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Open AccessEditorial

A Helicopter View of the Special Issue on Wave Energy Converters

by Diego Vicinanza and Mariano Buccino

Sustainability 2017, 9(2), 297; https://doi.org/10.3390/su9020297 - 17 Feb 2017

Cited by 1 | Viewed by 4114

Abstract

This paper intends to provide the reader with an overview of the Special Issue on Wave Energy Converters. Through 16 contributions from authors of 10 different countries, a number of key topics have been tackled, including resource assessment, engineering design, and financial analysis. [...] Read more.

This paper intends to provide the reader with an overview of the Special Issue on Wave Energy Converters. Through 16 contributions from authors of 10 different countries, a number of key topics have been tackled, including resource assessment, engineering design, and financial analysis. As a whole, the Special Issue forms an interesting and helpful compendium on the state of the art of wave energy extraction and exploitation. Full article

(This article belongs to the Special Issue Wave Energy Converters)

Research

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8238 KiB

Open AccessArticle

Offshore Wind and Wave Energy Assessment around Malè and Magoodhoo Island (Maldives)

by Pasquale Contestabile, Enrico Di Lauro, Paolo Galli, Cesare Corselli and Diego Vicinanza

Sustainability 2017, 9(4), 613; https://doi.org/10.3390/su9040613 - 14 Apr 2017

Cited by 48 | Viewed by 10759

Abstract

The Maldives are situated in the remote equatorial Indian Ocean, covering 900 km from north to south. The 26 coral atolls forming the archipelago are composed of sand and coral with a maximum height of about 2.30 m above the mean sea level. [...] Read more.

The Maldives are situated in the remote equatorial Indian Ocean, covering 900 km from north to south. The 26 coral atolls forming the archipelago are composed of sand and coral with a maximum height of about 2.30 m above the mean sea level. Periodic flooding from storm surges and the frequent freshwater scarcity are perceived by the population and the economic operators as the major environmental stresses. Moreover, the strong dependence on imported fossil fuels increases, even more, the environmental concerns. Diesel, in fact, still represents the main source of power generation, typically through privately managed small diesel sets. The real challenge for this area is to promote the environmental quality with socioeconomic growth. The present study aims to evaluate the strategic effectiveness to face these issues by wave and offshore wind energy. Resources using a 10-year hindcast dataset are here examined. The annual offshore wave power was found to range between 8.46 kW/m and 12.75 kW/m, while the 10 m and 100 m mean wind power density is respectively 0.08 kW/m² and 0.16 kW/m². Based on these results, an environmentally and socio-economically sustainable best-case scenario is constructed and two atoll islands (Malè and Magoodhoo) are specifically investigated. As a result, multifunctional structures and multi-use systems, which combine power generation, desalinization and coastal defence, are strongly recommended. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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1247 KiB

Open AccessArticle

Numerical Modeling and 3D Investigation of INWAVE Device

by Seung Kwan Song, Yong Jun Sung and Jin Bae Park

Sustainability 2017, 9(4), 523; https://doi.org/10.3390/su9040523 - 30 Mar 2017

Cited by 2 | Viewed by 4361

Abstract

In this article, numerical studies on a tightly moored point absorber type wave energy converter called INWAVE are presented. This system consists of a buoy, subsea pulleys, and a power take off (PTO) module. The buoy is moored by three ropes that pass [...] Read more.

In this article, numerical studies on a tightly moored point absorber type wave energy converter called INWAVE are presented. This system consists of a buoy, subsea pulleys, and a power take off (PTO) module. The buoy is moored by three ropes that pass through the subsea pulleys to the PTO module. Owing to the counterweight in the PTO module, a constant tension, which provides a horizontal restoring force to the buoy, is constantly applied to the rope. As waves pass by, the buoy is subjected to six degrees of freedom motion, consisting of surge, heave, sway, roll, pitch, and yaw, which causes reciprocating motion in the three mooring ropes. The PTO module converts the motion of the ropes into electric power. This process is expressed as a dynamic equation based on Newtonian mechanics and the performance of the device is analyzed using time domain simulation. We introduce the concept of virtual torsion spring in order to prevent the impact error in the ratchet gear modules which convert bidirectional motion of rope drum into unidirectional rotary motion. The three-dimensional geometrical relationship between the ropes and the buoy is investigated, and the effects of the angle of the mooring rope and the direction of wave propagation are addressed to determine the interaction between the tension of the rope and the buoy. Results have shown that the mooring rope angle has a large impact on the power extraction. The simulation results present a useful starting point for future experimental work. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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2699 KiB

