Tidal Power System Research Articles

A Novel Hybrid MPPT Controller for PEMFC Fed High Step-Up Single Switch DC-DC Converter

At present, there are different types of Renewable Energy Resources (RESs) available in nature which are wind, tidal, fuel cell, and solar. The wind, tidal, and solar power systems give discontinuous power supply which is not suitable for the present automotive systems. Here, the Proton Exchange Membrane Fuel Stack (PEMFS) is used for supplying the power to the electrical vehicle systems. The features of fuel stack networks are very quick static response, plus low atmospheric pollution. Also, this type of power supply system consists of high flexibility and more reliability. However, the fuel stack drawback is a nonlinear power supply nature. As a result, the functioning point of the fuel stack varies from one position to another position on the V-I curve of the fuel stack. Here, the first objective of the work is the development of the Grey Wolf Optimization Technique (GWOT) involving a Fuzzy Logic Controller (FLC) for finding the Maximum Power Point (MPP) of the fuel stack. This hybrid GWOT-FLC controller stabilizes the source power under various operating temperature conditions of the fuel stack. However, the fuel stack supplies very little output voltage which is improved by introducing the Single Switch Universal Supply Voltage Boost Converter (SSUSVBC) in the second objective. The features of this proposed DC-DC converter are fewer voltage distortions of the fuel stack output voltage, high voltage conversion ratio, and low-level voltage stress on switches. The fuel stack integrated SSUSVBC is analyzed by selecting the MATLAB/Simulink window. Also, the proposed DC-DC converter is tested by utilizing the programmable DC source.

Effect of Sea Level Rise and Access Channel Deepening on Future Tidal Power Plants in Buenaventura Colombia

The evolution of tidal stream turbines is increasing the feasibility of future tidal plants in shallow depth areas with mid-tidal ranges (<5 m). However, extreme events such as changes in bathymetry due to the access channel deepening of coastal ports and sea level rise modify hydrodynamics and might affect the infrastructure and energy production of tidal energy converters. This research focused on Buenaventura Bay to analyze the effect of these extreme events on marine currents through calibrated-validated numerical modeling. Several monitored points were analyzed, and the results highlighted that the bay has potential for implementing tidal stream turbines because of the reported velocities between 0.25 and 2 m/s. The sea level rise increased 11.39% and access channel deepening reduced by 17.12% the velocity currents of the bay, respectively. These findings convert Buenaventura Bay to a candidate for implementing third generation tidal stream turbines and motivate future research for implementing tidal power systems in crucial areas such as the Colombian Pacific, where communities face restrictions in accessing affordable and clean energy.

The Development of Tidal Power System Can be Installed in Existing Dykes -The Open Channel Experimental Verification

As problems such as difficulties in securing stable energy resources and global warming due to the emission of greenhouse gases due to the use of fossil fuels have emerged, interest in the development of renewable energy is increasing. Since the tidal phenomenon has a regularity that occurs regularly with a certain period, it is possible to predict accurately in advance, which has a advantage in terms of energy recovery. Therefore, various methods have been devised to utilize the tide as an energy source. Tidal power using barrages is a representative method that is widely operated, but the promotion of tidal power generation projects is being delayed or stopped due to the decrease in the level of water in the tidal basin, changes in water quality and in the ecosystem. In this study, a field experiment was conducted to develop and verify the performance of a tidal power device applicable to sea areas where dykes are already installed. As a result of carrying out four cases of experiments using two water tanks, pipe lines, open channels, weirs, and water turbine and generator, the possibility of developing a power generation system capable of 10 kW output or more and 60% efficiency or more was confirmed. These research results can be used for small-scale tidal power by utilizing the existing dykes.

