National Renewable Energy Laboratory 

Innovation for Our Energy Future 

A national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

NREL is operated by Midwest Research Institute ● Battelle Contract No. DE-AC36-99-GO10337 

Economic, Energy, and 

Environmental Benefits of 

Concentrating Solar Power in 

California 

L. Stoddard, J. Abiecunas, and R. O'Connell 

Black & Veatch 

Overland Park, Kansas 

In Collaboration with the Interfaith Environmental Council and the 

Coalition on the Environment and Jewish Life of Southern California

Los Angeles, California 

Subcontract Report 

NREL/SR-550-39291 

April 2006 
Economic, Energy, and 

Environmental Benefits of 

Concentrating Solar Power in 

California 

May 2005 – April 2006 

L. Stoddard, J. Abiecunas, and R. O'Connell 

Black & Veatch 

Overland Park, Kansas 

NREL Technical Monitor: M. Mehos 

Prepared under Subcontract No. AEK-5-55036-01

Reviewed by: 

Tim Carmichael, Coalition for Clean Air 

Los Angeles, California 

Ralph Cavanagh, Natural Resources Defense Council 

San Francisco, California 

Mary Nichols, UCLA Institute of the Environment 

Los Angeles, California 

Lee Wallach, Coalition on the Environment and Jewish 

Life and Interfaith Environmental Council 

Ryan Wiser, Lawrence Berkeley National Laboratory 

Berkeley, California

Subcontract Report 

NREL/SR-550-39291 

April 2006 

National Renewable Energy Laboratory 

1617 Cole Boulevard, Golden, Colorado 80401-3393 

303-275-3000 • www.nrel.gov 

Operated for the U.S. Department of Energy 

Office of Energy Efficiency and Renewable Energy 

by Midwest Research Institute • Battelle 

Contract No. DE-AC36-99-GO10337
NOTICE

This report was prepared as an account of work sponsored by an agency of the United States government. 

Neither the United States government nor any agency thereof, nor any of their employees, makes any 

warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or 

usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not 

infringe privately owned rights. Reference herein to any specific commercial product, process, or service by 

trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, 

recommendation, or favoring by the United States government or any agency thereof. The views and 

opinions of authors expressed herein do not necessarily state or reflect those of the United States 

government or any agency thereof. 

Available electronically at http://www.osti.gov/bridge

Available for a processing fee to U.S. Department of Energy 

and its contractors, in paper, from: 

U.S. Department of Energy 

Office of Scientific and Technical Information 

P.O. Box 62 

Oak Ridge, TN 37831-0062 

phone: 865.576.8401 

fax: 865.576.5728 

email: mailto:reports@adonis.osti.gov

Available for sale to the public, in paper, from: 

U.S. Department of Commerce 

National Technical Information Service 

5285 Port Royal Road 

Springfield, VA 22161 

phone: 800.553.6847 

fax: 703.605.6900 

email: orders@ntis.fedworld.gov

online ordering: http://www.ntis.gov/ordering.htm

This publication received minimal editorial review at NREL 

Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste 
NREL CA Solar Benefits Contents 

Contents 

Executive Summary.......................................................................................................ES-1 

1.0 Introduction.......................................................................................................... 1-1 

2.0 CSP Technology Assessment .............................................................................. 2-1 

2.1 Description of Technologies.................................................................... 2-2 

2.2 Commercial Status of Technologies ........................................................ 2-3 

2.3 Technology Selection for Benefits Analysis............................................ 2-4 

3.0 California CSP Resource Assessment ................................................................. 3-1 

4.0 Deployment of CSP Plants in California ............................................................. 4-1 

5.0 Economic Impacts of CSP in California.............................................................. 5-1 

5.1 Economic Impacts Model ........................................................................ 5-1 

5.2 Input Data for the Model.......................................................................... 5-3 

5.2.1 Estimation of California-Supplied Goods and Services............ 5-4 

5.2.2 Costs Versus Deployment Year............................................... 5-10 

5.3 Base Case Economic Impacts Analysis Results .................................... 5-10 

5.4 Economic Impacts Sensitivity Analysis................................................. 5-15 

5.5 Fiscal Impacts ........................................................................................ 5-18 

6.0 Cost and Value of CSP Energy............................................................................ 6-1 

6.1 The Market Price Referent....................................................................... 6-1 

6.2 Cost of Energy Calculations .................................................................... 6-2 

6.3 The Time of Delivery Value of CSP Energy........................................... 6-5 

7.0 Environmental and Hedging Benefits.................................................................. 7-1 

7.1 Reduction in Criteria and CO2 Air Emissions ......................................... 7-1 

7.2 Hedging Impact of CSP on Natural Gas Prices ....................................... 7-2 

7.2.1 Natural Gas Use in the United States ........................................ 7-2 

7.2.2 Natural Gas Use in California ................................................... 7-3 

7.2.3 Natural Gas Prices and Price Volatility..................................... 7-5 

7.2.4 The Hedging Impact of CSP Deployment in California ........... 7-6 

April 21, 2006 TC-1 
NREL CA Solar Benefits Contents 

Contents (Continued) 

8.0 Conclusions.......................................................................................................... 8-1 

Appendix A Technology Assessment 

Tables 

Table ES-1 Power Plant Characteristics .........................................................................1 

Table ES-2 Delivered Levelized Energy Cost and Economic Impacts for CSP 

and Gas Technologies in 2015 ($2005) .......................................................3 

Table 3-1 Concentrating Solar Power Technical Potential ...................................... 3-1 

Table 4-1 Deployment Scenarios ............................................................................. 4-3 

Table 5-1 CSP Plant Capital Cost Breakdowns, 2005 $1,000 ................................. 5-5 

Table 5-2 CSP O&M Cost Breakdowns, 2005 $1,000............................................. 5-5 

Table 5-3 Combined Cycle and Simple Cycle Plant Assumptions.......................... 5-6 

Table 5-4 Conventional Combustion Turbine Power Generation Capital 

Cost Breakdowns, 2005 $1,000 ............................................................... 5-6 

Table 5-5 Conventional Combustion Turbine Power Generation O&M 

Cost Breakdowns, 2005 $1,000 ............................................................... 5-7 

Table 5-6 Base Case Breakdown of Expenditures in Southern California, 

percent...................................................................................................... 5-8 

Table 5-7 Base Case Direct and Indirect Economic Impacts of One 

100 MW CSP Plant in 2008 ($2005) ..................................................... 5-11 

Table 5-8 Total Economic Impacts of One CSP or Conventional Plant in 

2008 per 100 MW ($2005) .................................................................... 5-12 

Table 5-9 Total Present Value of CSP Development for Two Deployment 

Scenarios ($2005) .................................................................................. 5-14 

Table 5-10 Material Expenditures in California Sensitivity Criteria, percent ......... 5-16 

Table 6-1 Financial Assumptions for Cost of Energy Calculations......................... 6-3 

Table 6-2 Levelized Cost Comparison..................................................................... 6-4 

Table 7-1 Emissions Reduction by CSP Plants........................................................ 7-2 

Figures 

Figure ES-1 California Electric Power Sector, Annual Average Natural Gas 

Prices, $ per Mcf..........................................................................................3 

Figure 2-1 CSP Systems ............................................................................................ 2-1 

Figure 3-1 Direct Normal Radiation Solar Resource Land Greater Than 

1 Percent Slope Excluded ........................................................................ 3-2 

April 21, 2006 TC-2 
NREL CA Solar Benefits Contents 

Figures (Continued) 

Figure 4-1 California Renewable Portfolio Standard ................................................ 4-2 

Figure 5-1 Base Case Employment Impact Comparison......................................... 5-13 

Figure 5-2 CSP Low and High Deployment Scenarios........................................... 5-13 

Figure 5-3 Low and High Deployment Scenarios Total Impact to Earnings 

and Employment .................................................................................... 5-15 

Figure 5-4 Construction Economic Impacts Sensitivity Analysis for 

100 MW CSP Plant................................................................................ 5-17 

Figure 5-5 Construction Economic Impacts Sensitivity Analysis of Low and 

High CSP Deployment Scenarios .......................................................... 5-18 

Figure 6-1 Conceptual Generation Scenario with Storage ........................................ 6-5 

Figure 7-1 Historic and Forecast Natural Gas Demand by Sector (NPC 

2002) ........................................................................................................ 7-3 

Figure 7-2 Breakdown of US Capacity Additions by On-Line Date (MW).............. 7-4 

Figure 7-3 California’s Natural Gas Sources for 2004.............................................. 7-4 

Figure 7-4 California Electric Power Sector, Annual Average Natural Gas 

Prices, $ per MCF .................................................................................... 7-5 

Figure 7-5 Generation Sources for California Electricity in 2004 ............................ 7-7 

Figure 7-6 Annual Variation in Renewable Energy Project Capacity Factors.......... 7-8 

Figure 7-7 Effect of CSP Deployment on Statewide Generation Cost 

(Current Portfolio with $7.00/MMBtu gas = 100)................................... 7-9 

April 21, 2006 TC-3 
NREL CA Solar Benefits Executive Summary 

Executive Summary 

 This study provides a summary assessment of concentrating solar power (CSP) 

and its potential economic return, energy supply impact, and environmental benefits for 

the State of California. Emphasis was placed on in-state economic impact in terms of 

direct and indirect employment created by the manufacture, installation, and operation of 

CSP plants. The environmental impact of CSP relative to natural gas fueled counterparts 

was studied. The value of CSP as a hedge against natural gas price increases and 

volatility was also analyzed. 

 Black & Veatch chose a 100 MW parabolic trough plant with 6 hours of storage as 

the representative CSP plant to focus the results of the study. Cumulative deployment 

scenarios of 2,100 MW and 4,000 MW between 2008 and 2020 were assumed. Based on 

estimates provided by the National Renewable Energy Laboratory (NREL), future CSP 

technology improvements were incorporated into the study by assuming that 150 MW 

and 200 MW plants would be constructed starting in 2011 and 2015, respectively. The 

NREL estimates include reduced installed costs over time as a result of technology 

learning and increased construction efficiency. The levelized cost of electric production 

was calculated for each CSP plant. 

 There are indications that recently bid trough plants may have somewhat lower 

capital costs than those used in this report; however, these data are not publicly available. 

Overall, while lower capital costs can somewhat lower the economic impact in 

California, the decrease is not expected to significantly change the conclusions of this 

report. 

 Currently (and for the foreseeable future), natural gas fueled combustion turbine 

based power plants are the most frequent choice for new power plants in California. As 

suggested in Table ES-1, the utility electric supply needs served by simple cycle and 

combined cycle plants tend to be those that might be served by CSP with storage. Thus, 

these two gas technologies are identified as conventional technology benchmarks for 

comparison of CSP competitiveness and economic impacts. 

Table ES-1 

Power Plant Characteristics 

Typical Size Typical Duty Capacity Factor 

Simple Cycle 85 MW Peaking 10 percent 

Combined Cycle 500 MW Intermediate 40 percent 

CSP with 6 Hours Storage 100 to 200 MW Intermediate or Peaking 40 percent 

April 21, 2006 ES-1 
NREL CA Solar Benefits Executive Summary 

 A comparison of the levelized cost of energy (LCOE) revealed that the LCOE of 

$148 per MWh for the first CSP plants installed in 2009 is competitive with the simple 

cycle combustion turbine at an LCOE of $168 per MWh, assuming that the temporary 

30 percent Investment Tax Credit is extended. The LCOE for the CSP plant is higher 

than the $104 per MWh LCOE of the combined cycle combustion turbine plant.1

 

 The economic impacts of CSP construction and operation were estimated with 

standard economic tools. Black & Veatch used the Regional Input-Output Modeling 

System (RIMS II) developed and maintained by the US Bureau of Economic Analysis. 

This analysis revealed that each 100 MW of CSP results in 94 permanent operations and 

maintenance jobs compared to 56 and 13 for combined cycle and simple cycle 

combustion turbine plants, respectively. In terms of economic return, for each 100 MW 

of installed capacity, the CSP plant was estimated to create about $628 million in impact 

to gross state output compared to an impact of about $64 million for the combined cycle 

plant and $47 million for the simple cycle plant. The higher CSP state economic impacts 

are due, in part, to the greater capital and operating costs of CSP plants. However, 

irrespective of plant cost, it should be noted that a greater percentage of each CSP 

investment dollar is returned to California in economic benefits. For each dollar spent on 

the installation of CSP plants, there is a total impact (direct plus indirect impacts) of 

about $1.40 to gross state output for each dollar invested compared to roughly $0.90 to 

$1.00 for each dollar invested in natural gas fueled generation. 

 For plants installed in the latter stages of the deployment scenarios, CSP cost 

reductions become evident and the solar technology becomes a potentially competitive 

choice for both peaking and intermediate duty cycles. As shown in Table ES-2, CSP 

plants installed in 2015 are projected to exhibit a delivered LCOE of $115/MWh,2

compared with $168/MWh for the simple cycle combustion turbine and $104/MWh for 

combined cycle plants. At a natural gas price of about $8 per MMBtu, the LCOE of CSP 

and the combined cycle plants at 40 percent capacity factor are equal.3

 Note that this 

analysis does not assume improvements to combustion turbine power generation 

technology, which were outside the scope of this study. However, assuming that 

improvements to combustion turbine power generation efficiency and cost are likely to be 

modest, the LCOE of CSP in 2015 is likely to be competitive with combustion turbine 

power generation technologies. 

 

1

 These prices use the California Market Price Referent (MPR) gas price forecast, which is equivalent to 

$6.40/MMBtu escalated at 2.5 percent annually. All dollars are $2005. 2

 With the permanent 10 percent ITC. With the 30 percent ITC, the cost drops to $103/MWh. 

3

 The MPR gas forecast for 2015 is $8/MMBtu. Futures prices on NYMEX were well above $10/MMBtu 

for the last four months of 2005, and are down to roughly $7.50/MMBtu as of April 1, 2006. 

April 21, 2006 ES-2 
NREL CA Solar Benefits Executive Summary 

Table ES-2 

Delivered Levelized Energy Cost and Economic Impacts for CSP 

and Gas Technologies in 2015 ($2005) 

Delivered 

Energy Cost 

Permanent Jobs, 

per 100 MW 

GSP, $million 

per 100 MW 

Simple Cycle* $187/MWh 13 $47 

Combined Cycle* $119/MWh 56 $64 

CSP with 6 Hours Storage** $115/MWh 94 $628 

*The 2015 MPR natural gas price of $8.00 per MMBtu escalating at 2.5 percent annually was 

used. 

**CSP assumes permanent 10 percent ITC. 

 CSP is a fixed cost generation resource - that is the cost of generating each MWh 

of electricity is primarily dependent on the capital cost of the facility, rather than on fuel 

costs as is the case with natural gas fueled generation. Therefore, installation of more 

fixed-cost generation on the California electric system could reduce the effect on 

electricity prices resulting from natural gas price increases and volatility. This is relevant 

to current generation investment decisions because of recent natural gas price volatility 

and price increases as shown on Figure ES-1. 

