Modeling Assessment of Tidal Energy Extraction in the Western Passage

Numerical models have been widely used for the resource characterization and assessment of tidal instream energy. The accurate assessment of tidal stream energy resources at a feasibility or project-design scale requires detailed hydrodynamic model simulations or high-quality field measurements. This study applied a three-dimensional finite-volume community ocean model (FVCOM) to simulate the tidal hydrodynamics in the Passamaquoddy–Cobscook Bay archipelago, with a focus on the Western Passage, to assist tidal energy resource assessment. IEC Technical specifications were considered in the model configurations and simulations. The model was calibrated and validated with field measurements. Energy fluxes and power densities along selected cross sections were calculated to evaluate the feasibility of the tidal energy development at several hotspots that feature strong currents. When taking both the high current speed and water depth into account, the model results showed that the Western Passage has great potential for the deployment of tidal energy farms. The maximum extractable power in the Western Passage was estimated using the Garrett and Cummins method. Different criteria and methods recommended by the IEC for resource characterization were evaluated and discussed using a sensitivity analysis of energy extraction for a hypothetical tidal turbine farm in the Western Passage.

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Numerical modelling of hydrodynamics and tidal energy extraction in the Alderney Race: a review

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2019.0498 ◽

2020 ◽

Vol 378 (2178) ◽

pp. 20190498

Author(s):

Jérôme Thiébot ◽

D. S. Coles ◽

Anne-Claire Bennis ◽

Nicolas Guillou ◽

Simon Neill ◽

...

Keyword(s):

Numerical Modelling ◽

Three Dimensional ◽

Energy Resource ◽

Tidal Energy ◽

Resource Assessment ◽

Spatial Modelling ◽

Optimization Techniques ◽

Energy Extraction ◽

Model Case ◽

Eddy Simulation

The tides are a predictable, renewable, source of energy that, if harnessed, can provide significant levels of electricity generation. The Alderney Race (AR), with current speeds that exceed 5 m s −1 during spring tides, is one of the most concentrated regions of tidal energy in the world, with the upper-bound resource estimated at 5.1 GW. Owing to its significance, the AR is frequently used for model case studies of tidal energy conversion, and here we review these model applications and outcomes. We examine a range of temporal and spatial modelling scales, from regional models applied to resource assessment and characterization, to more detailed models that include energy extraction and array optimization. We also examine a range of physical processes that influence the tidal energy resource, including the role of waves and turbulence in tidal energy resource assessment and loadings on turbines. The review discusses model validation, and covers a range of numerical modelling approaches, from two-dimensional to three-dimensional tidal models, two-way coupled wave-tide models, Large Eddy Simulation (LES) models, and the application of optimization techniques. The review contains guidance on model approaches and sources of data that can be used for future studies of the AR, or translated to other tidal energy regions. This article is part of the theme issue ‘New insights on tidal dynamics and tidal energy harvesting in the Alderney Race’.

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HF Radars for Wave Energy Resource Assessment Offshore NW Spain

Remote Sensing ◽

10.3390/rs13112070 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2070

Author(s):

Ana Basañez ◽

Vicente Pérez-Muñuzuri

Keyword(s):

Wave Energy ◽

Numerical Models ◽

Wave Spectrum ◽

Energy Resource ◽

Electrical Energy ◽

Resource Assessment ◽

Electricity Production ◽

Statistical Validation ◽

Wave Energy Converters ◽

Energy Converters

Wave energy resource assessment is crucial for the development of the marine renewable industry. High-frequency radars (HF radars) have been demonstrated to be a useful wave measuring tool. Therefore, in this work, we evaluated the accuracy of two CODAR Seasonde HF radars for describing the wave energy resource of two offshore areas in the west Galician coast, Spain (Vilán and Silleiro capes). The resulting wave characterization was used to estimate the electricity production of two wave energy converters. Results were validated against wave data from two buoys and two numerical models (SIMAR, (Marine Simulation) and WaveWatch III). The statistical validation revealed that the radar of Silleiro cape significantly overestimates the wave power, mainly due to a large overestimation of the wave energy period. The effect of the radars’ data loss during low wave energy periods on the mean wave energy is partially compensated with the overestimation of wave height and energy period. The theoretical electrical energy production of the wave energy converters was also affected by these differences. Energy period estimation was found to be highly conditioned to the unimodal interpretation of the wave spectrum, and it is expected that new releases of the radar software will be able to characterize different sea states independently.