Open AccessArticle

Experimental Validation of a Wave Energy Converter Array Hydrodynamics Tool

by Pau Mercadé Ruiz, Francesco Ferri and Jens Peter Kofoed

Sustainability 2017, 9(1), 115; https://doi.org/10.3390/su9010115 - 14 Jan 2017

Cited by 30 | Viewed by 6761

Abstract

This paper uses experimental data to validate a wave energy converter (WEC) array hydrodynamics tool developed within the context of linearized potential flow theory. To this end, wave forces and power absorption by an array of five-point absorber WECs in monochromatic and panchromatic [...] Read more.

This paper uses experimental data to validate a wave energy converter (WEC) array hydrodynamics tool developed within the context of linearized potential flow theory. To this end, wave forces and power absorption by an array of five-point absorber WECs in monochromatic and panchromatic waves were measured from a set of deep-water wave basin experimental tests. Unlike the few other examples of WEC array experimental campaigns, the power take-off (PTO) system of each WEC was simulated by means of advanced equipment capable of accurately reproducing linear control strategies and, thereby, reducing the uncertainty in the physical model. Experimental measurements are then compared with numerical predictions showing reasonable agreement; the measured trends are, in the same way, well captured by the numerical predictions. Further analysis demonstrates that the developed tool can predict, on the safe side, wave forces and power absorption with less than 17.5% and 23.0% error, respectively, for more than 68% of the predictions. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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2742 KiB

Open AccessArticle

Experimental Test and Simulations on a Linear Generator-Based Prototype of a Wave Energy Conversion System Designed with a Reliability-Oriented Approach

by Valeria Boscaino, Giovanni Cipriani, Vincenzo Di Dio, Vincenzo Franzitta and Marco Trapanense

Sustainability 2017, 9(1), 98; https://doi.org/10.3390/su9010098 - 11 Jan 2017

Cited by 18 | Viewed by 6555

Abstract

In this paper, we propose a reliability-oriented design of a linear generator-based prototype of a wave energy conversion (WEC), useful for the production of hydrogen in a sheltered water area like Mediterranean Sea. The hydrogen production has been confirmed by a lot of [...] Read more.

In this paper, we propose a reliability-oriented design of a linear generator-based prototype of a wave energy conversion (WEC), useful for the production of hydrogen in a sheltered water area like Mediterranean Sea. The hydrogen production has been confirmed by a lot of experimental testing and simulations. The system design is aimed to enhance the robustness and reliability and is based on an analysis of the main WEC failures reported in literature. The results of this analysis led to some improvements that are applied to a WEC system prototype for hydrogen production and storage. The proposed WEC system includes the electrical linear generator, the power conversion system, and a sea-water electrolyzer. A modular architecture is conceived to provide ease of extension of the power capability of the marine plant. The experimental results developed on the permanent magnet linear electric generator have allowed identification of the stator winding typology and, consequently, ability to size the power electronics system. The produced hydrogen has supplied a low-power fuel cell stack directly connected to the hydrogen output from the electrolyzer. The small-scale prototype is designed to be installed, in the near future, into the Mediterranean Sea. As shown by experimental and simulation results, the small-scale prototype is suitable for hydrogen production and storage from sea water in this area. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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6268 KiB

Open AccessArticle

Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

by Louise O’Boyle, Björn Elsäßer and Trevor Whittaker

Sustainability 2017, 9(1), 70; https://doi.org/10.3390/su9010070 - 5 Jan 2017

Cited by 22 | Viewed by 5969

Abstract

Wave energy converters (WECs) inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local [...] Read more.

