SERI/TP-260-3772 

UC Category: 233 

DE90000337 

C02 Emissions from 

Coal-Fired and Solar 

Electric Power Plants 

F. Kreith 

P.Norton 

D. Brown 

May 1990 

Prepared under Task No. 2000.4010 

Solar Energy Research Institute 

A Division of Midwest Research Institute 

1617 Cole Boulevard 

Golden, Colorado 80401-3393 

Prepared for the 

U.S. Department of Energy 

Contract No. DE-AC02-83CH 10093 
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 

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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. 

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at the above address. 
PREFACE 

This report presents estimates of the lifetime carbon dioxid~ 

emissions from coal-fired, photovoltaic, and solar thermal electric 

power plants in the United States. These CO2 estimates are based on a 

net energy analysis derived from both operational systems and detailed 

design studies. The implications of the results for planning a 

national energy policy are also discussed. 

The authors would like to thank Thomas D. Bath of the Solar Energy 

Research Institute (SERI) and Prof. R. E. West of the University of 

Colorado for their constructive criticism of the manuscript. 

iii 
TABLE OF CONTENTS 

1.0 Introduction 

2.0 Options for Reducing CO2 Generation 

2.1 

2.2 

2.3 

2.4 

2.5 

A Method of Estimating CO2 Emissions 

Solar Thermal Power Plants . . . . . 

Photovoltaic Power Plants .. . . . 

A Comparison of Solar and Coal-Fired Electric 

Power Plants . . . . . . . . . . . . 

The Potential of Cogeneration for Reducing 

CO2 Production 

3.0 Discussion 

4.0 Implications for a National Energy Policy 

5.0 References 

Appendix: Component costs for Molten-Salt Central Receiver 

and Photovoltaic Systems . . . . . . . . . . . . 

iv 

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1 

3 

4 

5 

11 

13 

21 

24 

28 

29 

32 
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LIST OF FIGURES 

Figure 

1-1 Global temperature change, CO2 concentration, and 

annual carbon production for the past 140 years 2 

2-1 Schematic diagram of a molten-salt central receiver 

power plant . . . . . . . . " .... 6 

2-2 ARCO Solar Industries' 1600-ft2 glass mirror heliostat 7 

2-3 Energy consumption per dollar of gross national 

product . . . . . . . . . . 11 

2-4 The City of Austin's PV300 (300-kWe ) photovoltaic 

power plant . . . . . . . . . . . 13 

2-5 EPRI's plant arrangement for the one-axis tracking flatplate photovoltaic power plant . . . . . . 15 

2-6 EPRI's one-axis, tracking, flat-plate system structural 

support concept . . . . 16 

2-7 Total CO2 production per GWhe of output energy 20 

2-8 Schematic diagrams of combined heat and electricity 

cogeneration systems ............... 21 

v 
LIST OF TABLES 

Table 

2-1 U. S. Fossil Fuel Use Distribution and CO2 Production 

per Unit of Primary Fossil Energy Used in the 

United States . . . . . . . . . 

2-2 Prime Contractors Supplying Cost Data for the 100-MWe 

Solar Thermal Power Plant . . . . . . . . . . . 

2-3 Solar Thermal Power Plant System Design and Performance 

Specifications 

2-4 Cost, Embodied Energy, and CO2 Production of the Key 

Components of the 100-MWe Solar Thermal Power Plant 

2-5 Energy Investment in the Energy Conversion Subsystem 

of the Solar Thermal Power Plant .... 

2-6 Cost, Embodied Energy, and CO2 Production of the Key 

Components of the City of Austin's 300-kWe 

Photovoltaic Plant . . . . . 

2-7 Key Design Characteristics for the EPRI Flat-Plate, 

One-Axis, Tracking Photovoltaic Central Station 

Design ....... . ..... . 

2-8 Cost, Embodied Energy, and CO2 Production of the Key 

Components of the EPRI Single-Axis, Tracking 

Photovoltaic System at the Southwest Site 

2-9 Cost, Embodied Energy, and CO2 Production of the Key 

Components of the EPRI Single-Axis, Tracking 

Photovoltaic System at the Southeast Site 

2-10 Net Lifetime Energy Output and CO2 Production per GWhe 

for Electric Power Plants with a 30-year Lifetime 

2-11 Potential for Reducing CO2 by Using Cogeneration 

Systems 

3-1 Comparison of CO2 Production per GWhe Net Lifetime 

Energy Output for Various Electric Power Technologies 

A-1 Receiver Component Costs and Material Weights for the 

Solar Thermal System . . . . 

A-2 Tower Component Costs for the Solar Thermal System 

A-3 Heliostat Material Costs for the Solar Thermal System 

vi 

TP-3772 

5 

5 

8 

9 

10 

14 

15 

17 

18 

19 

23 

26 

33 

33 

34 
LIST OF TABLES (CONCLUDED) 

Table 

A-4 Transport System Material Costs for the Solar Thermal 

System ...... . 

A-5 Storage System Component Costs for the Solar Thermal 

System 

A-6 Energy Conversion System Component Costs for the 

Solar Thermal System 

A-7 Balance-of-Plant Costs for the Solar Thermal System 

A-8 Operation and Maintenance Costs for the Solar Thermal 

System ...... . 

A-9 Cost and Embodied Energy of the City of Austin's 

300-kW Photovoltaic Plant ......... . 

A-10 Cost and Embodied Energy of the EPRI Single-Axis 

Tracking Photovoltaic System at the Southwest Site 

A-11 Cost and Embodied Energy of the EPRI Single-Axis 

Tracking Photovoltaic System at the Southeast Site 

vii 

TP-3772 

35 

35 

36 

37 

37 

38 

39-41 

42-44 
S=~I Ilfl TP-3772 

1.0 INTRODUCTION 

Human activities can affect the heat balance of the Earth, the 

atmosphere, and space. In particular, burning fossil fuels increases 

the carbon dioxide (C02 ) concentration in the atmosphere and thus induces 

global warming by virtue of a mechanism commonly referred to as the 

"greenhouse effect" (Ramanathan 1988). This is the mechanism by which 

the atmosphere controls the Earth's temperature. It depends on the high 

transmissivity of atmospheric gases to radiation in the short-wavelength 

range, in which the major part of incoming sunlight reaches the Earth, 

and the opaqueness of these same gases to the infrared (IR) radiation 

emanating from the Earth. The absorption of solar radiation warms the 

Earth's surface, whereas the IR radiation emitted by the surface tends 

to cool the Earth. But the atmosphere absorbs more and more of this IR 

energy as the concentration of CO2 builds up, and more heat is trapped in 

the lower atmosphere. The temperature of the Earth then increases to 

maintain a heat balance between incoming and outgoing radiation. 

Figure 1-1 shows the average global temperature deviation from the mean, 

the CO2 concentration in the atmosphere, and annual carbon production as 

a function of time over the last 140 years. There are still questions 

about its exact magnitude, but all the available evidence points to a 

rise in the average global temperature as the CO2 concentration increases. 

These data indicate that the burning of fossil fuels, coupled with the 

destruction of vast forests, have led to a rise in CO2 concentration 

approximately 25% above the level that existed before humans began 

interfering with the Earth's natural heat balance. 

According to Bath and Feucht (1990), current estimates of global CO2 

emissions from fossil fuel use (expressed as gigatons of carbon) are 

about 5.1 GT per year. Reductions of biologically fixed carbon, mostly 

from deforestation, add about 1 to 1.5 GT of carbon to the atmospheric 

input. Of this annual total of about 6.5 GT of carbon, roughly 3 to 

3.5 GT are removed from the atmosphere by the oceans, leaving a net input 

of about 3 GT of carbon per year. This agrees with the observed rate of 

increase in atmospheric CO2 (0.5% per year) and suggests with some 

confidence that a 50% reduction from current emission levels would bring 

the atmospheric carbon cycle back into balance, stabilizing the CO2 

concentration in the atmosphere (Bath and Feucht 1990). However, if we 

continue burning fossil fuels at current rates, the buildup of CO2 in the 

atmosphere will trap increasing amounts of infrared radiation emitted by 

the Earth and result in a warming of the Earth's surface. 

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TP-3772 

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1850 1870 1890 1910 1930 1950 1970 1990 

350 

340 (b) 

330 

320 

310 

300 

290 

280 

1850 1870 1890 1910 1930 1950 1970 1990 

6x109 

5x109 (c) 

4x109 

109 

2x109 

/1" ........ 

1x109 -- .... --" --- 0 

1850 1870 1890 1910 1930 1950 1970 1990 

G1oba1 temperature change, CO2 concentration, and annua1 

carbon production for the past 140 years. Graph (a) shows 

the annual mean (spiky curve) and the 5-year mean (smooth 

curve} global temperature. Graph (b) shows the atmospheric 

CO2 content. (Pre-1958 data come from analysis of air 

trapped in bubbles of glacial ice from around the world.) 

The annual production of carbon from fossil-fuel burning 

(solid line) and from changes in land use (dashed line) 

is shown in graph (c). (Source: Houghton and Woodwell 

1989. Reproduced with permission.) 

2 
S=~II_I TP-3772 

2 . 0 OPTIONS FOR REDUCING CO2 GENERATION 

Five basic options for reducing CO2 generation have been proposed 

(Morrison 1989; Jaeger 1988). These are as follows: 

1. Increase the end-use efficiency of fuel use by conservation and 

improved energy conversion. Technologies exist for energy conservation and improved utilization by measures such as better insulation, 

cogeneration, or increased gas mileage; a reduction in overall energy 

consumption of up to 50% is achievable with available means. 

2. Replace fossil fuels with renewable energy sources. As this report 

shows, this is the only viable long-term strategy to provide power 

without curtailing growth. Appropriate technology is available, but 

the optimum system (e.g., wind, solar or nuclear energy for electric 

power, solar thermal energy for domestic hot water, etc.) depends on 

geographic location and end use. Implementing this option would 

require a national energy plan with appropriate regulations and 

economic incentives. 

3. Reverse the trend of deforestation. As much as 20% of worldwide CO2 

emissions due to human activities comes from burning forests. Eliminating burning and instituting accelerated reforestation would reduce 

emissions and absorb atmospheric CO2 as the trees grow and store carbon in their biomass. At present, however, it is estimated that 

only one tree is planted for every 11 or 12 trees cut down. In 

Brazil's Amazon Basin alone, 20,000 to 40,000 km2 of forest land is 

cleared annually. 

4. Shift from coal to natural gas. The combustion of natural gas produces about 40% to 50% less carbon dioxide per unit energy delivered 

than the combustion of coal {Marland and Rotty 1983). However, estimates of the amount of natural gas available in the United States 

have recently plummeted (Kerr 1989), and appreciable amounts of CO2 

would still be produced by natural gas systems. Hence, switching fuel 

is at best a temporary amelioration and not a long-term solution. 

5. Collect and dispose of CO2 • Liquid solvents, solid adsorbents, and 

separation processes could be used to remove carbon dioxide from flue 

gases. Although CO2 emissions from coal-fired power plants could be 

reduced by up to 90%, the power generation of those plants would thus 

be reduced by as much as 70%. In addition to the extreme cost, transportation and final disposal of the CO2 present unresolved problems. 

