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Frontiers in Energy

Front. Energy    2015, Vol. 9 Issue (3) : 297-310
A review on front end conversion in ocean wave energy converters
Nagulan SANTHOSH,Venkatesan BASKARAN(),Arunachalam AMARKARTHIK
Department of Mechanical Engineering, Bannari Amman Institute of Technology, Sathyamangalam 638401, India
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Harvesting the energy from ocean waves is one of the greatest attractions for energy engineers and scientists. Till date, plenty of methods have been adopted to harvest the energy from the ocean waves. However, due to technological and economical complexity, it is intricate to involve the majority of these energy harvesters in the real ocean environment. Effective utilization and sustainability of any wave energy harvester depend upon its adaptability in the irregular seasonal waves, situation capability in maximum energy extraction and finally fulfilling the economic barriers. In this paper, the front end energy conversions are reviewed in detail which is positioned in the first stage of the wave energy converter among other stages such as power take off (PTO) and electrical energy conversion. If the recent development of these front end energy conversion is well known then developing wave energy converter with economic and commercial viability is possible. The aim of this review is to provide information on front end energy conversion of a point absorber and emphasize the strategies and calamity to be considered in designing such kinds of devices to improve the energy harvesting competence. This will be useful to the engineers for speeding up the development of a matured point absorbing type wave energy converter.

Keywords wave energy converter      point absorbers      power take off (PTO)      front end energy conversion     
Corresponding Authors: Venkatesan BASKARAN   
Just Accepted Date: 19 June 2015   Online First Date: 26 August 2015    Issue Date: 11 September 2015
 Cite this article:   
Nagulan SANTHOSH,Venkatesan BASKARAN,Arunachalam AMARKARTHIK. A review on front end conversion in ocean wave energy converters[J]. Front. Energy, 2015, 9(3): 297-310.
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Fig.1  Stages of a typical wave energy converter
Fig.2  General classification of wave activated bodies (WAB)
Fig.3  OPT power buoys [6]
Buoys Design approach for front energy conversion Description
Searaser [19] Utilizing two buoys – one on the surface of the water – the other suspended underwater A piston arrangement is placed between the two buoys to drive the onshore turbine
Pelamis [20] Five tube sections linked by universal joints Five tube sections linked by universal joints which flex in two directions to drive generator through hydraulic unit
Neptune wave power [21] Floating buoy with pendulum interconnected On board electric generator driven by oscillating pendulum
Dexawave [22] Two hinged catamarans as floating buoys Electric generator driven by the oscillations produced by two hinged catamarans
AWS [23] Floating multi cell flexible membrane Turbine- generator driven by pneumatic cell membrane activated by waves
Tab.1  Various design approaches in buoys to increase the efficiency
Fig.4  Floating buoy [25]
Fig.5  Submerged buoys [27]
Fig.6  Sea floor mounted buoy [28]
Fig.7  Submerged plate buoy [29]
Fig.8  Manta WEC [30]
Fig.9  Charlotte WEC [31]
Fig.10  Mass adjustment type WEC [32]
Fig.11  OPT spar buoy [33]
Fig.12  Non-buoyant type WEC [34]
Fig.13  WEC in heave [36]
Fig.14  WEC in Surge [37]
Fig.15  WEC in sway [38]
Fig.16  Anaconda WEC [39]
Fig.17  Pelamis WEC [40]
Fig.18  Surfing WEC [41]

A—Tracks; B—paddle; C—rollers; D—electric machine

Fig.19  Gyrobalancer WEC [[43]
Fig.20  Pendulum WEC [46]
Front end energy converter Device Significances Comments
Buoys Floating Searaser [19] Searaser harnesses almost constant power;On shore power generation and simplex structure Less installation and maintenance cost and power fluctuation is minimum
Pelamis [20] Power generation is smooth and continuous;The long, thin, streamlined shape of the machine minimizes the drag and slamming forces. Machine response in storm is minimum
