Tidal Energy Research Articles

Hydrokinetic tidal energy resource assessment following international electrotechnical commission guidelines

Energetic tidal streams are an especially attractive source of clean energy due to the daily occurrence of high tidal flows. However, before any deployment of tidal turbine farms, it is essential to perform a resource assessment depending on the scope and scale of the project. The International Electrotechnical Commission has developed a technical specification for assessing the tidal stream resource “IEC TS 62600-201” to aid in this effort: determine a particular site’s feasibility and design the project layout. In this study, we implemented and validated a three-dimensional numerical model and provided results following the specification for a ‘Stage 2’ project layout design in a highly energetic tidal channel: Tacoma Narrows of Puget Sound, in the State of Washington, USA. Implementation of the numerical model based on the specification has helped estimate the annual energy production with higher model accuracy. We also used the same setup to evaluate the undisturbed theoretical and technical resources, where the latter included energy extraction from the flow field arranging a hypothetical tidal energy converter array. Ultimately, this work has shown the important role of the technical specification in larger project layout design, which can simultaneously act as a benchmark for other ‘Stage 2’ theoretical and technical resource assessment studies worldwide.

Assessing geomorphological changes in coastal lagoon inlet using geospatial tools: A case study Moulay Bousselham lagoon, Morocco

Coastal monitoring is crucial for coastal management and both sustainable progress and environmental protection. This study aims to assess the morphodynamic changes undergone by an inlet, sandpits, and adjacent beaches of Moulay Bousselham lagoon (Morocco Atlantic coast), considered a RAMSAR site of significant biodiversity. Firstly, a Digital Shoreline Analysis System (DSAS) is applied to monitor shoreline evolution between 1949 and 2021, based on the End Point Rate (EPR) and Linear Regression Rate (LRR) methods, with the study area divided into south and north sides. Secondly, we mapped sandpit areas in the lagoon using recent satellite images and historical aerial photos covering a period of 75 years (1949–2024) within a GIS (Geographic Information System) environment. As a result, the average annual accretion rates on the north side, comprising 735 transects (1.45 km length), are +3.23 m/year (EPR) and +3.26 m/year (LRR). Additionally, the accretion phenomenon is observed in 117 transects, while erosion is recorded in 618 transects with −0.73 m/year and −0.81 m/year for EPR and LRR methods, respectively. The south side, comprising 1085 transects (2.46 km length), shows average annual erosion rates of −0.99 m/year (EPR) and −0.76 m/year (LRR) concerning the south part of the entrance inlet, with 278 transects showing accretion and 807 transects indicating erosion. Moreover, flood-dominated deltas (sandpit) mapping shows significant changes in the sandpit areas at the entrance inlet and inside the lagoon, with the area of accumulation increasing from around 155662,57 m2 in 1949 to 306020,22 m2 in March 2024. Inlet width measurements reveal fluctuations over time, from 53 m in 1949 to 177 m by 1988, reflecting dynamic coastal processes. However, by March 2024, the width decreased to 30 m, indicating sediment blockage and intense siltation. This analysis revealed that these sedimentation trends are mainly controlled by southward-directed littoral transport and the change in inlet position induced by several factors, including tidal currents, wave energy and river flow, particularly during winter seasons and extreme events (marine submersions and flooding). This article will help us to understand the relationship between the evolution of the coastline and its immediate influence on sediment supply to the lagoon.

Blockage and submersion depth effects on horizontal-axis tidal turbine (HATT) in a shear flow environment with wave–current interaction

Blockage and submersion depth effects on horizontal-axis tidal turbine (HATT) in a shear flow environment with wave–current interaction

Econometric Analysis of the Influence of Factors on the Share of Energy From Renewable Sources in the EU

