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## Implementation Strategies for Southern Company FGD Projects

Paper # 68

Darryl R Wall Principal Engineer, Chemical Processes Southern Company 42 Inverness Center Parkway
Bin B431 Birmingham, AL 35242

Edward C. Healy Consulting Engineer, Chemical Processes Southern Company 42 Inverness Center Parkway
Bin B431 Birmingham, AL 35242

John C. Huggins General Manager Environmental Strategic Planning Southern Company 42 Inverness Center Parkway
Bin B431 Birmingham, AL 35242



### ABSTRACT Southern Company has installed FGD systems on 12,000 MW of generation representing a capital investment of more than $3B dollars to date. Southern Company’s implementation strategy stretches over four states, ten stations, 34 units, two FGD technologies, and numerous suppliers. In cooperation with technology suppliers, Chiyoda Corporation and Advatech LLC., Southern Company has used various tactics to control capital costs, maintain high station reliability, and achieve state-of-the-art environmental performance. These tactics include minimizing the use of metals in materials of construction, utilizing templates in system design, and volume procurement of materials and equipment. In this paper the details of these strategies and the results (costs and performance) is shared.



### INTRODUCTION In 2003 Southern Company set about developing its strategies for the implementation of FGD systems across the coal fired fleet. From the outset it was recognized that this program was unprecedented in scope and size in the company’s recent history. As the program planning matured over the following years it came to span as much as 15 years, stretch across four states, ten generation stations, and 34 units, and ultimately affect2

22,000 gross MWs. Today’s estimates reveal that the required capital investments for this program may surpass $5 billion at its conclusion.

The year 2010 offers an opportunity of assessment as the first tier of the program draws near to completion. Figure 2 illustrates the magnitude of this first tier. More than 50% of Southern Company’s fleet of coal fired generation, about 13,000 MW, is to be equipped with FGD systems by the end of 2011.

Figure 1 Southern Company FGD Program 2008- 2011

The purpose of this document is to describe the strategies of the program and present findings of the assessment.3

Figure 2 Alabama Power Co Plant Gorgas FGD System

Figure 3 Georgia Power Co Plant Wansley FGD System



### STRATEGY DEVELOPMENT In 2003, a committee was formed of managers from operations, engineering & construction, and environmental affairs to establish a basis for the FGD program strategy. That committee set three governing precepts: design with an emphasis on operations,4

leverage the program size, and make use of continuous planning throughout project
execution.



### Emphasis on Operations Key to designing systems that recognize the needs of operations is to have active participation of the operating staffs in the design process. Southern Company established the role of Asset Manager for that primary purpose. This position is filled for each project with a person directly out of the respective plant who holds considerable plant experience as well as the respect of the plant. The responsibility of the Asset Manager in these projects is to look after his/her respective project with an emphasis on total life cycle costs and ensure the engagement of plant personnel in all project phases. Plant personnel provide valuable insight and their participation elicits a stronger sense of ownership by all team members. Ownership stimulates innovation. A rigid and linear project discipline is not conducive to innovation and frustrates those that are not accustomed to it. This can be trying when plant personnel want to revisit an issue, but the engineering and construction personnel have specific milestones in their sights. The Asset Manager and Project Manager have to weigh the different concerns and make a decision to the best benefit of the life of the plant.

Perhaps the most important point to a plant is maintaining fuel flexibility. Constraints on fuel sourcing can affect the viability of a plant and therefore, is a sensitive parameter on which to set bounds. An objective of a FGD design is that the FGD system is not a limitation to a unit’s fuel sourcing. When designing a FGD system and considering potential fuels, the primary points of interest are the following: sulfur content, heating value, and chlorides content. Sulfur content determines the scrubbing performance and most liquid and solids handling equipment sizes. The heating value of a fuel sets the size of the gas handling equipment sizes. A fuel’s chlorine content is a principal factor in deciding the materials of construction. Extensive analysis and deliberation goes into determining a set of fuel specifications for each FGD system. This specification encompasses all of the fuels of practical choice for a given unit or set of units. No unit is restricted to a specific fuel type, much less source or region.

