IMPLEMENTATION AND TESTING OF A POWER MATRIX-BASED WAVE ENERGY CONVERSION MODEL AND THE EFFECT SIMULATED ON THE WAVE FIELD — CASE STUDY OF LAGUNA, SC, BRAZIL

Electrical energy has become an essential resource for mankind and, as the population and technological dependency grow, also does the electricity demand. This necessity boosted numerous studies which focus on clean and renewable energy sources. Ocean wave energy is one of the most environmentally friendly sources of energy since it does not emit pollutants to the atmosphere and does not produce harmful waste. Another positive point about ocean waves is that they are inexhaustible, therefore a power plant could, potentially, provide energy indefinitely. Hence the object of this study is to estimate the wave energy reduction caused by the presence of wave energy conversion (WEC) devices near the coastline of Laguna, Brazil. In order to study the coastal impact of a WEC farm, the third generation sea state model TOMAWAC was used to simulate the waves on the Southern Brazilian Shelf under two different conditions, with and without the presence of an array of WECs. The results show that the mean significant wave height in the blockaded area undergoes a slight drop, caused by the presence of the WECs, which do not appear in the other scenario. But this reduction of the significant wave height is negligible compared to the order of magnitude of the wave height itself.

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Kajian Energi Gelombang Laut Di Daerah Abrasi Serangai, Bengkulu Utara Melalui Pengamatan Tinggi Gelombang Laut

INDONESIAN JOURNAL OF APPLIED PHYSICS ◽

10.13057/ijap.v11i2.49914 ◽

2021 ◽

Vol 11 (2) ◽

pp. 143

Author(s):

Ashar Muda Lubis ◽

Yosi Apriani Putri ◽

Rio Saputra ◽

Juhendi Sinaga ◽

M Hasanudin ◽

...

Keyword(s):

Wave Height ◽

Wave Energy ◽

Seasonal Variations ◽

Coastal Area ◽

Significant Wave Height ◽

Ocean Waves ◽

Wave Period ◽

Maximum Wave Height ◽

Significant Wave ◽

Sea Wave

The Serangai area, Batik Nau District, North Bengkulu has the highest average abrasion speed of 20 m/year. The abrasion could cause the coastal area to erode the coastline till several tens of meters. The purpose of this study was to determine the height of the ocean waves and to determine the energy of the ocean waves that has the potential to accelerate the abrasion process in the Serangai area. The research was carried out on November 5-7, 2018 in the Serangai beach area at a depth of 5 m using SBE 26 Plus Seagauge Wave equipment. The results showed that the observed wave height was between 0.8-1.6 m with a significant wave height (Hs) of 1.38 m. In addition, the wave period ranges from 5-11 s with a significant wave period (Ts) of 8.2 s. The result also shows that the maximum wave height of 1.6 m occurred on November 7, 2018 with maximum wave energy of 1800 J/m2. This result can perhaps accelerate the abrasion process in the Serangai area. It can also be seen that the wave height in the Serangai region is higher than in several other areas in Indonesia. However, it is necessary to continue observing the wave height to see the seasonal variations in sea wave height in Serangai area.

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Estimation of Significant Wave Heights from ASCAT Scatterometer Data via Deep Learning Network

Remote Sensing ◽

10.3390/rs13020195 ◽

2021 ◽

Vol 13 (2) ◽

pp. 195

Author(s):

He Wang ◽

Jingsong Yang ◽

Jianhua Zhu ◽

Lin Ren ◽

Yahao Liu ◽

...

Keyword(s):

Deep Learning ◽

Wave Height ◽

Significant Wave Height ◽

Incidence Angle ◽

Ocean Waves ◽

Global Scale ◽

Learning Technology ◽

Sea State ◽

Significant Wave ◽

Wave Heights

Sea state estimation from wide-swath and frequent-revisit scatterometers, which are providing ocean winds in the routine, is an attractive challenge. In this study, state-of-the-art deep learning technology is successfully adopted to develop an algorithm for deriving significant wave height from Advanced Scatterometer (ASCAT) aboard MetOp-A. By collocating three years (2016–2018) of ASCAT measurements and WaveWatch III sea state hindcasts at a global scale, huge amount data points (>8 million) were employed to train the multi-hidden-layer deep learning model, which has been established to map the inputs of thirteen sea state related ASCAT observables into the wave heights. The ASCAT significant wave height estimates were validated against hindcast dataset independent on training, showing good consistency in terms of root mean square error of 0.5 m under moderate sea condition (1.0–5.0 m). Additionally, reasonable agreement is also found between ASCAT derived wave heights and buoy observations from National Data Buoy Center for the proposed algorithm. Results are further discussed with respect to sea state maturity, radar incidence angle along with the limitations of the model. Our work demonstrates the capability of scatterometers for monitoring sea state, thus would advance the use of scatterometers, which were originally designed for winds, in studies of ocean waves.

