Alternative Energy Systemsand Applications

Alternative Energy Systems and Applications

B. K. HodgeMississippi State University, USA

Second Edition

This edition first published 2017 2017 John Wiley & Sons, Ltd

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Library of Congress Cataloging-in-Publication Data

Names: Hodge, B. K., author.Title: Alternative energy systems and applications / B. K Hodge.Description: Second edition. | Hoboken, NJ : John Wiley & Sons, 2017. |

Includes index.Identifiers: LCCN 2016049895| ISBN 9781119109211 (pbk.) | ISBN 9781119109228 (epdf) | ISBN 9781119109235

(epub)Subjects: LCSH: Renewable energy sources. | Power resources. | Electric power

systems.Classification: LCC TJ808 .H63 2017 | DDC 333.79/4–dc23 LC record availableat https://lccn.loc.gov/2016049895

Cover Image: Courtesy of NREL/DOECover Design: Wiley

Set in 10/12pt WarnockPro-Regular by Thomson Digital, Noida, India

10 9 8 7 6 5 4 3 2 1

To Gayle, my wifeAnd best friend

For our family:

Lauren (Hodge) and Adam Sims

Selena and Ben HodgeLiam Finn HodgeNoah Townshend Hodge

vii

Table of Contents

Preface to the Second Edition xiiiPreface to the First Edition xvAbout the Companion Website xvii

1 Energy Usage in the USA and the World 11.1 Energy and Power 11.2 Energy Usage and Standard of Living 11.3 A Historical Perspective of Energy Usage in the USA 41.4 US Energy Usage in 2014 71.5 Worldwide Energy Use 171.6 Efficiencies 191.7 Closure 21

References 21

2 Fundamentals of Turbomachinery 232.1 Definition of a Turbomachine 232.2 Turbomachine Classifications 232.3 Turbomachine Analysis 232.4 Example Problems 282.5 Closure 33

References 33Further Reading 33

3 Hydropower 353.1 Introduction 353.2 Examples of Hydroelectric Dams 353.3 Hydraulic Analysis 393.4 Turbine Specific Speed Considerations 443.5 Energy Transfer in Turbines 483.6 Closure 57

References 60Further Reading 61

4 Wind Energy 634.1 Introduction 634.2 Fundamental Concepts 644.3 Wind Energy Resources 72

viii Table of Contents

4.4 Wind Turbine Operation 784.5 Commercial Wind Turbine Examples 834.6 Growth in Wind Power Capacity 884.7 Closure 90

References 92Further Reading 92

5 Combustion Turbines 935.1 Introduction 935.2 The Combustion Turbine 935.3 The Air-Standard Brayton Cycle 955.4 Actual Gas Turbine Cycle Analysis 965.5 Combustion Turbine Cycle Variations 1045.6 Examples of Commercially Available Combustion Turbines 1055.6.1 Solar Turbines 1065.6.2 GE Energy 1075.6.3 Capstone Turbines 1105.6.4 Other Gas Turbine Suppliers 1125.7 Closure 113

References 113Further Reading 113

6 Solar Energy Fundamentals 1156.1 Introduction 1156.2 Radiation Heat Transfer Review 1156.3 Sun Path Description and Calculation 1266.4 Sun Path Development Using Mathcad 1316.5 The National Solar Energy Database 1376.6 Closure 140

References 140

7 Active Solar Thermal Applications 1437.1 Introduction 1437.2 Flat-Plate Collector Fundamentals 1487.3 Solar Collector and Weather Data 1527.4 The f-Chart Method 1597.5 Other Solar Thermal Systems 1657.6 Closure 166

References 167

8 Passive Solar Energy 1698.1 Fundamental Concepts of Passive Solar Energy 1698.2 Quantifying Passive Solar Features 1728.3 The First-Level Method (Rules of Thumb) 1768.4 The Second-Level Method (the Load Collector Ratio Method) 1778.5 Daylighting 1788.6 Passive Solar Simulation Software 1808.7 Closure 181

References 181

ixTable of Contents

9 Photovoltaic Systems 1839.1 Introduction 1839.2 Photovoltaic Cell Fundamentals 1839.3 Photovoltaic Components 1909.4 Photovoltaic Systems 1969.5 Growth in Photovoltaic Capacity 2019.6 Closure 202