2.23 2.71 3.08 2.79 2.76

5.88

9.40

3.82

5.49

6.05

7.76

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

$ per Mcf

Figure ES-1 

California Electric Power Sector, Annual Average Natural Gas Prices, $ per Mcf 

(Source: Energy Information Administration)4

 

4

 Data for 2005 is for January through November only. Data found at www.eia.doe.gov. 

April 21, 2006 ES-3 
NREL CA Solar Benefits Executive Summary 

 Recent studies have suggested that the installation of CSP, wind or other non-gas 

plants in lieu of new natural gas fueled generators can relieve a portion of the demand 

pressure behind gas price volatility. Lawrence Livermore Laboratory and others suggest 

that the natural gas price could decline by one to four percent for each change of 

1 percent in demand. The 4,000 MW high deployment scenario could result in a savings 

of $60 million per year for natural gas in California for a 1 percent price reduction for a 

1 percent usage reduction. At the higher price impact range, the California savings could 

be four times greater. 

 Power generation with CSP technology does not result in any significant air 

emissions compared with a business as usual approach. Therefore, if the installation of 

CSP avoids the installation of new natural gas fueled power stations or avoids the 

operation of existing power stations, there would be a net reduction in air emissions in 

California. Using the natural gas combined cycle plant – the cleanest, most efficient 

fossil technology – as a proxy, data for criteria air emissions reductions were developed. 

For the 4,000 MW deployment scenario, at least 300 tons per year of NOx and 7.6 million 

tons per year of CO2 would be avoided. If the fossil displacement is simple cycle gas 

turbines or coal fired plants, these values would be larger. 

 Black & Veatch has made the following conclusions about the deployment of CSP 

from this analysis: 

• California has high quality solar resources sufficient to support far more 

CSP than either the 2,100 MW or 4,000 MW scenarios analyzed. 

• Depending on the CSP plant interconnection point and the load profile of 

the local electricity provider, CSP with 6 hours of storage could perform 

peaking and/or intermediate generation roles for a utility. 

• Investment in CSP power plants delivers greater return to California in 

both economic activity and employment than corresponding investment in 

natural gas equipment: 

- Each dollar spent on CSP contributes approximately $1.40 to 

California’s Gross State Product; each dollar spent on natural gas 

plants contributes about $0.90 - $1.00 to Gross State Product. 

- The 4,000 MW deployment scenario was estimated to create about 

3,000 permanent jobs from the ongoing operation of the plants. 

• Operations period expenditures on operations and maintenance for CSP 

create more permanent jobs than alternative natural gas fueled generation. 

For each 100 MW of generating capacity, CSP was estimated to generate 

94 permanent jobs compared to 56 jobs and 13 jobs for combined cycle 

and simple cycle plants, respectively. 

April 21, 2006 ES-4 
NREL CA Solar Benefits Executive Summary 

• Energy delivered from early CSP plants (startup in 2007) costs more than 

that delivered from natural gas combined cycle plants5 ($157 per MWh vs. 

$104 per MWh, based on a 30 percent ITC for CSP). With technology 

advancements, improvements to CSP construction efficiency, and with 

higher gas prices consistent with 2015 MPR projections, CSP becomes 

competitive with combined cycle power generation ($115 per MWh vs. 

$119 per MWh, even with the permanent 10 percent ITC). Most of the 

economic and employment advantages are still retained. 

• CSP plants are a fixed-cost generation resource and offer a physical hedge 

against the fluctuating cost of electricity produced with natural gas. 

• Each CSP plant provides emissions reductions compared to its natural gas 

counterpart; the 4,000 MW scenario in this study offsets at least 300 tons 

per year of NOx emissions, 180 tons of CO emissions per year, and 

7,600,000 tons per year of CO2. 

 The economic and employment benefits, together with delivered energy price 

stability and environmental advantages, suggest that the CSP solar alternative would be a 

beneficial addition to California’s energy supply. While early CSP plants are more costly 

than their traditional gas counterparts, subsequent plants are estimated to become nearly 

cost competitive on a levelized cost of energy basis. 

 

5

 Based on MPR gas prices for 2007, $6.40/MMBtu, and assuming a 100 MW CSP plant with 6 hours 

storage and a 500 MW combined cycle plant. Both CSP and combined cycle plants operate at 40 percent 

capacity factor. All dollars are $2005. 

April 21, 2006 ES-5 
NREL CA Solar Benefits Introduction 

1.0 Introduction 

 This report documents work performed by Black & Veatch Corporation (Black & 

Veatch) on the “Economic, Energy, and Environmental Benefits of Concentrating Solar 

Power in California,” a study funded by the National Renewable Energy Laboratory 

(NREL) under subcontract AEK-5-55036-01. The objective of the study was to 

characterize commercial and developing CSP technologies and estimate the direct and 

indirect economic impacts of CSP deployment. The economic impact of CSP 

deployment was calculated by considering the impact to Gross State Output, earnings, 

employment, and to state tax receipts. The study was divided into five tasks: 

• Task 1: Technology Assessment 

• Task 2: Solar Resource Assessment 

• Task 3: Cost of Energy and Economic Impact Evaluation 

• Task 4: Environmental and Energy Attributes and Specific Benefits to 

California 

• Task 5: Review and Reporting 

 This report relies on information gathered by the Black & Veatch team which 

performed the “New Mexico Concentrating Solar Plant Feasibility Study,” performed for 

the New Mexico CSP Task Force under contract to New Mexico Energy, Minerals and 

Natural Resources Department. The study also made extensive use of Excelergy, the 

NREL solar parabolic trough performance and cost modeling program. Economic 

impacts were calculated using the Regional Input-Output Modeling System (RIMS II 

model), developed and maintained by the US Bureau of Economic Analysis. 

April 21, 2006 1-1 
NREL CA Solar Benefits CSP Technology Assessment 

2.0 CSP Technology Assessment 

 Concentrating solar thermal power plants produce electric power by converting 

the sun’s energy into high temperature heat using various mirror or lens configurations. 

Solar thermal systems (trough, dish-Stirling, power tower), transfer heat to a turbine or 

engine for power generation. Concentrating photovoltaic (CPV) plants provide power by 

focusing solar radiation onto a photovoltaic (PV) module, which converts the radiation 

directly to electricity. Figure 2-1 shows pictures of collectors for each of these 

technologies. 

Parabolic Trough Parabolic Dish-Engine 

Power Tower Concentrating Photovoltaic 

Figure 2-1 

CSP Systems 

(Source: NREL) 

April 21, 2006 2-1 
NREL CA Solar Benefits CSP Technology Assessment 

2.1 Description of Technologies 

 This section provides a brief description of the four CSP technologies. A more 

complete description is provided in Appendix A. 

 Parabolic trough systems comprise rows of trough-shaped mirrors which direct 

solar insolation to a receiver tube along the focal axis of each trough. The focused 

radiation raises the temperature of heat-transfer oil, which is used to generate steam. The 

steam is then used to power a turbine-generator to produce electricity. 

 Power tower systems consist of a field of thousands of sun-tracking mirrors which 

direct insolation to a receiver atop a tall tower. A molten salt heat-transfer fluid is heated 

in the receiver and is piped to a ground based steam generator. The steam drives a steam 

turbine-generator to produce electricity. 

 Because trough and power tower systems collect heat to drive central turbinegenerators, they are best suited for large-scale plants: 50 MW or larger. Trough and 

tower plants, with their large central turbine generators and balance of plant equipment, 

can take advantage of economies of scale for cost reduction, as cost per kW goes down 

with increased size. Additionally, these plants can make use of thermal storage or hybrid 

fossil systems to achieve greater operating flexibility and dispatchability. This provides 

the ability to produce electricity when needed by the utility system, rather than only when 

sufficient solar insolation is available to produce electricity, for example, during short 

cloudy periods or after sunset. This capability has significantly more value to the utility 

and potentially allows the owner of the CSP plant to receive additional credit, or 

payment, for the electric generating capacity of the plant. 

 Parabolic dish systems use a dish shaped arrangement of mirror facets to focus 

energy onto a receiver at the focal point of the collector. A working fluid such as 

hydrogen is heated in the receiver, and drives a turbine or Stirling engine. Most current 

dish applications use Stirling engine technology because of its high efficiency. 

 CPV systems use either parabolic dish mirror systems or a large array of flat 

Fresnel lenses to focus energy on PV cells. The PV cells generate direct current 

electricity, which is converted to alternating current using a solid state inverter. 

 Dish and CPV systems are modular in nature, with single units producing power 

in the range of 10 kW to 35 kW. Thus, dish and CPV systems could be used for 

distributed or remote generation applications, or in large arrays of several hundred or 

thousand units to produce power on a utility scale. Dish and CPV systems have the 

potential advantage of mass production of individual units, similar to the mass production 

of automobiles or wind turbines. At this time, neither the dish Stirling or CPV system use 

storage or hybrid fossil capabilities to provide a firm resource. CPV systems could, of 

course, make use of battery energy storage; however, present battery storage technology 

is comparatively inefficient and expensive. 

April 21, 2006 2-2 
NREL CA Solar Benefits CSP Technology Assessment 

2.2 Commercial Status of Technologies 

 The largest group of solar systems in the world is the Solar Energy Generating 

Systems (SEGS) I through IX parabolic trough plants in the Mohave Desert in southern 

California. The SEGS plants were built between 1985 and 1991 and have a total capacity 

of 354 MW. These plants have generally performed well over their 15 to 20 years of 

operation. There are several other commercial trough projects in the planning or active 

project development stage, including a 64 MW plant in Nevada and several 50 MW 

plants in Spain. Integrated Solar Combined Cycle Systems (ISCCS) are in various stages 

of planning in southern California, India, Egypt, Morocco, Mexico, and Algeria. A 

1 MW trough plant was recently constructed for Arizona Public Service (APS), and is 

currently in startup. 

 There are no operating commercial dish-Stirling power plants. Recently, 

installation was completed on a six dish test deployment at Sandia National Laboratories 

(SNL) in Albuquerque. This development is under a joint agreement between Stirling 

Engine Systems (SES) (Phoenix) and SNL. On August 2, 2005, Southern California 

Edison publicly announced the completion of negotiations on a 20-year power purchase 

agreement with SES for between 500 to 850 MW of capacity (producing 1,182 to 

2,010 GWh per year) using parabolic dish units. On September 7, 2005, SES announced 

a contract with San Diego Gas & Electric to provide between 300 and 900 MW of solar 

power using the dish technology. Pricing for these power purchase agreements remains 

confidential. These large deployments of dish Stirling systems are expected to drastically 

reduce capital and O&M costs and to result in increased system reliability. 

 There are no commercial power tower plants in operation. The 10 MW Solar One 

plant near Barstow, California, operated from 1982 to 1988 and produced over 38 GWh 

of electricity. Solar One generated steam directly in the receiver. To implement 

improved heat transfer and thermal storage, the plant was retrofitted with a receiver, 

storage system, and steam generator using a molten salt heat transfer fluid. The 

retrofitted plant, named Solar Two, operated from 1998 to 1999. In addition to Solar One 

and Solar Two, experimental and prototype systems have operated in Spain, France, and 

Israel. Abengoa in Spain has announced an 11 MW project called PS 10. ESKOM, the 

state-owned utility in South Africa, is considering a 100 MW molten-salt plant. A 

17 MW molten salt plant in Spain, Solar Tres, was planned by Ghersa, Boeing, and 

Nexant. However, execution of this project appears to be unlikely at this time. 

 CPV systems are being offered by Amonix, Inc., a US manufacturer, and Solar 

Systems Pty, Ltd, an Australian firm. These systems are offered in 25-35 kW sizes. 

There are 547 kW of Amonix systems deployed at APS. Planned deployments in the near 

future include 10 to 20 MW in Spain. Ten Solar Systems dish PV systems have been 

deployed since 2003, for a total capacity of 220 kW, with the construction of an 

April 21, 2006 2-3 
NREL CA Solar Benefits CSP Technology Assessment 

additional 720 kW under way. Several contracts are anticipated in the relatively near 

future in the US Southwest to comply with Renewable Portfolio Standard (RPS) 

requirements. 

2.3 Technology Selection for Benefits Analysis 

 Black & Veatch has chosen the parabolic trough technology as the CSP proxy for 

economics benefits analysis because much more detailed information on construction and 

operation costs and performance is available for this technology than other CSP 

technologies. Detailed information on the amount of material and labor for plant 

construction and operation is needed to develop a reasonable economic impacts analysis. 

There are currently 354 MW of trough generation in the SEGS plants in southern 

California, a 64 MW plant under construction in Nevada, and several 50 MW or larger 

trough plants are in various stages of development around the world. Other technologies 

do not have significant commercial operating experience. 

 The use of trough as a proxy is not intended to suggest that future CSP 

installations will not include significant amounts of generation using other CSP 

technologies. 

April 21, 2006 2-4 
NREL CA Solar Benefits California CSP Resource Assessment 

3.0 California CSP Resource Assessment 

 Concentrating solar systems make use of direct normal insolation (DNI), that part 

of the radiation which comes directly from the sun. Insolation is typically rated as a 

power density in units of kW/m2

, Btu/h-ft2, or MJ/h-m2. In this report, instantaneous DNI 

is provided in units of kW/m2

 and daily average DNI is provided in units of kWh/m2/day. 

 The daily amount of DNI is seasonal, with greatest DNI on days close to the 

summer solstice, and least DNI on days near the winter solstice. The average annual 

daily DNI for high insolation (low cloud cover) areas of California ranges from 

6.75 kWh/m2/day to 8.25 kWh/m2/day. Annual electrical energy production from CSP 

plants is roughly proportional to the annual average DNI level. 

 Black & Veatch calculated the total land area in California with sufficient 

resource to support power generation on comparably flat land outside of environmentally 

sensitive areas by using solar insolation data provided by NREL. Figure 3-1 shows 

available land with high solar resource and land slope not greater than 1 percent, a 

preference for trough and power tower plants. The land area for each technology type, 

along with potential generation capacity in MW and GWh, is presented in Table 3-1. 

Capacity and generation were based on CSP systems without thermal storage. The table 

shows that with each CSP power generation technology there is the potential to generate 

many multiples of the current demand for electricity in California. The total generation 

capacity as of 2004 for the state was roughly 58,000 MW.6

 

 

Table 3-1 

Concentrating Solar Power Technical Potential 

Solar 

Resource Land 

Area, mi2

Capacity 

Potential, MW 

Generation 

Potential, 

GWh 

Parabolic Trough, no storage < 1 % slope 5,900 661,000 1,614,000 

Parabolic Trough, six hours storage < 1 % slope 5,900 471,000 1,640,000 

Power Tower, six hours storage < 1 % slope 5,900 342,000 1,233,000 

Parabolic Dish, < 3 % slope 11,600 1,480,000 3,371,000 

Parabolic Dish, < 5 % slope 14,400 1,837,000 4,196,000 

Concentrating PV, < 3 % slope 11,600 1,235,000 2,859,000 

Concentrating PV, < 5 % slope 14,400 1,534,000 3,558,000 

 

6 www.eia.doe.gov. This is net summer capacity. 

