RENEWABLE ENERGY. A First Course. Robert Ehrlich. Lap) CRC Press \V J Taylor & Francis Group Boca Raton London New York

Transcription

1 RENEWABLE ENERGY A First Course Robert Ehrlich Lap) CRC Press \V J Taylor & Francis Group Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an inform.» business

2 Preface Acknowledgments Author 1 Introduction Why Another Book on Energy? Why Is Energy So Important to Society? Exactly What Is Energy? Might There Be Some New Forms of Energy Not Yet Known? What Are the Units of Energy? Laws of Thermodynamics Example 1: Calculating Energy When Power Varies in Time What Is an Energy Source? What Exactly Is the World's Energy Problem? Climate Change Is Human Population Growth the Root Cause of Our Energy and Environmental Problem? How Much Time Do We Have? 12 How Is Green or Renewable Energy Defined? 1.10 Why Has Renewable Energy and Conservation Been Neglected Until Fairly Recently? 1.11 Does Energy Efficiency Really Matter? Example 2: Which Solar Panels Are Superior': ' Which Renewable Energy Sources Hold the Greatest Promise? 17 XV xvii xix Who Are the World Leaders in Renewable Energy? 1.14 What Is Our Likely Energy Future? What Is Projected for Future Employment in the Renewable Energy Field? 1.15 Complexities in Charting the Best Course for the Future Example 3: How the Usage of Wind Power to Offset Coal-Fired Plants Can Generate More Emissions Not Less 1.16 Summary Fossil Fuels 2.1 Introduction Carbon Cycle 2.2 Coal Composition of Coal Example 1: Energy Content of Coal Formation of Coal Resource Base Electricity Generation from Coal Example 2: Efficiency of a Coal-Fired Power Plant Rankine Cycle Conversion of Coal to a Transportation Fuel Coal Mining VII

3 2.2.8 Environmental Impacts of Coal Atmospheric Emissions from Coal Power Plants Other Atmospheric Emissions Including Radioactivity Waterborne Pollution and Acid Rain Example 3: Connection between Acidity and ph Levels Impacts on the Land Carbon Sequestration and "Clean" Coal Petroleum and Natural Gas History of Petroleum Use Resource Base of Oil and Gas Formation and Location of Oil and Gas Are Coal, Oil, and Gas Really Fossil Fuels? Peak Oil Example 4: How Many Years Are Left? Petroleum and Natural Gas Processing Extraction of Oil and Gas Refining of Gas and Oil Gas and Oil Power Plants Example 5: A Binary Cycle Plant Environmental Impacts of Oil and Gas Summary Nuclear Power Introduction Early Years Discovery of the Atomic Nucleus Mathematical Details of the Rutherford Scattering Experiment Example 1: Setting an Upper Limit to the Nuclear Size Composition and Structure of the Atom and Its Nucleus Nuclear Radii Nuclear Forces Ionizing Radiation and Nuclear Transformations Nuclear Mass and Energy Nuclear Binding Energy Energy Released in Nuclear Fusion Example 2: Estimating the Energy Released in Fusion Mechanics of Nuclear Fission Example 3: Estimating the Energy Released in Fission Mechanics of Nuclear Fusion Example 4: Find the Temperature Needed to Initiate d-d Fusion Radioactive Decay Law Health Physics Radiation Detectors Radiation Sources Example 5: Comparison of Two Radioactive Sources Impacts of Radiation on Humans Safe Radiation Level and Cancer Risks Relative Risk Summary Nuclear Power 4.1 Introduction 4.2 Early History

