Molten Salt Power Tower Cost

Model for the System Advisor

Model (SAM)
Craig S. Turchi and Garvin A. Heath
National Renewable Energy Laboratory

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Technical Report
NREL/TP-5500-57625
February 2013

Contract No. DE-AC36-08GO28308

 Molten Salt Power Tower Cost
Model for the System Advisor
Model (SAM)
Craig S. Turchi and Garvin A. Heath
National Renewable Energy Laboratory
Prepared under Task No. SM12.6030

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

National Renewable Energy Laboratory Technical Report

15013 Denver West Parkway NREL/TP-5500-57625
Golden, Colorado 80401 February 2013
303-275-3000 • www.nrel.gov
Contract No. DE-AC36-08GO28308
 NOTICE

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Table of Contents
Summary ...................................................................................................................................................... 1

Background and Motivation ....................................................................................................................... 1

Objectives .................................................................................................................................................... 2

Approach...................................................................................................................................................... 2
Direct Cost Categories............................................................................................................................ 4
Indirect Costs .......................................................................................................................................... 5
Impact of Labor Cost .............................................................................................................................. 6
Power Tower Cost Model Spreadsheet and Reference Plant ................................................................. 7

Conclusions ................................................................................................................................................. 9

References ................................................................................................................................................. 10

Appendix A – Power Tower System Subcategories for SAM Model ................................................... 11

Appendix B – SAM-2012-11-30 / Excel Exchange Variables ................................................................. 13

Appendix C – Financial Assumptions Used for SAM Power Tower Reference Plants ...................... 14

Appendix D – WorleyParsons Subcontract Report: Power Tower Plant Cost and Material Input to
Life Cycle Assessment (LCA)............................................................................................................ 15

iv
Summary
This report describes a component-based cost model developed for molten-salt power tower solar
power plants. The cost model was developed by the National Renewable Energy Laboratory
(NREL), using data from several prior studies, including a contracted analysis from
WorleyParsons Group, which is included herein as an Appendix. The WorleyParsons analysis
also estimated material composition and mass for the plant to facilitate a life cycle analysis of the
molten salt power tower technology. Details of the life cycle assessment have been published
elsewhere [1].

The cost model provides a reference plant that interfaces with NREL’s System Advisor Model or
SAM. The reference plant assumes a nominal 100-MW e (net) power tower running with a nitrate
salt heat transfer fluid (HTF). Thermal energy storage is provided by direct storage of the HTF in
a 2-tank system. The design assumes dry-cooling. The model includes a spreadsheet that
interfaces with SAM via the Excel Exchange option in SAM. The spreadsheet allows users to
estimate the costs of different-size plants and to take into account changes in commodity prices.
This report and the accompanying Excel spreadsheet can be downloaded at
https://sam.nrel.gov/cost.

Background and Motivation

The Solar Advisor Model was developed to assist solar stakeholders in assessing the
performance and cost of photovoltaic (PV) and concentrating solar power (CSP) electricity
generation systems. The program has since expanded to cover additional renewable energy
technologies and been renamed the System Advisor Model (SAM). SAM incorporates modules
that estimate the performance of different PV and CSP systems based on design parameters and
climate files that include solar and weather data for the selected location. As of this report, the
current SAM version is 2012-11-30, available at https://sam.nrel.gov/. SAM also includes
algorithms to estimate the levelized cost of electricity (LCOE) based on a variety of selectable
financial and incentive assumptions. Essential inputs of the LCOE calculations include the
estimated installed cost and operating cost of the technology.

In 2010 NREL released a cost model for parabolic trough systems that was designed to interface
with SAM [2]. This was followed in 2011 with a life cycle assessment for a parabolic trough
power plant with 6 hours of thermal energy storage [3]. These reports, and the associated SAM
case, provided a performance, cost, and materials life cycle assessment for the most common
CSP technology in the marketplace.

System performance projections suggest that power tower, aka central receiver, power plants can
produce power for lower cost than existing oil-HTF parabolic trough systems [4]. Consequently
there is growing commercial interest in power tower systems. Molten salt power towers were
demonstrated in the U.S. by the 10 MW Solar Two project in the late 1990s [5]. The HTF at
Solar Two, and for salt towers since, is a 60 wt%, sodium nitrate, 40 wt% potassium nitrate
blend commonly known as “solar salt.” Molten salt towers incorporate direct storage of the HTF
in hot- and cold-salt storage tanks to provide thermal energy storage and decouple solar energy
collection from electricity production. The design powers a Rankine steam thermal cycle at
temperatures and pressures consistent with that used in coal-fired power systems, allowing for
use of well-developed thermodynamic power cycles running at gross conversion efficiencies of

1
circa 42%. The current state-of-the-art is embodied in the 19.9-MW e Gemasolar Tower that was
commissioned in Spain in 2011 [6]. In the US, the 110 MW e Crescent Dunes Solar Project is
under construction near Tonopah, Nevada [7].

This report summarizes the recent size and cost studies, funded by the U.S. Department of
Energy (DOE), for molten salt power towers. SAM is the DOE’s primary tool for CSP
performance and cost analysis. The paper includes a SAM-compatible cost model that provides
component-level costs and scaling parameters to adjust plant size.

Objectives
The objectives of developing the power tower cost model spreadsheet include:

• Creating a model that allows SAM users to look at the cost impact of individual
components of a typical power tower plant. For example, mirror manufacturers wish to
know how much of the total plant cost is due to the cost of the reflector materials.
• Providing a framework to account for fluctuations in commodity prices over time to keep
the cost model current by incorporating appropriate cost indices for the different cost
components.
• Providing a framework to adjust cost data for changing scale in the various system
components.
• Providing a framework to adjust cost data for different labor rates associated with
different project sites.
The result of these objectives is a spreadsheet model that allows users to update costs for changes
in technology or markets. The spreadsheet is designed to interface with the Molten Salt Power
Tower Model in SAM-2012-11-30. Users are encouraged to customize the spreadsheet model for
their individual purpose.

Approach
In March 2010, the DOE and Sandia National Laboratories hosted a Power Tower Technology
Workshop that included participation of industry, the national laboratories, and DOE. At the
workshop, areas of discussion included the current status of power tower technology, technology
improvement opportunities, and cost-reduction goals for power tower systems and subsystems.
The findings of this exercise were later published as the Power Tower Technology Roadmap and
Cost Reduction Plan [8], hereafter referred to as the “Roadmap.” The Roadmap provided a
system-level assessment of the costs for a current molten-salt power tower, with the major
systems defined as shown in Figure 1.

Two other recent studies provided useful size and cost information for the SAM model. In 2010,
a contract report by Abengoa Solar documented the estimated cost for power towers using
supercritical coolants [10]. This report included size and cost information for the current state-of-
the-art molten salt power tower. Elements of this report were used in the current cost model. The
second study was a tower cost and material analysis performed by WorleyParsons Group Inc.
(Denver, CO).

2
In 2010 NREL published a cost study on parabolic trough plants that was undertaken via contract
with WorleyParsons. WorleyParsons was selected as an engineering firm with comprehensive
services related to all aspects of project development, environmental impact assessment, detailed
design, procurement, construction, and operations & maintenance of renewable energy power
plants, exemplified by their history of engineering design and cost support for multiple
renewable energy and conventional power projects in the United States and abroad. NREL
provided WorleyParsons with nominal design specifications for the reference plant, and the
contractor completed a conceptual design and cost assessment of a parabolic trough plant with
wet cooling and optional dry cooling. WorleyParsons also provided the material composition and
mass data necessary for NREL’s life cycle analysis of the parabolic trough design.

Figure 1. Schematic of a molten salt power tower showing major subsystems [8,9]. Heliostat count
is based on WorleyParsons study case.
In 2011, WorleyParsons was contracted to perform a similar analysis for the molten salt power
tower design. Using the same contractor ensured that the two CSP studies would be consistent in
their structure and methodology. Similar to prior parabolic trough case, installed cost data for
components of the molten salt power tower design were provided by WorleyParsons under their
contract. Because the previously mentioned sources provided cost information, the primary
objective of the WorleyParsons study was to develop the mass and material estimates necessary
for a life cycle assessment of the molten salt power tower design. WorleyParsons also estimated
the cost of many of the power tower plant components. One exception was the solar field, which
was excluded from the WorleyParsons scope of work. The WorleyParsons analysis used the

3
same system definitions (Figure 1) to be consistent with the prior work. These systems also
represent the major cost categories in the SAM molten salt power tower model.