April 21, 2006 3-1 
NREL CA Solar Benefits California CSP Resource Assessment 

Figure 3-1 

Direct Normal Radiation Solar Resource Land Greater Than 1 Percent Slope Excluded 

(Source: NREL) 

April 21, 2006 3-2 
Deployment of 

NREL CA Solar Benefits CSP Plants in California 

4.0 Deployment of CSP Plants in California 

 Black & Veatch developed aggressive, but reasonable, CSP deployment scenarios 

collaboratively with NREL to calculate the economic impact of CSP deployment 

(Section 5.0). By stating that the deployment scenarios are aggressive, Black & Veatch 

recognizes that CSP commercialization requires a long-term view that may not be 

supported by current economics or utility preferences. The cost of energy from the first 

100 MW CSP plant may be high compared to alternative conventional (fossil fueled) or 

renewable energy generation options. However, CSP has the potential to be an important 

generation resource for California (and other southwest US states) in developing a 

balanced power generation portfolio. 

 One consideration in developing scenarios is the need for new power plants. 

According to the State of California “Energy Action Plan,”7

 dated May 8, 2003, 

California’s peak electric demand was 52,863 MW on July 2, 2002. According to the 

Action Plan, peak demand is projected to grow at 2.4 percent annually. Platts Research 

Service forecasts electric demand to grow from 54,320 MW in 2005 to 77,759 MW in 

2020 in the “Power Outlook Quarter 1 2005.”8 Platts also estimates that nearly 10,000 

MW of generation capacity will be retired over this time frame. Therefore, Platts 

estimated that nearly 33,000 MW of generation capacity additions will be required to 

meet growing demand. The estimate for growth in energy demand is from 295,000 GWh 

in 2005 to 422,000 GWh in 2020, or a growth of 127,000 GWh. 

 Another consideration in developing scenarios is the California Renewable 

Portfolio Standard (RPS), which currently mandates that 20 percent of energy be 

generated by renewables by 2017. The California Energy Commission (CEC) has set an 

accelerated goal of 20 percent by 2010. Figure 4-1 shows the level of renewable energy 

generation in California through 2003 with projected requirements for 2010, 2017, and a 

more aggressive proposed goal of 33 percent by 2020. The RPS applies only to investor 

owned utilities (IOUs), such that only San Diego Gas & Electric, Southern California 

Edison, and Pacific Gas & Electric are subject to the RPS. However, municipally owned 

utilities such as Los Angeles Department of Water and Power and Sacramento Municipal 

Utility District are mandated by legislation to develop appropriate renewable plans that 

follow the spirit of the RPS. Therefore, renewable energy generation would need to 

increase to 34,200 GWh/y above the 2004 level of 28,300 GWh to achieve the 20 percent 

RPS by 2017. 

 

7

 Available from the California Energy Commission at 

http://www.energy.ca.gov/energy_action_plan/2003-05-08_ACTION_PLAN.PDF. 8

 Platts Power Outlook service (www.platts.com). 

April 21, 2006 4-1 
Deployment of 

NREL CA Solar Benefits CSP Plants in California 

0

20,000

40,000

60,000

80,000

100,000

120,000

1983 1988 1993 1998 2003 2008 2013 2018

Adopted Goal

20% by 2010

Proposal

33% by 2020

Statutory

Requirement

20% by 2017

2003 Total for all US Non-Hydro RE

Historical CA Non-Hydro Generation

Figure 4-1 

California Renewable Portfolio Standard 

 As discussed in Section 2.2, Black & Veatch has used trough plants with six hours 

of storage as the proxy for CSP generation expansion. The use of trough as a proxy is not 

intended to suggest that future CSP installations will not include significant amounts of 

generation using other technologies. The announcement of 20 year power purchase 

agreements between SES and Southern California Edison and San Diego Gas & Electric 

for a total of between 800 MW and 1,750 MW of dish engine power generation indicates 

strong commercial viability for dish systems. 

 Each 1,000 MW of parabolic trough systems, with six-hours of storage, will 

generate about 3,600 GWh/yr. Thus, thousands of MW of parabolic trough could, 

theoretically, be installed to meet state electric demand and RPS requirements. However, 

utilities install or purchase renewable energy on a least cost best fit (LCBF) basis. 

Should selected projects have energy costs which exceed the Market Price Referent 

(MPR), the project owner can file for payments of the energy cost exceeding the MPR 

from the state’s New Renewable Facilities Program. Should funds not be available, the 

utility is relieved of its obligation to meet the RPS requirement. Additional information 

on the California MPR and its impact on CSP is provided in Section 6.1. 

 Because there is no viable approach for calculating CSP deployment on the basis 

of LCBF, Black & Veatch has opted to use a scenario basis for subsequent economic 

impact calculations. It has been assumed that the cumulative installation of CSP plants 

by 2020 will be between 2,100 MW and 4,000 MW (or about 8 to 18 percent of the peak 

demand growth). The Low and High Scenarios are summarized in Table 4-1. The Low 

Scenario provides a cumulative 2,100 MW of CSP addition by 2020, somewhat below 

April 21, 2006 4-2 
Deployment of 

NREL CA Solar Benefits CSP Plants in California 

10 percent of the projected demand growth as well as about 10 percent of the IOU RPS 

requirement. The High Scenario provides a cumulative 4,000 MW for about 18 percent 

of the demand growth per Platts, and about 20 percent of the IOU RPS requirement. 

Table 4-1 

Deployment Scenarios 

Low Scenario High Scenario 

Year 

Plant 

Size 

(MW) 

Number 

of Plants 

Annual 

MW 

Cumulative 

MW 

Number of 

Plants 

Annual 

MW 

Cumulative 

MW 

2008 100 1 100 100 1 100 100 

2009 100 1 100 200 1 100 200 

2010 100 1 100 300 1 100 300 

2011 150 1 150 450 1 150 450 

2012 150 1 150 600 1 150 600 

2013 150 1 150 750 2 300 900 

2014 150 1 150 900 2 300 1,200 

2015 200 1 200 1,100 1 200 1,400 

2016 200 1 200 1,300 2 400 1,800 

2017 200 1 200 1,500 2 400 2,200 

2018 200 1 200 1,700 3 600 2,800 

2019 200 1 200 1,900 3 600 3,400 

2020 200 1 200 2,100 3 600 4,000 

April 21, 2006 4-3 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

5.0 Economic Impacts of CSP in California 

 Utilities are charged with planning generation portfolios which provide a safe, 

adequate, and reliable supply of electricity at the lowest reasonable cost and in an 

environmentally acceptable manner. Practically, this objective has translated into utilities 

selecting the lowest cost generation sources. Despite the propensity of utilities to 

purchase the lowest-cost resources, it has long been recognized that there can be 

significant socioeconomic impacts associated with new power plant investments. It 

follows that power plants of different types with different characteristics will have 

different socioeconomic impacts. The goal of this study is to estimate the impact to the 

regional economy of developing CSP plants in California and to compare these impacts 

to regional economic impacts generated by building conventional fossil fueled power 

stations. The direct and indirect impacts of constructing one CSP plant and a series of 

CSP plants over the next 15 years have been estimated. 

5.1 Economic Impacts Model 

 The purpose of the economic impacts model is to determine the direct and indirect 

economic impact of developing CSP plants in California. Direct economic impacts are 

the dollars directly spent by the project in the region on materials, equipment, and wages. 

Indirect economic impacts are also referred to as the “multiplier” impacts of each dollar 

spent in the region. These impacts are created when a dollar is spent on goods or services 

produced by suppliers in the region. For example, if a dollar is spent on equipment 

manufactured in the region, the manufacturer spends a portion of this dollar to hire 

additional employees, expand production and purchase goods and services. The degree 

to which a dollar spent on a particular industry is re-spent in the region is the “multiplier” 

for that industry. The following economic metrics can be used to measure the direct and 

indirect economic impact of dollars spent in a given region: 

• Gross State Output--The total value of goods and services produced within 

the state. 

• Earnings--The value of wages and benefits earned by workers in the 

region. 

• Employment--Full and part-time jobs. 

• Fiscal--Impact to tax receipts by the state and local governments. 

The economic impacts of a power generation project can be divided into the 

construction and operation periods. During the construction phase of the project, there is 

a direct economic impact from the portion of goods and services for the project purchased 

from local vendors. For example, local labor is used for construction and concrete is 

April 21, 2006 5-1 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

purchased from a local concrete plant. There are also indirect economic impacts, which 

include employment created by purchases from vendors and multiplier impacts in the 

regional economy. During the operation phase of the project, there is a direct impact 

from permanent jobs created by the plant and annual purchases of goods and services to 

support operations and maintenance of the plant. There are also multiplier impacts 

created by the annual plant operations and maintenance expenditures. 

 The model chosen for this study is the Regional Input-Output Modeling System 

(RIMS II model), developed and maintained by the US Bureau of Economic Analysis. 

This is a regional input-output (I-O) model that measures the interdependency of the 

various sectors of the economy through the establishment of an accounting matrix. The 

matrix shows the change in output, earnings, and employment in each industry due to a 

change in final demand (purchases from that industry). The RIMS II model is well suited 

for the needs of this study because it can estimate economic impacts for any county or 

combination of counties in the US, and includes multipliers for nearly 500 industry 

classifications. For this analysis, the region of study was established to be southern 

California, including the following counties. 

• Fresno 

• Imperial 

• Inyo 

• Kern 

• Kings 

• Los Angeles 

• Mono 

• Orange 

• Riverside 

• San Bernardino 

• San Diego 

• San Luis Obispo 

• Santa Barbara 

• Tulare 

• Ventura 

The economic analysis was limited to counties in southern California because the 

solar resource suitable for CSP is primarily available in southern California; thus, it has 

been assumed that the economic impact of CSP development would be concentrated in 

southern California. 

 The multiplier analysis included the evaluation of impacts arising from the 

construction and operation periods. The results for each period were then summed to 

arrive at the total impact for developing one and multiple CSP plants. For the 

construction and operation periods, the cost estimates were broken into major equipment 

and labor categories (e.g., solar field mirrors, construction labor, etc.). The percent of 

labor and capital expenditures in each category that would occur in southern California 

were then estimated. The following section contains a complete discussion of the 

technical inputs to the economic model. 

April 21, 2006 5-2 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

 The expenditures in southern California were then multiplied by the final demand 

multipliers for the respective industries for each major capital and labor expense. This 

impact estimate was then added to the initial change due to the investment. Gross State 

Output, earnings and output estimates were then deflated to 1997, the basis for the I-O 

tables in the RIMS II model. Final results were then escalated to 2005 dollars. All 

estimates during construction were performed on a per MW basis. A similar process was 

followed for the operation period, based on the annual expenditures made per CSP plant 

per year. This estimate included expenditures for plant staff, consumables and supplies, 

land rent, and other cost items. Economic impact estimates for the operation period are 

provided on per MW and per MWh basis. 

 The economic impacts of CSP deployment were then compared with the 

economic activity generated by 500 MW combined cycle and 85 MW simple cycle 

combustion turbine plants. These plants provide similar electric services to what a CSP 

plant provides and offer a basis for estimating the relative impacts of this renewable 

technology. Sizing of the combined cycle and simple cycle plants are typical sizes for 

plants built for intermediate and peaking service. 

5.2 Input Data for the Model 

 An important element of the economic impact analysis is the estimation of capital 

and annual operations and maintenance (O&M) costs. The magnitude of the capital and 

annual expenditures directly impacts the magnitude of the direct and indirect economic 

impacts. Black & Veatch used data from the Excelergy Model, developed and maintained 

by NREL.9 Capital and O&M costs were generated for parabolic trough systems with six 

hours of storage for a 100 MW plant built in 2007, a 100 MW plant built in 2009, a 

150 MW plant built in 2011, and a 200 MW plant built in 2015. 

 There are indications that recently bid trough plants may have somewhat lower 

capital costs than those generated by Excelergy; howerver, these data are not publicly 

available. Overall, while lower capital costs can somewhat lower the economic impact in 

California, the decrease is not expected to significantly change the conclusions of this 

report. 

 

9

 Excelergy is an Excel spreadsheet-based model for solar parabolic trough systems. Developed by NREL, 

it models annual plant performance and estimates capital and O&M costs. It uses a time step approach with 

hourly or finer time increment solar and weather data. Excelergy has been benchmarked against the SEGS 

plants. 

April 21, 2006 5-3 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

 The Excelergy-generated capital cost estimates are based on data from the SEGS 

plants, vendor inquiries, and various studies. NREL has developed “Learning Curves” to 

describe the reduction in capital and operating costs observed as more CSP plants are 

deployed. The learning curve cost reductions relate to technology advances, scale up, 

effects of mass production resulting from large scale deployment, and improvements in 

construction efficiency. 

 Table 5-1 is a summary of capital costs for the four CSP plants. Black & Veatch 

worked from a more detailed cost breakdown to place equipment costs into 

“Manufactured in southern California” and “Not Manufactured in southern California” 

categories. Table 5-2 is a summary of annual O&M costs for the four CSP plants. 

 Black & Veatch also estimated the direct and indirect economic impact of 

constructing and operating combined cycle and simple cycle combustion turbine plants. 

Because these plants provide intermediate and peaking electric services similar to those 

of a CSP plant, they offer a good benchmark to the economic impacts created by CSP. 

Table 5-3 provides the input assumptions for the combined cycle and simple cycle 

combustion turbine plants. Capital and operating cost breakdowns were also developed 

for both plant types based on Black & Veatch experience with each of these plant types to 

estimate the direct and indirect economic impact of constructing each plant in southern 

California. 

 Table 5-4 provides a summary capital cost breakdown and Table 5-5 provides an 

O&M cost breakdown for the combined cycle and simple cycle combustion turbine 

power plants, respectively. Black & Veatch worked from a more detailed cost breakdown 

to place equipment costs into “Manufactured in southern California” and “Not 

Manufactured in southern California” categories. 

5.2.1 Estimation of California-Supplied Goods and Services 

 The RIMS II model calculates the economic impact of expenditures inside of a 

given region; therefore, the part of capital and operating costs spent in and out of 

southern California must be determined. Black & Veatch first divided the total capital 

and operating cost estimates into material and labor components. It has been assumed 

that all construction and operations labor jobs created are in southern California. 

