P1992-5
Commission ofthe European Communities
energy
Wave energy R&D
Proceedings of a workshop held at Cork
1
and
2
October
1992
G. Caratti, A. T. Lewis, D. Howett
Commission of the European Communities DG XII.E.3 200, rue de la Loi B-1049 Brussels
Final report
1993
Directorate-GeneralScience, Research and Development
Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES Directorate-General XIII
Telecommunications, information Market and Exploitation of Research L-2920 Luxembourg
LEGAL NOTICE
Neither the Commission ofthe European Communities nor any person acting )n behalf ofthe Commission is responsible forthe use which might be made of
the following information.
Cataloguing data can be found at the end of this publication
Luxembourg: Office for Official Publications ofthe European Communities, 1993 ISBN 92-826-1887-0
© ECSC-EEC-EAEC, Brussels • Luxembourg, 1993
PREFACE
The exploitation of renewable energies as inexhaustible and clean sources of energy is vital if they are to substitute depleting conventional fuels and improve the quality of the environment
Research and development in most renewable energy technologies still requires considerable time and resources prior to reaching commercial maturity. Futhermore, to create a level playing field among different enegy sources, external costs should be fully accounted for in economic comparisons.
Since 1975, the Commission of European Communities has steadily been promoting research and development in renewable energy sources -particularly in solar, wind, biomass and geothermal energy- within pluri-annual programmes whereby the Commission supports up to 50% of the project costs.
In order to develop the possibility to initiate new activities in wave energy R&D, the Commission launched a preliminary action in 1991 v^dth the following objectives:
A. to identify the potential wave energy resource in the Community; B. to perform a feasibility study for a large-scale OWC device;
C. to assess tiie status of wave energy technology and future R&D priorities;
D. to encourage exchange of information between European researchers actively involved in wave energy research.
Within objective D, tiie Commission supports tiie organisation of workshops which bring together acknowledged speciaUsts in tiie field. The first such workshop was held in Cork, Ireland, on 1-2 October 1992 witiiin the beatiful premises of University College Cork, whereby about 50 experts participated from many EC and EFTA countries.
The pubblication is a collection of the papers presented at tiiis workshop. It outlines the progress achieved so far botii by tiie studies carried out in the frame of the Commission's preliminary action as well as by proyect s of other research teams in Europe.
This document should certainly serve as a useful reference guide for future wave energy research.
I am particulary grateful to Dr Tony U w i s an d Mr. David Howett, Chairman and Organiser respectively of the workshop, for their ability to combine high scientific skill with the warmest hospitality.
Finally, my personal thanks to all partecipants in the workshop for their efforts and the great enthusiasm they have shown in contributing to the success of tiiis initiative.
Dr. Wolfgang Palz
Head of the Renewable Energies Unit
Directorate-General for Science, Research and Development Commission of tlie European Communities, DG X I I , Brussels
T A B L E OF CONTENTS
PREFACE HI
EVALUATION OF THE WAVE ENERGY RESOURCE 1 T. Pontes, D. Mollison, J.C. Barge, L. Cavaleri, and GA. Athanassoulis
1. Introduction 1 2. Background: sea states and wave climates 1
3. Nearshore and coastal wave climates 4 4. Measuring and estimating waves 5 5. Methodology for resource evaluation 6
6. Future work 7 References 8
EUROPEAN PILOT PLANT STUDY 9 A.F. de O. Falcdo, T.J.T. Whittaker, T. Lewis
1. Introduction 9 2. Work in Portugal 10 3. Work in U K 12 4. Work in Ireland 15 5. Conclusions and future work 16
WAVE ENERGY CONVERTERS - GENERIC TECHNICAL EVALUATION STUDY 19 P. Randl0v
1. Preface 19 2. Introduction 20 3. Recommendations on future R&D 24
