Related Resources: Electrical Design Engineering

Wind Power Generation and Wind Power Turbine Design

Electrical Electronics Engineering and Design
Engineering Applications and Design
Electric Motors, Generators and Drives
Power Transmission Technology

Wind Power Generation and Wind Power Turbine Design

Premium Membership Required to view Document/Book

Open:

Wind Power Generation and Wind Power Turbine Design

Preface

Along with the fast rising energy demand in the 21st century and the growing recognition of global warming and environmental pollution, energy supply has become an integral and cross-cutting element of economies of many countries. To respond to the climate and energy challenges, more and more countries have prioritized renewable and sustainable energy sources such as wind, solar, hydropower, biomass, geothermal, etc., as the replacements for fossil fuels.

Wind is a clean, inexhaustible, and an environmentally friendly energy source that can provide an alternative to fossil fuels to help improve air quality, reduce greenhouse gases and diversify the global electricity supply. Wind power is the fastest-growing alternative energy segment on a percentage basis with capacity doubling every three years. Today, wind power is flourishing in Europe, North America, and some developing countries such as China and India. In 2009, over 37 GW of new wind capacity were installed all over the world, bringing the total wind capacity to 158 GW. It is believed that wind power will play a more active role as the world moves towards a sustainable energy in the next several decades.

The object of this book is to provide engineers and researchers in the wind power industry, national laboratories, and universities with comprehensive, up-to date, and advanced design techniques and practical approaches. The topics addressed in this book involve the major concerns in wind power generation and wind turbine design. An attempt has been made to include more recent developments in innovative wind technologies, particularly from large wind turbine OEMs. This book is a useful and timely contribution to the wind energy community as a resource for engineers and researchers. It is also suitable to serve as a textbook for a one- or two-semester course at the graduate or undergraduate levels, with the use of all or partial chapters.

To assist readers in developing an appreciation of wind energy and modern wind turbines, this book is organized into four parts. Part 1 consists of five chapters, covering the basics of wind power generation. Chapter 1 provides overviews of the history of wind energy applications, fundamentals of wind energy and basic knowledge of modern wind turbines. Chapter 2 describes how to make wind resource assessment, which is the most important step for determining initial feasibility in a wind project. The assessment may pass through several stages such as initial site identification, detailed site characterizations, site suitability, and energy yield and losses. As a necessary tool for modeling the loads of wind turbines and designing rotor blades, the detail review of aerodynamics, including analytical theories and experiments, are presented in Chapter 3. Chapter 4 provides an overview of the frontline research on structural dynamics of wind turbines, aiming at assessing the integrity and reliability of the complete construction against varying external loading over the targeted lifetime. Chapter 5 discusses the issues related to wind turbine acoustics, which remains one of the challenges facing the wind power industry today.

Part 2 comprises seven chapters, addressing design techniques and developments of various wind turbines. One of the remarkable trends in the wind power industry is that the size and power output from an individual wind turbines have being continuously increasing since 1980s. As the mainstream of the wind power market, multi-megawatts wind turbines today are extensively built in wind farms all over the world. Chapter 6 presents the detail designing methodologies, techniques, and processes of these large wind turbines. While larger wind turbines play a critical role in on-grid wind power generation, small wind turbines are widely used in residential houses, hybrid systems, and other individual remote applications, either on-grid or off-grid, as described in Chapter 7. Chapter 8 summarizes the principles of operation and the historical development of the main types of vertical-axis wind turbines. Due to some significant advantages, vertical-axis turbines will coexists with horizontal-axis turbines for a long time. The innovative turbine techniques are addressed in Chapter 9 for the direct drive superconducting wind generators and in Chapter 10 for the tandem wind rotors. To fully utilize the wind resource on the earth, offshore wind turbine techniques have been remarkably developed since the mid of 1980s. Chapter 11 highlights the challenges for the offshore wind industry, irrespective of geographical locations. To shed new light on small wind turbines, Chapter 12 focuses on updated state-of-the-art technologies, delivering advanced small wind turbines to the global wind market with lower cost and higher reliability.

