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1795 KiB

Open AccessArticle

Experimentally Based Model to Size the Geometry of a New OWC Device, with Reference to the Mediterranean Sea Wave Environment

by Luca Martinelli, Paolo Pezzutto and Piero Ruol

Energies 2013, 6(9), 4696-4720; https://doi.org/10.3390/en6094696 - 9 Sep 2013

Cited by 34 | Viewed by 8003

Abstract

This note presents the Seabreath wave energy converter, basically a multi-chamber floating oscillating water column device, and the lumped model used to size its chambers, the ducts and the turbine. The model is based on extensive testing carried out in the wave flume [...] Read more.

This note presents the Seabreath wave energy converter, basically a multi-chamber floating oscillating water column device, and the lumped model used to size its chambers, the ducts and the turbine. The model is based on extensive testing carried out in the wave flume of the University of Padova using fixed and floating models with a dummy power take off and indirect measurement of the produced power. A map with the available energy in the Mediterranean Sea is also proposed, showing possible ideal application sites. The Seabreath is finally dimensioned for a quarter scale test application in the Adriatic Sea, with a 3 kW turbine, and a capacity factor of 40%. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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1609 KiB

Open AccessArticle

Design of a Novel Experimental Facility for Testing of Tidal Arrays

by Matevz Pintar and Athanasios J. Kolios

Energies 2013, 6(8), 4117-4133; https://doi.org/10.3390/en6084117 - 12 Aug 2013

Cited by 6 | Viewed by 5719

Abstract

In order to obtain the maximum amount of energy from tidal stream extraction devices, deployment in large arrays should be studied. The area of seabed with favorable conditions is fairly limited; therefore layout spacing has to be optimized. In this paper a feasibility [...] Read more.

In order to obtain the maximum amount of energy from tidal stream extraction devices, deployment in large arrays should be studied. The area of seabed with favorable conditions is fairly limited; therefore layout spacing has to be optimized. In this paper a feasibility study for a novel experimental facility, suitable for the testing of an array of tidal devices, is presented. To avoid space and scale limitations of towing tanks, testing is proposed to be performed in large lakes or calm seas using a self-propelled vessel, which will carry an array of devices with variable spacing, creating relevant speed differences and measuring their performance and loading. Using hydrodynamic scaling laws, an appropriate size for test turbines and the range of vessel speed was determined to fulfill experimental requirements. Computational fluid dynamic simulations, using the actuator disc method, have suggested a suitable turbine array configuration to resemble real application conditions. A simplified model of the vessel was analyzed using the finite elements method to determine the main scantlings. The hull resistance calculated by empirical formulae was found to be negligible compared to the resistance of the tested turbine. It was confirmed that turbine size and speed determined by scaling laws are also reasonable from a propulsion point of view. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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12498 KiB

Open AccessArticle

Comparison of the Experimental and Numerical Results of Modelling a 32-Oscillating Water Column (OWC), V-Shaped Floating Wave Energy Converter

by Thomas Kelly, Thomas Dooley, John Campbell and John V. Ringwood

Energies 2013, 6(8), 4045-4077; https://doi.org/10.3390/en6084045 - 8 Aug 2013

Cited by 38 | Viewed by 9477

Abstract

Combining offshore wind and wave energy converting apparatuses presents a number of potentially advantageous synergies. To facilitate the development of a proposed floating platform combining these two technologies, proof of concept scale model testing on the wave energy converting component of this platform [...] Read more.

Combining offshore wind and wave energy converting apparatuses presents a number of potentially advantageous synergies. To facilitate the development of a proposed floating platform combining these two technologies, proof of concept scale model testing on the wave energy converting component of this platform has been conducted. The wave energy component is based on the well-established concept of the oscillating water column. A numerical model of this component has been developed in the frequency domain, and the work presented here concerns the results of this modelling and testing. The results of both are compared to assess the validity and usefulness of the numerical model. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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5365 KiB

Open AccessArticle

Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter

by Rico H. Hansen, Morten M. Kramer and Enrique Vidal

Energies 2013, 6(8), 4001-4044; https://doi.org/10.3390/en6084001 - 7 Aug 2013

Cited by 148 | Viewed by 17289

Abstract

The Wavestar Wave Energy Converter (WEC) is a multiple absorber concept, consisting of 20 hemisphere shaped floats attached to a single platform. The heart of the Wavestar WEC is the Power Take-Off (PTO) system, converting the wave induced motion of the floats into [...] Read more.

