Electricity From Wave And Tide

A concise yet technically authoritative overview of modernmarine energy devices with the goal of sustainable electricitygeneration

With 165 full-colour illustrations and photographs of devices atan advanced stage, the book provides inspiring case studies oftoday s most promising marine energy devices anddevelopments, including full-scale grid-connected prototypes testedin sea conditions. It also covers the European Marine Energy Centre(EMEC) in Orkney, Scotland, where many of the devices areassessed.

Topics discussed: * global resources drawing energy from the World swaves and tides * history of wave and tidal stream systems * theoretical background to modern developments * conversion of marine energy into grid electricity * modern wave energy converters and tidal stream energyconverters

This book is aimed at a wide readership including professionals,policy makers and employees in the energy sector needing anintroduction to marine energy. Its descriptive style and technicallevel will also appeal to students of renewable energy, and thegrowing number of people who wish to understand how marine devicescan contribute to carbon-free electricity generation in the21st century.

Review:

This thoroughly readable and attractively illustratedvolume certainly deserves a place on many a bookshelf. (Underwater Technology, 1 March 2014)

With 165 full-colour illustrations and photographs ofdevices at an advanced stage, this book is both a valuable primeron marine energy and an inspiring picture of today s mostpromising marine energy devices and developments. (Real Power magazine, 1 October 2013)

Contents: Preface ix

Acknowledgements xi

1. Introduction 1

1.1 Marine energy and Planet Earth 1

1.2 Marine resources 5

1.2.1 Waves of the world 5

1.2.2 Tides of the world 11

1.3 A piece of history 18

1.3.1 Working with waves 18

1.3.2 Tapping tides 23

1.4 Power, energy and performance 27

1.5 Into the future 34

References 37

2. Capturing marine energy 39

2.1 Ocean waves 39

2.1.1 Linear waves 39

2.1.2 Random waves 43

2.1.3 Wave spectra48

2.1.4 Wave modification 52

2.1.5 Wave measurement 56

2.2 Wave energy conversion 59

2.2.1 Introductory 59

2.2.2 Types of wave energy converter 60

2.2.3 Principles of wave energy capture 62

2.2.3.1 Floating devices 62

2.2.3.2 Tuning and damping 64

2.2.3.3 When waves meet WECs 68

2.3 Tidal streams 71

2.3.1 Hydrodynamics 71

2.3.2 Tidal harmonics 76

2.3.3 Predicting tidal streams 83

2.4 Tidal stream energy conversion 86

2.4.1 Introductory 86

2.4.2 Tidal stream turbines 89

2.4.2.1 Turbine sizes and power ratings 89

2.4.2.2 Extracting energy: the Betz Limit 93

2.4.2.3 Lift and drag 96

2.4.2.4 Rotor speed and power coefficient 102

2.4.3 Turbine siting 105

2.5 Research and development 108

2.5.1 Models and test tanks 108

2.5.2 The European Marine Energy Centre (EMEC) 111

2.5.2.1 Wave and tidal test sites 111

2.5.2.2 Research activities 121

References 124

3. Generating electricity 125

3.1 Introductory 125

3.2 Power take-off 126

3.3 AC electricity 130

3.4 Generators 141

3.4.1 Introductory 141

3.4.2 Synchronous generators 147

3.4.3 Asynchronous generators 151

3.4.3.1 Squirrel-cage and wound-rotor induction machines 151

3.4.3.2 Doubly-fed induction generators 157

3.4.4 Linear motion generators 162

3.5 Connecting to the grid 166

3.5.1 Setting the scene 166

3.5.2 Grid strength and fault levels 169

3.5.3 Electrical quality 173

3.6 Large-scale renewable energy 175

3.6.1 Introductory 175

3.6.2 Intermittency and variability176

3.6.3 Capacity credit and backup generation 179

References 183

4. Case studies: Wave energy converters 185

4.1 Introductory 185

4.2 Case studies 186

4.2.1 Pelamis 186

4.2.2 Oyster 192

4.2.3 Limpet andMutriku 199

4.2.4 Wave Dragon 205

4.2.5 PowerBuoy(R) 211

4.2.6 Penguin 216

References 221

5. Case studies: Tidal stream energy converters 223

5.1 Introductory 223

5.2 Case studies 224

5.2.1 Andritz Hydro Hammerfest 224

5.2.2 Atlantis Resources 229

5.2.3 Marine Current Turbines 234

5.2.4 OpenHydro 240

5.2.5 Pulse Tidal 245

5.2.6 Scotrenewables Tidal Power 251

5.2.7 Tidal Generation 258

References 262

Index 263



Author Biography:

Dr Paul A. Lynn, Consultant, UK

Paul Lynn was Founding Managing Editor of the successful andhighly prestigious Wiley journal, Progress inPhotovoltaics,from 1993 until 2006. He was formally AssistantLecturer at Imperial College London and Lecturer and Reader inElectrical and Electronic Engineering at the University of Bristolfrom 1969 until 1984.

As a retired academic, Paul Lynn s continued interest inrenewable energy includes designing and building solar-poweredboats. He designed and constructed the catamaran that completed thefirst ever solar-powered voyage along the non-Tidal Thames in 2003.He was awarded 1st and 2nd prizes in theSustainable Transport section at the Royal Bath & West show in2008 for two more recent solar catamarans.

Paul Lynn has written six technical books to date and is authorof over 50 technical papers and articles.