Nanophysics of Solar and Renewable Energy E-Book

Edward L. Wolf

• Herausgeber: Wiley-VCH
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 520

Veröffentlichungsjahr: 2012

Beschreibung

This easy accessible textbook provides an overview of solar to electric energy conversion, followed by a detailed look at one aspect, namely photovoltaics, including the underlying principles and fabrication methods. Ed Wolf, an experienced author and teacher, reviews such green technologies as solar-heated-steam power, hydrogen, and thermoelectric generation, as well as nuclear fusion. Throughout the book, carefully chosen, up-to-date examples are used to illustrate important concepts and research tools.
The opening chapters give a broad and exhaustive survey of long term energy resources, reviewing current and potential types of solar driven energy sources. The core part of the text on solar energy conversion discusses different concepts for generating electric power, followed by a profound presentation of the underlying semiconductor physics and rounded off by a look at efficiency and third-generation concepts. The concluding section offers a rough analysis of the economics relevant to the large-scale adoption of photovoltaic conversion with a discussion of such issues as durability, manufacturability and cost, as well as the importance of storage.
The book is self-contained so as to be suitable for students with introductory calculus-based courses in physics, chemistry, or engineering. It introduces concepts in quantum mechanics, atomic and molecular physics, plus the solid state and semiconductor junction physics needed to attain a quantitative understanding of the current status of this field. With its comments on economic aspects, it is also a useful tool for those readers interested in a career in alternative energy.