Modeling and Power Optimization Control of Tidal Energy Systems

As interest in emergency power has increased, research on engine generators has been actively conducted. Permanent magnet synchronous generators (PMSGs) are suitable for small-capacity engine generators because they have higher efficiency and faster response than other motors. In this paper, the static and dynamic characteristics of the tidal turbine have been modeled and implemented experimentally. The rotational speed of the PMSG is regulated to extract the generator maximum power at a variable tidal velocity using the conventional optimum tip-speed ratio method. has been implemented to the proposed tidal power system since it is a simple method. The performance of the PMSG in the tidal power system has been investigated at different tidal speeds. The experimental results have validated the efficiency of the proposed controller to extract the maximum power point.

Small scale standalone solar and tidal hybrid power system in isolated area

The source of electricity supply in isolated areas is commonly from diesel or other fossil fuel-based generation systems. However, the increasing cost and harmful emissions of these fuels have led researchers to seek alternative solutions in providing electricity. Hence, harnessing renewable resources can be a favourable solution in lowering the dependency on fossil fuels. The Strait of Malacca is blessed with tidal current energy, a research was conducted to design a hybrid renewable energy system (HRES) that consists of tidal current and solar energy as its sources along with backup power such as generators to support the electrical demand of a lighthouse. A simulation method is used to determine and compare the optimal configuration of the HRES with the diesel generator-based system. An evaluation of all possible scenarios of standalone systems was carried out by considering the amount of fuel consumption and pollutant emittance, capacity shortage, excess electricity production, unmet energy and renewable fraction parameters of each system scenario. From the findings, the hybrid energy system of Scenario A that consists of tidal turbines, PVs, generator, battery, and converter produces better results where the diesel fuel consumption can be reduced up to 84% in comparison with the standalone generator-based system.

Research on Reliability of Grid Connected Photovoltaic Renewable Generation System

Renewable energy sources are increasingly being implemented in power systems to curb global warming and improve generation adequacy. These renewable sources include Hydro, wind, tidal, and solar power systems. Since Pakistan experiences decent solar irradiation throughout the year, the most viable renewable energy option is photovoltaic generation. Before solar systems are implemented, the proposed design is first simulated using design software such as MATLAB-Simulink to correct and adjust parameters to attain the DC voltage and current through the irradiation and environment temperature. Reliability studies and analysis are performed on the simulated systems to ascertain the success and long life before the system components’ failure. In this thesis, the grid-connected PV system’s reliability model established based on the reliability block diagram method using the MIL-HDBK-217F handbook. The handbook provides the methodology of calculating failure rates of specific physical electronics operations. The mean time to failure (MTTF) and Mean time to repair (MTTR) of the system is calculated from the overall system reliability. Photovoltaic power output varies greatly, and it is dependent on solar irradiation and temperature, resulting in intermittent and variable energy production. All of these considerations have a significant effect on the entire system adequacy of the power generation system. This study uses a probabilistic analytical methodology to develop comprehensive reliability models of grid-connected Photovoltaic generation systems.

Intelligent Energy-Based Modified Super Twisting Algorithm and Factional Order PID Control for Performance Improvement of PMSG Dedicated to Tidal Power System

The majority of marine current conversion technologies are based on permanent magnet synchronous generators (PMSG) due to its numerous advantages such as high-power density, low cost, and favorable electricity production. However, nonlinear properties of the generator and parameter uncertainties, makes the controller design more than a simple challenge. This paper proposes a new adaptive passivity-based (PB) modified super twisting algorithm (PBSTA) for control performance improvement (low tracing errors, fast convergence response, robustness) of a PMSG based marine current energy conversion system under swell effect and parameter uncertainties. The proposed approach combines a new PB current control (PBCC) with a new adaptive modified super twisting algorithm through a fuzzy logic supervisor. A new adaptive fractional order PID (FO-PID) controller is introduced to design the desired dynamics of the system. The main contributions and motivation of this work include the extraction of maximum power from the tidal current, integrating it to the grid and making the closed loop system passive. This is possible by reshaping system energy and introducing a damping term that compensates the nonlinear terms by a damped way and not by cancellation. Two steps are needed to design the proposed controller: the first step includes the derivation of reference current based on the reference torque using adaptive FO-PID. In the second step, the overall control law is computed by the proposed PBSTA. The exponential stability and error convergence of the proposed controller are analytically proven. The developed controller is tested under parameter variations and it is compared to benchmark nonlinear control methods such as sliding mode. Extensive investigation under MATLAB/Simulink, demonstrates clearly that the proposed technique provides higher efficiency and robustness over the benchmark nonlinear control methods.

