Ocean Wave Energy Harvesting Research Articles

Triboelectric Nanogenerator Drives Electrochemical Water Splitting for Hydrogen Production: Fundamentals, Progress, and Challenges.

Currently, triboelectric nanogenerators (TENGs) are drawing significant attention owing to their potential in harvesting wave and wind energy from environment as well as their capability for driving electrochemical water splitting for hydrogen fuel production. This review aims to summarize the recent progress of ocean wave and wind energy harvesting TENGs and TENG-driven electrochemical water splitting processes for hydrogen evolution reaction. For better understanding, this review begins from the fundamentals of TENG and electrochemical water splitting. And then the working principle of TENGs and mechanism of electrochemical (EC) water splitting for hydrogen evolution reaction (HER) are introduced. Subsequently the progress of output performance enhancement in ocean wave and wind energy harvesting TENGs are systematically discussed including structure design, triboelectric material selection and power management all of which are important for output performance enhancement and the integration of TENGs with electrochemical water splitting cell. Although this review focus on the promotion strategies of TENG-driven electrochemical water splitting processes for HER, challenges for water splitting are also highlighted. While envision that this review provides a deep insight and direction to the design of TENG-driven electrochemical system for promoting the hydrogen fuel production in an active, economical manner.

A Self‐Recovery Triboelectric Nanogenerator with High Breakdown Resistance for Water Wave Energy Harvesting

AbstractTriboelectric nanogenerator (TENG) harvesting ocean wave energy is an effective method to alleviate the energy crisis. However, the breakdown phenomenon is ubiquitous for the TENG with a large area of dielectric layer, which not only limits the output and reliability but also highly risks the device failure. Here, a self‐recovery TENG (SR‐TENG) featuring high breakdown resistance is designed, which achieves a high output charge density of 4.24 mC m−2 with the assistance of the charge excitation technique, as well as maintains 87% of the initial output even after six times fierce electric breakdown, minimizing the negative impacts of the breakdown phenomenon. Besides, based on the SR‐TENG, a symmetric anaconda‐shaped self‐charge excited TENG is designed for effective water wave energy harvesting. This work not only sheds light on the self‐recovery phenomenon in TENGs, but also represents a significant step toward the high performance TENG featuring high breakdown resistance and ultimate stability, accelerating the practical applications of TENG for blue energy harvesting.

Enhancement of wave energy harvesting performance by wave concentration with vertical cylinders

The performance of ocean wave energy harvesting can be enhanced by optimizing the design and operation of wave energy converters (WECs). In this experimental study, we investigate the wave interaction produced by installing additional structures to augment the power and efficiency of a WEC. Four circular cylinders are arranged in a square within a large-scale ocean engineering basin, and a duck-type rotor WEC is placed at the center of the cylinders. Several incident wave conditions are generated by varying the wavelength and wave height for a fixed wave steepness. In the absence of the rotor, the waves scattered by the cylinders become concentrated at the center of the array, increasing their amplitudes. With the rotor, wave heights in front of the rotor increase under all wave conditions from the case without the cylinders. The wave concentration produced by the cylinder array contributes positively to the power and efficiency of the rotor. The maximum power output of the rotor within a cycle improves in the entire range of the wavelength, and its efficiency over a cycle increases significantly for small wavelengths. These results are primarily attributable to changes in the temporal profile of the rotor angular velocity by the cylinder array.

Submerged and completely open solid–liquid triboelectric nanogenerator for water wave energy harvesting

AbstractTriboelectric nanogenerator (TENG) is an emerging wave energy harvesting technology with excellent potential. However, due to issues with sealing, anchoring, and difficult deployment over large areas, TENG still cannot achieve large‐scale wave energy capture. Here, a submerged and completely open solid–liquid TENG (SOSL‐TENG) is developed for ocean wave energy harvesting. The SOSL‐TENG is adapted to various water environments. Due to its simple structure, it is easy to deploy into various marine engineering facilities in service. Importantly, this not only solves the problem of difficult construction of TENG networks at present, but also effectively utilizes high‐quality wave energy resources. The working mechanism and output performance of the SOSL‐TENG are systematically investigated. With optimal triggering conditions, the transferred charge (Qtr) and short‐circuit current (Isc) of SOSL‐TENG are 2.58 μC and 85.9 μA, respectively. The wave tank experiment is taken for fully demonstrating the superiority of the SOSL‐TENG network in large‐scale collection and conversion of wave energy. Due to the excellent output performance, TENG can harvest wave energy to provide power for various commercial electronic devices such as LED beads, hygrothermograph, and warning lights. Importantly, the SOSL‐TENG networks realizes self‐powered for electrochemical systems, which provides a direction for energy cleanliness in industrial systems. This work provides a prospective strategy for large‐scale deployment of TENG applications, especially for harvesting wave energy in spray splash zones or at the surface of the water.image

