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Comprehensive Technical Feasibility and Cost Evaluation
Study
Alcoa Power Generating Inc., a subsidiary of Alcoa Corporation
Alcoa Warrick Power Plant
Project No. 85014
Final 1/31/2018
Comprehensive Technical Feasibility and Cost Evaluation
Study
prepared for
Alcoa Power Generating Inc., a subsidiary of Alcoa Corporation
Alcoa Warrick Power Plant Newburgh, Indiana
Project No. 85014
Final 1/31/2018
prepared by
Burns & McDonnell Engineering Company, Inc. Kansas City, Missouri
COPYRIGHT © 2018 BURNS & McDONNELL ENGINEERING COMPANY, INC.
Technical Feasibility and Cost Study Final Table of Contents
Alcoa Warrick Power Plant TOC-1 Burns & McDonnell
TABLE OF CONTENTS
Page No.
1.0 INTRODUCTION ............................................................................................... 1-1 1.1 Final Rule Requirements...................................................................................... 1-2 1.2 Report Organization ............................................................................................. 1-3
2.0 CLOSED CYCLE RECIRCULATING SYSTEMS .............................................. 2-1 2.1 Technical Feasibility ............................................................................................ 2-1
2.1.1 Description of the Technologies Considered ........................................ 2-1 2.1.2 Discussion of Land Availability ........................................................... 2-7 2.1.3 Discussion of Other Available Water Sources ...................................... 2-9 2.1.4 Factors That Make the Technology Impractical or Infeasible ............ 2-14
2.2 Cost Evaluation .................................................................................................. 2-15 2.2.1 Cooling Tower Cost Estimate Methodology ...................................... 2-15 2.2.2 Cooling Tower Cost Estimate Basis ................................................... 2-16 2.2.3 Compliance Costs ............................................................................... 2-18 2.2.4 Social Costs ......................................................................................... 2-19
3.0 FINE MESH MODIFIED TRAVELING SCREENS ............................................. 3-1 3.1 Technical Feasibility ............................................................................................ 3-1
3.1.1 Description of the Technologies Considered ........................................ 3-1 3.1.2 Discussion of Land Availability ........................................................... 3-5 3.1.3 Discussion of Other Available Water Sources ...................................... 3-5 3.1.4 Factors That Make the Technology Impractical or Infeasible .............. 3-6
3.2 Cost Evaluation .................................................................................................. 3-18 3.2.1 Cost Estimate Methodology ................................................................ 3-18 3.2.2 Cost Estimate Basis............................................................................. 3-18 3.2.3 Compliance Costs ............................................................................... 3-20 3.2.4 Social Costs ......................................................................................... 3-21
4.0 FINE MESH CYLINDRICAL WEDGEWIRE SCREENS .................................... 4-1 4.1 Technical Feasibility ............................................................................................ 4-1
4.1.1 Description of the Technologies Considered ........................................ 4-1 4.1.2 Discussion of Land Availability ........................................................... 4-3 4.1.3 Discussion of Other Available Water Sources ...................................... 4-3 4.1.4 Factors That Make the Technology Impractical or Infeasible .............. 4-4
4.2 Cost Evaluation .................................................................................................. 4-10 4.2.1 Cost Estimate Methodology ................................................................ 4-10 4.2.2 Cost Estimate Basis............................................................................. 4-10 4.2.3 Compliance Costs ............................................................................... 4-12 4.2.4 Social Costs ......................................................................................... 4-13
5.0 WATER REUSE AND ALTERNATE SOURCES OF COOLING WATER ........ 5-1
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5.1 Technical Feasibility ............................................................................................ 5-1 5.1.1 Description of the Operational Measure ............................................... 5-1 5.1.2 Discussion of Land Availability ........................................................... 5-1 5.1.3 Discussion of Other Available Water Sources ...................................... 5-2 5.1.4 Factors That Make the Technology Impractical or Infeasible .............. 5-2
5.2 Cost Evaluations .................................................................................................. 5-2
6.0 SUMMARY ........................................................................................................ 6-1
7.0 LITERATURE CITED ........................................................................................ 7-1
- COOLING TOWER SKETCH - SOCIAL COST STUDY - MODIFIED TRAVELING SCREEN SKETCHES - CYLINDRICAL WEDGEWIRE SCREEN SKETCH
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LIST OF TABLES
Page No.
Table 1-1: Report Organization ............................................................................................... 1-3 Table 2-1: Comparison of Cooling Tower Types and Screening Level Evaluation ................ 2-3 Table 2-2: Cooling Tower Design Basis Summary ................................................................. 2-5 Table 2-3: Municipal Wastewater Sources in the Vicinity of the Alcoa Warrick
Power Plant .......................................................................................................... 2-13 Table 2-4: Estimated Project Costs for Mechanical Draft Cooling Towers .......................... 2-18 Table 2-5: Estimated Cooling Tower Project O&M .............................................................. 2-19 Table 2-6: Total Project Life Cycle Costs ............................................................................. 2-19 Table 2-7: Total Compliance and Social Costs for Mechanical Draft Cooling Towers ........ 2-21 Table 3-1: Estimated Entrainment Reduction using 0.5-mm Fine Mesh Modified
Traveling Screens at AWPP ................................................................................. 3-15 Table 3-2: Estimated Entrainment Reduction using 1.0-mm Fine Mesh Modified
Traveling Screens at AWPP ................................................................................. 3-16 Table 3-3: Estimated Entrainment Reduction using 2.0-mm Fine Mesh Modified
Traveling Screens at AWPP ................................................................................. 3-17 Table 3-4: Estimated Project Costs for Replacement of Existing Screens with
Modified Traveling Screens with a Fish Handling and Return System ............... 3-20 Table 3-5: Total Compliance and Social Costs for Fine Mesh Modified Traveling
Screens ................................................................................................................. 3-21 Table 4-1: Vendor Sizing for Cylindrical Wedgewire Screens ................................................... 4-2 Table 4-2: Field and Laboratory Egg and Larvae Exclusion Rates Using Wedgewire
Screens ................................................................................................................... 4-6 Table 4-3: Mean Density and Standard Deviation of Eggs Collected in Ambient,
Control, and Test Samples ..................................................................................... 4-7 Table 4-4: Mean Density and Standard Deviation of Freshwater Fish Larvae
Collected in Ambient, Control, and Test Samples ................................................. 4-8 Table 4-5: Estimated Entrainment Reduction using 2.0-mm Fine Mesh Cylindrical
Wedgewire Screens at AWPP .............................................................................. 4-10 Table 4-6: Estimated Project Costs for Fine Mesh Cylindrical Wedgewire Screens ............ 4-12 Table 4-7: Estimated O&M for Fine Mesh Cylindrical Wedgewire Screen ............................. 4-13 Table 4-8: Total Project Life Cycle Costs for Fine Mesh Cylindrical Wedgewire
Screens ................................................................................................................. 4-13 Table 4-9: Total Compliance and Social Costs for Fine Mesh Cylindrical Wedgewire
Screens ................................................................................................................. 4-15
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LIST OF FIGURES
Page No.
Figure 2-1: Potential Locations for the Mechanical Draft Cooling Towers ............................. 2-8 Figure 3-1: Through-Screen Velocities under Various Debris Loading Conditions ................ 3-7 Figure 3-2: Head Losses under Various Debris Loading Conditions ....................................... 3-8 Figure 3-3: Probability of Retention of Freshwater Drum Larvae on Fine Mesh
Screens at AWPP ................................................................................................. 3-11 Figure 3-4: Probability of Retention of Carpsucker/Buffalo Larvae on Fine Mesh
Screens at AWPP ................................................................................................. 3-12 Figure 3-5: Probability of Retention of Herring Larvae on Fine Mesh Screens at
AWPP ................................................................................................................... 3-12
Technical Feasibility and Cost Study Final List of Abbreviations
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LIST OF ABBREVIATIONS
Abbreviation Term/Phrase/Name
°F degrees Fahrenheit
§ Section
AACE Association for the Advancement of Cost Engineering
ACC air cooled condensers
AIF actual intake flow
APGI Alcoa Power Generating Inc.
ASHRAE American Society of Heating, Refrigeration, and Air Conditioning Engineers
AWPP Alcoa Warrick Power Plant
BOD Biological Oxygen Demand
BTA best technology available
CCRS closed-cycle recirculating system
COD Chemical Oxygen Demand
CWA Clean Water Act
CWIS cooling water intake structures
DCS distributed control system
DIF design intake flow
EM entrainment mortality
EPA U.S. Environmental Protection Agency
EPRI Electric Power Research Institute
FEMA Federal Emergency Management Agency
fps feet per second
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Abbreviation Term/Phrase/Name
FRP fiber reinforced plastic
ft feet
gpm gallons per minute
HCD head capsule depth
hp horsepower
HCW horizontal collector well
HVAC heating, ventilation, and air conditioning
IDEM Indiana Department of Environmental Management
IDNR Indiana Department of Natural Resources
IM impingement mortality
in. inches
MGD million gallons per day
mm millimeters
MW megawatt
NPV net present value
NPDES National Pollutant Discharge Elimination System
O&M operation and maintenance
OSHA Occupational Safety and Health Administration
PVC polyvinyl chloride
psig pounds per square inch
TDH total dynamic head
TL total length
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Abbreviation Term/Phrase/Name
TSS total suspended solids
USACE U.S. Army Corps of Engineers
WWTP wastewater treatment plants
Technical Feasibility and Cost Study Final Introduction
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1.0 INTRODUCTION
On August 15, 2014, the U.S. Environmental Protection Agency (EPA) published in the Federal Register
the National Pollutant Discharge Elimination System – Final Regulations to Establish Requirements for
Cooling Water Intake Structures at Existing Facilities and Amend Requirements at Phase I Facilities
(EPA, 2014a). The Final Rule establishes requirements under Section (§) 316(b) of the Clean Water Act
(CWA) to ensure that location, design, construction, and capacity of cooling water intake structures
(CWIS) reflect the best technology available (BTA) for minimizing adverse environmental impacts. The
purpose of this action is to reduce impingement and entrainment of fish and other aquatic organisms at
CWIS used by power generation and manufacturing facilities to withdraw cooling water. The regulations
apply to facilities that use CWIS to withdraw water from waters of the U.S. and have or require a
National Pollutant Discharge Elimination System (NPDES) permit. The Final Rule establishes
requirements for facilities that are designed to withdraw more than 2 million gallons per day (MGD) of
water from waters of the U.S. and use at least 25 percent or more of the water withdrawn exclusively for
cooling purposes.
The Alcoa Warrick Power Plant (AWPP) is a division of Alcoa Power Generating Inc. (APGI), a wholly-
owned subsidiary of Alcoa Corporation. AWPP is a four-unit, 823-megawatt (MW), coal-fueled, steam-
electric power station located in Newburgh, Indiana. The facility uses once-through (open-cycle)
condenser cooling with the Ohio River as the source and receiver of cooling water. APGI wholly owns
three of the four generating stations, which were placed into service in the early 1960s. The largest unit,
Unit 4, is jointly owned by APGI and Vectren Inc., a utility company.
AWPP is a base-load station that generates a continuous supply of electricity throughout the year to
power the Alcoa Warrick Operations manufacturing facility. In addition to electrical power, the power
plant also provides potable water, steam, and high temperature water across the plant. These services are
critical to the various production processes throughout the Warrick Operations manufacturing facility.
The Final Rule applies to AWPP due to the following:
• AWPP has a NPDES permit and is a point source for industrial discharge of wastewater. The
NPDES permit effective date is August 31, 2013, and the permit expiration date is July 31, 2018.
• AWPP uses one CWIS in a once-through cooling water system. The Ohio River is the source and
receiver of the once-through cooling water system. The total DIF at AWPP is 400,000 gallons per
minute (gpm) or 576 MGD. The design intake flow (DIF) of 576 MGD at AWPP is therefore
greater than the 2 MGD criteria. The actual intake flow (AIF) is 518.0 MGD based on data from
Technical Feasibility and Cost Study Final Introduction
Alcoa Warrick Power Plant 1-2 Burns & McDonnell
January 1, 2010, to December 31, 2014. This time period was selected because it is most
representative of intake flows when the smelter is in operation.
• AWPP uses approximately 91 percent of the water withdrawn from the Ohio River for cooling
water purposes; therefore, the percentage of flow withdrawn from the Ohio River is used
exclusively for cooling purposes is greater than 25 percent criteria.
Because AWPP is subject to the Final Rule, has a DIF that is greater than 2 MGD, and an AIF greater
than 125 MGD, AWPP is required to prepare permit application requirements § 122.21(r)(2) through (13)
for submittal to the Indiana Department of Environmental Management (IDEM).
1.1 Final Rule Requirements The Final Rule under Section (§) 122.21(r)(10), Comprehensive Technical Feasibility and Cost
Evaluation Study, requires the submittal of an engineering study of the technical feasibility and
incremental costs of candidate entrainment mortality (EM) control technologies to support the
determination of site-specific BTA for entrainment (EPA, 2014a). The Final Rule requires that the
evaluation includes the technical feasibility of closed-cycle recirculating systems (CCRS), fine mesh
screens with a mesh size of 2 millimeters (mm) or smaller at the CWIS, and water reuse or alternate
sources of cooling water.
Per the Final Rule at §122.21(r)(10)(i), the technical feasibility of each candidate EM control technology
is to include the following:
(A) A description of all technologies and operational measures considered (including alternative designs of closed-cycle recirculating systems such as natural draft cooling towers, mechanical draft cooling towers, hybrid designs, and compact or multi-cell arrangements).
(B) A discussion of land availability, including an evaluation of adjacent land and acres potentially available due to generating unit retirements, production unit retirements, other buildings and equipment retirements, and potential for repurposing of areas devoted to ponds, coal piles, rail yards, transmission yards, and parking lots.
(C) A discussion of available sources of process water, grey water, waste water, reclaimed water, or other waters of appropriate quantity and quality for use as some or all of the cooling water needs of the facility.
(D) Documentation of factors other than cost that may make a candidate technology impractical or infeasible for further evaluation.
Per the Final Rule at §122.21(r)(10)(iii), facility costs must be adjusted to estimate social costs. Costs
must be presented as the net present value (NPV) and the corresponding annual value, and costs must be
clearly labeled as compliance costs or social costs. The applicant must separately discuss facility level
compliance costs and social costs, and provide documentation as follows:
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(A) Compliance costs are calculated as after-tax, while social costs are calculated as pre-tax. Compliance costs include the facility’s administrative costs, including costs of permit application, while the social cost adjustment includes the Director’s administrative costs. Any outages, downtime, or other impacts to facility net revenue, are included in compliance costs, while only that portion of lost net revenue that does not accrue to other producers can be included in social costs. Social costs must also be discounted using social discount rates of 3 percent and 7 percent. Assumptions regarding depreciation schedules, tax rates, interest rates, discount rates and related assumptions must be identified.
(B) Costs and explanation of any additional facility modifications necessary to support construction and operation of technologies considered, including but not limited to relocation of existing buildings or equipment, reinforcement or upgrading of existing equipment, and additional construction and operating permits. Assumptions regarding depreciation schedules, interest rates, discount rates, useful life of the technology considered, and any related assumptions must be identified.
(C) Costs and explanation for addressing any non-water quality environmental and other impacts. The cost evaluation must include a discussion of all reasonable attempts to mitigate each of these impacts.
1.2 Report Organization This report provides the NPDES permit application requirements in the Final Rule under §122.21(r)(10),
Comprehensive Technical Feasibility and Cost Evaluation Study. The report provides a comprehensive
technical feasibility study and cost evaluations for a CCRS, fine mesh traveling screens, fine mesh
cylindrical wedgewire screens, and alternate water sources. A chapter has been devoted for each
candidate EM reduction technology that provides the technical feasibility and cost evaluation of that
technology. Table 1-1 shows the organization of this report.
Table 1-1: Report Organization
Chapter Relevant
Permit Requirement Report Chapter Title 2 §122.21(r)(10)(i) and (ii) Closed Cycle Recirculating Systems 3 §122.21(r)(10)(i) and (ii) Fine Mesh Traveling Screens 4 §122.21(r)(10)(i) and (ii) Fine Mesh Cylindrical Wedgewire Screens 5 §122.21(r)(10)(i) and (ii) Water Reuse and Alternate Sources of Cooling Water 6 N/A Summary 7 N/A Literature Cited
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2.0 CLOSED CYCLE RECIRCULATING SYSTEMS
The following provides a comprehensive technical feasibility study and cost evaluation of CCRS.
2.1 Technical Feasibility As required in the Final Rule under §°122.21(r)(10)(i), the following provides an evaluation of the
technical feasibility of this technology.
2.1.1 Description of the Technologies Considered Cooling towers are used to reduce the temperature of a water stream by extracting heat from the water and
emitting it to the atmosphere. Evaporating cooling and dry cooling systems are proven technologies that
reduce the amount of intake flow, thereby reducing entrainment and impingement. Closed-cycle cooling
via cooling towers uses 3 to 5 percent of the volume of intake water necessary to operate once-through
cooling systems by recycling the cooling water through the tower and ejecting waste heat to the
atmosphere (EPA, 2014a). EPA estimates that freshwater cooling towers reduce impingement mortality
(IM) and entrainment by 94.9 percent (EPA, 2014a). The actual entrainment reduction is dependent upon
the cooling tower specifications (including the cycles of concentration).
A variety of cooling tower designs may be used to retrofit facilities that currently utilize once-through
cooling systems. These cooling towers may be grouped by several factors (Electric Power Research
Institute [EPRI], 2011a), including:
• Air flow method: natural draft, mechanical forced draft, or mechanical induced draft
• Method of heat transfer: wet, dry, or wet/dry (hybrid) towers
• Air flow direction: counter- or cross-flow
• Arrangement: rectilinear (in-line or back-to-back) or round
Mechanical draft towers use fans to force or draw air through the circulated water. The water falls over
fill surfaces, which helps increase the contact time between the water and the air, maximizing heat
transfer between the two. A portion of the water evaporates, which cools the remainder of the water.
Cooling rates of mechanical draft towers depend upon various parameters, such as fan diameter and speed
of operation and fills for system resistance.
Mechanical draft towers are typically categorized as either forced or induced draft. In a forced draft
tower, the fan is located in the ambient air stream entering the tower, and the air is blown through. Forced
draft towers are characterized by high air entrance velocities and low exit velocities. In an induced draft
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tower, the fan is located in the exiting air stream and draws air through the tower. Mechanical draft towers
are available in a large range of capacities and can be grouped together in assemblies of two or more
individual cooling towers or “cells.” Multiple-cell towers can be linear, square, or round depending upon
the shape of the individual cells and whether the air inlets are located on the sides or bottoms of the cells.
Mechanical draft plume-abated towers have very similar designs and operations to non-plume-abated
mechanical draft cooling towers. However, they reduce or eliminate visual plumes by reducing the
exhaust air relative humidity. Plume abatement can be done various ways, specific to each supplier. Some
methods include using coils to cool a portion of the water by a dry method to reduce overall evaporation
and moisture in the exhaust air. Other methods include mixing dry ambient air with the wet air leaving the
tower fill to reduce the moisture in the exhaust air.
Natural draft or hyperbolic cooling towers make use of the difference in temperature between the ambient
air and the hotter air inside the cooling tower. Air flow through this type of tower is produced by the
density differential that exists between the heated (less dense) air inside the tower and the relatively cool
(more dense) ambient air outside the tower (SPX Cooling Technologies, Inc., 2009). Typically, these
towers tend to be quite large (250,000 gallons per minute [gpm] and greater), and occasionally in excess
of 500 feet (ft) in height (SPX Cooling Technologies, Inc., 2009). As hot air moves upwards through the
tower, cooler ambient air is drawn into the tower through an air inlet at the bottom. There are two main
types of natural draft towers (also options for mechanical draft towers):
1. Crossflow tower: air flows horizontally, across the downward fall of water
2. Counterflow tower: air moves vertically upward through the fill, counter to the downward fall of
water (although design depends on specific site conditions).
Crossflow towers require a lower pump head and less maintenance than counterflow towers because of
their simple water distribution system. Operating costs for a crossflow tower are lower than that for a
counterflow tower. However, crossflow towers are less efficient than counterflow towers at rejecting heat
from the water; therefore, crossflow towers are typically larger to compensate for less efficient cooling.
There are two main dry cooling options: direct cooling and indirect cooling. Direct cooling systems,
known as air cooled condensers (ACC), directly transfer heat from the steam to the atmosphere and
condense the steam inside tubes. Indirect cooling systems, sometimes considered air cooled heat
exchangers, transfer heat from the circulating water (inside tubes) to the atmosphere. Both options utilize
fans to increase air flow and heat transfer. Dry cooling performance is based on ambient dry bulb
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temperature, while wet cooling tower performance is based on ambient wet bulb temperature.
Consequently, wet cooling typically results in better cooling performance.
A comparison of the cooling tower types is provided in Table 2-1.
Table 2-1: Comparison of Cooling Tower Types and Screening Level Evaluation
Attribute
Cooling Tower Typea Mechanical-
draft Evaporative
Cooling Towers (Base
Case) Mechanical-draft
Plume Abated Wet Natural
Draft Dry Air Cooled
Hybrid (Wet/Dry)
Footprint Area Arranged in one or more rows of single or back-to-back cells or in circles
Arranged in one or more rows of single or back-to-back cells or in circles
Could be larger or smaller depending on separation of mechanical-draft evaporative cooling tower rows.
Largest (2-4 times larger than base case) due to wider air- cooled section; arrangement limited to in-line
Larger (1-3 times larger than base case) due to wider air- cooled section; arrangement limited to in-line
Height Typically 40-60 ft plus 9 ft for fan stack
Typically 40-70 ft plus 9 ft for fan stack
Can approach 500 ft or more
Approx. 2-3 times higher than base case
Approx. 1.5 times higher than base case
Visible Vapor Plume
Lower elevation plume; fogging / icing can occur
Minimal to no visible plume
Higher visible plume; minimal, if any, fogging / icing
None Minimal to no visible plume
Particulate Matter Emission
Base case-depends on TDS, cycles of concentration, and drift eliminator efficiency
Similar to base case
Similar to base case
None Less than base case depending on frequency of use for dry portion of tower
Water Consumption
8 to 12 gpm/MW
8 to 12 gpm/MW (could be reduced slightly when plume abatement in operation depending upon manufacturer)
Similar to base case
None 1.5 to 12 gpm/MW
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Attribute
Cooling Tower Typea Mechanical-
draft Evaporative
Cooling Towers (Base
Case) Mechanical-draft
Plume Abated Wet Natural
Draft Dry Air Cooled
Hybrid (Wet/Dry)
Noise Emission
Base case-fan and cascading water noise
Similar to base case
No fan noise; similar water noise to base case
Greatest fan noise; no water noise
Greater fan noise than base case; less water noise
Solid Waste (Sediment)
Base case-depends on water/air quality, basin size, use of dispersing agents
Similar to base case
Similar to base case
None Similar to or less than base case
Cycle Efficiency
Base case Equal to base case, but reduced when plume abatement in operation
Equal to base case
Lowest; lowest summer output
Lower than base case; lower summer output
Energy Penaltyb
Base case Similar to base case
Less than base case
Higher than base case (highest)
Higher than base case
Capital Cost Base case Higher than base case (approx. 1.5-2 times more)
Higher than base case (approx. 3-5 times more)
Highest (approx. 5-7 times base case)
Higher than base case (approx. 3-5 times more)
Installation Cost/Difficulty
Base case Similar to base case
Higher than base case
Higher than base case
Higher than base case
Operating Cost Base case Similar to but can be slightly higher than base case, depending upon manufacturer
Lower than base case
Highest Higher than base case
Source: EPRI 2011a (a) gpm/MW = gallons per minute per megawatt (b) Energy penalty includes both loss of generation capacity associated with decreased efficiency, and additional power loads associated with operating the modified cooling system (i.e., parasitic loads).
Based on efficiency, economics, and environmental factors, a mechanical-draft evaporative cooling tower
would be the preferred alternative for retrofitting a once-through cooling facility to closed-cycle cooling
at the Alcoa Warrick Power Plant (AWPP). Other types of towers were also considered, but not carried
forward for additional analysis. Circular towers were considered but eliminated because they provided no
apparent additional advantage. Local height ordinances may prevent natural draft towers at this site, and
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available space limits their use. Additionally, natural draft towers cost substantially more than
mechanical-draft evaporative cooling towers, but do not provide proportional benefits in other areas,
particularly for power generating stations the size of AWPP. Dry towers are larger, and there may be
insufficient space onsite for these towers. Also, dry towers cost substantially more for procurement and
installation, and result in additional loss of plant performance. The use of hybrid towers, if mandated,
would require a larger footprint than mechanical draft cooling towers, but available space at the site could
preclude use of hybrid towers. Plume-abated towers cost substantially more for procurement than
mechanical draft towers and because of the distance from the conceptual cooling towers to the plant, other
industrial facilities, highway, and residences, plume impacts to these areas are expected to be minimal to
non-existent. Therefore, a mechanical draft cooling tower is the preferred alternative at AWPP, and the
feasibility of a mechanical draft cooling tower is evaluated in the following subsections.