On the potential of linked-basin tidal power plants: An operational and coastal modelling assessment

Single-basin tidal range power plants have the advantage of predictable energy outputs, but feature non-generation periods in every tidal cycle. Linked-basin tidal power systems can reduce this variability and consistently generate power. However, as a concept the latter are under-studied with limited information on their performance relative to single-basin designs. In addressing this, we outline the basic principles of linked-basin power plant operation and report results from their numerical simulation. Tidal range energy operational models are applied to gauge their capabilities relative to conventional, single-basin tidal power plants. A coastal ocean model (Thetis) is then refined with linked-basin modelling capabilities. Simulations demonstrate that linked-basin systems can reduce non-generation periods at the expense of the extractable energy output relative to conventional tidal lagoons and barrages. As an example, a hypothetical case is considered for a site in the Severn Estuary, UK. The linked-basin system is seen to generate energy 80–100% of the time over a spring-neap cycle, but harnesses at best ≈ 30% of the energy of an equivalent-area single-basin design.

Temporal Evolution Assessment of Dynamic Tidal Power Including Turbine Effects

Dai, P.; Zhang, J., and Xiao, L., 2020. Temporal evolution assessment of dynamic tidal power including turbine effects. Journal of Coastal Research, 36(5), 1050–1058. Coconut Creek (Florida), ISSN 0749-0208.The dynamic tidal power system adopts a coast perpendicular dike in capturing tidal potential energy and is basin free as opposed to the conventional tidal barrage system. Since it is important for the developers to have detailed information of the power output characteristics prior to implementation, the temporal evolution of the power output has been studied to improve the understanding of the dynamic tidal power resource using a two-dimensional hydrodynamic model. The model accurately simulates the tidal motion characteristic of Chinese marginal seas. As an essential input for the temporal power estimation, the turbine operation is taken into account for this study, while the watertight dike has often been considered in previous feasibility studies. The results show that the monthly average power output increases, reaches a maximum, and then decreases with an increase in the number of turbines. The temporal evolution of power is featured by strong semidiurnal intermittency due to the semidiurnal tide. The peak power is recorded as 2.81 GW during spring tide, when 8% of the dike is opened for turbines. The magnitude reduces in both the middle and neap tide stages. Four peaks in the monthly average hourly power variation histogram were picked up, with much more homogeneity as compared with the power series during any specific tidal stage. Structurally, the T-branch added to the seaward tip of the I-shaped system is called the T end and forms the T-shaped system. It is proposed that this T-shaped system leads to an increase in production. The T end harvests substantially greater M2 energy than K1 energy near the seaward end of the system. The concentration of M2 energy contributes to the improvement in power production.

Tidal current and tidal energy changes imposed by a dynamic tidal power system in the Taiwan Strait, China

The Taiwan Strait has recently been proposed as a promising site for dynamic tidal power systems because of its shallow depth and strong tides. Dynamic tidal power is a new concept for extracting tidal potential energy in which a coast-perpendicular dike is used to create water head and generate electricity via turbines inserted in the dike. Before starting such a project, the potential power output and hydrodynamic impacts of the dike must be assessed. In this study, a two-dimensional numerical model based on the Delft3D-FLOW module is established to simulate tides in China. A dike module is developed to account for turbine processes and estimate power output by integrating a special algorithm into the model. The domain decomposition technique is used to divide the computational zone into two subdomains with grid refinement near the dike. The hydrodynamic processes predicted by the model, both with and without the proposed construction, are examined in detail, including tidal currents and tidal energy flux. The predicted time-averaged power yields with various opening ratios are presented. The results show that time-averaged power yield peaks at an 8% opening ratio. For semidiurnal tides, the flow velocity increases in front of the head of the dike and decreases on either side. For diurnal tides, these changes are complicated by the oblique incidence of tidal currents with respect to the dike as well as by bathymetric features. The dike itself blocks the propagation of tidal energy flux.

