Tidal Power Generation Research Articles

FVCOM-CFD model-based study of hydraulic turbine arrays in Mount Putuo tidal current energy test site

In recent years, China has started to vigorously promote the research of tidal energy power generation technology; and during site testing of tidal energy converters, the distributed tidal energy converters will produce a certain effect on the flow field of the sea area. In this paper, on the basis of a tidal current energy test site established in the sea area between Mount Putuo Island and Hulu Island in Zhoushan city, Zhejiang Province, a far-field mathematical model of a three-dimensional FVCOM model was established, and in conjunction with the TSE evaluation method optimized by incorporating flow characteristic parameters. Compared to traditional assessment methods, the research aims to mitigate the influence of shallow water high-flow-speed regions and complex terrain in the test site area. Use the analysis results as CFD input conditions to perform pseudo-instantaneous numerical simulation to investigate the impact of different deployment angles on the power characteristics of hydraulic turbines, thereby providing ideas for optimizing the arrayed arrangements of tidal energy converters.

Optimal site selection and potential power assessment for tidal power generation in the Seto Inland Sea, Japan, based on high-resolution ocean modelling and multicriteria analysis

In response to Japan's ambitious pursuit of carbon neutrality by 2050, this paper investigates the potential for tidal power generation in the Seto Inland Sea (SIS), Japan, utilising high-resolution ocean modelling and an analytic hierarchy process (AHP) combined with GIS-based spatial analysis. The analysis incorporates a 100 m resolution tidal current and water depth layers from the ocean model. The criteria used for evaluation were divided into main criteria, namely, proximity to existing infrastructure, wave height, and shipping density, and subcriteria, namely, distance from ports, power stations, highly populated areas, and coastlines. The identified optimal locations include the Naruto Strait, Akashi Strait, Matsushima Island, Hanaguri Strait, Funaori Strait, Taizaki Island, Kurushima Strait, Obatake Strait, and Tsuwaji Strait. With a focused analysis of the Obatake Strait in Yamaguchi Prefecture, analytical assessments of potential tidal power were conducted by considering two tidal turbines, Openhydro and Voith. The results indicate a power supply for approximately 100,000 households and a reduction of approximately 198,000 t-CO2 per year in the most optimistic scenario. In a less optimistic scenario, with the installation of only 10% of the maximum capacity, a power supply for approximately 10,000 households and a reduction of approximately 19,800 t-CO2 per year are observed. As Japan targets carbon neutrality by 2050, this research offers vital and practical insights for policymakers, energy planners, and environmentalists, identifying the Seto Inland Sea as a strategic area for tidal power development, aligning with Japan's commitment to a sustainable and resilient energy landscape.

Research on Control Strategy of PMSG-PWM Power Generation System with Tidal Energy

Aiming at the characteristics of machine-side output instability and the wide-range variation in the tidal energy PMSG-PWM power generation system, we propose a control scheme with a high anti-interference capability applied to the PWM rectifier. The outer voltage loop adopts sliding mode control (SMC) with the variable exponential convergence law based on expanded state observer (ESO). By compensating the perturbation observation value into the sliding mode controller in advance, it improves the robustness and response speed of the system and suppresses the direct current (DC)-side voltage jitter phenomenon. The current inner loop combines model prediction (MP) with direct power control (DPC). By introducing time-delay compensation, it improves the control accuracy, reduces the machine-side harmonic content, and enables the system to maintain unit power factor operation despite external disturbances. Simulation and experiment results show that, under the wide range of PMSG output, the PMSG-PWM power generation system adopting the “ESO_SMC+MDPDC” scheme has a fast dynamic regulation of DC output voltage, obvious vibration suppression effect, low harmonic content of the current on the PMSG side, and fast current tracking speed, which verify the feasibility of applying this system to the field of tidal energy generation.