The preliminary design for a mechanical draft cooling tower retrofit at AWPP would include the
installation of two new, back-to-back cooling towers, one with 12 cells and the other with 16 cells. The
conceptual cooling towers (Alternative 1) would be located northwest of the power plants on top of
existing landfills (Figure 2-1). A conceptual sketch is provided in Appendix A. Both cooling towers are
oriented in a northeast direction to be parallel with respect to predominant summer wind, for optimal
performance. The cooling tower design basis for a mechanical draft cooling tower at AWPP is
summarized in Table 2-2. The design wet-bulb temperature used for AWPP is 78.2 °F.
Table 2-2: Cooling Tower Design Basis Summary
Itema Descriptionb Cooling Tower Type Wet cooling, counterflow, mechanical draft cooling tower without plume
abatement. Towers are FRP material with induced fans. Fans
Drives Single speed drives on all fans Horsepower rating 250 hp
Number of cells Units 1 and 3 Tower: 12 cells; Units 2 and 4 Tower: 16 cells Tower dimensions Units 1 and 3 Tower: 350 feet by 110 feet (length x width)
Units 2 and 4 Tower: 475 feet by 110 feet (length x width) Design conditions
Design dry bulb 88.1 °F Design wet bulb 78.2 °F (ASHRAE 1% wet bulb)
Tower design Approach 7 °F
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Itema Descriptionb Recirculation allowance
2 °F
Range Units 1 and 3 Tower: 18.6°F; Units 2 and 4 Tower: 20.2°F Water flow rate Units 1 and 3 Tower: 171,100 gpm; Units 2 and 4 Tower: 234,700 gpm Drift 0.0005% Plume abatement Not included Fire protection Not included Lightning protection
Included
Freeze protection Hot water bypass to the basin will be included as well as isolation of individual cells (though not recommended).
Condensers Modifications Install new condenser modules (bundles) for all four unit condensers,
including tubes, tubesheets, waterboxes and structural support. All will be designed for increased system pressure.
Circulating Water Pipe Modifications Reinforce portions of existing pipe near and underneath plant. New pipe
installed elsewhere. Two pipelines, one for each tower. Type C301 Largest diameter 96 inches (U2 and U4) Other Notable Scope Circulating water pumps
Decommission existing circulating water pumps. Install 3 x 50% pumps in Units 1 and 3 tower pump pit. Install 4 x 33% pumps in Units 2 and 4 tower pump pit.
Design flow rate (per pump)
Units 1 and 3 system: 85,600 GPM; Units 2 and 4 system: 78,300 GPM.
Design head (TDH)
>85 ft
Auxiliary cooling system
Replace auxiliary cooling heat exchangers because of increased circulating water temperature and pressure (assumed)
Water treatment Clarification and/or filtration included. Service water tanks included. Wastewater treatment excluded (blowdown routed directly to river).
Raw water source New collector well with redundant supply pumps (if aquifer pump testing confirms feasibility).
Electrical Transformers and associated equipment to feed additional auxiliary loads (a) TDH = total dynamic head (b) FRP = fiber reinforced plastic; hp = horsepower; °F = degrees Fahrenheit; ASHRAE = American Society of Heating, Refrigeration, and Air Conditioning Engineers; gpm = gallons per minute
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2.1.2 Discussion of Land Availability Three alternate cooling tower locations were considered for this site (Figure 2-1).
• Alternative 1: Northwest of power plant on existing landfills
• Alternative 2: North of selected area, between laydown and Route 66
• Alternative 3: East of process plant on existing landfill
Alternative 2 was eliminated as a potential location due to its distance from the units and the associated
challenges to route circulating water pipe to and from this location. This location would incur substantial
costs for the circulating water pipe route because of underground utilities and would also place the towers
near the highway, which could result in potential fogging and icing impacts on Route 66.
Alternative 3 was eliminated as a potential location because this area is actively used for storage (clean
fill) of dirt, gravel, and concrete for ongoing construction projects and the placement of a cooling tower
here would require the relocation of this storage. However, there are no other onsite areas for the storage
to be relocated. Additionally, the circulating water pipe route would encounter major obstructions for this
location, which adds costs and risk. This location would also present potential plume impacts on Route
66.
Alternative 1, which was selected as the basis location for this study, presents its own challenges
including its distance from the power plant and the requirement to remove landfill material. However, this
circulating water pipe route would be more feasible than Alternative 3. Existing infrastructure and
underground utilities would need to be relocated or demolished, as appropriate, to accommodate potential
cooling towers and associated piping (Appendix A). Also of important note, a topographical survey of the
proposed area would need to be completed to determine if the existing landfills and proposed location is
within the floodplain. Survey data indicated that this area was above the floodplain. However, the current
FEMA maps indicate the existing landfills are within the one percent floodplain. FEMA maps may not be
indicative of the actual elevations of the site and the proposed location may not actually be in the
floodplain. If the proposed cooling tower location is determined to be within the floodplain, additional fill
will be required.
COPYRIGHT © 2017 BURNS & McDONNELL ENGINEERING COMPANY, INC.
Source: Esri, and Burns & McDonnell Engineering Company, Inc. Issued: 7/14/2017
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NORTH
1,000 0 1,000500
Scale in Feet
Figure 2-1Potential Locations for the Mechanical Draft
Cooling TowersAlcoa Warrick Power Plant
Alcoa Power Generating, Inc.Warrick County, Indiana
ST66 ST61
GG400
GG350
Arnold Rd
Darl ington Rd
W State Route 66
Alternative 1
Alternative 2
Alternative 3
Alternative SiteU1/U3U2/U4
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2.1.3 Discussion of Other Available Water Sources The use of alternative water sources such as process water, gray water, wastewater, and reclaimed water,
could potentially reduce or eliminate surface water withdrawals from the Ohio River, thereby reducing or
eliminating impingement and entrainment at AWPP. Other potential alternative water sources could
include groundwater, agricultural irrigation drainage, mine drainage, and produced water from oil and gas
or mining operations.
Alternative water sources are generally considered potentially feasible as sources of make-up water to
closed-cycle cooling systems such as cooling towers, but typically cannot provide a sufficient quantity for
once-through cooling. The use of an alternative water source also typically requires the installation of
long-distance supply pipelines from the alternate source water location to the power plant and
pretreatment of the water to reduce corrosion, fouling, or scaling problems or to address issues of
wastewater disposal.
Several factors are critical in determining the feasibility of using an alternative water source:
• Source water quantity
• Source water quality and pretreatment
• Distance from the facility
• Land uses and neighborhood characteristics through which the supply and return lines would
have to be installed
• Local regulations
These factors can substantially add to the difficulty and overall cost of the closed-cycle cooling tower
retrofit project.
Alternate water sources to supply makeup water to the cooling tower at AWPP were identified and
evaluated based on the aforementioned critical factors. A new cooling tower at AWPP would require
approximately 9,070 gpm of makeup water supply. Irrigation drainage, produced water, and mine
drainage are not available to the plant. Groundwater and effluent from wastewater treatment plants
(WWTP) are potential alternate water sources for cooling tower makeup and are evaluated below.
2.1.3.1 Groundwater The Ohio River alluvial aquifer underlies the AWPP with the Ohio River in close proximity. Based on the
geologic logs obtained from the Indiana Department of Natural Resources (IDNR), there is substantial
available aquifer thickness with depths to bedrock of approximately 120 feet. Geologic logs of the wells
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in the area indicate that the aquifer is primarily medium to coarse sand and gravel. Review of available
information on groundwater wells in the area indicates that yields of 2,500 to 3,000 gpm are common.
Two typical well types are vertical wells or horizontal collector wells. The well logs available near the
AWPP were vertical wells constructed in the Ohio River alluvium. The following provides a brief
description and analysis of each.
Vertical wells are constructed in a borehole drilled vertically through the aquifer to penetrate the water-
bearing portions of the formation. Typically, the lower portion of the well is made of slotted or wire-
wrapped stainless steel screen to allow water to flow into the well. The upper section of the well is steel
or polyvinyl chloride (PVC) casing to contain the pumping equipment. Drawdown occurs when a well is
pumped, and is cumulative between wells. Therefore, appropriate spacing between wells would be
necessary to avoid interference drawdown, which would limit the yield of the wells. The appropriate well
spacing is determined by conducting a pumping test and calculating the conductivity and storativity of the
aquifer. An initial estimate for the required distance at AWPP is 500 feet between wells to keep
drawdown interference below 10 percent of the total drawdown. Four to five vertical wells would be
required to achieve the desired yield of 9,070 gpm and have redundancy for operations and maintenance.
Construction of these wells would require a 36- to 42-inch borehole drilled to bedrock, and installation of
a 24- to 30-inch diameter screen and casing. Each of these wells would require power, pumps, meter
valves, and piping to connect to the cooling tower.
Horizontal collector wells (HCW) utilize a caisson extending to bedrock and slotted or wire wrapped
screens extending horizontally out from the caisson like spokes on a wheel. HCW’s have the advantage of
producing significantly higher volumes of water from a single installation. A single installation minimizes
piping runs to connect the wells, infrastructure associated with multiple well locations, and well
interference concerns. With the available aquifer thickness at the site and transmissive aquifer material
indicated by the well logs, it is likely that a single HCW could yield the required volume of 9,070 gpm for
the cooling tower makeup flow. Redundancy would be achieved by the installation of three, 50 percent
capacity pumps installed in the well (as assumed in the cooling tower design basis). Therefore, a HCW is
recommended at AWPP to provide makeup water to the cooling tower because it minimizes the
infrastructure and operation and maintenance (O&M) requirements for the raw water supply.
2.1.3.2 Wastewater The following provides discussion on the feasibility of using industrial and municipal wastewater at the
Alcoa Warrick Operations facility as potential alternate water sources at AWPP.
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Industrial Wastewater
The Alcoa Warrick Operations facility discharges wastewater from the aluminum manufacturing plant.
Based on the uncertainty of the industrial wastewater quality, the treatment requirements and feasibility
for use of this waste stream can greatly vary. If the wastewater source is high in suspended solids or
metals, clarification and filtration are likely required before any use within the cooling tower system.
Another possible issue with this wastewater source is the possibility of high ammonia concentrations.
Conversion of this ammonia by chlorination is needed based on cooling tower limitations. Ammonia in
the wastewater would require significant chlorine feed, and the amount of chlorine fed would increase the
chloride concentration of the water, which could impact the circulating water system materials of
construction and cooling tower cycles of concentration, therefore increasing overall water use. As such,
the use of the industrial wastewater from the aluminum manufacturing plant is not considered feasible due
to the significant amount of treatment that would be required.
Municipal Wastewater
Five municipal wastewater treatment plants are located within 20 miles of the AWPP (Table 2-3).
However, four of these facilities are located 8 to 16 miles away from AWPP. The distance of these
facilities from the AWPP, the industrial and residential neighborhoods through which the supply and
return lines would have to be installed, the dense underground utilities, and the regulations affecting the
project would make their use as alternate water sources very difficult and expensive, particularly as
compared to using groundwater.
The closest municipal wastewater treatment facility is the Newburgh WWTP, located approximately 1.8
miles northwest of AWPP. The Newburgh WWTP design flow is 4.6 MGD. Using this alternate water
source would reduce AWPP’s intake flow by 35 percent; however, several issues with using wastewater
supply exist. Wastewater treatment supplies can be secondary or tertiary treated water. Secondary treated
wastewater is aerated for Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD)
reduction and clarified. Tertiary treatment includes filtration and disinfection following secondary
treatment. If the wastewater source is from a secondary treatment system, then tertiary treatment must be
included at AWPP prior to cooling tower use. Typical filters used for tertiary treatment include
continuously backwashed upflow filters, disc filters, or compressible filters to remove total suspended
solids (TSS) prior to being utilized for cooling tower makeup. Another issue with a wastewater treatment
supply is the possibility of high ammonia concentrations. Conversion of this ammonia by chlorination is
needed based on cooling tower limitations. Ammonia in the wastewater would require significant chlorine
feed, and the amount of chlorine fed would increase the chloride concentration of the water, which could
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impact the circulating water system materials of construction and cooling tower cycles of concentration,
therefore increasing overall water use.
Given that the Newburgh WWTP cannot provide 100 percent of the required makeup flow, secondary or
tertiary treatment would need to be completed at AWPP, and several environmental clearances and
road/utility permits and agreements would need to be obtained, groundwater using a single HCW is the
most promising alternate water source for the cooling tower makeup.
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Table 2-3: Municipal Wastewater Sources in the Vicinity of the Alcoa Warrick Power Plant
Municipal Wastewater
Plant
Quantity Available
(MGD)
Distance from Plant
(miles) Land Use from Facility to
Source Regulations Affecting Project
Percent Reduction in Cooling
Tower Makeup
Boonville Municipal WWTP
2.9 9.7 Cultivated crops Archeological, wetland, and threatened and endangered species clearances; road and utility permits/agreements
22.2
Chandler Municipal WWTP
8.3 8.0 Industrial, cultivated crops, and residential neighborhoods
Archeological, wetland, and threatened and endangered species clearances; road and utility permits/agreements
63.5
Evansville Eastside WWTP
18.0 13.2 Industrial, cultivated crops, wetlands, and residential neighborhoods
Archeological, wetland, and threatened and endangered species clearances; road and utility permits/agreements
> 100
Evansville Westside WWTP
21.7 16.1 Industrial, cultivated crops, wetlands, and residential neighborhoods
Archeological, wetland, and threatened and endangered species clearances; road and utility permits/agreements
> 100
Newburgh WWTP
4.6 1.8 Industrial, and cultivated crops
Archeological, wetland, and threatened and endangered species clearances; road and utility permits/agreements
35.2
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2.1.4 Factors That Make the Technology Impractical or Infeasible In addition to the space requirements associated with the installation of cooling towers, other engineering
factors were considered in the assessment of whether a closed-cycle cooling retrofit is feasible. An EPRI
research program included an independent evaluation of the degree of retrofit difficulty for approximately
125 facilities, and qualitatively categorized whether the retrofit would be relatively “easy, moderate, or
difficult” using the following list of primary factors (EPRI, 2011b):
• Distance between the cooling tower and the main facility and difficulty of tie-ins to existing
structures and components, including auxiliary power for new loads
• Interference from existing underground and overhead utilities
• Suitability of site geology and topography
• Need to reinforce condensers or water supply tunnels
• Need for plume abatement
• Drift deposition on- or off-site
• Need for noise reduction
• Need to bring in alternate sources of makeup water
• Requirements to modify balance-of-plant equipment
• Need to re-optimize the cooling water system
Based on the above factors, a cooling tower retrofit at AWPP is considered difficult. Site-specific
engineering considerations and factors associated with locating cooling towers at AWPP are listed below:
• The significant distance between the proposed cooling tower locations and main plant area would
require long runs of pipe to be installed, which would require shoring and impact potential
unknown underground obstructions.
• Surface material from the landfills and clean fill storage would have to be removed and backfilled
with soil to install the cooling towers. Finding a suitable location for the required quantity of
landfill material would be challenging and expensive. There are no known suitable locations for
the clean fill storage material.
• Due to the increased head/pressure of the system, the circulating water pipe must be replaced or
reinforced with a lining/wrap system. Both options are labor intensive and costly. Furthermore,
reinforcing or replacing the pipe underneath the plant will be difficult because of pipe turns,
unknown undergrounds, and lack of accessibility.
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• The proposed cooling tower location (Alternative 1) may be in or encroach on the floodplain.
Prior surveys indicated that the proposed cooling tower location was not in the floodplain.
However, the current Federal Emergency Management Agency (FEMA) maps indicate the
existing landfill is within the one percent floodplain. The FEMA maps may not be indicative of
the actual elevations of the site and the proposed location may not actually be in the floodplain. If
the proposed cooling tower location is determined to be within the floodplain additional fill will
be required. Additional permits may also be required including the Town of Newburgh
Floodplain Development Permit, which could also potentially include hydraulic river modeling
that shows a no-rise to the floodplain elevation. If no-rise is unable to be shown, additional
mitigation options may be required such as additional grading. If the proposed cooling tower
location is determined to be outside or above the one percent floodplain a Letter of Map
Amendment or Letter of Map Revision to FEMA.
Detailed discussions of the following non-water quality environmental and other impacts associated with
retrofitting to a CCRS are discussed in the Non-water Quality Environmental and Other Impacts Study:
• Changes in energy consumption
• Air pollutant emissions
• Human health impacts
• Environmental impacts
• Changes in noise
• Impacts to safety
• Facility reliability
• Changes in water consumption
2.2 Cost Evaluation As required in the Final Rule under §°122.21(r)(10)(iii), the following provides the compliance and social
costs associated with this technology.
2.2.1 Cooling Tower Cost Estimate Methodology An indicative screening level cost estimate (Association for the Advancement of Cost Engineering
[AACE] Class 4) was developed for the conversion of the once-through cooling system to a CCRS. The
estimate was mostly developed based on a parametric model using previous projects and quotes as
reference. Major design parameters (i.e. circulating water flowrate and total steam turbine output)
representing the application at AWPP were utilized to adjust cost factors based on established cost
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relationships and functions. Some of the design parameters used to develop the cost estimate are
summarized in Table 2-2. The specific design parameters were not just used to scale or adjust total project
cost. Instead, cost scale factors were applied to all major equipment and major discipline specific
activities to adjust cost groups based on site specific design parameters. Costs were also captured for
differences in scope. All cost groups were combined to develop screening level total direct costs. Area
specific labor rates were considered to adjust associated costs.
Indirect and other costs were determined based on recent similar projects, utilizing percentages as
described in the following sections.
2.2.2 Cooling Tower Cost Estimate Basis The following sections provide the basis for the cooling tower project estimate. The purpose of the
estimate basis is to describe the major scope of the cost items shown in the estimate summaries. The
estimate is based on a multiple-subcontract approach.
2.2.2.1 Direct Costs Total direct costs account for equipment, material, and labor costs for the project. The following provides
the cost estimate basis for each category summarized in Table 2-4.
Equipment
The equipment supply includes the procurement of all major equipment required for conversion of the
once-through cooling system to a CCRS. Table 2-2 summarizes the design basis and major equipment
scope. The following additional minor equipment scope (not included in Table 2-2) is included in the
costs:
• Compressed air
• Chemical feed for cooling tower
• Blowdown pumps and associated equipment
Costs for all equipment were adjusted from reference projects based on equipment specific design
parameters.
Installation Costs and Balance of Plant Modifications
This cost group includes all labor, rental, receiving, and material costs associated with the installation of
the equipment and balance of plant modifications. Local labor rates were used to adjust costs from recent
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Burns & McDonnell projects, while several other design parameters were used to adjust costs associated
with quantities and labor productivity. The major plant systems included in the scope of these costs are
summarized in Table 2-2. The scope of these costs includes the following:
• Civil
• Concrete and Deep Foundations
• Piping
• Structural Steel
• Architectural/Buildings
• Electrical
• Instrumentation and Controls
• Demolition
• Miscellaneous
2.2.2.2 Indirect Costs, Contingency, and Owner Costs Indirect Costs
Indirect costs include estimated costs for the following:
• Construction management (including managing of multi-sub contracts) based on size of the
project and recent Burns & McDonnell projects (4.5 percent of direct costs)
• Engineering based on size of the project and recent Burns & McDonnell projects (6 percent of
direct costs)
• Start-up management and materials, based on project size and application
All sales taxes, financing fees, and escalation are excluded from the estimate.
Project Contingency
Project contingency (15 percent of total direct and indirect costs) was included to cover accuracy of
pricing, commodity estimates, and omissions from the defined project scope. This contingency is not
intended to cover changes in the general project scope (i.e. addition of buildings, addition of redundant
equipment, addition of systems, etc.) nor major shifts in market conditions that could result in significant
increases in contractor margins, major shortages of qualified labor, significant increases in escalation, or
major changes in the cost of money (interest rate on loans).
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Owner Costs and Contingency
Costs have been included for traditional Owner’s costs (5 percent of total direct costs, indirect costs, and
project contingency) such as project support staff, additional operators, outage time, financing,
permitting, etc. This allowance is based on project experience and size and not based on a specific
buildup of expected Owner costs for this project. Owner contingency was also included as 5 percent of
the total project cost in order to cover potential change orders that could occur over the project duration.
2.2.3 Compliance Costs The following provides the compliance costs associated with this technology.
2.2.3.1 Capital Costs The screening level capital cost for the mechanical draft cooling tower at AWPP is $247 million (Table
2-4). The estimated capital cost is shown in 2017 dollars and represents an indicative screening level cost
estimate, with minimal engineering effort to develop the project design basis. This estimated cost should
not be used for budget planning purposes.
Table 2-4: Estimated Project Costs for Mechanical Draft Cooling Towers
Item Description Cost (2017 Dollars) Total Direct Cost $174,400,000 Equipment $48,800,000 Cooling towers $17,200,000 Installation costs and balance of plant modifications $125,700,000 Total Indirect Cost $20,100,000 Total Direct and Indirect Costs $194,500,000 Project contingency (15%) $29,200,000 Owner cost (5%) $11,200,000 Owner cost contingency (5%) $11,700,000 Total Project Cost $246,600,000
2.2.3.2 Operation and Maintenance Costs Additional annual O&M costs were estimated for the mechanical draft cooling tower at AWPP. The
O&M costs are comprised of two main categories: fixed O&M costs and variable O&M costs. O&M
costs are not inclusive of the entire plant O&M, but are representative of the additional O&M costs for the
operation of added equipment. The O&M impact from the removal of existing equipment (i.e., intake
screens, existing pumps) are not included.
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Fixed O&M costs include additional staffing and general maintenance costs, which are estimated as a
percentage of the capital costs and generally include items such as: electronics; controls; electrical
maintenance and replacements; lighting; heating, ventilation, and air conditioning (HVAC); preventative
maintenance for pumps, valves, and any other equipment; and equipment inspections.
Variable O&M costs include water consumption and chemical treatment for collector well water makeup
to the cooling tower and are based on a 90 percent capacity factor. Additional annual fixed and variable
O&M costs are shown in Table 2-5. O&M costs exclude wastewater treatment and escalation.
Table 2-5: Estimated Cooling Tower Project O&M
O&M Cost Type Cost (2017 Dollars) Additional annual fixed O&M costs $2,746,000 Additional annual variable O&M costs $3,246,000
2.2.3.3 Net Present Value Costs The overall life-cycle (net present value [NPV]) project costs were estimated to be $291 million, based on
7 percent rate of return, a 20-year operation life cycle (after project completion), and 3 percent escalation
for capital and O&M (Table 2-6). The NPV cost is based on capital expenditure occurring in 2020 and
operation after project completion starting 2022. These costs do not include estimated lost energy costs
associated with a reduction in generating capacity resulting from the use of a CCRS system and
construction downtime (assumed six-week outage).
Table 2-6: Total Project Life Cycle Costs
Item Description Cost (2017 Cost) Present value of project capital cost $220,000,000 Present value of annual O&M cost adder $70,600,000 Total Life Cycle Project Cost $290,600,000
2.2.4 Social Costs EPA defines social costs as the “opportunity cost to society of employing scarce resources to prevent the
environmental damage otherwise occurring except for the design and operation of compliance technology
(79 Fed. Reg. 158, 48387).” Social costs can be further be delineated as each of the following:
• Real-Resource Compliance Costs—direct purchase, installation, and operation
• Government Regulatory Costs—monitoring, administration, and enforcement
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• Environmental Externalities—increased fuel cost impacts from energy penalty and proposed
outages and property value, recreation, human health, and increased water consumption impacts.
Real-resource compliance costs result from purchasing, installing, and operating technologies at AWPP.
As the rule notes, “Any outages, downtime, or other impacts to facility net revenue, are included in
compliance costs, while only that portion of lost net revenue that does not accrue to other producers can
be included in social costs (p. 48,428).” Given AWPP’s expected future market conditions, the analysis
specifies that any entrainment reduction technology will be paid for by retained earnings resulting in lost
net revenues (i.e., producer surplus) that are passed on to shareholders as decreased returns. Shareholders
will experience a consumer surplus loss from their decreased returns which the analysis presents as the
quantified metric of social costs resulting from compliance expenditures. The analysis also quantifies the
increased fuel costs from installing and operating the technology. The analysis does not include estimates
of the lost utility associated with the decreased returns because the shareholders no longer have that
money to spend, nor does it estimate the utility loss from the economic impacts resulting from those
decreased expenditures. Therefore, this component of the analysis underestimates social costs.
Government Regulatory Costs are developed from EPA’s estimates in the Final Rule. As presented in the
EPRI’S report titled An Introduction to Social Costs and Resources for 316(b) Entrainment Evaluations
(EPRI 2015, Product Id: 3002006306), there are numerous social costs from environmental externalities
that can result from implementing and operating entrainment technologies. Deciding which of these to
quantify depends on which are relevant for an individual site and the time and resources available to study
them. For this analysis, based on the site’s characteristics and compliance schedule, the environmental
externalities determined to study were the offsite emissions resulting from conversion-based outages and
operation efficiency losses (evaluated in Veritas’ Power System Capacity Loss and Offsite Emissions
Study).