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Physical Modelling of the Effect on the Wave Field of the WaveCat Wave Energy Converter

Journal of Marine Science and Engineering ◽

10.3390/jmse9030309 ◽

2021 ◽

Vol 9 (3) ◽

pp. 309

Author(s):

James Allen ◽

Gregorio Iglesias ◽

Deborah Greaves ◽

Jon Miles

Keyword(s):

Wave Height ◽

Wave Energy ◽

Significant Wave Height ◽

Wedge Angle ◽

Wave Energy Converter ◽

Wave Period ◽

Surface Elevation ◽

Energy Converter ◽

Significant Wave ◽

Model Scale

The WaveCat is a moored Wave Energy Converter design which uses wave overtopping discharge into a variable v-shaped hull, to generate electricity through low head turbines. Physical model tests of WaveCat WEC were carried out to determine the device reflection, transmission, absorption and capture coefficients based on selected wave conditions. The model scale was 1:30, with hulls of 3 m in length, 0.4 m in height and a freeboard of 0.2 m. Wave gauges monitored the surface elevation at discrete points around the experimental area, and level sensors and flowmeters recorded the amount of water captured and released by the model. Random waves of significant wave height between 0.03 m and 0.12 m and peak wave periods of 0.91 s to 2.37 s at model scale were tested. The wedge angle of the device was set to 60°. A reflection analysis was carried out using a revised three probe method and spectral analysis of the surface elevation to determine the incident, reflected and transmitted energy. The results show that the reflection coefficient is highest (0.79) at low significant wave height and low peak wave period, the transmission coefficient is highest (0.98) at low significant wave height and high peak wave period, and absorption coefficient is highest (0.78) when significant wave height is high and peak wave period is low. The model also shows the highest Capture Width Ratio (0.015) at wavelengths on the order of model length. The results have particular implications for wave energy conversion prediction potential using this design of device.

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Sea State Estimation Based on Ship Motions Measurements and Data Fusion

Volume 5: Ocean Engineering ◽

10.1115/omae2013-10657 ◽

2013 ◽

Author(s):

Céline Drouet ◽

Nicolas Cellier ◽

Jérémie Raymond ◽

Denis Martigny

Keyword(s):

Data Fusion ◽

State Estimation ◽

Wave Height ◽

Significant Wave Height ◽

Wave Spectrum ◽

Ocean Waves ◽

Ship Motions ◽

Sea State ◽

Significant Wave ◽

X Band

In-service monitoring can help to increase safety of ships especially regarding the fatigue assessment. For this purpose, it is compulsory to know the environmental conditions encountered: wind, but also the full directional wave spectrum. During the EU TULCS project, a full scale measurements campaign has been conducted onboard the CMA-CGM 13200 TEU container ship Rigoletto. She has been instrumented to measure deformation of the ship as well as the sea state encountered during its trip. This paper will focus on the sea state estimation. Three systems have been installed to estimate the sea state encountered by the Rigoletto: An X-band radar from Ocean Waves with WAMOS® system and two altimetric wave radars from RADAC®. Nevertheless, the measured significant wave height can be disturbed by several external elements like bow waves, sprays, sea surface ripples, etc… Furthermore, ship motions are also measured and can provide another estimation of the significant wave height using a specific algorithm developed by DCNS Research for the TULCS project. As all those estimations are inherently different, it is necessary to make a fusion of those data to provide a single estimation (“best estimate”) of the significant wave height. This paper will present the data fusion process developed for TULCS and show some first validation results.

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Performance of Linear Generator Designs for Direct Drive Wave Energy Converter under Unidirectional Long-Crested Random Waves

Energies ◽

10.3390/en14165098 ◽

2021 ◽

Vol 14 (16) ◽

pp. 5098

Author(s):

Budi Azhari ◽

Fransisco Danang Wijaya ◽

Edwar Yazid

Keyword(s):