DESIGN AND DEVELOPMENT OF TIDAL ENERGY GENERATION SYSTEM

Sustainable energy generation is becoming increasingly important due to the expected limitations in current energy resources and to reduce pollution. Wave energy generation has seen significant development in recent years. Renewable power generation has become increasingly vital in addressing global energy challenges and mitigating the impacts of climate change. Various forms of renewable energy sources, such as solar, wind, and hydroelectric power, have gained prominence in the pursuit of sustainable energy solutions. Among these, tidal power stands out as a promising option due to its predictability and minimal environmental impact. This abstract explores the significance of renewable power generation and introduces the concept of tidal power generation, focusing on the innovative technology of tidal floater turbines. It delves into their construction and operational principles, illustrating their potential as a sustainable energy source. Ultimately, this abstract underscores the growing importance of harnessing tidal power as a clean and reliable source of electricity for the future. Tidal floater turbines represent an innovative system for harnessing the energy potential of ocean tides. These turbines are strategically constructed on the surface of the sea, where the dynamic ebb and flow of tides generate kinetic energy. The turbines consist of underwater rotors connected to electrical generators, which are capable of converting the mechanical energy of tidal currents into electricity. The operation of tidal floater turbines is driven by the predictable and consistent nature of tidal cycles, making them a dependable source of renewable energy. By exploiting the immense power of the ocean's tides, these turbines offer a sustainable solution for meeting the world's growing energy demands. The result from wave simulator using a real wave profile captured at a location in UK using an ultra sound system it was seen that ±0.8m wave at 10sec time period, produce a condition power output of approximate 22KW at optimum load condition for the tested 3 phase 44KW permanent magnet generator type STK500 the result indicate that this new technology could provide an effective and low cost method of generating electricity from waves. In conclusion, the utilization of tidal power generation, specifically through the innovative technology of tidal floater turbines, holds significant promise in the realm of renewable energy. As society seeks to reduce its carbon footprint and transition towards cleaner energy sources, the predictability and consistency of tidal power make it an attractive option. Moreover, the construction of these turbines on the sea's surface minimizes ecological disruptions, further emphasizing their environmental sustainability. With ongoing research and development, tidal power generation has the potential to play a pivotal role in our quest for a greener and more sustainable energy future.

Study on the influence of ship waves on the dynamic response of floating tidal current power generation device

To study the influence of ship traveling waves on the hydrodynamic performance between the carrier platform and the turbine, the computational fluid dynamics method and the DFBI motion module of STAR CCM+ software were adopted. Under the condition of the coupling of the ship traveling wave and wave current generated at different speeds, the overall motion response of the power plant is simulated. What’s more, the influence of different wave conditions on the heave, pitch, and roll of the carrier platform and the energy efficiency of the turbine is analyzed. The results show that the ship speed has little effect on the carrier heave motion, but the maximum value of the carrier pitch motion increases with the increase in the ship speed. The value of turbine energy acquisition efficiency always decreases with decreasing lateral spacing and increases with decreasing speed. This paper has a certain reference value for the engineering application of floating tidal current power generation equipment.

Research on the environmental benefits of marine tidal energy and its impact on regional economic structure

Tidal power generation, being one of the earliest and largest developed new energy technologies, has evolved into a mature and increasingly competitive source of energy. This article delves into the evaluation of tidal energy's socioeconomic impact, establishing a connection between its environmental benefits and regional economic development. The focus is on marine economic efficiency, and the super-efficiency DEA model is employed to gauge this efficiency. The study conducts a thorough analysis of the green ocean economic efficiency in three major regions, introducing the Malmquist efficiency index for a comprehensive understanding of changing trends. Utilizing an economic effect model, the research explores the contribution of tidal energy development to regional economic growth, delving into industry-related effects. Through these analyses, we aim to provide a clearer and more comprehensive insight into the positive influence of tidal energy on regional socioeconomics. This understanding is pivotal for guiding sustainable tidal energy development and formulating relevant policies.

Discussion on low-carbon energy supply and scour protection technology for cross-sea bridges combined with tidal current energy

In the context of achieving carbon peak and carbon neutrality, the construction and maintenance of transportation infrastructure should also comply with the requirements of green and low-carbon development. There are many long-span cross-sea bridges in Zhejiang Province, which consume large amounts of electricity for lighting, dehumidification, and anticorrosion, etc., and the energy required usually relies on external energy transfer, which is costly and intermediate losses are high. Tidal current energy, which is the kinetic energy generated during ebb and flood tides, is abundant along the coast of Zhejiang Province, mainly concentrated in Hangzhou Bay and Zhoushan Islands, which is also a dense area of sea-spanning bridges, and the foundation of sea-spanning bridges often suffers from severe scouring to the strong tidal current action. This paper discusses two forms of joint development of tidal current power generators and cross-sea bridges, analyses the advantages and disadvantages as well as the feasibility of each scheme, and gives suggestions for subsequent development.