 The plant cost estimates were examined on a line by line basis and percentages 

were applied, based on engineering judgment and knowledge of suppliers, as to what 

portion of the equipment purchased for the plant would be manufactured in southern 

California. Some of the material and equipment is available from southern California 

manufacturers, while other specialized items are not. Table 5-6 shows the base case 

assumptions used regarding equipment purchases in California. Section 5.4 provides a 

sensitivity analysis with lower and higher in-state spending assumptions. 

April 21, 2006 5-4 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

Table 5-1 

CSP Plant Capital Cost Breakdowns, 2005 $1,000 

2007 

100 MW* 

2009 

100 MW* 

2011 

150 MW* 

2015 

200 MW* 

Site Work and Infrastructure 2,455 2,433 2,566 2,681 

Solar Field 230,865 205,109 243,059 268,441 

HTF System 10,009 9,895 11,896 13,542 

Thermal Energy Storage 57,957 57,937 71,320 89,390 

Power Block 38,754 38,754 48,899 56,818 

Balance of Plant 22,533 22,533 28,432 33,036 

Contingency 30,707 28,116 33,742 37,720 

Total Direct Costs 393,280 364,776 439,915 501,627 

Indirects 101,106 92,814 113,469 129,746 

Total Installed Cost 494,386 457,590 553,384 631,373 

Source: NREL Excelergy Model. 

*With 6 hours storage. 

Table 5-2 

Annual CSP O&M Cost Breakdowns, 2005 $1,000 

2007 

100 MW 

2009 

100 MW 

2011 

150 MW 

2015 

200 MW 

Labor 

Administration 528 528 554 554 

Operations 979 973 1,088 1,158 

Maintenance 633 633 664 664 

Total Labor 3,018 2,984 3,517 3,926 

Miscellaneous 419 415 516 599 

Service Contracts 263 259 352 435 

Water Treatment 260 265 413 556 

Spares and Equipment 669 651 870 1,040 

Solar Field Parts and Materials 1,859 1,311 1,457 1,904 

Annual Capital Equipment 226 218 320 418 

Subtotal 3,695 3,119 3,928 4,953 

Total 6,713 6,104 7,445 8,879 

Source: NREL Excelergy Model. 

April 21, 2006 5-5 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

Table 5-3 

Combined Cycle and Simple Cycle Plant Assumptions* 

Combined 

Cycle 

Simple 

Cycle 

Combustion Turbine Technology 2x1 7FA 7EA 

Net Capacity, MW 500 85 

Net Plant Heat Rate, Btu/kWh 7,000 9,700 

Capacity Factor, percent 40 10 

Capital Cost, $/kW 650 500 

Annual O&M Cost (non-fuel), $ 10,705,500 463,500 

Annual Fuel Cost** 78,489,600 4,622,477 

*All costs in 2005 dollars. 

**Assumes a fuel cost of $6.40/MMBtu, escalated at 2.5 percent. This is 

equivalent to the California 2005 Market Price Referent (MPR) natural gas 

forecast. 

Table 5-4 

Conventional Combustion Turbine Power 

Generation Capital Cost Breakdowns, 2005 $1,000 

2x1 7FA 7EA 

Combustion Turbines & Auxiliaries 79,000 22,950 

Heat Recovery Steam Generators 26,000 N/A 

Steam Turbine Generator & Auxiliaries 36,740 N/A 

Balance of Plant 80,150 8,653 

Other Costs 86,982 8,082 

Contingency 16,120 2,795 

Total 324,992 42,480 

Source: Black & Veatch. 

April 21, 2006 5-6 
NREL 

April 21, 200

Economic Impacts of

CA Solar Benefits CSP in California 

6 5-7 

Table 5-5 

Conventional Combustion Turbine Power 

Generation O&M Cost Breakdowns, 2005 $1,000 

 2x1 7FA 7EA 

Staff 2,205 179 

Training & Communications 945 77 

Water 1,511 42 

Major Maintenance 5,289 146 

Other VOM/parts 756 21 

Natural Gas 103,478 3,250 

Total 114,183 3,714 

Source: Black & Veatch. 
NREL CA Solar Benefits 

Table 5-6 

Base Case Breakdown of Expenditures in Southern California, percent 

All Plants 2009 Plant 2011 Plant 2015 P

Plant System 

Percent 

Labor 

Percent 

Material 

Percent of 

Total Project 

Cost 

Percent 

Labor in 

CA 

Percent 

Material in 

CA 

Percent of 

Total 

Project 

Cost 

Percent 

Labor in 

CA 

Percent 

Material in 

CA 

Percent of 

Total Project 

Cost 

Perce

Labor in 

Sitework and Infrastructure 100% 0% 0.4% 100% 0% 0.3% 100% 0% 0.3% 100% Contractor Overhead 0% 100% 8.3% 0% 100% 8.1% 0% 100% 7.4% 0% Heat Collection Elements 0% 100% 11.0% 0% 0% 10.9% 0% 50% 9.9% 0% Mirrors 0% 100% 11.8% 0% 0% 11.7% 0% 50% 10.7% 0% Metal Support Structure 0% 100% 11.5% 0% 50% 11.3% 0% 50% 10.1% 0% Misc. Solar Field Equipment 51% 49% 12.5% 91% 59% 12.2% 91% 59% 10.9% 90% HTF System 7% 93% 2.3% 100% 34% 2.3% 100% 34% 2.2% 100% Thermal Energy Storage 0% 100% 7.8% 0% 42% 9.2% 0% 75% 9.4% 0% Thermal Energy Storage Fluid 0% 100% 6.7% 0% 50% 5.6% 0% 50% 5.8% 0% 

April 21, 2006 
NREL 

April 21, 200

CA Solar Benefits 

6 

Table 5-6 (Continued) 

Base Case Breakdown of Expenditures in Southern California, percent 

All Plants 2009 Plant 2011 Plant 2015 P

Plant System 

Percent 

Labor 

Percent 

Material 

Percent of 

Total Project 

Cost 

Percent 

Labor in 

CA 

Percent 

Material in 

CA 

Percent of 

Total 

Project 

Cost 

Percent 

Labor in 

CA 

Percent 

Material in 

CA 

Percent of 

Total Project 

Cost 

Perce

Labor in 

Power Block 23% 77% 8.4% 100% 12% 8.7% 100% 12% 8.3% 100% Balance of Plant 44% 56% 4.3% 100% 50% 4.5% 100% 50% 4.3% 100% Contingency 18% 82% 6.3% 95% 23% 6.2% 95% 45% 5.7% 95% Engineering, Const. Mgmt 0% 100% 6.6% 0% 50% 6.6% 0% 50% 6.2% 0% EPC Markup 0% 100% 6.3% 0% 30% 6.4% 0% 30% 5.9% 0% Land 0% 100% 0.4% 0% 100% 0.4% 0% 100% 0.5% 0% Owners 30% 50% 2.7% 50% 50% 2.7% 50% 50% 2.5% 50% Source: Black & Veatch. 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

 In general, goods and services purchases for O&M are assumed to be from instate sources. It was assumed that all miscellaneous costs and service contracts were 

southern California based. Water costs are split nearly evenly between raw water costs 

and chemicals. Black & Veatch has assumed 100 percent of the raw water costs are spent 

in southern California, while 50 percent of the chemicals are produced in California. 

Spares and equipment, solar field parts, and capital equipment costs were assumed to be 

50 percent southern California based. 

5.2.2 Costs Versus Deployment Year 

 To simplify the economic impacts analysis, Black & Veatch grouped the 

deployment scenarios into four “buckets,” which contain the following years: 

• 2008, 2009, 2010. 

• 2011, 2012, 2013. 

• 2014, 2015, and 2016. 

• 2017, 2018, and 2019. 

 Black & Veatch used this approach because any difference in plant costs between 

years due to inflation is not within the accuracy of the cost estimates. Therefore, any 

gains in granularity in study results are not significant because of the confidence in the 

cost estimates. 

5.3 Base Case Economic Impacts Analysis Results 

 Black & Veatch estimated the direct and indirect impact of the development of the 

reference parabolic trough CSP plant, described in Section 2.1, in southern California 

with an on-line date in 2008. This section provides the base case analysis. A sensitivity 

analysis is discussed in Section 5.4. Table 5-7 shows that constructing one 100 MW CSP 

plant has a direct impact to Gross State Output of over $150 million and an indirect 

impact of over $470 million. The table also shows that about 455 job-years of direct 

employment are created during the construction of the facility, which equates to over 

$51 million in direct earnings. The table also shows that the plant results in about 38 

permanent jobs directly created by the operation of the plant; another 56 jobs are 

indirectly created by the operation of the plant. 

 Table 5-8 shows the total (direct plus indirect) economic impact per 100 MW of 

CSP, combined cycle and simple cycle combustion turbine plants. Table 5-8 shows that 

the total construction impact of CSP on gross state output at about $626 million per 

100 MW is significantly larger than that for combined cycle or simple cycle combustion 

turbine plants at about $64 million per 100 MW and $47 million per 100 MW, 

respectively. The primary reason for this is the much larger total installed cost of the CSP 

plant, which is estimated to be $4,600 per kW in 2008 compared to the combined cycle 

April 21, 2006 5-10 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

plant at $650 per kW and the simple cycle plant at $500 per kW. However, the CSP plant 

has an impact to gross state output of $1.4 per $1 spent on the CSP plant, while the ratios 

for the combined cycle and simple cycle combustion turbine plants are in the range of 

$0.90 to $1.00 per $1 spent on the fossil fueled plants. 

Table 5-7 

Base Case Direct and Indirect Economic Impacts 

of One 100 MW CSP Plant in 2008 ($2005) 

Direct Impact Indirect Impact 

Construction 

Gross State Output, $1,000/plant 151,000 475,000 

Earnings, $1,000/plant 51,000 144,000 

Employment, job-years 455 3,500 

Operation 

Gross State Output, $1,000/year 2,400 10,400 

Earnings, $1,000/year 3,140 2,540 

Employment, jobs 38 56 

Table 5-8 also shows the impact per GWh of power generation for the CSP and 

conventional technologies. This analysis revealed that CSP plant produces higher 

economic benefits per unit of energy produced than either of the conventional 

technologies. The economic impact per unit is similar between the combined cycle and 

simple cycle plants because of the low capacity factor for the simple cycle plant, which 

inflates the economic impacts per unit of energy produced. 

 Figure 5-1 shows the direct and indirect employment impact of the CSP, 

combined cycle, and simple cycle plants per 100 MW. The CSP plant also has a much 

larger impact on employment at about 4,000 job-years per 100 MW versus about 500 for 

the combined cycle plant and 330 for the simple cycle plant. This is a result of the higher 

capital cost and construction requirements of the CSP plant. 

 Figure 5-1 also shows that the CSP plant generates significantly greater economic 

impacts during the operation of the project. There are 94 direct and indirect permanent 

jobs created by the continued operation of the CSP plant, which compares to 56 jobs per 

100 MW created by the combined cycle plant and 13 jobs per 100 MW created by the 

simple cycle plant. Again, this is the result of more labor intensive operational 

requirements of the CSP plant. 

April 21, 2006 5-11 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

Table 5-8 

Total Economic Impacts of One CSP or Conventional Plant in 2008 per 100 MW 

($2005) 

Base Case 

Parabolic 

Trough 

Combined 

Cycle 

Combustion 

Turbine 

Simple Cycle 

Combustion 

Turbine 

Construction 

Gross State Output, $1,000 628,000 64,000 47,000 

Earnings, $1,000 196,000 23,500 17,700 

Employment, job-years 3,990 448 327 

Operation 

Gross State Output, $1,000/year 12,800 10,000 2,000 

Earnings, $1,000/year 5,680 2,700 700 

Employment, jobs 94 56 13 

Operation 

Gross State Output, $1,000/GWh 36 24 23 

Earnings, $1,000/GWh 16 6 8 

Employment, jobs/GWh 0.26 0.16 0.15 

April 21, 2006 5-12 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

-

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

100 MW

Solar

Trough

500 MW

Combined

Cycle

85 MW

Simple

Cycle

100 MW

Solar

Trough

500 MW

Combined

Cycle

85 MW

Simple

Cycle

Construction Employment Impacts, 

Job-Years/100 MW

-

20

40

60

80

100

120

140

160

180

Operation Employment Impacts, 

Jobs/100 MW

Indirect

Direct

Indirect

Direct

CONSTRUCTION OPERATION

Figure 5-1 

Base Case Employment Impact Comparison 

 Black & Veatch also estimated the economic impact of each deployment scenario 

developed for this study. Figure 5-2 shows that the low and high deployment scenarios 

result in total deployment of 2,100 MW and 4,000 MW, respectively. For a complete 

discussion of the deployment schedules refer to Section 4.0. 

-

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Cumulative Installed CSP Capacity, MW

High Deployment

Low Deployment

Figure 5-2 

CSP Low and High Deployment Scenarios 

April 21, 2006 5-13 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

 Table 5-9 shows the total (direct plus indirect) economic impacts of the low and 

high deployment scenarios. The high deployment scenario generates approximately 

double the economic impact of the low deployment scenario, which is expected because 

the high deployment scenario results in about double the installed capacity of the low 

deployment scenario. The results of the economic impacts analysis indicate that a 

significant CSP industry would be formed in California with either large-scale 

deployment scenario. The deployment scenarios would result in about $7 billion and 

$13 billion in investment, respectively, of which an estimated $2.8 and $5.4 billion is 

estimated to be spent in California. This level of in-state investment has a total impact on 

Gross State Product of nearly $13 billion for the low deployment scenario and over 

$24 billion for the high deployment scenario, not including impacts from ongoing O&M 

expenditures. This level of investment creates a sizable direct and indirect impact to 

employment during construction at about 77,000 and 145,000 job-years for the low and 

high deployment scenarios, respectively. Ongoing operation of the CSP plants built 

under the deployment scenarios creates a total annual economic impact of $190 and 

$390 million. 

Table 5-9 

Total Present Value of CSP Development for Two Deployment Scenarios ($2005) 

Low Deployment High Deployment 

Construction 

Gross State Output, $1,000 12,979,000 24,617,000 

Earnings, $1,000 3,556,000 6,649,000 

Employment, job-years 77,300 145,000 

Operation 

Gross State Output, $1,000/year 192,900 390,800 

Earnings, $1,000/year 82,200 164,900 

Employment, jobs 1,500 3,000 

 Assuming that the CSP plants would each operate for 30 years, Figure 5-3 shows 

the total economic impact (direct plus indirect) to earnings and employment in the 

construction and operation periods generated by the deployment scenarios. Figure 5-3 

shows that the earnings and employment impacts are larger for the construction than 

operation periods. The total impacts from operation are significant at about $3.0 billion 

and $5.0 billion to earnings for the low and high deployment scenarios, respectively. 