A very important facet of operations is unit availability. A directive to the project teams is that the FGD system is not to adversely affect a unit’s availability. This is a challenge for any system design, but it takes even greater consideration for those systems that treat flue gas from multiple units in a single scrubber vessel. This consideration weighs heavily on the project teams when selecting equipment and materials of construction. The basis for the company’s confidence in selecting equipment and materials is the experience gained with the FGD system at Plant Yates. Southern Company’s participation in U.S. Department of Energy’s Clean Coal Technology program in the 1990’s has paid great dividends in FGD operating and maintenance experience. Southern Company co-sponsored a 100 MW demonstration of Chiyoda Corporation’s CT-121 FGD system on Georgia Power Company’s Plant Yates Unit 1. Operating and maintaining that system through the demonstration and the years following has provided many lessons.5

A key lesson from the Yates scrubber towards achieving great reliability is that the FGD system must be tolerant of a wide range of operations, even imperfect operations. FGD systems are notorious for the harsh, corrosive and erosive environments that they present. These environments vary throughout a FGD system; therefore, material selection must specifically consider each application and effectively envelope all practical exposures. The use of robust materials minimizes the loss of system operating time due to equipment failure. Materials of consideration in FGD systems include plastics, high chrome and nickel alloy steels, ceramics, and tile lined concrete.

Equipment redundancy is another important aspect of the robust FGD system design. The provision of redundant equipment allows for the system to continue unabated operation using the stand-by equipment after a failure of the primary equipment is experienced. Project teams evaluate the risk of failure of each system and weigh the cost for redundant equipment against the cost of failure.



### Leverage Program Size The size of the FGD implementation program presents opportunities to aggregate personnel, materials, and equipment. A strategy is to minimize unique, one time only, steps or actions. This is applied across a broad field including: engineering design, procurement of equipment and materials, shop surveillance, installation instruction, personnel instruction, and spares inventory.

The use of reference plants through the design and installation of the combined cycle fleet instilled an appreciation for the efficiencies achievable with defined and repeatable processes. Southern Company’s Engineering & Construction Services (E&CS) developed design templates – something of a modularization approach to design work. Common sizes were selected for sub-systems and equipment, e.g. scrubber vessels, slurry pumps, ball mills, and slurry tanks. Given Southern Company’s somewhat frequent use of 750 and 950 nominal MW boilers, the scrubber vessels are very amenable to templates. Then these templates are applied across the program as best fit each project and the respective component. Such an approach is ideally executed with a single technology set and linear project staging. However, given the number of projects, overlapping schedules, and concerns with the risk of relying upon a single technology, a modified approach is

necessary.

With much deliberation Southern Company developed a strategy that is based on two primary technology suppliers, Chiyoda Corporation and Advatech LLC. Southern Company benefits from a long relationship with Chiyoda Corporation, dating back to the FGD demonstration program at Gulf Power’s Plant Scholtz in the 1970s. Furthermore, Southern Company holds a license from Chiyoda to design and build the CT-121 Jet Bubbling Reactor (JBR) process on behalf of its affiliates and has made a significant investment in the development of this technology. This is a self-perform technology for Southern Company. Advatech is selected based on the performance strengths of its MHI Double Contact Flow Scrubber (DCFS) and its record of reliability.6

The potential for capital cost savings through volume procurement of materials and equipment is apparent. However, it is an unwieldy process that requires a great deal of work to identify capable suppliers, satisfy multiple schedules, and realize substantial savings. Southern Company established a small team to pursue this opportunity.



### Continuous Planning Planning entails information gathering, foreseeing necessary changes, cost estimating, budgeting and scheduling. Given the uncertainties of regulation, market pressures and financial consequences of a program of this size, Southern Company employs a continuous cycle of estimating, scheduling and budgeting. This process matured through the NOx control projects of the 1990s. It involves dual feedback loops of cost/budgeting and scheduling between the research & environmental affairs, engineering & construction and generation services organizations and corporate management.

R&EA and E&CS are charged with collecting intelligence concerning the regulatory climate and materials and labor markets, respectively. First, capital estimates and schedules are prepared for various control technology platforms, e.g. FGD system. Next, these platforms are assembled into strategy options with associated financial impacts. Corporate management scrutinizes these options and selects those that are to be included in the budgets of the operating companies. The selected options are then enhanced with greater detail to satisfy the requirements of the budgets and schedules of the operating companies. Once that is complete then it becomes part of an implementation plan. All environmental control projects are subjected to this process continuously throughout the life of a project, conceptual development to project close-out.

