Wind Energy, Renewable Energy and the Environmment

Power Transmission Design and Engineering

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Open: Wind Energy, Renewable Energy and the Environmment

The big question: How do we use science and technology such that Spaceship Earth will be a place for all life to exist? We are citizens of the planet Earth, and within your lifetime there will be major decisions over the following: energy (including food), water, minerals, space, and war (which I can state will happen with 99.9% probability). The previous statements were written over 20 years ago when I first taught introductory courses on wind and solar energy. Since then the United States has been involved in Grenada, Panama, Somalia, the Gulf War, the Balkans, Afghanistan, and now Iraq, so the prediction on war was easily fulfilled. I refer to two of the wars as Oil War I (the Gulf War) and Oil War II (Iraq War).

We are over 6 billion and heading toward 11 billion people. Renewable energy is part of the solution for the energy problem, and wind energy is one of the cost-effective options for the generation of electricity. By the end of 2007, there were around 100,000 wind turbines installed in wind farms (also called parks or plants), with an installed capacity of 94,000 megawatts, which generated around 300 terawatt-hours in a year. Wind energy is now part of national policies for generation of electricity

I was very fortunate to work in a new field, which allowed research, publication and travel, and interaction with scientists, engineers, manufacturers, policy makers, and students that has enriched my life. I enjoyed visiting the wind farms, installations, universities, and institutes in many parts of the world. It is a pleasure to get paid for something you like to do.

I am deeply indebted to colleagues, present and past, at the Alternative Energy Institute (AEI); West Texas A&M University (WTAMU); the Wind Energy Group at the Agricultural Research Service; the U.S. Department of Agriculture (USDA), Bushland, Texas; and the students in my classes and those who have worked at AEI who have provided insight and feedback. There are many others who have worked with us at AEI and USDA, especially the numerous international researchers and interns. Thanks also to the Instruction Innovation and Technology Laboratory, WTAMU, for the computer drawings. I want to express gratitude to my wife, Beth, who has put up with me all these years. Even though if you have seen one wind turbine or wind fa

Abbas Ghassemi, PhD

TOC

Series Preface .................................................................................................................................xi
The Series Editor .......................................................................................................................... xv Preface..........................................................................................................................................xvii
The Author....................................................................................................................................xix

Chapter 1 Introduction......................................................................................................................................1
1.1 History.................................................................................................................................1 1.1.1
Dutch Windmill.....................................................................................................1 1.1.2
Farm Windmill ......................................................................................................2 1.1.3
Wind Chargers.......................................................................................................4 1.1.4
Generation of Electricity for Utilities ...................................................................5 1.2
Wind Farms .......................................................................................................................10 1.3
Small Systems ...................................................................................................................11
Links............................................................................................................................................11
References...................................................................................................................................11

Chapter 2 Energy ............................................................................................................................................. 13
2.1 Philosophy.........................................................................................................................13
2.1.1 Advantages/Disadvantages of Renewable Energy ..............................................13
2.1.2 Economics...........................................................................................................13
2.2 Definition of Energy and Power........................................................................................14
2.3 Fundamentals Concerning Energy ....................................................................................15
2.4 Energy Dilemma in Light of the Laws of Thermodynamics.............................................16
2.4.1 Conservation........................................................................................................16
2.4.2 Efficiency ............................................................................................................16
2.5 Exponential Growth ..........................................................................................................18
2.6 Use of Fossil Fuels............................................................................................................21
2.6.1 Oil and Natural Gas.............................................................................................21
2.6.2 Coal .....................................................................................................................23
2.7 Nuclear ..............................................................................................................................24
2.8 Mathematics of Exponential Growth ................................................................................25
2.8.1 Doubling Time ....................................................................................................25
2.8.2 Resource Consumption .......................................................................................25
2.9 Lifetime of a Finite Resource............................................................................................26
2.10 Summary ...........................................................................................................................27
Links............................................................................................................................................28
References...................................................................................................................................28
General ........................................................................................................................................29
Questions/Activities ....................................................................................................................29
Order of Magnitude Estimates ....................................................................................................30
Problems......................................................................................................................................30

Chapter 3 Wind Characteristics..................................................................................................................... 33
3.1 Global Circulation.............................................................................................................33
3.2 Extractable Limits of Wind Power....................................................................................33
3.3 Power in the Wind.............................................................................................................35
3.4 Wind Shear........................................................................................................................37
3.5 Wind Direction..................................................................................................................41
3.6 Wind Power Potential........................................................................................................41
3.7 Turbulence.........................................................................................................................43
3.8 Wind Speed Histograms....................................................................................................44
3.9 Duration Curve..................................................................................................................45
3.10 Variations in Wind Power Potential ..................................................................................46
3.11 Wind Speed Distributions .................................................................................................48
3.12 General Comments............................................................................................................49
Links............................................................................................................................................49
References...................................................................................................................................49
Questions/Activities ....................................................................................................................50
Problems......................................................................................................................................50