The Wavestar Wave Energy Converter (WEC) is a multiple absorber concept, consisting of 20 hemisphere shaped floats attached to a single platform. The heart of the Wavestar WEC is the Power Take-Off (PTO) system, converting the wave induced motion of the floats into a steady power output to the grid. In the present work, a PTO based on a novel discrete displacement fluid power technology is explored for the Wavestar WEC. Absorption of power from the floats is performed by hydraulic cylinders, supplying power to a common fixed pressure system with accumulators for energy smoothing. The stored pressure energy is converted into electricity at a steady pace by hydraulic motors and generators. The storage, thereby, decouples the complicated process of wave power absorption from power generation. The core for enabling this PTO technology is implementing a near loss-free force control of the energy absorbing cylinders. This is achieved by using special multi-chambered cylinders, where the different chambers may be connected to the available system pressures using fast on/off valves. Resultantly, a Discrete Displacement Cylinder (DDC) is created, allowing near loss free discrete force control. This paper presents a complete PTO system for a 20 float Wavestar based on the DDC. The WEC and PTO is rigorously modeled from incident waves to the electric output to the grid. The resulting model of +600 states is simulated in different irregular seas, showing that power conversion efficiencies above 70% from input power to electrical power is achievable for all relevant sea conditions. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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689 KiB

Open AccessArticle

Modeling of a Point Absorber for Energy Conversion in Italian Seas

by Silvia Bozzi, Adrià Moreno Miquel, Alessandro Antonini, Giuseppe Passoni and Renata Archetti

Energies 2013, 6(6), 3033-3051; https://doi.org/10.3390/en6063033 - 20 Jun 2013

Cited by 90 | Viewed by 9997

Abstract

In the present paper, we investigate the feasibility of wave electricity production in Italian seas by the deployment of the Seabased wave energy converter (WEC). A numerical model of the coupled buoy-generator system is presented, which simulates the behavior of the wave energy [...] Read more.

In the present paper, we investigate the feasibility of wave electricity production in Italian seas by the deployment of the Seabased wave energy converter (WEC). A numerical model of the coupled buoy-generator system is presented, which simulates the behavior of the wave energy converter under regular waves of different wave heights and periods. The hydrodynamic forces, including excitation force, radiation impedance and hydrostatic force, are calculated by linear potential wave theory, and an analytical model is used for the linear generator. Two buoys of different radii are considered to explore the effect of buoy dimension on energy conversion and device efficiency. The power output is maximized by adding a submerged object to the floating buoy, in order to bring the system into resonance with the typical wave frequencies of the sites. The simulation results show a very good agreement with the published data on the Seabased WEC. The model is used to estimate energy production at eight Italian offshore locations. The results indicate that the degree of utilization of the device is higher than 20% at the two most energetic Italian sites (Alghero and Mazara del Vallo) and that it can be considerably increased if the floating body is connected to a submerged object, thanks to the resonant behavior of the WEC. In this case, the degree of utilization of the device would be higher than 40% at most of the study sites, with the highest value at Mazara del Vallo. The work enlarges the perspective, to be confirmed by experimental tests and more accurate numerical modeling, on clean electric power production from ocean waves in the Italian seas. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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7195 KiB

Open AccessArticle

Can Tidal Current Energy Provide Base Load?

by Simone Giorgi and John V. Ringwood

Energies 2013, 6(6), 2840-2858; https://doi.org/10.3390/en6062840 - 14 Jun 2013

Cited by 12 | Viewed by 8129

Abstract

Tidal energy belongs to the class of intermittent but predictable renewable energy sources. In this paper, we consider a compact set of geographically diverse locations, which have been assessed to have significant tidal stream energy, and attempt to find the degree to which [...] Read more.

