Tidal energy

A simulation model of hybrid solar drying as alternative sustainable drying system for herbal and medicinal plants was developed. Heat absorbed from the solar radiation, heat gained by the collector and supplemented by the burner, heat gained or lost by the product, heat gained or lost through the drying bin wall, heat gained or lost with the drying air and the latent heat of the moisture evaporation from the product were the main components of the equations describing the drying system. The model was able to predict the moisture loss from the product at a wide range of temperatures and air recirculation percentages (70, 80 and 90%). The energy consumption for drying herbs was investigated by using of different energy sources including solar energy, diesel and propane fuels. Experiments were conducted to validate the simulated model results. The results indicated that the solar collector could raise the temperature by 5-13 oC. The mint moisture content was dried from 80% to MC range...

Tidal energy is a renewable energy source that provides sustainable energy through the utilization of tidal differences, making it a very promising option. This study examines a more effective tidal energy reservoir model by building a 1:100 scale prototype in the laboratory with several predetermined variations, namely an earthen pond (100, 80, and 60 cm), and flow holes (1.5, 1, and 0.5 cm) with initial tidal height differences of 10 cm, 15 cm, and 20 cm. The model uses a 6-hour time period, which corresponds to a semidiurnal tidal model. The results showed that the highest energy output was 281.84 kWh, achieved with a 1.5 cm flow hole, 20 cm tidal height difference for the initial condition, and 80 cm pond width. For a 1 cm flow hole, the outputs were 1774.8 kWh and 1803.78 kWh for 15 cm and 20 cm tidal height difference for the initial condition with a pond width of 100 cm. Meanwhile, the 0.5 cm flow hole produces potential energy outputs of 2623.8 kWh and 2611.4 kWh for different tidal heights of 15 cm and 20 cm for the initial condition with a pond width of 100 cm. Better model performance can be connected to a mini generator to validate the energy generated from the designed prototype model.

Green energy refers to energy derived from natural, renewable sources that have a minimal impact on the environment. This form of energy is essential for sustainable development, as it helps reduce greenhouse gas emissions and combat climate change. Key sources of green energy include solar power, which harnesses sunlight through solar panels; wind power, which utilizes wind turbines to convert wind energy into electricity; and hydropower, which generates energy from flowing or falling water. Biomass energy, derived from organic materials such as plants and waste, and geothermal energy, which taps into the Earth's internal heat, are also significant contributors to the green energy landscape.

Financial viability and political will ultimately determine if tidal range power schemes are developed. This research aims to demonstrate a robust system to make initial estimates of capital costs for tidal range schemes that can be compared between systems and options. A levelised cost of energy (LCOE) is used to compare a tidal range barrage (Morecambe Bay) and a coastal tidal lagoon (North Wales) in the UK; the schemes are set in context with other common energy sources. The results show the Morecambe Bay barrage generates marginally more electricity than the North Wales coastal lagoon and has a shorter impoundment at lower cost. However, the economic arguments for both schemes are similar; both are viable as the LCOE shows. Despite being shown to be financially viable, the sources of funding may remain a problem. Financial returns and two potential public funding mechanisms are discussed. The approach using two simple models makes a strong case for more detailed analysis and, in...

A methodology for assessment of the potential impacts of extraction of energy associated with astronomical tides is described and applied to a site on the Beaufort River in coastal South Carolina, U.S.A. Despite its name, the site features negligible freshwater inputs; like many in the region, it is a tidal estuary that resembles a river. A three-dimensional, numerical, hydrodynamic model was applied for a period exceeding a lunar month, allowing quantification of harmonic constituents of water level and velocity, and comparison to values derived from measurements, recorded at a location within the model domain. The measurement campaign included surveys of bathymetry and velocity fields during ebb and flood portions of a tidal cycle for model validation. Potential far-field impacts of a generic tidal energy conversion device were simulated by introducing an additional drag force in the model to enhance dissipation, resulting in 10-60% dissipation of the pre-existing kinetic power within a flow cross-section. The model reveals effects of the dissipation on water levels and velocities in adjacent areas, which are relatively small even at the 60% dissipation level. A method is presented to estimate the optimal vertical location for the energy conversion device and the potential power sacrificed by moving to a different altitude.