4 ix 4.3 Critical Mass Neutron Absorption by Uranium Nuclei Why Does Density Matter in Determining Critical Mass? Example 1: Estimation of Critical Mass Nuclear Weapons and Nuclear Proliferation World's First Nuclear Reactor Nuclear Reactors of Generations I and II Existing Reactor Types Choice of Moderator Example 2: How Much Energy Does a Neutron Lose on Average during Elastic Collisions? Choice of Fuel Choice of Coolant Reactor Accidents Fukushima Chernobyl Causes of Chernobyl Reactor Accidents: Three Mile Island Front End of the Fuel Cycle-. Obtaining the Raw Material Back End of the Fuel Cycle: Nuclear Waste Shipping Nuclear Waste Economics of Large-Scale Nuclear Power Small Modular Reactors Nuclear Fusion Reactors Summary Biofuels Introduction Photosynthesis Example 1: Efficiency of Photosynthesis Example 2: Best Wavelengths of Light for Photosynthesis Biofuel Classifications Choice of Feedstock for Biofuels Biofuel Production Processes Example 3: Loss of Energy When Combustible Material Is Moist Generation of Biofuels Other Uses of Biofuels and Social-Environmental Impacts Biofuels from Wastes and Residues Agricultural Wastes Central Role of Agriculture in a Sustainable Future Vertical Farming Artificial Photosynthesis Summary Geothermal Energy Introduction and Why Geothermal Is Important History and Growth of Usage Geographic Distribution Sources of the Earth's Thermal Energy Comparison with Other Energy Sources Geophysics of the Earth's Interior Thermal Gradient Characterization and Relative Abundance of the Resource Impact of the Thermal Gradient Example L Relative Energy Content for Two Gradients Questioning Our Assumptions 162

5 6.4.4 Other Geologic Factors Affecting the Amount of the Resource Hot Dry Rock Formations Geothermal Electricity Power Plants Example 2: Efficiency of a Geothermal Power Plant Residential and Commercial Geothermal Heating Economics of Residential Geothermal Sustainability of Geothermal Depletion of a Geothermal Field Example 3: Lengthening the Lifetime Example 4: A 100 MW Power Plant Environmental Impacts Released Gases Impact on Land and Freshwater Do Heat Pumps Cut Down on CO2 Emissions? HA 6.9 Economics of Geothermal Electricity UA Drilling Costs HA Beating the Exponential? Why the Exponential Dependence of Cost on Well Depth? Is Spallation Drilling the Answer? Why Spallation Drilling Cost Might Be a Linear Function of Depth Summary Wind Power Introduction and Historical Uses Wind Characteristics and Resources v-cubed Dependence of Power on Wind Speed Wind Speed Distributions Wind Speed as a Function of Height Example 1: Turbine Power versus Height Power Transfer to a Turbine Turbine Types and Terms Lift and Drag Forces and the Tip-Speed Ratio Example 2: The Cup Anemometer Horizontal versus Vertical Axis Turbines Number of Turbine Blades, and Solidity Variable and Fixed Rotation Rate Turbines Controlling and Optimizing Wind Turbine Performance Example 3: Turbine Power and Typical Blade Diameter Maximizing Power below the Rated Wind Speed Limiting Power above the Rated Wind Speed Electrical Aspects and Grid Integration Asynchronous Generator Small Wind Example 4: Comparing Two Turbines Offshore Wind Environmental Impacts Unusual Designs and Applications Airborne Turbines Wind-Powered Vehicles Directly Downwind Faster-than-the-Wind

6 xi Hydropower 8.1 Introduction to Hydropower A dvan tages of Hydropo wer Basic Energy Conversion and Conservation Principles Impulse Turbines Design Criteria for Optimum Performance Example h Designing a Pelton Turbine Reaction Turbines Turbine Speed and Turbine Selection Specific Speed Pumped Storage Hydroelecthcity Small Hydro 8.2 Wave, Tidal, and Ocean Thermal Power Resources Wave Motion and Wave Energy and Power Example 2: Power of a Wave Devices to Capture Wave Power 8.3 Introduction to Tidal Power and the Cause of the Tides Tidal Current Power Impoundment (Barrage) Tidal Power Dynamic Tidal Power 8.4 Ocean Thermal Energy Conversion 8.5 Social and Environmental Impacts of Hydropower 8.6 Summary Reference Solar Radiation and Earth's Climate 9.1 Introduction 9.2 Electromagnetic Radiation 9.3 Types of Spectra Blackbody Spectrum 9.4 Apparent Motion of the Sun in the Sky Example 1: Finding the Solar Declination O/l С Z4b Availability of Solar Radiation on Earth Example 2: Finding the Number of Daylight Hours 258 Optimum Collector Orientation and Tilt 260 Greenhouse Effect Expected Average Surface Summary Temperature of the Planet 261 Natural Greenhouse Effect 262 Climate Change Feedbacks Positive Feedbacks Negative Feedbacks 265 Four Greenhouse Gases 266 Global Temperature Variation and Its Causes 268 Climate Projections for the Coming Century 270 "Tipping Points" in the Climate System 271 Categories of Positions in the Global Warming Debate 272 Arguments of Global Warming Skeptics and Deniers Solar Thermal Introduction Solar Water-Heating Systems Flat-Plate Collectors Evacuated Collectors Collector and System Efficiency Example 1: A Flat-Plate versus an Evacuated Tube Collector Thermal Losses in Pipes Example 2: Thermal Loss in a Pipe Water Tanks and Thermal Capacitance 291

