Preface page ................................................. xiii
Acknowledgements .............................................. xiv
1 Wind power and our energy needs: an overview ................. 1
Traditional windmills ........................................ 1
Power and energy in the modern world ......................... 2
Global warming and climate change ............................ 3
Renewable energy sources ..................................... 6
Wind energy conversion ....................................... 7
Energy payback and wind energy costs ...................... 8
Intermittency issues ...................................... 9
Wind or nuclear? .......................................... 9
Costs compared with conventional generation .............. 10
Wind power's growth and potential ........................... 11
2 The first windmills ......................................... 15
Hero's toy windmill ......................................... 15
Early Persian drag-driven windmills ......................... 15
Chinese drag-driven windmills ............................... 19
The European windmill ....................................... 20
How post mills work ...................................... 21
Origins and economics .................................... 22
3 Seven centuries of service .................................. 27
Post mills .................................................. 27
Diffusion through Europe ................................. 27
Medieval milling capacity ................................ 28
Controlling the mill ..................................... 29
Sail developments ........................................ 30
Milling the grain ........................................ 33
Design evolution ......................................... 35
Smock mills and tower mills ................................. 37
Control refinements ...................................... 40
The power output from traditional windmills ................. 41
Land drainage and other applications ........................ 46
The windmill's nineteenth-century peak ...................... 47
Causes of decline ........................................... 48
Steam power .............................................. 48
White bread .............................................. 49
Roller mills ............................................. 51
The American multi-bladed windpump .......................... 52
4 Generating electricity: the experimental years, 1887 to
1973 ........................................................ 57
The first wind-powered electricity generation ............... 58
Danish beginnings: Poul la Cour ............................. 63
The inter-war years ......................................... 65
Small wind-electric systems ................................. 68
Grandpa's Knob, Vermont: the first megawatt-plus machine .... 70
Wartime shortages rekindle Danish interest .................. 73
Post-war energy concerns, and Denmark's Gedser mill ......... 75
French and German post-war programmes ....................... 79
The UK post-war programme ................................... 81
5 The evolution of the modern wind turbine, 1973 to 1990 ...... 87
The 1973 oil crisis ......................................... 87
The American Federal wind power program ..................... 89
First generation machines, Mod-0 and Mod-1 ............... 89
Second- and third-generation machines, Mod-2 and
Mod-5 .................................................... 92
The American/Swedish WTS-4 ............................... 94
The Darrieus vertical-axis wind turbine .................. 95
European national wind power programmes ..................... 99
Sweden ................................................... 99
Germany ................................................. 101
Denmark ................................................. 102
A different Danish way forward ............................. 105
The Tvind machine ....................................... 105
Small grid-connected wind turbines ...................... 106
The Californian wind boom .................................. 112
The first wind farms .................................... 113
Danish imports .......................................... 115
The market peaks ........................................ 118
Environmental concerns .................................. 119
Design evolution ........................................ 120
Danish success factors ..................................... 123
6 Progress and economics in Europe, 1973 to 1990 ............. 125
Denmark .................................................... 125
Stall control or pitch control? ......................... 126
Shut-down in high wind speeds ........................... 128
Costs relative to the annual energy output .............. 129
Costs per unit energy output ............................ 131
Cost comparisons ........................................ 132
The Netherlands and Germany ................................ 133
7 UK progress, 1973 to 1990 .................................. 137
Wind power: the least promising renewables option? ......... 137
The offshore wind potential ................................ 138
Managing wind power's variability .......................... 140
The Department of Energy wind programme .................... 142
The Orkney multi-megawatt wind turbine .................. 142
Offshore wind farm assessment ........................... 143
Vertical-axis wind turbines ............................. 145
Other UK wind turbine developments ......................... 149
Lawson-Tancred .......................................... 149
Fair Isle ............................................... 150
Carmarthen Bay wind turbine test centre ................. 151
Howden .................................................. 151
Wind Energy Group ....................................... 153
Institutional barriers ..................................... 153
Privatisation and the Non-Fossil Fuel Obligation (NFFO) .... 155
8 Development and deployment, 1990 to 2008 ................... 159
Global overview ............................................ 159
Denmark .................................................... 162
The 1990s, a decade of growth ........................... 162
Offshore wind makes progress ............................ 165
Danish overview ......................................... 169
Germany .................................................... 171
1991: a feed-in tariff established ...................... 171
Domestic manufacture .................................... 172
From 2000: the Renewable Energy Law ..................... 174
German overview ......................................... 176
Spain ...................................................... 178
The 1994 feed - in tariff ............................... 178
Spanish overview ........................................ 180
United Kingdom ............................................. 181
The disappointing 1990s ................................. 181
Why NFFO failed ......................................... 185
The Renewables Obligation ............................... 187
Offshore wind farms ..................................... 189
UK overview ............................................. 193
United States .............................................. 194
Low growth beginnings ................................... 194
The Production Tax Credit (PTC) and 'green power' ....... 195
Momentum builds ......................................... 197
US overview ............................................. 199
Canada, Netherlands and Japan .............................. 202
India ...................................................... 203
China ...................................................... 205
The future: from marginal to mainstream .................... 209
Low-carbon options for electricity generation .............. 210
Carbon capture and storage .............................. 210
Nuclear power ........................................... 211
Renewables .............................................. 212
Wind power's progress ...................................... 214
Cost-of-energy comparisons ................................. 216
Variability: keeping the lights on ......................... 219
Wind power's global growth ................................. 221
Appendix A The power output from wind turbines ............ 227
The Betz limit .......................................... 229
How many blades? The effect of solidity ................. 229
Efficiency .............................................. 231
Rotor drag .............................................. 231
Appendix В The performance of traditional windmills ....... 233
The power required to grind wheat ....................... 233
Smeaton's 1759 measurements using model windmills ....... 234
Coulomb's 1781 measurements on working windmills ........ 236
Dutch measurements on windmills in the 1920s and
1930s ................................................... 239
Smeaton's anomalous results ............................. 241
The power available from traditional windmills .......... 243
Comparison with drag-driven Persian windmills ........... 245
Appendix С Wind characteristics ........................... 247
Wind speed variation with height ........................ 247
Wind speed distribution ................................. 247
Notes ......................................................... 250
References .................................................... 306
Index ......................................................... 320
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