Leseprobe

Contents

Cover

Related Titles

Title Page

Copyright

Dedication

Preface

Chapter 1: A Survey of Long-Term Energy Resources

1.1 Introduction

Chapter 2: Physics of Nuclear Fusion: the Source of all Solar-Related Energy

2.1 Introduction: Protons in the Sun's Core

2.2 Schrodinger's Equation for the Motion of Particles

2.3 Protons and Neutrons and Their Binding

2.4 Gamow's Tunneling Model Applied to Fusion in the Sun's Core

2.5 A Survey of Nuclear Properties

Chapter 3: Atoms, Molecules, and Semiconductor Devices

3.1 Bohr's Model of the Hydrogen Atom

3.2 Charge Motion in Periodic Potential

3.3 Energy Bands and Gaps

3.4 Atoms, Molecules, and the Covalent Bond

3.5 Tetrahedral Bonding in Silicon and Related Semiconductors

3.6 Donor and Acceptor Impurities; Charge Concentrations

3.7 The PN Junction, Diode I–V Characteristic, Photovoltaic Cell

3.8 Metals and Plasmas

Chapter 4: Terrestrial Approaches to Fusion Energy

4.1 Deuterium Fusion Demonstration Based on Field Ionization

4.2 Deuterium Fusion Demonstration Based on Muonic Hydrogen

4.3 Deuterium Fusion Demonstration in Larger Scale Plasma Reactors

Chapter 5: Introduction to Solar Energy Conversion

5.1 Sun as an Energy Source, Spectrum on Earth

5.2 Heat Engines and Thermodynamics, Carnot Efficiency

5.3 Solar Thermal Electric Power

5.4 Generations of Photovoltaic Solar Cells

5.5 Utilizing Solar Power with Photovoltaics: the Rooftops of New York versus Space Satellites

5.6 The Possibility of Space-Based Solar Power

Chapter 6: Solar Cells Based on Single PN Junctions

6.1 Single-Junction Cells

6.2 Thin-Film Solar Cells versus Crystalline Cells

6.3 CIGS (CuIn1−xGaxSe2) Thin-Film Solar Cells

6.4 CdTe Thin-Film Cells

6.5 Dye-Sensitized Solar Cells

6.6 Polymer Organic Solar Cells

Chapter 7: Multijunction and Energy Concentrating Solar Cells

7.1 Tandem Cells, Premium and Low Cost

7.2 Organic Molecules as Solar Concentrators

7.3 Spectral Splitting Cells

7.4 Summary and Comments on Efficiency

7.5 A Niche Application of Concentrating Cells on Pontoons

Chapter 8: Third-Generation Concepts, Survey of Efficiency

8.1 Intermediate Band Cells

8.2 Impact Ionization and Carrier Multiplication

8.3 Ferromagnetic Materials for Solar Conversion

8.4 Efficiencies: Three Generations of Cells

Chapter 9: Cells for Hydrogen Generation; Aspects of Hydrogen Storage

9.1 Intermittency of Renewable Energy

9.2 Electrolysis of Water

9.3 Efficient Photocatalytic Dissociation of Water into Hydrogen and Oxygen

9.4 The “Artificial Leaf” of Nocera

9.5 Hydrogen Fuel Cell Status

9.6 Storage and Transport of Hydrogen as a Potential Fuel

9.7 Surface Adsorption for Storing Hydrogen in High Density

9.8 Economics of Hydrogen

Chapter 10: Large-Scale Fabrication, Learning Curves, and Economics Including Storage

10.1 Fabrication Methods Vary but Exhibit Similar Learning Curves

10.2 Learning Strategies for Module Cost

10.3 Thin-Film Cells, Nanoinks for Printing Solar Cells

10.4 Large-Scale Scenario Based on Thin-Film CdTe or CIGS Cells

10.5 Comparison of Solar Power Versus Wind Power

10.6 The Importance of Storage and Grid Management to Large-Scale Utilization

Chapter 11: Prospects for Solar and Renewable Power

11.1 Rapid Growth in Solar and Wind Power

11.2 Renewable Energy Beyond Solar and Wind

11.3 The Legacy World, Developing Countries, and the Third World

11.4 Can Energy Supply Meet Demand in the Longer Future?

Appendix A: Exercises

Exercises to Chapter 1

Exercises to Chapter 2

Exercises to Chapter 3

Exercises to Chapter 4

Exercises to Chapter 5

Exercises to Chapter 6

Exercises to Chapter 7

Exercises to Chapter 8

Exercises to Chapter 9

Exercises to Chapter 10

Exercises to Chapter 11

Glossary of Abbreviations

References

Index

Related Titles

Wengenmayr, R., Bührke, T. (eds.)Renewable EnergySustainable Energy Concepts for the Future2012ISBN: 978-3-527-41108-5

Vogel, W., Kalb, H.Large-Scale Solar Thermal PowerTechnologies, Costs and Development2010ISBN: 978-3-527-40515-2

Quaschning, V.Renewable Energy and Climate Change2010ISBN: 978-0-470-74707-0

Wolf, E. L.Quantum NanoelectronicsAn Introduction to Electronic Nanotechnologyand Quantum Computing2009ISBN: 978-3-527-40749-1

Würfel, P.Physics of Solar CellsFrom Basic Principles to Advanced Concepts2009ISBN: 978-3-527-40857-3

Freris, L., Infield, D.Renewable Energy in Power Systems2008ISBN: 978-0-470-01749-4

De Vos, A.Thermodynamics of Solar Energy Conversion2008ISBN: 978-3-527-40841-2

Wolf, E. L.Nanophysics and NanotechnologyAn Introduction to Modern Conceptsin Nanoscience2006ISBN: 978-3-527-40651-7

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© 2012 Wiley-VCH Verlag & Co. KGaA, Boschstr. 12, 69469 Weinheim, Germany

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Composition Thomson Digital, Noida, India

Cover Design Schulz Grafik-Design, Fußgönheim

Print ISBN: 978-3-527-41052-1 (HC) 978-3-527-41046-0 (SC)

ePDF ISBN: 978-3-527-64631-9

ePub ISBN: 978-3-527-64630-2

mobi ISBN: 978-3-527-64629-6

oBook ISBN: 978-3-527-64628-9

In Memory of Ned

Edward O'Brien Wolf

1973–2011

Preface

This book is a text on aspects of solar and renewable energy conversion based on quantum physics or “nanophysics.” We take a broader view of renewable energy than is common, including deuterium-based fusion energy as approached through Tokamak-type fusion reactors. We use the physics of the sun to introduce the ideas of quantum mechanics.