A methodology for assessment of the potential impacts of extraction of energy associated with astronomical tides is described and applied to a site on the Beaufort River in coastal South Carolina, U.S.A. Despite its name, the site features negligible freshwater inputs; like many in the region, it is a tidal estuary that resembles a river. A three-dimensional, numerical, hydrodynamic model was applied for a period exceeding a lunar month, allowing quantification of harmonic constituents of water level and velocity, and comparison to values derived from measurements, recorded at a location within the model domain. The measurement campaign included surveys of bathymetry and velocity fields during ebb and flood portions of a tidal cycle for model validation. Potential far-field impacts of a generic tidal energy conversion device were simulated by introducing an additional drag force in the model to enhance dissipation, resulting in 10-60% dissipation of the pre-existing kinetic power within a flow cross-section. The model reveals effects of the dissipation on water levels and velocities in adjacent areas, which are relatively small even at the 60% dissipation level. A method is presented to estimate the optimal vertical location for the energy conversion device and the potential power sacrificed by moving to a different altitude.

When tidal turbines are utilized in the most energetic waters where there are significant waves, the assessment of the surface wave effects are of great concerns. The objective of this paper is to contribute to a fundamental understanding of surface wave effects on tidal turbines. A numerical model was developed based on the modified Blade Element Momentum theory with an inclusion of added mass effects, wave excitation forces and a one degree-of-freedom (DOF) simulation for turbine rotational motion. The experiments on a 1:25 scaled tidal turbine were performed in a towing tank. It is shown that the surface waves did not affect the average loads and power output, but caused severe periodical oscillations. The amplitudes of the cyclic thrust and torque could reach up to 50% of the mean value induced by the incident waves with period of 1.6 s and height of 14 cm. Non-dimensional response amplitude operators (RAOs) of thrust and torque were proved to be sensitive to submergence of the turbine. The wave induced torque and thrust tend to a fixed value when the incident wave length is much longer than the water depth, which provides an approximate assessment of the surface wave effects on tidal turbines.

This paper specifically focuses on site-specific CFD modelling in the context of tidal energy development, and presents results for two sites from the Fundy Tidal Region (FTR) situated in Eastern Canada. The FTR is one of the best and most energetic areas in the world for tidal energy development. To efficiently meet the computational demands of modelling unsteady three-dimensional turbulent flow in complex tidal zone terrains, highly parallel GPU hardware are utilized. Strategically deployed Acoustic Doppler Current Profiler (ADCP) measurements at two tidal turbine locations provide validation of the predictions under ebb and flood flows. The processing methodology of ADCP devices is incorporated into the CFD simulation to improve predicted turbulence levels for validation. The simulations use detached eddy simulation (DES) turbulence modelling with engineered inlet boundary conditions and realistic bathymetry. The inlet boundaries use mean horizontal velocity values interpolated from regional tidal simulations and are perturbed by synthetic turbulence to accelerate boundary layer development. Simulations cover tidal developments from ~1.5 to 3 square kilometres with spatial and temporal resolutions of 1-2 m and 0.1 s, respectively.

SCORE -Sustainability of using Ria Formosa Currents On Renewable Energy production -proposes to test for the first time on Portuguese waters a floatable tidal energy converter (TEC), the Evopod 1:10th scale 1kW (E1) prototype from OceanFlow Energy Ltd. The innovative aspect of TEC testing in Portugal lies with the unique morphological characteristics associated with the device deployment site at Ria Formosa, a coastal lagoon protected by a multi-inlet barrier system located in southern Portugal. It is therefore ideal to analyse both the energy extraction efficiency and eventual impacts that extracting energy from the flowing currents will have on the ecological communities and physical settings of a shallow-water estuarine environment.

A B S T R A C T Today, as a rapidly expanding industry within the energy sector, sustainable energy generation through renewable sources such as tidal power creates the potential to get into previously untapped resources. This paper focused on designing, simulating, and analyzing a single rotor tidal turbine and contra-rotating (double rotor) tidal turbine with traditional blade designs and whale-inspired blade designs by using computational analysis. A contra-rotating tidal turbine has a lot of advantages such as near zero reactive torque on the support structure, near-zero swirls in the wake, and high relative inter-rotor rotational speeds. Contra-rotating turbines have capabilities of harvesting higher energy by eliminating the swirling velocity component in the wake as results from the numerical analysis models. Numerical flow visualization proved that the wake verified the reduction of swirl behind the turbine and as expected, the contra-rotating with whale tip blades turbine w...

