Wave Energy Power Research Articles

Variations of wave energy power in shoaling zone of Benin coastal zone

Today, we observe at the population level, that the improvement in comfort is accompanied by an increase in the electrical energy required. The predicted exhaustion of fossil energy resources maintains some speculation. Their unequal geographical distribution justifies the energy dependence of Benin overlooked from outside. So it is urgent to explore the various sources of renewable energy available to Benin. In this work, using measurements made ​​by the Millennium Challenge Account (MCA-Benin) as part of the extension of the port of Cotonou, with Boussinesq equations (Peregrine) and Stokes waves dispersion relation, we characterized the variations of various swell parameters (height, wavelength, velocities) in the shoaling zone on the study site and proceeded to estimate variations in wave energy power from deep waters to the bathymetric breaking point. Finally, the zone with high energy power (where the conversion of this energy into electrical energy would be profitable) of these waves is highlighted on the site, the local water depth at the point of breaking waves is evaluated and results obtained allowed to justify the very energetic character take by these swells on this coast when they are close to the beach.

Progress in the Development and Utilization of Wave Energy Technology Abroad

Ocean wave energy belongs to ocean surface energy- the kinetic energy and potential energy. It is a kind of clean, non-polluting, renewable new energy which has the advantage of high energy density and wide distribution. This article describes the working principle and application of several major wave energy devices (oscillating water column, tilting, raft, canard, oscillating buoy) and elaborates the wave energy technology trend. Based on the existing research and development, the paper studies the new technology, the new or modified sources in wave energy technology. Besides, this paper reveals three key issues of wave energy development and utilization technology (power generation efficiency and stability, survival and reliability, cost) and puts forward the corresponding solving methods. At last, it summarizes that the development trend of wave energy power generation technology is in the direction of high efficiency, high reliabilityand low cost. The research trend is to develop new principles or improved wave power generation technology, and consider other integrated energy power generation technology and comprehensive utilization, energy application and development from the nearshore application to the deep sea application.

Stochastic modeling of long-term and extreme value estimation of wind and sea conditions for probabilistic reliability assessments of wave energy devices

Wave energy power plants are expected to become one of the major future contributions to the sustainable electricity production. Optimal design of wave energy power plants is associated with modeling of physical, statistical, measurement and model uncertainties. This paper presents stochastic models for the significant wave height, the mean zero-crossing wave period and the wind speed for long-term and extreme estimations. The long-term estimation focuses on annual statistical distributions, the inter-annual variation of distribution parameters and the statistical uncertainty due to limited amount of data. The stochastic model for extreme value estimation covers annual extreme value distributions and the statistical uncertainty due to limited amount of available data. Furthermore, updating based on new available data is explained based on a Bayesian approach. The statistical uncertainties are estimated based on the Maximum-Likelihood method, and the extreme value estimation uses the peaks-over-threshold (POT) method. Two generic examples of reliability assessments for failure due to fatigue and extreme loads show how the stochastic model can be implemented in reliability assessments.

A New Design of Dual-Channel Wave Energy Power Device

Ocean energy is a precious pearl. However, in the exploitation of the sea of people, the available development of ocean wave energy method is too simple and the structure of the device is relatively complex. This paper examines the analysis for the direction of the waves along the coast, and designed a dual-channel ocean wave energy generation device as well as having made a detailed description of its structure and concrete working principle. The ingenious engineering design of the device can continuously generate electricity. As the waves of high and low tides will produce mechanical energy to drive the rotation of the impeller, the improved design in this paper make full use of this principle so that can produce a steady stream of electricity. Due to the inherent advantages of this device, it has great room for improvement and broad application prospects.

A Costal Wave Energy Power Station Equipment

This paper introduced a coastal wave energy power generation and its unique dual channel structure, in which two–way coastal current was transformed into single direction rotation of the impeller. Also according to coastal wave energy characteristics, the paper analyzed relationship between inshore sea water kinetic energy and the wave amplitude away from the coast. In addition, the water velocity and flow area of equipment through power generation equipment are studied.