Output Power ◽

Wave Height ◽

Wave Energy ◽

Significant Wave Height ◽

Analytical Calculation ◽

Weight Ratio ◽

Peak Frequency ◽

Random Waves ◽

Direct Drive ◽

Significant Wave

For generating electricity, direct-drive wave energy converters (WECs) with linear permanent magnet generators (LPMGs) have advantages in terms of efficiency, simplicity, and force-to-weight ratio over WEC with rotary generators. However, the converter’s work under approaching-real wave conditions should be investigated. This paper studies the performance of a pico-scale WEC with two different LPMGs under unidirectional long-crested random waves. Different significant wave heights (using data in the Southern Ocean of Yogyakarta, Indonesia) and peak frequencies are tested. The JONSWAP energy spectrum is used to extract the wave elevations, while the MSS toolbox in MATLAB Simulink is employed to solve the floater’s dynamic responses. Next, the translator movements are extracted and combined with the flux distribution from FEMM simulation and analytical calculation, and the output powers are obtained. An experiment is conducted to test the output under constant speed. The results show for both designs, different tested significant wave height values produce higher output powers than peak frequency variation, but there is no specific trend on them. Meanwhile, the peak frequency is inversely proportional to the output power. Elimination of the non-facing events results in increasing output power under both parameters’ variation, with higher significant wave height resulting in a bigger increase. The semi iron-cored LPMG produces lower power loss and higher efficiency.

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Wave Climate Analysis for a Wave Energy Conversion Application in Brazil

Volume 1: Offshore Technology; Special Symposium on Ocean Measurements and Their Influence on Design ◽

10.1115/omae2007-29597 ◽

2007 ◽

Cited By ~ 2

Author(s):

Eliab R. Beserra ◽

Andre´ L. T. Mendes ◽

Segen F. Estefen ◽

Carlos E. Parente

Keyword(s):

Energy Conversion ◽

Wave Energy ◽

Wind Waves ◽

Energy Resource ◽

Wave Climate ◽

Northern Coast ◽

Wave Energy Conversion ◽

Annual Fluctuation ◽

Significant Wave ◽

Climate Analysis

A variety of ocean wave energy conversion devices have been proposed worldwide considering different technology and energy extraction methods. In order to support full-scale prototype design and performance assessments of a conversion scheme to be deployed on the northern coast of Brazil, a long-term wave climate analysis is under development. A 5-year pitch-roll buoy data series has been investigated through an adaptive technique to enhance spatial resolution and allow for accurate wave directionality evaluation. Device design most influential variables such as extreme significant wave height, peak period and directionality were considered. Temporal variability in wave energy levels was particularly investigated for energy resource assessment. The major findings of this work include the narrow directional amplitude of the incident wave and higher significant wave heights of locally generated waves. The estimated energy resource levels agreed well with literature, also showing little annual fluctuation. The wave climate demonstrated to be in full agreement with the large-scale Equatorial Atlantic atmospheric variability, dominated by either local wind waves or by distant storm swells.

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Inferring significant wave height from seismic data: A comparison between methods.

10.5194/egusphere-egu21-14837 ◽

2021 ◽

Author(s):

Francisco Bolrão ◽

Co Tran ◽

Miguel Lima ◽

Sheroze Sheriffdeen ◽

Diogo Rodrigues ◽

...

Keyword(s):

Real Time ◽

Wave Height ◽

Seismic Data ◽

Significant Wave Height ◽

Transfer Functions ◽

Seismic Station ◽

Meteorological Data ◽

Ocean Waves ◽

The United States ◽

Significant Wave

The most pervasive seismic signal recorded on our planet &#8211; microseismic ambient noise -results from the coupling of energy between atmosphere, oceans and solid Earth. Because it carries information on ocean waves (source), the microseismic wavefield can be advantageously used to image ocean storms. This imaging is of interest both to climate studies &#8211; by extending the record of oceanic activity back into the early instrumental seismic record &#8211; and to real-time monitoring &#8211; where real-time seismic data can potentially be used to complement the spatially dense but temporally sparse satellite meteorological data. In our work, we develop empirical transfer functions between seismic observations and ocean activity observations, in particular, significant wave height. We employ three different approaches: 1) The approach of Ferretti et al (2013), who compute a seismic significant wave height and invert only for the empirical conversion parameters between oceanic and seismic significant wave heights; 2) The classical approach of Bromirski et al (1999), who computed an empirical transfer function between ground-motion recorded at a coastal seismic station and significant wave height measured at a nearby ocean buoy; and 3) A novel recurrent neural-network (RNN) approach to infer significant wave height from seismic data.&#160; We apply the three approaches to seismic and ocean buoy data recorded in the east coast of the United States. All three approaches are able to successfully predict ocean significant wave height from the seismic data. We compare the three approaches in terms of accuracy, computational effort and robustness. In addition, we investigate the regimes where each approach works best. &#160;The results show that the RNN approach is able to predict well the significant wave height recorded at the buoy. The prediction is improved if several nearby seismic stations are used rather than just one.&#160; This work is supported by FCT through projects UIDB/50019/2020 &#8211; IDL and UTAP-EXPL/EAC/0056/2017 - STORM.