Running multiple parallel projects sets a great demand for engineering resources. Linking schedules across projects and with department manpower forecasts is important to minimize competition for resources between projects. The utility of design templates is apparent when these schedule links are made.



### IMPLEMENTATION Major components of that strategy include the use of two scrubber vessel technologies, Chiyoda Corporation’s CT-121 and Advatech’s DCFS, and selection of the materials of construction of the scrubber vessels, fiberglass reinforced plastic and tile lined concrete.

The use of two scrubber technologies, coupled with the use of in-house and out-sourced staffing, provides a sensible resource plan. Southern Company personnel are deployed on projects where the templates can be exercised. Out-sourced resources are utilized on one-of-a kind projects and to fill gaps where in-house resources are insufficient. Table 1 summarizes this strategy.7

Table 1. Scrubber Vessel Technology



### Design Templates A prominent benefit to the template designs is to more fully utilize the work that has already been accomplished. For instance a single tank size can be chosen to fit a number of applications across many projects. That tank design, complete with foundations, agitator, access, structure, electrical, and lighting can, to a large part, be utilized with each application. It is estimated that for every occasion that a template can be used for equipment such as tanks, pumps, blowers and the like a savings of 200 manhours is
realized.

Furthermore, the template approach, and its search for economies, fosters an environment of innovation and collaboration. The project teams use this environment to focus the design on finding efficiencies with operations, maintenance, and construction. An example is Southern Company’s use of C-modules for carbon steel ductwork. The ductwork is fabricated in field- erect-ready modules called C-shapes that are suitable for truck transport. These duct pieces can be lifted directly from a truck trailer and placed into position. This innovation resulted in significant improvement the productivity rates for ductwork installation, reducing the number of manhours per ton of ductwork by almost 40 hours per ton. Figure 4 is a photo of assembled C-modules.8

Figure 4 Ductwork Assembled from C-Modules

Another benefit is to extract more returns from the intellectual investment that has already placed with suppliers of template equipment. A significant investment is made in the education of our engineers and designers as well as the personnel of these suppliers in developing, assembling, and implementing these templates. For each new supplier a project team expends approximately 100 manhours in resolving issues related to communications, interpretations of documents, document submittals, and other general understanding issues.

A significant advantage in utilizing the templates is realized in project schedule. The ability to use design work completed on previous projects enables a project to begin design prior to receiving project specific drawings from equipment suppliers. In doing so, the supplier document submittal cycle is not as rigidly coupled to the engineering design deliverables schedule. This retracts at least 60 days from the design schedule.

The power stations also profit from the design templates in the operation and maintenance of the equipment. The power stations apply standardized training for operations and maintenance personnel across the generation fleet. Equipment standardization is a great aid in that effort, minimizing the number of distinct equipment that personnel must be proficient in its use and repair. Training time is estimated to be 4 hours per equipment per person trained.

Minimizing the number of equipment suppliers provides opportunities in the management of spare parts inventory. Southern Company can pool or share spare parts inventory across a number of power stations instead of each station having its own complete inventory. Each piece of FGD equipment introduced to the generating fleet has tens if not hundreds or thousands of associated spare parts.9



### Materials of Construction Southern Company holds a design requirement that materials directly exposed to scrubber gypsum slurry is to be able to withstand exposure to solutions and solids of chloride contents in excess of 20,000 ppm and pH across a range of 3.5 to 8.5. This is particularly important for the CT-121 JBR systems given their flexible range of pH operations. As a general rule the company minimizes the use of metals in such applications. Table 2 presents a portion of Southern Company’s FGD material selections.

Table 2. FGD Materials of Construction

Equipment Materials
Scrubber Vessels
Advatech DCFS Vessels Tile Lined Concrete Chiyoda CT-121 JBR Vessels Fiberglass Reinforced Plastic (FRP) Process Slurry Tanks Fiberglass Reinforced Plastic (FRP) Slurry Pump Casing Liners Rubber and High Chrome Alloy Steel Slurry Pump Impellers High Chrome Alloy Steel Knifegate Valve Gates Super Duplex Alloy Steel (SAF 2507) Chimney Flues Fiberglass Reinforced Plastic (FRP)
Outlet Ductwork Fiberglass Reinforced Plastic (FRP) CT-121 Gas Cooling Duct FRP, PVDF, borosilicate block
Structural Steel Galvanized Carbon Steel Slurry Piping FRP and HDPE

