UTRECHT UNIVERSITY Master Thesis The Technical and Economic Potential of Airborne Wind Energy Heilmann Jannis 8/30/2012 STUDENT: JANNIS HEILMANN CONTACT: [email protected] STUDENT NUMBER: 3558657 COURSE NAME: RESEARCH PROJECT ENERGY SCIENCE DEPARTMENT: DEPT. OF SCIENCE, TECHNOLOGY AND SOCIETY SUPERVISOR (UU): DR. WILFRIED VAN SARK SUPERVISORS (FHNW): COREY HOULE, PROF. DR. HEINZ BURTSCHER SUPERVISOR (ALSTOM AG) DR. GIANFRANCO GUIDATI CONTENTS Abstract .................................................................................................................................................................................. 1 Preface .................................................................................................................................................................................... 2 1 Introduction ................................................................................................................................................................ 3 1.1 Why wind energy? .......................................................................................................................................... 3 1.2 Potential for Innovation ............................................................................................................................... 7 1.3 Airborne Wind Energy – The Major Variants ...................................................................................... 9 1.3.1 Airborne Wind Turbine ................................................................................................................... 11 1.3.2 Pumping Kite Generator .................................................................................................................. 12 1.4 Airborne versus Conventional Wind Energy .................................................................................... 13 1.4.1 Tower versus Tether ........................................................................................................................ 13 1.4.2 Kite Versus Rotor Blade................................................................................................................... 14 1.5 Assessing a Technology’s Potential ...................................................................................................... 14 1.6 Research Questions ..................................................................................................................................... 16 1.7 Limitations ...................................................................................................................................................... 16 2 Background .............................................................................................................................................................. 18 2.1 Wind Resource Fundamentals ............................................................................................................... 18 2.1.1 Wind Speed Distribution ................................................................................................................. 18 2.1.2 Wind Shear............................................................................................................................................ 19 2.1.3 Temporal Variations ......................................................................................................................... 20 2.2 Aerodynamics Fundamentals ................................................................................................................. 21 2.3 Efficiency Considerations ......................................................................................................................... 21 2.3.1 Material Efficiency ............................................................................................................................. 22 2.4 Cost of Energy Analysis ............................................................................................................................. 24 2.5 Electricity Market and Feed-in Tariffs ................................................................................................ 24 2.6 Key References.............................................................................................................................................. 25 3 Methodology ............................................................................................................................................................ 30 3.1 System Design ............................................................................................................................................... 30 3.1.1 Assumptions ......................................................................................................................................... 31 3.1.2 Machine Design ................................................................................................................................... 31 3.1.3 Kite Scenarios ...................................................................................................................................... 32 3.2 Performance Simulation Development .............................................................................................. 34 3.2.1 Performance model ........................................................................................................................... 34 3.2.2 Implementation .................................................................................................................................. 36 3.2.3 Output ..................................................................................................................................................... 36 3.3 Cost Analysis .................................................................................................................................................. 37 3.3.1 Uncertainty ........................................................................................................................................... 38 3.3.2 Cost Model ............................................................................................................................................. 38 3.3.3 Currency................................................................................................................................................. 41 3.3.4 Fixed Charge Rate .............................................................................................................................. 42 3.3.5 Revenues ................................................................................................................................................ 42 3.4 Wind Modelling and Annual Energy Production ............................................................................ 44 3.4.1 Wind Data .............................................................................................................................................. 44 3.4.2 Calculation Methods.......................................................................................................................... 44 3.4.3 Output ..................................................................................................................................................... 45 4 Parameter Study Results .................................................................................................................................... 47 4.1 Design Parameter Study ........................................................................................................................... 47 4.1.1 Projected Kite Area ............................................................................................................................ 47 4.1.2 Nominal Generator Power .............................................................................................................. 49 4.1.3 Nominal Tether Force (Scaling) ................................................................................................... 51 4.1.4 Optimal Design .................................................................................................................................... 53 4.2 Operational Parameter Study ................................................................................................................. 53 4.2.1 Tether angle.......................................................................................................................................... 53 4.3 Current Kite Scenario ................................................................................................................................. 54 4.4 Gearbox Option ............................................................................................................................................. 57 4.5 Secondary Parameters Sensitivity ........................................................................................................ 58 5 Comparison to Conventional Turbine ........................................................................................................... 61 6 Wind Modeling Results ....................................................................................................................................... 65 6.1 Wind Shear Exponent ................................................................................................................................ 65 6.2 Mean Wind Speed .......................................................................................................................................