A Kelp Inspired High‐Power Density Triboelectric Nanogenerator with Stacking Structure for Multiple Directional Ocean Wave Energy Harvesting

AbstractOcean wave energy is one of the most promising green energies in the wild. However, it is still challenging to effectively collect wave energy due to its randomness and irregularity. In this work, a kelp inspired high‐power density triboelectric nanogenerator (K‐TENG) is presented for harvesting wave energy with characteristics in multiple directions. The proposed K‐TENG consists of a series of stacked leaf‐like units. The influence of configuration parameters, including pellet diameters, pellet numbers, unit sizes, oscillation frequency, swing amplitude, and wave directions on output performances of leaf‐like units, are extensively investigated. Experimental data indicates that a single leaf‐like unit can achieve a maximum output voltage of 623.14 V as well as a maximum current of 1.48 µA and realize energy harvesting from different wave directions. A K‐TENG composed of 15 leaf‐like units demonstrates a high‐power density of 18.77 W m−3 at a wave frequency of 2.5 Hz, which successfully powers a digital watch and 414 light‐emitting diodes (LEDs). This work is hoped to provide a simple and reliable route to effectively harvest ocean wave energy.

Energy harvesting from a fiber-constrained dielectric elastomer generator embedded into a novel floating wave energy harvester

Abstract With the increasing energy demand and growing concern about greenhouse gases emissions from fossil fuel combustion, converting the ocean wave energy into the electrical energy has emerged as a promising and sustainable solution. This paper proposes a novel floating ocean wave energy harvester based on the fiber-constrained dielectric elastomer generator (DEG) arrays and investigates the energy harvesting (EH) performance of the fiber-constrained DEG embedded into the harvester. A theoretical analysis model of the fiber-constrained DEG describing the free relaxation process is developed and verified by the existing experimental data. On this basis, the electrical energy and conversion efficiency of the fiber-constrained DEG are comprehensively analyzed under diverse system parameters, aiming to explore the feasible methods for performance improvement. Results show that both the electrical energy and conversion efficiency are enhanced by shortening the cycle period, boosting the output voltage, and increasing the time ratio of the rising segment in a cycle period. Variations of the electrical energy and conversion efficiency with the input voltage exhibit the non-monotonic behavior. In addition, at low input voltage, enlarging the maximum stretch ratio improves the EH performance, while at high input voltage, the overlarge maximum stretch ratio goes against the performance improvement. The average output power of the harvester with different lengths of rods in its displacement magnifying mechanism is also investigated. Results show increasing the rod length can improve the average output power. In addition, results can help to provide a guidance for designing a high-performance DE-based floating wave energy harvester.

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.

Ocean wave energy harvesting: Utilizing buoy float to induce dielectric elastomer deformation and electret vibration for power generation

The dielectric elastomeric polymer material, characterized by its high energy output, resilience, mechanical compliance, lightweight, damage tolerance, and low cost, demonstrates significant potential as an innovative sustainable energy converter. It seamlessly adapts to the ever-changing climatic conditions of the ocean, converting the violent impacts of wave kinetics into electrical energy. This paper proposed a viable electret and dielectric elastomer wave energy harvester to convert ocean wave energy into electricity and aims to achieve self-priming operation in the conjugate components. The output voltage from the electret also functions as the bias voltage for the dielectric elastomer, based on the intrinsic variable capacitance electric translation principle. The dielectric elastomer's deformation, equivalent to variable capacitance, successfully converted the mechanical energy from the ocean waves into electrical energy. The ocean wave energy conversion is evaluated using a system-level approach, incorporating theoretical, simulation, and experimental models. In addition, electric power generation is assessed with parameters such as output voltage, electret surface potential, and bias voltage. Essentially, the electric energy produced by the electret generator can serve as the bias voltage source for the dielectric elastomer generator, providing a self-sustaining solution for ocean wave energy harvesting. The innovative power device envisions various potential configurations for ocean-based power generation.