Part 3 contains five chapters, involving designs and analyses of primary wind turbine components. As one of the most key components in a wind turbine, the rotor blades strongly impact the turbine performance and efficiency. As shown in Chapter 13, the structural design of turbine blades is a complicated process that requires know-how of materials, modeling and testing methods. In Chapter 14, the implementation of the smart rotor concept is addressed, in which the aerodynamics along the blade is controlled and the dynamic loads and modes are dampened. Chapter 15 explains the gear design criteria and offers solutions to the various gear design problems. Chapter 16 involves the design and analysis of wind turbine towers. In pace with the increases in rotor diameter and tower height for large wind turbines, it becomes more important to ensure the serviceability and survivability of towers. For offshore wind turbines, the design of support structures is described in Chapter 17. In this chapter, the extensive overviews of the different foundation types, as well as their fabrications and installations, are provided.

Part 4 includes four chapters, dealing with other important issues in wind power generation. The subject of Chapter 18 is to describe approaches to determine the wind power curves, which are used to estimate the power performing characteristics of wind turbines. Cooling of wind turbines is another challenge for the turbine designers because it strongly impacts on the turbine performance. Various cooling techniques for wind turbines are reviewed and evaluated in Chapter 19. As a complement of Chapter 5, Chapter 20 focuses on engineering approaches in noise measurements and noise abatement methods. In Chapter 21, almost all up-to-the date available wind energy storage techniques are reviewed and analyzed, in view of their applications, costs, advantages, disadvantages, and prospects.

To comprehensively reflect the wind technology developments and the tendencies in wind power generation all over the world, the contributors of the book are engaged in industries, national laboratories and universities at Australia, China, Denmark, Germany, Greece, Ireland, Japan, Sweden, The Netherlands, UK, and USA.