Hydrodynamic Investigation of Combinations of Double and Triple Dynamic Tidal Power Systems

As an efficient and environmental-friendly way to exploit the power of tides in the coast zone, dynamic tidal power (DTP) system interests the researchers around the world. While it is known that the Yellow Sea and Bohai Sea along Chinese coastline store a notable amount of dynamic tidal power, the construction of DTP dams in this area has been studied. Based on previous researches, combinations and collaborations of double and triple dynamic tidal power dams are investigated. The efficiency of each dam may fluctuate slightly when two or three dams work together and the entire system may work well especially with the presence of the dam at the cape of Liaoning Peninsula.

Reinvestigation of the Dynamic Tidal Power Dams and their Influences on Hydrodynamic Environment

Dynamic tidal power (DTP) system is known as an efficient method to exploit the tidal power. Large storage of tidal power in the Yellow Sea and the Bohai Sea along the Chinese coastline is revealed by previous studies. In the consideration of the local environment, combination of smaller DTP dams located at three attractive positions in this area is investigated. Their efficiency is compared with that of larger DTP dams working singly. The influences of the triple smaller dams are also discussed together with those of the single larger dams placed at the same locations.

Applicability of a new tidal power system with reduced environmental impact

Applicability of a new tidal power system with reduced environmental impact

Predictions for Dynamic Tidal Power and Associated Local Hydrodynamic Impact in the Taiwan Strait, China

ABSTRACT Dai, P.; Zhang, J., and Zheng, J., 2017. Predictions for dynamic tidal power and associated local hydrodynamic impact in the Taiwan Strait, China. Dynamic tidal power systems are a new alternative to tidal barrage systems for extracting tidal potential energy. In these systems, a dike perpendicular to the coast is used to create a water head, which is then converted into electricity. In this study, a mathematical model was developed using Delft3D FLOW to evaluate the power output and hydrodynamic consequences of a dynamic tidal power system in the Taiwan Strait. The model is composed of a coarse-resolution subdomain and a fine-resolution subdomain, and a domain decomposition technique was adopted to simulate flow through the interfaces of these subdomains. In the simulation, the mean power reached its maximum (0.89 GW) at a dike open ratio of 8%. The power system strongly affected the M2 tide in the local region. Overall, the amplitude of the M2 tide increased on the NE side of the system and dec...

Optimal Design of a MW Class SCSG for a Tidal Current Power Generation System

A superconducting synchronous generator (SCSG) can be expected to decrease the size and weight compared to conventional tidal current generators. This paper proposes an optimal design of a 2 MW class SCSG for a tidal current power generation system. The proposed optimal design of the SCSG will reduce the length of the high-temperature superconducting wire as well as the weight and volume of the SCSG. The 3D finite element method is used to analyze the magnetic field distribution. The optimized 2 MW SCSG is compared with a 2 MW conventional generator. As the optimized SCSG is more compact and lighter than a conventional generator, it will be efficiently applied to practical tidal power systems.

Hydrodynamic study of phase-shift tidal power system with Y-shaped dams

Phase-shift tidal power system with a dam deployed perpendicularly to a coastline in the sea is considered. The tidal power is extracted from water level difference on both sides of the dam, which originates from different propagation path of the tidal wave and the phase shift in water levels. This study focuses on hydrodynamic characteristics of a Y-shaped dam under the action of the tidal waves and explores the effects of the dam parameters on the phase shift of the tidal waves on both sides of a main dam and water head. A two-dimensional model is used to simulate tidal flows in the Taiwan Strait and Qiongzhou Strait. The model is validated by comparing the numerical results with previous studies and available measurements. The influence of the angle between the main dam and the branch dam, branch dam length, and dam types on phase difference in water levels and water head over the main dam is discussed.