Neptune wave power [21] The moving parts are not exposed to the sea water and preserved from corrosion and other calamity;Scalable and movable;Modular design for cost effective manufacturing;Interchangeable components for cost effective maintenance Dynamically configurable for any offshore environment
Dexawave [22] The converter can be easily relocated Cost effective and no negative environment footprint
AWS [23] Naturally discard load and de-tunes in large wave;Acquiescent mooring system reduces wave loadings;Sealed air system prevents exposure of moving parts to environment Devices will be arranged in arrays or ‘farms’ and high range of power can be generated
Submerged Submerged [27] The device can be implemented in near-by shore applications;The device is totally submerged under water and it is prevented from the slamming forces of the waves High efficiency is achieved by phase shift through appropriate feedback control
Buoy with reference frame Sea floor mounted/anchored [5] Provide high stability Simple structure to mount the wave energy converter on sea bed
Submerged plates [29] Efficient damping Device is prevented from sea bed earthquakes since it is moored and not rigidly fixed
Other floating bodies [30-32] More than one mode of oscillation can be achieved to extract maximum energy Simple and reliable energy conversion is achieved by implementing direct drive rotary generators
Spar [33] High structural stability;Prevent the energy conversion devices from ocean environment Spar prevents the wave energy harvester from displacement during buoy movement
Non-buoyant wave energy converter Non-buoyant near shore wave energy converter [34] Maximum energy can be harvested due to high mass density of non-buoyant body;Prevent failure during extreme wave conditions and rough weather These devices are suitable for near shore applications
Wave energy converter with different modes of motion Heave [35,36] Simple mode of motion;Continuous power generation is possible despite waves being periodic Documented several years of continuous production in the sea
Surge [37] Implemented to harvest energy in shallow wave;Surge type device is installed at a shorter distance to land thus the electricity can be delivered to the grid with lower power losses These devices are suitable for near shore applications
Sway [38] Implemented to harvest energy in deep sea;Enable optimal performance;Designed to avoid exposure to extreme wave conditions;Bio inspired structure Power generated and supplied to the grid is stable and it is of utility-grade quality
Long cylinder/tube wave energy converter Flexible tubes [39] Hinges, joints are not present in these energy harvesters and hence life expectancy is more;Rubber tubes can sustain in sea environment for a longer period of time Reasonable installation cost with acceptable performance
Rigid cylinder [40] Energy extraction is increased by implementing each and every cylinder as energy harvester;Energy generation is maximized even in small waves;The energy converter is prevented from extreme conditions by reducing the system response These device are suitable for offshore environment
Surfing Wave Energy Converter Surfers [41] Anticipated to be most applicable in near shore installations Wave paddle which is incorporated in the system to harvest the wave energy is unable to remain in the wave front due to inertial and frictional loads;As the paddle passed through the wave crest negative power was absorbed from the wave field, reducing the average power capture
Inertial Sea Wave Energy Converter (ISWEC) Gyro balancers [42-44] Reliable and durable operation is achieved by operating the flywheel in a sealed floating body Non-linear coupled model (mechanics+hydrodynamics) is implemented to improve the float shape in order to maximize the power absorption;The efficiency of the device is increased by modifying the float dimensions
Pendulum wave energy converter Pendulums [45-48] Pendulum device harvest wave energy in both strokes to generate power;The system is simple and has no complicated components Continuous energy generation can be achieved using these devices
