit y and entrainment monitoring in 2006 and submitted a report to the state in January 2008. The sampling program included fish, invertebrates and crustaceans, and looked at various life stages of each. Two sampling stations recorded entrainment data, with ten additional station s serving as the source water control station s . In12 entrainment sampling events (collected samples every 6 hours in a 24 hour period) representing normal operations , 420 ,00 0 larvae (in 66 taxa) , 57 0 ,000 eggs , and 431 larval shellfish were collected. Impingement was recorded during 12 (one per month) events, plus an ad ditional 4 collections during heat treatments. During normal operations, 22 fish ( 9 species ) were collected, with no species being numericall y dominant. During heat treatments, 916 fish ( 45 species ) were collected. The total estimated annual impingement was 1527 fish. The study concluded that there is no adverse

2 For Units 3 and 4. The offshore CWIS for Units 1 and 2 is now retired, although the facility does continue to periodically operate one pump to move water through the intake and discharge tunnels to inhibit biof

ouling. Once repowering is complete, the intake tunnel for Units 1 and 2 w ill be sealed.3 environmental impact occurring as a result of the operation of the El Segundo facility

. 6.0 Cooling Tower Feasibility Facilit y representatives note d that El Segundo is located on a compact, urban site. As explained in Section 2.0, the facility is bordered by

city streets and state beaches on either side. Residential areas and an adjacent refinery also limit available space nearb y. El Segundo is also located approximately 2 miles away from L os An geles International Airport. Materials provided b y the facilit y estimated that a retrofit to wet or dry cooling would cost between $100

- 115 million. El Segundo, along with all other coastal once

- through cooling facilities in California, w a s recent evaluat ed by the State Water Resources Control Board as to the potential to retrofit the facility to closed

- cy cle cooling. A report 3 prepared for the California Ocean Protection Council (OPC) and State Water Board in 2008 identified several obstacl es that would likely influence the feasibility

of cooling towers at El Segundo: the compactness of the site, the likely need for plume abatement, and the proximity of residential areas . Because of these obstacles, the report concluded that a retrofit to closed

- cy cle cooling was not feasible at El Segundo. 7.0 Debris Handling Facilit y representatives did not identify an y significant problems with debris. 8.0 Repowering/Future Uses Units 1 and 2 will be demolished and the new Units 5 and 7 (combined cycle) built in their place. The new units will be more efficient and flexible than the retired units allowing the facility to better respond to peak and load

- based demand and have a combined generating capacit y of 560 MW. The original design for the new units called for a once - through cooling sy stem , but the facility amended its design to utilize a closed

- cy cle dry cooling s ys tem. Faci lity representatives noted that multiple factors influenced their decision to move towards dry coolin g: financing for dry

cooling was easier to obtain at the time of the design, they preferred the design over other tower designs , dry cooling would allow them to eliminate their NPDES permit, and dry cooling offered a greater degree of permitting certainty

. In particular, facility representatives noted that an ongoing legal battle over the availability of emission credits within the South Coast Air Quality Management District ha s raised the possibility that no new projects would be able to obtain the neces sary air permits , including facilities repowering with

3 California’s Coastal Pow er Plants: Alternative Cooling Systems Analysis4 wet cooling towers. 4 In selecting dry cooling , El Segundo is eliminating approximately

200 mgd of water withdrawals. 5 The repowering project is currentl y scheduled for completion in June 2011. Howev er, facility

representatives noted they are currentl y behind schedule for constructing the new units, as permitting delay s (related to air emissions permits) have caused delay s. Facilit y representatives stated that they are open to the concept of repowerin g Unit 3 and 4, but that no plans are currently being made. 9.0 Cooling Ponds There are no cooling ponds onsite. 10.0 Ownership El Segundo is owned b y NRG Energy , an investor

- owned compan y . 11.0 316(a) EPA did not collect any

information regarding El Segundo’s thermal discharge. 12.0 Ash Handling El Segundo does not use coal as a fuel and therefore has no ash ponds. 13.0 Air Emissions Controls EPA did not collect any

information regarding air emissions controls. 14.0 Additional Information Facilit y representatives stated that they had not reached a definitive response for complying with the now

- suspended 2004 Phase II rule. Facility representatives indicated they likely

would have pursued repowering, as retrofitting cooling towers to a faci lity

with a low utilization rate does not make sense.

4 The original cooling system was designed (and approved) to use once

- through cooling, but c oncerns about the long

- term

risks associated with such an approach were raised within the company. Specifically, uncertainty regarding future 316(b) requirements (i.e., the possibility that the newly repowered units w ould be required to retrofit a cooling tower) led NRG to adapt its design. With a dry cooling system, the repow ered units w ould be able to avoid many of the potential pitfalls that might accompany a retrofit w et cooling tower, such as additional permits that would need to be acquired. Facili ty representatives noted that a retrofit would likely have been mo re expensive, but did not conduct extensive studies on the im plications for financing and feasibility for the various cooling system configurations. To better guarantee the future stability of the generating units, NRG opted to install dry cooling with the repow ered units to avoid any potential future problems. 5 The estimated design flow for a once

- through cooling system for the new units is 200 mgd.5 Facilit y representatives noted that the L ong Beach power plant has also repowered and eliminated its once

- through cooling. The existing cooling sy stem had too many

leaks and was replaced with dry cool ing. Attachments Attachm ent A List of A ttendees Attachment B Aerial Photo s Attachment C PowerPoint presentation “El Segundo Power Redevelopment

Project” (September 1, 2009)6

Attachment A
-- List of Attendees Paul Shriner, EPA Jan Matuszko, EPA John Kemmerer, EPA Region IX Tim Havey , Tetra Tech Kelly Meadows, Tetra Tech George Piantka, NRG Alex Sanchez, NRG7

Attachment B
-- Aerial Photo Please see DCN 10

- 6552A accompanying this document. Attachment C

— PowerPoint presentation “El Segundo Power Redevelopment Project” (September 1, 2009) Please see DCN 10

- 6552B accompany ing this document.