References 203

10 Fuel Cells 20510.1 Introduction 20510.2 Fuel Cell Fundamentals 20510.3 Fuel Cell Thermodynamics Fundamentals 20710.4 Fuel Cell Types 21310.5 Fuel Cell Availability 22010.6 Closure 223

References 223

11 Combined Heat and Power Systems 22511.1 Introduction 22511.2 Combined Heat and Power System Fundamentals 22711.3 Combined Heat and Power System Economics and Operation 23111.4 Economic Assessment of Combined Heat and Power Suitability 23611.5 Thermal and Federal Energy Regulatory Commission Combined Heat and Power

Metrics 24011.6 Combined Heat and Power System Example 24111.7 Closure 245

References 246

12 Biomass 24912.1 Introduction 24912.2 Biomass Availability 25012.3 Biomass Fundamentals 25312.4 Biomass Characteristics 25512.5 Biomass-Based Fuels and Products 25512.5.1 Ethanol 25512.5.2 Methanol 26112.5.3 Biodiesel/Vegetable Oil 26112.5.4 Pyrolysis Liquids 26312.5.5 Biogas 26412.5.6 Producer Gas 26512.5.7 Synthesis Gas 26712.5.8 Biopower and Biofuels Statistics 27012.6 Municipal Solid Waste 27012.7 Closure 278

References 278Further Reading 280

13 Geothermal Energy 28113.1 Introduction 281

x Table of Contents

13.2 Geothermal Resources 28113.3 Geothermal Energy Systems 28613.3.1 Hydrothermal 28613.3.2 Geopressurized 29513.3.3 Magma 29613.3.4 Enhanced Geothermal Systems 29713.4 Geothermal Examples 29713.5 Ground-Source Heat Pumps 30013.6 Closure 304

References 305Further Reading 306

14 Ocean Energy 30714.1 Introduction 30714.2 Ocean Thermal Energy Conversion 30714.2.1 Open Ocean Thermal Energy Conversion Systems 30814.2.2 Closed Ocean Thermal Energy Conversion Systems 31214.2.3 Hybrid Ocean Thermal Energy Conversion Systems 31514.2.4 Ocean Thermal Energy Conversion System Outputs 31514.2.5 Ocean Thermal Energy Conversion Assessment 31514.3 Tidal energy 31914.4 Marine and Hydrokinetic Energy 32414.4.1 Rotating devices 33014.5 Closure 331

References 332

15 Nuclear Energy 33315.1 Introduction 33315.2 Fundamentals of Nuclear Energy 33415.3 Nuclear Power 33915.3.1 Chernobyl 34815.3.2 Fukashima Daiichi 35015.3.3 Nuclear Power in the Twenty-First Century 35115.4 Fusion Power 35415.5 Closure 359

References 359

16 Transportation and Hybrid and Electric Vehicles 36116.1 Transportation Energy Usage Alternatives to Internal Combustion Engines 36116.2 Hybrid and Electric Vehicles 36416.3 Hybrid and Electric Vehicles Past, Present, and Future 37016.4 Closure 375

References 375

17 Hydraulic Fracturing, Oil, Natural Gas, and the New Reality 37717.1 Introduction 37717.2 Unconventional Oil and Gas 37717.3 Reservoir Engineering Concepts 38117.4 Oil and Gas Recovery from Tight Plays 38617.5 The New Reality 392

xiTable of Contents

17.6 Closure 399References 399Further Reading 400

Appendix A 401Appendix B 415

Index 431

xiii

Preface to the Second Edition

Since the first edition was written (2007–2009), many changes in the energy posture of the USAas well as the rest of the world have taken place. The second edition has been significantlyinfluenced by these changes. Two chapters have been added: one addressing electric and hybridvehicles (Chapter 16) and one examining enhanced oil and gas recovery (via hydraulicfracturing) and its ramifications (Chapter 17). All of the chapters have been revised andmodernized and have had, in many instances, substantial additions. When possible, quantitativeinformation has been updated to the current data available. These data include documentedenergy usages, energy resource/usages projections, and energy systems’ and components’performance metrics and availability. The number of web sites cited in the second edition issubstantially greater than in the first edition. All cited web sites were active as of December 2016.However, web sites are updated (and renamed) frequently, but using a search engine with areasonably complete descriptor will usually redirect to an appropriate site. Since the first edition,useful quantitative information in many company and government agency web sites has beenreduced in favor of more words, pictures and illustrations. If sufficient quantitative informationis not available on a company/agency web site, queries to that company/agency will often resultin securing such metrics.