Ocean wave energy harvesting with high energy density and self-powered monitoring system

Constructing a ocean Internet of Things requires an essential ocean environment monitoring system. However, the widely distributed existing ocean monitoring sensors make it impractical to provide power and transmit monitored information through cables. Therefore, ocean environment monitoring systems particularly need a continuous power supply and wireless transmission capability for monitoring information. Consequently, a high-strength, environmentally multi-compatible, floatable metamaterial energy harvesting device has been designed through integrated dynamic matching optimization of materials, structures, and signal transmission. The self-powered monitoring system breaks through the limitations of cables and batteries in the ultra-low-frequency wave environment (1 to 2 Hz), enabling real-time monitoring of various ocean parameters and wirelessly transmitting the data to the cloud for post-processing. Compared with solar and wind energy in the ocean environment, the energy harvesting device based on the defective state characteristics of metamaterials achieves a high-energy density (99 W/m3). For the first time, a stable power supply for the monitoring system has been realized in various weather conditions (24 h).

A Magnetically Coupled Piezoelectric Ocean Wave Energy Harvester for Self-Powered Low-Power Appliances

The ocean contains abundant wave energy, which can be used as a new regenerative energy for power generation and provide energy for self-powered low-power appliances, realizing in situ energy utilization. Then, it can effectively promote the sustainable development strategy of the ocean and bring huge energy and social and environmental benefits. This paper proposes a magnetically coupled piezoelectric ocean wave energy harvester (MPWEH) system for wave energy harvesting. The MPWEH system includes four modules: energy harvesting, force magnification, piezoelectric power generation, and energy storage module. The energy harvesting module moves up and down in the tube body with the wave, effectively capturing and absorbing the wave energy and transforming the harvesting module’s motion into the interaction repulsive force between magnets. Then, the force magnification module amplified the magnetic force and applied it to the polarization direction of the piezoelectric ceramic to self-power the low-power appliances. This research carried out the feasibility verification experiment with the MPWEH prototype, and the results show that when the period is 3[Formula: see text]s, and the amplitude is 2[Formula: see text]m, the maximum voltage can reach 15[Formula: see text]V, and the maximum power can reach 12.85[Formula: see text]mW. Take Jiaozhou Bay Bridge as an example. The MPWEH system’s energy harvesting potential is studied, and the annual power generation of all the acquisition devices can reach 55.72[Formula: see text]kWh, which can be enough energy to supply the sensors on the cross-sea bridge.

Bidirectional Rotating Turbine Hybrid Triboelectric‐Electromagnetic Wave Energy Harvester for Marine Environment Monitoring

AbstractHydrokinetic energy, a vital renewable resource, holds promise for addressing fossil fuel shortages to ensure a sustainable future. This study proposes an efficient and stable ocean wave energy harvesting system that combines a triboelectric nanogenerator (TENG), an electromagnetic generator (EMG) with a planetary gear system, and a driving turbine. The turbine transforms the up‐and‐down motion in water into continuous, unidirectional rotational motion. An EMG device accelerated by a planetary gear system further ensures sustained output at very low frequencies (0.25 Hz) and boosts the upper limit of power generation at medium to high frequencies. Under water wave conditions with a 1 Hz frequency, the TENG component yields an output of up to 2200 V and 122 µA, while the average EMG output is 15 V and 80 mA. Remarkably, the entire system maintains a steady and uninterrupted output even at extremely low frequencies (0.25 Hz). The peak power outputs for the TENG and EMG components are 115 and 350 mW, respectively, with power densities of 32.55 and 329.78 W m−3, surpassing prior achievements. This research demonstrates self‐powered applications and provides an efficient method to amplify water wave forces, enhancing energy harvesting capabilities for practical marine environmental monitoring.

Enhanced triboelectric nanogenerators in saline environments and their applications in the ocean

Blue energy resources hold immense potential in alleviating global energy pressures, with the Triboelectric Nanogenerator (TENG) gaining attention for its unique ability to harvest ocean energy. However, applying TENG technology in the ocean still faces challenges due to its limited performance in hypersaline environments. In this work, a solid-liquid contact-based TENG is proposed for harvesting ocean wave energy. The TENG generates a significant charge output reaching up to 2.5 μC in saline water and excels in producing substantial instantaneous currents of up to 2 mA. This TENG ensures a relatively stable output in hypersaline environments. Furthermore, the TENG demonstrates the capability to degrade 98.83 % of organic dye Rhodamine B in 360 min by ionizing sodium chloride solution. Finally, a self-powered system for monitoring environmental parameters and detecting water levels is developed. This work showcases the high efficiency of TENG in harvesting energy from the ocean environment and demonstrates its immense potential for applications in marine environmental monitoring and seawater purification.