4. S trategy for future R&D 27
WAVE ENERGY CONVERTERS - PROJECT B l : SOME HYDRODYNAMIC
ASPECTS OF WAVE ENERGY CONVERTERS 31 G.P. Thomas, D.V. Evans, M. Greenhow, P. Mclver and A. Sarmento
Abstract 31 1. Introduction 31
2. Hydrodynamic fundamentals of device modelling 32
3. Survivability of devices in extreme seas 33 4. Interactions between members of an airay of devices 34
6. Oscillating Water Column hydrodynamics 7. Conclusions References 36 37 37
WAVE ENERGY CONVERTERS - PROJECT B2: DEVICE MATERIALS AND
COMPONENTS 39 K. Nielsen
Abstract 39 1. Choice of Wave Power Converters studied 39
2. Choice of components/materials studied 42
3. Methodology 42 4. Results of questionnaire inquiry 43
5. Conclusions 56 6. Recommendations for further research 57
WAVE ENERGY CONVERTERS - PROJECT B3: WAVE ENERGY POWER
CONVERSION STUDIES 59 S. Salter 1. Introduction 2. Strategies 3. Hardware 4. Energy storage 5. Fast hydraulic motors 6. Air turbines
7. Conclusions References
WAVE ENERGY CONVERTERS - PROJECT B4: ELECTRICAL ASPECTS OF WAVE POWER
W.C. Beattie
1. Introduction
2. Electrical transmission and grid interaction 102 3. Electrical machines
4. Power conversion
WAVE ENERGY CONVERTERS - PROJECT B5: METHODOLOGY FOR RELIABILITY, ECONOMIC AND ENVIRONMENTAL ASSESSMENT OF WAVE ENERGY
2. Results 112 3. Discussion 115 4. Conclusions 116 References 117
OVERVffiW OF RECENT U.K. WAVE ENERGY RESEARCH 119 / . H. Clarke
1. Objectives of D.EN/DTI renewable energy programme 119
2. Aims 119 3. Historic UK wave energy programme from 1974 to 1983 119
4. Development of point absorber devices 119 5. Development of the sea circular CLAM 120 6. Wave tank testing of the art OSPREY device 120
7. Shoreline programme 120 8. Shoreline resource assessment 121
REVffiW OF WAVE ENERGY RESEARCH IN NORWAY 125 J. Falnes
1. Initiation of wave energy research 125
2. Wave energy resource 125 3. Demonstration prototypes 125 4. K Vomer's multiresonant OWC 125 5. Norwave's Tapchan plant 126 6. Artificial wave focusing 126 7. Optimally controlled WE converters 126
8. Conclusion 127 References 127
REVffiW OF RESEARCH I N SWEDEN 129 L. Bergdahl
1. The IPS wave power buoy 129
2. The hose pump 130 3. The floating wave power vessel 131
4. Theoretical development at Chalmers 132 5. Restoration of oxygen levels in the sea 132
References 133
PROffiCT OLAS-2000 - WAVE ENERGY IN SPAIN 137 A. Matas Martinez
-THE CLAM WAVE ENERGY CONVERTER 145 L J. Duckers and F.P. Lockett
Synopsis 145 1. Introduction 145
2. TheQam 146 3. The membrane 146 4. The WeUs turbine 147 5. Mathematical modelling 148 6. Structural design 149 7. Performance and cost 150 8. Fuhire development 151
References 153
EFFICIENCY IMPROVEMENT AND DEVICE SIZE 159 R. Hunter
Summary 159 1. Intioduction and background 159
2. Phase control 160 3. Channel walls and harbour resonance 161
4. Conclusions 162 References 162
P.S. FROG MARK 2 - A PROMISING DESIGN OF WAVE ENERGY CONVERTER 171 M. French 1. General description 1^1 2. Design philosophy 1^2 3. Technical aspects ^'^^ 4. Development 5. Summary of advantages 1^'* References
PHASE CONTROL IN WAVE ENERGY GENERATION 177 N.K. Nichols
1. Introduction 2. Control mechanisms 3. Optimal control strategies
4. Practical implementation '•'^ 5. Conclusions
References
-PROGRESS I N WAVE MEASURING, TECHNIQUES AND WAVE DATA
AVAILABILITY DURING THE LAST TEN YEARS 183 T. Pitt
1. Introduction 183 2. In-situ measurements and analysis 184
3. Remote sensing-Observations and analysis 186 4. Wave transformation in shallovt' water 188
5. Conclusions 189
References 190
IPS WAVE POWER BUOY MARK IV 191 G. Fredrikson
1. Sti^ctural data 191 2. Machinery design 191 3. Calculated energy production 191
4. Power plant 192 5. Pilot plant 192
SHAWATER LTD. - VIEWPOINT OF CURRENT WAVE ENERGY 195 T. Shaw
THE SWINGING MACE 197 S. Salter
1. Introduction 197 2. Linguistic 197 3. Compartive Hydrodynamics 197
4. Powers and tensions 202
5. Cables 202 6. Energy storage 202
7. Experiments 204 8. Secondary objectives 205
9. The next steps 206
COMMENTS ON THE SHORELINE RESOURCE 207 O. L0vhaugen
ANNEX 1
List of contributors 213
