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.

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

Technical Report

NREL/TP-5500-57625

February 2013
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

15013 Denver West Parkway

Golden, Colorado 80401

303-275-3000 • www.nrel.gov

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

Technical Report

NREL/TP-5500-57625

February 2013
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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
1 

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-MWe (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 
2 

circa 42%. The current state-of-the-art is embodied in the 19.9-MWe Gemasolar Tower that was 

commissioned in Spain in 2011 [6]. In the US, the 110 MWe 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-ofthe-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). 
3 

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 
4 

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 
5 

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. 
6 

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 

Roadmap [8] 

WorleyParsons 

Group

(Appendix)

SAM 

2012-11-30 

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 

(Steam Generation

System)

$/kW 350 365 350

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 

above

9.5 7

Indirect Cost Category

EPC & Owner Costs % of DC 25 - 11

Land $/acre - - 10,000

Sales Tax Rate applied to 

80% of DC

7.75%

(CA)

- 5.0%

(US avg)

Financing during 

Construction

% of overnight 

costs

- - 6.0

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. 
7 

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-MWe 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: 
8 

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.
9 

Table 2. SAM modeling results using the spreadsheet cost model.

Design Parameters

SAM

2012-11-30 

Default 

Case

SAM

2012-11-30

Spreadsheet

Model

Arizona 

Labor Rates 

Case

Smaller 

Tower Case

Power block gross rating (MWe) 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 

(°C)

42 42 42 42

Location (weatherfile) Daggett, CA Daggett, CA Tucson, AZ Daggett, CA

Size Parameters

Tower height (m) 203 203 203 93

Receiver design thermal power (MWt) 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 (MWe), annual average 105 105 105 18

Annual net electricity generation (MWh) 539,700 539,700 519,400 109,200

Capacity factor (based on MWe 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 ($/kWe, net) 7,490 7,500 6,870 11,000

Total Project Installed Costs ($/kWe, 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-MWe (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 differentsize 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. 
10 

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. 
11 

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 
12 

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
13 

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

User Variable 5 i45

Annual O&M variable cost, used to calc 

Variable Cost by Generation

Fossil Fuel Cost i46

User Variable 6 i47 Estimated O&M labor force
14 

Appendix C – Financial Assumptions Used for SAM 

Power Tower Reference Plants
15 

Appendix D – WorleyParsons Subcontract Report:

Power Tower Plant Cost and Material Input to Life 

Cycle Assessment (LCA)
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

PROJECT 108037-03981

REV DESCRIPTION ORIG REVIEW WORLEYPARSONS

APPROVAL

DATE CLIENT

APPROVAL

DATE

0 FINAL Issue-PUBLIC JLS

J.Straubinger

RDB

R. Bowers

RCP

R. Pieksma

9 -6-12

1 Revision of Appendices JLS

J.Straubinger

RDB

R. Bowers

RCP

R. Pieksma

9-11-12 

2 Revision of Construction 

Weights

JLS

J. Straubinger

RDB

R. Bowers

RCP

R. Pieksma

10-08-12 

 

 

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 

based on this document, is the responsibility of the alternative user or 

third party.

No part of this publication may be reproduced, stored in a retrieval 

system or transmitted, in any form or by any means, electronic, 

mechanical, photocopying, recording or otherwise, without the prior 

permission of WorleyParsons.

Any questions concerning the information or its interpretation should be 

directed to Robert Pieksma, Project Engineer.
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-3

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
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-4

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)
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-5

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
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-6

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. 
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-7

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.
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-8

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 Rates

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 manhours 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 Productivity

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 Availability

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
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-9

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

4.4 Clarifications

4.4.1 Civil / 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.
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-10

4.4.3 Electrical / Instrumentation

• 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 Owner’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
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-11

• 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 Tower 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”. 
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

Page-12

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-LS019-0005 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. 
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 QTY

01

01A

01B

01C

01C 1

01D

01E

01E 3x50%

01E

02

02A

02A 6,682

02A 6,682

02A 6,682

02B

02B by NREL

02B by NREL

02C

02C by NREL

02C by NREL

02C by NREL

02D

02D by NREL

02

02E

02E 1

02E 1

02F

02G

02G 1

02H

02H

02I

02I

02

02J

02J 1

02J 20

02J 40

02J 1

02J 1

02J 1

02J 1

02K

02K 4x33%

02L

02M

02M

02N

03

03G

03G 4

03G 4

03G 1

03G 4

03H

03H 1

03H 1

03I

03J

03J 19,200 Tons

03K

03L

03M

04

04A

04A 2x100%

04A 2x100%

04A 3x50%

04A 1 x 100%

04B

04B 2 x 50%

04B 2 x 50%

04B 3 x 33%

04B 6 x 16%

04B 1x100%

04C

04D

04E

04F

05

06

06A

06A 1

Receiver - Instrumentation & Controls

SGS - Instrumentation & Controls

SGS - Foundations & Support Structures

SGS - Equipment & Heat Exchangers

Power Block - Steam Turbine Generator Island

Preheater (Economizer)