TOC

PART I: BASICS IN WIND POWER GENERATION
CHAPTER 1
Fundamentals of wind energy....................................................................... 3
Wei Tong
1 Wind energy............................................................................................. 3
2 Wind generation ....................................................................................... 4
2.1 Uneven solar heating........................................................................ 4
2.2 Coriolis force.................................................................................... 5
2.3 Local geography............................................................................... 6
3 History of wind energy applications......................................................... 6
3.1 Sailing .............................................................................................. 7
3.2 Wind in metal smelting processes .................................................... 7
3.3 Windmills......................................................................................... 8
3.4 Wind turbines ................................................................................... 8
3.5 Kites ................................................................................................. 8
4 Wind energy characteristics ..................................................................... 9
4.1 Wind power...................................................................................... 9
4.2 Wind characteristics ......................................................................... 12
5 Modern wind turbines .............................................................................. 15
5.1 Wind turbine classification............................................................... 16
5.2 Wind turbine configuration .............................................................. 19
5.3 Wind power parameters ................................................................... 20
5.4 Wind turbine controls....................................................................... 24
6 Challenges in wind power generation ...................................................... 28
6.1 Environmental impacts..................................................................... 28
6.2 Wind turbine noise ........................................................................... 28
6.3 Integration of wind power into grid.................................................. 29
6.4 Thermal management of wind turbines............................................ 30
6.5 Wind energy storage......................................................................... 31
6.6 Wind turbine lifetime ....................................................................... 31
6.7 Cost of electricity from wind power................................................. 32
7 Trends in wind turbine developments and wind power generation .......... 33
7.1 High-power, large-capacity wind turbine......................................... 33
7.2 Offshore wind turbine ...................................................................... 34
7.3 Direct drive wind turbine ................................................................. 35
7.4 High efficient blade.......................................................................... 36
7.5 Floating wind turbine ....................................................................... 37
7.6 Wind turbine with contra-rotating rotors.......................................... 38
7.7 Drivetrain ......................................................................................... 39
7.8 Integration of wind and other energy sources .................................. 40
References................................................................................................ 42
CHAPTER 2
Wind resource and site assessment .............................................................. 49
Wiebke Langreder
1 Initial site identification ........................................................................... 49
2 Wind speed measurements ....................................................................... 50
2.1 Introduction ...................................................................................... 50
2.2 Instruments....................................................................................... 51
2.3 Calibration........................................................................................ 58
2.4 Mounting.......................................................................................... 59
2.5 Measurement period and averaging time ......................................... 60
3 Data analysis ............................................................................................ 61
3.1 Long-term correction........................................................................ 61
3.2 Weibull distribution.......................................................................... 64
4 Spatial extrapolation................................................................................. 66
4.1 Introduction ...................................................................................... 66
4.2 Vertical extrapolation....................................................................... 66
4.3 Flow models ..................................................................................... 70
5 Siting and site suitability .......................................................................... 75
5.1 General ............................................................................................. 75
5.2 Turbulence........................................................................................ 75
5.3 Flow inclination ............................................................................... 79
5.4 Vertical wind speed gradient............................................................ 80
6 Site classification ..................................................................................... 82
6.1 Introduction ...................................................................................... 82
6.2 Extreme winds.................................................................................. 82
7 Energy yield and losses ............................................................................ 84
7.1 Single wind turbine .......................................................................... 84
7.2 Wake and other losses ...................................................................... 84
7.3 Uncertainty....................................................................................... 85
References................................................................................................ 85
CHAPTER 3
Aerodynamics and aeroelastics of wind turbines........................................ 89
Alois P. Schaffarczyk
1 Introduction .............................................................................................. 89
2 Analytical theories ................................................................................... 90
2.1 Blade element theories ..................................................................... 98
2.2 Optimum blade shape....................................................................... 100
3 Numerical CFD methods applied to wind turbine flow............................ 101
4 Experiments.............................................................................................. 103
4.1 Field rotor aerodynamics.................................................................. 103
4.2 Chinese-Swedish wind tunnel investigations ................................... 104
4.3 NREL unsteady aerodynamic experiments in the NASA
AMES-wind tunnel .......................................................................... 104
4.4 MEXICO.......................................................................................... 105
5 Aeroelastics .............................................................................................. 105
5.1 Generalities ...................................................................................... 105
5.2 Tasks of aeroelasticity...................................................................... 106