Tidal energy belongs to the class of intermittent but predictable renewable energy sources. In this paper, we consider a compact set of geographically diverse locations, which have been assessed to have significant tidal stream energy, and attempt to find the degree to which the resource in each location should be exploited so that the aggregate power from all locations has a low variance. An important characteristic of the locations chosen is that there is a good spread in the peak tidal flow times, though the geographical spread is relatively small. We assume that the locations, all on the island of Ireland, can be connected together and also assume a modular set of tidal turbines. We employ multi-objective optimisation to simultaneously minimise variance, maximise mean power and maximise minimum power. A Pareto front of optimal solutions in the form of a set of coefficients determining the degree of tidal energy penetration in each location is generated using a genetic algorithm. While for the example chosen the total mean power generated is not great (circa 100 MW), the case study demonstrated a methodology that can be applied to other location sets that exhibit similar delays between peak tidal flow times. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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1716 KiB

Open AccessArticle

Characteristics of the Operational Noise from Full Scale Wave Energy Converters in the Lysekil Project: Estimation of Potential Environmental Impacts

by Kalle Haikonen, Jan Sundberg and Mats Leijon

Energies 2013, 6(5), 2562-2582; https://doi.org/10.3390/en6052562 - 21 May 2013

Cited by 23 | Viewed by 9226

Abstract

Wave energy conversion is a clean electric power production technology. During operation there are no emissions in the form of harmful gases. However there are unsolved issues considering environmental impacts such as: electromagnetism; the artificial reef effect and underwater noise. Anthropogenic noise is [...] Read more.

Wave energy conversion is a clean electric power production technology. During operation there are no emissions in the form of harmful gases. However there are unsolved issues considering environmental impacts such as: electromagnetism; the artificial reef effect and underwater noise. Anthropogenic noise is increasing in the oceans worldwide and wave power will contribute to this sound pollution in the oceans; but to what extent? The main purpose of this study was to examine the noise emitted by a full scale operating Wave Energy Converter (WEC) in the Lysekil project at Uppsala University in Sweden. A minor review of the hearing capabilities of fish and marine mammals is presented to aid in the conclusions of impact from anthropogenic sound. A hydrophone was deployed to the seabed in the Lysekil research site park at distance of 20 and 40 m away from two operational WECs. The measurements were performed in the spring of 2011. The results showed that the main noise was a transient noise with most of its energy in frequencies below 1 kHz. These results indicate that several marine organisms (fish and mammals) will be able to hear the operating WECs of a distance of at least 20 m. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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1012 KiB

Open AccessArticle

Stochastic Rating of Storage Systems in Isolated Networks with Increasing Wave Energy Penetration

by Elisabetta Tedeschi, Jonas Sjolte, Marta Molinas and Maider Santos

Energies 2013, 6(5), 2481-2500; https://doi.org/10.3390/en6052481 - 15 May 2013

Cited by 12 | Viewed by 6042

Abstract

The future success of wave energy in the renewable energy mix depends on the technical advancements of the specific components and systems, on the grid access availability and, ultimately, on the economical profitability of the investment. Small and remote islands represent an ideal [...] Read more.

The future success of wave energy in the renewable energy mix depends on the technical advancements of the specific components and systems, on the grid access availability and, ultimately, on the economical profitability of the investment. Small and remote islands represent an ideal framework for wave energy exploitation, due both to resource availability and to the current high cost of electricity that mostly relies on diesel generation. Energy storage can be the enabling technology to match the intermittent power generation from waves to the energy needs of the local community. In this paper real data from La Palma, in the Canary Islands, are used as a basis for the considered test case. As a first step the study quantifies the expected power production from Wave Energy Converter (WEC) arrays, based on data from the Lifesaver point absorber developed by Fred. Olsen. Then, a stochastic optimization approach is applied to evaluate the convenience of energy storage introduction for reducing the final cost of energy and to define the corresponding optimal rating of the storage devices. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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1535 KiB