Tab.2  Significances of various front end energy converters
1 Clément A, McCullen P, Falc?o A, Fiorentino A, Gardner F, Hammarlund K, Lemonis G, Lewis T, Nielsen K, Petroncini S, Pontes M-T, Schild P, Sj?str?m B-O, S?rensen H C, Thorpe T. Wave energy in Europe: current status and perspectives. Renewable & Sustainable Energy Reviews, 2002, 6(5): 405–431
2 Pelc R, Fujita R M. Renewable energy from the ocean. Marine Policy, 2002, 26(6): 471–479
3 Langhamer O, Haikonen K, Sundberg J. Wave power—sustainable energy or environmentally costly? A review with special emphasis on linear wave energy converters. Renewable & Sustainable Energy Reviews, 2010, 14(4): 1329–1335
4 Zabihian F, Fung A S. Review of marine renewable energies: case study of Iran. Renewable & Sustainable Energy Reviews, 2011, 15(5): 2461–2474
5 Hagerman G. Wave energy resource and economic assessment for the state of Hawaii. SEASUN Power Systems, for DBEDT, Final Report. 1992
6 Drew B, Plummer A R, Sahinkaya M N. A review of wave energy converter technology. Proceedings of the Institution of Mechanical Engineers. Part A, Journal of Power and Energy, 2009, 223(8): 887–902
7 Martinelli L, Ruol P, Cortellazzo G. On mooring design of wave energy converters: the seabreath applications. In: Proceedings of 33rd Conference on Coastal Engineering. Santander, Spain, 2012, 1–6
8 Vicente P C, de O. Falc?o A F, Gato L M C, Justino P A P. Dynamics of arrays of floating point-absorber wave energy converters with inter-body and bottom slack-mooring connections. Applied Ocean Research, 2009, 31: 267–281
9 Fitzgerald J, Bergdahl L. Rigid moorings in shallow water: a wave power application. Part I: experimental verification of methods. Marine Structures, 2009, 22(4): 809–835
10 Falnes J. A review of wave-energy extraction. Marine Structures, 2007, 20(4): 185–201
11 Al-Habaibeh A, Su D, McCague J, Knight A. An innovative approach for energy generation from waves. Energy Conversion and Management, 2010, 51(8): 1664–1668
12 Ahn K K, Truong D Q, Tien H H, Yoon J I. An innovative design of wave energy converter. Renewable Energy, 2012, 42: 186–194
13 Lindroth S, Leijon M. Offshore wave power measurements—a review. Renewable & Sustainable Energy Reviews, 2011, 15(9): 4274–4285
14 Nazari M, Ghassemi H, Ghiasi M, Sayehbani M. Design of the point absorber wave energy converter for Assuluyeh Port. Iranica Journal of Energy and Environment, 2013, 4(2): 130–135
15 Rahm M. Ocean wave energy. Digital Comprehensive Summaries of Uppsala Dissertations. The Faculty of Science and Technology, Uppsala University, 2010
16 Grilli S T, Grilli A R, Bastien S P. Small buoys for energy harvesting: experimental and numerical modelling studies. In: Proceedings of the 21st International Offshore and Polar Engineering Conference. Hawaii, USA, 2011
17 Hicks D C, Pleass C M. Physical and mathematical modeling of a point absorber wave energy conversion system with nonlinear damping. Hydrodynamics of Ocean Wave-Energy Utilization, 1986, 113–124
18 Hadano K, Koirala P, Ikegami K. A refined model for float energy conversion device. In: Proceedings of the 17th International and Polar Engineering Conference. Lisbon, Portugal, 2007
19 Smith A.&nbsp;Searaser.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
20 Salter S.&nbsp;Pelamis wave.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
21 Waldron T,&nbsp;Hench S,&nbsp;William S.&nbsp;Neptune wave power.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
22 Elbae L.&nbsp;Dexawave blue ocean energy.&nbsp;2013-<month>12</month>-<day>10</day>,&nbsp;
23 Grey S.&nbsp;AWS ocean.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
24 Hadano K,&nbsp;Saito T,&nbsp;Hashida M.&nbsp;Experiment on the energy gain of floats-type wave generator.&nbsp;In:&nbsp;Proceedings of the 11th International Offshore and Polar Engineering Conference.&nbsp;Stavanger, Norway,&nbsp;2001,&nbsp;638&ndash;645
25 Taneura K,&nbsp;Nakano K,&nbsp;Koirala P,&nbsp;Hadano K.&nbsp;On the resonance characteristics of the float type wave power generation device.&nbsp;Journal of Environmental Engineering,&nbsp;2011,&nbsp;6(3):&nbsp;542&ndash;553