Based on Southern Company’s experience with the Yates FGD system, plastics hold considerable resistive advantages over steels and other materials in FGD applications. Plastic materials of construction are used extensively in Southern Company FGD systems. The Southern Company worked with Chiyoda to develop a JBR vessel design conducive to construction with fiberglass reinforced plastic. Figure 5 is a photograph of a JBR vessel during construction. The 950 JBR is 119 feet in diameter and the initial construction was a rather imposing task; particularly, given the overlap in the construction schedules for many of the projects. The construction schedule for the first JBR project, Plant Bowen unit 3, was pulled forward to give more time for constructing the first JBR and to complete the spinning of the vessel prior to starting other JBR projects. In doing so lessons from the Bowen 3 project were more effectively transferred to the other projects. A similar approach was also taken for the spinning of the chimney
liner cans.10

Figure 5. CT-121 JBR Vessel During Construction



### Piping The Southern Company project teams place a lot of emphasis on pipe design in pursuit of the desired FGD system reliability. Based on the experience with the Yates scrubber and the experiences of some mechanical design personnel in the pulp and paper and chemical industries, it was decided to rely heavily on piping constructed of fiberglass reinforced plastic (FRP) and high density polyethylene (HDPE) plastic.

FRP pipe, as shown in Figure 6, has excellent corrosion resistance and with an abrasion resistant (AR) liner is also very good for abrasive services, such as limestone and gypsum slurry. For external applications, FRP pipe with a 110 mil interior AR liner is used. Inside of scrubber vessels a 110 mil interior and exterior AR liner is used. FRP pipe systems are usually rated for 100 or 150 psi.

Improper joining methods and inadequate pipe support are the two major causes of FRP pipe failures. Southern Company avoids the use of socket joint FRP pipe in pressurized systems. The reason behind this is the uncertainty of joint adhesion inherent with sockets. Butt and wrap joints are the preferred means of joining FRP and have proven quite adequate in scrubber applications. Pipe support for FRP is also critical. FRP cannot be supported like steel pipe. FRP is an orthotropic, composite material that does not handle excessive pipe movement or fatigue very well. In general, Southern Company attempts to support our FRP pipe with a rigid (anchor-to-anchor) or semi-rigid (anchor and guide) approach in order to eliminate or control movement. Also, FRP pipe does not tolerate point loading. Sharp, irregular edges at the steel/pipe interface are avoided. Saddles or11

cradles are used to spread the load. Concentrated loads, such as valves or long risers, are independently supported to minimize the bending stress on the FRP pipe.

Like FRP, HDPE pipe also possesses excellent corrosion and abrasion resistance. HDPE pipe is generally joined by butt fusion in new installations. Proper fused joints are homogeneous and are therefore as strong and resistant as the pipe itself. For repair and retrofit work, electrofusion couplings or Victaulic Style 995 HDPE couplings are used. Generally, HDPE is not appropriate for process temperatures greater than 140 °F, but gravity systems up to 180 °F are acceptable. It must be remembered that HDPE pipe is de-rated for pressure based on temperature increase.

Figure 6 FRP Piping

There are a couple of design considerations to be aware of when using HDPE. The most obvious is the rate of thermal expansion. Due to its low modulus of elasticity (E ~ 47,000 psi @ 100 °F), we use an anchor-to-anchor approach to restrain the HDPE for long runs on bridges, see Figure 7. It is anchored near each end and guided to prevent buckling. The pipe literally absorbs its own expansion. Care must be taken to communicate the resulting anchor loads for bridge steel design.

The second consideration when using HDPE is the decreased flow area that results from the thicker pipe wall. It isn’t uncommon to have to go up a pipe size to accommodate the12

flow when going from carbon steel or FRP pipe to HDPE pipe. This is a critical point and has been the cause of systems failing to meet their design parameters.

High nickel alloy is a third pipe material Southern Company uses in scrubber applications. Due to its extremely high cost, it is used sparingly. However, there are applications involving gypsum slurry with high chloride content and elevated temperatures inside the scrubbers where it is used.