Protection of the Island Microgrid Based on Ocean Energy

With the continuous development and utilization of Marine resources, the island’s developments get more and more attention of the state, however, the island's power supply is always a bottleneck restricting the development of its economy. Microgrid as a kind of effective supply and use of distributed generation of power system, provides an effective solution for remote island power supply. There is a big difference in output characteristic from the power system, for the distributed power mostly use power electronic interface, which provides barriers to the protection of microgrid. The paper first introduces the structure and control mode of island microgrid based on wave energy power and currents can power generation, energy storage power, then analyzes the fault characteristics of the microgrid under different control, lastly summarizes the existing two types of microgrid relay protection method: the traditional overcurrent protection method and digital network protection method based on the communication.

Research and Development of Multi Section Floating Mechanical Wave Energy Power Generation Device

In order to study the principle of wave power generation, a multi section floating mechanical wave energy power generation device and a rectifier voltage regulator circuit are designed. The device consists of multi cylinder buoys, direction changing and speed-up mechanism, generator, rectifier voltage regulator circuit and other components. According to the certain regulation of wave movement, the structure and parameters of the wave energy capture device are designed; based on the movement characteristics of wave energy capture device, the direction changing and speed-up mechanism is designed, including crank-rocker mechanism and gear mechanism. The rectifier voltage regulator circuit is designed by the law of generator output. The experiment research shows that the efficiency of wave energy power generation device is up to 45.8% under the condition of prescribed test wave.

Design and Analysis of Water Turbine that Used for Wave Energy Power Generation

In view of the current global energy shortage crisis, ocean wave energy is development potential renewable energy, which is gaining more and more attention. This paper put forward use the water turbine absorb wave energy, and then generate electricity. It focus on the compose and generate mechanism of water turbine, and design structure of water turbine, and combine ocean wave theory and the flow control equation to analysis, through the method of machine design and FLUENT simulation, finally proved the water turbine had a high efficiency and has good application prospect.

The Research of Impeller Used in Wave Energy Power Generate Equipment

At first, the impeller power generate equipment was introduced in this paper. Second, the instantaneous velocity that the wave got into the equipment and the movement of the wave in the equipment was illustrated. At last, the stress, deformation and coefficient of safety were calculated by ansys under three different height of wave.

Multi-megawatt offshore wave energy converters – electrical system configuration and generator control strategy

Considerations of the electrical system configuration and the control strategy for the wave dragon (WD) multi-megawatt (MW) offshore wave energy converter (WEC) are presented in this study. The electrical system consists of 16–20 turbine–generator–AC/DC/AC converter units. The characteristics of the low-head water-turbine and generator control strategy enabling maximum energy capture and the best performance for the MW offshore wave energy power take-off system are described in detail. Simulation results from a single turbine–generator–frequency converter unit at different turbine heads are presented at the end of the study.

Development and Lessons Practice of the Wave Power Generation Using Piezoelectric Device

The energy supply and demand balance being very unstable in Japan today, utilization of renewable energies as alternative for fossil fuels is an important issue. In this study through experiments in wave power energy conversion teaching materials for learning were developed, interest and concern were heightened and efforts were made to bring awareness of the issues closer to home. We were able to verify the students' gaining of a deeper understanding of energy problems and grasping of energy conservation concepts through the experiments in the classroom activities. The force of the wave is converted into the motion of the steel balls and the electricity is generated. This contrivance which the steel balls move quickly even in the case of the small wave has been made the equipment. The lessons practice was carried out using this teaching tool for junior high school students. In the experiment lesson, its results verified educational effect, showing that students gained higher awareness of energy issues and also were able to effect concrete instances of energy conservation that they were able to do themselves.