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Impact of Channel Geometry and Rotation on the Trapping of Internal Tides

Journal of Physical Oceanography ◽

10.1175/2007jpo3586.1 ◽

2007 ◽

Vol 37 (11) ◽

pp. 2740-2763 ◽

Cited By ~ 21

Author(s):

Sybren Drijfhout ◽

Leo R. M. Maas

Keyword(s):

Continental Slope ◽

Three Dimensional ◽

Tidal Energy ◽

Ocean Model ◽

Internal Tides ◽

Open Boundary ◽

Kelvin Wave ◽

Channel Geometry ◽

Channel Slope ◽

The Cross

Abstract The generation and propagation of internal tides has been studied with an isopycnic three-dimensional ocean model. The response of a uniformly stratified sea in a channel, which is forced by a barotropic tide on its open boundary, is considered. The tide progresses into the channel and forces internal tides over a continental slope at the other end. The channel has a length of 1200 km and a width of 191.25 km. The bottom profile has been varied. In a series of four experiments it is shown how the cross-channel geometry affects the propagation and trapping of internal tides, and the penetration scale of wave energy, away from the continental slope, is discussed. In particular it is found that a cross-channel bottom slope constrains the penetration of the internal tidal energy. Most internal waves refract toward a cross-channel plane where they are trapped. The exception is formed by edge waves that carry part of the energy away from the continental slope. In the case of rotation near the continental slope, the Poincaré waves that arise in the absence of a cross-channel slope no longer bear the characteristics of the wave attractor predicted by 2D theory, but are almost completely arrested, while the right-bound Kelvin wave preserves the 2D attractor in the cross-channel plane, which is present in the nonrotating case. The reflected, barotropic right-bound Kelvin wave acts as a secondary internal wave generator along the cross-channel slope.

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Quantification of Extent, Density, and Status of Aquatic Reed Beds Using Point Clouds Derived from UAV–RGB Imagery

Remote Sensing ◽

10.3390/rs10121869 ◽

2018 ◽

Vol 10 (12) ◽

pp. 1869 ◽

Cited By ~ 4

Author(s):

Nicolás Corti Meneses ◽

Florian Brunner ◽

Simon Baier ◽

Juergen Geist ◽

Thomas Schneider

Keyword(s):

Cross Sections ◽

Vegetation Index ◽

Low Cost ◽

Three Dimensional ◽

Field Measurements ◽

Point Clouds ◽

Conservation Strategies ◽

Reed Beds ◽

Combining Data ◽

Reed Bed

Quantification of reed coverage and vegetation status is fundamental for monitoring and developing lake conservation strategies. The applicability of Unmanned Aerial Vehicles (UAV) three-dimensional data (point clouds) for status evaluation was investigated. This study focused on mapping extent, density, and vegetation status of aquatic reed beds. Point clouds were calculated with Structure from Motion (SfM) algorithms in aerial imagery recorded with Rotary Wing (RW) and Fixed Wing (FW) UAV. Extent was quantified by measuring the surface between frontline and shoreline. Density classification was based on point geometry (height and height variance) in point clouds. Spectral information per point was used for calculating a vegetation index and was used as indicator for vegetation vitality. Status was achieved by combining data on density, vitality, and frontline shape outputs. Field observations in areas of interest (AOI) and optical imagery were used for reference and validation purposes. A root mean square error (RMSE) of 1.58 m to 3.62 m for cross sections from field measurements and classification was achieved for extent map. The overall accuracy (OA) acquired for density classification was 88.6% (Kappa = 0.8). The OA for status classification of 83.3% (Kappa = 0.7) was reached by comparison with field measurements complemented by secondary Red, Green, Blue (RGB) data visual assessments. The research shows that complex transitional zones (water–vegetation–land) can be assessed and support the suitability of the applied method providing new strategies for monitoring aquatic reed bed using low-cost UAV imagery.

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Numerical Models as Enabling Tools for Tidal-Stream Energy Extraction and Environmental Impact Assessment

Volume 6: Ocean Space Utilization; Ocean Renewable Energy ◽

10.1115/omae2016-54223 ◽

2016 ◽

Author(s):

Zhaoqing Yang ◽

Taiping Wang

Keyword(s):