Direct Cost Categories

Each of the systems shown in Figure 1 was divided into a number of components for the SAM
power tower cost model and costs for system components were estimated in the following
manner:

• Collector System. The solar, or heliostat, field was subdivided into the following
components: mirrors; drives; pedestal, support and foundation; controls and wired
connections; field wiring and foundations labor; installation and checkout. The cost
breakout for each component followed the estimate provided in the Roadmap for the
148m2 ATS heliostat with a 5000/unit per year production level. The cost element for
“manufacturing facilities and profit” in the Roadmap was proportioned across the cost
categories. Solar field costs scale linearly with total solar field reflector area. Unlike the
other systems, the design and cost of the solar field system was excluded from
WorleyParsons’ analysis and was based on data from [8,10,11].
• Tower/Receiver System. The tower/receiver system was subdivided into a tower category
including the tower and riser/downcomer piping & insulation and a receiver category
including the receiver, horizontal piping & insulation, cold salt pumps, controls & heat
tracing. This division was necessary because SAM calculates tower and receiver costs
separately. SAM and the cost spreadsheet scale tower components by tower height. SAM
scales all receiver components with receiver area, however, the cost model spreadsheet
scales only the receiver by receiver area. Other receiver components are scaled by
receiver thermal power.
• Thermal Storage System. The thermal storage system was subdivided into six component
costs: hot tank, cold tank, storage media, piping & insulation, foundations, instruments &
controls. TES costs are scaled by TES capacity in MWh-t.
• Steam Generation System. SAM’s cost page includes a “Balance of Plant” category that
allows users to break out plant components from the major categories for analysis
purposes. Following the convention of the Roadmap, the costs for the steam generation
system are segregated from the power generation system and listed under the balance of
plant category. This is convenient for comparing molten salt and direct steam power
towers. The steam generation system includes: evaporator and preheater circulation
pumps; hot salt circulation and transfer pumps; heat exchangers for reheat, evaporation,
and preheating (economizer); steam drum; as well as the associated piping, valves,
insulation, electrical, controls, and foundations associated with that equipment.
• Power Generation System. The power block costs were estimated using data from the
WorleyParsons’ study, adjusted for labor rates costs in southern California, along with
information from [10]. The power block system is divided into 17 component costs as
shown in Appendix A. Power block costs scale with gross turbine capacity.
• Site Preparation. SAM includes an explicit cost category for site preparation. This
category includes clearing and grading land, storm water control, roads and fences,
blowdown evaporation pond, and water supply infrastructure. The tower model bases site

4
 preparation costs on those from the trough plants in [2]. Costs for clearing and grading
were reduced by 90% under the assumption that the heliostat field would not be graded.
Site preparation costs scale with plant land area.
SAM applies an overall contingency on all direct costs. Contingency addresses unforeseen costs
within the project and it is assumed that all contingency will be consumed during the course of
project construction.

Indirect Costs
Indirect costs in SAM are designed to capture non-hardware project costs such as permitting,
land, legal fees, geotechnical and environmental surveys, taxes, interest during construction, and
the owner’s engineering and project management activities. Some of these categories are listed
explicitly, while many are simply lumped into the EPC and Owner Cost category. SAM’s EPC
& Owner Cost percentages are based on a review of cost estimates from nine utility-scale
projects under the federal loan guarantee program. Land cost is estimated at $10,000 per acre.
Sales Tax is approximately equal to the national average – the value has been standardized
across SAM technologies, and SAM assumes sales tax is applied to 80% of the total direct costs.
Most CSP plants take more than one year for construction. SAM’s default financing costs
assume a 24-month construction period with a 5% loan for the full overnight construction costs.
This translates into approximately an additional 6% cost to the project. Combined, the multiplier
for indirect costs (EPC & Owners Costs, Land, Sales Tax, and Financing during construction)
within SAM is approximately 25.8%. The cost input summaries for the Roadmap, the
WorleyParsons’ study and SAM are shown in Table 1 for comparison.

5
Table 1. Cost summaries from Tower Roadmap, the WorleyParsons analysis, and the current SAM
default parameters for a molten salt power tower. The SAM default values aggregate information
from several sources.
Direct Cost (DC) Category Units Tower WorleyParsons SAM
Roadmap [8] Group 2012-11-30
(Appendix) Default Values
Assumed location - Daggett, CA Tucson, AZ Daggett, CA
Site Improvements $/m2 - 20 15
Solar Field $/m2 200 n/a 180
Balance of Plant $/kW 350 365 350
(Steam Generation
System)
Power Block (dry cooled) $/kW 1000 1000 1200
Fossil Backup $/kW - - -
Storage $/kWh-t 30 35.5 27
Tower / Receiver $/kW-t 200 142‡ 173‡
Contingency % of DC Included in 9.5 7
above
Indirect Cost Category
EPC & Owner Costs % of DC 25 - 11
Land $/acre - - 10,000
Sales Tax Rate applied to 7.75% - 5.0%
80% of DC (CA) (US avg)
Financing during % of overnight - - 6.0
Construction costs
Combined Indirects % of DC 31.2% - 25.8%
O&M Cost Category
Fixed Annual Cost $/yr 0 - 0
Fixed Cost by Capacity $/kW-yr 70 - 65
Variable Cost by Gen. $/MWh 3 - 4
‡ SAM estimates tower and receiver costs separately. This value is calculated by summing the total tower and
receiver cost (excluding contingency) and dividing by the rated receiver thermal power.

Impact of Labor Cost

The SAM default case follows the Roadmap selection of Daggett, CA, as the reference plant
location. Accordingly the spreadsheet model assumes southern California labor rates. Labor rates
can be changed to other locations by adjusting the Labor Cost Factor given as User Variable 2 in
SAM. Labor rates and categories are taken from the U.S. Bureau of Labor under NAICS 221100,
Electric Power Generation, Transmission and Distribution, May 2011 [12]. Because the power
tower reference plant assumes southern California labor rates, the Labor Cost Factor for
California is normalized to 1.0 (in contrast to the parabolic trough model where Phoenix labor is
normalized to 1.0). For the tower model the corresponding national average is 0.63 and the value
for Tucson, AZ is 0.47. (Private industry, mean hourly wage, union labor, Riverside, CA versus
US national average and nonunion Tucson, AZ).

Users are encouraged to supply their own labor rate correction factor via User Variable 2 in
SAM. The assumed labor rate has a significant effect on installed system cost and operating
costs.

6
Power Tower Cost Model Spreadsheet and Reference Plant
The spreadsheet contains cost information for two plants: a “reference plant” and a “project
plant.” The reference plant matches the default molten salt power tower in SAM 2012-11-30.
The reference plant (highlighted in yellow) is defined as a 115-MW e gross power tower with 10
hours of thermal energy storage located in southern California. The solar multiple was set to 2.4,
and SAM was used to calculate the associated solar field size. The TMY2 climate file for
Daggett, CA was employed. Costs for the reference plant come from a variety of sources as
described above. In some cases the specific costs listed are an aggregate from multiple sources.
This process is used to incorporate opinions of multiple developers and as a mean of updating
technology costs based on advances since the referenced cost study dates.

The spreadsheet cost model is designed to interface with SAM, but it may be used directly
without calling SAM. The project plant provided in the spreadsheet (highlighted in orange)
represents the user’s specific scenario. Data for the project plant can be entered by the user into
the orange cells on the SAM Exchange worksheet. If linked to SAM, these cells are populated
automatically during SAM’s Excel Exchange process. In either event, the spreadsheet calculates
the project plant costs by scaling based on the size of project plant components compared to
those of the reference plant. As supplied, the project plant is set to match the reference plant
case.

The spreadsheet includes cost indices to escalate component and labor costs for inflation and
market factors. Cost indices in the spreadsheet model are based on the Chemical Engineering
Plant Cost Index published monthly in Chemical Engineering Magazine and available online at
http://www.che.com/. Additional cost indices are taken from the U.S. Bureau of Labor’s
Producer Price Index (PPI), which can be tracked on line at http://www.bls.gov/ppi/. The
spreadsheet includes a PPI index for synthetic ammonia to represent the nitrate salt storage
media in trough plants. This public index tracks the nitrogen fertilizer market; however, vendor
data suggest it may not be an accurate surrogate for solar salt prices. An estimate of historic solar
salt prices is also included. Salt price has a large impact on overall storage costs, and users are
encouraged to check with vendors for these prices. Users may also customize the spreadsheet by
choosing alternative cost indices. Within the spreadsheet, a specific cost index is selected by
changing the Matl cost esc Factor or Labor cost esc Factor.

The cost model spreadsheet interfaces with SAM through the Excel Exchange linkage. (Note to
Mac users: the Excel Exchange option does not function on Mac computers.) Excel Exchange
allows users to connect any input variable in SAM to a cell or range of cells in a Microsoft Excel
workbook. This feature allows users to use external spreadsheet-based cost and performance
models to generate values for SAM input variables. User-defined input variables can also share
values with external workbooks. The cost model uses four user variables. Exchange variables are
listed in Appendix B. To access Excel data exchange in SAM, first click Configure Simulations
to view the Configure Simulation page:

7
Then click Excel Exchange to display the Excel data exchange options:

Figure 2. Excel Exchange page in SAM 2012-11-30.

The SAM Excel Exchange variable entry page is shown in Figure 2; more information on
customizing SAM with Excel Exchange can be found in the SAM help files. When retrieving
data from Excel via the SAM Excel Exchange, the cells in Excel must not have $ or %
formatting. Such formatting will cause an error message in SAM. Also, note that after the
exchange process, the spreadsheet does not retain the values read in from SAM; in contrast, the
SAM case does retain the values pulled from the spreadsheet.