Design and Optimization of Coaxial Magnetic Gear With Double-Layer PMs and Spoke Structure for Tidal Power Generation

A coaxial magnetic gear (CMG) with double-layer permanent magnets (PMs) and Spoke structure is proposed to replace the mechanical gearbox in tidal power generation system. For the inner rotor PMs, the distributions of PMs are the spoke structure with different sizes, and the magnetization direction is Halbach array. The outer rotor PMs have two layers, one is Halbach array, and the other is radial magnetization. According to the sensitivity of parameters, the response surface method and multiobjective genetic algorithm are used for optimization analysis to determine the optimal structural dimension parameters of CMG. A CMG topology with 4 inner poles and 17 outer poles is established. Compared with the conventional CMG, the output torque of the proposed CMG is increased by 33.42%. Finally, a prototype was made and a test platform was built. The experimental results show that the transmission ratio of the proposed model is consistent with the theoretical value, the no-load loss is relatively small, and the efficiency is high.

A novel two-layer nested optimization method for a zero-carbon island integrated energy system, incorporating tidal current power generation

A novel two-layer nested optimization method for a zero-carbon island integrated energy system, incorporating tidal current power generation

A numerical approach to the treatment of submerged water exchange processes through the sluice gates of a tidal power plant

Tidal power generation is a sustainable technology for electricity generation and is regulated by water exchange through the hydraulic structures of the tidal power plant (TPP). In the numerical modeling of tidal power generation, the water exchange rate through the sluice gate has previously been estimated based on the water level difference and was input for the entire water column as a two-dimensional boundary condition. However, in this study, a three-dimensional simulation method for the water exchange rate, including submerged hydrological conditions and the momentum of the surrounding flow, was applied. A new numerical approach to water exchange was applied in the idealized tests, and the subsequent model results showed high reproducibility for the orifice velocity field results from laboratory experiments. To verify the hydrodynamics with the actual region, a numerical model was configured for the Sihwa TPP and evaluated through comparison with observation data. The model not only accurately reproduced the temporal variability of the current velocity results, but also reliably reproduced the spatiotemporal flow patterns related to the jet-like and anticlockwise rotating flows. Therefore, to explain the complex, spatiotemporal, and asymmetric flow structure around TPP, high-resolution grid-based 3D modeling technology associated with the submerged sluice gate is needed.

Experimental Optimization Environment for Developing an Intracycle Pitch Control in Cross Flow Turbines

Cross-flow tidal turbines also known as vertical-axis turbines have not reached the efficiency as it is usual found for horizontal-axis turbines. This can be mainly accounted to the intensive development effort dedicated to the latter in the past 30 years in the area of wind energy. Less attention has been given to cross-flow turbines as they present mechanical cyclic loads that detriment their durability. Nevertheless, there is great potential for their employment in tidal energy exploitation as they are intrinsically independent from the flow direction and have a higher power output per area in farm installation. For this reason the research for cross-flow turbines have regain impulse.
 Among various approaches to improve their hydrodynamic characteristics found in the literature, the intracycle pitch control is one of the most promising one. It consists in actively pitching each blade as function of the azimuth angle.
 The present paper will introduce the overall experimental environment and methods for developing an optimal intracycle control for cross-flow turbines in tidal power generation. This is the main component of project OPTIDE at Otto-von-Guericke-University Magdeburg, Germany in cooperation with the LEGI at University Grenoble-Alpes, France and the University of Applied Sciences Magdeburg-Stendal.
 The experimental system consists of a turbine flume model equipped with a speed controlled generator. The three bladed turbine model has independent controlled pitch actuators embedded in each blade and a force sensing system in one of the blade holding arms. Local high-dynamic systems allow to control the speed of the generator and the pitch position as a function of the rotational angle of the runner i.e. pitch trajectory.
 A superimposed governing system which automates the experiment has been implemented. This allows to perform an optimization process with the experiment in the loop. Evolutionary algorithms are employed to solve the two objectives of the optimization: (1) Maximizing the efficiency by (2) minimizing the alternating structural loads on the runner. These kind of problems are usually solved with numerical simulations using finite element method (FEM) and computational fluid dynamics (CFD). However, this commonly comes with very high computational efforts and uncertainty. For this reason in our approach simulations are replaced by an experimental optimization technique.
 The optimization cycle implemented in the superimposed governing system chooses a set of individuals (pitch trajectories) for each generation on base of the genetic algorithm. Each pitch trajectory is performed sequentially while power output and loads are measured. This allows to evaluate each individual in about one minute. The best individuals are then the base for the offspring of the new generation. Cross-over from best performing parents and subsequent mutation ensure both, convergence and a thorough exploration of the entire design space.
 It is expected that this method will fast and reliably find the optimal pitch trajectories under various conditions. Selected cases will be analysed in detail by means of particle-image velocimetry (PIV) with synchronized force and torque measurements to research the underlying hydrodynamic mechanisms and the effects of the flow control performed by the pitching motion.