The use of renewable energy is at the core of EU energy policy, reducing dependence on fossil fuels imported from non-EU countries, reducing greenhouse gas emissions and decoupling energy costs from oil prices. Currently, 22.5% of energy consumed in the EU comes from renewable sources. This increase over 2021 is due to strong growth in solar energy. This share is also increasing due to the consumption of non-renewable energy sources in 2022. According to expert forecasts, the share of renewable energy sources in Europe will continue to grow. Achieving the 42.5% target by 2030 will require a deep transformation of the European energy system. The very strong climate and energy policies pursued in the EU for about a dozen years and aimed at limiting emissions of harmful substances into the environment have led to a gradual abandonment of traditional energy sources. Increasing demand for energy while reducing its supply from traditional sources means that in order not to make the economy too dependent on energy imports, the dynamic development of renewable energy is necessary. The EU is therefore taking very extensive operational and strategic actions to use other sources for production, such as wind, solar energy, mechanical water energy, biomass and geothermal energy, as well as tidal waves, ocean heat, wave energy and sea currents. In this study, we assess the impact of energy, economic and environmental factors on the share of renewable energy in the EU. The aim of these studies was to identify the energy, economic and environmental indicators that have the greatest impact on the share of energy from renewable sources in the European Union. The study was conducted using the Statgraphics Centurion software package. The source data for the study was data from the official Eurostat website for the period from 2012 to 2022. The results of this study show that changes in gross domestic product in market prices per capita have a positive impact, as do changes in greenhouse gas emissions per capita negatively affect the share of energy from renewable sources in the EU in the period 2012-2022. This may most likely be due to the fact that EU countries are more likely to invest in renewable energy as they can afford to invest in the development of expensive renewable energy technologies and support subsidies for the promotion and regulation of renewable energy. The negative impact of per capita greenhouse gas emissions on renewable energy development is due to the high share of coal in the EU energy mix, meaning that coal not only has negative environmental impacts, but also negative environmental impacts. development of renewable energy.

Systematic Review of Computational Fluid Dynamics Modelling and Simulation Techniques Employed in Vertical Axis Hydrokinetic Turbines

At present, Computational Fluid Dynamics (CFD) is being utilized to explore tidal and hydrokinetic turbine systems, advancing comprehension of turbulent flow phenomena and raising the accuracy of performance predictions for these fluid-driven turbines. Consequently, this utilization of CFD contributes to the optimization of efficiency in these devices. Turbines are subject to variations from the best design point due to the influence of fluctuating flow rates, despite the findings of recent research that have identified the ideal design points. In contrast to conventional literature reviews, systematic analysis offers numerous advantages. The methodological strategy applied in this study entailed cross-referencing the findings obtained from Web of Science (WOS) and Scopus databases to establish the comprehensiveness as well as reliability of researcher data. Improving the review process, elevating the prominence of the field of study, and establishing critical priorities to mitigate research bias are all potential strategies for enhancing the quality of these evaluations. This research divides its findings into three core themes: (1) Performance assessment for practical implications, (2) Numerical analysis for theoretical insights, and (3) Design parameter optimization for engineering relevance. These themes collectively provide a well-rounded examination of the research outcomes across practical, theoretical, and engineering dimensions. Finally, the research findings have the potential to act as a significant point of reference for informing the best design considerations pertaining to vertical axis turbines.

Life cycle and economic assessment of tidal energy farms in early design phases: Application to a second-generation tidal device

Ocean currents are emerging as key contributors to renewable energy generation. However, technologies for harvesting tidal current energy are still in the early stages of development. In this context, environmental and economic studies on tidal energy converters (TECs) are crucial to further advance tidal technology and facilitate its entry into the market. This article presents a life cycle and economic assessment of a 34.5 MW tidal farm project comprising 23 second-generation tidal devices, each with a rated power of 1.5 MW. The tidal system was simulated using primary data from the full-scale floating platform Atir. The Atir is a pre-commercial tidal device designed with a steel trimaran and a submerged section for TEC installation. An assessment of 18 environmental impact categories was conducted using the ReCiPe 2016 MidPoint method, with process flow systems modelled using SimaPro v9.2.0.1 software. The environmental assessment indicates emissions of 42.11 g CO2eq per kWh, primarily stemming from manufacturing processes that demand substantial amounts of steel. The economic analysis reveals a Levelized Cost of Electricity (LCOE) of 0.125 EUR/kWh, consistent with European Commission projections. Although the platform structure represents a high initial investment, the lower maintenance costs of the Atir device provide long-term savings and, overall, result in a competitive LCOE. The study also introduces a methodological framework for harmonised environmental and economic assessments in tidal energy projects, proving crucial in supporting decision-making processes.

A Proposed Hybrid Machine Learning Model Based on Feature Selection Technique for Tidal Power Forecasting and Its Integration

Renewable energy resources are playing a crucial role in minimizing fossil fuel emissions. Integrating machine learning techniques with tidal power forecasting could greatly enhance the accuracy and reliability of predictions, which is crucial for efficient energy production and management. A hybrid approach combining different methods often yields better results than relying on individual techniques. The accuracy of tidal current power is very important, especially for smart grid applications. This work proposes hybrid adaptive neuro-fuzzy inference system (ANFIS) with the Kalman filter (KF) and a neuro-wavelet (WNN) for tidal current speed, direction, and power forecasting. The turbine used in this study is driven by a direct drive permanent magnet synchronous generator (DDPMSG). The predictions of individual and hybrid models including the ANFIS, the Kalman filter, and the WNN for tidal current speed and the power it generates are compared with another dataset as a way of validation which is the tidal currents direction. Also, other published work results in the literature are compared to the proposed work. Different hybrid models are proposed for smart grid integration. The results of this work indicate that the hybrid model of the WNN and the ANFIS for tidal current power or speed forecasting has the highest performance compared to all other models.