Concern about deleterious climate changes resulting from global warming 

has led to recommendations designed to reduce emis.sions of CO2 • The 

recommendations outlined above include energy conservation, reforestation, cogeneration, and substituting natural gas, nuclear, and solar 

energy for coal and oil. However, U. S. energy policy since 1973 has 

largely'emphasized the substitution of coal for oil to protect national 

security interests. Hence, the goal of reducing CO2 production could 

conflict with u.s. energy security measures. To avoid such a conflict, 

it is necessary to adopt a long-range energy policy that takes the various interests into account and reduces CO2 production without curtailing 

3 
TP-3772 

economic activities a To develop such a policy it is necessary to know 

the amount of CO2 that would be emitted from different energy conversion 

and conservation technologies. In this report we estimate the CO2 production of solar thermal, photovoltaic, and coal-fired electric power 

plants operating· in the "electricity only" mode and as cogeneration systems. This information may be useful to energy planners in developing 

realistic options for long-term energy policy. 

2 . 1 A Method of Zst:l.matinq CO2 Emissions 

A method for calculating the energy return on (energy) investment (EROI) 

for renewable energy conversion systems has been demonstrated by Kreith 

et al. (1987). Subsequently, Kreith and Norton (1989) showed how to 

apply the EROI to calculate CO2 generation for renewable and nonrenewable 

energy sources. 

In this approach, the total amount of CO2 generated during the life of a 

power plant is calculated by adding the CO2 generated during construction 

and decommissioning to the CO2 generated from burning fossil fuels and 

from operation and maintenance (O&M) of the plant. The CO2 generated 

during the construction of a power plant is calculated by multiplying the 

primary energy investment in each component of the plant by the average 

CO2 production per unit of primary energy used by the U. S. energy 

infrastructure. 

The CO2 production per unit of primary fossil energy for coal, oil, and 

natural gas is calculated from the carbon content and the stoichiometric 

equations of combustion for each of the fossil fuels. Carbon dioxide 

production from coal, oil, and natural gas has been calculated by several 

sources, including the U.S. Department of Energy (DOE) and the Congressional Research Service (CRS) (Marland and Rotty 1983; Morrison 1989; 

Lovins et ale 1981; Kreith and Norton 1989). The results of these calculations agree within 10%. One reason for this discrepancy is the difference in assumptions about the carbon content in fossil fuels and the 

coal chemistry. The DOE data base of Marland and Rotty (1983) is the 

most extensive of these studies and will be used in our analysis. The 

U.S. fossil energy use distribution (Mac~enzie 1988) is shown in the 

first column of Table 2-1 in Gwb of energy from a given fossil fuel 

source per GWh of energy delivered from all fossil fuel sources. Multiplying the energy from a given fossil fuel per GWh from all fossil fuels 

by the metric tons of CO2 per GWh for that fuel yields the tons of CO2 

produced per GWh of primary fossil fuel use. Summing the third column 

of Table 2-1 shows that an average of about 255 metric tons of carbon 

dioxide is produced for every GWh of primary fossil fuel energy used in 

the United States. 

Kreith and Norton (1989) compared the CO2 generation for residential 

photovoltaic and large wind energy conversion systems with the CO2 

generation from coal- and oil-fired electric power plants by the method 

described above. The data bases for these CO2 generation estimates were 

the economic profiles of selected solar technologies prepared jointly in 

1982 by Los Alamos National Laboratory (LANL) and the Solar Energy 

Research Institute (SERI) (Mann and Neenan 1982) . Since the LANL-SERI 

4 
TP-3772 

Table 2-1. u.s. Fossil Fuel Use Distr1bution and CO2 Production per 

Unit of Pr~ry Fossil Energy Used in the United States 

Fractional Energy CO2 Produced per CO2 Produced 

from Fuel Sources GWh from Each Fuel per GWh of 

per GWh of Primary Source of Primary Primary Fossil 

Fossil Energy Used Fossil Energy Fuel Energy 

(U. S. ) (Mackenzie (Marland and Rotty Used (U. S. ) 

1988) 1983) (metric tons) (metric tons) 

Coal 0.26 GWh 315 81. 9 

Oil 0.49 GWh 260 127.4 

Natural gas 0.25 GWh 182 45.5 

Total 1. 00 GWh 254.8 

Table 2-1 study did not include solar thermal power plants or large-scale 

photovoltaic plants, data bases for these electric generation technologies had to be developed in order to calculate their CO2 generation. 

2.2 Solar Thermal Power Plants 

The data base for solar thermal power plants was generated by Battelle 

Pacific Northwest Laboratory (PNL), using cost data supplied by the prime 

contractors listed in Table 2-2 for a design for a 100-megawatt (electric) (MWe ) solar thermal central-receiver electric power plant. The 

procedure is described in detail by Brown (1988); key results are given 

below. 

Table 2-2. Prime Contractors Supplyinq Cost Data for the 

100-MII. Solar Thermal. Power Pl.ant (Brown 1988) 

Arizona Public Service [1-3]a 

Bechtel [4-6] 

Black and Veatch [7, 8] 

El Paso Electric Company [9, 10] 

Exxon [11] 

General Electric [12] 

Honeywell [13] 

Jet Propulsion Laboratory [14] 

Martin Marietta [15] 

McDonnell Douglas [16, 17] 

Northrup (ARCO) [18] 

Rockwell International [19-21] 

Sandia National Laboratories [22, 23] 

Southern California Edison [24] 

Stearns-Roger [25, 26] 

U.S. Department of Energy [27] 

aNumbers in brackets refer to references in D. R. Brown., "Cost 

Drivers for Solar Thermal Central Receiver Power Plants" (Brown 

1988) . 

5 
TP-3772 

The central-receiver system analyzed is shown schematically in Figure 2-1. It uses an established technology based on a molten nitrate 

salt working fluid. Heliostats track the sun in two axes, redirecting 

the incident solar energy onto a tower-mounted receiver. The energy 

absorbed at the receiver heats the molten salt to 1050°F (840 K); the 

molten salt is then transported through pipes to the storage subsystem 

and subsequently to a four-shell recirculating steam generator that 

powers a water/steam Rankine-cycle heat engine. 

r------------------------------------------------------------------------,N 

Beam 

characterization 

system 

Support Systems 

• Back-up power 

• Switchyard 

• Roads 

• Warehouse • Fire protection 

• Administration building 

• Water supply 

o 

<Xl 

a 

:g 

(9 

.{ 

co 

Figure 2-1. Schematic diagram of a molten-salt central receiver power 

plant (Source: US DOE 1985) 

The heliostat field, which is the most energy-intensive component of the 

system, uses a 1600-ft2 (148.6-m2 ) glass mirror design developed by AReO 

Solar Industries that was scaled up from a 1024-fe (95 .1-m2 ) design 

described by Rockwell International (1983). Stretched-membrane heliostats use a more advanced design, which affords a radically lower cost, 

6 
TP-3772 

less energy investment, and less CO2 production (Murphy 1986). But additional development is necessary to achieve the design maturity and reliability of the glass mirror design used in this analysis (Alpert and 

Houser 1989). A drawing of ARCO's 1600-ft2 (148.6 m2 ) heliostat is shown 

in Figure 2-2. 

Figure 2-2. ARCO Solar Industries' 1600-ft2 (148.6 m2

) glass mirror heliostat 

The receiver design is described by Weber (1983). It uses a C-shaped 

cavity receiver with a vertical orientation for the absorber panels. 

The transport subsystem connects the receiver, storage, and steam generator subsystems. Principal components include the riser and downcomer 

within the receiver tower, ground-level piping, pumps, valves, and fittings. The storage subsystem consists of a "hot" tank for storing molten 

7 
TP-3772 

salt at 1050°F (839 K), a "cold" tank for storing molten salt at 550°F 

(561 K), and a salt treatment and makeup system. The steam generator is 

composed of preheating, evaporating, superheating, and reheating heat 

exchangers. 

The design specifications and the predicted annual performance for the 

molten-salt central-receiver (MSCR) solar thermal power plant are sum-

.marized in Table 2-3. For the CO2 generation calculation, the availability was taken as 90%, a level that is considered reasonable for a 

future mature system. Table 2-4 shows a breakdown of the costs of the 

receiver, the tower, the transport piping, the storage facility, the 

heliostat field (including support structures and controls), the energy 

conversion system, and the balance of the plant. Also included is the 

cost of labor for the assembly and installation of each component of the 

MSCR solar thermal system. The final item is the estimated yearly O&M 

cost for the system. All of the cost data in the second column of 

Table 2-4 are in 1977 dollars. They were obtained by applying the appropriate inflation factor to the cost estimates in 1984 dollars provided 

by Brown (1988), using data published by the U.S. Department of Commerce 

(West 1988). A detailed breakdown of the system costs and materials is 

contained in the appendix. 

Tab~e 2-3. So~ar Therma1 Power P~ant System Design and Performance Specifications (Williams et ale 1987) 

Construction time (years) 

Net generating capacity (MWe ) 

Heliostat field size (1000 m2 ) 

Storage capacity (MWht ) 

Storage time (h) 

Plant capacity factor 

Annual (solar) energy input (kWht /m2 ) 

System annual efficiency (solar to electric) 

Annual energy output (kWhe ) 

aAssumes 100% availability. 

3 

100 

733 

1139 

4.4 

O.4a 

2848 

18.6%a 

3.883 E8a 

The procedure for calculating the embodied energy of the subsystems in 

the third column of Table 2-4 is given in detail by Kreith et ale (1987) 

and is illustrated for the energy conversion subsystem in Table 2-5. The 

first column lists the item, the second column the cost in 1984 dollars 

($1984), the third column the same cost in $1977, the fourth column the 

appropriate standard industrial code (SIC) of the item, the fifth column 

the SIC sector, and the sixth column the embodied energy per dollar for 

this SIC code, obtained from Hannon et ale (1985). The seventh column 

shows the embodied energy in that item based on the energy efficiency of 

the United States in 1977. However, U.S. energy consumption per dollar 

of gross national product (GNP) has decreased since 1977, as shown in 

Figure 2-3. 

8 
1.0 

Table 2-4. Cost, Embodi.ed Energy, and CO2 Production of the Key Components of 100 MR. 

Solar Thermal Power Plant 

Cost Cost Embodied Energy CO2 Production Percent of 

Component (107 $1984) (107 $1977) (GWh of primary energy) (metric tons of CO2 ) Total CO2 

A.l Receivera 1.7 1.1 121 30,831 6.6 

A.2 Tower 0.6 0.4 75 19,110 4.4 

A.3 Heliostats 7.3 4.6 581 148,039 33.3 

A.4 Transport 1.0 0.5 60 15,288 3.3 

A.5 Storage 1.6 1.0 170 43,316 9.3 

A.6 Energy conversion 3.8 2.4 172 43,826 9.9 

A.7 Balance of plantb 2.6 1.6 103 26,244 6.0 

A.8 30 years of operation 11.4 7.0 478 121,794 27.4 

and maintenance 

Total for 30-Year Life 30.0 18.6 1760 448,448 100 

a Notations A.l, A.2, etc. , refer to the corresponding tables in the appendix that give the cost breakdown for 

each component. 

bBalance of plant includes land and land-related costs, buildings, fences, master control, service 

facilities, power conditioning, and spare parts. 