Water Quality ◽

Unstructured Grid ◽

Puget Sound ◽

Tidal Energy ◽

Ocean Model ◽

Energy Extraction ◽

Volume Flux ◽

Quality Model ◽

Flushing Time ◽

Tidal Turbine

This paper presents a modeling study conducted to evaluate tidal-stream energy extraction and its associated potential environmental impacts using a three-dimensional unstructured-grid coastal ocean model, which was coupled with a water-quality model and a tidal-turbine module. The unstructured-grid tidal-turbine model was first applied to investigate the effects of different tidal farm configurations on tidal energy extraction and the effects on the system flow field as well as biogeochemical transport processes in an idealized bay with a narrow channel connecting to the coastal ocean. Model results indicated that a large number of turbines are required to extract the maximum tidal energy and cause significant reduction in the volume flux. Model results also showed that tidal energy extraction has a greater effect on flushing time than on volume flux reduction. In the idealized tidal channel, a 10% reduction of volume flux caused by tidal energy extraction would result in an approximately 50% increase in flushing time in the bay. The flushing time increases exponentially as a function of flow reduction. A water-quality model simulation was conducted to investigate the dynamic effect of tidal energy extraction on water quality in a stratified tidal channel and estuary system. Model results showed that deployment of tidal turbines in the channel would increase vertical mixing in the bay. However, extraction of tidal energy also would result in a decrease in bottom dissolved oxygen in the bay during summer, which may cause hypoxia in fish. Finally, the tidal-turbine model was applied to a real-world site in Puget Sound — a highly energetic estuary on the US Pacific Northwest coast. The model application of tidal energy extraction in Puget Sound demonstrated the advantage of using an unstructured-grid modeling approach with high grid resolution near the tidal-turbine farm within a large model domain. This study showed that a numerical model can be a useful tool for assessing tidal energy extraction and its environmental impacts and for informing regulatory and policy processes for tidal energy development.

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Tidal Energy Flows between the Midriff Islands in the Gulf of California

Energies ◽

10.3390/en14030621 ◽

2021 ◽

Vol 14 (3) ◽

pp. 621

Author(s):

Federico Angel Velazquez-Muñoz ◽

Anatoliy Filonov

Keyword(s):

Kinetic Energy ◽

Internal Wave ◽

Gulf Of California ◽

Current Flow ◽

Tidal Flow ◽

Three Dimensional ◽

Tidal Energy ◽

Ocean Model ◽

Field Development ◽

Wave Measurements

The Gulf of California has many regions of potential tidal-stream energy that have been identified and characterized using in-situ measurements and numerical ocean models. The Midriff Islands region has received particular attention due to its increased current speeds and high kinetic energy. This increase in energy can be seen in the formation of internal wave packets propagating for several hundred kilometers. Here we present a brief description of internal wave measurements travel towards the Northern Gulf and explore energy generation sites. In this paper we characterize the tidal inflow and outflow that passes throughout the Midriff Islands in the central part of the Gulf. We use a three-dimensional numerical ocean model that adequately reproduces the tidal flow and the increase in speed and kinetic energy between the islands. The current flow structure shows the highest velocity cores near the shore and far from the bottom. During the rising tide, the maximum current flow (~0.6 ms−1) was found between Turón Island and San Lorenzo Island, from the surface to 200 m depth. When the currents flowed out of the Gulf, during the falling tide, the maximum negative current (−0.8 ms−1) was found between Tiburon Island and Turón Island, from near the surface to 80 m depth. Although there are favorable conditions for power generation potential by tidal flows, the vertical variability of the current must be considered for field development and equipment installation sites.

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Effects on hydrodynamics and ecological costs of climate change and tidal stream energy extraction in a shelf sea

10.5194/egusphere-egu2020-11619 ◽

2020 ◽

Author(s):

Michela De Dominicis ◽

Judith Wolf ◽

Dina Sadykova ◽

Beth Scott ◽

Alexander Sadykov ◽

...

Keyword(s):

Climate Change ◽

Large Scale ◽

Climate Scenario ◽

Tidal Energy ◽

Ocean Model ◽

Future Climate ◽

Biogeochemical Model ◽

Energy Extraction ◽

Shelf Sea ◽

Tidal Stream

<p>The aim of this work is to analyse the potential impacts of tidal energy extraction on the marine environment. We wanted to put them in the broader context of the possibly greater and global ecological threat of climate change. Here, we present how very large (hypothetical) tidal stream arrays and a ''business as usual'' future climate scenario can change the hydrodynamics of a seasonally stratified shelf sea, and consequently modify ecosystem habitats and animals&#8217; behaviour.</p><p>The Scottish Shelf Model, an unstructured grid three-dimensional ocean model, has been used to reproduce the present and the future state of the NW European continental shelf. While the marine biogeochemical model ERSEM (European Regional Seas Ecosystem Model) has been used to describe the corresponding biogeochemical conditions. Four scenarios have been modelled: present conditions and projected future climate in 2050, each with and without very large scale tidal stream arrays in Scottish Waters (UK). This allows us to evaluate the potential effect of climate change and large scale energy extraction on the hydrodynamics and biogeochemistry. We found that climate change and tidal energy extraction both act in the same direction, in terms of increasing stratification due to warming and reduced mixing, however, the effect of climate change is ten times larger. Additionally, the ecological costs and benefits of these contrasting pressures on mobile predator and prey marine species are evaluated using ecological statistical models.</p>

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Implementation of Tidal Stream Turbines and Tidal Barrage Structures in DG-SWEM

Volume 10: Ocean Renewable Energy ◽

10.1115/omae2019-95767 ◽

2019 ◽

Cited By ~ 3

Author(s):

Andrea M. Schnabl ◽

Tulio Marcondes Moreira ◽

Dylan Wood ◽

Ethan J. Kubatko ◽

Guy T. Houlsby ◽

...