7 Example 3: Insulating a Hot Water Tank to Reduce Thermal Losses Passive Solar Hot Water System Example 4: Finding the Fluid Flow Rate in a Thermosiphon Hot Water Heater Swimming Pool Heating Space Heating and Cooling Three Applications Well Suited to Developing Nations Crop Drying Water Purification Solar Cooking Electricity Generation Concentration Ratio and Temperature Parabolic Dish Systems and "Power Towers" Solar Chimneys Summary 308 Appendix: Four Heat Transfer Mechanisms A. 1 Conduction A.2 Convection A.3 Radiation A.4 Example 5: Validity of the First-Order Approximation A.5 Mass Transport Photovoltaics Introduction Conductors, Insulators, and 12 Semiconductors Example 1: Using the Fermi Distribution Increasing the Conductivity of Semiconductors through Doping Example 2: Effect of Doping on Conductivity' pn Junction Generic Photovoltaic Cell Electrical Properties of a Solar Cell Efficiency of Solar Cells and Solar Systems Fill Factor Temperature Dependence of Efficiency Example 3: Impact of Temperature on Efficiency and Power Output Spectral Efficiency and Choice of Materials Efficiency of Multijunction Cells Efficiency of Solar Systems Grid Connection and Inverters Other Types of Solar Cells Thin Films Dye-Sensitized Cells Environmental Issues Summary 336 Appendix-. Basic Quantum Mechanics and the Formation of Energy Bands A.1 Finding Energy Levels 11.A.2 and Wavefunctions 337 Coupled Systems and Formation of Energy Bands Energy Conservation and Efficiency Introduction Example 1-.What Went Wrong? Factors Besides Efficiency Influencing Energy-Related Choices Biking to Work More Efficient Solar Collectors 349

8 xiii 12.3 Lowest of the Low Hanging Fruit Residential Sector Lighting Example 2-. Lighting Cost Comparison Energy Management Cogeneration Thermoelectric Effect: Another Way to Use Cogeneration Conservation and Efficiency in Transportation Thermoelectric Energy Recovery Example 3: What Efficiency of a Thermoelectric Generator Is Needed? Regenerative Brakes and Shock Absorbers Improving Engine Efficiency Lighter and Smaller Vehicles Alternate Fuels Alternatives to the Internal Combustion Engine Using Automobiles and Trucks Less or Using Them More Efficiently Obstacles to Efficiency and Conservation 12.5 Is Energy Efficiency and Conservation Ultimately Futile? Jevon 's Paradox 12.6 Summary Energy Storage and Transmission Energy Storage Introduction Mechanical and Thermal Energy Storage Pumped Hydro Thermal Storage Compressed Air Energy Storage Flywheel Energy Storage Electric and Magnetic Energy Storage Batteries Ultracapacitors Fuel Cells Hydrogen Storage and Cars Powered by It Battery-Powered Electric Cars Magnetic Storage Nuclear Batteries Antimatter Summary Energy Transmission Introduction Electricity Transmission Alternating Current Transmission and Distribution Alternating versus Direct Current High Voltage Transmission Lines Skin Effect Direct Current Power Transmission Example 6: Power Losses with HVAC and HVDCTransmission Lines 406

9 xiv Contents with the Grid Goals for a Smart Grid Summary 14 Climate and Energy: Policy, Politics, and Public Opinion 14.1 How Important Are International Agreements? 14.2 What Are the Top-Three GHG Emitters Doing? China India Appendix Index United States 14.3 How Much Time Does the World Have to Move Away from Fossil Fuels? 14.4 How Has Public Opinion Evolved? Climate Change Renewable Energy Nuclear Power 14.5 Best Way Forward 14.6 Summary 14.7 Some Concluding Thoughts