April 21, 2006 5-14 
NREL 

April 21, 200

Economic Impacts of

CA Solar Benefits CSP in California 

6 5-15 

 The High California Expenditure scenario assumes that more manufacturing 

capability is built in California than the base case assumptions. It is also assumed that 

most of the balance of plant equipment is purchased from in-state suppliers. All 

construction, installation, and most engineering are assumed to be provided by in-state 

suppliers. 

 The Low California Expenditure scenario assumes that less manufacturing 

capability is built in California to support CSP development. This scenario also assumes 

that most of the balance of plant equipment (small pumps, motors, small bore piping, 

etc.) is purchased from out of state suppliers. It is assumed, as with the base case, that 

construction and installation will be provided by in-state suppliers. 

 The assumptions for the amount of material and labor purchased inside and 

outside of California have a significant effect on the direct and indirect economic impacts 

results. Therefore, Black & Veatch developed “Low California Expenditure” and “High 

California Expenditure” scenarios to capture the range of possible economic impacts 

from the construction of CSP plants. Table 5-10 shows the assumptions for material 

purchased from in-state suppliers for the low, base, and high in-state expenditure 

scenarios. 

5.4 Economic Impacts Sensitivity Analysis 

Additionally, the continued operation of the CSP plants results in about 45,000 job-years 

for the low deployment scenario and 80,000 job-years for the high deployment scenario. 

-

1,000

Low High

2,000

3,000

4,000

5,000

6,000

7,000

8,000

Low High

Total Earnings, Million $2005

-

30,000

60,000

90,000

120,000

150,000

180,000

210,000

240,000

Total Employment, Job-Years

EARNINGS EMPLOYMENT

Construction

Operation

Figure 5-3 

Low and High Deployment Scenarios Total Impact to Earnings and Employment 
NREL 

April 21, 200

CA Solar Benefits 

6 

Table 5-10 

Material Expenditures in California Sensitivity Criteria, percent 

2009 CSP Plant 2011 CSP Plant 2

Plant System Low Base High Low Base High Low Siteworks and Infrastructure 0 0 0 0 0 0 0 Contractor Overhead 100 100 100 100 100 100 100 Heat Collection Elements 0 0 0 25 50 75 50 Mirrors 0 0 0 25 50 75 50 Metal Support Structure 25 50 75 25 50 75 25 Misc. Solar Field Equipment 30 59 85 30 59 85 30 HTF System 17 34 61 17 34 61 17 Thermal Energy Storage 23 42 59 40 75 88 40 Thermal Energy Storage Fluid 25 50 75 25 50 75 25 Power Block 2 12 14 2 12 14 2 Balance of Plant 26 50 74 26 50 74 26 Contingency 11 23 35 22 45 67 33 Engineering, Const. Mgmt 25 50 75 25 50 75 25 EPC Markup 30 30 50 30 30 50 30 Land 100 100 100 100 100 100 100 Owners 50 50 50 50 50 50 50 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

 The sensitivity analysis revealed that even with significantly lower purchase of 

equipment and materials from California, the construction of CSP still produces larger 

economic impacts. Figure 5-4 shows the impact to employment and earnings for each 

sensitivity case along with the base case impacts for the combined cycle plant. 

-

1,000

2,000

3,000

4,000

5,000

6,000

Low

California

Expenditures

Base Case High

California

Expenditures

Low

California

Expenditures

Base Case High

California

Expenditures

Construction Employment 

Impacts, Job-Years

-

50

100

150

200

250

Construction Earnings Impact, 

Million $2005

Indirect Direct

Combined 

Cycle

(per 100 MW)

Employment Earnings

Figure 5-4 

Construction Economic Impacts Sensitivity Analysis for 100 MW CSP Plant 

 The sensitivity analysis also revealed that the impact to Gross State Output is 

significantly larger than the comparative combined cycle plant. The CSP plant produced 

a range of $450 million to $800 million compared to $420 million per 100 MW for the 

combined cycle plant. 

 Black & Veatch also developed a sensitivity analysis of the low and high CSP 

deployment scenarios with the low and high California expenditure cases, as shown on 

Figure 5-5. The sensitivity analysis revealed that there is an impact of approximately 

±20 percent to employment and earnings of the low California expenditures and high 

California expenditures scenarios, respectively. The analysis revealed that the impact to 

Gross State Output is slightly higher at about ±30 percent. The sensitivity analysis shows 

that the economic impacts results are robust and consistently higher than the calculated 

impacts for combined cycle power plants even with lower purchases of goods and 

services from California. 

April 21, 2006 5-17 
Economic Impacts of 

NREL CA Solar Benefits CSP in California 

-

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

200,000

Low

California

Expenditures

Base Case High

California

Expenditures

Low

California

Expenditures

Base Case High

California

Expenditures

Construction Employment 

Impacts, Job-Years

-

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

Construction Earnings Impacts, 

Million $2005

Low

High

Figure 5-5 

Construction Economic Impacts Sensitivity Analysis of 

Low and High CSP Deployment Scenarios 

5.5 Fiscal Impacts 

 Black & Veatch developed preliminary estimates of the fiscal impact (tax 

revenues) associated with the construction and continued operation of the CSP plants 

under the low and high deployment scenarios. To provide a point of comparison, the 

fiscal impacts for 2,100 and 4,000 MW of combined cycle power generation were also 

estimated. Fiscal impacts include the sales taxes during construction, individual income 

taxes paid by construction workers, individual income taxes paid by indirect jobs created 

by construction, individual income taxes paid by operators, individual income taxes paid 

by indirect jobs created during operation, and corporate income taxes assuming IPP 

ownership of the project. Based on data from the Tax Foundation, an individual state and 

local tax rate of 8.7 percent and a corporate state income tax rate of 8.84 percent have 

been assumed. The analysis yielded potential tax revenues of $1.3 billion for the low 

deployment scenario and $2.4 billion for the high deployment scenario, both in 2005 

dollars. The potential fiscal impacts of constructing and operating 2,100 MW and 

4,000 MW of combined cycle power plants are about $300 million and $600 million, 

respectively. The larger fiscal impacts for the CSP plants are a result of the larger capital 

cost and more labor intensive operations and maintenance of the CSP plants. 

These fiscal impacts estimates are approximate and could vary significantly based 

on a number of factors including economic life of the CSP plants (assumed to be 30 years 

for this analysis), local tax abatements, changes to tax laws, corporate structure of the 

plant owner, and other factors. 

April 21, 2006 5-18 
Cost of Energy and 

NREL CA Solar Benefits Value of Dispatchability 

6.0 Cost and Value of CSP Energy 

 This section provides the results of cost of energy calculations for CSP along with 

an evaluation of the time of delivery value of CSP energy. This section begins with a 

discussion of the Market Price Referent, the “reference price” of energy in California. 

6.1 The Market Price Referent 

 A good starting point for discussion of the cost of renewable energy in California 

is the Market Price Referent, or MPR.10 The MPR is part of the rulemaking surrounding 

the California Renewable Portfolio Standard (RPS). Utilities in California are not 

obligated to purchase renewable energy at prices above the MPR, which is a value set by 

the California Public Utilities Commission (CPUC) to reflect the market “all-in” (energy 

and capacity) price for base-load energy. If a renewable energy project has a cost to 

generate above the MPR, the generator can apply to the CEC for Supplemental Energy 

Payments (SEPs) to cover above market costs. The MPR is released after the results of 

the renewable energy solicitations are announced so the MPR does not affect the bids. 

The MPR for 2005 was calculated with a proxy plant methodology using a natural 

gas fired combined cycle plant as the proxy for base-load energy. There was no simplecycle proxy as in previous years. Instead, time of delivery (TOD) multipliers are to be 

applied to the baseload MPR value to come up with pricing at peak times. The all-in 

dollar per MWh levelized energy price for each proxy plant was calculated for 10, 15, 

and 20 year contract terms. The 2005 MPR value for a 20-year PPA starting in 2007 is 

$77.24 per MWh. The MPR also includes a 25-year natural gas price forecast, which is 

based on NYMEX forward futures costs for the first six years, and a combination of EIA 

and private forecasts for the later years. This report uses a natural gas forecast of $6.40 

per MMBtu, escalated at 2.5 percent, which is equivalent to the levelized MPR natural 

gas forecast for 2007-2026.11 The CPUC MPR gas forecast is the consensus forecast of 

California natural gas prices among the CPUC, Utilities, and public interest groups. 

 

10 The 2005 MPR declaration was published in March 2006 by the CPUC. It is available at 

http://www.cpuc.ca.gov/PUBLISHED/COMMENT_RESOLUTION/54445.htm. 11 Levelized using the MPR weighted average cost of capital of 9.3 percent as the discount rate. The 

levelized forecast for MPR natural gas from 2007 to 2026 is $7.61/MMBtu, while $6.40/MMBtu escalated 

at 2.5 percent annually is $7.62/MMBtu levelized. 

April 21, 2006 6-1 
Cost of Energy and 

NREL CA Solar Benefits Value of Dispatchability 

The MPR also included other assumptions about plant heat rates, debt/equity 

splits, and finance costs. Where possible, this report has used the same assumptions as 

the MPR.12

6.2 Cost of Energy Calculations 

Black & Veatch developed a cost of energy comparison between each of the proxy 

parabolic trough CSP plant and comparable fossil fuel technologies. The levelized cost 

of energy is a present value measure of the lifecycle cost of generating power from a 

given plant considering the capital cost, operating costs (including fuel), capacity factor, 

financing cost, and incentives. The levelized cost is a useful calculation because it allows 

comparison of different generation technologies on an equal basis. For this analysis, the 

parabolic trough CSP plant was compared with simple cycle and combined cycle 

combustion turbines because these types of plants provide peaking and intermediate 

electric services similar to CSP plants. Capital cost and performance assumptions for the 

CSP technologies were developed in Section 2.0 and performance assumptions for the 

combined and simple cycle combustion turbines were provided in Table 5-3. Financial 

assumptions, such as cost of debt and equity, were taken directly from the 2005 MPR 

ruling and are listed in Table 6-1. Actual plant financing parameters may differ from 

MPR; however, MPR has been used in this document for consistency. For all generation 

technologies it was assumed that the plant would be owned by a credit worthy 

independent power producer (IPP) with a power purchase agreement with a California 

IOU. 

The Energy Policy Act of 2005 contains a number of incentives for renewable 

energy generation13. Specifically, the Act increases the Investment Tax Credit (ITC) to 

30 percent through December 31, 2007, for solar facilities14. Solar facilities had a 

“permanent” ITC of 10 percent before the Act was passed. Because the 30 percent ITC 

may not be extended, cost of energy calculations have been made assuming both a 

30 percent ITC and the older 10 percent ITC.15

 

12 We diverge only in capacity factor. The MPR uses a 92 percent capacity factor, while we use 40 percent 

to stay consistent with the intermediate duty cycle of CSP. At a 92 percent capacity factor, our LCOE 

calculations result in a price of $77 per MWh, equivalent to the MPR. 

13 26 USC § 48 (2005). 

14 The Act also extended the Production Tax Credit (PTC) to solar facilities, but the PTC for solar expired 

at the end of 2005. 

15 A bill was recently introduced in the Senate (S.2401) that would extend the ITC to 2010. 

April 21, 2006 6-2 
Cost of Energy and 

NREL CA Solar Benefits Value of Dispatchability 

April 21, 2006 6-3 

Table 6-1 

Financial Assumptions for Cost of Energy Calculations 

Assumption 

Combustion 

Turbine CSP Plants 

Economic Life, years 30 30 

Tax Life, years 20 5 

Debt Percentage 42.5% 42.5% 

Cost of Debt 8.0% 8.0% 

Cost of Equity 12.7% 12.7% 

Weighted Average Cost of Capital (WACC) 

(Used as discount rate) 9.3% 9.3% 

Tax Rate, combined federal and state 40.75% 40.75% 

Levelized Fixed Charge Rate 14.4% 11.8% 

Investment Tax Credit N/A 30% and 10% 

2007 Natural Gas Price (escalated at 2.5% 

annually) $6.40/MMBtu N/A 

2015 Natural Gas Price (escalated at 2.5% 

annually) $8.00/MMBtu N/A 

Inflation Rate 2.5% 2.5% 

Real Discount Rate 6.8% 6.8% 

Note: 

All assumptions from the 2005 California Market Price Referent financial inputs. 

Real and nominal levelized cost estimates for parabolic trough CSP plants and the 

conventional alternatives are provided in Table 6-2. The levelized costs of developing a 

CSP plant in 2007, 2009, 2011, and 2015 include the effects of the learning curves, which 

reduce the capital cost over time with increased deployment. The characteristics of the 

plants developed in 2009, 2011, and 2015 were used to calculate the economic impact of 

developing CSP plants in Section 5.0. The CSP plants have nominal levelized costs in 

the range of $103 per MWh to $157 per MWh with the 30 percent ITC and $115 per 

MWh to $176 per MWh with the permanent 10 percent ITC. This is competitive with the 

2007 simple cycle combustion turbine with a levelized cost of $168 per MWh (using the 

MPR natural gas price of $6.40/MMBtu escalated at 2.5 percent). However, the plants 

have different capacity factors; the simple cycle plant provides peaking service with a 
NREL 

April 21, 200

CA Solar Benefits Cost of Energy and V

6 

Table 6-2 

Levelized Cost Comparison* 

Capacity, 

MW 

Storage, 

hours 

Capacity 

Factor, % 

Nominal 

Levelized 

Cost, $ per 

MWh 

(30% ITC) 

Nominal 

Levelized 

Cost, $ per 

MWh 

(10% ITC) 

Rea

Leveli

Cost, $ 

MW

(30% I

Simple Cycle 85 N/A 10.0 168 168 134 Simple Cycle ($8/MMBtu Gas)** 85 N/A 10.0 187 187 149 Combined Cycle 500 N/A 40.0 104 104 83 Combined Cycle ($8/MMBtu Gas)** 100 N/A 40 119 119 95 Parabolic Trough (2007) 100 0 28.4 154 173 125 Parabolic Trough (2007) 100 6 40.4 157 176 127 Parabolic Trough (2009) 100 6 40.4 148 166 120 Parabolic Trough (2011) 150 6 40.4 120 134 97 Parabolic Trough (2015) 200 6 40.4 103 115 83 *Financial assumptions are essentially per MPR calculation methodology. Assumptions are provided in Table 6-1. **$8/MMBtu is MPR gas price for 2015. 
Cost of Energy and 

NREL CA Solar Benefits Value of Dispatchability 

10 percent capacity factor and the trough plant with storage provides intermediate service 

with a 40 percent capacity factor. 

The CSP plants are not competitive with the combined cycle plant in the early 

years, but become more so in the 2015 timeframe. At a levelized gas price of $8/MMBtu, 

which is the MPR forecast for 2015, the combined cycle plant, at a capacity factor of 

40 percent, has a levelized cost of $119/MWh. This is roughly equivalent to the 

$115/MWh of the CSP plant in 2015, with the permanent 10 percent ITC. 

