1 Site Visit Report McDonough - Atkinson Power Plant 5 551 South Cobb Drive Smy rna, GA 30080 February 1 1 , 2009 1.0 Background and Objectives The Environmental Protection Agency (EPA) is in the process of developing 316(b) cooling water intake structure requir ements 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 (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 facilities to better understand cooling water use and specific issues or technologies that can affect 316(b) compliance . McDonough - Atkinson Power Plant ( McDonough - Atkinson ) was selected for a site visit due to its use of a retrofitted recirculating cooling water s ys te m . 2.0 Facility Description McDonough - Atkinson is located on a 3 57 acre site 1 along the Chattahoochee River just northwest of Atlanta, Georgia. The facility opened in 1965 and employ s 134 people. McDonough - Atkinson is owned by Georgia Power and operates un der NPDES permit GA0001431 which expired December 31, 2008. Georgia Power submitted its NPDES permit application in a timely manner and is awaiting renewal of its permit by the state. 3.0 Electricity Generation and Transmission McDonough - Atkinson consists o f two 245 megawatt coal - fired generating units with a CUR of approximately 80% . These units burn eastern bituminous coal from Appalachia. McDonough - Atkinson is essentially a baseload facility . McDonough - Atkinson previously shared the site with the Atkins on Power Plant, as described in Section 6.0. Georgia Power has also begun a major repowering project at the site, as discussed in Section 8.0. The site name is now officially Plant McDonough - Atkinson.

1 As discussed in Section 8.0 below , McDonough - Atkinson acquired 50 acres adjacent to the original 250 - acre site to construct new generating units.2

4.0 Cooling Water System and Intake Structure The cool ing water intake structure (CWI S) for McDonough - Atkinson is located on the shoreline of the Chattahoochee River. The screen house consists of six intake bay s that previously housed six coarse mesh traveling screens , as well as a shared trash rack . After the facilit y converted to closed - cycle cooling, three of the intake bay s were closed and the remaining three were outfitted with a bulkhead and a fine mesh (3mm) Johnson wedgewire screen. 2 The existing fish return trough is no longer use d and the wedgewir e screens are cleaned b y an automated airburst sy stem. Facility

representatives noted that the wedgewire screens have operated well so far and that no maintenance has yet been required. The new design through - screen velocity is 0.5 feet per second (fps). As discussed below in Section 6.0, McDonough - Atkinson converted from once through cooling to closed - cycle cooling. Prior to the conversion, the facility ’s design intake flow was 39 3 million gallons per day (mgd). Currentl y, the facility ’s DIF is 19.9 m gd, 3 a 94.9 % reduction in design capacity . Similarly, the facility ’s previous actual intake flow (AIF) was approximately 317 mgd; the current AIF is approximately 6 .4 mg d . McDonough - Atkinson ’s discharge point is several hundred feet downstream of the CWI S. 5.0 Impingement and Entrainment Information McDonough - Atkinson has not conducted an y source water characterization or impingement or entrainment studies. 6.0 Cooling Tower Feasibility In the early

1990s, the Georgia Environmental Protection Division (EPD) c onducted a water quality study in the Chattahoochee River. Several lawsuits followed, largel y due to high nutrient content. In order to better accommodate economic development in the Atlanta area, 4 Georgia Power opted to retrofit McDonough - Atkinson to cl osed - cycle cooling. A four y ear compliance schedule for construction was developed.

2 The existing trash rack was k ept in place to protect the w edgewire screens. Facility representatives noted that this made installation of the new screens much more difficult. Additionally, the screens were not placed on rails; therefore any maintenance will be performed by divers. The facility selected w edgewire screens since the necessary capacity was much lower and it was expected that wedgewire screens would be easier to maintain. Georgia Pow er had also experienced good success with these screens at Yates, another Georgia Pow er Plant. 3 The CWIS has 3 new makeup pumps, each with a DIF of 6.6 mgd. In 2012 when McDonough - Atkinson is replaced by the gas - fired unit, the makeup pumps will be replaced by 3 new pumps with a total DIF of 21.6 mgd. 4 See Section 14.0 for more informatio n.3 In February