The theme of the first edition, namely alternative energy sources and the alternative use ofexisting energy sources, has been continued in the second. Chapter 16, Transportation andHybrid and Electric Vehicles, was added because electric and hybrid vehicles offer alternativesand efficiency enhancements to conventional internal combustion engine powered vehicles.Chapter 17, Hydraulic Fracturing, Oil, Natural Gas, and the New Reality, was added becauseenhanced oil and gas recovery has dramatically shifted the energy posture/outlook of manycountries. Every topic has been impacted by advances in technology and changes in emphasis.Examples include consideration of new installed hydroelectric capacity, significant increase inwind energy installed capacity, backlog for combustion turbine orders, growth in solar thermalusage, recognition of passive solar advantages, decreasing photovoltaic cell cost per kilowattenhancing economic attractiveness, advances in fuel cell commercialization, combined heat andpower industrial/commercial market penetration, biofuels focus areas diversity, geothermalenergy successes and advances, ocean energy potential recognition, renewed interest in nuclearpower, hybrid/electric vehicle sales up, and hydraulic fracturing impacts. Since the first edition,the energy concerns of the USA have to some extent diminished, but technically, politically,environmentally, and economically, energy issues, including climate change, have become moredivisive. Indeed, in the year 2000 few predicted that the USA would dramatically reduce itsenergy imports and, perhaps, even become an energy exporting nation.

Enhanced oil and gas recovery has resulted in unexpected increases in domestic fossil fuelproduction and in the proved reserves of both crude oil and natural gas. However, even ifenhanced oil and gas recovery were to provide, in the short term, acceptable energy resourcesfor the USA and the rest of the world, other considerations (greenhouse gas emissions,

xiv Preface to the Second Edition

environmental effects, climate change, long-term availability, for example) require that alter­native energy sources and alternative uses of existing resources be a part of meeting futureenergy requirements. Hence, the topics of this textbook are very germane for the future. Theidentification of additional fossil fuel resources has essentially provided more time to discover,implement, and develop other, more sustainable and more environmentally-friendly energyresources.

Review questions and exercises, at the end of each chapter in the first edition, are available onthe companion web site for this book rather than at the end of each chapter.

I appreciate all the comments, corrections, and suggestions for the first edition received fromcolleagues. The corrections were implemented and the comments and suggestions consideredfor the second edition.

Additionally, thanks are due to Professors Tejas S. Pandya, Paul Stewart, SangarajuShanmugam, Samuel Sih, Xianchang Li and Alison Subiantoro who reviewed the manuscript;their comments were insightful and helpful.

B.K. HodgeMississippi State University

January 2017

xv

Preface to the First Edition

In recent years much has been made of the impact of the myriad energy problems faced not onlyby the United States, but also the rest of the world. These impacts range from energy securityissues (the dependence on imported energy sources) to economic issues (gasoline reached$4.00/gallon in the summer of 2008) to energy sustainability issues (minimum environmentaland ecological impacts). Many in the engineering, corporate, and political communitiesadvocate greater reliance on alternative energy sources. Because of the increased interests insuch topics, a number of books on subjects ranging from sustainable energy to renewable energyto alternative energy have been offered in recent years. However, many of these books containmostly qualitative information with little in the way of quantitative information or “engineering”calculations or procedures. Some also advocate specific alternative energy scenarios and somedo not present balanced discussions. This textbook was written to address the above concerns.Alternative Energy Systems and Applications is suitable for use at the senior or beginning

graduate level for students in mechanical engineering or in energy-engineering related fields.Familiarity with the basic concepts of fluid mechanics, thermodynamics, and heat transfer ispresumed in the development of the topics in the book, but maturity in these subjects is notneeded in order to understand the developments.