26 Heikkinen H,&nbsp;Lampinen M J,&nbsp;B?ling J.&nbsp;Analytical study of the interaction between waves and cylindrical wave energy converters oscillating in two modes.&nbsp;Renewable Energy,&nbsp;2013,&nbsp;50:&nbsp;150&ndash;160
27 Valério D,&nbsp;Beir?o P,&nbsp;Sá da Costa J.&nbsp;Optimisation of wave energy extraction with the Archimedes Wave Swing.&nbsp;Ocean Engineering,&nbsp;2007,&nbsp;34(17–18):&nbsp;2330&ndash;2344
28 Simply Blue Energy.&nbsp;WEC with reference frame.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
29 Berggren L,&nbsp;Johansson M.&nbsp;Hydrodynamic coefficients of a wave energy device consisting of a buoy and a submerged plate.&nbsp;Applied Ocean Research,&nbsp;1992,&nbsp;14(1):&nbsp;51&ndash;58
30 Columbia Power Technologies, Inc.&nbsp;Manta WEC.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
31 Beatty S J.&nbsp;Analysis and development of a three body heaving wave energy converter.&nbsp;Dissertation for the Bachelor’s Degree.&nbsp;Vancouver:&nbsp;University of British Columbia,&nbsp;2003
32 Orazov B,&nbsp;O’Reilly O M,&nbsp;Sava? ?. On the dynamics of a novel ocean wave energy converter.&nbsp;Journal of Sound and Vibration,&nbsp;2010,&nbsp;329(24):&nbsp;5058&ndash;5069
33 Mekhiche M,&nbsp;Edwards K A.&nbsp;Ocean power technologies power buoy: system-level design, development and validation methodology.&nbsp;In:&nbsp;Proceedings of the 2nd Marine Energy Technology Symposium.&nbsp;Seattle, WA.&nbsp;2014
34 Amarkarthik A,&nbsp;Chandrasekaran S,&nbsp;Sivakumar K,&nbsp;Sinhmar H.&nbsp;Laboratory experiment on using non-floating body to generate electrical energy from water waves.&nbsp;Frontiers in Energy,&nbsp;2012,&nbsp;6(4):&nbsp;361&ndash;365
35 Faizal M,&nbsp;Ahmed M R,&nbsp;Lee Y H.&nbsp;A design outline for floating point absorber wave energy converters.&nbsp;Advances in Mechanical Engineering,&nbsp;2014:&nbsp;1&ndash;18
36 Neils S E,&nbsp;Hansen K.&nbsp;Heave type wave energy converter.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;http://www.
37 Wave Roller.&nbsp;Extracted from web site.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
38 BioPower Systems.&nbsp;Sway type WEC.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
39 Sustainable Energy Research Group, University of Southampton.&nbsp;Anaconda wave energy converter.&nbsp;2013-<month>12</month>-<day>11</day>,&nbsp;
40 Dalton G J,&nbsp;Alcorn R,&nbsp;Lewis T.&nbsp;Case study feasibility analysis of the Pelamis wave energy convertor in Ireland, Portugal and North America.&nbsp;Renewable Energy,&nbsp;2010,&nbsp;35(2):&nbsp;443&ndash;455
41 Hazlett B,&nbsp;Inculet I,&nbsp;Inculet D.&nbsp;Electric power generation by ‘Surfing’ water waves.&nbsp;Renewable Energy,&nbsp;2009,&nbsp;34(11):&nbsp;2510&ndash;2514
42 Kanki H,&nbsp;Arii S,&nbsp;Furusawa T,&nbsp;Otoyo T.&nbsp;Development of advanced wave power generation system by applying gyroscopic moment.&nbsp;In:&nbsp;Proceedings of the 8th European Wave and Tidal Energy Conference, Uppsala, Sweden,&nbsp;2009
43 Bracco G,&nbsp;Giorcelli E,&nbsp;Mattiazzo G.&nbsp;ISWEC: a gyroscopic mechanism for wave power exploitation.&nbsp;Mechanism and Machine Theory,&nbsp;2011,&nbsp;46(10):&nbsp;1411&ndash;1424
44 Ogai S,&nbsp;Umeda S,&nbsp;Ishida H.&nbsp;An experimental study of compressed air generation using a pendulum wave energy converter.&nbsp;Journal of Hydrodynamics,&nbsp;2010,&nbsp;22(5):&nbsp;290&ndash;295
45 Schlemmer K,&nbsp;Fuchshumer F,&nbsp;B?hmer N,&nbsp;Costello R,&nbsp;Villegas C.&nbsp;Design and control of a hydraulic power take-off for an axi-symmetric heaving point absorber.&nbsp;In:&nbsp;Proceedings of European Wave and Tidal Energy Conference.&nbsp;Southampton, UK,&nbsp;2011
46 Lin Y G,&nbsp;Tu L,&nbsp;Zhang D H,&nbsp;Liu H W,&nbsp;Li W.&nbsp;A study on dual-stroke pendulum wave energy conversion technology based on a water/oil integrated transmission system.&nbsp;Ocean Engineering,&nbsp;2013,&nbsp;67:&nbsp;27&ndash;34
47 McCabe A P,&nbsp;Bradshaw A,&nbsp;Meadowcroft J A C,&nbsp;Aggidis G.&nbsp;Developments in the design of the PS Frog Mk 5 wave energy converter.&nbsp;Renewable Energy,&nbsp;2006,&nbsp;31(2):&nbsp;141&ndash;151
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