Examples of the use of the cost spreadsheet with SAM are shown in Table 2 below. The four
columns list results for the SAM default molten salt power tower in Daggett, CA, the same
default case supplied with the cost spreadsheet, the default tower design moved to Arizona, and a
smaller power tower located in Daggett, CA. The impact of lower labor rates can be seen for the
Arizona location. The smaller tower case highlights the advantage of scale with the CSP
technology. A smaller plant incurs greater installed and operating costs per capacity that lead to a
larger LCOE.

8
 Table 2. SAM modeling results using the spreadsheet cost model.
SAM SAM
2012-11-30 2012-11-30 Arizona
Default Spreadsheet Labor Rates Smaller
Design Parameters Case Model Case Tower Case
Power block gross rating (MW e ) 115 115 115 20
Thermal storage at design point (hours) 10 10 10 15
Solar multiple 2.4 2.4 2.4 2.8
Design conditions dry-bulb temperature 42 42 42 42
(°C)
Location (weatherfile) Daggett, CA Daggett, CA Tucson, AZ Daggett, CA
Size Parameters
Tower height (m) 203 203 203 93
Receiver design thermal power (MW t ) 670 670 670 136
Solar Field area (m2) 1,289,000 1,289,000 1,289,000 260,000
Thermal storage salt volume (m3) 13,000 13,000 13,000 3,390
Performance Outputs from SAM
Net Capacity (MW e ), annual average 105 105 105 18
Annual net electricity generation (MWh) 539,700 539,700 519,400 109,200
Capacity factor (based on MW e net) 58.9% 58.9% 56.7% 69.2%
Estimated land area (acre) 1,953 1,953 1,953 447
Cost Outputs from SAM
Total Overnight Installed Costs ($/kW e, net ) 7,490 7,500 6,870 11,000
Total Project Installed Costs ($/kW e, net ) 7,910 7,920 7,250 11,700
LCOE (¢/kWh), real with 30% ITC 11.8 11.9 11.0 17.1
LCOE (¢/kWh), real with 10% ITC 14.9 15.0 14.0 20.6

Conclusions
A component-based cost model has been developed for SAM’s molten-salt power tower model.
The cost model spreadsheet interfaces with SAM through the Excel Exchange function. Costs are
based on a nominal 100-MW e (net) reference plant running with a nitrate salt heat transfer fluid
(HTF). Thermal energy storage is provided by direct storage of the HTF in a 2-tank system, and
the design assumes dry cooling. The spreadsheet allows users to estimate the cost of different-
size plants and to take into account changes in commodity prices, and labor rates for different
project locations. This report and the accompanying Excel spreadsheet can be downloaded at
https://sam.nrel.gov/cost.

9
References
1. Whitaker, M.B., G.A. Heath, J.J. Burkhardt, and C.S. Turchi, “Life Cycle Assessment of a
Power Tower Concentrating Solar Plant and the Impacts of Key Design Alternatives,”
submitted to Environ. Sci. Technol. 2013.
2. Turchi, C.S., “Parabolic Trough Reference Plant for Cost Modeling with the Solar Advisor
Model (SAM),” NREL/TP-550-47605, July 2010.
3. Burkhardt, J.J., III; G.A. Heath, and C.S. Turchi, “Life Cycle Assessment of a Parabolic
Trough Concentrating Solar Power Plant and the Impacts of Key Design Alternatives,”
Environmental Science & Technology, Vol.45, Iss.6; p.2457-2464 (2011).
4. Turchi, C.S., M. Mehos, C.K. Ho and G.J. Kolb, “Current and Future Costs for Parabolic
Trough and Power Tower Systems in the US Market,” NREL/CP-5500-49303, presented at
SolarPACES 2010, Perpignan, France, September 21-24, 2010.
5. Pacheco, J.E., “Final Test and Evaluation Results from the Solar Two Project,” SAND2002-
0120, 2002.
6. Burgaleta, J.I, S. Arias, and D. Ramirez, “Gemasolar, the First Tower Thermosolar
Commercial Plant with Molten Salt Storage, SolarPACES 2011, Granada, Spain, September
20-23, 2011.
7. http://www.solarreserve.com/what-we-do/csp-projects/crescent-dunes/
8. Kolb, G.J., C.K. Ho, T.R. Mancini, and J.A. Gary, “Power Tower Technology Roadmap and
Cost Reduction Plan,” SAND2011-2419, Sandia National Laboratories, Albuquerque, NM,
April 2011.
9. Reilly, H.E, and G.J. Kolb, “An Evaluation of Molten-Salt Power Towers Including Results
of the Solar Two Project,” SAND2001-6674, Sandia National Laboratories, November 2001.
10. Kelly, B., “Advanced Thermal Storage for Central Receivers with Supercritical Coolants,”
DOE Contract Report under Grant DE-FG36-08GO18149, June 2010.
11. Kolb, G. J., S. A. Jones, M. W. Donnelly, D. Gorman, R. Thomas, R. Davenport, and R.
Lumia, “Heliostat Cost Reduction Study,” SAND2007-3293, Sandia National Laboratories,
Albuquerque, NM, June 2007.
12. National Compensation Survey, U.S. Department of Labor, May 2011, accessed December
2012 from http://www.bls.gov/ncs/summary.htm
13. Pacific Gas & Electric Company, “Solar Central Receiver Technology Advancement for
Electric Utility Applications,” Phase 1 Topical Report, Report No. 007.2-88.2, San
Francisco, CA, September 1988; Arizona Public Service Company, “Utility Solar Central
Receiver Study,” Report No. DOE/AL/38741-1, November 1988; Alternate Utility Team,
“Utility Solar Central Receiver Study,” Report No. DOE/AL/38741-2, September 1988.
14. Kistler, B.L., “A User's Manual for DELSOL3: A Computer Code for Calculating the Optical
Performance and Optimal System Design for Solar Thermal Central Receiver Plants,”
SAND86-8018, Sandia National Laboratories, November 1986.
15. Gilman, P., 2010. Solar Advisor Model User Manual, latest ed. National Renewable Energy
Laboratory, Golden, Colorado. See also URL www.nrel.gov/analysis/sam/publications.

10
Appendix A – Power Tower System Subcategories for
SAM Model
DIRECT CAPITAL COSTS
Site - Site Preparation
Site - Clearing & Grubbing
Site - Grading, Drainage, Remediation, Retention, & Detention
Site - Evaporation Pond
Site - Roads, Parking, Fencing
Site - Water Supply Infrastructure

Heliostat Field - Mirrors

Heliostat Field - Drives
Heliostat Field - Pedestal, Mirror Support, Foundation
Heliostat Field - Controls and Wired Connections
Heliostat Field - Field Wiring & Foundations Labor
Heliostat Field - Installation & Checkout

Tower - Tower
Tower - Riser and Downcomer Piping & Insulation

Receiver - Receiver
Receiver - Horizontal Piping & Insulation
Receiver - Cold Salt Pump(s)
Receiver - Controls, Instruments, Heat Trace
Receiver - Spare Parts

TES - Cold Tank(s)

TES - Hot Tank(s)
TES - Media
TES - Piping, Insulation, Valves, & Fittings
TES - Foundations & Support Structures
TES - Instrumentation & Controls

Fossil Backup

SAM BOP Defined as Steam Generation System

BOP - Steam Generation Heat Exchangers and Equipment
BOP - Hot Salt Pump(s)
BOP - Steam Piping, Insulation, Valves, & Fittings
BOP - Electrical, Instrumentation, and Controls System
BOP - Foundations & Support Structures

Power Plant - Steam Turbine Generator Island

Power Plant - Blowdown System
Power Plant - Cooling Systems

11
Power Plant - Condensate System
Power Plant - Feedwater System
Power Plant - Auxiliary Cooling Water System
Power Plant - Steam Piping, Insulation, Valves, & Fittings
Power Plant - Fuel Gas Handling & Metering System
Power Plant - Water Treatment System
Power Plant - Power Distribution Systems
Power Plant - Back-up Power Systems
Power Plant - Instruments and Controls System
Power Plant - Fire Protection System
Power Plant - Foundations & Support Structures
Power Plant - Buildings
Power Plant - BOP Mechanical Systems
Power Plant - BOP Electrical Systems

12
Appendix B – SAM-2012-11-30 / Excel Exchange
Variables
Variables out from SAM to Excel: Excel Cell Comments
Design Turbine Gross Output h11
Design Thermal Power h12 Power block design thermal power
Full Load Hours of TES h13
Total Land Area h14
Total Reflective Area h15 Total solar field area
Receiver Design Thermal Power h16
Area h17 Receiver area, shown on SAM Costs page
Tower Height h18
Inflation Rate h19
Sales Tax h20
User Variable 1 h21 Analysis year
User Variable 2 h22 Labor_cost_factor
Variables in to SAM from Excel:
Fixed Tower Cost e11 Cost Factor for SAM's scaling equation
Receiver Reference Cost e12 Cost Factor for SAM's scaling equation
Receiver Reference Area e13 Cost Factor for SAM's scaling equation
Receiver Cost Scaling Exponent e14 Cost Factor for SAM's scaling equation