Wave energy converters (WECs) inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local wave field and coastal environment. Assessment of these effects is necessary to inform decisions on the layout of wave farms for optimum power output and minimum environmental impact, as well as on potential site selection. An experimental campaign to map, at high resolution, the wave field variation around arrays of 5 oscillating water column WECs and a methodology for extracting scattered and radiated waves is presented. The results highlight the importance of accounting for the full extent of the WEC behavior when assessing impacts on the wave field. The effect of radiated waves on the wave field is not immediately apparent when considering changes to the entire wave spectrum, nor when observing changes in wave climate due to scattered and radiated waves superimposed together. The results show that radiated waves may account for up to 50% of the effects on wave climate in the near field in particular operating conditions. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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6055 KiB

Open AccessArticle

Economic Assessment of Overtopping BReakwater for Energy Conversion (OBREC): A Case Study in Western Australia

by Pasquale Contestabile, Enrico Di Lauro, Mariano Buccino and Diego Vicinanza

Sustainability 2017, 9(1), 51; https://doi.org/10.3390/su9010051 - 30 Dec 2016

Cited by 60 | Viewed by 10815

Abstract

This paper constructs an optimal configuration assessment, in terms of the financial returns, of the Overtopping BReakwater for wave Energy Conversion (OBREC). This technology represents a hybrid wave energy harvester, totally embedded in traditional rubble mound breakwaters. Nine case studies along the southern [...] Read more.

This paper constructs an optimal configuration assessment, in terms of the financial returns, of the Overtopping BReakwater for wave Energy Conversion (OBREC). This technology represents a hybrid wave energy harvester, totally embedded in traditional rubble mound breakwaters. Nine case studies along the southern coast of Western Australia have been analysed. The technique provides tips on how to estimate the quality of the investments, for benchmarking with different turbine strategy layouts and overlapping with the costs of traditional rubble mound breakwaters. Analyses of the offshore and nearshore wave climate have been studied by a high resolution coastal propagation model, forced with wave data from the European Centre for Medium-Range Weather Forecasts (ECMWF). Inshore wave conditions have been used to quantify the exploitable resources. It has been demonstrated that the optimal investment strategy is nonlinearly dependent on potential electricity production due to outer technical constraints. The work emphasizes the importance of integrating energy production predictions in an economic decision framework for prioritizing adaptation investments. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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8350 KiB

Open AccessArticle

Wave Energy Exploitation System Integrated in the Coastal Structure of a Mediterranean Port

by Stefania Naty, Antonino Viviano and Enrico Foti

Sustainability 2016, 8(12), 1342; https://doi.org/10.3390/su8121342 - 20 Dec 2016

Cited by 51 | Viewed by 6577

Abstract

A feasibility study for installing Wave Energy Converters (WECs) in a Mediterranean port is presented here. The final aim is to evaluate the possibility of building a green touristic infrastructure in a site having ordinary wave energy. In particular, the site of interest [...] Read more.

A feasibility study for installing Wave Energy Converters (WECs) in a Mediterranean port is presented here. The final aim is to evaluate the possibility of building a green touristic infrastructure in a site having ordinary wave energy. In particular, the site of interest is Giardini Naxos, which is located in the northern Ionian coast of the island of Sicily (Italy). A preliminary estimation of the available energy has been carried out. The chosen type of WEC device is the Oscillating Water Column (OWC) system, which is found here to allow for good integration with the vertical breakwater needed for the extension of the existing port. Its feasibility is evaluated from the structural and economic point of view. Towards this aim, the system is tested in the laboratory for estimating the reflection coefficients and the pressures on the structure, which allow us to carry out the optimization of the OWC breakwater. Furthermore, the air turbine noise is estimated and an attenuation chamber is designed to reduce such noise to within acceptable levels. The economic feasibility study allows for an evaluation of the recuperation period of the investment, which is slightly less than the service life of the WEC device. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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3037 KiB

Open AccessArticle

Laboratory Tests in the Development of WaveCat

by James Allen, Konstantinos Sampanis, Jian Wan, Deborah Greaves, Jon Miles and Gregorio Iglesias

Sustainability 2016, 8(12), 1339; https://doi.org/10.3390/su8121339 - 19 Dec 2016

Cited by 18 | Viewed by 5768

Abstract

WaveCat, a novel overtopping Wave Energy Converter, was tested with the aim of determining its performance under different sea states, establishing a starting point for optimisation of the device, numerical model validation and proof-of-concept for the control systems. The tests were carried out [...] Read more.