Figure 7 HDPE Piping



### Equipment Redundancy Equipment redundancy is an important consideration in system reliability. The provision of redundant equipment allows for the system to continue unabated operation using the stand-by equipment after a failure of the primary equipment is experienced. System processing lines are outfitted with multiples of equipment where an application is judged to be either at known risk of failure or of high detriment to performance should failure occur. This judgment is based upon utility industry practice and Southern Company experience at Plant Yates. The following are examples of Southern Company FGD system redundancy practices:

Limestone Reclaim The limestone reclaim equipment includes two 100% reclaim conveyors and a crossover conveyor atop of the limestone storage silos. Either reclaim conveyor can be used to fill either silo. The level of redundancy is provided because of risk of failure associated with the grinding circuit and not that of the conveyors themselves.13

Limestone Grinding Circuit Due to the abrasive nature of the limestone being processed, the ball mill grinding circuit is deemed to be the most severe equipment duty of the FGD system. Robust materials are employed here, but that alone does not effectively mitigate the risk of equipment failure. Therefore, plants are equipped with two 100% circuits, one operating and one stand-by. A circuit includes limestone silo, weigh feeder, ball mill, mill lubrication, mill product tank, mill product pump, cyclone classifiers, as well as interconnecting and supply piping. The duty of the mill product pump is deemed to be especially difficult; therefore, two pumps are provided with each circuit, resulting in 4 x 100% redundancy.

Pumps All pumps are provided in pairs, one operating and one stand-by. This is a completely redundant pump arrangement including motor, valves, and other accessories. The stand-by pump auto-starts upon failure of the operating pump. This design feature follows the industry standard for FGD pumps.

All slurry pumps are designed for hard rock mining services, horizontal, fully lined, ductile iron, and slow rotating speed. They are equipped with no-flush mechanical seals. The casing liners are natural rubber and the impellers are constructed of a high chrome alloy. The pump/motor arrangement is ZV, reverse overhead motor support
for ease of maintenance.

Booster Fans The FGD booster fan sets are sized so that the loss of a fan does not force a dramatic reduction in the unit load. For units equipped with a pair of axial fans, one of these fans is capable of providing the necessary draft to support 80% or more of that unit’s generating capacity.

Pipelines The FGD system includes pipelines for the transport of limestone slurry, gypsum slurry, and water. The limestone grinding circuits and the gypsum handling systems are located rather remotely from the scrubber vessels, and thus the system has very long pipelines between these locations. If a leak or plug occurs in one of these long pipelines, then it can be difficult to locate. For these reasons redundant gypsum slurry transfer and limestone slurry transfer pipelines are provided. Redundant piping is beyond industry norms, but we deem it as prudent for these two applications given their criticality to operations and severity of service.

Electrical Two different station service schemes are used to provide a robust electrical system for normal operation with flexibility to manage the loss of a piece of electrical supply14

equipment. The first scheme is the traditional supply which provides a starting transformer fed from the transmission system and a running transformer supply fed from the generator bus. After the generating unit is started from the transmission system the station service loads are transferred from the starting to running supply. This tends to isolate these station service loads from the transmission system, providing the most electrically stable supply. This is used for the booster fans to prevent fan trips and subsequent unit trips due to transmission system disturbances. The second supply scheme provides station service from two independent transmission lines, transformers and station service systems. The loads for this scheme remain connected to the transmission system, which eliminates the possibility of the loads on this system from being without power due to an unsuccessful bus transfer. The gas cooling pump or recycle spray pump (depending on CT-121 or DCFS system) loads are powered from this supply at all times. Also, redundant scrubber loads are fed one from each independent transmission system, which increases the scrubber operation reliability.

Instrumentation In accordance with Southern Company requirements for instrument installation, all instruments supplying input to a control algorithm are provided in redundant pairs. Also, the use of switches is avoided in favor of transmitters.



### Cost Control Use of continuous planning/budgeting loops proved to be necessary given the unprecedented escalation experienced 2005 - 2009. During that timeframe, average annual escalation was 12.5%. This challenged the projects ability to forecast capital expenses and satisfy budgets. Figures 8 and 9 are provided to illustrate the scale of this price escalation for two of the major materials in the Southern Company FGD program, thermoset plastic resin and structural steel. 1

Figure 8 Cost Index for Thermoset Plastic Resin15

Figure 9 Cost Index for Structural Steel

The material quantities for the FGD program are incredible:

· 200,000 tons of steel

· 110,000 tons of ductwork

· 13,000 tons of FRP pipe

· 7,400 miles of electrical/control cable

· 1,500,000 cubic yards of concrete.