In 

III 

N 

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to 

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III 

N 

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If

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I I 

~-~ 

Table 2-5. Energy Investment in the Energy Conversion Subsystem of the Solar The~ Power Plant 

Parts $1984 $1977 SIC Code 

Turbine generator 15,500,000 9,650,000 530400 

Cooling tower, condenser, 

and ancillary Rankine 

equipment 15,500,000 9,650,000 490700 

Carbon steel preheater 1,150,000 716,000 400300 

Low-alloy steel evaporator 2,350,000 1,460,000 400300 

Stainless steel superheater 2,030,000 1,264,000 400300 

Stainless steel preheater 1,790,000 1,114,000 400300 

Energy 

Intensity 

SIC Sector (Btu/$1977 GNP) 

Motors, Generator 33556 

General Ind. Mach. 28793 

Heating Equipment 33553 

Heating Equipment 33553 

Heating Equipment 33553 

Heating Equipment 33553 

1977 1989 

Energy Energy 

Investment Investmenta 

(10 10 Btu) (10 10 Btu) 

32.38 25.1 

27.79 21.5 

2.40 1.9 

4.91 3.8 

4.24 3.3 

3.74 2.9 

Total: 

5.85 x lOll Btu 

primary energy -

172 GWh primary 

energy 

aThe figures in the preceding column for the energy investment in 1977 were corrected to reflect the 22.5% reduction 

in energy used per dollar of GNP between 1987 and the beginning of 1989. 
TP-3772 

.... 40 ~ 

'0 

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C\I 

co 30 en 

Total energy 

,-

.... 

Q) 

a. 

:::J 20 

lPetroleum and natural gas;---------_ 

- - - - __ '-__ .... """'----__ ----4 

ll) '-~ "0 

C 

--...... -_ ...... ---........, ......... _-------

rn 10 CJ) All other energy :J 

0 - -----..... -...... --- _ .. -.... -_ .... ---. -- .. -_ ........... --_ .... -. - ................ --- ...... - - ....... - .c 

I- O--~ __ ~ __ ~ __ ~ __ L_~~~ __ ~ __ ~ __ ~~~~ __ _L __ ~ __ ~~ 

19731974197519761977 1978 1979 19801981 19821983 198419851986 1987 1988 

Figure 2-3. Energy consumption per do~~ar of gross nationa~ product 

(Source: Energy Information Administration 1988) 

The United States now produces one dollar of GNP with 22.5% less energy 

than it did in 1977 (Energy Information Administration 1988). Therefore, 

the embodied energy based on the 1977 data must be reduced by 22.5% to 

obtain the embodied energy for a system built in 1989. This adjusted 

embodied energy is listed in the last column of Table 2-5. The CO2 

production for each component of the system is then calculated by multiplying the average CO2 per unit of primary energy for the U.S. energy 

infrastructure by the embodied energy of that component. 

Note that the energy efficiency correction is approximate because the 

energy utilization pattern has changed as a result of a realignment of 

U.S.-produced goods and those imported from other countries. For example, a considerable portion of the decline in U.S. energy intensity was 

the result of rising imports of energy-intensive goods such as automobiles and machinery, of higher new-car fuel efficiencies, and of reduced 

levels of energy used. in heating and cooling buildings. Also, this method 

does not include "non-energy" CO2 , which may be important in processes 

such as cement production, where CO2 from calcining C03 rock also produces 

CO2 • 

2.3 Photovo~taic Power P~ants 

Two data bases were used to study photovoltaic power plants; one is a 

small system in operation at Austin, Tex., and the other is a conceptual 

design. A comparison of these two systems provides both an indication 

of economies of scale and the improvement that occurs between a current, 

11 
TP-3772 

state-of-the-art system and a next-generation system that can draw on 

operational experience in its design. The cost and performance data for 

the City of Austin's 300-kWe plant were obtained from Panico (1989) and 

Hoffner (1989), respectively. Although this is a relatively small system 

by electric utility standards, it is of interest because actual cost and 

performance data are available. The data for a conceptual design for a 

large, 100-MWe photovoltaic power plant were obtained from a study conducted by the Electric Power Research Institute (EPRI) (Levy and Stoddard 

1984) . 

The City of Austin Electric Utility Department has been operating its 

nominal 300-kWe photovoltaic plant since December 1986. A full year of 

data for 1988 has been recorded and analyzed by Hoffner (1989). The 

plant has been highly reliable, with an availability greater than 99% 

and a 22% yearly capacity factor based on the actual-to-rated plant output. During 1988, the plant had an alternating-current (AC) net efficiency of 8.5% with a total net output of 484,957 kWhe-AC. The maintenance costs for the plant were $0.004/kWhe ($1988). The plant consists 

of a 3.5-acre field of 2620 m2 (gross) of single-crystal silicon cells. 

The cells are mounted on 42 single-axis passive trackers that rotate 

around a north-south, horizontal axis. The system uses a 300-kW Toshiba 

inverter with a design peak efficiency of 96% and is connected to the 

city's electric distribution system of 12,500 V AC. The total installed 

cost of the plant was $3 million in 1986. Figure 2-4 shows a photograph 

of the system. 

The costs, the embodied energy, and the CO2 production for the 300-kWe 

photovoltaic system components are presented in Table 2-6. A more 

detailed breakdown of the component materials, material costs, SIC sectors, energy intensity, and embodied energy is contained in the appendix. 

EPRI performed a design study of the performance and cost of 100-MWe 

photovoltaic central stations using fixed flat-plate, one-axis tracking 

flat-plate, two-axis tracking flat-plate, and two-axis tracking highconcentration collectors in the southwestern and southeastern United 

States (Levy and Stoddard 1984). The study concluded that the three 

flat-plate systems are potentially viable in the Southwest, but only the 

fixed and one-axis tracking systems are potentially economical in the 

Southeast. For this report, only the flat-plate one-axis tracking design 

was analyzed for CO2 production at both locations. The key design characteristics of this system are listed in Table 2-7. The plant layout and 

panel structural concept are shown in Figures 2-5 and 2-6, respectively. 

The construction of the plant is slightly different for the two locations, owing to variations in soil conditions and wind loading. Higher 

labor rates in the Southwest also cause a difference in systems costs. 

The Southwest site is at Barstow, Calif. The total net annual energy 

generation for the plant at this site is 228 GWhe. The total cost estimate of the plant at Barstow is $97 million ($1982). The Southeast site 

is at Bay Minette, Ala. The plant at Bay Minette has an estimated net 

annual output of 178 GWhe and a cost of $86 million ($1982). The annual 

operation and maintenance costs for this system were estimated to be 

$2.30/m2 ($1982) of photovoltaic panel. The costs, embodied energy, and 

12 
Figure 2-4. The City of Austin's PV300 (300-kW,,) photovol.taic power pl.ant 

CO2 production of the key components of the plants are shown in Tables 2-8 

and 2-9. Materials, material costs, SIC sectors, energy intensity, and 

embodied energy are shown in detail in the appendix. 

2.4 A Comparison of Sol.ar and Coal.-Fired El.ectric Power Pl.ants 

The lifetime CO2 production from construction, operation, and maintenance 

and the net electric power output for the three solar power plants are 

shown in Table 2-10, for a 30-year lifetime. Also shown in the table 

are the power output and CO2 production for a 747-MWe fluidized-bed, coalburning power plant. The performance of this type of coal plant was 

analyzed by Perry et. al (1977) and the CO2 production was calculated with 

the DOE data (Marland and Rotty 1983). These results are shown graphically in Figure 2-7. 

13 
~ 

"'" 

Tabl.e 2-6. Cost, Embod.i.ed Energy, and CO2 Production of the Key Components of the City of Austin's 

300-kW. Photovol.taic Pl.ant 

Actual Cost Cost Embodied Energy CO2 Production Percent of 

PV300 Plant Components (10 4 $1986) (104 $1977) (GWh of primary energy) (metric tons of CO2 ) Total CO2 

Photovoltaic panels 167.5 98.6 7.0 1784 42.5 

Power conditioning unit 23.4 13.7 1.2 306 7.1 

Structural subsystem 27 15.9 4.6 1172 27.8 

Electrical subsystem 10.8 6.4 0.6 153 3.8 

Nonessentials 10.8 6.4 0.5 127 3.3 

Site preparation 9 5.3 1.0 255 6.1 

Installation 29.7 17.5 1.4 357 8.5 

30 years of operation and 

maintenance ~ ---1:..i ....!L1. --ll 0.9 

Total for 30-year lifetime 286.9 168.9 16.5 4205 100.0 

III III 

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Table 2-7. Key Design Characteristics for the EPRI Flat 

Plate, One-Axis, Tracking Photovoltaic Central 

Station Design 

Time for construction: 

Peak capacity: 

Net peak plant output: 

Collector aperture: 

Number of panels: 

2 years 

97 MWe 

86 MWe (Southwest site) 

76 MWe (Southeast site) 

799,000 m2 

26,880 

TP-3772 

Array arrangement: North-South rows, horizontal axis with 

±50° rotation 

Structural concept: 

Nominal panel voltage: 

Torque tube, linear actuator 

60 VDC 

Nominal panel current: 63 A 

Laminate efficiency: 15% (at a cell temperature of 28°C) 

~ 

1.450 m 

1(4.760 ft) ----t· ... 1 

! ,fr " '::::::: 

'::::::: 

t : ':j, : :[:[\\\\\[: : :,:,:, M aintenance 

bu i1ding 

Substation 

'~ 2,13 

(6,9 

I=: 

Om 

I~ • 

.. ---I~ 90 ft) 

~ • 

~ ~ 

I i ~ 

Plant Layout 

• PCU (10 total) 

Subfield (10 total) 

- Security fencing 

--- Access road 

- AC collection cabing 

0 ffice/ 

ontrol 

uilding 

c 

b 

A 

N 

: : DC, bus disconnect cabinets (28 per subfield) 

Access road and 

34.5 kV cable corridor 

Corridor for direct 

buried DC cable 

Subfleld Layout 

Specifications 

Array area: 799,000 m2 

Land area: 765 acres 

NPOC: 86 MW SW; 76 MW SE 

Peak plant capacity: 97 MW 

Row orientation: N-S 

Row spacing: 8.1 m (26.7 ft) 

Row per subfield: 84 

Ground cover ratio: 0.30 

Figure 2-5. EPRI's plant arrangement for the one-axis, tracking, flatplate photovoltaic power plant (Source: Levy and Stoddard 

1984) 

15 
Fiqure 2-6. 

TP-3772 

Rotation ~ 

(± 50°C from § 

horizontal) ci: ,-0- m 

EPRX's one-axis, tracking, f1at-p1ate system structura1 

support concept (Source: Levy and Stoddard 1984) 

A fluidized-bed, coal-burning power plant was chosen as the fossil technology for comparison with the solar plants because it represents an 

advanced but state-of-the-art design that is economical and widely used. 

At present, coal is the predominant type of fossil fuel used for baseload 

electric power production in the United States, while oil and natural gas 

are used only for peaking load. Nuclear energy accounts for about 20% 

of the U.S. electric power production, or 7% of the total primary energy 

used in the United States (Energy Information Administration 1988). 

The numbers in the first column of Table 2-10 were calculated by multiplying the net annual output of the plant by the assumed lifetime. The 

second, third, and fourth columns are simply the total carbon dioxide 

produced during construction, operation and maintenance, and fossil-fuel 

burning, respectively, divided by the net lifetime energy output. In the 

last column, the total CO2 production per GWha from the three 

contributions is shown. 