WaveCat, a novel overtopping Wave Energy Converter, was tested with the aim of determining its performance under different sea states, establishing a starting point for optimisation of the device, numerical model validation and proof-of-concept for the control systems. The tests were carried out at a 1:30 scale in the Ocean Basin of the COAST Laboratory at University of Plymouth. A state-of-the-art control system was implemented, and overtopping rates and device motions were recorded alongside the wave field. It was observed that power generation is dependent on both the wave height and period, with smaller periods tending to produce greater overtopping rates, and therefore greater power generation, for the same wave height. Due to time constraints in the laboratory, only one configuration of draft/freeboard was tested; with this configuration, overtopping occurred under significant wave heights of 0.083 m or more, corresponding to 2.5 m or more in prototype values. These experimental results form the basis for future development and optimisation of WaveCat. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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1587 KiB

Open AccessArticle

Wave Climate Resource Analysis Based on a Revised Gamma Spectrum for Wave Energy Conversion Technology

by Jeremiah Pastor and Yucheng Liu

Sustainability 2016, 8(12), 1321; https://doi.org/10.3390/su8121321 - 14 Dec 2016

Cited by 39 | Viewed by 5522

Abstract

In order to correctly predict and evaluate the response of wave energy converters (WECs), an accurate representation of wave climate resource is crucial. This paper gives an overview of wave resource modeling techniques and applies a methodology to estimate the naturally available and [...] Read more.

In order to correctly predict and evaluate the response of wave energy converters (WECs), an accurate representation of wave climate resource is crucial. This paper gives an overview of wave resource modeling techniques and applies a methodology to estimate the naturally available and technically recoverable resource in a given deployment site. The methodology was initially developed by the Electric Power Research Institute (EPRI), which uses a modified gamma spectrum to interpret sea state hindcast parameter data produced by National Oceanic and Atmospheric Administration’s (NOAA’s) WaveWatch III. This gamma spectrum is dependent on the calibration of two variables relating to the spectral width parameter and spectral peakedness parameter. In this study, this methodology was revised by the authors to increase its accuracy in formulating wavelength. The revised methodology shows how to assess a given geographic area’s wave resource based on its wave power density and total annual wave energy flux. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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9722 KiB

Open AccessArticle

Wave Energy Assessment and Performance Estimation of State of the Art Wave Energy Converters in Italian Hotspots

by Valentina Vannucchi and Lorenzo Cappietti

Sustainability 2016, 8(12), 1300; https://doi.org/10.3390/su8121300 - 10 Dec 2016

Cited by 65 | Viewed by 7454

Abstract

This paper presents an assessment of offshore wave energy potential at the scale of the whole Mediterranean Sea. The offshore wave data were propagated, by means of numerical modeling, toward four Italian coastal areas, namely stretches of coast of Tuscany, Liguria, Sardinia and [...] Read more.

This paper presents an assessment of offshore wave energy potential at the scale of the whole Mediterranean Sea. The offshore wave data were propagated, by means of numerical modeling, toward four Italian coastal areas, namely stretches of coast of Tuscany, Liguria, Sardinia and Sicily. For each area, the wave power and the monthly, seasonal and annual variability at water depths of 50 m and 15 m were analyzed and hotspots were located. The results show strong variability of the wave energy potential from point to point of the same area thus highlighting the need for spatially detailed analysis. The higher values of wave energy potential are located in the hotspots of Sardinia and Sicily, at 11.4 kW/m and 9.1 kW/m, respectively. The Tuscany and the Liguria hotspots are characterized, respectively, by 4.7 kW/m and 2.0 kW/m. In order to point out which state of the art WEC is best suited for the Italian areas, the performances of six different state of the art Wave Energy Converters (WECs) were evaluated. Finally, a comparison of the performances of each WEC in the selected Italian sites and in some European (EU) oceanic sites was conducted. The energy potential in the most energetic EU oceanic site, among those here investigated, is up to 38-times greater than the potentials in the studied Italian areas but the power output, of the best WEC technology, is no more than nine times greater. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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2350 KiB

Open AccessArticle

Critical Factors Influencing Viability of Wave Energy Converters in Off-Grid Luxury Resorts and Small Utilities

by Aksel Botne Sandberg, Eirik Klementsen, Gerrit Muller, Adrian De Andres and Jéromine Maillet

Sustainability 2016, 8(12), 1274; https://doi.org/10.3390/su8121274 - 7 Dec 2016

Cited by 33 | Viewed by 9064

Abstract

This paper examines technical and non-technical factors that are critical to the viability of commercialization of wave energy converters in off-grid luxury resorts and small utilities. Critical factors are found by investigating Levelized Cost of Energy, and using the tools PESTEL and Porter’s [...] Read more.