Influence of wakes interaction and upstream turbulence on three tidal turbines behaviour

The current study presents numerical results on three tidal turbine models (two in front, one downstream) interacting in a turbulent upstream flow. The numerical results come from a lifting-line (LL) embedded in a Lagrangian vortex particle (VP) solver: Dorothy LL-VP. The objective is to assess the extent to which this numerical tool is suited to reproduce accurately wakes interaction as well as fluctuating loads perceived by the downstream turbine. To this aim, the numerical set-up reproduces an experimental campaign led at IFREMER’s wave and current flume tank. The downstream turbine is placed at different positions to change the wakes interaction. Two upstream turbulence intensities (TI) experimentally tested are reproduced numerically using the synthetic eddy method (SEM). Favourable comparisons are obtained between numerical and experimental wakes, including velocity profiles. Preliminary results suggest that the downstream turbine performance decrease is numerically well captured. More investigations are needed on the loads fluctuations with longer computation time, and adding an angular velocity controller as well as hub modelling to Dorothy LL-VP.

A general framework for the design of efficient passive pitch systems

Mitigating the impact of variable inflow conditions is critical for a wide range of engineering systems such as drones or wind and tidal turbines. Passive control systems are of increasing interest for their inherent reliability, but a mathematical framework to aid the design of such systems is currently lacking. To this end, in this paper a two-dimensional rigid foil that passively pitches in response to changes in the flow velocity is considered. Both an analytical quasi-steady model and a dynamic low-order model are developed to investigate the pivot point position that maximizes unsteady load mitigation. The paper focuses on streamwise gusts, but the proposed methodology would apply equally to any change in the inflow velocity (speed and/or direction). The quasi-steady model shows that the force component in any arbitrary direction can be kept constant if the pivot lies on a particular line, and that the line coordinates depend on the gust and the foil characteristics. The dynamic model reveals that the optimum distance of the pivot location from the foil increases with decreasing inertia. For a foil at small angles of incidence, the optimum pivot point is along the extended chord line. This knowledge provides a methodology to design optimum passively pitching systems for a plethora of applications, including flying and swimming robotic vehicles, and provides new insights into the underlying physics of gust mitigation.

Hydrodynamic characteristics of a ducted tidal turbine in yawed conditions

In marine environments, tidal currents exhibit periodic changes in both direction and velocity. Consequently, tidal turbines often operate under yawed conditions. While conventional horizontal-axis turbines show decreased performance and undergo periodic load fluctuations due to blade rotation when yawed, research on the effects of yaw on ducted turbines has been sparse, leaving the underlying impact mechanisms poorly understood. This paper presents a three-dimensional hydrodynamic model of a ducted turbine, developed using the computational fluid dynamics method and validated through flume experiments. The hydrodynamic characteristics of the ducted turbine when operating under yawed conditions are analyzed using large eddy simulation. The findings indicate that yaw does not alter the optimal rotational speed of the ducted turbine. The turbine performance remains superior to non-yawed conditions up to a yaw angle of approximately 7°, peaking with a 1% improvement at 5°, but deteriorates beyond this point, declining by 1.5% at a yaw angle of 10°. In addition, yaw causes a deflection in the wake of the ducted turbine. This deflection increases with the yaw angle, reaching its maximum at a yaw angle of 10° with an angle of about 3.4°, before diminishing. The duct structure significantly influences this deflection, while rotor rotation has a minimal impact on wake deflection.

Tidal range energy conversion from Benoa, Bali

Abstract As one of the oceanographic parameters, the tidal range can be used as a source of blue energy in producing renewable energy such as electricity in Indonesian territory, especially in small islands. Utilization of tidal ranges in producing electrical energy will be more environmentally friendly when compared to Steam-Electric Power Station, which require coal resources as a power source. This research aims to determine the potential for renewable energy from tides in Benoa waters, Bali. The data used in this study is sea level data from tide gauges sourced from the University of Hawaii Sea Level Center (UHSLC). Analysis of tidal types and components in this study was carried out using the least squares method using the R program language. The results showed that the tidal type of Benoa waters is a mixed-semidiurnal tide. In 2020 and 2022, the highest tidal ranges are 2.46m (in December) and 2.3m (in March, November, and December), respectively. The simulation results for a 1000 m2 pond show that the energy potential in 2020 is 24.0 kWh and in 2022 it is 27.7 kWh. The tidal value’s magnitude influences the tidal energy potential; the more significant the tidal value, the greater the energy produced.

