Wave Power Generation Research Articles

Evaluating the Dependability Measures of a Hybrid Wind–Wave Power Generation System Under Varied Weather Conditions

Evaluating the Dependability Measures of a Hybrid Wind–Wave Power Generation System Under Varied Weather Conditions

Advancements and Future Prospects in Ocean Wave Energy Harvesting Technology Based on Micro-Energy Technology.

Marine wave energy exhibits significant potential as a renewable resource due to its substantial energy storage capacity and high energy density. However, conventional wave power generation technologies often suffer from drawbacks such as high maintenance costs, cumbersome structures, and suboptimal conversion efficiencies, thereby limiting their potential. The wave power generation technologies based on micro-energy technology have emerged as promising new approaches in recent years, owing to their inherent advantages of cost-effectiveness, simplistic structure, and ease of manufacturing. This paper provides a comprehensive overview of the current research status in wave energy harvesting through micro-energy technologies, including detailed descriptions of piezoelectric nanogenerators, electromagnetic generators, triboelectric nanogenerators, dielectric elastomer generators, hydrovoltaic generators, and hybrid nanogenerators. Finally, we provide a comprehensive overview of the prevailing issues and challenges associated with these technologies, while also offering insights into the future development trajectory of wave energy harvesting technology.

Performance analysis of a novel hybrid device with floating breakwater and wave energy converter integrated

As a kind of clean energy, wave energy has attracted increasing attention in recent years. However, due to its high cost and low efficiency, wave energy has not been widely commercialized worldwide. According to previous research works, the combination of wave energy devices and floating breakwaters can reduce the cost of wave power generation devices efficiently. In this paper, a hybrid device with wave energy converter (WEC) and flexible porous floating breakwater integrated is proposed. The hydrodynamic performance of this device is studied by numerical simulation based on Reynolds-Averaged Navier–Stokes (RANS) method which has been validated through experimental results. Based on this, a series of numerical simulations are performed under different power take-off stiffness (KPTO) and different power take-off damping coefficient (CPTO) to calculate the motion and transmission coefficient of the device. By comparing the numerical results, the influence of KPTO and CPTO of the hybrid device on its wave attenuation performance and energy conversion efficiency are analyzed. The results indicate that under the incident waves of period 0.56 s and 0.89 s, the recommended value of KPTO is 3.0 N/m and 0.5 N/m respectively. While for incident waves of period 0.56s, in order to achieve better wave attenuation performance and power generation efficiency, the recommended value of CPTO should be between 10.55 Ns/m and 14.23 Ns/m. On this basis, the influence of the size of breakwater on the wave attenuation performance and power generation efficiency of the hybrid device is also discussed. Moreover, through a cost analysis, it can be inferred that the utilization of the baseline model is more economically viable.

Optimal Scheduling of Island Microgrids with Seawater Pumped Storage Plants for Multi‐Energy Complementarity

The rapid development of new energy sources, such as offshore wind power and photovoltaic power, has provided a new solution to the problem of power supply for islands far from the mainland. Wave energy is a kind of renewable energy originated from the ocean, but the existing island power supply programs seldom consider this favorable natural condition. In addition, seawater variable‐speed pumped storage is a new idea to consume offshore wind power and improve the reliability of coastal and island power systems. In view of the stochastic and intermittent nature of new energy sources, this paper adopts seawater variable‐speed pumped storage power plants as energy storage equipment, and put forward an island power supply scheme with wind power, photovoltaic power generation, wave power generation, pumped storage power plants and diesel generator sets as a multifunctional complementary isolated grid. Firstly, wave energy generators, wind farms, photovoltaic farms, pumped storage power stations and diesel generator sets are modeled separately. Then, considering their respective operating conditions, constraints and load requirements, the optimal scheduling of island microgrids with multi‐energy complementarity is constructed. Finally, based on the improved particle swarm optimization algorithm, the model is solved. According to the wind power photovoltaic and wave power output curves of several typical scenarios in an island far away from the mainland, the cost and benefit of different schemes are compared to verify the effectiveness of the optimal scheduling in this paper. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Research on Fourier Coefficient-Based Energy Capture for Direct-Drive Wave Energy Generation System Based on Position Sensorless Disturbance Suppression

