1 Site Visit Report

Harllee Branch Steam Electric Generating Plant 1100 Milledgeville Road Milledgeville, GA 31061 February 11, 2009

1.0 Background and Objectives

The Environmental Protection Agency (EPA) is in the process of developing 316(b) cooling water intake structure requi rements 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 generato rs and manufacturers to better understand the cooling water intake structure (CWIS) technologies in use at facilities, including the sitespecific characteristics of each facility and how these affect the selection and performance of CWIS technologies. EPA is also visiting f acilities to better understand cooling water use and specific is sues or technologies that can affect 316(b) compliance. Harllee Branch (Branch) was selected for a site visit due to

its use of a retrofitted helper cooling tower.

2.0 Facility Description

Branch is located on Lake Sinclair, wh ich is formed by the confluence of the Oconee and Little Rivers in central Georgi a. It was built in 1965 on a site of approximately 3100 acres and employs approximately 250 people. Branch is owned by Georgia Power and operates under NPDES permit GA0026051 (due to expire February 28, 2010).

3.0 Electricity Generation and Transmission

Branch operates four generating units with a total genera ting capacity of 1540 megawatts. The coal-fired units use eas tern bituminous coal from Appalachia. 1
Branch operates as a baseload generator 2 and each unit typically has outages of 1- 2 weeks every 18 months. Georgia Power also owns the switchyard and transmission equipment.

4.0 Cooling Water System and Intake Structure

Branch is located on a short peninsula in Lake Sinclair and is bounded by the Little River portion of th e lake to the south and a small inlet formed by

Beaverdam Creek to the north. 3 The two cooling water in take structures (CWISs)

for Branch are located at the end of a 400 f oot intake canal on the southern side of

1 Coal trains arrive daily, bringing approximately 70-80 cars of coal.

2 The facility operates all the time, but frequently reduces its generating load at night.

3 See Section 11.0 of this report for more information on Beaverdam Creek.2 the facility and withdraw from Lake Sinclair. 4 The CWIS for Units 1 and 2 consists of 3 coarse mesh traveling sc reens; the CWIS for Units 3 and 4 has 4 coarse mesh traveling screens. Both CW ISs also have trash racks. Debris and

fish removed from the screen are wa shed back into the intake canal. 5 The design through-screen velocity is between 1.1 a nd 1.3 feet per second, depending on lake

level.

Branch uses once-through cooling and di scharges to Beaverdam Creek. Each generating unit has 2 circulating pumps, wh ich are located at the condensers. The total design intake flow (DIF) is 1152 million gallons per day (mgd). 6 Actual intake flow (AIF) is typically at the design capacity.

5.0 Impingement and Entrainment Information

Branch completed one year of impinge ment sampling under the requirements of the now-suspended Phase II rule. These results have not yet been submitted to the state. The study found that the hydrau lic zone of influence for the CWIS

extended outside the mout h of the intake canal.

The facility was evaluating two technology alternatives to comply with the nowsuspended rule:

 Aquatic filter barrier at entrance of the intake canal (Gunderboom): Ultimately determined would not be feasible, due to the expected high operations and maintenance (O&M) cost s and high levels of nutrients in Lake Sinclair from local dairy farm s (leading to high biofouling growth rates).

 Expanded intake structure: There is no space at the existing CWIS for expansion or addition of screens. The facility designed a new intake structure that would be upstream of th e current CWIS in the intake canal.

The CWIS would be rebuilt with a “saw tooth” appearance to provide for more screen surface area, therefore re ducing the design intake velocity to 0.5 fps. The location of a fish return for this design was problematic, as

the distance to the return location would have been significant. Initial cost

4 One CWIS serves Units 1 and 2, the other Units 3 and 4.

5 Facility representatives noted that problems with re-impingement of debris or fish are rare; when problems do occur, maintenance workers collect the material and deposit into the landfill.

6 All four units operate at about the same load an d withdraw their full design flows. Under rare circumstances where an extended period of low genera tion is expected, a unit may reduce its intake flow by simply using one pump.3 estimates were $40 million. 7 This alternative was also unlikely to be implemented, as the costs outweighed the expected benefits. 8

Facility representatives also stated that Georgia wildlife offi cials conducted a fish population study of Lake Sinclair and estimated over 40 million fish resided in the

lake.