For the solar technologies, the majority of carbon dioxide production 

occurs during construction. In contrast, 97% of the CO2 generated by the 

fluidized-bed coal-burning plant is produced during operation as a consequence of fossil-fuel combustion. All of the solar systems produce 

considerably less CO2 over a 30-year lifetime than the coal plant. The 

100-MWe solar thermal and photovoltaic systems produce only 4% and 3%, 

respectively, of CO2 per GWhe of that of the coal plant for a lifetime 

16 
Table 2-8. Cost, Embodied Energy, and CO2 Production of the Key Components of the 

EPRI Single-Axis, Tracking Photovoltaic System at the Southwest Site 

(Figures do not include tax, indirect costs, or contingency costs) 

System Components 

(Southwest site) 

Land 

Cost 

Estimate 

(10 4 $1982) 

Acquisition 153.0 

Site preparation 269.0 

Power conditioning system 746.9 

Foundation - electrical equipment 1.7 

Panel components (structural) 1,352.1 

Panel components (electrical) 408.7 

Panel assembly 1,050.8 

Pedestal (steel) 205.6 

Pedestal installation 453.6 

Panel installation 133.5 

DC field wiring 188.6 

DC system switchgear 412.9 

AC power system 97.8 

AC substation 115.0 

DC system station/tracking power 190.4 

Master control 140.0 

Buildings/enclosures 122.0 

Spare parts/equipment 37.7 

O&M equipment 29.0 

30 years of operation and 

maintainence 5,513.1 

Total for a 30-year lifetime 11,621.4 

Embodied Correcteda CO2 

Cost Energy (1977) Embodied Produced 

(10 4 $1977) (GWh) Energy (GWh) (metric tons) 

103.0 

181. 0 

502.7 

1.1 

910.0 

275.1 

707.2 

138.4 

305.3 

89.8 

126.9 

277.9 

65.8 

77.4 

128.1 

94.2 

82.1 

25.4 

19.5 

3,710.3 

7,821.2 

0.0 

16.4 

46.5 

0.3 

172 .2 

33.4 

88.1 

20.1 

38.6 

11.2 

21.4 

20.9 

12.3 

8.8 

18.8 

6.5 

7.7 

4.8 

2.0 

304.7 

834.7 

0.0 

12.7 

36.1 

0.2 

133.6 

25.9 

68.3 

15.6 

29.9 

8.7 

16.6 

16.2 

9.5 

6.8 

14.6 

5.0 

6.0 

3.8 

1.6 

236.3 

647.3 

o 

3,239 

9,191 

53 

34,034 

6,594 

17,414 

3,962 

7,621 

2,218 

4,225 

4,137 

2,422 

1,733 

3,717 

1,278 

1,529 

957 

403 

60,212 

164,939 

Per(:ent of 

Total CO2 

0.0 

2.0 

5.6 

0.0 

20.6 

4.0 

10.6 

2.4 

4.6 

1.3 

2.6 

2.5 

1.5 

1.1 

2.3 

0.8 

0.9 

0.6 

0.2 

36.5 

100.0 

aThese figures were corrected to reflect the 22.5% less energy needed per 1982 dollar of GNP at the 

beginning of 1989 than in 1977. 

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Table 2-9. Cost, Embodied Energy, and CO2 Production of the Key Components of the 

EPRi Single-Axis, Tracking Photovoltaic System at the Southeast Site 

(Figures do not include tax, indirect costs, or contingency costs) 

System Components 

(Southeast site) 

Land 

Cost 

Estimate 

(10 4 $1982) 

Acquisition 153.0 

Site preparation 296.0 

Power conditioning system 746.9 

Foundation - electrical equipment 1.4 

Panel components (structural) 1,352.1 

Panel components (electrical) 408.8 

Panel assembly 758.6 

Pedestal (steel) 174.2 

Pedestal installation 334.3 

Panel installation 105.2 

DC field wiring 188.5 

DC system switchgear 413.0 

AC power system 97. 7 

AC substation 115.0 

DC system station/tracking power 190.4 

Master control 140.0 

Buildings/enclosures 122.0 

Spare parts/equipment 37.4 

O&M equipment 29.0 

30 years of operation and 

maintainence 5,513.1 

Total for a 30-year lifetime 11,149.6 

Cost 

(10 4 $1977) 

103.0 

199.2 

502.7 

0.9 

910.0 

275.1 

510.5 

117.2 

225.0 

70.8 

126.9 

277.9 

65.8 

77.4 

128.1 

94.2 

82.1 

25.2 

19.5 

3,710.3 

7,521.9 

Embodied 

Energy 

(GWh) 

0.0 

16.3 

46.5 

0.2 

172 .2 

33.4 

63.3 

17.0 

28.4 

8.8 

21.4 

21.0 

12.3 

8.8 

18.8 

6.5 

7.7 

4.8 

2.0 

304.7 

794.1 

Correcteda CO2 

Embodied Produced 

Energy (GWh) (metric tons) 

0.0 

12.6 

36.1 

0.2 

133.6 

25.9 

49.1 

13.2 

22.1 

6.8 

16.6 

16.3 

9.5 

6.8 

14.6 

5.0 

6.0 

3.7 

1.6 

236.3 

616.0 

o 

3,215 

9,191 

41 

34,034 

6,594 

12,500 

3,361 

5,620 

1,745 

4,225 

4,143 

2,428 

1,733 

3,717 

1,278 

1,529 

951 

403 

60,212 

156,922 

Percent of 

Total CO2 

0.0 

2.0 

5.7 

0.0 

21.8 

4.2 

8.0 

2.1 

3.6 

1.1 

2.6 

2.6 

1.5 

1.1 

2.3 

0.8 

1.0 

0.6 

0.3 

38.4 

100.0 

aFigures were corrected to reflect the 22.5% less energy needed per 1982 dollar of GNP in the beginning of 

1989 than in 1977. 

III 

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Table 2-10. Net Lifetime Energy Output and CO2 Production per GWh. for Electric Power Plants with a 

30-Year Lifetime 

Technology 

Net Lifetime CO2 Contribution 

Energy Output from Construction 

(102 GWhe ) (metric tons/GWhe ) 

Battelle 100-MW. Molten 105.0 31 

Salt Central Receiver 

Austin 300-kWe PV System 0.15 277 

EPRI 100-MWe PV System 

Southwest site ·68.4 15 

Southeast site 53.4 18 

Fluidized-bed coal -1075.0 5 

CO2 Contribution 

from Operation 

and Maintenance 

(metric tons/GWhe ) 

12 

3 

9 

11 

28 

CO2 Contribution 

from Fossil Fuel 

Input 

(metric tons/GWhe ) 

1008 

Total CO2 

Production 

(metric tons/GWhe ) 

43 

280 

24 

29 

1041 

III 

III 

~ 

1*1 • 
1100 

m 900 ..c 

s: 

(9 800 --(/) 

c 

....... 0 700 

0 .;;:: 

Q) 600 

E 

c 500 

0 

U 400 ::J 

"0 

e 300 

a. 

C\J 

0 200 

0 

0 

Figure 2-7. 

Fluidized-bed 

coal plant 

rz:d Plant construction 

Q Operation and maintenance 

~ Fuel combustion 

1 OO-MWe solar 1 OO-MW e 

thermal plant photovoltaic 

plant-SE site 

100-MWe 

photovoltaic 

plant-SW site 

TP-3772 

Total CO2 production per GWh. of output energy. CO2 

production for the coal plant is due primarily to fuel 

combustion. For the solar plants, CO2 is produced 

primarily during construction of the plant. 

of 30 years. Substituting advanced natural gas systems for coal can 

reduce the CO2 production up to 50% (Morrison 1989). But this reduction 

would come with a considerable increase in cost and without achieving a 

long-term solution to global warming. However, substituting solar technology in favorable solar climates for coal-fired power plants could 

over time reduce CO2 generation. For example, if a solar thermal or 

photovoltaic power plant were built instead of a coal-fired unit, CO2 

production during the first 30 years of operation of the solar plant 

would be less than 5% of that of the baseline coal plant. Moreover, 

once solar technology is in place on a large scale, it could become a 

"solar energy breeder." In other words, part of the energy it produced 

could be used to build more power plants and eventually eliminate global 

warming caused by electric power generation (Grimmer 1981). 

The CO2 production per unit energy for the City of Austin's 300-kWe photovoltaic plant is considerably greater than that for the EPRI 100-MWe 

photovoltaic plant designs. This shows the significance of economies 

of scale and suggests caution in using the data for a small, firstgeneration system to determine the viability of a technology. The difference in the results for the EPRI photovoltaic designs located in the 

Southwest site and those for the less favorable Southeast site is only 

20%. This indicates that renewable energy systems will produce electric 

20 
TP-3772 

power with considerably less CO2 generation than fossil systems even at 

less favorable solar sites. 

2.5 The Potential of Cogeneration for Reducing CO2 Production 

The combined generation of heat and power, generally called cogeneration, 

is a cost-effective, reliable method for increasing the overall efficiency of fuel utilization (Horlock 1987). The most widely used method 

of combining the generation of heat and power uses the heat rejected from 

a turbine to supply thermal energy for an industrial process or for heating and cooling of buildings. Since with the same hardware more energy 

is produced per unit of fossil energy used, the CO2 production per unit 

output of energy can be reduced by using cogeneration. Two cycles that 

could be applied to a fluidized-bed coal system as well as to a solar 

thermal central-receiver system are the extraction condensing cycle and 

the back-pressure cycle shown schematically in Figure 2-8. Cogeneration 

can also be applied to solar energy conversion systems. Extensive conceptual design studies of solar thermal cogeneration systems have been 

conducted by Sandia National Laboratories (1982). These studies have 

shown that for a given energy output, cogeneration systems require less 

collector or heliostat area than two separate systems (one for heat and 

the other for power). In principle, cogeneration can also be used with 

photovoltaic power systems, but the thermal output is too low in temperature to be thermodynamically useful. 

Extraction 

condensing 

plant 

Back pressure 

plant 

e 

~ 0.40 

B = Boiler ~ 

T = Turbine § e = Generator ..( 

/NIl. = Heat exchanger <Xl 

W = Work 

Q = Heat (useful) 

F = Fuel energy potential 

Figure 2-8. Schematic diagrams of combined heat (~) and electricity 

(W) cogeneration systems (Source: Horlock 1987) 

21 
TP-3772 

The potential reduction in CO2 achievable with a cogeneration system over 

separate heat and electricity systems with the same output is shown in 

Table 2-11. Since CO2 production for a given power plant with a given 

lifetime is proportional to the energy output of the plant, the reduction 

in CO2 production due to cogeneration is directly proportional to the 

energy savings. The potential reduction in CO2 production achieved by 

cogeneration, shown in the last column of Table 2-11, is thus simply the 

difference between the sum of the energy requirements of the separate 

systems and the cogeneration system divided by the energy requirement of 

the separate systems. We see that 29% less CO2 is produced by a backpressure cogeneration system than that produced by two separate systems 

with the same heat and power rating. 

22 
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Table 2-11. Potential for Reducing CO2 by Using Cogeneration System,t[S 

(see Figure 2-8) 

Cogeneration 

System 

Thermal Output per 

Unit Thermal Input 

(kWht/kWht ) 

Extracting condensing 

system 

0.10 

Back-pressure system 0.60 

Electrical Output 

per Unit Thermal 

Input (kWhe/kWht ) 

0.38 

0.25 

Ratio of Thermal 

Input for Two 

Separate SYstems 

to That for a 

Cogeneration System 

(kWh),/ (kWh) CG a 

1.06 

1.2~ 

Potential Reduction in CO2 

~~oduction by 

G9generation 

6% 

29% 

a (kWh)s = Thermal input to the separate systems with the same output as the cogeneratipn systems. 

(kWh)CG = Thermal input to the cogeneration system. 

Calculations are based on system efficiencies of 90% for the thermal system and 40% fQ~ the 

electrical system. 