and April 2008, two mechanical draft cooling towers were brought online at McDonough - Atkinson at a cost of $96 million . The tower array consists of two 67 fo ot tall 10 - cell towers (arranged in a straight line) with 200 horsepower fans. Due to the proximity of an interstate (1/3 mile away), nearby residential areas, and on - site transmission lines adjacent to the towers, plume abatement was added to the towers in addition to drift abatement for approximately $10 million in additional costs. Plume abatement adds an extra air box on top of a traditional tower; recirculated warm water pre - heats air drawn into the air box via adjustable louvers. This warms and dehumidifies the evaporated water exiting the top of the tower, reducing the plume. The louver s ys tem allows the facilit y to operate the tower with or without plume abatement. McDonough - Atkinson ty picall y operates the plume abatement s ys tem on cold, humid d ay s and noted that the s ys tem provides reduced cooling when plume abatement is required. The towers are not equipped with noise abatement. Because space was extremely limited at McDonough - Atkinson , Georgia Power demolished its former Atkinson facility lo cated on adjacent propert y and moved maintenance buildings . Construction of each tower took approximately 3 y ears and the tie - in for each tower and condenser required a 6 - 8 week outage, during which time other maintenance and upgrades were also performed. To accommodate the conversion, the facility blocked the discharge point and added two circulating pumps to pump the water to the cooling towers. Due to concerns with existing infrastructure, much of the piping was routed above ground along the river. T he piping moves underground at the screen house. McDonough - Atkinson faced a number of challenges in converting the facility to closed - cy cle cooling:

 Plume abatement: this was the first time an y Georgia Power facility had installed plume abatement, requiring additional time for operators to learn proper operations and maintenance . Plume abatement also adds additional cost and height to the cooling towers.  Space constraints: Even with the demolition of the former Atkinson plant and relocation of buildings, the towers are sandwiched between transmission lines, buildings , the switch yard, and a railroad.  Tunnel strength: due to the long pumping path (from the old discharge point to the newly

constructed towers), a new pump station was added o n the riverbank atop the existing intake structure . To ensure proper flow, much larger circulating pumps than those previously used inside the plant were added. Unfortunately , the original condenser piping (from the CWI S to the condenser) was not designed as a high - p ressure s ys tem. Because Georgia Power found retrofitting the existing pumps to withstand high pressures extremely

difficult and costly

at a previous retrofit, it wanted to avoid increasing pressures in the existing tunnels. Instead, McDonough Atkinson bu ilt the new pumping s ys tem to pump water into the cooling4 towers. However, water exiting the towers is gravity fed back into the old screenhouse and condensers maintaining the original tunnel pressures.  Power requirements: the new circulating pumps and cooling tower fans require approximately

10MW to operate. The facility ’s station service sy stem was unable to provide that much power, so a separate transmission line from the transmission y ard was routed across the river and down to the new pump station.  Water treatment: McDonough - Atkinson previously had no treatment processes, requiring a new learning curve for facility operators. Several chemical feeds were added (biocide [sodium hy pochlorite], algaecide, and silt dispersant), creating new storage tank s and feed line conflicts. McDonough - Atkinson noted that they chlorinate the tower water with sodium hy

pochlorite in bursts. They close the cooling tower blowdown until the chlorine level is below detection. As a result, they do not discharge until chlo rination is complete. They indicated the s ys tem requires three to four times more chlorine than expected , but that they ty picall y operate at 3 - 4 cy cles of concentration . Also, prior to cooling towers, McDonough - Atkinson did not adjust the pH of its ash p ond water prior to discharg e; i t was combined with the cooling water prior to discharge at a ratio of 20:1 (cooling water: ash pond water). After the cooling tower retrofit, the facilit y now treats its ash pond discharges when necessary . 5  Underground pipi ng: Because of the age of the facility , McDonough Atkinson had no blue prints or information on existing underground piping. This presented a substantial challenge during retrofit.  Other surprises: the facility had to add a small pump in the screen hou se to supply service water to the existing Induced Draft Fan bearing coolers . Facilit y representatives were unsure of the operations and maintenance (O&M) costs for the new towers, but did note that some costs were higher than expected. 6 Overall, the tow ers have functioned as expected. 7.0 Debris Handling McDonough - Atkinson does not have significant problems with debris loading. The airburst s ys tem for the wedgewire screens appears to be adequate in addressing an y debris concerns. 8.0 Repowering/Future Uses McDonough - Atkinson is currentl y undergoing a major repowering project. Georgia Power purchased a large tract of land to the facilit y’s north and

5 I n - line pH adjustment is used for treatment. 6 For example, the towers are requiring more biocide treatment than projected. Since no tower blow down is permitted during chlorination cycles, this leads to some minor operational difficulties. Typically , the tow er cycles water 3 - 4 times before blowdown.5 construct ing two 800 MW gas - fired combined - cy cle units at the site . Both of these units will incorporate clos ed - cycle cooling. Once the first unit is operational, the power block at McDonough - Atkinson will be demolished 7 and a third 800 MW gas - fired combined - cycle unit will be constructed in its place ; the second and third combined - cycle units will use the cooli ng towers built for McDonough - Atkinson ’s existing units . A gas pipeline is currentl y under construction and scheduled for completion in summer 2010. The first unit is expected to be operational i n earl y 2011, the second in summer 2011 and the third in summer 2012. This conversion will transform the site from a 500 MW facility to a 2400 MW facility