6.3 The Time of Delivery Value of CSP Energy 

 This section discusses the value provided by thermal storage integrated with the 

proxy parabolic trough CSP plant. Conceptually, thermal storage allows the plant to store 

energy generated during lower power demand periods and deliver this energy during 

high-demand hours (see Figure 6-1). Thermal storage, along with an enlarged solar field, 

also allows the CSP plant to operate at a higher annual capacity factor, about 40 percent 

with 6 hours of storage versus 28 percent for no storage. This gives the plant the ability 

to generate higher revenues to off-set the additional cost of the storage system. The 

levelized costs in Table 6-2 reveal this, as the trough plant with 6 hours of storage and 

without storage have roughly the same cost of energy ($157/MWh vs. $154/MWh). 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

H our of D ay

Plant Output

From Storage

To S torage

D irect S olar

Figure 6-1 

Conceptual Generation Scenario with Storage 

April 21, 2006 6-5 
Cost of Energy and 

NREL CA Solar Benefits Value of Dispatchability 

 Renewable energy generators generally fall into two categories: firm and asavailable. As-available resources are resources such as wind or CSP without storage that 

are not controlled by the generator, while firm resources can control when they generate. 

PG&E lists four energy “products” allowed to bid into their 2005 renewable RFO: asavailable, baseload, peaking, and dispatchable. Peaking resources must have at least a 

95 percent capacity factor during the peak summer hours16, while baseload resources 

have 24x7 profiles. Dispatchable resources must be available on a day-ahead schedule. 

The trend in the renewable energy industry is toward a single all-in energy 

payment, with no separate capacity payments.17. In the past, firm resources would 

receive capacity payments as well as energy payments. The lack of capacity payments 

makes it more difficult to assign a dollar value to a firm resource versus an as available 

resource, especially if both of those resources have similar time of delivery (TOD) 

profiles. The MPR methodology for assigning value to energy is based on the generator’s 

TOD profile, with multipliers for various time periods. For example, a plant that ran only 

during peak hours would have an MPR price of $110/MWh, based on SCE’s TOD factor 

of 1.425 applied to the 2007 MPR ($77.24/MWh) 

The MPR prices for a CSP plant with 6 hours of storage and a CSP plant without 

storage were determined by applying the TOD multipliers to Excelergy’s production 

profile. Surprisingly, both CSP plants have approximately the same MPR energy value of 

about $87/MWh.18 Examination of the generation profile data show that, while the plant 

with storage generates more higher-value energy during peak hours, it also generates 

more lesser-value energy during non-peak hours. Although there is no separate capacity 

credit that can be assigned to the CSP plant with storage, it clearly has more value to the 

utility than an “as available” CSP plant without storage, despite their similar MPR prices. 

The plant with storage qualifies as a firm “peaking” resource under PG&E’s rules,19

generating firm power during peak summer hours. PG&E explicitly states a preference 

for peaking resources in its 2005 RFO, as it rates peaking resources as a “high” need and 

as-available as a “low.” Future MPR methodologies may return to including assigning 

explicit capacity value, which allow solar thermal with storage to receive a more explicit 

capacity credit. 

 

16 Noon to 8PM, PDT, June through September. 

17 PG&E, SCE, SDG&E, SMUD and LADWP all have a single all-in payment structure for renewable 

energy, and the MPR no longer contains a peaking unit. Other IOUs are also moving to all-in payments. 

18 This value is using the 2005 MPR and SCE's TOD multipliers. PG&E’s and SDG&E’s multipliers are 

similar. 

19 Excelergy modeling shows that 6 hours of storage is needed to ensure 95 percent availability during peak 

times. 

April 21, 2006 6-6 
NREL CA Solar Benefits Environmental and Hedging Benefits 

7.0 Environmental and Hedging Benefits 

 CSP plants provide environmental benefits by generating power without 

producing criteria and CO2 air emissions. In addition, the use of fixed cost renewable 

energy generation, such as CSP or wind, can decrease fossil fuel use and provide a hedge 

against fossil fuel price increases. While CSP plants may have environmental benefits 

due to emissions reductions, they do require significant land area. A 100 MW CSP plant 

is estimated to cover approximately 800 acres (comprised mostly of the solar field) while 

a 500 MW combined cycle plant would occupy about 20 acres.20 

7.1 Reduction in Criteria and CO2 Air Emissions 

 A key benefit of the use of CSP plants in California is the potential to reduce the 

amount of criteria and greenhouse gas emissions. The installation of CSP may reduce air 

emissions if generating power from CSP plants offsets generation from fossil fueled 

plants.21 For this calculation of emissions reductions, it has been assumed that the CSP 

plants will displace generation by combined cycle plants with an average heat rate of 

7,000 Btu/kWh. Typical permitted emissions requirements for a new plant in southern 

California were obtained from the California Air Resources Board, and are shown in 

Table 7-1.22 Based on these emission rates, the table also shows the amount of emissions 

displaced by annual generation from a single 100 MW trough plant with six hours of 

storage, as well as for the low deployment and high deployment scenarios of 2,100 MW 

and 4,000 MW of CSP generation capacities, respectively. 

The estimates in Table 7-1 are conservative because of the assumption that CSP 

would displace emissions from new plants. CSP plants could offset generation from 

older thermal natural gas or oil fueled generation with average heat rates equal to or 

exceeding 10,000 Btu per kWh, which would increase the emissions offset by about 

30 percent. Furthermore, the older plants are unlikely to have modern air emissions 

control technology that would be required on new plants. Thus, the increase in emissions 

offset by assuming displacement of older generation would likely exceed 30 percent. 

 

20 Of course, the land requirements for the combined cycle plant do not include the land required for 

acquisition of natural gas. 

21 While emissions reduction can be more complicated when cap-and-trade systems (such as the RECLAIM 

system for NOx trading in the South Coast Air Quality Management District) are involved, it is generally 

correct to assert that a CSP plant that offsets a natural gas-fired plant will result in less emissions. 

22 Permitted air emissions requirements are available at the California Air Resources Board at: 

www.arb.ca.gov/bact/bactnew/rptpara.htm 

April 21, 2006 7-1 
NREL CA Solar Benefits Environmental and Hedging Benefits 

Table 7-1 

Emissions Reduction by CSP Plants 

Proxy Fossil Plant 

Emissions Rate CSP Plant Capacity 

Pollutant lb/MMBtu 

Parts per 

million 

100 MW 

(tons/year) 

2,100 MW 

(tons/year) 

4,000 MW 

(tons/year) 

NOx 0.006 2 7.4 156 297 

CO 0.004 4 4.5 95 181 

VOC 0.002 1.4 2.6 54 103 

CO2 154 191,000 4,000,000 7,600,000 

Notes: 

1. Proxy Fossil Plant assumed to be a combined cycle combustion turbine with a heat rate of 

7,000 Btu/kWh. 

2. CSP plants assumed to operate at 40 percent capacity factor. 

7.2 Hedging Impact of CSP on Natural Gas Prices 

 The installation of renewable energy power generation that does not use fossil 

fuels has the potential to provide a natural hedge against fossil fuel price increases. 

Generally, renewable energy generators, particularly CSP that serves peak demand, offset 

the use of natural gas fueled generators. Therefore, this section focuses on the analysis of 

CSP as a hedge against natural gas price increases. An overview of the consumption and 

price of natural gas in the US and California is provided first. The two primary hedging 

effects are then analyzed: the potential decline in prices and volatility from decreased 

demand, and the hedging effect that the installation of CSP has on the generation 

portfolio. 

7.2.1 Natural Gas Use in the United States 

 Natural gas is a primary fuel for the US residential, commercial, industrial, and 

power generation sectors. Figure 7-1 shows the growth in overall natural gas demand 

since 1990. Gas consumption for power generation is a major part of the growth, 

accounting for 5,721 trillion Btu (TBtu) in 2002 compared with 3,342 TBtu in 1990, a 70 

percent increase. Demand growth is expected in all sectors, but demand from electricity 

generators is expected to grow the fastest, increasing 90 percent by 2025. Various reports 

project demand to increase to 28 to 31 TCF per year by 2025. 

April 21, 2006 7-2 
NREL CA Solar Benefits Environmental and Hedging Benefits 

Figure 7-1 

Historic and Forecast Natural Gas Demand by Sector (NPC 2002) 

Source: American Gas Association 

Natural gas consumption for power generation has increased because the 

development of relatively low cost, high-efficiency combined cycle combustion turbine 

technology has made natural gas an economic alternative to oil and coal. Furthermore, 

gas is the cleanest burning of the fossil fuels and is favored globally for its relatively low 

greenhouse gas emissions when compared with other fossil fuels. Figure 7-2 shows that 

new electric generating capacity installed in the US for 1990-2006 was primarily natural 

gas fueled. Despite the large increase in natural gas fueled power generation, coal still 

provides about 50 percent of the electric supply for the US, followed by nuclear at about 

20 percent, and natural gas fueled power stations at about 18 percent.23

7.2.2 Natural Gas Use in California 

California currently consumes about 10 percent of the total natural gas used in the 

US – about 2.36 TCF in 2004. It is estimated that in the next decade, California will add 

five million people to its current population of about 35 million. The added population 

will need power and fuel; three-quarters of California’s electricity growth and most of the 

state’s natural gas growth will be driven by the need to serve these new citizens. 

 California is particularly vulnerable to natural gas price fluctuations and supply 

constraints because of its reliance on out-of-state sources. Currently, about 85 percent of 

the consumption is provided by imports. Figure 7-3 shows a breakdown of the source of 

natural gas for the California market. 

 

23 For 2004, EIA 

35 2%/YEAR GROWTH 1%/YEAR GROWTH 

30 Canada 

25 US Power 

20 US Cogeneration TCF 

15 US Industrial 

10 

US Residential/Commercial 

5

Other 

0

1990 1995 2000 2005 2010 2015 2020 2025 

April 21, 2006 7-3 
NREL CA Solar Benefits Environmental and Hedging Benefits 

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

19901992199319951996199819992000200120022003200420052006

Water

Renew

Petro

Other

Nuc

Gas

Coal

Figure 7-2 

Breakdown of US Capacity Additions by On-Line Date (MW) 

Source: US Department of Energy, Energy Information Administration 

Southwest 

36.2 %

In State 

15.5 %

Canada 

24 %

Rockies

24.3 %

Figure 7-3 

California’s Natural Gas Sources for 2004 

Source: California Energy Commission 

April 21, 2006 7-4 
NREL CA Solar Benefits Environmental and Hedging Benefits 

 The California Energy Commission (CEC) has passed a moratorium on the 

construction of coal fueled power generation in the state and the import of power 

produced by coal fueled plants. By removing coal as a possible fuel for new power 

generation, natural gas fueled or renewable energy will be required to meet the growing 

demand for power in the state. 

7.2.3 Natural Gas Prices and Price Volatility 

 Natural gas is actively traded on commodities markets throughout the world, such 

as the New York Mercantile Exchange (NYMEX) or the Chicago Board of Trade 

(CBOT). The fuel is bought and sold for immediate delivery, the “spot market,” and 

options on future delivery (“futures contracts”) are traded. Long-term price trends are 

typically caused by factors that affect supply and demand, such as economic activity and 

changes to natural gas production and storage. Figure 7-4 shows an upward long-term 

trend of natural gas prices in California. The figure also shows the impact of short-term 

phenomena on natural gas prices. The chart also shows the short-term effect of 

supply/demand shock during the California energy crisis in 2000 and 2001. The surge in 

the use of natural gas to meet power demand created short-term supply constraints and, 

thus the price spikes shown in the chart. 

2.23 2.71 3.08 2.79 2.76

5.88

9.40

3.82

5.49

6.05

7.76

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

$ per Mcf

 

Figure 7-4 

California Electric Power Sector, Annual Average Natural Gas Prices, $ per MCF 

(Source: EIA24) 

 

24 2005 data point is for Jan-Nov, as Dec had not been reported as of 4/6/2006. 

April 21, 2006 7-5 
NREL CA Solar Benefits Environmental and Hedging Benefits 

 Short-term market price fluctuations, or volatility, are caused by random factors 

such as weather, expectations of future supply, geopolitical events, etc. The ability of the 

market to absorb short-term supply shocks caused by these factors is directly impacted by 

the relationship of supply and demand in the market. For example, a relatively small 

change in price would be expected if a short-term supply shock occurred and supply 

significantly exceeded demand. However, a relatively large price impact could be 

expected if supply and demand were in balance. The US is currently in the latter 

situation. While demand has increased, production has been relatively constant. 

A combination of long-term and short-term factors has led to a consistent and 

significant increase in natural gas prices in recent years. The average wellhead natural 

gas price rose from around $2 per MMBtu in the 1990s to $7.51 per MMBtu in 2004.25 

The 6 year NYMEX forward curve indicates that the price at the Henry Hub will remain 

in the $5 to $8 per MMBtu range, while the EIA’s latest forecast26 projects that wellhead 

prices will average $5 MMBtu in the coming 20 years. 

7.2.4 The Hedging Impact of CSP Deployment in California 

 There are two basic benefits that the large scale deployment of CSP could provide 

to the California natural gas and electric markets: reduction of natural gas prices from 

decreased demand; and lower exposure to natural gas price fluctuations from a more 

diversified electric generating portfolio. This section includes a brief analysis of each of 

these potential impacts and a high-level estimate of the potential value of these impacts. 

7.2.4.1 Impact on Natural Gas Prices. The deployment of non-fossil fueled power 

generation can decrease or slow the growth in demand for fossil fuels if power generated 

by fossil fueled plants is off-set by renewable energy generators. Several recent studies 

suggest that there could be a price decrease of between one and four percent for each 

1 percent decline in demand.27,28 Therefore, based on a 1 percent reduction in gas price 

for a 1 percent reduction in nationwide gas usage, the deployment of 4,000 MW of CSP 

in California could result in a total reduction of approximately $60 million per year for 

 

25 US Energy Information Administration (EIA) www.eia.doe.gov. 26 2006 Annual Energy Outlook. Released December 2005. www.eia.doe.gov. 27 Easing the Natural Gas Crisis: Reducing Natural Gas Prices through Inceased Deployment of 

Renewable Energy and Energy Efficiency Ryan Wiser, Mark Bolinger, Matt St. Clair., Berkley National 

Laboratory, LBNL-56756, January 2005. 

28 Dr. Ryan Wiser, Scientist, Lawrence Berkeley National Laboratory, testimony to Senate Committee on 

Energy and Natural Resources, Easing the Natural Gas Crisis: Reducing Natural Gas Prices Through 

Electricity Supply Diversification, March 8, 2005. 