Chapter 4 Wind Resource ............................................................................................................................... 53
4.1 United States .....................................................................................................................54
4.2 European Union ................................................................................................................57
4.3 Other Countries .................................................................................................................58
4.4 Ocean Winds .....................................................................................................................59
4.4.1 Texas Gulf Coast .................................................................................................61
4.4.2 World...................................................................................................................61
4.5 Instrumentation .................................................................................................................61
4.5.1 Cup and Propeller Anemometers ........................................................................63
4.5.2 Wind Direction....................................................................................................65
4.5.3 Instrument Characteristics...................................................................................66
4.5.4 Measurement.......................................................................................................66
4.5.5 Vegetation Indicators...........................................................................................67
4.6 Data Loggers .....................................................................................................................70
4.7 Wind Measurement for Small Wind Turbines...................................................................71
Links............................................................................................................................................71
Maps..................................................................................................................................71
Ocean Winds .....................................................................................................................71
References...................................................................................................................................72
Problems......................................................................................................................................73

Chapter 5 Wind Turbines................................................................................................................................ 75
5.1 Drag Device.......................................................................................................................75
5.2 Lift Device.........................................................................................................................75
5.3 Orientation of the Rotor Axis............................................................................................78
5.4 Description of the System .................................................................................................80
5.5 Aerodynamics ...................................................................................................................81
5.6 Control...............................................................................................................................84
5.6.1 Normal Operation................................................................................................85
5.6.2 Faults...................................................................................................................86
5.7 Energy Production.............................................................................................................86
5.7.1 Generator Size.....................................................................................................86
5.7.2 Rotor Area and Wind Map ..................................................................................87
5.7.3 Manufacturer's Curve..........................................................................................88
5.8 Calculated Annual Energy.................................................................................................88
5.9 Innovative Wind Systems..................................................................................................89
5.10 Applications ......................................................................................................................95
5.10.1 Electrical Energy.................................................................................................95
5.10.2 Mechanical Energy..............................................................................................96
5.10.3 Thermal Energy...................................................................................................96
5.10.4 Wind Hybrid Systems .........................................................................................96
5.10.5 Summary .............................................................................................................97
5.11 Storage...............................................................................................................................97
Links............................................................................................................................................97
References...................................................................................................................................97
Problems......................................................................................................................................98

Chapter 6 Design of Wind Turbines............................................................................................................. 101
6.1 Introduction.....................................................................................................................101
6.2 Aerodynamics .................................................................................................................101
6.3 Mathematical Terms........................................................................................................102
6.4 Drag Device.....................................................................................................................103
6.5 Lift Device.......................................................................................................................104
6.5.1 Maximum Theoretical Power............................................................................107
6.5.2 Rotation.............................................................................................................108
6.6 Aerodynamic Performance Prediction ............................................................................108
6.7 Measured Power and Power Coefficient .........................................................................115
6.8 Construction ....................................................................................................................117
6.8.1 Blades................................................................................................................117
6.8.2 Rest of the System.............................................................................................122
6.9 Evolution .........................................................................................................................125
6.10 Small Wind Turbines.......................................................................................................127
References.................................................................................................................................128
Problems....................................................................................................................................130

Chapter 7 Electrical....................................................................................................................................... 133
7.1 Fundamentals ..................................................................................................................133
7.1.1 Faraday's Law of Electromagnetic Induction ...................................................136
7.1.2 Phase Angle and Power Factor..........................................................................136
7.2 Generators .......................................................................................................................138
7.2.1 Induction Generator, Constant-RPM Operation................................................139
7.2.2 Doubly Fed Induction Generator, Variable-RPM Operation.............................142
7.2.3 Direct-Drive Generator, Variable-RPM Operation............................................143
7.2.4 Permanent Magnet Alternator, Variable-RPM Operation .................................143
7.2.5 Generator Comparisons.....................................................................................143
7.2.6 Generator Examples..........................................................................................144
7.3 Power Quality..................................................................................................................145
7.4 Electronics.......................................................................................................................147
7.4.1 Controllers.........................................................................................................147
7.4.2 Power Electronics..............................................................................................149
7.4.3 Inverters.............................................................................................................150
7.5 Lightning.........................................................................................................................150
7.6 Resistance Dump Load ...................................................................................................150
Links..........................................................................................................................................151
References.................................................................................................................................151
Problems....................................................................................................................................151

Chapter 8 Performance ................................................................................................................................. 153
8.1 Measures of Performance................................................................................................153
8.2 Windstats.........................................................................................................................155
8.3 Wind Farm Performance .................................................................................................155
8.3.1 California Wind Farms......................................................................................155
8.3.2 Other Wind Farms in the United States.............................................................157
8.3.3 Other Countries .................................................................................................158
8.4 Wake Effects....................................................................................................................160
8.5 Enertech 44......................................................................................................................161
8.6 Bergey Xcel.....................................................................................................................164
8.7 Water Pumping................................................................................................................165
8.7.1 Farm Windmill ..................................................................................................166
8.7.2 Electric to Electric.............................................................................................166
8.8 Wind-Diesel and Hybrid .................................................................................................167
8.9 Blade Performance..........................................................................................................169
8.9.1 Surface Roughness............................................................................................169
8.9.2 Boundary Layer Control ...................................................................................172
8.9.3 Vortex Generators..............................................................................................173
8.9.4 Flow Visualization.............................................................................................174
8.10 Comments .......................................................................................................................175
Links..........................................................................................................................................175
References.................................................................................................................................175
Problems....................................................................................................................................176