5.3 Instructive example: the Baltic Thunder .......................................... 107
6 Impact on commercial systems ................................................................ 107
6.1 Small wind turbines.......................................................................... 107
6.2 Main-stream wind turbines............................................................... 109
6.3 Multi MW turbines........................................................................... 110
7 Non-standard wind turbines ..................................................................... 111
7.1 Vertical axis wind turbines............................................................... 111
7.2 Diffuser systems............................................................................... 114
8 Summary and outlook .............................................................................. 115
References................................................................................................ 116
CHAPTER 4
Structural dynamics of wind turbines.......................................................... 121
Spyros G. Voutsinas
1 Wind turbines from a structural stand point ............................................. 121
2 Formulation of the dynamic equations..................................................... 123
3 Beam theory and FEM approximations.................................................... 124
3.1 Basic assumptions and equation derivation...................................... 124
3.2 Principle of virtual work and FE approximations ............................ 127
4 Multi-component systems ........................................................................ 129
4.1 Reformulation of the dynamic equations ......................................... 129
4.2 Connection conditions...................................................................... 131
4.3 Implementation issues ...................................................................... 132
4.4 Eigenvalue analysis and linear stability ........................................... 133
5 Aeroelastic coupling................................................................................. 135
6 Rotor stability analysis ............................................................................. 137
7 More advanced modeling issues............................................................... 139
7.1 Timoshenko beam model ................................................................. 139
7.2 Second order beam models .............................................................. 140
CHAPTER 8
Development and analysis of vertical-axis wind turbines .......................... 277
Paul Cooper
1 Introduction.............................................................................................. 277
2 Historical development of VAWTs.......................................................... 278
2.1 Early VAWT designs ....................................................................... 278
2.2 VAWT types .................................................................................... 279
2.3 VAWTs in marine current applications............................................ 289
3 Analysis of VAWT performance ............................................................. 289
3.1 Double-multiple-stream tube analysis.............................................. 290
3.2 Other methods of VAWT analysis ................................................... 298
4 Summary .................................................................................................. 299
References................................................................................................ 299
CHAPTER 9
Direct drive superconducting wind generators ........................................... 303
Clive Lewis
1 Introduction.............................................................................................. 303
2 Wind turbine technology.......................................................................... 304
2.1 Wind turbine market......................................................................... 304
2.2 Case for direct drive ......................................................................... 305
2.3 Direct drive generators ..................................................................... 306
3 Superconducting rotating machines ......................................................... 308
3.1 Superconductivity ............................................................................ 308
3.2 High temperature superconductors................................................... 309
3.3 HTS rotating machines..................................................................... 310
4 HTS technology in wind turbines............................................................. 310
4.1 Benefits of HTS generator technology............................................. 310
4.2 Commercial exploitation of HTS wind generators........................... 312
5 Developments in HTS wires..................................................................... 313
5.1 1G HTS wire technology.................................................................. 313
5.2 2G HTS wire technology.................................................................. 314
5.3 HTS wire cost trends ........................................................................ 315
6 Converteam HTS wind generator............................................................. 315
6.1 Generator specification .................................................................... 316
6.2 Project aims...................................................................................... 316
6.3 Conceptual design ............................................................................ 316
6.4 Design challenges............................................................................. 320
6.5 The cost-benefit study ...................................................................... 325
6.6 Model generator ............................................................................... 326
6.7 Material testing and component prototypes ..................................... 326
6.8 The full scale detailed design ........................................................... 327
3 The product design process ...................................................................... 196
3.1 Establishing the need........................................................................ 197
3.2 The business case ............................................................................. 197
3.3 Tollgates........................................................................................... 197
3.4 Structuring the team ......................................................................... 199
3.5 Product requirements and product specification .............................. 199
3.6 Launching the product...................................................................... 200
3.7 Design definition: conceptual → preliminary → detailed................ 200
3.8 Continual cycles of re-focus; systems–components–systems .......... 205
4 MW WT design techniques...................................................................... 206
4.1 Requirements.................................................................................... 206
4.2 Systems ............................................................................................ 208
4.3 Components...................................................................................... 215
4.4 Mechanical ....................................................................................... 219
4.5 Electrical .......................................................................................... 236
4.6 Controls............................................................................................ 240
4.7 Siting ................................................................................................ 244
5 Special considerations in MW WT design ............................................... 247
5.1 Continuously circling back to value engineering ............................. 247
5.2 Intellectual property (IP) .................................................................. 249