The classical Blade-Element/Momentum-Theory for horizontal-axis wind turbines neglects hub-blockage effects, which can be significant for small and micro turbines with moderate or high dimensionless hub radii. This paper presents an innovative strategy to introduce a hub blockage factor in the Blade-Element/Momentum-Theory without altering its classical solution algorithm. The model assumes that the axial velocity at the disk can be computed as the superposition of its value in the hubless case and the bare-hub inducedvelocity. Hence, the approach implicitly assumes that the hub induced-velocity is independent of operating conditions, and, therefore, it can be predetermined and provided as input to the solution procedure. The validity of this assumption is thoroughly and successfully verified. The model accuracy is tested by comparing its results against experimental data and an advanced Computational-Fluid-Dynamics-Actuator-Disk model, which inherently considers the hub blockage. Detailed analyses are conducted for turbines with high (25%), moderate (15%) and low (7%) values of the dimensionless hub radius. In all cases, the enhanced Blade-Element/Momentum-Theory demonstrates significantly improved accuracy in predicting both global (power and thrust coefficient curves) and local flow quantities (blade forces, angle of attack, mean axial induction factor).

Developers have proposed many in-stream tidal projects, but few commercial-scale devices have moved beyond the planning stages to construction and testing. To better understand social impediments to pilot project siting, this comparative case study was conducted in urban Puget Sound, Washington and remote Iguigig, Alaska. Stakeholder interviews were coded to identify themes about project development. Providing local renewable energy, advancing science and technology, and environmental awareness were perceived benefits, while negative environmental impacts, conflicts with other uses, and unintended consequences were perceived concerns of tidal energy. The major themes were: 1) organizations influence siting in urban areas while residents influence siting in rural areas; 2) stakeholder groups cited the wellbeing of their members to justify their stances on in-stream tidal energy projects; and 3) project siting was more successful where there was a simple and uniform assemblage of stakeholders and views. Stakeholders in the smaller, more uniform community were the most supportive of in-stream tidal energy because of a greater need for energy due to fewer energy options. Thus, siting in remote communities could allow tidal energy development to progress in mutually beneficial ways and help states like Washington and Alaska achieve their renewable energy portfolio goals.

Power measurements in a scale model wind farm: Results from varying array size, arrangement, spacing, and setpoints DAN HOUCK, ED-WIN COWEN, Cornell University -The current trend in wind energy research is to optimize wind farms as opposed to optimizing individual turbines. There is also an emerging idea to consider the wind turbines themselves as actuators that can be used to intentionally and beneficially manipulate the flow to improve the power output of the wind farm. To this end, we completed a series of experiments with an array of 18 model-scale wind turbines in a 2 m wide flume testing changes in the number, arrangement, and spacing of the turbines as well as the setpoint, or power production, of each turbine. Each treatment case is compared to a similar control case that was arranged and operated more conventionally with all turbines attempting maximum power production. A highly accurate torque transducer provides calibrations allowing non-intrusive mechanical power measurements of each turbine. Comparisons are made on the basis of overall power output, array efficiency (total power output of the N-turbine array divided by N of an upstream turbine operating at max power), and power density (power per area). Particle image velocimetry (PIV) further reveals the fluid dynamics at work to create any improvements in power.