Site Improvement Cost per m2 i26

Heliostat Field Cost per m2 i27

Storage Cost per kWht i30

Fossil Backup Cost per kWe i31
Balance of Plant Cost per kWe i32
Power Block Cost per kWe i33
Contingency i34

EPC Costs % Direct i37 Percent of direct costs

Land Costs acre i38 $ per acre
Sales Tax Percentage of Direct Costs i39

Fixed Annual Cost i43

Fixed Cost by Capacity i44
Annual O&M variable cost, used to calc
User Variable 5 i45 Variable Cost by Generation
Fossil Fuel Cost i46
User Variable 6 i47 Estimated O&M labor force

13
Appendix C – Financial Assumptions Used for SAM
Power Tower Reference Plants

14
Appendix D – WorleyParsons Subcontract Report:
Power Tower Plant Cost and Material Input to Life
Cycle Assessment (LCA)

15
Power Tower Plant Cost and Material
Input to Life Cycle Assessment (LCA)

NREL Task 8, Final Report-PUBLIC

NREL-8-ME-REP-0002 Rev 2

Prepared for:
National Renewable Energy Laboratory (NREL)

Prepared by:
WorleyParsons Group, Inc.
1687 Cole Blvd, Suite 300
Golden, Colorado 80401 USA

October 08, 2012

POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

NOTICE
The information presented in this document was compiled and
interpreted exclusively for the purposes stated in the document
introduction. WorleyParsons provided this report for NREL solely for
the purpose noted above.

WorleyParsons has exercised reasonable skill, care, and diligence to

assess the information acquired during the preparation of this report,
but makes no guarantees or warranties as to the accuracy or
completeness of this information. The information contained in this
report is based upon, and limited by, the circumstances and conditions
acknowledged herein, and upon information available at the time of its
preparation. The information provided by others is believed to be
accurate but cannot be guaranteed.

WorleyParsons does not accept any responsibility for the use of this
report for any purpose other than that stated in the document
introduction and does not accept responsibility to any third party for the
use in whole or in part of the contents of this report. Any alternative
use, including that by a third party, or any reliance on, or decisions
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Any questions concerning the information or its interpretation should be

directed to Robert Pieksma, Project Engineer.

PROJECT 108037-03981
REV DESCRIPTION ORIG REVIEW WORLEY- DATE CLIENT DATE
PARSONS APPROVAL
APPROVAL

0 FINAL Issue-PUBLIC JLS RDB RCP 9 -6-12

J.Straubinger R. Bowers R. Pieksma

1 Revision of Appendices JLS RDB RCP 9-11-12

J.Straubinger R. Bowers R. Pieksma

2 Revision of Construction JLS RDB RCP 10-08-12

Weights J. Straubinger R. Bowers R. Pieksma
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

TABLE OF CONTENTS

1. SUMMARY ........................................................................................................................... 6

2. PROJECT DESCRIPTION ................................................................................................... 6

3. CONCEPTUAL DESIGN ...................................................................................................... 6

4. COST ESTIMATE BASIS ..................................................................................................... 7

4.1 Quantity Development ............................................................................................. 7

4.2 Material and Equipment Pricing ............................................................................... 7

4.3 Construction Labor .................................................................................................. 8

4.4 Clarifications ............................................................................................................ 9

4.5 Exclusions .............................................................................................................. 10

4.6 Tower Cost & Height Formula ............................................................................... 11

5. APPENDICES INFORMATION .......................................................................................... 11

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDICES AND DELIVERABLES

Appendix A – Conceptual Process Flow Diagram (1 page)
Appendix B – Major Equipment List (2 pages)
Appendix C – Power Tower Plant Capital Cost Summary: Materials and Labor (1 page)
Appendix D – Water Usage (1 page)
Appendix E – Specialized Equipment List (1 page)
Appendix F – Other O & M Energy Requirements (1 page)
Appendix G – References (2 pages)
Appendix H – Variable Tower Height Cost Information (1 page)
Appendix I – Total Mass of Plant Construction Summary (2 pages)
Appendix J – O&M Replacement Mass Summary (1 page)

(Appendix number of pages does not include cover page)

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

LIST OF ACRONYMS

ACC – Air Cooled Condenser

AISI – American Iron & Steel Institute
ANSI – American National Standards Institute
ASME – American Society of Mechanical Engineers
ASTM – American Society for Testing and Materials
BLM – Bureau of Land Management
CMU – Concrete Masonry Units (Load-bearing Cinderblock)
CS – Carbon Steel
CSP – Concentrating Solar Power
EPCM – Engineer, Procurement, Construction Management
FRP – Fiberglass (or Fiber) Reinforced Plastic
HTF – Heat Transfer Fluid
HVAC – Heating, Ventilation, and Air Conditioning
LCA – Life Cycle Assessment
MTO – Material Take-off
MW - Megawatt
NREL – National Renewable Energy Laboratory
O & M – Operations & Maintenance
PDC – Power Distribution Center
SAM – System Advisor Model
SGS – Steam Generation System
SS – Stainless Steel
STG – Steam Turbine Generator
TES – Thermal Energy Storage
TIC – Total Installed Cost
WSAC – Wet Surface Air Cooler

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

1. SUMMARY
This report provides the National Renewable Energy Laboratory (NREL) with two objectives. The
first objective is a capital cost estimate for the overnight construction of a state-of-the-art solar
power tower plant in Tucson, AZ. This estimate provides line item material and labor costs for the
individual components of the power plant as well as subsystem costs and a total installed cost
(TIC), excluding the heliostat field. The second objective is to provide input to NREL’s life cycle
assessment (LCA) of this plant which documents the total life cycle emissions, energy payback
time and water consumption. This information includes the estimated size, material composition,
and mass of system components as well as an operations and maintenance (O & M) schedule.
The O&M schedule provides the associated maintenance and consumable material quantities.

This report should be viewed as a high-level assessment with the understanding that site specific
information, optimization, and detailed engineering will affect a LCA of an actual plant. This report
was prepared for public distribution and the cost and LCA information is therefore provided in
summary format. A more detailed confidential report was generated for internal NREL use, which
provides cost at the component and subsystem level along with a LCA breakdown by ASTM
material specification down to the subsystem level.

2. PROJECT DESCRIPTION
This project is based on the design of a state-of-the-art solar power tower that uses molten nitrate
salt as the heat transfer fluid (HTF) and thermal energy storage (TES) media. The plant is
designed to generate ~100MWe net (115MWe gross) to the grid at 230kV using 100% dry cooling
and having 6 hours of molten salt thermal energy storage (TES). The power tower plant
subsystems are comprised of the following:
• Site Improvements
• Heliostat Field (by NREL)
• Tower
• Receiver
• Thermal Energy Storage
• Steam Generation System
• Electric Power Generation System
The subsystem breakout generally follows that described in section 2 of reference [3], listed in
Appendix G.

3. CONCEPTUAL DESIGN
The conceptual design of the plant was based largely on SAND2001-2100 “Solar Power Tower
Design Basis Document”, SAND2001-3674 “An Evaluation of Molten-Salt Power Towers Including
Results of the Solar Two Project” and the SAM model sent to WorleyParsons by Craig Turchi on
2/17/2012; “NREL Power Tower for WP Task 8 study SAM-2011-12-02.zsam”. Many other
references, design tools, standards and specifications were relied upon to conceptually design the
plant, some of which are listed in Appendix G.

A heat & mass balance of the major steam, feedwater and steam generation systems was
performed to establish design flow, temperature and pressure parameters for the associated
equipment and piping. A process flow schematic of the major plant systems is provided in
Appendix A – Conceptual Process Flow Diagram. A major equipment list is provided in Appendix B
– Major Equipment List.

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

NREL provided the thermal transfer capacity, panel quantity, diameter, and height of the solar
receiver and also the panel tube diameter, wall thickness, and solar absorption length. Tube
quantities per panel were calculated from this data and structures were designed to support the
panel tubes and headers. An additional structure attached to the top of the tower was designed to
support the panels, boom crane, salt inlet vessel, salt outlet vessel, salt overflow vessel, and other
auxiliary receiver equipment. The weight of the receiver and equipment, salt piping, heat tracing,
insulation, instrumentation, and wiring was calculated to determine the design load on top of and
inside of the concrete tower. A concrete tower was designed based on the seismic criteria and
typical soils found in the Tucson, AZ area. The tower and receiver include stairs, platforms, and
elevators for personnel and equipment.

4. COST ESTIMATE BASIS

The capital cost estimate is provided in Appendix C - Power Tower Plant Capital Cost Summary:
Materials. The estimate is based on an Engineer – Procure – Construction Management (EPCM)
approach. Engineering and Design, Construction Management, and Start-up & Commissioning
costs are included.

Material Take-off (MTO) and Design Allowances are included in the estimate and are intended to
compensate for the degree of engineering that is incomplete. This is not a contingency; rather it is
a minor allowance included to cover the nominal quantity growth which inevitably occurs as the
design is further developed. Contractor mark-up on bulk materials has been added and reflects the
mark-up that contractors will apply to bulk materials provided under their respective contracts.