6.0 Cooling Tower Feasibility

In the 1980s, Lake Sinclair experienced some fish kills due to drought conditions, leading to a consent order and requirem ents to address thermal discharges. 9 The facility quickly ruled out closed-cycle coo ling due to the difficulty of tie-in with the condenser and the configuration of th e site (the peninsula is bounded by water on two sides, a roadway on a third, and is c onfined by the coal pi le and rail line to the west). 10

Instead, Branch installed a helper cooli ng tower in 2002 at a cost of $36 million; these helper towers are able to remove a pproximately half of the heat load from the facility. The helper tower array c onsists of 32 50-foot tall fiberglass mechanical draft cooling towers (arrange d as 16 100 ft x 50 ft towers back to back) located to the northw est of the generating units. The towers are grouped into 4 groups with each grouping capable of being served by any of the four circulating pumps. The towers employ drift eliminators 11 but do not include any design considerations for noi se or plume abatement. Each tower uses a 200 horsepower single speed fan.

The helper towers are operated seasona lly (May to October) and each cell can be controlled individually to meet the cooling needs of the facility; a flow-weighted temperature algorithm determines the optimal number of cells needed to meet the thermal discharge limits. 12 The maximum flow that can pass through the towers is 576 mgd, half of th e facility’s DIF.

7 Facility representatives expected minimal downtime dur ing construction of this configuration, as they would build half of the new CWIS at a time. They also noted that McDonough and Yates (both complete closed-cycle retrofits) experienced 6-8 weeks of downti me, during which time the facilities were able to perform other maintenance as well.

8 Impingement monitoring suggests few organisms are impacted by the CWIS; additionally, many of the impinged organisms are moribund shad.

9 Branch was the last facility constructed by Georgia Po wer before the passage of the Clean Water Act. All facilities constructed since that time employ closed-cycle cooling. See Section 14.0 for more information.

10 Facility representatives noted that the site was likely selected to minimize the length of condenser piping.

11 The vendor noted that modern drift eliminator technology reduces drift to approximately 1% of what was possible with technologies from 30 years ago.

12 Typically, when ambient water temperatures reach 90 °F, the helper towers begin operating. The facility can operate any combination of pumps, towers (with or without fans), and any number of fans to remove the appropriate amount of heat. In May and October, the towers operate about 10% of the time. From June to September, the towers operate most of the day and at about a 50% load at night.4 The helper towers are not connected to th e power block of the facility and would require significant re-piping to serve as part of a closed-cycle cooling system. 13
The re-piping would likely involve signi ficant excavation activities and would likely interfere with other elements of the generating units (e.g., precipitators).

The towers are permitted to use biocides, but have not needed them to date.

Facility representatives estimate that the cost to construct a second fully recirculating cooling tower of similar si ze (including tie-in with the condenser) would be approximately $110 million.

7.0 Debris Handling

Branch does not have significant problems with debris loading. However, facility representatives did note that seasonal debris loading woul d likely preclude the use of a barrier net or aquatic filter barrier.

8.0 Repowering/Future Uses

There are currently no plans to expand generating capacity or make other significant operational changes at Branch.

9.0 Cooling Ponds

There are no cooling ponds onsite.

10.0 Ownership

Branch is owned by an investor-owned company, 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. Geor gia Power’s rates are set by the Public Service Commission and any large expenditu res (such as cooling towers) would require approval before bei ng passed along to consumers.

11.0 316(a)

Beaverdam Creek is a small sub-watershed of Lake Sinclair. A large portion of the watershed is dammed by the ash pond upstream and does not reach the lake. As such, there is virtually no flow in the creek except for the facility’s discharge. The bridge over the outlet of Beaver dam Creek provides passage for state highway 24/441. Much of the bridge is actually a causeway, leaving minimal cross-sectional area for discharg e flows into Lake Sinclair.

13 Facility representatives stated that Branch serves as a good example of a cooling tower retrofit that minimized costs; they added that there have been no problems with the generating units or cooling water

systems.5 The once-through discharge for Branch flows into a retention area with a weir that empties into Beaverdam Creek. The pool forms the “source waterbody” for the helper towers, which discharge at the la ke bottom several hundred feet upstream of the primary discharge point. The remaining 50% of the once-through flow (i.e., that which does not pa ss through the helper towers) overflows the weir into

Beaverdam Creek.

The lake bottom location of the tower discharge creates an artificial thermal

stratification in Beaverdam Creek. Following approval by the state and subsequent litigation from environmen tal groups, a 316(a) study was conducted to verify that the configuration would support a balanced indigenous population (BIP). Following a 2-year monitoring study, Branch demonstrated that the

artificial stratification func tioned appropriately, even ma intaining stratification as it passed through the confined outlet from Beaver dam Creek embayment into Lake Sinclair. The study also conducted extensive transect sampling to ensure that an appropriate zone of pa ssage was provided for aquatic life. 14 Facility representatives added that the past 3 years have been periods of high power demand and severe drought, but that fish populations have not shown any signs of

stress.