The Betz theory states that a horizontal axis wind turbine can only extract less than 16 27 (59.3%) of the kinetic energy of the wind. The value 16 27 (0.592) is called the Betz limit. In 1919, Albert Betz used a method that is analytic to derive the Betz theory and henceforth finding the Betz limit. In the theory, he derived momentum equations of an actuator disc (AD) in the stream of wind. In this research, a N ewton ′ s method scheme is used to reach the Betz limit. For the axial induction factor denoted by either a or a * we used a reasonable initial point guess of 0.259. The results agree well with the analytical results of the Betz theory. From the N ewton ′ s method scheme results corresponding to a and a * , the relative errors in comparison with the Betz limit are 4% and 0.9%, respectively. The small amount of errors shows the possibility of reaching the Betz limit using the N ewton ′ s method scheme. If alternate power coefficients [C p (a) or C p * (a * )] are found where the (exact) value (a or a * ) cannot exactly be found analytically, the N ewton ′ s method scheme would be an ideal way of estimating (or calculating) other proposed limits or the Betz limit. This method yields extremely accurate results. Furthermore, for a quadratic equation, the quadratic formula would do. However, if the quadratic equation has floating-point numbers, the N ewton ′ s method would be more appropriate.

Energy is the key input to drive an improve the life cycle. Primarily, it is the gift of the nature to the mankind in various forms. The consumption of energy is directly proportional to the progress of mankind. Today every country draws its energy needs from a variety of sources. We can broadly categorize these sources as commercial and non-commercial. The commercial sources include the fossil fuels (coal, oil and natural gas), hydro-electric power and nuclear power, while the non-commercial sources include wood, animal waste and agricultural wastes. This paper describes in brief the non-conventional energy sources there are abundant renewable sources of energy such as wind, sun, water, sea, biomass apart from even daily wastes. These sources are pollution free and hence clean energy apart from being unlimited/ inexhaustible. Current energy scenario indicates that the 75% of energy requirement is met by fossil fuels. Nuclear energy contributes to about 3% and 9% is met by hydel ene...

This paper describes the structural, design of a tidal turbine blade the study consists of measuring energy creation if a mechanism were to be placed in the sea flow below tidal areas. Growing concern over the threat of global climate change has led to be increased interest in research and development of renewable energy technologies. Most tidal current turbine design are focused on middle and large scale for deep sea, less attention was paid in low water level channel, such as the region around the islands, coastal seas and rivers. The ocean provides a vast source of potential energy resources and as renewab le energy. Tidal energy ortidal power is the power achieved by capturing the energy contained in moving water mass due to tides. two types of tidal energy can be extracted kinetic energy of currents between ebbing and surging tides and potential energy from the different in height between high and low tides.through this energy may not be able to be obtained all of the time, onl...

The study investigates the impact that construction of a Severn Barrage in the Severn Estuary, on the west coast of the UK, might have on local wave conditions. Implementation of a barrage will impact on tidal currents and water elevations in the wider region. There is strong tidal modulation of wave conditions under the natural regime and therefore barrage-induced changes to tidal conditions could affect wave modulation in the region. This paper uses Swan, an open source 3rd generation spectral wave model, to investigate the possible impacts of construction of a barrage on tidal modulation of the wave conditions. It is found that current variations, rather than water level variations, are the dominant factor in tidal modulation of wave conditions. Barrage implementation does not substantially change the modulation of the wave period or direction. However, barrage implementation does affect the tidal modulation of wave heights in the area of interest. The tidal modulation of the wave heights is generally reduced compared to the natural case; the peaks in the wave heights on an incoming tide are slightly lowered and there is lesser attenuation in wave heights on the outgoing tide. This modulation leads to net changes in the wave heights over one tidal cycle. For all of the tested wave conditions, this net change is small for the majority of the tested domain, namely to within ±5% of the no barrage case. There are some areas of greater change, most notably larger net increases in the wave heights near the North Somerset coast where the post construction net wave height increase over a tidal cycle approach 20% of the pre-construction conditions. These changes do not impact coastal flooding because the wave height increase is not co-incident with high tide. Importantly, the maximum wave height is not increased and thus the likelihood of extreme events is not increased. The area of greatest reduction is between Swansea and Porthcawl. Changes over a neap tidal cycle show similar patterns of net change, but the modulation over the tidal cycle is different; primarily the magnitude of modulation is half that for the spring tide case and the shape is altered in some locations.

Energy extraction from ocean tides via hydrokinetic turbines has recently attracted scientists and engineers attention as a highly predictable source of renewable energy. However, since the most promising locations in terms of resources and proximity to the end users are in ...