Our book may be regarded as a vehicle for teaching modern and solid-state physics taking examples from the contemporary energy arena. We assume that the reader understands elementary college physics and related college-level mathematics, chemistry, and computer science. Exercises are provided for each of the 11 chapters of the book.

We omit nuclear fission power on the basis that it is available engineering, as well as that the supplies of uranium are limited.

A second view of the book is as explaining and assessing opportunities for “nanophysics” -based technology toward solving the world's looming energy problem. Earth has a population of 7 billion and rising, we are at 1 billion autos, headed toward 2 billion, with rising demand in developing nations. But oil will sharply rise in price on a scale of 30 years, the timescale on which the easily accessible oil will be used. There is definitely a problem to be solved, even without involving questions of climate change.

Fusion reactors are not usually regarded as “nanotechnology” but certainly are based on the nanophysics or quantum physics of nuclear reactions. Schrodinger's equation was used by George Gamow to explain radioactive decay, which is an inverse process to fusion. The sun would not operate without quantum mechanical tunneling of protons through Coulomb barriers. The “Tokamak” class of toroidal fusion reactors (as represented by ITER, the international fusion energy project in Cadarache, France) is the culmination of decades of fusion research with a huge accumulated literature. The complexity of this literature may have discouraged text book writers from dealing with the subject, even though the basis of the toroidal reactor is easily understood.

It is an elementary exercise in plasma physics to find that plasma containment in orbits of particles around magnetic field lines and Faraday's law of magnetic induction can lead to I2R heating of a gas (plasma) of fusible ions having small heat capacity, at temperatures much higher than that in the sun, up to 150 million K. A temperature of 15 million Kelvins (core of the sun) is sufficient for proton–proton fusion, powering our whole existence, only because of the high density, on the order of 150 g/cc (150 times the density of water) of hydrogen at the sun's core. This density at 15 × 106 K is unachievable terrestrially but higher temperatures are available at lower densities on the order of 1020 particles/m3.

The physics of solar cells and photocatalytic production of hydrogen from water is introduced in stages: from atoms to covalent bonds to semiconductors to PN junctions. We emphasize durable thin-film solar cells that can be produced on roller-carried aluminum foil substrates in air by printing stoichiometric nanoparticles. We mention in passing that First Solar has a billion-dollar contract to build a 2 gigawatt solar cell facility in Inner Mongolia. On the other hand, we do not attempt to treat laser-based methods of terrestrial fusion, even though they may have promise.

A hindrance to interdisciplinary endeavors is the existence of compartmented literatures, such as the overwhelming literature of the Tokomak reactor, or the details of particle physics, which attest to the accumulation of knowledge but have some effect of putting walls around the knowledge. The successful worker must have the energy and audacity to plunge in to extract what is needed, overcoming barriers in names, in notation, and in choice of units, which sometimes obscure simple basic facts.

The author has benefited from teaching three classes of engineering and science graduate and undergraduate students in “Physics of Alternative Energy” at NYU Poly. In particular, he has benefited from class notes taken by Manasa Medikonda in Spring 2010. Students who have helped in this process include Angelantonio Tafuni, Karandeep Singh, Mingbo Xu, Paul-Henry Volmar, Nikita Supronova, and Diego Del'Antonio. Dell Jones of Regenesis Power is thanked for information on the lower right cover photo, of the 2 MW solar cell installation at Florida Gulf Coast University, and Dr. Karl-Heinz Haas of Fraunhofer Institute for Solar Energy is thanked for information on the upper right cover photo of a dye-sensitized flexible solar cell developed at Freiburg. The author thanks Prof. Lorcan Folan and Ms. DeShane Lyew in the Applied Physics Office for help in several ways. The assistance of Edmund Immergut, Consulting Editor, and of Vera Palmer and Ulrike Werner at Wiley-VCH, is gratefully acknowledged. Manasa Medikonda, Mahbubur Rahman, and Ankita Shah have been very helpful in preparing the manuscript. Carol Wolf, Ph.D. in mathematics and Prof. of Computer Science, has been a constant source of support in this project.