Steam Drum

SGS - Piping, Insulation, Valves, & Fittings

Evaporator (Steam generator)

TES - Equipment

TES - Tanks

TES - Foundations & Support Structures

TES - Salt Media

SGS - Pumps

Internal Volume Air Heater System

Cold Tank Immersion Heaters

Hot Tank Immersion Heaters

TES - Instrumentation & Controls

Receiver - Equipment

Receiver - Pumps

Tower Structure

Cable and Conduit

Receiver Structure

Receiver Panels

Site Improvement - Grading, Drainage, Remediation, Retention & Detention

Heliostat Field - Mirrors

Tower - Foundations & Support Structures

Tower - Equipment

Tower - Electrical

Tower - Instrumentation & Controls

Site Improvement - Site Preparation

Site Improvement - Clearing & Grubbing

Heliostat Field - Equipment

Heliostat Field - Foundations & Support Structures

Heliostat Field - Electrical

Heliostat Field - Instrumentation & Controls

Site Improvement - Roads, Parking, and Fences

Site Improvement - Water Supply Infrastructure

Steam Generator Preheater Circulation Pump

Bulk Salt Storage

TES - Piping, Insulation, Valves, & Fittings

TES - Electrical

SGS - Electrical

FOSSIL BACKUP

SGS Hot Salt Circulation and Tank Transfer Pumps

SGS Cold Salt Attemperation and Tank Transfer Pump

Reheater

Superheater

Heliostat Field - Drives

Heliostat Field - Foundations & Support Structures

Heliostat Field Transformers

Heliostat Drive Power Converters

Power Supply Cable/Wiring

STEAM GENERATION SYSTEM (SGS)

Hot Tank Agitators

Cold Nitrate Salt Tank

Tower Foundation

Site Improvement - Evaporation Pond

Well Water Forwarding Pumps

Piping, Insulation Valves, and Fittings

Steam Turbine

Tower - Piping, Insulation, Valves, & Fittings

Boom Crane

THERMAL ENERGY STORAGE SYSTEM (TES)

ITEM

SITE IMPROVEMENT

HELIOSTAT FIELD (BY NREL)

TOWER

RECEIVER

Hot Nitrate Salt Tank

Heliostat control sensors, software, and wiring

Heliostat Field - Foundations

Heliostat Field - Support Structures

Cable and Conduit

Oven Boxes

Receiver Inlet Vessel

Receiver Outlet Vessel

Receiver Overflow Vessel

Receiver Air Compressor

Cold Salt Receiver Circulation Pumps

Receiver - Piping, Insulation, Valves, & Fittings

Cable and Conduit

Receiver - Electrical

ELECTRIC POWER GENERATION SYSTEM (EPGS)

N/A

Steam Generator Evaporator Circulation Pump
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 1

06A 1

06C

06C 1

06C

06D

06D 1

06D 1

06E

06E

06E 3x50%

06E 1

06F

06F

06F

06F

06F 2x100%

06F 4

06F 2x100%

06F 1

06F 1x100%

06G

06G

06G 1

06G 1

06G 2x100%

06G 2x100%

06G 1 Lot

06G 1

06G 1

06H

06H

06H

06H

06H

06J

06J

06J 2x100%

06J 2x100%

06J 1 Lot

06J 2x100%

06J 1x100%

06J 1

06J 2

06J 2x100%

06J 2x100%

06J 1

06J 1

06J 1

06J 1

06K

06K 1

06K 2

06L

06L 3

06M

06M 1

06N

06N

06N 1x100%

06N 1x100%

06N 1x100%

06O

06P

06Q

06Q

06Q 1

06Q 2x100%

06Q 1

06Q 1

06R

Power Block - Foundations & Support Structures

Power Block - Buildings

Power Block - BOP Mechanical Systems

Power Block - Auxiliary Cooling / Closed Cooling Systems

Power Block - Steam Piping, Insulation Valves and Fittings

Power Block - Water Treatment Systems

Power Block - Power Distribution Systems

Power Block - Blowdown System

Power Block - Cooling System

Lube Oil and Hydraulic Oil System

Auxiliary, Extraction Steam, Vents & Drains - Piping, Insulation, Valves, & Fittings