Social costs were estimated for the installation and operation of the two, mechanical draft cooling towers
at AWPP. The social costs include the expected balance sheet cash reserve decrease, the additional,
system-level fuel costs that would be incurred, and the permitting costs. Capital, O&M, and fuel costs
were treated as pre-tax, and total social costs were estimated as the NPV over the time period using
discount rates of 3 and 7 percent.
The estimated social costs for a CCRS retrofit range from $166.9 to 273.0 million depending on the
discount rate used (Table 2-7). The fourth column of Table 2-7 presents the consumer surplus losses from
passing on decreases in balance sheet cash reserves to shareholders as decreased returns. The fifth column
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of Table 2-7 presents increased fuel costs that will be passed on to shareholders as decreased returns.
Appendix B provides the detailed methods and results of the social costs study at AWPP.
Table 2-7: Total Compliance and Social Costs for Mechanical Draft Cooling Towers
Discount Rate
Design, Construction, & Installation
Costsa,b O&M
Costsa,b
Balance Sheet Cash
Reserve Decreasea
Fuel Costsa,b
Permitting Costsb
Total Social
Costsa,b
Annualized Social Costsa
3% $246.6M $6.0M $242.2M $46.6M $75,000 $273.0M $13.7M 7% $246.6M $6.0M $148.1M $46.6M $75,000 $166.9M $8.3M
(a) M = million (b) The engineering, permitting, and fuel costs are undiscounted and in 2017 dollars. The social costs are discounted at
3 and 7 percent.
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3.0 FINE MESH MODIFIED TRAVELING SCREENS
The following provides a comprehensive technical feasibility study and cost evaluations of fine mesh
modified traveling screens.
3.1 Technical Feasibility As required in the Final Rule under §°122.21(r)(10)(i), the following provides an evaluation of the
technical feasibility of this technology.
3.1.1 Description of the Technologies Considered Modified traveling screens are a commercially successful fish collection, handling, and return technology.
Modified traveling screens collect and return impinged organisms to the source waterbody, but they do
not reduce the number of organisms impinged. Modified traveling screens with 3/8-inch mesh do not
reduce entrainment. However, the use of fine mesh screens (< 2-mm) have demonstrated reductions in
entrainment by physically excluding some fish eggs and larvae from being entrained. It should be noted
that organisms that were previously entrained are now physically excluded and impinged on the fine mesh
screens.
This alternative would include the installation of six new traveling screens with a fish handling and return
system at the CWIS. New traveling screens would need to be installed since the existing traveling screens
(six in total) are not suited for retrofitting with buckets. The new screens would be equipped with a
modified bucket system and a low-pressure spray that would gently wash the collected fish out of the
buckets into a separate fish return trough. The return trough would be routed away from the CWIS to
prevent secondary flow circulation and re-impingement. The proposed fish trough discharge could
potentially be located west of the CWIS as shown in Appendix C.
Several features would be considered during the preliminary design of the modified traveling screens and
fish handling and return system, including the following (EPRI, 2015):
• Design flow – Spray wash flow should not be used as the design flow for a fish return because a
large portion of that water may be directed away from the trough. The design flow should be
based on the amount of spray wash flow that is expected in the trough (manufacturer provided)
and any auxiliary flow needed to provide proper hydraulic conditions.
• Combined or separate fish and debris trough – No discernible difference in survival between
combined or separate troughs has been observed. Combined troughs may reduce or eliminate the
need for supplemental flow to increase transport velocity or water depth.
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• Open channel or closed conduit – Open channels are recommended to aid in inspection and
maintenance of the fish return. Covers or grating can be used to cover the return trough if
predation by birds or mammals is a concern. Closed conduit pipes may be needed for part or all
of a return, depending on site-specific conditions.
• Pressurized systems – Open channel flow is recommended when feasible. When a pressurized
fish return is needed, fish-friendly pumps should be used, and rapid pressure changes should be
avoided.
• Flow depth – Water depth in the return should be sufficient to totally immerse organisms. A
minimum water depth of 4 to 6 inches [in.]) should be sufficient for most impingeable-sized
organisms (e.g., juvenile fish).
• Water velocity – Water velocities in the return should be higher than the sustained cruising speed
of the conveyed fish to discourage them from residing in the return system. In general, velocities
between 2 and 12 feet per second (fps) should be sufficient, although the ultimate velocity within
the return system will depend on the target species and site constraints. Site characteristics may
require velocities outside of this range. If velocities exceed 12 fps, special attention to pipe and
joint smoothness must be demonstrated by the design. With velocities less than 2 fps, silt and
sand accumulation could potentially become an issue. Velocities greater than 6.6 fps should be
used to reduce the colonization of veligers (mussel larvae) on piping or return line surfaces.
• Slope – The slope should be sufficient to maintain the desired flow and water depth. Steep
downward slopes and long slopes should be avoided. Small vertical drops (less than 4 feet) are
recommended rather than steep downward slopes. Splash shields are recommended at drop
locations to contain water and small fish.
• Shape and width – A minimum return width of 10 in. and freeboard of 6 in. are recommended for
reducing debris plugging and overtopping. Additional freeboard may be needed at curves or
locations of hydraulic jumps or waves.
• Turn radius – When space allows, long radius turns should be used to encourage smooth passage
of debris; however, laboratory studies have demonstrated no adverse effects of tight radii on fish
survival.
• Materials and coatings – The material selected for the fish return should be as smooth as possible
to reduce potential abrasion of organisms. Suitable materials include fiberglass, wood, plastics,
metal, or coated concrete. However, the design should include an allowance for biofouling
(higher surface roughness coefficient) while maintaining adequate water volume and velocities
within the return system. Covers should be used outdoors to reduce biofouling and predation.
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• Joints and in-trough structures – The inside of the fish return should be smooth with no sharp
edges or protuberances.
• Discharge location – The discharge location should be selected to return organisms back to the
source waterbody under all expected water levels, prevent re-impingement, and prevent
entrainment in the thermal plume.
• Discharge arrangement – Surface, submerged, and free fall discharges can all provide a safe
return. For free fall discharges, the water depth should be 3 feet or 25 percent of the height of the
drop, whichever is greater.
• Obstructions such as baffles, walls, grates, and rocks should not be placed within the area of the
fish return discharge.
• Debris screening – Installation of any debris screening in the fish return could trap collected
organisms and should be avoided. Screening of the debris return line before combining with the
fish return would not be an issue.
• Temperature – The fish return should be designed to prevent icing or excessive heating. Materials
with low thermal conductivity, insulation, or shading can be used to reduce thermal effects.
• Biofouling control – Where attached biofouling organisms are an issue, redundant return lines
provide a fish-friendly means for biofouling control.
The following is a description of the fish handling and return system that would be installed at AWPP.
Appendix C provides example figures of a typical modified traveling screen and the fish handling and
return system at AWPP.
• Each traveling water screen consists of a continuous series of screen baskets fitted with a smooth
top wire mesh screen deck.
• As the baskets are lifted out of the water, floating and suspended debris are collected on the face
of the wire mesh, while aquatic life are directed into the basket’s trough utilizing a fish catching
system. The smooth, flush mounting of the mesh assists with discharge and encourages
deposition of aquatic life in the basket trough.
• As baskets pass over the head shaft assembly, aquatic organisms are gently discharged from the
basket trough into the fish return system with the aid of gentle, low-pressure sprays. The fish
return system consists of a fiberglass trough which returns aquatic life to the downstream side of
the water source. The trough is designed to maintain a minimum of 6 in. of water while the
screens operate. Following removal of the fish, a high-pressure front spray system cleans the
debris from the face of the wire mesh. A rear seal reduces the potential for debris carry-over.
Technical Feasibility and Cost Study Final Fine Mesh Modified Traveling Screens
Alcoa Warrick Power Plant 3-4 Burns & McDonnell
• The capture mechanism is comprised of unique aquatic life survival baskets; these special
purpose baskets are designed solely for capture and retention of aquatic life without degrading
flows and hydraulics in the intake. Baskets with a deep trough enhance survival potential, and the
shape of this trough assists with capture and discharge. The utilization of smooth-top, slotted
opening mesh provides for increased open areas and reduced velocities, and discourages stapling.
• The release mechanism is comprised of the fish sprays and basket-mesh design. The release
mechanism is primarily the large amount of water in the basket trough that spills out at discharge,
providing a smooth unobstructed slide for aquatic life release. The fish spray is low pressure (10-
15 pounds per square inch gage [psig]) and consists of an outside and an inside spray. The outside
spray acts primarily as a sluicing device, keeping the release path inundated with water. The
inside spray aids in removing the aquatic life off the mesh surface, with the use of gravity, and
discharging the aquatic life into the return mechanism.
• The return mechanism consists of a deep trough system designed to return the aquatic life to the
water source. The trough is typically fabricated from fiberglass and has rounded corners. The
trough is sloped to allow for a minimum of 6 in. of water to remain in the trough during
operation. For preliminary design, it was assumed the return trough is 12 in. wide with a slope of
approximately 0.09 ft./ft. The trough will be above grade with tray supports at 10-ft. spacing.
Covers will be installed on the trough where needed to prevent the removal of aquatic life by
outside predators, such as birds or small mammals. The wetland area adjacent to the fish trough
will be rough graded and a gravel roadway will be installed to allow access to the trough for
routine maintenance and inspection. This return location and access roads will cause both
temporary and permanent impacts to the forested areas and adjacent wetland.
• The modified traveling screens would be continually rotated while the plant is in operation, which
represents a change in historical operation of this equipment. Some evaluation on design life
expectancy should be completed prior to selecting the new screen equipment.
If this technology is selected, a more detailed evaluation of the design criteria will be conducted during
the design phase. Design criteria that will be evaluated in more detail will include:
• Overall return dimensions (length, width, slope)
• Radius of turns in the return trough between the AWPP and the point of discharge
• Planned construction materials including types of covers that will be provided
• Expected rate of water flow in the trough
• Depth of water at the point of discharge
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• Height above the water surface for the discharge from the return; including potential extremes in
water elevation (i.e., during floods or extended dry period/drought conditions)
• Proximity to the thermal discharge
• Inspection, cleaning, and monitoring requirements
3.1.2 Discussion of Land Availability Modified traveling screens would be installed in the existing CWIS. Therefore, land availability for the
screens is not an issue. It is assumed the new fish trough will discharge west of the intake structure (see
Appendix C for the potential location). The proposed location of the return discharge considered the
hydraulic zone of influence and thermal discharge as well as selecting a fish return length that minimizes
transport mortality. The return discharge location will be evaluated in further detail during the design
phase (if this technology is selected).
3.1.3 Discussion of Other Available Water Sources Other potential cooling water sources were evaluated in Section 2.1.3. In general, other available water
sources are typically not applicable to the evaluation of fine mesh modified traveling screens because a
once-through cooling water system would continue to be used and the cooling water requirements of
400,000 gpm or 576 MGD would remain the same.
Based on the available aquifer thickness at the site and transmissive aquifer material indicated by the well
logs, a total of 150 vertical wells (producing 3,000 gpm each), or 39 HCWs (producing 15 MGD each)
could yield the required design intake flow requirements of 576 MGD. However, appropriate spacing
between vertical wells to avoid interference drawdown is estimated to be approximately 500 feet and
appropriate spacing between HCWs is estimated to be approximately a quarter mile. This indicates that
appropriately spacing wells through the area will require approximately 9.5 miles of riverbank for the
HCWs and 14.5 miles of riverbank for the vertical wells. Property acquisition and easements for the wells
and associated piping and electrical would be required throughout this area. In addition, due to the
substantial amount of pumping, negative impacts on the pumping levels of surrounding water wells and a
significant water level decline in the aquifer could occur. Given the number of wells required, negative
impacts on surrounding wells and in the aquifer, need for property acquisition or easements, and the
number of environmental clearances and road/utility permits and agreements that would need to be
obtained, the use of wells as an alternate water source for the screening systems that would continue to
use once-through cooling would be excessively expensive to implement, and is considered infeasible.
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Alcoa Warrick Power Plant 3-6 Burns & McDonnell
WWTPs near AWPP do not provide sufficient quantity for once-through cooling. Based on the design
intake flow of 576 MGD at AWPP, the amount of flow reduction using the Newburgh WWTP (4.6 MGD)
would be 0.8 percent. This very low percentage does not warrant the use of this water source and is
considered infeasible.
3.1.4 Factors That Make the Technology Impractical or Infeasible Several factors are necessary to consider in the assessment of whether fine mesh screens are feasible. The
following provides an evaluation of three primary factors (intake flow velocity, head loss, and biological
effectiveness) that influence the feasibility or the ease/difficulty of implementing and operating fine mesh
modified traveling screens. Three screen mesh sizes were evaluated: 0.5, 1.0, and 2.0 mm.
3.1.4.1 Intake Flow Velocity and Head Loss Flow velocity through the screen is an important design consideration for intake screening systems (EPA,
2004). While the approach velocity is more critical to fish impingement, the through-screen velocity is
important in determining how difficult it is for fish to remove themselves from the screen once impinged.
Intake velocity is important because fish formerly entrained will now be impinged on the screens.
Head loss is caused by friction between and constriction of the water flowing through the screens and the
screening material and debris on the screens. For a given pumping rate and overall screen area, reducing
the screen open area as a result of employing a finer mesh or clogging by debris will increase through-
screen velocity, and head loss will increase because friction is proportional to the square of velocity.
Large head losses can lower the water surface elevation at the circulating water pump suction piping to
the point at which pump vortexing and cavitation can occur or even to where the plant can be tripped
offline. Head losses also create hydrostatic forces against the screens which could result in screen failure
when the forces exceed design limits.
Decreasing screen mesh size reduces the effective open area of the mesh because the screen material
occupies an increasing proportion of the screen area. High debris loading and screen clogging, which is
very likely with fine mesh screens at AWPP if not continually rotated, further reduces effective open area
and can have a substantial effect on the through-screen velocities and head loss. The through-screen
velocity and head loss was estimated for the screen mesh sizes of 0.5, 1.0, and 2.0-mm and the existing
mesh size at 0, 25, 50, and 75 percent clogging (Figure 3-1; Figure 3-2). For the purposes of this study, it
was assumed all screens are 10 ft. wide and submerged 31.46 ft. at low water level to match the existing
conditions.
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As effective open area decreased from the 2-mm screen to the 0.5-mm mesh, through-screen velocity
increased. The fine mesh screens would increase the through screen velocities as compared to the existing
screens and are higher than the IM reduction standard (0.5 fps), ranging from 1.1 fps for 2-mm screens to
1.7 fps for 0.5-mm screens at 25 percent clogging (Figure 3-1). It is possible to increase the screen
footprint for smaller mesh sizes in order to reduce through-screen velocities; however, significant
modifications to the existing intake structure would be required which leads to additional costs and outage
time for installation, and reduces the feasibility of the option. Furthermore, the Final Rule does not
require that fine mesh traveling screens meet the 0.5 fps criteria for entrainment mortality.
Figure 3-1: Through-Screen Velocities under Various Debris Loading Conditions
As through-screen velocity increases, so does head loss. The new screens are designed for a static head of
3 feet with a maximum deflection of ¼ inch. Based on existing drawings, the current screen frames have
enough capacity to withstand the additional forces generated by using a finer mesh screen. Over the range
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0% 25% 50% 75%
Velo
city
(fps
)
Percent Clogged
0.5 X 0.5 mm1 X 1 mm2 X 2 mmExisting ScreenEPA Standard
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of clogging evaluated, none of the mesh sizes would exceed the 3-foot static head design limit (Figure
3-2).
Figure 3-2: Head Losses under Various Debris Loading Conditions
Based on the through-screen velocity and head loss calculations, installing the 0.5, 1, or 2 mm fine mesh
screens at AWPP is technically feasible; however, the clean screen, through-screen velocities are higher
than the EPA 0.5 fps criterion and the existing intake screens. The increase in the through-screen
velocities will likely increase IM at AWPP.
3.1.4.2 Biological Effectiveness As mesh sizes are reduced to prevent entrainment, organisms previously entrained become impinged on
the screens (i.e., “converted” from entrainable to impingeable) and are subjected to spray washes and
return along with larger impinged organisms and debris from the screens (EPA, 2014b). The biological
effectiveness of fine mesh modified traveling water screens for reducing IM and entrainment is dependent
upon: 1) the ability of the screens to physically exclude fish eggs and larvae from entering the cooling
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
0.0% 25.0% 50.0% 75.0%
Head
Los
s (in
ches
)
Percent Clogged
0.5 X 0.5 mm1 X 1 mm2 X 2 mmExisting ScreenDesign Limit
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water system; and 2) the post-collection transfer survival of those impinged fish eggs and larvae.
Entrainment reductions from physical exclusion (or retention) and survival on the modified traveling
screens and in the handling and return systems is a function of the species, life stage, and organism size
and could be dependent on several other factors including screen and return system material, screen
rotation speed and frequency, through-screen velocity, return flume velocity, drop height, length of the
fish return, and water quality (EPA, 2014b). In general, fragile life stages and species have higher
mortality than more robust life stages and species. For fine mesh modified traveling screens, the survival
of each species/life stage must be evaluated against the survival that would result if that organism instead
passed through coarse-mesh screens and the circulating water system. For some species/life stages,
impingement on fine-mesh screens can result in higher mortality than if the organism were entrained
through the circulating water system (EPRI, 2012). Two steps were conducted to estimate the biological
effectiveness of fine mesh modified traveling screens at AWPP:
1. Estimate entrainment reductions through retention (the number of fish eggs and larvae
physically excluded by the traveling screens and retained on the screen)
2. Estimate the post-collection survival of those retained fish eggs and larvae
The following discusses the methods used during to estimate retention and post collection survival to
estimate overall biological effectiveness of fine mesh modified traveling screens.
3.1.4.2.1 Entrainment Reductions Through Retention In general, retention of eggs and larvae increases with decreasing screen mesh size and increasing fish
egg width and larval length (EPRI, 2010). Limited data existing on the retention of fish eggs and larvae
on fine mesh modified traveling screens. In lieu of empirical data, the estimated retention of fish eggs and
larvae was assessed using egg diameters and the ratio of larval total length (TL) to head capsule depth
(HCD). Although most of the body parts of fish larvae are soft and easily compressible at the early larval
stages of development when they are susceptible to entrainment, the head capsule has harder cartilage and
bone that is not compressible (Tenera Environmental, 2013). As such, the HCD can be used to represent
the minimum size that larvae could pass through a fine-mesh screen opening. Uncertainty is associated
with this method, however, because the orientation of larvae at the time of contact with the screen may
result in the exclusion of an organism that could physically fit through the mesh (EPRI, 2014b).
Furthermore, this method does not account for the behavioral response to the screens or the swimming
capabilities of the late larval and juvenile life stages. Thus, the HCD method tends to under estimate
retention and overall biological effectiveness.
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As discussed in the Entrainment Characterization Study at AWPP, the most abundant and susceptible
species of fish at AWPP are freshwater drum, Asian carp, carpsucker/buffalo, and herring (Clupeidae
including gizzard shad). Asian carp were excluded from this estimate because it is a non-native, invasive
species. Eggs collected as part of the Entrainment Characterization Study were identified as either
freshwater drum or unidentifiable. Based on the morphometric data on eggs, egg width ranged from 1.0 to
2.0-mm. Therefore, a screen mesh size of 0.5 mm and 1.0-mm would physically exclude 100 percent of
the freshwater drum and unidentifiable eggs. A 2.0-mm screen would physically exclude less than 2
percent of the eggs.
Morphometric data collected for these three taxa collected during AWPP’s Entrainment Characterization
Study and the EPRI (2014) HCD method were used to estimate the retention of larvae using 0.5-, 1.0-,
and 2.0-mm mesh sizes. Linear regressions were determined using the relationship of observed TL to
HCD and then used to interpolate HCDs for fish larvae of a given length. Probabilities of exclusion were
then derived by integrating estimated HCDs and the associated standard deviations under a normal curve.
Probabilities were calculated over a size range (for example 1.0 to 1.9 mm) up to 25 mm in length. The
results of the HCD method are provided in Figures 10-4 to 10-6 for freshwater drum, carpsucker/buffalo,
and herring larvae.
The results of the HCD method indicate the following:
• The 0.5-mm mesh would physically exclude freshwater drum greater than or equal to 3 mm in
length (Figure 3-3). Based on the available morphometric data, 99 percent of the freshwater
larvae would be retained. Carpsucker/buffalo larvae greater than or equal to 7 mm in length
would be physically excluded, or 100 percent (Figure 3-4). Herring larvae greater than or equal to
9 mm in length would be physically excluded, or 100 percent (Figure 3-5).
• The 1.0-mm mesh would physically exclude freshwater drum larvae greater than or equal to 6
mm in length (Figure 3-3). Based on the available morphometric data, greater than 86 percent of
the freshwater drum larvae would be retained. Using the larval data at AWPP, the HCD method
indicates that carpsucker/buffalo larvae less than 10-mm and herring larvae less than 11-mm in
length would not be physically excluded by 1.0-mm mesh screens (Figure 3-4 and Figure 3-5).
Carpsucker/buffalo larvae entrained at AWPP ranged from 7.0- to 8.5-mm in length and herring
larvae ranged from 9.8- to 10.0-mm in length indicating that carpsucker/buffalo and herring
larvae at AWPP would not be excluded using 1.0-mm mesh screens. However, as mentioned, the
HCD method tends to under estimate retention. To be conservative, it is assumed that 40 percent
of carpsucker/buffalo and herring larvae will be retained.
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• The 2-mm mesh would physically exclude freshwater drum greater than or equal to12 mm in
length (Figure 3-3). Based on the available morphometric data, greater than 36 percent of the
freshwater drum larvae would be retained. Based on the available morphometric data, no
freshwater drum were collected that were greater than 12-mm. Using the larval data at AWPP, the
HCD method indicates that carpsucker/buffalo larvae less than 17-mm and herring larvae less
than 16-mm in length would not be physically excluded by 2.0-mm mesh screens (Figure 3-4 and
Figure 3-5). Carpsucker/buffalo larvae entrained at AWPP ranged from 7.0- to 8.5-mm in length
and herring larvae ranged from 9.8- to 10.0-mm in length indicating that carpsucker/buffalo and
herring larvae at AWPP would not be excluded using 2.0-mm mesh screens. However, as
mentioned, the HCD method tends to under estimate retention. To be conservative, it is assumed
that 20 percent of carpsucker/buffalo and herring larvae will be retained.
Therefore, the smaller the mesh size, the higher probability of retention and thus a higher reduction in
entrainment. However, the survival rate of the those previously entrained that are now impinged is
important in evaluating the overall effectiveness of the fine mesh modified traveling screens, as discussed
in the next section below.
Figure 3-3: Probability of Retention of Freshwater Drum Larvae on Fine Mesh Screens at AWPP
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Prob
abili
ty o
f Ret
entio
n
Larval Length (mm)
Probability of Retention (0.5-mm)
Probability of Retention (1.0-mm)
Probability of Retention (2.0-mm)
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Figure 3-4: Probability of Retention of Carpsucker/Buffalo Larvae on Fine Mesh Screens at AWPP
Figure 3-5: Probability of Retention of Herring Larvae on Fine Mesh Screens at AWPP
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Prob
abili
ty o
f Ret
entio
n
Larval Length (mm)
Probability of Retention (0.5-mm)Probability of Retention (1.0-mm)Probability of Retention (2.0-mm)
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Prob
abili
ty o
f Ret
entio
n
Larval Length (mm)
Probability of Retention (0.5-mm)Probability of Retention (1.0-mm)Probability of Retention (2.0-mm)
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3.1.4.2.2 Post Collection Survival and Overall Biological Effectiveness The post collection survival of fish eggs and larvae off 0.5-, 1.0-, and 2.0-mm fine mesh screens was
assessed using the mean annual entrainment estimate at AWPP, egg mortality rates from EPA (2004),
larval entrainment survival rates on fine mesh traveling screens by EPRI (2009; 2010), and impingement
survival of juveniles and adults on conventional modified traveling screens by EPRI (2003).
• Egg mortality was assumed to be 100 percent for entrained eggs and 20 percent for those that
were converted from entrained to impinged. EPA found that nearly 100 percent of eggs were
entrained unless the mesh slot size was less than 2 mm, and mortality of eggs “converted” to
impingement ranged from 20 to 30 percent (2004).
• Larval survival on fine mesh screens was estimated using larval lengths measured during the 2-
year entrainment characterization study at AWPP and survival rates from EPRI (2009, 2010). An
evaluation of fine mesh traveling screens was completed by EPRI at Alden Research Laboratory
from 2007 to 2009. In the EPRI study, the 48-hour post-collection survival of the larvae
converted to impingement off the 0.5 and 1.0-mm fine mesh screens was extremely poor
(generally less than 30 percent regardless of screen type). All of the larvae converted to
impingement were assumed to have the highest survival rate of 30 percent.
