Wind Energy Explained

James Manwell is a professor of Mechanical Engineering the University of Massachusetts and the Director of the Wind Energy Center there. He hold an M.S. in Electrical and Computer engineering and a Ph.D. in Mechanical Engineering. he has been involved with a wide range of wind energy research areas since the mid 1970's. These range from wind turbine dynamics to wind hybrid power systems. His most recent research has focused on the assessment of external conditions related to the design of offshore wind turbines. he has participated in activities of the International Energy Agency, the International Electrotechnical Commission and the International Science Panel on Renewable Energies. He lives in Conway, Massachusetts. John McGowan a professor Mechanical Engineering at the University of Massachusetts and the co-Director of the Wind Energy Center there. He holds an M.S. and a Ph.D. in Mechanical Engineering. During his forty plus years at the University he has developed and taught a number of fundamental undergraduate/graduate engineering courses in renewable energy and energy conversion. His research and graduate student supervision at UMass has produced approximately 200 technical papers in a wide range of energy conversion applications. His recent research interests in wind engineering have been concentrated in the areas of wind system siting, hybrid systems modeling, economics, and offshore wind engineering. Professor McGowan is a Fellow of the American Society of Mechanical Engineers (ASME) and editor of Wind Engineering journal. He lives in Northfield, Massachusetts. Anthony Rogers holds both and M.S. and Ph.D. in Mechanical Engineering from the University of Massachusetts and was formerly a senior research engineer in the Renewable Energy Research Laboratory (now the Wind Energy center) there. He is presently a senior engineer at DNV Global Energy Concepts. He has had a long career in the wind energy field, and has been involved with a wide range of topics. These have included wind turbine monitoring and control and the application of remote sensing devices. He lives in Amherst, Massachusetts.