A method for the growth inhibition of biofouling in Sihwa Tidal Power Plant

Many facilities in contact with seawater are constantly affected by marine biofouling.In particular, marine biofouling cause many problems, such as reducing efficiency of water turbine, interfering with water barrier by stop log, and generating harmful gas (ammonia) due to the death of fouling organisms during Overhaul.For this reason, Sihwa Tidal Power Plant has been researching various fouling organism reduction technologies for the past 8 years, through this, we have increased tidal power generation and operated and maintained tidal power generation facilities smoothly.This paper presents an analysis of marine biofouling reduction technology of Sihwa Tidal Power Plant. It shows the status and characteristics of fouling organisms, problems and impacts, improvement plans and effects of the Sihwa Tidal Power Plant.

A robust planning model for offshore microgrid considering tidal power and desalination

Increasing attention has been paid to resources on islands, thus microgrids on islands need to be invested. Different from onshore microgrids, offshore microgrids (OM) are usually abundant in ocean renewable energy (ORE), such as offshore wind, tidal power generation (TPG), etc. Moreover, some special loads such as seawater desalination unit (SDU) should be included. In this sense, this paper proposes a planning method for OM to minimize the investment cost while the ORE’s fluctuation could be accommodated with robustness. First, a deterministic planning model (DPM) is formulated for the OM with TPG and SDU. A robust planning model (RPM) is then developed considering the uncertainties from both TPG and load demand. The Column-and-constraint generation (C&CG) algorithm is then employed to solve the RPM, producing planning results for the OM that is robust against the worst scenario. Results of the case studies show that the investment and operation decisions of the proposed model are robust, and TPG shows good complementarity with the other RESs.

Design and performance analysis of a passive rotatable deflector diversion tail for tidal current power generation hydrokinetic turbines

In the present study, a deflector that can passively rotate is designed for use on a hydrokinetic turbine that generates power from tidal currents. This deflector is capable of self-adjusting its position with changes in the water flow, so that the hydrokinetic turbine can generate maximum power at both high and low tides. The purpose of this study is to maximize the output power of a hydrokinetic turbine by improving the geometry of the deflector and the diversion tail. The rotation of both the turbine and the deflector are simulated with finite element analysis software. In addition, the accuracy of the simulation results is verified through experimental tests. The improved design of the deflector and the diversion tail is considered in terms of the parameters, including the deflector reduction angle, the gap between the deflector and the turbine, and the height of the diversion tail. The geometrical design of the deflector and the diversion tail is compared to a turbine without the deflector and to another turbine with the original deflector over the entire operating range using CFD simulations. Without the deflector, the maximum power coefficient of the turbine was 0.0979 at a tip-speed ratio of 0.4, whereas the maximum power coefficient of the turbine was 0.306 at a tip speed ratio of 0.57 when using the improved deflector. The results indicate that, after adding the improved deflector, the power coefficient of the turbine was 3.13 times greater compared with the turbine without the deflector and 18% greater compared with the turbine equipped with the original deflector.

A comparison of the power potential for surface- and seabed-deployed tidal turbines in the San Juan Archipelago, Salish Sea, WA

The San Juan archipelago lies along the axis of tidal movement between Straits of Juan de Fuca and Strait of Georgia in the Salish Sea. The amplitude of the tidal exchange produces significant tidal currents between the islands, as well as in Rosario Strait to the east and Haro Strait to the west. These currents are of interest as a future source of electrical power generation, given the archipelago’s dependence on electricity supply by a subsea cable from the United States mainland. Here, we evaluate the tidal current energy potential in this region through a re-analysis of measurements collected by the National Ocean Service (NOS) and a high-resolution numerical model. Given the considerable variations in water depth and vertical velocity profiles across candidate tidal energy sites, we consider the trade-offs between tidal turbines deployed from a floating platform and those anchored to the seabed. Measurement re-analysis indicates several locations that could support tidal current power generation by MW-scale turbines with an acceptable balance between turbine size, rated power, and capacity factor. Even for relatively large (30 m) turbine diameters, surface-deployed turbines would be expected to produce up to 30 % more electricity than the same turbine deployed near the seabed due to vertical shear, with this difference increasing for smaller diameter turbines. As anticipated for sparse measurements, the regional simulation identifies several locations with power generation potential more than twice as high as locations in the measurement re-analysis. These sites were either not surveyed or excluded due to data quality issues. A benchmark comparison at the measurement locations with the highest power generation potential shows relatively good model fidelity, though time-average power density disagreements of ± 50 % persist throughout the water column. In addition to the case study, we also treat three general considerations for measurement data: (1) the accuracy of energy generation estimates from hub height speed relative to rotor-averaged power density, (2) the feasibility of extrapolating profiles towards the surface and seabed, and (3) trends in energy generation with rotor size and position in the water column. Overall, these results demonstrate that models and measurements can be used in a complementary manner for tidal energy site assessment and that tidal currents could be an important source of electricity generation in the San Juan archipelago.