Electrical power generation by tidal energy provides various advantages. The energy is highly predictable, has less impact on ecological pollution and provides an indefinite amount of renewable energy. The countries like Canada, China, Russia, South Korea and France are extensively utilizing tidal sources of energy for the generation of electrical energy. A suitable site (where less construction is required), adequate tidal range and sufficient bathymetry; are the basic requirements for the installation of a tidal power plant however sometimes there is no tidal data available for suitable sites, like Khor Kalmat tidal lagoon in Pakistan. Therefore, the first time study is conducted to assess the tidal energy resources of the naturally blessed lagoon, Khor Kalmat, which is located in the Baluchistan province of Pakistan, by using geostatistical modeling. A geostatistical model is developed to estimate the tidal energy potential at Khor Kalmat by using observed data of five available ...

Acoustic Doppler current profilers (ADCPs) are commonly used to assess mean currents and turbulence at energetic sites. Since 2014, five-beam ADCP configurations have become more common, but conventional analysis of turbulence properties is still based on the four-beam Janus configuration. We use measurements from a single site to investigate whether improved estimates of turbulent kinetic energy (TKE)are made possible by the addition of a fifth vertical beam. We conclude that four-beam estimates of TKE are suitable in most cases, and exhibit lower variance than five-beam estimates, but are more prone to contamination by wave activity.

Acoustic Doppler current profilers (ADCPs) are commonly used to assess mean currents and turbulence at energetic sites. Since 2014, five-beam ADCP configurations have become more common, but conventional analysis of turbulence properties is still based on the four-beam Janus configuration. We use measurements from a single site to investigate whether improved estimates of turbulent kinetic energy (TKE)are made possible by the addition of a fifth vertical beam. We conclude that four-beam estimates of TKE are suitable in most cases, and exhibit lower variance than five-beam estimates, but are more prone to contamination by wave activity.

Understanding sequestration of carbon by coastal ecosystems is central to addressing the role they play in climate change mitigation. To quantify this process, accurate measurements of CO2 fluctuation, coupled with variations in residence time of coastal water-bodies are required. Nearshore ecosystems, including coastal lagoons, may provide an effective sink for atmospheric carbon dioxide, particularly those containing productive biota such as seagrass. However, the rate and pattern of carbon sequestration in seagrass meadows across a range of environmental settings is still poorly constrained. In this study, we utilize a robust physical tidal model, along with biogeochemical dissolved inorganic carbon (DIC) assessment, to estimate water residence time and net sequestration of atmospheric CO2 in an intertidal lagoon containing a seagrass (Zostera noltii) meadow. Total alkalinity and pH measurements taken from advected water mass exchanged with the open ocean at inlet boundaries are used to calculate DIC and pCO2. A predictive model of hydrodynamics provides good approximation of mean water residence time to within 6 hr (± 3 s.d). Results indicate that during the daytime study period the lagoon is a sink for carbon, having a mean net ecosystem productivity (NEP) of 3.0 ± 0.4 mmol C m -2 hr -1 . An equivalent diel NEP range of between 15.23 and -9.24 mmol C m -2 d -1 is calculated based on reported shallow water pelagic respiration rates. Moreover, approximately 4% of DIC availability occurs from atmospheric CO2 transfer to lagoon water. However, a negative diel rate of -82 ± 81 mmol C m -2 d -1 is found, assuming overnight respiration ascertained from converted Zostera noltii O2 utilization. We hypothesize that analogous regional nearshore ecosystems provide baseline study sites suitable to elucidate the carbon capture potential of planned, nearby tidal range energy schemes.

In this paper, the application of a 3D numerical model covering the area of Pentland Firth channel (Scotland, UK) to investigate the hydrodynamics related to tidal energy extraction is presented in detail. A full validation analysis is carried out so that the fully operational 3D hydrodynamic model could be applied with confidence in order to explore possible impacts of tidal devices on the ambient marine environment. Following that, a higher resolution hydrodynamic and morphodynamic model covering the area of Inner Sound channel, between the Island of Stroma and Scottish Mainland, favoured for tidal energy extraction inside Pentland Firth, is set up. Preliminary results indicate that the existing morphodynamics of the observed sandbank areas inside Inner Sound Channel are very dynamic. In such a dynamic environment, results imply that possible alterations in tidal currents due to energy extraction may have some implications on the existing morphodynamic regime.