The title, Alternative Energy Systems and Applications, is used to convey the idea that thetopics covered encompass both alternative energy sources and alternative uses of existingenergy sources. The solution to the current energy dilemma will contain features of both. Thebreadth of topics proposed for the book is delineated in the chapter headings. Chapter 1critically examines energy usage in the United States. Although not explicitly subdivided intocongruent topical areas, Chapters 2–5 treat turbomachine-based topics (hydro, wind, andcombustion turbines), Chapters 6–9 consider solar-based topics (active, passive, and photo­voltaic), Chapters 10–11 examine fuel cells and CHP (combined heating and power) applica­tions, and Chapters 12–15 complete the review of alternative energy concepts (biomass,geothermal, ocean, and nuclear).

All chapters except chapter 1 broadly fit into one of two categories—(1) a review of thebackground information necessary for a topic or (2) an exploration of an alternative energysource or an alternative use of an existing energy source. Chapters 2 and 6, for example, are usedto review the backgrounds necessary for turbomachines and solar energy, respectively.

Often alternative energy topics are equated to renewable energy resource discussions. In thisbook, Chapters 3–4 and 7–9 consider topics usually associated with renewable energyresources.The chapters dealing with renewable energy topics present the physical principlesinvolved in harvesting the renewable, review (in most cases) the amount of the renewableresource available, examine quantitative aspects of the harvesting, point out difficulties withutilizing the renewable resource, discuss limitations and economics aspects, and provide, ifapplicable, examples of commercial systems for harvesting the renewable. Where appropriate,website addresses are cited.

xvi Preface to the First Edition

The chapters addressing alternative uses of existing energy sources are focused on applica­tions. Combustion turbines, fuel cells, and CHP systems represent alternative uses of existingenergy sources.The application chapters basically discuss the operation, the thermodynamicaspects, and the expected efficiencies of such systems and provide examples. As with therenewable energy topics, suitable websites are referenced.

All chapters, except Chapter 1, contain worked examples and review questions and exerciseproblems. The focus is on first-order engineering calculations. Mathcad® is used as thecomputational software system throughout the book. However, the examples/problems arefundamental, and many other computational systems (MATLAB®, EES, Mathematica®) couldbe readily adopted for use with little effort. The intent of the book is to provide students with aquantitative approach to alternative energy sources and alternate applications of existing energysources. Since this is a survey textbook, it does not attempt to provide detailed engineeringinformation on the topics discussed, but references are provided that do contain detailedengineering information.

This textbook is the outgrowth of several years of teaching ME 4353/6353 Alternate EnergySources in the Bagley College of Engineering at Mississippi State University. The discretionaryfunds provided to me as holder of the Tennessee Valley Authority Professorship in EnergySystems and the Environment at Mississippi State University were very helpful in this endeavorand are acknowledged. Additionally, thanks are due to Professors Francis Kulacki, JamesMathias, and David Ruzic who reviewed the manuscript.Their comments and insights werequite useful.

B. K. HodgeMississippi State University

January 2009

xvii

About the Companion Website

Alternative Energy Systems and Applications Second Edition is accompanied by a companionwebsite:

www.wiley.com\go\Hodge\AESystemsandApplications2E

The website includes:

� Solutions manual

1

1

Energy Usage in the USA and the World

1.1 Energy and Power

A review of the customary units used for energy and power is appropriate to initiate a study ofalternative energy sources and applications. Although much of the world uses the SI system(Le Système International d’Unités), the USA, in addition to the SI system, also uses the EnglishEngineering and the British Gravitational systems of units. The unit of energy in the SI system isthe newton meter (N m) which is defined as the joule (J). Energy in the English Engineeringsystem is defined as the British thermal unit (Btu), or alternately, the foot-pound force (ft lbf);the conversion factor is 1 Btu � 778:16 ft lbf . Power is the rate of energy usage or transfer, injoules per second, British thermal units per second, or foot-pound force per second. Powerexpressed in joules per second is defined as the watt (W). The most frequently used power unitis 1000 W or 1 kW. In the USA, power is sometimes expressed in terms of horsepower (hp),where 1 hp is 550 ft lbf/s or 0.7457 kW. The kilowatt-hour (kW h) is a frequently used unit ofenergy and represents an energy rate (kilowatts) times a time (hour). The conversion is3412:14 Btu � 1 kW h. Anyone engaged in an energy engineering activity needs to rememberthe conversion between British thermal units and kilowatt-hours; in most instances 3412 Btu �1 kW h is used.

Tester et al. (2012) provide a sampling of power expended for various activities. Some of theirresults are reproduced as Table 1.1.