The estimate excludes escalation. All costs are presented as overnight 2Q2012 dollars.

Project Contingency addresses unforeseen elements of costs within the current defined project
scope. It is expected that by the end of the project the entire contingency will be spent on either
direct or indirect costs.

4.1 Quantity Development

Equipment quantities for major equipment components are based on preliminary engineering
provided in drawings, flow diagrams, process and instrumentation diagrams (P&ID’s), equipment
lists, and electric one-line diagrams. Major piping networks, such as the molten salt, steam,
feedwater, and condensate systems, were conceptually developed from P&ID’s.

Minor balance of plant equipment not included in the project design documents are based on
similar plant designs previously developed by WorleyParsons. Examples of minor balance of
plant equipment include steam turbine gland steam seal system, condenser air removal system,
steam cycle chemical feed system, service air system, steam / water sampling system, and
compressed air systems. Bulk material quantities were developed for select major systems based
on conceptual routings and sizing where available. Quantities for the balance of plant systems
were developed by scaling from a similarly sized plant to meet specific project requirements.

4.2 Material and Equipment Pricing

Some of the major equipment costs are based on budgetary quotes or pricing from similar project
cost data. The remaining equipment costs and bulk material pricing are based on WorleyParsons’
cost estimating database, which includes recent pricing for similar materials. Most of the
equipment and materials will be transported by truck to the project site.

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

4.3 Construction Labor

Overall construction labor costs include wage rates, installation hours, labor productivity, labor
availability and construction indirect costs.

4.3.1 Wage Rat es

Merit shop wage rates for the Tucson AZ area are based on PAS 2011 Labor Rates for the
Construction Industry (Region 9). Rates are valid to 2Q2012.

4.3.2 Installation Hours

WorleyParsons maintains a database of standard unit installation hours. The database
represents standard installation rates for US Gulf Coast Merit Shop. Equipment setting man-
hours were developed by evaluating estimated weights, equipment size, and number of
components in conjunction with crew sizes and approximated time. Bulk material man-hours are
based on standard unit installation rates. The resultant hours are further adjusted for productivity
(described below).

4.3.3 Labor Producti vit y

The estimate reflects productivity for the Tucson, Arizona area. In evaluating productivity, factors
such as jobsite location, type of work (i.e. new construction) and site size are considered. Labor
productivity factors (multipliers over US Gulf Coast Merit Shop) have been included to reflect
anticipated site specific labor productivity. The productivity for merit shop labor in the Tucson
area is expected to be comparable to USGC resulting in a productivity factor of 1.0.

4.3.4 Labor Availabilit y

Labor is based on a 50-hour work-week (5-10s). The estimate also includes an allowance of
$75/day for travel and per diem. No additional incentives have been included to attract or retain
craft labor. The estimate is based on an adequate supply of qualified craft personnel being
available to staff this project.

4.3.5 Construction Indirect Costs

In addition to base wage rates and fringe benefits, labor costs include construction indirect costs
consisting of:
• Payroll taxes and insurances
• Contractor’s General Liability insurance
• Construction supervision
• Indirect craft labor
• Temporary facilities
• Field office
• Small tools & consumables
• Material handling
• Safety / incentives
• Mobilization / demobilization
• Premium time portion of extended work week
• Craft bussing within the construction site
• Construction rental equipment
• Fuel, oil & maintenance for construction equipment

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

• Contractor’s overhead and profit (on labor-related costs)

4.4 Clarifications

4.4.1 Ci vil / Structural

• The site is relatively flat. No underground obstructions, rock formations, or unusual site
conditions exist.
• All grading will be balanced across the site.
• Earthwork (rough grading) is based on 1 ft of earth movement over the entire solar field
site.
• Site geography is assumed to have an average slope between 1% and 2% and can be
graded with conventional equipment.
• Topsoil removal is not required. The topsoil will be scarified and compacted.
• Approximately 1,568 acres (6,345,496 m²) of land will be cleared and grubbed. Desert
vegetation (shrubs, etc.) covers the entire site.
• De-watering is not required.
• The power block and two (2) radial access roads will be paved (asphalt).
• Soil binder/stabilizer is not included for dust control at solar field roads.
• The entire site will be fenced with 8 foot (2.4 m) high chain link fencing with barbed wire.
• The evaporation ponds will have a double HDPE liner. A leak detection system is
included.
• The detention pond will be unlined with a compacted native soil bottom.
• Concrete foundations are based on 4,000 psi concrete. Piles are not required. Heliostat
piles, if required, are part of NREL scope.
• Concrete foundations are included for all equipment and buildings.
• The steam turbine and ancillary equipment will be indoors.
• Steam turbine, SGS system, electrical, administration & maintenance, and warehouse
buildings are included.
• An on-site heliostat fabrication facility is excluded (NREL scope).
• Sanitary waste will not be piped offsite; rather it will run through a septic tank and run
through an onsite leach field.

4.4.2 Mechanical / Piping

• The steam turbine is housed in the steam turbine building.
• The tower structure is based on a turnkey design, furnish & erect contract.
• The salt fill will be delivered in one-tonne “supersacs”. The cost for salt melting
equipment (temporary) and labor are included. Salt melting energy is excluded in cost
estimate but is provided in Appendix F - Other O&M Energy for LCA information.
• Stress relieving for piping is included as required by code.
• Underground steel pipe is coated and wrapped.
• Expansion loops for piping systems where required are included.
• Water supply will be provided by three water wells, assumed to be located 200 ft from the
heliostat field perimeter.
• Water quality information is unknown and therefore minimal pre water treatment is
included and post treatment is excluded.
• A wind fence is excluded.
• Fire protection equipment is excluded from the solar field. Only power block equipment is
protected.
• Heliostat costs are part of NREL’s scope and not included in this estimate.
• Natural gas piping is not required for this project and therefore not included.

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

4.4.3 Electrical / Instrum entation

• A 13.8kV-230kV generator step-up transformer is included.
• An on-site switchyard with 230kV main circuit breaker and main disconnect switches is
included.
• No transmission lines beyond the switchyard are included.
• The estimate includes auxiliary transformers and station service transformers, the sizing
of which includes the heliostat parasitic load.
• All power and control cabling, wiring and fiber optic for the heliostat field is excluded
(NREL scope). Heliostat drive power converters are also not included.
• Emergency diesel generators are included and their sizing includes heliostat power
consumption.
• Power Distribution Center (PDC) buildings and equipment are included.
• Underground power block area duct bank is included.
• Cathodic protection is included for underground piping.

4.4.4 Other
• EPCM work assumes that the selected site is void of all fatal-flaws which could
significantly impact project cost and schedule. These flaws include, but are not limited to:
habitat and locations of threatened-endangered and sensitive species, abundance of
other protected (e.g., native) species, distribution of noxious weeds, areas of critical
wildlife habitats and movement corridors, contaminated soil or hazardous materials,
archaeological artifacts, distribution and significance of cultural resources, Native
American Tribal concerns, recreational areas, special land use designations (e.g.,
Bureau of Land Management (BLM) Areas of Environmental Concern), and others.

4.5 Exclusions
As discussed above, the scope of the estimates is generally limited to scope within the project
fence. A list of items excluded from the estimate is as follows:

• Demolition and removal of existing structures

• Import duties & tariffs
• Extraordinary noise mitigation or attenuation
• Owner’s Costs
• Allowance for funds used during construction
• All taxes with the exception of payroll taxes
• All offsite infrastructure costs
• Upgrades to existing rail spur to accommodate delivery of large equipment
• Temporary housing and facilities for the construction workers

4.5.1.1. Typical Ow ner’s Costs

Owner’s costs are excluded from the estimate. Typical Owner’s costs include, but are not limited
to, the following:

• Permits & Licensing

• Land Acquisition / Rights of Way Costs
• Economic Development
• Project Development Costs (Geotechnical Investigation & Site Survey)
• Legal Fees
• Owner’s Engineering / Project & Construction Management Staff

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

• Plant Operators during start-up

• Electricity consumed during start-up
• Fuel and Reagent consumed during start-up (the salt melting fuel, propane, is included in
the O&M LCA information)
• Initial Fuel & Reagent Inventory (salt is included in the cost estimate and construction
LCA information)
• Transmission Interconnections & Upgrades
• Operating Spare Parts
• Financing Costs

4.6 Tow er Cost & Height Formula

Data and a formula for the cost of a concrete solar power tower as a function of tower height was
developed and can be found in Appendix H - Variable Tower Height Cost Information. NREL
provided three additional and separate sets of receiver and tower design data for a 50MW,
100MW, and 150MW (net) reference solar power plant. This data was used to design and
develop cost estimates for three additional towers used for the minimum, midpoint and maximum
height reference towers. The receiver design used for the base portion of this task was adjusted
for the different thermal duties, salt flow-rates, and receiver dimensions. The base salt piping
design was adjusted for flow-rate and tower height and the base cabling/conduit length was
adjusted for tower height. The weights of these adjusted systems were used to design the three
different towers and associated foundations. The total material and labor costs of the three
towers was calculated and a formula was developed as a function of the tower height as defined
in the NREL’s SAM model. The SAM model defines tower height as the distance from the
heliostat hinge point to the center of the receiver. For this analysis a fixed hinge point height of 7
meters above grade was used.