About the Authors ix Preface xi

Acknowledgments xiii

1 Introduction: Modern Wind Energy and its Origins 1

1.1 Modern Wind Turbines 2

1.2 History of Wind Energy 10

References 21

2 Wind Characteristics and Resources 23

2.1 Introduction 23

2.2 General Characteristics of the Wind Resource 24

2.3 Characteristics of the Atmospheric Boundary Layer 36

2.4 Wind Data Analysis and Resource Estimation 53

2.5 Wind Turbine Energy Production Estimates Using

Statistical Techniques 63

2.6 Regional Wind Resource Assessment 65

2.7 Wind Prediction and Forecasting 72

2.8 Wind Measurement and Instrumentation 74

2.9 Advanced Topics 84

References 87

3 Aerodynamics of Wind Turbines 91

3.1 General Overview 91

3.2 One-dimensional Momentum Theory and the Betz Limit 92

3.3 Ideal Horizontal Axis Wind Turbine with Wake Rotation 96

3.4 Airfoils and General Concepts of Aerodynamics 101

3.5 Blade Design for Modern Wind Turbines 115

3.6 Momentum Theory and Blade Element Theory 117

3.7 Blade Shape for Ideal Rotor without Wake Rotation 121

3.8 General Rotor Blade Shape Performance Prediction 124

3.9 Blade Shape for Optimum Rotor with Wake Rotation 131

3.10 Generalized Rotor Design Procedure 133

3.11 Simplified HAWT Rotor Performance Calculation Procedure 138

3.12 Effect of Drag and Blade Number on Optimum Performance 139

3.13 Computational and Aerodynamic Issues in Aerodynamic Design 141

3.14 Aerodynamics of Vertical Axis Wind Turbines 145

References 153

4 Mechanics and Dynamics 157

4.1 Background 157

4.2 Wind Turbine Loads 158

4.3 General Principles of Mechanics 161

4.4 Wind Turbine Rotor Dynamics 172

4.5 Methods for Modeling Wind Turbine Structural Response 200

References 202

5 Electrical Aspects of Wind Turbines 205

5.1 Overview 205

5.2 Basic Concepts of Electrical Power 206

5.3 Power Transformers 217

5.4 Electrical Machines 219

5.5 Power Converters 237

5.6 Electrical Aspects of Variable-Speed Wind Turbines 246

5.7 Ancillary Electrical Equipment 253

References 255

6 Wind Turbine Materials and Components 257

6.1 Overview 257

6.2 Material Fatigue 257

6.3 Wind Turbine Materials 266

6.4 Machine Elements 270

6.5 Principal Wind Turbine Components 276

References 308

7 Wind Turbine Design and Testing 311

7.1 Overview 311

7.2 Design Procedure 312

7.3 Wind Turbine Topologies 316

7.4 Wind Turbine Standards, Technical Specifications, and Certification 322

7.5 Wind Turbine Design Loads 325

7.6 Load Scaling Relations 333

7.7 Power Curve Prediction 336

7.8 Computer Codes for Wind Turbine Design 340

7.9 Design Evaluation 345

7.10 Wind Turbine and Component Testing 346

References 355

8 Wind Turbine Control 359

8.1 Introduction 359

8.2 Overview of Wind Turbine Control Systems 364

8.3 Typical Grid-connected Turbine Operation 370

8.4 Supervisory Control Overview and Implementation 374

8.5 Dynamic Control Theory and Implementation 382

References 404

9 Wind Turbine Siting, System Design, and Integration 407

9.1 General Overview 407

9.2 Wind Turbine Siting 408

9.3 Installation and Operation Issues 416

9.4 Wind Farms 419

9.5 Wind Turbines and Wind Farms in Electrical Grids 433

References 446

10 Wind Energy Applications 449

10.1 General Overview 449

10.2 Distributed Generation 450

10.3 Hybrid Power Systems 450

10.4 Offshore Wind Energy 461

10.5 Operation in Severe Climates 478

10.6 Special Purpose Applications 480

10.7 Energy Storage 489

10.8 Fuel Production 497

References 501

11 Wind Energy System Economics 505

11.1 Introduction 505

11.2 Overview of Economic Assessment of Wind Energy Systems 506

11.3 Capital Costs of Wind Energy Systems 511

11.4 Operation and Maintenance Costs 519

11.5 Value of Wind Energy 521

11.6 Economic Analysis Methods 530

11.7 Wind Energy Market Considerations 539

References 543

12 Wind Energy Systems: Environmental Aspects and Impacts 547

12.1 Introduction 547

12.2 Avian/Bat Interaction with Wind Turbines 549

12.3 Visual Impact of Wind Turbines 556

12.4 Wind Turbine Noise 561

12.5 Electromagnetic Interference Effects 573

12.6 Land-Use Environmental Impacts 582

12.7 Other Environmental Considerations 585

References 589

Appendix A Nomenclature 593

A.1 Note on Nomenclature and Units 593

A.2 Chapter 2 593

A.3 Chapter 3 595

A.4 Chapter 4 597

A.5 Chapter 5 601

A.6 Chapter 6 604

A.7 Chapter 7 606

A.8 Chapter 8 607

A.9 Chapter 9 608

A.10 Chapter 10 610

A.11 Chapter 11 612

A.12 Chapter 12 613

A.13 Abbreviations 614

Appendix B Problems 617

B.1 Problem Solving 617

B.2 Chapter 2 Problems 617

B.3 Chapter 3 Problems 621

B.4 Chapter 4 Problems 628

B.5 Chapter 5 Problems 632

B.6 Chapter 6 Problems 637

B.7 Chapter 7 Problems 639

B.8 Chapter 8 Problems 642

B.9 Chapter 9 Problems 647

B.10 Chapter 10 Problems 652

B.11 Chapter 11 Problems 656

B.12 Chapter 12 Problems 658

Appendix C Data Analysis and Data Synthesis 661

C.1 Overview 661

C.2 Data Analysis 661

C.3 Data Synthesis 671

References 675

Index 677