Suction caissons for cross-flow tidal power system

This paper describes a geotechnical site investigation and feasibility study of suction caisson foundations for fixed seabed tidal substructures in soft clay as part of the first US commercial-scale, grid-connected, tidal power installation located in Cobscook Bay, Maine. Feasibility was analysed through two-dimensional plane strain numerical modelling of the maximum capacity of a pair of rigidly connected suction caissons experiencing combined horizontal, vertical and moment loading when aligned with the direction of the current. Maximum load capacity for a single caisson diameter with varying skirt depths was investigated to determine effects of aspect ratio, uplift resistance of the windward leg and influence of shallow bedrock. Analyses in this paper indicate that suction caissons with relatively shallow skirts are a viable option to resist vertical and horizontal loading of the tidal power unit at the Cobscook Bay sites.

시화조력발전 연계에 의한 남시화 계통의 최적 운영 방안

본 연구에서는 시화조력발전소의 계통 연계에 따른 남시화 계통의 최적 운영 방안을 제안하였다.<BR> 남시화 계통의 최적 운영을 위하여 1분 단위의 시화호 해측의 수위를 예측하였으며, 예측된 시화방조제의 해측과 내측의 수위를 이용하여 시화조력발전소의 시간대별 발전량을 계산하였다. 특히, 남시화 계통에서 구입하는 전력은 시화조력의 계산된 시간대별 발전량을 이용하여 송전계통에서 전체 전력을 구입하는 방안, 조력발전이 가능한 시간대에 생산되는 모든 전력을 구입하는 방안 그리고 송전계통과 조력발전으로부터 전력구입 비용을 비교하여 구입하는 방안을 마련함으로써 부존자원이 부족한 우리나라에서 에너지 절약에 기여할 수 있는 최적의 운영 방안을 제시하였다.

Energy accounting of alternative energy sources

An energy accounting study has been made of the five alternative energy resource systems—solar, geothermal, wind, wave and tidal power. Owing to a lack of suitable data, a consistent methodology could not be pursued and a detailed comparison of these five systems with regard to likely energy ratios is not possible at the present time. (The energy ratio is here defined as being the total amount of energy obtained from a given system over its lifetime, divided by the total inputs of energy to that system in order to establish and maintain it in operation throughout its life.) There is a spread of possible energy ratios for each system studied, depending upon the assumptions made but, in each case, a value of about 10:1 is seen as a reasonable possibility for the future. The significance of this 10:1 energy ratio is that it could mean that our primary fossil fuel resources, when used to generate electricity through wind, wave or tidal power systems, would go about 33 times as far as they would if used in the conventional way. In the case of solar and geothermal energy, the savings factor would be somewhat less than 33; it could be somewhere between 6 and 30, depending upon system design, local conditions, etc. Energy pay-back times appear to be short for all the systems studied, the longest being about four-and-a-half years. This exercise has revealed just how much our primary non-renewable fuels could be conserved by using them to operate renewable energy resource systems although economic assessments at the present time might not provide justification for such a policy.

Energy analysis of wave and tidal power

Energy requirements for building wave and tidal-power systems have been estimated. For wave-power systems, the relationship between energy requirements and extraction efficiency is examined. It is found that a point of maximum net output is reached, beyond which further increases in extraction efficiency result in decreased net energy. Energy analysis thus identifies a limit on the energy which could, in principle, be extracted by a wave-energy system. Although similar limits could be identified for other types of energy source, the tidal-power analysis is confined to a brief comparison of energy inputs and outputs.