Demin Startup/Cycle Make-up Pump

Power Block - Fire Protection System

Power Block - Backup Power Systems

Power Block - Instrumentation and Controls

Steam Air Ejector Skid (SJAE)

Turbine Area Flash Tank (Shop Fab)

Distributed Control System

Firewater Forwarding Pump (Electric Driven)

Firewater Jockey Pump (Pressure Maintenance)

Emergency Diesel-Driven Firewater Pump

Electric Auxiliary Boiler

Instrument/Service Air Compressors

Diesel Fuel Tank & Pump System (On-site Maintenance Trucks)

Power Block - BOP Electrical Systems

Raw/Service/Fire Water Storage Tank (Field Erected)

Emergency Diesel Generator

Air Cooled Condenser

Condensate - Piping, Insulation, Valves, & Fittings

Condensate Forwarding Pumps

Condensate Storage Tank

Power Block - Condensate System

Power Block - Boiler Feedwater System

Cooling Systems - Piping, Insulation, Valves, & Fittings

Wet Surface Air Cooler (WSAC)

Fire Protection - Piping, Insulation, Valves, & Fittings

Blowdown & Flash Tank Tank (Shop Fab)

Blowdown Piping, Insulation, Valves, & Fittings

Feedwater - Piping, Insulation, Valves, & Fittings

LP Feedwater Heater Drains- Piping, Insulation, Valves, & Fittings

HP Feedwater Heater Drains- Piping, Insulation, Valves, & Fittings

Feedwater Pumps

Closed Feedwater Heaters

Feedwater Drain Pumps

Deaerator/Storage Tank

Feedwater Heater (Start up)

Main Steam - Piping, Insulation, Valves, & Fittings

Cold Reheat - Piping, Insulation, Valves, & Fittings

Hot Reheat - Piping, Insulation, Valves, & Fittings

Demineralized Water Treatment System

Service Water Pumps (from Raw/Fire water Tank)

Demin Feed Pumps

Sanitary/Industrial Waste Systems

BOP - Piping, Insulation, Valves, & Fittings

WSAC Blowdown Pumps (to evap ponds)

WSAC Chemical Feed / Storage System

Generator

Potable Water Pumps

Demin Forwarding Pumps (cycle makeup)

Fin-Fan Cooler

Closed Cooling Water Pumps

WSAC Makeup Water Tank

Closed Cooling Water Expansion Tank (Shop Fab)

Generator Step-Up Transformer

Unit Auxilliary Transformer

Demineralized Water Storage Tank (Field Erected)

Oil/Water Separator Effluent Forwarding Pumps

Potable Water Storage Tank (Shop Fab)

Oil/Water Separator Tank

Water Sample Panel Skid

Service Water - Piping, Insulation, Valves, & Fittings
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX C 

Power Tower Plant Capital Cost Summary: 

Materials and Labor
SAM User 1-Adjusted

10/8/2012Revision 2 - RCPITEM QTY UNIT MATERIAL LABOR 

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

$

02 Tower / Receiver Components 1 LS 45,931,000 $ 25,577,000 $ 

$

03 Thermal Energy Storage System 1 LS 50,495,000 $ 5,745,000 $ 

$

04 Steam Generation System 1 LS 31,001,000 $ 10,944,000 $ 

$

05 Fossil Backup 1 LS - $ - $ 

$

06 Electric Power Generation System 1 LS 87,244,000 $ 27,747,000 $ 

$

07 EPCM Costs 1 LS 

$ 

08 Project, Land, Misc. 1 LS 

$ 

09 %DC's Sales Tax Applies 1 LS 

$ 

Subtotal 221,520,000 $ 82,493,000 $ 3

$

Contingency $ 

TOTAL ESTIMATE - EPCM BASIS 3

$

CRITICAL NOTES

ESTIMATE SUMMARY

(Using Arizona merit shop labor rates)

NREL Task 8 Solar Power Tower Cost Assessment

100 MW net with Thermal Storage - Dry Cooled

Labor rates are merit shop-based for Arizona with a productivity factor of 1.0
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX D 

Water Usage
45 56,000

55 68,000

100 124,000

Assumptions/Notes:

1.

