Tidal Stream Energy

The Severn Estuary is an ideal site for tidal renewable energy projects and the probability of coastal flood risk in the estuary will increase accordingly due to climate change. Therefore, it is significant to predict the future status of coastal flooding in this estuary using various scenarios with the effects of climate change and potential barrage construction. An existing two-dimensional hydrodynamic model is outlined first. Three scenarios at the open seaward boundary are then presented. Finally, the model was used to simulate the hydrodynamic processes in the estuary using three boundary scenarios. Simulated results show that (i) without the barrage, the maximum levels along the estuary could rise by 1.0-1.2 m due to sea-level rise, and the effect of extreme sea levels on the distribution of maximum water levels would be noticeable only in the outer estuary reach; (ii) with the barrage, the maximum water levels could reduce by 0.5-1.2 m upstream of the barrage even if a sea-level rise of 1.0 m would occur by 2100, and extreme sea levels could not influence the distribution of maximum water levels upstream of the barrage; and (iii) the future flood risk in a small coastal floodplain would increase and the potential losses could reach d6.5 M/year due to sea-level rise without the barrage, and it could be avoided completely if the barrage were to be constructed as proposed.

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 analyze various equations concerning Strings and Higher Spins and some Starobinsky's formulas. We obtain new possible mathematical connections with the DN Constant, Ramanujan Recurring Numbers and some parameters of Number Theory and String Theory


UPDATED VERSION 28.03.2025

In this paper, we analyze various equations concerning the Number Theory and some Starobinsky's formulas. We obtain new possible mathematical connections with the DN Constant, Ramanujan Recurring Numbers and some parameters of Theoretical Cosmology and String Theory

In this paper, we analyze some Starobinsky's formulas and Brane Supersymmetry Breaking equations. We obtain new possible mathematical connections with the DN Constant, Ramanujan Recurring Numbers and some parameters of Number Theory and String Theory

Abstract: The world is heavily dependent on fossil fuels since most of its energy requirements are fulfilled by conventional methods of burning these fuels. The energy demand is increasing by day with growing population. The energy production by fossil fuels is devastating the environment and survival of life on globe is endangered. The renewal energy technologies are vital to ensure future energy sustenance and environmental issues. Ocean is a vast resource of renewable energy. The technology today makes it possible to ...

In this paper, we analyze various equations concerning DN Constant and various applications in Cosmology. We obtain new possible mathematical connections with DN Constant, Ramanujan Recurring Numbers and some parameters of Number Theory and String Theory

In this paper (part III), we analyze some equations concerning the Optimal Transport applied to the Classical Isoperimetric Inequality and to the Black Holes mathematics. We obtain various mathematical connections with MRB Constant, the "Ramanujan's Recurring Numbers" and some parameters of String Theory

The development of tidal energy in Australia is still a challenge with few studies performed on the characterisation of the resource, due to the difficulty to acquire data and uncertainties about the influence of this anthropogenic activity on the marine environment. Changes in flow could lead to alterations in sediment transport and have further influence on the marine habitat. A case study in a promising area, Banks Strait (Australia), was created using high resolution 2D and 3D models validated against in situ data to investigate changes to hydrodynamic conditions with two scenarios of tidal farms (100 and 300 turbines). Comparison between 2D and 3D is performed to find the best compromise between model accuracy and computational time for preliminary assessment. Changes to current speed and bed shear stress over a 35 day period were found to be localised around the tidal farms and did not extent more than 7 km from the farm (300 turbines) for both 2D and 3D. The results showed th...

Blade Element Momentum Theory (BEMT) is a computationally efficient method of calculating the performance of a tidal stream turbine (TST) generating energy from the ocean. This efficiency is achieved by making several simplifying assumptions; an unintended consequence of these assumptions is the omission of some phenomena that can significantly alter the performance and loads of a TST. We can ameliorate this by incorporating suitable corrections into a BEMT model, which allow us to account for some of the effects of these phenomena. This paper examines the implementation of corrections in an established BEMT solver for two such phenomena: tip/hub losses and high induction conditions. Tip losses are attributable to the flow of fluid around end of the blade, a flow feature omitted in the classical BEMT treatment of turbines. At high tip speed ratios, above the designed operating range of the device, the theory based on an axial interference factor, a, diverges from experimental results and, indeed, becomes physically untenable. Buhl proposed a high induction correction factor for wind turbines operating in air and a modified version of his correction is implemented here for a TST operating in water. The tip/hub loss and high-induction corrections are well-integrated with one another. The validity of the high-induction correction is checked against experimental results; we find that our model predicts power output well but overpredicts axial thrust compared to laboratory observations.