5. APPENDICES INFORMATION

Appendix A – Process Flow Diagram: The diagram illustrates the major flow paths of the plant
design. The Molten Salt is represented by the red lines, steam flows are blue, water flows are
black, and air flows are black. The only air flows on the diagram are the pressurization air to the
receiver inlet air vessel and the air removed from the top of the ACC by the steam jet air ejector.

Appendix B - Major Equipment List: This does not contain weights and is simply supplied for
information to show which equipment falls under each “subsystem”. The green hi-lighted areas are
the major categories as designated in SAM. The grey highlighted areas are the subsystems and the
un-highlighted areas are the major equipment items under its respective subsystem.

Appendix C – Capital Cost Estimate Summary: +/- 40% EPCM cost estimate broken down by the
NREL SAM major subsystems.

Appendix D – Water Usage: Plant annual water usage. A wet surface air cooler (WSAC) is utilized
for some of the auxiliary cooling heat rejection. This information is not included in Appendix “J”.

Appendix E – Specialized Equipment: The major specialized O&M equipment is provided in this
appendix. Both the heliostat wash water and wash truck fuel consumption is based on information
from Sandia as indicated. This information is not included in Appendix “I” or “J”.

Appendix F – O&M Energy: Energy amount and sources required by the plant other than the
electric and thermal energy obtained from solar insolation. This information is not included in
Appendix “J”.

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Appendix G – References: Non-confidential information available to the public. Numerous other

confidential sources, both internal and external to WorleyParsons, as well as national codes,
standards and specifications (e.g. ANSI, ASME, ASTM) were utilized in the development of this
Report.

Appendix H – Variable Tower Costs: The cost of a concrete power tower as a function of height, as
described in section 4.6, is provided in this appendix.

Appendix I – Total Mass of Plant Construction Summary: These tables provide the material
weights, and civil quantities, required to construct the plant, excluding the heliostat field (although
civil works are provided for the field – note foundations are categorized as structural by
WorleyParsons). Grading/earthwork quantities and rip-rap are excluded as the site is theoretical
and thus this information would necessarily be speculative. Both metric and U.S. customary unit
tables are provided. Note that last two columns are expressed volumetrically.

WorleyParsons used the following approach to account for the miscellaneous masses that
comprised less than 2% of the total mass of components, equipment, and parts:

• Most of the large equipment overall weights were inclusive of the items composing <2%
and the 2% item’s mass was assigned to the other more significant materials rather than
being excluded.

• Items included in systems generally comprised of commodities (e.g. piping, cable/wiring,

structural steel, foundations) generally excluded the weight of items that make up <2% of
the component’s mass. These 2% items include; gaskets, nuts/bolts, miscellaneous
supports (although weight of major pipe supports is included), ties/pins/clamps, portions
of grounding grid, portions of tubing, hose, some miscellaneous small bore pipe, some
pipe/conduit fittings, some mechanical specialty items (e.g. expansion joints, traps,
strainers), some miscellaneous valves, some miscellaneous instruments/wiring, lighting
fixtures, cathodic protection, weld filler, paint, primer, some galvanized coatings ,some
portions of handrail/grating/gates/ladders, signs, landscaping.

Appendix J – O&M Replacement Mass Summary: The O & M Replacement Mass Summary
provides the subsystem mass and general material type for the project over a 30 year lifetime,
excluding the heliostat field. The mass is expressed in pounds (lbm) with a summary conversion to
metric tonnes at the bottom of the table.
The derivation of the O&M replacement information relies on that generated for the parabolic
trough under previous Task 5, subtask 2 (WorleyParsons Project 59002505, Report NREL-0-LS-
019-0005 Rev 0), where relevant, and as such, many of the same references, vendor assistance
information and assumptions were utilized for consistency, including a 30 year plant lifetime.

O&M Consumables are provided as separate Appendices, external to Appendix J. These comprise
of Appendix D –Water Usage, Appendix E – Specialized Equipment and Appendix F – Other O&M
Energy Requirements.

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POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX A
Conceptual Process Flow Diagram
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX B
Major Equipment List
CLIENT: NREL of DOE
PROJECT: Power Tower Plant Cost & LCA
TITLE: Major Equipment List
REVISION: 0
DATE: 8/24/2012

Code ITEM QTY

01 SITE IMPROVEMENT
01A Site Improvement - Site Preparation
01B Site Improvement - Clearing & Grubbing
01C Site Improvement - Grading, Drainage, Remediation, Retention & Detention
01C Site Improvement - Evaporation Pond 1
01D Site Improvement - Roads, Parking, and Fences
01E Site Improvement - Water Supply Infrastructure
01E Well Water Forwarding Pumps 3x50%
01E Piping, Insulation Valves, and Fittings
02 HELIOSTAT FIELD (BY NREL)
02A Heliostat Field - Equipment
02A Heliostat Field - Mirrors 6,682
02A Heliostat Field - Drives 6,682
02A Heliostat Field - Foundations & Support Structures 6,682
02B Heliostat Field - Foundations & Support Structures
02B Heliostat Field - Foundations by NREL
02B Heliostat Field - Support Structures by NREL
02C Heliostat Field - Electrical
02C Heliostat Field Transformers by NREL
02C Heliostat Drive Power Converters by NREL
02C Power Supply Cable/Wiring by NREL
02D Heliostat Field - Instrumentation & Controls
02D Heliostat control sensors, software, and wiring by NREL
02 TOWER
02E Tower - Foundations & Support Structures
02E Tower Foundation 1
02E Tower Structure 1
02F Tower - Piping, Insulation, Valves, & Fittings
02G Tower - Equipment
02G Boom Crane 1
02H Tower - Electrical
02H Cable and Conduit
02I Tower - Instrumentation & Controls
02I Cable and Conduit
02 RECEIVER
02J Receiver - Equipment
02J Receiver Structure 1
02J Receiver Panels 20
02J Oven Boxes 40
02J Receiver Inlet Vessel 1
02J Receiver Outlet Vessel 1
02J Receiver Overflow Vessel 1
02J Receiver Air Compressor 1
02K Receiver - Pumps
02K Cold Salt Receiver Circulation Pumps 4x33%
02L Receiver - Piping, Insulation, Valves, & Fittings
02M Receiver - Electrical
02M Cable and Conduit
02N Receiver - Instrumentation & Controls
03 THERMAL ENERGY STORAGE SYSTEM (TES)
03G TES - Equipment
03G Cold Tank Immersion Heaters 4
03G Hot Tank Immersion Heaters 4
03G Internal Volume Air Heater System 1
03G Hot Tank Agitators 4
03H TES - Tanks
03H Cold Nitrate Salt Tank 1
03H Hot Nitrate Salt Tank 1
03I TES - Foundations & Support Structures
03J TES - Salt Media
03J Bulk Salt Storage 19,200 Tons
03K TES - Piping, Insulation, Valves, & Fittings
03L TES - Electrical
03M TES - Instrumentation & Controls
04 STEAM GENERATION SYSTEM (SGS)
04A SGS - Pumps
04A Steam Generator Evaporator Circulation Pump 2x100%
04A Steam Generator Preheater Circulation Pump 2x100%
04A SGS Hot Salt Circulation and Tank Transfer Pumps 3x50%
04A SGS Cold Salt Attemperation and Tank Transfer Pump 1 x 100%
04B SGS - Equipment & Heat Exchangers
04B Reheater 2 x 50%
04B Superheater 2 x 50%
04B Evaporator (Steam generator) 3 x 33%
04B Preheater (Economizer) 6 x 16%
04B Steam Drum 1x100%
04C SGS - Piping, Insulation, Valves, & Fittings
04D SGS - Electrical
04E SGS - Instrumentation & Controls
04F SGS - Foundations & Support Structures
05 FOSSIL BACKUP
N/A
06 ELECTRIC POWER GENERATION SYSTEM (EPGS)
06A Power Block - Steam Turbine Generator Island
06A Steam Turbine 1
CLIENT: NREL of DOE
PROJECT: Power Tower Plant Cost & LCA
TITLE: Major Equipment List
REVISION: 0
DATE: 8/24/2012

