Wave Energy Converter Research Articles

Wave energy converters (WEC), as alternative power sources for marine equipment, play a crucial role in promoting the development and utilization of ocean resources. However, the harsh marine environment and the low-frequency nature of ocean waves pose substantial challenges to the lifespan and energy conversion efficiency of WECs. This paper proposes a pull-out mooring wave energy converter (POM-WEC) integrating a high-performance electromagnetic power take-off (EPTO) system. The EPTO system can convert the low-frequency and low-speed wave excitation into high-speed inertial rotational motion of the rotor. Under an excitation velocity of 0.5 m s-1, the EPTO system achieves an average output power of 9.1mW. A comprehensive methodology based on response amplitude operators and Cummins equations is developed to analyze and predict the motion response of the POM-WEC under various wave conditions. By comparing the numerical simulation with experimental data, the validity and applicability of the methodology are further verified. The influences of wave height and frequency on both the motion response of the POM-WEC and the output performance of the EPTO system are also systematically tested and evaluated. Furthermore, a self-powered wireless sensing node based on the POM-WEC is successfully developed, featuring non-volatile data storage and three distinct operation modes.

The ocean offers abundant wind and wave energy resources. This paper proposes an integrated concept that co-locates a semi-submersible floating wind platform with wave energy converters (WECs) to exploit the geographical consistency of these resources. By sharing the platform foundation and power transmission infrastructure, this integrated system enhances the utilization efficiency of marine space and renewable energy. Inspired by the principles of the Tuned Mass Damper (TMD) and leveraging mature hydraulic technologies from wave energy conversion and offshore drilling heave compensation systems, this study introduces a novel scheme. This scheme integrates a heave plate with a hydraulic Power Take-Off (PTO) system, functionally acting as a wave energy converter, to the floating platform. The primary objective is to mitigate the platform’s motion response while simultaneously generating electricity. The research investigates the motion performance improvement of this integrated platform under South China Sea conditions. The results demonstrate that the proposed WEC–PTO system not only improves the platform’s wave resistance and adaptability to deep-sea environments but also increases the overall efficiency of marine energy equipment deployment.

Geometry optimization of a two-body heaving point absorber wave energy converter based on the long-term Oman Gulf wave climate

Distributed nonlinear model predictive control of an array of wave energy converters

Numerical study of Bragg resonance reflection for wave energy converter arrays in a two-dimensional viscous wave tank

Recent advancements in wave energy converter technologies: A comprehensive review on design and performance optimization

Experimental study on power generation characteristics of a built-in bistable mechanism wave energy converter with broadband capturing performance

Comparative analysis of sliding mode and terminal sliding mode current control for Direct-Drive wave energy converters

Performance assessment of the innovative wave line magnet wave energy converter

Floating offshore wind–wave hybrid systems, as a novel structural form integrating floating wind turbine foundations and WECs, can effectively enhance the efficiency of renewable energy utilization when properly designed. A numerical model is established to investigate the dynamic responses of a wind–wave hybrid system comprising a semi-submersible FOWT and PA wave energy converters. The optimal damping values of the PTO system for the wind–wave hybrid system are determined based on an NSGA-II. Subsequently, a comparative analysis of dynamic responses is carried out for the PTO system with different states: latching, fully released, and optimal damping. Under the same extreme irregular wave conditions, the pitch motion of the FOWT with optimal damping is reduced to 71% and 50% compared to the latching and fully released states, respectively. The maximum mooring line tension in the optimal damping state is similar to that in the fully released state, but nearly 40% lower than in the latching state. This optimal control strategy not only sustains power generation but also enhances structural stability and efficiency compared to traditional survival strategies, offering a promising approach for cost-effective offshore wind and wave energy utilization.

Hydrodynamic and energy-harvesting performance of an array of taut-moored point-absorber wave energy converters

For the direct-driven wave energy converters (WEC) with time-varying disturbance and uncertain parameters of model, a maximum wave energy capture strategy based on input saturation L 1 adaptive control is proposed. By analyzing the hydrodynamic model of a direct-drive WEC and the mathematical model of permanent magnet linear synchronous generator (PMLSG), a state-space model of the direct-drive WEC is established; the maximum power capture condition is obtained by using the equivalent circuit method; the input saturation L 1 adaptive controller with µ-modification is designed considering the controller limited case, which can effectively suppress the effects of time-varying disturbances and uncertain parameters of model to make the system track the desired current, and then achieve the maximum power tracking control. The convergence proof of the observation and reference errors is given. Simulations verify the effectiveness of the proposed control strategy, and the system has good steady state tracking performance and transient performance.