In order to improve the energy capture efficiency of direct-drive wave power generation (DDWEG) systems and enhance the robustness of the reference power tracking control, a Fourier coefficient-based energy capture (FCBEC) and a position sensorless disturbance suppression (PSDS) control strategy are proposed. For energy capture, FCBEC is proposed to construct the objective function by maximizing the average power over a period of time and expanding the variables in the Fourier basis when the maximum power is captured, which is used as the basis for obtaining the reference trajectory. To address the limitations of the mechanical encoder, the position sensorless technique, based on a sliding mode observer (SMO), is used in the power tracking control, and the position information is obtained through an inverse tangent function. The perturbation caused by the inverse electromotive force error in the system is theoretically analyzed. A full-order terminal sliding mode approach is employed to design a current controller that suppresses the perturbation and ensures accurate tracking of the reference current. Simulation results show that the ocean-wave energy capture strategy proposed in this paper can make the energy captured by the PTO reach the optimal value under the impedance matching condition, and that the response speed and robustness of the full-order terminal sliding mode are better than the traditional PI control.

A Marine Experiment Using Dielectric Elastomer Generators and Comparative Study with Actual Measured Values and Theoretical Values

Power generators using dielectric elastomer (DE) transducers are inexpensive, highly efficient, lightweight, stackable, and also easy to install. Therefore, it is considered optimal for an eco-energy society and is attracting attention as a renewable energy device. In particular, DE wave power generators are characterized by the fact that it is not limited by the direction and size of waves, which is a problem with existing wave power generation. This paper presents an accurate method for measuring the energy generated by a DE generator (DEG) and compares it with the theory value obtained by calculation. The electrode materials actually used in this study were a variety of carbon-based materials (including muti-wall carbon nanotube (MWCNT) and singe-wall carbon nanotubes (SWCNT)), and the performance of DEs using these materials was compared. Furthermore, ocean experiments in actual sea areas using DEG were also conducted, and the energy conversion rate was calculated based on the electrical results.

Heterostructure channel designs for the topological interface state of surface water waves using topology optimization

The increase of the concentrated density of wave energy is conducive to improving the generation efficiency of wave power generation. Interface states induced in the heterostructure channels can be applied to concentrate the surface water wave. The optimal designs of heterostructure channels can be found through the topology optimization based on the multiple population genetic algorithm to induce a topological interface state with high transmission at the desired frequency. The introduction of the topological interface state effectively and steadily increases the wave energy density in a certain space and improves the robustness and the localization of the water wave concentrator. This topology optimization method provides a design scheme for the wave energy concentrator in the field of ocean engineering.

Power prediction of oscillating water column power generation device based on physical information embedded neural network

Due to its simplicity and high reliability, Oscillating Water Column (OWC) wave energy conversion devices hold great promise for practical applications. The optimization of OWC parameters is currently a hot research topic. In this study, we address the challenges of rapid response prediction and parameter optimization for OWC systems by developing a physics-informed neural networks (PINN) model. The influence of different physical constraints on the performance of the PINN model is investigated. Our research demonstrates that incorporating the key parameter of wave elevation in the intermediate layer enhances the interpretability, prediction accuracy, and scalability of the model but may affect its convergence. By including the prior physical knowledge of the correlation between water volume change rate and power generation efficiency into the loss function, the convergence of the neural network model can be improved, albeit with minimal impact on prediction accuracy and scalability. Additionally, introducing the critical laws discovered in subsequent analyses regarding the relationship between wave elevation distribution and power generation efficiency into the loss function enhances the convergence of the PINN model while significantly improving its scalability. In summary, by integrating various physical constraints, including key parameters, prior knowledge, and critical laws, into the neural network model, significant improvements can be achieved in the interpretability, accuracy, convergence, and scalability of the model. The findings of this study highlight the avenues through which neural network model performance can be improved from these three perspectives, aiming to provide guidance for related modeling endeavors.