Code ITEM QTY

06A SITE IMPROVEMENT
Generator 1
06A Lube Oil and Hydraulic Oil System 1
06C Power Block - Blowdown System
06C Blowdown & Flash Tank Tank (Shop Fab) 1
06C Blowdown Piping, Insulation, Valves, & Fittings
06D Power Block - Cooling System
06D Air Cooled Condenser 1
06D Steam Air Ejector Skid (SJAE) 1
06E Power Block - Condensate System
06E Condensate - Piping, Insulation, Valves, & Fittings
06E Condensate Forwarding Pumps 3x50%
06E Condensate Storage Tank 1
06F Power Block - Boiler Feedwater System
06F Feedwater - Piping, Insulation, Valves, & Fittings
06F LP Feedwater Heater Drains- Piping, Insulation, Valves, & Fittings
06F HP Feedwater Heater Drains- Piping, Insulation, Valves, & Fittings
06F Feedwater Pumps 2x100%
06F Closed Feedwater Heaters 4
06F Feedwater Drain Pumps 2x100%
06F Deaerator/Storage Tank 1
06F Feedwater Heater (Start up) 1x100%
06G Power Block - Auxiliary Cooling / Closed Cooling Systems
06G Cooling Systems - Piping, Insulation, Valves, & Fittings
06G Wet Surface Air Cooler (WSAC) 1
06G Fin-Fan Cooler 1
06G Closed Cooling Water Pumps 2x100%
06G WSAC Blowdown Pumps (to evap ponds) 2x100%
06G WSAC Chemical Feed / Storage System 1 Lot
06G WSAC Makeup Water Tank 1
06G Closed Cooling Water Expansion Tank (Shop Fab) 1
06H Power Block - Steam Piping, Insulation Valves and Fittings
06H Main Steam - Piping, Insulation, Valves, & Fittings
06H Cold Reheat - Piping, Insulation, Valves, & Fittings
06H Hot Reheat - Piping, Insulation, Valves, & Fittings
06H Auxiliary, Extraction Steam, Vents & Drains - Piping, Insulation, Valves, & Fittings
06J Power Block - Water Treatment Systems
06J Service Water - Piping, Insulation, Valves, & Fittings
06J Service Water Pumps (from Raw/Fire water Tank) 2x100%
06J Demin Feed Pumps 2x100%
06J Demineralized Water Treatment System 1 Lot
06J Demin Forwarding Pumps (cycle makeup) 2x100%
06J Demin Startup/Cycle Make-up Pump 1x100%
06J Raw/Service/Fire Water Storage Tank (Field Erected) 1
06J Demineralized Water Storage Tank (Field Erected) 2
06J Potable Water Pumps 2x100%
06J Oil/Water Separator Effluent Forwarding Pumps 2x100%
06J Potable Water Storage Tank (Shop Fab) 1
06J Oil/Water Separator Tank 1
06J Water Sample Panel Skid 1
06J Sanitary/Industrial Waste Systems 1
06K Power Block - Power Distribution Systems
06K Generator Step-Up Transformer 1
06K Unit Auxilliary Transformer 2
06L Power Block - Backup Power Systems
06L Emergency Diesel Generator 3
06M Power Block - Instrumentation and Controls
06M Distributed Control System 1
06N Power Block - Fire Protection System
06N Fire Protection - Piping, Insulation, Valves, & Fittings
06N Firewater Forwarding Pump (Electric Driven) 1x100%
06N Firewater Jockey Pump (Pressure Maintenance) 1x100%
06N Emergency Diesel-Driven Firewater Pump 1x100%
06O Power Block - Foundations & Support Structures
06P Power Block - Buildings
06Q Power Block - BOP Mechanical Systems
06Q BOP - Piping, Insulation, Valves, & Fittings
06Q Electric Auxiliary Boiler 1
06Q Instrument/Service Air Compressors 2x100%
06Q Diesel Fuel Tank & Pump System (On-site Maintenance Trucks) 1
06Q Turbine Area Flash Tank (Shop Fab) 1
06R Power Block - BOP Electrical Systems
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX C
Power Tower Plant Capital Cost Summary:
Materials and Labor
 ESTIMATE SUMMARY
(Using Arizona merit shop labor rates)
NREL Task 8 Solar Power Tower Cost Assessment
100 MW net with Thermal Storage - Dry Cooled
10/8/2012
Revision 2 - RCP

ITEM QTY UNIT MATERIAL LABOR TOTAL COMMENTS

01 Site Improvements 1 LS $ 6,849,000 $ 12,480,000 $ 19,329,000

02 Tower / Receiver Components 1 LS $ 45,931,000 $ 25,577,000 $ 71,508,000
03 Thermal Energy Storage System 1 LS $ 50,495,000 $ 5,745,000 $ 56,240,000
04 Steam Generation System 1 LS $ 31,001,000 $ 10,944,000 $ 41,945,000
05 Fossil Backup 1 LS $ - $ - $ -
06 Electric Power Generation System 1 LS $ 87,244,000 $ 27,747,000 $ 114,991,000
07 EPCM Costs 1 LS $ 29,001,000 Professional services
08 Project, Land, Misc. 1 LS $ - Excluded
09 %DC's Sales Tax Applies 1 LS $ - Excluded
Subtotal $ 221,520,000 $ 82,493,000 $ 333,014,000

Contingency $ 31,680,000

TOTAL ESTIMATE - EPCM BASIS $ 364,694,000

CRITICAL NOTES
Labor rates are merit shop-based for Arizona with a productivity factor of 1.0

SAM User 1-Adjusted

POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX D
Water Usage
 Water Usage
Annual Water Consumption Annual Water Consumption
Item Description
(Acre-Feet / Year) (Cubic Meters / Year)
Heliostat Water Wash 45 56,000
Steam Cycle & Balance of Plant (BOP) 55 68,000
Total 100 124,000

Assumptions/Notes:
1. Water Consumption calculation includes water treatment equipment efficiency losses; no waste water treatment system
assumed.
2. Heliostat water wash consumption estimated from Sandia Report SAND2007-3293, Appendix "A", from Scott Jones'
Memo; "Estimating the Present Value of Collector Washing Costs at a Solar Plant" using a blend of Solar Two and
Kramer Junction Company (KJC) data.
3. Water consumption excludes possible periodic dust suppression/palliative applications.
4. Water treatment chemical usage is minor and is roughly estimated at 5,000 lb/yr (2,300 kg/yr).
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX E
Specialized Equipment List
 Specialized Equipment
Fuel Economy Annual mileage Annual Fuel Annual Fuel
Item description Quantity Fuel Type
(mpg) (per truck) Consumption (gal/yr) Consumption (liters/yr)

Heliostat Water Wash Trucks 14 Diesel 31,300 118,000

General Maintenance: 3/4 Ton truck (note 2) 4 15 Gasoline 800 213 810

Assumptions/Notes:
1. Heliostat water wash truck annual fuel consumption estimated from Sandia Report SAND2007-3293, Appendix "A", from Scott Jones' Memo; "Estimating the
Present Value of Collector Washing Costs at a Solar Plant" using a blend of Solar Two and Kramer Junction Company (KJC) fuel usage data.
2. General maintenance vehicles are estimated here based on conventional plant site experience. These general maintenance vehicles can be specified to meet
most plant needs.
3. Use of all other O & M vehicles such as man lifts, scissor lifts, and forklifts is considered infrequent and fuel consumption considered negligible compared to the
Wash and General Maintenance vehicles fuel consumption.
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX F
Other O&M Energy Requirements
 Other O & M Energy Requirements
Item Source Quantity

Auxiliary Electricity Grid 17,600 MW-hr/year

Propane (Initial 1st year salt melting only) Portable/temporary 124,000 Gallon
Natural gas N/A 0 MMBtu/year

Assumptions/Notes:
1. Auxiliary electricity is off-line power consumption backfed from the grid; the bulk of the
consumption is utilized in the heating of various salt systems.
2. Natural gas use is N/A due to assumed implementation of an electric auxiliary boiler.
3. Diesel fuel required for any Specialized Equipment is excluded here.
4. Portable propane trailer(s) were assumed for initial salt melting.
5. Nitrogen usage for the Steam Generation System and any other steam systems layup is minor.
6. MMBtu = Million Btu
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX G
References
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