Harvesting Ocean Wave Energy via Magnetoelastic Generators for Self-Powered Hydrogen Production

Harvesting Ocean Wave Energy via Magnetoelastic Generators for Self-Powered Hydrogen Production

High-Durability Stacked Disc-Type Rolling Triboelectric Nanogenerators for Environmental Monitoring Around Charging Buoys of Unmanned Ships.

Triboelectric nanogenerator (TENG) as a means of energy harvesting can effectively harvest ocean wave energy, but the energy conversion efficiency and stability of the device during long-term operations are still problems that must be solved for TENGs. Decreasing the frictional resistance between two triboelectric material surfaces is one of the critical approaches for improving the device efficiency and durability. In this work, a novel stacked disc-type rolling triboelectric nanogenerator (SDR-TENG) is designed and fabricated for low-frequency water wave energy harvesting. After 860000 working cycles, the electrical output attenuation of the SDR-TENG basic unit is less than 5%, showing excellent device durability. Under the simulated water wave conditions, the SDR-TENG with four rolling TENG units can produce an output current of 84.4µA and an output power of 7.6mW, corresponding to an effective power density of 16.8Wm-3. This work not only proposes a strategy to effectively enhance the durability of the devices, but also provides a feasible solution for monitoring the surrounding environment of the charging buoys of unmanned ships.

Design of a multi-direction piezoelectric and electromagnetic hybrid energy harvester used for ocean wave energy harvesting

Ocean waves contain a great deal of energy, and the collection and utilization of wave energy is of great significance for sustainable development. In this paper, a multi-direction piezoelectric and electromagnetic hybrid energy harvester (PEHEH) based on magnetic coupling is proposed that can collect low frequency vibration energy from multiple directions. The proposed PEHEH combines piezoelectricity and electromagnetism through magnetic coupling to collect energy in the same excitation. The mechanical model of the PEHEH is established, and finite element simulation software COMSOL and computational fluid dynamics are used to analyze and verify the feasibility and practicability of the PEHEH structure. An experimental platform is built to test the output performance of the PEHEH. The results show that the maximum energy generated by PEHEH is 19.4 mW when the magnetic distance is 16 mm and the excitation frequency is 9 Hz. The hybrid energy harvester can light 56 light emitting diodes, which verified the feasibility of practical application. Therefore, the proposed hybrid energy harvester can effectively collect low-frequency wave energy and has a broad application prospect as a power source for low-power electronic devices.

Annular Electromagnetic Generator for Harvesting Ocean Wave Energy

To sustainably power ocean sensors by harvesting ocean wave energy, an annular electromagnetic generator (A-EMG) based on the principle of Faraday electromagnetic induction is proposed in this paper. The specific structure and working principle of the generator are introduced. The distribution of the magnetic field in the coil, the variation in the induced voltage and the influence of the coil parameters on the output were simulated by the COMSOL Multiphysics software version 6.0. At the same time, an experimental platform was built to test the output characteristics of the generator. Through a comparative study of the capacitor’s charging characteristics, the optimal connection mode between the multiple groups of coils of the generator was preliminarily verified. Finally, the six-degree-of-freedom (6-DOF) platform was used to simulate various wave motion parameters, and the feasibility of the generator for supplying power to ocean sensors was verified.

Sea State Adaptation Enhances Power Output of Triboelectric Nanogenerators for Tailored Ocean Wave Energy Harvesting

AbstractTo face the climate crisis, sustainable energy harvesting systems are critical. Triboelectric nanogenerators (TENGs) are in the spotlight for their inexpensive and non‐toxic manufacturing, allied with their excellence in harvesting low frequency vibrations. Ocean waves are a prime example of energy source in this regime, and their successful harvesting with TENGs has been widely demonstrated. However, the influence of wave characteristics on the power output of these devices has so far been overlooked. Here, the existence of a moving element that acts upon the nanogenerators is explored both with multiphysics simulations and an extensive experimental characterization under different operating conditions. It is shown how different sea states modulate the moving body velocity, and how the generator can be optimized to harvest waves with specific characteristics. In parallel, it is demonstrated that the power output is proportional to the contacting triboelectric layers velocity. Optimizing the dynamics of the moving body provides an efficient path to intentionally tune the contacting triboelectric layers velocity, and therefore improve the output of TENGs and their suitability to harvest specific sea states.