Analysis of the Use of Ocean Wave Power Generation Technology as an Environmentally Friendly Energy Alternative in Indonesia

Indonesia is an archipelagic country that is geographically located between two continents and two oceans. As a country blessed with vast ocean expanses, Indonesia has great potential for marine energy sources. Ocean Wave Power Plants (PLTGL) are a type of energy that has advantages compared to other energy sources, namely that they are available throughout the ocean and are considered more environmentally friendly. However, in its use, Ocean Wave Power Plants require quite a lot of money. Apart from that, even though it is considered more environmentally friendly, ocean wave technology also has environmental impacts. This research aims to analyze the use of ocean wave power generation technology. The method used in this research is a qualitative research method with a literature study approach. The results of this research show that ocean wave power plants are a renewable energy source that has great potential to be used as an environmentally friendly alternative energy source in Indonesia

Design comparison and effects of a chamber structure on wave dissipation

ABSTRACT Among all the ocean energy sources that have been widely studied, chamber structures such as oscillating water column (OWC) technologies are effective and low-cost methods to develop hundreds of wave power generation devices as the disadvantage is its lack of efficiency. Even if the OWC system does not perform any power generation operations, it is a wave-absorbing structure. A large part of the wave energy may be blocked by the structure’s acting chamber or could be dissipated during the interaction of the waves in the air chamber, which affects the actual power generation benefit evaluation. Nevertheless, a better wave attenuation structure may present a relatively poor design of the OWC generator chamber. A series of experiments were conducted with regular and irregular wave conditions to study the effects of energy dissipation caused by a chamber structure under varied barrier and orifice designs.

Research on Maximum Power Control of Direct-Drive Wave Power Generation Device Based on BP Neural Network PID Method

Ocean wave energy is a new type of clean energy. To improve the power generation and wave energy conversion efficiency of the direct-drive wave power generation system, by addressing the issue of large output errors and poor system stability commonly associated with the currently used PID (proportional, integral, and derivative) control methods, this paper proposes a maximum power control method based on BP (back propagation) neural network PID control. Combined with Kalman filtering, this method not only achieves maximum power tracking but also reduces output ripple and tracking error, thereby enhancing the system’s control quality. This study uses a permanent magnet linear generator as the power generation device, establishes a system dynamics model, and predicts the main frequency of irregular waves through the Fast Fourier Transform method. It designs a desired current tracking curve that meets the maximum power strategy. On this basis, a comparative analysis of the control accuracy and stability of three control methods is conducted. The simulation results show that the BP neural network PID control method improves power generation and exhibits better accuracy and stability.

Multi-Time-Scale Optimal Scheduling Strategy for Marine Renewable Energy Based on Deep Reinforcement Learning Algorithm.

Surrounded by the Shandong Peninsula, the Bohai Sea and Yellow Sea possess vast marine energy resources. An analysis of actual meteorological data from these regions indicates significant seasonality and intra-day uncertainty in wind and photovoltaic power generation. The challenge of scheduling to leverage the complementary characteristics of various renewable energy sources for maintaining grid stability is substantial. In response, we have integrated wave energy with offshore photovoltaic and wind power generation and propose a day-ahead and intra-day multi-time-scale rolling optimization scheduling strategy for the complementary dispatch of these three energy sources. Using real meteorological data from this maritime area, we employed a CNN-LSTM neural network to predict the power generation and load demand of the area on both day-ahead 24 h and intra-day 1 h time scales, with the DDPG algorithm applied for refined electricity management through rolling optimization scheduling of the forecast data. Simulation results demonstrate that the proposed strategy effectively meets load demands through complementary scheduling of wave power, wind power, and photovoltaic power generation based on the climatic characteristics of the Bohai and Yellow Sea regions, reducing the negative impacts of the seasonality and intra-day uncertainty of these three energy sources on the grid. Additionally, compared to the day-ahead scheduling strategy alone, the day-ahead and intra-day rolling optimization scheduling strategy achieved a reduction in system costs by 16.1% and 22% for a typical winter day and a typical summer day, respectively.

The Energy Conversion and Coupling Technologies of Hybrid Wind–Wave Power Generation Systems: A Technological Review

Based on the mutual compensation of offshore wind energy and wave energy, a hybrid wind–wave power generation system can provide a highly cost-effective solution to the increasing demands for offshore power. To provide comprehensive guidance for future research, this study reviews the energy conversion and coupling technologies of existing hybrid Wind–wave power generation systems which have not been reported in previous publications. The working principles of various wind and wave energy conversion technologies are summarised in detail. In addition, existing energy coupling technologies are specifically classified and described. All aforementioned technologies are comprehensively compared and discussed. Technological gaps are highlighted, and future development forecasts are proposed. It is found that the integration of hydraulic wind turbines and oscillating wave energy converters is the most promising choice for hybrid wind–wave power extraction. DC and hydraulic coupling are expected to become mainstream energy coupling schemes in the future. Currently, the main technological gaps include short their operating life, low energy production, limited economic viability, and the scarcity of theoretical research and experimental tests. The field offers significant opportunities for expansion and innovation.