Keyword(s):

Numerical Models ◽

Shallow Water Equation ◽

Tidal Energy ◽

Head Loss ◽

Equation Model ◽

Energy Extraction ◽

Tidal Hydrodynamics ◽

Low Head ◽

Tidal Stream ◽

Two Sides

Abstract There are two approaches to extracting power from tides — either turbines are placed in areas of strong flows or turbines are placed in barrages enabling the two sides of the barrage to be closed off and a head to build up across the barrage. Both of these energy extraction approaches will have a significant back effect on the flow, and it is vital that this is correctly modelled in any numerical simulation of tidal hydrodynamics. This paper presents the inclusion of both tidal stream turbines and tidal barrages in the depth-averaged shallow water equation model DG-SWEM. We represent the head loss due to tidal stream turbines as a line discontinuity — thus we consider the turbines, and the energy lost in local wake-mixing behind the turbines, to be a sub-grid scale processes. Our code allows the inclusion of turbine power and thrust coefficients which are dependent on Froude number, turbine blockage, and velocity, but can be obtained from analytical or numerical models as well as experimental data. The barrage model modifies the existing culvert model within the code, replacing the original cross-barrier pipe equations. At the location of this boundary, velocities through sluice gates are calculated according to the orifice equation. For simulating the turbines, a Hill Chart for low head bulb turbines provided by Andritz Hydro is used. We demonstrate the implementations on both idealised geometries where it is straightforward to compare against other models and numerical simulations of real candidate sites for tidal energy in Malaysia and the Bristol Channel.

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Wave Energy Resource Assessment for Exploitation—A Review

Journal of Marine Science and Engineering ◽

10.3390/jmse8090705 ◽

2020 ◽

Vol 8 (9) ◽

pp. 705 ◽

Cited By ~ 1

Author(s):

Nicolas Guillou ◽

George Lavidas ◽

Georges Chapalain

Keyword(s):

Wave Energy ◽

Energy Resource ◽

Resource Assessment ◽

Wave Climate ◽

Maximum Efficiency ◽

Physical Processes ◽

Wide Range ◽

Technical Specifications ◽

Reduced Costs

Over recent decades, the exploitation of wave energy resources has sparked a wide range of technologies dedicated to capturing the available power with maximum efficiency, reduced costs, and minimum environmental impacts. These different objectives are fundamental to guarantee the development of the marine wave energy sector, but require also refined assessments of available resource and expected generated power to optimize devices designs and locations. We reviewed here the most recent resource characterizations starting from (i) investigations based on available observations (in situ and satellite) and hindcast databases to (ii) refined numerical simulations specifically dedicated to wave power assessments. After an overall description of formulations and energy metrics adopted in resource characterization, we exhibited the benefits, limitations and potential of the different methods discussing results obtained in the most energetic locations around the world. Particular attention was dedicated to uncertainties in the assessment of the available and expected powers associated with wave–climate temporal variability, physical processes (such as wave–current interactions), model implementation and energy extraction. This up-to-date review provided original methods complementing the standard technical specifications liable to feed advanced wave energy resource assessment.

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Simulation and Experimental Study of Ultrasonic Cleaning Based on Multi-Field Coupling

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.816-817.1270 ◽

2013 ◽

Vol 816-817 ◽

pp. 1270-1273

Author(s):

Qing Dong Hao ◽

Fang Yi Li ◽

Bao Long Gong

Keyword(s):

Cross Sections ◽

Staining Method ◽

Three Dimensional ◽

Sound Field ◽

Field Measurements ◽

Comsol Multiphysics ◽

Ultrasonic Cleaning ◽

Field Coupling ◽

Cleaning Machine ◽

Three Dimensional Models

In current Ultrasonic Cleaning simulation, high calculation complexity and low precision is a big problem. The disadvantages of reflecting the sound field characteristics inaccurately and quantitative difficulties exist in the sound field measurements. Firstly, the two-dimensional and three-dimensional models of Ultrasonic Cleaning are established in COMSOL Multiphysics and corresponding cleaning effects under different frequencies are simulated, then the frequencies of cleaning machine suitable for remanufactured components are determined. Finally, by means of staining method, sound field distribution on different work cross-sections in the Ultrasonic Cleaning process is studied. Halcon and Matlab are used in our investigation to deal with the experiment results in order to provide a new idea on the measurement of the sound field of Ultrasonic Cleaning.

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