The tidal energy sector is a growing industry in the UK and beyond. Energy developers' interests are progressing towards the deployment of large arrays of tidal energy converters (TECs). Numerous factors will affect decision making related to arrays siting and size. One key factor is the effect that the TEC arrays may have on the natural sediment transport patterns and the sea bottom morphodynamics. The Inner Sound Channel located between the Island of Stroma of Pentland Firth and the Scottish Mainland (UK) has been accredited for a large-scale TEC array installation to be developed in the future. Three morphodynamically active, large sandbanks are located in the Inner Sound channel. This study investigated the impacts of tidal energy extraction from a large array of TECs on the sediment dynamics and morphology of these sandbanks. A large-scale 3D hydrodynamic and morphodynamic Delft3D model was set up to computationally model Pentland Firth, Inner Sound Channel in order to study the impacts of tidal energy extraction from a generic TEC array, on the existing hydrodynamic and morphodynamic regime. A range of hypothetical energy extraction scenarios was modelled. Results reveal that the changes to morphodynamics of these sandbanks as a result of large scale tidal energy extraction far exceeds the morphology change under the natural hydrodynamic regime and that the severity of morphology change depends on the level of energy extraction.

A 3D numerical modelling study to investigate the existing hydrodynamic regime of the Pentland Firth Inner Sound Channel, Scotland, UK is presented. Hydrodynamics that govern some sensitive sedimentary deposits in the Inner Sound Channel are discussed. A 3D hydrodynamic model Delft3D is set up for Pentland Firth, located between Orkney Islands and mainland Scotland and a full sensitivity analysis of the numerical model is carried out. The current model set up sufficiently captures the existing hydrodynamics during a full spring-neap tidal cycle inside Pentland Firth. Using model results, the 3D structure of the dynamics of the tidal flows in the Inner Sound Channel is investigated. The temporal variability of tidal flows, the residual tidal flows in the channel and local flow interactions with the Island of Stroma are described. It is proved that the tidally dominant flows drive the sediment transport gradient model to explain the principle maintenance mechanisms of two island-associated sandbanks present in the Inner Sound. The present study provides detailed information on the physics of the tidal regime in the Inner Sound and explains the presence of sandbanks in an area of high tidal flows. Due to extremely high tidal flows, Inner Sound is considered as one of the most favourable sites for tidal energy extraction in the UK. The findings of this study will be very useful in assessing the significance of impacts of future tidal energy extraction on natural hydrodynamics and sediment dynamics of the area.

In this paper we describe a numerical modelling study carried out to investigate the prevailing sediment dynamics of two large sandbanks located at a site designated for future development of tidal stream energy extraction, in the Inner Sound Channel of Pentland Firth, Scotland, UK. A calibrated and validated 3D Delft3D hydrodynamic model covering Pentland Firth channel was combined with a morphodynamic model. The sea bed changes occurring around the sandbanks during a period of two spring-neap tidal cycles are described and discussed in detail. It was found that both sandbanks, which are located in a deep shelf region (depths N 18 m), are morphodynamically active and their existence and integrity are strongly linked with the existing hydrodynamic regime.

Deployment of co-located wind and tidal stream turbines is proposed as a method for reducing cost of electricity generation from either technology individually. Energy yield for wind turbines is modelled using an eddy viscosity wake model and for tidal turbines using a method of self-similar superposition of wake deficits. Yaw strategy is considered for the tidal turbines, finding that although a continuous yaw strategy generates highest yield, a slack-tide strategy offers a suitable compromise with mechanical complexity. A case-study of the MeyGen site in the Pentland Firth is considered for co-location. The addition of 12MW of wind capacity to a 20MW tidal array results in a twofold increase in annual energy yield, compared to operating the tidal turbines alone. Phasing of the tidal cycle means that during a neap tide, the combined system may be entirely dependent on wind generation, but during a spring tide there is a regular tidal supply. Steady state loads for wind and current ...