5.3 Permitting and perceptions............................................................... 249
5.4 Codes and standards......................................................................... 250
5.5 Third party certification ................................................................... 250
5.6 Markets, finance structures and policy............................................. 250
6 MW WT development techniques............................................................ 250
6.1 Validation background ..................................................................... 251
6.2 Product validation techniques .......................................................... 251
7 Closure ..................................................................................................... 252
References................................................................................................ 253
CHAPTER 7
Design and development of small wind turbines......................................... 257
Lawrence Staudt
1 Small wind technology............................................................................. 257
1.1 Small wind system configurations ................................................... 260
1.2 Small wind turbine rotor design ....................................................... 262
1.3 System design................................................................................... 267
1.4 Tower design.................................................................................... 273
2 Future developments ................................................................................ 274
3 Conclusions.............................................................................................. 275
References................................................................................................ 276
CHAPTER 8
Development and analysis of vertical-axis wind turbines .......................... 277
Paul Cooper
1 Introduction.............................................................................................. 277
2 Historical development of VAWTs.......................................................... 278
2.1 Early VAWT designs ....................................................................... 278
2.2 VAWT types .................................................................................... 279
2.3 VAWTs in marine current applications............................................ 289
3 Analysis of VAWT performance ............................................................. 289
3.1 Double-multiple-stream tube analysis.............................................. 290
3.2 Other methods of VAWT analysis ................................................... 298
4 Summary .................................................................................................. 299
References................................................................................................ 299
CHAPTER 9
Direct drive superconducting wind generators ........................................... 303
Clive Lewis
1 Introduction.............................................................................................. 303
2 Wind turbine technology.......................................................................... 304
2.1 Wind turbine market......................................................................... 304
2.2 Case for direct drive ......................................................................... 305
2.3 Direct drive generators ..................................................................... 306
3 Superconducting rotating machines ......................................................... 308
3.1 Superconductivity ............................................................................ 308
3.2 High temperature superconductors................................................... 309
3.3 HTS rotating machines..................................................................... 310
4 HTS technology in wind turbines............................................................. 310
4.1 Benefits of HTS generator technology............................................. 310
4.2 Commercial exploitation of HTS wind generators........................... 312
5 Developments in HTS wires..................................................................... 313
5.1 1G HTS wire technology.................................................................. 313
5.2 2G HTS wire technology.................................................................. 314
5.3 HTS wire cost trends ........................................................................ 315
6 Converteam HTS wind generator............................................................. 315
6.1 Generator specification .................................................................... 316
6.2 Project aims...................................................................................... 316
6.3 Conceptual design ............................................................................ 316
6.4 Design challenges............................................................................. 320
6.5 The cost-benefit study ...................................................................... 325
6.6 Model generator ............................................................................... 326
6.7 Material testing and component prototypes ..................................... 326
6.8 The full scale detailed design ........................................................... 327
7 The way forward ...................................................................................... 327
8 Other HTS wind generator projects.......................................................... 328
9 Conclusions.............................................................................................. 328
References................................................................................................ 328
CHAPTER 10
Intelligent wind power unit with tandem wind rotors................................ 333
Toshiaki Kanemoto & Koichi Kubo
1 Introduction.............................................................................................. 333
2 Previous works on tandem wind rotors .................................................... 334
3 Superior operation of intelligent wind power unit.................................... 337
4 Preparation of double rotational armature type generator ........................ 339
4.1 Double-fed induction generator with double rotational armatures... 339
4.2 Synchronous generator with double rotational armatures ................ 342
5 Demonstration of intelligent wind power unit.......................................... 345
5.1 Preparation of the tentative tandem wind rotors............................... 345
5.2 Preparation of the model unit and operations on the vehicle............ 349
5.3 Performances of the tandem wind rotors.......................................... 350
5.4 Trial of the reasonable operation...................................................... 352
6 Optimizing the profiles of tandem wind rotors ........................................ 353
6.1 Experiments in the wind tunnel........................................................ 353
6.2 Optimum diameter ratio of front and rear wind rotors ..................... 354
6.3 Optimum axial distance between front and rear wind rotors............ 357
6.4 Characteristics of the tandem wind rotors ........................................ 358
7 Conclusion................................................................................................ 359
References................................................................................................ 360
CHAPTER 11
Offshore wind turbine design ....................................................................... 363
Danian Zheng & Sumit Bose
1 Introduction.............................................................................................. 363
2 Offshore resource potential ...................................................................... 364
3 Current technology trends ........................................................................ 365