• In the EPRI study, the 48-hour post-collection survival of the larvae converted to impingement
off the 2.0-mm ranged from 0 to approximately 60 percent when larval length was less than 12.0
mm and exceeded 90 percent when size exceeded approximately 12.0 mm. Survival of larvae
greater than 12 mm collected off the 2.0-mm screens was likely higher because the larvae
impinged and subsequently collected off the 2.0-mm mesh size were larger and had developed
musculature and some scales, decreasing their sensitivity to impingement and handling stress.
Analyzing the larval length data from the 2-year entrainment characterization study determined
that 96.1 percent of the larvae were less than 12-mm and 3.9 percent of the larvae were greater
than 12-mm. Therefore, all of the larvae converted to impingement were assumed to have the
highest survival rate of 60 percent.
• Juveniles and adults that were formerly entrained will all be impinged. Impingement mortality
was estimated based on species and family specific, extended survival rates on conventional
traveling screens (EPRI, 2003).
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Using the estimated egg and larval retention and mortality assumptions, the overall effectiveness
(reduction in EM) of the 0.5, 1.0, and 2.0-mm fine mesh traveling screens at AWPP is estimated to be 50,
25, and 20 percent, respectively (Table 3-1; Table 3-2; Table 3-3).
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Table 3-1: Estimated Entrainment Reduction using 0.5-mm Fine Mesh Modified Traveling Screens at AWPP
Life Stage / Taxa Size (mm) Exclusion
Point (mm)a
Average Entrainment (2015-2016)
Fraction Physically Excluded
Estimated Annual
Entrainment Converted to Impingement
Estimated Entrainment
Survival
Estimated Entrainment
Mortality
Estimated Impingement
Survival
Estimated Impingement
Mortality Effectiveness
(Percent) Eggs
Freshwater drum 1.25 - 1.5 0.5 2,825,798 1.00 0 2,825,798 0.0 0 0.80b 565,160 80.0
Unidentified eggs 1.25 - 2.0 0.5 2,772,142 1.00 0 2,772,142 0.0 0 0.80 b 554,428 80.0 Subtotal
5,597,940
0 5,597,940
0
1,119,588 80.0
Larvae
Freshwater drum 4.0 - 12.0 >3 159,546,946 0.99 1,595,469 157,951,477 0.0 1,595,469 0.30 c 110,566,034 29.7
Carpsucker/Buffalo 7.0 - 9.0 >7 28,283,322 1.00 0 28,283,322 0.0 0 0.30 c 19,798,326 30.0
Clupeidae (incl. gizzard shad) 7.0 - 12.0 >9 19,339,024 1.00 0 19,339,024 0.0 0 0.30 c 13,537,317 30.0
Other 5.0 - 12.0
60,771,883 1.00 0 60,771,883 0.0 0 0.30 c 42,540,318 30.0 Subtotal
267,941,175
266,345,705
1,595,469
130,364,359 50.8
Juveniles
Catfish
82,961 1.00 0 82,961 0.0 0 0.56 d 36,503 56.0
Cyprinidae (including Notropis, and emerald shiner)
1,749,774 1.00 0 1,749,774 0.0 0 0.67 e 577,425 67.0
Freshwater drum
3,000,316 1.00 0 3,000,316 0.0 0 0.66 f 1,035,109 65.5
Gizzard shad
6,562,810 1.00 0 6,562,810 0.0 0 0.13 g 5,683,393 13.4
Herrings (including Clupeidae and skipjack herring)
8,696,554 1.00 0 8,696,554 0.0 0 0.13 g 7,531,215 13.4
Temperate bass (including striped bass)
498,721 1.00 0 498,721 0.0 0 0.34 h 328,657 34.1
Suckers
20,480 1.00 0 20,480 0.0 0 0.67 i 6,799 66.8
Sunfish/bluegill
21,237 1.00 0 21,237 0.0 0 0.71 j 6,137 71.1
Subtotal
20,632,852
0 20,632,852
0.0
15,205,240 26.3 Total
294,171,967
0 292,576,498
1,595,469
146,689,187 49.6
(a) The exclusion point for eggs is assumed to be the mesh size. The exclusion point for are total length, derived based on an analysis of head capsule depth (HCD) to total length measurements (b) Estimated egg survival in EPA (2004) (c) Estimated larval survival in EPRI (2009, 2010) (d) Average extended survival for Ictaluridae in EPRI (2003) (e) Average extended survival for Cyprinidae EPRI (2003) (f) Average extended survival for Sciaenidae in EPRI (2003) (g) Average extended survival for Clupeidae in EPRI (2003) (h) Average extended survival for Percichthyidae in EPRI (2003) (i) Average extended survival for Catostomidae in EPRI (2003) (j) Average extended survival for Centrarchidae in EPRI (2003)
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Table 3-2: Estimated Entrainment Reduction using 1.0-mm Fine Mesh Modified Traveling Screens at AWPP
Life Stage / Taxa Size (mm) Exclusion
Point (mm)a
Average Entrainment (2015-2016)
Fraction Physically Excluded
Estimated Annual Entrainment
Converted to Impingement
Estimated Entrainment
Survival
Estimated Entrainment
Mortality
Estimated Impingement
Survival
Estimated Impingement
Mortality Effectiveness
(Percent) Eggs Freshwater drum 1.25 - 1.5 1.0 2,825,798 1.00 0 2,825,798 0.0 0 0.80b 565,160 80.0 Unidentified eggs 1.25 - 2.0 1.0 2,772,142 1.00 0 2,772,142 0.0 0 0.80 b 554,428 80.0
Subtotal 5,597,940 0 5,597,940 0 1,119,588 80.0 Larvae Freshwater drum 4.0 - 12.0 >6 159,546,946 0.86 22,336,572 137,210,374 0.0 22,336,572 0.30 c 96,047,262 25.8
Carpsucker/Buffalo 7.0 - 9.0 >10 28,283,322 0.40 16,969,993 11,313,329 0.0 16,969,993 0.30 c 7,919,330 12.0 Clupeidae (including gizzard shad) 7.0 - 12.0 >12 19,339,024 0.40 11,603,414 7,735,610 0.0 11,603,414 0.30 c 5,414,927 12.0
Other 5.0 - 12.0 60,771,883 0.40 36,463,130 24,308,753 0.0 36,463,130 0.30 c 17,016,127 12.0 Subtotal 187,830,268 148,523,703 39,306,566 103,966,592 23.7
Juveniles Catfish 82,961 1.00 0 82,961 0.0 0 0.56 d 36,503 56.0
Cyprinidae (including Notropis, and emerald shiner) 1,749,774 1.00 0 1,749,774 0.0 0 0.67 e 577,425 67.0
Freshwater drum 3,000,316 1.00 0 3,000,316 0.0 0 0.66 f 1,035,109 65.5
Gizzard shad 6,562,810 1.00 0 6,562,810 0.0 0 0.13 g 5,683,393 13.4 Herrings (including Clupeidae and skipjack herring) 8,696,554 1.00 0 8,696,554 0.0 0 0.13 g 7,531,215 13.4
Temperate bass (including striped bass) 498,721 1.00 0 498,721 0.0 0 0.34 h 328,657 34.1
Suckers 20,480 1.00 0 20,480 0.0 0 0.67 i 6,799 66.8
Sunfish/bluegill 21,237 1.00 0 21,237 0.0 0 0.71 j 6,137 71.1
Subtotal 20,632,852 0 20,632,852 0.0 15,205,240 26.3 Total 214,061,061 0 174,754,495 39,306,566 120,291,420 25.4
(a) The exclusion point for eggs is assumed to be the mesh size. The exclusion point for are total length, derived based on an analysis of head capsule depth (HCD) to total length measurements (b) Estimated egg survival in EPA (2004) (c) Estimated larval survival in EPRI (2009, 2010) (d) Average extended survival for Ictaluridae in EPRI (2003) (e) Average extended survival for Cyprinidae EPRI (2003) (f) Average extended survival for Sciaenidae in EPRI (2003) (g) Average extended survival for Clupeidae in EPRI (2003) (h) Average extended survival for Percichthyidae in EPRI (2003) (i) Average extended survival for Catostomidae in EPRI (2003) (j) Average extended survival for Centrarchidae in EPRI (2003)
Technical Feasibility and Cost Study Final Fine Mesh Modified Traveling Screens
Alcoa Warrick Power Plant 3-17 Burns & McDonnell
Table 3-3: Estimated Entrainment Reduction using 2.0-mm Fine Mesh Modified Traveling Screens at AWPP
Life Stage / Taxa Size (mm) Exclusion
Point (mm)a
Average Entrainment (2015-2016)
Fraction Physically Excluded
Estimated Annual Entrainment
Converted to Impingement
Estimated Entrainment
Survival
Estimated Entrainment
Mortality
Estimated Impingement
Survival
Estimated Impingement
Mortality Effectiveness
(Percent) Eggs Freshwater drum 1.25 - 1.5 2.0 2,825,798 0.00 2,825,798 0 0.0 2,825,798 0.80 0 0.0
Unidentified eggs 1.25 - 2.0 2.0 2,772,142 0.02 2,716,699 55,443 0.0 2,716,699 0.80 11,089 1.6
Subtotal 5,597,940
5,542,497 55,443
5,542,497
11,089 0.8 Larvae Freshwater drum 4.0 - 12.0 >12 159,546,946 0.36 102,110,046 57,436,901 0.0 102,110,046 0.60 c 22,974,760 0
Carpsucker/Buffalo 7.0 - 9.0 >10 28,283,322 0.20 22,626,658 5,656,664 0.0 22,626,658 0.60 c 2,262,666 0
Clupeidae (incl. gizzard shad) 7.0 - 12.0 >16 19,339,024 0.20 15,471,219 3,867,805 0.0 15,471,219 0.60 c 1,547,122 0
Other 5.0 - 12.0 60,771,883 0.20 48,617,506 12,154,377 0.0 48,617,506 0.60 c 4,861,751 0 Subtotal 187,830,268 63,093,565 124,736,703 25,237,426 20.2
Juveniles Catfish 82,961 1.00 0 82,961 0.0 0 0.56 d 36,503 56.0
Cyprinidae (including Notropis, and emerald shiner) 1,749,774 1.00 0 1,749,774 0.0 0 0.67 e 577,425 67.0
Freshwater drum 3,000,316 1.00 0 3,000,316 0.0 0 0.66 f 1,035,109 65.5
Gizzard shad 6,562,810 1.00 0 6,562,810 0.0 0 0.13 g 5,683,393 13.4
Herrings (including Clupeidae and skipjack herring) 8,696,554 1.00 0 8,696,554 0.0 0 0.13 g 7,531,215 13.4
Temperate bass (including striped bass) 498,721 1.00 0 498,721 0.0 0 0.34 h 328,657 34.1
Suckers 20,480 1.00 0 20,480 0.0 0 0.67 i 6,799 66.8
Sunfish/bluegill 21,237 1.00 0 21,237 0.0 0 0.71 j 6,137 71.1
Subtotal 20,632,852 0 20,632,852
0.0
15,205,240 26.3 Total 214,061,061 5,542,497 83,781,860
130,279,200
40,453,755 20.2
(a) The exclusion point for eggs is assumed to be the mesh size. The exclusion point for are total length, derived based on an analysis of head capsule depth (HCD) to total length measurements (b) Estimated egg survival in EPA (2004) (c) Estimated larval survival in EPRI (2009, 2010) (d) Average extended survival for Ictaluridae in EPRI (2003) (e) Average extended survival for Cyprinidae EPRI (2003) (f) Average extended survival for Sciaenidae in EPRI (2003) (g) Average extended survival for Clupeidae in EPRI (2003) (h) Average extended survival for Percichthyidae in EPRI (2003) (i) Average extended survival for Catostomidae in EPRI (2003) (j) Average extended survival for Centrarchidae in EPRI (2003)
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3.2 Cost Evaluation As required in the Final Rule under §122.21(r)(10)(iii), the following provides the compliance and social
costs associated with this technology.
3.2.1 Cost Estimate Methodology An indicative screening level cost estimate (AACE Class 4) was developed for replacing the existing
traveling screens with fine mesh modified traveling screens. The estimate was developed using vendor
quotes for major equipment (i.e. screens) and using data from previous projects for the installation and
balance of plant modifications. Indirect and other costs were determined based on recent similar projects,
utilizing percentages as described in the following sections.
3.2.2 Cost Estimate Basis The following sections provide the basis for the fine mesh modified traveling screen cost estimate. The
purpose of the cost estimate basis is to describe the major scope of the cost items shown in the estimate
summaries.
3.2.2.1 Direct Costs Total direct costs account for equipment, material, and labor costs for the project. The following provides
the cost estimate basis for each category summarized in Table 3-4.
Equipment
The equipment supply includes the procurement of all major equipment required for replacing the existing
traveling screens, which includes:
• Six, fine mesh modified traveling screens (10 ft. basket width, 71 ft. well depth)
• High pressure spray pump (one debris removal spray header per screen) and associated
equipment
• Low pressure spray pump (two spray headers per screen – one to spray fish as they pass over the
head sprocket and one to transfer fish from the basket to the return trough) and associated
equipment
• Vertical turbine pumps (2 x 100 percent; 2,500 gpm) to supply makeup water to the fish return
trough
There was not a significant difference in screen equipment pricing for the varying fine mesh sizes of this
magnitude; however, should APGI choose to replace the existing coarse-mesh traveling screens with fine-
mesh screens, there are certain performance and operational impacts that should be considered. For
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Alcoa Warrick Power Plant 3-19 Burns & McDonnell
example, as mesh size decreases, the available open area also decreases (assuming the footprint of the
intake is not altered) which leads to an increase in through-screen velocity which will likely increase
impingement rates at AWPP.
Installation Costs and Balance of Plant Modifications
This cost group includes all labor, rental, receiving, and material costs associated with the installation of
the equipment and balance of plant modifications. Local labor rates were used to adjust costs from recent
Burns & McDonnell projects, while other design parameters were used to adjust costs associated with
quantities and labor productivity. The scope of these costs includes the following:
• Setting/removing stop logs (six bays)
• Installing the fish return trough (approximately 300 linear feet and includes site prep, supports
(above-grade), concrete and deep foundations)
• Demolishing existing trash screens (six total) and debris trough
• Installing piping associated with spray wash and fish return pumps
• Electrical
• Instrumentation and controls
• Miscellaneous
It was assumed that the existing wiring and controls at the intake will be compatible with the new
equipment and that no modification or repair to the existing traveling screen frames would be required.
3.2.2.2 Indirect Costs, Contingency, and Owner Costs The following sections describe indirect costs, project contingency, and Owner costs and contingency for
the fine mesh modified traveling screens.
Indirect Costs
Indirect costs include estimated costs for the following:
• Construction management based on size of the project and recent Burns & McDonnell projects (8
percent of direct costs)
• Engineering based on size of the project and recent Burns & McDonnell projects (12 percent of
direct costs)
• Start-up management and materials (2 percent of direct costs)
All sales taxes and financing fees are excluded from the estimate.
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Project Contingency
Project contingency (25 percent of total direct and indirect costs) was included to cover accuracy of
pricing, commodity estimates, and omissions from the defined project scope. This contingency is not
intended to cover changes in the general project scope nor major shifts in market conditions that could
result in significant increases in contractor margins, major shortages of qualified labor, significant
increases in escalation, or major changes in the cost of money (interest rate on loans).
Owner Costs and Contingency
Costs have been included for traditional Owner’s costs (5 percent of total direct and indirect costs) such
as project support staff, additional operators, outage time, financing, permitting, etc. Owner contingency
(5 percent of total direct and indirect costs) was also included to cover potential change orders that could
occur over the project duration.
3.2.3 Compliance Costs The following provides the compliance costs associated with this technology.
3.2.3.1 Capital Costs The estimated capital cost for replacing the existing traveling screens with six, fine mesh modified
traveling screens is $9.0 million (Table 3-4). All costs are provided in 2017 dollars.
Table 3-4: Estimated Project Costs for Replacement of Existing Screens with Modified Traveling Screens with a Fish Handling and Return System
Item Description Cost (2017 Dollars) Total Direct Cost $5,472,000
Equipment cost $2,595,000 Installation costs and balance of plant modifications $2,877,000
Total Indirect Cost $1,204,000 Total Direct and Indirect Costs $6,676,000 Contingency (25%) $1,670,000 Owner Cost (5%) $340,000 Owner Contingency (5%) $340,000 Total Project Cost $9,026,000
3.2.3.2 Operation and Maintenance Costs O&M costs will vary for each mesh size based on the debris loading and other site-specific conditions.
O&M costs assumed one screen replacement every five years and 2 percent of the direct costs for routine
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Alcoa Warrick Power Plant 3-21 Burns & McDonnell
maintenance for the screens and the fish return system. Annual O&M costs for routine maintenance were
estimated to be approximately $250,000 for each screen mesh size.
3.2.3.3 Net Present Value Costs The overall life cycle (NPV) project costs were estimated to be $10.4 million (2017 dollars), based on 7
percent rate of return, a 20-year operation life cycle (after project completion), 3 percent escalation for
capital, and 3 percent escalation for O&M. For the purposes of this estimate, it was assumed the work can
occur during a typical plant outage, and therefore no outage revenue losses are included in the NPV cost.
The NPV cost is based on capital expenditures occurring in 2020 and operation after project completion
starting in 2020.
3.2.4 Social Costs Social costs were estimated for the installation and operation of fine mesh traveling screens at AWPP.
The social costs include the expected balance sheet cash reserve decrease, the additional, system-level
fuel costs that would be incurred, and the permitting costs. Capital, O&M, and fuel costs were treated as
pre-tax, and total social costs were estimated as the NPV over the time period using discount rates of 3
and 7 percent.
The estimated total social costs for the installation and operation of fine mesh modified traveling screens
at AWPP range from $6.2 to $9.7 million depending upon the discount rate used (Table 3-5). Appendix B
provides the detailed methods and results of the social costs study at AWPP.
Table 3-5: Total Compliance and Social Costs for Fine Mesh Modified Traveling Screens
Discount Rate
Design, Construction, &
Installation Costsa,b
O&M Costsb
Balance Sheet Cash
Reserve Decreasea
Fuel Costsb
Permitting Costsb
Total Social
Costsa,b
Annualized Social Costsb
3% $9.0M $250,000 $9.7M $191,000 $15,000 $9.7M $484,400 7% $9.2M $250,000 $6.1M $191,000 $15,000 $6.2M $308,000
(a) M = million (b) The engineering, permitting, and fuel costs are undiscounted and in 2017 dollars. The social costs are discounted at
3 and 7 percent.
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4.0 FINE MESH CYLINDRICAL WEDGEWIRE SCREENS
The following provides a comprehensive technical feasibility study and cost evaluations of fine mesh
cylindrical wedgewire screens.
4.1 Technical Feasibility As required in the Final Rule under §°122.21(r)(10)(i), the following provides an evaluation of the
technical feasibility of this technology.
4.1.1 Description of the Technologies Considered Cylindrical wedgewire screens are a passive intake system. To achieve the optimal reduction in
impingement and entrainment, the slot size must be small enough to physically exclude the entrainment of
the organisms. Also, a low through-slot velocity should be maintained, and a sufficient ambient current
must be present to aid organisms in bypassing the structure and to remove other debris from the screen
face (EPA, 2004). When appropriate conditions are met, these screens exploit physical and hydraulic
exclusion mechanisms to achieve consistent reductions in impingement (and, as a result, IM) and
entrainment (EPA, 2014b). The typical design consists of wedge-shaped wires or bars welded to an
internal cylindrical frame that is mounted on a central intake pipe, with the entire structure submerged in
the source waterbody.
In general, two alternatives are available to retrofit the existing CWIS to cylindrical wedgewire screens:
1. Mount cylindrical wedgewire screens on collector pipes on the bottom of the waterbody. The
collector pipes are routed back to the CWIS. A wall is constructed at the face of the CWIS, and
the collector pipes would penetrate the wall to transfer water to the existing pumps through the
existing intake bays.
2. Construct a bulkhead wall in the waterbody in front of the existing CWIS, with wedgewire
screens mounted on individual pipes penetrating the wall to transfer water to the impoundment in
front of the existing CWIS, which remains unmodified except for the removal of the screens. This
alternative was not considered further. River data for the Newburgh Lock and Dam indicates that
flood stage is approximately 368 ft. with historic crests above 380 ft. If a bulkhead wall is
constructed, it would need to be built above the historical flood levels in order to prevent aquatic
life and debris from entering the intake system, in addition to modifying the existing concrete
cells which have a top elevation of 365 ft. Based on this information, this alternative was
determined not to be cost effective for AWPP.
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
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The size and number, and thus, feasibility for the cylindrical wedgewire screen arrangement are directly
related to the intake flow requirements, slot size, and desired through slot velocity. In addition, the size of
the screens would be limited by the available water depth outside the intake canal. Based on the intake
rate and available water depth at AWPP, a screen vendor has recommended the use of 96-inch diameter
screens for the fine mesh option. Vendor sizing for various mesh sizes is as provided in Table 4-1. For
fine mesh screens, the number of screens (and therefore total screen length) is increased in order to meet
the velocity requirements for the AWPP intake rate. For this analysis, 0.5, 1.0 and 2.0 mm mesh were
evaluated. The wedgewire screen array at AWPP was designed to have a maximum through-screen design
intake velocity of less than 0.5 fps, thereby minimizing impingement and complying with IM Option 2.
Table 4-1: Vendor Sizing for Cylindrical Wedgewire Screens
Item Description 2-mm Fine
Mesh 1-mm Fine
Mesh 0.5-mm Fine
Mesh Screen diameter (inches) 96 96 96 Screen length (feet) 26.42 27.25 28.00 Number of screens 9 13 20 Total screen length (feet) 237.75 354.25 560.00
The 2-mm mesh cylindrical screens would provide the smallest footprint in the Ohio River. A total of 9
screens are required to meet the intake flow requirements for 2.0 mm slot size and achieve 0.5 fps
through-screen velocity at low river flow (see conceptual sketch in Appendix D). Each screen would be
96 inches in diameter and a length of 26.42 feet. These screens will be connected to a header pipe and two
collector pipes, all of which will be supported by piles. The two collector pipes will be fitted to a steel
plate at the CWIS. An airburst system would be provided to assist in cleaning the screen surfaces. The
airburst system would include an accumulator, distributor system, control systems, and air compressor.
Cleaning cycles would be initiated automatically with a timer or differential head sensor. In addition, the
wedgewire screens would include a coating or alloy material to inhibit biofouling.
If this technology is selected for further consideration at AWPP, APGI will need to contact the U.S. Army
Corps of Engineers (USACE) and U.S. Coast Guard to discuss the feasibility of permitting this
installation. These agencies may not allow the installation of this submerged CWIS on the Ohio River
because of conflicts with navigation and recreational boating, or may have additional requirements that
could impact the CWIS design.
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Alcoa Warrick Power Plant 4-3 Burns & McDonnell
4.1.2 Discussion of Land Availability Land availability for fine mesh cylindrical wedgewire screens is not typically an issue because the major
equipment, such as the screens, are located in the source water body. The only land-based equipment
includes the air backwash system controls, compressors and air receivers, which are sometimes housed in
an individual equipment building. At AWPP, the equipment would likely be housed inside the
maintenance building located behind the CWIS (Appendix D).
4.1.3 Discussion of Other Available Water Sources Other potential cooling water sources were evaluated in Section 2.1.3 and 3.1.3. In general, other
available water sources are typically not applicable to the evaluation of cylindrical wedgewire screens at
AWPP because a once-through cooling water system would continue to be used. The cooling water
requirements of 400,000 gpm or 576 MGD of water would remain the same.
Based on the available aquifer thickness at the site and transmissive aquifer material indicated by the well
logs, a total of 150 vertical wells (producing 3,000 gpm each), or 39 HCWs (producing 15 MGD each)
could yield the required design intake flow requirements of 576 MGD. However, appropriate spacing
between vertical wells to avoid interference drawdown is estimated to be approximately 500 feet and
appropriate spacing between HCWs is estimated to be approximately a quarter mile. This indicates that
appropriately spacing wells through the area will require approximately 9.5 miles of riverbank for the
HCWs and 14.5 miles of riverbank for the vertical wells. Property acquisition and easements for the wells
and associated piping and electrical would be required throughout this area. In addition, due to the
substantial amount of pumping, negative impacts on the pumping levels of surrounding water wells and a
significant water level decline in the aquifer could occur. Given the number of wells required, negative
impacts on surrounding wells and in the aquifer, need for property acquisition or easements, and the
number of environmental clearances and road/utility permits and agreements that would need to be
obtained, the use of wells as alternate water source for the required volume would be excessively
expensive to implement, and is considered infeasible.
WWTPs near AWPP do not provide sufficient quantity for once-through cooling. Based on the design
intake flow of 576 MGD at AWPP, the amount of flow reduction using the Newburgh WWTP (4.6 MGD)
would be 0.8 percent. This very low percentage does not warrant the use of this water source and is
considered infeasible.
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4.1.4 Factors That Make the Technology Impractical or Infeasible Several factors were considered in the assessment of whether fine mesh cylindrical wedgewire screens are
feasible. The following are primary factors that would influence the feasibility or the ease/difficulty of
implementing and operating fine mesh cylindrical wedgewire screens:
4.1.4.1 Engineering and Operational Challenges The number of screens required and the location of the screen array on the collector pipes pose numerous
engineering and operational challenges.