Open AccessArticle

Modeling Evaluation of Tidal Stream Energy and the Impacts of Energy Extraction on Hydrodynamics in the Taiwan Strait

by Wei-Bo Chen, Wen-Cheng Liu and Ming-Hsi Hsu

Energies 2013, 6(4), 2191-2203; https://doi.org/10.3390/en6042191 - 18 Apr 2013

Cited by 29 | Viewed by 6870

Abstract

Tidal stream speeds in straits are accelerated because of geographic and bathymetric features. For instance, narrow channels and shallows can cause high tidal stream energy. In this study, water level and tidal current were simulated using a three-dimensional semi-implicit Eulerian-Lagrangian finite-element model to [...] Read more.

Tidal stream speeds in straits are accelerated because of geographic and bathymetric features. For instance, narrow channels and shallows can cause high tidal stream energy. In this study, water level and tidal current were simulated using a three-dimensional semi-implicit Eulerian-Lagrangian finite-element model to investigate the complex tidal characteristics in the Taiwan Strait and to determine potential locations for harnessing tidal stream energy. The model was driven by nine tidal components (M₂, S₂, N₂, K₂, K₁, O₁, P₁, Q₁, and M₄) at open boundaries. The modeling results were validated with the measured data, including water level and tidal current. Through the model simulations, we found that the highest tidal currents occurred at the Penghu Channel in the Taiwan Strait. The Penghu Channel is an appropriate location for the deployment of a tidal turbine array because of its deep and flat bathymetry. The impacts of energy extraction on hydrodynamics were assessed by considering the momentum sink approach. The simulated results indicate that only minimal impacts would occur on water level and tidal current in the Taiwan Strait if a turbine array (55 turbines) was installed in the Penghu Channel. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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2691 KiB

Open AccessArticle

Evaluation of a Model for Predicting the Tidal Velocity in Fjord Entrances

by Emilia Lalander, Paul Thomassen and Mats Leijon

Energies 2013, 6(4), 2031-2051; https://doi.org/10.3390/en6042031 - 9 Apr 2013

Cited by 8 | Viewed by 6635

Abstract

Sufficiently accurate and low-cost estimation of tidal velocities is of importance when evaluating a potential site for a tidal energy farm. Here we suggest and evaluate a model to calculate the tidal velocity in fjord entrances. The model is compared with tidal velocities [...] Read more.

Sufficiently accurate and low-cost estimation of tidal velocities is of importance when evaluating a potential site for a tidal energy farm. Here we suggest and evaluate a model to calculate the tidal velocity in fjord entrances. The model is compared with tidal velocities from Acoustic Doppler Current Profiler (ADCP) measurements in the tidal channel Skarpsundet in Norway. The calculated velocity value from the model corresponded well with the measured cross-sectional average velocity, but was shown to underestimate the velocity in the centre of the channel. The effect of this was quantified by calculating the kinetic energy of the flow for a 14-day period. A numerical simulation using TELEMAC-2D was performed and validated with ADCP measurements. Velocity data from the simulation was used as input for calculating the kinetic energy at various locations in the channel. It was concluded that the model presented here is not accurate enough for assessing the tidal energy resource. However, the simplicity of the model was considered promising in the use of finding sites where further analyses can be made. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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3537 KiB

Open AccessArticle

Optimal Constant DC Link Voltage Operation of a Wave Energy Converter

by Venugopalan Kurupath, Rickard Ekström and Mats Leijon

Energies 2013, 6(4), 1993-2006; https://doi.org/10.3390/en6041993 - 8 Apr 2013

Cited by 25 | Viewed by 7149

Abstract

This article proposes a simple and reliable damping strategy for wave powerfarm operation of small-scale point-absorber converters. The strategy is based on passiverectification onto a constant DC-link, making it very suitable for grid integration of the farm.A complete model of the system has [...] Read more.