UI 

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3.0 DXSCUSSXON 

This report compares CO2 production per unit energy output during a 

30-year lifetime from a fluidized-bed, coal-fired power plant, a small 

and a large solar photovoltaic plant, and a solar thermal centralreceiver power plant. The approach used in making these calculations 

starts with an energy analysis that accounts for the energy embodied in 

all of the components of the plants, the energy required fox the 

operation and maintenance of the plants, and the fossil-fuel energy used 

to operate them. The method uses an input/output table that shows the 

monetary flows into and out of all sectors in the U.S. national economy. 

To convert the monetary costs of the components, labor, and fuel to 

energy units in this approach, one attaches energy flows, which can be 

obtained from a national energy balance, to the monetary flows in an 

input/output table. Then, a matrix based on the energy flows and their 

respective monetary values can be formulated, as shown by Hannon et ale 

(1981) . This energy consumption matrix reveals the amount of primary 

energy (including all energy expenditures) necessary to produce one unit 

of monetary value in a given economic sector of the input/qutput matrix. 

Conventional net energy analysis has been widely used as a supplement 

to standard economic analyses based on a monetary assessment of cost and 

benefits (Spreng 1988). It takes into account not only direct energy 

consumption but also the indirect energy consumption involved in the 

totality of an economic system. Once we know the energy input for the 

construction, operation, and maintenance of a system during its 30-year 

lifetime, we can calculate the CO2 production. 

An analysis of CO2 production from several energy technology systems has 

also been performed recently by a DOE contractor (Meridian Corporation 

1989). The approach Meridian used was a process chain analysis. As the 

name implies, a complex production chain is broken into its various 

steps, and for each step the relevant energy inputs and outputs are identified and evaluated. At the end of this chain is the physical system 

in which all the energy expenses have been accumulated. Then, the energy 

required to operate the system during its lifetime is added to that 

required to construct it, and the total energy during 30 years of power 

production is obtained. San Martin (1989) states that this approach 

views "the environmental effects of energy production at all stages of 

the energy production cycle as a direct function of generating the final 

energy product," and that "by analyzing the complete cycle these effects 

can be fully and consistently evaluated. . .. By investigating the 

impact of each stage of the energy production process the analysis 

attempts to normalize the differences between material- and fuelintensive technologies to provide a fair basis for comparison." 

Both the approach used in this report and the process chain approach 

have advantages and disadvantages. The latter estimates the CO2 emissions 

associated with each stage of energy production, from fuel extraction 

through construction, operation, and decommissioning, as part of a system 

designed to produce energy. The advantage of 'this approach is that current methods of operation in each step of the process can be fed directly 

into the process chain during the analysis. The disadvantage, however, 

is that it is not only tedious but also extremely difficult to include 

24 
all the steps in the process chain. 

consuming and expensive to perform. 

TP-3772 

The analysis is also very timeThe advantage of the approach used in this report is that it is relatively simple, and it automatically encompasses all the functions of the 

U.S. economy. The disadvantage is that the last comprehensive energy 

matrix converting from monetary to energy units was prepared in 1985 

using the Bureau of Economic Analysis input/output data for 1977, and 

its accuracy has not been demonstrated quantitatively. Also, it is 

necessary to correct the embodied energy for the increase in energy 

efficiency of the U.S. economy between 1977 and 1989 to estimate the 

energy embodied in a plant built in 1989. This correction can be 

obtained from the yearly statistics about energy use and GNP on a SIC 

basis, but it does not reveal detailed shifts in the energy consumption 

pattern, such as, for example, the increase in imports of energyintensive products. 

A comparison of our results and those of other studies (Meridian Corporation 1989; San Martin 1989) reveals essential agreement for the fossil 

system, but some substantial differences in the CO2 production predicted 

for the solar energy systems. The results are displayed in Table 3-1 for 

an assumed lifetime of 30 years. We see that there is essential 

agreement between the results for the coal-fired power plant and that all 

the studies indicate that renewable energy sources, be they photovoltaic 

or solar thermal, will produce per unit output less than 5% of the CO2 

generated by the coal plant during their lifetimes. However, our results 

predict larger CO2 production for the renewables than the DOE study, even 

after the 22.5% correction for the efficiency increase is applied. A 

reason for this difference may be that in Meridian's study, which does 

not show the intermediate steps in the process chain, some steps have 

been omitted. Moreover, only the CO2 production associated with the 

aluminum, glass, steel, and concrete in the power plants is included 

(Meridian 1989). All other energy inputs, including labor, are omitted 

because of a lack of available information on the process requirements. 

This could be a serious omission, since our analysis, as shown in 

Table A-10 in the appenix, indicates that 55% of the primary energy 

required to construct a photovoltaic plant comes from materials that are 

not included in the chain analysis. Since the majority of CO2 production 

from the renewable plants occurs during construction, a simplified chain 

analysis leads to a significant underestimation of the total CO2 

production for all renewable energy systems. Moreover, energy 

expenditures for operation and maintenance in solar thermal and 

photovoltaic plants have also been omitted. 

A net energy analysis for the major materials contents of a 100-MWe solar 

thermal power plant has also been conducted by Vant-Hull (1988), who 

used a process chain method approach. However, he used stretchedmembrane heliostats and included only the thermal part of the plant. 

Vant-Hull estimated that 372 GWh of energy are embodied in the material 

used to construct that system. Our analysis indicated that the construction of the thermal portion of the central-receiver plant, using glass 

heliostats, would require about 1061 GWh of primary energy. The discrepancy seems largely due to the difference in heliostat technology and 

Vant-Hull's analysis having omitted the energy costs of labor and the 

control system. 

25 
N 

0') 

Table 3-1. Comparison of CO2 Production per GWh. Net Lifetime Energy Output for 

Various Electric Power Technologies (metric tons of CO2 ) 

DOE DOE Kreith and Nortona 

System (Meridian Corporation 1989) (San Martin 1989) (1989) 

Fluidized-bed coal 1059 963 

Oil-fired plant 726 937 

Gas-fired plant 484 687 

Boiling water reactor 9 8 

Wind energy 7 47 

Photovo1taics 6 5 

Solar thermal 4 

This Study 

1041 

24 

43 

GThe data presented earlier by Kreith and Norton (1989) were modified to reflect CO2 production 

from fossil fuels from the DOE studies (Marland and Rotty 1983) and the increased energy 

efficiency of the U.S. economy between 1977 and 1988. 

UI 

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TP-3772 

The CO2 production due to construction of the solar thermal electric 

power plant, using Vant-Hull's analysis and assuming an embodied energy 

in the electric conversion and balance of plant equal to that in our 

analysis, is 18 metric tons of CO2 per GWhe • This is about 58% of the 

31 metric tons of CO2 per GWhe CO2 production due to construction estimated 

in this study. If glass heliostats were used and labor energy cost were 

included, Vant-Hull's CO2 production estimate would be of the same order 

of magnitude as that of this study. 

The estimation of annual operation and maintenance costs of solar thermal 

power plants is uncertain, as illustrated by the estimates ranging from 

$1.00 to $17.30/m2 ($1984) presented by various sources (Williams et al. 

1987). The data base for the solar thermal power plant analyzed in this 

paper includes an anImal operation and maintenance cost of $5.17 1m2 

($1984). The CO2 production due to operation and maintenance is thus 

12 metric tons of C02 /GWhe , bringing the total CO2 production from the 

plant to 43 metric tons of C02 /GWhe • 

It is important to note that CO2 production from nuclear and solar systems 

is of the same order of magnitude, according to the chain analysis of 

San Martin (1989). Recently, interest has been renewed in building more 

nuclear power plants in the United States, and reducing CO2 emissions has 

been given as a reason for shifting from coal to nuclear power. Europe's 

experiences have demonstrated that nuclear power is a viable option, but 

the costs of dismantling obsolete plants and disposing of radioactive 

waste remain unresolved problems. Moreover, after the accidents at Three 

Mile Island and Chernobyl, public fears understandably cloud the nuclear 

option in the United States, although it is available. 

27 
4 . 0 IMPLICATIONS FOR A NATIONAL ENERGY POLICY 

Although there are discrepancies in the details, the basic agreement 

between our analyses and others (Meridian 1989; San Martin 1989; VantHull 1989) is sufficient from a broad policy perspective. The re~ults 

of all these studies show that any serious efforts to reduce CO2 production from· electric power plants would require a major shift from 

fossil fuels to renewable energy sources. The use of cogeneration and 

fossil-fuel switching from coal to natural gas may be helpful in ameliorating CO2 production in the short run, but they cannot solve the global 

warming problem in the long term. 

The approach for calculating greenhouse-gas emissions illustrated in this 

_ report for electric power production and in an earlier paper for wind 

energy, passive solar, and water heating (Kreith & Norton 1989) could 

of course also be applied to conservation and other energy production 

technologies. We have made some preliminary calculations based on a 

previous study by Pilati (1977), and the results indicate that for the 

short term the most effective way to reduce CO2 production is by introducing conservation measures that reduce energy requirements, rather 

than by increasing energy production to meet increased energy demands. 

Japan today produces a dollar's worth of GNP for less than half the 

primary energy input required by the U.S. economy (International Energy 

Agency 1987). Consequently, a desirable first step in a long-term energy 

plan would be to improve the energy efficiency of the United States by 

introducing energy conservation and mature renewables while continuing 

to develop new types of these plants to improve their efficiency and 

reduce their cost. 

As illustrated in this report, once the net energy analysis for an energy 

generation or conservation system has been performed, it is a simple 

matter to calculate its lifetime CO2 production. From this information 

it is then possible to estimate with existing and developing computer 

simulation models the social costs (Hohmeyer 1988) or the extent of 

global warming that different policies would create (Jaeger 1988). We 

have shown in this report that energy conservation measures and shifting 

from fossil to renewable energy sources offer significant long-term 

potential to reduce CO2 production caused by energy generation. Many of 

these CO2 reduction measures can be justified on their own merits, irrespective of their possible effect on reducing global warming (Schneider 

1989). In view of the long lead time required for conservation and renewable technologies to be brought into the energy infrastructure on a large 

scale, policies that can be justified on their own merit and also reduce 

greenhouse-gas emissions should be initiated as soon as possible. There 

is a risk in delaying such actions since the costs of reducing CO2 emissions are likely to increase if the urgency for their implementation 

should grow. 

28 
S5~1'_' TP-3772 

5 . 0 REFERENCES 

Alpert, D. J., and R. M. Houser, 1989, "Evaluation of the Optical Performance of a Prototype Stretched Membrane Mirror Module for Solar 

Central Receivers," J. Sol. En. Eng., 111:37-43. 

Bath, T. D., and D. L. Feucht, 1990, "Renewable Energy as a Response to 

Glopal Warming Concerns," Greenhouse Mitigation, A.E.S. Green, ed., 

American Society of Mechanical Engineers, FACT, Vol. 7. 

Brown, D. R., 1988, "Cost Drivers for Solar Thermal Central Receiver 

Power Plants," J. Sol. En. Eng., 110:156-164. 

Energy Information Administration, 1988, Monthly Energy Review, U. S. 

Department of Energy, Washington, DC, December. 

Grimmer, D. P., 1981, "Solar Energy Breeders," Solar Energy, 26:49-53. 

Hannon, B., R. A. Herendeen, and T. S. Blazeck, 1981, Energy and Labor 

Intensities for 1972, Energy Research Group, University of Illinois 

at Urbana-Champaign .. 

Hannon, B., S. P. Caster, and T. S. B1azeck, 1985, Energy Intensities for 

the U.S. Economy-1977, Energy Research Group, University of Illinois 

at Urbana-Champaign. 