• Navigational hazards to commercial and recreational boating.
• Screen damage from commercial vessels would require screen replacement at unknown intervals.
• Screen damage from commercial vessels could occur, thereby impacting the ability to obtain
sufficient cooling water.
• Significant permitting difficulties would need to be overcome.
• Debris loading and biofouling would clog screens and increase slot velocity, reducing screen
effectiveness in reducing IM and EM.
• Construction of the wedgewire screens would impact AWPP operations and processes and
shutdown AWPP for an estimated 3 weeks. A substantial shutdown period would be required
even if the construction coincided with a scheduled shutdown.
• Extensive site preparation (potential dredging).
• Maintenance would be highly problematic due to debris loading, biofouling, and winter icing.
• Impacts to the Ohio River bottomlands would occur.
The significant footprint of the screens in the Ohio River and associated permitting are the most critical
factors at AWPP. The screens, located outside the existing canal, will pose navigational hazards to
commercial and recreational boating, and would require a USACE nationwide permit and include
USACE’s and U.S. Coast Guard’s review and approval. The 0.5-, and 1.0-mm mesh sizes are considered
to be infeasible because the they require too large of a footprint in the Ohio River, encroach on the
navigation channel and interfere with commercial boating, and would likely not be permitted by the
USACE. The number of screens required to have a maximum through-screen velocity of 0.5 fps was 13
for 1.0-mm slot width, and 20 for 0.5-mm slot width. It is likely that only the 2.0-mm slot width would
potentially be feasible but even that size required 9 screens. Also, the USACE would be very unlikely to
agree to the installation of a bulkhead wall, or permanent construction of these screens beyond the face of
the existing CWIS due to concerns with interference with navigation, and future channel dredging
operations.
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Although an air backwash system would be provided in an attempt to clean the screen surfaces, and the
wedgewire screens would include a coating or alloy material to inhibit biofouling, the backwash system
and coating is not expected to eliminate the debris loading at AWPP; therefore, debris loading could be
problematic and inhibit the wedgewire screens from operating properly. Debris at the AWPP consists of
driftwood, plastic trash, tires, corn stalks, and grass and occurs during flooding. Currently, the trash rake
is operated during flooding when large amounts of drift wood are pulled into the intake. The existing
traveling screens are protected by the trash rake; however, the cylindrical wedgewire screens would be
susceptible damage by this large debris because they will be located outside the canal. Also, any reduction
in the effective open area of the screens would increase through-slot velocities and potentially increase
impingement and entrainment from clean conditions.
4.1.4.2 Estimated Biological Effectiveness When appropriate conditions are met, cylindrical wedgewire screens exploit physical and hydraulic
exclusion mechanisms to achieve reductions in impingement (and, as a result, IM) and entrainment (EPA,
2014b). Cylindrical wedgewire performance data from several installations, as well as laboratory
evaluations, suggest a strong potential to reduce impingement impacts when certain design and
construction criteria are satisfied (EPA, 2014b). Data from some studies have shown reductions in
impingement of near 100 percent. In-situ observations have shown that impingement is virtually
eliminated using wedgewire screens (Hanson, 1981; Lifton, 1979; Browne et al., 1981).
Several field and laboratory studies of fine slot width cylindrical wedgewire screens have been completed
to evaluate their effectiveness in reducing entrainment (Table 4-2). The overall effectiveness of
wedgewire screens varied depending on biological (species, morphology, size) and engineering (slot
width and velocities) parameters. The following are general conclusions based on the observed
differences between ichthyoplankton densities entrained through an open (control) port and the test
screens:
• Entrainment densities decreased with a smaller slot width.
• Slot velocities tested (0.5 and 1.0 fps) did not have a significant effect on entrainment density.
• Larval entrainment densities in both control (no intake screen) and test (with screen) conditions
typically increased as ambient velocity increased, whereas egg entrainment densities were
unaffected by ambient velocity.
• Larval entrainment density decreased with larval length.
• For species with larger head widths, the difference between control and test entrainment densities
was greater.
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Table 4-2: Field and Laboratory Egg and Larvae Exclusion Rates Using Wedgewire Screens
Facility and Location
Wedgewire Slot Size
(mm)
Percentage of Egg Exclusion
(all species)
Percentage of Larval Exclusion
(all species) Referencea Test Facility, Gwynns Island, VA 0.5 19 – 87 58 – 72 EPRI, 2006b Test Facility, Sakonnet River, RI 0.5 92 – 99 72 – 82 EPRI, 2005 Test Facility, Portage River, OH 0.5 93 – 98 NA EPRI, 2005 Test Facility, Brooklyn, NY 0.5 91 NA Henderson et
al., 2003 Test Facility, Gwynns Island, VA 1.0 12 36 – 53 EPRI, 2006b Test Facility, Sakonnet River, RI 1.0 8 – 27 9 – 18 EPRI, 2005 Test Facility, Portage River, OH 1.0 17 – 96 NA EPRI, 2005 Chalk Point Steam Electric Station, Aquasco, MD
1.0 NA 80 Weisberg et al., 1987
Carrol County Station, Mississippi River, IL
1.0 77 74 Otto et al., 1981
Oyster Creek Nuclear Generating Station, Forked River, NJ
1.0 93 93 Browne et al., 1981
Seminole Generating Station, St. John River, FL
1.0 NA 99 EPA, 2004
Laboratory Study 1.0 NA 65 Hanson, 1981 Laboratory Study 1.0 98 96 Hanson et al.,
1977 Oyster Creek Nuclear Generating Station, Forked River, NJ
2.0 92 92 Browne et al., 1981
J. H. Campbell Plant Units 1 and 2, Lake Michigan, MI
2.0 67 84 Zeitoun et al., 1981
Chalk Point Steam Electric Station, Aquasco, MD
2.0 NA 80 Weisberg et al., 1987
Seminole Generating Station, St. John River, FL
2.0 NA 62 EPA, 2004
Chalk Point Steam Electric Station, Aquasco, MD
3.0 NA 80 Weisberg et al., 1987
(a) Full references available in the Literature Cited chapter of this document.
EPRI conducted field evaluations of fine slot width wedgewire screens to examine entrainment rates of
naturally occurring fish species and life stages at three sites with unique hydraulic and environmental
conditions (EPRI, 2005; EPRI, 2006b). A field evaluation was completed at the mouth of the Portage
River (EPRI, 2005). This site was considered representative for AWPP because the freshwater river
species used in the study were similar to, or the same as those entrained at AWPP, including freshwater
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drum and shad (Clupeidae spp.). Testing was conducted daily in May and June 2004. For eggs, control
entrainment densities were 93 percent greater than test entrainment densities for all test conditions except
for the slot width of 1.0 mm and slot velocity of 1.0 fps (Table 4-3). The 0.5-mm screen significantly
reduced the entrainment of eggs by 98 percent at slot velocities of 0.5 fps and 93 percent at slot velocities
of 1.0 fps. The difference among these test conditions was likely the result of extrusion of eggs through
the larger slots at a higher velocity. A 96 percent reduction at 0.5 fps with the 1.0-mm screen was
observed; however, the reduction of egg entrainment at 1.0 fps with the 1.0-mm screen was only 17
percent.
Table 4-3: Mean Density and Standard Deviation of Eggs Collected in Ambient, Control, and Test Samples
Slot Width (mm)
Slot Velocity
(fps)
Mean Number of Eggs Entrained per 100 m3 (Standard Deviation)
Control-Treatment
Percent Differencea Ambient Control Test
0.5 0.5 72.3 (130.2) 45.1 (81.5) 1.1 (3.1) 97.5 (7)b 1.0 91.5 (199.8) 42.0 (81.0) 2.8 (4.3) 93.2 (10)b
1 0.5 74 (118.5) 102.9 (200.0) 4.5 (5.8) 95.7 (10)c 1.0 737.7 (1,806.4) 117.2 (224.1) 97.1 (195.5) 17.1 (9)
Source: EPRI, 2005 (a) Calculated as [(control density minus test density) divided by control density]. Positive values indicate lower densities in test samples. (b) Indicates a statistically significant difference between test and control densities (p < 0.05). (c) p = 0.06
The results for larval exclusion were highly variable, depending upon slot size, slot velocity, and
morphology. For carp (Cyprinus spp.), a significant difference between test and control densities was
found for the 1.0 mm screen at a slot velocity of 1.0 fps. No significant differences between test and
control densities were observed in any of the other test conditions. For shad larvae (including gizzard
shad and alewife), a 98 percent reduction in entrainment was observed for the 0.5-mm screen at a slot
velocity of 0.5 fps for fish between 7 and 9 mm long (Table 4-4). The 1.0-mm screen with a slot velocity
of 1.0 fps only produced a 47 percent reduction in entrainment of shad larvae between 4 and 6 mm long.
For freshwater drum, there were no significant reductions in entrainment for any test conditions despite
the large differences between the treatment and control densities. At a slot velocity of 0.5 and 1.0 fps, a
96 percent reduction in entrainment was observed for a slot size of 0.5 mm. A 72 percent reduction was
observed for a slot size of 1.0 mm at a slot velocity of 1.0 fps. For temperate basses (Morone spp.), the
percent difference between test and control densities was greater than 65 percent for all test conditions.
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
Alcoa Warrick Power Plant 4-8 Burns & McDonnell
Table 4-4: Mean Density and Standard Deviation of Freshwater Fish Larvae Collected in Ambient, Control, and Test Samples
Slot Width (mm)
Slot Velocity
(fps)
Larval Length (mm)
Mean Number of Larvae Entrained per 100 m3 Control-Treatment
Percent Differencea
(Standard Deviation) Ambient Control Test
Carp (Cyprinus spp.) 0.5 0.5 NA 0.3 (0.9) 2.2 (5.6) 2.7 (7.2) -22.1 (7)
1 NA 0.0 (0.0) 1.5 (2.9) 1.1 (1.5) 22.3 (6) 1 0.5 NA 3.6 (7.4) 1.3 (2.5) 2.1 (3.7) -65.5 (6)
1 NA 12.4 (25.2) 6.0 (9.3) 2.7 (5.1) 54.3 (7)b Freshwater drum
0.5 0.5 NA 1.6 (4.2) 2.5 (5.5) 0.1 (0.2) 96.4 (4) 1 NA 43.1 (131.5) 14.2 (36.4) 0.6 (1.6) 95.9 (4)
1 0.5 NA 19.7 (52.0) 0.0 (0.0) 0.1 (0.3) N/Ac 1 NA 199.3 (549.6) 9.9 (19.9) 2.8 (5.5) 71.7 (2)
Shad (Clupeidae spp.) 0.5 0.5 ≤ 3 46.4 (83.5) 51.6 (91.6) 59.6 (127.2) -15.5 (9)
4 – 6 662.5 (884.2) 88.2 (62.4) 57.1 (94.4) 35.2 (8) 7 – 9 535.1 (1,017.7) 8.4 (9.5) 0.1 (0.4) 98.2 (5)b ≥ 10 28.4 (69.5) 0.0 (0) 0.0 (0) N/Ac All 1,272.6 (1,931.4) 148.2 (148.6) 116.9 (220.3) 21.1 (9)
1 ≤ 3 182.3 (357.5) 72.7 (98.8) 63.9 (90.6) 12.1 (10) 4 – 6 822.3 (1,591.5) 138.4 (122.2) 53.1 (50.4) 61.6 (10)b 7 – 9 373 (790.9) 28.8 (51.6) 6.3 (9.9) 78.1 (6) ≥10 10.6 (24.9) 4.5 (11.2) 0 (0) 100 (2) All 1,388.3 (2,365.2) 244.4 (182.4) 123.3 (125.3) 49.5 (10)b
1 0.5 ≤ 3 83.4 (139.2) 97.2 (92.4) 54.4 (75.9) 44.0 (7) 4 – 6 1,902.5 (3,036.2) 497 (1,061.2) 455.9 (1,119.4) 8.3 (7) 7 – 9 237.1 (323.2) 20.7 (39.2) 0.8 (1.5) 96.1 (5) ≥ 10 3.9 (9.3) 0.0 (0) 0.0 (0) N/Ac All 2,226.9 (3,304) 614.9 (1,109.7) 511.1 (1,097.7) 16.9 (7)
1 ≤ 3 158.7 (158.6) 283.9 (371.9) 382.4 (574.5) 34.7 (9) 4 – 6 937.9 (1,367.7) 269.8 (230.9) 142.9 (168.9) 47 (9)b 7 – 9 56.3 (56.4) 17.6 (26.1) 5.6 (11.2) 68 (4) ≥ 10 4.2 (8.4) 0.0 (0) 0.0 (0) N/Ac All 1,157.2 (1,320.3) 571.3 (533.5) 530.9 (628.3) 7.1 (9)
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
Alcoa Warrick Power Plant 4-9 Burns & McDonnell
Slot Width (mm)
Slot Velocity
(fps)
Larval Length (mm)
Mean Number of Larvae Entrained per 100 m3 Control-Treatment
Percent Differencea
(Standard Deviation) Ambient Control Test
Temperate basses (Morone spp.) 0.5 0.5 NA 15.3 (25.6) 1.6 (2.3) 0.5 (1.1) 67.7 (6)
1 NA 15.2 (40.3) 0.7 (1.5) 0.2 (0.5) 65.7 (4) 1 0.5 NA 38.2 (83.9) 0.4 (1.2) 0.0 (0.0) N/Ac
1 NA 21.6 (35.9) 0.4 (0.8) 0.0 (0.0) 100.0 (2) Source: EPRI, 2005 (a) Calculated as [(control density minus test density) divided by control density]. Positive values indicate lower densities in test samples. (b) Indicates a statistically significant difference between test and control densities (p < 0.05). (c) Insufficient data for meaningful comparison.
Based on the highly variable laboratory and in-situ results for the fish species, the estimated effectiveness
of 0.5-, 1.0-, and 2.0-mm fine slot width screens at AWPP is uncertain. In general, the smaller the mesh
size, the higher the probability to physically exclude the eggs and larvae which results in higher
effectiveness. The benefit of the cylindrical wedgewire screens over the modified traveling screens is that
the eggs and larvae formerly entrained that are now impinged could potentially be removed off the
screens by the ambient river sweeping velocity or blown off by the airburst system.
The use of 0.5-mm mesh cylindrical wedgewire screens at a design through-screen velocity of 0.5 fps at
AWPP would reduce entrainment more than the other two screen slot sizes. Based on the results from
EPRI (2005), the use of 0.5-mm mesh cylindrical wedgewire screens could potentially reduce egg and
larval entrainment by 98 and 96 percent, respectively. The use of 1.0-mm fine mesh at a design through-
screen velocity of 0.5 fps at AWPP would reduce egg and larval entrainment by 96 and 72 percent,
respectively. The biological effectiveness of using 2.0-mm fine mesh at a design through-screen velocity
of 0.5 fps at AWPP is even more difficult to estimate because of the lack of recent effectiveness data and
data on the potential for eggs and larvae to be extruded through the larger slot width. Based on
morphometric data collected as part of the 2-year Entrainment Characterization Study (not accounting for
hydraulic mechanisms of cylindrical wedgewire screens), the 2-mm mesh would not physically exclude
freshwater drum eggs and freshwater drum larvae less than 17 mm in length (Figure 3-3), and
carpsucker/buffalo and herring larvae less than 12-mm in length (Figure 3-5; Figure 3-5). However, data
on 2-0-mm fine mesh cylindrical wedgewire screens indicate egg entrainment reductions from 67 to 92
percent and larval entrainment reductions from 62 to 84 percent (see Table 4-2). Given the size of the fish
eggs and larvae at AWPP, entrainment reductions using 2.0-mm fine mesh screens is anticipated to be on
the lower side of these ranges (67 percent for eggs and 64 percent for larvae). Using the mean entrainment
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
Alcoa Warrick Power Plant 4-10 Burns & McDonnell
estimates at AWPP (excluding Asian carp) and the aforementioned egg and larval reductions, the overall
entrainment reduction at AWPP using 2.0-mm fine mesh cylindrical wedgewire screens is 65 percent
(Table 4-5).
Table 4-5: Estimated Entrainment Reduction using 2.0-mm Fine Mesh Cylindrical Wedgewire Screens at AWPP
Life Stage Mean Annual Entrainment
Estimated Percent
Reduction
Estimated New
Entrainment Eggs 5,597,940 67a 1,847,320 Larvae 241,737,797 62b 91,860,363
Juveniles 20,605,438 100c 0 Adults 0 100c 0 Total 267,941,175 93,707,683 Percent Entrainment Reduction 65.0
(a) Estimated egg exclusion in Zeitoun et al. (1981) (b) Estimated larval exclusion in EPA (2004) (c) Assumed all juveniles and adults would be physically excluded based on size.
4.2 Cost Evaluation As required in the Final Rule under §°122.21(r)(10)(iii), the following provides the compliance and social
costs associated with this technology.
4.2.1 Cost Estimate Methodology An indicative screening level cost estimate (AACE Class 4) was developed for replacing the existing
traveling screens with fine mesh cylindrical wedgewire screens. The estimate was developed using vendor
quotes for major equipment (i.e. screens) and using data from previous projects for the installation and
balance of plant modifications. Indirect and other costs were determined based on recent similar projects,
utilizing percentages as described in the following sections.
4.2.2 Cost Estimate Basis The following sections provide the basis for the cylindrical screen estimate. The purpose of the estimate
basis is to describe the major scope of the cost items shown in the estimate summaries.
4.2.2.1 Direct Costs Total direct costs account for equipment, material, and labor costs for the project. The following provides
the cost estimate basis for each category summarized in Table 4-6.
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
Alcoa Warrick Power Plant 4-11 Burns & McDonnell
Equipment
The equipment supply includes the procurement of all major equipment required for replacing the existing
traveling screens, which includes:
• Cylindrical wedgewire screens and support structure
• Airburst system (includes accumulator, distributor system, control systems, air compressor and
piping to each screen drum)
Installation Costs and Balance of Plant Modifications
This cost group includes all labor, rental, receiving, and material costs associated with the installation of
the equipment and balance of plant modifications. Local labor rates were used to adjust costs from recent
Burns & McDonnell projects, while several other design parameters were used to adjust costs associated
with quantities and labor productivity. The scope of these costs includes the following:
• Setting stop logs (six bays)
• Demolishing existing bar screen (six total)
• Supplying/installing buoys
• Installing piles for intake pipes
• Installing blanking plate for intake structure
• Installing piping associated with intake, airburst system, and warm water line
• Electrical
• Instrumentation and controls
• Miscellaneous
It was assumed that the existing wiring and controls at the intake will be compatible with the new
equipment.
4.2.2.2 Indirect Costs, Contingency, and Owner Costs The following summarizes the indirect costs, contingency, and owner costs for fine mesh cylindrical
wedgewire screens.
Indirect Costs
Indirect costs include estimated costs for the following:
• Construction management based on size of the project and recent Burns & McDonnell projects (8
percent of direct costs)
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
Alcoa Warrick Power Plant 4-12 Burns & McDonnell
• Engineering based on size of the project and recent Burns & McDonnell projects (12 percent of
direct costs)
• Start-up management and materials (2 percent of direct costs)
All sales taxes and financing fees are excluded from the estimate.
Project Contingency
Project contingency (25 percent of total direct and indirect costs) was included to cover accuracy of
pricing, commodity estimates, and omissions from the defined project scope. This contingency is not
intended to cover changes in the general project scope nor major shifts in market conditions that could
result in significant increases in contractor margins, major shortages of qualified labor, significant
increases in escalation, or major changes in the cost of money (interest rate on loans).
Owner Costs and Contingency
Costs have been included for traditional Owner’s costs (5 percent of total direct and indirect costs) such
as project support staff, additional operators, outage time, financing, permitting, etc. Owner contingency
(5 percent of total direct and indirect costs) was also included to cover potential change orders that could
occur over the project duration.
4.2.3 Compliance Costs The following provides the compliance costs associated with this technology.
4.2.3.1 Capital Costs The estimated capital cost for the fine slot width cylindrical wedgewire screens ranged from $16.5 to
$35.8 million (Table 4-6). All costs are provided in 2017 dollars. A conceptual design was prepared for
the 2-mm screen estimate and was used as a base to build up costs for the 1-mm and 0.5-mm options.
This cost represents an indicative screening level cost estimate, with minimal engineering effort to
develop the project design basis, and this cost should not be used for budget planning purposes.
Table 4-6: Estimated Project Costs for Fine Mesh Cylindrical Wedgewire Screens
Item Description Cost (2017 Dollars)
0.5-mm 1-mm 2-mm Total Direct Cost $21,760,000 $14,400,000 $10,010,000
Equipment cost $10,270,000 $6,540,000 $4,470,000 Installation costs and balance of plant modifications $11,490,000 $7,860,000 $5,540,000
Total Indirect Cost $4,788,000 $3,168,000 $2,203,000 Total Direct and Indirect Costs $26,548,000 $17,568,000 $12,213,000
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
Alcoa Warrick Power Plant 4-13 Burns & McDonnell
Item Description Cost (2017 Dollars)
0.5-mm 1-mm 2-mm Contingency (25%) $6,640,000 $4,400,000 $3,060,000 Owner Cost (5%) $1,330,000 $880,000 $620,000 Owner Contingency (5%) $1,330,000 $880,000 $620,000 Total Project Cost $35,848,000 $23,728,000 $16,513,000
4.2.3.2 Operation and Maintenance Costs O&M costs will vary for each mesh size based on the debris loading and other site-specific conditions.
Annual O&M costs for routine maintenance (including annual diver inspections) were estimated to be as
follows assuming one screen replacement every five years and 0.25 percent of the equipment costs for
routine maintenance. O&M costs are estimated to range from $170,000 to $210,000 (Table 4-7).
Table 4-7: Estimated O&M for Fine Mesh Cylindrical Wedgewire Screen
Item Description Cost (2017 dollars)
0.5-mm 1-mm 2-mm Annual O&M $210,000 $190,000 $170,000
4.2.3.3 Net Present Value Costs The overall life-cycle (NPV) project costs is estimated to range from $15.9 to $32.6 million (Table 4-8).
NPV costs were estimated based on 7 percent rate of return, a 20-year operation life cycle (after project
completion), 3 percent escalation for capital, and 3 percent escalation for O&M. For the purposes of this
estimate, it was assumed the work can occur during a 3-week outage, and therefore outage revenue losses
are included in the NPV cost. The NPV cost is based on capital expenditures occurring in 2020 and
operation after project completion starting in 2020.
Table 4-8: Total Project Life Cycle Costs for Fine Mesh Cylindrical Wedgewire Screens
Item Description Cost (2017 dollars)
0.5-mm 1-mm 2-mm Net present value (NPV) 32,590,000 22,190,000 15,840,000
4.2.4 Social Costs Social costs were estimated for the installation and operation of fine mesh cylindrical wedgewire screens
at AWPP. The social costs include the expected balance sheet cash reserve decrease, the additional,
system-level fuel costs that would be incurred, and the permitting costs. Capital, O&M, and fuel costs
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
Alcoa Warrick Power Plant 4-14 Burns & McDonnell
were treated as pre-tax, and total social costs were estimated as the NPV over the time period using
discount rates of 3 and 7 percent.
The estimated total social costs for the installation and operation of fine mesh cylindrical wedgewire
screens at AWPP range from $8.7 to $27.4 million depending on the wedgewire slot size as well as the
discount rate used (Table 4-9). Appendix B provides the detailed methods and results of the social costs
study at AWPP.
Technical Feasibility and Cost Study Final Fine Mesh Cylindrical Wedgewire Screens
Alcoa Warrick Power Plant 4-15 Burns & McDonnell
Table 4-9: Total Compliance and Social Costs for Fine Mesh Cylindrical Wedgewire Screens
Discount Rate
Screen Mesh Size
Design, Construction, &
Installation Costsa,b
O&M Costsb
Balance Sheet Cash
Reserve Decreasea
Fuel Costsb
Permitting Costsb
Total Social Costsa,b
Annualized Social Costsb
3% 0.5-mm $35.8M $210,000 $27.8M $191,000 $35,000 $27.4M $1.4M 1.0-mm $23.7M $190,000 $19.1M $191,000 $35,000 $18.9M $945,000 2.0-mm $16.5M $170,000 $13.8M $191,000 $35,000 $13.7M $685,000
7% 0.5-mm $35.8M $210,000 $17.6M $191,000 $35,000 $17.4M $871,000 1.0-mm $23.7M $190,000 $12.1M $191,000 $35,000 $8.9M $444,000 2.0-mm $16.5M $170,000 $8.7M $191,000 $35,000 $8.7M $435,000
(a) M = million (b) The engineering, permitting, and fuel costs are undiscounted and in 2017 dollars. The social costs are discounted at 3 and 7 percent.
Technical Feasibility and Cost Study Final Water Reuse and Alternate Sources of Cooling Water
Alcoa Warrick Power Plant 5-1 Burns & McDonnell
5.0 WATER REUSE AND ALTERNATE SOURCES OF COOLING WATER
The following provides a comprehensive technical feasibility study and cost evaluations of water reuse
and alternate sources of cooling water.