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.

Recognition method of turbine pollutant adhesion in tidal stream energy generation systems based on deep learning

In light of the extended exposure of tidal stream energy generation systems to seawater, which can lead to marine biofouling and subsequent reductions in turbine efficiency, this paper presents a deep learning-based method for the identification of pollutant adhesion. This method aims to rapidly assess the status of turbine pollutant adhesion in tidal energy generation systems. A dataset of adhesion images from tidal stream energy generation system under varying levels of pollution was obtained through underwater experiments with artificial fouling. Three different deep learning algorithms were employed to investigate the enhancement of underwater biofouling image quality. Image segmentation algorithms were used to extract and identify information related to the location and area of biofouling. The results demonstrate that the proposed deep learning-based pollutant adhesion identification method effectively recognizes the adhesion status on turbine blades, improving the accuracy of pollutant identification. This approach provides an efficient and accurate means of pollutant adhesion detection and management for the operation and maintenance of tidal stream energy generation systems, ultimately reducing operational costs.

Biodegradable flexible triboelectric nanogenerator for winter sports monitoring

With the energy crisis and environmental pollution becoming a growing concern worldwide, the development of clean and renewable energy from the environment has become an imperative for human survival and development. However, the equipment used to harvest clean renewable energy is large, subject to environmental impacts and regional differences (such as wind, solar and tidal energy). In this study, a biodegradable eggshell membrane triboelectric nanogenerator (EM-TENG) is introduced for the purpose of harvesting low-frequency mechanical energy. A Wireless Intelligent Motion Monitoring System (WIMMS) has been created using EM-TENG. It includes a Bluetooth sensor terminal and an intelligent processing terminal for digital signal reception on a host computer. The EM-TENG can be attached to knee and ankle joints to monitor posture. Therefore, for real-time monitoring of joint and kinetic chain changes during land training of ice dance athletes, the intelligent ice dance land training aid system is important. As a wearable motion monitoring sensor, EM-TENGs application in intelligent motion monitoring, intelligent wearable devices and big data analytics is being promoted.

Preliminary Assessment of Tidal Power Potential Along the Andaman Islands, India

Preliminary Assessment of Tidal Power Potential Along the Andaman Islands, India

Local and regional interactions between tidal stream turbines and coastal environment

An extended three-dimensional unstructured ocean model for simulating impacts of tidal stream turbines on tidal current, turbulence and surface waves has been applied to study the interactions between a tidal turbine farm and its surrounding environment. The present study aims to reveal three-dimensional local and regional changes due to the operation of a proposed turbine farm in natural coastal environment. Fine mesh size is assigned at the turbine farm location to capture the details of local wake dynamics, hydrodynamics and suspended sediment transport. Large geographic coverage of the model provides details of changes in regional features. Results showed that the proposed turbine farm comprised of 18 turbines (15–20 m in diameter) with approximately 20% power extraction from the average available power (averaged over five and half tidal cycles) led to local variation of surface elevation within the range of −10 to 3 mm, flow acceleration on both sides of the turbine farm, flow acceleration of ∼ 0.4 m/s near the bed in the vicinity of the turbine farm which caused bed shear stress to rise up to 2.5 N/m2 (corresponding to the critical stress of a range of fine gravel and finer sediment particles), locally increased TKE of 0.09 m2/s2, reduced wave height of 0.01–0.05 m, and upward sediment transport in the water column. On a regional scale, most of the changes on amplitude and phase of M2 constituent were observed within 10 km (∼ 15 times the array width) from the centre of the turbine farm, and the wake in terms of 95% flow rate recovery was found to be 9 km long (∼ 14 times the array width). Noticeable changes were also found in surface waves, bed shear stress and suspended sediment transport on regional scale as result of moderation in tidal and flow dynamics, although much less prominent than the local effects. It is recommended that consideration during the Environmental Impact Assessment stage of tidal stream energy projects should be given to an area that extends beyond the immediate vicinity of the planned turbine farm.

