Document ID: EPA-HQ-OW-2008-0667-0595
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2011-04-20T04:00Z

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 better understand the cooling water intake structure (CWIS) technologies in use at facilities, including the site-specific characteristics of each facility and how these affect the selection and performance of CWIS technologies.  EPA is also visiting facilities 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 repowering project in relation to cooling water needs. 

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 facility is located immediately adjacent to Dockweiler and Manhattan State Beaches (to the west and north).  Residential areas of the City of Manhattan Beach adjoin the property's southern boundary, while a portion of a refinery lies to the east.  The area is fairly hilly, with the facility's switchyard located at an elevation several dozen feet above the generating units.  See Attachment B for an aerial view.
      
      The facility is owned by 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 currently 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, respectively.   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 years.  
      
      The switchyard is owned by Southern California Edison.
      
4.0 Cooling Water System and Intake Structure

      The facility currently operates one offshore CWIS.  The CWIS is comprised of a pipe located approximately 2600 feet offshore at a depth of 27 feet fitted with a velocity cap.  Water is withdrawn 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 bays 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 399 million gallons per day (mgd).
      
      El Segundo uses both biocides and heat treatment for biofouling control.  Sodium hypochlorite injection is used three times per day for 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 distance of about 2100 feet.

5.0 Impingement and Entrainment Information

      El Segundo conducted impingement mortality 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 stations serving as the source water control stations.  In 12 entrainment sampling events (collected samples every 6 hours in a 24 hour period) representing normal operations, 420,000 larvae (in 66 taxa), 570,000 eggs, and 431 larval shellfish were collected.
      
      Impingement was recorded during 12 (one per month) events, plus an additional 4 collections during heat treatments.  During normal operations, 22 fish (9 species) were collected, with no species being numerically 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 environmental impact occurring as a result of the operation of the El Segundo facility.

6.0 Cooling Tower Feasibility

      Facility representatives noted 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 nearby.  El Segundo is also located approximately 2 miles away from Los Angeles International Airport.
      
      Materials provided by the facility 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, was recent evaluated by the State Water Resources Control Board as to the potential to retrofit the facility to closed-cycle cooling. A report prepared for the California Ocean Protection Council (OPC) and State Water Board in 2008 identified several obstacles 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-cycle cooling was not feasible at El Segundo. 
      
7.0 Debris Handling

      Facility representatives did not identify any 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 capacity of 560 MW.  The original design for the new units called for a once-through cooling system, but the facility amended its design to utilize a closed-cycle dry cooling system.  Facility representatives noted that multiple factors influenced their decision to move towards dry cooling:  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 has raised the possibility that no new projects would be able to obtain the necessary air permits, including facilities repowering with wet cooling towers.   In selecting dry cooling, El Segundo is eliminating approximately 200 mgd of water withdrawals.
The repowering project is currently scheduled for completion in June 2011.  However, facility representatives noted they are currently behind schedule for constructing the new units, as permitting delays (related to air emissions permits) have caused delays.
      Facility representatives stated that they are open to the concept of repowering 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 by NRG Energy, an investor-owned company.
      
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

      Facility 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 facility with a low utilization rate does not make sense.
      
      Facility representatives noted that the Long Beach power plant has also repowered and eliminated its once-through cooling.  The existing cooling system had too many leaks and was replaced with dry cooling.

Attachments

Attachment A		List of Attendees
Attachment B		Aerial Photos
Attachment C	PowerPoint presentation "El Segundo Power Redevelopment Project" (September 1, 2009)
		

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, NRG

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 accompanying this document.