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Wave Energy Assessment in the Bohai Sea and the Yellow Sea Based on a 40-Year Hindcast

Water ◽

10.3390/w12082087 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2087

Author(s):

Jie Dong ◽

Jian Shi ◽

Jianchun Zhao ◽

Chi Zhang ◽

Haiyan Xu

Keyword(s):

Wave Height ◽

Wave Energy ◽

Yellow Sea ◽

Significant Wave Height ◽

Bohai Sea ◽

The Yellow Sea ◽

Wave Power ◽

Power Flux ◽

Significant Wave ◽

The Bohai Sea

A wave hindcast, covering the period of 1979–2018, was preformed to assess wave energy potential in the Bohai Sea and the Yellow Sea. The hindcase was carried out using the third generation wave model TOMAWAC with high spatio-temporal resolution (about 1 km and on an hourly basis). Results show that the mean values of significant wave height increase from north to south, and the maximum values are located at the south part of the Yellow Sea with amplitude within 1.6 m. The magnitudes of significant wave height values vary significantly within seasons; they are at a maximum in winter. The wave energy potential was represented by distributions of the wave power flux. The largest values appear in the southeast part of the numerical domain with wave power flux values of 8 kW/m. The wave power flux values are less than 2 kW/m in the Bohai Sea and nearshore areas of the Yellow Sea. The seasonal mean wave power flux was found up to 8 kW/m in the winter and autumn. To investigate the exploitable wave energy, a wave energy event was defined based on the significant wave height (Hs) threshold values of 0.5 m. The wave energy in south part of the Yellow Sea is more steady and intensive than in the other areas. Wave energy in winter is more suitable for harvesting wave energy. Long-term trends of wave power availability suggest that the values of wave power slightly decreased in the 1990s, whereas they have been increasing since 2006.

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An Analysis of a Stationary Pneumatic Wave-Energy Converter

Journal of Engineering for Industry ◽

10.1115/1.3438651 ◽

1975 ◽

Vol 97 (3) ◽

pp. 1015-1019 ◽

Cited By ~ 1

Author(s):

Michael E. McCormick

Keyword(s):

Theoretical Analysis ◽

Energy Conversion ◽

Wave Height ◽

Wave Energy ◽

Power Output ◽

Peak Power ◽

Peak Power Output ◽

Wave Energy Conversion ◽

Energy Converter ◽

Resonant Period

A theoretical analysis of a stationary pneumatic wave-energy conversion device is presented. Results obtained from the analysis show that the power converted is proportional to the cube of the wave height, producing a maximum time-averaged power per wave period of 25 kw for a 20-ft (6.096 m) diameter unit located in a 3-ft (0.9144 m) sea. The device can be adjusted for purposes of efficiency in any sea spectrum by simply changing the draft (length of the centerpipe) of the unit. The peak power output of the device occurs at a period similar to the resonant period of a surge chamber.

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Modelling of Sea Storms Associated With Energy Harvesters: Downtime and Energy Losses

Volume 9: Ocean Renewable Energy ◽

10.1115/omae2015-42178 ◽

2015 ◽

Author(s):

Felice Arena ◽

Valentina Laface ◽

Giovanni Malara ◽

Alessandra Romolo

Keyword(s):

Wave Height ◽

Wave Energy ◽

Significant Wave Height ◽

Safety Margin ◽

Wave Climate ◽

Energy Losses ◽

Critical Element ◽

Significant Wave ◽

Energy Harvesters ◽

Extreme Loads

The design of an energy harvester involves achieving the two following objectives: to install a safe structure with a reasonable safety margin; and to install an effective device which is able to capture energy in a variety of environmental conditions. In this context, the long-term modelling of the environmental variables plays a crucial role. In the context of wave energy harvesters, the occurrence of sea storms is a critical element in the design process. Indeed, its identification is required for determining extreme loads as well as controlled de-activations of the device for preserving the mechanical components into the device. Considering these issues, the paper proposes an analysis of the wave climate oriented to the determination of the downtime and of the energy losses. Specifically, the paper provides expressions: for calculating the average deactivation time of a wave energy device, given that it must be deactivated if the significant wave height is larger than a certain threshold; and for calculating the energy “lost” (as it is not absorbed by the device) during a storm in which the maximum wave height is larger than the mentioned threshold. The paper shows that closed-form expressions can be obtained by relying on the Equivalent Triangular Storm (ETS) model and that the adequacy of the estimations improves for larger values of the significant wave height threshold.

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