Accelerated seawater ageing and fatigue performance of glass fibre reinforced thermoplastic composites for marine and tidal energy applications

The use of thermoplastic composites as a sustainable alternative to thermosets is gaining increasing popularity due to their improved recyclability at the end of life. The fatigue performance of glass fibre/acrylic, glass fibre/acrylic- polyphenylene ether, and glass fibre/epoxy specimens, under three distinct upper stress levels (R-ratio = 0.1; f = 5 Hz) was studied. S–N curves were established for these specimens both before and after immersing them for three months in seawater (temperature: 50 °C). The dry thermoplastic composites exhibited similar fatigue performance to the thermoset counterpart at higher stress levels, with thermosets showing greater endurance at lower stress levels. Interestingly, the aged specimens showed comparable fatigue endurance, with a slight advantage in favour of the thermoplastic composites and less variability in their data. This study offers important insights into the fatigue performance of thermoplastic composites, emphasising their potential as sustainable alternatives to conventional thermoset composites for various marine applications.

Sustainable CO2 Refrigeration System for Fish Cold Storage Facility Using a Renewable Integrated System with Solar, Wind and Tidal Energy for Cape Verde—Analyzing Scenarios

This study compares four feasible alternative solutions for an integrated cold storage system in the city of Tarrafal, Santiago, Cape Verde. Integrated systems using grid electricity are compared with autonomous systems generating electrical energy from renewable sources, alongside various types of refrigeration facility systems. Its objective is to assess the energy efficiency, financial feasibility, and environmental impact across four scenarios. Scenario 1 utilizes two R134a refrigeration units powered by the public grid. Scenario 2 employs a transcritical R744 (CO2) system using grid electricity. Scenario 3 incorporates R744 and autonomous renewable energy. Scenario 4 employs R744 for refrigeration with seawater heat exchange and autonomous renewable energy sources. The findings favor Scenario 4, emitting 15,882 kg CO2 eq with a 5-year return on investment. Autonomous electricity production in this scenario reduces emissions by 95%. Despite an initial cost of EUR 769,172.00, Scenario 3 demonstrates financial viability, contributing to energy sustainability. This autonomous production reduces emissions by 360,697 kg CO2 compared to conventional systems, highlighting the positive impact of local renewable energy integration.

Numerical Study on Hydrodynamic Performance of a Pitching Hydrofoil with Chordwise and Spanwise Deformation

The hydrofoil plays a crucial role in tidal current energy (TCE) devices, such as horizontal-axis turbines (HATs), vertical-axis turbines (VATs), and oscillating hydrofoils. This study delves into the numerical investigation of passive chordwise and spanwise deformations and the hydrodynamic performance of a deformable hydrofoil. Three-dimensional (3D) coupled fluid–structure interaction (FSI) simulations were conducted using the ANSYS Workbench platform, integrating computational fluid dynamics (CFD) and finite element analysis (FEA). The simulation involved a deformable hydrofoil undergoing pitching motion with varying elastic moduli. The study scrutinizes the impact of elastic modulus on hydrofoil deformation, pressure distribution, flow structure, and hydrodynamic performance. Coefficients of lift, drag, torque, as well as their hysteresis areas and intensities, were defined to assess the hydrodynamic performance. The analysis of the correlation between pressure distribution and deformation elucidates the FSI mechanism. Additionally, the study investigated the 3D effects based on the flow structure around the hydrofoil. Discrepancies in pressure distribution along the spanwise direction result from these 3D effects. Consequently, different chordwise deformations of cross-sections along the spanwise direction were observed, contributing to spanwise deformation. The pressure difference between upper and lower surfaces diminished with increasing deformation. Peak values and fluctuations of lift, drag, and torque decreased. This study provides insights for selecting an appropriate elastic modulus for hydrofoils used in TCE devices.

Changes in sedimentary environments in Shihwa Lake, Korea

Shihwa Lake was an artificial freshwater lake formed in 1994 by constructing a 12.7-km-long seawall, but it became a seawater lake in 1997. The water quality of Shihwa Lake had not been recovered despite the seawater exchange through the drain gate. This may adversely affect not only the water but also the bottom sediment environment of the lake. To determine the possible reasons for the environmental deterioration, water and core samples from three points in the lake were collected. And the parameters, such as the water temperature, salinity, dissolved oxygen (DO), particle distribution, total carbon (TC) and total nitrogen (TN), C/N ratio, and radioactive strength, were measured to estimate the water and sediment quality. In addition, we investigated changes in the sedimentation environment based on heavy-metal analysis, stable-isotope analysis of the core sample, and numerical analysis of sand transport. The core-sample analysis revealed a change in the sedimentation process on a time basis (before, during, and after the construction of the seawall). As a result, the sedimentation rate was approximately 4 cm/year during the seawall construction and 2 cm/year after the construction near the center of the lake. Furthermore, we established that the trends in these calculated sedimentation rates, determined using the radioactive strength method, align consistently with the results obtained from simulations and ultrasonic-wave observations. Finally, we evaluated the effects of a tidal power plant on the exchange of seawater and sedimentation processes.