In this paper, a generic computational framework, based on the generalized-mode approach, is developed for the fully coupled time-domain aero-hydro-servo-elastic analysis of Hybrid Offshore Wind and Wave Energy Systems (HOWiWaESs), consisting of a Floating Offshore Wind Turbine (FOWT) and several wave energy converters (WECs) mechanically connected to it. The FOWT’s platform and the WECs of the HOWiWaES are modeled as a single floating body with conventional rigid-body modes, while the motions of the WECs relative to the FOWT are described as additional generalized modes of motion. A numerical tool is established by appropriately modifying/extending the OpenFAST source code. The frequency-dependent exciting forces and hydrodynamic coefficients, as well as hydrostatic stiffness terms, are obtained using the traditional boundary integral equation method, whilst the generalized-mode shapes are determined by developing appropriate 3D vector shape functions. The tool is applied for a 5 MW FOWT with a spar-type floating platform and a conic WEC buoy hinged on it via a mechanical arm, and results are compared with those of other investigators utilizing the multi-body approach. Two distinctive cases of a pitching and a heaving WEC are considered. A quite good agreement is established, indicating the potential of the developed tool to model floating HOWiWaESs efficiently.

This study assesses the feasibility and profitability of marine hybrid clusters, combining wave energy converters (WECs) and offshore wind turbines (OWTs) to power households and marine aquaculture. Researchers analyzed two coastal sites: La Serena, Chile, with high and consistent wave energy resources, and Ensenada, Mexico, with moderate and more variable wave power. Two WEC technologies, Wave Dragon (WD) and Pelamis (PEL), were evaluated alongside lithium-ion battery storage and green hydrogen production for surplus energy storage. Results show that La Serena’s high wave power (26.05 kW/m) requires less hybridization than Ensenada’s (13.88 kW/m). The WD device in La Serena achieved the highest energy production, while PEL arrays in Ensenada were more effective. The PEL-OWT cluster proved the most cost-effective in Ensenada, whereas the WD-OWT performed better in La Serena. Supplying electricity for seaweed aquaculture, particularly in La Serena, proves more profitable than for households. Ensenada’s clusters generate more surplus electricity, suitable for the electricity market or hydrogen conversion. This study emphasizes the importance of tailoring emerging WEC systems to local conditions, optimizing hybridization strategies, and integrating consolidated industries, such as aquaculture, to enhance both economic and environmental benefits.

Hydrodynamic analysis of multi-cylinder floating-point-absorber wave energy converter

This paper presents an innovative approach to efficiently harvesting energy from ocean waves through a buoy-type Wave Energy Converter (WEC). The proposed methodology integrates a buoy, a Mechanical Motion Rectifier (MMR), a Motion Rectifier (MR), an Energy Storage Element (ESE), and an electric generator. A MATLAB-2023 model has been employed to assess the electrical power generated under varying wave heights and frequencies. Experimental data and numerical simulations reveal that the prototype Wave Energy Harvester (WEH) achieved a peak voltage of 6.7 V, peak power of 3.6 W, and an average power output of 8.5 mW, with an overall efficiency of 47.2% for the device’s actual size. Additionally, a theoretical analysis has been conducted to investigate the impact of incorporating additional buoys on the electrical power output.

This paper presents a power smoothing strategy for wave energy converters (WECs) by means of energy storage systems (ESS) with integrated forecasting filtering algorithms applied to their control. The oscillatory nature of wave energy leads to high variability in power output, posing significant challenges for grid integration. A case study in Tenerife, Spain, was modeled in MATLAB-Simulink (release r2020b) to evaluate the impact of prediction-enhanced smoothing filters on ESS sizing. Various forecasting algorithms were assessed, including Bayesian Neural Networks, ARMA models, and persistence models. The simulation results demonstrate that the use of forecasting algorithms substantially reduces energy storage requirements while maintaining grid stability. Specifically, the application of Bayesian Neural Networks reduced the required ESS energy by up to 36.52% compared to traditional filters. In a perfect prediction scenario, reductions of up to 53.91% were achieved. These results highlight the importance of combining appropriate filtering strategies with advanced forecasting techniques to improve the technical and economic viability of wave energy projects. The paper concludes with a parametric analysis of moving average filter windows and prediction horizons, identifying the optimal combinations for different sea conditions. In summary, this study provides practical information into reducing the storage capacity required for power smoothing in wave energy systems, thereby contributing to the mitigation of grid integration challenges that may arise with the large-scale deployment of marine renewable energy