Optimal Energy Extraction of Non- Buoyant Type Wave Energy Converter Using Grey Relation Analysis

The wave energy converters involved in ocean wave energy harvesting are subjected to various natural calamities and thus obtaining the optimal energy extraction is a challenging task. It is normally noted that the energy extraction is maximum when the frequency of the ocean waves matches the natural frequency of the device. The natural frequency of the converter can be modified by tuning its dynamics, but it is intricate to perform in the ocean environment, so an alternative method should be adopted. In this work, the optimal electrical damping is performed to modify the frequency of the system to match the natural frequency of the incident wave. The grey relation analysis is carried out to find out the optimal damping value. Further, the obtained results are subjected to experimental verification and it is observed that the energy extraction is significantly improved. This approach is less complex and effective when compared with the other methods.

Wake galloping piezoelectric-electromagnetic hybrid ocean wave energy harvesting with oscillating water column

On-site continuous and energy-autonomous wireless sensor nodes are highly desirable for the sustainable monitoring of the ocean environment. In this work, a wake galloping piezoelectric-electromagnetic hybrid energy harvesting technique is developed to take off electric power from ocean wave energy. This mechanism is composed of an air chamber intake for the oscillating water column (OWC) and a piezoelectric-electromagnetic hybrid wave energy harvester in a vortex tunnel. Theoretical models and multi-physics coupled simulations are derived and established to systematically investigate the performance of the proposed harvester and the feasibility of harvesting wave energy is verified with a series of wave flume and wind vortex tunnel experiments. The results show that when the wave frequency is 0.4 Hz (the period is 2.5 s), the air pressure of the chamber is 140.12 Pa. Hence, the air is exhaled with the maximal flowing speed of 17.85 m/s in the wind vortex tunnel. For comparison, It is evaluated by the simulation model with air pressure results of 142.86 Pa and wind speed at 18.36 m/s which agree well with the theoretical values. The output voltages of the piezoelectric and electromagnetic parts are calculated with the theory and simulation as 20.34 V and 0.258 V, respectively. Furthermore, the power of the fabricated prototype piezoelectric-electromagnetic hybrid energy harvester achieves 3.76 mW and 1.33 mW, respectively, at the wind speed of 18 m/s while it is set up from the downstream of the bluff body with a windward width of 34 mm, and the space distance ratio is about 4.5. Therefore, the test and computed results provide the wave-WG-PEEH for ocean wave energy harvesting to supply the perspective of maritime low-power wireless sensors.

Industrially compatible production of customizable honeycomb-patterned poly(vinyl chloride) using food-wrapping waste for power-boosting triboelectric nanogenerator and ocean wave energy harvester

The accumulating volume of plastic waste globally, particularly from food packaging, has raised urgent concerns abour plastic pollution. Triboelectric nanogenerators (TENGs) utilizing plastic waste offer a promising solution for not only reducing plastic pollution but also minimizing the energy crisis and enabling the development of self-powered wearable electronics. However, these TENGs suffer from significant limitations, including low output performance and limited working reliability due to the use of low-grade materials. To address these issues, this study proposes a versatile approach to enhance the electrification effectiveness of poly(vinyl chloride) (PVC) waste by imprinting a customizable honeycomb structure on its surface. The proposed method is cost-effective, environmentally friendly, and time-efficient, enabling the production of a uniform porous structure on large PVC film surfaces (e.g., 12 × 10 cm2). This approach facilitates the recycling of a significant amount of PVC plastic waste in the environment without emitting any toxic by-products, unlike other thermal treatments. The honeycomb structure is imprinted on the raw aluminum-contained multilayered packages, serving as both the electrode and frictional surface. The TENG, assembled with negatively charged structured PVC and the aluminum counterpart, demonstrates remarkable performance, generating an open-circuit voltage of 340 V and an average power density of 2.8 W m−2. These values represent an enhancement of approximately 2.7 times and 4 times, respectively, compared to flat PVC. Furthermore, the waste-based TENG exhibits exceptional durability and reliability, with smooth operation even after 20,000 contact-separation cycles. Due to the excellent water repellency of the honeycomb structure, the hc-PVC shows particular promise for applications in ocean wave energy harvesting and powering wastewater monitoring sensors, extending its potential beyond conventional usage.