5.1 Technical Feasibility As required in the Final Rule under §°122.21(r)(10)(i), the following provides an evaluation of the
technical feasibility of this technology.
5.1.1 Description of the Operational Measure Water resource and alternate sources for cooling water were evaluated in Section 2.1.3, 3.1.3, and 4.1.3.
Groundwater was identified as a potential alternate water source for makeup water to the cooling tower.
Groundwater and WWTPs were not feasible for technologies that will continue to use a once-through
cooling water system, such as fine mesh traveling screens and cylindrical wedgewire screens. Based on
the available aquifer thickness at the site and transmissive aquifer material indicated by the well logs, a
total of 150 vertical wells (producing 3,000 gpm each), or 39 HCWs (producing 15 MGD each) could
yield the required design intake flow requirements of 576 MGD and require approximately 9.5 miles of
riverbank for the HCWs and 14.5 miles of riverbank for the vertical wells. Given the number of wells
required, negative impacts on surrounding wells and in the aquifer, need for property acquisition or
easements, and the number of environmental clearances and road/utility permits and agreements that
would need to be obtained, the use of wells as an alternate water source for the screening systems that
would continue to use once-through cooling would be excessively expensive to implement, and is
considered infeasible.
WWTPs near AWPP do not provide sufficient quantity for once-through cooling. The amount of flow
reduction using the closest WWTP (Newburgh WWTP (4.6 MGD)) would be 0.8 percent. This very low
percentage does not warrant the use of this water source, and is considered infeasible.
5.1.2 Discussion of Land Availability Land availability to utilize other available water resources is dependent upon the distance between the
facility to the source, the characteristics and land use in which the supply and return lines are routed, and
the density of existing underground and above-grade utilities. The use of groundwater or WWTPs for a
once through cooling system is impractical and expensive, given required area of 9.5 to 14.5 miles of
riverbank. The use of groundwater or WWTPs for a once through cooling system is impractical and
expensive given the relatively small volume of water that could be used for cooling purposes.
Technical Feasibility and Cost Study Final Water Reuse and Alternate Sources of Cooling Water
Alcoa Warrick Power Plant 5-2 Burns & McDonnell
5.1.3 Discussion of Other Available Water Sources Other available water sources in the vicinity of AWPP were discussed in Sections 2.1.3, 3.1.3, and 4.1.3.
5.1.4 Factors That Make the Technology Impractical or Infeasible Factors that make water reuse and alternate sources of cooling water impractical or infeasible were
discussed in Sections 2.1.3, 3.1.3, and 4.1.3. Groundwater was identified as a potential alternate water
source for makeup water to the cooling tower. Groundwater and WWTPs were not feasible for
technologies that will continue to use a once-through cooling water system, such as fine mesh traveling
screens and cylindrical wedgewire screens.
5.2 Cost Evaluations Compliance costs and social costs were not prepared since this operational measure was considered
infeasible.
Technical Feasibility and Cost Study Final Summary
Alcoa Warrick Power Plant 6-1 Burns & McDonnell
6.0 SUMMARY
Per the Final Rule requirements, the technical feasibility of CCRS, fine mesh screens with a mesh size of
2 mm or smaller, and water reuse or alternate sources of cooling water were evaluated at AWPP.
Mechanical draft cooling towers, fine mesh traveling screens, fine mesh cylindrical wedgewire screens,
and the use of groundwater for cooling tower makeup are technically feasible at AWPP from a purely
engineering design standpoint.
Based on efficiency, economics, and environmental factors, a mechanical-draft evaporative cooling tower
would be the most promising alternative for retrofitting a once-through cooling facility to closed-cycle
cooling at AWPP. The preliminary concept for a mechanical draft cooling tower retrofit at AWPP would
include the installation of two new, back-to-back cooling towers, one with 12 cells and the other with 16
cells. The proposed cooling towers would be located northwest of the power plants, on top of existing
landfills (Figure 2-1; Appendix A). Based on preliminary analysis, the use of groundwater as an alternate
water source to provide makeup water to the mechanical draft cooling towers is feasible. Site-specific
engineering considerations and factors associated with locating cooling towers at AWPP are: the
significant distance between the proposed cooling tower location and the plant; surface material from the
landfills would have to be removed and backfilled; finding a suitable location for the required quantity of
landfill material; the condensers must be upgraded; and the circulating water pipe must be replaced or
repaired with a lining/wrap system. All of these factors make the CCRS retrofit challenging and
expensive at AWPP. While the overall effectiveness in reducing entrainment is expected to be
approximately 95 percent, the overall life cycle (NPV) project costs were estimated to be $290.6 million
in 2017 dollars (Table 2-6). The social costs were estimated to range from $166.9 to $273.0 million in
2017 dollars, depending upon the discount rate used (Table 2-7).
Fine mesh modified traveling screens (0.5, 1.0, and 2.0 mm) with a fish handling and return system were
also evaluated at AWPP. Intake flow velocity, head loss, and biological effectiveness were primary
factors discussed that influence the feasibility or the ease/difficulty of implementing and operating fine
mesh modified traveling screens. While head loss does not appear to be problematic, the fine mesh
screens would increase the through-screen velocity as compared to the existing screens and is higher than
the 0.5 fps criterion, ranging from 1.1 fps for 2-mm screens to 1.7 fps for 0.5-mm screens at 25 percent
clogging. The most concerning factor using fine mesh traveling screens is that the biological effectiveness
of safely returning the now impinged eggs and larvae is uncertain. The mesh size that would be most
effective in physically excluding the species most susceptible to entrainment at AWPP (freshwater drum
and gizzard shad) would be 0.5-mm mesh, followed by 1.0 and 2.0-mm mesh. However, several studies
Technical Feasibility and Cost Study Final Summary
Alcoa Warrick Power Plant 6-2 Burns & McDonnell
evaluating the use of fine mesh demonstrate considerable variability in survival, depending upon species,
especially with the earliest life stages, and relatively poor survival for early life stages because they are
extremely fragile and, therefore, more sensitive to impingement stresses. An evaluation of fine mesh
traveling screens was completed by EPRI showed the 48-hour post-collection survival of the larvae
converted to impingement off the 0.5 and 1.0-mm fine mesh screens was extremely poor (generally less
than 30 percent regardless of screen type and the 48-hour post-collection survival of the larvae converted
to impingement off the 2.0-mm ranged from 0 to approximately 60 percent when larval length was less
than 12.0 mm and exceeded 90 percent when size exceeded approximately 12.0 mm. Based on a site-
specific evaluation, the overall effectiveness (reduction in EM) of the 0.5, 1.0, and 2.0-mm fine mesh
traveling screens at AWPP is estimated to be 50, 25, and 20 percent, respectively. The actual mesh size
used would need to be evaluated further if this technology is selected. The overall life cycle (NPV)
project costs were estimated to be $10.4 million in 2017 dollars (Table 3-4). The social costs were
estimated to range from $6.2 to $9.7 million in 2017 dollars, depending upon the discount rate used
(Table 3-5).
Fine mesh cylindrical wedgewire screens with a slot width of 0.5, 1.0, and 2.0 mm were evaluated at
AWPP. Based on the intake rate and available water depth at AWPP, the use of 96-inch diameter screens
is recommended. The number of screens required to have a maximum through-screen velocity of 0.5 fps
was nine for 2.0-mm slot width, 13 for 1.0-mm slot width, and 20 for 0.5-mm slot width. Site-specific
engineering considerations and factors associated with cylindrical wedgewire screens at AWPP are:
navigational hazards to commercial and recreational boating, screen damage from commercial vessels and
debris would require screen replacement at unknown intervals, significant permitting difficulties would
need to be overcome, and debris loading and biofouling would clog screens and increase slot velocity, and
IM. It is likely that only the 2.0-mm slot width would potentially be feasible because the other mesh sizes
would require too large of a footprint in the Ohio River, encroach on the navigation channel and interfere
with commercial boating, and would likely not be permitted by the USACE. If 2.0-mm wedgewire
screens are selected for further consideration at AWPP, APGI will need to contact the USACE and U.S.
Coast Guard to discuss the feasibility of permitting this installation. In addition to the engineering
constraints, the biological effectiveness of 2.0-mm mesh at a design through-screen velocity of 0.5 fps at
AWPP is uncertain. Based on morphometric data collected as part of the 2-year Entrainment
Characterization Study (not accounting for hydraulic mechanisms of cylindrical wedgewire screens), the
2-mm mesh would not physically exclude freshwater drum eggs and freshwater drum larvae less than 17
mm in length (Figure 3-3), and carpsucker/buffalo and herring larvae less than 12-mm in length (Figure
3-5; Figure 3-5). However, data on 2-0-mm fine mesh cylindrical wedgewire screens indicate egg
Technical Feasibility and Cost Study Final Summary
Alcoa Warrick Power Plant 6-3 Burns & McDonnell
entrainment reductions from 67 to 92 percent and larval entrainment reductions from 62 to 84 percent (see
Table 4-2). Given the size of the fish eggs and larvae at AWPP, entrainment reductions using 2.0-mm fine
mesh screens is anticipated to be on the lower side of these ranges (67 percent for eggs and 64 percent for
larvae). Using these reductions, the overall entrainment reduction at AWPP using 2.0-mm fine mesh
cylindrical wedgewire screens is 65 percent. The overall life cycle (NPV) project costs were estimated to
range from $15.9 to $32.6 million in 2017 dollars (Table 4-8). The social costs were estimated to range
from $8.7 to $27.4 million in 2017 dollars, depending upon wedgewire slot size and the discount rate
used (Table 4-9).
Water resource and alternate sources for cooling water, including groundwater wells, and wastewater
were evaluated at AWPP. Groundwater was identified as a potential alternate water source for makeup
water to the cooling tower. Groundwater and WWTPs were not feasible for technologies that will
continue to use a once-through cooling water system, such as fine mesh traveling screens and cylindrical
wedgewire screens. Based on the available aquifer thickness at the site and transmissive aquifer material
indicated by the well logs, a total of 150 vertical wells (producing 3,000 gpm each), or 39 HCWs
(producing 15 MGD each) could yield the required design intake flow requirements of 576 MGD and
require approximately 9.5 miles of riverbank for the HCWs and 14.5 miles of riverbank for the vertical
wells. Given the number of wells required, negative impacts on surrounding wells and in the aquifer, need
for property acquisition or easements, and the number of environmental clearances and road/utility
permits and agreements that would need to be obtained, the use of wells as an alternate water source for
the screening systems that would continue to use once-through cooling would be excessively expensive to
implement, and is considered infeasible. Based on the analysis of available water sources, WWTPs near
AWPP do not provide sufficient quantity for once-through cooling. The amount of flow reduction using
the closest WWTP (Newburgh WWTP (4.6 MGD)) would be 0.8 percent. This very low percentage does
not warrant the use of this water source. Given these factors, compliance and social costs were not
prepared for water reuse and alternate sources for cooling water.
Technical Feasibility and Cost Study Final Literature Cited
Alcoa Warrick Power Plant 7-1 Burns & McDonnell
7.0 LITERATURE CITED
Beak Consultants, Inc. (2000a). Post-Impingement Fish Survival Dunkirk Steam Station, Winter, Spring, Summer, and Fall 1998–1999. Prepared for NRG Dunkirk Power LLC.
Beak Consultants, Inc. (2000b). Post-Impingement Fish Survival at Huntley Steam Station, Winter and Fall 1999. Final Report. Prepared for Niagara Mohawk Power Corporation.
Browne, M.E., L.B. Glover, D.W. Moore, and D.W. Ballengee. (1981, April 22-24). In-Situ Biological and Engineering Evaluation of Fine Mesh Profile-Wire Cylinders at Powerplant Intake Screens. In P.B. Dorn and Johnson (Eds.), Advanced Intake Technology for Power Plant Cooling Water Systems (pg. 36-46). Proceedings of the Workshop of Advanced Intake Technology held at the Sheraton-Harbor Island Hotel San Diego, California, April 22-24.
Brueggemeyer, V. D., D. Cowdrick, and K. Durell. (1988). Full-Scale Operational Demonstration of Fine-Mesh Screens at Power Plant Intakes. In Fish Protection at Steam and Hydroelectric Power Plants, San Francisco, California, October 28–31, 1987. Sponsored by Electric Power Research Institute (EPRI). CS/EA/AP-5663-SR.
Carolina Power & Light Company. (1985a). Brunswick Steam Electric Plant 1984 Biological Monitoring Report. Biology Unit Environmental Services Section.
Carolina Power & Light Company. (1985b). Brunswick Steam Electric Plant Cape Fear Studies Interpretive Report. Biology Unit Environmental Services Section.
Electric Power Research Institute (EPRI). (2005). Field Evaluation of Wedge Wire Screens for Protecting Early Life Stages of Fish at Cooling Water Intakes. Technical Report 1010112. Palo Alto, California: EPRI.
Electric Power Research Institute (EPRI). (2006a). Laboratory Evaluation of Modified Ristroph Traveling Screens for Protecting Fish at Cooling Water Intakes. Technical Report 1013238. Palo Alto, CA: EPRI.
Electric Power Research Institute (EPRI). (2006b). Field Evaluation of Wedge Wire Screens for Protecting Early Life Stages of Fish at Cooling Water Intake Structures, Chesapeake Bay Studies. EPRI Report Summary for EPRI Report 1012542. Section 316(a) and 316(b) Fish Protection Issues Program. Palo Alto, CA: EPRI.
Electric Power Research Institute (EPRI). (2009). Laboratory Evaluation of Fine-mesh Traveling Water Screens for Protecting Early Life Stages of Fish at Cooling Water Intakes: Research Progress Update Through 2008. Technical Report 1015578. Palo Alto, CA: EPRI.
Electric Power Research Institute (EPRI). (2010). Laboratory Evaluation of Fine-mesh Traveling Water Screens. Technical Report 1019027. Palo Alto, CA: EPRI.
Electric Power Research Institute (EPRI). (2011a). Net Environmental and Social Effects of Retrofitting Power Plants with Once-through Cooling to Closed-cycle Cooling. Technical Report 1022760. Palo Alto, CA: EPRI.
Electric Power Research Institute (EPRI). (2011b). Closed-Cycle Cooling System Retrofit Study. Capital and Performance Cost Estimates. Technical Report 1022491. Palo Alto, CA: EPRI.
Technical Feasibility and Cost Study Final Literature Cited
Alcoa Warrick Power Plant 7-2 Burns & McDonnell
Electric Power Research Institute (EPRI). (2012). Fish Protection at Cooling Water Intake Structures: A Technical Reference Manual – 2012 Update. Technical Report 3002000231. Palo Alto, CA: EPRI.
Electric Power Research Institute (EPRI). (2015). Design of Fish Return Systems and Operations/Maintenance Guidelines. Technical Report 3002001422. Palo Alto, CA: EPRI.
Hanson, B. N. (1981). Studies of Larval Striped Bass (Morone saxatilis) and Yellow Perch (Perca flavescens) Exposed to a 1 mm Slot Profile-Wire Screen Model Intake. In P. B. Dorn and J. T. Larson (Eds.), Proceedings of the Workshop on Advanced Intake Technology. San Diego, California.
Hanson, B.N., W.H. Bason, B.E. Beiz, and K.E. Charles. (1977). A Practical Intake Screen which Substantially Reduces Entrainment. Fourth Nation Workshop on Entrainment and Impingement. Chicago, Illinois. Sponsored by Ecological Analysts, Inc.
Henderson, P.A., R. M. H. Seaby, and J. R. Somes. (2003). A Comparison of Ecological Impacts of Power Plant Once-Through, Evaporative and Dry Cooling Systems on Fish Impingement and Entrainment. Pisces Conservation Ltd.
Kuhl, G. H. and K. N. Mueller. (1988). Prairie Island Nuclear Generating Plant Environmental Monitoring Program 1988 Annual Report Fine Mesh Vertical Traveling Screens Impingement Survival Study. Northern States Power Company.
Lifton, W.S. (1979). Biological Aspects of Screen Testing on the St. Johns River, Palatka, Florida. In Passive Screen Intake Workshop. St. Paul, MN: Johnson Division UOP Inc.
McLaren, J. B. and L. R. Tuttle Jr. (2000). Fish Survival on Fine Mesh Traveling Screens. Environmental Science and Policy 3: S369-S374.
Otto, R.G., T.I. Hiebert, and V.R. Kranz. (1981). The Effectiveness of a Remote Profile-Wire Screen Intake Module in Reducing the Entrainment of Fish Eggs and Larvae. In P. B. Dorn and J. T. Larson (Eds.), Proceedings of the Workshop on Advanced Intake Technology. San Diego, California.
SPX Cooling Technologies, Inc. (2009). Cooling Tower Fundamentals. Second Edition. Overland Park, Kansas, USA.
Taft, E. P., T. J. Horst, and J. K. Downing. (1981). Biological Evaluation of a Fine-Mesh Traveling Screen for Protecting Organisms. In Workshop on Advanced Intake Technology, San Diego, California, April 22–24.
Tenera Environmental. (2013). Length-Specific Probabilities of Screen Entrainment of Larval Fishes Based on Head Capsule Measurements. In Support of the California State Water Resources Control Board Once-Through Cooling Policy Nuclear-Fueled Power Plant (NFPP) Special Studies.
Thompson, T. (2000). Intake Modifications to Reduce Entrainment and Impingement at Carolina Power and Light Company’s Brunswick Steam Electric Plant, Southport, North Carolina. Environmental Science and Policy, 3, S417-S424.
Technical Feasibility and Cost Study Final Literature Cited
Alcoa Warrick Power Plant 7-3 Burns & McDonnell
U.S. Environmental Protection Agency (EPA). (2004). Technical Development Document for the Final Section 316(b) Phase II Existing Facilities Rule. Office of Water. EPA 821-R-04-007.
U.S. Environmental Protection Agency (EPA). (2014a). National Pollutant Discharge Elimination System—Final Regulations to Establish Requirements for Cooling Water Intake Structures at Existing Facilities and Amend Requirements at Phase I Facilities; Final Rule. 40 CFR Parts 122 and 125. August 15, 2014. EPA–HQ–OW–2008–0667, FRL–9817–3.
U.S. Environmental Protection Agency (EPA). (2014b). Technical Development Document for the Final Section 316(b) Existing Facilities Rule. Office of Water. EPA-821-R-14-002. May.
Weisberg, S.B., W.H. Burton, F. Jacobs, and E.A. Ross. (1987). Reductions in Ichthyoplankton Entrainment with Fine Mesh, Wedge Wire Screens. North American Journal of Fisheries Management, 7, 386-393.
Zeitoun, I.H., J.A. Gulvas, J.Z. Reynolds. (1981). Effectiveness of Small Mesh Cylindrical Wedge Wire Screens in Reducing Fish Larvae Entrainment at an Offshore and an Onshore Location of Lake Michigan. In: P.B. Dorn and Johnson (eds.), Advanced Intake Technology for Power Plant Cooling Water Systems (pg. 57-64). Proceedings of the Workshop of Advanced Intake Technology held at the Sheraton-Harbor Island Hotel San Diego, California. April 22-24.
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- SOCIAL COST STUDY
Social Costs of Purchasing and Installing Entrainment Reduction Technologies: Alcoa Warrick Power Plant Prepared for: Alcoa Corporation Prepared by: Veritas Economics January 2018
Office: 919.677.8787 Economic Consulting Fax: 919.677.8331 VeritasEconomics.com
Veritas1851 Evans RoadCary, NC 27513
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Table of Contents
Section Page
1. The Social Costs of Purchasing and Installing Technologies ........................... 1
1.2 Financial and Regulatory Environment......................... Error! Bookmark not defined. 1.3 Market Environment .................................................................................................... 8 1.4 Social Costs of Compliance ........................................................................................ 8
2. References ........................................................................................................... 12
Appendix A Power System and Off-Site Emissions Study for Alcoa Warrick Power Plant ...................................................................................................................... 14
Power System Overview .................................................... Error! Bookmark not defined.
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1. The Social Costs of Purchasing and Installing Technologies Reducing entrainment can generally be accomplished by altering operations; closing the
facility; or by purchasing, installing, and operating entrainment reduction technologies. These
activities lead to a number of physical changes and financial effects that can produce social costs.
The Environmental Protection Agency (EPA) defines social costs as the “opportunity cost to
society of employing scarce resources to prevent the environmental damage otherwise occurring
except for the design and operation of compliance technology” (79 Fed. Reg. 158, 48387). These
are further delineated as each of the following:
• Real-Resource Compliance Costs—direct purchase, installation, and operation
• Government Regulatory Costs—monitoring, administration, and enforcement
• Environmental Externalities—increased fuel cost impacts from energy penalty and proposed outages and property value, recreation, human health, and increased water consumption impacts.
This report covers each of these social cost categories. Real-Resource Compliance Costs result
from purchasing and installing technologies at the Alcoa Warrick Power Plant (AWPP).
Government Regulatory Costs are developed from EPA’s estimates in the national rule (79 Fed.
Reg. 158, 48300–48439). The social costs of environmental externalities are developed from the
Power System Capacity Loss and Offsite Emissions Study. Appendix A presents the methods
and results of this evaluation.
Figure 1 depicts how expenditures on entrainment reduction technologies would have
implications for Alcoa Corporation’s (Alcoa) balance sheet and construction activities. As the
figure depicts, construction generates nearby economic activity, which can lead to good social
outcomes such as more jobs. These economic impacts can be studied via economic input-output
analysis techniques. As related local outcomes are typically considered good, they are not
measured under social costs and not considered further here.
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Figure 1: Social Costs Associated with Technology Expenditures
Balance sheet implications are transmitted through financial, electricity, and regulatory
markets to register as social costs to shareholders, ratepayers, and the general population. How
these are realized as social costs depends upon the regulatory and market environments.
1.1 Entrainment Reduction Technology Options The Alcoa Warrick Power Plant (AWPP) is a coal-fueled, steam-electric generating station
located on the Ohio River in Newburgh, Indiana approximately 13 miles southeast of Evansville,
Indiana. Operational since the early 1960’s, Units 1, 2, 3, and 4 collectively produce 750MW of
electricity primarily for the Alcoa Warrick Operations manufacturing facility. The generating
station also provides potable water, steam, and high temperature water for the manufacturing
facility. Unit 4 is co-owned by Vectren Energy Delivery of Indiana – South (Vectren South), an
electric and natural gas utility subsidiary of Vectren Corporation (Vectren). Vectren South
operates in Indiana and west central Ohio.
The current, once-through cooling water system at AWPP has a total daily intake flow
(DIF) of 576 million gallons per day (MGD) with an actual intake flow (AIF) of 518 MGD and 91%
of the withdrawn water is used for cooling purposes. Burns & McDonnell have considered several
alternative screen, water reuse, and closed-cycle cooling technologies (Burns and McDonnell
2017) and have evaluated the following options for AWPP:
Veritas-0117
Technology Expenditures
Balance Sheet Implications
Construction Activities
Nearby Jobs, Taxes
Shareholders
RatepayersElectricity Market
Physical Change System Effects Social Cost Categories (r)(10)
Economic Impacts (Jobs, Taxes)
(r)(10)(iii)Compliance Cost
(r)(10)(iii)
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• Closed-cycle cooling tower
• Fine mesh traveling screens (FMS) with 0.5mm, 1.0mm, and 2.0mm mesh size
• Cylindrical wedge wire screens with 0.5mm, 1.0mm, and 2.0mm mesh sizes
Table 1 summarizes the estimated capital costs for each technology.
Table 1 Capital Cost Estimates for Feasible Alternatives at AWPP
Technology Capital Cost
Estimate Closed-cycle cooling $246.6M
Fine mesh traveling screens – 2.0, 1.0, and 0.5mm mesh sizea $9.0M
Wedge wire screens 0.5mm mesh size $35.8M Wedge wire screens 1.0mm mesh size $23.7M
Wedge wire screens 2.0mm mesh size $16.5M a The capital and operation and maintenance costs are the same for 2.0, 1.0, and 0.5mm fine mesh
traveling screens.
Balance sheet implications would accompany the purchase, installation and operation of
any of these entrainment reduction technologies. Costs vary from lower cost fine mesh traveling
screen technology options to higher cost closed-cycle cooling retrofit options. Detailed costs of
the feasible options are presented in Section 1.4 of this report.
1.2 Financial and Regulatory Environment AWPP is operated by Alcoa Power Generating Incorporated (APGI), a division of Alcoa.
Headquartered in Pittsburgh, Pennsylvania. Alcoa is a global aluminum company comprised of
bauxite mining, alumina refining, aluminum production (smelting, casting and rolling), and energy
generation (Alcoa 2017a). With 14,000 employees in ten countries, Alcoa is the world’s 6th largest
aluminum producer and the world’s largest bauxite miner and refiner of alumina (Alcoa 2016b).