Hoffner, J. E., 1989, "Analysis of the 1988 Performance of Austin's 

300-kilowatt Photovoltaic Plant," Proceedings of the 1989 Conference 

of the American Solar Energy Society, Denver, Colorado. 

Hohmeyer, 0., 1988, Social Costs of Energy Consumption, Springer-Verlag, 

Berlin, West Germany. 

Horlock, J. H., 1987, Cogeneration: Combined Heat and Power, Pergamon 

Press, Oxford, England. 

Houghton, R. A., and G. M. Woodwell, 1989, "Global Climatic Change," 

Scientific American, 260:36-44, April. 

International Energy Agency, 1987, "Energy Conservation in 

Countries," Paris: Organization for Economic Operation 

Development. 

lEA 

and 

Jaeger, J., 1988, "Developing Policies for Responding to Climatic 

Change," WMO/TD-No. 225, Beijer Institute, Stockholm, Sweden. 

Ke r r, R. A., 198 9 , 

245:1330-3331. 

"Oil and Gas Estimates Plummet," Science, 

Kreith, F., and P. Norton, 1989, "The Potential of Solar Technologies to 

Reduce the Greenhouse Effect," Proceedings of the 1989 Annual Conference of the American Solar Energy Society, M. 1. Coleman, ed., 

pp. 385-391, Denver, CO. 

29 
TP-3772 

Kreith, F., R. E. West, and C. J. Cleveland, 1987, "Energy Analysis for 

Renewable Energy Technologies," ASHRAE Trans., 91:999-1010. 

Levy, S. L., and L. E. Stoddard, 1984, Integrated Photovoltaic Central 

Station Conceptual Designs, EPRI AP-3264, .Electric Power Research 

Institute, Palo Alto, CA. 

Lovins, A. B., L. H. Lovins, F. Krause, and W. Bach, 1981, Least-Cost 

Energy, Solving the C~ Problem, Brick House Publishing, Andover, 

MA. 

Mackenzie, J. J. 1988, Breathing Easier: Taking Action on Climate Change, 

Air Pollution, and Energy Insecurity, World Resources Institute, 

Washington, DC. 

Mann, G., and B. Neenan, 1982, Economic Profiles of Selected Solar Energy 

Technologies for Use in Input-Output Analysis, LA-9083-TAES, Los 

Alamos National Laboratory, Los Alamos, NM. 

Marland, G., and R. M. Rotty, 1983, Carbon Dioxide Emissions from Fossil 

Fuels: A Procedure for Estimation and Results for 1950-1981, DOE/NBB0036, Oak Ridge, TN: Oak Ridge Associated Universities. 

Meridian Corporation, 1989, Energy Systems and Material Requirements, 

prepared for the U. S. Department of Energy Office of Renewable 

Energy, Washington, DC, February. 

Morrison, R. E., .1989, Global Climate Change, Congressional Research 

Service, Library of Congress, Washington, DC, Order Code IB 81005. 

Murphy, L. M., 1986, "Stretched Membrane Heliostat Technology," J. Sol. 

En. Eng., 108:230-238. 

Nierenberg, W. A., 1989, "Atmospheric CO2 : Causes, Effects, and 

Options," Chem. Eng. Prog., 85:27-36. 

Panico, D., 1989, private communication, City of Austin Electric Utility 

Department. 

Perry,. A. M., et al., 1977, Net Energy Analysis of Five Energy Systems, 

ORAV/IEA(R) -77-12, Oak Ridge, TN: Oak Ridge Associated Universities. 

Pilati, P. A., 1977, "Energy Analysis of Electricity Supply and Energy 

Conservation Options," Energy, 2:1-7. 

Ramanathan, V., 1988, "Greenhouse Theory of Climate Change," Science, 

240:293-299. 

Rockwell International, 1983, Preliminary Design of the Carrisa Plains 

Solar Central Receiver Power Plant, ESG-DOE-13404, Rockwell International, Inc., Canoga Park, CA. 

Sandia National Laboratories, 1982, Solar Cogeneration, Livermore, CA, 

April. 

30 
TP-3772 

San Martin, R. L., 1989, Environmental Emissions from Energy Technology 

Systems: The Total Fuel Cycle, U.S. Department of Energy, Washington, 

DC, April. 

Schneider, S. H., 1989a, "The Greenhouse Effect: Science and Public 

Policy," Science, 243:771-780, February. 

Schneider, S. H., 1989b, "The Changing Climate," Scientific American, 

261:70-79, September. 

Spreng, D. T., 1988, Net Energy Analysis and the Energy Requirements of 

Energy Systems, Praeger Publishers, New York, NY. 

U.S. Department of Energy, 1985, Solar Thermal Technology,' Annual Evaluation Report, Fiscal Year 1984, Solar Technical Information Program, 

Washington, DC, June. 

Vant-Hull, L. L., 1988, "Solar Thermal Electricity, An Environmentally 

Benign and Viable Alternative," Energy and The Environment Conference, Denver, CO, September. 

Weber, E. R., 1983, Preliminary Design of a Solar Central Receiver for 

a Site-Specific Repowering Application (Saguaro Power Plant), 

DOE/SF/11675-T1, Arizona Public Service Company, Phoenix, AZ. 

west, R. E., 1988, "Inflation Adjustment," in Economic Analysis of Solar 

Thermal Systems, R. E. West and F. Kreith, eds., MIT Press, 

Cambridge, MA. 

Williams, T. A., et al., 1987, Characterization of Solar Thermal Concepts 

for Electricity Generation, PNL-6128, Pacific Northwest Laboratory, 

Richland, WA. 

31 
APPENDIX 

Component Costs for Mo1ten-Sa1t Centra1 Receiver 

and Photovo1taic Systems 

TP-3772 

In this appendix, the costs and/or material requirements for a 100-MWe 

molten-salt central receiver system, a 300-kWe photovoltaic system, and 

a 10Q-MWe photovoltaic power plant are itemized. 

All cost data for the central receiver are in 1984 dollars and represent 

direct costs for equipment, material, and labor. Total capital costs 

were estimated by adding an additional 25% for indirect costs and 10% for 

contingency (indirect and contingency = 35% of the direct cost). Indirect costs represent expenses for temporary construction facilities, 

field supervision, management, clerical services, equipment rental, engineering, construction fee, and other cost elements not directly related 

to the construction of any single piece of equipment. The detailed cost 

and material figures documented in Tables A-1 through A-8 were developed 

from one design point of the system evaluated in a report by Williams 

et al. (1987). Specific design and annual performance data are summarized in Table 2-3 of the report. 

The costs and material requirements for the City of Austin's 300-kW 

photovoltaicsystem are itemized in Table A-9. The itemization of the 

components and their integration into standard industrial code (SIC) 

sectors was provided by D. Panico (1989) of the City of Austin Electric 

Utilities Department. The actual costs are presented in Table A-9 along 

with the costs deflated to 1977 dollars and the embodied energy. 

The construction details and costs of a 100-MWe, single-axis tracking, 

flat-plate photovoltaic system were analyzed for two sites-one in the 

southwestern United States (Barstow, Calif.) and another in the southeastern United States (Bay Minette, Ala.)-by EPRI in 1984. Table A-10 

shows the cost estimates in 1982 dollars and deflated to 1977 dollars, 

the appropriate SIC sector, the energy intensity, and the embodied energy 

for the components of the southwestern system. The same details are 

shown in Table A-11 for the southeastern location. 

32 
Tabl.e A-l.. Receiver Component Costs and Weights of Material. 

for the Sol.ar Thermal. System (Receiver shop and 

field labor = 265,000 manhours) 

Components 

Absorber 

Structure 

Circulation 

Instrumentation and control 

Total installed cost 

Mate,rial 

Absorber tubes (Incoloy 800H) 

Misc. piping (50% carbon steel, 

50% stainless steel) 

Surge tanks (1 carbon steel, 1 

stainless steel) 

Structural steel 

Misc. steel 

Insulation 

Molten salt 

Miscellaneous items 

Cost 

($1984) 

11,926,000 

3,148,000 

1,533,000 

1, 243,000 

$17,850,000 

Weight (lb) 

143,600 

143,600 

143,600 

861,600 

143,600 

143,600 

287,200 

143,600 

Tabl.e A-2. Tower Component Costs for the Sol.ar Ther.mal. System 

(Installation labor = 90,000 hours) 

Components 

Accessories 

(elevator, lighting, stairs, ladders, 

lightening protection, and platforms) 

Concrete and rebar 

(concrete volume = 18,000 cubic yards, 

rebar weight = 900 tons) 

Total installed cost 

33 

Cost 

($1984 ) 

430,000 

5,419,000 

$5,849,000 

TP-3772 
Tabl.e A-3. 

Component 

Mirror module 

Support structure 

(all steel except 

the paint) 

Pedestal 

Drive unit 

Controls and 

wiring 

Transportation 

Site assembly 

building overhead 

Bel.iostat Material. Cost for the Sol.ar 

Thermal. System (Labor = 92 hours per 

heliostat) 

Materials 

1600 ft 2 of thin, low iron fusion glass 

with silver and copper coatings 

1600 ft2 of polyvinyl butylate adhesive 

1600 ft 2 of float glass 

118 lb of glass/metal "contact cement" 

3063 lb of steel hat sections 

281 lb of steel braces 

56 lb of bolts 

1207 lb of truss chords 

275 lb of truss tubing 

860 lb of truss bracing 

1924 lb of torque tubes 

238 lb of torque tube brackets 

77 lb of torque tube flanges 

36 lb of bolts 

2 gal. of paint 

3464 lb steel pipe 

91 lb steel flange 

2 gal. of paint 

Primarily built from steel materials 

Heliostat control 

Power and control cabling 

Array control 

Beam characterization 

600 miles via semi-truck and trailer 

sheet 

TP-3772 

Cost 

($1984) 

1496 

479 

698 

491 

764 

70 

50 

376 

86 

268 

600 

74 

37 

65 

42 

1080 

40 

36 

1500 

265 

465 

51 

20 

394 

264 

Note: The direct material and labor requirements listed are for a 

single heliostat and must be multiplied by 4932, the number of 

heliostats in the reference system. The total installed cost is 

$73,300,000, which includes all overheads and profits associated 

with heliostat manufacturing. 

The total manufacturing plant capital equipment cost is 1.9 X 107 

$1984. . 

34 
Table A-4. Transport System Material Costs for 

the Solar Thermal System 

(Labor hours = 188,000) 

Material 

Heat tracing 

Carbon steel pipe 

Stainless steel pipe 

Carbon steel pump 

Expansion joints 

Ground support 

Carbon steel and stainless steel fittings 

Carbon steel and stainless steel valves 

Stainless steel valves insulation 

Total installed cost 

Cost 

($1984 ) 

184,000 

95,000 

812,000 

2,301,000 

619,000 

11,000 

100,000 

144,000 

785,000 

$5,052,000 

Table A-S. Storage System Component Costs for 

the Solar Thermal System 

Component 

Molten salt (23.7 E6 lb) 

Carbon steel tanks 

Concrete foundation 

Insulating brick 

Nickel alloy liner 

Insulation 

Aluminum siding 

Carbon steel pipe 

Stainless steel pipe 

Installed Cost 

($1984) 

5,291,000 

943,000 

1,151,000 

971,000 

854,000 

1,134,000 

Carbon steel and stainless steel fittings 

Heat tracing 

51,000 

214,000 

747,000 

480,000 

201,000 

Pipe supports 

Carbon steel and stainless steel valves 

Conveyor and storage bins 

Misc. piping 

Melting tank and heater 

Sump. and drain 

Instrumentation and control 

Misc. equipment 

Total installed cost35 

19,000 

1,386,000 

582,000 

338,000 

516,000 

520,000 

538,000 

55,000 

$15,990,000 
Tab1e A-6. Energy Conversion System Component Costs 

for the So1ar Therma1 System 

Components 

Turbine~generator 

Cooling tower, condenser, and 

ancillary rankine cycle equipment 

Carbon steel preheater (10,680 ft2) 

Low-alloy steel evaporator (12,980 ft2) 

Stainless steel superheater (6,930 ft2) 

Stainless steel reheater (5,650 ft2) 

Total installed cost 

Installed Cost 

($1984) 

15,500,000. 