Stability Analysis of a Wave-Energy Conversion System Containing a Grid-Connected Induction Generator Driven by a Wells Turbine

This paper presents the dynamic-stability analyzed results of both dynamic simulations and steady-state performance of a wave-energy power generation system containing a grid-connected induction generator (IG) driven by a Wells turbine. The stator windings of the IG are connected directly to a power grid through a step-up transformer and a transmission line. A d-q axis equivalent-circuit model is employed to establish the IG, the transmission line, and the grid to derive the complete dynamic equations of the studied system under three-phase balanced loading conditions. A frequency-domain approach based on eigenvalue analysis and a time-domain scheme based on nonlinear-model simulations are both carried out to systematically determine the dynamic stability of the studied system under various operating conditions. It can be concluded from the simulation results that the studied wave-energy power generation system subject to different disturbance conditions can maintain stable operation.

Groverアルゴリズムによる空間コヒーレントな波動エネルギの集中(熱工学,内燃機関,動力など)

Numerical simulations have proved that spatially coherent wave power energy can be accumulated in a special transducer by using multiple, small, globally coupled oscillators that can implement the Grover wave algorithm. The most efficient power concentration can be achieved under temporarily random but simultaneous spatially uniform external forces. However, in the case of spatially random external forces, no power concentrations was observed in the calculation. Since the fluctuation of wind and wave power have exhibit spatial correlation, this mechanism can be utilized to increase the efficiency of power generation by concentrating spatially distributed natural power into one localized generator.

A time-domain numerical simulator for oscillating water column wave power plants

This paper presents a time-domain numerical simulator of oscillating water column (OWC) wave power plants. The whole problem (the simulation of the movements of the inner free surface due to the excitation of the outer sea-waves) is split into two subproblems: an outer one, dealing with the incident, diffracted and radiated waves, solved once for all, and an inner one, concerning the inner water volume behavior. The kernel of this simulator is a hybrid numerical method [Josset C, Clément AH, Duclos G. A hybrid method for time-domain simulation of oscillating water column wave power plants. Ocean Engineering, to appear.] which allows for the coupling of these two problems. After the validation of each part of this simulator, it was applied to the European wave energy power plant seated on Pico Island, Azores, first to estimate the annual performance of the plant, then to simulate different alternative configurations, in a way to improve the productivity.

05/02646 Design and performance analysis of impulse turbine for a wave energy power plant

05/02646 Design and performance analysis of impulse turbine for a wave energy power plant

Computational fluid dynamics analysis of a 0.6 m, 0.6 hub-to-tip ratio impulse turbine with fixed guide vanes

This paper presents the comparison of a three-dimensional Computational Fluid Dynamics (CFD) analysis with empirical performance data of a 0.6 m Impulse Turbine with Fixed Guide Vanes used for wave energy power conversion. Pro-Engineer, Gambit and Fluent 6 were used to create a 3-D model of the turbine. A hybrid meshing scheme was used with hexahedral cells in the near blade region and tetrahedral and pyramid cells in the rest of the domain. The turbine has a hub-to-tip ratio of 0.6 and results were obtained over a wide range of flow coefficients. Satisfactory agreement was obtained with experimental results. The model yielded a maximum efficiency of approximately 54% as compared to a maximum efficiency of around 49% from experiment. A degree of insight into flow behaviour, not possible with experiment, was obtained. Sizeable areas of separation on the pressure side of the rotor blade were identified toward the tip. The aim of the work is to benchmark the CFD results with experimental data and to investigate the performance of the turbine using CFD and to with a view to integrating CFD into the design process.

Experimental and computational analysis on guide vane losses of impulse turbine for wave energy conversion

This paper deals with the detailed flow analysis of impulse turbine with experimental and computed results for wave energy power conversion. Initially, several turbulence models have been used in two-dimensional (2-D) computational fluid dynamic (CFD) analysis to find a suitable model for this kind of slow speed unconventional turbine. Experiments have been conducted to validate the CFD results and also to analyze the aerodynamics at various stations of the turbine. The three-dimensional (3-D) CFD model with tip clearance has been generated to predict the internal flow and to understand the effect of tip clearance leakage flow on behavior of the turbine in design and off-design conditions. As a result, it is found from the 2-D results that the comparison between computed and experimental data is good, qualitatively and the turbulence model, standard k– ε can predict the experimental values reasonably well, especially the efficiency of the turbine. Experimental results reveal that the downstream guide vanes are more responsible for low efficiency of the turbine and it is measured that 21% average pressure is lost due to downstream guide vanes. It is proved from the 3-D CFD model with tip clearance that it can predict the experimental values quantitatively and qualitatively. Furthermore, it is estimated from the computed results that the efficiency of the turbine has been reduced about 4%, due to tip clearance leakage flow at higher flow coefficients.