with significantl y lower air emissions (in an urban non attainment zone for ozone ) and have minimal cooling water withdrawals. Georgia Power also examined the possibility of using “grey

water” from a nearb y wastewater treatment plant (WWTP), but ultimately concluded that the operation of the cooling towers would serve to concentrate pollutants and make it more difficult for McDonough - Atkinson to meet its own di scharge limits . Facility representatives were also concerned about obtaining a consistent volume of flow, as discharges from a WWTP can vary seasonally. 9.0 Cooling Ponds There are no cooling ponds onsite. 10.0 Ownership McDonough - Atkinson is owned b y an inve stor - owned compan y, Georgia Power , a Southern Company . Plants operated by Southern Company

provide approximately

95% of the electricity

in the state, making them the single largest entity for promoting economic development in the state. Georgia Power’s r ates are set b y the Public Service Commission and any large expenditures would require approval before being passed along to consumers. 11.0 316(a) McDonough - Atkinson was previousl y granted a variance from 316(a) requirements, but with the conversion to close d - cy cle cooling, the variance is no longer necessary . The facility operates at a condenser cooling water delta T of approximately

15 - 18°F. 12.0 Ash Handling Currently , the facility

uses an ash pond. As noted in Section 6.0, the wastes were previously commin gled with once - through cooling water. Once the cooling

7 The first unit will more than replace the generating capacity of McDonough - Atkinson ’s coal - fired units, as w ell as provide the necessary voltage support.6 towers were constructed, a new discharge point (with pH adjustment) was installed within the existing discharge structure . As discussed in Section 8.0, McDonough - Atkinson is converting to natural gas. Once this conversion is complete, the existing ash pond will be decommissioned. 13.0 Air Emissions Controls Currently , McDonough - Atkinson only uses precipitators and low NOx burners . As discussed in Section 8.0, McDonough - Atkinson is converting to natural gas. The new units will use Selective Catal yt ic Reduction (SCR) for emissions controls. 14.0 Additional Information As discussed in Section 6.0, the water quality of the Chattahoochee River was a significant concern for the state, Georgia Power, and the gene ral public in the earl y 1990s. McDonough - Atkinson is located approximately 40 miles downstream of an Arm y Corps of Engineers reservoir (Lake Lanier) that operates to meet a 750 cfs minimum flow in the Chattahoochee River just upstream of Plant McDonough - Atkinson, while maximizing its authorized uses, including flood control, navigation and hydropower. In 2008, drought led to a temporary reduction of the minimum flow target to 650 cfs during non - critical winter conditions . Additionally , several municipal WWTPs and industrial discharges are located upriver of the facility . The river also serves as the primary source of drinking water for the Atlanta area, as well as a navigation channel below Columbus, Georgia . Lake Lanier discharges from the bottom of the reservoir, leading to consistent ambient water temperatures of approximately 50 - 60° F. As a once - through facility , McDonough - Atkinson previously warmed the water temperatures to approximately

“normal” conditions; there appeared to be no adverse effects to aquatic life, even in low flow conditions. The water quality

study conducted by

the state concluded that the WWTPs would need to dramatically

improve waste treatment, as the dissolved oxygen content of the river was too low. The Chairman of Georgia P ower, also the chair of the Business Roundtable (an organization promot ing economic development in northern Georgia), became concerned that limitations on the WWTPs would ultimately

slow (or even halt) growth in the Atlanta area by reducing the capacity of the treatment plants and municipality ’s ability to issue new sewer use permits. 8 A follow - on anal ys is determined that converting McDonough - Atkinson to closed -

8 By extension, this would also affect Georgia P ow er’s growth.7 cy cle cooling would improve the waste assimilative capabilities of the river by a third to half

, thereb y reducing the burden on the WWTPs. 9 Attachm ent A List of Attendees Attachment B Aerial Photo s Attachment C PowerPoint Presentation (2/11/2009) Attachment D Site Visit Photos

9 The treatment plants are continuing to make upgrades, but no longer face the same scheduling and cost constraints.8

Attachment A -- List of Attendees Paul Shriner, EPA Headquarters J an Matuszko, EPA Headquarters Karrie - Jo Shell, EPA Region IV Kelly Meadows, Tetra Tech Bill Evans, Georgia Power Donna Hill, Georgia Power

# Copyrighted page/s removed. Copyrighted material is not available in Regulations.gov since it may not be reproduced without consent of the copyright holder. Please contact the EPA Docket Center, Public Reading Room to view this document. Address: 1301 Constitution Ave, NW Room 3334 Washington, DC 20004 Telephone: 202-566-1744 Fax: 202-566-9744 Email: docket-customerservice@epa.gov10

Attachment C
— PowerPoint Presentation (2/11/2009) Please see the attached materi als. Attachment D -- Site Visit Photos Please see the attached materials.