The range of power expended is astonishing, about nine orders of magnitude. The entries ofTable 1.1 indicate various levels of power expended referenced to everyday experiences and canbe used to establish a sense of numeracy for power magnitudes.

1.2 Energy Usage and Standard of Living

An irrefutable fact is that developed countries (e.g., USA, Japan, UK) use more energy per capitathan less-developed countries (e.g., Mexico, Indonesia). Figure 1.1 graphically presents the HDI(Human Development Index) as a function of the kilograms of oil equivalent (kgoe) per capitaper year. The HDI is a measure of the standard of living, and the kilograms of oil equivalent percapita per year is indicative of the energy consumption. The industrialized nations have HDIvalues in excess of 0.9, while many of the developing countries’ HDI values are dramatically less.The correlation between HDI and kilowatt-hour usage is functionally very strong. However,once a threshold of about 3000 kgoe per capita is reached, further increases in electricity usagedo not produce a higher HDI. Iceland has the highest HDI, followed by the USA. Some countrieswith the higher kilowatt-hour usage have large infrastructure length scales and traditions ofabundant energy. One of the main themes from Golemberg and Johansson (2004) is that theonly way to increase the HDI in developing nations is to increase their energy usage.

Alternative Energy Systems and Applications, Second Edition. B. K. Hodge.© 2017 John Wiley & Sons, Ltd. Published 2017 by John Wiley & Sons, Ltd.Companion website: www.wiley.com\go\Hodge\AESystemsandApplications2E

2 Alternative Energy Systems and Applications

Table 1.1 Power expended for various activities.

Activity Power expended

Pumping human heart 1:5 W � 1:5 � 10�3 kW

Household light bulb 100 W � 0:1 kW

Human, hard work 0.1 kW

Draft horse 1 kW

Portable floor heater 1.5 kW

Compact automobile 100 kW

SUV 160 kW

Combustion turbine 5000 kW � 5 MW

Large ocean liner 200 000 kW � 200 MW�0:2 GW

Boeing 747 at cruise 250 000 kW � 250 MW � 0:25 GW

Coal-fired power plant 1 � 106 kW � 1000 MW � 1 GW

Niagara Falls hydroelectric plant 2 � 106 kW � 2000 MW � 2 GW

An alternative approach is to examine the gross national product (GNP) per capita as a functionof the energy consumption per capita. Figure 1.2a was developed using World Bank informationfrom 1992. Figure 1.2b was developed from more recent World Bank data. The more recent datawere mostly from 2012–2013, although data from some developing countries were less recent.

Figure 1.1 Human Development Index (HDI) as a function of per capita kilowatt-hour consumption.Source: Golemberg and Johansson (2004). Reproduced with permission of UNDP.

31 Energy Usage in the USA and the World

Figure 1.2 Per capita energy consumption versus GNP per capita for a number of countries. (a) 1992World Bankdata. Source: Tester et al. (2005). (b) Recent World Bank data (www.worldbank.org, 2012–2013).

The energy usage per capita information from the World Bank is presented in kilograms of oilequivalent per capita; hence, the ordinates for Figure 1.2a and b are in different energy units andthe abscissas, in dollars, are not adjusted for inflation. A comparison of Figure 1.2a and b reveals nosignificant differences in relative positions for the developed countries, but China has made realgains in GNP per capita since the 1992 data, and, as expected, the energy use per capita hasincreased relative to other developing countries since 1992. In Figures 1.1 and 1.2, the USAexhibits per capita kilowatt-hours and energy usages that are large even for developed countries.A number of reasons exist for the high energy consumption per capita in the USA; among them are(1) historically cheap energy, (2) low population density, (3) large area (large infrastructure lengthscale), and (4) historically an abundance of domestic energy.

Starting with the first “energy crisis” of the late 1970s, low energy costs and domestic energyabundance seemingly vanished from the USA. From the 1970s through to about 2005, theUSA required increasing energy imports (chiefly in the form of petroleum) and nearly

4 Alternative Energy Systems and Applications

monotonic energy cost price escalations. The dependence on energy imports dramaticallyaffected both the economy and the foreign policy posture of the USA. Indeed, the basis of thefirst edition of this textbook was the need to consider both alternative energy sources andalternative (read more efficient utilization) energy applications to address the energyproblems faced in the USA. Since about 2005, increased domestic production of fossil fuels(by enhanced oil recovery via “hydraulic fracturing”) and identification of heretoforeundiscovered natural gas reserves have altered the expected increases in both energy importsand energy prices. In effect, the US energy economy is being given another chance to reduceenergy cost economic impacts via enhanced energy efficiency of existing resources.Chapter 17 examines this topic.