The below references represent non-confidential information available to the public. Numerous other
confidential sources, both internal and external to WorleyParsons, as well as national codes, standards
and specifications (e.g. ANSI, ASME, ASTM) were utilized in the development of this Report.
1. Kelly, B. and Kearney, D., “Thermal Storage Commercial Plant Design Study for a 2-Tank Indirect Molten
Salt System,” NREL/SR-550-40166, July 2006.
2. Litwin, R.Z., “Receiver System: Lessons Learned from Solar Two,” SAND2002-0084, March 2002.
3. Reilly, H.E., and G.J. Kolb, “An Evaluation of Molten-Salt Power Towers Including Results of the Solar
Two Project,” SAND2001-3674, November 2001.
4. Zavoico, A.B., “Solar Power Tower Design Basis Document,” SAND2001-2100, July 2001.
5. Turchi, Craig, NREL. “NREL Power Tower for WP Task 8 study SAM-2011-12-02.zsam.” SAM model
file sent to Ryan Bowers. February 15, 2012. E-mail.
6. Kolb, G.J. et al., “Heliostat Cost Reduction Study”, SAND2007-3293, June 2007.
7. WorleyParsons, “CSP Parabolic Trough Plant Cost Assessment,” Technical report and supplemental
documents, WorleyParsons Group, Denver, Report No. 59002501-NREL-0-LS-019-0001, Sept 2009.
8. WorleyParsons, “Material Input for Life Cycle Assessment,” Technical report and supplemental
documents, WorleyParsons Group, Denver, Report No. 59002505-NREL-0-LS-019-0005, Jan 2010.
9. All City Fence Co. Chain Link Fabric. (2011). Retrieved from
http://www.allcityfence.com/material/chain_link.html
10. Aluminum Roll Jacketing. (2008). Retrieved from http://idealproducts.ca/pdf/alumpaint.pdf
11. ASC Steel Floor Deck. (2012). Retrieved from http://www.ascsd.com/files/FloorDeck.pdf
12. Bonney Forge® Cast Steel Valves. (2012). Retrieved from http://bonneyforge.com/resources/CSV.pdf
13. Bonney Forge® Class 800/1500 lb Gate Valves-Bolted Bonnet-Full & Reduced Port. (2012). Retrieved
from http://bonneyforge.com/specs/forged/800_1500lb_GateValve.pdf
14. CALICO Industrial Fixed Cage Ladders. (2012). Retrieved from
http://www.calicoladders.com/fixed_ladders.html
15. CAVCO Pipe Valves & Fittings HDPE Pipe Sizes. (2012). Retrieved from
http://cavcovalve.com/Resources_files/hdpe%20pipe%20chart%201%20.pdf
16. Chromalox® Mineral Insulated Cable. (2012). Retrieved from
http://www.chromalox.com/catalog/resources/MOD-MI.pdf
17. Crane® Cast Steel Valves – Technical Datasheet. (2012). Retrieved from
http://www.craneenergy.com/energy/products/multi-turn-valves/cast-steel-valves/crane-cast-steel-valves
18. DOWFROST HD Propylene Glycol-based Heat Transfer Fluid. (2012). Retrieved from
http://www.dow.com/heattrans/products/glycol/dowfrost.htm
19. Fiberglass Technical Data. (n.d.). Retrieved from http://thermostatic.com/techdata/fiberglassdata.shtml
20. FILMTEC™ Membranes – Element Weight. (July 2012). Retrieved from https://dow-
answer.custhelp.com/app/answers/detail/a_id/213/kw/FILMTEC
21. FILMTEC™ Membranes, FILMTEC BW30-365-FR Fouling Resistant RO Element, Form No. 609-
00368-1008. (2011). Retrieved from
http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0613/0901b80380613ea6.pdf?filepath=li
quidseps/pdfs/noreg/609-00368.pdf&fromPage=GetDoc
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

22. Flowserve® Edward Forged Steel Valves. (2012). Retrieved from

http://flowserve.com/files/Files/Literature/ProductLiterature/FlowControl/Edward/EVENCT0001.pdf
23. General Cable Industrial Cable Catalog. (January 2010). Retrieved from
http://www.generalcable.com/GeneralCable/en-US/Products/IndustrialCables/Catalog
24. General Cable Fiber Optic Cable Catalog. (December 2010). Retrieved from
http://www.generalcable.com/GeneralCable/en-US/Products/FiberOpticCables
25. GEOTEX® 2130 Polypropylene fabric. (2012). Retrieved from
http://geotextile.com/downloads/Geotex%202130%20Product%20Data%20Sheet.pdf
26. GEOTEX® 2x2HF Polypropylene fabric. (2012). Retrieved from
http://geotextile.com/downloads/Geotex%202x2HF%20Product%20Data%20Sheet.pdf
27. Grating Pacific Welded Steel Bar Grating. (2012). Retrieved from
http://www.gratingpacific.com/load_tables/catalogs/metal-bar-grating.pdf
28. Industrial Insulation Group, LLC Thermo-12 Gold Pipe & Block Insulation. (November 2008). Retrieved
from http://www.spi-co.com/paragonpacific/images/IIG300.pdf
29. Industrial Insulation Group, LLC MinWool-1200 Pipe and Tank Wrap. (2012). Retrieved from
http://www.iig-llc.com/pdfs/IIG-415-Mineral-Wool-1200-Pipe-and-Tank-Wrap.pdf
30. Newco - Cast Steel Bolted Bonnet Valve. (2012). Retrieved from
http://www.superiorvalves.com/pdf/NEWCO_CastSteelBoltedBonnet_GGCA_Catalog.pdf
31. Nexans Instrumentation Cable. (2012). Retrieved from
http://www.nexans.com.mx/eservice/CentralAmerica-
es_MX/fileLibrary/Download_540152129/CentralAmerica/files/Instrumentation_2.pdf
32. Reinforced Concrete Pipe. (March 15, 2006). Retrieved from
http://www.hansonpipeandprecast.com/tech_specs/VA/02.05_12_36_B_Wall.pdf
33. ROXUL® Mineral Fiber Block and Board Thermal Insulation. (March 2010). Retrieved from
http://www.roxul.com/files/RX-NA-EN/pdf/RHT80-3-30-10.pdf
34. Southwire Bare Copper Wire and Cable. (1998). Retrieved from
http://www.southwire.com/products/ProductCatalog.htm
35. TENAX GNT 1300 Geonets Mesh Drainage Media. (2012). Retrieved from
http://www.tenax.net/pdf_geo_e/gnt1300_e.pdf
36. Tioga Pipe Chart. (2012). Retrieved from http://www.tiogapipe.com/TiogaChart.pdf
37. USA Wire & Cable, INC. 20-10 Control Cable. (n.d.). Retrieved from http://www.usawire-
cable.com/pdfs/20_10%2014-10AWG.pdf
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX H
Tower Height Cost Information
CLIENT NREL of DOE
PROJECT Power Tower Plant Cost & LCA
TITLE Variable Tower Cost
ORIGINATOR Bob Pieksma
REVIEWER Ryan Bowers
REVISION A
DATE 6/19/2012

Tower Height, Meters (SAM Definition) 122 178 217

Total Material $11,005,236 $18,986,234 $28,186,228
Total Labor $9,600,323 $16,450,185 $24,380,024
Total Cost $20,605,559 $35,436,419 $52,566,252

Tower Costs vs. Height
$60,000,000

$50,000,000

y = 1835.7x2 ‐ 285868x + 3E+07

$40,000,000

$30,000,000

$20,000,000

$10,000,000

$0
100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250
Tower Height, meters (SAM definition)
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX I
Total Mass of Plant Construction Summary
CLIENT NREL of DOE
PROJECT Power Tower Plant Cost & LCA Input
TITLE Plant Capital Cost LCA Data - METRIC
REVISION 1
DATE 10/8/2012

Carbon Steel, Stainless Oils, Crushed

Alloy Steel Copper Aluminum Insulation Plastics Salt Concrete Asphalt
ITEM Iron & Zinc Steel Lubricants Stone/ Gravel
[Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Cubic Meters] [Cubic Meters]

SITE IMPROVEMENT TOTALS 103 3 1 1 0 0 399 0 0 624 3,876 46,609

HELIOSTAT FIELD TOTALS (BY NREL)
TOWER TOTALS 2,811 97 5 2 2 40 1 0 0 53,033 0 0
RECEIVER TOTALS 384 137 70 40 4 88 14 0 0 0 0 0
THERMAL ENERGY TOTALS 524 452 2 10 17 1,069 3 0 17,418 2,879 0 0
STEAM GENERATION SYSTEM TOTALS 2,794 254 8 68 7 27 15 0 0 10,080 0 0
ELECTRIC POWER GENERATION TOTALS 4,907 67 249 185 257 53 115 95 0 12,213 0 280

SOLAR POWER TOWER PLANT TOTALS 11,524 1,011 335 306 287 1,276 545 95 17,418 78,828 3,876 46,889
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX J
O&M Replacement Mass Summary
 OPERATIONS & MAINTENANCE SCHEDULE
Assumed Plant Life [yr.] 30
Client: NREL of DOE
Project: Power Tower Plant Cost & LCA Input
Title: O&M Schedule
Date: 9/4/2012
Rev: 0

Replacement Materials / Weights (lb)

Graphite
Lifetime Repl Carbon Stainless
Major Subsystem Alloy Packing / Copper Salt FRP Oil Other
Weight (lb) Steel Steel
Gasket

SITE IMPROVEMENTS 4,159 1,224 290 0 29 2,573 0 0 0 44

HELIOSTAT FIELD-BY NREL
TOWER / RECEIVER 203,739 26,593 4,386 98,161 39,734 33,674 0 0 0 1,191
THERMAL ENERGY STORAGE SYSTEM 1,126,692 2,057 1,804 6,754 0 708 1,113,600 0 0 1,769
STEAM GENERATION SYSTEM 143,698 15,592 93,000 1,283 8,995 24,001 0 0 0 827
ELECTRIC POWER GENERATION SYSTEM - POWER BLOCK 493,999 80,092 25,765 9,773 157 29,168 0 34,000 303,512 11,519

TOTALS (LB) 1,972,288 125,557 125,245 115,970 48,915 90,124 1,113,600 34,000 303,512 15,350

TOTALS (Metric Tonnes) 894.6 57.0 56.8 52.6 22.2 40.9 505.1 15.4 137.7 7.0

Major Assumptions & Clarifications

1. Air Cooled Condenser (ACC) tube bundles do not need replacement.

2. Refer to Water Usage, Specialized Equipment, and Other O&M Energy for consumables.
3. Salt replacement occurs at a rate of 0.1% per year.
4. Building and grounds maintenance is excluded, e.g. roof replacements, road resurfacing, etc.