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CO2 Emissions from Coal-Fired and Solar Electric Power Plants

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CO2 Emissions from Coal-Fired and Solar Electric Power Plants 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 agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, com­ pleteness, 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 con­ stitute 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. Printed in the United States of America Available from: National Technical Information Service U.S. Department of Commerce 5285 Port Royal Road Springfield, VA 22161 Price: Microfiche A01 Printed Copy A04 Codes are used for pricing ali publications. The code is determined by the number of pages in the publication. Information pertaining to the pricing codes can be found in the current issue of the following publications which are generally available in most libraries: Energy Research Abstracts (ERA); Govern­ ment Reports Announcements and Index (GRA and I); Scientific and Technical Abstract Reports (STAR); and publication NTIS-PR-360 available from NTIS 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 TP-3772 TABLE OF CONTENTS 1.0 Introduction 1 2.0 Options for Reducing CO2 Generation 3 2.1 A Method of Estimating CO2 Emissions 4 2.2 Solar Thermal Power Plants . 5 2.3 Photovoltaic Power Plants .. 11 2.4 A Comparison of Solar and Coal-Fired Electric Power Plants . 13 2.5 The Potential of Cogeneration for Reducing CO 2 Production 21 3.0 Discussion 24 4.0 Implications for a National Energy Policy 28 5.0 References 29 Appendix: Component costs for Molten-Salt Central Receiver and Photovoltaic Systems . 32 iv TP-3772 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 flat- plate photovoltaic power plant . 15 2-6 EPRI's one-axis, tracking, flat-plate system structural support concept . 16 2-7 Total CO2 production per GWh e of output energy 20 2-8 Schematic diagrams of combined heat and electricity cogeneration systems ............... 21 v TP-3772 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 . 5 2-2 Prime Contractors Supplying Cost Data for the 100-MWe Solar Thermal Power Plant . 5 2-3 Solar Thermal Power Plant System Design and Performance Specifications 8 2-4 Cost, Embodied Energy, and CO2 Production of the Key Components of the 100-MWe Solar Thermal Power Plant 9 2-5 Energy Investment in the Energy Conversion Subsystem of the Solar Thermal Power Plant .... 10 2-6 Cost, Embodied Energy, and CO 2 Production of the Key Components of the City of Austin's 300-kWe Photovoltaic Plant . 14 2-7 Key Design Characteristics for the EPRI Flat-Plate, One-Axis, Tracking Photovoltaic Central Station Design ....... ..... 15 2-8 Cost, Embodied Energy, and CO 2 Production of the Key Components of the EPRI Single-Axis, Tracking Photovoltaic System at the Southwest Site 17 2-9 Cost, Embodied Energy, and CO2 Production of the Key Components of the EPRI Single-Axis, Tracking Photovoltaic System at the Southeast Site 18 2-10 Net Lifetime Energy Output and CO 2 Production per GWhe for Electric Power Plants with a 30-year Lifetime 19 2-11 Potential for Reducing CO2 by Using Cogeneration Systems 23 3-1 Comparison of CO 2 Production per GWhe Net Lifetime Energy Output for Various Electric Power Technologies 26 A-1 Receiver Component Costs and Material Weights for the Solar Thermal System . 33 A-2 Tower Component Costs for the Solar Thermal System 33 A-3 Heliostat Material Costs for the Solar Thermal System 34 vi TP-3772 LIST OF TABLES (CONCLUDED) Table A-4 Transport System Material Costs for the Solar Thermal System ...... 35 A-5 Storage System Component Costs for the Solar Thermal System 35 A-6 Energy Conversion System Component Costs for the Solar Thermal System 36 A-7 Balance-of-Plant Costs for the Solar Thermal System 37 A-8 Operation and Maintenance Costs for the Solar Thermal System ...... 37 A-9 Cost and Embodied Energy of the City of Austin's 300-kW Photovoltaic Plant ......... 38 A-10 Cost and Embodied Energy of the EPRI Single-Axis Tracking Photovoltaic System at the Southwest Site 39-41 A-11 Cost and Embodied Energy of the EPRI Single-Axis Tracking Photovoltaic System at the Southeast Site 42-44 vii 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 CO 2 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 CO 2 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 CO 2 concentration increases. These data indicate that the burning of fossil fuels, coupled with the destruction of vast forests, have led to a rise in CO 2 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 CO 2 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 CO 2 (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 CO 2 concentration in the atmosphere (Bath and Feucht 1990). However, if we continue burning fossil fuels at current rates, the buildup of CO 2 in the atmosphere will trap increasing amounts of infrared radiation emitted by the Earth and result in a warming of the Earth's surface. 1 TP-3772 0 0.6 <Xl (a) 0 <D 0.4 0 I:: I:: Cl .2 co .0: - 0) 0.2 .~ E '" 0)0 "000 0 Ii>~ ... , -0.2 cult>:Jo "'0) 0),... -0.4 a. E E 0 0) ... -0.6 1-- -0.8 1850 1870 1890 1910 1930 1950 1970 1990 350 (b) 340 I::o c:- 330 ~... ~. I:: ·E 320 -0) ... (.) 0) I:: a. o en 310 (.) t:: NCO 300 ou- a. 290 280 1850 1870 1890 1910 1930 1950 1970 1990 (i) I:: 6x109 g (c) I:: 5x109 0 U :J 4x109 "0e a. 9 I:: 10 0 .0 ...co 2x109 () /1" ........ ~ :J 1x109 I:: -- .... --" I:: --- <: 0 1850 1870 1890 1910 1930 1950 1970 1990 Figure 1-1.
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