The energy problems in the USA are exacerbated by the demand and expectation of countries(e.g., India and China) to increase the standard of living for their citizens. World energyconsumption is rising faster than energy consumption in the USA. Section 1.5 examines worldenergy consumption patterns.

1.3 A Historical Perspective of Energy Usage in the USA

The Energy Information Administration (EIA) of the US Department of Energy provides a readilyaccessible and up-to-date source of energy statistics. The EIA web site is www.eia.doe.gov.The EIA provides on a timely basis monthly and yearly energy statistics for the USA. Thesemonthly energy statistics are available in the Monthly Energy Review (MER), and a yearlyenergy summary appears in the Annual Energy Review (AER) about 8 months after the endof the calendar year and can be accessed from www.eia.doe.gov/aer. As of 2012, the AERhas been suspended because of budget concerns. The suspension of the AER is quiteunfortunate as it was arguably the most useful of the EIA periodic documents. The basis forthe information contained herein is from the MERs available online at www.eia.gov/totalenergy/data/monthly/.

Figure 1.3, a mosaic of satellite photographs at night of the USA, is a rather dramaticillustration of the population density and dispersion of the population of the USA as well as theenergy intensity distribution of night lighting (primarily electricity usage).

Figure 1.3 Mosaic of night satellite photographs of the USA. Source: EIA.

51 Energy Usage in the USA and the World

Figure 1.4 Historical energy utilization in the USA (1775–2012). Source: EIA.

Consider how the USA arrived at its current energy economy. Figure 1.4, taken from the EIAdata, presents a graphical representation of the historical energy utilization. The energy usageunit used is the quad (quadrillion Btu is 1015 Btu). Until the mid-1800s, energy utilization wasmostly wood, with coal becoming increasingly important after 1850. By 1900, coal usage wasmuch greater than wood, and petroleum was becoming more important as an energy source.And in 1950, petroleum usage exceeded coal usage, and natural gas usage was dramaticallyrising. At the millennium, petroleum provided the most energy, with natural gas and coal vyingfor second and third place. Nuclear power was in fourth place, with hydroelectric and renewableenergy (including wood) sources making the smallest contributions. Details of the energyutilization in 2014 will be explored in Section 1.4.

The genesis of the energy problem is illustrated in Figure 1.5. Until about 1950, the USA hadlittle dependence on energy imports. However, with the post-World War II prosperity, energyexports began to increase since consumption increased faster than domestic production. Fromthe 1980s to the early 2000s, domestic production increased, but at a rate slower thanconsumption increased. The result has been a steady increase in energy imports. However,starting about 2005, as demonstrated in Figure 1.6, the result of enhanced domestic productionhas resulted in a significant decrease in energy-related imports. Much of the increased

Figure 1.5 Energy consumption, imports, and exports for the USA. Source: EIA.

6 Alternative Energy Systems and Applications

Figure 1.6 Energy imports since 1975. Source: EIA.

production has resulted from enhanced oil production from existing oil fields using hydraulicfracturing techniques (see Chapter 17).

Further understanding of how the USA arrived at the current energy consumption isprovided in Figures 1.7 and 1.8. Figure 1.7 tracks the per capita energy consumption. Percapita energy consumption reached 344× 106 Btu/person in 1980, decreased until 1985, andreached a peak at 346× 106 Btu/person in 1995. Much of the behavior during the 1970s and1980s was the response to the first “energy crisis.” Since 2005, the energy usage per capita hasdecreased, with the result that in 2014 the per capita energy consumption was 309 × 106 Btu/person. The 1970s energy crisis resulted in no dramatic decrease in per capita energyconsumption in the USA; these results explain, in part, the current energy dilemma ofthe USA. In short, the USA failed to understand and heed the warnings of the first energycrisis. The energy usage per dollar of gross domestic product (GDP) is presented in Figure 1.8.Since the 1980s, the energy consumed per dollar of GDP has meaningfully declined from near12 000 Btu/$GDP to the current value of 6120 Btu/$GDP (per chained 2009 dollar). Chaineddollars are dollars that are adjusted to reflect inflation, “chained” to a base year (2009 in thiscase). This decline is attributed to increased energy efficiency, especially in manufacturing,and to structural changes (the migration of much energy-intensive industry to othercountries) in the economy.