Products include primary aluminum, sheet aluminum, and rolled aluminum. In addition, electricity
is generated for use during the manufacturing process with excess capacity sold into the
competitive open market. The production of aluminum is an energy intensive process requiring
between 13MW and 17MW of electricity for one metric ton (MT) of aluminum output. Alcoa’s eight
worldwide energy facilities have a combined capacity of 1,685MW. This meets the electricity
needs of approximately 14% of smelter operations with the remainder being supplied through
long-term power contracts (Alcoa 2016b).
AWPP uses cooling water for both industrial processes and on-site power generation
through the operation of 4 coal-fired generators with a combined generating capacity of 750MW.
Units 1-3 and half of Unit 4 (600MW in total) produce electricity for the adjacent Alcoa Warrick
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Operations manufacturing facility. The facility currently operates a casthouse and rolling mill to
produce aluminum sheet that is used primarily in the aluminum can packaging end use market.
In March 2016, the facilities’ smelter operation was closed which resulted in approximately 36%
of Alcoa’s portion of AWPP’s electric generating capacity being sold into the open market (Alcoa
2016b). The Company plans to restart 3 of the 5 smelter pot lines in the first quarter of 2018 to
supply the rolling mill with molten metal to meet expected increases in demand for aluminum
sheet. With the smelter restarting, the amount of excess electricity sold into the open market will
be reduced.
AWPP also produces electricity to serve the needs of Vectren South’s 144,000 electric
customers in seven southwest Indiana counties. Fifty percent of the 300MW generated by AWPP
Unit 4 (150MW in total) is provided to Vectren South for use by their electric customers. With a
system generating capacity of nearly 1,300MW, the AWPP plant provides approximately 12% of
Vectren South’s total generation portfolio (Vectren 2017). Figure 2 presents the Vectren South
electric service territory and location of the AWPP and Alcoa Warrick Operations manufacturing
facility.
With respect to social costs, the cost of purchasing, installing, and operating entrainment-
reduction technologies are Real-Resource Compliance Costs. As a co-owner of Unit 4, Vectren
South will be responsible for a portion of these costs. Vectren is potentially eligible to recover all
or part of their share of the costs of installing entrainment reduction technologies at AWPP. A
traditional, rate-based electric utility generating plant is built by a regulated utility specifically to
serve that utility’s customers. Through the ratemaking process, customers are required to pay
for the plant’s construction, operation, and maintenance costs. Investors in the utility are then
allowed a fair financial return on the capital investment. Electric utilities operating in Indiana can
file a rate request with the Indiana Utility Regulatory Commission (IURC) for recovery of costs
and establishment of a fair rate of return. The IURC holds hearings and based on the facts can
approve a settlement agreement authorizing cost recovery (IURC 2017). Procedures involved in
rate request hearings include allowing intervener comments and Vectren South rebuttals. This
process, along with the permitting itself, results in costs to the government, which are Government
Regulatory Costs.
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Figure 2: Vectren South Service Territory and Generation Assets
Blackfoot Clean Energy Facility
WarrickF.B. Culley
A.B. Brown
Kentucky
Alcoa Warrick Operations
Legend Vectren South Service Territory and
Generation Assets
Vectren South Service TerritoryFuel Source
A.B. Brown Coal & Natural GasF.B. Culley CoalWarrick* CoalBlackfoot Clean Energy Facility Renewable EnergyBenton County Wind Farms Renewable Energy* Vectren owns 50% of Warrick Unit 4
Illinois Indiana
Benton County Wind Farms
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Since installing entrainment-reducing technologies is a regulatory environmental
compliance requirement (as opposed to typical operations and maintenance), these costs are
typically included in a future rate case filing and passed on to customers in the form of higher
electric rates. However, Vectren has stated their intent to exit joint operations with Alcoa at AWPP
Unit 4 in mid-2020. Vectren’s 2016 Integrated Resource Plan (Vectren 2016) outlines a twenty-
year plan to transition to an energy portfolio that includes increases in natural gas and solar
generation and decreases in coal generation. Given Vectren’s plan to discontinue co-ownership
of AWPP Unit 4 during the compliance timeframe, it is unlikely that any costs of compliance at
AWPP will be passed onto Vectren South’s electric customers. For purposes of this analysis, it
is therefore assumed that 100% of the compliance costs at AWPP will be the responsibility of
Alcoa.
With respect to social costs then, the Real-Resource Compliance Costs would have to be
passed onto Alcoa’s shareholders as an additional cost of operating AWPP. These costs could
result in lower returns for investors depending on future market conditions. Lower returns could
make Alcoa’s stock less attractive for investors which could put downward pressure on the stock
price negatively impacting Alcoa’s ability to raise capital for operations. Alcoa’s recent financial
performance is instructive with respect to the implications of increased costs on the balance sheet.
The ability to absorb these costs without significant negative financial impacts is dependent in
large part on the financial health of the overall company.
As the inventor of the creation of aluminum through electrolysis, Alcoa is a global leader
in the production of bauxite, alumina, and aluminum. The aluminum industry is a highly
competitive global industry with price and production costs critical to the success and profitability
of producers. The London Metal Exchange (LME) primary aluminum price reflects the market
price for one ton of aluminum. For every $100 per ton decline in LME aluminum price, Alcoa net
earnings decline approximately $190 million (Yahoo Finance 2015). Supply and demand is the
main driver for LME aluminum prices. Producers like Alcoa adjust manufacturing capacity
(supply) to meet market demand at the prevailing LME market price. Demand for aluminum is
highly correlated to global economic growth as demand is greatest in highly cyclical end-use
markets such as the commercial construction, transportation, automotive, and aerospace
industries. The slowdown of global economies coupled with a global oversupply resulted in weak
alumina and aluminum prices which caused parent company Alcoa Incorporated to post losses
from 2014 to 2016 (Alcoa 2016a). Significant write-downs of almost $3 billion have been taken
to idle, close, or sell manufacturing plants to reduce operating costs and excess capacity (Alcoa
2016b). In the fourth quarter of 2016, due to persistent market pressures, Alcoa Incorporated
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split into two companies: Alcoa and Arconic to streamline the organization and shore up the
balance sheet of the core aluminum business (mining/refining/smelting) retained under the Alcoa
nameplate.
Efforts to strengthen their operations and balance sheet are starting to pay off. Alcoa has
rightsized their commodity aluminum business and reduced their position on the aluminum
manufacturing cost curve from the 51st to the 38th percentile (Alcoa 2016a). At the same time,
LME aluminum prices have rebounded. After declining 43% from 2011 to 2016, prices are up
25% this year (LME 2017, Macrotrends 2017). The outlook for global demand is improving as
well. China has implemented stricter environmental policies and closed heavy polluting smelters
representing approximately 10% of their aluminum capacity which equates to 6% of global supply.
At the same time, China’s economic stimulus plan will result in additional infrastructure projects
and increased demand for aluminum. With China consuming more aluminum while producing
less, Alcoa is well positioned to meet both the increased demand by China and the global demand
they previously supplied. Alcoa increased its aluminum demand forecast by 0.25% to reflect an
improved market outlook (Alcoa 2017c, Motley Fool 2017b).
Market improvements have translated to stronger financials as Alcoa’s balance sheet has
experienced increased revenues and earnings over the first three quarters of 2017. The stock
price is up 15% through November, slightly below the S&P 500 Index performance (Morningstar
2017). In June, Alcoa’s credit rating was upgraded from “stable” to “positive” while maintaining a
BB- non-investment grade rating (S&P Global Platts 2017). While not yet large enough to pay a
dividend, cash flows have improved. After averaging $13 million in cash flow per year from 2013-
2016, Alcoa ended third quarter 2017 with $1.1 billion in cash on hand (Alcoa 2017c, Motley Fool
2017a). While still subject to volatile market forces, Alcoa expects continued financial
performance improvements in the coming years.
In addition to 316(b) compliance costs, Alcoa needs to invest in AWPP to be compliant
with EPA’s 2015 rules for effluent limitations guidelines (ELG) for water discharges and coal
combustion residuals (CCR) for operation of coal ash ponds. AWPP’s ELG and CCR non-
compliance was another factor in Vectren’s decision to terminate co-ownership of Unit 4 as
opposed to sharing in these forthcoming compliance costs (Vectren 2016). These costs will make
AWPP more expensive to run and with Vectren no longer sharing in a portion of the post-2020
operational costs, the overall operations at AWPP will become costlier over the long term.
Installing entrainment reducing technologies at AWPP to comply with EPA’s 316(b) Final
Rule represents an additional financial and operational challenge to Alcoa. The economics of
operating the plant will likely be re-evaluated with this regulatory requirement. Compliance costs
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would have to be paid out of Alcoa’s cash balance which is in the process of being built back up
after years of market pressures and financial struggles. This could put downward pressure on
the stock price which could negatively impact Alcoa’s ability to raise additional investment monies
for operations.
1.3 Market Environment AWPP currently supplies critically needed electricity to the Alcoa Warrick Operations
casthouse and rolling mill. The significance of the generating plant on Alcoa’s operations will be
even higher with the Q1 2018 planned restart of smelter operations. Any construction downtime
that takes the plant offline will effectively halt production at the smelters, casthouse, and rolling
mill and will significantly impact Alcoa’s operating profits. The ability to secure replacement power
in the open market will be critical in maintaining manufacturing operations at the facility.
AWPP is geographically located within Zone 6 of the Midcontinent Independent System
Operator (MISO) regional transmission organization. Headquartered in Carmel, Indiana, MISO
provides electric reliability and coordination services in nine geographically defined local resource
zones across fifteen states and Manitoba, Canada. Excess generation at AWPP is bid into the
MISO power market and dispatched at least cost to participating members. To maintain regional
reliability, MISO establishes planning reserve margins by zone where member utilities are
required to meet a minimum capacity reserve margin. Electric utilities are required to maintain
adequate reserve margins which would enable them to meet high demand during peak periods,
extreme weather events, planned plant outages for maintenance, inspections, refueling, and for
any unplanned outage that may occur. Given the existence of zone specific reserve margins,
Alcoa could potentially buy capacity from MISO during construction downtime for installation of
entrainment reducing technologies. However, according to the 2016 Resource Adequacy Survey
results, Zone 6 is projected to have an 800MW shortfall by 2018 at the earliest (Vectren 2016).
Consequently, the availability of replacement capacity from the MISO market is uncertain. If
capacity is available, higher cost generating units would need to be dispatched to replace the
power previously produced by AWPP. The Power System Capacity Loss and Offsite Emissions
study presented in Appendix A discusses this scenario and associated impacts in more detail.
1.4 Social Costs of Compliance The first step in estimating the social costs of compliance is to determine whether the
entrainment reducing technology costs result in the plant becoming uneconomic to operate. A
premature shutdown of the plant would have social costs related to job loss, loss of income and
expenditures, tax base loss, increased electricity costs due to generation being dispatched at a
higher price from less efficient plants, and increased infrastructure costs to maintain grid reliability.
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Alcoa’s tenuous financial standing and volatile market environment coupled with the plants’
increased costs of operation with the ELG and CCR compliance costs and expected loss of
Vectren as a contributor to the costs of operating Unit 4 present a potentially difficult future for
AWPP’s long-term viability. However, as the only electric supplier powering Alcoa Warrick’s
operations of the casthouse, rolling mill, and smelters that are set to be restarted next year, AWPP
is invaluable suggesting that only an extraordinarily expensive conversion requirement would lead
to premature closure. Therefore, this analysis specifies Alcoa will incur the entrainment reducing
compliance costs and continue to operate the Warrick plant. Table 2 summarizes the results of
this evaluation and its implication for social costs.
Following the requirements of the rule, Table 2 evaluates social costs under two discount
rates: 3 and 7 percent (79 Fed. Reg. 158, p. 48428). As the first column of Table 2 shows, the
top half of the table presents the present value of social costs discounted at 3 percent, and the
bottom half presents the social costs discounted at 7 percent. The next column of the table
presents each of the feasible technologies evaluated at AWPP. The third and fourth columns
present the engineering costs estimated for each feasible technology. The third column presents
the estimated design, construction, and installation costs, and the fourth column presents the
annual operation and maintenance (O&M) costs for each feasible technology.
The remaining columns in the table present the individual categories of social costs
developed for this analysis: balance sheet cash reserve decrease, fuel costs, externality costs,
and permitting costs. The analysis discounts the future stream of each of these social costs at
the relevant discount rate and sums them over the years they are specified to occur to develop
the Total Present Value Social Cost estimate presented in the penultimate column. The table
concludes by presenting the Annual Social Cost estimate for each technology. The annual
estimate divides the Total Social Cost by the number of years the analysis is conducted over.
Engineering costs are specified as occurring over a twenty-year time period. Fuel costs
are specified to occur during construction, based on outage impacts, and during operation, based
on efficiency and auxiliary load impacts. Regulatory documents will be submitted in 2018 and the
timing for activities related to installation are dependent on the technology being installed. Table
3 reflects the timing specifications for each of the three alternatives.
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Table 2 Total Engineering & Social Costs of Feasible Technology Options at AWPP
Engineeringa Social Costs
Discount Rate Technology Type
Total Design, Construction, &
Installation Costs Annual
O&M Costs
Balance Sheet Cash Reserve
Decrease Fuel
Costsa Externality
Costsb Permitting
Costsa
Total Present Value of
Social Costs
Annual Social Costs
3% Closed-cycle cooling $246.6M $6.0M $242.2M $46.6M - $75k $273.0M $13.7M
Fine mesh traveling screens 2mm, 1mm, & 0.5mmc $9.0M $250k $9.7M $191k - $15k $9.7M $484.4k
Wedge wire screens 0.5mm $35.8M $210k $27.8M $191k - $35k $27.4M $1.4M
Wedge wire screens 1mm $23.7M $190k $19.1M $191k - $35k $18.9M $945k
Wedge wire screens 2mm $16.5M $170k $13.8M $191k - $35k $13.7M $685k
7% Closed-cycle cooling $246.6M $6.0M $148.1M $46.6M - $75k $166.9M $8.3M
Fine mesh traveling screens 2mm, 1mm, & 0.5mmc $9.0M $250k $6.1M $191k - $15k $6.2M $308k
Wedge wire screens 0.5mm $35.8M $210k $17.6M $191k - $35k $17.4M $871k
Wedge wire screens 1mm $23.7M $190k $12.1M $191k - $35k $8.9M $444k
Wedge wire screens 2mm $16.5M $170k $8.7M $191k - $35k $8.7M $435k
a The engineering, fuel, and permitting costs are undiscounted and in 2017 dollars. The social costs associated with each technology are discounted at 3 and 7 percent using the specifications outlined in Table 3.
b Externality costs include decreases in social wellbeing resulting from property value, recreation, human health, reliability, and water consumption impacts. These categories of social costs were beyond the scope of this analysis and are not quantified in this evaluation.
c The capital and operation and maintenance costs are the same for 2, 1, and 0.5mm fine mesh traveling screens, so we present them together on one row.
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Table 3 Timing Specified for Feasible Technologies at AWPP
Entrainment Reducing Technology
Regulatory Documents Submitted
Permitting, Design,
Construction & Installation
O&M Costs Begin
Years of Operation
Closed-cycle cooling 2018 2018-2021 2022 20 Fine mesh traveling screens 0.5mm, 1.0mm, or 2.0mm
2018 2018-2020 2021 20
Wedge Wire Screens 0.5mm, 1.0mm, or 2.0mm
2018 2018-2020 2021 20
The social costs of each technology include the expected balance sheet cash reserve
decrease associated with each technology, the additional, system-level fuel costs that would be
incurred with each technology, and the permitting costs. As previously noted, the analysis
specifies that all the engineering costs are paid for with Alcoa’s cash reserves. To develop the
cash reserve decrease, the design, construction, and installation costs are allocated over the
specified construction and installation time period presented in Table 3. Operation and
maintenance costs are then added for each year the technology is operational, and the future
stream of those costs are discounted by 3 and 7 percent to develop the present value estimate
for each discount rate.
Fuel costs represent the additional power needed to operate the new technologies and
the additional fuel needed from running less efficient units during installation construction outages.
The fuel costs are developed from evaluating backpressure and auxiliary load effects, capacity
losses from each of the technologies with estimated outage times, and electricity consumption
associated with each technology. Details of the fuel cost estimates are presented in Appendix A.
Permitting costs include the total costs associated with permitting, monitoring,
administering, and enforcing the technology selection and installation. Costs are incurred by the
government as the permitting and review process is undertaken. These vary with the type of
technology, as certain technologies require substantially more permitting. Those with more
significant environmental effects would have higher permitting costs. These costs are initially
borne by the government, but ultimately paid by taxpayers. Permitting costs are developed from
EPA’s estimates in the national rule (79 Fed. Reg. 158, 48300-48439) and are specified to be 2%
of direct capital costs.
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2. References Burns and McDonnell. 2017. Cost Estimates for Alcoa Warrick Power Plant.
Alcoa. 2016a. “Annual Report for 2016”. March 17, 2017. Available at http://investors.alcoa.com/financial-reports/annual-reports-and-proxy-information. Retrieved on October 31, 2017.
Alcoa. 2016b. “Form 10-K Report for the Fiscal Year Ended December 31, 2016. Available at https://www.sec.gov/Archives/edgar/data/4281/000119312517062657/d293282d10k.htm. Retrieved on October 31, 2017.
Alcoa. 2017a. “Company Website. Available at https://www.alcoa.com/global/en/home.asp. Retrieved on October 31, 2017.
Alcoa. 2017b. “Alcoa Corporation Plans Partial Restart of Aluminum Smelter at Warrick Operations”. July 11, 2017. Available at http://investors.alcoa.com/news-releases/2017/07-11-2017-210502599. Retrieved on November 14, 207.
Alcoa. 2017c. “Alcoa Corporation Reports Third Quarter 2017 Results”. October 18, 2017. Available at http://investors.alcoa.com/news-releases/2017/10-18-2017-210950457. Retrieved on November 14, 2017.
IURC. 2017. “About the IURC”. Available at http://www.in.gov/iurc/2451.htm. Retrieved on November 16, 2017.
LME. 2017. “LME Aluminum”. Available at https://www.lme.com/Metals/Non-ferrous/Aluminium#tabIndex=0. Retrieved on November 9, 2017.
Macrotrends. 2017. “Aluminum Prices Interactive Historical Chart”. Available at http://www.macrotrends.net/2539/aluminum-prices-historical-chart-data. Retrieved on November 14, 2017.
Morningstar. 2017. “Alcoa Corp. AA”. Available at http://www.morningstar.com/stocks/XNYS/AA/quote.html. Retrieved on November 11, 2017.
Motley Fool. 2017a. “Alcoa Stock Upgraded: What You Need to Know”. January 25, 2017. Available at https://www.fool.com/investing/2017/01/25/alcoa-stock-upgraded-3-things-you-need-to-know.aspx. Retrieved on November 14, 2017.
Motley Fool. 2017b. “Here’s Why Alcoa Gained 20.6% in August”. September 8, 2017. Available at https://www.fool.com/investing/2017/09/08/heres-why-alcoa-gained-206-in-august.aspx. Retrieved on November 14, 2017.
S&P Global Platts. 2017. “S&P Upgrades Alcoa’s Rating Outlook on Margins Boost”. June 21, 2017. Available at https://www.platts.com/latest-news/metals/sydney/sampp-upgrades-alcoas-rating-outlook-on-margins-26756742. Retrieved on November 16, 2017.
Vectren. 2016. “2016 Integrated Resource Plan”. December 2016. Available at https://www.vectren.com/assets/downloads/planning/irp/IRP-2016-vol1.pdf. Retrieved on November 16, 2017.
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Vectren. 2017. “About Vectren Corporation”. Available at https://www.vectren.com/assets/downloads/corporate/vectren-factsheet.pdf. Retrieved on November 14, 2017.
Yahoo Finance. 2015. “LME Aluminum is Trading at 17-month Low on Weak Macros”. June 19, 2015. Available at https://finance.yahoo.com/news/lme-aluminum-trading-17-month-132136854.html. Retrieved on November 9, 2017.
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Appendix A Power System and Off-Site Emissions Study for Alcoa Warrick
Power Plant
Hourly Energy Penalty, Power System Capacity Loss and Off-Site Emissions Study for Alcoa Warrick Power Plant FINAL Prepared for: Alcoa Prepared by: Veritas Economics January 2018
Office: 919.677.8787 FINAL Economic Consulting Fax: 919.677.8331 VeritasEconomics.com
Veritas1851 Evans RoadCary, NC 27513
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Table of Contents
Section Page
Power System Outage, Equipment Load, and Backpressure ................................. 19
Outages ............................................................................................................................ 19 Backpressure and Equipment Load .................................................................................. 20 Power System ................................................................................................................... 22 Power System Simulation ................................................................................................. 24
Quantitative Evaluation .............................................................................................. 26
Estimate Hourly Energy Penalty ........................................................................................ 26 Energy Penalty Study Approach ............................................................................... 27 Step 1—Source Water and Wet Bulb Data ............................................................... 31 Step 2—Calculate Cooling Tower Circulating Temperatures ..................................... 33 Step 3—Calculate Cooling Tower Circulating Temps ................................................ 33 Step 4—Estimate the Water Temperature to Heat Rate Curve ................................. 34 Step 5—Determine Efficiency/Capacity Impacts ....................................................... 35
Specify Hourly Load for Upper Midwest ............................................................................ 36 Operate Model Under Baseline Conditions ....................................................................... 36 Create Scenarios Representing Warrick Conversion and Ongoing Operations ................. 38 Run Simulations to Create Counterfactual Dispatch .......................................................... 38 Calculate Net Differences in Fuel Consumption, Costs, and Emissions ............................ 39
References ................................................................................................................... 41
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Power System Outage, Equipment Load, and Backpressure Many important physical and economic effects of reducing entrainment are transmitted
through the power system. These arise from outages for technology installation, electricity
consumption, and generation efficiency changes from cooling water temperature differentials.
This report studies these effects to develop information for (r)(10), (r)(12), and the 125.98(f) Must
and May factors.
Outages Extended outage times during technology installation are effectively temporary capacity
reductions. As depicted in Figure 1, these construction outages lead to system-level efficiency
and capacity changes. Significant capacity reductions can affect system reliability, which can
have social costs. Electrical system reliability effects are a factor that Directors may consider in
determinations (May 4—Reliability Impacts). These effects are unlikely with planned outages and
are not evaluated in this study.
Figure 1: Effects of Construction Outage Time
Outages always lead to less efficient dispatch and changes in energy consumption. These
are to be assessed under (r)(12)(i)—Energy Consumption. Changes in energy consumption will
impact electricity production costs, leading to social costs that must be quantified in (r)(10)(iii)—
Outages Other. Also, the re-dispatch associated with system-level efficiency changes leads to
stack emissions changes which are to be studied under (r)(12)(ii)—Emissions Health and
Physical Change System Effects Social Cost Categories(r)(10)
Veritas-0119
Environmental Impacts
Health Impacts
ConstructionOutage Time
(12)(i)—Energy Consumption
Shareholders
Ratepayers
Economic Impacts (Jobs, Taxes)System Efficiency
& Capacity Changes
Stack Emission Changes
Electricity Price & Output Changes
12(iii)—Emissions Health and Environment
May 4—Reliability Impacts
Must 2—Pollutant Impacts
(10)(iii)—Outages and Other
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Environment. These emissions are a factor that Directors are required to consider (Must 2—
Pollutant Impacts).
Outages for equipment installation occur when facilities are unable to access cooling
water. This is the case during certain undertakings such as expanding an existing intake or
connecting wedgewire screens or cooling towers. Much of the time required for installing cooling
towers can occur with the units on line. Connecting supply and return lines to the towers would
require that the units be off-line. The engineering evaluation indicates that five weeks of off-line
time would be required. This outage time is specified to occur from March through April to avoid
working on the tie-in through the peak of winter.
The effect of an outage for equipment installation is evaluated by modeling the outage
within the context of the relevant power and economic systems. This is accomplished by
developing a counterfactual “With Construction Outage” specification. Unit capacity is set at zero
over the specified outage period. With capacity adjusted in this manner, a power system
simulation model (Environmental Policy Simulation Model [EPSM]) is operated and differences in
operations across Baseline and With Construction Outage conditions are evaluated (Veritas
Economics 2011).
Backpressure and Equipment Load Certain other effects become important once entrainment reduction is underway. These
are most pronounced with cooling towers. As depicted in the figure below, cooling towers require
electricity to operate. This leads to net electrical generation efficiency/capacity effects and energy
consumption that must be identified under (r)(12), (12)(i)—Energy Consumption. As with outages,
these energy consumption changes have social costs and lead to stack emission changes. The
Rule requires assessing related effects under (r)(12), (12)(i)—Energy Consumption, (12)(ii)—
Emissions Health and Environment, and these are a factor Directors must consider (Must 2—
Pollutant Impacts). Moreover, there is significant discussion in the preamble of the Final Rule
indicating the importance of related effects.1,2
1 “… the social cost of the energy penalty is the cost of generating the electricity that would otherwise be available for
consumption except for the energy penalty. Again, an assessment of these costs would be determined under the §122.21(r)(10) demonstration” (79 Fed. Reg. 158, p. 48370).