A modelling approach based on Blade Element Momentum Theory is developed for the prediction of tidal stream turbine performance in the ocean environment. Through the coupling of the Blade Element Momentum method with Computational Fluid Dynamics, the influence of upstream hydrodynamics on rotor performance is accounted for. Incoming flow onto the rotor can vary in speed and direction compared to free-stream conditions due to the presence of obstructions to the flow in the upstream, due to other devices for example, or due to the complexity of natural bathymetries. The relative simplicity of the model leads to short run times and a lower demand on computational resources making it a useful tool for considering more complex engineering problems consisting of multiple tidal stream turbines. Results from the model compare well against both measured data from flume experiments and results obtained using the Classical Blade Element Momentum model. A discussion considering the advantages and disadvantages of these different approaches is included.

In this paper (part III), we analyze various equations concerning the "Black Holes, Quantum Cosmology and Negative Dimensions" and the Riemann Zeta Function. We obtain mathematical connections with the MRB constant, Ramanujan Recurring Numbers, various parameters of Number Theory and some sectors of String Theory

v2 - 03.03.2025

The objective of GHYDRO, a France Energies Marines project, is to draw up a methodology guide that provide stakeholders in tidal stream energy projects with decision-making help for the environmental integration of generators and tidal farms. The methodological guide currently represents a summary of the recommendations concerning the diverse physical parameters and biological compartments of the ecosystems that are potentially affected. The physical and biological compartments of the marine ecosystems have been addressed separately in the guide, in order to propose methodologies adapted to each one, in relation to the establishment of the initial state, the characterisation of the potential impacts and the environmental monitoring. To bring together the broadest range of expertise, France Energies Marines has created a consortium of specialists in tidal power technologies and in the marine environment coming from both research institutes and companies.

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.

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.

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 ...

The Gradient Scheme framework provides a unified analysis setting for many different families of numerical methods for diffusion equations. We show in this paper that the Gradient Scheme framework can be adapted to elasticity equations, and provides error estimates for linear elasticity and convergence results for non-linear elasticity. We also establish that several classical and modern numerical methods for elasticity are embedded in the Gradient Scheme framework, which allows us to obtain convergence results for these methods in cases where the solution does not satisfy the full H 2 -regularity or for non-linear models.

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.

In this paper (part III), we analyze some equations concerning the Inclined Plane Trigonometry. We obtain new possible mathematical connections with Ramanujan Recurring Numbers, DN Constant and some parameters of Number Theory and String Theory

In order to reduce greenhouse-gas emissions by 55 % below 1990 levels by 2030, the European Commission advocates for increased integration of renewable energy sources. This paper examines the role of energy hubs (EH) or multi-energy systems (MES) in achieving this goal. It evaluates the effectiveness of bifacial photovoltaic panels (BPV), tidal turbines, and hydrogen production in enhancing EH performance. Moreover, carbon capture (CCUS) technology is explored for its ability to safely use fossil fuels and reduce costs by utilizing captured CO2 in oil refineries. Due to their significant energy consumption, crypto miners' impact is also analyzed alongside demand response programs to assess their combined effect on EH performance. The primary objective has been to enhance sustainability and optimize the energy hub's performance by minimizing total costs and environmental pollution. The problem is modeled as mixed integer linear programming (MILP) and solved in GAMS software by utilizing diverse solvers to evaluate the accuracy of the results. The results show the effectiveness of the proposed planning; therefore, by bi-facial PV, total cost decreased by approximately 2.51 % from $546.433 to $532.7, and environmental pollution reduced by about 1.80 % from 2669.538 kg to 2621.388 kg. CCUS technology causes a reduction in total pollution by approximately 89.66 %, down to 270.831 kg. Demand response programs flatter the load curve and enhance the energy hub's reliability. The power sold to the main grid decreased by approximately 28.10 %, from 1511.725 kW to 1086.931 kW, indicating a more efficient internal use of generated power and better demand management.