Analisa Pembangkit Listrik Tenaga Ombak di Daerah Pesisir Jakarta Utara

Electrical energy is energy that is really needed in modern times like now. As the population increases and the economic activity of the population increases, consumption of electrical energy increases. To overcome this problem, namely by creating a power plant with renewable energy, one example is a wave power plant. Wave power plants are plants that rely on wave energy to produce electricity. The aim of this research is to analyze the performance of wave power generators using a buoy system in the coastal area of ​​North Jakarta. By carrying out a total of 10 days of testing in 2 different places, namely Mutiara Beach and Wika Beach, all in North Jakarta. This wave power generator with a buoy system is capable of producing the highest electrical power of 24.9 volts when using a tube-style buoy at Mutiara Beach, while the lowest power is obtained when using a beam-style buoy, namely 6.65 watts at Wika Beach.

Standard log-capture differentials as performance metrics for deepwater wave power generation

As a support to performance assessment of deepwater wave energy converters, this work quantifies susceptibility of output power to short duration variations, independent of source wave statistics. Introduced as ς-metrics, the quantified measures may be a basis for technology comparisons, with possible convergence to a choice for implementation. The metrics further allow comparison between different versions of a specific converter technology, thereby helping in design revision and refinement.With power conversion represented in terms of a technology specific capture width function, the log-capture differential is defined relative to a hypothetical benchmark characterised by negligible power variability. Root-mean-square aggregation of the differential further leads to standard log-capture differentials as site independent ς-metrics for a capture-and-conversion mechanism.Study results are included in three phases. First, three established wave energy conversion technologies are analysed at respective power maximums, so as to illustrate applicability of log-capture differential and ς-metrics. Next, the metrics are analysed at fractional output power to realise converter performance at reduced variability. Finally for a given marine environment, ς-metrics are shown to be useful in projection of output power variability across technologies, together with the mean output power as fraction of rated maximum.

Nonlinear Optimal Control for a PMLSG-VSC Wave Energy Conversion Unit

This article aims to treat the nonlinear control problem for the complex dynamics of a wave energy unit (WEC) that consists of a Permanent Magnet Linear Synchronous Generator (PMLSG) and a Voltage Source Converter (VSC). The article has developed a globally stable nonlinear optimal control method for this wave power generation unit. The new method avoids complicated state-space model transformations and minimizes the energy dispersion by the control loop. A novel nonlinear optimal control method is proposed for the dynamic model of a wave energy conversion system, which includes a Permanent Magnet Linear Synchronous Generator (PMLSG) serially connected with an AC/DC three-phase voltage source converter (VSC). The dynamic model of this renewable energy system is formulated and differential flatness properties are proven about it. To apply the proposed nonlinear optimal control, the state-space model of the PMLSG-VSC wave energy conversion unit undergoes an approximate linearization process at each sampling instance. The linearization procedure relies on a first-order Taylor-series expansion and involves the computation of the system’s Jacobian matrices. It takes place at each sampling interval around a temporary operating point, which is defined by the present value of the wave energy conversion unit’s state vector and by the last sampled value of the control inputs vector. An H-infinity feedback controller is designed for the linearized model of the wave energy conversion unit. To compute the feedback gains of this controller, an algebraic Riccati equation is repetitively solved at each time step of the control algorithm. The global stability properties of the control scheme are proven through Lyapunov analysis.

Modeling and Analysis of Wave Power Generation using Permanent Magnet Linear Synchronous Generator

This paper describes ocean wave power generation by using permanent magnet linear synchronous generator. The preliminary analysis has shown that a linear generator enables substantial simplification of the mechanical system with respect to a dc generator case [1]. The linear motor has been adopted, taking into consideration the features of the incident waves and the behavior of the floating buoy. The floating buoy is placed on the ocean surface and connected to the generator. The wave energy is carried out from the movement of a buoy. An electrical conversion system is needed between the generator and the grid. For an analysis of the power system, the modeling of the linear generator and converter system was proceeded. This paper aims at studying the electrical part of the wave energy converter and study what impact the electrical system will have on the generator.