Brooklyn NY

July 2012

Edward L. Wolf

Chapter 1

A Survey of Long-Term Energy Resources

1.1 Introduction

All energy resources on earth have come from the sun, including the fossil fuel deposits that power our civilization at present. Plants grew by photosynthesis starting in the carboniferous era, about 300 million years ago, and the decay of some of these, instead of oxidizing back into the atmosphere, occurred underground in oxygen-free zones. These anaerobic decays did not release the carbon, but reduced some of the oxygen, leading to the present deposits of oil, gas, and coal. These deposits are now being depleted on a 100-year timescale, and will not be replaced. Once these accumulated deposits are depleted, no quick replenishment is possible. The energy usage will have to reduce to what will be available in the absence of the huge deposits. The words sustainable and renewable apply to this vision of the future.

There is clear evidence that the amount of available oil is limited, and is distributed only to depths of a few miles. The geology of oil very clearly indicates limited supplies. It is agreed that the continental U.S. oil supplies have mostly been depleted. Deffeyes (Deffeyes, K. (2001) “Hubbert's Peak” (Princeton Univ. Press, Princeton) authoritatively and clearly” explains that liquid oil was formed over geologic time in favored locations and only in a “window” of depths between 7500 and 15 000 feet, roughly 1.5–3 miles. (At depths more than 3 miles the temperature is too high to form liquid oil from biological residues, and natural gas forms). The limited depth and the extremely long time needed to form oil from decaying organic matter (it only occurs in particular anaerobic, oxygen-free locations, otherwise the carbon is released as gaseous carbon dioxide), support the nearly obvious conclusion that the world's accessible oil is going to run out, certainly on a timescale of 100 years.

Furthermore, scientists increasingly agree that accelerated oxidation of the coal and oil that remain, as implied by the present energy use trajectory of advanced and emerging economies, is fouling the atmosphere. Increased combustion contributes to changes in the composition of the rather slim atmosphere of the earth in a way that will alter the energy balance and raise the temperature on the earth's surface. Dramatic loss of glaciers is widely noted, in Switzerland, in the Andes Mountains, and in the polar icecaps, which relates to sea-level rises.

New sources of energy to replace depleting oil and gas are needed. The new energy sources will stimulate changes in related technology. An increasing premium will probably be placed on new sources and methods of use that limit emission of gases that tend to trap heat in the earth's atmosphere. New emphasis is surely to be placed on efficiency in areas of energy generation and use. Conservation and efficiency are admired goals that are being reaffirmed.

All energy comes from the sun, from the direct radiation, from the indirectly resulting winds and related hydroelectric and wave energy possibilities. These sources are considered renewable, always available. Fuels resulting from long eras of sunlight, including deposits of coal, oil, and natural gas, are nonrenewable. These resources are depleting on time scales of decades to centuries. Solar radiation is the renewable energy source that is most obviously an opportunity at present to fill the shortfall in energy.

Solar energy, while the basic source of all energy on earth, presently provides only a tiny fraction of utilized energy supply. Global energy usage (global power consumption from all sources) has been estimated as available from the solar radiation falling on 1% of the earth's desert areas. Hence, from a rational and technical point of view there need never be a lack of energy. In recent years, the oil price has been on the order of $100 per barrel, with predictions of prices much higher than the recent peak of $147 per barrel in the span of several years. From the geological point of view, the world's supply of oil is finite, and there is some consensus that in the past 100 years nearly half of it has been used. A long-term energy perspective must be based on long-term resources, and oil is not a long-term resource on a 100-year basis.