Design analysis of 0.6m Impulse turbine with fixed guide vanes for wave energy power conversion

SYNOPSIS Wave energy is the most abundant source of renewable energy in the world. For the last two decades, engineers have been investigating and defining different methods for power extraction from wave motion. Two different turbines, namely the Wells turbine and Impulse turbine with guide vanes, are commonly in use around the world for wave energy power generation. The overall purpose of this research is to perform a complete design analysis of an Impulse turbine with fixed guide vanes for wave energy power generation. The ultimate goal is to optimise the performance of the turbine under actual sea conditions. This research is divided into two phases. First, to design and manufacture a 0.6m diameter Impulse turbine with fixed guide vanes with a new hub to tip ratio; then to validate this design experimentally using Computational Fluid Dynamics (CFD) and to compare the performance characteristics obtained experimentally with those obtained from CFD. The second phase is to optimise turbine blade and guide vane geometry based on theoretical, experimental and CFD analysis and finally, to manufacture and test a 2nd generation turbine, based on this optimum design. This paper presents the work done during the first phase of the research. It reports the design of a 0.6m diameter Impulse turbine with fixed guide vanes, manufacture of turbine blades using a unique method of Rapid Prototyping on a Fused Decomposition Modelling (FDM) machine, experimental analysis of the turbine and comparison of the CFD work with experiment.

Computational fluid dynamics benchmark of an impulse turbine with fixed guide vanes

This paper presents the comparison of a three dimensional Computational Fluid Dynamics (CFD) analysis with empirical performance data of a 0.6 m impulse turbine with fixed guide vanes used for wave energy power conversion. Pro-Engineer, Gambit and Fluent 6 were used to create a 3-D model of the turbine. A hybrid meshing scheme was used with hexahedral cells in the near blade region and tetrahedral and pyramid cells in the rest of the domain. The turbine has a hub-to-tip ratio of 0.6 and results were obtained over a wide range of flow coefficients. The model yielded a maximum efficiency of approximately 54% as compared to a maximum efficiency of around 49% from experiment. A degree of insight into flow behaviour, not possible with experiment, was obtained.

Design and performance analysis of impulse turbine for a wave energy power plant

Wave energy is the most abundant source of renewable energy in the World. For the last two decades, engineers have been investigating and defining different methods for power extraction from wave motion. Two different turbines, namely Wells turbine and impulse turbine with guide vanes, are most commonly used around the world for wave energy power generation. The ultimate goal is to optimize the performance of the turbine under actual sea conditions. The total research effort has several strands; there is the manufacture and experimental testing of new turbines using the Wave Energy Research Team's (WERT) 0.6 m turbine test rig, the theoretical and computational analysis of the present impulse turbine using a commercial software package and finally the prediction of the performance of the turbine in a representative wave power device under real sea conditions using numerical simulation. Also, the WERT 0.6 m turbine test rig was upgraded with a data acquisition and control system to test the turbine in the laboratory under real sea conditions using the computer control system. As a result, it is proven experimentally and numerically that the turbine efficiency has been raised by 7% by reducing the hub-to-tip ratio from 0.7 to 0.6. Effect of tip clearance on performance of the turbine has been studied numerically and designed tip clearance ratio of 1% has been validated. From the numerical simulation studies, it is computed that the mean conversion efficiency is reduced around 5% and 4.58% due to compressible flow and damping effects inside OWC device. Copyright © 2005 John Wiley & Sons, Ltd.