Dual-function flapping hydrofoil: Energy capture and propulsion in ocean waves

Bionic flapping hydrofoils can be utilized for either energy extraction or propulsion, which has attracted the interest of many researchers. This paper proposes a semi-active flapping hydrofoil device connected to a spring damper power takeoff (PTO) that can simultaneously capture wave energy and propel under ocean wave excitation. The effects of various PTO stiffnesses, PTO damping, and torsional stiffnesses on energy capture and propulsion are investigated using CFD simulation. The performance maps of power generation and propulsion are presented. Compared with the traditional semi-active flapping hydrofoil, the study discovered that the proposed dual-function flapping hydrofoil system could achieve higher overall efficiency. With increasing PTO damping, the overall efficiency initially rises and then falls. After optimizing the PTO parameters, it is possible to increase the overall efficiency by 32 %–86 %. By adjusting the PTO damping, the proportion of energy absorbed for electricity generation and propulsion can be redistributed. Larger torsional stiffness can compensate for the reduction in energy capture and has slight influence on propulsion power. The proposed flapping hydrofoil is expected to be implemented in small wave-powered marine robots, enabling wave propulsion and wave power generation simultaneously.

The effect of pump diameter and penstock pipe on the electric power of a hybrid generator

Ocean Wave Power Plants (WEC) are divided into 6 types, namely (1) Point Absorber, (2) Oscillating Water Column, (3) Pressure Differential Submerger, (4) Oscillating Wave Surge Converter, (5) Attenuator & Terminator, and ( 6) Removable Devices. The AquabuOY type is a type of Point Absorber type wave power generator. This type uses a long pump connected to a Pelton turbine and was developed by Finavera (Aquaenergy) Company of Canada. The AquabuOY system has a weakness in that the turbine rotation depends on the wave period that occurs. The slower the wave period occurs, the weaker the resulting turbine rotation, therefore it needs to be improved by adding a reservoir unit to obtain pressure. stability and puffiness of the unit so that the rotation produced in the turbine is much greater. With this addition, the generator will spin more quickly and stably. In addition, the addition of wind energy installed at the top of the unit means that the generator to be built will produce more energy, is more flexible, can be placed in shallow, medium or deep seas, does not require complicated foundations, is relatively cheap, is not affected by extreme weather. and can be used in all sea conditions just by attaching it to a ballast. This study examines the effect of pump diameter and outlet pipe diameter on the electrical power generated at a hybrid power plant. pump diameter variations of 8 inches, 10 inches, 12 inches and 14 inches. Variation of outlet pipe diameter 1 inch, 2 inch, 3 inch and 4 inch. In this paper, we will present a simulation of the calculation of electrical energy from wave power with variations in pontoon volume, pump diameter, and outlet pipe diameter to obtain the most optimal system size. while wind energy power generation is presented in a different pape. Calculation simulation results to get the most optimal pump diameter and outlet pipe diameter in the hybrid power plant system built.

Analysis of Unidirectional Wave Spectral Characteristics in the Northeastern Waters of Taiwan

Marine energy development has been actively promoted in recent years. Analyzing wave data in the surrounding sea areas is crucial for improving wave power generator efficiency. This study collected unidirectional wave spectrum data from the northeast coastal area of Taiwan (e.g., Pengjia Islet, Fugui Cape, and NTOU). It aimed to analyze the main wave types (i.e., wind waves, swell, or mixed sea) and their proportions during the northeast and non-northeast monsoon periods. The results indicate that swell waves dominate at the NTOU buoy, while wind waves dominate at the other two stations. In addition, the analysis of wave spectra ratios revealed a low percentage of unimodal spectra (only about 0.5%), and bimodal and unformed spectra presented as predominant. Furthermore, this study also introduced a brand new JW-J wave spectrum, which combines the JW and JONSWAP spectra to describe low-frequency (swell) and high-frequency (wind wave) systems, showing superior performance compared to the Torsethaugen spectrum. Finally, this research analyzed the JW-J spectrum parameters from the Pengjia Islet and Fugui Cape stations and applied these results to the NTOU bouy for effectively describing wind/swell wave variations.