This article proposes a simple and reliable damping strategy for wave powerfarm operation of small-scale point-absorber converters. The strategy is based on passiverectification onto a constant DC-link, making it very suitable for grid integration of the farm.A complete model of the system has been developed in Matlab Simulink, and uses real sitedata as input. The optimal constant DC-voltage is evaluated as a function of the significantwave height and energy period of the waves. The total energy output of the WEC is derivedfor one year of experimental site data. The energy output is compared for two cases, onewhere the optimal DC-voltage is determined and held constant at half-hour basis throughoutthe year, and one where a selected value of the DC-voltage is kept constant throughout theyear regardless of sea state. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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2255 KiB

Open AccessArticle

Experimental Update of the Overtopping Model Used for the Wave Dragon Wave Energy Converter

by Stefano Parmeggiani, Jens Peter Kofoed and Erik Friis-Madsen

Energies 2013, 6(4), 1961-1992; https://doi.org/10.3390/en6041961 - 3 Apr 2013

Cited by 19 | Viewed by 9195

Abstract

An overtopping model specifically suited for Wave Dragon is needed in order to improve the reliability of its performance estimates. The model shall be comprehensive of all relevant physical processes that affect overtopping and flexible to adapt to any local conditions and device [...] Read more.

An overtopping model specifically suited for Wave Dragon is needed in order to improve the reliability of its performance estimates. The model shall be comprehensive of all relevant physical processes that affect overtopping and flexible to adapt to any local conditions and device configuration. An experimental investigation is carried out to update an existing formulation suited for 2D draft-limited, low-crested structures, in order to include the effects on the overtopping flow of the wave steepness, the 3D geometry of Wave Dragon, the wing reflectors, the device motions and the non-rigid connection between platform and reflectors. The study is carried out in four phases, each of them specifically targeted at quantifying one of these effects through a sensitivity analysis and at modeling it through custom-made parameters. These are depending on features of the wave or the device configuration, all of which can be measured in real-time. Instead of using new fitting coefficients, this approach allows a broader applicability of the model beyond the Wave Dragon case, to any overtopping WEC or structure within the range of tested conditions. Predictions reliability of overtopping over Wave Dragon increased, as the updated model allows improved accuracy and precision respect to the former version. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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627 KiB

Open AccessArticle

Experimental Study Related to the Mooring Design for the 1.5 MW Wave Dragon WEC Demonstrator at DanWEC

by Stefano Parmeggiani, Jens Peter Kofoed and Erik Friis-Madsen

Energies 2013, 6(4), 1863-1886; https://doi.org/10.3390/en6041863 - 2 Apr 2013

Cited by 12 | Viewed by 7191

Abstract

The paper presents the results of an experimental study identifying the response of a 1.5 MW Wave Dragon to extreme conditions typical of the DanWEC test center. The best strategies allowing for a reduction in the extreme mooring tension have also been investigated, [...] Read more.

The paper presents the results of an experimental study identifying the response of a 1.5 MW Wave Dragon to extreme conditions typical of the DanWEC test center. The best strategies allowing for a reduction in the extreme mooring tension have also been investigated, showing that this is possible by increasing the surge natural period of the system. The most efficient strategy in doing this is to provide the mooring system with a large horizontal compliance (typically in the order of 100 s), which shall be therefore assumed as design configuration. If this is not possible, it can also be partly achieved by lowering the floating level to a minimum (survivability mode) and by adopting a negative trim position. The adoption of the design configuration would determine in a 100-year storm extreme mooring tensions in the order of 0.9 MN, 65% lower than the worst case experienced in the worst case configuration. At the same time it would lead to a reduction in the extreme motion response, resulting in heave and pitch oscillation heights of 7 m and 19° and surge excursion of 12 m. Future work will numerically identify mooring configurations that could provide the desired compliance. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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1127 KiB

Open AccessArticle

Evaluation of Various Technologies for Wave Energy Conversion in the Portuguese Nearshore

by Dina Silva, Eugen Rusu and Carlos Guedes Soares

Energies 2013, 6(3), 1344-1364; https://doi.org/10.3390/en6031344 - 5 Mar 2013

Cited by 222 | Viewed by 12529

Abstract

The objective of the present work is to perform an evaluation of the performance provided by various technologies for wave energy conversion in the Portuguese continental coastal environment. The wave climate in the target area is first analyzed using the results from three [...] Read more.

