| Preface | 5 |
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| Contents | 6 |
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| List of Figures | 9 |
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| List of Tables | 11 |
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| About the Authors | 12 |
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| 1 Wind Energy Today | 13 |
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| 1.1 Status | 13 |
| 1.2 Advantages and Disadvantages of Wind Energy Systems | 14 |
| 1.2.1 Advantages | 15 |
| 1.2.2 Disadvantages | 15 |
| 1.3 Different Types of Wind Energy Converters: An Overview | 15 |
| 2 Wind: Origin and Local Effects | 19 |
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| 2.1 Origin and Global Availability | 19 |
| 2.2 Local Effects on Wind Flow | 19 |
| 2.3 Attractive Locations for Wind Energy | 21 |
| 2.4 Local Effects on Wind Flow | 22 |
| 2.4.1 Roughness Length and Wind Shear | 22 |
| 2.4.2 Wind Speed Variability | 22 |
| 2.4.3 Turbulence | 23 |
| 2.4.4 Obstacles to Wind Flow | 24 |
| 2.4.5 The Wind Wake and Park Effect | 25 |
| 2.4.6 The Hill Effect and Tunnel Effect | 25 |
| 2.5 Selecting a Turbine Site | 26 |
| 3 Physics of Wind Energy | 28 |
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| 3.1 Energy Content in Wind | 28 |
| 3.2 Energy Conversion at the Blade | 30 |
| 3.3 Power Coefficients and Principles of Design | 32 |
| 3.3.1 Coefficient of Power c p and Betz' Law | 32 |
| 3.3.2 Tip Speed Ratio | 33 |
| 3.3.3 Power Efficiency | 33 |
| 3.3.4 Principles of Design | 35 |
| 3.4 Wind Variations | 35 |
| 3.4.1 Wind Shear with Height | 35 |
| 3.4.2 Influence of Weibull Distribution | 37 |
| 4 Components of a Wind Energy Converter | 40 |
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| 4.1 Rotor Blades | 40 |
| 4.2 Gearboxes | 42 |
| 4.3 Generators | 43 |
| 4.3.1 Generating Voltage generating voltage | 43 |
| 4.3.2 Generator Cooling System | 43 |
| 4.3.3 Generator Rotational Speed | 43 |
| 4.3.4 Two Speed, Pole Changing Generators | 45 |
| 4.4 Towers | 45 |
| 4.5 Miscellaneous Components | 46 |
| 5 Design Considerations | 51 |
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| 5.1 Rotor Area of Turbines | 51 |
| 5.1.1 Reasons for Choosing Large Turbines | 51 |
| 5.1.2 Reasons for Choosing Smaller Turbines | 51 |
| 5.2 Number of Blades | 52 |
| 5.3 Horizontal or Vertical Axis Turbine | 53 |
| 5.4 Upwind upwind or Downwind Turbine | 55 |
| 5.5 Load Considerations for Turbine Selection | 56 |
| 5.6 Wind Turbines: With or Without Gearbox | 57 |
| 5.7 Requirement of Grid, Synchronous or Asynchronous Generators | 59 |
| 5.8 Issue of Noise and Its Control | 63 |
| 6 Operation and Control of Wind Energy Converters | 66 |
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| 6.1 Power Curve and Capacity Factor | 66 |
| 6.1.1 Power Curve | 66 |
| 6.1.2 Capacity Factor | 67 |
| 6.2 Power Control of Wind Turbines | 68 |
| 6.2.1 Pitch Control | 69 |
| 6.2.1.1 Running a Pitch Controlled Turbine at Variable Speed | 70 |
| 6.2.2 Stall Control | 71 |
| 6.2.2.1 Passive Stall Control | 71 |
| 6.2.2.2 Active Stall Control | 72 |
| 6.2.3 The Yaw Control | 72 |
| 6.3 Connection to the Grid | 73 |
| 6.3.1 Applications of Wind Energy Converters | 73 |
| 6.3.2 Voltage Requirement | 74 |
| 6.3.3 Special Aspects of the Connection of Offshore Wind Parks | 74 |
| 7 Economics and Policy Issues | 77 |
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| 7.1 Cost of Wind Turbines cost of wind turbine | 77 |
| 7.1.1 Initial Cost of Wind Turbine | 77 |
| 7.1.2 Operation and Maintenance Costs for Wind Turbines | 78 |
| 7.1.2.1 Operation Maintenance Costs | 78 |
| 7.1.2.2 Turbine Reinvestment (Refurbishment, Major Overhauls) | 78 |
| 7.1.2.3 The Availability Factor availability factor | 79 |
| 7.2 Electrical Tariffs | 79 |
| 7.3 Mechanisms to Support Funding | 81 |
| 7.3.1 Capacity Credit | 81 |
| 7.3.2 Environmental Credit environmental credit and Clear Development Mechanism | 82 |
| 7.3.3 Tax Benefits tax benefit | 82 |
| 7.4 Wind Energy Economics | 82 |
| 7.4.1 Financial Analysis -- A Case Study for India | 83 |
| 7.4.2 Financing financing of a Wind Park -- A Case in Germany | 83 |
| 7.5 Wind Turbines After Operational Life | 85 |
| 8 Outlook | 86 |
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| Glossary | 87 |
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| Literature | 88 |
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| Index | 89 |