April 21, 2006 7-6 
NREL CA Solar Benefits Environmental and Hedging Benefits 

natural gas expenditures in California, assuming a natural gas price of $6.40 per 

MMBtu.29 If the natural gas price reduction were to be in the range of 4 percent for each 

1 percent reduction in nationwide gas usage, the savings in gas cost to California could be 

four times higher. These savings in California are based on average savings for US 

consumers. However, savings per MMBtu could be higher in California than the national 

average. Dr. Ryan Wiser, in private communication, wrote, “Though reductions in 

California natural gas demand will have national price impacts that spill over to the state, 

the impact on California natural gas prices may be somewhat higher than the national 

impact if the natural gas transportation infrastructure serving California is constrained.30” 

7.2.4.2 Portfolio Hedging Impact. Electricity is provided to California consumers 

primarily by natural gas, imported coal fueled power, and hydroelectric energy. 

Figure 7-5 shows the source of electricity generation in California. 

Large Hydro

14.8 %

DSW Imports 

12.75 %

Renewables

10.6 %

PNW Imports

 6.33 %

Nuclear 

12.9 %

Coal * 

19.8 %

Natural Gas 

41.9 %

Figure 7-5 

Generation Sources for California Electricity in 2004 

Source: California Energy Commission 

*Intermountain and Mohave coal plants are considered in-state, since they are in California 

control areas. 

 

29 Taking the US gas consumption in 2004 to be 23,000 trillion Btu, and assuming a proxy of a combined 

cycle plant heat rate of 7,000 Btu/kWh, the amount of natural gas displaced by a 100 MW CSP plant 

operating at a 40 percent capacity factor is 2,400 billion Btu/yr, or 0.01 percent of the US gas consumption. 

Likewise, the amounts of natural gas displaced by 2,100 MW and 4,000 MW are 52,000 billion Btu/yr and 

99,000 billion Btu/yr, (0.2 percent and 0.4 percent of national consumption), respectively. At 1 percent 

price reduction for each one percent of demand reduction, this would equate to a 0.01 percent price 

reduction resulting from a 100 MW plant, a 0.2 percent price reduction for a 2,100 MW CSP deployment, 

and a 0.4 percent price reduction for a 4,000 MW CSP deployment. 

30 Dr. Ryan Wiser in an email to Dr. Larry Stoddard, Black & Veatch, December 13, 2005. 

April 21, 2006 7-7 
NREL CA Solar Benefits Environmental and Hedging Benefits 

Natural gas fueled power generation provides the largest share of electricity in 

California - over 40 percent. The natural gas fueled generation fleet consists of older 

steam thermal electric units, combined cycle combustion turbines, and simple cycle 

combustion turbines. Depending upon which utilities purchase the output from new CSP 

plants, the deployment of CSP could off-set the construction of new combined cycle and 

simple cycle plants or the use of older less-efficient steam thermal units. 

Hydroelectricity is also an important element of California’s energy portfolio. 

Between 1983 and 2002, in-state hydropower provided an annual average of 

approximately 37,000 GWh, or 15 percent, of the electricity used in California. During 

this same period, hydroelectric generation ranged from 9 percent to 30 percent of total 

state electricity sales, depending on hydrologic conditions. Hydropower’s important 

energy attributes include peaking reserve capacity, spinning reserve capacity, load 

following capacity, transmission support, and extremely low production costs. 

Due to the seasonal and annual variation in hydrologic cycles, hydroelectric 

production varies widely from year to year. Figure 7-6 shows the annual variation in 

capacity factor for hydroelectric plants in the US. When precipitation runoff is bountiful, 

hydroelectric generation is used and other generating plants, mostly gas-fired facilities, 

are idled. When hydroelectric energy generation is low, intermediate and peaking 

generating plants make up the difference. 

0%

10%

20%

30%

40%

50%

60%

70%

80%

1998 1999 2000 2001 2002

Biomass

Geothermal

Hydro

Wind

Solar

Source: EIA, REA 200

Figure 7-6 

Annual Variation in Renewable Energy Project Capacity Factors 

Source: EIA, REA 2002 

April 21, 2006 7-8 
NREL CA Solar Benefits Environmental and Hedging Benefits 

A diversified portfolio of generation technologies and energy sources decreases 

the total risk of the portfolio to fluctuations in the value of any one component of the 

portfolio. Black & Veatch estimated the relative portfolio hedging effect of CSP to the 

California electric system based upon plant production cost data obtained from Platt’s and 

the CSP deployment scenarios developed in Section 4.0.31 The total annual production 

cost, that is, fuel plus non-fuel variable O&M cost, but not including capital costs, was 

calculated for the current California generation portfolio, the low CSP deployment and 

high CSP deployment scenarios. This calculation was then repeated for three natural gas 

price scenarios. Figure 7-7 provides the total annual production cost compared to the 

base case generation portfolio. As shown in Figure 7-7, the total cost increases by 

32 percent for the base case portfolio and by 27 percent under the high CSP deployment 

scenario – a difference of 5 percentage points. Given a total annual production cost of 

about $12 billion under the high fuel scenario, this difference equates to about 

$500 million annually. The benefit is somewhat smaller for the low CSP deployment 

scenario, but still positive. Thus, the benefit of portfolio diversification can be significant 

depending on the volatility of the other components of the portfolio. 

70

80

90

100

110

120

130

140

5 7 10 

Natural Gas Price, $/MMBTU

Total Annual Production Cost -

Percent of Current Generation Portfolio 

Current Generation Portfolio

Low CSP Deployment

High CSP Deployment

Figure 7-7 

Effect of CSP Deployment on Statewide Generation Cost (Current Portfolio with 

$7.00/MMBtu gas = 100) 

 

31 Plant production cost data by fuel type provided by Platt’s and available through the Platt’s Power 

Outlook Research Service at: www.platts.com. 

April 21, 2006 7-9 
NREL CA Solar Benefits Conclusions 

8.0 Conclusions 

 The purpose of this study was to determine the economic and environmental 

impacts on California resulting from the installation of concentrating solar power plants. 

The primary focus was on economic and employment impacts and the comparison of 

these findings with the corresponding impacts from conventional gas fired generators that 

would otherwise be employed. To ensure that projected installation scenarios were 

realistic, the electricity supply characteristics of potential CSP technology variants were 

examined and the availability of California solar resources to support estimated solar 

plant output was addressed. The environmental impacts of power production were 

quantified as well as the possible “hedge” value against increases in natural gas price. 

Having completed the foregoing, Black and Veatch reaches the following conclusions: 

• California has high quality solar resources sufficient to support far more 

concentrating solar installations than either of the 2,100 MW or 

4,000 MW capacity scenarios postulated for this study. 

• Depending on the CSP plant interconnection point and the load profile of 

the local electricity provider, concentrating solar power installations with 

6 hours storage could perform peaking and/or intermediate generation 

roles for the utility. 

• Investment in CSP power plants delivers greater return to California in 

both economic activity and employment than corresponding investment in 

natural gas equipment: 

- Each dollar spent on CSP contributes approximately $1.40 - $1.50 

to California’s Gross State Product; each dollar spent on natural 

gas plants contributes $0.90 - $1.00 to Gross State Product. 

- The 4,000 MW deployment scenario was estimated to create about 

3,000 permanent jobs from the ongoing operation of the plants. 

• Operational period expenditures on operations and maintenance create 

more permanent jobs than alternative natural gas fueled generation. 

• For each 100 MW of generating capacity, CSP was estimated to generate 

94 permanent jobs compared to 56 jobs and 13 jobs for combined cycle 

and simple cycle plants, respectively. 

• Energy delivered from early CSP plants (startup in 2007) costs more than 

that delivered from natural gas combined cycle plants32 ($157 per MWh 

 

32 Based on MPR gas prices for 2007, $6.40/MMBtu, and assuming a 100 MW CSP plant with 6 hours 

storage and a 500 MW combined cycle plant. Both CSP and combined cycle plants operate at 40 percent 

capacity factor. All dollars are $2005. 

April 21, 2006 8-1 
NREL CA Solar Benefits Conclusions 

vs. $104 per MWh, based on a 30 percent ITC for CSP). With technology 

advancements, improvements to CSP construction efficiency, and with 

higher gas prices consistent with 2015 MPR projections, CSP becomes 

competitive with combined cycle power generation ($115 per MWh vs. 

$119 per MWh, even with the permanent 10 percent ITC). Most of the 

economic and employment advantages are still retained. 

• CSP plants are a fixed-cost generation resource and offer a physical hedge 

against the fluctuating cost of electricity produced with natural gas. 

• Each CSP plant provides emissions reductions compared to its natural gas 

counterpart; the 4,000 MW scenario in this study offsets at least 300 tons 

per year of NOx emissions, 180 tons of CO emissions per year, and 

7,600,000 tons per year of CO2. 

 The economic and employment benefits, together with delivered energy price 

stability and environmental advantages, suggest that the CSP solar alternative would be a 

beneficial addition to California’s energy supply. While early CSP plants are more costly 

than their traditional gas counterparts, subsequent plants are estimated to become nearly 

cost competitive on a levelized cost of energy basis. 

April 21, 2006 8-2 
NREL CA Solar Benefits Appendix A 

Appendix A 

Technology Assessment 

April 21, 2006 A-1 
NREL CA Solar Benefits Appendix A 

Appendix A 

Technology Assessment 

 This CSP technology assessment was aimed at characterizing the CSP 

technologies for the economic impact assessment tasks. Performance, commercial 

readiness, cost, reliability, and technical risk have been characterized. Six technologies 

are discussed in this section. 

• Parabolic trough without storage or hybrid fossil. 

• Parabolic trough with storage. 

• Parabolic trough with hybrid fossil. 

• Parabolic dish. 

• Power tower. 

• Concentrating photovoltaic (CPV). 

 Concentrating solar thermal power plants produce electric power by converting 

the sun’s energy into high temperature heat using various mirror or lens configurations. 

For solar thermal systems (trough, dish-Stirling, power tower), the heat is transferred to a 

turbine or engine for power generation. Thermal plants consist of two major subsystems: 

one that collects solar energy and converts it to heat, and another that converts heat 

energy to electricity. CPV plants provide power by focusing solar radiation onto a 

photovoltaic (PV) module, which converts the radiation directly to electricity. Either 

mirrors or lenses can be used to concentrate the solar energy for a CPV system. 

 All CSP systems make use of the direct normal component of solar radiation, that 

is, the radiation that comes directly from the sun. Concentrating systems are unable to 

use global radiation, which is reflected radiation. Global radiation is present on sunny 

days and on cloudy days. Direct normal insolation (DNI) is available only on sunny 

days. Concentration of DNI allows a solar system to achieve a high working fluid 

temperature, or, in the case of CPV, allows expenditure for higher efficiency CPV cells 

since the cell area is small compared with the collector (mirror or lens) area. The need to 

focus DNI requires that collector systems track the sun. Parabolic trough systems use 

single-axis trackers to focus radiation onto a linear receiver. Dish-Stirling and power 

tower systems use two-axis trackers. The CPV systems discussed in this report use two 

axis tracking to achieve point focus images on PV cells. Single axis, line focus CPV 

systems have been built, but do not appear to have the long term commercial potential 

that the two axis tracking CPV systems have. 

April 21, 2006 A-2 
NREL CA Solar Benefits Appendix A 

 Because trough and power tower systems collect heat to drive central turbinegenerators, they are best suited for relatively large plants—50 MW or larger. Dish and 

CPV are modular in nature, with single units producing power in the range of 10 kW to 

35 kW. Thus, dish and CPV systems could be used for distributed or remote generation 

applications, and can be sited as large plants by aggregating many units. Trough and 

tower plants, with their large central turbine generators and balance of plant equipment, 

have a cost advantage of economy of scale—that is, cost per kW goes down with 

increased size. Dish and CPV systems have the potential advantage of mass production 

of individual units, similar to the mass production of automobiles 

 Trough and tower systems have the potential advantage over dish and CPV 

systems in that an amount of dispatchability can be designed into the system with thermal 

storage or the use of hybrid fossil. Dispatchability allows the solar plant to generate 

electricity during short duration cloudy periods or to generate electricity into the evening 

after sunset. This gives the plant potential to receive capacity credit, and provides the 

ability to more closely match the utility peak load profile. At this time, dish-Stirling 

systems have not been configured to provide hybrid fossil capability. CPV systems 

could, of course, make use of battery energy storage; however, battery storage is 

comparatively inefficient and expensive, and has not been considered in this study. 

Should battery storage system costs decrease substantially, and efficiency increase, the 

use of storage with CPV would certainly be an option in the future. 

A.1 Parabolic Trough Systems 

 Parabolic trough systems concentrate DNI using single axis tracking, parabolic 

curved, trough-shaped reflectors onto a receiver pipe or heat collection element (HCE) 

located at the focal line of the parabolic surface. A high temperature heat transfer fluid 

(HTF) picks up the thermal energy in the HCE. Heat in the HCE is used to make steam 

in the steam generator. The steam drives a conventional steam-Rankine power cycle to 

generate electricity. Figure A-1 shows a row of trough collectors. A collector field 

contains many parallel rows of troughs connected in series. Rows are typically placed on 

a north-south axis, allowing the single-axis troughs to track the sun from east to west 

during the day. 

 

April 21, 2006 A-3 
NREL CA Solar Benefits Appendix A 

Figure A-1 

Photo of Parabolic Trough System 

(Source: NREL) 

A.1.1 SEGS Plants 

 The largest collection of parabolic systems in the world is the Solar Energy 

Generating Systems (SEGS) I through IX plants in the Mohave Desert in southern 

California. The SEGS plants were built in the 1985 to 1991 time frame. Figure A-2 

shows the Kramer Junction site with five 30 MW SEGS plants. The largest of the SEGS 

plants, SEGS IX, located at Harper Lake, is 80 MW. All of the SEGS plants are 

“hybrids,” using fossil fuel to supplement the solar output during periods of low solar 

radiation. Each plant is allowed to generate 25 percent of its energy annually using fossil 

fuel. With the use of the fossil hybrid capability, the SEGS plants, during Southern 

California Edison (SCE) on-peak hours, have exceeded 100 percent capacity factor for 

more than a decade, with greater than 85 percent from solar operation. 

 In general, the SEGS plants are operating well. Operation and maintenance 

(O&M) costs have dropped sharply over time, coincident with performance gains. 

Although component reliability has generally been good, there have been issues. 

Modifications have been made to improve the lifetimes of mirrors and receivers. New 

models of HCEs from current suppliers appear to perform better than the original HCEs, 

with evidence of significantly reduced failure rates. The availability of spare parts was 

April 21, 2006 A-4 
NREL CA Solar Benefits Appendix A 

limited in the early 1990’s due to the commercial failure of the supplier. With the 

development of new suppliers, plant operation has been excellent. Development of 

improved components and subsystems has also contributed to performance gains over the 

last decade. 