Reliability and storm survival of Marine Energy Converters are critical to their commercial development and deployment. The Intelligent Active Mooring System (IAMS) is a novel device intended to minimise extreme and fatigue loading in mooring lines through a non-linear loadextension curve that is variable in operation to adjust to the prevailing metocean conditions. A static model of IAMS, validated by physical model tests at the Dynamic Marine Component test facility at the University of Exeter, is used in a dynamic simulation of the performance of IAMS as part of the mooring system of the South West Mooring Test Facility buoy. A 10 m length of IAMS can reduce the rms line tension in normal operating conditions by up to 21% and the peak line tension in storm conditions by up to 21% when compared to braided nylon mooring lines. Peak line tension reductions of over 50% can be achieved if a longer IAMS unit is used. The resulting mooring system can be optimised to give load reductions in a wide range of metocean conditions; while variable pre-tension could be used for tidal range compensation or to ease access for installation and maintenance.

This paper presents a mathematical model to explain the phenomenon of tidal energy and the creation of a Matlab/Simulink to illustrate how the tidal current energy system works which is essential in power generation. A thorough explanation of tidal energy, including the science of tidal power, as well as the different operating mode has been discussed in this paper. Various literatures has been reviewed, the method used in this work were adopted from Sir Isaac Newton Famous Law of Gravitation. The derived model were applied in Matlab/Simulink, an output result were analyzed. Based on these result it was argued that tidal current has huge amount of energy that can be extracted and converted to a usable form. Tide can be predicted years in advance, its deployment has several benefits.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

This paper presents a mathematical model to explain the phenomenon of tidal energy and the creation of a Matlab/Simulink to illustrate how the tidal current energy system works which is essential in power generation. A thorough explanation of tidal energy, including the science of tidal power, as well as the different operating mode has been discussed in this paper. Various literatures has been reviewed, the method used in this work were adopted from Sir Isaac Newton Famous Law of Gravitation. The derived model were applied in Matlab/Simulink, an output result were analyzed. Based on these result it was argued that tidal current has huge amount of energy that can be extracted and converted to a usable form. Tide can be predicted years in advance, its deployment has several benefits.

World Resources Institute State of Climate Action 2023 "At a time when climate change is dramatically outpacing our efforts to stop it, we should all be part of the solution. " World Bank Climate Change at-a-Glance "We are now headed for around 2.7 degrees. This is still ruinously high" UN Climate Change 2023 Highlights. Climate Change Challenges 2024 provides insights on renewable energy, evolving weather patterns, science-based solutions, and the role of human psychology in addressing climate change.

This paper presents a mathematical model to explain the phenomenon of tidal energy and the creation of a Matlab/Simulink to illustrate how the tidal current energy system works which is essential in power generation. A thorough explanation of tidal energy, including the science of tidal power, as well as the different operating mode has been discussed in this paper. Various literatures has been reviewed, the method used in this work were adopted from Sir Isaac Newton Famous Law of Gravitation. The derived model were applied in Matlab/Simulink, an output result were analyzed. Based on these result it was argued that tidal current has huge amount of energy that can be extracted and converted to a usable form. Tide can be predicted years in advance, its deployment has several benefits.

The high penetration of renewable energy systems with fluctuating power generation into the electric grids affects considerably the electric power quality and supply reliability. Therefore, energy storage resources are used to deal with the challenges imposed by power variability and demand-supply balance. The main focus of this paper is to investigate the appropriate storage technologies and the capacity needed for a successful tidal power integration. Therefore, a simplified sizing method, integrating an energy management strategy, is proposed. This method allows the selection of the adequate storage technologies and determines the required least-cost storage capacity by considering their technological limits associated with different power dynamics. The optimal solutions given by the multi-objective evolutionary algorithm are presented and analyzed.

Arrays of offshore renewables are being studied by academia to justify them economically in real-world applications by private sector entities. Offshore renewables' initial and levelized costs are significantly higher than their on-land counterparts. Therefore, energy density per unit area should be dramatically increased and/or cost lowered. However, concurrent knowledge of offshore industries other than renewable energy, such as fish farms, offshore oil platforms, and marine shipping, implies that lowering costs will not be sufficient. In order to increase the energy density per unit area, multiple offshore renewable energy systems relying on different physics should be combined in threedimensional space, thus creating an array. Also, systems and structures of other marine industries can be included in the concept to benefit from their readily present infrastructure. Such arrays are the subject of scientific and engineering investigation and assessment since hydrodynamics, aerodynamics, mechanics, and economics are involved. The topic is highly multidisciplinary. In this work, we reflect on the present situation and project future aspects.