2.

3.

4.

Water Consumption calculation includes water treatment equipment efficiency losses; no waste water treatment system

assumed.

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.

Water consumption excludes possible periodic dust suppression/palliative applications.

Water treatment chemical usage is minor and is roughly estimated at 5,000 lb/yr (2,300 kg/yr).

Water Usage

Item Description

Heliostat Water Wash

Steam Cycle & Balance of Plant (BOP)

Total

Annual Water Consumption

(Acre-Feet / Year)

Annual Water Consumption

(Cubic Meters / Year)
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX E 

Specialized Equipment List
14 Diesel 31,300 118,000

4 15 Gasoline 800 213 810

Assumptions/Notes:

1.

2.

3.

Specialized Equipment

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.

General maintenance vehicles are estimated here based on conventional plant site experience. These general maintenance vehicles can be specified to meet

most plant needs.

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.

Item description

Heliostat Water Wash Trucks

General Maintenance: 3/4 Ton truck (note 2)

Annual Fuel

Consumption (gal/yr) Quantity Fuel Economy(mpg) Fuel Type Annual mileage(per truck)

Annual Fuel

Consumption (liters/yr)
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX F 

Other O&M Energy Requirements
Source

Grid 17,600 MW-hr/year

Portable/temporary 124,000 Gallon

N/A 0 MMBtu/year

Assumptions/Notes:

1.

2.

3.

4.

5.

6. MMBtu = Million Btu

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.

Nitrogen usage for the Steam Generation System and any other steam systems layup is minor.

Portable propane trailer(s) were assumed for initial salt melting.

Diesel fuel required for any Specialized Equipment is excluded here.

Natural gas use is N/A due to assumed implementation of an electric auxiliary boiler.

Natural gas

Quantity

Other O & M Energy Requirements

Item

Auxiliary Electricity

Propane (Initial 1st year salt melting only)
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. FILMTECTM Membranes – Element Weight. (July 2012). Retrieved from https://dowanswer.custhelp.com/app/answers/detail/a_id/213/kw/FILMTEC 

21. FILMTECTM 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/CentralAmericaes_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.usawirecable.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

y = 1835.7x2 ‐ 285868x + 3E+07

$50,000,000

$60,000,000

Tower Costs vs. Height

y = 1835.7x2 ‐ 285868x + 3E+07

$0

$10,000,000

$20,000,000

$30,000,000

$40,000,000

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 InputTITLE Plant Capital Cost LCA Data - METRICREVISION 1DATE 10/8/2012

Carbon Steel, Iron & Zinc

Stainless Steel Alloy Steel Copper Aluminum Insulation Plastics Oils, Lubricants Salt Concrete 

[Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Tonnes] [Metric Ton

SITE IMPROVEMENT TOTALS 103 3 1 1 0 0 399 0 0 

HELIOSTAT FIELD TOTALS (BY NREL)TOWER TOTALS 2,811 97 5 2 2 40 1 0 0 53

RECEIVER TOTALS 384 137 70 40 4 88 14 0 0 

THERMAL ENERGY TOTALS 524 452 2 10 17 1,069 3 0 17,418 2

STEAM GENERATION SYSTEM TOTALS 2,794 254 8 68 7 27 15 0 0 10

ELECTRIC POWER GENERATION TOTALS 4,907 67 249 185 257 53 115 95 0 12

SOLAR POWER TOWER PLANT TOTALS 11,524 1,011 335 306 287 1,276 545 95 17,418 78

ITEM
POWER TOWER PLANT COST AND MATERIAL INPUT TO LCA

APPENDIX J 

O&M Replacement Mass Summary 
30

Client: NREL of DOE

Project: Power Tower Plant Cost & LCA Input

Title: O&M Schedule

Date: 9/4/2012

Rev: 0

Lifetime Repl

Weight (lb)

Carbon

Steel

Stainless

Steel Alloy

Graphite

Packing /

Gasket

Copper Salt FRP Oil Other

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

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

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

894.6 57.0 56.8 52.6 22.2 40.9 505.1 15.4 137.7 7.0

Replacement Materials / Weights (lb)

ELECTRIC POWER GENERATION SYSTEM - POWER BLOCK

TOTALS (Metric Tonnes)

Assumed Plant Life [yr.]

OPERATIONS & MAINTENANCE SCHEDULE

Major Subsystem

SITE IMPROVEMENTS

HELIOSTAT FIELD-BY NREL

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.

TOTALS (Metric Tonnes)