12.0 Ash Handling

Branch uses a 311 acre ash pond to the north west of the site to handle its ash disposal. The main ash pond replaced several smaller ash ponds; the discharge from the main ash pond is now routed through the older ponds for additional treatment before being discha rged into Lake Sinclair.

The main ash pond was built in the earl y to mid-1980s, prior to recommended design standards for liners or ground water monitoring being implemented. 15
However, Georgia does have state requirements for dam safety that apply to the main ash pond due to the size of the dam and down-gradient residences. The dam is inspected annually by state officials and on a more frequent basis by Georgia Power engineers. 16

13.0 Air Emissions Controls

Facility representatives noted that no decision has been reached on emissions controls for Branch, but did note that a new landfill is likely to be constructed onsite. Scrubbers are being installed at othe r large plants. Georgia Power is currently studying flue gas desulfurizati on (FGD) wastewater treatment processes.

14 Facility representatives described the zone of passage as being defined as not more than 93°F with not less than 3.0 mg/l dissolved oxygen content.

15 In fact, no Georgia Power fac ilities have ash ponds with liners.

16 Georgia Power has an internal team of engineers to service the 19 reservoirs operated by the company. They conform to Army Corps of Engineers design and inspection standards.6 14.0 Additional Information

Facility representatives noted that of the 13 facilities in Georgia owned by Georgia Power, 7 employ closed-cycle cooling. The remaining 6 (including Branch) use once-through coo ling. Facility representativ es noted a wide variety of results in the impingement monitoring at these sites. For example, Mitchell has a small generating unit (not baseload) w ith a good sweeping flow and low intake velocity. Impingement counts were very low. As such, retrofitting to closedcycle cooling would not be a cost-effective solution. In fact, the facility would likely close if required to in stall closed-cycle cooling. 17

Georgia Power has an internal team of an alysts and engineers that evaluated each facility’s CWIS, suggested potential t echnologies, and calculated approximate compliance costs. These engineers tended to focus (at least initially) on solutions that would meet the 0.5 fps compliance al ternative for impingement mortality, as this is often a lower cost alternative. (S everal facilities already met this standard and one Georgia Power facility would ha ve been required to meet entrainment

standards under the now -suspended 2004 rule.)

Facility representatives stated that ma ny of the Georgia Power facilities with closed-cycle cooling are located on small ri vers. The largest of these facilities is located on a river with a 7Q 10 of 250 cfs; the second largest on a river with a 7Q10 of 380 cfs. They noted that they often must remind permitting authorities and the public of the differences between total withdrawal rates and consumptive (evaporative) losses at these facilities. Th ey also noted that none of these cooling

towers were installed fo r 316(b)-related reasons.

Facility representatives stat ed that it may be preferable in some circumstances for regulations to prescribe a technology, as th is provides certainty. Alternatively, the maximum amount flexibility possible with in the rule would be preferable. Facility representatives also stated that they would prefer th e rule incorporate a minimum threshold for adverse environmental impacts, as some technologies or solutions may not be cost-effective.

Attachments

Attachment A List of Attendees Attachment B Aerial Photos (Google Maps) Attachment C Aerial Photo (Side View)

Attachment D Aerial Photo (12/29/2002)

Attachment E Site Visit Photos

17 Facility representatives stated that many of Georgi a Power’s older facilities are being slowly phased out. They are attempting to maintain a good balance of fuel types (coal, natural gas, nuclear) but have not added any coal-fired facilities in some time. Georgia Power is also evaluating changing the fuel type for Mitchell to waste wood, as there is ample supply of wood products nearby.7 Attachment A--Lis t of Attendees

Paul Shriner, EPA Headquarters Jan Matuszko, EPA Headquarters Karrie-Jo Shell, EPA Region IV Kelly Meadows, Tetra Tech Bill Evans, Georgia Power Donna Hill, Georgia Power

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Please contact the EPA Docket Center, Public Reading Room to view this document.

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Telephone: 202-566-1744

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Email: docket-customerservice@epa.gov9 Attachment C— Aerial Photo (Side View)

Please see the attached materials.

Attachment D—Aerial Photo (12/29/2002)

Please see the attached materials. [oversize—in hard copy only]

Attachment E—Site Visit Photos

Please see the attached materials.