This paper examines technical and non-technical factors that are critical to the viability of commercialization of wave energy converters in off-grid luxury resorts and small utilities. Critical factors are found by investigating Levelized Cost of Energy, and using the tools PESTEL and Porter’s five competitive forces. Identified factors are then applied on three business cases to investigate their impact on viability. The results show that one of the main challenges facing off-grid commercialization is the few wave energy converter units installed per location, negating the economy of scale that large wave energy farms count on to achieve competitive cost levels. In addition, factors like current cost of energy, available wave resources, distance from shore, infrastructure, supply chain logistics, and electricity demand are found to be deciding factors for viability. Despite these challenges, it is found that there are potentially viable off-grid business cases for commercialization of wave energy converters. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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12820 KiB

Open AccessArticle

The Use of CFD in the Analysis of Wave Loadings Acting on Seawave Slot-Cone Generators

by Mariano Buccino, Fabio Dentale, Daniela Salerno, Pasquale Contestabile and Mario Calabrese

Sustainability 2016, 8(12), 1255; https://doi.org/10.3390/su8121255 - 2 Dec 2016

Cited by 22 | Viewed by 4978

Abstract

The reliability of Computational Fluid Dynamics (CFD) in reproducing qualitative and quantitative features of loadings exerted by waves on Seawave Slot-cone Generators (SSG) has been investigated via 17 numerical experiments, conducted with the suite Flow 3D. The geometry of the Wave Energy Converter [...] Read more.

The reliability of Computational Fluid Dynamics (CFD) in reproducing qualitative and quantitative features of loadings exerted by waves on Seawave Slot-cone Generators (SSG) has been investigated via 17 numerical experiments, conducted with the suite Flow 3D. The geometry of the Wave Energy Converter (WEC), as well as the characteristics of the foreshore in front of it, were identical to those used by the authors in a laboratory study, carried out on a small scale model of a pilot plant to be located along the West Norwegian coasts; the similitude of the layouts allowed an in depth comparison between the results. A good agreement has been generally found between physical and numerical experiments, apart from some aspects of the wave–structure interaction that, however, can be considered secondary for engineering purposes. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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4622 KiB

Open AccessArticle

Hydraulic Performance of an Innovative Breakwater for Overtopping Wave Energy Conversion

by Claudio Iuppa, Pasquale Contestabile, Luca Cavallaro, Enrico Foti and Diego Vicinanza

Sustainability 2016, 8(12), 1226; https://doi.org/10.3390/su8121226 - 25 Nov 2016

Cited by 54 | Viewed by 11435

Abstract

The Overtopping BReakwaterfor Energy Conversion (OBREC) is an overtopping wave energy converter, totally embedded in traditional rubble mound breakwaters. The device consists of a reinforced concrete front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The [...] Read more.

The Overtopping BReakwaterfor Energy Conversion (OBREC) is an overtopping wave energy converter, totally embedded in traditional rubble mound breakwaters. The device consists of a reinforced concrete front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted through low head turbines, using the difference between the water levels in the reservoir and the sea water level. This paper analyzes the OBREC hydraulic performances based on physical 2D model tests carried out at Aalborg University (DK). The analysis of the results has led to an improvement in the overall knowledge of the device behavior, completing the main observations from the complementary tests campaign carried out in 2012 in the same wave flume. New prediction formula are presented for wave reflection, the overtopping rate inside the front reservoir and at the rear side of the structure. Such methods have been used to design the first OBREC prototype breakwater in operation since January 2016 at Naples Harbor (Italy). Full article

(This article belongs to the Special Issue Wave Energy Converters)

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2723 KiB

Open AccessArticle

Techno-Economic Related Metrics for a Wave Energy Converters Feasibility Assessment

by Adrian De Andres, Jéromine Maillet, Jørgen Hals Todalshaug, Patrik Möller, David Bould and Henry Jeffrey

Sustainability 2016, 8(11), 1109; https://doi.org/10.3390/su8111109 - 29 Oct 2016

Cited by 62 | Viewed by 8573

Abstract

When designing “multi-MW arrays” of Wave Energy Converters (WECs), having a low number of converters with high individual power ratings can be beneficial as the Operation and Maintenance (O&M) costs may be reduced. However, having converters of small dimensions or small power ratings [...] Read more.