4 Offshore-specific design challenges......................................................... 366
4.1 Economic challenges........................................................................ 366
4.2 25-m barrier challenge ..................................................................... 367
4.3 Overcoming the 25-m barrier ........................................................... 368
4.4 Design envelope challenge............................................................... 369
4.5 Corrosion, installation and O&M challenges ................................... 375
4.6 Environmental footprint ................................................................... 375
5 Subcomponent design .............................................................................. 376
5.1 Low cost foundation concepts.......................................................... 376
5.2 Rotor design for offshore wind turbines........................................... 383
5.3 Offshore control, monitoring, diagnostics and repair systems ......... 384
5.4 Drivetrain and electrical system....................................................... 385
6 Other noteworthy innovations and improvements in technology............. 386
6.1 Assembly-line procedures ................................................................ 386
6.2 System design of rotor with drivetrain ............................................. 386
6.3 Service model................................................................................... 387
7 Conclusion................................................................................................ 387
References................................................................................................ 387
CHAPTER 12
New small turbine technologies .................................................................... 389
Hikaru Matsumiya
1 Introduction.............................................................................................. 389
1.1 Definition of SWT............................................................................ 390
1.2 Low Reynolds number problem....................................................... 391
2 Other technical problems particular with SWTs ...................................... 393
3 Purposes of use of SWTs ......................................................................... 394
4 Wind conditions ....................................................................................... 395
4.1 External conditions........................................................................... 395
4.2 Normal wind conditions and external wind conditions .................... 396
4.3 Models of wind characteristics......................................................... 396
5 Design of SWTs ....................................................................................... 396
5.1 Conceptual design ............................................................................ 396
5.2 Aerodynamic design......................................................................... 397
5.3 Selection of aerofoil sections ........................................................... 400
5.4 Structural design............................................................................... 401
6 Control strategy of SWTs......................................................................... 401
7 Yaw control.............................................................................................. 403
7.1 Tail wing .......................................................................................... 403
7.2 Passive yaw control with downwind system .................................... 405
8 Power/speed control ................................................................................. 405
8.1 Initial start-up control....................................................................... 405
8.2 Power/speed control ......................................................................... 406
9 Tests and verification ............................................................................... 407
9.1 Safety requirements.......................................................................... 407
9.2 Laboratory and field tests of a new rotor.......................................... 407
10 Captureability........................................................................................... 411
References................................................................................................ 413
PART III: DESIGN OF WIND TURBINE COMPONENTS
CHAPTER 13
Blade materials, testing methods and structural design............................. 417
Bent F. Sørensen, John W. Holmes, Povl Brøndsted & Kim Branner
1 Introduction.............................................................................................. 417
2 Blade manufacture.................................................................................... 418
2.1 Loads on wind turbine rotor blades.................................................. 418
2.2 Blade construction............................................................................ 419
2.3 Materials........................................................................................... 421
2.4 Processing methods.......................................................................... 423
3 Testing of wind turbine blades ................................................................. 423
3.1 Purpose............................................................................................. 423
3.2 Certification tests (static and cyclic) ................................................ 424
3.3 Examples of full-scale tests used to determine deformation
and failure modes ............................................................................. 425
4 Failure modes of wind turbine blades ...................................................... 425
4.1 Definition of blade failure modes..................................................... 425
4.2 Identified blade failure modes.......................................................... 426
5 Material properties ................................................................................... 428
5.1 Elastic properties.............................................................................. 428
5.2 Strength and fracture toughness properties ...................................... 429
6 Materials testing methods......................................................................... 431
6.1 Test methods for strength determination.......................................... 431
6.2 Test methods for determination of fracture mechanics properties ... 432
6.3 Failure under cyclic loads ................................................................ 435
7 Modeling of wind turbine blades.............................................................. 439
7.1 Modeling of structural behavior of wind turbine blades .................. 439
7.2 Models of specific failure modes ..................................................... 444
7.3 Examples of sub-components with damage ..................................... 450
7.4 Full wind turbine blade models with damage................................... 457
8 Perspectives and concluding remarks....................................................... 459
References................................................................................................ 460
CHAPTER 14
Implementation of the ‘smart’ rotor concept.............................................. 467
Anton W. Hulskamp & Harald E.N. Bersee
1 Introduction.............................................................................................. 467
1.1 Current load control on wind turbines.............................................. 468
1.2 The ‘smart’ rotor concept................................................................. 470
2 Adaptive wings and rotor blades .............................................................. 471
2.1 Adaptive aerofoils and smart wings ................................................. 471
2.2 Smart helicopter rotor blades ........................................................... 475
3 Adaptive materials.................................................................................... 477