The objective of the present work is to perform an evaluation of the performance provided by various technologies for wave energy conversion in the Portuguese continental coastal environment. The wave climate in the target area is first analyzed using the results from three years of simulations with a wave prediction system based on numerical models. Based on the above data, diagrams for the bivariate distributions of the sea states occurrences, defined by the significant wave height and the energy period, are designed for both winters and whole years. On this basis, the output of five different technologies for the conversion of wave energy is assessed in some relevant locations from the Portuguese nearshore. According to the results obtained, the Portuguese continental coastal environment appears to be appropriate for the wave energy extraction. At the same time, the present work shows that the output of the wave energy conversion devices does not depend only on the average wave energy but is also dependent on the distribution of the wave energy among the sea states of different periods. For this reason, a good agreement between the characteristics of the power matrices of the wave energy converters operating in a certain place and the diagrams for the bivariate distributions of the sea states occurrences corresponding to the considered location represents a key issue in selecting the most appropriate technology for wave energy conversion. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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1202 KiB

Open AccessArticle

Tidal Current Energy Resources off the South and West Coasts of Korea: Preliminary Observation-Derived Estimates

by Do-Seong Byun, Deirdre E. Hart and Woo-Jin Jeong

Energies 2013, 6(2), 566-578; https://doi.org/10.3390/en6020566 - 24 Jan 2013

Cited by 26 | Viewed by 6991

Abstract

In this study we estimate the prospective tidal current energy resources off the south and west coasts of Korea and explore the influence of modeling tidal current energies based on 15-day versus month-long data records for regimes with pronounced perigean/apogean influences. The tidal [...] Read more.

In this study we estimate the prospective tidal current energy resources off the south and west coasts of Korea and explore the influence of modeling tidal current energies based on 15-day versus month-long data records for regimes with pronounced perigean/apogean influences. The tidal current energy resources off southern and western Korea were calculated using 29-day in situ observation data from 264 stations. The resultant annual energy densities found at each station were categorized into six groups, with a greater percentage of sites falling into the lower-energy groups: 1.1% for >10 MWh·m⁻²; 2.7% for 5 to 10 MWh·m⁻²; 6.8% for 3 to 5 MWh·m⁻²; 9.1% for 2 to 3 MWh·m⁻² and 80.3% for <2 MWh·m⁻². Analysis shows that the greatest concentration of high annual energy densities occurs in the Jeonnam Province coastal region on the western tip of southwest Korea: 23 MWh·m⁻² at Uldolmok, 15 MWh·m⁻² at Maenggol Sudo, 9.2 MWh·m⁻² at Geocha Sudo and 8.8 MWh·m⁻² at Jaingjuk Sudo. The second highest annual energy density concentration, with 16 MWh·m⁻², was found in Gyudong Suro, in Gyeonggi Province’s Gyeonggi Bay. We then used data from the 264 stations to examine the effect of perigean and apogean influences on tidal current energy density evaluations. Compared to derivations using month-long records, mean annual energy densities derived using 15-day perigean spring-neap current records alone overestimate the annual mean energy by around 10% whereas those derived using only the apogean records underestimate energy by around 12%. In particular, accuracy of the S₂ contribution to the energy density calculations is significantly affected by use of the 15-day data sets, compared to the M₂ component, which is relatively consistent. Further, annual energy density estimates derived from 29-day records but excluding the N₂ constituent underestimate the potential resource by about 5.4%. Results indicate that one month of data is required to accurately estimate tidal current energy in regimes showing pronounced perigean and apogean differences in spring-neap tidal current patterns and that inclusion of the N₂ constituent in calculations is preferable. This finding has widespread applicability for green energy resource assessments, for example, in regions of the Unites States Atlantic coast and in New Zealand. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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1351 KiB