When designing “multi-MW arrays” of Wave Energy Converters (WECs), having a low number of converters with high individual power ratings can be beneficial as the Operation and Maintenance (O&M) costs may be reduced. However, having converters of small dimensions or small power ratings could also be beneficial, as suggested by previous works, due to a reduction in material costs as compared to power production, and the use of small, inexpensive vessels. In this work, a case study investigating the optimum size of WEC for a 20 MW array is performed. Analysis is carried out based on the CorPower Ocean technology. In this case study, firstly a Levelized Cost of Energy (LCOE) model is created. This model incorporates the latest Capital Expenditure (CAPEX) estimates for CorPower Ocean’s 250 kW prototype. Using this techno-economic model, several sizes/ratings of WEC are tested for use in a 20 MW array. Operational Expenditure (OPEX) is calculated using two different calculation approaches in order to check its influence on final indicators. OPEX is firstly calculated as a percentage of CAPEX, as shown in previous works, and secondly using a failure-repair model, taking into account individual failures of WECs in the array. Size/rating analysis is carried out for several European locations in order to establish any dependence between site location and optimal WEC size/rating. Several metrics for techno-economic assessment of marine energy converters, other than LCOE, are compared in this work. A comparison of several devices with each these metrics is performed within this study. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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Open AccessArticle

Risk vs. Reward: A Methodology to Assess Investment in Marine Energy

by John Hutcheson, Adrián De Andrés and Henry Jeffrey

Sustainability 2016, 8(9), 873; https://doi.org/10.3390/su8090873 - 31 Aug 2016

Cited by 7 | Viewed by 6062

Abstract

The majority of WEC (wave energy converter) projects are expensive and pose a large risk to a developer. Currently no developers have been successful in commercialising a WEC. So far, many wave energy feasibility studies have only considered the LCOE (levelised cost of [...] Read more.

The majority of WEC (wave energy converter) projects are expensive and pose a large risk to a developer. Currently no developers have been successful in commercialising a WEC. So far, many wave energy feasibility studies have only considered the LCOE (levelised cost of electricity), assessing investment in marine energy technologies from a purely financial point of view. No previous studies have, however, explicitly accounted for development risk as well as the LCOE to determine the feasibility of a project. This paper proposes a new methodology that can be used to account for both risk and the LCOE to give a clearer picture of the feasibility of a WEC development. By combining the LCOE and risk score for a particular development, the “value for risk” can be calculated, presented here as the “RR ratio” (“Risk/Reward ratio”). A number of case studies were chosen to test the model, investigating the RR ratio for a number of different WEC technologies and ranking them to suggest an optimal development path for the industry. Results showed that projects that combine many innovative technologies provide the best “value for risk”. These devices overall had the highest risk, suggesting that multiple developers are likely required to collaborate in order to reduce the risk down to acceptable levels for each. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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Review

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Experimental Research on Primary and Secondary Conversion Efficiencies in an Oscillating Water Column-Type Wave Energy Converter

by Tengen Murakami, Yasutaka Imai, Shuichi Nagata, Manabu Takao and Toshiaki Setoguchi

Sustainability 2016, 8(8), 756; https://doi.org/10.3390/su8080756 - 5 Aug 2016

Cited by 8 | Viewed by 5771

Abstract

For the practical application of a fixed oscillating water column (OWC)-type wave energy converter, it is necessary to develop a design method which can consider the characteristics of incident wave motion, the motion of the internal free surface affected in the structure such [...] Read more.

For the practical application of a fixed oscillating water column (OWC)-type wave energy converter, it is necessary to develop a design method which can consider the characteristics of incident wave motion, the motion of the internal free surface affected in the structure such as a partly submerged wall, the fluctuation of air pressure in an air chamber, and the rotation of the air turbine. On the other hand, the impulse turbine as the secondary conversion device in the OWC unit is expected to achieve high efficiency. In this paper, firstly, the steady air flow tests for a single-impulse turbine were conducted to grasp the characteristics of the turbine without the effect of water waves. Secondly, the 2-dimensional wave tank tests in regular waves for the performance evaluation of the fixed OWC-type wave energy converter with the same impulse turbine were conducted to obtain the data needed to make this design method. As the results, the effects of the air chamber length and the guide vane’s setting angle on the primary and secondary conversion efficiencies are clarified experimentally. Full article

(This article belongs to the Special Issue Wave Energy Converters)

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