2 “EPA’s review of emissions data … suggests that impacts from these pollutant discharges could be significant. These include the human health and welfare and global climate change effects—all associated with a variety of pollutants that are emitted from fossil fuel combustion” (79 Fed. Reg. 158, p. 48341).
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Figure 2: Effects of Operating Cooling Towers—Backpressure, Pumps Operation,
and Fans Operation
When there are important efficiency effects, these lead to variable hourly unit-level
efficiency changes and system-level cost and emission impacts. The evaluated cooling tower
retrofits are specified to operate with the existing condenser and turbine configuration. The
implication is that there will be the potential for important backpressure effects. Based on cooling
tower and condenser parameters, water temperatures to unit performance, local meteorological
data (wet bulb), and estimated inlet water temperatures, estimates of hourly capacity impacts
have been developed in the hourly energy penalty study.
As the hourly energy penalty evaluation describes, differences between once-through
water temperatures and closed-cycle temperatures lead to capacity/output losses in nearly all
hours of the year. Pump and fan requirements add an additional load. Subtracting these from
the capacity identified with backpressure changes reveals the capacity available when operating
cooling towers.
Veritas-0112
System & Unit Efficiency &
Capacity Changes
Backpressure
Pumps Operation
Fans Operation
Environmental Impacts (Acid Rain)
Health Impacts (COPD)
Physical Change System Effects Social Cost/Benefit Categories (r)(10)
Property ValuesIncreased Decibels
(12)(i)—Energy Consumption
(12)(iii)—Emissions Health and Environment
(12)(iv)—Noise Changes
Noise
Shareholders
Ratepayers
Economic Impacts (Jobs, Taxes)
Electricity Price & Output Changes
Must 2
(10)(iii)—Outages and Other
Stack Emission Changes—Pollutant
Emissions
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Power System The outage and operational implications described previously are initial physical effects.
These physical effects would be registered in the power system as increases in the costs of
meeting load—i.e., social costs. Accordingly, understanding how these physical effects would
ultimately be reflected as social costs requires considering the relevant power system and
AWPP’s operations.
The outage and operational implications described previously are initial physical effects.
These costs would be reflected in the power system as social costs. Understanding how these
physical effects would ultimately be reflected as social costs requires considering the relevant
power system vis-a-vis AWPP owners.
AWPP is geographically located within Zone 6 of the Midcontinent Independent System
Operator (MISO) regional transmission organization. Headquartered in Carmel, Indiana, MISO
provides electric reliability and coordination services in nine geographically defined local resource
zones across fifteen states and Manitoba, Canada. Excess generation at AWPP is bid into Zone
6 and dispatched at least cost to participating members. Figure 3 presents MISO and Zone 6.
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Figure 3: MISO and Zone 6
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Power System Simulation Power system effects from capacity losses are identified by specifying relevant Baseline
and Counterfactual conditions and then simulating outcomes using the MISO Zone 6 module of
Veritas’ 316(b)-focused power system model—the Environmental Policy Simulation Model
(EPSM) (Veritas Economics 2011). Figures 4 and 5 provide a conceptual illustration of EPSM’s
modeling process. In these figures, the vertical bars represent generating units. The height of
each bar represents each unit’s marginal cost and the width represents its capacity. The figures
represent an individual hour out of the 8,760 hours in a year. System electrical load for that hour
is represented by the green line.
Figure 4 represents market outcomes under Baseline conditions. The market clearing
price is set where load intersects the dispatch order (slightly below $50 per MWh). The dispatched
units (in grey) all produce electricity at this price or less. The units that are not dispatched (in
white) are all more expensive to operate. The total cost of meeting load is represented by the
area of the shaded units. An operating unit (or equivalently an amount of generating capacity)
that is to be taken off-line is identified.
Figure 4: Electricity Market Under Baseline Conditions
Veritas-0107
80
Generating Units
10
Cos
t per
Hou
r (D
olla
rs)
70
60
50
40
30
20
0
Market supplyMarket demand
Legend:
90
Unit to be Removed
Less Expensive to Operate More Expensive to Operate
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Figure 5 depicts the power system outcomes when this previously operating capacity is
no longer available. As this figure indicates, when a previously operating generation capacity is
removed from the stack, previously more expensive units “shift” to the left. Additional capacity
must operate to meet the existing load (which is fixed in this one-hour example). During other
time periods (not pictured), load moves in and out. Power is more expensive to generate at all
load levels above the generation cost of the previously operating unit (slightly under $40 in Figure
4). Additional outcomes include changes in fuel consumption and emissions as different units
operate.
Figure 5: Electricity Market Under With-Regulation Conditions that Reduce Capacity
Veritas-0134
Baseline supplyWith regulation supply
Legend:
80
10
Cos
t per
Hou
r (D
olla
rs)
70
60
50
40
30
20
0
90
Less Expensive to Operate More Expensive to Operate
Generating Units
Demand
The circled area is an input to social costing (r)(10)(iii)
Changes in energy consumption (r)(12)(i) and emissions (r)(12)(iii) and Must 2 come from this effect, as well
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Quantitative Evaluation The conceptual process described in Section 1 is implemented for AWPP by carrying out
the following steps within EPSM’s Zone 6 power system module:
1. Estimate hourly energy penalty
2. Specify total 2015 hourly load for Zone 6.
3. Calibrate Zone 6 module consistent with 2015 load and 2015 AWPP operations.
4. Create scenarios representing AWPP conversion and ongoing operations.
5. Run EPSM to identify counterfactual dispatch.
6. Calculate differences in fuel consumption and costs.
These steps are implemented as follows.
Estimate Hourly Energy Penalty The energy penalty evaluation is an important input to a number of studies necessary for
the 122.21(r)(12) report and also social costs that must be studied under 122.21(r)(10). Energy
penalties arise from “slightly lower generating efficiency attributed to higher turbine backpressure
when the condenser is not replaced with one optimized for closed cycle operation when retrofitting
existing units” (79 Fed. Reg. 158, 48341). Studying energy penalty effects is important because:
(1) They relate directly to energy consumption, which must be studied under (r)(12)(i).
“The study must include the following: Estimates of changes to energy consumption, including but not limited to auxiliary power consumption and turbine backpressure energy penalty” (§122.21(r)(12), 79 Fed. Reg. 158, page 48428).
(2) They produce indirect and direct social costs, which must be studied under (r)(10).
“EPA is using energy penalty to mean only the opportunity costs associated with reduced power production due to derating (turbine backpressure)” (79 Fed. Reg. 158, 48370).
“… the social cost of the energy penalty is the cost of generating the electricity that would otherwise be available for consumption except for the energy penalty. Again, an assessment of these costs would be determined under the §122.21(r)(10) demonstration” (79 Fed. Reg. 158, 48370).
(3) They affect air emissions, which must be studied under (r)(12)(iii).
“…increased air emissions … due to the energy penalty” (79 Fed. Reg. 158, 48341)
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“The study must include the following: … Estimates of air pollutant emissions and of the human health and environmental impacts associated with such emissions. (79 Fed. Reg. 158, 48428)
(4) These air emissions lead to environmental, health, and social cost (welfare effects),
which must be studied under §122.21(r)(12)(iii) and (r)(10):
“…due to the energy penalty when retrofitting to cooling towers” related to “human health, welfare, and global climate” (79 Fed. Reg. 158, 48341).
“Estimates of air pollutant emissions and of the human health and environmental impacts associated with such emissions” (79 Fed. Reg. 158, 48428).
The required studies under (r)(12) are described as “a detailed, facility-specific
discussion.” Both (r)(10) and (r)(12) reports are subject to peer review (79 Fed. Reg. 158, 48368).
Energy efficiency impacts result in important social costs and can also be an important
determinant in their own right. For example, decision-makers looking ahead to greenhouse gas
requirements may find these effects and their costs more important than comparable capital costs.
Unlike losses from operating pumps and fans, the energy penalty effect is difficult to
generalize. Energy penalties on the hottest days of summer can be higher (EPRI 2011; U.S.
Department of Energy Office of Electricity Delivery and Energy Reliability 2008). The U.S.
Department of Energy estimates that the energy penalty associated with wet cooling towers, for
a fossil plant in the Great Lakes Region, is about 1.5 percent for the annual average temperature
conditions and about 3.1 percent for the hottest months of the year.
Energy Penalty Study Approach The temperature of cooling water affects turbine performance. Colder cooling water
improves unit efficiency (EPRI 2011). Energy penalty effects are due to the different cooling water
temperature of cooling towers compared with that of once-through waterbody temperature. With
once-through cooling, the cooling water is the temperature of the source waterbody. With closed-
cycle cooling, the cooling water temperature is related to cooling tower design characteristics and
atmospheric conditions, in particular wet-bulb temperatures.
As wet-bulb temperatures increase, units cooled by closed-cycle recirculating systems
become less efficient. As noted by EPA, “the cost may be incurred by the facility … or by another
generating unit” (79 Fed. Reg. 158, 48370). Fossil facilities are able to “over-fire” to compensate
for efficiency impacts. Depending upon operational considerations, these facilities may
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experience increased fuel costs and less dramatic capacity reductions.3 Generally speaking,
capacity reductions are experienced when fuel input is at the boiler rated maximum and/or unit
backpressure at the highest tolerated point. At this point, fossil units cannot increase btu input,
and therefore experience capacity reductions. Nuclear units cannot vary fuel input. In both cases,
costs (and environmental effects) of providing lost electricity are incurred by other units.4
Figure 6 depicts the generalized approach for identifying efficiency effects from a closed-
cycle conversion. The approach uses the baseline and counterfactual structure recommended in
EPA (1991) Guidelines for Preparing Regulatory Impact Analysis. The baseline (red) input-output
curve has output limited by line 1 and input (in BTUs) limited at line 2 (number of BTUs per kilowatt
hour.) With an energy penalty from operating the cooling tower, the new input-output curve is
represented by the blue line. If the unit cannot over-fire, the output is limited to where line 2
intersects the blue curve as indicated by line 3. Auxiliary load increases as cooling tower fans
are operated. This is modeled as the shift in capacity to line 4. The original fuel input is maintained
to serve the parasitic load. The resulting input-output curve (5) represents reduced efficiency and
lost net capacity.
3 An important consideration is that both electricity prices and cooling tower performance are correlated with wet-bulb
temperatures. 4 When cooling towers result in lower cooling water temperatures, the opposite occurs.
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Figure 6: Potential for Efficiency Effects from Closed-Cycle Cooling
Because atmospheric conditions vary hourly, these curves move up and down. Figure 7
depicts the energy penalty effect for time periods when the source water body water is cooler than
the cooling tower water. As depicted in the figure, the magnitude of the energy penalty depends
upon fixed (time invariant) technical factors including the slope of the turbine back pressure curve
and cooling tower design parameters. The energy penalty also depends upon factors that vary
somewhat predictably over the course of a year including source waterbody temperatures and
wet bulb temperatures. To evaluate this effect, these are combined in baseline and counterfactual
simulations.
500 MW Output
5,000
00
\
BTU/hr Input
2
1
3
4
Baseline
5
With Cooling Tower(does not over-fire)
With Cooling Tower(does over-fire)
Veritas-0131
Does not over-fire
Does over-fire
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Figure 7: Technical Parameters and Ambient Conditions Underlie Efficiency Effects
500 MW Output
5,000
0
BTU / kWh
Exhaust Pressure: In. Hg. Abs.
10.0
3.02.01.00.0−1.0
0 0.5 1.0 3.0 3.5 4.54.0 5
9.08.07.06.05.04.0
1.5 2.52.0
% Increase in Heat Rate
Turbine Backpressure Curve Heat RateVeritas-0151
Condenser Design
Parameters
Cooling Tower Design
ParametersWet Bulb
Temperature
Exhaust Pressure
Once-Through Condensing Temperature
Closed-Cycle Condensing Temperature
Closed-Cycle Cooling Water Temperature
Once-Through Cooling Water Temperature
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Because this effect exhibits a good deal of nonlinear variability, we characterize it on an
hourly basis.5 Details for doing so (including equations) are presented in EPRI (2011). The
approach follows these general steps:
• Step 1—Collect and compile hourly ambient conditions data.
• Step 2—Calculate approach.
• Step 3—Calculate cooling tower circulating temps.
• Step 4—Estimate the water temperature to heat rate curve
• Step 5—Determine efficiency impacts.
This results in an estimated hourly energy penalty effect that is specific to the atmospheric, water
temperature and operating characteristics of the unit and tower and is relative to baseline
conditions.
Step 1—Source Water and Wet Bulb Data Information requirements for hourly ambient conditions include open-cycle source water
temperatures and wet-bulb temperatures. Ideal information is hourly inlet temperatures measured
at each intake which is not available for this draft report. The nearest available public data are
from the USGS National Water Information System for the Ohio River (USGS 03612600 Ohio
River at Olmstead, IL).6 Figure 8 depicts the data employed for this study.
5 Turbine backpressure curves are steepest and electricity prices are often highest when wet bulb temperatures are
high. 6https://nwis.waterdata.usgs.gov/nwis/uv?cb_00010=on&format=html&site_no=03612600&period=&begin_date=2015
-01-01&end_date=2015-12-31
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Figure 8: Hourly Once-Through Source Water Temperature
Wet bulb data is available from the National Oceanic & Atmospheric Administration’s
(NOAA) National Environmental Satellite, Data, and Information Service. The nearest publicly
available readings are from the Evansville Regional Airport in Evansville, Indiana.7 Hourly wet-
bulb temperatures were developed by collapsing continuous wet-bulb data to hourly data (by
averaging within-hour readings) and are presented in Figure 9.
Figure 9: Hourly Wet Bulb Temperature Data for AWPP
7 The source for this data is available from the following url: https://www.ncdc.noaa.gov/cdo-web/datasets/LCD/stations/WBAN:93817/detail
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Step 2—Calculate Cooling Tower Circulating Temperatures For the cooling tower, the approach is calculated using the following equation (EPRI
2009):
CT Approach = 0.5 * CT Wet Bulb Design + CT Design Approach - 0.5 * Hourly Wet Bulb
where
CT = Cooling Tower CT Wet Bulb Design = 74.7 CT Design Approach = 7 (1)
Cooling tower hourly approaches are depicted in Figure 10.
Figure 10: Hourly Approach Temperatures for AWPP
Step 3—Calculate Cooling Tower Circulating Temps Having information on cooling tower hourly approach and hourly wet bulb, circulating water
temperatures for cooling towers are calculated following EPRI (2009) as:
ThCooling = Th
Wet Bulb + Approachh (2)
where
ThCooling = Hourly cooling tower circulating water temperature
ThWet Bulb = Hourly wet bulb temperature
Approachh = Hourly cooling tower approach temperature.
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Figure 11 depicts cooling water temperatures for once-through cooling (red curve) and closed-
cycle cooling (blue curve).
Figure 11: Cooling Water Temperatures for Once-Through and Closed-Cycle Cooling
for AWPP
Step 4—Estimate the Water Temperature to Heat Rate Curve For fossil plants such as AWPP, plant fuel input varies. Unit output and heat rate varies
with each units’ operational state (e.g., startup versus running) and with cooling water
temperatures and fuel input. For most units, hourly output (in kw) and fuel input (in mmBtu/hr) is
available from the continuous emissions monitoring data (CEMS) collected by EPA’s Air Markets
Program.8 With this information, the relationship between cooling water temperatures and heat rate
can identified by solving for hourly heat rate as Btu/kW-hr and then statistically fitting to water
temperatures.9 Although data for AWPP is not publicly available such evaluations have been
conducted for similar size and age coal units. Statistical modeling for these units consistently
return high levels of statistical significance and water temperature to heat rate relationships similar
to those depicted below.
Heat Rate = 9.10 + 0.010 * Water Temperature
8 Data are located at http://ampd.epa.gov/ampd/. 9 Data preparation procedures include certain validation and cleaning activities, such as eliminating data that appears
to come during ramping periods.
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This equation is depicted graphically depicted below.
Figure 12: Specified Relationship between Water Temperature and Heat Rate
Step 5—Determine Efficiency/ Capacity Impacts Having the hourly cooling water temperatures and the equations that relate cooling-water
temperature to output, these are used to identify heat rate under baseline and with cooling towers
conditions. Figure 13 depicts heat rate for once-through and closed-cycle cooling.
Figure 13: Hourly Heat Rate for AWPP
The red line represents baseline heat rate and the blue line represents the heat rate using
closed-cycle cooling water. As the figures indicate, when using this warmer water, there is a loss
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in efficiency for every hour. Whereas once-through efficiencies relate to source water
temperatures, closed-cycle efficiencies are related to atmospheric heat and humidity (that is, wet
bulb temperatures). This leads to the more variable hourly effect evident in blue.
Specify Hourly Load for Zone 6 Because electricity production costs vary hourly and because important cooling tower
effects are hourly, modeling power system effects at the hourly level is useful. Modeled hourly
load is specified as MISO Zone 6 load for the 8,760 hours of 2015 (Figure 14).
Figure 14: MISO Zone 6 2015 Hourly Load
Operate Model Under Baseline Conditions Under Baseline conditions, operations are consistent with typical operating practices. The
relationship between output and fuel consumption includes variation in cooling water temperature
which lead to an hourly varying heat rate as depicted in Figure 15.
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Figure 15: AWPP Baseline Heat Rate
Under baseline conditions maximum capacity also varies by hour. Operating the model
under these Baseline conditions should produce results that are consistent with historical
operations. Figure 16 depicts Baseline simulated output. This is similar to capacity factors in the
engineering evaluation of 90 percent.
Figure 16: Model Simulated AWPP Output
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Create Scenarios Representing AWPP Conversion and Ongoing Operations Counterfactual scenarios are created for two years. These reflect the physical implications
of an outage for conversation and ongoing operations at AWPP. For the year of the outage, Burns
and McDonnell identified a five-week outage for conversion purposes. This was specified to begin
in mid-March (at hour 1800) and end in late April (at hour 2640). Post-conversion operations
reflect net efficiency reductions from backpressure effects and auxiliary load.
Net output reductions were estimated by Burns and McDonnell as 11.8 MW in the summer
and 9.7 MW in the winter. Gross output reductions were estimated at 2.3 MW in the summer and
0 in the winter. Summer is the warmest 60 percent of hours and winter is the colder remaining
40 percent. Net reductions are attributed to auxiliary load with the expectation that the 2.1 MW
represents reductions in fan power.
Run Simulations to Create Counterfactual Dispatch With the counterfactual conditions set, the model is simulated to identify the counterfactual
outcomes. These counterfactual outcomes are similar to those depicted in Figure 17. As Figure
17 indicates, additional units are dispatched to make up for lost net generation. Under a least cost
dispatch approach, this leads to equal or higher hourly costs. Figure 17 depicts the change in
costs that occur when there is an outage for a conversion followed by the operation of a cooling
tower.
Figure 17: MISO Region 6 Incremental Hourly Costs in Conversion Year
Power System and Off-Site Emissions Study: Warrick January 2018
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As Figure 17 indicates, there is no change in costs up until hour 1800 when the outage
occurs. At this point, offsetting lost generation from AWPP goes up to over $2,000 per hour. After
the plant with cooling tower is back on line (at hour 2641), ongoing incremental costs of over $200
per hour cost are incurred because of auxiliary load and backpressure effects.
A typical year with cooling tower operation has costs like those of the post-conversion
period depicted in Figure 17. However, these effects occur over the entire year as depicted in
Figure 18. As Figure 18 indicates, ongoing costs reach up to $350 per hour.
Figure 18: MISO Zone 6 Incremental Hourly Costs in Typical Year
Calculate Net Differences in Fuel Consumption, Costs, and Emissions The changes in dispatch that lead to cost increases are also associated with changes in
fuel consumption and emissions. Table 1 summarizes these fuel and fuel cost increases as well
as the associated increase in emissions.
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Table 1: Incremental Costs, Fuel Consumption, and Emissions
Technology Metric Conversion
Year Typical Year
Closed-Cycle Cooling Fuel Costs $2.823M $2.304M
Fuel (MMbtu) 690.1K 672.2K
CO2 (tons) 60.1K 52.4K
SO2 (tons) 6.2 5.4
NOx (tons) 25.2 21.1
Fine Mesh Traveling Screens 2.0mm
Fuel Costs $6.8K $9.7K
Fuel (MMbtu) 1.9K 2.8K
CO2 (tons) 154.8 221.5
SO2 (tons) 0.01 0.02
NOx (tons) 0.07 0.09 Cylindrical Wedgewire Screens 2.0mm
Fuel Costs $6.8K $9.7K
Fuel (MMbtu) 2.0K 2.8K CO2 (tons) 154.8 221.5 SO2 (tons) 0.02 0.02 NOx (tons) 0.06 0.09
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References EIA. 2017. U.S. Energy Information Administration, Independent Statistics & Analysis: “Coal
Explained: Coal and the Environment”. Available at https://www.eia.gov/energyexplained/?page=coal_environment. Retrieved on November 15, 2016.
Electric Power Research Institute. 2009. Entrainment Survival: Status of Technical Issues and Role in Best Technology Available (BTA) Selection. Product ID 1019025. Palo Alto, CA: EPRI.
Electric Power Research Institute. 2011. Full-Time/Seasonal Closed-Cycle Cooling: Cost and Performance Comparisons. 1023100. Palo Alto, CA: Electric Power Research Institute. Principal Investigators: Maulbetsch Consulting, DiFilippo Consulting, and Veritas Economic Consulting, LLC.
UCS. 2017. Union of Concerned Scientists: Environmental Impacts of Coal Power: Air Pollution”. Available at http://www.ucsusa.org/clean-energy/coal-and-other-fossil-fuels/coal-air-pollution#.WcEncWwiyUm. Retrieved on November 15, 2016.
U.S. Department of Energy Office of Electricity Delivery and Energy Reliability. 2008. Electricity Reliability Impacts of a Mandatory Cooling Tower Rule for Existing Steam Generation Units. Available at http://www.netl.doe.gov/energy-analyses/pubs/Cooling_Tower_Report.pdf. Retrieved on September 15, 2015.
U.S. Environmental Protection Agency. 1991. Guidelines for Preparing Regulatory Impact Analysis. Available at http://yosemite.epa.gov/ee/epa/eerm.nsf/vwAN/EE-0228A-1.pdf/$file/EE-0228A-1.pdf. Retrieved on August 5, 2014.
Veritas Economic Consulting. 2011. “Veritas Economics Environmental Policy Simulation Model (EPSM).” Working Paper 2011-01. Cary, NC: Veritas Economic Consulting, LLC. Available at http://www.veritaseconomics.com/Working%20Papers/EPSM_201101.pdf.
- MODIFIED TRAVELING SCREEN SKETCHES
Figure C-1: Example of Four Post Thru-Flow Traveling Water Screen
Source: Atlas, 2017
Figure C-2: Example of Typical Basket Assembly
Source: Atlas, 2017
Figure C-3: Example of Typical Spray Wash Assemblies
Source: Atlas, 2017
contract
project
designed
date
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ALCOA 316B STUDY
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A. MYERS
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85014
WARRICK GENERATING STATIONN
WA-SK02
EXISTING INTAKE
POTENTIAL FISH RETURN LOCATION
RETURN LOCATION
POTENTIAL FISH
3/3/17
FISH TROUGH
SCALE IN FEET
30' 60'0
- CYLINDRICAL WEDGEWIRE SCREEN SKETCH
contract
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designed
date
85014
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BU
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ALCOA 316B STUDY
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A. MYERS
12/12/16WEDGEWIRE SCREEN OPTION
WA-SK03
STRUCTURE
INTAKE
ASECTION
SCALE IN FEET
50' 100'0
SCALE IN FEET
25' 50'0
VERTICAL:
HORIZONTAL:
WARRICK GENERATING STATION
SCALE IN FEET
50' 100'0
N
NOTES:
4.
3.
2.
1.
STRUCTUREEXISTING INTAKE
FOR HYDROBURST SYSTEMPROPOSED LOCATION
EL 324'
(SEE NOTE 3)
BLANKING PLATE
EL 395.5'
A
(SEE NOTE 2)
RIVER BOTTOM EL = 324
BUOY (TYP)
AIR LINE
WARM WATER RECIRC
DURING DESIGN PHASE.
SUPPORTED BY PIPE PILES. DETAILS WILL NEED TO BE COORDINATED WITH USACE
NEW SCREENS AND PIPING WILL LIKELY BE MOUNTED ON A STEEL FRAME AND
STRUCTURE.
BLANKING PLATE TO BE SUPPORTED FROM EXISTING BAR SCREEN SUPPORT
IMPROVEMENTS. BATHYMETRY OUTSIDE OF INTAKE CHANNEL IS UNKNOWN.
BATHYMETRY BASED ON DWG A-105721-PE CIRCULATING WATER INTAKE CHANNEL
SCREEN SIZE BASED ON 400,000 GPM INTAKE CAPACITY.
LOW WATER EL = 357.46
6' DIA PIPE
10' DIA INTAKE PIPE
(96" DIA x 317" LENGTH, TYP)
CYLINDRICAL SCREEN
2-MM MESH
Burns & McDonnell World Headquarters 9400 Ward Parkway
Kansas City, MO 64114 O 816-333-9400 F 816-333-3690
www.burnsmcd.com