This study introduces a novel adaptive Mechanical Wave Energy Converter (MWEC) designed to efficiently capture nearshore wave energy for sustainable electricity generation along the southeast surf coast of NEOM (135° longitude). The MWEC system features a polyvinyl chloride (PVC) cubic buoy integrated with a mechanical power take-off (PTO) mechanism, optimized for deployment in shallow waters for a depth of around 1 m. Three buoy volumes, V1: 6000 cm3, V2: 30,000 cm3, and V3: 72,000 cm3, were experimentally evaluated under consistent PTO and spring tension configurations. The findings reveal a direct relationship between buoy volume and force output, with larger buoys exhibiting greater energy capture potential, while smaller buoys provided faster and more stable response dynamics. The energy retention efficiency of the buoy–PTO system was measured at 20% for V1, 14% for V2, and 10% for V3, indicating a trade-off between responsiveness and total energy capture. Notably, the largest buoy (V3) generated a peak power output of 213 W at an average wave amplitude of 65 cm, confirming its suitability for high-energy conditions along NEOM’s surf coast. In contrast, the smaller buoy (V1) performed more effectively during periods of reduced wave activity. Wave climate data collected during November and December 2024 support a hybrid deployment strategy, utilizing different buoy sizes to adapt to seasonal wave variability. These results highlight the potential of modular, wave-adaptive mechanical systems for scalable, site-specific renewable energy solutions in coastal environments like NEOM. The proposed MWEC offers a promising path toward low-cost, low-maintenance wave energy harvesting in shallow waters, contributing to Saudi Arabia’s sustainable energy goals.

Abstract The propagation of kinetic Alfvén waves (assumed sourced from intermittent dayside reconnection) is investigated with a gyrofluid‐kinetic electron model compared with Cluster observations. These observations reveal electron distributions that are preferentially field‐aligned or field‐opposed, with signatures that are unidirectional or counterstreaming and skews that vary with the current sense. The simulations reproduce, with good fidelity, the observed local characteristics when the conditions match the observed local plasma conditions. The wave energy conversion is predominantly positive at mid‐altitudes, indicating a transfer of wave to electron energy. This conversion rate increases significantly at low‐altitudes (in the inertial Alfvén wave regime) and is accompanied by the formation of highly field‐aligned electron beams peaking at several hundred eV in energy, with a directionality that is opposite to the current sense. This low‐altitude energization results in the dissipation of the majority of the wave Poynting flux and would lead to substantial soft electron precipitation.

To mitigate electromagnetic pollution resulting from the rapid development of high-speed communication technologies, such as 5G, it is crucial to develop composite materials that combine efficient electromagnetic wave absorption (EMA) performance with environmental stability. The synergistic interactions of multifunctional components and the construction of heterogeneous interfaces are recognized as effective strategies for enhancing both the EMA capability and corrosion resistance. In this study, a mesoporous magnetic composite material was successfully synthesized, Co/NC/CNFs@MnO2 (CNCM), by in situ growing a layered MnO2 structure on the surface of ZIF-67-derived magnetic carbon nanofibers. The material achieved a minimum reflection loss (RLmin) of -74.32 dB at a matching thickness of 2.17 mm and a maximum effective absorption bandwidth (EABmax) of 6.16 GHz (10.76-16.92 GHz) of 2.04 mm. This exceptional performance arises from the synergistic effects of conductive loss, dipole polarization, interface polarization, and magnetic loss, which enhance the loss mechanisms and optimize impedance matching, thereby improving electromagnetic wave (EMW) attenuation and energy conversion efficiency. HFSS simulations further confirmed its potential for electromagnetic stealth applications, demonstrating a significant reduction in radar cross-section (RCS) of 26.8 dB·m2 at vertical incidence and up to 46.0 dB·m2 at a 45° incidence angle, indicating an excellent infrared stealth performance. Additionally, the layered MnO2 structure acts as a physical barrier, effectively preventing the penetration of corrosive media and significantly enhancing the material's corrosion resistance. This study provides valuable insights into the design of lightweight, efficient, and corrosion-resistant electromagnetic protective materials.