Figure 1.7 Historical per capita energy consumption in the USA. Source: EIA.

71 Energy Usage in the USA and the World

Figure 1.8 Energy consumption per real dollar of GDP. Source: EIA.

1.4 US Energy Usage in 2014

The EIA energy flow diagram for 2014, from the EIA Total Energy (EIA, 2015), is arguably themost informative graphical representation provided by the EIA and is reproduced as Figure 1.9.In this figure, all energy usages are in quads (1015 Btu). Energy sources are delineated on the left-hand side of the diagram (e.g., coal at 20.26 quad). The sources are then summed and expressedas domestic production (87.04 quad) and imports (23.31 quad). The total supply is 110.55 quadwith exports of 12.22 quad, which yields 98.32 quad for consumption. The end-point energyusages (categorized as residential, commercial, industrial, and transportation) are shown on theright-hand side of the figure. Thus, in 2014, the US energy economy was 98.32 quad of which23.31 quad was imported. A different perspective of the energy flow diagram is presented inFigure 1.10, which delineates the connection between energy sources and end-point energyusages expressed in two different ways: in Figure 1.10a as “transportation,” “industrial,”“residential and commercial,” and “electric power,” and in Figure 1.10b as the more conven­tional four, “transportation,” “industrial,” “residential,” and “commercial.” The conventionalfour end-point energy usages are displayed on a pie chart in Figure 1.11b. Industrial usageaccounts for 32% of the total energy used, followed by 28% for transportation. The remainder isalmost evenly split between residential and commercial. Since the energy used by no end-usesector is dominant, alternative sources and applications are needed for all end-use sectors ifsignificant reductions in energy uses are to be forthcoming. Figure 1.10a is especially interestingsince it directly connects, with percentages indicated, energy sources and end-point energyusages. Mastery of the information in Figures 1.9 and 1.10 is necessary if energy usage in theUSA is to be completely understood.

In 2014, renewable energy from all sources contributed about 10% of the total energy utilizedin the USA. Figure 1.11 itemizes the percentage contribution of renewable energy sources in theUSA for 2014. Perhaps the most amazing statistic is that wood and conventional hydroelectricpower accounted for 49% of the total renewable energy that year! Solar and wind contributed22% of the total renewable energy (or about 2% of the total energy consumption) in 2014. Hence,in spite of much interest and media hype, the penetration of solar and wind energy into theenergy mix has not made much progress.

Renewable energy sources have increased in recent years. Figure 1.12 illustrates the contri­butions of various renewable energy sources since 2000. Hydropower has fluctuated, whilebiomass and geothermal have exhibited slight increases. But since 2000 wind power hasdramatically increased and is now the second largest renewable source after hydropower. Solarhas also grown, but not nearly at the rate of wind power. Wind power and hydropowercombined to contribute about 87% of the total renewable energy production (excluding

8 Alternative Energy Systems and Applications

Figure 1.9 US energy flow diagram (quadrillion Btu) for 2014. Source: EIA.

91 Energy Usage in the USA and the World

Figure 1.10 End-use energy utilizations in 2014. Source: EIA. (a) End-point energy usages (quadrillion Btu) with electric power separate. (b) End-point energy usageswith electric power included in the primary four.

10 Alternative Energy Systems and Applications

Figure 1.10 (Continued)

biomass) in 2014. Subsequent chapters of this book will examine in more detail hydropower,wind power, solar/photovoltaic, biomass, geothermal, and municipal solid waste as well as oceanenergy, combined heat and power, and nuclear (not an alternative or renewable energy, but onethat must be considered because of its potential). A very comprehensive study of electricitygenerated from renewable resources was developed by the National Academy of Sciences et al.(2010). The title of the study is Electricity from Renewable Resources: Status, Prospects, and

Figure 1.11 Percentage contributions of renewable energy sources in 2014. Source: EIA.