Figure A-2 

Kramer Junction Trough Plant 

(Source: NREL) 

 A performance history from 1985 to 2003 for the Kramer Junction plants is shown 

on Figure A-3. The period from 1985 to 1990 has low generation because plants were 

being brought on-line during that period. Since 1991, energy production has been quite 

consistent, with the low generation in 1992 resulting from low DNI because of the 

worldwide effects of a volcanic eruption in the Philippines. 

April 21, 2006 A-5 
NREL CA Solar Benefits Appendix A 

A.1.2 Planned Trough Plants 

 There are several commercial projects in the planning or active project 

development stage. A 1 MW plant has been constructed in Arizona, with the plant 

currently in startup. Plants in the development stage include a 64 MW plant under 

construction in Nevada and a several 50 MW plant to be constructed in Spain. 

Indications are that the early Spanish plants will include 7 hours of thermal storage. 

Other projects in various stages of planning include integrated solar combined cycle 

system (ISCCS) in southern California, India, Egypt, Morocco, Mexico, and Algeria. In 

addition, there are plans for a series of SEGS type plants in Israel. 

0

200

400

600

800

1,000

1985 1987 1989 1991 1993 1995 1997 1999 2001 2003

Year of Operation

Annual Gross Solar Generation 

(GWh)

0

2

4

6

8

10

Cumulative Gross Solar 

Generation (TWh)

Cumulative Generation

Annual Generation

Figure A-3 

Kramer Junction Annual Performance33

A.1.3 Trough Infrastructure Status 

 Parabolic trough systems are considered commercially available for industrial 

applications. The primary developers of this technology include Solargenix Energy 

(USA), Solel Solar Systems (Israel), and Solar Millennium (Germany). Suppliers of 

components for trough systems include reflector supplier Flabeg (Germany) and receiver 

suppliers Schott Glass (Germany) and Solel Solar Systems. 

 The currently planned technology, for thermal storage, is the molten salt two-tank 

system. This provides a feasible storage capacity of up to 12 hours and is considered to 

have a low-to-moderate associated risk. 

 

33 Kearney, D., Price, H., “Advances in Parabolic Trough Solar Power Technology,” Advances in Solar 

Energy. Vol 16, Kreith, F., Goswami, D.Y. (Eds.), ASES, Boulder, Colorado, 2005.

April 21, 2006 A-6 
NREL CA Solar Benefits Appendix A 

 Water requirements depend on the design and configuration of the trough system. 

If wet cooling is used, water consumption is about 2.8 m3/MWh, similar to conventional 

steam plants; in addition, about 0.14 m3

/MWh of water is needed for washing the solar 

field. Dry cooling reduces water consumption drastically, but also reduces performance 

and increases cost. 

 Siting requirements for a parabolic trough system include level land, with less 

than 1 percent slope desirable. Solar fields are typically graded in two or more terraces 

for a full plant. The cost for grading is a small portion of the total cost (for relatively flat 

sites). 

A.2 Parabolic Dish-Engine Systems 

 A solar parabolic dish-engine system comprises a solar concentrator (or 

“parabolic dish”) and the power conversion unit (PCU). The concentrator consists of 

mirror facets which form a parabolic dish, which redirects DNI to a receiver mounted on 

a boom at the dish’s focal point. The system uses a two-axis tracker such that it points at 

the sun continuously. 

 A parabolic dish-engine system using an efficient Stirling engine is shown on 

Figure A-4. The PCU includes the thermal receiver and the engine-generator. In the 

solar receiver, radiant solar energy is converted to heat in a closed hydrogen loop. The 

heated hydrogen drives the Stirling engine-generator. Because the PCUs are air cooled, 

there is no cooling water requirement as is necessary for the large, central power blocks 

associated with trough and power tower technologies. Thermal storage is not currently 

considered to be a viable option for dish-Stirling systems. 

Figure A-4 

Dish-Stirling System 

(Source: NREL) 

April 21, 2006 A-7 
NREL CA Solar Benefits Appendix A 

 Relatively level land is preferable for construction and maintenance ease; 

however, siting requirements on slope are likely less significant than those for trough and 

tower systems. 

 Individual dish-Stirling units range in size from 10 to 25 kW. Because they can 

operate independent of power grids, they can be used for remote applications as well as 

grid connected applications. With their high efficiency and modular construction, the 

cost of dish-engine systems is expected to be competitive in distributed markets. Stirling 

Engine Systems (SES), the principal dish-Stirling developer in the United States, projects 

that the cost of dishes will decrease dramatically with hundreds of MWs of central 

station, grid connected deployment. 

 There are no operating commercial dish-Stirling power plants. Recently 

installation was completed on a six dish test deployment at Sandia National Laboratories 

(SNL) in Albuquerque. This development is under a joint agreement between SES of 

Phoenix and SNL. On August 2, 2005, Southern California Edison publicly announced 

the completion of negotiations on a 20 year power purchase agreement with SES for 

between 500 to 850 MW of capacity (producing 1,182 to 2010 GWh/year) of 

dish/Stirling units. On September 7, 2005, SES announced a contract with San Diego 

Gas & Electric to provide between 300 and 900 MW of solar power using the dish 

technology. Pricing for these power purchase agreements remain confidential. This large 

deployment of dish Stirling systems is expected to drastically reduce capital and O&M 

costs and to result in increased system reliability. 

 Other planned deployments of dish-engine systems included contracted deployments of a 25 kW demonstration dish by SES at Eskom in South Africa and a 10 kW 

Schlaich Bergermann und Partner (SBP) dish providing power to the grid in Spain. 

Proposed or planned deployments include a 10 kW SBP dish in France and a 10 kW SBP 

dish in Italy. 

A.3 Power Tower Systems 

 A power tower uses thousands of sun-tracking mirrors called heliostats to redirct 

DNI to a receiver at the top of a tower. In the most recent receiver deployment, a molten 

nitrate salt HTF heated in the receiver is used to generate steam, which, in turn, was used 

in a conventional turbine generator to produce electricity. An earlier power tower 

generated steam directly in the receiver; however, the current US design uses molten 

nitrate salt because of its superior heat transfer and energy storage capabilities. 

Commercial power tower plants can be sized to produce anywhere from 50 to 200 MW of 

electricity. Systems with air as the working fluid in the receiver or power system have 

also been explored in international research and development programs. A schematic 

diagram of the power tower technology is shown on Figure A-5. Figure A-6 is a 

photograph of the 10 MW Solar Two prototype molten salt system. 

April 21, 2006 A-8 
NREL CA Solar Benefits Appendix A 

Figure A-5 

Power Tower System Schematic 

Source: Adapted from SunLab (SNL and NREL) 

Figure A-6 

10 MW Solar Two Power Tower System 

(Source: NREL) 

April 21, 2006 A-9 
NREL CA Solar Benefits Appendix A 

 An advantage of power tower plants is that molten salt can be heated to 1,050 oF, 

with steam generation at 1,000 o

F, which is utility standard main steam temperature. This 

results in a somewhat higher cycle efficiency than is achievable with the lower 

temperature (about 735 oF) steam achievable with a trough system. Furthermore, power 

towers have the advantage that the molten salt is used both as the HTF and as the storage 

medium, unlike the trough system which uses a high temperature oil as the HTF, and 

requires oil-to-salt and salt-back-to-oil heat exchange for thermal storage. The result is 

that storage is less costly and more efficient for power tower than for troughs. 

 There are no commercial power tower plants in operation. The 10 MW Solar One 

plant near Barstow, California, operated from 1982 to 1988, producing over 38 million 

kilowatt-hours (kWh) of electricity. Solar One generated steam directly in the receiver. 

To implement improved heat transfer and thermal storage, the plat was retrofitted (and 

renamed Solar Two). Solar Two operated from 1998 to 1999. Although Solar Two 

successfully demonstrated efficient collection of solar energy and dispatch of electricity, 

including the ability to routinely produce electricity during cloudy weather and at night, 

the plant encountered various technical issues. Solutions to these issues have been 

identified; however, successful demonstration of certain improvements is required prior 

to commercial financing of a large-scale plant. 

 In addition to Solar One and Solar Two, experimental and prototype systems have 

operated in Spain, France, and Israel. Solucar Energia, S.A., an Abengoa company, 

recently announced a 11-megawatt solar power tower near Seville. Called PS 10, the 

power plant will be the largest solar power system in Europe and the first tower-based 

solar power system to generate electricity commercially. In addition, ESKOM, the large 

utility in South Africa, is considering a 100 MW molten-salt plant. A 17 MW molten salt 

plant in Spain, Solar Tres, was in planning by Ghersa, Boeing, and Nexant. However, 

this plant appears to be unlikely at this time. 

 Potential component suppliers include heliostat supplier Sener and Inabensa in 

Spain. The Rocketdyne Unit of Boeing provided the molten salt receiver for Solar Two, 

and has been positioned to provide all molten salt equipment (receiver, thermal storage, 

steam generator) for a new power tower plant. Boeing recently announced the sale of the 

Rocketdyne Unit to Pratt & Whitney. The long term impact of this sale on solar 

equipment supply is not known. 

 Cooling water requirements are about 2.8 m3

/h per MWh, which include a small 

amount for heliostat washing. Dry cooling reduces this water consumption drastically, 

although, as with the trough system, performance is reduced and cost increased. 

 As with the trough system, level land is preferable, with less than 1 percent slope 

desirable. The land area must be one continuous parcel with essentially a circular 

footprint. 

April 21, 2006 A-10 
NREL CA Solar Benefits Appendix A 

A.4 CPV Systems 

 Concentrating photovoltaic (CPV) systems have potential for cost reduction 

compared with conventional, non-concentrating (also referred to as flat plate) PV systems 

in two key ways. First, a major portion of conventional PV system cost is for the 

semiconductor material which makes up the PV modules. By concentrating sunlight onto 

a small cell, the amount of semiconductor can be reduced, albeit at additional cost for 

mirrors or lenses and for tracking equipment. Second, use of smaller cells allows for 

more advanced and efficient cell technology, making the overall system efficiency higher 

than for a conventional flat plate system. 

 CPV systems have been under development since the 1970’s. This development 

has included single axis tracking, line focus CPV and two axis tracking, point focus CPV. 

Recent development has primarily been on the two-axis tracking systems. There are two 

primary developers of CVP systems today: Amonix, a company based in Torrance, 

California, and Solar Systems Pty, Ltd, located in Australia. 

 The Amonix CPV unit, shown on Figure A-7, produces 25 to 35 kW per tracker, 

depending on how many modules are installed on the tracker. The Amonix system uses 

hundreds of acrylic Fresnel lenses to focus DNI on high concentration PV cells. Heat 

rejection is passive, meaning there is no water requirement and no closed loop radiator 

system The Amonix unit currently has an average annual efficiency of 15.5 percent. 

Figure A-7 

Amonix: Flat Acrylic Lens Concentrator with Silicon Cells 

(Source: NREL) 

April 21, 2006 A-11 
NREL CA Solar Benefits Appendix A 

 Amonix systems have been deployed at Arizona Public Service (APS) facilities 

for a total capacity of 547 kW. Planned deployments in the near future include 10 to 

20 MW in Spain. Currently, the systems use high-efficiency silicon cells. Efficiency and 

capacity gains are expected with advance triple-junction cells and higher concentration. 

 Solar Systems Pty, Ltd, has a different approach to CPV, using a parabolic dish 

concentrator to focus DNI on a high concentration PV receiver. This 24 kW system, 

shown on Figure A-8, averages about 15 to 16 percent efficiency. Ten dishes have been 

deployed since 2003, for a total capacity of 220 kW, with the construction of an 

additional 720 kW under way. Several MW of contracts are anticipated in the relatively 

near future. The next generation of higher efficiency CPV modules is expected to 

increase the capacity to 35 kW in 2005. The core CPV technology, which accounts for 

about 25 percent of the cost, would be manufactured in Australia, with the remainder to 

be manufactured in the United States for a California deployment. 

 A 50 MW CPV plant would consist of 2,000 25 kW units or 1,430 35 kW units. 

Similar to the dish-Stirling systems, no cooling water is required for operation. CPV 

systems have an annual capacity factor of about 26 percent. Near-term R&D is focused 

on reliability validation, module cost reduction (packaging), and advanced cell 

technology, e.g., III-V multijunction technology. Similar to the dish systems, level land is 

preferable for construction and maintenance ease, although it is likely a less significant 

requirement for CPV sites than that required by trough and tower systems. 

Figure A-8 

Solar Systems Pty, Ltd: Parabolic Dish PV Concentrator 

(Source: NREL) 

April 21, 2006 A-12 
F1146-E(12/2004) 

REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

collection of information, including suggestions for reducing the burden, to Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents 

should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a 

currently valid OMB control number. 

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE (DD-MM-YYYY)

April 2006 

2. REPORT TYPE

Subcontract Report 

3. DATES COVERED (From - To)

May 2005 - April 2006 

5a. CONTRACT NUMBER

DE-AC36-99-GO10337 

5b. GRANT NUMBER

4. TITLE AND SUBTITLE

Economic, Energy, and Environmental Benefits of Concentrating 

Solar Power in California 

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

NREL/SR-550-39291 

5e. TASK NUMBER

CP06.5002 

6. AUTHOR(S)

L. Stoddard, J. Abiecunas, R. O'Connell 

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

Black & Veatch 

11401 Lamar Ave. 

Overland Park, KS 66211 

8. PERFORMING ORGANIZATION 

REPORT NUMBER

AEK-5-55036-01 

10. SPONSOR/MONITOR'S ACRONYM(S)

NREL 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Renewable Energy Laboratory 

1617 Cole Blvd. 

Golden, CO 80401-3393 11. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

NREL/SR-550-39291 

12. DISTRIBUTION AVAILABILITY STATEMENT

National Technical Information Service 

U.S. Department of Commerce 

5285 Port Royal Road 

Springfield, VA 22161 

13. SUPPLEMENTARY NOTES

NREL Technical Monitor: Mark Mehos 

14. ABSTRACT (Maximum 200 Words)

This study provides a summary assessment of concentrating solar power and its potential economic return, energy 

supply impact, and environmental benefits for the State of California. 

15. SUBJECT TERMS

Solar power tower; concentrating photovoltaics; concentrating PV; Dish engine systems; Dish Stirling; concentrating 

solar power; solar parabolic trough; solar trough; parabolic trough 

16. SECURITY CLASSIFICATION OF: 19a. NAME OF RESPONSIBLE PERSON 

a. REPORT 

Unclassified 

b. ABSTRACT 

Unclassified

c. THIS PAGE 

Unclassified

17. LIMITATION 

OF ABSTRACT

UL 

18. NUMBER 

OF PAGES 

19b. TELEPHONE NUMBER (Include area code)

Standard Form 298 (Rev. 8/98) 

Prescribed by ANSI Std. Z39.18