Arrays of offshore renewables are being studied by academia to justify them economically in real-world applications by private sector entities. Offshore renewables' initial and levelized costs are significantly higher than their on-land counterparts. Therefore, energy density per unit area should be dramatically increased and/or cost lowered. However, concurrent knowledge of offshore industries other than renewable energy, such as fish farms, offshore oil platforms, and marine shipping, implies that lowering costs will not be sufficient. In order to increase the energy density per unit area, multiple offshore renewable energy systems relying on different physics should be combined in threedimensional space, thus creating an array. Also, systems and structures of other marine industries can be included in the concept to benefit from their readily present infrastructure. Such arrays are the subject of scientific and engineering investigation and assessment since hydrodynamics, aerodynamics, mechanics, and economics are involved. The topic is highly multidisciplinary. In this work, we reflect on the present situation and project future aspects.

Unlocking the vast potential of our ocean as a sustainable energy resource requires a comprehensive understanding of their power to fully realize their enormous potential as a sustainable energy source. This assessment explores into the depths of ocean energy, exploring its abundance, variability, and technological possibilities. Some technologies or ways of harnessing the ocean’s available energy are through Wave Energy Conversion, Ocean Thermal Energy Conversion (OTEC), and Salinity Gradient.
Typical techniques used by the International Electrotechnical Commission to quantify wave energy measures the ocean's total wave resource, yet a substantial amount of this resource is unfit for use with particular wave energy converters (WECs) (Dunkle, et al, 2022).
The process known as Ocean Thermal Energy Conversion (OTEC) makes use of the water's natural temperature gradient to produce energy. OTEC plants can be constructed on land, on mobile vessels, or on offshore platforms anchored to the continental shelf (Solar Energy Research Institute, 1989).
As mentioned by Yip and Elimelech (2012), the energy released when waters with varying salt content combine is known as salinity gradient energy. The osmotic principle is demonstrated in the energy release when mixing fresh water and saltwater (Helfer et al., 2013).
Thus, the mentioned technologies on harnessing this renewable energy requires an effective way of resource assessment. All these technology helps in the course of transition towards a greener, more resilient energy future.

Ferrites and Different Winding Types in Permanent Magnet Synchronous MotorThis paper deals with design of permanent magnet synchronous machines with ferrites. The ferrites became popular due to their low cost and cost increasing of NdFeB. The progress in ferrite properties in the last decade allows the use of ferrites in high power applications. Three models of ferrite motors are presented. It is shown that also the type of stator winding and the shape of the slot opening have an important effect on the PMSM properties. The first motor has a distributed winding, the second motor has concentrated, non-overlapping winding and open stator slots. The third motor has a concentrated non-overlapping winding and semi - open slots. All models are designed for the same output power and they do not have the same dimensions. The paper shows how important the design of an electric machine is for excellent motor properties or better to say how the motor properties can be improved by an appropriat...

A high spatial resolution three-dimensional (3D) hydrodynamic ocean model of the Orkney Islands is used to investigate the tidal stream resource and physical environmental impact in the Pentland Firth, a high-resource area where the first arrays of tidal stream turbines are likely to be deployed in Scotland. Tidal stream turbines are represented in the model using a momentum sink in order to (1) find an upper bound estimate of the available resource, (2) explore alternative, more realistic scenarios, and (3) estimate their effect on the physical environment. The maximum extractable power scenario (M 2 þ S 2 cycle mean of 5.3 GW) requires a high density of turbines deployed through the channels cross section and has a major impact on the physical environment. More realistic scenarios, with the placement of the turbines constrained by practical factors, resulted in considerably less extractable power but the physical environmental impact was disproportionately reduced. It was also found that a variable thrust coefficient can be used to optimise the performance of tidal arrays. Our work highlights the usefulness of 3D hydrodynamic models for tidal stream resource assessment and impact studies, and illustrates how the design of tidal stream arrays can affect the levels of sustainably harnessed tidal power.