In this paper, we analyze the Einstein Field Equation and Second Friedmann Equation. We obtain new possible mathematical connections with DN Constant, Ramanujan Recurring Numbers and some parameters of Number Theory and String Theory

UPDATED VERSION - 20.12.2024

In this paper, we analyze some formulas concerning the Boyarsky-Meyers estimates and perform the study of a Cubic Equation. We obtain new possible mathematical connections with DN Constant, Ramanujan Recurring Numbers and some parameters of Number Theory and String Theory

In this study, different numerical models are computed and compared with particle image velocimetry (PIV) measurement for wake correlation of a 4.5 m of diameter wind turbine rotor. The collaborative European wind turbine MEXICO project is carried out in three commonly experimental defined test cases at wind speeds of 10, 15 and 24 m.s-1. To discuss the rotor near wake, a laminar Navier-Stokes approach and a Reynolds averaged Navier-Stokes turbulent model both coupled with an actuator disc (AD) technique are computed, then compared with a direct model from the literature called TAU/DM as a full rotor technique. The actuator disc momentums are calculated using user defined functions (UDF) in FLUENT introduced as UDF/AD technique in this paper. The results are discussed in detail and compared with PIV detailed measurements.

This review provides a critical, multi-faceted assessment of the practical contribution tidal stream energy can make to the UK and British Channel Islands future energy mix. Evidence is presented that broadly supports the latest national-scale practical resource estimate, of 34 TWh/year, equivalent to 11% of the UK’s current annual electricity demand. The size of the practical resource depends in part on the economic competitiveness of projects. In the UK, 124 MW of prospective tidal stream capacity is currently eligible to bid for subsidy support (MeyGen 1C, 80 MW; PTEC, 30 MW; and Morlais, 14 MW). It is estimated that the installation of this 124 MW would serve to drive down the levelized cost of energy (LCoE), through learning, from its current level of around 240   £ / MWh to below 150   £ / MWh , based on a mid-range technology learning rate of 17%. Doing so would make tidal stream cost competitive with technologies such as combined cycle gas turbines, biomass and anaerobic dig...

COST is supported by the EU Framework Programme Horizon 2020. COST (European Cooperation in Science and Technology) is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers.

This review provides a critical, multi-faceted assessment of the practical contribution tidal stream energy can make to the UK and British Channel Islands future energy mix. Evidence is presented that broadly supports the latest national-scale practical resource estimate, of 34 TWh/year, equivalent to 11% of the UK’s current annual electricity demand. The size of the practical resource depends in part on the economic competitiveness of projects. In the UK, 124 MW of prospective tidal stream capacity is currently eligible to bid for subsidy support (MeyGen 1C, 80 MW; PTEC, 30 MW; and Morlais, 14 MW). It is estimated that the installation of this 124 MW would serve to drive down the levelized cost of energy (LCoE), through learning, from its current level of around 240   £ / MWh to below 150   £ / MWh , based on a mid-range technology learning rate of 17%. Doing so would make tidal stream cost competitive with technologies such as combined cycle gas turbines, biomass and anaerobic dig...

The energy and water crisis due to the rapidly growing
population and developing societies caused countries and
governments to think about novel technologies and ways to
respond to this issue. Therefore, this paper is about energy
planning and management of the proposed concept for supplying
water and energy simultaneously. This approach helps to
overcome and supply the dramatic energy need of desalination
and distribution systems. This article aims to supply the demands
and minimize the total cost at the same time. Various renewable
and non-renewable energy resources such as tidal turbines,
INVELOX turbines, CHP, micro-turbines, and other elements
are utilized in the proposed planning. Real weather conditions
are considered to compute the output power of wind and tidal
turbines. The presented water-energy nexus structure is modeled
as a MINLP concept and solved in GAMS software using various
solvers to illustrate the reliability of the optimization answers.
The final results show a high improvement in the total cost
reduction.