3.1 Piezoelectrics.................................................................................... 477
3.2 Shape memory alloys ....................................................................... 482
4 Structural layout of smart rotor blades ..................................................... 492
5 Control and dynamics............................................................................... 493
5.1 Load alleviation experiments ........................................................... 494
5.2 Control ............................................................................................. 494
5.3 Results and discussion...................................................................... 497
5.4 Rotating experiments........................................................................ 498
6 Conclusions and discussion...................................................................... 500
6.1 Conclusions on adaptive aerospace structures.................................. 500
6.2 Conclusions on adaptive materials ................................................... 500
6.3 Conclusions for wind turbine blades ................................................ 500
6.4 Control issues ................................................................................... 501
References................................................................................................ 501
CHAPTER 15
Optimized gearbox design............................................................................. 509
Ray Hicks
1 Introduction.............................................................................................. 509
2 Basic gear tooth design ............................................................................ 510
3 Geartrains ................................................................................................. 515
4 Bearings ................................................................................................... 520
5 Gear arrangements.................................................................................... 521
6 Torque limitation...................................................................................... 523
7 Conclusions.............................................................................................. 524
CHAPTER 16
Tower design and analysis ............................................................................ 527
Biswajit Basu
1 Introduction.............................................................................................. 527
2 Analysis of towers.................................................................................... 529
2.1 Tower blade coupling....................................................................... 529
2.2 Rotating blades................................................................................. 530
2.3 Forced vibration analysis ................................................................. 531
2.4 Rotationally sampled spectra............................................................ 532
2.5 Loading on tower-nacelle................................................................. 533
2.6 Response of tower including blade–tower interaction ..................... 534
3 Design of tower ........................................................................................ 537
3.1 Gust factor approach ........................................................................ 538
3.2 Displacement GRF ........................................................................... 538
3.3 Bending moment GRF ..................................................................... 540
4 Vibration control of tower........................................................................ 542
4.1 Response of tower with a TMD ....................................................... 542
4.2 Design of TMD ................................................................................ 543
6 Offshore towers........................................................................................ 547
6.1 Simple model for offshore towers .................................................... 548
6.2 Wave loading ................................................................................... 549
6.3 Joint distribution of wind and waves................................................ 550
6.4 Vibration control of offshore towers ................................................ 551
7 Conclusions.............................................................................................. 552
References................................................................................................ 553
CHAPTER 17
Design of support structures for offshore wind turbines ........................... 559
J. van der Tempel, N.F.B. Diepeveen, D.J. Cerda Salzmann & W.E. de Vries
1 Introduction.............................................................................................. 559
2 History of offshore, wind and offshore wind development
of offshore structures ............................................................................... 560
2.1 The origin of “integrated design” in offshore wind energy.............. 560
2.2 From theory to practice: Horns Rev ................................................. 563
2.3 Theory behind practice..................................................................... 564
3 Support structure concepts ....................................................................... 566
3.1 Basic functions ................................................................................. 566
3.2 Foundation types .............................................................................. 567
4 Environmental loads................................................................................. 571
4.1 Waves............................................................................................... 571
4.2 Currents............................................................................................ 574
4.3 Wind................................................................................................. 575
4.4 Soil ................................................................................................... 577
5 Support structure design........................................................................... 578
5.1 Design steps ..................................................................................... 578
5.2 Turbine characteristics ..................................................................... 580
5.3 Natural frequency check................................................................... 581
5.4 Extreme load cases........................................................................... 583
5.5 Foundation design ............................................................................ 583
5.6 Buckling & shear check ................................................................... 584
5.7 Fatigue check ................................................................................... 584
5.8 Optimizing........................................................................................ 587
6 Design considerations .............................................................................. 587
6.1 Offshore access ................................................................................ 587
6.2 Offshore wind farm aspects.............................................................. 589
References................................................................................................ 591
PART IV: IMPORTANT ISSUES IN WIND TURBINE DESIGN
CHAPTER 18
Power curves for wind turbines.................................................................... 595
Patrick Milan, Matthias Wächter, Stephan Barth & Joachim Peinke
1 Introduction.............................................................................................. 595
2 Power performance of wind turbines ....................................................... 596
2.1 Introduction to power performance.................................................. 596
2.2 Theoretical considerations................................................................ 596
2.3 Standard power curves ..................................................................... 600