15,500,000 

1,150,000 

2,350,000 

2,030,000 

1,790,000 

$38,320,000 

Tab1e A-7. Ba1ance-of-P1ant Costs for the So1ar 

Therma1 System 

Cost Element 

Land (1055 acres) 

Purchase and permits 

Survey, clear and grub, grade, 

roads, ditches (mostly labor and 

equipment rental) 

Structures (control room, administrative 

offices, maintenance shop, warehouse, 

and fencing) 

Master control 

Spare parts 

Power conditioning 

Service facilities 

Vehicles 

Communications 

Protection systems (fire, security) 

Water supply 

Feedwater treatment 

Total installed cost 

36 

Installed Cost 

($1984) 

5,589,000 

9,686,000 

834,000 

2,636,000 

2,944,000 

2,814,000 

324,000 

22,000 

150,000 

110,000 

638,000 

$25,747,000 
Tab1e A-B. Operation and Maintenance Costs for 

the So1ar Therma1 System 

Cost Element 

Direct production (all labor) 

Direct maintenance (labor and materials) 

Plant overhead (mostly labor) 

Molten salt replacement (mostly material) 

Total annual O&M cost 

37 

Cost 

($1984) 

619,000 

2,560,000 

477,000 

134,000 

$3,790,000 
w 

co 

Table A-g. Cost and Embodied Energy of the City of Austin's 300-kW Photovoltaic Plant 

Actual Cost Cost 

PV300 Plant Component Qty/Unit ($1986) ($1977) 

Photovoltaic Panels 

Solar cells 

Encapsulation 

Freight 

28190 ft2 

58212 lbs. 

lot 

Power Conditioning Unit 

Inverter 1 ea. 

1 ea. 

1 ea. 

Transformer 

AC switchgear 

Field engineering 

Freight 

Structural Subsystem 

Concrete 

Steel sup. struct. 

Metal bldg. 

Rebar 

Bearings 

Electrical Subsystem 

21 days 

lot 

66792 lb 

114380 lb 

704 ft2 

227534 lb 

154 ea. 

Conduit, steel & PVC 2500 ft. 

Wire, copper 1690 lb 

Misc. electrical lot 

Nonessential 

Lavatory 

Water line 

Sewer line 

Remote control line 

Site Preparation 

1 ea. 

1000 ft 

1000 ft 

700 ft 

Clearing and grading lot 

Gravel 6270264 lb 

Paved road 463820 lb 

Installation 

Design/Proj. Management 

Administration 

1595089 

76846 

3200 

168630 

24900 

20560 

12120 

7190 

125000 

107000 

20000 

10000 

8000 

39455 

8565 

59980 

26500 

19800 

35822 

25878 

16780 

47020 

26200 

297000 

198000 

120000 

939188 

45247 

1884 

99289 

14661 

12106 

7490 

4233 

73600 

63002 

11776 

5888 

4710 

23231 

5043 

35316 

15603 

11658 

21092 

15237 

9880 

27685 

15427 

174874 

116582 

70656 

SIC Sector 

Semiconductors 

Glass 

Motor freight trans. 

Electrical equip. 

Transformer 

Switchgear 

New Construction 

Motor freight trans. 

Cement 

Fab struc. steel 

Fab struc. steel 

Iron, stl. foundries 

Bearings 

Pipe 

Fab. wire products 

Electrical equip. 

Plumbing fixtures 

NCNST water 

NCNST sewer 

NCST elec. util. 

Const. machinery 

Stone 

Asphalt 

New construction 

SIC Code 

570200 

350100 

650300 

580500 

530200 

530300 

110250 

650300 

360100 

400400 

400400 

370200 

490200 

420800 

420500 

580500 

360600 

110306 

110307 

110303 

450100 

361500 

310300 

110250 

Energy 

Intensity 

(Btu/$1977) 

29749 

58274 

29196 

38118 

42591 

25728 

35535 

29196 

216613 

49469 

49469 

48498 

42638 

37637 

71355 

38118 

60670 

30950 

27520 

30648 

34534 

39667 

184121 

Embodied 

Energy 

(lOs Btu) 

279.4 

26.4 

0.6 

37.8 

6.2 

3.1 

2.7 

1.2 

159.4 

31.2 

5.8 

2.9 

2.0 

8.7 

3.6 

13.5 

9.5 

3.6 

5.8 

4.7 

3.4 

11. 0 

28.4 

35535 62.1 

0.0 

0.0 

Total Embodied Energy 7.13 X 1010 Btu 

(21 Gh'h) 

III 

III 

N 

-

If

-~ 

I I 

< - ' 
III 

III 

Table A-I0. Cost and Embodied Energy of the EPlU Single-Axis Tracking Photovoltaic AI 

System at the Southwest Site -

" I I 

EPRI One-Axis Tracking Cost Energy Embodied "-" 

System Components Estimate Cost Intensity Energy 

(Southwest site) ($1982) ($1977) SIC Sector SIC Code (Btu/$1977) (109 Btu) 

Land 

Acquisition 1530000 1029690 

Site preparation 2690000 1810370 NCST Elec. Util. 110303 30648 55.48 

Power Conditioning System 7469000 5026637 Power trans. equip. 490500 31569 158.69 

Foundation - Elec. Sys. 17100 11508 Ready-mix concrete 361200 80909 0.93 

Panel Compo (structural) 

Gasket tape 698880 470346 Misc. plastics 320400 63281 29.76 

Torque tube 4139520 2785897 Fab. struc. steel 400400 49469 137.82 

Torque tube pedestal conn'n 3198720 2152739 Steel prod. 370100 115724 249.12 

Linear actuator 833280 560797 General indo mach. 490700 28793 16.15 

Cross members 1263360 ~50241 tab. struc. steel 400400 49469 42.06 

Longitudinal and center members, 

w keeper bars, fasteners 3386880 2279370 Fab. struc. steel 400400 49469 112.76 ~ Panel Compo (elect. ) 

Nylon 12 chutes 96768 65125 Misc. plastics 320400 63281 4.12 

Busbar 1567104 1054661 Wiring devices 550300 40586 42.80 

Bypass diode/heat sink 2150400 1447219 Electronic compo 570300 31502 45.59 

Cover plate 274176 184520 Steel prod. 370100 115724 21.35 

Panel Assembly 

Labor 10059410 6769983 NCST non. bldg. 110704 43107 291. 83 

Equipment 421600 283737 General indo mach. 490700 28793 8.17 

vehicles 28000 18844 Motor veh. & parts 590300 35846 0.68 

Pedestal (steel) 2056320 1383903 Fab. struc. steel 400-400 49469 68.46 

Pedestal Installation 

Surveying (labor) 214500 144359 NCST non. bldg. 110704 43107 6.22 

Auger holes (labor) 3089164 1406007 NCST non. bldg. 110704 43107 60.61 

Place concrete (labor) 1183812 796705 NCST non. bldg. 110704 43107 34.34 

Place and align. pedestal 1018164 685224 NCST non. bldg. 110704 43107 29.54 

Pedestal tests 30000 20190 NCST non. bldg. 110704 43107 0.87 

Panel Installation (labor) 1247600 839635 NCST non. bldg. 110704 43107 36.19 1-'3 

Install. equipment (vehicles) 88000 59224 Motor veh. & parts 590300 35846 2.12 I"tJ 

I 

W 

.....:J 

.....:J 

~ 
VI 

III 

N 

Table A-lO. Coet and Embodied Energy of the EPRI Single-Axis Tracking Photovoltaic -

If Syetem at the Southweet Site (Continued) I I 

"-~ 

EPRI One-Axis Tracking Cost Energy Embodied 

System Components Estimate Cost Intensity Energy. 

(Southwest site) ($1982) ($1977) SIC Sector SIC Code (Btu/ $1977) (10 9 Btu) 

DC field wiring 

Interpanel jumpers 40320 27135 Fab. wire product 420500 71355 1. 94 

Labor 479052 322402 NCST non. bldg. 110704 43107 13.90 

Neutral Cable I 147692 99397 Fab. wire product 420500 71355 7.09 

Terminate 840 565 Fab. wire product 420500 71355 0.04 

Labor 153387 103229 NCST non. bldg. 110704 43107 4.45 

Neutral Cable II 37607 25310 Fab. wire product 420500 71355 1. 81 

Terminate 4200 2827 Fab. wire product 420500 71355 0.20 

Labor 128648 86580 NCST non. bldg. 110704 43107 3.73 

Grouping cable 52500 35333 Fab. wire product 420500 71355 2.52 

Terminate 62765 42241 Fab. wire product 420500 71355 3.01 

Trench and backfill 39404 26519 NCST non. bldg. 110704 43107 1.14 

DC Bus Disc. Cab. 567561 381969 Fab. wire product 420500 71355 27.26 

Terminate 47796 32167 Fab. wire product 420500 71355 2.30 ,t:. Trench and backfill 123054 82815 NCST non. bldg. 110704 43107 3.57 0 

DC System Switchgear 

Bus discon. cabinet 1705480 1147788 Switchgear 530300 25726 29.53 

Subfield cabinet 186400 125447 Switchgear 530300 25726 3.23 

Subfield switchgear 2238000 1506174 Switchgear 530300 25726 38.75 

AC Power System 

Power cable 776250 522416 Fab. wire product 420500 71355 37.28 

Trench and backfill 12002 8077 NCST non. bldg. 110704 43107 0.35 

Tap vaults, etc. 40000 26920 Power trans. equip. 490500 31596 0.85 

AC power cable 4500 3029 Fab. wire product 420500 71355 0.22 

Terminate 6000 4038 Fab. wire product 420500 71355 0.29 

Electronic rec10ser 138500 93211 Electronic compo 570300 31502 2.94 

AC Substation 

34.5 kV OCB 190000 127870 Electronic compo 570300 31502 4.03 

Switches 80000 53840 Switchgear 530300 25726 1.39 

Buswork 85000 57205 Wiring devices 550300 40586 2.32 

Relaying, metering, etc. 110000 74030 Electronic compo 570300 31502 2.33 

Transformer 675000 454275 Transformers 530200 42591 19.35 

Grounding 10000 6730 Fab. wire product 420500 71355 0.48 f-3 

I-d 

I 

W 

-..l 

-..l 

N 
~ 

I-' 

Table A-lO. Cost and Embodied Energy of the EPRI Single-Axis Tracking Photovoltaic 

System at the Southwest Site (Concluded) 

EPRI One-Axis Tracking 

System Components 

(Southwest site) 

DC System Station/Tracking 

Transformers 

Power 

34.5 kV aux. and tracking cable 

Terminate 

480 V aux. and tracking cable 

Cost 

Estimate 

($1982) 

65000 

4500 

6000 

60000 

480 V aux. power and array power 

cable 9360 

Terminate 9600 

Tracking power panel boards 39720 

Array tracking power cable 380271 

Terminate 20160 

Labor 1309080 

Master Control 140000 

Buildings/enclosures 1220000 

Spare Parts/Equipment 377000 

O&M Equipment 

Vehicles 240000 

Tools and equipment 50000 

Cost 

($1977) 

43745 

3029 

4038 

40380 

6299 

6461 

26732 

255922 

13568 

881011 

942200 

821060 

253721 

161520 

33650 

SIC Sector 

Transformers 

Fab. wire product 

Fab. wire product 

Fab. wire product 

Fab. wire product 

Fab. wire product 

Power trans. equip. 