Chapter 9 Siting ............................................................................................................................................. 179
9.1 Small Wind Turbines.......................................................................................................179
9.1.1 Noise .................................................................................................................181
9.1.2 Visual Impact ....................................................................................................183
9.2 Wind Farms .....................................................................................................................184
9.2.1 Long-Term Reference Stations .........................................................................184
9.2.2 Siting for Wind Farms.......................................................................................184
9.3 Digital Maps....................................................................................................................185
9.4 Geographic Information Systems....................................................................................186
9.5 Wind Resource Screening ...............................................................................................187
9.5.1 Estimated Wind Power for Texas, Pacific Northwest Labs...............................187
9.5.2 Estimated Wind Power for Texas, Alternative Energy Institute........................189
9.5.3 Wind Power for the United States.....................................................................190
9.6 Numerical Models...........................................................................................................191
9.7 Micrositing ......................................................................................................................192
9.8 Ocean Winds ...................................................................................................................196
9.9 Summary .........................................................................................................................196
Links..........................................................................................................................................197
References.................................................................................................................................197
Geographic Information Systems..............................................................................................198
Problems....................................................................................................................................198

Chapter 10 Applications and Wind Industry................................................................................................ 201
10.1 Utility Scale.....................................................................................................................201
10.2 Small Wind Turbines.......................................................................................................202
10.3 Distributed Systems ........................................................................................................204
10.4 Wind-Diesel ....................................................................................................................206
10.5 Village Power ..................................................................................................................209
10.5.1 China .................................................................................................................211
10.5.2 Case Study: Wind Village Power System..........................................................212
10.6 Water Pumping................................................................................................................213
10.6.1 Design of Wind Water Pumping System...........................................................214
10.6.2 Large Systems ...................................................................................................216
10.7 Wind Industry..................................................................................................................216
10.7.1 Wind Industry, 1980–1990................................................................................219
10.7.2 Wind Industry, 1990–2000................................................................................220
10.7.3 Wind Industry, 2000–2010................................................................................221
10.8 Comments .......................................................................................................................222
Links..........................................................................................................................................223
References.................................................................................................................................224
Problems....................................................................................................................................226

Chapter 11 Institutional ..................................................................................................................................227
} 11.1 Avoided Costs .................................................................................................................227
11.2 Utility Concerns ..............................................................................................................228
11.2.1 Safety.................................................................................................................228
11.2.2 Power Quality....................................................................................................229
11.2.3 Connection to the Utility...................................................................................229
11.2.4 Ancillary Costs..................................................................................................229
11.3 Regulations on Installation and Operation......................................................................230
11.4 Environment....................................................................................................................230
11.5 Politics.............................................................................................................................233
11.6 Incentives ........................................................................................................................234
11.6.1 United States .....................................................................................................234

11.6.1.1 State Incentives..............................................................................236
11.6.1.2 Green Power ..................................................................................237
11.6.1.3 Net Metering..................................................................................237
11.6.2 Other Countries .................................................................................................237
11.7 Externalities.....................................................................................................................239
11.8 Transmission ...................................................................................................................240
Links..........................................................................................................................................240
References.................................................................................................................................241
Problems....................................................................................................................................243

Chapter 12 Economics.....................................................................................................................................245
12.1 Factors Affecting Economics ..........................................................................................245
12.2 General Comments..........................................................................................................246
12.3 Economic Analysis..........................................................................................................247
12.3.1 Simple Payback.................................................................................................248
12.3.2 Cost of Energy...................................................................................................249
12.3.3 Value of Energy.................................................................................................251
12.4 Life Cycle Costs..............................................................................................................251
12.5 Present Worth and Levelized Costs.................................................................................253
12.6 Externalities.....................................................................................................................254
12.7 Wind Project Development .............................................................................................255
12.7.1 Costs..................................................................................................................258
12.7.2 Benefits..............................................................................................................259
12.7.3 Sale of Electricity..............................................................................................259
12.8 Hybrid Systems ...............................................................................................................260
12.8 Summary .........................................................................................................................262
12.9 Future ..............................................................................................................................264
Links..........................................................................................................................................264
References.................................................................................................................................264
Problems....................................................................................................................................265

Wind Solutions.............................................................................................................................269
Chapter 2 ...................................................................................................................................269
Questions/Activities ........................................................................................................269
Problems..........................................................................................................................270
Chapter 3 ...................................................................................................................................273
Chapter 4 ...................................................................................................................................277
Chapter 5 ...................................................................................................................................280
Chapter 6 ...................................................................................................................................282
Chapter 7 ...................................................................................................................................287
Chapter 8 ...................................................................................................................................289
Chapter 9 ...................................................................................................................................291
Chapter 10 .................................................................................................................................294
Chapter 11 .................................................................................................................................295
Chapter 12 .................................................................................................................................296