2.4 Dynamical or Langevin power curve ............................................... 603
3 Perspectives.............................................................................................. 607
3.1 Characterizing wind turbines............................................................ 607
3.2 Monitoring wind turbines................................................................. 609
3.3 Power modeling and prediction........................................................ 609
4 Conclusions.............................................................................................. 610
References................................................................................................ 611
CHAPTER 19
Wind turbine cooling technologies ............................................................... 613
Yanlong Jiang
1 Operating principle and structure of wind turbines .................................. 613
2 Heat dissipating components and analysis ............................................... 614
2.1 Gearbox............................................................................................ 615
2.2 Generator.......................................................................................... 616
2.3 Control system ................................................................................. 616
3 Current wind turbine cooling systems...................................................... 617
3.1 Forced air cooling system ................................................................ 617
3.2 Liquid cooling system ...................................................................... 619
4 Design and optimization of a cooling system........................................... 622
4.1 Design of the liquid cooling system ................................................. 622
4.2 Optimization of the liquid cooling system ....................................... 625
5 Future prospects on new type cooling system.......................................... 631
5.1 Vapor-cycle cooling methods .......................................................... 631
5.2 Centralized cooling method ............................................................. 632
5.3 Jet cooling system with solar power assistance ............................... 634
5.4 Heat pipe cooling gearbox ............................................................... 637
References ..................................................................................................... 639
CHAPTER 20
Wind turbine noise measurements and abatement methods ..................... 641
Panagiota Pantazopoulou
1 Introduction.............................................................................................. 641
2 Noise types and patterns........................................................................... 643
2.1 Sources of wind turbine sound ......................................................... 643
2.2 Infrasound ........................................................................................ 644
2.3 Mechanical generation of sound....................................................... 645
3 Sound level............................................................................................... 648
4 Factors that affect wind turbine noise propagation .................................. 650
4.1 Source characteristics....................................................................... 650
4.2 Air absorption................................................................................... 650
4.3 Ground absorption............................................................................ 651
4.4 Land topology .................................................................................. 651
4.5 Weather effects, wind and temperature gradients ............................ 652
5 Measurement techniques and challenges.................................................. 652
5.1 For small wind turbines.................................................................... 653
6 Abatement methods.................................................................................. 654
7 Noise standards ........................................................................................ 657
8 Present and future..................................................................................... 657
References................................................................................................ 658
CHAPTER 21
Wind energy storage technologies ................................................................ 661
Martin Leahy, David Connolly & Noel Buckley
1 Introduction.............................................................................................. 661
2 Parameters of an energy storage device ................................................... 662
3 Energy storage plant components............................................................. 663
3.1 Storage medium ............................................................................... 663
3.2 Power conversion system ................................................................. 663
3.3 Balance of plant................................................................................ 664
4 Energy storage technologies..................................................................... 664
4.1 Pumped-hydroelectric energy storage .............................................. 665
4.2 Underground pumped-hydroelectric energy storage ........................ 668
4.3 Compressed air energy storage......................................................... 670
4.4 Battery energy storage...................................................................... 672
4.5 Flow battery energy storage ............................................................. 678
4.6 Flywheel energy storage................................................................... 683
4.7 Supercapacitor energy storage.......................................................... 685
4.8 Superconducting magnetic energy storage....................................... 687
4.9 Hydrogen energy storage system ..................................................... 689
4.10 Thermal energy storage.................................................................... 694
4.11 Electric vehicles ............................................................................... 697
5 Energy storage applications...................................................................... 699
5.1 Load management ............................................................................ 699
5.2 Spinning reserve............................................................................... 700
5.3 Transmission and distribution stabilization...................................... 700
5.4 Transmission upgrade deferral ......................................................... 700
5.5 Peak generation ................................................................................ 700
5.6 Renewable energy integration.......................................................... 701
5.7 End-use applications ........................................................................ 701
5.8 Emergency backup ........................................................................... 701
5.9 Demand side management................................................................ 701
6 Comparison of energy storage technologies............................................. 702
6.1 Large power and energy capacities .................................................. 702
6.2 Medium power and energy capacities .............................................. 703
6.3 Large power or storage capacities .................................................... 703
6.4 Overall comparison of energy storage technologies......................... 703
6.5 Energy storage systems .................................................................... 703
7 Energy storage in Ireland and Denmark................................................... 706
8 Conclusions.............................................................................................. 711
References................................................................................................ 712
Index 715