Open AccessArticle

Non Breaking Wave Forces at the Front Face of Seawave Slotcone Generators

by Mariano Buccino, Davide Banfi, Diego Vicinanza, Mario Calabrese, Giuseppe Del Giudice and Armando Carravetta

Energies 2012, 5(11), 4779-4803; https://doi.org/10.3390/en5114779 - 19 Nov 2012

Cited by 43 | Viewed by 7069

Abstract

The Seawave Slotcone Generator (WAVEnergy SAS, 2003) is a wave energy converter based on the overtopping principle. Although it has been effectively researched during the last decade, no design tool has been supplied to estimate the hydrodynamic loads the waves exert on its [...] Read more.

The Seawave Slotcone Generator (WAVEnergy SAS, 2003) is a wave energy converter based on the overtopping principle. Although it has been effectively researched during the last decade, no design tool has been supplied to estimate the hydrodynamic loads the waves exert on its front face. In this article a set of well reliable 3D experiments has been re-analyzed, in order to get indications on possible calculation methods. It is shown that the Japanese design tools for monolithic sea dikes may be reasonably adapted to the present case. Finally a new approach is presented, which is based on the so called momentum flux principle; the resulting predictive equation fits the experimental data remarkably well. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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Review

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239 KiB

Open AccessReview

A Political, Economic, Social, Technology, Legal and Environmental (PESTLE) Approach for Risk Identification of the Tidal Industry in the United Kingdom

by Athanasios Kolios and George Read

Energies 2013, 6(10), 5023-5045; https://doi.org/10.3390/en6105023 - 27 Sep 2013

Cited by 58 | Viewed by 58035

Abstract

This paper presents a comprehensive analysis of renewable and especially tidal energy through a political, economic, social, technology, legal and environmental (PESTLE) analysis approach and by reviewing the most up to date relevant literature. The study focuses on the United Kingdom given the [...] Read more.

This paper presents a comprehensive analysis of renewable and especially tidal energy through a political, economic, social, technology, legal and environmental (PESTLE) analysis approach and by reviewing the most up to date relevant literature. The study focuses on the United Kingdom given the favourable environmental resources for such technologies; the number of different design concepts that are currently under development as well as the research funding that has been invested over the last few years. Findings of the analysis identify the risks and multiple stakeholders involved at all stages of the tidal energy projects development from the conceptualization of the design, right through to decommissioning. Many of the stakeholders present benefits to the tidal developers through funding, incentives and knowledge sharing, but at the same time they also present potential risks to the future of projects. This is mostly down to different approaches of the most important aspect of tidal energy that needs to be considered, making it hard for technologists and developers to equally address all requirements. From this research it can be concluded that several of these risks can be mitigated early on providing that particular stakeholders are involved at the correct stage of a project. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

243 KiB

Open AccessReview

2002–2012: 10 Years of Research Progress in Horizontal-Axis Marine Current Turbines

by Kai-Wern Ng, Wei-Haur Lam and Khai-Ching Ng

Energies 2013, 6(3), 1497-1526; https://doi.org/10.3390/en6031497 - 6 Mar 2013

Cited by 87 | Viewed by 10470

Abstract

Research in marine current energy, including tidal and ocean currents, has undergone significant growth in the past decade. The horizontal-axis marine current turbine is one of the machines used to harness marine current energy, which appears to be the most technologically and economically [...] Read more.

Research in marine current energy, including tidal and ocean currents, has undergone significant growth in the past decade. The horizontal-axis marine current turbine is one of the machines used to harness marine current energy, which appears to be the most technologically and economically viable one at this stage. A number of large-scale marine current turbines rated at more than 1 MW have been deployed around the World. Parallel to the development of industry, academic research on horizontal-axis marine current turbines has also shown positive growth. This paper reviews previous research on horizontal-axis marine current turbines and provides a concise overview for future researchers who might be interested in horizontal-axis marine current turbines. The review covers several main aspects, such as: energy assessment, turbine design, wakes, generators, novel modifications and environmental impact. Future trends for research on horizontal-axis marine current turbines are also discussed. Full article

(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)

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