The magnitude of the material quantities and the escalating cost pressures serve as a greater incentive to find savings in aggregating material and equipment purchases. Table 3 presents a summary of a portion of the materials purchased through volume procurement contracts for FGD and SCR projects, 2005 to 2010. It is estimated that Southern Company has saved 10% on the cost of equipment and materials by aggregating program purchases.

Table 3 Materials Purchased Through Volume Procurements

Material Total Contracts Value ($M)

Structural Steel $206

Ductwork $177 FRP Shop Fabrication $142 Mechanical Equipment $68 Electrical Equipment $52

Southern Company places an emphasis on efficient management of spare parts. It is crucial to both hold critical spares and limit costs associated with spares and their storage. A committee of personnel from the plants and corporate supply chain management completed a study determining the criticality of FGD spare parts. They developed a calculus to rate criticality based on lead times, cost, and exclusivity. Then they devised schemes for how best to share parts across the fleet and minimize the number of each part in stores. Decisions that resulted in notable savings include the following:16

· Axial fan parts shared by Plants Gorgas and Hammond

· Axial fan parts shared by Plants Crist and Miller

· Ball mill and slurry pump parts shared by Plants Bowen and Wansley

Through such efforts the committee trimmed 25% from the spare parts direct costs.



### 2010 ASSESSMENT At this date, 2010, Southern Company has completed the installation of the majority of its FGD program. The 12,000 MW of FGD installed to date holds most of the top tier of the company’s coal fired fleet. The program cost at this point is in excess of $3 billion. The remainder of the program may stretch beyond 2015, include an additional 10,000 MW, and require a further investment of more than $2 billion.

Performance of the FGD systems has been good, exceeding design requirements for SO 2 removal, availability, and others. The company is investigating FGD operations and performance to determine best efficiency points. Each unit is subjected to rigorous performance tuning and parametric testing. Operations and performance of the systems are subjected to ongoing scrutiny. Automated reports are generated on a weekly and monthly basis presenting each system’s performance against a set of metrics. At each month’s end an executive summary of these reports is issued to corporate management. Southern Company is also examining system performance in light of impending air and water regulations so as to fully leverage this investment.

The use of the design templates significantly reduced engineering design manhours with each successive JBR based FGD project. Figure 10 illustrates this trend. Due to the escalation in material costs, differences in project scope and other factors that same trend is not apparent in total project costs.

Figure 10 Scrubber Island Design Hours

0 5000 10000 15000 20000 25000

Bowen 3 & 4 Wansley 1&2 Gaston 5 Barry 5Design Manhours17

Southern Company’s FGD project costs range from about $200/kW to $600/kW with an average of $320/kW. That average compares well with industry data. A 2009 survey of scrubber costs by EUCG found the industry average to be $390/kW, see Figure 11. That is a 20% difference or savings across the total program - a savings about $700 million to the Southern Electric System rate payers.

Figure 4 Southern Co and Industry FGD Costs

Southern Company considers the first tier of the FGD program to be a success. That success is in large part due to the strategies of the two FGD technologies, materials of construction, volume procurements and others outlined in this document. However, looking forward on the program, the company is now weighing decisions on the second tier implementation. The economics for the generating units included in the second tier are considerably different than that of the first tier. The basis for the strategies must be adapted to fit these different economics. The balance between first capital costs and life cycle costs will change. As a result a number of the program strategies will also change.



### SUMMARY The Southern Company FGD program is at a point of substantial completion with approximately 12,000 gross MW of FGD systems in service and another 10,000 MW to be installed in coming years. Southern Company’s strategies for the program are set upon three precepts: design with an emphasis on operations, leverage the program size, and continuous planning through the life of a project. The document provides selected details of the strategies employed including the use of Chiyoda CT-121 JBR and Advatech DCFS FGD technologies, design templates, materials of construction and cost control. As a result of these strategies the average cost of the Southern Company FGD program is about 20% below that of the industry – a savings of approximately $700 million for the Southern Electric System rate payers.

As the program moves forward the economics change and the strategies have to be adapted fit, striking a new balance between capital costs and life cycle costs.18



### ACKNOWLEDGEMENTS The authors wish to acknowledge the contributions of many of our colleagues at Southern Company including: Bill Garmon, Craig Maxson, and Edgar Nunez.



### REFERENCES

1. Sharp, G; Escalation, Economics, Regulation, and Its Impact on North American Utility Construction Programs; ECUG Spring Workshop, 2010.