The socio-economic developments of all nations depend duly on electrical energy supply. Nigeria as a country is faced with challenges of poor electric power supply due to the challenges from the power holding company of Nigeria (PHCN) which have left many households and isolated areas with no access to electricity. The fact that fossil fuel generators contributes to climate changes, renewable energy such as wind could be the best alternative. This paper presents the numerical design of an off-grid wind energy systems for powering load demand of two bedrooms apartment. The load demand of two bedroom flats were estimated and sizes of wind turbine, storage batteries and inverter with respect to typical load demand were numerically estimated. The performance of three 1 KW horizontal axis wind turbines of the same capacity but from different manufacturers namely; Bergey’s (BWC XL.1), Wind energy (WE.7) and Hummer wind energy (H3.1) were numerically tested  using the average monthly wind ...

In this paper, we analyze various Ramanujan's arithmetical functions. We obtain new possible mathematical connections with the Ramanujan Recurring Numbers, DN Constant and some parameters of Number Theory, Theoretical Cosmology and String Theory

This work is devoted to the numerical solution of the three dimensional (3D) compressible Navier-Stokes system on unstructured mesh. The numerical simulation are performed using a fractional step method treating separately the convection and the diffusion parts. The discretization is done by the finite volume method for the two parts. The convective flux is computed by the Godunov method and a new scheme is presented for the treatment of the diffusive flux. The technique is illustrated by solving various numerical problems.

Energy is the basic requirement for human life. At present most of the energy needs are met through fossil fuels and oil. But these are exhaustible resources. Therefore there is an urgent need all over world to tap renewable energy sources. Tides are a substantial potential source of clean renewable energy for future human generations and small communities or even individual households located near continental shorelines, straits or on remote islands with strong tidal currents. Taking an average (gρ) = 10.15kNm-3 for seawater, energy can be obtained for a tide cycle, per square meter of ocean surface: E = 1.4h2, watt-hour (5.04h2, kilojoules). The energy source estimated potential of tidal power is 10,000MW. This paper deals with the origin of tides, the energy associated with the tides and various technologies used for production of electricity using tidal energy.

Sentinel-1 (C-band imaging SAR) and Sentinel-2 (Multi Spectral Instrument) data are selected to match the required spatial and spectral resolution and repeat coverage to cope with the environmental gradients and heterogeneity across and among foreshores, and temporal variations resulting from e.g., tidal inundation and phenology. Algorithms will be developed to retrieve information on foreshore topography, vegetation structure and density, sediment type and stability from spaceborne imagery, with emphasis on Sentinel. They will be calibrated and validated with in situ data (via the centralized OpenEarth platform) at 8 pilot sites across Europe (Spain, Romania, United Kingdom and the Netherlands). Earth Observation (EO) information is combined with measurements on wave attenuation and erosion/deposition regimes to understand the functioning of foreshores.

We analyse numerical errors (dissipation and dispersion) introduced by the discretisation of inviscid and viscous terms in energy stable discontinuous Galerkin methods. First, we analyse these methods using a linear von Neumann analysis (for a linear advection-diffusion equation) to characterise their properties in wave-number space. Second, we validate these observations using the 3D Taylor-Green Vortex Navier-Stokes problem to assess transitional/turbulent flows. We show that the dissipation introduced by upwind Riemann solvers affects primarily high wave-numbers. This dissipation may be increased, through a penalty parameter, until a critical value. However, further augmentation of this parameter leads to a decrease of dissipation, reaching zero for very large values. Regarding the dissipation introduced by second order derivatives, we show that this dissipa- tion acts at low and medium wave-numbers (lower wave-numbers compared to upwind Riemann solvers). In addition, we analyse ...

Experimental results of the dynamics of a small scale concentric wave energy converter array adapted to a floating offshore platform are presented. A small scale prototype is tested without and with twelve conical heaving point absorbers. The free decay and regular wave tests are carried out in an ocean basin to understand the hydrodynamic interactions between various elements of the floating offshore platform and wave energy converter array. Meanwhile, the heave motions of the buoys are observed in regular waves with and without dampers for the initial estimation of power take-off damping as a pitch control module. The results show the improvements in heave, pitch, and roll performance of the platform due to the interactio n between the buoys and platform.

industrial research is being conducted for the development of related technologies. It is expected that Renewable Energy will be able to replace fossil fuels in the near future. Tidal current energy is one such concept that is attracting a lot of interest from the developers and researchers all over the world. It is a form of hydrokinetic energy extracted from the water flow in the tidal channels. Such flow takes place due to the relative motion of the gravitational fields of the moon, sun and earth [iv] as depicted in Fig. 1.