Modeling and simulation of power quality detection for tidal current power generation based on HHT

On the basis of summarizing the characteristics of tidal current power generation and power quality analysis methods at home and abroad, this paper comprehensively analyzes the power quality problems existing in tidal current power generation, and Hilbert–Huang transform (HHT) is finally applied to detect and analyze the issues. Using MATLAB to establish the simulation model, and the analysis algorithm of power quality in frequency domain and time domain is focused. The simulation results of single disturbances and some mixed disturbances show that this method has good adaptability to the non-stationary and multi-disturbance characteristics of tidal power generation.

A State-of-the-Art Review of Structural Testing of Tidal Turbine Blades

Over the last two decades, the tidal energy industry has laid the groundwork for creating commercially viable tidal power generation projects to strengthen sustainable energy policies around the world. At the end of 2021, the cumulative installation of tidal stream technology that has been deployed in Europe reached 30.2 MW, where the majority of the installations are by small and medium-sized companies. Due to a growing demand among investors related to the global tidal energy industry, the reliability and safety of operational-stage tidal energy systems’ components are becoming increasingly important. In this context, companies, universities and research institutes are focusing on conducting large- and small-scale tests of tidal turbine elements to validate their projected design life, and major attention is being given to assessing the structural integrity of turbine blades. This review paper focuses on structural tests that have been reported for axial flow tidal turbine blades manufactured using composite materials around the world, highlighting the testing standards, equipment and instrumentation required. Overall, this review article discusses the state of the art in the structural testing of tidal turbine blades. In addition, it highlights the global concerns and research gaps to ensure the long-term sustainability of axial flow tidal turbine blades. In addition, the information contained in this article will be useful for formulating a smooth and reliable mechanism to enhance the evaluation process of the structural properties of tidal turbine blades in the future.

Simulation and study of maximum power point tracking for rim-driven tidal current energy power generation systems

This paper presents a maximum power point tracking (MPPT) control algorithm based on an intelligent reinforcement learning. The proposed model-free Q-learning algorithm realizes the online learning of the control algorithm of the tidal power generation system by updating the action values stored in the Q-table. By learning the optimal rotor speed-output power curve, the algorithm fits the optimal generator curve and applies the optimal Pe−ωr curve to the optimal control method of the tidal power generation systems.

Analysis and Research of China’s Marine Renewable Energy Standards

China has already had relatively mature marine renewable energy utilization, among which tidal current energy power generation has achieved grid connection, and wave energy power generation has been commercialized. However, in spite of progress in the marine renewable energy utilization, China’s marine renewable energy standard system still needs improvement as there is still no marine energy standards for some subsystems, which can’t provide effective support for the innovation of marine renewable energy and the development of the industry. This paper explains the status quo of marine renewable energy standards both at home and abroad, analyzes China’s current problems in the development of marine energy standards, and offers recommendations for future development.

Marine Power Generation Methods and Future Developments

With the continuous advancement of science and technology, ocean energy continues to develop because of its renewable, clean and stable advantages. This paper mainly studies the issue of ocean energy power generation, focusing on tidal energy power generation, wave energy power generation and ocean current power generation. The practical application of tidal energy power generation, and the negative and positive impacts of clean energy such as tidal energy on the marine environment after application, various methods and advantages and disadvantages of ocean current/ocean current power generation are described, and the explanation of many instruments in these power generation methods. For instance, the equipment used in tidal energy, wave energy and ocean current power generation are oscillating water column wave energy converter, mechanical wave energy generation, the diffuser-augmented floating hydro turbine, Darrieus deep-sea vertical axis turbine and so on. At last, from the actual cases of China's use of clean energy such as tidal energy and wave energy to generate electricity, we analyzed the future development trend of ocean energy and concluded that ocean energy will be vigorously developed in the future to replace some fossil energy.