Fab. wire product 

Fab. wire product 

NCST non. bldg. 

Ind. controls 

NCST indust. bldg. 

Misc. metal work 

Motor veh. & parts 

Handtools 

Energy 

Intensity 

SIC Code (Btu/$1977) 

530200 42591 

420500 71355 

420500 71355 

420500 71355 

420500 71355 

420500 71355 

490500 31596 

420500 71355 

420500 71355 

110704 43107 

530500 23412 

110201 32103 

400900 65247 

590300 35846 

420200 34863 

Total: 

Embodied 

Energy 

(10 9 Btu) 

1.86 

0.22 

0.29 

2.88 

0.45 

0.46 

0.84 

18.26 

0.97 

37.98 

22.06 

26.36 

16.55 

5.79 

1.17 

1.8 x 1012 

(528 GWh) 

Btu 

'" III 

N -

-

- .. I I 

~-
Table A-ll. Cost and Embodied Energy of the EPRI Single-Axis Tracking Photovoltaic 

System at the Southeast Site 

EPRI One-Axis Tracking 

System Component$ 

(Southeast site) 

Land 

Acquisition 

Site preparation 

Power Conditioning System 

Foundation - Elec. Sys. 

Panel Compo (structural) 

Gasket tape 

Torque tube 

Torque tube pedestal conn'n. 

Linear actuator 

Cross members 

Longitudinal and center members, 

Cost 

Estimate 

($1982) 

1530000 

2690000 

7469000 

13600 

698880 

5322240 

3198720 

833280 

1747200 

keeper bars, fasteners 3386880 

Panel Comp. (Elect.) 

Nylon 12 chutes 

Busbar 

Bypass diode/heat sink 

Cover plate 

Panel Assembly 

Labor 

Equipment 

Vehicles 

Pedestal (steel) 

Pedestal Installation 

Surveying (labor) 

Auger holes (labor) 

Place concrete (labor) 

Place and align. pedestal 

Pedestal tests 

96768 

1567104 

2150400 

274176 

7136490 

421600 

28000 

1742160 

185000 

1229760 

880320 

1018164 

30000 

Cost 

($1977) 

1029690 

1810370 

5026637 

9153 

470346 

3581868 

2152739 

560797 

1175866 

2279370 

65125 

1054661 

1447219 

184520 

4802858 

283737 

18844 

1172474 

124505 

827628 

592455 

685224 

20190 

SIC Sector 

NCST elec. util. 

Power trans. equip. 

Ready-mix concrete 

Misc. plastics 

Fab. struc. steel 

Steel prod. 

General indo mach. 

Fab. struc. steel 

Fab. struc. steel 

Misc. plastics 

Wiring devices 

Electronic compo 

Steel prod. 

NCST non. bldg. 

General indo mach. 

Motor veh. & parts 

Fab. struc. steel 

NCST non. bldg. 

NCST non. bldg. 

NCST non. bldg. 

NCST non. bldg. 

NCST non. bldg. 

SIC Code 

110303 

490500 

361200 

320400 

400400 

370100 

490700 

400400 

400400 

320400 

550300 

570300 

370100 

110704 

490700 

590300 

400400 

110704 

110704 

110704 

110704 

110704 

Energy 

Intensity 

(Btu/$1977) 

30648 

31569 

80909 

63281 

49469 

115724 

28793 

49469 

49469 

63281 

40586 

31502 

115724 

43107 

28793 

35846 

49469 

43107 

43107 

43107 

43107 

43107 

Embodied 

Energy 

(10 9 Btu) 

55.48 

158.69 

0.74 

29.76 

177.19 

249.12 

16.15 

58.17 

112.76 

4.12 

42.80 

45.59 

21.35 

207.04 

8.17 

0.68 

58.00 

5.37 

35.68 

25.54 

29.54 

0.87 

'" III 

--U 

--~ 

I I 

<-~ 
III 

III 

N 

-

II I I 

~-~ 

Table A-11. Cost and Embodied Energy of the EPRI Single-Axis Tracking Photovoltaic 

System at the Southeast Site (Continued) 

EPRI One-Axis Tracking Cost Energy Embodied 

System Components Estimate Cost Intensity Energy 

(Southeast site) ($1982) ($1977) SIC Sector SIC Code (Btu/$1977) (l09 Btu) 

Panel Installation (labor) 964100 648839 NCST non. bldg. 110704 43107 27.97 

Install. equipment (vehicles) 88000 59224 Motor veh. & parts 590300 35846 2.12 

DC Field Wiring 

Interpanel jumpers 40320 27135 Fab. wire product 420500 71355 1. 94 

Labor 479052 322402 NCST non. bldg. 110704 43107 13.90 

Neutral Cable I 147692 99397 Fab. wire product 420500 71355 7.09 

Terminate 840 565 Fab. wire product 420500 71355 0.04 

Labor 153387 103229 NCST non. bldg. 110704 43107 4.45 

.t> Neutral Cable II 37607 25310 Fab. wire product 420500 71355 1. 81 

w Terminate 4200 2827 Fab. wire product 420500 71355 0.20 

Labor 128648 86580 NeST non. bldg. 110704 43107 3.73 

Grouping cable 52500 35333 Fab. wire product 420500 71355 2.52 

Terminate 62765 42241 Fab. wire product 420500 71355 3.01 

Trench and backfill 39404 26519 NCST non. bldg. 110704 43107 1.14 

DC Bus Disc. Cab. 567561 381969 Fab. wire product 420500 71355 27.26 

Terminate 47796 32167 Fab. wire product 420500 71355 2.30 

Trench and backfill 123054 82815 NCST non. bldg. 110704 43107 3.57 

DC system switchgear 

Bus discon. cabinet 1705480 1147788 Switchgear 530300 25726 29.53 

Subfield cabinet 186400 125447 Switchgear 530300 25726 3.23 

Subfield switchgear 2238000 1506174 Switchgear 530300 25726 38.75 

AC Power System 

Power cable 776250 522416 Fab. wire product 420500 71355 37.28 

Trench and backfill 12002 8077 NCST non. bldg. 119704 43107 0.35 

Tap vaults, etc. 40000 26920 Power trans. equip. 490500 31596 0.85 

AC power cable 4500 3029 Fab. wire product 420500 71355 0.22 

Terminate 6000 4038 Fab. wire product 420500 71355 0.29 1-,3 

Electronic recloser 138500 93211 Electronic compo 570300 31502 2.94 tU 

I 

W 

-.J 

-.J 

N 
..,. 

..,. 

Tabl.e A-ll. Cost and Embodied Energy of the EPRI Singl.e-Axis 

System at the Southeast Site (Concluded) 

EPRI One-Axis Tracking 

System Components 

(Southeast site) 

AC Substation' 

34.5 kV OCB 

Switches 

Buswork 

Relaying, metering, etc. 

Transformer 

Grounding 

DC System Station/Tracking 

Transformers 

Power 

34.5 kV aux. and tracking cable 

Terminate 

480 V aux. and tracking cable 

Cost 

Estimate 

($1982) 

190000 

80000 

85000 

110000 

675000 

10000 

65000 

4500 

6000 

60000 

480 V aux . power and array power 

cable 9360 

Terminate 9600 

Cost 

($1977) 

127870 

53840 

57205 

74030 

454275 

6730 

43745 

3029 

4038 

40380 

6299 

6461 

SIC Sector 

Electronic compo 

Switchgear 

Wiring devices 

Electronic compo 

Transformers 

Fab. wire product 

Transformers 

Fab. wire product 

Fab. wire product 

Fab. wire product 

Fab. wire product 

Fab. wire product 

Tracking Photovol.taic 

Energy 

Intensity 

SIC Code (Btu/$1977) 

570300 31502 

530300 25726 

550300 40586 

570300 31502 

530200 42591 

420500 71355 

530200 42591 

420500 71355 

420500 71355 

420500 71355 

420500 71355 

420500 71355 

Tracking power panel boards 39720 26732 Power trans. equip. 490500 31596 

420500 71355 

420500 71355 Array tracking power cable 380271 255922 Fab. wire product 

Terminate 20160 13568 Fab. wire product 

Labor 1309080 881011 NCST non. bldg. 110704 43107 

Master Control 1400000 942200 Ind. controls 530500 23412 

Buildings/Enclosures 1220000 821060 NCST indust. bldg. 110201 32103 

Spare Parts/Equipment 374000 251702 Misc. metal work 400900 65247 

O&M Equipment 

Vehicles 240000 161520 Motor veh. & parts 590300 35846 

Tools and equipment 50000 33650 Handtools 420200 34863 

Total: 

U'I 

III 

N -

-. I I 

"-. Embodied 

Energy 

(10 9 Btu) 

4.03 

1. 39 

2.32 

2.33 

19.35 

0.48 

1. 86 

0.22 

0.29 

2.88 

0.45 

0.46 

0.84 

18.26 

0.97 

37.98 

22.06 

26.36 

16.42 

5.79 

1.17 

1. 725 x 1012 Btu 

(504 GWh) 

8 

'"d 

I 

W 

-..J 

-..J 

N 
Document Control 11. SERI Report No. 

Page SERI/TP-260-3772 

4. Title and Subtitle 

1

2. NTIS Accession No. 

DE90000337 

C02 Emissions from Coal-Fired and Solar Electric 

Power Plants 

7. Author(s) 

F. Kreith, P. Norton, and D. Brown 

9. Performing Organization Name and Address 

Solar Energy Research Institute 

1617 Cole Boulevard 

Golden, Colorado 80401-3393 

12. Sponsoring Organization Name and Address 

15. Supplementary Notes 

16. Abstract (Limit: 200 words) 

3. Recipient's Accession No. 

5. Publication Date 

May 1990 

6. 

8. Performing Organization Rept. No. 

10. ProjecVTaskiWork Unit No. 

2000.4010 11. Contract (C) or Grant (G) No. 

(C) 

(G) 

13. Type of Report & Period Covered 

';['echnica1 Report 

14. 

This report presents esti~ates of the lifetime carbon dioxide emissions from 

coal-fired, photovo1taic, and solar thermal electric power plants in the 

United States. These C02 estimates are based on a net energy analysis derived 

from both operational systems and detailed design studies. It appears that 

energy conservation measures and shifting from fossil to renewable energy 

sources have significant long-term potential to reduce carbon dioxide production 

caused by energy generation and thus mitigate global warming. The implications 

of these results for a national energy policy are discussed. 

17. Document Analysis 

a. Descriptors Solar power plants ; solar thermal power plants ; photovo1taic 

power plants ; fossil-fuel power plants ; air quality ; 

air pollution abatement 

b. Identifiers/Open-Ended Terms 

c. UC Categories 

233 

18. Availability Statement 

National Technical Information Service 

U.S. Department of Co~erce 

5285 Port Royal Road 

Springfield, Virginia 22161 

Form No. 0069 (3-25-82) 

19. No. of Pages 

53 

20. Price 

A04